JP7789655B2 - Method for manufacturing thermosetting resin film, composite sheet, and semiconductor chip with first protective film - Google Patents

Description

The present invention relates to a thermosetting resin film, a composite sheet, and a method for manufacturing a semiconductor chip with a first protective film.
This application claims priority based on Japanese Patent Application No. 2020-031717, filed on February 27, 2020, the contents of which are incorporated herein by reference.

Traditionally, when mounting high-pin LSI packages used in MPUs, gate arrays, etc. on printed wiring boards, semiconductor chips with convex electrodes (hereinafter referred to as "bumps" in this specification) made of eutectic solder, high-temperature solder, gold, etc. on their connection pads have been used, and the so-called face-down method of flip-chip mounting has been used, in which these bumps are brought face-to-face and into contact with corresponding terminal portions on the chip-mounting substrate, and melt/diffusion bonded.

The semiconductor chips used in this packaging method are obtained, for example, by grinding or dicing the surface opposite the circuit surface (i.e., the bump-formed surface) of a semiconductor wafer with bumps formed on its circuit surface into individual pieces. In the process of obtaining such semiconductor chips, a thermosetting resin film is typically applied to the bump-formed surface of the semiconductor wafer to protect the bumps and the bumps themselves, and this film is then thermally cured to form a protective film on the bump-formed surface.

At the same time, semiconductor devices are expected to have higher functionality, and the size of semiconductor chips is tending to increase. However, larger-sized semiconductor chips are more likely to warp when mounted on a substrate, causing the bumps to deform, and cracks are particularly likely to occur in the bumps located at or near the edges of the semiconductor chip. A protective film formed on the bump-forming surface is also expected to suppress such bump damage.

A method for forming a protective film on the bump-formed surface of a semiconductor wafer will be described with reference to FIGS. 8A to 8D.
8A, a protective film formation sheet 8 is used. The protective film formation sheet 8 is configured by laminating an adhesive layer 83 and a thermosetting resin film 82 in this order on a substrate 81.

First, the protective film forming sheet 8 is placed so that the thermosetting resin film 82 faces the bump forming surface 9 a of the semiconductor wafer 9 .
Next, the protective film formation sheet 8 is pressed against the semiconductor wafer 9, and as shown in Fig. 8B, the thermosetting resin film 82 of the protective film formation sheet 8 is bonded to the bump formation surface 9a of the semiconductor wafer 9. The bonding of the thermosetting resin film 82 at this time is performed while heating the thermosetting resin film 82. As a result, the thermosetting resin film 82 is in close contact with the bump formation surface 9a of the semiconductor wafer 9 and the surfaces 91a of the bumps 91, and if the bumps 91 penetrate the thermosetting resin film 82, the adhesive layer 83 is also in close contact with part of the surface 91a of the bumps 91.
After laminating the thermosetting resin film 82 in this manner, if necessary, the surface (back surface) 9b of the semiconductor wafer 9 opposite the bump-forming surface 9a is ground, and then a protective film-forming sheet is separately attached to the back surface 9b of the semiconductor wafer 9 to protect this back surface 9b (not shown).

Next, as shown in FIG. 8C, the base material 81 and the adhesive layer 83 are removed from the thermosetting resin film 82.
Next, the thermosetting resin film 82 is thermally cured to form a protective film 82' as shown in FIG. 8D.

As such, a protective film forming sheet capable of forming a protective film on the bump formation surface of a semiconductor wafer has been disclosed, which is a thermosetting resin film having a melt viscosity within a specific range and an adhesive layer having a shear modulus within a specific range at a specific temperature range (see Patent Document 1).

Japanese Patent Application Publication No. 2015-092594

Various methods are known for dividing semiconductor wafers into semiconductor chips. One example involves using a semiconductor wafer with a groove on its bump-formed surface, which serves as the dividing point. As explained above, the backside of the semiconductor wafer is ground, so that the ground surface (backside) reaches the groove, thereby dividing the semiconductor wafer into semiconductor chips. The side of the groove becomes the side of the semiconductor chip. When this method is used, if a thermosetting resin film from a protective film-forming sheet is bonded to the bump-formed surface of the semiconductor wafer prior to dividing the semiconductor wafer, and the groove is sufficiently filled with the thermosetting resin film, the semiconductor wafer is divided and the thermosetting resin film or protective film is cut to the size of the semiconductor chip, thereby covering not only the bump-formed surface of the semiconductor chip but also its side. Figure 9 shows a semiconductor chip with a protective film on not only the bump-formed surface but also its side. Figure 9 is a cross-sectional view showing a schematic example of a semiconductor chip (semiconductor chip with protective film) having a protective film on the bump-forming surface and side surfaces, assuming that it can be obtained normally when using the above-mentioned protective film forming sheet 8.

The semiconductor chip 909 with a protective film shown here comprises a semiconductor chip 9' and a first protective film 820' provided on the side surface 9c' and bump-forming surface 9a' of the semiconductor chip 9'. The semiconductor chip 9' is protected by the first protective film 820' after cutting on its side surface 9c' and bump-forming surface 9a', respectively, and the protective effect obtained by the semiconductor chip 9' is significantly high.

In the manufacturing process for such multi-sided protected semiconductor chips, which have protective films on the bump-forming surface and side surfaces of the semiconductor chip, when the thermosetting resin film in the protective film forming sheet is bonded, it is necessary to thoroughly fill the grooves with the thermosetting resin film. However, the shape of the grooves is very fine (e.g., 20 μm wide, 200 μm deep), making it very difficult to fill the thermosetting resin film. In addition, during the process of forming the grooves using a blade carrying abrasive grains, the sides of the grooves are not smooth and have tiny cutting marks due to the abrasive grains of the blade.

When a thermosetting resin film is applied to the bump-forming surface of a semiconductor wafer and the uneven surface including the grooves, if the thermosetting resin film does not sufficiently fill the fine grooves on the uneven surface and also does not adhere sufficiently to the tiny cutting marks on the sides of the grooves, the protective film may peel off from the uneven surface.

The present invention aims to provide a thermosetting resin film that can be applied to an uneven surface and can form a protective film, which can sufficiently fill fine grooves on the uneven surface and prevent the protective film from peeling off from the uneven surface, a composite sheet including the thermosetting resin film, and a method for manufacturing a semiconductor chip with a first protective film.

As a result of intensive research aimed at solving the above-mentioned problems, the present inventors have noticed that in order for a thermosetting resin film to infiltrate and adhere to the cutting marks on the side surfaces of the grooves, not only the melting behavior of the thermosetting resin film when it is applied but also its behavior when it is thermally cured is important. The present inventors have found that when the gelation time of the thermosetting resin film at 180°C is 300 seconds or more, the thermosetting resin film can sufficiently infiltrate and adhere to the minute cutting marks on the side surfaces of the grooves that were not completely filled during application, and can thereby suppress peeling of the protective film from the uneven surface, thereby completing the present invention.
That is, the present invention has the following aspects.

[1] A thermosetting resin film,
A thermosetting resin film having a size of 10 mm x 10 mm x 1 mm is used as a first test piece, and when the first test piece is placed on a stainless steel plate heated to 180°C in a recessed sample holder of an automatic curing time measuring device "Madoka," and heated and stirred under the following conditions, the gelation time is 300 seconds or more from the time when the torque of the stirring blade reaches 2.5 gf cm.
(Conditions for heating and stirring)
・Stirring blade: screw stirring rod ・Stirring blade model number: 5TC-72890
Rotation speed of stirring blade: 100 rpm
Rotation speed of stirring blade: 40 rpm
Distance between heated stainless steel plate and stirring blade: 0.3 mm
・Stainless steel plate heating setting temperature: 180℃

[2] A thermosetting resin film having a diameter of 25 mm and a thickness of 1 mm was used as a second test piece, and strain was generated in the second test piece under conditions of a temperature of 90°C and a frequency of 1 Hz to measure the storage elastic modulus of the second test piece. When the storage elastic modulus of the second test piece when the strain of the second test piece is 1% is defined as Gc1, and the storage elastic modulus of the second test piece when the strain of the second test piece is 300% is defined as Gc300, the following formula is obtained:
X=Gc1/Gc300
The thermosetting resin film according to [1], wherein the X value calculated by the above formula is 19 or more and less than 10,000.
[3] The thermosetting resin film according to [1] or [2], wherein the thermosetting resin film is for application to an uneven surface.
[4] The thermosetting resin film according to any one of [1] to [3], wherein the thermosetting resin film is for protecting the uneven surface and side surfaces of a semiconductor chip.

[5] A support sheet and a resin film provided on one surface of the support sheet,
The resin film is the thermosetting resin film according to any one of [1] to [4].
[6] The composite sheet described in [5], wherein the support sheet comprises a substrate and an adhesive layer provided on one side of the substrate, and the adhesive layer is disposed between the substrate and the resin film.
[7] The composite sheet described in [5], wherein the support sheet comprises a substrate and a buffer layer provided on one side of the substrate, and the buffer layer is disposed between the substrate and the thermosetting resin film.

[8] A method for manufacturing a semiconductor chip with a first protective film using a semiconductor wafer, comprising:
The semiconductor chip with a first protective film includes a semiconductor chip and a first protective film provided on a side surface of the semiconductor chip and a surface having bumps,
the semiconductor wafer has, on one surface thereof, bumps and grooves that become dividing portions of the semiconductor wafer;
The manufacturing method includes a bonding step of bonding the thermosetting resin film in the composite sheet according to any one of [5] to [7] to the one surface of the semiconductor wafer, thereby producing a semiconductor wafer with a thermosetting resin film, in which the one surface is provided with the thermosetting resin film and the grooves are filled with the thermosetting resin film;
The manufacturing method further comprises:
a curing step (1) of, after the attaching step, thermally curing the thermosetting resin film to form the first protective film, thereby producing a semiconductor wafer with a first protective film, the semiconductor wafer including the semiconductor wafer and the first protective film provided on the one surface of the semiconductor wafer and filling the grooves; a dividing step (1) of, after the curing step (1), dividing the semiconductor wafer to produce a group of semiconductor chips with a first protective film, the group including a plurality of semiconductor chips and the first protective film provided on surfaces of the plurality of semiconductor chips having the bumps and in gaps between the semiconductor chips; and a cutting step (1) of, after the dividing step (1), cutting the first protective film along the gaps between the semiconductor chips in the group of semiconductor chips with a first protective film, thereby producing the semiconductor chips with a first protective film;
a cutting step (2) of cutting the first protective film along the grooves in the semiconductor wafer with the first protective film after the bonding step and the curing step (1) to produce a cut-in semiconductor wafer with the first protective film, and a dividing step (2) of dividing the semiconductor wafer after the cutting step (2) to produce semiconductor chips with the first protective film, or
a dividing step (3) of dividing the semiconductor wafer after the bonding step to produce a group of semiconductor chips with a thermosetting resin film, the group including a plurality of semiconductor chips and the thermosetting resin film provided on the surfaces of the plurality of semiconductor chips having the bumps and in the gaps between the semiconductor chips; a curing step (3) of thermally curing the thermosetting resin film after the dividing step (3) to form the first protective film, thereby producing a group of semiconductor chips with a first protective film, the group including a plurality of semiconductor chips and the first protective film provided on the surfaces of the plurality of semiconductor chips having the bumps and in the gaps between the semiconductor chips; and a cutting step (3) of cutting the first protective film along the gaps between the semiconductor chips in the group of semiconductor chips with a first protective film after the curing step (3), to obtain the semiconductor chips with a first protective film.

The present invention provides a thermosetting resin film that can be applied to an uneven surface and can form a protective film, which can sufficiently fill fine grooves on the uneven surface and prevent the protective film from peeling off from the uneven surface; a composite sheet including the thermosetting resin film; and a method for manufacturing a semiconductor chip with a first protective film.

1 is a cross-sectional view schematically illustrating an example of a thermosetting resin film according to one embodiment of the present invention. FIG. 10 is a plan view for schematically explaining the amount of protrusion of a thermosetting resin film when the planar shape of the thermosetting resin film is circular. 1 is a cross-sectional view schematically illustrating an example of a composite sheet according to an embodiment of the present invention. 4A to 4C are cross-sectional views schematically showing an example of a method for manufacturing a semiconductor chip with a first protective film when the composite sheet shown in FIG. 3 is used. 4A to 4C are cross-sectional views schematically showing an example of a method for manufacturing a semiconductor chip with a first protective film when the composite sheet shown in FIG. 3 is used. 4A to 4C are cross-sectional views schematically showing an example of a method for manufacturing a semiconductor chip with a first protective film when the composite sheet shown in FIG. 3 is used. 4A to 4C are cross-sectional views schematically showing an example of a method for manufacturing a semiconductor chip with a first protective film when the composite sheet shown in FIG. 3 is used. 4A to 4C are cross-sectional views schematically showing an example of a method for manufacturing a semiconductor chip with a first protective film when the composite sheet shown in FIG. 3 is used. 4A to 4C are cross-sectional views schematically showing another example of a method for manufacturing a semiconductor chip with a first protective film when the composite sheet shown in FIG. 3 is used. 4A to 4C are cross-sectional views schematically showing another example of a method for manufacturing a semiconductor chip with a first protective film when the composite sheet shown in FIG. 3 is used. 4A to 4C are cross-sectional views schematically showing another example of a method for manufacturing a semiconductor chip with a first protective film when the composite sheet shown in FIG. 3 is used. 4A to 4C are cross-sectional views schematically showing another example of a method for manufacturing a semiconductor chip with a first protective film when the composite sheet shown in FIG. 3 is used. 4A to 4C are cross-sectional views schematically showing another example of a method for manufacturing a semiconductor chip with a first protective film when the composite sheet shown in FIG. 3 is used. 10 is a cross-sectional view schematically showing yet another example of a method for manufacturing a semiconductor chip with a first protective film when the composite sheet shown in FIG. 3 is used. FIG. 10 is a cross-sectional view schematically showing yet another example of a method for manufacturing a semiconductor chip with a first protective film when the composite sheet shown in FIG. 3 is used. FIG. 10 is a cross-sectional view schematically showing yet another example of a method for manufacturing a semiconductor chip with a first protective film when the composite sheet shown in FIG. 3 is used. FIG. 10 is a cross-sectional view schematically showing yet another example of a method for manufacturing a semiconductor chip with a first protective film when the composite sheet shown in FIG. 3 is used. FIG. 10 is a cross-sectional view schematically showing yet another example of a method for manufacturing a semiconductor chip with a first protective film when the composite sheet shown in FIG. 3 is used. FIG. FIG. 2 is a plan view schematically showing a laminate including a thermosetting resin film produced when measuring the amount of protrusion of the thermosetting resin film in Example 1. 1A to 1C are cross-sectional views for schematically explaining a method for forming a protective film on a bump-formed surface of a semiconductor wafer. 1A to 1C are cross-sectional views for schematically explaining a method for forming a protective film on a bump-formed surface of a semiconductor wafer. 1A to 1C are cross-sectional views for schematically explaining a method for forming a protective film on a bump-formed surface of a semiconductor wafer. 1A to 1C are cross-sectional views for schematically explaining a method for forming a protective film on a bump-formed surface of a semiconductor wafer. 1 is a cross-sectional view schematically showing an example of a semiconductor chip having a protective film on a bump-forming surface and a side surface.

Thermosetting resin film and method for manufacturing the same In the thermosetting resin film according to an embodiment of the present invention, a first test piece of the thermosetting resin film having a size of 10 mm x 10 mm x 1 mm is used, and when the first test piece is placed on a stainless steel plate heated to 180°C in a recessed sample holder of the automatic curing time measuring device "Madoka," and heated and stirred under the following conditions, the gelation time is 300 seconds or more from the time when the torque of the stirring blade reaches 2.5 gf cm.
(Conditions for heating and stirring)
・Stirring blade: screw stirring rod ・Stirring blade model number: 5TC-72890
Rotation speed of stirring blade: 100 rpm
Rotation speed of stirring blade: 40 rpm
Distance between heated stainless steel plate and stirring blade: 0.3 mm
・Heating setting temperature: 180℃

[Measurement of gel time of thermosetting resin film]
The gel time of the thermosetting resin film can be measured using an automatic curing time measuring device "Madoka" (manufactured by Cyber Corporation, model number: MDK4G-02SP) as follows.

A 10mm x 10mm x 1mm piece of the thermosetting resin film was used as the first test piece. The first test piece was placed on a stainless steel plate heated to 180°C in the recessed sample holder of the Madoka automatic curing time measuring device (manufactured by Cyber Corporation). The first test piece placed on the 180°C stainless steel plate quickly liquefied. At this time, the stirring blade installed at a distance above the stainless steel plate was rotating. Over 15 seconds, the heated stainless steel plate was raised to a position where the distance between the stainless steel plate and the stirring blade was 0.3 mm, so that the stirring blade came into contact with the thermosetting resin that had liquefied from the thermosetting resin film. The stirring blade was rotated under the heating and stirring conditions, and the thermosetting resin was continuously stirred while measuring the stirring blade torque. The gelation time was measured as the time (s) from when the first test piece was placed on the stainless steel plate to when the stirring blade torque reached 2.5 gf·cm.

The thermosetting resin film of this embodiment is suitable for application to uneven surfaces. Furthermore, the thermosetting resin film of this embodiment can form a protective film by thermal curing. The resin film of this embodiment is suitable for protecting the uneven surfaces and side surfaces of semiconductor chips.

When the thermosetting resin film of this embodiment is applied to an uneven surface while being heated, the softened thermosetting resin film spreads between the convex portions, covering the convex portions and adhering to the uneven surface. It also covers the surface of the convex portions, particularly the surface in the vicinity of the convex portions, embedding the bases of the convex portions. Furthermore, if the uneven surface has fine grooves, the thermosetting resin film can sufficiently fill these grooves. Even if the sides of the grooves have minute cutting marks, the protective film can be adhered to the cutting marks on the sides of the grooves, preventing peeling of the protective film. The reason why the thermosetting resin film and protective film can sufficiently fill the grooves, adhere to the cutting marks on the sides of the grooves, and prevent peeling of the protective film is that the gelation time of the thermosetting resin film at 180°C is 300 seconds or longer.

At a given curing temperature, the thermosetting resin film melts once, and then the thermosetting reaction progresses to form a protective film. When molten, the thermosetting resin has the lowest viscosity and highest mobility, making it the ideal state for filling tiny spaces. By remaining in this molten state for a long time, even if air bubbles remain inside the groove when the thermosetting resin film is applied, or if the thermosetting resin does not adhere sufficiently to the cutting marks on the side of the groove, the air bubbles inside the groove are removed during thermal curing, allowing the protective film to adhere to the cutting marks on the side of the groove.

Furthermore, according to the inventors' studies, when the gelation time of the thermosetting resin film at 180°C is 300 seconds or more, it can sufficiently infiltrate and adhere to the minute cutting marks on the side surfaces of the grooves that were not completely filled during application, thereby preventing peeling of the protective film from the uneven surface. Regardless of the appropriate curing temperature of the thermosetting resin film, a correlation was observed between the gelation time at 180°C and the effect of preventing peeling of the protective film. When the gelation time of the thermosetting resin film at 180°C is 300 seconds or more, it can sufficiently infiltrate and adhere to the minute cutting marks on the side surfaces of the grooves, preventing peeling of the protective film from the uneven surface. In contrast, when the gelation time of the thermosetting resin film at 180°C is less than 300 seconds, it does not adequately adhere to the minute cutting marks on the side surfaces of the grooves, which can easily cause the protective film to peel from the uneven surface in subsequent processes, starting from the minute cutting marks on the side surfaces of the grooves.

The gel time of the thermosetting resin film at 180°C is 300 seconds or more, preferably 310 seconds or more, more preferably 320 seconds or more, even more preferably 330 seconds or more, and particularly preferably 340 seconds or more. The gel time of the thermosetting resin film at 180°C is preferably 3000 seconds or less, preferably 1500 seconds or less, and even more preferably 1000 seconds or less. A longer gel time can further improve adhesion to cutting marks.

When applying the thermosetting resin film of this embodiment to an uneven surface, the heating temperature and application pressure of the thermosetting resin film can be adjusted appropriately depending on other application conditions and the width and depth of the grooves on the uneven surface, but can be the same as when applying it to the bump-forming surface of a semiconductor wafer, as described below.

The degree to which the thermosetting resin film or protective film fills the grooves on the uneven surface (sometimes referred to in this specification as "groove filling suitability") can be confirmed by observing the uneven surface provided with the thermosetting resin film or protective film using an optical microscope.
The degree to which peeling of the protective film from the uneven surface is suppressed can be confirmed by observing the uneven surface provided with the protective film using an optical microscope.

When applying the thermosetting resin film of this embodiment to an uneven surface, a composite sheet including the thermosetting resin film of this embodiment can be used. Composite sheets will be described in more detail later.

More specifically, examples of objects to which the thermosetting resin film having the uneven surface can be attached include semiconductor wafers having bumps.
That is, the thermosetting resin film can be attached to a semiconductor wafer before it is divided into semiconductor chips. In this case, the thermosetting resin film is attached to the surface of the semiconductor wafer having bumps.

In this specification, the surface of a semiconductor wafer or semiconductor chip that has bumps may be referred to as the "bump-forming surface."

By applying the thermosetting resin film to the bump-forming surface while heating it, the softened thermosetting resin film spreads between the bumps, covering them and adhering closely to the bump-forming surface. It also covers the bump surfaces, particularly the surfaces near the bump-forming surface, and embeds the bases of the bumps. In this case, the bumps on the bump-forming surface preferably penetrate the thermosetting resin film, with the tops of the bumps protruding from the thermosetting resin film. Furthermore, if the bump-forming surface has fine grooves, the thermosetting resin film can sufficiently fill these grooves, thereby allowing the protective film to sufficiently fill the grooves. Furthermore, peeling of the protective film from the uneven surface can be suppressed. The reasons for these effects are as described above.

The thermosetting resin film that is applied to the bump formation surface and filled into the grooves is then left in this state to harden and ultimately form the first protective film.

In this specification, the protective film provided on the bump-formed surface of a semiconductor wafer or semiconductor chip is referred to as the "first protective film." The protective film provided on the surface opposite the bump-formed surface of a semiconductor wafer or semiconductor chip (i.e., the back surface) is referred to as the "second protective film."

The thicknesses of the multiple single-layer thermosetting resin films (in other words, the cured products of the multiple single-layer thermosetting resin films) that make up the laminate film may all be the same, all different, or only some of them may be the same, but for ease of production, it is preferable that they all be the same.

In this embodiment, the thermosetting resin film having a diameter of 25 mm and a thickness of 1 mm is used as a second test piece, and strain is generated in the second test piece under conditions of a temperature of 90°C and a frequency of 1 Hz to measure the storage elastic modulus of the second test piece. When the storage elastic modulus of the second test piece when the strain of the second test piece is 1% is defined as Gc1, and the storage elastic modulus of the second test piece when the strain of the second test piece is 300% is defined as Gc300, the following formula is obtained:
X=Gc1/Gc300
It is preferable that the X value calculated by the above formula is 19 or more and less than 10,000 (19≦X value<10,000).

When such a thermosetting resin film is applied to an uneven surface, the convex portions of the uneven surface penetrate the thermosetting resin film, causing the upper portions of the convex portions to protrude from the thermosetting resin film. At this time, the thermosetting resin film is prevented from remaining at the upper portions of the convex portions. Naturally, the cured product of the thermosetting resin film in this state is also prevented from adhering to the upper portions of the convex portions. Furthermore, since the thermosetting resin film after application is prevented from protruding from its original size, for example, protrusion of the thermosetting resin film from the uneven surface is prevented. Furthermore, when the thermosetting resin film and its cured product are applied to the uneven surface, regions of the convex portions of the uneven surface other than the upper portions (e.g., base portions near the uneven surface) or regions near the convex portions of the uneven surface are prevented from being unintentionally exposed without being covered by the thermosetting resin film and its cured product, a phenomenon known as repelling.
When the X value is 19 or more and less than 10,000, the thermosetting resin film has superior properties in that the entire uneven surface can be covered with the thermosetting resin film itself and its cured product while exposing the convex portions.

The second test piece for measuring strain dispersion is in the form of a film, and its planar shape is circular.
The second test piece may be a single layer of the thermosetting resin film having a thickness of 1 mm, but in terms of ease of preparation, it is preferable that the second test piece be a laminated film composed of multiple single layers of the thermosetting resin film having a thickness of less than 1 mm.
The thicknesses of the multiple single-layer thermosetting resin films that make up the laminated film may all be the same, all different, or only some of them may be the same, but from the viewpoint of ease of production, it is preferable that they are all the same.

In this specification, the term "storage modulus of the second test piece" is not limited to Gc1 and Gc300 and means "the storage modulus of the second test piece corresponding to the strain generated when strain is generated in the second test piece of thermosetting resin film having a diameter of 25 mm and a thickness of 1 mm under the conditions of a temperature of 90°C and a frequency of 1 Hz."

When a thermosetting resin film is applied to the uneven surface of an object, the degree of distortion of the thermosetting resin film differs significantly between the middle stage when the tops of the convex portions of the uneven surface (the tops of the bumps if the object is a semiconductor wafer with bumps) penetrate and protrude through the thermosetting resin film, and the final stage when the bases of the convex portions are embedded in the thermosetting resin film after the tops of the convex portions have penetrated and protruded through the thermosetting resin film. More specifically, the distortion of the thermosetting resin film is large in the middle stage and small in the final stage.
The thermosetting resin film of this embodiment employs Gc1 as the storage modulus when the strain is small and Gc300 as the storage modulus when the strain is large, and by setting the X value (= Gc1/Gc300) to a specific range such that Gc1 is high and Gc300 is low, the excellent effects described above are achieved.

The presence or absence of the thermosetting resin film remaining on the tops of the convex portions of the textured surface can be confirmed, for example, by obtaining SEM image data of the tops of the convex portions.
In addition, whether or not the thermosetting resin film is protruding from the uneven surface and whether or not the thermosetting resin film is repelling from the uneven surface can be confirmed, for example, by obtaining SEM image data of the relevant area on the uneven surface.

In the thermosetting resin film, the X value may be, for example, any one of 5000 or less, 2000 or less, 1000 or less, 500 or less, 300 or less, 100 or less, and 70 or less.
For example, the X value may be any of 19 to 5000, 25 to 2000, 30 to 1000, 35 to 500, 40 to 300, 45 to 100, and 50 to 70.

When other thermosetting resin films with an X value of 10,000 or more are applied to an uneven surface, even if the tops of the convex portions protrude from the other thermosetting resin film, no effect of suppressing repelling is observed, and the cured product of the other thermosetting resin film will remain in a state where repelling occurs.

In the thermosetting resin film, when the film is attached to an uneven surface, the film can penetrate the convex portions and can be prevented from remaining on the upper portions of the convex portions. Therefore, it is preferable that the X value of Gc1 is 19 or more and less than 10,000.
However, as explained above, in order to achieve a high level of the effects of suppressing the thermosetting resin film from remaining at the top of the convex portions, the effects of suppressing the thermosetting resin film from protruding, and the effects of suppressing the thermosetting resin film and its cured product from cissing, Gc1 is preferably 1×10 ⁴ to 1×10 ⁶ Pa, and more preferably 1×10 ⁵ to 7×10 ⁵ Pa.

In the thermosetting resin film, Gc300 is not particularly limited as long as the X value is 19 or more and less than 10,000.
However, for the same reasons as in the case of Gc1 above, Gc300 is preferably 1 to 30,000 Pa, and may be, for example, 1 to 5,000 Pa or 5,000 to 30,000 Pa.

The thermosetting resin film preferably satisfies both of the above conditions, that is, Gc1 is 1×10 ⁴ to 1×10 ⁶ Pa, preferably 1×10 ⁵ to 7×10 ⁵ Pa, and Gc300 is 1 to 30,000 Pa, 1 to 5,000 Pa, or 5,000 to 30,000 Pa.

The storage modulus of the thermosetting resin film can be easily adjusted by adjusting the type or content of the components contained in the thermosetting resin film, not limited to Gc1 and Gc300. To achieve this, the type or content of the components contained in the composition for forming the thermosetting resin film can be adjusted. For example, when using the thermosetting resin film-forming composition (III) described below, the storage modulus of the thermosetting resin film can be easily adjusted by adjusting the type or content of the main components contained in the composition, such as the polymer component (A) and the filler (D), or by adjusting the type or content of the additive (I), such as a rheology control agent, a surfactant, or a silicone oil.
For example, when the content of the filler (D) or the additive (I) in the thermosetting resin film and the composition (III) is increased, the value of X tends to increase.

The thermosetting resin film of this embodiment can be laminated with a support sheet, for example, as described below, to form a composite sheet.

FIG. 1 is a cross-sectional view schematically illustrating an example of a thermosetting resin film according to one embodiment of the present invention.
In addition, the figures used in the following explanation may show enlarged essential parts for the sake of convenience in order to make the features of the present invention easier to understand, and the dimensional ratios of each component may not necessarily be the same as in reality.

The thermosetting resin film 12 shown here has a first release film 151 on one of its surfaces (sometimes referred to as the "first surface" in this specification) 12a, and a second release film 152 on the other surface (sometimes referred to as the "second surface" in this specification) 12b opposite the first surface 12a.
Such a thermosetting resin film 12 is suitable for storage, for example, in a roll form.

It is preferable that the X value of the second test piece of the thermosetting resin film 12 is greater than or equal to 19 and less than 10,000.

The first release film 151 and the second release film 152 may both be of known types.
The first release film 151 and the second release film 152 may be the same as each other, or may be different from each other, for example, in that they require different peeling forces when peeling from the thermosetting resin film 12.

When either the first release film 151 or the second release film 152 is removed from the thermosetting resin film 12 shown in Figure 1, the resulting exposed surface becomes the surface to be attached to the uneven surface. Then, when the other remaining first release film 151 or second release film 152 is removed, the resulting exposed surface becomes the surface to be attached to other layers (e.g., a buffer layer, an adhesive layer, etc.) that will form the composite sheet described below.

Figure 1 shows an example in which a release film is provided on both sides (first side 12a, second side 12b) of the thermosetting resin film 12, but the release film may be provided on only one side of the thermosetting resin film 12, i.e., only the first side 12a or only the second side 12b.

The thermosetting resin film of the present embodiment contains a resin component, and may or may not contain components other than the resin component.
Preferred examples of thermosetting resin films include those containing a resin component, a thermosetting component, and a filler, and optionally various additives that do not fall into any of these categories (resin component, thermosetting component, and filler) and have the effect of adjusting the storage modulus of the thermosetting resin film.

Examples of additives that have the effect of adjusting the storage modulus of the thermosetting resin film include rheology control agents (thixotropic agents), surfactants, silicone oils, etc.

If a thermosetting resin film protrudes from its original size when applied to an object, such as when applied to an uneven surface, the protruding thermosetting resin film can be viewed in a planar view from above, and the maximum length of the line segment connecting two different points on the outer circumference of the thermosetting resin film can be found. Furthermore, the original width of the thermosetting resin film (i.e., before it protruded) at the position where it overlaps with the line segment indicating this maximum length can be found. The amount of protrusion of the thermosetting resin film can be calculated by subtracting the width of the thermosetting resin film from the maximum length of the line segment.

FIG. 2 is a plan view for schematically explaining the amount of protrusion of a thermosetting resin film when the planar shape of the thermosetting resin film is circular.
In FIG. 2 and subsequent figures, the same components as those shown in the figures already described are given the same reference numerals as in the figures already described, and detailed description thereof will be omitted.

The thermosetting resin film 101 shown here protrudes from its original size when attached to the attachment object 102. The reference symbol 101' indicates the thermosetting resin film at its original size, and is shown for convenience to make it easier to understand the amount of protrusion. The planar shape of the original thermosetting resin film 101' is circular here, but the planar shape of the protruding thermosetting resin film 101 is non-circular. However, this is just one example, and the planar shape of the protruding thermosetting resin film 101 is not limited to that shown here.

To determine the amount of protrusion of the thermosetting resin film 101, the maximum value of the length D1 of the line segment connecting one point 1010a on the outer periphery 1010 of the thermosetting resin film 101 and another point 1010b is determined, and then the value _D0 of the initial width (i.e., before protrusion) of the thermosetting resin film 101' at the position where the length _D1 overlaps with the line segment indicating this maximum value is determined. The difference between _D1 and _D0 ( _D1 - _D0 ) is the amount of protrusion.
The line segment indicating the maximum value in the thermosetting resin film 101 may pass through the center of the circle in the initial thermosetting resin film 101' when viewed in a plane, and in that case, the width value of the initial thermosetting resin film 101' at the position where it overlaps with the line segment indicating this maximum value becomes the diameter of the thermosetting resin film 101'.

Here, we have explained the amount of overhang of a thermosetting resin film when the planar shape of the thermosetting resin film is circular, with reference to the drawings. However, the amount of overhang of a thermosetting resin film can also be calculated in a similar manner when the planar shape is other than circular.

The thermosetting resin film may consist of one layer (single layer) or two or more layers. When the thermosetting resin film consists of multiple layers, these layers may be the same or different, and the combination of these layers is not particularly limited.

In this specification, not only in the case of the thermosetting resin film, "multiple layers may be the same or different" means "all layers may be the same, all layers may be different, or only some layers may be the same," and further, "multiple layers are different" means "at least one of the constituent materials and thicknesses of each layer is different from each other."

The thickness of the thermosetting resin film is preferably 1 to 100 μm, more preferably 5 to 80 μm, and particularly preferably 5 to 60 μm. When the thickness of the thermosetting resin film is equal to or greater than the lower limit, the effect of the thermosetting resin film is enhanced. For example, when a protective film is formed using a thermosetting resin film, a protective film with higher protective ability can be formed. On the other hand, when the thickness of the thermosetting resin film is equal to or less than the upper limit, excessive thickness is prevented.
Here, the "thickness of the thermosetting resin film" means the thickness of the entire thermosetting resin film. For example, the thickness of a thermosetting resin film consisting of multiple layers means the total thickness of all layers that make up the thermosetting resin film.
In this specification, unless otherwise specified, "thickness" refers to a value expressed as the average of thickness measurements at five randomly selected locations, and can be obtained using a constant pressure thickness gauge in accordance with JIS K7130.

<<Thermosetting resin film-forming composition>>
The thermosetting resin film can be formed using a composition for forming a thermosetting resin film containing its constituent materials. For example, the thermosetting resin film can be formed by applying the composition for forming a thermosetting resin film to the surface to be formed and drying it as necessary. The ratio of the contents of the components that do not vaporize at room temperature in the composition for forming a thermosetting resin film is usually the same as the ratio of the contents of the components in the thermosetting resin film.
In this specification, "room temperature" means a temperature that is neither particularly cold nor hot, that is, an ordinary temperature, and examples thereof include temperatures of 15 to 25°C.

Thermosetting resin films can be formed using a composition for forming thermosetting resin films. Note that, in this specification, a thermosetting resin film may have both thermosetting and energy ray-curing properties.

The thermosetting resin film-forming composition can be applied by known methods, such as using various coaters such as an air knife coater, blade coater, bar coater, gravure coater, roll coater, roll knife coater, curtain coater, die coater, knife coater, screen coater, Meyer bar coater, and kiss coater.

The drying conditions for the thermosetting resin film-forming composition are not particularly limited. However, if the thermosetting resin film-forming composition contains a solvent, as described below, it is preferable to heat-dry it. Furthermore, a thermosetting resin film-forming composition containing a solvent is preferably heat-dried, for example, at 70 to 130°C for 10 seconds to 5 minutes. However, it is preferable to heat-dry a thermosetting resin film-forming composition so that the composition itself and the thermosetting resin film formed from this composition are not thermally cured.

Thermosetting resin films are described in more detail below.

Thermosetting Resin Film When a thermosetting resin film is cured to form a cured product, particularly when a protective film is formed, the curing conditions are not particularly limited as long as the cured product has a degree of curing that allows it to fully exhibit its functions. The curing conditions may be appropriately selected depending on the type of thermosetting resin film, the application of the cured product, etc.

For example, when forming a protective film, the heating temperature during curing of the thermosetting resin film is preferably 100 to 200°C, more preferably 110 to 170°C, and particularly preferably 120 to 150°C. The heating time during thermal curing is preferably 0.5 to 5 hours, more preferably 0.5 to 4 hours, and particularly preferably 1 to 4 hours. The thermosetting resin film may be cured while being pressurized, in which case the pressure applied is preferably 0.1 to 1 MPa.

<Thermosetting Resin Film-Forming Composition>
Examples of the composition for forming a thermosetting resin film include a composition for forming a thermosetting resin film (III) (sometimes simply referred to as "composition (III)" in this specification) containing a polymer component (A), a thermosetting component (B), and a filler (D).

[Polymer component (A)]
The polymer component (A) is a polymer compound for imparting film-forming properties, flexibility, etc. to the thermosetting resin film. In this specification, the polymer compound also includes products of polycondensation reactions.
The polymer component (A) contained in the composition (III) and the thermosetting resin film may be one type or two or more types, and when two or more types are contained, the combination and ratio thereof can be selected arbitrarily.

Examples of the polymer component (A) include polyvinyl acetal, acrylic resin, urethane resin, phenoxy resin, silicone resin, saturated polyester resin, and the like.
Among these, the polymer component (A) is preferably polyvinyl acetal.

The polyvinyl acetal in the polymer component (A) may be any known polyvinyl acetal.
Of these, preferred polyvinyl acetals include, for example, polyvinyl formal and polyvinyl butyral, with polyvinyl butyral being more preferred.
Examples of polyvinyl butyral include those having structural units represented by the following formulas (i)-1, (i)-2 and (i)-3.

(In the formula, l, m, and n each independently represent an integer of 1 or more.)

The weight-average molecular weight (Mw) of the polyvinyl acetal is preferably 5,000 to 200,000, and more preferably 8,000 to 100,000. Having a weight-average molecular weight of polyvinyl acetal in this range results in the effect of sufficiently filling the fine grooves on the uneven surface when a thermosetting resin film is applied to the uneven surface, thereby preventing peeling of the protective film from the uneven surface (for example, the effect of sufficiently filling the fine grooves on the bump-forming surface when a thermosetting resin film is applied to the bump-forming surface, thereby preventing peeling of the protective film from the bump-forming surface; the same applies below). Also, the effect of preventing the thermosetting resin film from remaining on the upper parts of the convex portions of the uneven surface when a thermosetting resin film is applied to the bump-forming surface (for example, the effect of preventing the thermosetting resin film from remaining on the upper parts of the bumps when a thermosetting resin film is applied to the bump-forming surface) The effect of suppressing the thermosetting resin film from remaining on the uneven surface (for example, the effect of suppressing the thermosetting resin film from protruding from its original size on the bump-forming surface when the thermosetting resin film is attached to the bump-forming surface; the same applies below), and the effect of suppressing the thermosetting resin film and its cured product from repelling on the uneven surface (for example, the effect of suppressing the thermosetting resin film and its cured product from repelling on the bump-forming surface when the thermosetting resin film is attached to the bump-forming surface; the same applies below) are further enhanced.

In this specification, unless otherwise specified, "weight average molecular weight" refers to a polystyrene-equivalent value measured by gel permeation chromatography (GPC).

The glass transition temperature (Tg) of the polyvinyl acetal is preferably 40 to 80°C, and more preferably 50 to 70°C. Having a Tg of polyvinyl acetal in this range ensures that when a thermosetting resin film is applied to the uneven surface, it sufficiently fills the fine grooves on the uneven surface, thereby enhancing the effects of preventing peeling of the protective film from the uneven surface, preventing the thermosetting resin film from remaining on the tops of the convex portions of the uneven surface, preventing the thermosetting resin film from spilling over the uneven surface, and preventing repelling of the thermosetting resin film and its cured product on the uneven surface.

The ratio of the three or more monomers that make up the polyvinyl acetal can be selected arbitrarily.

The acrylic resin in the polymer component (A) may be any known acrylic polymer.
The weight-average molecular weight (Mw) of the acrylic resin is preferably 5,000 to 1,000,000, and more preferably 8,000 to 800,000. When the weight-average molecular weight of the acrylic resin is within this range, when the thermosetting resin film is attached to the uneven surface, the fine grooves on the uneven surface are sufficiently filled, and the effects of suppressing peeling of the protective film from the uneven surface, suppressing the thermosetting resin film from remaining on the upper parts of the convex portions of the uneven surface, suppressing protrusion of the thermosetting resin film from the uneven surface, and suppressing repelling of the thermosetting resin film and its cured product on the uneven surface are enhanced.

The glass transition temperature (Tg) of the acrylic resin is preferably -50 to 70°C, and more preferably -30 to 60°C. Having an acrylic resin Tg within this range ensures that when a thermosetting resin film is applied to the uneven surface, it sufficiently fills the fine grooves on the uneven surface, thereby enhancing the effects of preventing peeling of the protective film from the uneven surface, preventing the thermosetting resin film from remaining on the tops of the convex portions of the uneven surface, preventing the thermosetting resin film from spilling over the uneven surface, and preventing repelling of the thermosetting resin film and its cured product on the uneven surface.

When an acrylic resin has two or more structural units, the glass transition temperature (Tg) of the acrylic resin can be calculated using the Fox equation. The Tg of the monomer from which the structural units are derived can be calculated using the values listed in the Polymer Data Handbook or the Adhesive Handbook.

The monomers constituting the acrylic resin may be of one type only, or of two or more types, and if there are two or more types, the combination and ratio thereof can be selected arbitrarily.

Examples of acrylic resins include polymers of one or more (meth)acrylic acid esters;
A copolymer of two or more monomers selected from (meth)acrylic acid, itaconic acid, vinyl acetate, acrylonitrile, styrene, N-methylolacrylamide, and the like;
Examples include copolymers of one or more (meth)acrylic acid esters with one or more monomers selected from (meth)acrylic acid, itaconic acid, vinyl acetate, acrylonitrile, styrene, N-methylolacrylamide, and the like.

In this specification, the term "(meth)acrylic acid" encompasses both "acrylic acid" and "methacrylic acid." The same applies to terms similar to (meth)acrylic acid; for example, "(meth)acrylate" encompasses both "acrylate" and "methacrylate," and "(meth)acryloyl group" encompasses both "acryloyl group" and "methacryloyl group."

Examples of the (meth)acrylic acid ester constituting the acrylic resin include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, p) (meth)acrylic acid alkyl esters in which the alkyl group constituting the alkyl ester has a chain structure and has 1 to 18 carbon atoms, such as isononyl acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate (lauryl (meth)acrylate), tridecyl (meth)acrylate, tetradecyl (meth)acrylate (myristyl (meth)acrylate), pentadecyl (meth)acrylate, hexadecyl (meth)acrylate (palmityl (meth)acrylate), heptadecyl (meth)acrylate, and octadecyl (meth)acrylate (stearyl (meth)acrylate);
(meth)acrylic acid cycloalkyl esters such as isobornyl (meth)acrylate and dicyclopentanyl (meth)acrylate;
(Meth)acrylic acid aralkyl esters such as benzyl (meth)acrylate;
(Meth)acrylic acid cycloalkenyl esters such as (meth)acrylic acid dicyclopentenyl ester;
(Meth)acrylic acid cycloalkenyloxyalkyl esters such as (meth)acrylic acid dicyclopentenyloxyethyl ester;
(Meth)acrylic acid imide;
glycidyl group-containing (meth)acrylic acid esters such as glycidyl (meth)acrylate;
hydroxyl group-containing (meth)acrylic acid esters such as hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate;
Examples include substituted amino group-containing (meth)acrylic acid esters such as N-methylaminoethyl (meth)acrylate. Here, the term "substituted amino group" refers to a group in which one or two hydrogen atoms of an amino group are substituted with a group other than a hydrogen atom.

The acrylic resin may have functional groups capable of bonding with other compounds, such as vinyl groups, (meth)acryloyl groups, amino groups, hydroxyl groups, carboxy groups, and isocyanate groups. The functional groups of the acrylic resin may bond with other compounds via a crosslinking agent (F), which will be described later, or may bond directly with other compounds without the use of a crosslinking agent (F). Bonding of the acrylic resin with other compounds via the functional groups tends to improve the reliability of packages obtained using, for example, a thermosetting resin film.

In composition (III), the ratio of the content of polymer component (A) to the total content of all components other than the solvent (i.e., in the thermosetting resin film, the ratio of the content of polymer component (A) to the total mass of the thermosetting resin film) is preferably 5 to 35% by mass, and more preferably 5 to 27% by mass, regardless of the type of polymer component (A).

[Thermosetting component (B)]
The thermosetting component (B) has thermosetting properties and is a component that heat-cures the thermosetting resin film to form a hard cured product.
The thermosetting component (B) contained in the composition (III) and the thermosetting resin film may be one type or two or more types, and when there are two or more types, the combination and ratio thereof can be selected arbitrarily.

Examples of the thermosetting component (B) include epoxy-based thermosetting resins, polyimide resins, and unsaturated polyester resins.
Among these, the thermosetting component (B) is preferably an epoxy-based thermosetting resin.

(epoxy thermosetting resin)
The epoxy thermosetting resin comprises an epoxy resin (B1) and a thermosetting agent (B2).
The epoxy-based thermosetting resin contained in the composition (III) and the thermosetting resin film may be one type or two or more types, and when two or more types are contained, the combination and ratio thereof can be selected arbitrarily.

Epoxy resin (B1)
Examples of the epoxy resin (B1) include known epoxy resins, such as bifunctional or higher functional epoxy compounds, including polyfunctional epoxy resins, biphenyl compounds, bisphenol A diglycidyl ether and its hydrogenated products, orthocresol novolac epoxy resins, dicyclopentadiene-type epoxy resins, biphenyl-type epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, and phenylene skeleton-type epoxy resins.

The epoxy resin (B1) may be an epoxy resin having an unsaturated hydrocarbon group. Epoxy resins having an unsaturated hydrocarbon group have higher compatibility with acrylic resins than epoxy resins without an unsaturated hydrocarbon group. Therefore, the use of an epoxy resin having an unsaturated hydrocarbon group tends to improve the reliability of packages obtained using, for example, a thermosetting resin film.

Examples of epoxy resins having unsaturated hydrocarbon groups include compounds obtained by converting some of the epoxy groups of a polyfunctional epoxy resin into groups having unsaturated hydrocarbon groups. Such compounds can be obtained, for example, by subjecting the epoxy groups to an addition reaction with (meth)acrylic acid or a derivative thereof.
Furthermore, examples of epoxy resins having an unsaturated hydrocarbon group include compounds in which a group having an unsaturated hydrocarbon group is directly bonded to an aromatic ring or the like constituting the epoxy resin.
The unsaturated hydrocarbon group is a polymerizable unsaturated group, and specific examples thereof include an ethenyl group (vinyl group), a 2-propenyl group (allyl group), a (meth)acryloyl group, and a (meth)acrylamide group, with an acryloyl group being preferred.

The number average molecular weight of the epoxy resin (B1) is not particularly limited, but from the viewpoints of the curability of the thermosetting resin film and the strength and heat resistance of the cured product of the thermosetting resin film (for example, a protective film), it is preferably 300 to 30,000, more preferably 400 to 10,000, and particularly preferably 500 to 3,000.
The epoxy equivalent of the epoxy resin (B1) is preferably 100 to 1000 g/eq, more preferably 100 to 600 g/eq.

Epoxy resin (B1) may be used alone or in combination of two or more types. When two or more types are used in combination, the combination and ratio thereof can be selected arbitrarily.

Heat curing agent (B2)
The heat curing agent (B2) functions as a curing agent for the epoxy resin (B1).
The thermosetting agent (B2) may be, for example, a compound having two or more functional groups capable of reacting with an epoxy group in one molecule. Examples of the functional group include a phenolic hydroxyl group, an alcoholic hydroxyl group, an amino group, a carboxyl group, and an anhydride group of an acid group. A phenolic hydroxyl group, an amino group, or an anhydride group of an acid group is preferred, and a phenolic hydroxyl group or an amino group is more preferred.

Among the heat curing agents (B2), examples of phenolic curing agents having a phenolic hydroxyl group include polyfunctional phenolic resins, biphenols, novolac-type phenolic resins, dicyclopentadiene-type phenolic resins, and aralkyl-type phenolic resins.
Among the heat curing agents (B2), examples of amine-based curing agents having an amino group include dicyandiamide (hereinafter sometimes abbreviated as "DICY").

The heat curing agent (B2) may have an unsaturated hydrocarbon group.
Examples of the thermosetting agent (B2) having an unsaturated hydrocarbon group include a compound in which some of the hydroxyl groups of a phenolic resin are substituted with a group having an unsaturated hydrocarbon group, and a compound in which a group having an unsaturated hydrocarbon group is directly bonded to an aromatic ring of a phenolic resin.
The unsaturated hydrocarbon group in the heat curing agent (B2) is the same as the unsaturated hydrocarbon group in the epoxy resin having an unsaturated hydrocarbon group described above.

Of the thermosetting agents (B2), for example, the number average molecular weight of resin components such as polyfunctional phenolic resins, novolac-type phenolic resins, dicyclopentadiene-type phenolic resins, and aralkyl-type phenolic resins is preferably 300 to 30,000, more preferably 400 to 10,000, and particularly preferably 500 to 3,000.
Of the thermosetting agents (B2), the molecular weight of the non-resin components such as biphenol and dicyandiamide is not particularly limited, but is preferably 60 to 500, for example.

Thermal curing agents (B2) may be used singly or in combination of two or more types. When two or more types are used in combination, the combination and ratio thereof can be selected arbitrarily.

In composition (III) and the thermosetting resin film, the content of the thermosetting agent (B2) is preferably 0.1 to 500 parts by mass, more preferably 1 to 200 parts by mass, per 100 parts by mass of the epoxy resin (B1), and may be, for example, any of 5 to 150 parts by mass, 10 to 100 parts by mass, and 15 to 75 parts by mass. When the content of the thermosetting agent (B2) is equal to or greater than the lower limit, curing of the thermosetting resin film proceeds more easily. When the content of the thermosetting agent (B2) is equal to or less than the upper limit, the moisture absorption rate of the thermosetting resin film is reduced, thereby further improving the reliability of, for example, a package obtained using the thermosetting resin film.

In composition (III), the ratio of the content of the thermosetting component (B) (for example, the total content of the epoxy resin (B1) and the thermosetting agent (B2)) to the total content of all components other than the solvent (i.e., the ratio of the content of the thermosetting component (B) in the thermosetting resin film to the total mass of the thermosetting resin film) is preferably 10 to 75 mass%, more preferably 15 to 70 mass%, and may be, for example, any of 15 to 50 mass%, 15 to 30 mass%, 35 to 70 mass%, and 55 to 70 mass%. When the ratio is within this range, when the thermosetting resin film is applied to the uneven surface, the fine grooves on the uneven surface are sufficiently filled, thereby enhancing the effects of suppressing peeling of the protective film from the uneven surface, suppressing the thermosetting resin film from remaining on the tops of the convex portions of the uneven surface, suppressing protrusion of the thermosetting resin film on the uneven surface, and suppressing repelling of the thermosetting resin film and its cured product on the uneven surface, and a hard cured product (e.g., protective film) can be formed.
Furthermore, in order to obtain such effects more significantly, the content of the thermosetting component (B) may be appropriately adjusted depending on the type of the polymer component (A).

[Filler (D)]
The X value can be more easily adjusted by adjusting the amount of filler (D) in the composition (III) and the thermosetting resin film. For example, by adjusting the amount of filler (D) in the composition (III) and the thermosetting resin film, the linear expansion coefficient of the cured product of the thermosetting resin film (e.g., a protective film) can be more easily adjusted. For example, by optimizing the linear expansion coefficient of the protective film (e.g., a first protective film) for the object on which the protective film is formed, the reliability of the package obtained using the thermosetting resin film can be further improved. Furthermore, by using a thermosetting resin film containing filler (D), the moisture absorption rate of the cured product of the thermosetting resin film (e.g., a protective film) can be reduced and the heat dissipation properties can be improved.

The filler (D) may be either an organic filler or an inorganic filler, but is preferably an inorganic filler.
Preferred inorganic fillers include, for example, powders of silica, alumina, talc, calcium carbonate, titanium white, red iron oxide, silicon carbide, boron nitride, and the like; beads obtained by spheronizing these inorganic fillers; surface-modified products of these inorganic fillers; single-crystal fibers of these inorganic fillers; and glass fibers.
Among these, the inorganic filler is preferably silica or alumina.

The filler (D) contained in composition (III) and the thermosetting resin film may be one type only or two or more types, and if there are two or more types, the combination and ratio thereof can be selected arbitrarily.

In composition (III), the ratio of the content of filler (D) to the total content of all components other than the solvent (i.e., the ratio of the content of filler (D) to the total mass of the thermosetting resin film in the thermosetting resin film) is preferably 10 to 65% by mass, more preferably 15 to 55% by mass, and may be, for example, 15 to 40% by mass, 15 to 30% by mass, 30 to 55% by mass, or 40 to 55% by mass. By having this ratio within this range, when the thermosetting resin film is applied to the uneven surface, the fine grooves on the uneven surface are sufficiently filled, thereby enhancing the effects of preventing peeling of the protective film from the uneven surface, preventing the thermosetting resin film from remaining on the tops of the convex portions of the uneven surface, preventing protrusion of the thermosetting resin film from the uneven surface, and preventing repelling of the thermosetting resin film and its cured product on the uneven surface. Furthermore, the linear expansion coefficient can be more easily adjusted.

[Additive (I)]
The composition (III) and the thermosetting resin film may contain an additive (I). Examples of the additive (I) include a component for adjusting the X value.
Among these, examples of the additive (I) that are preferable in terms of making it easier to adjust the X value include rheology control agents, surfactants, and silicone oils.

More specifically, examples of the rheology control agent include polyhydroxycarboxylic acid esters, polycarboxylic acids, and polyamide resins.
Examples of the surfactant include modified siloxane and acrylic polymer.
Examples of the silicone oil include aralkyl-modified silicone oil and modified polydimethylsiloxane, and examples of the modifying group include aralkyl groups; polar groups such as hydroxy groups; and groups having an unsaturated bond such as vinyl groups and phenyl groups.

Additives (I) other than those mentioned above may also include various other general-purpose additives such as plasticizers, antistatic agents, antioxidants, gettering agents, ultraviolet absorbers, and tackifiers.

The additive (I) contained in composition (III) and the thermosetting resin film may be one type only or two or more types, and if there are two or more types, the combination and ratio thereof can be selected arbitrarily.

The content of the composition (III) and the additive (I) in the thermosetting resin film is not particularly limited and can be adjusted appropriately depending on the type and purpose.
For example, when the purpose is to adjust the X value, the ratio of the content of additive (I) to the total content of all components other than the solvent in composition (III) (i.e., the ratio of the content of additive (I) in the thermosetting resin film to the total mass of the thermosetting resin film) is preferably 0.5 to 10 mass%, more preferably 0.5 to 7 mass%, and even more preferably 0.5 to 5 mass%.

[Curing accelerator (C)]
The composition (III) and the thermosetting resin film may contain a curing accelerator (C). The curing accelerator (C) is a component for adjusting the curing rate of the composition (III). The curing accelerator (C) is preferably a powder at room temperature, since this makes it easier to adjust the gelation time of the thermosetting resin film at 180°C to 300 seconds or more.
Preferred curing accelerators (C) include, for example, tertiary amines such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol; imidazoles (imidazoles in which one or more hydrogen atoms are substituted with groups other than hydrogen atoms) such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole; organic phosphines (phosphines in which one or more hydrogen atoms are substituted with organic groups) such as tributylphosphine, diphenylphosphine, and triphenylphosphine; and tetraphenylboron salts such as tetraphenylphosphonium tetraphenylborate and triphenylphosphine tetraphenylborate.

The curing accelerator (C) contained in composition (III) and the thermosetting resin film may be one type or two or more types, and if there are two or more types, the combination and ratio thereof can be selected arbitrarily.

When a curing accelerator (C) is used, the content of the curing accelerator (C) in the composition (III) and the thermosetting resin film is preferably 0.01 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass, per 100 parts by mass of the thermosetting component (B). When the content of the curing accelerator (C) is at or above the lower limit, the effects of using the curing accelerator (C) are more pronounced. When the content of the curing accelerator (C) is at or below the upper limit, for example, the effect of suppressing the highly polar curing accelerator (C) from migrating and segregating to the adhesive interface with the adherend under high temperature and high humidity conditions is enhanced, thereby further improving the reliability of packages obtained using the thermosetting resin film.

[Coupling agent (E)]
The composition (III) and the thermosetting resin film may contain a coupling agent (E). By using a coupling agent (E) having a functional group capable of reacting with an inorganic compound or an organic compound, the adhesiveness and adhesion of the thermosetting resin film to an adherend can be improved. Furthermore, by using the coupling agent (E), the water resistance of the cured product of the thermosetting resin film (e.g., a protective film) can be improved without impairing the heat resistance.

The coupling agent (E) is preferably a compound having a functional group capable of reacting with the functional group of the polymer component (A), the thermosetting component (B), etc., and is more preferably a silane coupling agent.
Preferred examples of the silane coupling agent include 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxymethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-(2-aminoethylamino)propyltrimethoxysilane, 3-(2- Examples thereof include bis(3-(aminoethylamino)propylmethyldiethoxysilane, 3-(phenylamino)propyltrimethoxysilane, 3-anilinopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, bis(3-triethoxysilylpropyl)tetrasulfane, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, and imidazole silane.

The coupling agent (E) contained in composition (III) and the thermosetting resin film may be one type only or two or more types, and if there are two or more types, the combination and ratio thereof can be selected arbitrarily.

When coupling agent (E) is used, the content of coupling agent (E) in composition (III) and the thermosetting resin film is preferably 0.03 to 10 parts by mass, more preferably 0.05 to 6 parts by mass, and particularly preferably 0.1 to 3 parts by mass, per 100 parts by mass of the total content of polymer component (A) and thermosetting component (B). When the content of coupling agent (E) is at or above the lower limit, the effects of using coupling agent (E), such as improved dispersibility of filler (D) in the resin and improved adhesion of the thermosetting resin film to the adherend, are more pronounced. When the content of coupling agent (E) is at or below the upper limit, outgassing is further suppressed.

[Crosslinking agent (F)]
When the polymer component (A) has a functional group capable of bonding to other compounds, such as a vinyl group, a (meth)acryloyl group, an amino group, a hydroxyl group, a carboxyl group, or an isocyanate group, the composition (III) and the thermosetting resin film may contain a crosslinking agent (F). The crosslinking agent (F) is a component for bonding the functional group in the polymer component (A) to other compounds to form a crosslink, and by crosslinking in this manner, the initial adhesive strength and cohesive strength of the thermosetting resin film can be adjusted.

Examples of crosslinking agents (F) include organic polyvalent isocyanate compounds, organic polyvalent imine compounds, metal chelate crosslinking agents (crosslinking agents having a metal chelate structure), and aziridine crosslinking agents (crosslinking agents having an aziridinyl group).

Examples of the organic polyisocyanate compounds include aromatic polyisocyanate compounds, aliphatic polyisocyanate compounds, and alicyclic polyisocyanate compounds (hereinafter, these compounds may be collectively referred to as "aromatic polyisocyanate compounds, etc."); trimers, isocyanurates, and adducts of the aromatic polyisocyanate compounds; and isocyanate-terminated urethane prepolymers obtained by reacting the aromatic polyisocyanate compounds, etc. with polyol compounds. The "adduct" refers to the reaction product of the aromatic polyisocyanate compound, aliphatic polyisocyanate compound, or alicyclic polyisocyanate compound with a low-molecular-weight active hydrogen-containing compound such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, or castor oil. Examples of the adduct include the xylylene diisocyanate adduct of trimethylolpropane, as described below. Furthermore, the term "isocyanate-terminated urethane prepolymer" refers to a prepolymer having a urethane bond and an isocyanate group at the end of the molecule.

More specifically, examples of the organic polyisocyanate compound include 2,4-tolylene diisocyanate; 2,6-tolylene diisocyanate; 1,3-xylylene diisocyanate; 1,4-xylylene diisocyanate; diphenylmethane-4,4'-diisocyanate; diphenylmethane-2,4'-diisocyanate; 3-methyldiphenylmethane diisocyanate; hexamethylene diisocyanate; isophorone diisocyanate; dicyclohexylmethane-4,4'-diisocyanate; dicyclohexylmethane-2,4'-diisocyanate; compounds in which one or more of tolylene diisocyanate, hexamethylene diisocyanate, and xylylene diisocyanate are added to all or some of the hydroxyl groups of a polyol such as trimethylolpropane; lysine diisocyanate, etc.

Examples of the organic polyvalent imine compounds include N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinylpropionate, tetramethylolmethane-tri-β-aziridinylpropionate, N,N'-toluene-2,4-bis(1-aziridinecarboxamide)triethylenemelamine, etc.

When an organic polyisocyanate compound is used as the crosslinking agent (F), it is preferable to use a hydroxyl group-containing polymer as the polymer component (A). When the crosslinking agent (F) contains an isocyanate group and the polymer component (A) contains a hydroxyl group, a crosslinked structure can be easily introduced into the thermosetting resin film by the reaction between the crosslinking agent (F) and the polymer component (A).

The crosslinking agent (F) contained in composition (III) and the thermosetting resin film may be one type or two or more types, and if there are two or more types, the combination and ratio thereof can be selected arbitrarily.

When crosslinking agent (F) is used, the content of crosslinking agent (F) in composition (III) is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, and particularly preferably 0.5 to 5 parts by mass, per 100 parts by mass of polymer component (A). When the content of crosslinking agent (F) is at or above the lower limit, the effects of using crosslinking agent (F) are more pronounced. When the content of crosslinking agent (F) is at or below the upper limit, excessive use of crosslinking agent (F) is suppressed.

[Other ingredients]
The composition (III) and the thermosetting resin film may contain other components that do not fall under any of the above-mentioned polymer component (A), thermosetting component (B), filler (D), additive (I), curing accelerator (C), coupling agent (E), and crosslinking agent (F), as long as the effects of the present invention are not impaired.
Examples of the other components include an energy ray curable resin and a photopolymerization initiator.

The other components contained in the composition (III) and the thermosetting resin film may be one type only or two or more types, and when there are two or more types, the combination and ratio thereof can be selected arbitrarily.
The contents of the composition (III) and the other components in the thermosetting resin film are not particularly limited and may be appropriately selected depending on the purpose.

[solvent]
Composition (III) preferably further contains a solvent, since composition (III) containing a solvent has good handleability.
The solvent is not particularly limited, but preferred examples include hydrocarbons such as toluene and xylene; alcohols such as methanol, ethanol, 2-propanol, isobutyl alcohol (2-methylpropan-1-ol), and 1-butanol; esters such as ethyl acetate; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran; and amides (compounds having an amide bond) such as dimethylformamide and N-methylpyrrolidone.
The composition (III) may contain only one type of solvent, or two or more types of solvents. When two or more types of solvents are contained, the combination and ratio thereof can be selected arbitrarily.

A more preferred solvent contained in composition (III) is, for example, methyl ethyl ketone, etc., which allows the components contained in composition (III) to be mixed more uniformly.

The solvent content of composition (III) is not particularly limited and may be selected appropriately depending on, for example, the types of components other than the solvent.

<Method for producing thermosetting resin film-forming composition>
A thermosetting resin film-forming composition such as composition (III) can be obtained by blending the components that constitute the composition.
The order of addition of the components when blending is not particularly limited, and two or more components may be added simultaneously.
The method for mixing the components during blending is not particularly limited, and may be appropriately selected from known methods such as a method of mixing by rotating a stirrer or stirring blades, a method of mixing using a mixer, or a method of mixing by applying ultrasound.
The temperature and time for adding and mixing each component are not particularly limited as long as the components do not deteriorate, and may be adjusted appropriately. A temperature of 15 to 30°C is preferred.

An example of a preferred thermosetting resin film of the present embodiment is a thermosetting resin film,
a thermosetting resin film measuring 10 mm x 10 mm x 1 mm is used as a first test piece, and when the first test piece is placed on a stainless steel plate heated to 180°C in a recessed sample holder of an automatic curing time measuring device "Madoka," and the mixture is heated and stirred under the above conditions, the gelation time from the time when the torque of the stirring blade reaches 2.5 gf cm is any one of 300 seconds or more, 310 seconds or more, 320 seconds or more, 330 seconds or more, and 340 seconds or more;
the thermosetting resin film contains a polymer component (A), a thermosetting component (B), and a filler (D),
The content ratio of the thermosetting component (B) in the thermosetting resin film relative to the total mass of the thermosetting resin film is either 10 to 75 mass% or 15 to 70 mass%,
The thermosetting resin film may have a content ratio of the filler (D) relative to the total mass of the thermosetting resin film of 10 to 65 mass% or 15 to 55 mass%.

Another example of a preferable thermosetting resin film of the present embodiment is a thermosetting resin film,
a thermosetting resin film measuring 10 mm x 10 mm x 1 mm is used as a first test piece, and when the first test piece is placed on a stainless steel plate heated to 180°C in a recessed sample holder of an automatic curing time measuring device "Madoka," and the mixture is heated and stirred under the above conditions, the gelation time from the time the first test piece is placed on a stainless steel plate heated to 180°C to the time the torque of the stirring blade reaches 2.5 gf cm is any one of 300 seconds or more, 310 seconds or more, 320 seconds or more, 330 seconds or more, and 340 seconds or more;
the X value is any one of 19 or more and less than 10,000, 19 to 5,000, 25 to 2,000, 30 to 1,000, 35 to 500, 40 to 300, 45 to 100, and 50 to 70;
the thermosetting resin film contains a polymer component (A), a thermosetting component (B), and a filler (D),
The content ratio of the thermosetting component (B) in the thermosetting resin film relative to the total mass of the thermosetting resin film is either 10 to 75 mass% or 15 to 70 mass%,
The thermosetting resin film may have a content ratio of the filler (D) relative to the total mass of the thermosetting resin film of 10 to 65 mass% or 15 to 55 mass%.

Another example of a preferable thermosetting resin film of the present embodiment is a thermosetting resin film,
a thermosetting resin film measuring 10 mm x 10 mm x 1 mm is used as a first test piece, and when the first test piece is placed on a stainless steel plate heated to 180°C in a recessed sample holder of an automatic curing time measuring device "Madoka," and the mixture is heated and stirred under the above conditions, the gelation time from the time when the torque of the stirring blade reaches 2.5 gf cm is any one of 300 seconds or more, 310 seconds or more, 320 seconds or more, 330 seconds or more, and 340 seconds or more;
the X value is any one of 19 or more and less than 10,000, 19 to 5,000, 25 to 2,000, 30 to 1,000, 35 to 500, 40 to 300, 45 to 100, and 50 to 70;
the thermosetting resin film contains a polymer component (A), a thermosetting component (B), a filler (D), and an additive (I);
The content ratio of the thermosetting component (B) in the thermosetting resin film relative to the total mass of the thermosetting resin film is either 10 to 75 mass% or 15 to 70 mass%,
The content ratio of the filler (D) in the thermosetting resin film relative to the total mass of the thermosetting resin film is either 10 to 65 mass% or 15 to 55 mass%,
The thermosetting resin film may have a content ratio of the additive (I) relative to the total mass of the thermosetting resin film of 0.5 to 10 mass%, 0.5 to 7 mass%, or 0.5 to 5 mass%.

◇Composite sheet A composite sheet according to one embodiment of the present invention comprises a support sheet and a resin film provided on one side of the support sheet, and the resin film is the thermosetting resin film according to one embodiment of the present invention described above.
As described above, by using the composite sheet of this embodiment, the thermosetting resin film can be adhered well to the uneven surface of the object to which it is to be attached, and at this time, the fine grooves on the uneven surface can be sufficiently filled, thereby preventing the protective film from peeling off from the uneven surface.

In this specification, when the thermosetting resin film is used to form the first protective film, the composite sheet is referred to as a "sheet for forming the first protective film," and the support sheet in the sheet for forming the first protective film is referred to as a "first support sheet."
On the other hand, to provide a second protective film on the surface (back surface) opposite to the bump-formed surface of the semiconductor wafer or semiconductor chip, a second protective film-forming sheet is used, which is configured to include a second protective film-forming film for forming the second protective film. Examples of the second protective film-forming sheet include a sheet configured to include a dicing sheet and a second protective film-forming film provided on the dicing sheet. When the dicing sheet includes the same material as the support sheet, this support sheet is referred to as a "second support sheet."
Similarly, for example, if the first support sheet has a substrate and an adhesive layer, these will be referred to as the "first substrate" and the "first adhesive layer," and if the second support sheet has a substrate and an adhesive layer, these will be referred to as the "second substrate" and the "second adhesive layer."

FIG. 3 is a cross-sectional view schematically showing an example of the composite sheet of this embodiment.
The composite sheet 1 shown here is composed of a support sheet 10 and a thermosetting resin film 12 provided on one side 10a of the support sheet 10 (sometimes referred to as the "first side" in this specification).
The support sheet 10 is composed of a substrate 11, a buffer layer 13 provided on one surface 11a of the substrate 11 (sometimes referred to as the "first surface" in this specification), and an adhesive layer 14 provided on the surface 13a of the buffer layer 13 opposite the substrate 11 side (sometimes referred to as the "first surface" in this specification).
That is, the composite sheet 1 is constructed by laminating a substrate 11, a buffer layer 13, a pressure-sensitive adhesive layer 14, and a thermosetting resin film 12 in this order in the thickness direction. The pressure-sensitive adhesive layer 14 is the outermost layer on one side of the support sheet 10 (the thermosetting resin film 12 side), and the surface 14a opposite the buffer layer 13 side (sometimes referred to as the "first surface" in this specification) is the same as the first surface 10a of the support sheet 10.

In the composite sheet 1, both the buffer layer 13 and the adhesive layer 14 are positioned between the substrate 11 and the thermosetting resin film 12.

The thermosetting resin film 12 is the thermosetting resin film according to one embodiment of the present invention described above.
The surface (first surface) 12a of the thermosetting resin film 12 opposite to the buffer layer 13 side is the surface to be attached to the uneven surface of the thermosetting resin film 12 (in other words, the composite sheet 1).

The composite sheet of this embodiment is not limited to that shown in Figure 3, and some of the components shown in Figure 3 may be modified, deleted, or added, as long as the effects of the present invention are not impaired.

For example, the support sheet in the composite sheet of this embodiment may be one that is constituted by the above-mentioned substrate, buffer layer, and adhesive layer, or one that is constituted by only a substrate; one that is constituted by a substrate and an adhesive layer provided on one surface of the substrate; or one that is constituted by a substrate and a buffer layer provided on one surface of the substrate.
When the support sheet includes a substrate and a pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer is disposed between the substrate and the resin film in the composite sheet. When the support sheet includes a substrate and a buffer layer, the buffer layer is disposed between the substrate and the resin film in the composite sheet.
Of these, the support sheet is more preferably one comprising the above-mentioned substrate, buffer layer, and adhesive layer.

For example, in the composite sheet of this embodiment, the support sheet (support sheet 10 in the composite sheet 1 shown in Figure 3) may have an adhesion layer between the substrate (substrate 11 in the composite sheet 1 shown in Figure 3) and the buffer layer (buffer layer 13 in the composite sheet 1 shown in Figure 3).
The adhesion layer improves the adhesion between the substrate and the buffer layer and highly suppresses peeling between the substrate and the buffer layer in the composite sheet, so that the composite sheet having the adhesion layer can more stably maintain the laminated structure of the substrate, adhesion layer, and buffer layer during use.
The adhesive layer is in the form of a sheet or a film.
A preferred adhesive layer is, for example, one containing an ethylene-vinyl acetate copolymer resin (EVA).

For example, the composite sheet of this embodiment may have a release film on the outermost layer (thermosetting resin film 12 in the composite sheet 1 shown in FIG. 3) on the side opposite to the substrate.
Next, each layer constituting the composite sheet of this embodiment will be described.

Substrate The substrate is in the form of a sheet or film, and examples of the constituent materials thereof include various resins.
Examples of the resin include polyethylenes such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE); polyolefins other than polyethylene such as polypropylene, polybutene, polybutadiene, polymethylpentene, and norbornene resin; ethylene-based copolymers (copolymers obtained using ethylene as a monomer) such as ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid ester copolymer, and ethylene-norbornene copolymer; and vinyl chloride-based resins (copolymers obtained using vinyl chloride as a monomer) such as polyvinyl chloride and vinyl chloride copolymer. Examples of the polyester include polyesters such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyethylene isophthalate, polyethylene-2,6-naphthalenedicarboxylate, and wholly aromatic polyesters in which all structural units have aromatic cyclic groups; copolymers of two or more of the above polyesters; poly(meth)acrylic acid esters; polyurethanes; polyurethane acrylates; polyimides; polyamides; polycarbonates; fluororesins; polyacetals; modified polyphenylene oxides; polyphenylene sulfides; polysulfones; and polyether ketones.
Further, examples of the resin include polymer alloys such as mixtures of the polyester and other resins. The polymer alloys of the polyester and other resins preferably contain a relatively small amount of resin other than polyester.
Examples of the resin include crosslinked resins in which one or more of the resins exemplified above are crosslinked; and modified resins such as ionomers using one or more of the resins exemplified above.

The resin constituting the base material may be one type only, or two or more types, and if two or more types are used, the combination and ratio of these can be selected arbitrarily.

The substrate may be a single layer (monolayer) or may be two or more layers. If it is a multiple layer substrate, these layers may be the same or different from each other, and there are no particular limitations on the combination of these layers.

The thickness of the substrate is preferably 5 to 1000 μm, more preferably 10 to 500 μm, even more preferably 15 to 300 μm, and particularly preferably 20 to 180 μm.
Here, the "thickness of the substrate" means the thickness of the entire substrate, and for example, the thickness of a substrate consisting of multiple layers means the total thickness of all layers that make up the substrate.

It is preferable that the substrate has a high degree of thickness precision, i.e., that thickness variation is suppressed regardless of location. Among the above-mentioned constituent materials, materials that can be used to form substrates with such high thickness precision include, for example, polyethylene, polyolefins other than polyethylene, polyethylene terephthalate, and ethylene-vinyl acetate copolymer.

In addition to the main constituent materials such as the resin, the substrate may contain various known additives such as fillers, colorants, antistatic agents, antioxidants, organic lubricants, catalysts, and softeners (plasticizers).

The substrate may be transparent or opaque, may be colored as desired, or may have other layers vapor-deposited on it.

The substrate can be manufactured by a known method. For example, a substrate containing a resin can be manufactured by molding a resin composition containing the resin.

Buffer Layer The buffer layer is in the form of a sheet or film, and has a buffering effect against forces applied to the buffer layer and layers adjacent thereto. Here, examples of the "layers adjacent to the buffer layer" include the thermosetting resin film, a layer corresponding to the cured product thereof (e.g., a protective film such as the first protective film), and a pressure-sensitive adhesive layer.

The material constituting the buffer layer is not particularly limited.

Preferred buffer layers include, for example, those containing urethane (meth)acrylate.

As with the thermosetting resin film described above, strain is generated in a test piece of a buffer layer with a diameter of 25 mm and a thickness of 1 mm at a temperature of 90°C and a frequency of 1 Hz, and the storage modulus of the test piece is measured. When the storage modulus of the test piece at a strain of 300% is designated as Gb300, it is preferable that Gb300 be greater than or equal to Gc300 (Gb300 ≥ Gc300). By using the composite sheet that satisfies these conditions to attach the thermosetting resin film to an uneven surface, the upper parts of the convex portions of the uneven surface (e.g., bumps on a semiconductor wafer) can more easily penetrate the thermosetting resin film.

As described above, when strains ranging from 0.01% to 1000% are applied to a test piece of the buffer layer and the storage modulus Gb of the test piece is measured, and strains ranging from 0.01% to 1000% are applied to a test piece of the thermosetting resin film and the storage modulus Gc of the test piece are measured, and Gb and Gc are compared for the same strain, it is preferable that Gb is equal to or greater than Gc (Gb ≥ Gc) over the entire strain range of 0.01% to 1000%, and it is even more preferable that Gb is equal to or greater than Gc over the entire strain range of 10% to 1000%. By using the composite sheet that satisfies these conditions to attach the thermosetting resin film to an uneven surface, the upper parts of the convex portions of the uneven surface (e.g., bumps on a semiconductor wafer) can more easily penetrate the thermosetting resin film.

The buffer layer may consist of one layer (single layer), or two or more layers. If it consists of multiple layers, these layers may be the same or different, and there are no particular restrictions on the combination of these layers.

The thickness of the buffer layer is preferably 150 to 1000 μm, more preferably 150 to 800 μm, even more preferably 200 to 600 μm, and particularly preferably 250 to 500 μm.
Here, the "thickness of the buffer layer" means the thickness of the entire buffer layer, and for example, the thickness of a buffer layer consisting of multiple layers means the total thickness of all layers that make up the buffer layer.

<<Buffer layer forming composition>>
The buffer layer can be formed using a buffer layer-forming composition containing the constituent materials of the buffer layer, such as the resin. For example, the buffer layer can be formed at the desired location by extruding the buffer layer-forming composition onto the surface on which the buffer layer is to be formed. A more specific method for forming the buffer layer will be described in detail later, along with methods for forming other layers. The ratio of the contents of the components that do not vaporize at room temperature in the buffer layer-forming composition is usually the same as the ratio of the contents of the components of the buffer layer.

<Buffer layer forming composition (V)>
The buffer layer-forming composition may be, for example, a buffer layer-forming composition (V) containing urethane (meth)acrylate.

The content of urethane (meth)acrylate in the buffer layer forming composition (V) and the buffer layer is preferably 80 to 100% by mass.

[Other ingredients]
The buffer layer-forming composition (V) and the buffer layer may contain components other than the urethane (meth)acrylate within the range that does not impair the effects of the present invention.
The other components are not particularly limited and can be appropriately selected depending on the purpose.

The other components contained in the buffer layer-forming composition (V) and the buffer layer may be one type or two or more types, and when there are two or more types, the combination and ratio thereof can be selected arbitrarily.
The contents of the buffer layer-forming composition (V) and the other components of the buffer layer are not particularly limited and may be appropriately selected depending on the purpose.

Adhesive Layer The adhesive layer is in the form of a sheet or film and contains an adhesive.
Examples of the adhesive include adhesive resins such as acrylic resins, urethane resins, rubber-based resins, silicone resins, epoxy-based resins, polyvinyl ethers, polycarbonates, and ester-based resins, with acrylic resins being preferred.

In this specification, the term "adhesive resin" includes both resins that have adhesive properties and resins that have adhesive properties. For example, adhesive resins include not only resins that are adhesive themselves, but also resins that become adhesive when used in combination with other components such as additives, and resins that become adhesive in the presence of a trigger such as heat or water.

The adhesive layer may consist of one layer (single layer), or two or more layers. If it consists of multiple layers, these layers may be the same or different, and there are no particular restrictions on the combination of these layers.

The thickness of the pressure-sensitive adhesive layer is preferably 10 to 180 μm, more preferably 30 to 120 μm, and particularly preferably 40 to 80 μm. When the thickness of the pressure-sensitive adhesive layer is equal to or greater than the lower limit, the effect of providing the pressure-sensitive adhesive layer is more pronounced. When the thickness of the pressure-sensitive adhesive layer is equal to or less than the upper limit, the support sheet can be made thinner.
Here, "thickness of the adhesive layer" means the thickness of the entire adhesive layer, and for example, the thickness of an adhesive layer consisting of multiple layers means the total thickness of all layers that make up the adhesive layer.

The adhesive layer may be formed using an energy ray-curable adhesive or a non-energy ray-curable adhesive. That is, the adhesive layer may be either energy ray-curable or non-energy ray-curable. The physical properties of an energy ray-curable adhesive layer can be easily adjusted before and after curing. For example, by curing the energy ray-curable adhesive layer before picking up the semiconductor chip with the first protective film described below, the semiconductor chip with the first protective film can be more easily picked up.

In this specification, "energy rays" refers to electromagnetic waves or charged particle beams that have an energy quantum. Examples of energy rays include ultraviolet rays, radioactive rays, and electron beams. Ultraviolet rays can be irradiated using, for example, a high-pressure mercury lamp, a fusion lamp, a xenon lamp, a black light, or an LED lamp as an ultraviolet light source. Electron beams can be irradiated using those generated by an electron beam accelerator or the like.
In this specification, "energy ray curable" means a property of being cured by irradiation with energy rays, and "non-energy ray curable" means a property of not being cured even when irradiated with energy rays.
Moreover, "non-curable" means a property that does not cure by any means such as heating or irradiation with energy rays.

<<Adhesive composition>>
The pressure-sensitive adhesive layer can be formed using a pressure-sensitive adhesive composition containing a pressure-sensitive adhesive. For example, the pressure-sensitive adhesive composition can be applied to a surface on which the pressure-sensitive adhesive layer is to be formed, and then dried as necessary to form the pressure-sensitive adhesive layer at the desired location. The ratio of the contents of the components that do not vaporize at room temperature in the pressure-sensitive adhesive composition is usually the same as the ratio of the contents of the components in the pressure-sensitive adhesive layer.

The adhesive composition can be applied, for example, in the same manner as in the application of the thermosetting resin film-forming composition described above.

The drying conditions for the pressure-sensitive adhesive composition are not particularly limited. If the pressure-sensitive adhesive composition contains a solvent, as described below, it is preferable to heat-dry it. Pressure-sensitive adhesive compositions containing a solvent are preferably dried, for example, at 70 to 130°C for 10 seconds to 5 minutes.

When providing a pressure-sensitive adhesive layer on a substrate or a buffer layer, for example, a pressure-sensitive adhesive composition may be applied to the substrate or the buffer layer and dried as necessary to laminate the pressure-sensitive adhesive layer on the substrate or the buffer layer. Alternatively, when providing a pressure-sensitive adhesive layer on a substrate or a buffer layer, for example, a pressure-sensitive adhesive composition may be applied to a release film and dried as necessary to form a pressure-sensitive adhesive layer on the release film, and the exposed surface of this pressure-sensitive adhesive layer may be attached to one surface of the substrate or the buffer layer to laminate the pressure-sensitive adhesive layer on the substrate or the buffer layer. In this case, the release film may be removed at any time during the manufacturing process or during use of the composite sheet.

When the pressure-sensitive adhesive layer is energy ray-curable, examples of the energy ray-curable pressure-sensitive adhesive composition include pressure-sensitive adhesive composition (I-1) containing a non-energy ray-curable pressure-sensitive adhesive resin (I-1a) (hereinafter sometimes abbreviated as "pressure-sensitive adhesive resin (I-1a)") and an energy ray-curable compound; pressure-sensitive adhesive composition (I-2) containing an energy ray-curable pressure-sensitive adhesive resin (I-2a) (hereinafter sometimes abbreviated as "pressure-sensitive adhesive resin (I-2a)") in which an unsaturated group has been introduced into the side chain of the pressure-sensitive adhesive resin (I-1a); and pressure-sensitive adhesive composition (I-3) containing the pressure-sensitive adhesive resin (I-2a) and an energy ray-curable low-molecular-weight compound.

Examples of the pressure-sensitive adhesive composition (I-1), pressure-sensitive adhesive composition (I-2), and pressure-sensitive adhesive composition (I-3) include the first pressure-sensitive adhesive composition (I-1), first pressure-sensitive adhesive composition (I-2), and first pressure-sensitive adhesive composition (I-3) described in paragraphs 0045 to 0105 of WO 2017/078047.

When the adhesive layer is non-energy ray curable, examples of non-energy ray curable adhesive compositions include adhesive composition (I-4) containing the adhesive resin (I-1a).

<<Method of manufacturing pressure-sensitive adhesive composition>>
The pressure-sensitive adhesive compositions such as the pressure-sensitive adhesive compositions (I-1) to (I-4) can be obtained by blending the pressure-sensitive adhesive and, if necessary, components other than the pressure-sensitive adhesive, for constituting the pressure-sensitive adhesive composition.
The order of addition of the components when blending is not particularly limited, and two or more components may be added simultaneously.
The method for mixing the components during blending is not particularly limited, and may be appropriately selected from known methods such as a method of mixing by rotating a stirrer or stirring blades, a method of mixing using a mixer, or a method of mixing by applying ultrasound.
The temperature and time for adding and mixing each component are not particularly limited as long as the components do not deteriorate, and may be adjusted appropriately. A temperature of 15 to 30°C is preferred.

Thermosetting Resin Film The thermosetting resin film in the composite sheet of this embodiment is the same as that described above, and therefore a detailed description thereof will be omitted here.

An example of a preferred composite sheet of the present embodiment is a composite sheet including a support sheet and a resin film provided on one surface of the support sheet,
the support sheet comprises a substrate, a buffer layer provided on one surface of the substrate, and a pressure-sensitive adhesive layer provided on the surface of the buffer layer opposite to the substrate side, the buffer layer and the pressure-sensitive adhesive layer being disposed between the substrate and the resin film;
the resin film is a thermosetting resin film,
A thermosetting resin film measuring 10 mm x 10 mm x 1 mm was used as a first test piece, and when the first test piece was placed on a stainless steel plate heated to 180°C in a recessed sample holder of an automatic curing time measuring device "Madoka," and the mixture was heated and stirred under the following conditions, the gelation time from the time when the torque of the stirring blade reached 2.5 gf cm was any one of 300 seconds or more, 310 seconds or more, 320 seconds or more, 330 seconds or more, and 340 seconds or more.
the thermosetting resin film contains a polymer component (A), a thermosetting component (B), and a filler (D),
The content ratio of the thermosetting component (B) in the thermosetting resin film relative to the total mass of the thermosetting resin film is either 10 to 75 mass% or 15 to 70 mass%,
In the thermosetting resin film, the content ratio of the filler (D) relative to the total mass of the thermosetting resin film is either 10 to 65 mass% or 15 to 55 mass%.

Another example of a preferred composite sheet of the present embodiment is a composite sheet including a support sheet and a resin film provided on one surface of the support sheet,
the support sheet comprises a substrate, a buffer layer provided on one surface of the substrate, and a pressure-sensitive adhesive layer provided on the surface of the buffer layer opposite to the substrate side, the buffer layer and the pressure-sensitive adhesive layer being disposed between the substrate and the resin film;
the resin film is a thermosetting resin film,
A thermosetting resin film measuring 10 mm x 10 mm x 1 mm was used as a first test piece, and when the first test piece was placed on a stainless steel plate heated to 180°C in a recessed sample holder of an automatic curing time measuring device "Madoka," and the mixture was heated and stirred under the following conditions, the gelation time from the time when the torque of the stirring blade reached 2.5 gf cm was any one of 300 seconds or more, 310 seconds or more, 320 seconds or more, 330 seconds or more, and 340 seconds or more.
the X value is any one of 19 or more and less than 10,000, 19 to 5,000, 25 to 2,000, 30 to 1,000, 35 to 500, 40 to 300, 45 to 100, and 50 to 70;
the thermosetting resin film contains a polymer component (A), a thermosetting component (B), and a filler (D),
The content ratio of the thermosetting component (B) in the thermosetting resin film relative to the total mass of the thermosetting resin film is either 10 to 75 mass% or 15 to 70 mass%,
In the thermosetting resin film, the content ratio of the filler (D) relative to the total mass of the thermosetting resin film is either 10 to 65 mass% or 15 to 55 mass%.

Yet another example of a preferable composite sheet of the present embodiment is a composite sheet including a support sheet and a resin film provided on one surface of the support sheet,
the support sheet comprises a substrate, a buffer layer provided on one surface of the substrate, and a pressure-sensitive adhesive layer provided on the surface of the buffer layer opposite to the substrate side, the buffer layer and the pressure-sensitive adhesive layer being disposed between the substrate and the resin film;
the resin film is a thermosetting resin film,
a thermosetting resin film measuring 10 mm x 10 mm x 1 mm is used as a first test piece, and when the first test piece is placed on a stainless steel plate heated to 180°C in a recessed sample holder of an automatic curing time measuring device "Madoka," and the mixture is heated and stirred under the above conditions, the gelation time from the time when the torque of the stirring blade reaches 2.5 gf cm is any one of 300 seconds or more, 310 seconds or more, 320 seconds or more, 330 seconds or more, and 340 seconds or more;
the X value is any one of 19 or more and less than 10,000, 19 to 5,000, 25 to 2,000, 30 to 1,000, 35 to 500, 40 to 300, 45 to 100, and 50 to 70;
the thermosetting resin film contains a polymer component (A), a thermosetting component (B), a filler (D), and an additive (I);
The content ratio of the thermosetting component (B) in the thermosetting resin film relative to the total mass of the thermosetting resin film is either 10 to 75 mass% or 15 to 70 mass%,
The content ratio of the filler (D) in the thermosetting resin film relative to the total mass of the thermosetting resin film is either 10 to 65 mass% or 15 to 55 mass%,
The thermosetting resin film may have a content of the additive (I) of 0.5 to 10% by mass, 0.5 to 7% by mass, or 0.5 to 5% by mass relative to the total mass of the thermosetting resin film.

Manufacturing Method of Composite Sheet The composite sheet can be manufactured by laminating the above-mentioned layers in order so that they are in a corresponding positional relationship. The method for forming each layer is as described above.

For example, a composite sheet constructed by laminating a substrate, a buffer layer, an adhesive layer, and a thermosetting resin film in this order in the thickness direction can be produced by the method described below.
That is, a buffer layer is laminated on the substrate by extrusion molding a buffer layer-forming composition onto the substrate. The above-mentioned pressure-sensitive adhesive composition is applied to the release-treated surface of a release film, and dried as necessary to laminate a pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer on the release film is then bonded to the buffer layer on the substrate, thereby obtaining a laminated sheet with a release film, in which the substrate, buffer layer, pressure-sensitive adhesive layer, and release film are laminated in this order in the thickness direction.
Separately, the above-mentioned composition for forming a thermosetting resin film is applied to the release-treated surface of a release film, and dried as necessary to laminate a thermosetting resin film.
The release film is then removed from the laminated sheet obtained above, and the newly exposed surface of the pressure-sensitive adhesive layer is bonded to the exposed surface of the thermosetting resin film on the release film, thereby obtaining a composite sheet in which the substrate, buffer layer, pressure-sensitive adhesive layer, thermosetting resin film, and release film are laminated in this order in the thickness direction. The release film on the thermosetting resin film can be removed when the composite sheet is to be used.

Composite sheets comprising layers other than those described above can be produced by appropriately adding either or both of the formation process and lamination process of the other layers to the above-mentioned manufacturing method so that the lamination position of the other layers is appropriate.

◇Method for manufacturing semiconductor chips with first protective film (method for using thermosetting resin film and composite sheet)
As explained above, the thermosetting resin film of this embodiment has excellent properties in that, when applied to an uneven surface of an object, it can cover the entire uneven surface while penetrating the convex portions and exposing their upper portions. In other words, the thermosetting resin film of this embodiment is suitable for application to the uneven surface of an object having an uneven surface. Furthermore, if the uneven surface has fine grooves, the thermosetting resin film can sufficiently fill these grooves, thereby allowing the grooves to be sufficiently filled with the protective film. Furthermore, peeling of the protective film from the uneven surface can be suppressed.
The thermosetting resin film of this embodiment is particularly suitable for use in manufacturing a semiconductor chip with a first protective film, which includes, for example, a semiconductor chip and a first protective film provided on the side surface and the bump-bearing surface (bump-forming surface) of the semiconductor chip. In this case, the uneven surface is the bump-forming surface of the semiconductor chip, and the convex portions are the bumps. The concave portions include grooves on the bump-forming surface. The semiconductor chip with the first protective film is suitable for use in manufacturing a semiconductor device by flip-chip bonding the bumps therein to a substrate.
The thermosetting resin film of this embodiment is suitable for use in the form of the composite sheet described above.
A method for manufacturing a semiconductor chip with a first protective film when using the composite sheet will be described below.

A method for manufacturing a semiconductor chip with a first protective film according to one embodiment of the present invention is a method for manufacturing a semiconductor chip with a first protective film using a semiconductor wafer, wherein the semiconductor chip with the first protective film comprises a semiconductor chip and a first protective film provided on a side surface of the semiconductor chip and a surface having bumps, and the semiconductor wafer has bumps and grooves that become dividing points of the semiconductor wafer on one surface thereof, and the manufacturing method includes a bonding step of bonding the thermosetting resin film in the composite sheet according to one embodiment of the present invention to the one surface of the semiconductor wafer, thereby producing a semiconductor wafer with a thermosetting resin film that has the thermosetting resin film on the one surface and the grooves filled with the thermosetting resin film, and the manufacturing method further includes After the attaching step, a curing step (1) is performed in which the thermosetting resin film is thermally cured to form the first protective film, thereby producing a semiconductor wafer with a first protective film, the semiconductor wafer including the semiconductor wafer and the first protective film provided on the one surface of the semiconductor wafer and filling the grooves; after the curing step (1), a dividing step (1) is performed in which the semiconductor wafer is divided to produce a group of semiconductor chips with a first protective film, the group including a plurality of semiconductor chips and the first protective film provided on surfaces of the plurality of semiconductor chips having the bumps and in gaps between the semiconductor chips; and after the dividing step (1), the first protective film is cut along the gaps between the semiconductor chips in the group of semiconductor chips with a first protective film, thereby producing the semiconductor chips with a first protective film. a cutting step (2) of cutting the first protective film along the grooves in the semiconductor wafer with the first protective film to produce a cut-in first protective film-coated semiconductor wafer after the bonding step and after the curing step (1), and a dividing step (2) of dividing the semiconductor wafer after the cutting step (2) to produce the semiconductor chips with the first protective film (this manufacturing method in this case may be referred to as "manufacturing method (2)" in this specification); or a manufacturing method comprising: dividing the semiconductor wafer after the bonding step to produce a plurality of the semiconductor chips, and dividing the surfaces of the plurality of semiconductor chips having the bumps and the gaps between the semiconductor chips a curing step (3) of, after the dividing step (3), thermally curing the thermosetting resin film to form the first protective film, thereby producing a group of semiconductor chips with a first protective film, the group of semiconductor chips having a plurality of the semiconductor chips and the first protective film provided on the surfaces having the bumps of the plurality of semiconductor chips and in the gaps between the semiconductor chips; and a cutting step (3) of, after the curing step (3), cutting the first protective film along the gaps between the semiconductor chips in the group of semiconductor chips with a first protective film, to obtain the semiconductor chips with a first protective film (this manufacturing method may be referred to as "manufacturing method (3)" in this specification).
These manufacturing methods will be described below.

<<Manufacturing method (1)>>
4A to 4E are cross-sectional views that schematically show a manufacturing method (1) as an example of a method for manufacturing a semiconductor chip with a first protective film when the composite sheet 1 shown in FIG. 3 is used.
Here, since the thermosetting resin film is used to form the first protective film, the "composite sheet 1" is referred to as the "sheet 1 for forming the first protective film" and the "substrate 11" is referred to as the "first substrate 11".

<Attachment process>
In the bonding step of manufacturing method (1), as shown in Figures 4A to 4B, the thermosetting resin film 12 in the first protective film forming sheet 1 is bonded to one surface 9a of the semiconductor wafer 9 (hereinafter, sometimes referred to as the "bump forming surface").
The semiconductor wafer 9 has, on its bump-forming surface 9a, a plurality of bumps 91 and a plurality of grooves 90 which are to be the locations where the semiconductor wafer 9 is to be divided.
In this process, by providing a first protective film forming sheet 1 on the semiconductor wafer 9, a semiconductor wafer 901 with a thermosetting resin film is produced, in which the bump forming surface 9a of the semiconductor wafer 9 is provided with a thermosetting resin film 12 and the grooves 90 are filled with the thermosetting resin film 12.

Here, the top portion 9101 of the bump 91 is shown protruding from the thermosetting resin film 12. The degree to which the top portion 9101 of the bump 91 protrudes from the thermosetting resin film 12 can be adjusted by adjusting the composition and thickness of the thermosetting resin film 12 or the conditions for applying the resin film 12.

In the attachment step of manufacturing method (1), for example, as shown in Figure 4A, the first protective film forming sheet 1 is first positioned so that its thermosetting resin film 12 faces the bump formation surface 9a of the semiconductor wafer 9.

The thickness of the semiconductor wafer 9 to which the thermosetting resin film 12 is attached is not particularly limited, but is preferably 100 to 1000 μm, more preferably 200 to 900 μm, and even more preferably 300 to 800 μm. When the thickness of the semiconductor wafer 9 is equal to or greater than the lower limit, warping due to shrinkage during thermal curing of the thermosetting resin film 12 can be easily suppressed. When the thickness of the semiconductor wafer 9 is equal to or less than the upper limit, the time required for dividing the semiconductor wafer 9, which will be described later, can be further shortened.
In this specification, the "thickness of a semiconductor wafer" means the thickness of the semiconductor wafer in the region where the groove does not exist, when the semiconductor wafer has the groove.

The height of the bumps 91 is not particularly limited, but is preferably 120 to 300 μm, more preferably 150 to 270 μm, and particularly preferably 180 to 240 μm. When the height of the bumps 91 is equal to or greater than the lower limit, the function of the bumps 91 can be further improved. When the height of the bumps 91 is equal to or less than the upper limit, the effect of suppressing the thermosetting resin film 12 from remaining on the bumps 91 can be further improved.
In this specification, the "height of a bump" means the height of the bump at the highest point from the bump formation surface.

The width of the bump 91 is not particularly limited, but is preferably 170 to 350 μm, more preferably 200 to 320 μm, and particularly preferably 230 to 290 μm. When the width of the bump 91 is equal to or greater than the lower limit, the function of the bump 91 can be further improved. When the width of the bump 91 is equal to or less than the upper limit, the effect of suppressing the thermosetting resin film 12 from remaining on the bump 91 can be further improved.
In this specification, the "bump width" means the maximum length of a line segment obtained by connecting two different points on the bump surface when the bump is viewed in a plan view looking down on the bump from a direction perpendicular to the bump formation surface.

The distance between adjacent bumps 91 is not particularly limited, but is preferably 250 to 800 μm, more preferably 300 to 600 μm, and particularly preferably 350 to 500 μm. When the distance is equal to or greater than the lower limit, the function of the bumps 91 can be further improved. When the distance is equal to or less than the upper limit, the effect of suppressing the thermosetting resin film 12 from remaining on the bumps 91 can be further enhanced.
In this specification, the "distance between adjacent bumps" means the minimum distance between the surfaces of adjacent bumps.

The depth of the groove 90 is not particularly limited as long as it is equal to or greater than the final thickness of the semiconductor chip and less than the thickness of the semiconductor wafer 9 before grinding, which will be described later, but is preferably 30 to 700 μm, more preferably 60 to 600 μm, and even more preferably 100 to 500 μm. When the depth of the groove 90 is equal to or greater than the lower limit, it becomes easier to divide the semiconductor wafer 9, which will be described later. When the depth of the groove 90 is equal to or less than the upper limit, the semiconductor wafer 9 has a higher strength.
In this specification, when the groove depth is not a constant value, the maximum value of the groove depth is adopted as the "groove depth."

The width of the groove 90 is not particularly limited, but is preferably 10 to 2000 μm, more preferably 30 to 1000 μm, even more preferably 40 to 500 μm, and particularly preferably 50 to 300 μm. When the width of the groove 90 is equal to or greater than the lower limit, the effect of preventing contact between adjacent semiconductor chips when dividing the semiconductor wafer 9, as described below, is enhanced. When the width of the groove 90 is equal to or less than the upper limit, the semiconductor wafer 9 has a higher strength.
In this specification, when the groove width is not a constant value, the maximum value of the groove width is adopted as the "groove width."

Next, in the bonding step of manufacturing method (1), the thermosetting resin film 12 is brought into contact with the bumps 91 on the semiconductor wafer 9, and the first protective film-forming sheet 1 is pressed against the semiconductor wafer 9. This causes the first surface 12a of the thermosetting resin film 12 to be pressed against the surfaces 91a of the bumps 91 and the bump-forming surface 9a of the semiconductor wafer 9, successively. By heating the thermosetting resin film 12 at this time, the thermosetting resin film 12 softens and spreads between the bumps 91 so as to cover the bumps 91, adhering to the bump-forming surface 9a and covering the surfaces 91a of the bumps 91, particularly the surfaces 91a in the vicinity of the bump-forming surface 9a, thereby embedding the bases of the bumps 91. Therefore, the thermosetting resin film 12 is sufficiently adhered to the bump-forming surface 9a and the bases of the bumps 91, and the thermosetting resin film 12 is sufficiently filled into the grooves 90 on the semiconductor wafer 9.
As a result of the above, a semiconductor wafer 901 with a thermosetting resin film is obtained as shown in FIG. 4B.

As described above, the method of pressing the first protective film forming sheet 1 onto the semiconductor wafer 9 can be any known method of pressing various sheets onto an object to attach them, such as a method using a laminating roller.

The heating temperature of the first protective film forming sheet 1 (thermosetting resin film 12) when it is pressed onto the semiconductor wafer 9 may be a temperature at which the thermosetting resin film 12 does not undergo any or excessive thermal curing, and may be, for example, 80 to 100°C.
The heating temperature is preferably 85 to 95°C, since this will enhance the effect of the thermosetting resin film 12 being sufficiently adhered to the bump forming surface 9a and the base of the bump 91, and of the thermosetting resin film 12 being sufficiently filled into the groove 90.

The pressure when the first protective film forming sheet 1 (thermosetting resin film 12) is pressed onto the semiconductor wafer 9 is not particularly limited, and may be, for example, 0.1 to 1.5 MPa.
The pressure is preferably 0.3 to 1 MPa, since this will ensure that the thermosetting resin film 12 adheres sufficiently to the bump forming surface 9a and the base of the bump 91, and will enhance the effect of the thermosetting resin film 12 being sufficiently filled into the groove 90.

As described above, when the first protective film-forming sheet 1 is pressure-bonded to the semiconductor wafer 9, the thermosetting resin film 12, adhesive layer 14, and buffer layer 13 in the first protective film-forming sheet 1 are subjected to pressure from the bumps 91. Initially, the first surface 12a of the thermosetting resin film 12, the first surface 14a of the adhesive layer 14, and the first surface 13a of the buffer layer 13 are deformed concavely. The thermosetting resin film 12 may then tear if pressure is applied from the bumps 91 in this state. If the X value is 19 or greater but less than 10,000 (19≦X value<10,000), such tearing of the thermosetting resin film 12 occurs. In this case, when the first surface 12a of the thermosetting resin film 12 is finally pressure-bonded to the bump-forming surface 9a of the semiconductor wafer 9, the upper portion 910, including the apex 9101 of the bump 91, protrudes through the thermosetting resin film 12. In this final stage, the upper portion 910 of the bump 91 does not usually penetrate the buffer layer 13. This is because the buffer layer 13 has a buffering effect against the pressure applied by the bump 91.

Figure 4B shows a case where, at the stage when the attachment process is completed, no or almost no thermosetting resin film 12 remains on the upper part 910 including the top part 9101 of the bump 91, and the remaining thermosetting resin film 12 on the upper part 910 of the bump 91 is suppressed.
In this specification, unless otherwise specified, "almost no thermosetting resin film remains on top of the bump" means that although a small amount of thermosetting resin film remains on top of the bump, the remaining amount is such that it does not interfere with the electrical connection between the semiconductor chip and the substrate when the semiconductor chip equipped with this bump is flip-chip connected to the substrate.

When the X value is greater than or equal to 19 and less than 10,000, at the stage when the bonding process is completed, the thermosetting resin film 12 is prevented from protruding from its original size, thereby preventing the thermosetting resin film 12 from protruding from the bump-forming surface 9a of the semiconductor wafer 9.

When the X value is equal to or greater than 19 and less than 10,000, repelling of the thermosetting resin film 12 on the bump-forming surface 9a is further suppressed at the stage when the attachment process is completed. More specifically, with the thermosetting resin film 12 provided on the bump-forming surface 9a, the phenomenon in which areas of the bumps 91 other than their upper portions 910 (for example, the base portions near the bump-forming surface 9a) or areas of the bump-forming surface 9a near the bumps 91 are unintentionally exposed without being covered by the thermosetting resin film 12 is suppressed.

<Curing process (1)>
In the curing step (1) after the bonding step of the manufacturing method (1), the first support sheet 10 is removed from the semiconductor wafer 901 with the resin film, and then, as shown in Figure 4C, the thermosetting resin film 12 is thermally cured to form a first protective film 12', thereby producing a semiconductor wafer 902 with a first protective film, which includes the semiconductor wafer 9 and the first protective film 12' provided on the bump formation surface 9a of the semiconductor wafer 9 and filled in the grooves 90.
In the curing step (1), the thermosetting resin film 12 is heated and thermally cured under the heating conditions as described above.

The symbol 9b indicates the surface (back surface) opposite the bump-forming surface 9a of the semiconductor wafer 9.

If the adhesive layer 14 in the support sheet 10 is energy ray curable, the support sheet 10 can be more easily removed from the resin film-coated semiconductor wafer 901 by curing the adhesive layer 14.

In the semiconductor wafer 901 with a thermosetting resin film, the grooves 90 on the semiconductor wafer 9 are sufficiently filled with the thermosetting resin film 12, and thus the curing step (1) results in a semiconductor wafer 902 with a first protective film in which the grooves 90 are sufficiently filled with the first protective film 12'. Furthermore, in the semiconductor wafer 902 with a first protective film, the first protective film 12' is sufficiently adhered to the bump-forming surface 9a and the bases of the bumps 91, preventing peeling of the first protective film 12' from these surfaces.

<Dividing process (1)>
In the dividing step (1) after the hardening step (1), the semiconductor wafer 9 is divided to produce a group of semiconductor chips 903 with a first protective film, which includes a plurality of semiconductor chips 9′, surfaces 9a′ having bumps on the plurality of semiconductor chips 9′ (hereinafter, sometimes referred to as “bump-forming surfaces”), and a first protective film 12′ provided in the gaps 90′ between the semiconductor chips 9′, as shown in FIG. 4D.

The gap 90' between semiconductor chips 9' is the area sandwiched between the side surfaces 9c' of adjacent semiconductor chips 9'.

The semiconductor wafer 9 can be divided by known methods. In this embodiment, for example, this can be done by grinding the back surface 9b of the semiconductor wafer 9 using a grinding tool such as a grinder. The semiconductor wafer 9 is ground in the direction from the back surface 9b of the semiconductor wafer 9 toward the bump-forming surface 9a until the grinding surface (back surface 9b) reaches the groove 90 (in other words, until the groove 90 appears, or in other words, until the gap 90' is formed). In this way, the thickness of the semiconductor wafer 9 is reduced, and the groove 90 becomes the dividing point for dividing the semiconductor wafer 9. At the same time, the gap 90' is formed from the groove 90. Grinding of the back surface 9b of the semiconductor wafer 9 is continued until the thickness of the semiconductor chip 9' reaches the desired value. For example, grinding may be stopped when the grinding surface reaches the groove 90. Alternatively, the back surface 9b may be ground even after the grinding surface reaches the groove 90, along with the first protective film 12' present within the gap 90'.

In the division process (1), if necessary, backgrinding tape may be attached to the bump-forming surface 9a side of the semiconductor wafer 902 with the first protective film, and the back surface 9b of the semiconductor wafer 9 may be ground.

In this specification, for convenience, the back surface of the semiconductor wafer 9 being ground is also designated by the symbol 9b.
Reference numeral 9b' denotes the surface (back surface) of the semiconductor chip 9' opposite to the bump-formed surface 9a'.

In the group of semiconductor chips 903 with a first protective film, all of the semiconductor chips 9' are held together by a single first protective film 12'. When backgrind tape is used as described above, all of the semiconductor chips 9' are held together by a single first protective film 12' and the backgrind tape attached to the surface of the group of semiconductor chips 903 with a first protective film on the bump-forming surface 9a' side.

<Cutting process (1)>
In the cutting process (1) after the dividing process (1), the first protective film 12' is cut along the gaps 90' between the semiconductor chips 9' in the group of semiconductor chips 903 with the first protective film, thereby producing semiconductor chips 900 with the first protective film, as shown in Figure 4E.
The semiconductor chip 900 with a first protective film includes a semiconductor chip 9' and a first protective film 120' provided on a side surface 9c' and a bump-forming surface 9a' of the semiconductor chip 9'. The semiconductor chip 9' is protected on its side surface 9c' and bump-forming surface 9a' by the first protective film 120' after cutting, and the protection effect obtained for the semiconductor chip 9' is significantly high.

When the semiconductor chip 9' has a rectangular planar shape when viewed from above the bump-forming surface 9a', one semiconductor chip 9' has four side surfaces 9c'. Therefore, in the semiconductor chip 900 with a first protective film, the first protective film 120' after cutting is integrally provided on all (i.e., four) side surfaces 9c' of the semiconductor chip 9' and one bump-forming surface 9a'. In this specification, the "first protective film after cutting" may be simply referred to as the "first protective film."

In the cutting step (1), the first protective film 12' is cut along the outer periphery of the semiconductor chip 9' (in other words, the side surface 9c'). At this time, it is preferable to cut the first protective film 12' filling the gap 90' between adjacent semiconductor chips 9' along the outer periphery of the semiconductor chip 9' (in other words, the side surface 9c') and divide it into two pieces. By doing so, it is possible to provide a first protective film 120' with a more uniform shape after cutting on each side surface 9c' of the semiconductor chip 9'.

The first protective film 12' can be cut using known methods, such as blade dicing or laser dicing.

Cutting of the first protective film 12' can be performed, for example, by attaching a known dicing sheet to the back surface 9b' of the semiconductor chip 9' in the group of semiconductor chips 903 with the first protective film and removing the backgrinding tape. If the backgrinding tape has an energy ray-curable adhesive layer, the adhesive layer can be cured by irradiating it with energy rays, making it easier to remove the backgrinding tape from the group of semiconductor chips 903 with the first protective film.

In the semiconductor chip 900 with a first protective film, the first protective film 120' is sufficiently adhered to the bump-forming surface 9a', the base of the bump 91, and the side surface 9c' of the semiconductor chip 9', preventing the first protective film 120' from peeling off from these surfaces. Furthermore, a first protective film 120' of sufficient thickness is provided on the side surface 9c' of the semiconductor chip 9'.

Furthermore, when the X value is equal to or greater than 19 and less than 10,000, in the semiconductor chip 900 with the first protective film, the top 9101 of the bump 91 protrudes from the first protective film 120′, and the first protective film 120′ does not or hardly adheres to the upper portion 910 including the top 9101 of the bump 91, thereby suppressing adhesion of the first protective film 120′ to the upper portion 910 of the bump 91.
Furthermore, in the semiconductor chip 900 with the first protective film, the first protective film 120' is prevented from protruding from the bump-forming surface 9a' of the semiconductor chip 9'.
Furthermore, repelling of the first protective film 120' is suppressed on the bump-forming surface 9 a' of the semiconductor chip 9'. More specifically, with the first protective film 120' provided on the bump-forming surface 9 a', a phenomenon in which regions of the bumps 91 other than their upper portions 910 (for example, base portions near the bump-forming surface 9 a') or regions of the bump-forming surface 9 a' near the bumps 91 are unintentionally exposed without being covered by the first protective film 120' is suppressed.

<<Manufacturing method (2)>>
5A to 5E are cross-sectional views that schematically show a manufacturing method (2) as another example of a method for manufacturing a semiconductor chip with a first protective film when the composite sheet 1 shown in FIG. 3 is used.

<Attachment step, curing step (1)>
In the manufacturing method (2), as shown in FIGS. 5A to 5C, the bonding step and the curing step (1) are performed in the same manner as in the manufacturing method (1), to produce the semiconductor wafer 902 with the first protective film.

<Cutting process (2)>
In the cutting step (2) after the hardening step (1) of the manufacturing method (2), the first protective film 12' is cut along the grooves 90 in the semiconductor wafer 902 with the first protective film, thereby producing a cut semiconductor wafer 904 with the first protective film, as shown in Figure 5D.
In this step, it is preferable to cut the first protective film 12′ filled in the groove 90 along the side surface 90c of the groove 90. By doing so, it is possible to finally provide a first protective film with a more uniform shape after cutting on each side surface of the semiconductor chip.

In the cutting step (2), the first protective film 12' is cut from the surface 12b' opposite the semiconductor wafer 9 side of the first protective film 12' toward the surface 12a' facing the semiconductor wafer 9. At this time, the cuts in the first protective film 12' do not have to reach the tip of the first protective film 12' in the depth direction of the groove 90. However, in order to facilitate dividing the semiconductor wafer 9, as will be described later, it is preferable that the cuts be closer to the tip. It is more preferable that the cuts reach the tip, i.e., cut the first protective film 12'. Figure 5D shows a case where the cuts in the first protective film 12' reach the tip and cut the first protective film 12' (referred to as the first protective film 120' after cutting).
On the other hand, when the semiconductor wafer 9 is divided into semiconductor chips by grinding the back surface 9b of the semiconductor wafer 9 as described below, cracks or chips at the corners of the semiconductor chips and cracks or chips in the first protective film 12' present near the corners of the semiconductor chips are suppressed, so it is preferable that the reach position of the notch in the first protective film 12' coincides with the location where the back surface of the semiconductor chip is expected to be finally formed, or is near such a location.

The first protective film 12' can be cut using known methods such as blade dicing or laser dicing, as in the cutting process (1) above.

<Dividing process (2)>
In the dividing step (2) after the cutting step (2), the semiconductor wafer 9 is divided to produce semiconductor chips 900 with a first protective film, as shown in FIG. 5E.
The semiconductor chips 900 with the first protective film obtained in the dividing step (2) are the same as the semiconductor chips 900 with the first protective film obtained in the cutting step (1).

The semiconductor wafer 9 can be divided by a known method, similar to the case of the dividing step (1).
For example, when the back surface 9b of the semiconductor wafer 9 is ground using a grinding means such as a grinder, the back surface 9b is ground in a direction from the back surface 9b toward the bump-forming surface 9a until the ground surface (back surface 9b) reaches the groove 90. If, in the cutting step (2), the notch in the first protective film 12′ does not reach the tip of the first protective film 12′ in the depth direction of the groove 90, the back surface 9b is further ground together with the first protective film 12′ until the ground surface reaches the notch in the first protective film 12′.

As in manufacturing method (1), in the semiconductor chip 900 with the first protective film obtained in dividing step (2), peeling of the first protective film 120' from the bump-forming surface 9a', the base of the bumps 91, and the side surfaces 9c' of the semiconductor chip 9' is suppressed. Furthermore, a first protective film 120' of sufficient thickness is provided on the side surfaces 9c' of the semiconductor chip 9'.

Furthermore, when the X value is greater than or equal to 19 and less than 10,000, as in the case of manufacturing method (1), the semiconductor chip 900 with the first protective film obtained in the division process (2) has the following effects: suppression of adhesion of the first protective film 120' to the upper part 910 of the bump 91; suppression of overflow of the first protective film 120' from the bump formation surface 9a'; and suppression of repelling of the first protective film 120' from the bump formation surface 9a'.

<<Manufacturing method (3)>>
6A to 6E are cross-sectional views that schematically show a manufacturing method (3) as yet another example of a method for manufacturing a semiconductor chip with a first protective film when the composite sheet 1 shown in FIG. 3 is used.

<Attachment process>
In the manufacturing method (3), as shown in FIGS. 6A and 6B, the bonding step is carried out in the same manner as in the manufacturing method (1), and the semiconductor wafer 901 with the thermosetting resin film is produced.

<Dividing process (3)>
In the dividing step (3) after the bonding step of the manufacturing method (3), the semiconductor wafer 9 is divided to produce a group of semiconductor chips 905 with a thermosetting resin film, which includes a plurality of semiconductor chips 9′ and a thermosetting resin film 12 provided on the bump-forming surfaces 9a′ of the plurality of semiconductor chips 9′ and in the gaps 90′ between the semiconductor chips 9′, as shown in FIG. 6C.

The semiconductor wafer 9 can be divided using known methods, as in the division step (1) above.

In the group of semiconductor chips with thermosetting resin film 905, all of the semiconductor chips 9' are held together by a single thermosetting resin film 12 and a support sheet 10.

<Curing step (3)>
In the curing process (3) after the dividing process (3), the first support sheet 10 is removed from the semiconductor chip group 905, and then the thermosetting resin film 12 is thermally cured to form a first protective film, thereby producing a semiconductor chip group 903 with a first protective film, which includes a plurality of semiconductor chips 9' and a first protective film 12' provided on the bump forming surfaces 9a' of the plurality of semiconductor chips 9' and in the gaps 90' between the semiconductor chips 9', as shown in Figure 6D.
The group of semiconductor chips 903 with a first protective film obtained in the curing step (3) is the same as the group of semiconductor chips 903 with a first protective film obtained in the dividing step (1).

Thermosetting of the thermosetting resin film 12 can be carried out by known methods, as in the curing step (1) above.

<Cutting process (3)>
In the cutting process (3) after the hardening process (3), the first protective film 12' is cut along the gaps 90' between the semiconductor chips 9' in the group 903 of semiconductor chips with the first protective film, thereby producing semiconductor chips 900 with the first protective film.
The semiconductor chips 900 with the first protective film obtained in the cutting step (3) are the same as the semiconductor chips 900 with the first protective film obtained in the cutting step (1).

Cutting of the first protective film 12' can be carried out using known methods, as in the cutting process (1) above.

As in manufacturing method (1), in the semiconductor chip 900 with the first protective film obtained in cutting step (3), peeling of the first protective film 120' from the bump-forming surface 9a', the bases of the bumps 91, and the side surfaces 9c' of the semiconductor chip 9' is suppressed. Furthermore, a first protective film 120' of sufficient thickness is provided on the side surfaces 9c' of the semiconductor chip 9'.

Furthermore, when the X value is greater than or equal to 19 and less than 10,000, as in the case of manufacturing method (1), the semiconductor chip 900 with the first protective film obtained in cutting process (3) has the following effects: suppression of adhesion of the first protective film 120' to the upper part 910 of the bump 91; suppression of protrusion of the first protective film 120' from the bump forming surface 9a'; and suppression of repelling of the first protective film 120' from the bump forming surface 9a'.

So far, we have explained the use of the composite sheet (sheet for forming the first protective film) 1 shown in Figure 3, but even when using the composite sheet of the other embodiments described above, this composite sheet will achieve the same effects as when using composite sheet 1.

The above-mentioned manufacturing methods (1) to (3) may include other steps different from those described above, as long as they do not deviate from the spirit of the present invention.

For example, when a second protective film is provided on the back surface of a semiconductor chip, manufacturing methods (1) to (3) may, at any time, include a step of attaching a second protective film-forming film in a second protective film-forming sheet to the back surface of the semiconductor chip, a step of curing the second protective film-forming film to form a second protective film if the second protective film-forming film is curable, and a step of cutting the second protective film-forming film or the second protective film along the outer periphery (side) of the semiconductor chip.

For example, if the curable resin film 12, the first protective film 12', or the first protective film 120' after cutting remains on the upper portion 910 including the top portion 9101 of the bump 91 at any stage after the bonding process, manufacturing methods (1) to (3) may include a removal process of removing the remaining curable resin film 12, the first protective film 12', or the first protective film 120' after cutting from the upper portion 910 of the bump 91 at any time after the bonding process.

Any remaining thermosetting resin film 12, first protective film 12', or first protective film 120' after cutting on the upper part 910 of the bump 91 can be removed by known methods, such as plasma irradiation.

So far, we have described the application of a support sheet or backgrinding tape to the bump-forming surface of a semiconductor wafer or the bump-forming surface of a semiconductor chip group via a thermosetting resin film or a first protective film to perform grinding of the backside of the semiconductor wafer or the backside of a semiconductor chip group. However, in this embodiment, instead of the support sheet or backgrinding tape, a resin sheet other than these may be applied to perform grinding of the backside of the semiconductor wafer or the backside of a semiconductor chip group. Here, the resin sheet can be formed by embedding a thermosetting resin film or a first protective film on the bump-forming surface of the semiconductor wafer or the bump-forming surface of the semiconductor chip group using a flowable resin, further embedding the surfaces of the bumps, and then thermally curing the resin. When providing such a resin sheet, a resin film covering the thermosetting resin film or first protective film on the bump-forming surface and the surface of the bumps may be formed using another resin that is flexible enough to conform to the surfaces of the bumps before applying the flowable resin. The resin sheet may then be applied via this resin film. By providing the resin film in this manner, the resin sheet can be easily removed after grinding or the like of the rear surface of the semiconductor wafer or the rear surface of the semiconductor chip group.

A semiconductor device can be manufactured by using the semiconductor chip with the first protective film. For example, the semiconductor chip with the first protective film is flip-chip connected (mounted) to the circuit formation surface of a circuit board at the tops of the bumps therein.
When a sheet for forming a second protective film is used, prior to flip-chip connection of the semiconductor chip with the first protective film, the semiconductor chip with the first protective film and the second protective film is separated from the dicing sheet in the sheet for forming a second protective film and picked up.
The semiconductor chip with the first protective film and the second protective film can be picked up by a known method.

Then, using the circuit board thus obtained and already equipped with the semiconductor chip, a semiconductor package is produced according to a known method, and the desired semiconductor device can be manufactured using this semiconductor package.

The present invention will be described in more detail below with reference to specific examples. However, the present invention is not limited to the examples shown below.

<Raw materials for producing thermosetting resin film-forming composition>
The raw materials used in the production of the thermosetting resin film-forming composition are shown below.
[Polymer component (A)]
(A)-1: Polyvinyl butyral having structural units represented by the following formulas (i)-1, (i)-2, and (i)-3 ("S-LEC (registered trademark) BL-10" manufactured by Sekisui Chemical Co., Ltd., weight average molecular weight 25,000, glass transition temperature 59°C).
(A)-2: Polyvinyl butyral having structural units represented by the following formulas (i)-1, (i)-2, and (i)-3 ("S-LEC (registered trademark) BL-2" manufactured by Sekisui Chemical Co., Ltd., weight average molecular weight 50,000, glass transition temperature 68°C).

[Epoxy resin (B1)]
(B1)-1: Liquid modified bisphenol A epoxy resin (manufactured by DIC Corporation, "Epiclon EXA-4850-150", molecular weight 900, epoxy equivalent 450 g/eq)
(B1)-2: Dicyclopentadiene-type epoxy resin (DIC Corporation, "Epicron HP-7200HH", epoxy equivalent: 254 to 264 g/eq)
[Thermal curing agent (B2)]
(B2)-1: Novolac-type phenolic resin curing agent (DIC Corporation, "Phenolite KA-1160")
[Curing accelerator (C)]
(C)-1: 2-phenyl-4,5-dihydroxymethylimidazole, "Curesol 2PHZ-PW" manufactured by Shikoku Chemicals Corporation (powder at room temperature)
(C)-2: 1-benzyl-2-methylimidazole, "Curesol 1B2MZ" (liquid at room temperature) manufactured by Shikoku Chemicals Corporation
[Filler (D)]
(D)-1: Spherical silica modified with epoxy groups ("Admanano YA050C-MKK" manufactured by Admatechs Co., Ltd., average particle size 50 nm)
[Additive (I)]
(I)-1: Surfactant (acrylic polymer, "BYK-361N" manufactured by BYK Corporation)
(I)-2: Silicone oil (aralkyl-modified silicone oil, "XF42-334" manufactured by Momentive Performance Materials Japan, Inc.)

[Example 1]
<<Production of Thermosetting Resin Film and Sheet for Forming First Protective Film>>
<Production of Thermosetting Resin Film-Forming Composition>
Polymer component (A)-1 (100 parts by mass), epoxy resin (B1)-1 (290 parts by mass), epoxy resin (B1)-2 (220 parts by mass), (B2)-1 (160 parts by mass), curing accelerator (C)-1 (2 parts by mass), filler (D)-1 (200 parts by mass), additive (I)-1 (25 parts by mass), and additive (I)-2 (3 parts by mass) were dissolved or dispersed in methyl ethyl ketone and stirred at 23°C to obtain composition (III) as a thermosetting resin film-forming composition, in which the total concentration of all components other than the solvent was 45% by mass. Note that the blending amounts of all components other than the solvent shown here are the blending amounts of the target product excluding the solvent.

<Production of Thermosetting Resin Film>
A release film ("SP-PET381031" manufactured by Lintec Corporation, thickness 38 μm) made of polyethylene terephthalate, one side of which had been subjected to a silicone treatment for release, was used, and the composition (III) obtained above was applied to the release-treated surface, followed by heating and drying at 120°C for 2 minutes, thereby forming a thermosetting resin film having a thickness of 45 μm.

<Production of Sheet for Forming First Protective Film>
A laminate sheet (backgrind tape, layer thickness: 510 μm, manufactured by Lintec Corporation, "E-8510HR"; also corresponding to the support sheet) corresponding to a laminate of a first substrate (thickness: 160 μm), a buffer layer (thickness: 300 μm), and a first adhesive layer (thickness: 50 μm) was used, and the first adhesive layer in this laminate sheet was bonded to the thermosetting resin film on the release film obtained above. This resulted in a first protective film-forming sheet having the configuration shown in FIG. 3, in which the first substrate, buffer layer, first adhesive layer, thermosetting resin film, and release film were laminated in this order in the thickness direction.

<<Evaluation of Thermosetting Resin Films>>
[Production of thermosetting resin film and first test piece]
Twenty 50 μm-thick thermosetting resin films were prepared in the same manner as above, except that the coating amount of composition (III) was changed. These 20 thermosetting resin films were laminated together, and the resulting laminated film was cut into a 10 mm × 10 mm square to prepare a first test piece of a 1 mm-thick thermosetting resin film.

[Measurement of gel time of thermosetting resin film]
The stainless steel plate of the indented sample holder of the automatic curing time measuring device "Madoka" (manufactured by Cyber Corporation, model number: MDK4G-02SP) was heated to 180°C in advance.
A first test piece measuring 10 mm x 10 mm and 1 mm thick was placed on a stainless steel plate heated to 180°C in the recessed sample holder of the "Madoka" automatic curing time measuring device. The thermosetting resin film immediately melted and turned into a liquid. Simultaneously with the placement of the first test piece, the stirring blades installed at a distance above the stainless steel plate began to rotate. The stainless steel plate was then raised to the gap position specified below over 15 seconds so that the stirring blades would come into contact with the thermosetting resin, which had turned into a liquid thermosetting resin film. The stirring blades were rotated under the heating and stirring conditions specified below, and the thermosetting resin was continuously stirred while measuring the stirring blade torque. The stirring blade torque increased over time. The gelation time was measured as the time (s) from the time the first test piece was placed on the stainless steel plate to the time the stirring blade torque reached 2.5 gf cm. The heating and stirring conditions were as follows:

(Conditions for heating and stirring)
・Stirring blade: screw stirring rod ・Stirring blade model number: 5TC-72890
Rotation speed of stirring blade: 100 rpm
Rotation speed of stirring blade: 40 rpm
Gap (distance between heated stainless steel plate and stirring blade): 0.3 mm
・Stainless steel plate heating setting temperature: 180℃

<Evaluation of Thermosetting Resin Film's Suitability for Filling Grooves on Wafer Surface>
[Fabrication of Silicon Wafer with First Protective Film]
Using a half-cut dicer (DISCO Corporation, "DFD6361"), multiple grooves, each 60 μm wide and 230 μm deep, were formed in a mesh pattern on the surface of a silicon wafer (12 inches in diameter, 750 μm thick) to obtain chips measuring 6 mm x 6 mm.
Using a laminating device (roller type laminator, "RAD-3510 F/12" manufactured by Lintec Corporation), the sheet for forming the first protective film obtained above was laminated to the surface of the silicon wafer on which the grooves were formed, using the thermosetting resin film therein, under conditions of a table temperature of 90°C, an laminating speed of 2 mm/s, an laminating pressure of 0.5 MPa, and a roller laminating height of -200 μm.
Next, the laminated sheet (support sheet) was peeled off from the first protective film-forming sheet to prepare a silicon wafer with a thermosetting resin film.
Next, this thermosetting resin film, after being attached to the surface of the silicon wafer on which the grooves were formed, was heat-treated using a pressure oven ("RAD-9100" manufactured by Lintec Corporation) under heating conditions of a temperature of 130°C, a time of 4 hours, and an oven pressure of 0.5 MPa, thereby thermally curing the film and forming a first protective film.
In this manner, a silicon wafer with a first protective film was produced.

[Evaluation of Thermosetting Resin Film's Suitability for Filling Grooves on Wafer Surface]
The silicon wafers with the first protective film obtained above were observed using an optical microscope. The suitability of the first protective film (i.e., the cured product of the thermosetting resin film) for filling grooves on the wafer surface was evaluated according to the following criteria. The results are shown in the "Groove Filling Suitability" column in Table 1.
(Evaluation criteria)
A: No distortion was observed in the shape of the first protective film, and the film had high suitability for filling grooves.
B: The shape of the first protective film is slightly distorted in the area near the opening of the groove, but the groove filling suitability is good.
C: Not corresponding to either A or B above, and the groove filling suitability is poor.

<Evaluation of the effect of preventing peeling of the first protective film from the side surface of the chip>
[Production of Silicon Chip with First Protective Film]
Again, a laminate sheet (backgrind tape, "E-8510HR" manufactured by Lintec Corporation) corresponding to a laminate of the first substrate, the buffer layer, and the first adhesive layer was used, and the first adhesive layer in this laminate sheet was bonded to the surface of the first protective film of the silicon wafer with the first protective film for which the filling suitability had been evaluated. The back surface of the silicon wafer with the first protective film was ground until the ground surface reached the grooves, dividing the silicon wafer into silicon chips, and grinding was continued until the thickness of the silicon chips was 200 μm.
Next, using a laminating device (roller type laminator, "RAD-3510 F/12" manufactured by Lintec Corporation), dicing tape ("D-686H" manufactured by Lintec Corporation) was attached to the back surface (ground surface) of all of the silicon chips obtained above. Then, using a blade dicer ("DFD6362" manufactured by DISCO Corporation), the first protective film was cut along the periphery of the obtained silicon chip by blade dicing. At this time, the blade movement speed was set to 10 mm/s, the blade rotation speed was set to 50,000 rpm, and the dicing tape substrate was cut with the blade to a depth of 20 μm from the surface on the silicon chip side.
As a result of the above, a plurality of silicon chips with a first protective film were obtained, each comprising a silicon chip measuring 6 mm x 6 mm and a first protective film integrally formed on four side surfaces and one surface (the surface that had the groove in the silicon wafer) of the silicon chip, and fixed on dicing tape.

[Evaluation of the effect of preventing peeling of the first protective film from the side surface of the chip]
Next, the silicon chips with the first protective film were picked up by separating them from the dicing tape from a location corresponding to the central portion of the silicon wafer and four locations near the peripheral edge of the silicon wafer that were approximately equidistant from the central portion and equidistant from each other. The sides of the five silicon chips with the first protective film thus obtained were observed using an optical microscope. The number of silicon chips with the first protective film in which peeling of the first protective film was observed on at least one of the four sides (number of defective products) was then determined. The results of "number of defective products/number of evaluations (=5)" are shown in the "Peeling Inhibition Effect" column in Table 1.

<Measurement of Gc1 and Gc300 of Thermosetting Resin Film and Calculation of X Value>
[Production of thermosetting resin film and second test piece]
Twenty 50 μm-thick thermosetting resin films were prepared in the same manner as above, except that the coating amount of composition (III) was changed. These thermosetting resin films were then laminated, and the resulting laminated film was cut into a disk shape with a diameter of 25 mm to prepare a second test piece of the thermosetting resin film with a thickness of 1 mm.

[Measurement of Gc1 and Gc300 of thermosetting resin film and calculation of X value]
The location where the test piece was to be placed in the viscoelasticity measuring device ("MCR301" manufactured by Anton Paar) was kept warm at 90°C in advance, and the second test piece of the thermosetting resin film obtained above was placed on this location, and the measuring jig was pressed against the top surface of this second test piece to fix the second test piece to the location.
Next, under the conditions of a temperature of 90°C and a measurement frequency of 1 Hz, the strain generated in the second test piece was increased stepwise in the range of 0.01% to 1000%, and the storage modulus Gc of the second test piece was measured. Then, the X value was calculated from the measured values of Gc1 and Gc300. The results are shown in Table 1.

<Measurement of protrusion amount of thermosetting resin film>
[Production of thermosetting resin film and third test piece]
A release film ("SP-PET381031" manufactured by Lintec Corporation, thickness 38 μm) made of polyethylene terephthalate, one side of which had been subjected to a silicone treatment for release, was used, and the composition (III) obtained above was applied to the release-treated surface, followed by heating and drying at 120°C for 2 minutes, thereby forming a thermosetting resin film having a thickness of 30 μm.
Next, this thermosetting resin film was processed together with the release film into a circular shape having a diameter of 170 mm to prepare a third test piece with a release film.

[Measurement of protrusion amount of thermosetting resin film]
The entire exposed surface of the obtained third test piece (in other words, the surface opposite to the side provided with the release film) was bonded to the surface of a transparent strip-shaped backgrind tape ("E-8180" manufactured by Lintec Corporation) to obtain the laminate shown in Figure 7. Figure 7 is a plan view schematically showing the state of the obtained laminate when viewed from above the backgrind tape side.
As shown here, the obtained laminate 101 is composed of a backgrind tape 7, a third test piece 120 (thermosetting resin film 12), and a release film laminated in this order in the thickness direction.

Next, the release film was removed from the resulting laminate, and the newly exposed surface of the third test piece (in other words, the surface of the third test piece opposite the side provided with the backgrind tape) was pressed against one surface of a 12-inch diameter silicon wafer, thereby attaching the third test piece to the surface of the silicon wafer. At this time, the third test piece was attached while being heated using a laminating device (a roller-type laminator, "RAD-3510 F/12" manufactured by Lintec Corporation) under conditions of a table temperature of 90°C, an attachment speed of 2 mm/s, an attachment pressure of 0.5 MPa, and a roller attachment height of -200 μm.
Next, for the third test piece with the backgrind tape attached to the silicon wafer, the maximum length of the line segment connecting two different points on the periphery was measured, and the measured value (maximum length of the line segment) was used to calculate the protrusion amount (mm) of the third test piece (in other words, the thermosetting resin film) by the method described with reference to Figure 2. The results are shown in Table 1.

[Reference examples 1-2]
<<Production of Thermosetting Resin Film and Sheet for Forming First Protective Film, and Evaluation of Thermosetting Resin Film>>
A thermosetting resin film and a first protective film-forming sheet were produced and the thermosetting resin film was evaluated in the same manner as in Example 1, except that either or both of the types and amounts of the components were changed during production of the thermosetting resin film-forming composition so that the types and contents of the components contained in the thermosetting resin film-forming composition were as shown in Table 1. The results are shown in Table 1.
In Table 1, the notation "-" in the column for contained components means that the thermosetting resin film-forming composition does not contain that component.

As is clear from the above results, in Example 1, the thermosetting resin film had good suitability for filling grooves on the silicon wafer surface. Furthermore, in Example 1, no peeling of the first protective film was observed on the four side surfaces of the semiconductor chip with the first protective film, and naturally no chipping of the first protective film was observed, significantly suppressing peeling of the first protective film from the side surfaces of the silicon chip. In Example 1, no peeling of the first protective film was observed on the side surfaces of the silicon chip (the surfaces that had the silicon wafer grooves), and naturally no chipping of the first protective film was observed, significantly suppressing peeling of the first protective film from the side surfaces. In Example 1, the gelation time of the thermosetting resin film at 180°C was 300 seconds or more.

In Example 1, the protrusion amount of the third test piece was 0 mm (no protrusion of the thermosetting resin film was observed), and the basic properties of this thermosetting resin film were good.
Furthermore, in Example 1, the X value was 65, and it was determined that the thermosetting resin film of Example 1, when attached to an uneven surface (e.g., a bump-formed surface of a semiconductor wafer), can penetrate convex portions (e.g., bumps), can prevent the film from remaining at the top of the convex portions, can prevent the film from protruding from the uneven surface, and can prevent the thermosetting resin film itself and its cured product from repelling on the uneven surface.

In contrast, in Reference Example 1, although the thermosetting resin film had good suitability for filling grooves on the silicon wafer surface, peeling of the first protective film was observed on one of the four side surfaces of the semiconductor chip with the first protective film. In Reference Example 1, the gel time of the thermosetting resin film at 180°C was 299 seconds.
Furthermore, in Reference Example 2, when the thermosetting resin film was applied, air bubbles remained inside the groove, and because the gelling time was short, the protective film was thermally cured before the air bubbles could be removed, resulting in the existence of unprotected areas, which confirmed that the film had less desirable characteristics in terms of its suitability for filling the above-mentioned grooves and preventing the first protective film from peeling off from the side of the silicon chip.

The present invention can be used in the manufacture of semiconductor chips and the like having bumps on their connection pads, which are used in flip-chip connection methods.

DESCRIPTION OF SYMBOLS 1... Composite sheet (sheet for forming first protective film), 10... Support sheet (first support sheet), 10a... One side of support sheet, 11... Base material (first base material), 11a... One side of base material, 12... Thermosetting resin film, 12a... First side of thermosetting resin film, 12'... First protective film, 120'... First protective film (first protective film after cutting), 13... Buffer layer, 9... Semiconductor wafer, 90... Groove of semiconductor wafer, 9a... Bump-forming surface of semiconductor wafer, 9'... Semiconductor chip, 9a'... Bump-forming surface of semiconductor chip, 9c'... Side of semiconductor chip, 91... Bump, 900... Semiconductor chip with first protective film, 901... Semiconductor wafer with thermosetting resin film, 902... Semiconductor wafer with first protective film, 903... Group of semiconductor chips with first protective film, 904... Semiconductor wafer with cut-out first protective film, 905... Group of semiconductor chips with thermosetting resin film

Claims (7)

A thermosetting resin film,
A thermosetting resin film measuring 10 mm x 10 mm x 1 mm was used as a first test piece, and when the first test piece was placed on a stainless steel plate heated to 180°C in a recessed sample holder of an automatic curing time measuring device "Madoka," and the mixture was heated and stirred under the following conditions, the gelation time was 300 seconds or more from the time when the torque of the stirring blade reached 2.5 gf cm:
the thermosetting resin film contains a polymer component (A), an epoxy resin (B1), and an additive (I),
the polymer component (A) is polyvinyl acetal,
The additive (I) contains a surfactant and a silicone oil,
The content ratio of the additive (I) in the thermosetting resin film relative to the total mass of the thermosetting resin film is 0.5 to 10 mass%,
(Conditions for heating and stirring)
・Stirring blade: screw stirring rod ・Stirring blade model number: 5TC-72890
Rotation speed of stirring blade: 100 rpm
Rotation speed of stirring blade: 40 rpm
Distance between heated stainless steel plate and stirring blade: 0.3 mm
・Stainless steel plate heating setting temperature: 180℃
A thermosetting resin film having a diameter of 25 mm and a thickness of 1 mm was used as a second test piece, and strain was generated in the second test piece under conditions of a temperature of 90°C and a frequency of 1 Hz to measure the storage elastic modulus of the second test piece. When the storage elastic modulus of the second test piece when the strain of the second test piece is 1% is defined as Gc1, and the storage elastic modulus of the second test piece when the strain of the second test piece is 300% is defined as Gc300, the following formula was obtained:
X=Gc1/Gc300
The thermosetting resin film has an X value calculated by the above formula: The thermosetting resin film according to claim 1, wherein the thermosetting resin film is intended for application to an uneven surface. The thermosetting resin film according to claim 1, wherein the thermosetting resin film is used to protect the uneven surface and side surfaces of a semiconductor chip. A support sheet and a resin film provided on one surface of the support sheet,
A composite sheet, wherein the resin film is the thermosetting resin film according to any one of claims 1 to 3 . 5. The composite sheet according to claim 4, wherein the support sheet comprises a substrate and an adhesive layer provided on one surface of the substrate, the adhesive layer being disposed between the substrate and the resin film. 5. The composite sheet according to claim 4, wherein the support sheet comprises a substrate and a buffer layer provided on one surface of the substrate, the buffer layer being disposed between the substrate and the thermosetting resin film. A method for manufacturing a semiconductor chip with a first protective film using a semiconductor wafer, comprising:
The semiconductor chip with a first protective film includes a semiconductor chip and a first protective film provided on a side surface of the semiconductor chip and a surface having bumps,
the semiconductor wafer has, on one surface thereof, bumps and grooves that become dividing portions of the semiconductor wafer;
The manufacturing method includes a bonding step of bonding the thermosetting resin film in the composite sheet according to any one of claims 4 to 6 to the one surface of the semiconductor wafer, thereby producing a semiconductor wafer with a thermosetting resin film, in which the one surface is provided with the thermosetting resin film and the grooves are filled with the thermosetting resin film;
The manufacturing method further comprises:
a curing step (1) of curing the thermosetting resin film after the attaching step to form the first protective film, thereby producing a semiconductor wafer with a first protective film, the semiconductor wafer including the semiconductor wafer and the first protective film provided on the one surface of the semiconductor wafer and filling the grooves; a dividing step (1) of dividing the semiconductor wafer after the curing step (1) to produce a group of semiconductor chips with a first protective film, the group including a plurality of semiconductor chips and the first protective film provided on surfaces of the plurality of semiconductor chips having the bumps and in gaps between the semiconductor chips; and a cutting step (1) of cutting the first protective film along the gaps between the semiconductor chips in the group of semiconductor chips with a first protective film, after the dividing step (1), to produce the semiconductor chips with a first protective film;
a cutting step (2) of cutting the first protective film along the grooves in the semiconductor wafer with the first protective film after the bonding step and the curing step (1) to produce a cut-in semiconductor wafer with the first protective film, and a dividing step (2) of dividing the semiconductor wafer after the cutting step (2) to produce semiconductor chips with the first protective film, or
a dividing step (3) of dividing the semiconductor wafer after the bonding step to produce a group of semiconductor chips with a thermosetting resin film, the group including a plurality of semiconductor chips and the thermosetting resin film provided on the surfaces of the plurality of semiconductor chips having the bumps and in the gaps between the semiconductor chips; a curing step (3) of thermally curing the thermosetting resin film after the dividing step (3) to form the first protective film, thereby producing a group of semiconductor chips with a first protective film, the group including a plurality of semiconductor chips and the first protective film provided on the surfaces of the plurality of semiconductor chips having the bumps and in the gaps between the semiconductor chips; and a cutting step (3) of cutting the first protective film along the gaps between the semiconductor chips in the group of semiconductor chips with a first protective film after the curing step (3), to obtain the semiconductor chips with a first protective film.