JP7540885B2 - Kit and method for producing third laminate using said kit - Google Patents

Description

The present invention relates to a kit and a method for manufacturing a third laminate using the kit. More specifically, the present invention relates to a kit including a first laminate in which a first release film, a protective film-forming film, and a second release film are laminated in this order, a workpiece such as a semiconductor wafer to be protected by the protective film-forming film, and a support sheet used to support the protective film-forming film, and a method for manufacturing a third laminate in which a workpiece, the protective film-forming film, and the support sheet are laminated in this order using the kit in an in-line process.
Here, "inline process" refers to a process that is carried out in a single piece of equipment, or in a single piece of equipment, in which one or more processes are performed in multiple connected pieces of equipment, and which includes multiple processes and the transport that connects the processes, and in which workpieces are transported one by one between one process and the next.

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 as a protective film on the back surface of this exposed semiconductor chip, and the semiconductor chip with the protective film may be incorporated into a semiconductor device. The protective film is used to prevent cracks from occurring in the semiconductor chip after the dicing process and packaging (for example, Patent Documents 1 to 4).

Such a semiconductor chip with a protective film is manufactured, for example, through the process shown in FIG. 8. That is, a method is known in which a protective film-forming film 13 is laminated on the back surface 8b of a semiconductor wafer 8 having a circuit surface (FIG. 8(A)), the protective film-forming film 13 is thermally cured or energy ray cured to form a protective film 13' (FIG. 8(B)), a support sheet 10 is laminated on the protective film 13' (FIG. 8(D)), the semiconductor wafer 8 and the protective film 13' are diced to form a semiconductor chip 7 with a protective film (FIGS. 8(E) and 8(F)), and the semiconductor chip 7 with a protective film is picked up from the support sheet 10. Here, the device for attaching the protective film-forming film 13 to the back surface 8b of the semiconductor wafer 8 in FIG. 8(A) and the device for attaching the support sheet 10 to the protective film 13' in FIG. 8(D) are separate devices.

In addition, a composite sheet for forming a protective film, in which a protective film-forming film 13 and a support sheet 10 are integrated, is used in the manufacture of semiconductor chips with a protective film (e.g., Patent Documents 2, 3, and 4).

A method for manufacturing a semiconductor chip with a protective film using a composite sheet for forming a protective film includes, for example, the steps shown in FIG. 9. That is, a method is known in which the protective film forming film 13 of the composite sheet for forming a protective film 3, which is made by laminating the protective film forming film 13 and the support sheet 10, is attached to the back surface 8b of a semiconductor wafer 8 having a circuit surface (FIG. 9(A')), the backgrind tape 17 is peeled off (FIG. 9(B')), the protective film forming film 13 is heat-cured or energy-ray-cured to form a protective film 13' (FIG. 9(C')), the semiconductor wafer 8 and the protective film 13' are diced to form a semiconductor chip 7 with a protective film (FIG. 9(E') and FIG. 9(F')), and the semiconductor chip 7 with a protective film is picked up from the support sheet 10.

Patent No. 4271597 International Publication No. 2014/157426 Patent No. 5363662 JP 2016-225496 A

In the conventional method for manufacturing a semiconductor chip with a protective film shown in FIG. 8, the workpiece to be protected by the protective film-forming film 13 (i.e., the semiconductor wafer 8) is one from which the backgrind tape has already been peeled off. The protective film-forming film 13 is laminated on the back surface 8b of the semiconductor wafer 8 (FIG. 8(A)), and the protective film-forming film 13 is cured to form a protective film 13' (FIG. 8(B)), after which the support sheet 10 is attached to the protective film 13' (FIG. 8(D)). Therefore, separate devices are used for attaching the protective film-forming film 13 to the back surface 8b of the semiconductor wafer 8 and for attaching the support sheet 10 to the protective film 13', and it is difficult to make these steps into an in-line process.

In the conventional method for manufacturing a semiconductor chip with a protective film shown in FIG. 9, a composite sheet 3 for forming a protective film, in which a protective film-forming film 13 and a support sheet 10 are integrated, is used, so that the process of attaching the protective film-forming film 13 to the workpiece (i.e., semiconductor wafer 8) to be protected by the protective film-forming film 13 and the process of attaching the support sheet 10 can be combined into one process. However, when the composite sheet 3 for forming a protective film is used, the characteristics of the protective film-forming film 13 and the characteristics of the support sheet 10 must be combined, and many types of composite sheets 3 for forming a protective film must be prepared in order to manufacture a semiconductor chip with a protective film that meets the purpose. In addition, the burden of manufacturing costs such as punching processing in order to prepare the composite sheet 3 for forming a protective film becomes an issue. Furthermore, when the composite sheet 3 for forming a protective film is used, there is a risk that the tape will meander in the mounter device after the tape roll is installed in the mounting process, and the first few sheets will not be attached as set in the attachment position or attachment tension.

When attempting to perform the process of attaching the protective film-forming film 13 to the back surface 8b of the semiconductor wafer 8 to which the backgrind tape 17 is attached and the process of attaching the support sheet 10 to the protective film-forming film 13 in an in-line process using the protective film-forming film 13 and support sheet 10 used in the conventional method for manufacturing semiconductor chips with a protective film shown in Figure 8, the backgrind tape 17 will be peeled off before the adhesion between the back surface 8b of the semiconductor wafer 8 and the protective film-forming film 13 is sufficient, which may result in peeling between the protective film-forming film 13 and the semiconductor wafer 8.

The present invention has been made in consideration of the above circumstances, and aims to provide a kit including a protective film-forming film and a support sheet that can be used to preferably manufacture a third laminate in an inline process, in which a workpiece such as a semiconductor wafer, a protective film-forming film capable of forming a protective film for protecting the back surface of the workpiece and improving the appearance, and a support sheet used to support the protective film-forming film are laminated in this order, and a method for manufacturing the third laminate using the kit in an inline process.

The present invention provides the following kit and a method for producing a third laminate using the kit.

[1] A kit comprising a first laminate in which a first release film, a protective film-forming film, and a second release film are laminated in this order, and a support sheet used to support a workpiece to be protected by the protective film-forming film and the protective film-forming film,
The protective film-forming film is attached to the mirror surface of a mirror-finished silicon wafer with a laminating roller at 70°C, and 5 minutes after the attachment, the 180° peel adhesion strength between the protective film-forming film and the silicon wafer measured at a peel speed of 100 mm/min and a temperature of 23°C is 900 mN/25 mm or more.
[2] The kit described in [1], wherein the first laminate is in a roll form.
[3] The kit described in [1] or [2] above, wherein the protective film-forming film is heat curable or energy ray curable.
[4] The kit according to any one of [1] to [3], wherein the support sheet has an adhesive layer to be attached to the protective film-forming film laminated on a substrate.
[5] The kit according to any one of [1] to [4], wherein the support sheet is attached to the protective film-forming film with a laminating roller at 23°C, and 3 minutes after the attachment, the 180° peel adhesion between the protective film-forming film and the support sheet measured at a peel speed of 100 mm/min and a temperature of 23°C is 100 mN/25 mm or more.

[6] A method for producing a third laminate in which a workpiece, the protective film-forming film, and the support sheet are laminated in this order, using the kit according to any one of [1] to [5] in an in-line process,
peeling off a first release film of the first laminate;
A first lamination step of attaching an exposed surface of the protective film-forming film to the workpiece;
A second lamination step of attaching the support sheet to the surface opposite to the exposed surface of the protective film-forming film,
A method for manufacturing a third laminate, wherein the transport distance of the work from the start point of attachment in the first lamination process to the completion point of attachment in the second lamination process is 7000 mm or less.

[7] A method for producing a third laminate in which a workpiece, the protective film-forming film, and the support sheet are laminated in this order, using the kit according to any one of [1] to [5] in an in-line process,
peeling off a first release film of the first laminate;
A first lamination step of attaching an exposed surface of the protective film-forming film to the workpiece;
A second lamination step of attaching the support sheet to the surface opposite to the exposed surface of the protective film-forming film,
A method for manufacturing a third laminate, 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 400 s or less.

[8] A method for producing a third laminate in which a workpiece, the protective film-forming film, and the support sheet are laminated in this order, using the kit according to any one of [1] to [5] in an in-line process,
peeling off a first release film of the first laminate;
A first lamination step of attaching an exposed surface of the protective film-forming film to the workpiece;
A second lamination step of attaching the support sheet to the surface opposite to the exposed surface of the protective film-forming film,
A method for manufacturing a third laminate, in which a second laminate having the protective film-forming film attached to the workpiece is transported one sheet at a time between the first lamination process and the second lamination process.

[9] A method for producing a third laminate described in any one of [6] to [8], comprising a backgrind tape attached to the surface of the workpiece opposite to the side to which the exposed surface of the protective film is attached, and a process for peeling off the backgrind tape from the workpiece after the second lamination process.
[10] The method for producing the third laminate described in [9], wherein the backgrind tape is started to be peeled off from the work in less than 10 minutes from the start of application in the first lamination process.

According to the present invention, a third laminate in which a workpiece such as a semiconductor wafer, a protective film-forming film capable of forming a protective film for protecting the back surface of the workpiece and improving the appearance, and a support sheet used to support the protective film-forming film are laminated in this order can be preferably manufactured in an inline process. A kit including the protective film-forming film and the support sheet, and a method for manufacturing a third laminate using the kit in an inline process are provided.

FIG. 1 is a schematic cross-sectional view showing an example of a kit according to the present embodiment. FIG. 2 is a cross-sectional outline diagram illustrating an example of a step of peeling off a first release film of a first laminate, in the method for producing a third laminate of the present embodiment. 4 is a cross-sectional schematic diagram illustrating an example of a first lamination step in the method for producing the third laminate of the present embodiment. FIG. 4 is a cross-sectional schematic diagram illustrating an example of a second lamination step in the method for producing the third laminate of the present embodiment. FIG. FIG. 13 is a schematic cross-sectional view showing an example in which the backgrind tape was successfully peeled off from the third laminate. This is a cross-sectional schematic diagram showing an example in which the backgrind tape peeled off between the protective film-forming film and the workpiece when peeled off from the third laminate, resulting in a defect. This is a cross-sectional schematic diagram showing an example in which, when the backgrind tape was peeled off from the third laminate, it peeled off between the protective film-forming film and the support sheet, resulting in a defect. 1 is a schematic cross-sectional view showing an example of a conventional method for manufacturing a semiconductor chip with a protective film. FIG. 11 is a schematic cross-sectional view showing another example of a conventional method for manufacturing a semiconductor chip with a protective film.

The following provides a detailed description of a kit that is an example of an embodiment of the present invention, and a method for manufacturing a third laminate using the kit. Note that the drawings used in the following description may show characteristic parts in an enlarged scale for the sake of clarity, and the dimensional ratios of each component may not necessarily be the same as in reality.

＜＜Kit＞＞
1 is a schematic cross-sectional view showing an example of the kit of the present embodiment. The kit of the present embodiment includes a first laminate 5 in which a first release film 151, a protective film-forming film 13, and a second release film 152 are laminated in this order, and a support sheet 10 used to support the workpiece to be protected by the protective film-forming film 13 and the protective film-forming film 13.

In this embodiment, the protective film-forming film 13 is applied to the mirror surface of a mirror-finished silicon wafer with a laminating roller at 70°C, and 5 minutes after the application, the 180° peel adhesion strength between the protective film-forming film 13 and the silicon wafer measured at a peel speed of 100 mm/min and a temperature of 23°C is 900 mN/25 mm or more.

It is preferable that one of the first release film 151 and the second release film 152 is a light-sided release film and the other is a heavy-sided release film. In this embodiment, the first release film 151 is a light-sided release film and the second release film 152 is a heavy-sided release film.

Examples of the support sheet 10 include a sheet composed only of a base material 11, and an adhesive sheet having an adhesive layer 12 on the base material 11. In this embodiment, the support sheet 10 has the adhesive layer 12 laminated on the base material 11, and after the second release film 152 of the protective film-forming film 13 is peeled off, the adhesive layer 12 of the support sheet 10 is attached to the second surface 13b on the second release film 152 side for use.

<<Method of manufacturing a third laminate using a kit>>
The manufacturing method of the third laminate in this embodiment is a manufacturing method of a third laminate in which a workpiece, a protective film-forming film 13 and a support sheet 10 are laminated in this order, using the kit in an in-line process, and includes, in this order, a step of peeling off the first release film 151 of the first laminate 5, a first lamination step of attaching the exposed surface of the protective film-forming film 13 (i.e., the first surface 13a of the protective film-forming film 13) to the workpiece, and a second lamination step of attaching the support sheet 10 to the surface of the protective film-forming film opposite the exposed surface (i.e., the second surface 13b of the protective film-forming film).

Figure 2 is an example of a method for using the first laminate 5, and is a schematic cross-sectional view showing an example of a process for peeling off the first release film of the first laminate in the manufacturing method of the third laminate of this embodiment.

The first laminate 5 (Fig. 2(a)) is, for example, applied with a circular punching blade 70 from the side of the first release film 151, which is the light release film (Fig. 2(b)), and the first release film 151 is peeled off (Fig. 2(c)).

Figure 3 is a schematic cross-sectional view showing an example of the first lamination step in the method for producing the third laminate of this embodiment.

In the first lamination process, the first release film 151 of the first laminate 5 is peeled off, and the exposed surface of the protective film-forming film 13 (i.e., the first surface 13a of the protective film-forming film 13) that has become circular is attached to the workpiece 14 to be protected (Fig. 3(a)) (Figs. 3(b) and 3(c)). Next, the second release film 152 is peeled off to expose the surface of the protective film-forming film 13 opposite to the exposed surface (i.e., the second surface 13b of the protective film-forming film) (Fig. 3(d)).

In this embodiment, the workpiece 14 is a semiconductor wafer having a circuit surface 14a on one side, and a backgrind tape 17 is attached to the circuit surface 14a of the workpiece 14.

Figure 4 is an example of a method for using the support sheet 10, and is a schematic cross-sectional view showing an example of the second lamination step in the method for producing the third laminate of this embodiment.

In the second lamination step, a support sheet 10 is attached to the surface of the protective film-forming film opposite the exposed surface (i.e., the second surface 13b of the protective film-forming film) of the second laminate 6 (Fig. 4(d)) in which the protective film-forming film 13 is attached to the workpiece 14 (Fig. 4(e) and Fig. 4(f)).

In the second lamination step shown in Fig. 4, the support sheet 10 is attached to the second surface 13b of the protective film-forming film 13 laminated on the back surface 14b of the workpiece 14. The support sheet 10 is, for example, a circular polypropylene film having a thickness of 80 μm, and is provided with a jig adhesive layer 16 on the outer periphery. In this embodiment, the workpiece 14 is fixed to a fixing jig 18 (for example, a ring frame) together with the protective film-forming film 13. Then, the support sheet 10 is attached to the second surface 13b of the protective film-forming film 13, and is fixed to the fixing jig 18 (for example, a ring frame) via the jig adhesive layer 16 (Fig. 4(e)).
If the support sheet 10 itself has sufficient adhesiveness to the fixing jig 18, the jig adhesive layer 16 does not necessarily have to be provided.

Conventionally, in Figure 8 (A), an apparatus for attaching a protective film-forming film 13 to the back surface 8b of a semiconductor wafer 8 and in Figure 8 (D), an apparatus for attaching a support sheet 10 to the protective film 13' were performed by separate apparatus, and each laminate was stored in a cassette (multiple laminates) and transported to the next apparatus.
However, in this embodiment, at least the first lamination step shown in Fig. 3 to the second lamination step shown in Fig. 4 can be performed in an apparatus in which the apparatus performing the first lamination step and the apparatus performing the second lamination step are connected, or in the same apparatus, and the second laminate 6 in which the protective film-forming film 13 is attached to the work 14 can be transported one by one between the first lamination step and the second lamination step. That is, the protective film-forming film 13 and the second laminate 6 of the work 14 can be transported to the second lamination step shown in Fig. 4 in an apparatus in which the apparatus performing the first lamination step and the apparatus performing the second lamination step are connected, or in the same apparatus, without being stored in a cassette. This makes it possible to suppress unintended adhesion of dust and improve production tact time, compared to when each step is performed in a separate apparatus.

In this embodiment, after the first lamination step, the step of peeling the second release film 152 on the second surface 13b side from the protective film-forming film 13 is also performed in an apparatus in which the apparatus performing the first lamination step and the apparatus performing the second lamination step are connected, or in the same apparatus. Before the first lamination step, the step of peeling the first release film 151 on the first surface 13a side from the protective film-forming film 13 of the first laminate 5 is also preferably performed in an apparatus in which the apparatus performing the first lamination step and the apparatus performing the second lamination step are connected, or in the same apparatus.

In this embodiment, the conveying distance of the work 14 from the attachment start point of the first lamination process shown in Fig. 3(b) to the attachment completion point of the second lamination process shown in Fig. 4(f) can be designed to be 7000 mm or less, and the device space can be reduced. The conveying distance of the work 14 from the attachment start point of the first lamination process shown in Fig. 3(b) to the attachment completion point of the second lamination process shown in Fig. 4(f) can be 6500 mm or less, 6000 mm or less, 4500 mm or less, or 3000 mm or less.
By keeping the transport distance of the workpiece 14 between the start point of the first lamination process and the end point of the second lamination process within the above range, the risk of unintended airborne debris adhering to the protective film-forming film can be reduced.

In this embodiment, the transport time of the work 14 from the start of attachment in the first lamination process shown in Fig. 3(b) to the completion of attachment in the second lamination process shown in Fig. 4(f) can be set to 400 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 shown in Fig. 3(b) to the completion of attachment in the second lamination process shown in Fig. 4(f) can be set to 350 seconds or less, 300 seconds or less, 250 seconds or less, 200 seconds or less, or 150 seconds or less.
By keeping the transport time of the workpiece 14 between the start of application in the first lamination process and the completion of application in the second lamination process below the upper limit value, the risk of unintended dust floating in the air adhering to the protective film forming film can be reduced.
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 50 seconds or more, 100 seconds or more, 150 seconds or more, or 200 seconds or more.
By making the transport time of the work 14 from the start of attachment in the first lamination process to the end of attachment in the second lamination process greater than the lower limit and not transporting too fast, the work can be held correctly without being dropped when the work is moved while being held by a mechanical arm during the process of transporting the work, and wear on the movable parts of the device can be reduced.

The speed at which the exposed surface of the protective film-forming film 13 is attached to the work 14 in the first lamination step, and the speed at which the support sheet 10 is attached to the surface opposite to the exposed surface of 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 the above upper limit value or less, the adhesion between the work 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.

In this embodiment, the second surface 10b of the support sheet 10, opposite the protective film-forming film 13, is then attached to the suction table 80 in an apparatus in which the apparatus performing the first lamination process and the apparatus performing the second lamination process are connected, or in the same apparatus, and the backgrind tape 17 is peeled off from the third laminate 19. FIG. 5 is a schematic cross-sectional view showing an example in which the backgrind tape 17 has been successfully peeled off from the third laminate 19.

In this embodiment, the protective film-forming film 13 is applied to the mirror surface of a mirror-finished silicon wafer with a laminating roller at 70°C, and 5 minutes after the application, the 180° peel adhesion strength between the protective film-forming film 13 and the silicon wafer measured at a peel speed of 100 mm/min and a temperature of 23°C is 900 mN/25 mm or more.

The 180° peel adhesion between the protective film-forming film 13 and the silicon wafer 5 minutes after application is 900 mN/25 mm or more, which reduces the risk of peeling between the protective film-forming film 13 and the workpiece 14 when the backgrind tape 17 is peeled off. Figure 6 is a schematic cross-sectional view showing an example in which peeling occurs between the protective film-forming film 13 and the workpiece 14 when the backgrind tape 17 is peeled off from the third laminate 19, resulting in a defect.

The manufacturing method of the third laminate of this embodiment using the kit of this embodiment uses the kit in an in-line process. In this embodiment, after the second lamination process, the process of peeling the backgrind tape from the work is also performed in an apparatus that connects the apparatus that performs the first lamination process and the apparatus that performs the second lamination process, or in the same apparatus, and is performed in an in-line process. The manufacturing method of the third laminate of this embodiment can start peeling the backgrind tape from the work in less than 10 minutes from the start of application in the first lamination process. This reduces the risk of mutual migration between the material contained in the support sheet 10 and the material contained in the protective film-forming film 13.

When applying the conventional protective film-forming film 13 used in the manufacturing method of the semiconductor chip with protective film shown in FIG. 8 to the manufacturing method of the third laminate of this embodiment, the first lamination process of attaching the protective film-forming film 13 to the workpiece 14 and the second lamination process of attaching the support sheet 10 to the protective film-forming film 13 are performed in an in-line process in the manufacturing method of the third laminate of this embodiment, so that the backgrind tape 17 is peeled off before the adhesive force between the workpiece 14 and the protective film-forming film 13 is strong. Therefore, when peeling the backgrind tape 17 from the third laminate 19, there is a risk of peeling between the workpiece 14 and the protective film-forming film 13.

In the kit of this embodiment, as described above, the protective film-forming film 13 is applied to the mirror surface of a mirror-finished silicon wafer with a laminating roller at 70°C, and 5 minutes after the application, the 180° peel adhesion between the protective film-forming film 13 and the silicon wafer is 900 mN/25 mm or more. Since the 180° peel adhesion between the protective film-forming film 13 and the silicon wafer becomes strong within a short time after the application, the risk of peeling between the protective film-forming film 13 and the workpiece 14 is reduced when the backgrind tape 17 is peeled off.

Five minutes after application, the 180° peel adhesion strength between the protective film-forming film 13 and the silicon wafer is preferably 950 mN/25 mm or more, more preferably 1050 mN/25 mm or more, and particularly preferably 1150 mN/25 mm or more.

The 180° peel adhesion between the protective film-forming film 13 and the silicon wafer 30 minutes after application is preferably 1100 mN/25 mm or more, more preferably 1150 mN/25 mm or more, and particularly preferably 1200 mN/25 mm or more, from the viewpoint of preventing unintended peeling during the process of transportation after peeling off the backgrind tape.

In this embodiment, the support sheet 10 is attached to the protective film-forming film 13 with a laminating roller at 23°C, and 3 minutes after the attachment, the 180° peel adhesion between the protective film-forming film 13 and the support sheet 10, measured at a peel speed of 100 mm/min and a temperature of 23°C, is preferably 100 mN/25 mm or more.

The 180° peel adhesion between the protective film-forming film 13 and the support sheet 10 3 minutes after application is 100 mN/25 mm or more, which reduces the risk of peeling between the protective film-forming film 13 and the support sheet 10 when the backgrind tape 17 is peeled off. Figure 7 is a schematic cross-sectional view showing an example in which peeling occurs between the protective film-forming film 13 and the support sheet 10 when the backgrind tape 17 is peeled off from the third laminate 19, resulting in a defect.

The 180° peel adhesion between the protective film-forming film 13 and the support sheet 10 3 minutes after application may be 110 mN/25 mm or more, 120 mN/25 mm or more, 130 mN/25 mm or more, 180 mN/25 mm or more, or 230 mN/25 mm or more.

The 180° peel adhesion between the protective film-forming film 13 and the support sheet 10 30 minutes after application is preferably 120 mN/25 mm or more, more preferably 200 mN/25 mm or more, and particularly preferably 220 mN/25 mm or more, from the viewpoint of preventing unintended peeling in the process after peeling of the backgrind tape.

In this embodiment, a semiconductor wafer is used as the workpiece 14 shown in FIG. 3(a). One surface of the semiconductor wafer is the circuit surface 14a, on which bumps are formed. In order to prevent the circuit surface 14a and bumps of the semiconductor wafer from being crushed during back grinding of the semiconductor wafer, and to prevent dimples and cracks from occurring on the back surface of the wafer, the circuit surface 14a and bumps of the semiconductor wafer are protected by a circuit surface protection tape. The circuit surface protection tape is a back grind tape 17, and the back surface of the semiconductor wafer, which is the workpiece 14 (i.e., the back surface 14b of the workpiece), is the ground surface.

The workpiece 14 is not limited as long as it has a circuit surface 14a on one side and the other side can be considered a back surface. Examples of the workpiece 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 diced and sealed with sealing resin, and one side of the panel has a terminal formation surface (in other words, a circuit surface) of the terminal-equipped semiconductor device.

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

<First laminate>
The first laminate 5 can be prepared, for example, as follows. A protective film-forming composition containing a solvent is applied to the release surface of the second release film 152 having a thickness of 38 μm using a knife coater, and then dried in an oven at 120° C. for 2 minutes to form a protective film-forming film. Next, the release surface of the first release film 151 having a thickness of 38 μm is superimposed on the protective film-forming film, and the two are bonded together to obtain the first laminate 5 consisting of the first release film 151, the protective film-forming film (thickness: 25 μm), and the second release film 152. Such a first laminate 5 is suitable for storage, for example, in a roll form.

The first laminate 5 can be prepared by making the release surface of the first release film 151 a rough surface having a surface roughness Ra of, for example, 200 nm, and making the release surface of the second release film 152 a smooth surface that is smoother than the rough surface, having a surface roughness Ra of, for example, 30 nm.

Alternatively, even if the surface roughness Ra of the release surface of the first release film 151 and the surface roughness of the release surface of the second release film 152 are the same smooth surface, the first laminate 5 can be prepared, for example, as follows.

That is, a protective film-forming composition containing a solvent is applied to the release surface of the second release film 152 having a surface roughness Ra of 30 nm using a knife coater, and then dried in an oven at 120°C for 2 minutes to form a protective film-forming film. Next, the release surface of the first release film 151 having a thickness of 38 μm and a surface roughness Ra of 30 nm is superimposed on the protective film-forming film, and the two are laminated together under conditions of, for example, 23°C and 0.4 MPa to obtain a protective film-forming film consisting of the first release film 151, the protective film-forming film 13 (thickness: 25 μm), and the second release film 152. As a result, a light release surface is formed between the first surface 13a of the protective film-forming film 13 and the first release film 151, and a heavy release surface with a peel strength greater than that of the light release surface is formed between the second surface 13b of the protective film-forming film 13 and the second release film 152. Such a first laminate 5 is also suitable for storage, for example, in a roll form.

The surface roughness of the first peelable film 151 side of the protective film-forming film can be adjusted by adjusting the temperature and pressure conditions for laminating the peelable surface of the first peelable film 151 to the protective film-forming film. By increasing the temperature and pressure conditions for laminating the peelable surface of the first peelable film 151 to the protective film-forming film, the surface roughness of the first peelable film 151 side of the protective film-forming film becomes faithful to the surface roughness of the peelable surface of the first peelable film 151.

The surface roughness Ra of the rough surface of the protective film-forming film that faces the back side of the workpiece may be 32 to 1200 nm, preferably 32 to 1000 nm, more preferably 32 to 900 nm, and particularly preferably 32 to 800 nm.

The larger the surface roughness Ra of the rough surface of the protective film-forming film, the smaller the area of contact with the release film will be. Therefore, by having the surface roughness Ra of the rough surface of the protective film-forming film be equal to or greater than the lower limit, the rough surface of the protective film-forming film is preferentially peeled off when peeling the film from the rough surface side.
This reduces the risk of poor peeling, known as peeling failure, in which, when peeling off the light release film, the protective film-forming film does not peel properly from the light release and part of the protective film-forming film remains on the light release film.

The surface roughness Ra of the smooth surface of the protective film-forming film facing the support sheet is preferably 20 to 80 nm, more preferably 24 to 50 nm, and even more preferably 28 to 32 nm.

The ratio of the surface roughness Ra of the rough surface of the protective film-forming film to the surface roughness Ra of the smooth surface of the protective film-forming film (surface roughness Ra of rough surface/surface roughness Ra of smooth surface) may be 1.1 to 50, 1.2 to 45, 1.3 to 35, 1.4 to 30, or 1.5 to 24.

(Protective film forming composition)
As the composition of the protective film-forming composition for forming the protective film-forming film, in applications where strong protective performance is not required, a protective film-forming composition that does not contain a curable component can be used, and a curing process is not required. Therefore, it is easy to use. However, depending on the fragile chip, it may not be possible to obtain sufficient adhesion and protective performance. It is preferred that the composition contains a polymer component and a curable component.

The polymer component may also be considered as a curable component. In this specification, when the protective film-forming composition contains a component that is both a polymer component and a curable component, the protective film-forming composition is considered to contain a polymer component and a curable component.

(Polymer Component)
A polymer component is used to impart sufficient adhesion and film-forming properties (sheet-forming properties) to the protective film-forming film. Examples of the polymer component that can be used include acrylic polymers, polyester resins, urethane resins, acrylic urethane resins, silicone resins, and rubber-based polymers.

The weight average molecular weight (Mw) of the polymer component is preferably 10,000 to 2,000,000, and more preferably 100,000 to 1,200,000. When the weight average molecular weight of the polymer component is equal to or greater than the lower limit, the release film is easier to peel off, reducing the risk of poor peeling, known as "nakiwakare." When the weight average molecular weight of the polymer component is equal to or less than the upper limit, the protective film-forming film is prevented from becoming unable to be attached to the workpiece due to a decrease in adhesion, and the protective film-forming film is prevented from peeling off from the workpiece after attachment.

As the polymer component, an acrylic polymer is preferably used. The glass transition temperature (Tg) of the acrylic polymer is preferably in the range of -60 to 50°C, more preferably -50 to 40°C, and particularly preferably -40 to 30°C.
When the glass transition temperature of the acrylic polymer is equal to or higher than the lower limit, the release film becomes easy to peel off, and the risk of peeling failure called "nakiwakare" is reduced. When the glass transition temperature of the acrylic polymer is equal to or lower than the upper limit, the protective film-forming film is prevented from becoming unable to be attached to the workpiece due to a decrease in adhesion, the protective film-forming film is prevented from peeling off from the workpiece after attachment, and the risk of cracking (cracking) when the protective film-forming film is bent in a roll body is reduced.

From the viewpoint of adhesion, tackiness and film-forming properties, the preferred content of the polymer component is 5 to 50 parts by mass, 10 to 45 parts by mass, 14 to 40 parts by mass, or 18 to 35 parts by mass relative to the total weight of the protective film-forming film (100).

The glass transition temperature (Tg) of the resin constituting the polymer component can be calculated using the Fox formula shown below.
1/Tg=(W1/Tg1)+(W2/Tg2)+...+(Wm/Tgm)
(In the formula, Tg is the glass transition temperature of the resin constituting the polymer component, Tg1, Tg2, ... Tgm are the glass transition temperatures of homopolymers of the monomers that are raw materials for the resin constituting the polymer component, and W1, W2, ... Wm are the mass fractions of the monomers, provided that W1 + W2 + ... + Wm = 1.)
The glass transition temperature of the homopolymer of each monomer in the Fox formula can be the value described in the Polymer Data Handbook, the Adhesive Handbook, the Polymer Handbook, etc. For example, the glass transition temperatures of homopolymers are 10°C for methyl acrylate, 105°C for methyl methacrylate, -15°C for 2-hydroxyethyl acrylate, -54°C for n-butyl acrylate, and 41°C for glycidyl methacrylate.

Examples of monomers constituting the acrylic polymer 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. The acrylic polymer is preferably an acrylic polymer containing a monomer having a hydroxyl group, since it has good compatibility with the curable component described later. In addition, the acrylic polymer may be copolymerized with acrylic acid, methacrylic acid, itaconic acid, vinyl acetate, acrylonitrile, styrene, etc.

Furthermore, a thermoplastic resin may be blended as a 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 protective film-forming film can conform to the transfer surface of the protective film-forming film, suppressing the occurrence of voids, etc.

(Curing component)
The curable component is a thermosetting component and/or an energy ray curable component, whereby the protective film-forming film can be made thermosetting and/or energy ray curable.

By using a thermosetting protective film-forming film, the protective film-forming film can be easily thermally cured even when it is thick, making it possible to produce a thick protective film-forming film with good protective performance. In the heat curing process, multiple workpieces can be cured at once.

By using an energy ray curable protective film, the protective film can be cured with energy rays in a short time.

Thermosetting resins and thermosetting agents are used as the thermosetting components. For example, epoxy resins are preferred as thermosetting resins.

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 resin, dicyclopentadiene type epoxy resin, biphenyl type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, and phenylene skeleton type epoxy resin, 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.

The preferred content of the thermosetting component is preferably 1 to 75 parts by mass, more preferably 2 to 60 parts by mass, and even more preferably 3 to 50 parts by mass, relative to the total weight of the protective film-forming film (100). For example, it may be 4 to 40 parts by mass, 5 to 35 parts by mass, or 6 to 30 parts by mass.
When the content of the thermosetting resin is equal to or greater than the lower limit, the protective film can have sufficient adhesion to the workpiece, and the protective film has excellent performance in protecting the workpiece. When the content of the thermosetting resin is equal to or less than the upper limit, the protective film has excellent storage stability when stored as a roll.

Thermosetting agents function as curing agents 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 even 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 thermosetting agent is preferably 0.1 to 500 parts by mass, and more preferably 1 to 200 parts by mass, per 100 parts by mass of the thermosetting resin. If the content of the thermosetting agent is equal to or greater than the lower limit, the resin will be sufficiently cured and adhesive, and if the content is equal to or less than the upper limit, the moisture absorption rate of the protective film will be suppressed, improving the adhesive reliability between the workpiece and the protective film.

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 preferred content of the energy ray curable component is 1 to 80 parts by mass, more preferably 2 to 70 parts by mass, and even more preferably 3 to 60 parts by mass, relative to the total weight of the protective film-forming film (100), and may be, for example, 4 to 50 parts by mass or 5 to 40 parts by mass.

In addition, as the energy ray curable component, an energy ray curable polymer in which an energy ray polymerizable group is bonded to the main chain or side chain of a polymer component may be used. Such an energy ray curable polymer has both the function of a 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 polymer, which is a commonly used polymer component, or may be polyester, polyether, etc., but it is particularly preferable to use an acrylic polymer as the main skeleton because it is easy to synthesize and control the physical properties.

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

The energy beam curable polymer is obtained by reacting an acrylic polymer 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 polymer 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.

(Meth)acrylic monomers or derivatives thereof having functional groups such as hydroxyl groups, carboxyl groups, amino groups, substituted amino groups, and epoxy groups include, for example, 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. Furthermore, the above acrylic polymer 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 polymer component may be used in combination. The relationship of the blending amounts of these three components in the protective film-forming 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 polymer component.

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

The curing conditions when the energy ray-curable protective film-forming 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 exhibit its functions, and may be appropriately selected depending on the type of energy ray-curable protective film-forming film.
For example, the illuminance of the energy ray during energy ray curing of the energy ray curable protective film-forming film is preferably 4 to 280 mW/cm ^2. The amount of energy ray during the curing is preferably 3 to 1000 mJ/cm ² .

The protective film-forming film may contain the following components in addition to the above polymer components and curable components.

(Coloring Agent)
The protective film-forming film preferably contains a colorant. By blending a colorant into the protective film-forming film, when the semiconductor device is incorporated into an apparatus, infrared rays and the like generated from the surrounding devices can be shielded, and malfunction of the semiconductor device due to these can be prevented. Also, when a product number or the like is printed on the protective film obtained by curing the protective film-forming film, the visibility of the characters 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 a 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 the visibility is improved. As the colorant, organic or inorganic pigments and dyes are used. Pigments are preferred from the viewpoint of heat resistance and the like. As pigments, carbon black, iron oxide, manganese dioxide, aniline black, activated carbon, and the like are used, but are not limited thereto. Among them, carbon black is particularly preferred from the viewpoint of handling and dispersibility. The colorant may be used alone or in combination of two or more kinds.

The amount of colorant blended is preferably 0.1 to 35 parts by mass, more preferably 0.5 to 25 parts by mass, and particularly preferably 1 to 15 parts by mass, per 100 parts by mass of the total solid content constituting the protective film-forming film.

(Cure Accelerator)
The curing accelerator is used to adjust the curing speed of the protective film-forming film. The curing accelerator is preferably used in particular 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 amount within the above range, the adhesive has excellent adhesive properties even when exposed to high temperature and high humidity, and can achieve high adhesive reliability even when exposed to severe reflow conditions.

(Coupling Agent)
The coupling agent may be used to improve the adhesive reliability of the protective film to the workpiece. In addition, by using the coupling agent, the water resistance of the protective film obtained by curing the protective film-forming 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 a polymer component, a 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, and imidazolesilane. These can be used alone or in combination of two or more.

The coupling agent is usually contained in a proportion 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, per 100 parts by mass of the polymer component and the curable component combined. If the content of the coupling agent is less than 0.1 parts by mass, the above effect may not be obtained, and if it exceeds 20 parts by mass, it may cause outgassing. By having the content of the coupling agent within the above range, it becomes easy to adjust the adhesive strength between the protective film-forming film and the support sheet after 3 minutes of application, and the adhesive strength between the protective film-forming film and the silicon wafer after 5 minutes of application.

(Filling material)
By blending a filler into the protective film-forming film, it becomes possible to adjust the thermal expansion coefficient of the protective film after curing, and by optimizing the thermal expansion coefficient of the protective film after curing with respect to the semiconductor chip, it is possible to improve the adhesion reliability between the workpiece and the protective film. As the filler, an inorganic filler is preferable. It is also possible to reduce the moisture absorption rate of the protective film after curing.

Preferred inorganic fillers include powders of silica, alumina, talc, calcium carbonate, titanium oxide, iron oxide, silicon carbide, boron nitride, etc., beads obtained by shaping these into spheres, single crystal fibers, glass fibers, etc. Among these, silica filler and alumina filler are preferred. The above inorganic fillers can be used alone or in combination of two or more. The content of the inorganic filler can be 1 to 85 parts by mass, 5 to 80 parts by mass, 10 to 75 parts by mass, 20 to 70 parts by mass, or 30 to 66 parts by mass, relative to 100 parts by mass of the total solid content constituting the protective film-forming film.
By making the content of the inorganic filler equal to or less than the upper limit, the risk of cracks (cracking) occurring when the protective film-forming film is bent in a roll body can be reduced, and by making the content equal to or more than the lower limit, the heat resistance of the protective film can be improved. In addition, by making the content of the inorganic filler within the above range, it becomes easy to adjust the adhesive strength between the protective film-forming film and the support sheet after 3 minutes of application, and the adhesive strength between the protective film-forming film and the silicon wafer after 5 minutes of application.

(Photopolymerization initiator)
When the protective film-forming film contains an energy ray-curable component as the above-mentioned curable component, the protective film-forming film is used by irradiating the energy ray such as ultraviolet rays to cure the energy ray-curable component. At this time, 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 it is above the lower limit, satisfactory protective performance can be obtained by photopolymerization, and if it is below the upper limit, the generation of residues that do not contribute to photopolymerization can be suppressed, and the curability of the protective film-forming film can be sufficient.

(Crosslinking Agent)
In order to adjust the adhesive strength and cohesiveness of the protective film-forming film with the workpiece, a crosslinking agent may be added. Examples of the crosslinking agent include an organic polyvalent isocyanate compound and an organic polyvalent imine compound.

The above-mentioned 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 total amount of the polymer component and the energy beam curable polymer.

(General purpose additive)
In addition to the above, various additives may be blended into the protective film-forming film as necessary. Examples of the various additives include a tackifier, 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.

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

The protective film-forming film obtained by applying and drying the protective film-forming composition composed of the above-mentioned components has adhesiveness and curing properties, and in the uncured state, it is adhered to a workpiece (such as a semiconductor wafer or chip) by pressing it against the workpiece. When pressing, the protective film-forming film may be heated. After curing, it is finally possible to provide a protective film with high impact resistance, excellent adhesive strength, and sufficient protective function even under harsh conditions of high temperature and high humidity. The protective film-forming 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 thickness of the protective film-forming film is not particularly limited, but can be 3 to 300 μm, 3 to 200 μm, 5 to 100 μm, 7 to 80 μm, 10 to 70 μm, 12 to 60 μm, 15 to 50 μm, 18 to 40 μm, or 20 to 30 μm.
When the thickness of the protective film-forming film is equal to or greater than the above lower limit, the protective performance of the protective film can be sufficient, and when the thickness is equal to or less than the above upper limit, costs can be reduced and energy rays can reach the inside of the energy ray-curable protective film-forming film.

<Support sheet>
The support sheet used in one embodiment of the present invention may be a sheet composed of only a substrate, or a pressure-sensitive adhesive sheet in which a pressure-sensitive adhesive layer is laminated on a substrate.
The support sheet serves as a release sheet that prevents dust and other particles from adhering to the surface of the protective film-forming film, or as a transport sheet that is attached to a fixing jig such as a ring frame and a workpiece with a protective film-forming film to enable the mechanical arm to hold and transport the fixing jig without directly touching the workpiece with the protective film-forming film.

The thickness of the support sheet is appropriately selected depending on the application, but from the viewpoint of improving the attachment to the workpiece with the protective film-forming film and the fixing jig, it is preferably 10 to 500 μm, more preferably 20 to 350 μm, and even more preferably 30 to 200 μm.
In addition, the thickness of the above-mentioned support sheet includes not only the thickness of the base material constituting the support sheet, but also the thickness of those layers and films if there is an adhesive layer, but does not include a release film, etc. that is not attached to the protective film-forming film.

(Substrate)
The substrate constituting the support sheet is preferably a resin film.
Examples of the resin film include polyethylene films such as low-density polyethylene (LDPE) film and linear low-density polyethylene (LLDPE) film, 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.
In addition, these resin films may be colored or printed. Furthermore, the resin film may be a sheet made by extruding a thermoplastic resin, may be a stretched film, or may be a sheet made by thinning and curing a curable resin by a predetermined 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.
In the case where the protective film-forming 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.

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)
In one embodiment of the present invention, the pressure-sensitive adhesive sheet used as the support sheet 10 includes a pressure-sensitive adhesive layer 12 formed from a pressure-sensitive adhesive on a substrate 11 such as the above-mentioned resin film. By having the pressure-sensitive adhesive layer 12, the 180° peel adhesive strength between the protective film-forming film and the support sheet can be easily adjusted.

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.
When attention is focused on the structure of the resin, examples of the adhesive resin include acrylic resins, urethane resins, rubber resins, silicone resins, vinyl ether resins, etc., and when attention is focused on the function of the resin, examples of the adhesive resin include energy ray curable adhesives, etc.
The 180° peel adhesion (β2) between the protective film formed from the protective film-forming film and the support sheet is preferably 0.03 to 4.0 N/25 mm, more preferably 0.05 to 2.5 N/25 mm, even more preferably 0.10 to 2.0 N/25 mm, and still more preferably 0.15 to 1.5 N/25 mm.
In one aspect of the present invention, from the viewpoint of adjusting the adhesive strength (β2) between the protective film and the support sheet within the above-mentioned range, as well as from the viewpoint of improving the pick-up properties, an adhesive sheet having an energy ray-curable adhesive layer formed from an adhesive composition containing an energy ray-curable resin, or an 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 addition, from the viewpoint of adjusting the 180° peel adhesion and adhesion (β2) between the protective film-forming film and the support sheet to the above-mentioned range, a pressure-sensitive adhesive containing an acrylic resin is preferable.
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 constituting the structural unit (a1) described 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 hydroxy group-containing monomers, carboxy group-containing monomers, and epoxy group-containing monomers, and specific examples of each of these monomers are the same as those exemplified as the monomers that constitute the structural unit (a2).
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 using an adhesive containing an acrylic resin, it is preferable to contain a crosslinking agent together with the acrylic resin from the viewpoint of adjusting the 180° peel adhesion and adhesion (β2) between the protective film-forming film and the support sheet within the above-mentioned range.
Examples of the crosslinking agent include isocyanate-based crosslinking agents, imine-based crosslinking agents, epoxy-based crosslinking agents, oxazoline-based crosslinking agents, carbodiimide-based crosslinking agents, etc., but from the viewpoint of adjusting the 180° peel adhesion and adhesion (β2) between the protective film-forming film and the support sheet to the above-mentioned 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 protective film-forming film has energy ray curing properties, the support sheet is preferably one that transmits energy rays.
For example, in order to optically inspect the protective film-forming film through the support sheet, the support sheet is preferably transparent.
From the viewpoint of improving the handling property, the support sheet may be provided with a release film before being attached to the protective film-forming film.

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

[Preparation of protective film-forming composition]
The following components were mixed in the respective compounding ratios (solid content equivalent) shown in Tables 1 and 2, and diluted with methyl ethyl ketone so that the solid content concentration was 50 mass% relative to the total mass of the protective film-forming composition, to prepare protective film-forming compositions of Examples 1 to 4 and Comparative Example 1 for forming protective film-forming films for semiconductor wafers.

(A-1): Polymer component: a (meth)acrylic copolymer (weight average molecular weight: 400,000) obtained by copolymerizing 90 parts by mass of methyl acrylate and 10 parts by mass of 2-hydroxyethyl acrylate. The glass transition temperature of this component is 7°C.
(A-2): Polymer component: an acrylic polymer (weight average molecular weight: 800,000) obtained by copolymerizing 55 parts by mass of n-butyl acrylate, 10 parts by mass of methyl acrylate, 20 parts by mass of glycidyl methacrylate, and 15 parts by mass of 2-hydroxyethyl acrylate. The glass transition temperature of this component is −28° C.

(B-1) Thermosetting resin: Bisphenol A type epoxy resin: Mitsubishi Chemical Corporation, jER828, epoxy equivalent 184 to 194 g/eq
(B-2) Thermosetting resin: Bisphenol A type epoxy resin: Mitsubishi Chemical Corporation, jER1055, epoxy equivalent 800 to 900 g/eq
(B-3) Thermosetting resin: dicyclopentadiene type epoxy resin: Epicron HP-7200HH, manufactured by DIC Corporation, epoxy equivalent 255 to 260 g/eq
(B-4) Thermosetting resin: dicyclopentadiene type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., XD-1000, epoxy equivalent 248 g/eq)
(B-5) Thermosetting resin: bisphenol A type epoxy resin with 20 parts of methyl methacrylate particles added (manufactured by Nippon Shokubai Co., Ltd., BPA328, epoxy equivalent 235 g/eq)

(C-1) Heat curing agent: Heat-activated latent epoxy resin curing agent (dicyandiamide (DICY7, manufactured by Mitsubishi Chemical, active hydrogen content 21 g/eq))
(D-1) Curing accelerator: 2-phenyl-4,5-dihydroxymethylimidazole (Curesol 2PHZ, manufactured by Shikoku Chemical Industry Co., Ltd.)
(E-1) Filler: Silica filler (manufactured by Admatechs Co., Ltd., SC205G-MMQ (average particle size 0.3 μm))
(E-2) Filler: Silica filler (manufactured by Tatsumori Co., Ltd., SV-10, average particle size 8.0 μm)
(E-3) Filler: Silica filler (manufactured by Admatechs Co., Ltd., SC2050MA, average particle size 0.5 μm)
(F-1) Colorant: Three-color mixed pigment (manufactured by Sanyo Pigment Co., Ltd., D1201M, solids concentration 30%).
(F-2) Colorant: Carbon black (Mitsubishi Chemical Corporation, MA600B)
(G-1) Silane coupling agent: X-41-1056, manufactured by Shin-Etsu Chemical Co., Ltd.
(G-2) Silane coupling agent: Mitsubishi Chemical Corporation, epoxy group-containing oligomer type MSEP-2

[Preparation of first laminate]
The protective film-forming compositions of Examples 1 to 4 and Comparative Example 1 obtained above were applied to the release-treated surface of a double-sided release film ("SP-PET501031" manufactured by Lintec Corporation, thickness 50 μm, corresponding to the second release film) made of a polyethylene terephthalate (PET) film, one side of which was treated for release by silicone treatment, and dried at 100° C. for 3 minutes to form protective film-forming films of Examples 1 to 4 and Comparative Example 1 having a thickness of 25 μm.
Furthermore, a release-treated surface of a light-sided release film ("SP-PET381031" manufactured by Lintec Corporation, thickness 38 μm, corresponding to the first release film) made by separately treating one side of a polyethylene terephthalate (PET) film with a silicone treatment was bonded to the exposed surface of this protective film-forming film (the surface opposite to the side provided with the release film) under conditions of temperature: 23±5°C, pressure: 0.4 MPa, and speed: 1 m/min to produce a laminated sheet in which release films were laminated on both sides of the protective film-forming film (i.e., the first laminate of Examples 1 to 4 and Comparative Example 1).

(Adhesive composition)
The adhesive composition used in producing the support sheet contained 100 parts by mass (solid content) of a (meth)acrylic acid alkyl ester copolymer and 45 parts by mass (solid content) of a trifunctional xylylene diisocyanate-based crosslinking agent ("Takenate D110N" manufactured by Mitsui Takeda Chemical Co., Ltd.), and the solid content concentration was adjusted to 30% by mass using a mixed solvent of methyl ethyl ketone, toluene and ethyl acetate.
The (meth)acrylic acid alkyl ester copolymer is an acrylic copolymer having a weight average molecular weight of 700,000 obtained by copolymerizing 50 parts by mass of 2-ethylhexyl acrylate (hereinafter, sometimes abbreviated as "2EHA"), 35 parts by mass of methyl methacrylate (hereinafter, sometimes abbreviated as "MMA"), and 15 parts by mass of 2-hydroxyethyl acrylate (hereinafter, sometimes abbreviated as "HEA").

[Manufacture of support sheet]
The pressure-sensitive adhesive composition was applied to the release-treated surface of a release film ("SP-PET381031" manufactured by Lintec Corporation, thickness 38 μm) and dried at 100° C. for 3 minutes to form a pressure-sensitive adhesive layer (thickness 10 μm after drying). A polypropylene film (thickness 80 μm, manufactured by Gunze Ltd.) serving as a substrate was separately bonded to the exposed surface (the surface opposite to the side provided with the release film) to obtain a support sheet with a release film having a configuration of substrate/pressure-sensitive adhesive layer/release film.

Hereinafter, the kit including the first laminate of Example 1 and the support sheet will be referred to as the kit of Example 1, and similarly, the kits including the first laminate of Examples 2 to 4 and the support sheet will be referred to as the kits of Examples 2 to 4, respectively, and the kit including the first laminate of Comparative Example 1 and the support sheet will be referred to as the kit of Comparative Example 1.

<Adhesive strength between protective film-forming film and silicon wafer after 5 minutes of application>
The light release film of the first laminate (composed of light release film/protective film-forming film/heavy release film) of Examples 1 to 4 and Comparative Example 1 was peeled off, and an adhesive tape manufactured by Lintec Corporation (product name PET50 PL Thin: acrylic adhesive layer/50 μm PET substrate) was laminated on the exposed surface at 23° C. to prepare laminate samples of Examples 1 to 4 and Comparative Example 1 consisting of PET substrate/acrylic adhesive layer/protective film-forming film/heavy release film. The laminate sample was cut into a rectangular shape having a width of 25 mm and a length of 250 mm. All of these operations were carried out in an environment of 23° C.

Separate from the actual process evaluation, a mirror-finished silicon wafer having a thickness of 600 μm was prepared.
The heavy release film of the laminate samples of Examples 1 to 4 and Comparative Example 1 was peeled off, and the exposed surface of the protective film-forming film was attached to the mirror surface of a mirror-finished 600 μm thick silicon wafer at a pressure of 0.3 MPa using a laminator with a roll heated to 70° C.
The adhesive strength was measured in an environment of 23° C. without heating and after 5 minutes (±0.5 minutes) had passed since application, by starting a 180° peeling motion using the measurement method described below.

Measurement method: Using a universal tensile tester (manufactured by Shimadzu Corporation, product name "Autograph AG-IS"), measurements were performed in accordance with JIS Z0237:2009, over a measurement distance of 100 mm, at a peel rate of 100 mm/min, and at a temperature of 23°C.
The average of the measured values over 80 mm, excluding the first 10 mm and the last 10 mm of the measurement distance, was taken as the "180° peel adhesion strength between the protective film-forming film and the silicon wafer."

<Adhesive strength between protective film-forming film and silicon wafer after 30 minutes of application>
The exposed surface of each of the protective film-forming films of Examples 1 to 4 and Comparative Example 1 was attached to the mirror surface of a 600 μm-thick mirror-finished silicon wafer at a pressure of 0.3 MPa using a laminator with a roll heated to 70° C.
The protective film-forming film was left to stand without heating in an environment of 23° C., and after 30 minutes (±0.5 minutes) had passed since application, a 180° peeling was started between the protective film-forming film and the silicon wafer to measure the adhesive strength.

<Adhesive strength between protective film-forming film and support sheet after 3 minutes of application>
A double-sided fixing tape (adhesive layer/PET film/adhesive layer) was attached to a SUS plate to prepare an adherend consisting of "adhesive layer/PET/adhesive layer/SUS plate."

The light release film of the first laminate (composed of light release film/protective film-forming film/heavy release film) of Examples 1 to 4 and Comparative Example 1 was peeled off, and the exposed surface of this protective film-forming film was attached to the adhesive layer of the adherend, to obtain a laminate consisting of SUS plate/adhesive layer/PET film/adhesive layer/protective film-forming film/heavy release film.

The support sheet was cut into a rectangular shape with a width of 25 mm and a length of 250 mm. In addition, the heavy release film of the laminate consisting of SUS plate/adhesive layer/PET film/adhesive layer/protective film-forming film/heavy release film was peeled off to produce the laminates of Examples 1 to 4 and Comparative Example 1 consisting of SUS plate/adhesive layer/PET film/adhesive layer/protective film-forming film. All of these operations were carried out in an environment of 23°C.

The adhesive layer of the rectangular support sheet was attached to the exposed surface of the protective film-forming film of the laminates of Examples 1 to 4 and Comparative Example 1, which consisted of SUS plate/adhesive layer/PET film/adhesive layer/protective film-forming film, at a pressure of 0.3 MPa using a laminator (roll temperature 23°C).

The tape was left unheated in a 23°C environment, and after 3 minutes (±0.5 minutes) had passed since application, the tape was peeled off at a 180° angle using the measurement method below to measure adhesive strength.

Measurement method: Using a universal tensile tester (manufactured by Shimadzu Corporation, product name "Autograph AG-IS"), measurements were performed in accordance with JIS Z0237:2009, over a measurement distance of 100 mm, at a peel rate of 100 mm/min, and at a temperature of 23°C.
The average of the measured values over a 80 mm measurement distance excluding the first 10 mm and the last 10 mm was taken as the "180° peel adhesion strength between the protective film-forming film and the support sheet."

<Adhesive strength between protective film-forming film and support sheet after 30 minutes of application>
Similarly, the adhesive layer of the rectangular support sheet was attached to the exposed surface of each of the protective film-forming films of Examples 1 to 4 and Comparative Example 1 at a pressure of 0.3 MPa using a laminator (roll temperature 23° C.).
The film was left unheated in a 23°C environment, and after 30 minutes (±0.5 minutes) had passed since application, the protective film-forming film and the support sheet were peeled off at 180° to measure the adhesive strength.

[Preparation of third laminate]
As a workpiece for evaluating peeling in an actual process, a 12-inch silicon wafer (thickness 40 μm) with a backgrind tape attached, which was mirror-finished using a backgrind tape (manufactured by Lintec Corporation, Adwill E-8180HR), was used.
In order to prepare a third laminate for evaluation of the actual process, an in-line device was assembled by connecting a bonding device ("RAD-3600F/12" manufactured by Lintec Corporation) and a bonding device ("RAD-2700F/12" manufactured by Lintec Corporation) so that a 12-inch silicon wafer workpiece with a backgrind tape could be transported by a mechanical arm.

The first release film was peeled off from the laminated sheet (i.e., the first laminate of Examples 1 to 4 and Comparative Example 1) in which the second release film/protective film-forming film/first release film were laminated in this order, and the exposed surface of the protective film-forming film was attached to the mirror-finished back surface of the 12-inch silicon wafer (thickness 40 μm) with the backgrind tape using an attachment device ("RAD-3600F/12" manufactured by Lintec Corporation) under conditions of lamination roll temperature: 70°C, attachment speed: 50 mm/s, and pressure: 0.3 MPa, to obtain the second laminate of Examples 1 to 4 and Comparative Example 1 in which the second release film/protective film-forming film/silicon wafer/backgrind tape were laminated in this order.

Next, the second release film was peeled off from the second laminate of Examples 1 to 4 and Comparative Example 1, the release film of the support sheet with the release film was peeled off, and the exposed surface of the adhesive layer of the support sheet and the exposed surface of the protective film-forming film were bonded together using a bonding device ("RAD-2700F/12" manufactured by Lintec Corporation) under conditions of laminating roll temperature: 23°C, bonding speed: 20 mm/s, and pressure: 0.3 MPa, to obtain the third laminate of Examples 1 to 4 and Comparative Example 1, which was constructed by laminating the substrate/adhesive layer/protective film-forming film/silicon wafer/backgrind tape in this order. At this time, the support sheet was also attached to a ring frame for 12-inch wafers.

Next, the backgrind tape was peeled off from the wafer/protective film-forming film/support sheet. A series of steps from the step of peeling off the light release film from the first laminate to the step of peeling off the backgrind tape were performed by an in-line process.
The transport distance of the silicon wafer from the point where attachment of the silicon wafer to the protective film-forming film was started to the point where attachment of the support sheet to the protective film-forming film was completed was 5000 mm.
The transport time of the silicon wafer from the start of attachment of the silicon wafer to the protective film-forming film to the completion of attachment of the support sheet to the protective film-forming film was 300 s. In this specification, this transport time may be simply referred to as the "transport time".
The time from the start of attachment of the silicon wafer to the protective film-forming film to the start of peeling off the backgrind tape from the silicon wafer was 7 minutes.

When the operation of attaching the wafer and support sheet to the first laminate of Example 1 as described above was repeated 30 times under the condition of a transport time of 300 s, the number of silicon wafers with protective film-forming films that could be properly held and transported was 30.
When the operation of attaching the wafer and support sheet to the first laminate of Example 1 as described above was repeated 30 times under the condition of a transport time of 170 s, the number of silicon wafers with protective film-forming films that could be properly held and transported was 30.
When the operation of attaching the wafer and support sheet to the first laminate of Example 1 as described above was repeated 30 times under the condition of a transport time of 120 s, 29 silicon wafers with protective film-forming films were able to be properly held and transported.
When the operation of attaching the wafer and support sheet to the first laminate of Example 1 as described above was repeated 30 times under the condition of a transport time of 60 s, 28 silicon wafers with protective film-forming films were able to be properly held and transported.

<Actual process peeling evaluation test>
As an actual process peeling evaluation, a backgrind tape peeling test was performed on 10 sheets of each of the third laminates of Examples 1 to 4 and Comparative Example 1 using RAD-2700F/12 with the table temperature set to 23°C.

(Peeling between protective film and silicon wafer)
In the test for 10 sheets, the number of peeled wafers between the protective film-forming film and the silicon wafer was counted. The evaluation results are shown in Tables 1 and 2 according to the following criteria.
A (pass): In the test of 10 wafers, absolutely no peeling occurred between the protective film-forming film and the silicon wafer.
B (pass): In a test of 10 wafers, peeling between the protective film and the silicon wafer was observed in one or two silicon wafers.
C (fail): In a test of 10 wafers, peeling between the protective film and the silicon wafer was observed in 3 or more silicon wafers.

(Peeling between protective film-forming film and support sheet)
In the above test, the number of peeled wafers between the protective film-forming film and the support sheet was counted. Tables 1 and 2 show the test results.

(Peeling between protective film-forming film and silicon wafer, and between protective film-forming film and support sheet)
In the above test, the number of peeled wafers between the protective film-forming film and the silicon wafer, and between the protective film-forming film and the support sheet was counted. Table 1 shows the evaluation results according to the following criteria.
A (pass): In the test of 10 wafers, there was absolutely no peeling between the protective film-forming film and the silicon wafer, or between the protective film-forming film and the support sheet.
B (Pass): In a test of 10 wafers, peeling was observed in one or two silicon wafers either between the protective film-forming film and the silicon wafer, or between the protective film-forming film and the support sheet.
C (pass): In a test of 10 wafers, peeling was observed in three or more silicon wafers either between the protective film-forming film and the silicon wafer or between the protective film-forming film and the support sheet.
D (Fail): In a test of 10 wafers, peeling was observed in 5 or more silicon wafers either between the protective film-forming film and the silicon wafer or between the protective film-forming film and the support sheet.

The protective film-forming film is applied to the mirror surface of a mirror-finished silicon wafer with a laminating roller at 70°C, and when the third laminate is manufactured by an in-line process using the kits of Examples 1 to 4 in which the 180° peel adhesion between the protective film-forming film and the silicon wafer 5 minutes after the application is 900 mN/25 mm or more, and the backgrind tape is peeled off, in all cases, there was no peeling between the protective film-forming film and the workpiece, or the risk of peeling between the protective film-forming film and the workpiece was reduced. By using the kits of Examples 1 to 4, the third laminate can be suitably manufactured by an in-line process. By manufacturing the third laminate by an in-line process, it is possible to suppress the adhesion of unintended dirt and improve the production tact time.

A support sheet was attached to the protective film-forming film with a laminating roller at 23°C, and a third laminate was produced in an in-line process using the kits of Examples 1 to 4 in which the 180° peel adhesion between the protective film-forming film and the support sheet 3 minutes after the attachment was 100 mN/25 mm or more. When the backgrind tape was peeled off, no peeling occurred between the protective film-forming film and the support sheet in any of the cases. By using the kits of Examples 1 to 4, the third laminate can be produced more suitably in an in-line process.

The kits of Examples 1 to 4 also have the advantage that they can be manufactured more cheaply than conventional composite sheets for forming protective films. Furthermore, compared to when conventional composite sheets for forming protective films are used, there is less risk of the tape meandering inside the mounter device and application failure, and it is easier to set the application position and application tension.

In the third laminate produced by the inline process using the kit of Comparative Example 1, in which the 180° peel adhesion between the protective film-forming film and the silicon wafer 5 minutes after application was less than 900 mN/25 mm, when the backgrind tape was peeled off, many wafers peeled off between the protective film-forming film and the workpiece, or between the protective film-forming film and the support sheet, and the kit of Comparative Example 1 is not suitable for use in the inline process.

The kit of the present invention can be used in a method for manufacturing a third laminate, and the third laminate can be used in the manufacture of a semiconductor device with a protective film.

1: kit, 3: composite sheet for forming protective film, 5: first laminate, 6: second laminate, 7: semiconductor chip with protective film, 8: semiconductor wafer, 8b: back surface of semiconductor wafer, 9: semiconductor chip, 10: support sheet, 10a: first surface of support sheet, 11: substrate, 11a: first surface of substrate, 12: adhesive layer, 12a: first surface of adhesive layer, 13: protective film-forming film, 13': protective film, 13a: first surface of protective film-forming film, 1 3b: second surface of protective film-forming film, 14: workpiece, 14a: circuit surface of workpiece, 14b: back surface of workpiece, 151: first release film (light release film), 152: second release film (heavy release film), 16: adhesive layer for jig, 17: back grind tape, 18: fixing jig, 19: third laminate, 19': fourth laminate, 20: semiconductor device, 21: semiconductor device with protective film, 70: punching blade, 80: suction table

Claims (14)

A kit for use in manufacturing a semiconductor device with a protective film, the kit comprising: a first laminate in which a first release film, a protective film-forming film, and a second release film are laminated in this order; and a support sheet used to support a workpiece to be protected by the protective film -forming film and the protective film-forming film ,
The protective film-forming film is attached to the mirror surface of a mirror-finished silicon wafer with a laminating roller at 70°C, and 5 minutes after the attachment, the 180° peel adhesion strength between the protective film-forming film and the silicon wafer measured at a peel speed of 100 mm/min and a temperature of 23°C is 1000 mN/25 mm or more. A kit for use in manufacturing a semiconductor device with a protective film, the kit comprising: a first laminate in which a first release film, a protective film-forming film, and a second release film are laminated in this order; and a support sheet used to support a workpiece to be protected by the protective film -forming film and the protective film-forming film ,
The protective film-forming film is applied to a mirror surface of a mirror-finished silicon wafer with a laminating roller at 70° C., and 5 minutes after the application, the 180° peel adhesion between the protective film-forming film and the silicon wafer measured at a peel speed of 100 mm/min and a temperature of 23° C. is 900 mN/25 mm or more;
A kit in which the support sheet is attached to the protective film-forming film with a laminating roller at 23°C, and 3 minutes after the attachment, the 180° peel adhesion strength between the protective film-forming film and the support sheet measured at a peel speed of 100 mm/min and a temperature of 23°C is 100 mN/25 mm or more. The kit according to claim 2, in which the protective film-forming film is applied to the mirror surface of a mirror-finished silicon wafer with a laminating roller at 70°C, and 5 minutes after the application, the 180° peel adhesion strength between the protective film-forming film and the silicon wafer measured at a peel speed of 100 mm/min and a temperature of 23°C is 1000 mN/25 mm or more. The kit according to claim 1 or 2, in which the protective film-forming film is applied to the mirror surface of a mirror-finished silicon wafer with a laminating roller at 70°C, and 5 minutes after the application, the 180° peel adhesion strength between the protective film-forming film and the silicon wafer measured at a peel speed of 100 mm/min and a temperature of 23°C is 1150 mN/25 mm or more. The protective film-forming film contains a silica filler,
The kit according to claim 1 or 2, wherein the content of the silica filler is 1 to 85 parts by mass with respect to 100 parts by mass of the total solid content constituting the protective film-forming film. The protective film-forming film contains a silica filler,
The kit according to claim 1 or 2, wherein the content of the silica filler is 5 to 66 parts by mass with respect to 100 parts by mass of the total solid content constituting the protective film-forming film. The kit according to any one of claims 1 to 6, wherein the first laminate is in a roll form. The kit according to any one of claims 1 to 7, wherein the protective film-forming film is heat-curable or energy ray-curable. The kit according to any one of claims 1 to 8, wherein the support sheet has an adhesive layer that is attached to the protective film-forming film laminated on a substrate. A method for producing a third laminate in which a workpiece, the protective film-forming film, and the support sheet are laminated in this order, the method comprising the steps of: using the kit according to any one of claims 1 to 9 in an in-line process;
peeling off a first release film of the first laminate;
A first lamination step of attaching an exposed surface of the protective film-forming film to the workpiece;
A second lamination step of attaching the support sheet to the surface opposite to the exposed surface of the protective film-forming film,
A method for manufacturing a third laminate, wherein the transport distance of the work from the start point of attachment in the first lamination process to the completion point of attachment in the second lamination process is 7000 mm or less. A method for producing a third laminate in which a workpiece, the protective film-forming film, and the support sheet are laminated in this order, the method comprising the steps of: using the kit according to any one of claims 1 to 9 in an in-line process;
peeling off a first release film of the first laminate;
A first lamination step of attaching an exposed surface of the protective film-forming film to the workpiece;
A second lamination step of attaching the support sheet to the surface opposite to the exposed surface of the protective film-forming film,
A method for manufacturing a third laminate, 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 400 s or less. A method for producing a third laminate in which a workpiece, the protective film-forming film, and the support sheet are laminated in this order, the method comprising the steps of: using the kit according to any one of claims 1 to 9 in an in-line process;
peeling off a first release film of the first laminate;
A first lamination step of attaching an exposed surface of the protective film-forming film to the workpiece;
A second lamination step of attaching the support sheet to the surface opposite to the exposed surface of the protective film-forming film,
A method for manufacturing a third laminate, in which a second laminate having the protective film-forming film attached to the workpiece is transported one sheet at a time between the first lamination step and the second lamination step. A method for producing a third laminate according to any one of claims 10 to 12, comprising the steps of: attaching a backgrind tape to a surface of the workpiece opposite to the side to which the exposed surface of the protective film-forming film is attached; and peeling off the backgrind tape from the workpiece after the second lamination step. The method for producing a third laminate according to claim 13 , wherein the backgrind tape starts to be peeled off from the work in less than 10 minutes from the start of application in the first lamination step.

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