Method for peeling semiconductor chips with protective film

Abstract

The present invention relates to: a method for removing a semiconductor chip with a protective film, said method comprising a step (S1) wherein a plurality of semiconductor chips with a protective film are bonded to an adhesive layer (X1), while using the protective film side as a bonding surface, and a step (S2) wherein the protective films of some of the plurality of semiconductor chips with a protective film are at least partially sublimated, thereby producing a gas so as to lower the adhesion between the some semiconductor chips with a protective film and the adhesive layer (X1); a method for producing a semiconductor chip with a protective film, said method comprising a step wherein the above-described method for removing a semiconductor chip with a protective film is carried out; and a method for producing a semiconductor device containing a semiconductor chip with a protective film, said method comprising a step wherein the above-described method for removing a semiconductor chip with a protective film is carried out.

Description

[Technical Field]

[0001] The present invention relates to a method for peeling off a semiconductor chip with a protective film. [Background technology]

[0002] In recent years, semiconductor devices have been manufactured using a mounting method known as the face-down method. In the face-down method, a semiconductor chip having electrodes such as bumps on its circuit surface is used, and the electrodes are bonded to a substrate. As a result, the surface of the semiconductor chip opposite the circuit surface (hereinafter also referred to as the "back surface of the semiconductor chip") may be exposed. This exposed back surface of the semiconductor chip may be protected by a protective film containing an organic material as its main component, and the semiconductor chip may be incorporated into a semiconductor device as a semiconductor chip with a protective film.

[0003] Semiconductor chips with protective films are obtained by dicing a semiconductor wafer with protective films into individual pieces. Generally, dicing of a semiconductor wafer with protective films is performed with the protective film side of the semiconductor wafer with protective films attached to an adhesive layer. Therefore, the semiconductor chips with protective films obtained after dicing are in a state where they are attached to the adhesive layer. When manufacturing a semiconductor device, the semiconductor chips with protective films are peeled off from the adhesive layer and subjected to the next process.

[0004] One known method for peeling a semiconductor chip from a pressure-sensitive adhesive layer is to use a heat-peelable pressure-sensitive adhesive sheet having a substrate on at least one side of which is provided a pressure-sensitive adhesive layer containing thermally expandable microparticles. In this method, when peeling an adherend such as a semiconductor chip from the pressure-sensitive adhesive sheet, the heat-expandable microparticles in the pressure-sensitive adhesive layer are expanded by heating, reducing 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, allowing the adherend to peel from the pressure-sensitive adhesive sheet (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-131507 Summary of the Invention [Problem to be solved by the invention]

[0006] The heat-peelable pressure-sensitive adhesive sheet described in Patent Document 1 is generally used in a manner in which the entire pressure-sensitive adhesive layer is subjected to a heat treatment to reduce the adhesive strength to the adherend over the entire pressure-sensitive adhesive layer, i.e., the adherend is peeled off from the pressure-sensitive adhesive layer all at once.

[0007] However, there are cases where it is desired to selectively peel only a portion of the adherend from the adhesive layer, rather than peeling the entire adherend from the adhesive layer. For example, when the adherend is a semiconductor chip with a protective film, it may be desired to subject only a portion of the semiconductor chips with a protective film attached to the adhesive layer to the next process. In such cases, if the adhesive strength with the semiconductor chips with a protective film is reduced over the entire surface of the adhesive layer, vibrations or the like generated when selectively picking up and moving only the portion of the semiconductor chips with a protective film may cause displacement or peeling from the adhesive layer of the remaining semiconductor chips with a protective film that are not picked up.

[0008] Therefore, the present invention aims to provide a method for peeling off semiconductor chips with protective films, which can selectively reduce the adhesive strength between the adhesive layer and only some of the semiconductor chips with protective films among multiple semiconductor chips with protective films attached to an adhesive layer. [Means for solving the problem]

[0009] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by actively utilizing the protective film provided on the semiconductor chip with the protective film. Specifically, they have found that the above-mentioned problems can be solved by sublimating at least a portion of the protective film of the semiconductor chip with the protective film to be peeled off, generating gas and reducing the adhesive strength with the adhesive layer. After further extensive research, they have completed the present invention.

[0010] That is, the present invention relates to the following [1] to [9]. [1] A method for peeling off a semiconductor chip with a protective film, comprising the following steps (S1) and (S2): Step (S1): A step of attaching a plurality of semiconductor chips with protective films to an adhesive layer (X1) with the protective film side as an attachment surface. Step (S2): A step of sublimating at least a part of the protective film of some of the protective film-equipped semiconductor chips among the plurality of protective film-equipped semiconductor chips to generate gas, thereby reducing the adhesive strength between the some of the protective film-equipped semiconductor chips and the adhesive layer (X1). [2] The peeling method according to the above [1], wherein the step (S1) includes the following steps (S1-1) to (S1-2) in this order: Step (S1-1): A step of adhering a semiconductor wafer with a protective film to an adhesive layer (X1) with the protective film side as an adhesive surface. Step (S1-2): Dicing the semiconductor wafer with the protective film to obtain the plurality of semiconductor chips with the protective film. [3] The peeling method described in [2] above, wherein the semiconductor wafer with a protective film in the step (S1-1) is obtained by adhering a protective film-forming film to a semiconductor wafer and then curing the protective film-forming film. [4] The peeling method according to the above [2], wherein the step (S1-1) is carried out by attaching a semiconductor wafer to the protective film-forming film side of a protective film-forming laminate obtained by laminating a protective film-forming film on the adhesive layer (X1) of an adhesive sheet (X) having the adhesive layer (X1), and then curing the protective film-forming film. [5] The peeling method according to the above [4], wherein the pressure-sensitive adhesive sheet (X) is a dicing tape. [6] The protective film of the semiconductor chip with the protective film is a protective film capable of absorbing laser light, The peeling method according to any one of the above [1] to [5], wherein the step (S2) is carried out by irradiating the laser light onto at least a part of the protective film of the part of the semiconductor chips with the protective film. [7] The peeling method according to any one of [1] to [6] above, wherein the following step (SP1) is carried out before or after the step (S2), and the following step (SP2) is carried out after the step (SP1) and after the step (S2). Step (SP1): A step of attaching the adhesive layer (Z1) of a transfer sheet (Z) having the adhesive layer (Z1) to the surfaces of the plurality of semiconductor chips with protective films opposite to the protective film side as an attachment surface, and laminating the adhesive layer (X1) and the transfer sheet (Z) via the plurality of semiconductor chips with protective films. Step (SP2): A step of separating the transfer sheet (Z) and the adhesive layer (X1), peeling off only the part of the semiconductor chips with protective films from the adhesive layer (X1), and transferring the part of the semiconductor chips with protective films to the transfer sheet (Z). [8] A method for producing a semiconductor chip with a protective film, comprising a step of carrying out the method according to any one of [1] to [7] above. [9] A method for manufacturing a semiconductor device including a semiconductor chip with a protective film, the method comprising carrying out the method according to any one of [1] to [7] above. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a method for peeling off semiconductor chips with protective films, which can selectively reduce the adhesive strength between the adhesive layer and only some of the semiconductor chips with protective films out of multiple semiconductor chips with protective films attached to an adhesive layer. [Brief explanation of the drawings]

[0012] [Figure 1]FIG. 1 is a diagram showing an example of step (S1) of the peeling method of the present invention, where (A) is a top view, and (B-1) and (B-2) are schematic cross-sectional views. [Figure 2] FIG. 2 is a schematic cross-sectional view showing an example of steps (S1-1) and (S1-2) of a peeling method according to one embodiment of the present invention. [Figure 3] FIG. 3 is a schematic cross-sectional view showing an example of step (S2) of the peeling method of the present invention. [Figure 4] 4 is an enlarged schematic cross-sectional view of the area surrounded by the dotted line in FIG. 3, showing the progress of the decrease in adhesive strength. FIG. [Figure 5] FIG. 2 is a schematic cross-sectional view showing an example of steps (SP1) and (SP2) of a peeling method according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] In the present invention, the term "active ingredient" refers to the components contained in the target composition excluding the diluent solvent. The weight average molecular weight (Mw) is a value calculated as a standard polystyrene as measured by gel permeation chromatography (GPC), and specifically, is a value measured based on the method described in the examples. Furthermore, "(meth)acrylic acid" refers to both "acrylic acid" and "methacrylic acid," and the same applies to other similar terms. Furthermore, for preferred numerical ranges (e.g., ranges of content, etc.), the lower and upper limits described in stages can be independently combined. For example, the description "preferably 10 to 90, more preferably 30 to 60" can be combined with the "preferable lower limit (10)" and the "more preferable upper limit (60)" to form "10 to 60."

[0014] [Method for peeling off semiconductor chips with protective film] The method for peeling off a semiconductor chip with a protective film of the present invention includes the following steps (S1) and (S2). Step (S1): A step of attaching a plurality of semiconductor chips with protective films to an adhesive layer (X1) with the protective film side as an attachment surface. Step (S2): A step of sublimating at least a part of the protective film of some of the protective film-equipped semiconductor chips among the plurality of protective film-equipped semiconductor chips to generate gas, thereby reducing the adhesive strength between the some of the protective film-equipped semiconductor chips and the adhesive layer (X1).

[0015] In the following description, the method for peeling off a semiconductor chip with a protective film of the present invention will also be simply referred to as the "peeling method of the present invention." Furthermore, the method for peeling off a semiconductor chip with a protective film according to one embodiment of the present invention will also be simply referred to as "a peeling method according to one embodiment of the present invention." The step (S1) is also referred to as a "preparation step." Furthermore, the step (S2) is also referred to as an "adhesion strength reducing step."

[0016] Step (S1) and step (S2) will be described below.

[0017] [Process (S1): Preparation process] In the step (S1), as shown in FIG. 1, a plurality of semiconductor chips 11 with protective films are attached to an adhesive layer (X1) with the protective films 13 side serving as the attachment surface. The semiconductor chip 11 with a protective film is composed of a semiconductor chip 12 and a protective film 13. The protective film 13 is formed on the surface of the semiconductor chip 12 opposite to the circuit surface 12a, i.e., on 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 μm. The thickness of the protective film 13 is not particularly limited, but is preferably 0.05 μm to 200 μm. The size of the semiconductor chip 12 is not particularly limited, but is usually 5 μm to 15 mm in length and 5 μm to 15 mm in width.

[0018] 1 (B-1), a plurality of semiconductor chips 11 with protective films are attached to the adhesive layer (X1) of an adhesive sheet (X) in which the adhesive layer (X1) is laminated on one side of a substrate (Y), but this is merely one example, and a plurality of semiconductor chips 11 with protective films may be attached to an adhesive layer (X1) that does not have a substrate (Y), as shown in FIG. 1 (B-2). The adhesive layer (X1) that does not have a substrate (Y) is used, for example, by attaching and fixing the surface opposite to the surface to which the plurality of semiconductor chips 11 with protective films are attached to a hard substrate or the like. 1 (B-1)。 For example, the adhesive sheet (X) may have an adhesive layer (X1) on both sides of the base material (Y) (in this case, either one of the adhesive layers (X1) may be the adhesive layer (X2) described later). The adhesive surface of the adhesive layer (X1) may be provided with a release material, and the release material may be peeled off immediately before attaching the plurality of semiconductor chips 11 with protective film to the adhesive layer (X1) to expose the adhesive surface of the adhesive layer (X1).

[0019] <Process (S1-1), Process (S1-2)> Here, in the preparation step for step (S1), it is sufficient to adhere multiple semiconductor chips 11 with protective films to the adhesive layer (X1) as described above, and the procedure for carrying out step (S1) is not limited. However, from the viewpoint of efficiently carrying out the present invention, including the step of singulating the semiconductor wafer with protective films, in one embodiment of the peeling method of the present invention, it is preferable that step (S1) includes the following steps (S1-1) to (S1-2) in this order. Step (S1-1): A step of adhering a semiconductor wafer with a protective film to an adhesive layer (X1) with the protective film side as an adhesive surface. Step (S1-2): Dicing the semiconductor wafer with the protective film to obtain the plurality of semiconductor chips with the protective film.

[0020] (Process (S1-1)) In the step (S1-1), as shown in FIG. 2, the semiconductor wafer 1 with the protective film is attached to the adhesive layer (X1) with the protective film 13 side serving as the attachment surface. In FIG. 2, the semiconductor wafer 1 with a protective film is attached to the adhesive layer (X1) of the adhesive sheet (X), but this is only one example, and the semiconductor wafer 1 with a protective film may also be attached to an adhesive layer (X1) that does not have a substrate (Y). The semiconductor wafer 1 with a protective film 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, that is, on the back surface 2b of the semiconductor wafer 2. Examples of the semiconductor wafer 2 include a silicon wafer, a silicon carbide wafer, a compound semiconductor wafer, a glass wafer, and a sapphire wafer. The back surface of the semiconductor wafer 2 may be appropriately ground to have a thickness of about 3 μm to 500 μm. Furthermore, the shape of the semiconductor wafer 2 is not limited to a circle, but may be an angular shape such as a square or a rectangle. The thickness of the protective film 13 is preferably 0.05 μm to 200 μm.

[0021] (Process (S1-2)) In the step (S1-2), as shown in FIG. 2, the semiconductor wafer 1 with the protective film is diced to obtain a plurality of semiconductor chips 11 with the protective film. The dicing method is not particularly limited, and known methods such as blade dicing, laser dicing, etc. Dicing is performed, for example, by providing cut portions 20 so as to penetrate the semiconductor wafer 2 and the protective film 13. After dicing, an expanding process may be performed to widen the gap between the semiconductor chips 11 with the protective film (the width of the notch 20).

[0022] (Method of manufacturing a semiconductor wafer with a protective film) The method for manufacturing the semiconductor wafer with a protective film used in step (S1-1) is not particularly limited, but from the viewpoint of making the thickness of the protective film uniform and achieving excellent coverage of the back surface of the semiconductor wafer by the protective film, it is preferable that the semiconductor wafer with a protective film is obtained by adhering a protective film-forming film to the semiconductor wafer and then curing the protective film-forming film.

[0023] The protective film-forming film can be cured by either heat curing or curing by irradiation with energy rays, depending on the type of curable component contained in the protective film-forming film. In this specification, the term "energy rays" refers to electromagnetic waves or charged particle beams that have an energy quantum, and examples thereof include ultraviolet rays and electron beams, with ultraviolet rays being preferred. When thermal curing is carried out, the curing temperature is preferably 100° C. to 170° C., and the curing time is preferably 1 hour to 3 hours. The conditions for curing by irradiation with energy rays are determined appropriately depending on the type of energy rays used. For example, when ultraviolet rays are used, the illuminance is preferably 170 mW / cm 2 ~250mW / cm 2 and the light intensity is preferably 600 mJ / cm 2 ~1,000mJ / cm 2 is.

[0024] The timing for hardening the protective film-forming film may be before the semiconductor wafer having the protective film-forming film attached thereto is attached to the adhesive layer (X1), or may be after the semiconductor wafer having the protective film-forming film attached thereto is attached to the adhesive layer (X1). Here, when the protective film-forming film is cured after the semiconductor wafer having the protective film-forming film attached thereto is attached to the pressure-sensitive adhesive layer (X1), it is preferable to attach the protective film-forming film and the pressure-sensitive adhesive layer (X1) together to the back surface 2b of the semiconductor wafer from the viewpoint of simplifying the process. Specifically, it is preferable to use a protective film-forming laminate in which the 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), attach the protective film-forming film side of the protective film-forming laminate to the back surface of the semiconductor wafer, and then cure the protective film-forming film.

[0025] [Process (S2): Adhesive strength reduction process] In step (S2), at least a portion of some of the protective film-equipped semiconductor chips among the plurality of protective film-equipped semiconductor chips is sublimated to generate gas, thereby reducing the adhesive strength between some of the protective film-equipped semiconductor chips and the adhesive layer (X1).

[0026] The inventors came up with the idea of ​​actively utilizing the protective film possessed by the semiconductor chips with protective films to sublimate part of the protective film and generate gas as a method for selectively reducing the adhesive strength of some of the semiconductor chips with protective films among multiple semiconductor chips with protective films with the adhesive layer (X1), and thus completed the present invention.

[0027] The method for sublimating a portion of the protective film to generate gas is not particularly limited, but it is preferable to use a protective film capable of absorbing laser light and irradiate laser light onto at least a portion of the protective film of some of the semiconductor chips with the protective film.

[0028] Fig. 3 shows an embodiment of the step (S2) using laser light. Fig. 4 is an enlarged view of the area enclosed by the dotted line in Fig. 3, and is a diagram schematically showing a state in which the adhesive strength of some of the protective film-equipped semiconductor chips to the pressure-sensitive adhesive layer (X1) is reduced among a plurality of protective film-equipped semiconductor chips. In the step (S2) using laser light, it is preferable to irradiate the protective film of the semiconductor chips with protective film with laser light from the surface of the adhesive layer (X1) opposite to the surface attached to the semiconductor chips with protective film. When using an adhesive sheet (X) with an adhesive layer (X1), it is preferable to irradiate the protective film of some of the semiconductor chips with protective film with laser light L by irradiating laser light L from a laser irradiation device 30 from the substrate (Y) side of the adhesive sheet (X), as shown in Figures 3 and 4. This ablates part of the protective film, generating sublimation gas and reducing the contact area between the protective film and the adhesive layer (X1) around the irradiated area of ​​the laser light L. Then, by expanding the area irradiated with the laser light L onto the protective film, the protective film is ablated over a wider area, generating sublimation gas and further reducing the contact area between the protective film and the adhesive layer (X1). This reduces the adhesive strength between some of the semiconductor chips with protective film 11a and the adhesive layer (X1). Even if the sublimation gas leaks out around some of the semiconductor chips 11a with protective films, the leaked sublimation gas is released from the notches 20. Therefore, it is possible to prevent a decrease in the adhesive strength of the semiconductor chips with protective films that are not desired to be peeled off around some of the semiconductor chips 11a with protective films.

[0029] The laser irradiation device 30 is not particularly limited as long as it is a device that can irradiate laser light that can generate sublimation gas from the protective film, and for example, a laser irradiation device for applying laser marking to the protective film can be used. Examples of such laser irradiation devices include the CSM2000 manufactured by EOTechnics (solid green laser, wavelength: 532 nm), but this device is not necessarily limited to this, and various devices that can emit laser light that can be absorbed by the protective film can be used. The conditions for irradiating the laser beam are not particularly limited as long as the protective film can absorb the laser beam, but from the viewpoint of more efficiently peeling off only some of the semiconductor chips with the protective film, for example, the frequency is preferably 10,000 Hz to 30,000 Hz. The beam diameter of the laser beam is preferably 10 μm to 100 μm, more preferably 20 μm to 40 μm. The output power of the laser beam is preferably 0.1 W to 1.0 W. The scanning speed of the laser beam is preferably 50 to 200 mm / sec.

[0030] Furthermore, the protective film of the semiconductor chip with a protective film to be peeled may be irradiated with laser light only on at least a portion of the surface of the protective film that adheres to the adhesive layer (X1), which may reduce the adhesive strength between the protective film and the adhesive layer (X1). However, from the viewpoint of further reducing the adhesive strength, it is preferable to irradiate at least a certain area of ​​the surface of the protective film that adheres to the adhesive layer (X1). Specifically, the area of ​​the surface of the protective film that adheres to the adhesive layer (X1) that is irradiated with laser light is preferably 50% or more, more preferably 60% or more, even more preferably 70% or more, even more preferably 80% or more, even more preferably 90% or more, and even more preferably 100% (i.e., the entire surface of the protective film) of the entire surface of the protective film that adheres to the adhesive layer (X1). Furthermore, it is preferable to irradiate the protective film with laser light in a distributed manner across multiple regions, rather than irradiating it in a biased manner to a certain region. For example, by irradiating the peripheral and central portions of the protective film with laser light, the contact area between the protective film and the adhesive layer (X1) can be effectively reduced, and therefore the adhesive strength between the protective film and the adhesive layer (X1) can be effectively reduced. As described above, the laser light is preferably irradiated onto the protective film from the surface of the adhesive layer (X1) opposite to the surface attached to the multiple semiconductor chips with protective film, toward the protective film. When an adhesive sheet (X) is used, the laser light is preferably irradiated from the substrate (Y) side toward the protective film. The laser light is preferably adjusted so that it irradiates the adhesive surface of the protective film with the adhesive layer (X1) or its vicinity. Here, "proximity of the adhesive surface of the protective film with the adhesive layer (X1)" means a position within 10 μm of the adhesive surface.

[0031] Next, the configurations of the pressure-sensitive adhesive sheet (X) and the protective film-forming film used in the peeling method of one embodiment of the present invention will be described below.

[0032] [Adhesive Sheet (X)] The pressure-sensitive adhesive sheet (X) has a laminated structure of a substrate (Y) and a pressure-sensitive adhesive layer (X1). The pressure-sensitive adhesive sheet (X) shown in (B-1) of Figure 1 and Figures 2 to 5 is in an embodiment having a pressure-sensitive adhesive layer (X1) on one side of a substrate (Y), but is not limited to this and may be in an embodiment of a double-sided pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer (X2) on the other side of the substrate (Y). In the peeling method according to one aspect of the present invention, the pressure-sensitive adhesive sheet (X) is preferably a dicing tape. Each layer that the pressure-sensitive adhesive sheet (X) may have will be described below.

[0033] <Base material (Y)> The substrate (Y) of the pressure-sensitive adhesive sheet (X) functions as a support for supporting the pressure-sensitive adhesive layer (X1), and is made of, for example, a resin film that is primarily made of a resin-based material and has laser light transparency. Specific examples of resin films include polyethylene films such as low-density polyethylene (LDPE) film, linear low-density polyethylene (LLDPE) film, and high-density polyethylene (HDPE) film, polyolefin films such as polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, ethylene-norbornene copolymer film, and norbornene resin film; ethylene copolymer films such as ethylene-vinyl acetate copolymer film, ethylene-(meth)acrylic acid copolymer film, and ethylene-(meth)acrylic acid ester copolymer film; polyvinyl chloride films such as polyvinyl chloride film and vinyl chloride copolymer film; polyester films such as polyethylene terephthalate film and polybutylene terephthalate film; polyurethane films; polyimide films; polystyrene films; polycarbonate films; fluororesin films, etc. Modified films such as crosslinked films and ionomer films formed by crosslinking the resins forming these films may also be used. The substrate (Y) may be made of one of these resin films alone, or a laminated film made of two or more of them in combination.

[0034] Here, from the viewpoints of versatility, relatively high strength that makes it easy to prevent warping, heat resistance, and improved 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, or a high-density polyethylene (HDPE) film, a polyester film such as a polyethylene terephthalate film or a polybutylene terephthalate film, or a polypropylene film. Specifically, the resin film is preferably a monolayer film having one or more layers selected from the group consisting of a polyethylene film, a polyester film, and a polypropylene film, or a laminate film having two or more layers laminated together. In order to ensure high light transmittance for light of a desired wavelength, it is preferable to increase the smoothness of the first surface of the substrate (Y) (the surface opposite to the surface on which the pressure-sensitive adhesive layer (X1) is formed). Specifically, it is preferable that the arithmetic mean roughness Ra of the first surface of the substrate (Y) is 0.01 μm to 0.8 μm. The arithmetic mean roughness Ra is a value measured in accordance with JIS B 0601:1994.

[0035] The substrate (Y) may contain a colorant, but when laser light is used in the adhesive strength reducing step (S2), the content of the colorant that absorbs the laser light is preferably small from the viewpoint of obtaining a substrate with superior laser light transmittance. Specifically, the content of the colorant that absorbs the laser light is preferably less than 0.1 mass %, more preferably less than 0.01 mass %, even more preferably less than 0.001 mass %, based on the total amount of the substrate (Y), and even more preferably no colorant is contained.

[0036] The thickness of the substrate (Y) is not particularly limited, but is preferably in the range of 20 μm to 450 μm, more preferably 25 μm to 400 μm.

[0037] <Adhesive layer (X1)> The pressure-sensitive adhesive layer (X1) may contain any adhesive resin, and may contain additives for pressure-sensitive adhesives such as a crosslinking agent, a tackifier, a polymerizable compound, and a polymerization initiator, as required. The pressure-sensitive adhesive layer (X1) can be formed from a pressure-sensitive adhesive composition containing a pressure-sensitive adhesive resin. Hereinafter, each component contained in the pressure-sensitive adhesive composition, which is the material for forming the pressure-sensitive adhesive layer (X1), will be described.

[0038] (Adhesive resin) The adhesive resin is preferably a polymer that has adhesiveness by itself and has a mass average molecular weight (Mw) of 10,000 or more. From the viewpoint of improving adhesive strength, the mass average molecular weight (Mw) of the adhesive resin is more preferably from 10,000 to 2,000,000, even more preferably from 20,000 to 1,500,000, and even more preferably from 30,000 to 1,000,000.

[0039] Examples of adhesive resins 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. Furthermore, when these adhesive resins are copolymers having two or more types 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.

[0040] The adhesive resin may be an energy ray curable adhesive resin having a polymerizable functional group introduced into the side chain. Examples of the polymerizable functional group include a (meth)acryloyl group and a vinyl group. The energy rays include ultraviolet rays and electron beams, with ultraviolet rays being preferred.

[0041] The content of the adhesive resin is preferably 30 to 99.99 mass%, more preferably 40 to 99.95 mass%, even more preferably 50 to 99.90 mass%, still more preferably 55 to 99.80 mass%, and even more preferably 60 to 99.50 mass%, relative to the total amount (100 mass%) of the active ingredients of the adhesive composition. In the following description of this specification, "the content of each component relative to the total amount of active ingredients in the pressure-sensitive adhesive composition" is synonymous with "the content of each component in the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition."

[0042] Here, from the viewpoint of exhibiting excellent adhesive strength and suppressing the phenomenon of cutting water penetrating between the adhesive layer (X1) and the protective film during dicing, the adhesive resin preferably contains an acrylic resin. The content of the acrylic resin in the adhesive resin is preferably 30 to 100 mass%, more preferably 50 to 100 mass%, even more preferably 70 to 100 mass%, and still more preferably 85 to 100 mass%, relative to the total amount (100 mass%) of the adhesive resin contained in the adhesive composition.

[0043] (acrylic resin) Examples of acrylic resins that can be used as adhesive resins include polymers containing structural units derived from alkyl (meth)acrylates having a linear or branched alkyl group, and polymers containing structural units derived from (meth)acrylates having a cyclic structure.

[0044] The mass average molecular weight (Mw) of the acrylic resin is preferably 100,000 to 1,500,000, more preferably 200,000 to 1,300,000, even more preferably 350,000 to 1,200,000, and still more preferably 500,000 to 1,100,000.

[0045] 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 (a1')") and a structural unit (a2) derived from a functional group-containing monomer (a2') (hereinafter also referred to as "monomer (a2')").

[0046] The number of carbon atoms in the alkyl group of the monomer (a1') 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 required for an adhesive sheet (dicing tape) and from the viewpoint of suppressing the phenomenon of cutting water penetrating between the adhesive layer (X1) and the protective film during dicing. The alkyl group contained in the monomer (a1') may be a linear alkyl group or a branched alkyl group.

[0047] Examples of the monomer (a1') include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, and stearyl (meth)acrylate. These monomers (a1') may be used alone or in combination of two or more. As the monomer (a1'), butyl (meth)acrylate and 2-ethylhexyl (meth)acrylate are preferred.

[0048] 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 still more preferably 80 to 95.0 mass%, based on all structural units (100 mass%) of the acrylic copolymer (A1).

[0049] Examples of functional groups contained in the monomer (a2') include a hydroxyl group, a carboxyl group, an amino group, and an epoxy group. That is, examples of the monomer (a2') include hydroxyl group-containing monomers, carboxyl group-containing monomers, amino group-containing monomers, and epoxy group-containing monomers. These monomers (a2') may be used alone or in combination of two or more. Among these, hydroxyl group-containing monomers and carboxy group-containing monomers are preferred as the monomer (a2').

[0050] Examples of hydroxyl group-containing monomers 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; and unsaturated alcohols such as vinyl alcohol and allyl alcohol.

[0051] Examples of carboxy group-containing monomers 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 their anhydrides; 2-(acryloyloxy)ethyl succinate; and 2-carboxyethyl (meth)acrylate.

[0052] The content of the structural unit (a2) is preferably 0.1 to 40 mass%, more preferably 0.5 to 35 mass%, even more preferably 1.0 to 30 mass%, and still more preferably 3.0 to 25 mass%, based on all structural units (100 mass%) of the acrylic copolymer (A1).

[0053] The acrylic copolymer (A1) may further include 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 mass%, more preferably 80 to 100 mass%, even more preferably 90 to 100 mass%, and still more preferably 95 to 100 mass%, based on all structural units (100 mass%) of the acrylic copolymer (A1).

[0054] Examples of the monomer (a3') 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, dicyclopentanyl (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, and N-vinylpyrrolidone.

[0055] The acrylic copolymer (A1) may also be an energy ray-curable acrylic copolymer having a polymerizable functional group introduced into the side chain. Examples of the polymerizable functional group include a (meth)acryloyl group and a vinyl group. The energy rays include ultraviolet rays and electron beams, with ultraviolet rays being preferred. The polymerizable functional group can be introduced by reacting an acrylic copolymer having the above-mentioned structural units (a1) and (a2) with a compound having a polymerizable functional group and a substituent capable of bonding to the functional group possessed by the structural unit (a2) of the acrylic copolymer. Examples of the compound include (meth)acryloyloxyethyl isocyanate, (meth)acryloyl isocyanate, and glycidyl (meth)acrylate.

[0056] (Crosslinking agent) The pressure-sensitive adhesive composition preferably further contains a crosslinking agent. The crosslinking agent reacts with a pressure-sensitive adhesive resin having a functional group, such as the above-mentioned acrylic copolymer (A1), and crosslinks the pressure-sensitive adhesive resins together using the functional group as the crosslinking starting point.

[0057] Examples of the crosslinking agent include an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, an aziridine-based crosslinking agent, and a metal chelate-based crosslinking agent. These crosslinking agents may be used alone or in combination of two or more. Among these crosslinking agents, isocyanate-based crosslinking agents are preferred from the viewpoints of increasing cohesive strength and improving adhesive strength, and of easy availability.

[0058] The content of the crosslinking agent is adjusted appropriately depending on the number of functional groups possessed by the adhesive resin, but is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 7 parts by mass, and even more preferably 0.05 to 5 parts by mass per 100 parts by mass of the adhesive resin having functional groups.

[0059] (tackifier) The pressure-sensitive adhesive composition may further contain a tackifier from the viewpoint of further improving adhesive strength. In this specification, the term "tackifier" refers to a component that auxiliary improves the adhesive strength of the above-mentioned adhesive resin, and refers to an oligomer with a mass average molecular weight (Mw) of less than 10,000, and is distinguished from the above-mentioned adhesive resin. The mass average molecular weight (Mw) of the tackifier is preferably from 400 to less than 10,000, more preferably from 500 to 8,000, and even more preferably from 800 to 5,000.

[0060] Examples of tackifiers include rosin resins, terpene resins, styrene resins, C5 petroleum resins obtained by copolymerizing C5 fractions such as pentene, isoprene, piperine, and 1,3-pentadiene produced by thermal decomposition of petroleum naphtha, C9 petroleum resins obtained by copolymerizing C9 fractions such as indene and vinyltoluene produced by thermal decomposition of petroleum naphtha, and hydrogenated resins obtained by hydrogenating these.

[0061] The softening point of the tackifier is preferably 60 to 170°C, more preferably 65 to 160°C, and even more preferably 70 to 150°C. In this specification, the "softening point" of a tackifier means a value measured in accordance with JIS K 2531. The tackifier may be used alone or in combination of two or more types having different softening points, structures, etc. When two or more types of tackifiers are used, it is preferable that the weighted average of the softening points of the tackifiers falls within the above range.

[0062] The content of the tackifier is preferably 0.01 to 65 mass%, more preferably 0.05 to 55 mass%, even more preferably 0.1 to 50 mass%, still more preferably 0.5 to 45 mass%, and even more preferably 1.0 to 40 mass%, relative to the total amount (100 mass%) of the active ingredients in the pressure-sensitive adhesive composition.

[0063] (Photopolymerization initiator) When the pressure-sensitive adhesive composition contains an energy ray-curable pressure-sensitive adhesive resin as the pressure-sensitive adhesive resin, it preferably further contains a photopolymerization initiator. By including a photopolymerization initiator, the curing reaction can be sufficiently promoted even by irradiation with energy rays having a relatively low energy. Examples of photopolymerization initiators include 1-hydroxycyclohexylphenyl ketone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzyl phenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyrolnitrile, dibenzyl, diacetyl, and 8-chloroanthraquinone. These photopolymerization initiators may be used alone or in combination of two or more.

[0064] 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 even more preferably 0.05 to 2 parts by mass, relative to 100 parts by mass of the energy ray-curable adhesive resin.

[0065] (adhesive additives) The adhesive composition that is the material for forming the adhesive layer (X1) may contain, in addition to the additives mentioned above, adhesive additives that are used in general adhesives. Examples of such adhesive additives include antioxidants, softeners (plasticizers), rust inhibitors, retarders, reaction accelerators (catalysts), and ultraviolet absorbers. These adhesive additives may be used alone or in combination of two or more.

[0066] When these adhesive additives are contained, the content of each adhesive additive 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.

[0067] Here, the pressure-sensitive adhesive composition may contain at least one of a pigment and a dye, but when laser light is used in the adhesive strength reducing step (S2), it is preferable that the content of the pigment or dye that absorbs the laser light be small, from the viewpoint of laser light transmittance. Specifically, the content of the pigments and dyes that absorb laser light is preferably less than 0.1 mass %, more preferably less than 0.01 mass %, even more preferably less than 0.001 mass %, relative to the total amount of the pressure-sensitive adhesive composition, and even more preferably the pressure-sensitive adhesive composition contains no pigments or dyes.

[0068] Furthermore, when laser light is used in the adhesive strength reducing step (S2), a pressure-sensitive adhesive composition capable of preventing scattering of the laser light is preferred.

[0069] <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 also contain pressure-sensitive adhesive additives such as a crosslinking agent, a tackifier, a polymerizable compound, or a polymerization initiator, as necessary. The preferred embodiments of the composition and form of the pressure-sensitive adhesive layer (X2) are the same as those of the pressure-sensitive adhesive layer (X1). However, the compositions of the pressure-sensitive adhesive layer (X1) and the pressure-sensitive adhesive layer (X2) may be the same or different. Furthermore, the forms of the pressure-sensitive adhesive layer (X1) and the pressure-sensitive adhesive layer (X2) may be the same or different.

[0070] The thickness of each of the pressure-sensitive adhesive layer (X1) and the pressure-sensitive adhesive layer (X2) is not particularly limited, but is preferably about 1 to 50 μm, more preferably 2 to 30 μm. The thickness of the pressure-sensitive adhesive layer (X1) and the thickness of the pressure-sensitive adhesive layer (X2) may be the same or different.

[0071] <Removal material> A release material may further be provided on the adhesive surface of either or both of the adhesive layer (X1) that the adhesive sheet (X) has and the adhesive layer (X2) that the adhesive sheet (X) may have. As the release material, a release sheet with double-sided release treatment or a release sheet with one-sided release treatment is used, and examples thereof include a release material substrate coated with a release agent.

[0072] Examples of substrates for release materials include papers such as fine paper, glassine paper, and kraft paper; polyester resin films such as polyethylene terephthalate resin, polybutylene terephthalate resin, and polyethylene naphthalate resin; and plastic films such as olefin resin films such as polypropylene resin and polyethylene resin.

[0073] 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-based resins.

[0074] The thickness of the release material is not particularly limited, but is preferably 10 to 200 μm, more preferably 25 to 170 μm, and even more preferably 35 to 80 μm.

[0075] <Method for manufacturing adhesive sheet (X)> The pressure-sensitive adhesive sheet (X) can be produced by any known method without any particular limitation. For example, an organic solvent can be added to a raw material composition (hereinafter also referred to as "pressure-sensitive adhesive layer-forming composition") containing the above-mentioned components to form a solution of the raw material composition, and the solution can be applied to a substrate (Y) by a known coating method to form a coating film, which can then be dried to form a pressure-sensitive adhesive layer (X1) on the substrate (Y). Alternatively, the solution can be applied to the above-mentioned release material by a known coating method to form a coating film, which can then be dried to form a pressure-sensitive adhesive layer (X1) on the release material, and the substrate (Y) and the pressure-sensitive adhesive layer (X1) can then be bonded together to produce a pressure-sensitive adhesive sheet (X) having a laminated structure of release material / pressure-sensitive adhesive layer (X1) / substrate (Y).

[0076] Examples of the organic solvent that can be used include toluene, ethyl acetate, and methyl ethyl ketone. When an organic solvent is blended, the solids concentration of the pressure-sensitive adhesive layer-forming composition solution is preferably 10 to 80 mass %, more preferably 25 to 70 mass %, and even more preferably 45 to 65 mass %. Examples of the coating method include spin coating, spray coating, bar coating, knife coating, roll coating, roll knife coating, blade coating, die coating, and gravure coating.

[0077] [Protective film forming film] The protective film-forming film is not particularly limited, but 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 components (B) to (G) contained in the protective film-forming film will be explained below.

[0078] <Polymer component (B)> The "polymer component" means a compound having a mass average molecular weight (Mw) of 20,000 or more and having at least one type of repeating unit. By including the polymerizable component (B) in the protective film-forming film, flexibility and film-forming properties can be imparted to the protective film-forming film, and the sheet property retention can be improved. The mass average molecular weight (Mw) of the polymer component (B) is preferably from 20,000 to 3,000,000, more preferably from 50,000 to 2,000,000, and even more preferably from 100,000 to 1,500,000.

[0079] The content of the polymer component (B) is preferably 5 to 50 mass%, more preferably 8 to 40 mass%, even more preferably 10 to 30 mass%, and even more preferably 12 to 25 mass%, relative to the total amount (100 mass%) of the protective film-forming film.

[0080] As the polymer component (B), an acrylic polymer (B1) is preferred, and a non-acrylic polymer (B2) other than the acrylic polymer (B1), such as polyester, phenoxy resin, polycarbonate, polyether, polyurethane, polysiloxane, or rubber-based polymer, may also be used. These polymer components may be used alone or in combination of two or more.

[0081] (Acrylic polymer (B1)) The mass average molecular weight (Mw) of the acrylic polymer (B1) is preferably 20,000 to 3,000,000, more preferably 100,000 to 1,500,000, even more preferably 150,000 to 1,200,000, and still more preferably 250,000 to 1,000,000, from the viewpoint of imparting flexibility and film-forming properties to the protective film-forming film.

[0082] The glass transition temperature (Tg) of the acrylic polymer (B1) is preferably -60 to 50°C, more preferably -50 to 40°C, even more preferably -40 to 30°C, and even more preferably -35 to 20°C, from the viewpoint of the adhesiveness of the protective film formed from the protective film-forming film to the substrate and from the viewpoint of improving the reliability of the chip with the protective film.

[0083] Examples of the acrylic polymer (B1) include polymers containing alkyl(meth)acrylate as a main component. Specifically, an acrylic polymer containing a structural unit (b1) derived from an alkyl(meth)acrylate having an alkyl group having 1 to 18 carbon atoms is preferred, and an acrylic copolymer containing a structural unit (b2) derived from a functional group-containing monomer together with the structural unit (b1) is more preferred. The component (B1) may be used alone or in combination of two or more types. When component (B1) is a copolymer, the copolymer may be in the form of a block copolymer, a random copolymer, an alternating copolymer, or a graft copolymer.

[0084] (Structural unit (b1)) The number of carbon atoms in the alkyl group of the alkyl (meth)acrylate constituting the structural unit (b1) is preferably 1 to 18, more preferably 1 to 12, and even more preferably 1 to 8, from the viewpoint of imparting flexibility and film-forming properties to the protective film-forming film.

[0085] Examples of alkyl (meth)acrylates 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, and stearyl (meth)acrylate. These alkyl (meth)acrylates may be used alone or in combination of two or more.

[0086] Among these, alkyl(meth)acrylates having an alkyl group with 4 or more carbon atoms are preferred, alkyl(meth)acrylates having an alkyl group with 4 to 6 carbon atoms are more preferred, and butyl(meth)acrylate is even more preferred. The content of structural units derived from alkyl (meth)acrylates having an alkyl group with 4 or more carbon atoms is preferably 1 to 70 mass%, more preferably 5 to 65 mass%, and even more preferably 10 to 60 mass%, relative to all structural units (100 mass%) of the acrylic polymer (B1).

[0087] Furthermore, from the viewpoint of improving the reliability of the chip with the protective film, alkyl(meth)acrylates having an alkyl group with 1 to 3 carbon atoms are preferred, and methyl(meth)acrylate is more preferred. From the above viewpoints, the content of structural units derived from alkyl (meth)acrylates having an alkyl group having 1 to 3 carbon atoms is preferably 1 to 60 mass%, more preferably 3 to 50 mass%, and even more preferably 5 to 40 mass%, relative to all structural units (100 mass%) of the acrylic polymer (B1).

[0088] The content 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 all structural units (100% by mass) of the acrylic polymer (B1).

[0089] (Structural unit (b2)) Examples of functional group-containing monomers that constitute the structural unit (b2) include hydroxyl group-containing monomers, carboxy group-containing monomers, epoxy group-containing monomers, amino group-containing monomers, cyano group-containing monomers, keto group-containing monomers, monomers having a nitrogen atom-containing ring, and alkoxysilyl group-containing monomers. These functional group-containing monomers may be used alone or in combination of two or more. Among these, hydroxyl group-containing monomers are preferred.

[0090] Examples of the hydroxyl group-containing monomer include those exemplified in the description of the hydroxyl group-containing monomer for the pressure-sensitive adhesive layer (X1), with 2-hydroxyethyl (meth)acrylate being preferred.

[0091] Examples of the carboxy group-containing monomer include those exemplified as the carboxy group-containing monomer in the pressure-sensitive adhesive layer (X1). By using a carboxy group-containing monomer, a carboxy group is 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 between the component (C) and the component (B) is improved.

[0092] When an epoxy-based thermosetting component is used as the curable component (C) described below, the content of structural units derived from carboxyl group-containing monomers is preferably small, since the carboxyl groups react with the epoxy groups in the epoxy-based thermosetting component. When an epoxy-based thermosetting component is used as the curable component (C), the content of structural units derived from carboxyl group-containing monomers is preferably 0 to 10 mass%, more preferably 0 to 5 mass%, even more preferably 0 to 2 mass%, and still more preferably 0 mass%, relative to all structural units (100 mass%) of the acrylic polymer (A1).

[0093] Epoxy-containing monomers include epoxy-group-containing (meth)acrylic acid esters and non-acrylic epoxy-group-containing monomers. Examples of epoxy group-containing (meth)acrylic acid esters include glycidyl (meth)acrylate, β-methylglycidyl (meth)acrylate, (3,4-epoxycyclohexyl)methyl (meth)acrylate, and 3-epoxycyclo-2-hydroxypropyl (meth)acrylate. Examples of non-acrylic epoxy group-containing monomers include glycidyl crotonate and allyl glycidyl ether. Among these, epoxy group-containing (meth)acrylic acid esters are preferred, and glycidyl (meth)acrylate is more preferred. These functional group-containing monomers may be used alone or in combination of two or more.

[0094] The content of the structural units derived from the epoxy group-containing monomer is preferably 1 to 30 mass %, more preferably 5 to 27 mass %, and even more preferably 10 to 24 mass %, relative to all structural units (100 mass %) of the acrylic polymer (B1), from the viewpoint of further improving the sublimation properties of the protective film.

[0095] 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 still more preferably 20 to 40 mass%, based on all structural units (100 mass%) of the acrylic polymer (B1).

[0096] (Structural units derived from other monomers) The acrylic polymer (B1) may also contain structural units derived from monomers other than the above structural units (b1) and (b2), as long as the effects of the present invention are not impaired. Examples of other monomers include vinyl acetate, styrene, ethylene, and α-olefins.

[0097] (Non-acrylic resin (B2)) The protective film-forming film may contain a non-acrylic resin (B2) as a resin component other than the above-mentioned acrylic polymer (B1), if necessary. Examples of the non-acrylic resin (B2) include polyester, phenoxy resin, polycarbonate, polyether, polyurethane, polysiloxane, and rubber-based polymers. These resins may be used alone or in combination of two or more.

[0098] The mass average molecular weight of the non-acrylic resin (B2) is preferably 20,000 or more, more preferably 20,000 to 100,000, and even more preferably 20,000 to 80,000.

[0099] The non-acrylic resin (B2) may be used alone, but by using it in combination with the above-mentioned acrylic polymer (B1), when the adhesive sheet and the protective film-forming film are laminated together, interlayer peeling can be easily performed and the occurrence of voids, etc. can be suppressed. When the non-acrylic resin (B2) is used in combination with the above-mentioned acrylic polymer (B1), the mass ratio of the non-acrylic resin (B2) to the acrylic polymer (B1) [(B2) / (B1)] is, from the above viewpoints, preferably 1 / 99 to 60 / 40, more preferably 1 / 99 to 30 / 70.

[0100] It should be noted that the acrylic polymer (B1) in which the structural units constituting the acrylic polymer (B1) contain structural units derived from an epoxy group-containing monomer, and the phenoxy resin having an epoxy group are thermosetting, but are not considered to be the curable component (C) but are included in the concept of the polymer component (B).

[0101] <Curable component (C)> The curable component (C) plays a role in curing the protective film-forming film to form a hard protective film, and is a compound having a mass average molecular weight of less than 20,000. As the curable component (C), it is preferable to use a thermosetting component (C1) and / or an energy ray-curable component (C2), and it is more preferable to use at least a thermosetting component (C1) from the viewpoint of sufficiently progressing the curing reaction and reducing costs. The thermosetting component (C1) preferably contains at least a compound having a functional group that reacts upon heating. The energy ray-curable component (C2) contains a compound (C21) having a functional group that reacts upon irradiation with energy rays, and is polymerized and cured when irradiated with energy rays such as ultraviolet rays or electron beams. The functional groups of these curable components react with each other to form a three-dimensional network structure, thereby realizing curing. The mass 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 viewpoint of suppressing the viscosity of the composition that forms the protective film-forming film when used in combination with component (B) and improving handleability.

[0102] (Thermosetting component (C1)) The thermosetting component (C1) is preferably an epoxy-based thermosetting component. The epoxy-based thermosetting component is preferably a combination of a compound (C11) having an epoxy group and a thermosetting agent (C12).

[0103] Examples of the compound (C11) having an epoxy group (hereinafter also referred to as "epoxy compound (C11)") include epoxy compounds having two or more functional groups in the molecule, such as multifunctional epoxy resins, bisphenol A diglycidyl ether and its hydrogenated products, orthocresol novolac epoxy resins, dicyclopentadiene-type epoxy resins, biphenyl-type epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, and phenylene skeleton-type epoxy resins. These epoxy compounds (C11) may be used alone or in combination of two or more.

[0104] The content of the epoxy compound (C11) is preferably 1 to 500 parts by mass, more preferably 3 to 300 parts by mass, even more preferably 10 to 150 parts by mass, and still more preferably 20 to 120 parts by mass, relative to 100 parts by mass of the component (B).

[0105] (Thermal hardener (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 two or more functional groups capable of reacting with an epoxy group in one molecule. Examples of the functional group include a phenolic hydroxyl group, an alcoholic hydroxyl group, an amino group, a carboxyl group, and an acid anhydride group (acid anhydride structure), etc. Among these, a phenolic hydroxyl group, an amino group, or an acid anhydride group is preferred, a phenolic hydroxyl group or an amino group is more preferred, and an amino group is even more preferred.

[0106] Examples of phenolic thermosetting agents having a phenol group include polyfunctional phenolic resins, biphenols, novolac-type phenolic resins, dicyclopentadiene-type phenolic resins, Zylok-type phenolic resins, and aralkyl phenolic resins. An example of an amine-based heat curing agent having an amino group is dicyandiamide (DICY). These heat curing agents (C12) may be used alone or in combination of two or more.

[0107] The content of the heat curing 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).

[0108] (Curing accelerator (C13)) In order to adjust the rate of thermal curing of the protective film-forming film, a curing accelerator (C13) may be used. The curing accelerator (C13) is preferably used in combination with the epoxy compound (C11) as the thermosetting component (C1).

[0109] 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; and tetraphenylboron salts such as tetraphenylphosphonium tetraphenylborate and triphenylphosphine tetraphenylborate. These curing accelerators (C13) may be used alone or in combination of two or more.

[0110] 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 even 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), from the viewpoint of improving the adhesion of the protective film formed from the protective film-forming film and from the viewpoint of improving the reliability of the chip with the protective film.

[0111] (Energy ray curable component (C2)) As the energy ray-curable component (C2), a compound (C21) having a functional group that reacts upon irradiation with energy rays may be used alone, but it is preferable to use the compound (C21) in combination with a photopolymerization initiator (C22).

[0112] (Compound (C21) having a functional group that reacts upon irradiation with energy rays) Examples of the compound (C21) having a functional group that reacts upon irradiation with energy rays (hereinafter also referred to as "energy ray reactive compound (C21)") include trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, 1,4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, oligoester acrylate, urethane acrylate oligomer, epoxy acrylate, polyether acrylate, and itaconic acid oligomer. These energy ray reactive compounds (C21) may be used alone or in combination of two or more. The mass average molecular weight (Mw) of the energy ray reactive compound (C21) is preferably 100 to 30,000, more preferably 300 to 10,000.

[0113] 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, per 100 parts by mass of the component (B).

[0114] (Photopolymerization initiator (C22)) By using the photopolymerization initiator (C22) together with the above-mentioned energy ray reactive compound (C21), the polymerization curing time can be shortened, and the curing of the protective film-forming film can be promoted even with a small amount of light irradiation. Examples of the photopolymerization initiator (C22) include those mentioned 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 progressing the curing reaction and suppressing the generation of residues.

[0115] The content of component (C) is preferably 5 to 50 mass%, more preferably 8 to 40 mass%, even more preferably 10 to 30 mass%, and even more preferably 12 to 25 mass%, relative to the total amount (100 mass%) of the protective film-forming film. The content of component (C) refers to the total content of the thermosetting component (C1) containing the above-mentioned epoxy compound (C11), thermosetting agent (C12), and curing accelerator (C13), and the energy ray-curable component (C2) containing the energy ray-reactive compound (C21) and photopolymerization initiator (C22).

[0116] <Colorant (D)> The protective film-forming film preferably further contains a colorant (D). When laser light is used in the adhesive strength reducing step (S2) by including the colorant (D) in the protective film-forming film, the laser light absorptivity of the protective film can be improved by selecting the type and content of the colorant (D), and the sublimation property of the protective film can be improved. In other words, when the protective film formed by the protective film-forming film includes the colorant (D) capable of absorbing laser light, the sublimation property of the protective film can be improved.

[0117] As the colorant (D), one or more types selected from pigments and dyes can be used. The pigment may be an organic pigment or an inorganic pigment. Examples of dyes include basic dyes, acid dyes, disperse dyes, and direct dyes. Examples of black pigments include carbon black, copper oxide, iron oxide, manganese dioxide, aniline black, and activated carbon. Examples of yellow pigments include yellow lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral fast yellow, nickel titanium yellow, Naples yellow, naphthol yellow S, Hansa yellow, benzidine yellow G, benzidine yellow GR, quinoline yellow lake, permanent yellow NCG, and tartrazine lake. Examples of orange pigments include red yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, induthrene brilliant orange RK, benzidine orange G, and induthrene brilliant orange GKM. Examples of red pigments include red iron oxide, cadmium red, red lead, mercury sulfide, cadmium, permanent red 4R, lithol red, pyrozolone red, watching red, calcium salt, lake red D, brilliant carmine 6B, eosin lake, rhodamine lake B, alizarin lake, and brilliant carmine 3B. Examples of purple pigments include manganese violet, fast violet B, and methyl violet lake. Examples of blue pigments include Prussian blue, cobalt blue, alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, partially chlorinated phthalocyanine blue, fast sky blue, and indanthrene blue BC. Examples of green pigments include chrome green, chromium oxide, pigment green B, malachite green lake, and final yellow green G. Examples of dyes include nigrosine, methylene blue, rose bengal, quinoline yellow, and ultramarine blue. Here, in the adhesive strength reducing step (S2), black pigments and black dyes are preferably used from the viewpoint of facilitating improvement of laser light absorptivity over a wide wavelength range. Among black pigments, carbon black is more preferably used from the viewpoint of improving reliability of semiconductor chips. From the same viewpoint, among black dyes, nigrosine is more preferably used. These colorants (D) may be used alone or in combination of two or more.

[0118] The content of the colorant (D) is preferably 0.1 to 30 mass%, more preferably 0.5 to 25 mass%, even more preferably 1.0 to 15 mass%, and even more preferably 1.2 to 5 mass%, relative to the total amount (100 mass%) of the protective film-forming film.

[0119] <Coupling agent (E)> The protective film-forming film preferably further contains a coupling agent (E). The inclusion of the coupling agent (E) can bond the polymer component in the protective film-forming film with the adherend surface of the semiconductor chip or the filler, thereby improving adhesion and cohesion. It can also improve the water resistance of the protective film formed from the protective film-forming film without impairing the heat resistance.

[0120] As the coupling agent (E), a compound that reacts with the functional groups of component (B) or component (C) is preferred, and a silane coupling agent is more preferred. Examples of silane coupling agents include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-(methacryloxypropyl)trimethoxysilane, γ-aminopropyltrimethoxysilane, N-6-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-6-(aminoethyl)-γ-aminopropylmethyldiethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, bis(3-triethoxysilylpropyl)tetrasulfane, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, and imidazole silane. These coupling agents (E) may be used alone or in combination of two or more.

[0121] The coupling agent (E) is preferably an oligomer type coupling agent. The molecular weight of the coupling agent (E), including oligomer-type coupling agents, is preferably 100 to 15,000, more preferably 150 to 10,000, more preferably 200 to 5,000, even more preferably 250 to 3,000, and still more preferably 350 to 2,000.

[0122] 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 still more preferably 0.15 to 2 mass%, relative to the total amount (100 mass%) of the protective film-forming film.

[0123] <Inorganic filler (F)> The protective film-forming film preferably further contains an inorganic filler (F). By including the inorganic filler (F), it is possible to adjust the thermal expansion coefficient of the protective film after curing of the protective film-forming film within an appropriate range, and by optimizing the thermal expansion coefficient of the protective film after curing relative to the semiconductor chip, it is possible to improve the reliability of the semiconductor device. It is also possible to reduce the moisture absorption rate of the protective film after curing.

[0124] Examples of the inorganic filler (F) include powders of silica, alumina, talc, calcium carbonate, titanium oxide, iron oxide, silicon carbide, boron nitride, etc., beads obtained by spheronizing these, single crystal fibers, and glass fibers. These inorganic fillers (F) may be used alone or in combination of two or more. Among these, silica or alumina is preferred.

[0125] The average particle size of the inorganic filler (F) is preferably 10 nm to 50 μm, more preferably 20 nm to 30 μm, and even more preferably 30 nm to 10 μm, from the viewpoint of improving the gloss value of the protective film formed from the protective film-forming film. In the present invention, the average particle size of the inorganic filler (F) means a value measured using a laser diffraction scattering particle size distribution measuring device.

[0126] 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%, relative to the total amount (100 mass%) of the protective film-forming film.

[0127] <General-purpose additives (G)> In addition to the above, various additives may be blended into the protective film-forming film as needed. The various additives include a crosslinking agent, a leveling agent, a plasticizer, an antistatic agent, an antioxidant, an ion trapping agent, a gettering agent, a chain transfer agent, and the like.

[0128] <Method of manufacturing protective film-forming film> The method for producing the protective film-forming film is not particularly limited, and it can be produced by a known method. For example, an organic solvent is added to a raw material composition containing the above-mentioned components (hereinafter also referred to as "protective film-forming composition") to form a solution of the protective film-forming composition, and the solution is applied to the above-mentioned release sheet by a known application method to form a coating film, which is then dried to form the protective film-forming film on the release sheet, thereby producing the film.

[0129] Examples of the organic solvent that can be used include toluene, ethyl acetate, and methyl ethyl ketone. When an organic solvent is blended, the solids concentration of the solution of the protective film-forming composition is preferably 10 to 80 mass %, more preferably 20 to 70 mass %, and even more preferably 30 to 65 mass %. Examples of the coating method include spin coating, spray coating, bar coating, knife coating, roll coating, roll knife coating, blade coating, die coating, and gravure coating.

[0130] The protective film-forming film may be a single layer or may have a multi-layer structure of two or more types. 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 even more preferably 7 to 200 μm. When the protective film-forming film has a multi-layer structure, it is preferable that the total thickness (the sum of the thicknesses of each layer) is within this range.

[0131] <Method of manufacturing laminate for forming protective film> The method for producing the laminate for forming a protective film, which includes a laminate structure of the protective film-forming film and the pressure-sensitive adhesive sheet (X), is not particularly limited, and it can be produced by a known method. First, as explained in the method for producing a protective film-forming film, a protective film-forming film is formed on a release sheet. Next, the pressure-sensitive adhesive layer (X1) of the pressure-sensitive adhesive sheet (X) and the protective film-forming film formed on the release sheet are bonded together to produce a protective film-forming laminate having a laminate structure of release sheet / protective film-forming film / pressure-sensitive adhesive layer (X1) or release sheet / protective film-forming film / pressure-sensitive adhesive layer (X1) / substrate (Y).

[0132] [Method for picking up desired semiconductor chip with protective film] The method for picking up the semiconductor chip with the protective film whose adhesive strength with the adhesive layer (X1) has been reduced by step (S2) is not particularly limited, but examples include a method in which the semiconductor chip is pushed up from below through the adhesive sheet (X) with a pin or the like and picked up with a vacuum collet or the like.

[0133] In the manufacturing method according to one aspect of the present invention, the semiconductor chip with the protective film, whose adhesive strength with the pressure-sensitive adhesive layer (X1) has been reduced by the step (S2), is preferably picked up by the method described below. That is, it is preferable to carry out the following step (SP1) before or after step (S2), and to carry out the following step (SP2) after step (SP1) and after step (S2). Step (SP1): A step of attaching the adhesive layer (Z1) of a transfer sheet (Z) having the adhesive layer (Z1) to the surface of the semiconductor chips with protective films opposite the protective film side as an attachment surface, and laminating the adhesive layer (X1) and the transfer sheet (Z) via the semiconductor chips with protective films. Step (SP2): A step of separating the transfer sheet (Z) and the adhesive layer (X1), peeling off only the part of the semiconductor chips with protective films from the adhesive layer (X1), and transferring the part of the semiconductor chips with protective films to the transfer sheet (Z). In the following description, this method will also be referred to as the "transfer method."

[0134] In step (SP1), as shown in FIG. 5, the adhesive layer (Z1) of the transfer sheet (Z) having the adhesive layer (Z1) is attached to the side opposite the protective film side of a plurality of semiconductor chips 11 with protective films (including some of the semiconductor chips 11a with protective films that are desired to be peeled off), and the adhesive layer (X1) and the transfer sheet (Z) are laminated together via the plurality of semiconductor chips 11 with protective films.

[0135] <Transfer sheet (Z)> The transfer sheet (Z) has a laminated structure of a substrate (Y') and a pressure-sensitive adhesive layer (Z1). The substrate (Y') can be the same as those exemplified as the substrate (Y) of the pressure-sensitive adhesive sheet (X), and has the same thickness as the substrate (Y). The adhesive layer (Z1) may also be the same as those exemplified as the adhesive layer (X1) of the adhesive sheet (X).

[0136] Step (SP1) may be performed before or after step (S2). Either timing does not affect the adhesive strength reducing step in step (S2).

[0137] Then, step (S2) is carried out, and in a state in which the adhesive strength of some of the semiconductor chips 11a with protective films to the adhesive layer (X1) is reduced, the transfer sheet (Z) and the adhesive sheet (X) are separated as shown in Fig. 5. This allows only some of the semiconductor chips 11a with protective films to be peeled off from the adhesive sheet (X), and some of the semiconductor chips 11a with protective films can be transferred to the transfer sheet (Z).

[0138] Here, the transfer method is not limited to the above-described method. For example, after step (S2) is performed and the adhesive strength of some of the protective film-equipped semiconductor chips 11a with the adhesive layer (X1) is reduced, a porous table may be placed in contact with the surfaces of the multiple protective film-equipped semiconductor chips 11 opposite the protective film side, and some of the protective film-equipped semiconductor chips 11a may be adsorbed and transferred to the porous table. Adsorption by the porous table may be selectively performed on only some of the protective film-equipped semiconductor chips 11a whose adhesive strength has been reduced, or may be performed on the entire surface of the adhesive layer (X1). When adsorption by the porous table is performed on the entire surface of the adhesive layer (X1), the adhesive layer (X1) adsorbed to the porous table may be separated from the porous table, thereby allowing only some of the protective film-equipped semiconductor chips 11a whose adhesive strength has been reduced to be adsorbed and transferred to the porous table. The average pore size of the porous table used in this case is preferably 60 μm or less, more preferably 55 μm or less, from the viewpoint of sucking the entire surface with a weak force and adsorbing and transferring only a portion of the semiconductor chips 11a with protective film, which have a reduced adhesive strength with the adhesive layer (X1). The porosity is preferably 30% to 60%, more preferably 45% to 60%.

[0139] Furthermore, for example, after step (S2) is performed and the adhesive strength of some of the protective film-equipped semiconductor chips 11a with the adhesive layer (X1) is reduced, an electrostatic chuck may be placed in contact with the surfaces of the multiple protective film-equipped semiconductor chips 11 opposite the protective film side, and some of the protective film-equipped semiconductor chips 11a may be gripped and transferred by the electrostatic chuck. The gripping by the electrostatic chuck may be selectively performed on only some of the protective film-equipped semiconductor chips 11a with reduced adhesive strength, or may be performed on 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 may be separated from the electrostatic chuck, thereby allowing only some of the protective film-equipped semiconductor chips 11a with reduced adhesive strength to be gripped and transferred by the electrostatic chuck. In this case, from the viewpoint of gripping and transferring only some of the semiconductor chips 11a with protective film whose adhesive strength with the adhesive layer (X1) has been reduced by gripping the entire surface with a weak force, an adhesive sheet having a base material and an adhesive layer laminated thereon may be attached to the electrostatic chuck as a cushioning material to weaken the gripping force.

[0140] [Method of manufacturing semiconductor chips with protective film] A method for producing a semiconductor chip with a protective film according to one aspect of the present invention includes a step of carrying out the peeling method of the present invention including steps (S1) and (S2) or the peeling method according to one aspect of the present invention. In particular, the method for manufacturing a semiconductor chip with a protective film of the present invention is preferable because step (S1) includes a step of carrying out a peeling method of one embodiment of the present invention, which includes steps (S1-1) to (S1-2) in this order, thereby making it possible to efficiently manufacture semiconductor chips with a protective film from a semiconductor wafer with a protective film. Furthermore, it is preferable that step (S1) includes steps (S1-1) to (S1-2) in this order, and also includes a step of carrying out the above-mentioned method for manufacturing a semiconductor wafer with a protective film, since this makes it possible to efficiently manufacture semiconductor chips with a protective film from the semiconductor wafer.

[0141] [Method of manufacturing a semiconductor device including a semiconductor chip with a protective film] In this specification, the term "semiconductor device" refers to any device that can function by utilizing semiconductor characteristics, such as a processor, memory, or sensor. A method for manufacturing a semiconductor device including a semiconductor chip with a protective film, which is one aspect of the present invention, includes a step of carrying out the peeling method of the present invention, which includes steps (S1) and (S2), or a peeling method of one aspect of the present invention. Therefore, only some of the semiconductor chips with protective films can be subjected to a semiconductor device processing step. Specifically, only some of the semiconductor chips with protective films can be subjected to a step of incorporating them into a semiconductor device. For example, it becomes possible to selectively subject only good semiconductor chips with protective films to a step of incorporating them into a semiconductor device, which contributes to improving the yield of semiconductor devices. [Example]

[0142] The present invention will be specifically described with reference to the following examples, but the present invention is not limited to these examples.

[0143] Ten semiconductor chips with protective films (chip size: 1 mm x 1 mm, chip thickness: 200 μm, protective film thickness: 25 μm) were arranged in series on the adhesive layer (X1) of the adhesive sheet (X) with a chip spacing of 30 μm, and the protective film side was attached as the adhesive surface, thereby preparing an adhesive sheet (X) with multiple semiconductor chips with protective films attached.

[0144] The adhesive sheet (X) used was the following dicing tape, which had a structure in which an adhesive layer (X1) was laminated on a substrate (Y). The arithmetic mean roughness Ra of the surface of the substrate (Y) opposite to the surface on which the adhesive layer (X1) was formed was 0.1 μm. Dicing tape (Lintec, Adwill D-456H)

[0145] The protective film-forming film and curing conditions used to form the protective film of the semiconductor chip with the protective film were as follows. Protective film: ADWILL LC2850(25) ·Curing conditions: 130℃, 2 hours The protective film-forming film contains carbon black, and the protective film formed by curing the protective film-forming film is capable of absorbing laser light, which will be described later.

[0146] Of the adhesive sheet (X) having a plurality of semiconductor chips with protective films attached thereto, one semiconductor chip with protective films was irradiated with laser light from the substrate (Y) side under the following irradiation conditions. (Laser light irradiation conditions) Laser light irradiation device: EO Technics, CSM2000, solid-state green laser (wavelength: 532 nm) Frequency: 20,000Hz to 25,000Hz Scanning speed: 100mm / sec Output: 0.12W~0.82W Beam diameter: 35μm

[0147] (Experimental results) When laser light was irradiated from the substrate (Y) side toward one of the protective film-equipped semiconductor chips on an adhesive sheet (X) having multiple protective film-equipped semiconductor chips attached thereto, it was possible to visually confirm from the substrate (Y) side that an air pocket had formed at the interface between the one protective film-equipped semiconductor chip and the adhesive layer (X1), and it was found that the adhesive strength between the adhesive layer (X1) and only the one protective film-equipped semiconductor chip could be significantly reduced.On the other hand, no air pockets had formed at the interface with the adhesive layer (X1) for the remaining protective film-equipped semiconductor chips, and the adhesive strength between the adhesive layer (X1) was not reduced, and the remaining protective film-equipped semiconductor chips remained firmly attached to the adhesive layer (X1). [Explanation of symbols]

[0148] 1. Semiconductor wafer with protective film 2. Semiconductor wafers 11 Semiconductor chip with protective film 12 Semiconductor chips 13 Protective film 20 Notch 30 Laser irradiation device X adhesive sheet X1 adhesive layer Y base material Z transfer sheet Z1 adhesive layer Y' Base material

Claims

1. A method for peeling off a semiconductor chip with a protective film, comprising the following steps (S1) and (S2): Step (S1): Includes the following steps (S1-1) to (S1-2) in this order. Step (S1-1): A step of attaching a semiconductor wafer with a protective film to an adhesive layer (X1) with the protective film side as an attachment surface. Step (S1-2): Dicing the semiconductor wafer with the protective film to obtain the plurality of semiconductor chips with the protective film. Step (S2): A step of sublimating at least a part of the protective film of some of the protective film-equipped semiconductor chips among the plurality of protective film-equipped semiconductor chips to generate gas, thereby reducing the adhesive strength between the some of the protective film-equipped semiconductor chips and the pressure-sensitive adhesive layer (X1).

2. 2. The peeling method according to claim 1, wherein the semiconductor wafer with the protective film in the step (S1-1) is obtained by attaching a protective film-forming film to a semiconductor wafer and then curing the protective film-forming film.

3. The peeling method according to claim 1, wherein the step (S1-1) is performed by laminating a protective film-forming film on the pressure-sensitive adhesive layer (X1) of a pressure-sensitive adhesive sheet (X) having the pressure-sensitive adhesive layer (X1), and then attaching a semiconductor wafer to the protective film-forming film side of the protective film-forming film, and then curing the protective film-forming film.

4. The peeling method according to claim 3, wherein the pressure-sensitive adhesive sheet (X) is a dicing tape.

5. the protective film of the semiconductor chip with the protective film is a protective film capable of absorbing laser light; 5. The peeling method according to claim 1, wherein the step (S2) is performed by irradiating the laser light onto at least a part of the protective film of the part of the semiconductor chips with the protective film.

6. The peeling method according to any one of claims 1 to 5, wherein the following step (SP1) is performed before or after the step (S2), and the following step (SP2) is performed after the step (SP1) and after the step (S2). Step (SP1): A step of attaching the adhesive layer (Z1) of a transfer sheet (Z) having the adhesive layer (Z1) to the surfaces of the plurality of semiconductor chips with protective films opposite to the protective film side as an attachment surface, and laminating the adhesive layer (X1) and the transfer sheet (Z) via the plurality of semiconductor chips with protective films. Step (SP2): A step of separating the transfer sheet (Z) and the adhesive layer (X1), peeling off only the part of the semiconductor chips with protective films from the adhesive layer (X1), and transferring the part of the semiconductor chips with protective films to the transfer sheet (Z).

7. A method for producing a semiconductor chip with a protective film, comprising a step of carrying out the method according to any one of claims 1 to 6.

8. A method for manufacturing a semiconductor device including a semiconductor chip with a protective film, comprising a step of carrying out the method according to any one of claims 1 to 6.

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