JP7704674B2 - Manufacturing method of the third laminate - Google Patents

Description

The present invention relates to a method for producing a third laminate, and more particularly to a method for producing a third laminate in which a workpiece such as a semiconductor wafer, a film for forming a back surface protection film, and a support sheet are laminated in this order.
This application claims priority based on Japanese Patent Application No. 2019-086303, filed on April 26, 2019, the contents of which are incorporated herein by reference.

In recent years, semiconductor devices have been manufactured using a mounting method known as the face-down method. In the face-down method, a semiconductor chip is used that has electrodes such as bumps on its circuit surface, and these electrodes are bonded to a substrate. For this reason, the back surface of the semiconductor chip, which is opposite the circuit surface, may be exposed.

A resin film containing an organic material is formed on the back surface of the exposed semiconductor chip as a back surface protective film, and the semiconductor chip with the back surface protective film may be incorporated into a semiconductor device. The back surface protective film is used to prevent cracks from occurring in the semiconductor chip after the dicing process and packaging (for example, Patent Documents 1 and 2).

Such a semiconductor chip with a back surface protective film is manufactured, for example, through the process shown in Figure 9. That is, a method is known in which a film for forming a back surface protective film 13 is laminated on the back surface 8b of a semiconductor wafer 8 having a circuit surface (Figure 9 (A)), the film for forming a back surface protective film 13 is heat-cured or energy-ray-cured to form a back surface protective film 13' (Figure 9 (B)), the back surface protective film 13' is laser-marked (Figure 9 (C)), a support sheet 10 is laminated on the back surface protective film 13' (Figure 9 (D)), the semiconductor wafer 8 and the back surface protective film 13' are diced to form a semiconductor chip 7 with a back surface protective film (Figures 9 (E) and 9 (F)), and the semiconductor chip 7 with a back surface protective film is picked up from the support sheet 10 (Figure 9 (G)). The order of the curing step and the laser marking step is arbitrary, and the film 13 for forming a back surface protective film may be laminated on the back surface 8b of the semiconductor wafer 8 having a circuit surface (FIG. 9(A)), the film 13 for forming a back surface protective film may be laser-marked, and then the film 13 for forming a back surface protective film may be thermally cured or energy ray cured to form a back surface protective film 13', and then the steps of FIG. 9(D) to FIG. 9(G) may be performed. The first lamination step of laminating the film 13 for forming a back surface protective film on the back surface 8b of the semiconductor wafer 8 in FIG. 9(A) and the second lamination step of laminating the support sheet 10 on the back surface protective film 13' in FIG. 9(D) have conventionally been performed by separate devices.

In addition, a composite sheet for forming a protective film, in which a film 13 for forming a back surface protective film and a support sheet 10 are integrated, is used in the manufacture of semiconductor chips with a back surface protective film (for example, Patent Document 2).

A method for manufacturing a semiconductor chip with a back surface protective film using a composite sheet for forming a protective film includes, for example, the steps shown in Fig. 10. That is, a method is known in which a film for forming a back surface protective film 13 of a composite sheet for forming a protective film 1, which is a laminate of a film for forming a back surface protective film 13 and a support sheet 10, is attached to the back surface 8b of a semiconductor wafer 8 having a circuit surface (Fig. 10(A')), the circuit surface protective tape 17 is peeled off (Fig. 10(B')), the film for forming a back surface protective film 13 is heat-cured or energy-ray-cured to form a back surface protective film 13' (Fig. 10(C')), the back surface protective film 13' is laser-marked from the side of the support sheet 10 (Fig. 10(D')), the semiconductor wafer 8 and the back surface protective film 13' are diced to form a semiconductor chip 7 with a back surface protective film (Fig. 10(E') and Fig. 10(F')), and the semiconductor chip 7 with a back surface protective film is picked up from the support sheet 10 (Fig. 10(G')). In this case as well, the order of the curing step and the laser marking step is arbitrary.

Japanese Patent No. 4271597 Japanese Patent No. 5363662

As described above, the first lamination step of laminating the film 13 for forming a back surface protective film on the back surface 8b of the semiconductor wafer 8 in Fig. 9(A) and the second lamination step of laminating the support sheet 10 on the back surface protective film 13' in Fig. 9(D) have conventionally been performed in separate devices. The laminate obtained in the first lamination step is stored in a cassette and transported manually to an apparatus for performing the second step, and this manual transport reduces the production efficiency of semiconductor chips with a back surface protective film.
Furthermore, there is a risk that the laminate obtained in the first lamination step may be contaminated or damaged while being contained in a cassette and transported.

In addition, in the conventional method for manufacturing semiconductor chips with a protective film shown in Figure 10, a composite sheet for forming a protective film 1 in which a film for forming a back surface protective film 13 and a support sheet 10 are integrated is used, so the process of attaching the film for forming a back surface protective film 13 to the workpiece to be protected by the film for forming a back surface protective film 13 (i.e., semiconductor wafer 8) and the process of attaching the support sheet 10 can be combined into a single process. However, when a composite sheet for forming a protective film 1 is used, the characteristics of the film for forming a back surface protective film 13 and the characteristics of the support sheet 10 must be combined together, and many types of composite sheets for forming a protective film 1 must be prepared in order to manufacture semiconductor chips with a protective film that meets the purpose.

In addition, the composite sheet 1 for forming a protective film can usually be manufactured by laminating the film 13 for forming a back surface protective film, which has been cut to a predetermined size, onto the support sheet 10, cutting the laminate to the size of a dicing tool, and removing unnecessary parts. Unlike the method of FIG. 9, in which the film 13 for forming a back surface protective film and the support sheet 10 are sequentially laminated onto the hard semiconductor wafer 8, the composite sheet 1 for forming a protective film is manufactured by laminating the film 13 for forming a back surface protective film and the support sheet 10, which are both soft, and thus the manufacturing process is difficult and the yield is poor, resulting in high manufacturing costs.

The present invention has been made in consideration of the above circumstances, and has an objective of providing a method for manufacturing a third laminate that can efficiently and at low cost produce a third laminate in which a workpiece such as a semiconductor wafer, a film for forming a back surface protective film, and a support sheet are stacked in this order.

The present invention provides a method for manufacturing a third laminate as follows:

[1] A method for producing a third laminate in which a workpiece, a film for forming a back surface protection film, and a support sheet are laminated in this order,
One surface of the workpiece is a circuit surface, and the other surface is a back surface,
A first lamination step of attaching the film for forming a back surface protection film to the back surface side of the workpiece;
A second lamination step of attaching the support sheet to the film for forming a back surface protection film,
Between the first lamination step and the second lamination step, a second laminate in which the film for forming a back surface protection film is laminated on the work is transported one by one;
A method for producing a third laminate, in which the steps from the first lamination step to the second lamination step are performed by connecting an apparatus for applying a film for forming a back surface protection film and an apparatus for applying a support sheet, or by performing these steps within the same apparatus.
[2] A method for producing a third laminate in which a workpiece, a film for forming a back surface protection film, and a support sheet are laminated in this order,
One surface of the workpiece is a circuit surface, and the other surface is a back surface,
A first lamination step of attaching the film for forming a back surface protection film to the back surface side of the workpiece;
A second lamination step of attaching the support sheet to the film for forming a back surface protection film,
A conveying distance of the work from a bonding start point of the first lamination process to a bonding completion point of the second lamination process is 7000 mm or less;
A method for producing a third laminate, in which the steps from the first lamination step to the second lamination step are performed by connecting an apparatus for applying a film for forming a back surface protection film and an apparatus for applying a support sheet, or by performing these steps within the same apparatus.
[3] A method for producing a third laminate in which a workpiece, a film for forming a back surface protection film, and a support sheet are laminated in this order,
One surface of the workpiece is a circuit surface, and the other surface is a back surface,
A first lamination step of attaching the film for forming a back surface protection film to the back surface side of the workpiece;
A second lamination step of attaching the support sheet to the film for forming a back surface protection film,
The conveying time of the work from the start of attachment in the first lamination process to the completion of attachment in the second lamination process is 400 s or less;
A method for producing a third laminate, in which the steps from the first lamination step to the second lamination step are performed by connecting an apparatus for applying a film for forming a back surface protection film and an apparatus for applying a support sheet, or by performing these steps within the same apparatus.
[4] The method for producing a third laminate described in [3], wherein a transport time of the workpiece from the start of attachment in the first lamination process to the completion of attachment in the second lamination process is 150 seconds or less.

According to the present invention, a method for manufacturing a third laminate is provided that can efficiently and at low cost produce a third laminate in which a workpiece such as a semiconductor wafer, a film for forming a back surface protective film, and a support sheet are stacked in this order.

FIG. 4 is a schematic cross-sectional view showing an example of an embodiment of a method for producing a third laminate. FIG. 2 is a schematic cross-sectional view showing an example of a film for forming a back surface protection film. FIG. 4 is a schematic cross-sectional view showing another embodiment of the method for producing a third laminate. FIG. 11 is a schematic cross-sectional view showing an example of an embodiment of a method for producing a fourth laminate. FIG. 11 is a schematic cross-sectional view showing another embodiment of the method for producing the fourth laminate. 1A to 1C are schematic cross-sectional views showing an example of an embodiment of a method for manufacturing a semiconductor device with a back surface protective film. 10 is a schematic cross-sectional view showing another embodiment of the method for manufacturing a semiconductor device with a back surface protective film. FIG. 10 is a schematic cross-sectional view showing another embodiment of the method for manufacturing a semiconductor device with a back surface protective film. FIG. FIG. 1 is a schematic cross-sectional view showing an example of a conventional method for manufacturing a semiconductor chip with a back surface protective film. FIG. 11 is a schematic cross-sectional view showing another example of a conventional method for manufacturing a semiconductor chip with a back surface protective film. FIG. 1 is a schematic cross-sectional view showing an example of a support sheet 10 in which a pressure-sensitive adhesive layer 12 is provided on a substrate 11.

The manufacturing method of the third laminate, which is an embodiment of the present invention, is described in detail below. Note that the drawings used in the following description may show characteristic parts in an enlarged scale for the sake of convenience in order to make the characteristics easier to understand, and the dimensional ratios of each component may not necessarily be the same as in reality.

<<Method of manufacturing third laminate>>
1 is a schematic cross-sectional view showing an example of an embodiment of the method for producing a third laminate. The method for producing the third laminate of this embodiment is a method for producing a third laminate 19 in which a work 14, a film 13 for forming a back surface protective film, and a support sheet 10 are laminated in this order, and includes a first lamination step (FIG. 1(b)) of attaching the film 13 for forming a back surface protective film to the back surface 14b side of the work 14, and a second lamination step (FIG. 1(d)) of attaching the support sheet 10 to the film 13 for forming a back surface protective film, in this order (FIGS. 1(a) to 1(e)).

In this embodiment, the steps from the first lamination step to the second lamination step (Figures 1(b) to (d)) are performed by connecting an apparatus for attaching a film for forming a back surface protective film and an apparatus for attaching a support sheet, or are performed within the same apparatus.
Therefore, in this embodiment, the second laminate in which the back surface protective film forming film 13 is laminated on the work 14 can be transported one by one to the second lamination step shown in FIG. 1(d) without being stored in a cassette between the first lamination step and the second lamination step. By performing the steps in the same device, the device space can be further reduced. By connecting the device for attaching the back surface protective film forming film and the device for attaching the support sheet, it is possible to respond by modifying the conventional device without having to design it from scratch, and the initial cost can be reduced. And, since the second laminate is not stored in a cassette and transported outside the device, the production efficiency is improved and contamination and damage of the second laminate can be suppressed.
Connecting an apparatus for applying a film for forming a back surface protective film and an apparatus for applying a support sheet means performing a step of connecting an apparatus for applying a film for forming a back surface protective film and an apparatus for applying a support sheet, and a step of performing the first lamination step to the second lamination step, or performing the first lamination step to the second lamination step using an apparatus in which an apparatus for applying a film for forming a back surface protective film and an apparatus for applying a support sheet are connected.

The back surface protective film forming film 13 used in the first lamination step may be processed to the shape of the work in advance, or may be processed in the same device immediately before the first lamination step. If the size of the work is constant on the production line used, the former, which allows processing in advance, is more efficient, while if the size of the work may change, the latter has a cost advantage in that no back surface protective film is wasted.

In another embodiment, the conveying distance of the work 14 from the start point of the attachment in the first lamination process to the end point of the attachment in the second lamination process can be designed to be 7000 mm or less, thereby reducing the space required for the device. The conveying distance of the work 14 from the start point of the attachment in the first lamination process to the end point of the attachment in the second lamination process can be 6500 mm or less, 6000 mm or less, 4500 mm or less, or 3000 mm or less.
In addition, the transport distance of the workpiece 14 from the start point of the attachment in the first lamination process to the end point of the attachment in the second lamination process can be 200 to 7000 mm or less, or 200 to 6000 mm, or 200 to 4500 mm, or 200 to 3000 mm.
In this specification, the transport distance of the work 14 from the start point of attachment in the first lamination process to the completion point of attachment in the second lamination process means the distance that the work 14 actually moves from the attachment point in the first lamination process to the completion point of attachment in the second lamination process.

In still another embodiment, the transport time of the work 14 from the start of attachment in the first lamination process to the completion of attachment in the second lamination process can be set to 400 seconds or less, or can be set to 150 seconds or less, thereby shortening the process time. The transport time of the work 14 from the start of attachment in the first lamination process to the completion of attachment in the second lamination process can be set to 130 seconds or less, 110 seconds or less, 90 seconds or less, or 70 seconds or less.
The transport time of the workpiece 14 from the start of attachment in the first lamination process to the completion of attachment in the second lamination process can be 15 to 400 s, 15 to 150 s, 15 to 130 s, 15 to 110 s, 15 to 90 s, or 15 to 70 s.

The transport time of the workpiece 14 from the start of attachment in the first lamination process to the completion of attachment in the second lamination process can be broadly divided into three parts: the time required for the first lamination process, the transport time from the location where the first lamination process was performed to the location where the second lamination process is performed, and the time required for the second lamination process.

The time required for the first lamination step can be 40 seconds or less, or 15 seconds or less, thereby shortening the process time. The time required for the first lamination step can be 10 seconds or less, or 8 seconds or less.
The time required for the first lamination step may be set to 3 to 40 seconds, 3 to 15 seconds, 3 to 10 seconds, or 3 to 8 seconds.

The transport time from the location where the first lamination step is performed to the location where the second lamination step is performed can be 200 seconds or less, or 75 seconds or less, thereby shortening the process time. The transport time from the location where the first lamination step is performed to the location where the second lamination step is performed can be 60 seconds or less, or 37 seconds or less.
In addition, the transport time from the location where the first lamination step is performed to the location where the second lamination step is performed can be 3 to 200 s, 3 to 75 s, 3 to 60 s, or 3 to 37 s.

The time required for the second lamination step can be 160 seconds or less, or 60 seconds or less, thereby shortening the process time. The time required for the second lamination step can be 40 seconds or less, or 25 seconds or less.
The time required for the second lamination step may be 3 to 160 seconds, 3 to 60 seconds, 3 to 40 seconds, or 3 to 25 seconds.

The transport distance of the work from the start of attachment of the first lamination process of this embodiment shown in FIG. 1(b) to the end of attachment of the second lamination process shown in FIG. 1(d) can be 7000 mm or less, 6500 mm or less, 6000 mm or less, 4500 mm or less, or 3000 mm or less. The transport time of the work from the start of attachment of the first lamination process of this embodiment shown in FIG. 1(b) to the end of attachment of the second lamination process shown in FIG. 1(d) can be 400 s or less, 150 s or less, 130 s or less, 110 s or less, 90 s or less, or 70 s or less.

The method for producing the third laminate of this embodiment can be carried out by connecting an apparatus for attaching the film for forming a rear surface protection film and an apparatus for attaching the support sheet, or can be carried out in the same apparatus.
The same apparatus may be, for example, an apparatus equipped with a back surface protective film forming film application table, a support sheet application table, and a transport arm.
Specifically, the work 14 put into the above-mentioned device is transported by a transport arm to a back surface protective film forming film attaching table, where the work 14 is placed with the back surface 14b facing up. At the back surface protective film forming film attaching table, a back surface protective film forming film 13 processed to a size matching the work 14 beforehand outside the device or immediately before inside the device is attached to the back surface 14b side of the work 14 to form a second laminate. The second laminate is transported by a transport arm to the support sheet attaching table, where the back surface protective film forming film side is placed with the back surface protective film forming film facing up. At the support sheet attaching table, a support tape 10 is attached to the back surface protective film forming film 13 of the second laminate to form a third laminate.

The speed at which the protective film-forming film 13 is attached to the back side of the workpiece 14 in the first lamination step, and the speed at which the support sheet 10 is attached to the protective film-forming film 13 in the second lamination step, can be 100 mm/sec or less, 80 mm/sec or less, 60 mm/sec or less, or 40 mm/sec or less. By setting the attaching speed in the first lamination step and the attaching speed in the second lamination step to be equal to or less than the upper limit, the adhesion between the workpiece 14 and the protective film-forming film 13 and the adhesion between the protective film-forming film 13 and the support sheet 10 can be made good.
The attaching speed in the first lamination step and the attaching speed in the second lamination step can be 2 mm/sec or more, 5 mm/sec or more, or 10 mm/sec or more. By making the attaching speed in the first lamination step and the attaching speed in the second lamination step equal to or more than the lower limit, the production efficiency of the third laminate 19 can be improved, and the transport time of the work 14 from the start of attaching in the first lamination step to the completion of attaching in the second lamination step can be set to 400 s or less.
The laminating speed in the first lamination step and the laminating speed in the second lamination step can be 2 to 100 mm/sec, 2 to 80 mm/sec, 5 to 60 mm/sec, or 10 to 40 mm/sec.

The device preferably has 1 to 5 film application tables for forming a back surface protective film, and more preferably has 1 to 3. If the number of film application tables for forming a back surface protective film in the device is equal to or greater than the lower limit of the range, production efficiency is improved, and if it is equal to or less than the upper limit, the space required for the device can be reduced.

The device preferably has 1 to 5 support sheet application tables, and more preferably has 1 to 3. If the number of support sheet application tables in the device is equal to or greater than the lower limit of the range, production efficiency will increase, and if it is equal to or less than the upper limit, the space required for the device can be reduced.

It is preferable that the device is provided with a transport arm for each transport path. If the ratio of the number of transport arms to the total number of tables is 1 or more, production efficiency can be improved. Furthermore, when two or more tables are provided, if the ratio of the number of transport arms to the total number of tables is greater than 0 and less than 1 (for example, a total of 1 transport arm for two tables), the space required for the device can be reduced.

A specific example of connecting an apparatus for applying a film for forming a back surface protective film and an apparatus for applying a support sheet is to connect an apparatus having a mechanism for applying a film for forming a back surface protective film to an apparatus having a mechanism for applying a support sheet, and transport the second laminate in which the film for forming a back surface protective film 13 is applied to the work 14 one by one using a transport arm between each mechanism.

In this embodiment, a semiconductor wafer is used as the workpiece 14 shown in FIG. 1(a). One surface of the semiconductor wafer is the circuit surface 14a, on which bumps are formed. In addition, in order to prevent the circuit surface 14a and bumps of the semiconductor wafer from being crushed during back grinding of the semiconductor wafer, or to prevent dimples or cracks from occurring on the back surface of the wafer, the circuit surface 14a and bumps of the semiconductor wafer may be protected by a circuit surface protection tape 17. The circuit surface protection tape 17 is a back surface grinding tape, and the back surface of the semiconductor wafer that is the workpiece 14 (i.e., the back surface 14b of the workpiece) may be the ground surface.

The work 14 is not limited as long as it has a circuit surface 14a on one side and the other side can be considered as a back surface. Examples of the work 14 include a semiconductor wafer having a circuit surface on one side, and a semiconductor device panel consisting of an assembly of terminal-equipped semiconductor devices in which individual electronic components are encapsulated with sealing resin and one side has a terminal formation surface (in other words, a circuit surface) of the terminal-equipped semiconductor device.

As the circuit surface protection tape 17, for example, the surface protection sheet disclosed in JP 2016-192488 A and JP 2009-141265 A can be used. The circuit surface protection tape 17 has an adhesive layer having moderate removability. The adhesive layer may be formed from a general-purpose weak adhesive such as a rubber-based, acrylic resin, silicone resin, urethane resin, or vinyl ether resin. The adhesive layer may also be an energy ray curable adhesive that is cured by irradiation with energy rays and becomes removably. The circuit surface protection tape 17 is in the form of a double-sided tape, and the outer side of the circuit surface protection tape 17 may be fixed to a hard support, or the work 14 may be fixed to the hard support.

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

In the first lamination step of this embodiment shown in FIG. 1(b), the back surface protective film forming film 13 can be used as the first laminate 5 shown in FIG. 2. The first laminate 5 shown in FIG. 2 has a first release film 151 on one side of the back surface protective film forming film 13, and a second release film 152 on the other side. After peeling off the first release film 151, in the first lamination step, the exposed surface 13a of the back surface protective film forming film 13 from which the release film has been peeled off is attached to the back surface 14b of the workpiece 14 (FIG. 1(b)). The back surface protective film forming film 13 at this time may be one that has been processed in advance to match the shape of the workpiece 14, or may be processed in the device immediately beforehand and used. Next, it is preferable to peel off the second release film 152 to form a second laminate (FIG. 1(c)).

The film for forming a back surface protective film shown in FIG. 2 is formed, for example, by applying a protective film forming composition containing a solvent onto the release surface of a second release film 152 having a thickness of 10 to 100 μm using a knife coater, and then drying in an oven at 120° C. for 2 minutes to form a film for forming a back surface protective film. Next, the release surface of a first release film 151 having a thickness of 10 to 100 μm is overlaid on the film for forming a back surface protective film, and the two are bonded together to obtain a first laminate 5 consisting of the first release film 151, the film for forming a back surface protective film (film for forming a back surface protective film 13 in FIG. 2) (thickness: 3 to 50 μm), and the second release film 152. Such a first laminate 5 is suitable for storage, for example, in a roll form.

In the second lamination step shown in FIG. 1(d), a support sheet 10 is laminated on the film 13 for forming a back surface protective film laminated on the back surface 14b of the workpiece 14. The support sheet 10 is, for example, a circular polyethylene terephthalate film having a thickness of 80 μm and a diameter of 270 mm, and may have a jig adhesive layer 16 on the outer periphery. In this embodiment, the workpiece 14 may be fixed to a fixing jig 18 together with the film 13 for forming a back surface protective film. Then, the support sheet 10 may be laminated on the film 13 for forming a back surface protective film, and may be fixed to the fixing jig 18 via the jig adhesive layer 16 (FIG. 1(e)).

(Protective film forming composition)
The protective film-forming composition for forming a back surface protective film-forming film preferably contains a binder polymer component and a curable component.

(Binder Polymer Component)
A binder polymer component is used to impart sufficient adhesiveness and film-forming properties (sheet-forming properties) to the film for forming a back surface protection film. As the binder polymer component, a conventionally known acrylic resin, polyester resin, urethane resin, acrylic urethane resin, silicone resin, rubber-based polymer, etc. can be used.

The weight average molecular weight (Mw) of the binder polymer component is preferably from 10,000 to 2,000,000, and more preferably from 100,000 to 1,200,000. If the weight average molecular weight of the binder polymer component is too low, the adhesive strength between the film for forming a back surface protective film and the support sheet increases, which may cause transfer failure of the film for forming a back surface protective film, whereas if it is too high, the adhesiveness of the film for forming a back surface protective film decreases, which may make it impossible to transfer to a chip or the like, or the back surface protective film may peel off from the chip or the like after transfer.
That is, when Mw is equal to or greater than the lower limit of the above range, the adhesive strength between the film for forming a back surface protection film and the support sheet does not become too high, and transfer defects of the film for forming a back surface protection film can be suppressed. When Mw is equal to or less than the upper limit of the above range, a decrease in the adhesiveness of the film for forming a back surface protection film is suppressed, and defects such as an inability to transfer to a chip or the like or peeling of the back surface protection film from the chip after transfer are suppressed.
In the present embodiment, the weight average molecular weight (Mw) is a polystyrene-equivalent value measured by gel permeation chromatography (GPC) unless otherwise specified.

As the binder polymer component, an acrylic resin is preferably used. The glass transition temperature (Tg) of the acrylic resin is preferably in the range of −60 to 50° C., more preferably −50 to 40° C., and particularly preferably −40 to 30° C. If the glass transition temperature of the acrylic resin is too low, the peeling force between the film for forming a back surface protection film and the support sheet increases, which may cause transfer failure of the film for forming a back surface protection film, and if the glass transition temperature is too high, the adhesiveness of the film for forming a back surface protection film decreases, making it impossible to transfer to a chip or the like, or the back surface protection film may peel off from the chip or the like after transfer.
That is, when Tg is equal to or greater than the lower limit of the above range, the peeling force between the film for forming a back surface protection film and the support sheet is not too large, and transfer defects of the film for forming a back surface protection film can be suppressed. When Tg is equal to or less than the upper limit of the above range, the decrease in adhesion of the film for forming a back surface protection film is suppressed, and defects such as failure to transfer to a chip or peeling of the back surface protection film from the chip after transfer are suppressed.
In this specification, the term "glass transition temperature" refers to the temperature at the inflection point of a DSC curve obtained by measuring a DSC curve of a sample using a differential scanning calorimeter.

Examples of monomers constituting the acrylic resin include (meth)acrylic acid ester monomers or derivatives thereof. For example, alkyl (meth)acrylates having an alkyl group with 1 to 18 carbon atoms, specifically methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc., can be mentioned. In addition, (meth)acrylates having a cyclic skeleton, specifically cyclohexyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, imide (meth)acrylate, etc. can be mentioned. Furthermore, examples of monomers having functional groups include hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, etc. having a hydroxyl group; and glycidyl (meth)acrylate, etc. having an epoxy group. As the acrylic resin, an acrylic resin containing a monomer having a hydroxyl group is preferable because it has good compatibility with the curable component described later. In addition, the acrylic resin may be copolymerized with acrylic acid, methacrylic acid, itaconic acid, vinyl acetate, acrylonitrile, styrene, etc.

In this specification, "(meth)acrylic acid" is a concept that includes both "acrylic acid" and "methacrylic acid." The same applies to terms similar to (meth)acrylic acid. For example, "(meth)acrylate" is a concept that includes both "acrylate" and "methacrylate," and "(meth)acryloyl group" is a concept that includes both "acryloyl group" and "methacryloyl group."

Furthermore, a thermoplastic resin may be blended as a binder polymer component to maintain the flexibility of the protective film after curing. Such a thermoplastic resin preferably has a weight average molecular weight of 1,000 to 100,000, more preferably 3,000 to 80,000. The glass transition temperature of the thermoplastic resin is preferably -30 to 120°C, more preferably -20 to 120°C. Examples of the thermoplastic resin include polyester resin, urethane resin, phenoxy resin, polybutene, polybutadiene, polystyrene, etc. These thermoplastic resins can be used alone or in combination of two or more. By containing the above-mentioned thermoplastic resin, the film for forming a back surface protective film can follow the transfer surface of the film for forming a back surface protective film, thereby suppressing the occurrence of voids, etc.

(curable component)
The curable component may be a thermosetting component and/or an energy ray curable component.

As the thermosetting component, a thermosetting resin and a thermosetting agent are used. As the thermosetting resin, for example, an epoxy resin is preferable.

As the epoxy resin, a conventionally known epoxy resin can be used. Specific examples of the epoxy resin include 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, and other epoxy compounds having two or more functional groups in the molecule. These can be used alone or in combination of two or more types.

The film for forming a back surface protection film contains a thermosetting resin in an amount of preferably 1 to 1000 parts by mass, more preferably 10 to 500 parts by mass, and particularly preferably 20 to 200 parts by mass, per 100 parts by mass of the binder polymer component. If the content of the thermosetting resin is less than 1 part by mass, sufficient adhesion may not be obtained, whereas if it exceeds 1000 parts by mass, the peel strength between the film for forming a back surface protection film and the pressure-sensitive adhesive sheet or base film increases, and transfer failure of the film for forming a back surface protection film may occur.
That is, when the content of the thermosetting resin is equal to or more than the lower limit of the above range, sufficient adhesion is obtained. When the content of the thermosetting resin is equal to or less than the upper limit of the above range, the peel strength between the film for forming a back surface protection film and the pressure-sensitive adhesive sheet or base film is not too high, and transfer defects of the film for forming a back surface protection film are suppressed.

The thermosetting agent functions as a curing agent for thermosetting resins, particularly epoxy resins. Preferred thermosetting agents include compounds having two or more functional groups in one molecule that can react with epoxy groups. Such functional groups include phenolic hydroxyl groups, alcoholic hydroxyl groups, amino groups, carboxyl groups, and acid anhydrides. Of these, phenolic hydroxyl groups, amino groups, and acid anhydrides are preferred, and phenolic hydroxyl groups and amino groups are more preferred.

Specific examples of phenol-based hardeners include polyfunctional phenol resins, biphenols, novolac-type phenol resins, dicyclopentadiene-type phenol resins, xylok-type phenol resins, and aralkyl phenol resins. Specific examples of amine-based hardeners include DICY (dicyandiamide). These can be used alone or in combination of two or more.

The content of the heat curing agent is preferably 0.1 to 500 parts by mass, and more preferably 1 to 200 parts by mass, relative to 100 parts by mass of the thermosetting resin. If the content of the heat curing agent is small, the curing may be insufficient and adhesiveness may not be obtained, whereas if the content is excessive, the moisture absorption rate of the film for forming a back surface protection film may increase, thereby reducing the reliability of the semiconductor device.
That is, when the content of the heat curing agent is equal to or more than the lower limit of the above range, insufficient curing is unlikely to occur, and adhesiveness is easily obtained. When the content of the heat curing agent is equal to or less than the upper limit of the above range, the moisture absorption rate of the film for forming a back surface protection film is not increased, and the reliability of the semiconductor device is not likely to decrease.

As the energy ray curable component, a low molecular weight compound (energy ray polymerizable compound) that contains an energy ray polymerizable group and polymerizes and hardens when irradiated with energy rays such as ultraviolet rays and electron beams can be used. Specific examples of such energy ray curable components include trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, and acrylate-based compounds such as 1,4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, oligoester acrylate, urethane acrylate-based oligomer, epoxy modified acrylate, polyether acrylate, and itaconic acid oligomer. Such compounds have at least one polymerizable double bond in the molecule and usually have a weight average molecular weight of 100 to 30,000, preferably about 300 to 10,000. The amount of the energy ray polymerizable compound to be blended is preferably 1 to 1,500 parts by mass, more preferably 10 to 500 parts by mass, and particularly preferably 20 to 200 parts by mass, based on 100 parts by mass of the binder polymer component.

In addition, an energy beam curable polymer in which an energy beam polymerizable group is bonded to the main chain or side chain of a binder polymer component may be used as the energy beam curable component. Such an energy beam curable polymer combines the function of a binder polymer component and the function of a curable component.

The main skeleton of the energy beam-curable polymer is not particularly limited and may be an acrylic resin, which is commonly used as a binder polymer component, or a polyester resin, polyether resin, etc., but it is particularly preferable to use an acrylic resin as the main skeleton because it is easy to synthesize and control the physical properties.

The energy ray-polymerizable group bonded to the main chain or side chain of the energy ray-curable polymer is, for example, a group containing an energy ray-polymerizable carbon-carbon double bond, and specific examples thereof include a (meth)acryloyl group. The energy ray-polymerizable group may be bonded to the energy ray-curable polymer via an alkylene group, an alkyleneoxy group, or a polyalkyleneoxy group.

The weight average molecular weight (Mw) of the energy ray curable polymer to which the energy ray polymerizable group is bonded is preferably 10,000 to 2,000,000, and more preferably 100,000 to 1,500,000. The glass transition temperature (Tg) of the energy ray curable polymer is preferably in the range of -60 to 50°C, more preferably -50 to 40°C, and particularly preferably -40 to 30°C.

Energy beam curable polymers are obtained by reacting an acrylic resin containing functional groups such as hydroxyl groups, carboxyl groups, amino groups, substituted amino groups, and epoxy groups with a polymerizable group-containing compound having a substituent that reacts with the functional groups and 1 to 5 energy beam polymerizable carbon-carbon double bonds per molecule. Examples of the substituent that reacts with the functional groups include isocyanate groups, glycidyl groups, and carboxyl groups.

Examples of polymerizable group-containing compounds include (meth)acryloyloxyethyl isocyanate, meta-isopropenyl-α,α-dimethylbenzyl isocyanate, (meth)acryloyl isocyanate, allyl isocyanate, glycidyl (meth)acrylate; (meth)acrylic acid, etc.

The acrylic resin is preferably a copolymer consisting of a (meth)acrylic monomer or its derivative having a functional group such as a hydroxyl group, a carboxyl group, an amino group, a substituted amino group, or an epoxy group, and another (meth)acrylic acid ester monomer or its derivative that is copolymerizable therewith.

Examples of (meth)acrylic monomers or derivatives thereof having functional groups such as hydroxyl groups, carboxyl groups, amino groups, substituted amino groups, and epoxy groups include 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate having hydroxyl groups; acrylic acid, methacrylic acid, and itaconic acid having carboxyl groups; and glycidyl methacrylate and glycidyl acrylate having epoxy groups.

Other (meth)acrylic acid ester monomers or derivatives thereof that can be copolymerized with the above monomers include, for example, alkyl (meth)acrylates in which the alkyl group has 1 to 18 carbon atoms, specifically methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc.; (meth)acrylates having a cyclic skeleton, specifically cyclohexyl (meth)acrylate, benzyl (meth)acrylate, isobornyl acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, imide acrylate, etc. In addition, the above acrylic resins may be copolymerized with vinyl acetate, acrylonitrile, styrene, etc.

Even when an energy beam curable polymer is used, the above-mentioned energy beam polymerizable compound may be used in combination, or a binder polymer component may be used in combination. The relationship of the blending amounts of these three components in the film for forming a back surface protective film in the present invention is such that the energy beam polymerizable compound is preferably contained in an amount of 1 to 1500 parts by mass, more preferably 10 to 500 parts by mass, and particularly preferably 20 to 200 parts by mass, per 100 parts by mass of the sum of the masses of the energy beam curable polymer and the binder polymer component.

By imparting energy ray curing properties to the film for forming a back surface protective film, the film for forming a back surface protective film can be cured easily and in a short time, improving the production efficiency of chips with a protective film. Conventionally, protective films for chips have generally been formed from thermosetting resins such as epoxy resins, but the curing temperature of thermosetting resins exceeds 200°C and the curing time requires about two hours, which has been an obstacle to improving production efficiency. However, energy ray curable films for forming a back surface protective film can be cured in a short time by irradiation with energy rays, making it possible to easily form a protective film and contributing to improving production efficiency.

The film for forming a back surface protective film may contain the following components in addition to the above binder polymer component and curable component.

(Coloring Agent)
The film for forming a back surface protective film preferably contains a colorant. By blending a colorant into the film for forming a back surface protective film, when the semiconductor device is incorporated into an apparatus, infrared rays and the like generated from the surrounding device can be shielded, and malfunction of the semiconductor device due to them can be prevented. In addition, the visibility of characters when a product number or the like is printed on the protective film obtained by curing the film for forming a back surface protective film is improved. That is, in a semiconductor device or semiconductor chip on which a protective film is formed, a product number or the like is usually printed on the surface of the protective film by a laser marking method (a method of scraping off the surface of the protective film with laser light and printing), but by containing a colorant in the protective film, a sufficient contrast difference is obtained between the part of the protective film scraped off by the laser light and the part that is not, and visibility is improved. As the colorant, organic or inorganic pigments and dyes are used. Among these, black pigments are preferred from the viewpoint of electromagnetic wave and infrared ray shielding properties. As the black pigment, carbon black, iron oxide, manganese dioxide, aniline black, activated carbon, etc. are used, but are not limited to these. From the viewpoint of improving the reliability of the semiconductor device, carbon black is particularly preferred. The colorant may be used alone or in combination of two or more. The high curability of the film for forming a back surface protection film in the present invention is particularly preferably exhibited when a colorant that reduces the transmittance of both visible light and/or infrared light and ultraviolet light is used to reduce the transmittance of ultraviolet light. The colorant that reduces the transmittance of both visible light and/or infrared light and ultraviolet light is not particularly limited as long as it has absorptivity or reflectivity in the wavelength range of both visible light and/or infrared light and ultraviolet light, in addition to the above black pigment.

The amount of colorant is preferably 0.1 to 35 parts by weight, more preferably 0.5 to 25 parts by weight, and particularly preferably 1 to 15 parts by weight, per 100 parts by weight of the total solids constituting the film for forming a back surface protective film.

(Cure Accelerator)
The curing accelerator is used to adjust the curing speed of the film for forming a back surface protection film, and is preferably used particularly when an epoxy resin and a heat curing agent are used in combination in the curable component.

Preferred curing accelerators include tertiary amines such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol; imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole; organic phosphines such as tributylphosphine, diphenylphosphine, and triphenylphosphine; and tetraphenylboron salts such as tetraphenylphosphonium tetraphenylborate and triphenylphosphine tetraphenylborate. These can be used alone or in combination of two or more.

The curing accelerator is preferably contained in an amount of 0.01 to 10 parts by mass, more preferably 0.1 to 1 part by mass, per 100 parts by mass of the curable component. By containing the curing accelerator in the above range, the adhesive has excellent adhesive properties even when exposed to high temperatures and high humidity, and high reliability can be achieved even when exposed to severe reflow conditions. If the content of the curing accelerator is low, sufficient adhesive properties cannot be obtained due to insufficient curing, and if it is excessive, the curing accelerator, which has high polarity, migrates to the adhesive interface side in the film for forming a back surface protective film under high temperatures and high humidity, and segregates, thereby reducing the reliability of the semiconductor device.

(Coupling Agent)
The coupling agent may be used to improve the adhesion and adhesion of the film for forming a back surface protective film to the chip and/or the cohesion of the protective film. In addition, by using the coupling agent, the water resistance of the protective film obtained by curing the film for forming a back surface protective film can be improved without impairing the heat resistance of the protective film.

As a coupling agent, a compound having a group that reacts with a functional group of the binder polymer component, the curable component, etc. is preferably used. As a coupling agent, a silane coupling agent is preferable. Examples of such coupling agents include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-(methacryloxypropyl)trimethoxysilane, γ-aminopropyltrimethoxysilane, N-6-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-6-(aminoethyl)-γ-aminopropylmethyldiethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, bis(3-triethoxysilylpropyl)tetrasulfane, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, imidazolesilane, etc. These can be used alone or in combination of two or more.

The coupling agent is usually contained in an amount of 0.1 to 20 parts by mass, preferably 0.2 to 10 parts by mass, and more preferably 0.3 to 5 parts by mass, based on 100 parts by mass of the binder polymer component and the curable component in total. If the content of the coupling agent is less than 0.1 part by mass, the above effect may not be obtained, and if it exceeds 20 parts by mass, it may cause outgassing.
That is, when the content of the coupling agent is equal to or more than the lower limit of the above range, the effect of the coupling agent is obtained, and when it is equal to or less than the upper limit, outgassing is suppressed.

(Inorganic filler)
By incorporating an inorganic filler into the film for forming a back surface protection film, it becomes possible to adjust the thermal expansion coefficient of the cured protection film, and by optimizing the thermal expansion coefficient of the cured protection film relative to the semiconductor chip, it is possible to improve the reliability of the semiconductor device. It is also possible to reduce the moisture absorption rate of the cured protection film.

Preferred inorganic fillers include powders of silica, alumina, talc, calcium carbonate, titanium oxide, iron oxide, silicon carbide, boron nitride, etc., beads made by shaping these into spherical form, single crystal fibers, and glass fibers. Among these, silica filler and alumina filler are preferred. The above inorganic fillers can be used alone or in a mixture of two or more. The content of the inorganic filler can usually be adjusted within the range of 1 to 80 parts by mass per 100 parts by mass of the total solid content constituting the film for forming a back surface protective film.

(Photopolymerization initiator)
When the film for forming a back surface protection film contains an energy ray curable component as the curable component, the energy ray curable component is cured by irradiating it with energy rays such as ultraviolet rays when it is used. In this case, by including a photopolymerization initiator in the composition, the polymerization curing time and the amount of light irradiation can be reduced.

Specific examples of such photopolymerization initiators include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin methyl benzoate, benzoin dimethyl ketal, 2,4-diethylthioxanthone, α-hydroxycyclohexyl phenyl ketone, benzyl diphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, 1,2-diphenylmethane, 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and β-chloroanthraquinone. The photopolymerization initiators can be used alone or in combination of two or more.

The blending ratio of the photopolymerization initiator is preferably 0.1 to 10 parts by mass, and more preferably 1 to 5 parts by mass, per 100 parts by mass of the energy ray-curable component. If the blending ratio is less than 0.1 part by mass, satisfactory transferability may not be obtained due to insufficient photopolymerization, whereas if the blending ratio exceeds 10 parts by mass, residues that do not contribute to photopolymerization may be generated, resulting in insufficient curability of the film for forming a back surface protective film.
In other words, when the blending ratio of the photopolymerization initiator is equal to or higher than the lower limit of the above range, the photopolymerization proceeds sufficiently and satisfactory transferability is obtained, and when the blending ratio is equal to or lower than the upper limit, the generation of residues that do not contribute to photopolymerization is suppressed and the hardening property of the film for forming a back surface protection film is sufficient.

(Crosslinking Agent)
In order to adjust the initial adhesive strength and cohesive strength of the film for forming a back surface protection film, a crosslinking agent may be added, such as an organic polyvalent isocyanate compound or an organic polyvalent imine compound.

Examples of the organic polyisocyanate compounds include aromatic polyisocyanate compounds, aliphatic polyisocyanate compounds, alicyclic polyisocyanate compounds, and trimers of these organic polyisocyanate compounds, as well as isocyanate-terminated urethane prepolymers obtained by reacting these organic polyisocyanate compounds with polyol compounds.

Examples of organic polyisocyanate compounds 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, trimethylolpropane adduct tolylene diisocyanate, and lysine isocyanate.

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

The crosslinking agent is usually used in a ratio of 0.01 to 20 parts by mass, preferably 0.1 to 10 parts by mass, and more preferably 0.5 to 5 parts by mass, per 100 parts by mass of the combined amount of the binder polymer component and the energy beam curable polymer.

(General purpose additive)
In addition to the above, the back surface protective film may contain various additives as necessary, such as a leveling agent, a plasticizer, an antistatic agent, an antioxidant, an ion trapping agent, a gettering agent, and a chain transfer agent.

(solvent)
The protective film-forming composition preferably further contains a solvent. A protective film-forming composition containing a solvent has good handleability.
The solvent is not particularly limited, but preferred examples thereof 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 protective film-forming composition may contain only one type of solvent, or two or more types. When two or more types are contained, the combination and ratio of the solvents can be selected arbitrarily.

It is preferable that the solvent contained in the protective film-forming composition is methyl ethyl ketone or the like, since this allows the components contained in the protective film-forming composition to be mixed more uniformly.

The film for forming a back surface protective film obtained by applying and drying the protective film-forming composition composed of each of the above-mentioned components has adhesiveness and curability, and in an uncured state, it is easily adhered to a workpiece (such as a semiconductor wafer or chip) by pressing it. When pressing, the film for forming a back surface protective film may be heated. After curing, it can finally provide a protective film with high impact resistance, excellent adhesive strength, and can maintain sufficient protective function even under severe high temperature and high humidity conditions. The film for forming a back surface protective film may have a single layer structure, or may have a multilayer structure as long as it contains one or more layers containing the above-mentioned components.
The ratio of the contents of the components that do not vaporize at room temperature in the film for forming a back surface protective film is the same as the ratio of the contents of the components in the protective film-forming composition. In this specification, "room temperature" means a temperature that is not particularly cooled or heated, that is, an ordinary temperature, and examples of the temperature include a temperature of 15 to 25°C.

The protective film-forming composition may be applied by known methods, such as methods 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, Mayer bar coater, and kiss coater.

The drying conditions for the protective film-forming composition are not particularly limited, but if the protective film-forming composition contains a solvent as described below, it is preferable to heat-dry it. The protective film-forming composition containing a solvent is preferably dried, for example, at 70 to 130°C for 10 seconds to 5 minutes.

The thickness of the film for forming a back surface protection film is not particularly limited, but is preferably 3 to 300 μm, more preferably 5 to 250 μm, and particularly preferably 7 to 200 μm.
In this specification, "thickness" refers to a value expressed as the average of thicknesses measured with a contact thickness meter at five randomly selected points on a cross section of an object cut randomly in the thickness direction.

<Support sheet>
Examples of the support sheet 10 used in one embodiment of the present invention include a sheet constituted only of a substrate 11 and an adhesive sheet having an adhesive layer 12 on a substrate 11 .
The support sheet of the third laminate of one embodiment of the present invention serves as a release sheet for preventing the adhesion of dust and the like to the surface of the film for forming a back surface protective film, or a dicing sheet for protecting the surface of the film for forming a back surface protective film during a dicing process, etc.

The thickness of the support sheet is appropriately selected depending on the application, but from the viewpoint of providing sufficient flexibility and good adhesion to the silicon wafer, it is preferably 10 to 500 μm, more preferably 20 to 350 μm, and even more preferably 30 to 200 μm.
The thickness of the support sheet mentioned above includes not only the thickness of the base material constituting the support sheet, but also the thickness of the pressure-sensitive adhesive layer, if any, of the layer or film.

(Base material)
The substrate 11 constituting the support sheet 10 is preferably a resin film.
Examples of the resin film include polyethylene films such as low-density polyethylene (LDPE) films and linear low-density polyethylene (LLDPE) films, ethylene-propylene copolymer films, polypropylene films, polybutene films, polybutadiene films, polymethylpentene films, polyvinyl chloride films, vinyl chloride copolymer films, polyethylene terephthalate films, polyethylene naphthalate films, polybutylene terephthalate films, polyurethane films, ethylene-vinyl acetate copolymer films, ionomer resin films, ethylene-(meth)acrylic acid copolymer films, ethylene-(meth)acrylic acid ester copolymer films, polystyrene films, polycarbonate films, polyimide films, and fluororesin films.
The substrate used in one embodiment of the present invention may be a single layer film made of one type of resin film, or a laminate film made of two or more types of resin films laminated together.
In one embodiment of the present invention, a sheet in which the surface of a substrate such as the above-mentioned resin film has been subjected to a surface treatment may be used as the support sheet.

These resin films may be crosslinked films.
Furthermore, these resin films may be colored or printed.
Furthermore, the resin film may be a sheet made by extrusion molding of a thermoplastic resin, or may be a stretched film, or may be a sheet made by thinning and curing a curable resin by a specified means.

Among these resin films, a substrate containing a polypropylene film is preferred from the viewpoints that it has excellent heat resistance and appropriate flexibility, and therefore has expandability, and also easily maintains pick-up suitability.
The base material containing a polypropylene film may have a single-layer structure made of only a polypropylene film, or a multi-layer structure made of a polypropylene film and another resin film.
When the film for forming a back surface protection film is thermosetting, the resin film constituting the base material has heat resistance, so that damage to the base material due to heat can be suppressed and the occurrence of defects in the manufacturing process of the semiconductor device can be suppressed.

When a sheet consisting of only a substrate is used as the support sheet, the surface tension of the substrate's surface that comes into contact with the surface of the film for forming a back surface protective film is preferably 20 to 50 mN/m, more preferably 23 to 45 mN/m, and even more preferably 25 to 40 mN/m, from the viewpoint of adjusting the peel force within a certain range.

The thickness of the substrate constituting the support sheet is preferably 10 to 500 μm, more preferably 15 to 300 μm, and even more preferably 20 to 200 μm.

(Adhesive sheet)
An example of the pressure-sensitive adhesive sheet used as the support sheet 10 in one embodiment of the present invention is one having a pressure-sensitive adhesive layer 12 formed from a pressure-sensitive adhesive on a substrate 11 such as the above-mentioned resin film.
FIG. 11 is a schematic cross-sectional view showing an example of a support sheet 10 in which a pressure-sensitive adhesive layer 12 is provided on a substrate 11.
When the support sheet 10 includes the pressure-sensitive adhesive layer 12, the pressure-sensitive adhesive layer 12 of the support sheet 10 is laminated onto the film 13 for forming a back surface protection film in the second lamination step.

The adhesive that is the material for forming the adhesive layer can be an adhesive composition containing an adhesive resin, and the adhesive composition may further contain general-purpose additives such as the above-mentioned crosslinking agent and tackifier.
In terms of the structure of the adhesive resin, examples thereof include acrylic resin, urethane resin, phenoxy resin, silicone resin, saturated polyester resin, vinyl ether resin, etc., and acrylic resin is preferred. In terms of the function of the resin, examples thereof include energy ray curable adhesives, heat foaming adhesives, energy ray foaming adhesives, etc.
In one aspect of the present invention, from the viewpoint of adjusting the peel force within a certain range and from the viewpoint of achieving good pick-up properties, a pressure-sensitive adhesive sheet having an energy ray-curable pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive composition containing an energy ray-curable resin, or a pressure-sensitive adhesive sheet having a slightly adhesive layer is preferred.
The energy ray curable resin may be any resin having a polymerizable group such as a (meth)acryloyl group or a vinyl group, but is preferably an adhesive resin having a polymerizable group.

In the first lamination step, when the film for forming a back surface protective film is not attached to the entire surface of the workpiece such as a semiconductor wafer, the film for forming a back surface protective film floats, or the film for forming a back surface protective film wrinkles, the support sheet can also serve as a sheet for removing the film for forming a back surface protective film. Even if the film for forming a back surface protective film is not attached to the entire surface of the workpiece such as a semiconductor wafer, the support sheet can also serve as a sheet for removing the film for forming a back surface protective film. Even if the film for forming a back surface protective film is not attached to the entire surface of the workpiece such as a semiconductor wafer, the support sheet can be used to remove the film for forming a back surface protective film from the workpiece such as a semiconductor wafer, and the support sheet can be used to remove the film for forming a back surface protective film. In this case, when considering the production takt time, it is necessary to quickly remove the support sheet from the fixing jig (i.e., the ring frame), and it is preferable that the adhesive layer for the jig is energy ray curable. Furthermore, by using a support sheet having an energy ray-curable adhesive layer provided on a substrate, the support sheet can be fixed directly to a fixing jig such as a ring frame without using a jig adhesive layer, and by irradiating the support sheet with energy rays such as ultraviolet rays, the support sheet can be made to have excellent reworkability.

From the viewpoint of adjusting the peel strength within a certain range, a pressure-sensitive adhesive containing an acrylic resin is preferred.
As the acrylic resin, an acrylic polymer having a structural unit (x1) derived from an alkyl (meth)acrylate is preferable, and an acrylic copolymer having the structural unit (x1) and a structural unit (x2) derived from a functional group-containing monomer is more preferable.

The alkyl group of the alkyl (meth)acrylate preferably has 1 to 18 carbon atoms, more preferably 1 to 12 carbon atoms, and even more preferably 1 to 8 carbon atoms.
Examples of the alkyl (meth)acrylate include the same alkyl (meth)acrylates as those described in the binder polymer component section above.
The alkyl (meth)acrylates may be used alone or in combination of two or more kinds.
The content of the structural unit (x1) is usually 50 to 100 mass%, preferably 50 to 99.9 mass%, more preferably 60 to 99 mass%, and even more preferably 70 to 95 mass%, based on all structural units (100 mass%) of the acrylic polymer.

Examples of the functional group-containing monomer include a hydroxy group-containing monomer, a carboxy group-containing monomer, and an epoxy group-containing monomer. Specific examples of each monomer include the same monomers as those exemplified in the binder polymer component.
These may be used alone or in combination of two or more kinds.
The content of the structural unit (x2) is usually 0 to 40 mass%, preferably 0.1 to 40 mass%, more preferably 1 to 30 mass%, and even more preferably 5 to 20 mass%, based on all structural units (100 mass%) of the acrylic polymer.

The acrylic resin used in one embodiment of the present invention may be an energy ray-curable acrylic resin obtained by reacting an acrylic copolymer having the above structural units (x1) and (x2) with a compound having an energy ray-polymerizable group.
The compound having an energy ray-polymerizable group may be a compound having a polymerizable group such as a (meth)acryloyl group or a vinyl group.

When a pressure-sensitive adhesive containing an acrylic resin is used, it is preferable to contain a crosslinking agent together with the acrylic resin, from the viewpoint of adjusting the peel strength within a certain range.
Examples of the crosslinking agent include isocyanate-based crosslinking agents, imine-based crosslinking agents, epoxy-based crosslinking agents, oxazoline-based crosslinking agents, and carbodiimide-based crosslinking agents. From the viewpoint of adjusting the peel strength within a certain range, isocyanate-based crosslinking agents are preferred.
The content of the crosslinking agent is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, even more preferably 0.5 to 10 parts by mass, and still more preferably 1 to 8 parts by mass, relative to the total mass (100 parts by mass) of the acrylic resin contained in the pressure-sensitive adhesive.

The support sheet 10 may be made of one layer (single layer) or may be made of two or more layers. When the support sheet is made of multiple layers, the constituent materials and thicknesses of these multiple layers may be the same or different, and the combination of these multiple layers is not particularly limited as long as it does not impair the effects of the present invention.

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

The support sheet may be transparent or opaque, and may be colored depending on the purpose.
For example, when the film for forming the back surface protection film has energy ray curing properties, the support sheet is preferably one that transmits energy rays.
For example, in order to optically inspect the film for forming a back surface protection film through the support sheet, it is preferable that the support sheet is transparent.

In this embodiment, the circuit surface 14a of the workpiece 14 is protected by the circuit surface protection tape 17, and after the second lamination step, a peeling step can be included in which the circuit surface protection tape 17 is peeled off from the circuit surface 14a of the workpiece 14. In this embodiment, the circuit surface protection tape 17 has an energy ray curable adhesive layer on the side attached to the circuit surface 14a, which is cured by irradiation with energy rays and becomes removable. In the peeling step, the adhesive layer of the circuit surface protection tape 17 is irradiated with energy rays to harden the adhesive layer and make it removable, thereby making it easy to peel off the circuit surface protection tape 17 from the circuit surface 14a of the workpiece 14.

The manufacturing method of the third laminate of this embodiment may include a step of laser marking the film 13 for forming a back surface protective film by irradiating the film 13 for forming a back surface protective film with a laser from the side of the support sheet 10. In the manufacturing method of the third laminate of this embodiment, the support sheet 10 is laminated on the film 13 for forming a back surface protective film, so that when a laser is irradiated from the side of the support sheet 10 through the support sheet, laser marking can be performed on the surface of the film 13 for forming a back surface protective film that is in contact with the support sheet 10.

Figure 3 is a schematic cross-sectional view showing another embodiment of the method for manufacturing a third laminate. In the figures following Figure 3, 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 descriptions thereof are omitted.

In this embodiment, the work 14 is a semiconductor device panel consisting of an assembly of semiconductor devices in which at least one electronic component 62 is sealed with a sealing resin layer 64, arranged side by side in a plane. The manufacturing method of the third laminate of this embodiment is a manufacturing method of a third laminate 19 in which the semiconductor device panel as the work 14, the film 13 for forming a back surface protective film, and the support sheet 10 are laminated in this order, and one surface of the work 14 is the circuit surface 14a, and the other surface is the back surface 14b (FIG. 3(a')), and includes a first lamination step (FIG. 3(b')) of attaching the film 13 for forming a back surface protective film to the back surface 14b side of the work 14, and a second lamination step (FIG. 3(c')) of attaching the support sheet 10 to the film 13 for forming a back surface protective film, in this order (FIGS. 3(a')(d')).
In this embodiment, the steps from the first lamination step to the second lamination step (Figures 3(a') to (d')) are performed by connecting an apparatus for attaching a film for forming a back surface protection film and an apparatus for attaching a support sheet, or are performed within the same apparatus.
Therefore, in this embodiment, the second laminate in which the back surface protective film forming film 13 is laminated on the work 14 can be transported one by one to the second lamination step shown in FIG. 3(d') without being stored in a cassette between the first lamination step and the second lamination step. By performing the steps in the same device, the device space can be further reduced. By connecting the device for attaching the back surface protective film forming film and the device for attaching the support sheet, it is possible to respond by modifying the conventional device without having to design it from scratch, and the initial cost can be reduced. And, since the second laminate is not stored in a cassette and transported outside the device, the production efficiency is improved and contamination and damage of the second laminate can be suppressed.

The back surface protective film forming film 13 used in the first lamination step may be processed to the shape of the work in advance, or may be processed in the same device immediately before the first lamination step. If the size of the work is constant on the production line used, the former, which allows processing in advance, is more efficient, while if the size of the work may change, the latter has a cost advantage in that no back surface protective film is wasted.

In another embodiment, the transport distance of the work 14 from the start point of attachment in the first lamination process to the end point of attachment in the second lamination process can be designed to be 7000 mm or less, thereby reducing the equipment space. The transport distance of the work 14 from the start point of attachment in the first lamination process to the end point of attachment in the second lamination process can be 6500 mm or less, 6000 mm or less, 4500 mm or less, or 3000 mm or less.

In yet another embodiment, the transport time of the work 14 from the start of attachment in the first lamination process to the completion of attachment in the second lamination process can be set to 400 seconds or less, or can be set to 150 seconds or less, thereby shortening the process time. The transport time of the work 14 from the start of attachment in the first lamination process to the completion of attachment in the second lamination process can be set to 130 seconds or less, 110 seconds or less, 90 seconds or less, or 70 seconds or less.

When the transport time of the workpiece 14 from the start of attachment in the first lamination process to the completion of attachment in the second lamination process is broadly divided into three parts: the time required for the first lamination process, the transport time from the location where the first lamination process was performed to the location where the second lamination process is performed, and the time required for the second lamination process, the preferred ranges for each of these times are the same as those described in the manufacturing method of Figure 1.

The method for producing the third laminate of this embodiment can be carried out by connecting an apparatus for attaching the film for forming a rear surface protection film and an apparatus for attaching the support sheet, or can be carried out in the same apparatus.
As the same apparatus, it is preferable to use the apparatus explained in the manufacturing method of FIG.

In this embodiment, the semiconductor device panel may be formed with individual semiconductor devices arranged in a planar manner within a substantially circular area, or may be formed with individual semiconductor devices arranged in a planar manner within a substantially rectangular area.

In the present embodiment shown in Figure 3, as in the embodiment shown in Figure 1, a support sheet 10 is laminated on a film 13 for forming a back surface protective film, so that when a laser is irradiated from the side of the support sheet 10 through the support sheet, laser marking can be performed on the surface of the film 13 for forming a back surface protective film that is in contact with the support sheet 10.

<<Method for producing fourth laminate>>
The manufacturing method of the fourth laminate in this embodiment is a manufacturing method of a fourth laminate 19' in which a work 14, a back surface protective film 13', and a support sheet 10 are laminated in this order, and includes a curing step of curing the film 13 for forming a back surface protective film of the third laminate 19 manufactured by the manufacturing method of the third laminate to form a back surface protective film 13'.

Figure 4 is a schematic cross-sectional view showing an example of an embodiment of the manufacturing method of the fourth laminate. The manufacturing method of the fourth laminate of this embodiment includes a peeling step (Figure 4(e)) of peeling the circuit surface protection tape 17 from the circuit surface 14a of the workpiece 14 after the second lamination step, a step (Figure 4(f)) of irradiating the back surface protection film forming film 13 with a laser from the support sheet 10 side to perform laser marking, and a curing step (Figure 4(g)) of curing the back surface protection film forming film 13 to form the back surface protection film 13'. In this embodiment, a thermosetting back surface protection film forming film is used, and in the curing step of this embodiment, the film is thermally cured under conditions of 130 ° C. and 2 h.

The curing conditions when a thermosetting film for forming a back surface protective film is heat-treated to heat-cure it to form a back surface protective film are not particularly limited as long as the degree of curing is such that the back surface protective film can fully perform its function, and may be selected appropriately depending on the type of thermosetting film for forming a back surface protective film.

For example, the heating temperature during thermal curing is preferably 100 to 200°C, more preferably 110 to 180°C, and particularly preferably 120 to 170°C. The heating time during thermal curing is preferably 0.5 to 5 hours, more preferably 0.5 to 3 hours, and particularly preferably 1 to 2 hours. When thermal curing is performed in the curing process, it is preferable that the peeling process be performed before the curing process, taking into account the heat resistance of the circuit surface protection tape 17.

5 is a schematic cross-sectional view showing another embodiment of the method for producing the fourth laminate. The method for producing the fourth laminate of this embodiment includes, after the second lamination step, a peeling step (FIG. 5(e)) of peeling the circuit surface protection tape 17 from the circuit surface 14a of the workpiece 14, a curing step (FIG. 5(f')) of curing the back surface protection film forming film 13 to form the back surface protection film 13', and a step (FIG. 5(g')) of irradiating the back surface protection film 13' with a laser from the support sheet 10 side to perform laser marking.

<<Method of Manufacturing a Semiconductor Device with a Backside Protective Film>>
6 is a schematic cross-sectional view showing an example of an embodiment of the method for manufacturing a semiconductor device with a back surface protective film. The method for manufacturing a semiconductor device with a back surface protective film of this embodiment includes a step of dicing a work 14 and a back surface protective film 13' of a fourth stack 19' manufactured by the manufacturing method for the fourth stack to obtain a semiconductor device with a back surface protective film 21 (FIGS. 6(h) and 6(i)), and a step of picking up the semiconductor device with a back surface protective film 21 from a support sheet 10 (FIG. 6(j)).

7 is a schematic cross-sectional view showing another example of an embodiment of the method for manufacturing a semiconductor device with a back surface protective film. The method for manufacturing a semiconductor device with a back surface protective film of this embodiment includes a step of dicing the film for forming a back surface protective film 13 and the work 14 of the third laminate 19 manufactured by the manufacturing method of the third laminate to obtain a semiconductor device with a film for forming a back surface protective film 21' (FIGS. 7(h') and 7(i')), a step of picking up the semiconductor device with the film for forming a back surface protective film 21' from the support sheet 10 (FIG. 7(j')), and a curing step of curing the film for forming a back surface protective film 13 to obtain a back surface protective film 13' (FIG. 7(k')).

8 is a schematic cross-sectional view showing another embodiment of the method for manufacturing a semiconductor device with a back surface protective film. The method for manufacturing a semiconductor device with a back surface protective film of this embodiment includes a step of dicing the film for forming a back surface protective film 13 and the workpiece 14 of the third laminate 19 manufactured by the manufacturing method for the third laminate to obtain a semiconductor device with a film for forming a back surface protective film 21' (FIGS. 8(h) and 8(i)), a hardening step of hardening the film for forming a back surface protective film 13 to obtain a back surface protective film 13' (FIG. 8(j')), and a step of picking up the semiconductor device with a back surface protective film 21 from the support sheet 10.

In the manufacturing method of the semiconductor device with a back surface protective film of this embodiment, the film 13 for forming the back surface protective film is thermosetting, and in the process of forming the back surface protective film of this embodiment, for example, the film 13 for forming the back surface protective film is thermally cured under conditions of 130°C and 2 hours.

The curing conditions when the thermosetting film for forming a back surface protective film is thermally cured to form the back surface protective film are not particularly limited as long as the degree of curing is such that the back surface protective film can fully perform its function, as described above, and may be appropriately selected depending on the type of thermosetting film for forming a back surface protective film.

In the manufacturing method of a semiconductor device with a back surface protective film of this embodiment, the film 13 for forming the back surface protective film may be energy ray curable, and the process of forming the back surface protective film may be a process of irradiating the film 13 for forming the back surface protective film with energy rays to cause it to be energy ray cured.

The curing conditions when the energy ray-curable film for forming a back surface protective film is cured with energy rays to form a protective film are not particularly limited as long as the protective film has a degree of curing that allows it to fully exert its function, and may be appropriately selected depending on the type of energy ray-curable film for forming a back surface protective film.
For example, the illuminance of the energy rays during energy ray curing of the energy ray-curable film for forming a back surface protection film is preferably 4 to 280 mW/cm ^2. The amount of energy rays during the curing is preferably 3 to 1000 mJ/cm ² .

As energy ray curable films for forming rear surface protective films, for example, those disclosed in International Publication No. 2017/188200 and International Publication No. 2017/188218 can be used.

The manufacturing method of the third laminate of the present invention can be used to manufacture a semiconductor device with a back surface protective film.

1: Composite sheet for forming protective film, 5: First laminate, 6: Second laminate, 7: Semiconductor chip with back surface protective film, 8: Semiconductor wafer, 8b: Back surface of semiconductor wafer, 9: Semiconductor chip, 10: Support sheet, 11: Substrate, 12: Adhesive layer, 13: Film for forming back surface protective film, 13': Back surface protective film, 13a: Exposed surface after peeling off release film 151 of film for forming back surface protective film, 13b: Exposed surface after peeling off release film 152 of film for forming back surface protective film, Reference Signs List 14: Work, 14a: Circuit surface of work, 14b: Back surface of work, 151: First release film, 152: Second release film, 16: Adhesive layer for jig, 17: Tape for protecting circuit surface, 18: Fixing jig, 19: Third laminate, 19': Fourth laminate, 20: Semiconductor device, 21: Semiconductor device with back surface protective film, 21': Semiconductor device with film for forming back surface protective film, 62: Electronic component, 63: Circuit board, 63a: Terminal forming surface, 64: Sealing resin layer

Claims (4)

A method for producing a third laminate in which a workpiece, a film for forming a back surface protection film, and a support sheet are laminated in this order, comprising:
One surface of the workpiece is a circuit surface, and the other surface is a back surface,
A first lamination step of attaching the film for forming a back surface protection film processed into the shape of the work to the back surface side of the work;
A second lamination step of attaching the support sheet to the film for forming a back surface protection film,
Between the first lamination step and the second lamination step, a second laminate in which the film for forming a back surface protection film is laminated on the work is transported one by one;
A method for producing a third laminate, in which the steps from the first lamination step to the second lamination step are performed by connecting an apparatus for applying a film for forming a back surface protection film and an apparatus for applying a support sheet, or by performing these steps within the same apparatus. A method for producing a third laminate in which a workpiece, a film for forming a back surface protection film, and a support sheet are laminated in this order, comprising:
One surface of the workpiece is a circuit surface, and the other surface is a back surface,
A first lamination step of attaching the film for forming a back surface protection film processed into the shape of the work to the back surface side of the work;
A second lamination step of attaching the support sheet to the film for forming a back surface protection film,
A conveying distance of the work from a bonding start point of the first lamination process to a bonding completion point of the second lamination process is 7000 mm or less;
A method for producing a third laminate, in which the steps from the first lamination step to the second lamination step are performed by connecting an apparatus for applying a film for forming a back surface protection film and an apparatus for applying a support sheet, or by performing these steps within the same apparatus. A method for producing a third laminate in which a workpiece, a film for forming a back surface protection film, and a support sheet are laminated in this order, comprising:
One surface of the workpiece is a circuit surface, and the other surface is a back surface,
A first lamination step of attaching the film for forming a back surface protection film processed into the shape of the work to the back surface side of the work;
A second lamination step of attaching the support sheet to the film for forming a back surface protection film,
The conveying time of the work from the start of attachment in the first lamination process to the completion of attachment in the second lamination process is 400 s or less;
A method for producing a third laminate, in which the steps from the first lamination step to the second lamination step are performed by connecting an apparatus for applying a film for forming a back surface protection film and an apparatus for applying a support sheet, or by performing these steps within the same apparatus. The method for manufacturing the third laminate described in claim 3, wherein the transport time of the workpiece from the start of attachment in the first lamination process to the completion of attachment in the second lamination process is 150 seconds or less.

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