CN114981928A

CN114981928A - Method for peeling adherend

Info

Publication number: CN114981928A
Application number: CN202180010325.6A
Authority: CN
Inventors: 篠田智则; 根本拓; 古野健太; 古贺遥
Original assignee: Lintec Corp
Current assignee: Lintec Corp
Priority date: 2020-01-27
Filing date: 2021-01-20
Publication date: 2022-08-30
Also published as: WO2021153360A1; TW202136049A; KR20220131911A; JPWO2021153360A1

Abstract

The present invention relates to a method for peeling an adherend, a method for manufacturing a semiconductor chip including a step of performing the peeling method, and a method for manufacturing a semiconductor device including a step of performing the peeling method, the method for peeling an adherend including: step (S1): a step of bonding a plurality of adherends to the adhesive layer (X1); and a step (S2): a step of sublimating at least a part of the adhesive layer (X1) in a region where a part of the adherends is bonded, thereby generating gas and reducing the adhesion between the part of adherends and the adhesive layer (X1).

Description

Method for peeling adherend

Technical Field

The present invention relates to a method for peeling an adherend.

Background

The pressure-sensitive adhesive sheet is used not only for the purpose of fixing a member semi-permanently, but also for the purpose of temporarily fixing a building material, an interior material, an optical material, an electronic component, or the like when they are processed.

Such pressure-sensitive adhesive sheets for temporary fixation use are required to satisfy both of adhesiveness to an adherend during use (during temporary fixation) and releasability from the adherend after use.

However, as a method for peeling an adherend from a pressure-sensitive adhesive sheet, for example, a method using a heat-peelable pressure-sensitive adhesive sheet in which a pressure-sensitive adhesive layer containing thermally expandable fine particles is provided on at least one surface of a substrate is known (see patent document 1 and the like). In this method, when an adherend bonded to a pressure-sensitive adhesive sheet is peeled off, the adherend is peeled off from the pressure-sensitive adhesive sheet by heating to expand the thermally expandable fine particles of the pressure-sensitive adhesive layer and reduce the contact area between the adherend and the pressure-sensitive adhesive layer, thereby reducing the adhesive strength between the pressure-sensitive adhesive layer and the adherend (see, for example, patent document 1).

Documents of the prior art

Patent document

Patent document 1: japanese unexamined patent publication No. 2001-131507

Disclosure of Invention

Problems to be solved by the invention

The heat-peelable pressure-sensitive adhesive sheet described in patent document 1 is generally used in such a manner that the entire surface of the pressure-sensitive adhesive layer is subjected to heat treatment so that the adhesive strength between the pressure-sensitive adhesive layer and an adherend is reduced over the entire surface of the pressure-sensitive adhesive layer. That is, the adherend is used in such a manner that the adherend is peeled off from the adhesive layer at a time.

However, there are cases where it is not desired to peel the adherend from the adhesive layer at once, but only a part of the adherend is selectively peeled. For example, in the case where the adherend is a semiconductor chip with a protective film, there are cases where only a part of the semiconductor chips with a protective film among a plurality of semiconductor chips with a protective film attached to the adhesive layer is subjected to a subsequent step. In such a case, if the adhesive force between the adhesive layer and the semiconductor chip with the protective film is reduced over the entire surface of the adhesive layer, the semiconductor chip with the protective film remaining without being picked up may be displaced or peeled from the adhesive layer due to vibration or the like generated when only a part of the semiconductor chip with the protective film is selectively picked up and moved. The same problem may occur not only in a semiconductor chip with a protective film but also in various adherends.

Accordingly, an object of the present invention is to provide a method for peeling an adherend, which can selectively reduce the adhesion to an adhesive layer only for a part of the plurality of adherends adhered to the adhesive layer.

Means for solving the problems

As a result of intensive studies, the present inventors have found that the above-mentioned problems can be solved by sublimating at least a part of the pressure-sensitive adhesive layer in the region where a part of the adherend to be peeled off is adhered to generate a gas to lower the adhesion between the part of the adherend and the pressure-sensitive adhesive layer, and have further made various studies to complete the present invention.

That is, the present invention relates to the following [1] to [9 ].

[1] A method for peeling an adherend, comprising the following steps (S1) and (S2).

Step (S1): a step of bonding a plurality of adherends to the adhesive layer (X1);

step (S2): and a step of sublimating at least a part of the pressure-sensitive adhesive layer (X1) in a region where a part of the plurality of adherends is bonded to generate a gas, thereby reducing the adhesion between the part of adherends and the pressure-sensitive adhesive layer (X1).

[2] The peeling method according to the above [1], wherein,

the adhesive layer (X1) is made to be an adhesive layer capable of absorbing laser light,

the step (S2) is performed by irradiating the laser beam onto at least a part of the pressure-sensitive adhesive layer (X1) in the region to which the adherend is partially attached.

[3] The peeling method according to the above [1] or [2], wherein,

the following step (SP1) is performed before the step (S2) or after the step (S2), and the following step (SP2) is performed after the step (SP1) and after the step (S2).

Step (SP 1): laminating the pressure-sensitive adhesive layer (Z1) of a transfer sheet (Z) having a pressure-sensitive adhesive layer (Z1) to the surface of the plurality of adherends opposite to the surface to be laminated with the pressure-sensitive adhesive layer (X1), and laminating the pressure-sensitive adhesive layer (X1) and the transfer sheet (Z) with the plurality of adherends interposed therebetween;

step (SP 2): separating the transfer sheet (Z) from the pressure-sensitive adhesive layer (X1), and peeling off only the part of the adherend from the pressure-sensitive adhesive layer (X1) to transfer the part of the adherend to the transfer sheet (Z).

[4] The peeling method according to any one of the above [1] to [3], wherein,

in the step (S1), a psa sheet (X) having the psa layer (X1) is used.

[5] The peeling method according to any one of the above [1] to [4], wherein,

the adherend is a semiconductor chip.

[6] The peeling method according to any one of the above [1] to [5], wherein,

the adherend is a semiconductor chip with a protective film.

[7] The peeling method according to the above [5] or [6], wherein,

the pressure-sensitive adhesive sheet (X) is a dicing tape.

[8] A method of manufacturing a semiconductor chip, comprising: a step of carrying out the method according to any one of the above [5] to [7 ].

[9] A method of manufacturing a semiconductor device, comprising: a step of carrying out the method according to any one of the above [5] to [7 ].

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to provide a method for peeling an adherend, which can selectively reduce the adhesion between the adherend and an adhesive layer only for some of a plurality of adherends attached to the adhesive layer.

Drawings

FIG. 1 is a view showing an example of the step (S1) of the peeling method of the present invention, wherein (A) is a plan view, and (B-1) and (B-2) are schematic sectional views.

Fig. 2 is a schematic cross-sectional view showing an example of the step (S2) of the peeling method of the present invention.

Fig. 3 is a schematic cross-sectional view showing a portion surrounded by a broken line in fig. 2 enlarged and showing the passage of the decrease in the adhesive force.

Fig. 4 is a diagram showing an example of the step (S1) of the peeling method of the present invention in the case where a semiconductor chip with a protective film is used as an adherend, where (a) is a plan view and (B) is a schematic sectional view.

Fig. 5 is a schematic cross-sectional view showing an example of steps (S1-1) to (S1-2) of the peeling method according to one embodiment of the present invention, in the case where a semiconductor chip with a protective film is used as an adherend.

Fig. 6 is a schematic cross-sectional view showing an example of the step (S2) of the peeling method of the present invention for the case where a semiconductor chip with a protective film is used as an adherend.

Fig. 7 is a schematic cross-sectional view showing a portion surrounded by a broken line in fig. 6 enlarged and showing the passage of the decrease in the adhesive force.

Fig. 8 is a schematic cross-sectional view showing an example of steps (SP1) to (SP2) of the peeling method according to one embodiment of the present invention.

Description of the symbols

1. 1a adherend

2 semiconductor wafer

10 semiconductor wafer with protective film

11. 11a semiconductor chip with protective film

12 semiconductor chip

13 protective film

20 gaps and cut portions between adherends

30 laser irradiation device

X-shaped adhesive sheet

X1 adhesive layer

Y base material

Z transfer sheet

Z1 adhesive layer

Y' base material

Detailed Description

In the present invention, the "active ingredient" refers to a component other than the diluting solvent among the components contained in the target composition.

The weight average molecular weight (Mw) is a value in terms of standard polystyrene measured by a Gel Permeation Chromatography (GPC) method, and specifically is a value measured by the method described in examples.

In addition, "(meth) acrylic acid" means both "acrylic acid" and "methacrylic acid", and other similar terms are also used.

In addition, regarding a preferable numerical range (for example, a range of a content or the like), lower limit values and upper limit values described in a hierarchical manner may be independently combined. For example, according to the description of "preferably 10 to 90, more preferably 30 to 60", the "preferable lower limit value (10)" and the "more preferable upper limit value (60)" can be combined to obtain "10 to 60".

[ method for peeling adherend ]

The method for peeling off an adherend of the present invention includes the following step (S1) and the following step (S2).

In the following description, the method for peeling off an adherend according to the invention is also simply referred to as "the method for peeling off according to the invention".

The method for peeling off an adherend according to an embodiment of the present invention is also simply referred to as "the method for peeling off an adherend according to an embodiment of the present invention".

The step (S1) is also referred to as a "preparation step".

The step (S2) is also referred to as a "adhesive strength reducing step".

The following describes the step (S1) and the step (S2).

< step (S1): preparation Process >

In step (S1), as shown in fig. 1, a pressure-sensitive adhesive sheet (X) is prepared in which a plurality of adherends 1 are bonded to a pressure-sensitive adhesive layer (X1).

The adherend 1 is not particularly limited, and examples thereof include: and a semiconductor chip, a semiconductor chip with a protective film, a semiconductor chip with a Die Attach Film (DAF), a glass substrate, a sapphire substrate, a compound semiconductor substrate, and the like. The adherend 1 is not necessarily limited to a singulated article, and may be various wafers, various substrates, and the like that are not singulated.

Here, in fig. 1 (B-1), a plurality of adherends 1 are bonded to the pressure-sensitive adhesive layer (X1) of the pressure-sensitive adhesive sheet (X) in which the pressure-sensitive adhesive layer (X1) is laminated on one surface of the substrate (Y), but this is merely an example, and a plurality of adherends 1 may be bonded to the pressure-sensitive adhesive layer (X1) having no substrate (Y) as shown in fig. 1 (B-2). The pressure-sensitive adhesive layer (X1) having no base material (Y) can be used, for example, by bonding and fixing one surface of the plurality of adherends 1 opposite to the bonding surface to a hard substrate or the like.

The structure of the pressure-sensitive adhesive sheet (X) is not limited to the structure shown in fig. 1 (B-1), and for example, a pressure-sensitive adhesive layer (X1) may be provided on both surfaces of the substrate (Y) (in this case, the pressure-sensitive adhesive layer (X1) on either side may be a pressure-sensitive adhesive layer (X2) described later). Further, a release material may be provided on the adhesive surface of the adhesive layer (X1), and the release material may be released to expose the adhesive surface of the adhesive layer (X1) immediately before the plurality of adherends 1 are bonded to the adhesive layer (X1).

< step (S2): adhesive force reducing step >

In the step (S2), at least a part of the adhesive layer (X1) in the region where a part of the plurality of adherends is bonded is sublimated to generate gas, thereby reducing the adhesion between the part of the adherends and the adhesive layer (X1).

The present inventors have conceived a method of sublimating at least a part of the pressure-sensitive adhesive layer (X1) in a region where a part of an adherend to be peeled off is stuck to generate a gas as a method of selectively reducing the adhesion between a part of the plurality of adherends and the pressure-sensitive adhesive layer (X1), and have completed the present invention.

The method of sublimating a part of the adhesive layer (X1) to generate gas is not particularly limited, and for example, it is preferable to use an adhesive layer (X1) capable of absorbing laser light and irradiate laser light on at least a part of the adhesive layer (X1) in a region where an adherend is partially attached.

Fig. 2 shows an embodiment of the process (S2) using a laser. Fig. 3 is an enlarged view of a portion surrounded by a broken line in fig. 2, schematically showing a case where the adhesive strength between a part of the plurality of adherends and the adhesive layer (X1) is reduced.

In the step (S2) using a laser beam, it is preferable that the laser beam is irradiated from the surface of the pressure-sensitive adhesive layer (X1) opposite to the surface to be bonded with the adherend, and that at least a part of the pressure-sensitive adhesive layer (X1) in the region to which a part of the adherend is bonded is irradiated with the laser beam. In the case of using the pressure-sensitive adhesive sheet (X) having the pressure-sensitive adhesive layer (X1), for example, as shown in fig. 2 and 3, it is preferable that the laser light L generated by the laser irradiation device 30 is made incident from the substrate (Y) side of the pressure-sensitive adhesive sheet (X) and is irradiated to at least a part of the pressure-sensitive adhesive layer (X1) in the region where a part of the adherend 1a is bonded. This causes sublimation gas to be generated by ablation of a part of the adhesive layer (X1), and the contact area between a part of the adherend 1a and the adhesive layer (X1) is reduced around the irradiated portion of the laser beam L. Further, as shown in fig. 3B, the irradiation area of the laser light L to the adhesive layer (X1) is enlarged to ablate the adhesive layer (X1) over a wide range and generate sublimation gas, thereby further reducing the contact area between a part of the adherend 1a and the adhesive layer (X1). This reduces the adhesion between part of the adherend 1a and the pressure-sensitive adhesive layer (X1).

Even if the sublimation gas leaks around a part of the adherend 1a, the leaked sublimation gas is released into the gap 20 between the adherends. Therefore, the adhesive strength of the adherend 1 that is not intended to be peeled off around a part of the adherend 1a can be prevented from being lowered.

In addition, since the step (S2) using a laser beam does not involve a step of reducing the adhesion between the adherend and the pressure-sensitive adhesive layer (X1) by heat treatment, deterioration, warpage, and the like of the adherend due to heating can be suppressed. Further, it is preferable that most of the irradiated laser light L is absorbed in the pressure-sensitive adhesive layer (X1). In this case, the sublimation efficiency of the pressure-sensitive adhesive layer (X1) can be improved, and damage to the adherend by the laser beam can be suppressed.

The laser irradiation device 30 is not particularly limited as long as it can irradiate a laser beam that can cause sublimation gas to be generated from the adhesive layer (X1), and for example, a laser irradiation device for performing laser marking on a protective film of a semiconductor chip with a protective film or the like can be used.

Examples of such a laser irradiation device include CSM3000M (green solid-state laser, wavelength: 532nm) manufactured by EOTechnics, but the laser irradiation device is not necessarily limited to this, and various devices capable of emitting laser light that can be absorbed by the adhesive layer (X1) can be used.

The irradiation condition of the laser light is not particularly limited as long as the pressure-sensitive adhesive layer (X1) can absorb the laser light, but the frequency is preferably 10,000Hz to 30,000Hz, for example, from the viewpoint of more efficiently peeling off a part of the adherend. The beam diameter of the laser beam is preferably 10 to 100 μm, more preferably 20 to 40 μm. The output power of the laser is preferably 0.1W to 1.0W. The scanning speed of the laser is 50-200 mm/s.

In addition, the laser irradiation to the adhesive layer (X1) can reduce the adhesive force with the adhesive layer (X1) by irradiating at least a part of the adhesive layer (X1) in the region where the adherend to be peeled is adhered, however, from the viewpoint of further reducing the adhesive strength, the laser irradiation to the adhesive layer (X1) in the region to which the adherend requiring peeling is bonded is preferably performed to a region of 50% or more, more preferably to a region of 60% or more, further preferably to a region of 70% or more, further preferably to a region of 80% or more, further preferably to a region of 90% or more, and further preferably to a region of 100% or more of the entire surface of the adhesive layer (X1) in the region to which the adherend requiring peeling is bonded (that is, to the entire surface of the adhesive layer (X1) in the region to which the adherend requiring peeling is bonded).

It is preferable that the laser irradiation to the region to which the pressure-sensitive adhesive layer (X1) of the adherend is bonded is not biased to partial region irradiation but is dispersed and irradiated over a plurality of regions. For example, by irradiating the edge portion and the central portion of the region where the adhesive layer (X1) of the adherend is bonded with laser light, the contact area between the adherend and the adhesive layer (X1) is easily reduced effectively, and therefore the adhesion between the adherend and the adhesive layer (X1) is easily reduced effectively.

As described above, the laser irradiation to the pressure-sensitive adhesive layer (X1) is preferably performed from the surface of the pressure-sensitive adhesive layer (X1) opposite to the bonding surface with the plurality of adherends toward the adherends. When the adhesive sheet (X) is used, it is preferably carried out from the substrate (Y) side toward the adherend. Preferably, the adhesive layer (X1) is provided on or near the surface of the adhesive layer (X1) to be adhered. Further, the laser beam is preferably adjusted so as to be irradiated to the bonding surface of the pressure-sensitive adhesive layer (X1) to the adherend or the vicinity thereof. Here, the vicinity of the bonding surface of the adhesive layer (X1) to the adherend indicates a position within 10 μm of the bonding surface.

[ embodiment of the peeling method of the present invention in the case of using a semiconductor chip with a protective film ]

Next, in order to more specifically describe the peeling method of the present invention, a case of using a semiconductor chip with a protective film as an adherend will be described in detail as an example.

< step (S1) when the semiconductor chip with the protective film is used: preparation Process >

In the step (S1), as shown in fig. 4, the plurality of semiconductor chips 11 with the protective film are bonded to the pressure-sensitive adhesive layer with the protective film 13 side as a bonding surface (X1). In fig. 4, a plurality of semiconductor chips 11 with a protective film are bonded to the adhesive layer (X1) of the adhesive sheet (X) in which the adhesive layer (X1) is laminated on one surface of the base material (Y), but this is merely an example, and a plurality of semiconductor chips 11 with a protective film may be bonded to the adhesive layer (X1) without the base material (Y). The pressure-sensitive adhesive layer (X1) not having the base material (Y) can be used, for example, by bonding and fixing one surface of the plurality of semiconductor chips 11 with the protective film, which is opposite to the bonding surface, to a hard substrate or the like.

As described above, the pressure-sensitive adhesive sheet (X) may have the pressure-sensitive adhesive layer (X1) on both surfaces of the substrate (Y), or may have a release agent on the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer (X1).

The semiconductor chip with protective film 11 may be constituted by a semiconductor chip 12 and a protective film 13. The protective film 13 is formed on a surface of the semiconductor chip 12 opposite to the circuit surface 12a, i.e., the back surface 12b of the semiconductor chip 12.

The thickness of the semiconductor chip 12 is not particularly limited, but is usually 3 μm to 500. mu.m.

The thickness of the protective film 13 is not particularly limited, but is preferably 0.05 μm to 200. mu.m.

The size of the semiconductor chip 12 is not particularly limited, but is usually 5 μm to 15mm in the longitudinal direction and 5 μm to 15mm in the lateral direction.

< step (S1-1) and step (S1-2) >

Here, in the preparation step of the step (S1) in the case of using the semiconductor chip with a protective film, the plurality of semiconductor chips 11 with a protective film may be bonded to the pressure-sensitive adhesive layer (X1) as described above, and the order of performing the step (S1) is not limited, but from the viewpoint of efficiently performing the present invention including the singulation step of the semiconductor wafer with a protective film, it is preferable that the step (S1) in the peeling method according to one embodiment of the present invention includes the following steps (S1-1) to (S1-2) in this order.

Step (S1-1): bonding the semiconductor wafer with the protective film to an adhesive layer (X1) with the protective film side as a bonding surface;

step (S1-2): and dicing the semiconductor wafer with the protective film to obtain the plurality of semiconductor chips with the protective film.

(step (S1-1))

In the step (S1-1), as shown in fig. 5, the semiconductor wafer 10 with the protective film is bonded to the pressure-sensitive adhesive layer with the protective film 13 side as the bonding surface (X1). In fig. 5, the semiconductor wafer 10 with the protective film is bonded to the pressure-sensitive adhesive layer (X1) of the pressure-sensitive adhesive sheet (X) in which the pressure-sensitive adhesive layer (X1) is laminated on one surface of the substrate (Y), but this is merely an example, and the semiconductor wafer 10 with the protective film may be bonded to the pressure-sensitive adhesive layer (X1) without the substrate (Y) as described above.

The semiconductor wafer with a protective film 10 is composed of a semiconductor wafer 2 and a protective film 13. The protective film 13 is formed on the surface of the semiconductor wafer 2 opposite to the circuit surface 2a, i.e., the back surface 2b of the semiconductor wafer 2.

Examples of the semiconductor wafer 2 include: silicon wafers, silicon carbide wafers, compound semiconductor wafers, glass wafers, sapphire wafers, and the like. The back surface of the semiconductor wafer 2 may be ground as appropriate, and the thickness may be about 3 μm to 500 μm.

The shape of the semiconductor wafer 2 is not limited to a circular shape, and may be a square shape such as a square shape or a rectangular shape.

The thickness of the protective film 13 is preferably 0.05 μm to 200 μm.

(step (S1-2))

In the step (S1-2), the semiconductor wafer with protective film 10 is diced as shown in fig. 5 to obtain a plurality of semiconductor chips with protective film 11.

The cutting method is not particularly limited, and known methods such as blade cutting and laser cutting can be used. The dicing may be performed by providing the notch 20 so as to penetrate the semiconductor wafer 2 and the protective film 13, for example.

After dicing, a spreading process may be performed to increase the interval between the semiconductor chips 11 with the protective film (the width of the cut portions 20).

(method for manufacturing semiconductor wafer with protective film)

The method for producing the semiconductor wafer with the protective film used in the step (S1-1) is not particularly limited, but the semiconductor wafer with the protective film is preferably obtained by bonding the protective film forming film to the semiconductor wafer and then curing the protective film forming film, from the viewpoint of making the thickness of the protective film uniform and making the coating property of the protective film to the back surface of the semiconductor wafer excellent.

The curing of the protective film forming film may be performed by any of thermal curing and curing by irradiation with an energy ray, depending on the kind of the curable component contained in the protective film forming film.

In the present specification, the "energy ray" means a ray having an energy quantum in an electromagnetic wave or a charged particle beam, and examples thereof include an ultraviolet ray, an electron beam, and the like, and preferably an ultraviolet ray.

As conditions for the thermal curing, the curing temperature is preferably 100 to 170 ℃ and the curing time is preferably 1 to 3 hours.

The conditions for curing by irradiation with an energy ray may be appropriately determined depending on the type of the energy ray used. For example, when ultraviolet light is used, the illuminance is preferably 170mW/cm ² ～250mW/cm ² The light quantity is preferably 600mJ/cm ² ～1,000mJ/cm ² 。

The curing of the protective film forming film may be performed before the semiconductor wafer to which the protective film forming film is bonded to the adhesive layer (X1), or after the semiconductor wafer to which the protective film forming film is bonded to the adhesive layer (X1).

Here, in the case where the semiconductor wafer to which the protective film forming film is bonded to the adhesive layer (X1) and then the protective film forming film is cured, it is preferable to bond the protective film forming film and the adhesive layer (X1) to the back surface 2b of the semiconductor wafer at one time from the viewpoint of simplification of the process. Specifically, it is preferable to use a protective film-forming laminate in which a protective film-forming film is laminated on the pressure-sensitive adhesive layer (X1) of the pressure-sensitive adhesive sheet (X) having the pressure-sensitive adhesive layer (X1), and cure the protective film-forming film after the protective film-forming film side of the protective film-forming laminate is bonded to the back surface of the semiconductor wafer.

< step (S2) when the semiconductor chip with the protective film is used: adhesive force reducing step >

In the step (S2) of using the semiconductor chip with the protective film, at least a part of the adhesive layer (X1) in the region of the semiconductor chip with a part of the protective film among the plurality of semiconductor chips with the protective film is sublimated to generate gas, thereby reducing the adhesion between the semiconductor chip with a part of the protective film and the adhesive layer (X1).

The method of sublimating a part of the protective film to generate gas is not particularly limited, and it is preferable to irradiate at least a part of the protective film of the semiconductor chip partially provided with the protective film with laser light using, for example, a protective film capable of absorbing laser light.

Fig. 6 shows an embodiment of the process (S2) using a laser. Fig. 7 is an enlarged view of a portion surrounded by a broken line in fig. 6, schematically showing a case where the adhesive strength between a part of the semiconductor chip with a protective film and the adhesive layer (X1) is reduced among the plurality of semiconductor chips with a protective film.

In the step (S2) of using a laser beam, the adhesive layer (X1) is preferably irradiated with a laser beam from the side of the adhesive layer (X1) opposite to the bonding surfaces of the plurality of semiconductor chips with the protective film. In the case of using the adhesive sheet (X) having the adhesive layer (X1), for example, as shown in fig. 6 and 7, it is preferable that the laser light L generated by the laser irradiation device 30 is made incident from the substrate (Y) side of the adhesive sheet (X) and is irradiated to at least a part of the adhesive layer (X1) in the region where the semiconductor chip 11a with a part of the protective film is bonded. This causes sublimation gas to be generated by ablation of a part of the adhesive layer (X1), and the contact area between a part of the semiconductor chip 11a with the protective film and the adhesive layer (X1) is reduced around the irradiated portion of the laser beam L. Further, the irradiation region of the laser beam L to the adhesive layer (X1) is enlarged to ablate the adhesive layer (X1) in a wide range and generate sublimation gas, thereby further reducing the contact area between a part of the semiconductor chip 11a with the protective film and the adhesive layer (X1). This reduces the adhesion between the semiconductor chip 11a partially provided with the protective film and the pressure-sensitive adhesive layer (X1).

Even if the sublimation gas leaks around a part of the semiconductor chip 11a with the protective film, the leaked sublimation gas is released to the cut portion 20. Therefore, the adhesive strength of the semiconductor chip with a protective film 11, which is not intended to be peeled off, around a part of the semiconductor chip with a protective film 11a can be prevented from being lowered.

The laser irradiation device 30 may be the same device as the aforementioned device.

The irradiation conditions of the laser beam and the like are as described above.

Next, the following description will be made of the structure of the adhesive sheet (X) and the protective film forming film used in the peeling method of the present invention.

[ adhesive sheet (X) ]

The adhesive sheet (X) has a laminated structure of a substrate (Y) and an adhesive layer (X1).

The pressure-sensitive adhesive sheet (X) shown in fig. 1 to 8 is provided in the form of a pressure-sensitive adhesive layer (X1) on one surface of the substrate (Y), but is not limited thereto, and may be provided in the form of a double-sided pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer (X2) on the other surface of the substrate (Y).

In the peeling method according to one embodiment of the present invention, the pressure-sensitive adhesive sheet (X) is preferably a dicing tape. The layers that the pressure-sensitive adhesive sheet (X) can have are explained below.

< substrate (Y) >

The substrate (Y) of the adhesive sheet (X) functions as a support for supporting the adhesive layer (X1), and may be made of, for example, a resin film having laser transparency and made of a resin-based material as a main material.

Specific examples of the resin film include: polyolefin-based films such as polyethylene films including low-density polyethylene (LDPE) films, linear low-density polyethylene (LLDPE) films, and high-density polyethylene (HDPE) films, polypropylene films, polybutylene films, polybutadiene films, polymethylpentene films, ethylene-norbornene copolymer films, and norbornene resin films; ethylene copolymer films such as ethylene-vinyl acetate copolymer films, ethylene- (meth) acrylic acid copolymer films, and ethylene- (meth) acrylate copolymer films; polyvinyl chloride films such as polyvinyl chloride films and vinyl chloride copolymer films; polyester films such as polyethylene terephthalate films and polybutylene terephthalate films; a polyurethane film; a polyimide film; a polystyrene film; a polycarbonate film; fluororesin films, and the like. Further, modified films such as crosslinked films and ionomer films obtained by crosslinking resins forming these films may also be used.

One of these resin films may be used alone as the substrate (Y), or a laminated film obtained by combining two or more of them may be used.

Here, from the viewpoint of versatility, high strength, easy prevention of warpage, heat resistance, and improvement of laser light transmittance, the resin film is preferably a polyethylene film such as a Low Density Polyethylene (LDPE) film, a Linear Low Density Polyethylene (LLDPE) film, and a High Density Polyethylene (HDPE) film, a polyester film such as a polyethylene terephthalate film and polybutylene terephthalate film, or a polypropylene film. Specifically, the resin film is preferably a single-layer film having one or more layers selected from a polyethylene film, a polyester film, and a polypropylene film, or a laminate film obtained by laminating two or more layers.

From the viewpoint of easily ensuring high light transmittance to light of a desired wavelength, it is preferable to improve the smoothness of the 1 st surface (the surface opposite to the surface on which the pressure-sensitive adhesive layer (X1) is formed) of the base material (Y). Specifically, the arithmetic average roughness Ra of the 1 st surface of the base material (Y) is preferably 0.01 to 0.8. mu.m. The arithmetic average roughness Ra is a value measured in accordance with JIS B0601: 1994.

The substrate (Y) may contain a colorant, but when a laser is used in the adhesive strength reducing step in the step (S2), the content of the colorant that absorbs the laser is preferably small from the viewpoint of obtaining a substrate having more excellent laser light transmittance. Specifically, the content of the laser light absorbing colorant is preferably less than 0.1% by mass, more preferably less than 0.01% by mass, even more preferably less than 0.001% by mass, and even more preferably no colorant based on the total amount of the base material (Y).

The thickness of the substrate (Y) is not particularly limited, but is preferably in the range of 20 to 450 μm, more preferably 25 to 400 μm.

< adhesive layer (X1) >

The pressure-sensitive adhesive layer (X1) may contain a pressure-sensitive adhesive resin, and may contain a pressure-sensitive adhesive additive such as a crosslinking agent, a tackifier, a polymerizable compound, or a polymerization initiator, as necessary.

The adhesive layer (X1) may be formed of an adhesive composition containing an adhesive resin.

Hereinafter, each component contained in the pressure-sensitive adhesive composition as a material for forming the pressure-sensitive adhesive layer (X1) will be described.

(adhesive resin)

The adhesive resin is preferably a polymer having adhesive properties and a weight average molecular weight (Mw) of 1 ten thousand or more, which is obtained by using the resin alone.

The weight average molecular weight (Mw) of the pressure-sensitive adhesive resin is more preferably 1 to 200 ten thousand, still more preferably 2 to 150 ten thousand, and still more preferably 3 to 100 ten thousand, from the viewpoint of improving the pressure-sensitive adhesive force.

The glass transition temperature (Tg) of the adhesive resin is preferably-60 ℃ to-10 ℃, more preferably-50 ℃ to-20 ℃.

Examples of the adhesive resin include: rubber-based resins such as polyisobutylene-based resins, acrylic-based resins, urethane-based resins, polyester-based resins, olefin-based resins, silicone-based resins, and polyvinyl ether-based resins.

These adhesive resins may be used alone or in combination of two or more.

When the adhesive resin is a copolymer having two or more kinds of structural units, the form of the copolymer is not particularly limited, and may be any of a block copolymer, a random copolymer, an alternating copolymer, and a graft copolymer.

The adhesive resin may be an energy ray-curable adhesive resin having a polymerizable functional group introduced into a side chain thereof.

Examples of the polymerizable functional group include a (meth) acryloyl group and a vinyl group.

The energy ray includes ultraviolet rays and electron beams, and preferably ultraviolet rays.

The content of the adhesive resin is preferably 30 to 99.99% by mass, more preferably 40 to 99.95% by mass, even more preferably 50 to 99.90% by mass, even more preferably 55 to 99.80% by mass, and even more preferably 60 to 99.50% by mass, based on the total amount (100% by mass) of the active ingredients in the adhesive composition.

In the following description of the present specification, the "content of each component relative to the total amount of active ingredients of the pressure-sensitive adhesive composition" means the same as the "content of each component in the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition".

Here, the adhesive resin preferably contains an acrylic resin from the viewpoint of exhibiting excellent adhesive force and also suppressing a phenomenon in which cutting water penetrates between the adhesive layer (X1) and the protective film at the time of dicing.

The content of the acrylic resin in the adhesive resin is preferably 30 to 100% by mass, more preferably 50 to 100% by mass, even more preferably 70 to 100% by mass, and even more preferably 85 to 100% by mass, based on the total amount (100% by mass) of the adhesive resin contained in the adhesive composition.

(acrylic resin)

As the acrylic resin that can be used as the adhesive resin, for example: a polymer containing a structural unit derived from an alkyl (meth) acrylate having a linear or branched alkyl group, a polymer containing a structural unit derived from a (meth) acrylate having a cyclic structure, or the like.

The weight average molecular weight (Mw) of the acrylic resin is preferably 10 to 150 ten thousand, more preferably 20 to 130 ten thousand, and further preferably 35 to 120 ten thousand.

The acrylic resin is more preferably an acrylic copolymer (a1) having a structural unit (a1) derived from an alkyl (meth) acrylate (a1 ') (hereinafter, also referred to as "monomer (a 1')") and a structural unit (a2) derived from a functional group-containing monomer (a2 ') (hereinafter, also referred to as "monomer (a 2')").

The number of carbon atoms of the alkyl group of the monomer (a 1') is preferably 1 to 24, more preferably 1 to 12, even more preferably 2 to 10, and even more preferably 4 to 8, from the viewpoint of improving the adhesive properties and from the viewpoint of suppressing the phenomenon that cutting water penetrates between the adhesive layer (X1) and the protective film during dicing.

The alkyl group of the monomer (a 1') may be a straight-chain alkyl group or a branched-chain alkyl group.

Examples of the monomer (a 1') include: methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate, and the like.

These monomers (a 1') may be used singly or in combination.

The monomer (a 1') is preferably at least one member selected from the group consisting of methyl (meth) acrylate, butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate, and more preferably at least one member selected from the group consisting of methyl (meth) acrylate and butyl (meth) acrylate.

The content of the structural unit (a1) is preferably 50 to 99.9 mass%, more preferably 60 to 99.0 mass%, even more preferably 70 to 97.0 mass%, and even more preferably 80 to 95.0 mass% based on the total structural units (100 mass%) of the acrylic copolymer (a 1).

Examples of the functional group of the monomer (a 2') include: hydroxyl, carboxyl, amino, and epoxy groups.

That is, examples of the monomer (a 2') include: hydroxyl group-containing monomers, carboxyl group-containing monomers, amino group-containing monomers, epoxy group-containing monomers, and the like.

These monomers (a 2') may be used alone or in combination of two or more.

Among these monomers, the monomer (a 2') is preferably a hydroxyl group-containing monomer and a carboxyl group-containing monomer, and more preferably a hydroxyl group-containing monomer.

Examples of the hydroxyl group-containing monomer include: hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate; unsaturated alcohols such as vinyl alcohol and allyl alcohol.

Among these hydroxyl group-containing monomers, 2-hydroxyethyl (meth) acrylate is preferable.

Examples of the carboxyl group-containing monomer include: ethylenically unsaturated monocarboxylic acids such as (meth) acrylic acid and crotonic acid; ethylenically unsaturated dicarboxylic acids such as fumaric acid, itaconic acid, maleic acid, and citraconic acid, and anhydrides thereof, 2- (acryloyloxy) ethyl succinate, and 2-carboxyethyl (meth) acrylate.

The content of the structural unit (a2) is preferably 0.1 to 40% by mass, more preferably 0.5 to 35% by mass, even more preferably 1.0 to 30% by mass, even more preferably 3.0 to 25% by mass, based on the total structural units (100% by mass) of the acrylic copolymer (a 1).

The acrylic copolymer (a1) may further have a structural unit (a3) derived from a monomer (a3 ') other than the monomers (a1 ') and (a2 ').

In the acrylic copolymer (a1), the content of the structural units (a1) and (a2) is preferably 70 to 100% by mass, more preferably 80 to 100% by mass, even more preferably 90 to 100% by mass, and even more preferably 95 to 100% by mass, based on the total structural units (100% by mass) of the acrylic copolymer (a 1).

Examples of the monomer (a 3') include: olefins such as ethylene, propylene and isobutylene; halogenated olefins such as vinyl chloride and vinylidene chloride; diene monomers such as butadiene, isoprene and chloroprene; (meth) acrylates having a cyclic structure such as cyclohexyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, and imide (meth) acrylate; styrene, α -methylstyrene, vinyltoluene, vinyl formate, vinyl acetate, acrylonitrile, (meth) acrylamide, (meth) acrylonitrile, (meth) acryloylmorpholine, N-vinylpyrrolidone and the like.

The acrylic copolymer (a1) may be an energy ray-curable acrylic copolymer having a polymerizable functional group introduced into a side chain thereof.

The polymerizable functional group can be introduced by reacting the acrylic copolymer having the structural units (a1) and (a2) with a compound having a polymerizable functional group and a substituent capable of bonding to the functional group of the structural unit (a2) of the acrylic copolymer.

Examples of the above-mentioned compounds include: (meth) acryloyloxyethyl isocyanate, (meth) acryloyl isocyanate, glycidyl (meth) acrylate, and the like.

(crosslinking agent)

The adhesive composition preferably further contains a crosslinking agent.

This crosslinking agent reacts with the adhesive resin having a functional group as in the above-mentioned acrylic copolymer (a1), and crosslinks the adhesive resins with the functional group as a crosslinking origin.

Examples of the crosslinking agent include: isocyanate crosslinking agents, epoxy crosslinking agents, aziridine crosslinking agents, metal chelate crosslinking agents, and the like.

These crosslinking agents may be used alone or in combination of two or more.

Among these crosslinking agents, isocyanate-based crosslinking agents are preferable from the viewpoint of improving cohesive force to improve adhesive force, acquisition easiness, and the like.

The content of the crosslinking agent may be appropriately adjusted depending on the number of functional groups contained in the adhesive resin, but is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 7 parts by mass, and still more preferably 0.05 to 5 parts by mass, based on 100 parts by mass of the adhesive resin having functional groups.

(tackifier)

In the present embodiment, the pressure-sensitive adhesive composition may further contain a tackifier from the viewpoint of further improving the adhesive strength.

In the present specification, the "tackifier" is an oligomer having a weight average molecular weight (Mw) of less than 1 ten thousand among components for increasing the adhesive force of the adhesive resin in an auxiliary manner, and is a component different from the adhesive resin.

The thickener has a weight average molecular weight (Mw) of preferably 400 or more and less than 10,000, more preferably 500 to 8,000, and still more preferably 800 to 5,000.

Examples of the tackifier include: rosin-based resins, terpene-based resins, styrene-based resins, C5-based petroleum resins obtained by copolymerizing pentene, isoprene, piperine produced by pyrolysis of naphtha and C5 fractions such as 1, 3-pentadiene, C9-based petroleum resins obtained by copolymerizing indene produced by pyrolysis of naphtha and C9 fractions such as vinyl toluene, hydrogenated resins obtained by hydrogenating these resins, and the like.

The softening point of the thickener is preferably 60 to 170 ℃, more preferably 65 to 160 ℃, and further preferably 70 to 150 ℃.

In the present specification, the "softening point" of the thickener means a value measured in accordance with JIS K2531.

The tackifier may be used alone, or two or more different in softening point, structure, and the like may be used in combination.

Among them, in the case of using two or more kinds of tackifiers, it is preferable that the weighted average of the softening points of the plurality of tackifiers falls within the above range.

The content of the tackifier is preferably 0.01 to 65% by mass, more preferably 0.05 to 55% by mass, even more preferably 0.1 to 50% by mass, even more preferably 0.5 to 45% by mass, and even more preferably 1.0 to 40% by mass, based on the total amount (100% by mass) of the active ingredients in the adhesive composition.

(photopolymerization initiator)

In the present embodiment, when the pressure-sensitive adhesive composition contains an energy ray-curable pressure-sensitive adhesive resin as the pressure-sensitive adhesive resin, it is preferable that the pressure-sensitive adhesive composition further contains a photopolymerization initiator.

By containing a photopolymerization initiator, the curing reaction can be sufficiently performed by irradiation with energy rays of relatively low energy.

Examples of the photopolymerization initiator include: 1-hydroxy-cyclohexyl-phenyl-ketone, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzyl phenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, bibenzyl, butanedione, and 8-chloroanthraquinone, and the like.

These photopolymerization initiators may be used alone or in combination of two or more.

The content of the photopolymerization initiator is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 5 parts by mass, and still more preferably 0.05 to 2 parts by mass, based on 100 parts by mass of the energy ray-curable adhesive resin.

(laser absorber)

In the present embodiment, when a laser is used in the adhesive force reducing step of the step (X2), it is preferable that a laser light absorber is contained in the adhesive composition.

Examples of the laser beam absorber include at least one selected from pigments and dyes.

The pigment may be an organic pigment or an inorganic pigment.

Examples of the dye include: basic dyes, acid dyes, disperse dyes, direct dyes, and the like.

Examples of the black pigment include: carbon black, copper oxide, ferroferric oxide, manganese dioxide, aniline black, activated carbon and the like.

Examples of the yellow pigment include: chrome yellow, zinc yellow, cadmium yellow, iron oxide yellow, mineral fast yellow, nickel titanium yellow, narlesh yellow, naphthol yellow S, hansa yellow, benzidine yellow G, benzidine yellow GR, quinoline yellow lake, permanent yellow NCG, lemon yellow lake, and the like.

Examples of orange pigments include: red chrome yellow, molybdate orange, pigment orange GTR, pyrazolone orange, sulfide-resistant orange, indanthrene brilliant orange RK, benzidine orange G, indanthrene brilliant orange GKM, and the like.

Examples of the red pigment include: laterite, cadmium Red, lead Red, mercury sulfide, cadmium, permanent Red 4R, lithol Red, pyrazolone Red, Watching Red (Watching Red), calcium salt, lake Red D, brilliant carmine 6B, eosin lake, rhodamine lake B, alizarin lake, and brilliant carmine 3B, and the like.

Examples of violet pigments include: manganese violet, permanent violet B, methyl violet lake, etc.

Examples of the blue pigment include: prussian blue, cobalt blue, alkali blue lake, victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partial chloride, fast sky blue, and indanthrene blue BC, and the like.

Examples of the green pigment include: chromium Green, chromium oxide, pigment Green B, malachite Green lake, and finally Yellow Green G (Final Yellow Green G), and the like.

Examples of the dye include: nigrosine, methylene blue, rose bengal, quinoline yellow, ultramarine blue, and the like.

The content of the laser absorber is preferably 0.01 to 10 mass%, more preferably 0.05 to 7 mass%, and still more preferably 0.1 to 5 mass% with respect to the total amount of the binder composition.

(additive for adhesive)

The pressure-sensitive adhesive composition as a material for forming the pressure-sensitive adhesive layer (X1) may contain, in addition to the above-mentioned additives, an additive for a pressure-sensitive adhesive used in a conventional pressure-sensitive adhesive.

Examples of such additives for adhesives include: antioxidants, softeners (plasticizers), rust inhibitors, retarders, reaction accelerators (catalysts), ultraviolet absorbers, and the like.

These additives for adhesives may be used alone or in combination of two or more.

When these additives for adhesives are contained, the content of each additive for adhesives is preferably 0.0001 to 20 parts by mass, more preferably 0.001 to 10 parts by mass, per 100 parts by mass of the adhesive resin.

< adhesive layer (X2) >

When the pressure-sensitive adhesive sheet (X) is a double-sided pressure-sensitive adhesive sheet, the pressure-sensitive adhesive layer (X2) of the double-sided pressure-sensitive adhesive sheet may contain a pressure-sensitive adhesive resin, and may contain an adhesive additive such as a crosslinking agent, a tackifier, a polymerizable compound, or a polymerization initiator, as necessary.

The composition and form of the pressure-sensitive adhesive layer (X2) are preferably the same as those of the pressure-sensitive adhesive layer (X1). The compositions of the pressure-sensitive adhesive layer (X1) and the pressure-sensitive adhesive layer (X2) may be the same or different. The pressure-sensitive adhesive layer (X1) and the pressure-sensitive adhesive layer (X2) may be in the same form or in different forms.

The thicknesses of the pressure-sensitive adhesive layer (X1) and the pressure-sensitive adhesive layer (X2) are not particularly limited, but are preferably about 1 to 50 μm, more preferably 2 to 30 μm.

The thicknesses of the adhesive layer (X1) and the adhesive layer (X2) may be the same or different.

< Release Material >

The pressure-sensitive adhesive sheet (X) may further comprise a release agent on the pressure-sensitive adhesive surface of either or both of the pressure-sensitive adhesive layer (X1) of the pressure-sensitive adhesive sheet (X) and the pressure-sensitive adhesive layer (X2) optionally included in the pressure-sensitive adhesive sheet (X).

As the release material, a release sheet subjected to a double-sided release treatment, a release sheet subjected to a single-sided release treatment, or the like can be used, and examples thereof include a material obtained by applying a release agent to a release material substrate.

Examples of the base material for release material include: high quality paper, cellophane, kraft paper and the like; plastic films such as polyester resin films such as polyethylene terephthalate resins, polybutylene terephthalate resins, and polyethylene naphthalate resins, and olefin resin films such as polypropylene resins and polyethylene resins; and so on.

Examples of the release agent include: rubber elastomers such as silicone resins, olefin resins, isoprene resins, and butadiene resins, long-chain alkyl resins, alkyd resins, and fluorine resins.

The thickness of the release agent is not particularly limited, but is preferably 10 to 200. mu.m, more preferably 25 to 170. mu.m, and still more preferably 35 to 80 μm.

< method for producing pressure-sensitive adhesive sheet (X) >

The method for producing the pressure-sensitive adhesive sheet (X) is not particularly limited, and can be produced by a known method. For example, the pressure-sensitive adhesive layer (X1) can be formed on the substrate (Y) by adding an organic solvent to a raw material composition containing the above components (hereinafter also referred to as "pressure-sensitive adhesive layer-forming composition") to prepare a solution of the raw material composition, applying the solution to the substrate (Y) by a known application method to form a coating film, and then drying the coating film.

Alternatively, the pressure-sensitive adhesive sheet (X) having a laminate structure of release material/pressure-sensitive adhesive layer (X1)/substrate (Y) may be produced by applying the solution to the release material by a known application method to form a coating film, drying the coating film to form pressure-sensitive adhesive layer (X1) on the release material, and then bonding substrate (Y) to pressure-sensitive adhesive layer (X1).

Examples of the organic solvent used include: toluene, ethyl acetate, methyl ethyl ketone, and the like.

When the organic solvent is blended, the solid content concentration of the solution of the pressure-sensitive adhesive layer-forming composition is preferably 10 to 80% by mass, more preferably 25 to 70% by mass, and still more preferably 45 to 65% by mass.

Examples of the coating method include: spin coating, spray coating, wire bar coating, blade coating, roll blade coating, die coating, gravure coating, and the like.

[ film Forming for protective film ]

The protective film forming film is not particularly limited, and preferably contains a polymer component (B) and a curable component (C), and may further contain a colorant (D), a coupling agent (E), an inorganic filler (F), and a general-purpose additive (G).

The following describes the components (B) to (G) contained in the protective film forming film.

< Polymer component (B) >

The "polymer component" is a compound having a weight average molecular weight (Mw) of 2 ten thousand or more and at least one kind of repeating unit. By incorporating the polymerizable component (B) into the protective film forming film, flexibility and film formability can be mainly imparted to the protective film forming film, and the sheet property retention can be improved.

The weight average molecular weight (Mw) of the polymer component (B) is preferably 2 to 300 ten thousand, more preferably 5 to 200 ten thousand, and further preferably 10 to 150 ten thousand.

The content of the polymer component (B) is preferably 5 to 50 mass%, more preferably 8 to 40 mass%, further preferably 10 to 30 mass%, and further preferably 12 to 25 mass% with respect to the total amount (100 mass%) of the protective film forming film.

The polymer component (B) is preferably an acrylic polymer (B1), and a non-acrylic polymer (B2) other than the acrylic polymer (B1), such as a polyester, phenoxy resin, polycarbonate, polyether, polyurethane, polysiloxane, or rubber polymer, may be used.

These polymer components may be used alone or in combination of two or more.

(acrylic Polymer (B1))

From the viewpoint of imparting flexibility and film-forming properties to the protective film-forming film, the weight average molecular weight (Mw) of the acrylic polymer (B1) is preferably from 2 to 300 million, more preferably from 10 to 150 million, even more preferably from 15 to 120 million, and even more preferably from 25 to 100 million.

The glass transition temperature (Tg) of the acrylic polymer (B1) is preferably-60 to 50 ℃, more preferably-50 to 40 ℃, even more preferably-40 to 30 ℃, and even more preferably-35 to 20 ℃ from the viewpoints of adhesion of a protective film formed of a protective film to an adherend and improvement of reliability of a chip with the protective film.

The acrylic polymer (B1) is a polymer containing an alkyl (meth) acrylate as a main component, and specifically, an acrylic polymer containing a structural unit (B1) derived from an alkyl (meth) acrylate having an alkyl group with 1 to 18 carbon atoms is preferable, and an acrylic copolymer containing a structural unit (B2) derived from a functional group-containing monomer together with a structural unit (B1) is more preferable.

The component (B1) may be used alone or in combination of two or more.

When the component (B1) is a copolymer, the form of the copolymer may be any of a block copolymer, a random copolymer, an alternating copolymer, and a graft copolymer.

(structural unit (b1))

The alkyl group of the alkyl (meth) acrylate constituting the structural unit (b1) preferably has 1 to 18 carbon atoms, more preferably 1 to 12 carbon atoms, and still more preferably 1 to 8 carbon atoms, from the viewpoint of imparting flexibility and film-forming properties to the protective film-forming film.

Examples of the alkyl (meth) acrylate include: methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, n-octyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, and the like.

These alkyl (meth) acrylates may be used singly or in combination of two or more.

Among these alkyl (meth) acrylates, alkyl (meth) acrylates having an alkyl group having 4 or more carbon atoms are preferable, alkyl (meth) acrylates having an alkyl group having 4 to 6 carbon atoms are more preferable, and butyl (meth) acrylate is even more preferable.

The content ratio of the structural unit derived from an alkyl (meth) acrylate having an alkyl group with 4 or more carbon atoms relative to the total structural units (100% by mass) of the acrylic polymer (B1) is preferably 1 to 70% by mass, more preferably 5 to 65% by mass, and still more preferably 10 to 60% by mass.

In addition, from the viewpoint of improving the reliability of the chip with the protective film, the alkyl (meth) acrylate having an alkyl group with 1 to 3 carbon atoms is preferable, and the methyl (meth) acrylate is more preferable.

From the above viewpoint, the content ratio of the structural unit derived from an alkyl (meth) acrylate having an alkyl group with 1 to 3 carbon atoms relative to the total structural units (100 mass%) of the acrylic polymer (B1) is preferably 1 to 60 mass%, more preferably 3 to 50 mass%, and still more preferably 5 to 40 mass%.

The content ratio of the structural unit (B1) is preferably 50% by mass or more, more preferably 50 to 99% by mass, even more preferably 55 to 90% by mass, and even more preferably 60 to 80% by mass, based on the total structural units (100% by mass) of the acrylic polymer (B1).

(structural unit (b2))

Examples of the functional group-containing monomer constituting the structural unit (b2) include: hydroxyl group-containing monomers, carboxyl group-containing monomers, epoxy group-containing monomers, amino group-containing monomers, cyano group-containing monomers, ketone group-containing monomers, monomers having a nitrogen atom-containing ring, alkoxysilyl group-containing monomers, and the like.

These functional group-containing monomers may be used alone or in combination of two or more.

Among these functional group-containing monomers, hydroxyl group-containing monomers are preferred.

Examples of the hydroxyl group-containing monomer include those exemplified in the description of the hydroxyl group-containing monomer of the pressure-sensitive adhesive layer (X1), and 2-hydroxyethyl (meth) acrylate is preferred.

As the carboxyl group-containing monomer, those exemplified as the carboxyl group-containing monomer in the adhesive layer (X1) can be cited.

By using the carboxyl group-containing monomer, a carboxyl group can be introduced into the acrylic polymer (B1), and when the protective film forming film contains an energy ray-curable component as the curable component (C), the compatibility of the component (C) with the component (B) is improved.

When an epoxy thermosetting component is used as the curable component (C) described later, the carboxyl group is preferably reacted with an epoxy group in the epoxy thermosetting component, and therefore the content of the structural unit derived from the carboxyl group-containing monomer is preferably small.

When the epoxy thermosetting component is used as the curable component (C), the content of the structural unit derived from the carboxyl group-containing monomer is preferably 0 to 10% by mass, more preferably 0 to 5% by mass, even more preferably 0 to 2% by mass, and even more preferably 0% by mass, based on the total structural units (100% by mass) of the acrylic polymer (a 1).

Examples of the epoxy group-containing monomer include epoxy group-containing (meth) acrylates and non-acrylic epoxy group-containing monomers.

Examples of the epoxy group-containing (meth) acrylate include: glycidyl (meth) acrylate, β -methylglycidyl (meth) acrylate, (3, 4-epoxycyclohexyl) methyl (meth) acrylate, 3-epoxycyclo-2-hydroxypropyl (meth) acrylate, and the like.

Further, examples of the non-acrylic epoxy group-containing monomer include: glycidyl crotonate, allyl glycidyl ether, and the like.

Of these, epoxy group-containing (meth) acrylates are preferable, and glycidyl (meth) acrylate is more preferable.

From the viewpoint of facilitating further improvement in the sublimability of the protective film, the content ratio of the structural unit derived from the epoxy group-containing monomer to the entire structural unit (100 mass%) of the acrylic polymer (B1) is preferably 1 to 30 mass%, more preferably 5 to 27 mass%, and still more preferably 10 to 24 mass%.

The content of the structural unit (B2) is preferably 1 to 50 mass%, more preferably 5 to 45 mass%, even more preferably 10 to 40 mass%, and even more preferably 20 to 40 mass% with respect to the total structural units (100 mass%) of the acrylic polymer (B1).

(structural units derived from other monomers)

The acrylic polymer (B1) may have a structural unit derived from another monomer than the above-mentioned structural units (B1) and (B2) within the range not to impair the effects of the present invention.

Examples of the other monomers include: vinyl acetate, styrene, ethylene, alpha-olefins, and the like.

(non-acrylic resin (B2))

The protective film-forming film may contain a non-acrylic resin (B2) as a resin component other than the acrylic polymer (B1) as required.

Examples of the non-acrylic resin (B2) include: polyesters, phenoxy resins, polycarbonates, polyethers, polyurethanes, polysiloxanes, rubber-based polymers, and the like.

These resins may be used alone or in combination of two or more.

The weight average molecular weight of the non-acrylic resin (B2) is preferably 2 ten thousand or more, more preferably 2 to 10 ten thousand, and further preferably 2 to 8 ten thousand.

The non-acrylic resin (B2) may be used alone, but when the pressure-sensitive adhesive sheet is laminated with a protective film-forming film by using it in combination with the acrylic polymer (B1), interlayer peeling can be easily performed, and generation of voids and the like can be suppressed.

When the non-acrylic resin (B2) is used in combination with the acrylic polymer (B1), the mass ratio [ (B2)/(B1) ] of the non-acrylic resin (B2) to the acrylic polymer (B1) is preferably 1/99 to 60/40, and more preferably 1/99 to 30/70, from the above viewpoint.

When the structural unit constituting the acrylic polymer (B1) contains a structural unit derived from an epoxy group-containing monomer, the acrylic polymer (B1) and the epoxy group-containing phenoxy resin have thermosetting properties, but they are not the curable component (C) and are considered to be included in the concept of the polymer component (B).

< curable component (C) >

The curable component (C) functions to cure the protective film-forming film to form a hard protective film, and is a compound having a weight average molecular weight of less than 2 ten thousand.

The curable component (C) is preferably a thermosetting component (C1) and/or an energy ray curable component (C2), and from the viewpoint of sufficiently advancing the curing reaction and reducing the cost, it is more preferably at least a thermosetting component (C1).

The thermosetting component (C1) preferably contains at least a compound having a functional group which reacts by heating.

The energy ray-curable component (C2) contains a compound (C21) having a functional group that reacts upon irradiation with an energy ray, and undergoes polymerization curing upon irradiation with an energy ray such as ultraviolet light or an electron beam.

The functional groups of these curable components react with each other to form a three-dimensional network structure, thereby achieving curing.

The weight average molecular weight (Mw) of the curable component (C) is preferably less than 20,000, more preferably 10,000 or less, and even more preferably 100 to 10,000, from the viewpoints of suppressing the viscosity of the composition for forming a protective film forming film, improving the workability, and the like by using it in combination with the component (B).

(thermosetting component (C1))

As the thermosetting component (C1), an epoxy thermosetting component is preferable.

The epoxy thermosetting component is preferably used in combination with a compound having an epoxy group (C11) and a thermosetting agent (C12).

Examples of the compound (C11) having an epoxy group (hereinafter, also referred to as "epoxy compound (C11)") include: polyfunctional epoxy resins, bisphenol a diglycidyl ethers and hydrogenated products thereof, o-cresol novolac epoxy resins, dicyclopentadiene epoxy resins, biphenyl epoxy resins, bisphenol a epoxy resins, bisphenol F epoxy resins, phenylene skeleton epoxy resins, and the like, and epoxy compounds having 2 or more functions in the molecule.

These epoxy compounds (C11) may be used alone or in combination of two or more.

The content of the epoxy compound (C11) is preferably 1 to 500 parts by mass, more preferably 3 to 300 parts by mass, still more preferably 10 to 150 parts by mass, and still more preferably 20 to 120 parts by mass, based on 100 parts by mass of the component (B).

(Heat-curing agent (C12))

The heat-curing agent (C12) functions as a curing agent for the epoxy compound (C11).

The heat-curing agent is preferably a compound having 2 or more functional groups capable of reacting with an epoxy group in 1 molecule.

Examples of the functional group include a phenolic hydroxyl group, an alcoholic hydroxyl group, an amino group, a carboxyl group, and an acid anhydride group (acid anhydride structure). Among these functional groups, a phenolic hydroxyl group, an amino group, or an acid anhydride group is preferable, a phenolic hydroxyl group or an amino group is more preferable, and an amino group is further preferable.

Examples of the phenolic thermosetting agent having a phenolic hydroxyl group include: polyfunctional phenol resins, biphenols, novolak-type phenol resins, dicyclopentadiene-type phenol resins, XYLOK-type phenol resins, aralkyl-type phenol resins, and the like.

Examples of the amine-based heat-curing agent having an amino group include Dicyandiamide (DICY).

These heat-curing agents (C12) may be used alone or in combination of two or more.

The content of the thermosetting agent (C12) is preferably 0.1 to 500 parts by mass, more preferably 1 to 200 parts by mass, based on 100 parts by mass of the epoxy compound (C11).

(curing Accelerator (C13))

In order to adjust the speed of thermal curing of the protective film-forming film, a curing accelerator (C13) may also be used. The curing accelerator (C13) is preferably used in combination with the epoxy compound (C11) as the thermosetting component (C1).

Examples of the curing accelerator (C13) 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; tetraphenylboron salts such as tetraphenylphosphonium tetraphenylborate and triphenylphosphine tetraphenylborate.

These curing accelerators (C13) may be used alone or in combination of two or more.

From the viewpoint of improving the adhesiveness of the protective film formed of the protective film-forming film and the viewpoint of improving the reliability of the chip with the protective film, the content of the curing accelerator (C13) is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 6 parts by mass, and still more preferably 0.3 to 4 parts by mass, relative to 100 parts by mass of the total amount of the epoxy compound (C11) and the thermosetting agent (C12).

(energy ray-curable component (C2))

As the energy ray-curable component (C2), a compound (C21) having a functional group which reacts by irradiation with an energy ray may be used alone, but it is preferable to use the compound (C21) in combination with a photopolymerization initiator (C22).

(Compound (C21) having functional group that reacts when irradiated with energy ray)

Examples of the compound (C21) having a functional group that reacts upon irradiation with an energy ray (hereinafter, also referred to as "energy ray-reactive compound (C21)") include: trimethylolpropane triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, 1, 4-butanediol diacrylate, 1, 6-hexanediol diacrylate, oligoester acrylates, urethane acrylate oligomers, epoxy acrylates, polyether acrylates, itaconic acid oligomers, and the like.

These energy ray-reactive compounds (C21) may be used alone or in combination of two or more.

The weight average molecular weight (Mw) of the energy ray-reactive compound (C21) is preferably 100 to 30,000, more preferably 300 to 10,000.

The content of the energy ray-reactive compound (C21) is preferably 1 to 1,500 parts by mass, more preferably 3 to 1,200 parts by mass, based on 100 parts by mass of the component (B).

(photopolymerization initiator (C22))

By using the energy ray-reactive compound (C21) in combination with the photopolymerization initiator (C22), the polymerization curing time can be shortened, and the curing of the protective film-forming film can be performed even with a small amount of light irradiation.

Examples of the photopolymerization initiator (C22) include those described above.

The content of the photopolymerization initiator (C22) is preferably 0.1 to 10 parts by mass, more preferably 1 to 5 parts by mass, per 100 parts by mass of the energy ray-reactive compound (C21), from the viewpoint of sufficiently advancing the curing reaction and suppressing the generation of residues.

The content of the component (C) is preferably 5 to 50 mass%, more preferably 8 to 40 mass%, further preferably 10 to 30 mass%, and further preferably 12 to 25 mass% with respect to the total amount (100 mass%) of the protective film forming film.

The content of the component (C) means: the total content of the thermosetting component (C1) containing the epoxy compound (C11), the thermosetting agent (C12), and the curing accelerator (C13), and the energy ray-curable component (C2) containing the energy ray-reactive compound (C21) and the photopolymerization initiator (C22).

< colorant (D) >

The protective film-forming film may also further contain a colorant (D).

When the protective film forming film contains the colorant (D), the adhesive layer (X1) is sublimated and the protective film is also sublimated to generate gas when the adhesive layer (X1) is irradiated with laser light, so that the adhesion between the semiconductor chip with the protective film to be peeled and the adhesive layer (X1) can be more effectively reduced.

But it is not necessary that the laser light reach the protective film. By preventing the laser light from reaching the protective film, the semiconductor chip with the protective film can be selectively peeled without causing laser traces in the protective film of the semiconductor chip with the protective film that needs to be peeled.

As the colorant (D), the same ones as those exemplified as the laser light absorber can be cited.

The colorant (D) may be used alone or in combination of two or more.

The content of the colorant (D) is preferably 0.1 to 30% by mass, more preferably 0.5 to 25% by mass, even more preferably 1.0 to 15% by mass, and even more preferably 1.2 to 5% by mass, based on the total amount (100% by mass) of the protective film-forming film.

< coupling agent (E) >

The protective film forming film preferably further contains a coupling agent (E).

By including the coupling agent (E), the polymer component in the protective film-forming film can be bonded to the surface of the semiconductor chip or the surface of the filler as the adherend, whereby the adhesiveness and the cohesive property can be improved. In addition, the water resistance can also be improved without impairing the heat resistance of the protective film formed of the protective film forming film.

The coupling agent (E) is preferably a compound that reacts with the functional groups of the components (B) and (C), and more preferably a silane coupling agent.

Examples of the silane coupling agent include: gamma-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropylmethyldiethoxysilane, beta- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, gamma- (methacryloxypropyl) trimethoxysilane, gamma-aminopropyltrimethoxysilane, N-6- (aminoethyl) -gamma-aminopropylmethyldiethoxysilane, N-phenyl-gamma-aminopropyltrimethoxysilane, gamma-ureidopropyltriethoxysilane, gamma-mercaptopropyltrimethoxysilane, gamma-mercaptopropylmethyldimethoxysilane, bis (3-triethoxysilylpropyl) tetrasulfide, beta-3, 4-epoxycyclohexyl) ethyltrimethoxysilane, gamma-glycidoxypropyl-trimethoxysilane, gamma-aminopropyltriethoxysilane, gamma-mercaptopropyltrimethoxysilane, gamma-mercaptopropylmethyldimethoxysilane, gamma-glycidoxypropyl-trimethoxysilane, gamma-glycidoxypropyl-vinyltrimethoxysilane, beta-glycidoxy-beta-3-glycidoxypropyl-ethyltrimethoxysilane, gamma-glycidoxypropyl-trimethoxysilane, gamma-vinyltrimethoxysilane, gamma-glycidoxypropyl-trimethoxysilane, gamma-vinyltrimethoxysilane, gamma-glycidoxypropyl-vinyltrimethoxysilane, gamma-vinyltrimethoxysilane, or-vinylsulfide, or a-derivative, or a derivative of a-derivative of a compound, or a derivative of a compound or a compound of a type, or a compound of a type, or a compound of a type, or a compound of a type, or a compound of a type, or a compound of a type, or a compound of, Methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, imidazolesilane and the like.

These coupling agents (E) may be used alone or in combination of two or more.

As the coupling agent (E), an oligomer type coupling agent is preferable.

The molecular weight of the coupling agent (E) including the oligomer type coupling agent is preferably 100 to 15,000, more preferably 150 to 10,000, more preferably 200 to 5,000, further preferably 250 to 3,000, and further preferably 350 to 2,000.

The content of the coupling agent (E) is preferably 0.01 to 10 mass%, more preferably 0.05 to 7 mass%, even more preferably 0.10 to 4 mass%, and even more preferably 0.15 to 2 mass% with respect to the total amount (100 mass%) of the protective film forming film.

< inorganic Filler (F) >

The protective film forming film preferably further contains an inorganic filler (F).

By including the inorganic filler (F), the thermal expansion coefficient of the protective film after curing of the protective film forming film can be adjusted to an appropriate range, and the reliability of the semiconductor device can be improved by optimizing the thermal expansion coefficient of the protective film after curing with respect to the semiconductor chip. In addition, the moisture absorption rate of the cured protective film can be reduced.

Examples of the inorganic filler (F) include: powders of silica, alumina, talc, calcium carbonate, titanium oxide, iron oxide, silicon carbide, boron nitride and the like, and beads, single crystal fibers, glass fibers and the like obtained by spheroidizing them

These inorganic fillers (F) may be used alone or in combination of two or more.

Of these, silica or alumina is preferable.

The average particle diameter of the inorganic filler (F) is preferably 0.3 to 50 μm, more preferably 0.5 to 30 μm, and still more preferably 0.7 to 10 μm, from the viewpoint of increasing the gloss value of a protective film formed from a protective film-forming film.

In the present invention, the average particle diameter of the inorganic filler (F) is a value measured by using a laser diffraction scattering particle size distribution measuring apparatus.

The content of the inorganic filler (F) is preferably 25 to 80 mass%, more preferably 30 to 70 mass%, even more preferably 40 to 65 mass%, and even more preferably 45 to 60 mass% with respect to the total amount (100 mass%) of the protective film forming film.

< general additive (G) >

In addition to the above, various additives may be added to the protective film-forming film as needed.

Examples of the various additives include: crosslinking agent, leveling agent, plasticizer, antistatic agent, antioxidant, ion trapping agent, getter, chain transfer agent and the like.

< method for producing protective film-forming film >

The method for producing the protective film-forming film is not particularly limited, and can be produced by a known method. For example, the protective film can be produced by adding an organic solvent to a raw material composition containing the above-mentioned components (hereinafter, also referred to as "protective film forming composition") to prepare a solution of the protective film forming composition, applying the solution to the above-mentioned release sheet by a known coating method to form a coating film, and then drying the coating film to form a protective film forming film on the release sheet.

The solid content concentration of the solution of the protective film forming composition when the organic solvent is blended is preferably 10 to 80 mass%, more preferably 20 to 70 mass%, and still more preferably 30 to 65 mass%.

The protective film-forming film may be a single layer or a multilayer structure of two or more kinds.

The thickness of the protective film-forming film is not particularly limited, but is preferably 3 to 300 μm, more preferably 5 to 250 μm, and further preferably 7 to 200 μm, and when the protective film-forming film has a multilayer structure, the total thickness (the total thickness of the layers) is also preferably within this range.

< method for producing protective film-Forming laminate >

The method for producing the protective film-forming laminate having a laminate structure of the protective film-forming film and the adhesive sheet (X) is not particularly limited, and the laminate can be produced by a known method.

First, as described in the method for manufacturing the protective film forming film, the protective film forming film is formed on the release sheet. Next, by laminating the pressure-sensitive adhesive layer (X1) of the pressure-sensitive adhesive sheet (X) to the protective film forming film formed on the release sheet, a protective film forming laminate having a laminate structure of release sheet/protective film forming film/pressure-sensitive adhesive layer (X1) can be produced.

[ desired method for picking up adherend ]

The method of picking up the adherend whose adhesive strength with the adhesive layer (X1) has been reduced by the step (S2) is not particularly limited, and examples thereof include: a method of pushing up the adhesive sheet (X) from the lower side to the upper side through a needle or the like and picking up the adhesive sheet by a vacuum collet or the like.

Here, in the manufacturing method according to one embodiment of the present invention, it is preferable that the adherend whose adhesion to the pressure-sensitive adhesive layer (X1) has been reduced by the step (S2) is picked up by the following method.

That is, it is preferable to perform the following step (SP1) before the step (S2) or after the step (S2), and perform the following step (SP2) after the step (SP1) and after the step (S2).

Step (SP 1): laminating the plurality of adherends to the adhesive layer (Z1) of the transfer sheet (Z) having the adhesive layer (Z1) with the adhesive layer (X1) and the transfer sheet (Z) interposed therebetween by using a surface of the plurality of adherends opposite to the adherend surface of the adhesive layer (X1) as a laminating surface;

In the following description, this method is also referred to as a "transfer method".

In the step (SP1), as shown in fig. 8, the plurality of adherends 1 (including a part of the adherend 1a that needs to be peeled) are bonded to the adhesive layer (Z1) of the transfer sheet (Z) having the adhesive layer (Z1) with the bonding surface being the surface opposite to the bonding surface of the adhesive layer (X1), and the adhesive layer (X1) and the transfer sheet (Z) are laminated with the plurality of adherends 1 interposed therebetween.

< transfer sheet (Z) >

The transfer sheet (Z) has a laminated structure of a base material (Y') and an adhesive layer (Z1).

The substrate (Y') may be the same as that listed as the substrate (Y) of the adhesive sheet (X), and may have the same thickness as that of the substrate (Y).

The same adhesive layer (Z1) as that listed for the adhesive layer (X1) of the adhesive sheet (X) may be used.

The step (SP1) may be performed before the step (S2) or after the step (S2). At any time, the adhesive force reducing step in the step (S2) is not affected.

Further, the step (S2) is performed to separate the transfer sheet (Z) from the pressure-sensitive adhesive sheet (X) as shown in fig. 8 in a state where the adhesive strength of a part of the adherend 1a to the pressure-sensitive adhesive layer (X1) is reduced. Thus, only a part of the adherend 1a can be peeled off from the adhesive sheet (X), and a part of the adherend 1a can be transferred to the transfer sheet (Z).

Here, the transfer method is not limited to the above method. For example, the step (S2) may be performed to adsorb and transfer a part of the adherend 1a to the porous stage by disposing the porous stage so as to be in contact with the surface of the plurality of adherends 1 opposite to the bonding surface of the adhesive layer (X1) in a state where the adhesion force with respect to the adhesive layer (X1) of the part of the adherend 1a is reduced. The suction by the porous table may be selectively performed only on a part of the adherend 1a whose adhesive force has been reduced, or may be performed on the entire surface of the adhesive layer (X1). When the entire surface of the pressure-sensitive adhesive layer (X1) is adsorbed by the porous stage, the pressure-sensitive adhesive layer (X1) adsorbed by the porous stage is separated from the porous stage, whereby only a part of the adherend 1a having a reduced adhesive strength is adsorbed and transferred to the porous stage. The average pore diameter of the porous stage used in this case is preferably 60 μm or less, more preferably 55 μm or less, from the viewpoint of transferring by adsorbing only a part of the adherend 1a, which has been reduced in adhesion to the pressure-sensitive adhesive layer (X1), by sucking the entire surface with a weak force. The porosity is preferably 30% to 60%, more preferably 45% to 60%.

For example, the step (S2) may be performed to grasp and transfer the part of the adherend 1a to the electrostatic chuck by disposing the electrostatic chuck in contact with the surface of the plurality of semiconductor chips 11 with the protective film opposite to the protective film side in a state where the adhesive strength of the part of the adherend 1a to the adhesive layer (X1) is reduced. The electrostatic chuck may selectively hold only a part of the adherend 1a whose adhesive force has been reduced, or may hold the entire surface of the adhesive layer (X1). When the entire surface of the adhesive layer (X1) is gripped by the electrostatic chuck, the adhesive layer (X1) gripped by the electrostatic chuck is separated from the electrostatic chuck, whereby only a part of the adherend 1a whose adhesive strength has been reduced is gripped and transferred to the electrostatic chuck. In this case, from the viewpoint of holding the entire surface with a weak force and transferring only a part of the adherend 1a, which has a reduced adhesion force to the adhesive layer (X1), by holding it with a transfer, an adhesive sheet in which a base material and an adhesive layer are laminated may be attached to an electrostatic chuck as a cushion material to weaken the holding force.

[ method for producing semiconductor chip with protective film ]

A method for manufacturing a semiconductor chip according to an embodiment of the present invention includes the steps of: the peeling method of the present invention or the peeling method of one embodiment of the present invention including steps (S1) and (S2) is performed with the semiconductor chip or the semiconductor chip with the protective film as an adherend.

In particular, the method for manufacturing a semiconductor chip with a protective film according to the present invention is preferable because the step of the peeling method according to one embodiment of the present invention, which includes the steps (S1-1) to (S1-2) in order of the step (S1) performed with the semiconductor chip with a protective film as an adherend, can efficiently manufacture the semiconductor chip with a protective film from the semiconductor wafer with a protective film.

Further, the method is preferable because the method for manufacturing a semiconductor wafer with a protective film, which comprises the steps (S1-1) to (S1-2) in this order and the step (S1) of using the semiconductor chip with a protective film as an adherend, can efficiently manufacture the semiconductor chip with a protective film from the semiconductor wafer.

[ method for manufacturing semiconductor device ]

In this specification, the term "semiconductor device" refers to all devices that can function by utilizing semiconductor characteristics and that can be used for processors, memories, sensors, and the like.

A method for manufacturing a semiconductor device according to an embodiment of the present invention includes the steps of: the peeling method of the present invention or the peeling method of one embodiment of the present invention including steps (S1) and (S2) is performed with the semiconductor chip or the semiconductor chip with the protective film as an adherend. Therefore, only a part of the plurality of semiconductor chips or the semiconductor chip with the protective film can be supplied to the processing step of the semiconductor device. Specifically, only a part of the plurality of semiconductor chips or the semiconductor chip with the protective film can be subjected to the step of assembling the semiconductor device. For example, only a good semiconductor chip or a semiconductor chip with a protective film can be selectively subjected to a step of assembling the semiconductor device, and the like, and thus the yield of the semiconductor device can be improved.

Examples

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples.

10 semiconductor chips with protective films (chip size: 1 mm. times.1 mm, chip thickness: 200 μm, protective film thickness: 25 μm) were arranged in series at a chip interval of 30 μm on the adhesive layer (X1) of the adhesive sheet (X), and the adhesive sheet (X) to which a plurality of semiconductor chips with protective films were bonded was prepared by bonding with the protective film side as the bonding surface.

The pressure-sensitive adhesive sheet (X) has a structure in which a pressure-sensitive adhesive layer (X1) is laminated on a substrate (Y). Details of the substrate (Y) and the adhesive layer (X1) are as follows. A

Substrate (Y): a polyethylene film having a thickness of 80 μm and an arithmetic average roughness Ra of 0.1 μm opposite to the surface on which the pressure-sensitive adhesive layer (X1) was formed

Adhesive layer (X1): an adhesive layer formed from the following adhesive composition and having a thickness of 10 μm

The adhesive sheet (X) was produced in the following manner.

First, an adhesive composition was prepared. Specifically, an energy ray-curable polymer was obtained by reacting an acrylic copolymer obtained by reacting butyl acrylate/methyl methacrylate/2-hydroxyethyl acrylate (mass ratio) of 80/5/15 with methacryloyloxyethyl isocyanate (MOI) in an amount of 80 mol% based on the 2-hydroxyethyl acrylate. The weight average molecular weight (Mw) of the energy ray-curable polymer was 40 ten thousand. Further, the glass transition temperature (Tg) was-44 ℃.

100 parts by mass of the obtained energy ray-curable polymer, 3 parts by mass of 1-hydroxycyclohexyl phenyl ketone (product name "Irgacure 184" manufactured by BASF Co., Ltd.) as a photopolymerization initiator, 0.49 parts by mass of a toluene diisocyanate-based crosslinking agent (product name "Coronate L" manufactured by Nippon polyurethane industries, Ltd.) as a crosslinking agent, and 1 part by mass of carbon black (product name "M100" manufactured by Mitsubishi chemical corporation) were mixed in a solvent to obtain an adhesive composition.

Next, the adhesive composition is applied to a substrate (Y) and heated to dry, thereby producing an adhesive sheet (X).

The protective film forming film and the curing conditions for forming the protective film of the semiconductor chip with the protective film are as follows.

Protective film formation film: ADWILL LC2850(25)

Curing conditions: 130 ℃ for 2 hours

A semiconductor chip with a protective film (1) in an adhesive sheet (X) in which a plurality of semiconductor chips with protective films are bonded is irradiated with laser light from a substrate (Y) side. The irradiation conditions are as follows.

(conditions of laser irradiation)

Laser irradiation apparatus: CSM3000M, manufactured by EO Technics corporation, Green light solid laser (wavelength: 532nm)

Frequency: 20,000Hz to 25,000Hz

Scanning speed: 100 mm/s

Output power: 0.12W-0.82W

Beam diameter: 35 μm

(results of experiments)

The adhesive sheet (X) to which a plurality of semiconductor chips with protective films are bonded is irradiated with laser light from the base material (Y) side in the vicinity of the bonding surface of the adhesive layer (X1) to the semiconductor chip with protective film in the region where 1 semiconductor chip with protective film is bonded.

As a result, it was confirmed by visual observation from the base material (Y) side that an air pocket was formed at the interface between the 1 semiconductor chip with a protective film and the pressure-sensitive adhesive layer (X1), and it was found that a significant reduction in adhesion to the pressure-sensitive adhesive layer (X1) was achieved only for the 1 semiconductor chip with a protective film. On the other hand, the remaining semiconductor chip with the protective film did not form an air pocket at the interface with the pressure-sensitive adhesive layer (X1), and the adhesive strength with the pressure-sensitive adhesive layer (X1) was not reduced, and the state of being firmly bonded to the pressure-sensitive adhesive layer (X1) was maintained.

In addition, no laser mark was observed in the protective film of the 1 semiconductor chip with a protective film, and deterioration of the protective film due to laser irradiation was also suppressed.

Claims

1. A method for peeling an adherend, comprising the following steps (S1) and (S2),

step (S2): a step of sublimating at least a part of the adhesive layer (X1) in a region where a part of the adherends is bonded, thereby generating gas and reducing the adhesion between the part of adherends and the adhesive layer (X1).

2. The peeling method according to claim 1,

the step (S2) is performed by irradiating the laser beam onto at least a part of the adhesive layer (X1) in the region to which the adherend is partially attached.

3. The peeling method according to claim 1 or 2,

performing the following step (SP1) before the step (S2) or after the step (S2), and performing the following step (SP2) after the following step (SP1) and after the step (S2),

step (SP 1): laminating the adhesive layer (Z1) of a transfer sheet (Z) having an adhesive layer (Z1) to the surface of the plurality of adherends opposite to the surface to be laminated with the adhesive layer (X1), and laminating the adhesive layer (X1) and the transfer sheet (Z) with the plurality of adherends interposed therebetween;

4. The peeling method according to any one of claims 1 to 3,

in the step (S1), a psa sheet (X) having the psa layer (X1) is used.

5. The peeling method according to any one of claims 1 to 4,

the adherend is a semiconductor chip.

6. The peeling method according to any one of claims 1 to 5,

the adherend is a semiconductor chip with a protective film.

7. The peeling method according to claim 5 or 6,

the adhesive sheet (X) is a dicing tape.

8. A method of manufacturing a semiconductor chip, comprising: a process for carrying out the method according to any one of claims 5 to 7.

9. A method of manufacturing a semiconductor device, comprising: a process for carrying out the method according to any one of claims 5 to 7.