JP7789658B2 - Resin film, composite sheet, and method for manufacturing semiconductor device - Google Patents

Description

The present invention relates to a resin film, a composite sheet, and a method for manufacturing a semiconductor device.
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 curable 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 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.
To form the protective film, a protective film formation sheet 8 as shown in Fig. 8A is used. The protective film formation sheet 8 is configured by laminating a buffer layer 83 and a curable resin film 82 in this order on a substrate 81. The buffer layer 83 has a buffering effect against forces applied to the buffer layer 83 and adjacent layers.

First, the protective film forming sheet 8 is placed so that the curable resin film 82 faces the bump formation 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 curable 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 curable resin film 82 at this time is performed while heating the curable resin film 82. As a result, the curable 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, but if the bumps 91 penetrate the curable resin film 82, the buffer layer 83 is also in close contact with part of the surfaces 91a of the bumps 91.
After bonding such a curable resin film 82, if necessary, the surface (back surface) 9b of the semiconductor wafer 9 opposite the bump formation 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 substrate 81 and the buffer layer 83 are removed from the curable resin film 82.
The curable resin film 82 is then cured to form a protective film 82' as shown in FIG. 8D.

In this protective film formation method, it is necessary for the upper portion 910 of the bump 91 to protrude through the protective film 82'. To achieve this, it is important that, as described above, when the substrate 81 and buffer layer 83 are peeled off, the upper portion 910 of the bump 91 protrudes through the curable resin film 82, with no curable resin film 82 remaining on the upper portion 910 of the bump 91. Conversely, Figure 9 shows an example of a state in which the curable resin film 82 remains on the upper portion 910 of the bump 91. Here, an example is shown in which the entire surface 91a of the bump 91 is covered with the curable resin film 82. However, this is only one example of a state in which the curable resin film 82 remains; for example, in some cases, a portion of the surface 91a of the upper portion 910 of the bump 91 is exposed and not covered by the curable resin film 82.

As such, a protective film forming sheet capable of forming a protective film without leaving any curable resin film remaining on top of the bumps has been disclosed, which is configured so that when a 300% strain is generated in the buffer layer under conditions of a temperature of 90°C and a frequency of 1 Hz, the shear modulus of the buffer layer is equal to or greater than the shear modulus of the curable resin film when a 300% strain is generated in the curable resin film under the same conditions (see Patent Document 1).

Japanese Patent No. 6344811

On the other hand, as explained above, when the protective film forming sheet is attached to the bump-forming surface of the semiconductor wafer using the curable resin film while the curable resin film in the protective film forming sheet is heated (for example, the stage shown in Figure 8B), the width of the curable resin film increases compared to the stage before attachment, and the curable resin film may protrude from its original size. Such protrusion is likely to occur with curable resin films that can prevent the film from remaining on the top of the bumps, as described above. If protrusion of the curable resin film occurs in this way, various equipment used in subsequent processes involving handling the semiconductor wafer or the semiconductor chips obtained by dividing the semiconductor wafer may be contaminated by the adhesion of the protruding curable resin film. However, no conventional protective film forming sheets have been designed to prevent such protrusion of the curable resin film.

So far, we have used the example of applying a curable resin film to the bump-formed surface of a semiconductor wafer as an explanation, but this is not limited to curable resin films; resin films may also be applied to uneven surfaces other than the bump-formed surface of a semiconductor wafer. Furthermore, just as with the upper portions of bumps, it may be necessary to prevent the resin film from remaining on the tops of the convex parts of the uneven surface. However, when applying a film to such uneven surfaces in general, there is a possibility that the resin film may overflow.

The present invention aims to provide a resin film that can be applied to an uneven surface, which, when applied to the uneven surface, can penetrate the convex parts, can prevent the convex parts from remaining at the top, and can prevent the film from protruding from its original size, and a composite sheet comprising the resin film that is used when applying the resin film to an uneven surface.

The present invention relates to a resin film, wherein strain is generated in a test piece of the resin film having a diameter of 25 mm and a thickness of 1 mm under conditions of a temperature of 90°C and a frequency of 1 Hz, and the storage modulus of the test piece is measured, and when the storage modulus of the test piece when the strain of the test piece is 1% is defined as Gc1 and the storage modulus of the test piece when the strain of the test piece is 300% is defined as Gc300, the storage modulus of the test piece can be expressed by the following formula:
X=Gc1/Gc300
The resin film has an X value calculated by the following formula: 19 or more and less than 10,000.

The resin film of the present invention may be applied to an uneven surface.
The resin film of the present invention may be curable.

The present invention also provides a composite sheet comprising a substrate, a buffer layer provided on the substrate, and a resin film provided on the buffer layer, wherein the resin film is the resin film of the present invention described above.
The present invention also provides a method for manufacturing a semiconductor device, comprising: an attachment step of attaching the curable resin film in the composite sheet of the present invention to a surface of a semiconductor wafer having bumps and causing the tops of the bumps to protrude from the resin film, thereby providing the composite sheet on the semiconductor wafer; a removal step of removing layers of the composite sheet other than the resin film from the resin film after the attachment step; a curing step of curing the resin film to form a first protective film after the removal step; a dividing step of dividing the semiconductor wafer to produce semiconductor chips after the curing step; a cutting step of cutting the first protective film after the curing step; and a mounting step of flip-chip connecting the semiconductor chip with the first protective film, the semiconductor chip having the tops of the bumps protruding from the first protective film, to a substrate at the tops of the bumps.

The present invention provides a resin film that can be applied to an uneven surface, which, when applied to the uneven surface, can penetrate the convex parts, can prevent the upper parts of the convex parts from remaining, and can prevent the resin film from protruding beyond its original size, and a composite sheet comprising the resin film that is used when applying the resin film to the uneven surface.

1 is a cross-sectional view schematically illustrating an example of a 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 resin film when the planar shape of the 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. FIG. 3 is a cross-sectional view schematically showing another example of a composite sheet according to an embodiment of the present invention. 4 is a cross-sectional view schematically showing an example of a method for manufacturing a semiconductor device when the composite sheet shown in FIG. 3 is used. 4 is a cross-sectional view schematically showing an example of a method for manufacturing a semiconductor device when the composite sheet shown in FIG. 3 is used. 4 is a cross-sectional view schematically showing an example of a method for manufacturing a semiconductor device when the composite sheet shown in FIG. 3 is used. 4 is a cross-sectional view schematically showing an example of a method for manufacturing a semiconductor device when the composite sheet shown in FIG. 3 is used. 5A to 5C are cross-sectional views schematically showing an example of a method for manufacturing a semiconductor device when the composite sheet shown in FIG. 4 is used. 5A to 5C are cross-sectional views schematically showing an example of a method for manufacturing a semiconductor device when the composite sheet shown in FIG. 4 is used. 5A to 5C are cross-sectional views schematically showing an example of a method for manufacturing a semiconductor device when the composite sheet shown in FIG. 4 is used. 5A to 5C are cross-sectional views schematically showing an example of a method for manufacturing a semiconductor device when the composite sheet shown in FIG. 4 is used. 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. FIG. 10 is a cross-sectional view schematically showing an example of a state in which a curable resin film remains on top of a bump.

Resin film and method for producing same In a resin film according to one embodiment of the present invention, a strain is generated in a test piece of the resin film having a diameter of 25 mm and a thickness of 1 mm under conditions of 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 when the strain of the test piece is 1% is defined as Gc1 and the storage modulus of the test piece when the strain of the test piece is 300% is defined as Gc300, the storage modulus of the test piece can be expressed by the following formula:
X=Gc1/Gc300
The X value calculated by the above formula is 19 or more and less than 10,000.

The test piece for measuring the strain dispersion is in the form of a film, and its planar shape is circular.
The test piece may be a single layer of the resin film having a thickness of 1 mm, but in terms of ease of preparation, it is preferable that the test piece be a laminated film composed of multiple single layer resin films having a thickness of less than 1 mm.
The thicknesses of the multiple single-layer 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 standpoint of ease of production, it is preferable that they all be the same.

In this specification, "storage modulus of a test specimen" refers not only to Gc1 and Gc300 but also to "the storage modulus of a test specimen corresponding to the strain generated when a strain is generated in a resin film test specimen having a diameter of 25 mm and a thickness of 1 mm under conditions of a temperature of 90°C and a frequency of 1 Hz."

The resin film of this embodiment can be laminated with a substrate and a buffer layer, for example, as described below, to form a composite sheet.

FIG. 1 is a cross-sectional view schematically illustrating an example of a 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 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 resin film 12 is suitable for storage, for example, in a roll form.

The X value of the test piece of 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 peeled from the resin film 12 .

When either the first release film 151 or the second release film 152 is removed from the 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) 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 resin film 12, but the release film may be provided on only one side of the resin film 12, i.e., only the first side 12a or only the second side 12b.

The resin film of the present embodiment may be curable or non-curable. For example, the resin film may function as a protective film (e.g., a first protective film described later; the same applies hereinafter) when cured, or may function as a protective film in an uncured state.
The curable resin film may be either thermosetting or energy ray curable, or may have both thermosetting and energy ray curable properties.

When forming a protective film using the resin film of this embodiment, it is preferable that the resin film be curable, as this allows for the formation of a protective film with higher protective properties.

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 addition, 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.
Furthermore, "non-curable" means a property that does not cure by any means such as heating, irradiation with energy rays, etc. A non-curable film for forming a protective film is considered to be a protective film after it is provided (formed) on a target object.

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

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

The resin film of this embodiment is soft and suitable for application to uneven surfaces.
When the resin film of this embodiment is applied to an uneven surface while being heated, the convex portions of the uneven surface penetrate the resin film, causing the upper portions of the convex portions to protrude from the resin film. The softened resin film then spreads between the convex portions, covering them, and adheres closely to the uneven surface. It also covers the surfaces of the convex portions, particularly the surfaces near the uneven surface, burying the bases of the convex portions. In this state, the resin film is prevented from remaining above the convex portions. If the resin film is curable, the cured resin film in this state is also naturally prevented from adhering to the upper portions of the convex portions. Furthermore, after application, the resin film is prevented from protruding from its original size, thereby preventing, for example, the resin film from protruding from the uneven surface. The reason for this prevention of the resin film remaining and protruding is that the resin film satisfies the X value condition (19≦X value<10,000).
Furthermore, when the resin film is used, when the resin film and its cured product are provided on the uneven surface, regions of the convex portions of the uneven surface other than the upper portions (for example, base portions near the uneven surface) or regions near the convex portions of the uneven surface are unintentionally exposed without being covered with the resin film and its cured product, i.e., so-called repelling is suppressed. The reason why the basic properties of the resin film are thus good is also because the resin film satisfies the condition of the X value (19≦X value<10000).
As described above, the resin film of this embodiment has extremely excellent properties in that the entire uneven surface can be covered with the resin film itself and its cured product while leaving the convex portions exposed.

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

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

When applying the resin film of this embodiment to an uneven surface, the composite sheet provided with the resin film of this embodiment can be used. The composite sheet will be described in more detail later.

More specifically, an example of an object to which the resin film is to be attached, which has an uneven surface, is a semiconductor wafer having bumps.
That is, the resin film can be attached to a semiconductor wafer before it is divided into semiconductor chips. In this case, the 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."

When the resin film is applied to the bump-forming surface while being heated, the bumps penetrate the resin film, causing the tops of the bumps to protrude from the resin film. The softened resin film then spreads between the bumps, covering them and adhering 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 state, the resin film is prevented from remaining in the tops and other upper portions of the bumps. If the resin film is curable, the cured resin film is also naturally prevented from adhering to the tops of the bumps. Furthermore, after application, the resin film is prevented from protruding from its original size, thereby preventing, for example, the resin film from protruding from the bump-forming surface of the semiconductor wafer. Furthermore, when the resin film and its cured resin are applied to the bump-forming surface, unintentional exposure (i.e., repelling) of areas other than the tops of the bumps or areas of the bump-forming surface near the bumps is prevented. The reasons why these effects are obtained are as described above.

If the resin film is curable, the resin film in this state (with the base of the bump embedded) will then harden to ultimately form the first protective film; if the resin film is non-curable, the resin film from this state (with the base of the bump embedded) onwards will become 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."

If a resin film protrudes from its original size when it is applied to an object, such as when it is applied to an uneven surface, the resin film in this protruding state can be viewed in a planar view from above, and the maximum length of the line segment connecting two different points on the circumference of the resin film at this time can be found.Furthermore, the original width of the resin film (i.e., before it protruded) at the position where it overlaps with the line segment indicating this maximum length can be found, and the width of the resin film can be calculated by subtracting the value of the width of the 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 resin film when the planar shape of the 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 resin film 101 shown here protrudes from its original size when attached to the object 102. The resin film has its original size indicated by the reference symbol 101', which is shown for convenience to make it easier to understand the amount of protrusion. The original planar shape of the resin film 101' is circular here, but the planar shape of the protruding resin film 101 is non-circular. However, this is just one example, and the planar shape of the protruding resin film 101 is not limited to that shown here.

To find the amount of protrusion of resin film 101, the maximum value of length D1 of the line segment connecting point 1010a on outer periphery 1010 of resin film 101 and another point 1010b is found, and then the value _D0 of the initial width of resin film 101' (i.e., before protrusion) at the position where it overlaps with the line segment showing this maximum value is found. The difference between _D1 and _D0 ( _D1 - _{D0 )} is the amount of protrusion.
The line segment indicating the maximum value in resin film 101 may pass through the center of the circle in original resin film 101' when viewed in a plane, in which case the width value of original resin film 101' at the position where it overlaps with the line segment indicating this maximum value becomes the diameter of resin film 101'.

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

When a resin film is applied to the uneven surface of an object to be applied, the degree of distortion of the 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 to be applied is a semiconductor wafer with bumps) penetrate the resin film and protrude, and the final stage when the resin film embeds the bases of the convex portions after the tops of the convex portions have penetrated the resin film and protrude. More specifically, the distortion of the resin film is large in the middle stage and small in the final stage.
The 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 by making Gc1 high and Gc300 low, the excellent effects described above are achieved.

In the resin film, the X value may be 19 or more and less than 10,000. For example, the X value may be any of 5,000 or less, 2,000 or less, 1,000 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, 19 to 2000, 19 to 1000, 19 to 500, 19 to 300, 19 to 100, and 19 to 70.

Unlike the resin film of this embodiment, other resin films with an X value of 10,000 or more do not exhibit the effect of suppressing repelling, even when the tops of the convex portions protrude from the other resin film when applied to an uneven surface, and the cured product of the other resin film also remains in a state where repelling occurs.

In the resin film, Gc1 is not particularly limited as long as the X value is 19 or more and less than 10,000.
However, as explained above, it is preferable that Gc1 is 1 x 10 4 to 1 x 10 6 Pa in order to achieve a high level of the effects of suppressing the resin film ^from remaining on the top of the convex portions, the effects of suppressing the resin film from protruding, and the effects of suppressing the ^resin film and its cured product from cissing.

In the 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 reason as in the case of Gc1 above, Gc300 is preferably 1 to 5000 Pa.

It is preferable that the resin film satisfies both of the above conditions, that is, Gc1 is 1×10 ⁴ to 1×10 ⁶ Pa and Gc300 is 1 to 5000 Pa.

The storage modulus of the resin film can be easily adjusted by adjusting the type or content of the components contained in the 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 resin film can be adjusted. For example, when using the thermosetting resin film-forming composition (III) described below, the storage modulus of the 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.

Regardless of whether the resin film is curable or non-curable, and if it is curable, regardless of whether it is heat-curable or energy ray-curable, the resin film may consist of one layer (single layer) or two or more layers. When the resin film consists of multiple layers, these multiple layers may be the same or different, and the combination of these multiple layers is not particularly limited.

In this specification, not only in the case of the 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."

Regardless of whether the resin film is curable or non-curable, and if it is curable, regardless of whether it is thermosetting or energy ray-curable, the thickness of the resin film is preferably 1 to 100 μm, more preferably 5 to 75 μm, and particularly preferably 5 to 50 μm. When the thickness of the resin film is equal to or greater than the lower limit, the effect of the resin film is enhanced. For example, when a protective film is formed using a resin film, a protective film with higher protective ability can be formed. On the other hand, when the thickness of the resin film is equal to or less than the upper limit, excessive thickness is prevented.
Here, "thickness of the resin film" means the thickness of the entire resin film, and for example, the thickness of a resin film consisting of multiple layers means the total thickness of all layers that make up the resin film.

<<Resin film-forming composition>>
The resin film can be formed using a resin film-forming composition containing its constituent materials. For example, the resin film can be formed by applying the resin film-forming composition 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 resin film-forming composition is usually the same as the ratio of the contents of the components in the resin film. In this specification, "room temperature" means a temperature that is not particularly cooled or heated, i.e., an ordinary temperature, and examples thereof include a temperature of 15 to 25°C.

A thermosetting resin film can be formed using a thermosetting resin film-forming composition, an energy ray-curable resin film can be formed using an energy ray-curable resin film-forming composition, and a non-curable resin film can be formed using a non-curable resin film-forming composition. In this specification, when a resin film has both thermosetting and energy ray-curable properties, and the contribution of the thermosetting of the resin film to its curing (e.g., formation of a protective film) is greater than the contribution of the energy ray-curing, the resin film is treated as thermosetting. Conversely, when the contribution of the energy ray-curing of the resin film to its curing is greater than the contribution of the thermosetting, the resin film is treated as energy ray-curable.

In the resin film, the ratio of the total content of one or more components contained in the resin film, which will be described later, to the total mass of the resin film does not exceed 100% by mass.
Similarly, in the resin film-forming composition, the ratio of the total content of one or more components described below contained in the resin film-forming composition to the total mass of the resin film-forming composition does not exceed 100 mass %.

The resin film-forming composition may be applied by any known method, 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, or kiss coater.

Regardless of whether the resin film is curable or non-curable, and if it is curable, regardless of whether it is heat-curable or energy ray-curable, the drying conditions for the resin film-forming composition are not particularly limited. However, if the resin film-forming composition contains a solvent, as described below, it is preferable to heat-dry it. Furthermore, a 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 neither the composition itself nor the thermosetting resin film formed from this composition is thermally cured.

Thermosetting resin films and energy ray-curable resin films are described in further 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, in the case of 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 the thermal curing is preferably 0.5 to 5 hours, more preferably 0.5 to 4 hours, and particularly preferably 1 to 3 hours.

<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), a filler (D), and an additive (I).

[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. When the weight-average molecular weight of the polyvinyl acetal is within this range, the following effects are enhanced: when a thermosetting resin film is applied to the uneven surface, the effect of suppressing the thermosetting resin film from remaining on the tops of the convex portions of the uneven surface (for example, when a thermosetting resin film is applied to the bump-forming surface, the effect of suppressing the thermosetting resin film from remaining on the tops of the bumps; the same applies hereinafter); when a thermosetting resin film is applied to the bump-forming surface, the effect of suppressing the thermosetting resin film from protruding from its original size on the uneven surface (for example, when a thermosetting resin film is applied to the bump-forming surface, the effect of suppressing the thermosetting resin film from protruding from its original size on the bump-forming surface; the same applies hereinafter); and when a thermosetting resin film and its cured product are suppressed from repelling on the uneven surface (for example, when a thermosetting resin film is applied to the bump-forming surface, the effect of suppressing the thermosetting resin film and its cured product from repelling on the bump-forming surface; the same applies hereinafter).

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 enhances the effects of preventing the thermosetting resin film from remaining on the tops of the convex portions of the uneven surface when the thermosetting resin film is applied to the uneven surface, preventing the thermosetting resin film from protruding from the uneven surface, and preventing the thermosetting resin film and its cured product from repelling 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 in this range, when the thermosetting resin film is attached to the uneven surface, the effects of suppressing the thermosetting resin film from remaining on the tops of the convex portions of the uneven surface, suppressing the thermosetting resin film from protruding 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 enhances the effects of preventing the thermosetting resin film from remaining on the tops of the convex portions of the uneven surface when the thermosetting resin film is applied to the uneven surface, preventing the thermosetting resin film from spilling over the uneven surface, and preventing the thermosetting resin film and its cured product from repelling 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 25% by mass, and more preferably 5 to 15% by mass, regardless of the type of polymer component (A).

[Thermosetting component (B)]
The thermosetting component (B) has thermosetting properties and is a component for thermally curing 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 200 to 800 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 the composition (III) and the thermosetting resin film, the content of the thermosetting component (B) (e.g., the total content of the epoxy resin (B1) and the thermosetting agent (B2)) is preferably 600 to 1,000 parts by mass per 100 parts by mass of the content of the polymer component (A). When the content of the thermosetting component (B) is in this range, when the thermosetting resin film is attached to the uneven surface, the effects of suppressing the thermosetting resin film from remaining on the tops of the convex portions of the uneven surface, suppressing the thermosetting resin film from protruding from the uneven surface, and suppressing cissing of the thermosetting resin film and its cured product on the uneven surface are enhanced, and a hard cured product (e.g., a 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).

For example, when polymer component (A) is the polyvinyl acetal, the content of thermosetting component (B) in composition (III) and the thermosetting resin film is preferably 600 to 1,000 parts by mass, more preferably 650 to 1,000 parts by mass, and particularly preferably 650 to 950 parts by mass, per 100 parts by mass of polymer component (A).

[Filler (D)]
By adjusting the amount of filler (D) in the composition (III) and the thermosetting resin film, the X value can be more easily adjusted. Furthermore, by adjusting the amount of filler (D) in the composition (III) and the thermosetting resin film, the thermal 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 thermal 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) in the thermosetting resin film to the total mass of the thermosetting resin film) is preferably 5 to 45% by mass, more preferably 5 to 40% by mass, and even more preferably 5 to 30% by mass. Having this ratio within this range enhances the effects of suppressing the thermosetting resin film from remaining on the tops of the convex portions of the uneven surface when the thermosetting resin film is applied to the uneven surface, suppressing the thermosetting resin film from protruding from the uneven surface, and suppressing cissing of the thermosetting resin film and its cured product on the uneven surface, while also making it easier to adjust the thermal expansion coefficient.

[Additive (I)]
The X value can be more easily adjusted by adjusting the type or amount of the additive (I) in the composition (III) and the thermosetting resin film.
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).
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 20 parts by mass, more preferably 0.05 to 10 parts by mass, and particularly preferably 0.1 to 5 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.

Energy Ray-Curable Resin Film When the energy ray-curable 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, and may be appropriately selected depending on the type of energy ray-curable resin film, the application of the cured product, etc.
For example, when forming a protective film, the illuminance of the energy rays during curing of the energy ray-curable resin film is preferably 180 to 280 mW/ ^cm2 . The light amount of the energy rays during curing is preferably 450 to 1000 mJ/ ^cm2 .

<Energy ray-curable resin film-forming composition>
[0043] Examples of the composition for forming an energy ray-curable resin film include a composition for forming an energy ray-curable resin film (IV) (sometimes simply referred to as "composition (IV)" in this specification) containing an energy ray-curable component (a), a filler, and an additive.

[Energy ray-curable component (a)]
The energy ray-curable component (a) is a component that is cured by irradiation with energy rays, and is also a component that imparts film-forming properties, flexibility, etc. to the energy ray-curable resin film.
The energy ray-curable component (a) is preferably uncured and has adhesive properties, and more preferably uncured and has adhesive properties.

Examples of the energy ray-curable component (a) include a polymer (a1) having an energy ray-curable group and a weight-average molecular weight of 80,000 to 2,000,000, and a compound (a2) having an energy ray-curable group and a molecular weight of 100 to 80,000. The polymer (a1) may be at least partially crosslinked with a crosslinking agent, or may not be crosslinked.

(Polymer (a1) having an energy ray-curable group and a weight-average molecular weight of 80,000 to 2,000,000)
Examples of the polymer (a1) having an energy ray-curable group and a weight average molecular weight of 80,000 to 2,000,000 include an acrylic resin (a1-1) obtained by polymerizing an acrylic polymer (a11) having a functional group capable of reacting with a group possessed by another compound and an energy ray-curable compound (a12) having a group reactive with the functional group and an energy ray-curable group such as an energy ray-curable double bond.

Examples of the functional group capable of reacting with a group possessed by another compound include a hydroxyl group, a carboxy group, an amino group, a substituted amino group (a group in which one or two hydrogen atoms of an amino group are substituted with a group other than a hydrogen atom), an epoxy group, etc. However, from the viewpoint of preventing corrosion of circuits of a semiconductor wafer, a semiconductor chip, etc., it is preferable that the functional group be a group other than a carboxy group.
Among these, the functional group is preferably a hydroxyl group.

Acrylic polymer (a11) having a functional group
The acrylic polymer (a11) having a functional group may be, for example, a polymer obtained by copolymerizing an acrylic monomer having the functional group with an acrylic monomer not having the functional group. In addition to these monomers, the acrylic polymer may also be a polymer obtained by copolymerizing a monomer other than the acrylic monomer (a non-acrylic monomer).
The acrylic polymer (a11) may be a random copolymer or a block copolymer.

Examples of acrylic monomers having the functional group include hydroxyl group-containing monomers, carboxyl group-containing monomers, amino group-containing monomers, substituted amino group-containing monomers, and epoxy group-containing monomers.

Examples of the hydroxyl group-containing monomer include hydroxyalkyl (meth)acrylates 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; non-(meth)acrylic unsaturated alcohols (unsaturated alcohols without a (meth)acryloyl skeleton) such as vinyl alcohol and allyl alcohol; and the like.

Examples of the carboxy group-containing monomer include ethylenically unsaturated monocarboxylic acids (monocarboxylic acids having an ethylenically unsaturated bond) such as (meth)acrylic acid and crotonic acid; ethylenically unsaturated dicarboxylic acids (dicarboxylic acids having an ethylenically unsaturated bond) such as fumaric acid, itaconic acid, maleic acid, and citraconic acid; anhydrides of the above ethylenically unsaturated dicarboxylic acids; and (meth)acrylic acid carboxyalkyl esters such as 2-carboxyethyl methacrylate.

The acrylic monomer having the functional group is preferably a hydroxyl group-containing monomer or a carboxyl group-containing monomer, and more preferably a hydroxyl group-containing monomer.

The acrylic monomer having the functional group that constitutes the acrylic polymer (a11) may be of only one type 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 monomers not having the functional group 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, and isopropyl (meth)acrylate. Examples thereof include alkyl (meth)acrylates in which the alkyl group constituting the alkyl ester has a chain structure and has 1 to 18 carbon atoms, such as sononyl, 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).

Examples of acrylic monomers that do not have the functional group include (meth)acrylic acid esters containing an alkoxyalkyl group, such as methoxymethyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxymethyl (meth)acrylate, and ethoxyethyl (meth)acrylate; (meth)acrylic acid esters with an aromatic group, including aryl (meth)acrylate esters such as phenyl (meth)acrylate; non-crosslinkable (meth)acrylamide and its derivatives; and (meth)acrylic acid esters with a non-crosslinkable tertiary amino group, such as N,N-dimethylaminoethyl (meth)acrylate and N,N-dimethylaminopropyl (meth)acrylate.

The acrylic monomer not having a functional group constituting the acrylic polymer (a11) may be of only one type 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 the non-acrylic monomer include olefins such as ethylene and norbornene; vinyl acetate; and styrene.
The non-acrylic monomer constituting the acrylic polymer (a11) may be one kind or two or more kinds, and when two or more kinds are used, the combination and ratio thereof can be selected arbitrarily.

In the acrylic polymer (a11), the proportion (content) of the structural units derived from the acrylic monomer having the functional group relative to the total amount of structural units constituting the acrylic polymer (a11) is preferably 0.1 to 50% by mass, more preferably 1 to 40% by mass, and particularly preferably 3 to 30% by mass. When the proportion is within this range, the content of energy ray-curable groups in the acrylic resin (a1-1) obtained by copolymerization of the acrylic polymer (a11) and the energy ray-curable compound (a12) makes it possible to easily adjust the degree of curing of the cured product (e.g., protective film) of the energy ray-curable resin film within a preferred range.

The acrylic polymer (a11) constituting the acrylic resin (a1-1) may be of only one type or of two or more types, and if there are two or more types, the combination and ratio thereof can be selected arbitrarily.

In composition (IV), the ratio of the content of acrylic resin (a1-1) to the total content of components other than the solvent (i.e., the ratio of the content of acrylic resin (a1-1) to the total mass of the energy ray-curable resin film) is preferably 1 to 40% by mass, more preferably 2 to 30% by mass, and particularly preferably 3 to 20% by mass.

Energy ray-curable compound (a12)
The energy ray-curable compound (a12) preferably has one or more groups selected from the group consisting of an isocyanate group, an epoxy group, and a carboxy group as a group reactive with the functional group of the acrylic polymer (a11), and more preferably has an isocyanate group as the group. For example, when the energy ray-curable compound (a12) has an isocyanate group as the group, the isocyanate group easily reacts with the hydroxyl group of the acrylic polymer (a11) having a hydroxyl group as the functional group.

The energy ray-curable compound (a12) preferably has 1 to 5 of the energy ray-curable groups in one molecule, and more preferably has 1 to 2 of the energy ray-curable groups in one molecule.

Examples of the energy ray-curable compound (a12) include 2-methacryloyloxyethyl isocyanate, meta-isopropenyl-α,α-dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, and 1,1-(bisacryloyloxymethyl)ethyl isocyanate;
an acryloyl monoisocyanate compound obtained by reacting a diisocyanate compound or a polyisocyanate compound with hydroxyethyl (meth)acrylate;
Examples of the isocyanate include an acryloyl monoisocyanate compound obtained by reacting a diisocyanate compound or a polyisocyanate compound with a polyol compound and hydroxyethyl (meth)acrylate.
Among these, the energy ray-curable compound (a12) is preferably 2-methacryloyloxyethyl isocyanate.

The energy ray-curable compound (a12) constituting the acrylic resin (a1-1) may be of only one type or of two or more types, and if there are two or more types, the combination and ratio thereof can be selected arbitrarily.

In the acrylic resin (a1-1), the ratio of the content of the energy ray-curable groups derived from the energy ray-curable compound (a12) to the content of the functional groups derived from the acrylic polymer (a11) is preferably 20 to 120 mol%, more preferably 35 to 100 mol%, and particularly preferably 50 to 100 mol%. This range of content ratio increases the adhesive strength of the cured product (e.g., protective film) of the energy ray-curable resin film. Note that when the energy ray-curable compound (a12) is a monofunctional compound (having one such group per molecule), the upper limit of this content ratio is 100 mol%. However, when the energy ray-curable compound (a12) is a polyfunctional compound (having two or more such groups per molecule), the upper limit of this content ratio may exceed 100 mol%.

The weight average molecular weight (Mw) of the polymer (a1) is preferably 100,000 to 2,000,000, and more preferably 300,000 to 1,500,000.

When the polymer (a1) is at least partially crosslinked with a crosslinking agent, the polymer (a1) may be formed by polymerizing a monomer that does not fall under any of the above-mentioned monomers described as constituting the acrylic polymer (a11) and has a group reactive with the crosslinking agent, and crosslinking the group reactive with the crosslinking agent; or the polymer (a1) may be formed by crosslinking a group reactive with the functional group derived from the energy ray-curable compound (a12).

The polymer (a1) contained in composition (IV) and the energy ray-curable resin film may be one type or two or more types, and if two or more types are contained, the combination and ratio thereof can be selected arbitrarily.

(Compound (a2) having an energy ray-curable group and a molecular weight of 100 to 80,000)
[0047] Examples of the energy ray-curable group in the compound (a2) having an energy ray-curable group and having a molecular weight of 100 to 80,000 include groups containing an energy ray-curable double bond, and preferred examples thereof include a (meth)acryloyl group and a vinyl group.

The compound (a2) is not particularly limited as long as it satisfies the above conditions, but examples include low-molecular-weight compounds having energy ray-curable groups, epoxy resins having energy ray-curable groups, and phenolic resins having energy ray-curable groups.

Among the compounds (a2), examples of the low molecular weight compound having an energy ray-curable group include polyfunctional monomers or oligomers, and acrylate compounds having a (meth)acryloyl group are preferred.
Examples of the acrylate compounds include 2-hydroxy-3-(meth)acryloyloxypropyl methacrylate, polyethylene glycol di(meth)acrylate, propoxylated ethoxylated bisphenol A di(meth)acrylate, 2,2-bis[4-((meth)acryloxypolyethoxy)phenyl]propane, ethoxylated bisphenol A di(meth)acrylate, 2,2-bis[4-((meth)acryloxydiethoxy)phenyl]propane, 9,9-bis[4-(2-(meth)acryloyloxyethoxy)phenyl]fluorene, 2,2-bis[4-((meth)acryloxypolypropoxy)phenyl]propane, tricyclodecane dimethanol di(meth)acrylate, 1,10-decanediol ... bifunctional (meth)acrylates such as 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, 2,2-bis[4-((meth)acryloxyethoxy)phenyl]propane, neopentyl glycol di(meth)acrylate, ethoxylated polypropylene glycol di(meth)acrylate, and 2-hydroxy-1,3-di(meth)acryloxypropane;
polyfunctional (meth)acrylates such as tris(2-(meth)acryloxyethyl)isocyanurate, ε-caprolactone-modified tris-(2-(meth)acryloxyethyl)isocyanurate, ethoxylated glycerin tri(meth)acrylate, pentaerythritol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol poly(meth)acrylate, and dipentaerythritol hexa(meth)acrylate;
Examples include polyfunctional (meth)acrylate oligomers such as urethane (meth)acrylate oligomers.

Of the compounds (a2), examples of epoxy resins having energy ray-curable groups and phenolic resins having energy ray-curable groups that can be used include those described in paragraph 0043 of JP 2013-194102 A. Although such resins also fall under the category of resins that constitute the thermosetting component described below, they are treated as compound (a2) in the present invention.

The weight average molecular weight of the compound (a2) is preferably 100 to 30,000, and more preferably 300 to 10,000.

The compound (a2) contained in composition (IV) and the energy ray-curable 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.

[Polymer (b) having no energy ray-curable group]
When the composition (IV) and the energy ray-curable resin film contain the compound (a2) as the energy ray-curable component (a), they preferably further contain a polymer (b) having no energy ray-curable group.
The polymer (b) may be at least partially crosslinked with a crosslinking agent, or may not be crosslinked.

Examples of the polymer (b) having no energy ray-curable group include acrylic polymers, phenoxy resins, urethane resins, polyesters, rubber-based resins, and acrylic urethane resins.
Among these, the polymer (b) is preferably an acrylic polymer (hereinafter sometimes abbreviated as "acrylic polymer (b-1)").

The acrylic polymer (b-1) may be a known polymer, for example, a homopolymer of one type of acrylic monomer, a copolymer of two or more types of acrylic monomers, or a copolymer of one or more types of acrylic monomers and one or more types of monomers other than acrylic monomers (non-acrylic monomers).

Examples of the acrylic monomer that constitutes the acrylic polymer (b-1) include (meth)acrylic acid alkyl esters, (meth)acrylic acid esters with a cyclic skeleton, glycidyl group-containing (meth)acrylic acid esters, hydroxyl group-containing (meth)acrylic acid esters, and substituted amino group-containing (meth)acrylic acid esters. Here, the term "substituted amino group" is as described above.

Examples of the (meth)acrylic acid alkyl ester include the same as the acrylic monomer not having the functional group that constitutes the acrylic polymer (a11) described above (e.g., a (meth)acrylic acid alkyl ester in which the alkyl group constituting the alkyl ester has a chain structure containing 1 to 18 carbon atoms).

Examples of the (meth)acrylic acid ester having a cyclic skeleton include (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 are included.

Examples of the glycidyl group-containing (meth)acrylic acid ester include glycidyl (meth)acrylate.
Examples of the hydroxyl group-containing (meth)acrylic acid ester include 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 of the substituted amino group-containing (meth)acrylic acid ester include N-methylaminoethyl (meth)acrylate.

Examples of the non-acrylic monomers that constitute the acrylic polymer (b-1) include olefins such as ethylene and norbornene; vinyl acetate; styrene; etc.

The polymer (b) having no energy ray-curable group and at least a portion of which is crosslinked with a crosslinking agent may be, for example, a polymer in which a reactive functional group in the polymer (b) has reacted with a crosslinking agent.
The reactive functional group may be appropriately selected depending on the type of crosslinking agent, and is not particularly limited. For example, when the crosslinking agent is a polyisocyanate compound, examples of the reactive functional group include a hydroxyl group, a carboxyl group, an amino group, etc., and among these, a hydroxyl group, which has high reactivity with an isocyanate group, is preferred. When the crosslinking agent is an epoxy compound, examples of the reactive functional group include a carboxyl group, an amino group, an amide group, etc., and among these, a carboxyl group, which has high reactivity with an epoxy group, is preferred. However, from the viewpoint of preventing corrosion of the circuits of a semiconductor wafer or a semiconductor chip, it is preferable that the reactive functional group be a group other than a carboxyl group.

Examples of the polymer (b) having the reactive functional group but not the energy ray-curable group include those obtained by polymerizing at least a monomer having the reactive functional group. In the case of acrylic polymer (b-1), it is sufficient to use one or both of the acrylic monomers and non-acrylic monomers listed as the constituent monomers that have the reactive functional group. Examples of the polymer (b) having a hydroxyl group as a reactive functional group include those obtained by polymerizing a hydroxyl group-containing (meth)acrylic acid ester, and also those obtained by polymerizing a monomer in which one or more hydrogen atoms in the acrylic monomers or non-acrylic monomers listed above have been substituted with the reactive functional group.

In the polymer (b) having a reactive functional group, the proportion (content) of the structural units derived from the monomer having a reactive functional group relative to the total amount of structural units constituting the polymer (b) is preferably 1 to 20% by mass, and more preferably 2 to 10% by mass. Having this proportion within this range results in a more preferable range for the degree of crosslinking in the polymer (b).

The weight average molecular weight (Mw) of polymer (b) that does not have an energy ray-curable group is preferably 10,000 to 2,000,000, and more preferably 100,000 to 1,500,000, in order to improve the film-forming properties of composition (IV).

The polymer (b) not having an energy ray-curable group contained in composition (IV) and the energy ray-curable 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.

Examples of composition (IV) include compositions containing either or both of the polymer (a1) and the compound (a2). When composition (IV) contains compound (a2), it preferably also contains polymer (b) that does not have an energy ray-curable group, and in this case, it is also preferable that composition (IV) further contains (a1). Alternatively, composition (IV) may contain both polymer (a1) and polymer (b) that does not have an energy ray-curable group without containing compound (a2).

When composition (IV) contains the polymer (a1), the compound (a2), and the polymer (b) that does not have an energy ray-curable group, the content of the compound (a2) in composition (IV) is preferably 10 to 400 parts by mass, and more preferably 30 to 350 parts by mass, per 100 parts by mass of the total content of the polymer (a1) and the polymer (b) that does not have an energy ray-curable group.

In composition (IV), the ratio of the total content of the energy ray-curable component (a) and the polymer (b) not having an energy ray-curable group to the total content of components other than the solvent (i.e., in the energy ray-curable resin film, the ratio of the total content of the energy ray-curable component (a) and the polymer (b) not having an energy ray-curable group to the total mass of the film) is preferably 5 to 90% by mass, more preferably 10 to 80% by mass, and particularly preferably 20 to 70% by mass. Having this ratio within this range improves the energy ray curability of the energy ray-curable resin film.

[Filling material]
The X value can be more easily adjusted by adjusting the amount of filler in the composition (IV) and the energy ray-curable resin film. Furthermore, by adjusting the amount of filler in the composition (IV) and the energy ray-curable resin film, the thermal expansion coefficient of the cured product of the energy ray-curable resin film (e.g., a protective film) can be more easily adjusted. For example, by optimizing the thermal 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 energy ray-curable resin film can be further improved. Furthermore, by using an energy ray-curable resin film containing a filler, the moisture absorption rate of the cured product of the energy ray-curable resin film (e.g., a protective film) can be reduced and the heat dissipation properties can be improved.

The filler contained in composition (IV) and the energy ray-curable resin film is the same as the filler (D) contained in composition (III) and the thermosetting resin film described above.

The manner in which the filler is contained in composition (IV) and the energy ray-curable resin film may be the same as the manner in which the filler (D) is contained in composition (III) and the thermosetting resin film.

The filler contained in composition (IV) and the energy ray-curable resin film may be one type or two or more types, and if two or more types are contained, the combination and ratio thereof can be selected arbitrarily.

In composition (IV), the ratio of the filler content to the total content of all components other than the solvent (i.e., the ratio of the filler content to the total mass of the energy ray-curable resin film in the energy ray-curable resin film) may be, for example, 5 to 45 mass%. By having this ratio within this range, when the energy ray-curable resin film is applied to the uneven surface, the effects of suppressing the energy ray-curable resin film from remaining on the tops of the convex portions of the uneven surface, suppressing protrusion of the energy ray-curable resin film from the uneven surface, and suppressing repelling of the energy ray-curable resin film and its cured product on the uneven surface are further enhanced, and the thermal expansion coefficient can be more easily adjusted.

[Additives]
The X value can be more easily adjusted by adjusting the type or amount of additives in the composition (IV) and the energy ray-curable resin film.

The additives contained in the composition (IV) and the energy ray-curable resin film are the same as the additives (I) contained in the composition (III) and the thermosetting resin film described above.
For example, preferred additives that allow for easier adjustment of the X value include rheology control agents, surfactants, silicone oils, and the like.

The manner in which the additives in composition (IV) and the energy ray-curable resin film are contained may be the same as the manner in which the additives in composition (III) and the thermosetting resin film are contained (I).

The additives contained in composition (IV) and the energy ray-curable 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 additives in the composition (IV) and the energy ray-curable 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 the additive to the total content of all components other than the solvent in composition (IV) (i.e., the ratio of the content of the additive to the total mass of the energy ray-curable resin film in the energy ray-curable resin film) may be, for example, 0.5 to 10 mass%.

[Other ingredients]
The composition (IV) and the energy ray-curable resin film may contain other components that do not fall under any of the energy ray-curable component (a), the filler, the additive, and the polymer (b) having no energy ray-curable group, within a range that does not impair the effects of the present invention.
Examples of the other components include a thermosetting component, a photopolymerization initiator, a coupling agent, a crosslinking agent, etc. For example, by using the composition (IV) containing the energy ray-curable component (a) and the thermosetting component, the adhesive strength of the energy ray-curable resin film to an adherend is improved by heating, and the strength of the cured product of the energy ray-curable resin film (e.g., a protective film) is also improved.

The thermosetting component, photopolymerization initiator, coupling agent, and crosslinking agent in composition (IV) may be the same as the thermosetting component (B), photopolymerization initiator, coupling agent (E), and crosslinking agent (F) in composition (III), respectively.

The other components contained in the composition (IV) and the energy ray-curable resin film may be one type only or two or more types. When two or more types are contained, the combination and ratio thereof can be selected arbitrarily.
The contents of the composition (IV) and the other components in the energy ray-curable resin film are not particularly limited and may be appropriately selected depending on the purpose.

[solvent]
Composition (IV) preferably further contains a solvent, since composition (IV) containing a solvent has good handleability.
Examples of the solvent contained in the composition (IV) include the same solvents as those contained in the composition (III) described above.
The composition (IV) 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.
The content of the solvent in the composition (IV) is not particularly limited and may be appropriately selected depending on, for example, the types of components other than the solvent.

<Method for producing energy ray-curable resin film-forming composition>
The energy ray-curable resin film-forming composition such as composition (IV) can be obtained by blending the components constituting the composition.
The energy ray-curable resin film-forming composition can be produced by the same method as the thermosetting resin film-forming composition described above, except that the types of ingredients used are different.

An example of a preferable resin film of the present embodiment is a resin film,
A strain was generated in a test piece of the resin film having a diameter of 25 mm and a thickness of 1 mm under conditions of a temperature of 90°C and a frequency of 1 Hz, and the storage modulus of the test piece was measured. When the storage modulus of the test piece when the strain of the test piece is 1% is defined as Gc1, and the storage modulus of the test piece when the strain of the test piece is 300% is defined as Gc300, the following formula was obtained:
X=Gc1/Gc300
The X value calculated by is 19 or more and less than 10,000,
the resin film is a thermosetting resin film containing a polymer component (A), an epoxy resin (B1), a thermosetting agent (B2), a filler (D), and an additive (I),
the content of the polymer component (A) in the resin film is 5 to 25% by mass relative to the total mass of the resin film;
the content of the thermosetting agent (B2) in the resin film is 0.1 to 500 parts by mass per 100 parts by mass of the epoxy resin (B1);
a total content of the epoxy resin (B1) and the thermosetting agent (B2) in the resin film is 600 to 1000 parts by mass per 100 parts by mass of the polymer component (A);
The content ratio of the filler (D) in the resin film relative to the total mass of the resin film is 5 to 45 mass%,
The content ratio of the additive (I) in the resin film relative to the total mass of the resin film is 0.5 to 10 mass%,
However, in the resin film, the ratio of the total content of the polymer component (A), the epoxy resin (B1), the thermosetting agent (B2), the filler (D), and the additive (I) to the total mass of the resin film does not exceed 100 mass%.

Another example of a preferable resin film of the present embodiment is a resin film,
A strain was generated in a test piece of the resin film having a diameter of 25 mm and a thickness of 1 mm under conditions of a temperature of 90°C and a frequency of 1 Hz, and the storage modulus of the test piece was measured. When the storage modulus of the test piece when the strain of the test piece is 1% is defined as Gc1, and the storage modulus of the test piece when the strain of the test piece is 300% is defined as Gc300, the following formula was obtained:
X=Gc1/Gc300
The X value calculated by is 19 or more and less than 10,000,
the resin film is a thermosetting resin film containing a polymer component (A), an epoxy resin (B1), a thermosetting agent (B2), a filler (D), and an additive (I),
the polymer component (A) is polyvinyl acetal,
the additive (I) is one or more selected from the group consisting of a rheology control agent, a surfactant, and a silicone oil,
the content of the polymer component (A) in the resin film is 5 to 25% by mass relative to the total mass of the resin film;
the content of the thermosetting agent (B2) in the resin film is 0.1 to 500 parts by mass per 100 parts by mass of the epoxy resin (B1);
a total content of the epoxy resin (B1) and the thermosetting agent (B2) in the resin film is 600 to 1000 parts by mass per 100 parts by mass of the polymer component (A);
The content ratio of the filler (D) in the resin film relative to the total mass of the resin film is 5 to 45 mass%,
The content ratio of the additive (I) in the resin film relative to the total mass of the resin film is 0.5 to 10 mass%,
However, in the resin film, the ratio of the total content of the polymer component (A), the epoxy resin (B1), the thermosetting agent (B2), the filler (D), and the additive (I) to the total mass of the resin film does not exceed 100 mass%.

Composite Sheet A composite sheet according to one embodiment of the present invention comprises a substrate, a buffer layer provided on the substrate, and a resin film provided on the buffer layer, wherein the resin film is the resin film according to one embodiment of the present invention described above.
As described above, by using the composite sheet of this embodiment, the resin film can be successfully attached to the uneven surface of the object to which it is to be attached, and at this time, the excellent effects of suppressing the resin film from remaining on top of the convex parts of the uneven surface, suppressing the resin film from protruding from its original size, and suppressing the resin film and its cured product from repelling on the uneven surface are obtained.

In this specification, when the 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 substrate in the sheet for forming the first protective film is referred to as a "first substrate."
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 substrate, this substrate is referred to as a "second substrate."

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 substrate 11, a buffer layer 13 provided on the substrate 11, and a resin film 12 provided on the buffer layer 13 (the upper part of the buffer layer 13 on the side opposite the substrate 11).
That is, the composite sheet 1 is constructed by laminating a substrate 11, a buffer layer 13, and a resin film 12 in this order in the thickness direction.
Reference numeral 13a denotes the surface of the buffer layer 13 on which the resin film 12 is provided (hereinafter, sometimes referred to as the "first surface").

FIG. 4 is a cross-sectional view schematically showing another example of the composite sheet of the present embodiment.
The composite sheet 2 shown here is the same as the composite sheet 1 shown in Figure 3, except that it has an adhesive layer 14 between the substrate 11 and the buffer layer 13 (in other words, it has an adhesive layer 14 provided on the substrate 11 and a buffer layer 13 provided on the adhesive layer 14).
That is, the composite sheet 2 is constructed by laminating a substrate 11, an adhesive layer 14, a buffer layer 13, and a resin film 12 in this order in the thickness direction.

The composite sheet of this embodiment is not limited to that shown in FIGS. 3 and 4, and some of the configurations shown in FIGS. 3 and 4 may be changed, deleted, or added, as long as the effects of the present invention are not impaired.
For example, the composite sheet of this embodiment may have a release film on the outermost layer (resin film 12 in the composite sheets shown in FIGS. 3 and 4) 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 (single layer) 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 150 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 according to the purpose, or may have other layers vapor-deposited thereon.
When the resin film is energy ray curable, the substrate is preferably one that transmits energy rays.

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 has a buffering effect against forces applied to the buffer layer and layers adjacent thereto. Here, "layers adjacent thereto" mainly refer to the resin film and layers corresponding to the cured product thereof (for example, protective films such as the first protective film).

The material constituting the buffer layer is not particularly limited.

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

As with the 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 and applying the 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 resin film.

As described above, when a strain ranging from 0.01% to 1000% is applied to a test piece of the buffer layer and the storage modulus Gb of the test piece is measured, and a strain ranging from 0.01% to 1000% is applied to a test piece of the resin film and the storage modulus Gc of the test piece is measured, and Gb and Gc are compared for the same strain, it is more preferable that Gb is equal to or greater than Gc (Gb ≥ Gc) over the entire strain range of 0.01% to 1000%, and 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 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 resin film.

The buffer layer may be a single layer (monolayer) or may consist of two or more layers. If there are multiple layers, these layers may be the same or different from each other, 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.

Resin Film The 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.

Adhesion Layer 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. Therefore, 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).

The adhesive layer may be only one layer (single layer), or may be two or more layers. If there are multiple layers, these layers may be the same or different from each other, and the combination of these layers is not particularly limited.

The thickness of the adhesive layer is preferably 10 to 100 μm, more preferably 25 to 85 μm, and particularly preferably 40 to 70 μm.
Here, "thickness of the adhesive layer" means the thickness of the entire adhesive layer, 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.

<<Adhesion layer-forming composition>>
The adhesion layer can be formed using a composition for forming an adhesion layer containing its constituent materials. For example, the adhesion layer can be formed at the desired location by extruding the composition for forming an adhesion layer onto the surface on which the adhesion layer is to be formed. A more specific method for forming the adhesion 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 composition for forming an adhesion layer is usually the same as the ratio of the contents of the components of the adhesion layer.

<Adhesion layer-forming composition (VI)>
The adhesive layer-forming composition may be, for example, an adhesive layer-forming composition (VI) containing an ethylene-vinyl acetate copolymer resin (EVA).

The density of the ethylene-vinyl acetate copolymer resin is preferably 1100 kg/m ³ or less, more preferably 850 to 1100 kg/m ³ , and particularly preferably 900 to 1000 kg/m ³ .
In this specification, the "density of an ethylene-vinyl acetate copolymer resin" means a value measured in accordance with JIS K7112:1999, unless otherwise specified.

The melting point of the ethylene-vinyl acetate copolymer resin is preferably 50 to 95°C, and more preferably 65 to 85°C.

The melt flow rate (MFR) of the ethylene-vinyl acetate copolymer resin at 190° C. is preferably 1 to 10 g/10 min, more preferably 3 to 8 g/10 min.
In this specification, the "melt flow rate of an ethylene-vinyl acetate copolymer resin" means a value measured in accordance with JIS K7210:1999, unless otherwise specified.

The content of the adhesion layer-forming composition (VI) and the ethylene-vinyl acetate copolymer resin in the adhesion layer is preferably 80 to 100% by mass.

[Other ingredients]
The adhesion layer-forming composition (VI) and the adhesion layer may contain components other than the ethylene-vinyl acetate copolymer resin 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 adhesion layer-forming composition (VI) and the adhesion layer 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 adhesion layer-forming composition (VI) and the other components of the adhesion layer are not particularly limited and may be appropriately selected depending on the purpose.

An example of a preferred composite sheet of the present embodiment includes a substrate, a buffer layer provided on the substrate, and a resin film provided on the buffer layer,
A strain was generated in a test piece of the resin film having a diameter of 25 mm and a thickness of 1 mm under conditions of a temperature of 90°C and a frequency of 1 Hz, and the storage modulus of the test piece was measured. When the storage modulus of the test piece when the strain of the test piece is 1% is defined as Gc1 and the storage modulus of the test piece when the strain of the test piece is 300% is defined as Gc300, the following formula was obtained:
X=Gc1/Gc300
The X value calculated by is 19 or more and less than 10,000,
the resin film is a thermosetting resin film containing a polymer component (A), an epoxy resin (B1), a thermosetting agent (B2), a filler (D), and an additive (I),
the content of the polymer component (A) in the resin film is 5 to 25% by mass relative to the total mass of the resin film;
the content of the thermosetting agent (B2) in the resin film is 0.1 to 500 parts by mass per 100 parts by mass of the epoxy resin (B1);
a total content of the epoxy resin (B1) and the thermosetting agent (B2) in the resin film is 600 to 1000 parts by mass per 100 parts by mass of the polymer component (A);
The content ratio of the filler (D) in the resin film relative to the total mass of the resin film is 5 to 45 mass%,
The content ratio of the additive (I) in the resin film relative to the total mass of the resin film is 0.5 to 10 mass%,
However, in the resin film, the ratio of the total content of the polymer component (A), the epoxy resin (B1), the thermosetting agent (B2), the filler (D), and the additive (I) to the total mass of the resin film does not exceed 100 mass%.

Another example of a preferred composite sheet of the present embodiment includes a substrate, a buffer layer provided on the substrate, and a resin film provided on the buffer layer,
A strain was generated in a test piece of the resin film having a diameter of 25 mm and a thickness of 1 mm under conditions of a temperature of 90°C and a frequency of 1 Hz, and the storage elastic modulus of the test piece of the resin film was measured. When the storage elastic modulus of the test piece of the resin film when the strain of the test piece of the resin film was 1% was defined as Gc1, and when the storage elastic modulus of the test piece of the resin film when the strain of the test piece of the resin film was 300% was defined as Gc300, the following formula was obtained:
X=Gc1/Gc300
The X value calculated by is 19 or more and less than 10,000,
A composite sheet in which strain is generated in a test piece of the buffer layer having a diameter of 25 mm and a thickness of 1 mm under conditions of a temperature of 90°C and a frequency of 1 Hz, and the storage modulus of the test piece of the buffer layer is measured, and when the storage modulus of the test piece of the buffer layer when the strain of the test piece of the buffer layer is 300% is defined as Gb300, Gb300 is equal to or greater than Gc300 is an example.

Yet another example of a preferable composite sheet of the present embodiment includes a substrate, a buffer layer provided on the substrate, and a resin film provided on the buffer layer,
A strain was generated in a test piece of the resin film having a diameter of 25 mm and a thickness of 1 mm under conditions of a temperature of 90°C and a frequency of 1 Hz, and the storage elastic modulus of the test piece of the resin film was measured. When the storage elastic modulus of the test piece of the resin film when the strain of the test piece of the resin film was 1% was defined as Gc1, and when the storage elastic modulus of the test piece of the resin film when the strain of the test piece of the resin film was 300% was defined as Gc300, the following formula was obtained:
X=Gc1/Gc300
The X value calculated by is 19 or more and less than 10,000,
A composite sheet in which a strain in the range of 0.01% to 1000% is generated in a test piece of the buffer layer having a diameter of 25 mm and a thickness of 1 mm under conditions of a temperature of 90°C and a frequency of 1 Hz, the storage modulus Gb of the test piece of the buffer layer is measured, and a strain in the range of 0.01% to 1000% is generated in a test piece of the resin film, the storage modulus Gc of the test piece of the resin film is measured, and when Gb and Gc are compared for the same strain, Gb is equal to or greater than Gc over the entire range of 0.01% to 1000% strain.

Yet another example of a preferable composite sheet of the present embodiment includes a substrate, a buffer layer provided on the substrate, and a resin film provided on the buffer layer,
A strain was generated in a test piece of the resin film having a diameter of 25 mm and a thickness of 1 mm under conditions of a temperature of 90°C and a frequency of 1 Hz, and the storage elastic modulus of the test piece of the resin film was measured. When the storage elastic modulus of the test piece of the resin film when the strain of the test piece of the resin film was 1% was defined as Gc1, and when the storage elastic modulus of the test piece of the resin film when the strain of the test piece of the resin film was 300% was defined as Gc300, the following formula was obtained:
X=Gc1/Gc300
The X value calculated by is 19 or more and less than 10,000,
a strain is generated in a test piece of the buffer layer having a diameter of 25 mm and a thickness of 1 mm under conditions of a temperature of 90°C and a frequency of 1 Hz, and the storage modulus of the test piece of the buffer layer is measured; when the storage modulus of the test piece of the buffer layer when the strain of the test piece of the buffer layer is 300% is defined as Gb300, Gb300 is equal to or greater than Gc300;
the resin film is a thermosetting resin film containing a polymer component (A), an epoxy resin (B1), a thermosetting agent (B2), a filler (D), and an additive (I),
the content of the polymer component (A) in the resin film is 5 to 25% by mass relative to the total mass of the resin film;
the content of the thermosetting agent (B2) in the resin film is 0.1 to 500 parts by mass per 100 parts by mass of the epoxy resin (B1);
a total content of the epoxy resin (B1) and the thermosetting agent (B2) in the resin film is 600 to 1000 parts by mass per 100 parts by mass of the polymer component (A);
The content ratio of the filler (D) in the resin film relative to the total mass of the resin film is 5 to 45 mass%,
The content ratio of the additive (I) in the resin film relative to the total mass of the resin film is 0.5 to 10 mass%,
However, in the resin film, the ratio of the total content of the polymer component (A), the epoxy resin (B1), the thermosetting agent (B2), the filler (D), and the additive (I) to the total mass of the resin film does not exceed 100 mass%.

Yet another example of a preferable composite sheet of the present embodiment includes a substrate, a buffer layer provided on the substrate, and a resin film provided on the buffer layer,
A strain was generated in a test piece of the resin film having a diameter of 25 mm and a thickness of 1 mm under conditions of a temperature of 90°C and a frequency of 1 Hz, and the storage elastic modulus of the test piece of the resin film was measured. When the storage elastic modulus of the test piece of the resin film when the strain of the test piece of the resin film was 1% was defined as Gc1, and when the storage elastic modulus of the test piece of the resin film when the strain of the test piece of the resin film was 300% was defined as Gc300, the following formula was obtained:
X=Gc1/Gc300
The X value calculated by is 19 or more and less than 10,000,
a test piece of the buffer layer having a diameter of 25 mm and a thickness of 1 mm is strained in the range of 0.01% to 1000% under conditions of a temperature of 90°C and a frequency of 1 Hz, and the storage modulus Gb of the test piece of the buffer layer is measured; a test piece of the resin film is strained in the range of 0.01% to 1000%, and the storage modulus Gc of the test piece of the resin film is measured; and when Gb and Gc are compared for the same strain, Gb is equal to or greater than Gc over the entire range of 0.01% to 1000%,
the resin film is a thermosetting resin film containing a polymer component (A), an epoxy resin (B1), a thermosetting agent (B2), a filler (D), and an additive (I),
the content of the polymer component (A) in the resin film is 5 to 25% by mass relative to the total mass of the resin film;
the content of the thermosetting agent (B2) in the resin film is 0.1 to 500 parts by mass per 100 parts by mass of the epoxy resin (B1);
a total content of the epoxy resin (B1) and the thermosetting agent (B2) in the resin film is 600 to 1000 parts by mass per 100 parts by mass of the polymer component (A);
The content ratio of the filler (D) in the resin film relative to the total mass of the resin film is 5 to 45 mass%,
The content ratio of the additive (I) in the resin film relative to the total mass of the resin film is 0.5 to 10 mass%,
However, in the resin film, the ratio of the total content of the polymer component (A), the epoxy resin (B1), the thermosetting agent (B2), the filler (D), and the additive (I) to the total mass of the resin film does not exceed 100 mass%.

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 of forming each layer is as described above.

For example, a composite sheet constructed by laminating a substrate, a buffer layer, and a 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 resin film-forming composition described above is then coated on the release-treated surface of a release film, and dried as necessary to laminate a resin film. The resin film on the release film is then bonded to the buffer layer on the substrate, yielding a composite sheet in which the substrate, buffer layer, resin film, and release film are laminated in this order. The release film on the resin film can be removed when the composite sheet is 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.

For example, a composite sheet constructed by laminating a substrate, an adhesive layer, a buffer layer, and a resin film in this order in the thickness direction can be produced by the method shown below.
That is, the adhesive layer-forming composition and the buffer layer-forming composition are co-extruded onto the substrate, thereby laminating the adhesive layer and buffer layer in this order on the substrate. Then, using the same method as above, a resin film is separately laminated on a release film. Next, the resin film on the release film is bonded to the substrate and the buffer layer on the adhesive layer, thereby obtaining a composite sheet in which the substrate, adhesive layer, buffer layer, resin film, and release film are laminated in this order. The release film on the resin film can be removed when the composite sheet is used.

◇ Manufacturing method of semiconductor device (method of using resin film and composite sheet)
As explained above, the resin film of this embodiment has an extremely excellent property in that, when attached to an uneven surface of an object, it can cover the entire uneven surface while penetrating the convex portions and exposing the upper portions of the convex portions. In other words, the resin film of this embodiment is suitable for attachment to the uneven surface of an object having an uneven surface.
The 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 bump-bearing surface (bump-formed surface) of the semiconductor chip. In this case, the uneven surface is the bump-formed surface of the semiconductor chip, and the convex portions are the bumps. The semiconductor chip with the first protective film is suitable for use in manufacturing a semiconductor device by flip-chip bonding the bumps to a substrate.
The resin film of this embodiment is suitable for use in the form of the composite sheet described above.
A method for manufacturing a semiconductor device using the composite sheet will now be described.

A method for manufacturing a semiconductor device according to one embodiment of the present invention includes: an attachment step in which the curable resin film in the composite sheet according to the embodiment of the present invention is attached to a bump-bearing surface of a semiconductor wafer (bump-forming surface) and the tops of the bumps are protruded from the resin film, thereby providing the composite sheet on the semiconductor wafer; a removal step in which, after the attachment step, layers of the composite sheet other than the resin film are removed from the resin film; a curing step in which, after the removal step, the resin film is cured to form a first protective film; a dividing step in which, after the curing step, the semiconductor wafer is divided to produce semiconductor chips; a cutting step in which, after the curing step, the first protective film is cut; and a mounting step in which the semiconductor chips obtained after the dividing and cutting steps and the first protective film provided on the bump-bearing surface of the semiconductor chip, the tops of the bumps of which protrude from the first protective film, are flip-chip connected to a substrate at the tops of the bumps.

5A to 5D are cross-sectional views that schematically show an example of a method for manufacturing a semiconductor device when the composite sheet 1 shown in FIG. 3 is used.
Here, since the curable resin film is used for forming the first protective film, the "composite sheet 1" will be referred to as the "sheet 1 for forming the first protective film" and the "substrate 11" will be referred to as the "first substrate 11".

<Attachment process>
In the bonding process, as shown in Figures 5A to 5B, the curable resin film 12 in the first protective film forming sheet 1 is bonded to the bump forming surface 9a of the semiconductor wafer 9, and the tops 9101 of the bumps 91 are caused to protrude from the curable resin film 12, thereby providing the first protective film forming sheet 1 on the semiconductor wafer 9.

In the bonding process, for example, as shown in Figure 5A, the first protective film forming sheet 1 is first positioned so that its curable resin film 12 faces the bump formation surface 9a of the semiconductor wafer 9.

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 remaining of the curable resin film 12 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 remaining of the curable resin film 12 on the bump 91 can be further improved.
In this specification, the "width of a bump" 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-forming 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 remaining of the curable resin film 12 on the upper parts of the bumps 91 can be further improved.
In this specification, the "distance between adjacent bumps" means the minimum distance between the surfaces of adjacent bumps.

Next, in the bonding step, the curable 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 curable 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. At this time, by heating the curable resin film 12, the curable resin film 12 softens and spreads between the bumps 91 so as to cover the bumps 91, adheres to the bump-forming surface 9a, and covers 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.
As a result of the above, the curable resin film 12 in the first protective film forming sheet 1 is attached to the bump formation surface 9a of the semiconductor wafer 9, as shown in FIG. 5B.

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 (curable resin film 12) when it is pressed onto the semiconductor wafer 9 may be a temperature at which the curable resin film 12 is not cured at all or does not cure excessively, and may be, for example, 80 to 100°C.
However, the heating temperature is more preferably 85 to 95°C, since this more effectively suppresses the remaining of the curable resin film 12 on the top of the bump 91, the more effectively suppresses the protrusion of the curable resin film 12 on the bump-forming surface 9a, and the more effectively suppresses the repelling of the curable resin film 12 on the bump-forming surface 9a.

The pressure when the first protective film forming sheet 1 (curable 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.
However, it is more preferable that the pressure be 0.3 to 1 MPa, since this will improve the effects of suppressing the remaining of the curable resin film 12 on the top of the bump 91, suppressing the protrusion of the curable resin film 12 on the bump forming surface 9a, and suppressing the repelling of the curable resin film 12 on the bump forming surface 9a.

As described above, when the first protective film forming sheet 1 is pressure-bonded to the semiconductor wafer 9, the curable resin film 12 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 curable resin film 12 and the first surface 13a of the buffer layer 13 are deformed concavely. Then, as pressure from the bumps 91 continues to be applied, the curable resin film 12 tears. Finally, when the first surface 12a of the curable resin film 12 is 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 curable resin film 12. Note that, in this final stage, the upper portion 910 of the bump 91 typically does not penetrate the buffer layer 13. This is because the buffer layer 13 provides a buffering effect against the pressure applied by the bumps 91.

As shown in Figure 5B, at the stage when the attachment process is completed, no or almost no curable resin film 12 remains on the upper portion 910 including the top portion 9101 of the bump 91, and the remaining curable resin film 12 is suppressed on the upper portion 910 of the bump 91. In this specification, unless otherwise specified, "almost no curable resin film remains on the upper portion of the bump" means that although a small amount of curable resin film remains on the upper portion 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 having this bump is flip-chip connected to the substrate.

Furthermore, once the bonding process is completed, the curable resin film 12 is prevented from protruding from its original size, thereby preventing the curable resin film 12 from protruding from the bump-forming surface 9a of the semiconductor wafer 9.

Furthermore, once the application process is complete, repelling of the curable resin film 12 onto the bump-forming surface 9a is suppressed. More specifically, with the curable resin film 12 provided on the bump-forming surface 9a, the phenomenon of regions of the bumps 91 other than their upper portions 910 (e.g., base portions near the bump-forming surface 9a) or regions of the bump-forming surface 9a near the bumps 91 being unintentionally exposed without being covered by the curable resin film 12 is suppressed.

In this way, the reason why the remaining curable resin film 12 is suppressed on the upper part 910 of the bump 91, the protrusion of the curable resin film 12 on the bump forming surface 9a is suppressed, and the repelling of the curable resin film 12 on the bump forming surface 9a is suppressed is because, as explained above, the curable resin film 12 satisfies the X value condition (19≦X value<10,000).

After the above-mentioned attachment process, if necessary, the surface (back surface) 9b of the semiconductor wafer 9 opposite the bump formation surface 9a is ground, and then a second protective film formation sheet (not shown) is attached to this back surface 9b.

<Removal process>
5C , in the removing step after the attaching step, the layers of the first protective film-forming sheet 1 other than the curable resin film 12 are removed from the curable resin film 12. More specifically, the layers to be removed here are the first substrate 11 and the buffer layer 13.
By carrying out the removing step, a semiconductor wafer with a resin film is obtained, which includes the semiconductor wafer 9 and the curable resin film 12 provided on the bump formation surface 9a of the semiconductor wafer 9.

<Curing process>
After the removing step, in the curing step, the curable resin film 12 is cured to form a first protective film.
In the curing step, if the curable resin film 12 is thermosetting, the curable resin film 12 is cured by heating, and if the curable resin film 12 is energy ray curable, the curable resin film 12 is cured by irradiating with energy rays. The heating conditions and energy ray irradiation conditions at this time are as described above.

<Dividing process, cutting process>
After the hardening step, in the dividing step, the semiconductor wafer 9 is divided to produce semiconductor chips 9', and in the cutting step, the first protective film is cut.
The dividing step and cutting step can be carried out by known methods.

The order in which the dividing step and the cutting step are performed is not particularly limited, but it is preferable to perform the dividing step and the cutting step simultaneously, or to perform the dividing step and the cutting step in that order. When the dividing step and the cutting step are performed in this order, for example, the dividing step may be performed by a known dicing method, and then the cutting step may be performed immediately thereafter.
In the cutting step, the first protective film is cut along the planned or completed dividing points of the semiconductor wafer 9 (in other words, along the outer periphery of the semiconductor chip 9').

By performing the curing process, dividing process, and cutting process, a semiconductor chip 9120' with a first protective film is obtained, as shown in Figure 5D, which is composed of a semiconductor chip 9' and a first protective film (sometimes simply referred to as the "first protective film" in this specification) 120' after cutting, which is provided on the bump-forming surface 9a' of the semiconductor chip 9'.

In the semiconductor chip 9120' with the first protective film, the tops 9101 of the bumps 91 protrude from the first protective film 120', and the first protective film is not or hardly adheres to the upper parts 910 including the tops 9101 of the bumps 91, thereby suppressing adhesion of the first protective film to the upper parts 910 of the bumps 91.
Furthermore, in the semiconductor chip 9120' with the first protective film, the first protective film 120' is prevented from protruding from the bump formation 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.

<Mounting process>
After the dividing and cutting steps, in the mounting step, the semiconductor chip 9120′ with the first protective film is flip-chip connected to the substrate at the tops 9101 of the bumps 91 (not shown). At this time, the semiconductor chip 9120′ with the first protective film is connected to the circuit formation surface of the substrate.
Since the adhesion of the first protective film to the upper portions 910 of the bumps 91 in the semiconductor chip 9120' with the first protective film is suppressed, the degree of electrical connection between the semiconductor chip 9' and the substrate is high in this step.

When the second protective film formation sheet is used, the semiconductor chip 9120' with the first protective film is picked up by separating it from the dicing sheet (not shown) in the second protective film formation sheet prior to flip-chip connection.
The semiconductor chip 9120' with the first protective film can be picked up by a known method.
When the second protective film forming sheet is used, the semiconductor chip 9' in the semiconductor chip 9120' with the first protective film has the second protective film after cutting on the rear surface 9b' (not shown).

If the film for forming a second protective film in the sheet for forming a second protective film is curable, the film for forming a second protective film is cured at an appropriate time depending on its type to form the second protective film. The second protective film is then cut at an appropriate time depending on its type.

The film for forming the second protective film can be cured in the same manner as the curable resin film 12, and may be cured simultaneously with the curable resin film 12 or separately from the curable resin film 12.

The second protective film can be cut in the same manner as the first protective film.
The order in which the dividing step and the cutting of the second protective film are performed is not particularly limited, but it is preferable to perform the dividing step and the cutting of the second protective film simultaneously, or to perform the cutting of the second protective film after the dividing step. When the dividing step and the cutting of the second protective film are performed in this order, for example, the dividing step may be performed by a known dicing method, and then the cutting of the second protective film may be performed immediately and continuously thereafter.
The second protective film is cut along the planned or completed dividing points of the semiconductor wafer 9 (in other words, along the outer periphery of the semiconductor chip 9').

Then, using the circuit board thus obtained and already equipped with the semiconductor chip 9', a semiconductor package is produced according to a known method, and the desired semiconductor device can be manufactured using this semiconductor package (not shown).

Here, we have explained the use of the composite sheet (first protective film forming sheet) 1 shown in Figure 3, but even when using other embodiments of composite sheets, such as composite sheet 2 shown in Figure 4, this composite sheet will achieve the same effects as when composite sheet 1 is used.

6A to 6D are cross-sectional views schematically showing an example of a method for manufacturing a semiconductor device when the composite sheet (first protective film forming sheet) 2 shown in FIG. 4 is used.
Even when using the first protective film forming sheet 2, in the attachment process, as shown in Figures 6A to 6B, the curable resin film 12 in the first protective film forming sheet 2 is attached to the bump formation surface 9a of the semiconductor wafer 9, and the top portions 9101 of the bumps 91 protrude from the curable resin film 12, thereby providing the first protective film forming sheet 2 on the semiconductor wafer 9.

In the bonding process, for example, as shown in Figure 6A, the first protective film forming sheet 2 is first positioned so that its curable resin film 12 faces the bump formation surface 9a of the semiconductor wafer 9.

Next, in the bonding step, the curable resin film 12 is brought into contact with the bumps 91 on the semiconductor wafer 9, and the first protective film-forming sheet 2 is pressed against the semiconductor wafer 9. This causes the first surface 12a of the curable resin film 12 to be sequentially pressure-bonded to the surfaces 91a of the bumps 91 and the bump-forming surface 9a of the semiconductor wafer 9. As a result, the curable resin film 12 in the first protective film-forming sheet 2 is bonded to the bump-forming surface 9a of the semiconductor wafer 9, as shown in FIG. 6B .
At this time, the first protective film forming sheet 2 can be pressure-bonded to the semiconductor wafer 9 in the same manner as when the first protective film forming sheet 1 is used.

As described above, when the first protective film-forming sheet 2 is pressure-bonded to the semiconductor wafer 9, the curable resin film 12 and the buffer layer 13 in the first protective film-forming sheet 2 are subjected to pressure from the bumps 91, and initially, the first surface 12a of the curable resin film 12 and the first surface 13a of the buffer layer 13 are deformed into a concave shape. Then, in this state, the curable resin film 12, to which pressure is applied from the bumps 91, breaks. Finally, at the stage where the first surface 12a of the curable resin film 12 is 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 curable resin film 12. In this final stage, the upper portion 910 of the bump 91 usually does not penetrate the buffer layer 13.
Furthermore, by using the first protective film forming sheet 2, as described above, in the process of bonding the curable resin film 12 to the bump forming surface 9a of the semiconductor wafer 9, the adhesion layer 14 highly suppresses peeling of the first substrate 11 and the buffer layer 13, and the laminated structure of the first substrate 11, adhesion layer 14 and buffer layer 13 is maintained more stably.

As shown in Figure 6B, at the stage when the bonding process is completed, due to the same effect as in the case of the first protective film forming sheet 1, no or almost no curable resin film 12 remains on the upper part 910 including the top part 9101 of the bump 91.
Furthermore, at the stage when the above-mentioned bonding process is completed, the same action as in the case of the first protective film forming sheet 1 prevents the curable resin film 12 from protruding from its original size, thereby preventing the curable resin film 12 from protruding from the bump forming surface 9a of the semiconductor wafer 9.
Furthermore, at the stage where the attaching step is completed, the same action as in the case of the first protective film forming sheet 1 prevents the curable resin film 12 from repelling on the bump forming surface 9a.

After the above-mentioned attachment process, if necessary, the surface (back surface) 9b of the semiconductor wafer 9 opposite the bump formation surface 9a is ground, and then a second protective film formation sheet (not shown) is attached to this back surface 9b.

6C , in the removing step after the attaching step, the layers of the first protective film-forming sheet 2 other than the curable resin film 12 are removed from the curable resin film 12. More specifically, the layers to be removed here are the first substrate 11, the adhesion layer 14, and the buffer layer 13.
By carrying out the removing step, a semiconductor wafer with a resin film is obtained, which is the same as that obtained when the first protective film forming sheet 1 is used.

Thereafter, a semiconductor device can be manufactured in the same manner as when the first protective film forming sheet 1 is used.
That is, after the removing step, the curable resin film 12 is cured in the curing step in the same manner as when the first protective film-forming sheet 1 is used, thereby forming the first protective film.
After the hardening process, in the dividing process, the semiconductor wafer 9 is divided to produce semiconductor chips 9' in the same manner as when using the first protective film forming sheet 1, and in the cutting process, the first protective film is cut.
By performing the curing step and the dividing step, a semiconductor chip 9120' with a first protective film is obtained, as shown in Fig. 6D. The semiconductor chip 9120' with a first protective film obtained here is the same as that obtained when the first protective film-forming sheet 1 is used.
Furthermore, the mounting process is carried out in the same manner as when using the first protective film forming sheet 1, and the resulting circuit board with the semiconductor chip 9' mounted thereon is used to create a semiconductor package, thereby manufacturing the desired semiconductor device (not shown).

In the method for manufacturing a semiconductor device according to this embodiment, whether or not the curable resin film or protective film remains on the top of the bumps can be confirmed by, for example, obtaining SEM image data of the bumps.
In addition, whether or not the curable resin film is protruding from the bump-forming surface of the semiconductor wafer and whether or not the curable resin film is repelling from the bump-forming surface can both be confirmed, for example, by obtaining SEM image data of the relevant area on the bump-forming surface of the semiconductor wafer.

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 resin film-forming composition>
The raw materials used in the production of the 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 BL-10" manufactured by Sekisui Chemical Co., Ltd., weight average molecular weight 25,000, glass transition temperature 59°C).
(A)-2: Acrylic resin (weight average molecular weight: 800,000, glass transition temperature: −28° C.) obtained by copolymerizing butyl acrylate (55 parts by mass), methyl acrylate (10 parts by mass), glycidyl methacrylate (20 parts by mass), and 2-hydroxyethyl acrylate (15 parts by mass).

(wherein l ₁ is about 28, m ₁ is 1 to 3, and n ₁ is an integer from 68 to 74.)

[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: Liquid bisphenol F epoxy resin ("YL983U" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: 165 to 175 g/eq)
(B1)-3: Polyfunctional aromatic epoxy resin (Nippon Kayaku Co., Ltd. "EPPN-502H"), epoxy equivalent 158 to 178 g/eq)
(B1)-4: Dicyclopentadiene-type epoxy resin (DIC Corporation, "Epicron HP-7200HH", epoxy equivalent: 254 to 264 g/eq)
[Thermal curing agent (B2)]
(B2)-1: O-cresol novolak resin (DIC Corporation, "Phenolite KA-1160")
(B2)-2: Novolac phenolic resin ("BRG-556" manufactured by Showa Denko K.K.)
[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: Rheology control agent (polyhydroxycarboxylic acid ester, "BYK-R606" manufactured by BYK Corporation)
(I)-2: Surfactant (acrylic polymer, "BYK-361N" manufactured by BYK Corporation)
(I)-3: Silicone oil (aralkyl-modified silicone oil, "XF42-334" manufactured by Momentive Performance Materials Japan, Inc.)
[Curing accelerator (C)]
(C)-1: 2-phenyl-4,5-dihydroxymethylimidazole ("Curezol 2PHZ-PW" manufactured by Shikoku Chemicals Corporation)

[Example 1]
<<Production of 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 (350 parts by mass), epoxy resin (B1)-4 (270 parts by mass), (B2)-1 (190 parts by mass), curing accelerator (C)-1 (2 parts by mass), filler (D)-1 (90 parts by mass), and additive (I)-1 (9 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 Sheet for Forming First Protective 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 30 μm.

A laminate sheet ("E-9485" manufactured by Lintec Corporation, thickness 485 μm) corresponding to a laminate of a first substrate, an adhesive layer, and a buffer layer was used, and the buffer 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 Figure 4, in which the first substrate, adhesive layer, buffer layer, thermosetting resin film, and release film were laminated in this order in the thickness direction.

<<Evaluation of the sheet for forming the first protective film>>
<Measurement of Gc1 and Gc300 of Thermosetting Resin Film and Calculation of X Value>
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 1 mm-thick thermosetting resin film test piece.
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 test piece of the thermosetting resin film obtained above was placed on this location, and the test piece was fixed to the location by pressing a measuring jig against the upper surface of the test piece.
Next, the strain generated in the test piece was increased stepwise from 0.01% to 1000% at a temperature of 90°C and a measurement frequency of 1 Hz, and the storage modulus Gc of the test piece was measured. 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>
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 test piece with a release film.
The entire exposed surface of the obtained 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 as viewed from above the backgrind tape side.
As shown here, the obtained laminate 101 is composed of a backgrind tape 7, a 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 obtained laminate, and the newly exposed surface of the test piece (in other words, the surface of the test piece opposite to the side provided with the backgrind tape) was pressed against one surface of a 12-inch diameter silicon wafer, thereby attaching the test piece to the surface of the silicon wafer. At this time, the test piece was attached to the surface of the silicon wafer 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/sec, an attachment pressure of 0.5 MPa, and a roller attachment height of -200 μm, while heating the thermosetting resin film.
Next, for the test piece with back-grinding tape attached to the silicon wafer, the maximum length of a line segment connecting two different points on the outer periphery was measured, and the measured value (maximum length of the line segment) was used to calculate the protrusion amount (mm) of the test piece (in other words, the thermosetting resin film) by the method described with reference to Figure 2.

<Checking whether or not the thermosetting resin film remains on top of the bump>
The release film was removed from the first protective film-forming sheet obtained above, and the surface (exposed surface) of the thermosetting resin film thus exposed was pressed against the bump-forming surface of an 8-inch diameter semiconductor wafer. This resulted in the first protective film-forming sheet from which the release film had been removed being attached to the bump-forming surface of the semiconductor wafer. The semiconductor wafer used had bumps with a height of 210 μm, a width of 250 μm, and a distance between the bumps of 400 μm. The first protective film-forming sheet was attached while being heated using an attachment device (a roller-type laminator, manufactured by Lintec Corporation, model RAD-3510 F/12) under conditions of a table temperature of 90°C, an attachment speed of 2 mm/sec, an attachment pressure of 0.5 MPa, and a roller attachment height of -200 μm.
Next, the first substrate, the adhesive layer, and the buffer layer were removed from the thermosetting resin film using a multi-wafer mounter ("RAD-2700 F/12" manufactured by Lintec Corporation) to expose the thermosetting resin film.
Next, the surfaces of the bumps on the semiconductor wafer were observed using a scanning electron microscope (SEM, Keyence Corporation "VE-9700") from a direction perpendicular to the bump-forming surface of the semiconductor wafer at an angle of 60° to check whether any thermosetting resin film remained on the top of the bumps. The results are shown in Table 1.

<Checking for repelling of the thermosetting resin film on the bump formation surface>
Using the same method as in the above-mentioned "Confirming whether or not the thermosetting resin film remains on top of the bumps," the same semiconductor wafer was used, a first protective film forming sheet was attached to the bump-forming surface, and the first substrate, adhesion layer, and buffer layer were removed from the thermosetting resin film.
Next, the thermosetting resin film attached to the semiconductor wafer 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 2 hours, and an internal furnace pressure of 0.5 MPa, thereby thermally curing the thermosetting resin film.
Next, using a scanning electron microscope (SEM, Keyence Corporation "VE-9700"), the entire laminate of the cured product of the thermosetting resin film (in other words, the first protective film) and the semiconductor wafer was observed from the cured product side. If there was an area where the base of the bump or the bump-formed surface of the semiconductor wafer could be directly observed, it was judged as "cissing present," and if there was no area where the base of the bump or the bump-formed surface of the semiconductor wafer could be directly observed, it was judged as "cissing absent."

[Example 2, Comparative Examples 1 to 3]
<<Production and Evaluation of Sheet for Forming First Protective Film>>
A first protective film-forming sheet was produced and evaluated in the same manner as in Example 1, except that either or both of the types and amounts of the components blended during the production of the thermosetting resin film-forming composition were changed 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 Examples 1 and 2, the amount of protrusion of the thermosetting resin film was 0 mm (no protrusion of the thermosetting resin film was observed), and no remaining thermosetting resin film was observed on the top of the bumps.
Furthermore, in Examples 1 and 2, no repellency of the thermosetting resin film was observed on the bump-forming surface, demonstrating that the basic properties of the thermosetting resin film were good. At the same time, when the top of the bump was observed, no thermosetting resin film was observed.
In Examples 1 and 2, the X value was 29 to 65.

In contrast to this, in Comparative Example 1, the extrusion of the thermosetting resin film was not suppressed.
In Comparative Example 1, the X value was 18, which was clearly smaller than those in Examples 1 and 2. This was because Gc1 in Comparative Example 1 was too low.

In Comparative Example 2, cissing of the thermosetting material of the thermosetting resin film was observed on the bump formation surface, and the basic properties of the thermosetting resin film were poor.
In Comparative Example 2, the X value was 10,000 or more, which was clearly larger than those in Examples 1 and 2. This was because Gc300 was too low in Comparative Example 2. In Comparative Example 2, Gc300 was below the detection limit and could not be identified, and the X value could only be identified as being 10,000 or more.

In Comparative Example 3, residual thermosetting resin film was found on the top of the bump. When checking for the presence or absence of cissing of the thermoset product of the thermosetting resin film, the top of the bump was also observed, and as a result, the thermoset product of the thermosetting resin film was also found.
In Comparative Example 3, the X value was 18, which was clearly smaller than those in Examples 1 and 2. This was because Gc300 in Comparative Example 3 was too high.

In Examples 1 and 2, for the buffer layer in the laminate sheet, test pieces (disk-shaped, 25 mm in diameter and 1 mm in thickness) similar to the test pieces of the thermosetting resin film described above were prepared, and the strain generated in the test pieces of the buffer layer was increased stepwise in the range of 0.01% to 1000%, as in the case of the test pieces of the thermosetting resin film, and the storage modulus Gb of the test pieces of the buffer layer was measured.
As a result, when Gb and Gc were compared for the same strain, Gb was equal to or greater than Gc (Gb≧Gc) in the entire strain range of 0.01% to 1000%.

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.

1, 2... composite sheet (sheet for forming first protective film), 11... substrate (first substrate), 12... resin film (curable resin film), 12a... first surface of resin film (curable resin film), 120'... first protective film (first protective film after cutting), 13... buffer layer, 13a... first surface of buffer layer, 14... adhesion layer, 9... semiconductor wafer, 9a... bump-forming surface of semiconductor wafer, 9'... semiconductor chip, 9a'... bump-forming surface of semiconductor chip, 91... bump, 91a... surface of bump, 910... upper part of bump, 9101... top of bump

Claims (4)

A thermosetting resin film,
the resin film contains a polymer component (A), an epoxy resin (B1), a thermosetting agent (B2), a filler (D), and an additive (I),
the polymer component (A) is polyvinyl acetal,
the additive (I) is a rheology control agent, a surfactant, or a silicone oil;
the content of the polymer component (A) in the resin film is 5 to 25% by mass relative to the total mass of the resin film;
a total content of the epoxy resin (B1) and the thermosetting agent (B2) in the resin film is 600 to 1000 parts by mass per 100 parts by mass of the polymer component (A);
The content of the additive (I) in the resin film is 0.5 to 10% by mass relative to the total mass of the resin film,
A strain was generated in a test piece of the resin film having a diameter of 25 mm and a thickness of 1 mm under conditions of a temperature of 90°C and a frequency of 1 Hz, and the storage modulus of the test piece was measured. When the storage modulus of the test piece when the strain of the test piece is 1% is defined as Gc1, and the storage modulus of the test piece when the strain of the test piece is 300% is defined as Gc300, the following formula was obtained:
X=Gc1/Gc300
The resin film has an X value calculated by the above formula: 19 or more and less than 10,000. The resin film according to claim 1, wherein the resin film is intended for application to an uneven surface. A substrate, a buffer layer provided on the substrate, and a resin film provided on the buffer layer,
A composite sheet, wherein the resin film is the resin film according to claim 1 or 2. a bonding step of bonding the resin film in the composite sheet according to claim 3 to a surface of a semiconductor wafer having bumps, with the tops of the bumps protruding from the resin film, thereby providing the composite sheet on the semiconductor wafer;
a removing step of removing layers of the composite sheet other than the resin film from the resin film after the attaching step;
a curing step of thermally curing the resin film to form a first protective film after the removing step;
a dividing step of dividing the semiconductor wafer after the curing step to produce semiconductor chips;
a cutting step of cutting the first protective film after the curing step;
A method for manufacturing a semiconductor device, comprising: a mounting process in which the semiconductor chip with the first protective film, which is obtained after the dividing process and the cutting process, and a first protective film provided on a surface of the semiconductor chip having bumps, and the tops of the bumps protruding from the first protective film, are flip-chip connected to a substrate at the tops of the bumps.