Adhesive film

Abstract

To provide an adhesive film which can suppress a sealing failure such as stand-off of an electronic component of a stand-off, and occurrence of wrinkles while allowing uneven absorption equal to or higher than that of the conventional one.SOLUTION: An adhesive film 50 has a base material layer 10, an adhesive resin layer (A) which is provided on the side of a first surface 10A of the base material layer 10 and temporarily fixes an electronic component, an adhesive resin layer (B) provided on the side of a second surface 10B of the base material layer 10, and an uneven absorptive resin layer (C) which is provided between the base material layer 10 and the adhesive resin layer (A) or between the base material layer 10 and the adhesive resin layer (B), and is crosslinkable by light energy and heat energy.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an adhesive film.

Background Art

[0002] As a technology capable of reducing the size and weight of an electronic device (for example, a semiconductor device), a method for manufacturing an electronic device using an adhesive film is known. As an application example of the adhesive film in the manufacture of an electronic device, application to a sealing process can be mentioned. Specifically, in some cases, the adhesive film is applied to the steps of (i) first fixing a wafer or a chip with an adhesive film, (ii) then sealing the fixed wafer or chip with a sealing material, and (iii) thereafter peeling off the adhesive film.

[0003] As a technology related to a method for manufacturing an electronic device using an adhesive film, for example, the one described in Patent Document 1 can be mentioned. Patent Document 1 describes a heat-resistant adhesive sheet for manufacturing a semiconductor device that is used by being adhered when resin-sealing a substrate-less semiconductor chip. The heat-resistant adhesive sheet has a base material layer and an adhesive layer. The adhesive layer has an adhesive force to SUS304 of 0.5 N / 20 mm or more after bonding, and cures by the stimulus received until the completion of the resin sealing process, and has a peel force to the package of 2.0 N / 20 mm or less. A heat-resistant adhesive sheet for manufacturing a semiconductor device is described.

[0004] Further, Patent Document 2 describes an adhesive film used for temporarily fixing an electronic component when sealing the electronic component with a sealing material in the manufacturing process of an electronic device. This adhesive film includes an adhesive resin layer (A) for temporarily fixing an electronic component, an adhesive resin layer (B) that is used for attaching to a support substrate and whose adhesive force decreases due to external stimuli, and an intermediate layer (C) provided between the adhesive resin layer (A) and the adhesive resin layer (B). And the storage elastic modulus E' of the intermediate layer (C) at 120 °C is 1.0×10 5 Pa or more and 8.0×106 It is less than Pa, and the loss tangent (tanδ) of the intermediate layer (C) at 120 °C is 0.1 or less.

[0005] In addition, Patent Document 3 describes a method for manufacturing an electronic device using an adhesive film. Specifically, the method for manufacturing an electronic device described in Patent Document 3 includes a base material layer, an adhesive resin layer provided on the first surface side of the base material layer for temporarily fixing an electronic component, and an adhesive resin layer (B) provided on the second surface side of the base material layer and having an adhesive force reduced by an external stimulus. A step (1) of preparing a structure including an adhesive film, an electronic component attached to the adhesive resin layer (A) of the adhesive film, and a support substrate attached to the adhesive resin layer (B) of the adhesive film; at least one step (2) selected from a step (2-1) of reducing the moisture content in the adhesive film and a step (2-2) of reducing the moisture content in the structure; and a step (3) of sealing the electronic component with a sealing material.

[0006] In addition, Patent Document 4 also describes a method for manufacturing an electronic device. Specifically, the method for manufacturing an electronic device described in Patent Document 4 includes a base material layer, an adhesive resin layer (A) provided on the first surface side of the base material layer for temporarily fixing an electronic component, an adhesive resin layer (B) provided on the second surface side of the base material layer and having an adhesive force reduced by an external stimulus, and an unevenness-absorbing resin layer (C) provided between the base material layer and the adhesive resin layer (A) or between the base material layer and the adhesive resin layer (B). A preparation step of preparing a structure including an adhesive film, an electronic component having an uneven structure attached to the adhesive resin layer (A) of the adhesive film, and a support substrate attached to the adhesive resin layer (B) of the adhesive film; and a sealing step of sealing the electronic component with a sealing material.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

[0008] According to the studies of the present inventors, when an electronic component having an uneven structure such as a bump is arranged on an adhesive film and the electronic component is sealed with a sealing material, the position of the electronic component may shift in the horizontal direction (hereinafter also referred to as the positional deviation of the electronic component), or the sealing material may enter between the adhesive film and the electronic component. It has been clarified that there are cases where this happens.

[0009] In order to improve the above matters, for example, it is considered effective to use an adhesive film provided with a concavo-convex absorbing resin layer as described in Patent Document 4. By using an adhesive film provided with a concavo-convex absorbing resin layer, it is possible to suppress the positional deviation of the electronic component in the sealing process and the intrusion of the sealing material between the adhesive film and the electronic component.

[0010] However, as shown in FIGS. 4(a) to (c), when using an adhesive film 50A provided with a concavo-convex absorbing resin layer, when an electronic component 70A having a concavo-convex structure 75A is arranged and the electronic component is sealed with a sealing material 60A, the concavo-convex absorbing resin layer softens due to heat, and the electronic component 70A is likely to sink into the adhesive film 50A due to the pressure of the sealing material 60A. As a result, as shown in FIG. 4(d), there may be a sealing defect of the electronic component 70A such as a standoff 90 (a part of the side surface of the electronic component 70A is not sealed), or wrinkles may occur on the surface of the sealing material after sealing.

[0011] The inventors of the present invention have conducted studies to solve the above-mentioned stand-off and wrinkle problems, and found that an adhesive film having a crosslinkable unevenness-absorbing resin layer is effective. The inventors have further conducted studies and found that there is still room for improvement with respect to each of the photo-crosslinkable resin and the thermo-crosslinkable resin. That is, when the support does not transmit light, light is irradiated from the side where the chip is fixed, but since the light does not reach directly under the chip, the photo-crosslinkable intermediate layer is likely to be insufficiently cured. When a thermo-crosslinkable intermediate layer is employed, since the surface of the adhesive layer between the chips is exposed to air, radicals generated from the added curing agent are quenched by oxygen, and the intermediate layer is likely to be insufficiently cured. The present invention has been made in view of the above circumstances. One of the objects of the present invention is to provide an adhesive film that can suppress the occurrence of sealing defects and wrinkles of electronic components called stand-off while enabling unevenness absorption equal to or higher than that of the conventional art.

Means for Solving the Problems

[0012] The inventors of the present invention have intensively studied to achieve the above problems. As a result, by using an adhesive film having an unevenness-absorbing resin layer that can be crosslinked by light energy and thermal energy as the adhesive film, it has been found that the occurrence of sealing defects and wrinkles of electronic components called stand-off can be suppressed, and the present invention has been completed.

[0013] According to the present invention, the following adhesive film is provided.

[0014] [1] An adhesive film comprising a base material layer, an adhesive resin layer (A) provided on the first surface side of the base material layer and for temporarily fixing an electronic component, an adhesive resin layer (B) provided on the second surface side of the base material layer, and an unevenness-absorbing resin layer (C) provided between the base material layer and the adhesive resin layer (A) or between the base material layer and the adhesive resin layer (B) and crosslinkable by light energy and thermal energy. [2] In the pressure-sensitive adhesive film described in the above [1], A pressure-sensitive adhesive film in which the pressure-sensitive adhesive resin layer (B) is a layer whose adhesive force decreases due to external stimuli. [3] In the pressure-sensitive adhesive film described in the above [1] or [2], A pressure-sensitive adhesive film in which the unevenness-absorbing resin layer (C) contains a resin, a crosslinking agent, a photoinitiator, and a thermal initiator. [4] The pressure-sensitive adhesive film according to the above [3], wherein the photoinitiator contains an alkylphenone-based photoinitiator. [5] The pressure-sensitive adhesive film according to [3] or [4], wherein the thermal initiator contains one or more selected from aromatic ketones, onium salt compounds, organic peroxides, thio compounds, hexaarylbiimidazole compounds, ketoxime ester compounds, borate compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having a carbon-halogen bond, and azo compounds. [6] The pressure-sensitive adhesive film according to any one of [3] to [5], wherein the crosslinking agent contains one or more selected from polyfunctional (meth)acrylate compounds and isocyanate-based compounds. [7] In the pressure-sensitive adhesive film according to any one of the above [1] to [6], A pressure-sensitive adhesive film in which the unevenness-absorbing resin layer (C) is provided at least between the base material layer and the pressure-sensitive adhesive resin layer (A). [8] In the pressure-sensitive adhesive film according to any one of the above [1] to [7], The storage elastic modulus E' of the unevenness-absorbing resin layer (C') obtained by crosslinking the unevenness-absorbing resin layer (C) at 125°C is 1.0×10 6 Pa or more and 1.0×10 9 Pa or less. [9] In the pressure-sensitive adhesive film according to any one of the above [1] to [8], An adhesive film in which the thickness of the uneven absorbent resin layer (C) is 5 μm or more and 1000 μm or less.

[10] In the adhesive film according to any one of [1] to [9] above, The pressure-sensitive adhesive resin constituting the pressure-sensitive adhesive resin layer (A) is a pressure-sensitive adhesive film containing one or more selected from (meth)acrylic pressure-sensitive adhesive resins, silicone pressure-sensitive adhesive resins, urethane pressure-sensitive adhesive resins, olefin pressure-sensitive adhesive resins, and styrene pressure-sensitive adhesive resins.

[11] In the adhesive film according to any one of [1] to

[10] above, An adhesive film used for temporarily fixing an electronic component when the electronic component is sealed with a sealing material.

[12] In the adhesive film according to

[11] above, The adhesive film in which the electronic component has an uneven structure.

[13] In the adhesive film according to

[12] above, The uneven structure of the electronic component is an adhesive film including bump electrodes.

Effect of the Invention

[0015] According to the present invention, it is possible to provide a method for manufacturing an electronic component that can suppress the occurrence of sealing defects and wrinkles of the electronic component called standoff while enabling uneven absorption equal to or better than the conventional level.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same components are denoted by common reference numerals, and the description thereof will be omitted as appropriate. Also, the drawings are schematic views and do not necessarily match the actual dimensional ratios. In the specification, the description of "A to B" regarding a numerical range represents A or more and B or less unless otherwise specified. For example, 1 to 5% represents 1% or more and 5% or less. In the specification, "(meth)acryl" means acrylic, methacrylic, or both acrylic and methacrylic.

[0018] 1. Adhesive film Hereinafter, the adhesive film 50 according to the present embodiment will be described. FIG. 1 is a cross-sectional view schematically showing an example of the structure of the adhesive film 50 according to the embodiment of the present invention.

[0019] As shown in FIG. 1, the adhesive film 50 according to the present embodiment includes a base material layer 10, an adhesive resin layer (A) provided on the first surface 10A side of the base material layer 10 and for temporarily fixing an electronic component, an adhesive resin layer (B) provided on the second surface 10B side of the base material layer 10, and an unevenness-absorbing resin layer (C) provided between the base material layer 10 and the adhesive resin layer (A) or between the base material layer 10 and the adhesive resin layer (B) and crosslinkable by light energy and thermal energy. The unevenness-absorbing resin layer (C) is preferably located at least between the base material layer 10 and the adhesive resin layer (A) from the viewpoint of further improving the unevenness absorption of the adhesive film 50. When the unevenness-absorbing resin layer (C) is located between the base material layer 10 and the adhesive resin layer (A), there may be another unevenness-absorbing resin layer (C2) between the adhesive resin layer (B) and the base material layer 10. In this case, the unevenness-absorbing resin layer (C) and the unevenness-absorbing resin layer (C2) may have the same or different materials, thicknesses, etc.

[0020] As described above, according to the studies of the present inventors, by using an adhesive film provided with a concavo-convex absorbing resin layer as described in Patent Document 4 as the adhesive film, it is possible to suppress displacement of the electronic component in the sealing process and intrusion of the sealing material between the adhesive film and the electronic component. However, as shown in FIGS. 4(a) to (c), when using the adhesive film 50A provided with the concavo-convex absorbing resin layer, when arranging the electronic component 70A having the concavo-convex structure 75A and sealing the electronic component with the sealing material 60A, the concavo-convex absorbing resin layer softens due to heat, and the electronic component 70A is likely to sink into the adhesive film 50A due to the pressure of the sealing material 60A. As a result, a sealing defect of the electronic component 70A such as a standoff 90 as shown in FIG. 4(d) may occur.

[0021] The present inventors have earnestly studied in order to realize an adhesive film capable of suppressing displacement of the electronic component in the sealing process and intrusion of the sealing material between the adhesive film and the electronic component, and also capable of suppressing the occurrence of standoff in the sealing process. As a result, a base material layer 10, an adhesive resin layer (A) provided on the first surface 10A side of the base material layer 10 and for temporarily fixing the electronic component, an adhesive resin layer (B) provided on the second surface 10B side of the base material layer 10, and provided between the base material layer 10 and the adhesive resin layer (A) or between the base material layer 10 and the adhesive resin layer (B), and a concavo-convex absorbing resin layer (C) that can be crosslinked by light energy and heat energy. The adhesive film 50 provided with the above can suppress displacement of the electronic component in the sealing process and intrusion of the sealing material between the adhesive film and the electronic component, and for the first time, it has been found that the occurrence of standoff in the sealing process can be suppressed.

[0022] That is, according to the present embodiment, by using the adhesive film 50 having the unevenness-absorbing resin layer (C) that can be crosslinked by light energy and thermal energy as the adhesive film for temporarily fixing the electronic component having the unevenness structure, the adhesion of the adhesive film 50 to the electronic component having the unevenness structure is improved. Therefore, in the step of sealing the electronic component, it is possible to suppress the displacement of the position of the electronic component due to pressure or the like caused by the flow of the sealing material and the intrusion of the sealing material between the adhesive film and the electronic component. Further, after temporarily fixing the electronic component having the unevenness structure, by crosslinking and curing the unevenness-absorbing resin layer (C) by light energy and thermal energy to increase the elastic modulus, it is possible to suppress the electronic component from sinking into the adhesive film in the step of sealing the electronic component. That is, by designing the unevenness-absorbing resin layer (C) so that it is crosslinked by light energy and thermal energy and the elastic modulus changes, (i) before the light energy and thermal energy are applied, the unevenness-absorbing resin layer (C) can be sufficiently deformed according to the unevenness structure of the electronic component, and (ii) on the other hand, after the light energy and thermal energy are applied, the movement of the electronic component can be suppressed.

[0023] Furthermore, it has been found for the first time that by crosslinking and curing the unevenness-absorbing resin layer (C) by light energy and thermal energy, the generation of wrinkles on the surface portion of the sealing material after sealing can be suppressed. Although the mechanism is not clear, when irradiation is performed from the side of the electronic component 70 in FIG. 2, it is considered that the region where the light directly below the electronic component does not hit is insufficiently photocured. In addition, since the surface of the adhesive layer between the electronic components 70 and the like is exposed to air, it is considered that the active chemical species such as radicals and cations generated from the initiator are quenched by oxygen, and thus the thermal curing is less likely to occur due to so-called oxygen inhibition. At this time, by crosslinking and curing the unevenness-absorbing resin layer (C) by both light energy and thermal energy, it is considered that the crosslinking and curing of the unevenness-absorbing resin layer (C) can be performed so as to compensate for the portions that are difficult to cure by each energy. As a result, it is presumed that the generation of wrinkles on the surface of the encapsulant after encapsulation can be suppressed, which is caused by insufficient crosslinking and hardening of the concavo-convex absorbent resin layer (C).

[0024] As described above, according to the adhesive film 50 according to the present embodiment, it is possible to suppress the displacement of the electronic component in the encapsulation process and the intrusion of the encapsulant between the adhesive film and the electronic component, and it is also possible to suppress the occurrence of standoff and wrinkles in the encapsulation process.

[0025] From the viewpoint of the balance between mechanical properties and handleability, the thickness of the entire adhesive film 50 according to the present embodiment is preferably 10 μm or more and 1000 μm or less, and more preferably 20 μm or more and 500 μm or less.

[0026] The adhesive film 50 according to the present embodiment can be used, for example, for a film for temporarily fixing an electronic component when encapsulating the electronic component with an encapsulant in the manufacturing process of an electronic device. At this time, the electronic component may have a concavo-convex structure.

[0027] Next, each layer constituting the adhesive film 50 according to the present embodiment will be described.

[0028] <Base material layer> The base material layer 10 is a layer provided for the purpose of making the properties such as the handleability, mechanical properties, and heat resistance of the adhesive film 50 better. The base material layer 10 is not particularly limited, and examples thereof include resin films. Examples of the resin constituting the resin film include known thermoplastic resins. For example, polyolefins such as polyethylene, polypropylene, poly(4-methyl-1-pentene), and poly(1-butene); polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyamides such as nylon-6, nylon-66, and polymetaxylylene adipamide; polyacrylate; polymethacrylate; polyvinyl chloride; polyvinylidene chloride; polyimide; polyetherimide; ethylene-vinyl acetate copolymer; polyacrylonitrile; polycarbonate; polystyrene; ionomer; polysulfone; polyethersulfone; polyphenylene ether; and the like. One or more selected therefrom can be mentioned. Among these, from the viewpoint of excellent balance in transparency, mechanical strength, price, etc., one or more selected from polypropylene, polyethylene terephthalate, polyethylene naphthalate, polyamide, and polyimide are preferable, and at least one selected from polyethylene terephthalate and polyethylene naphthalate is more preferable.

[0029] The base material layer 10 may be a single layer or two or more layers. In addition, the form of the resin film used to form the base material layer 10 may be a stretched film or a film stretched in one axial direction or two axial directions. However, from the viewpoint of improving the mechanical strength of the base material layer 10, it is preferably a film stretched in one axial direction or two axial directions.

[0030] From the viewpoint of obtaining good film properties, the thickness of the base material layer 10 is preferably 1 μm or more and 500 μm or less, more preferably 5 μm or more and 300 μm or less, and still more preferably 10 μm or more and 250 μm or less. The base material layer 10 may be surface-treated to improve the adhesiveness with other layers. Specifically, corona treatment, plasma treatment, undercoat treatment, primer coat treatment, etc. may be performed.

[0031] <Adhesive resin layer (A)> The adhesive resin layer (A) is a layer provided on one surface side of the base material layer 10. The adhesive resin layer (A) is, for example, a layer for temporarily fixing an electronic component by contacting the surface of the electronic component when encapsulating the electronic component with an encapsulant in the manufacturing process of an electronic device.

[0032] The adhesive resin layer (A) preferably contains an adhesive resin (A1). The adhesive resin (A1) preferably contains one or more selected from (meth)acrylic adhesive resins (a), silicone adhesive resins, urethane adhesive resins, olefin adhesive resins, and styrene adhesive resins. Among these, from the viewpoint of facilitating the adjustment of adhesive force, etc., the (meth)acrylic adhesive resin (a) is preferable.

[0033] The adhesive resin layer (A) can also be a radiation crosslinkable adhesive resin layer whose adhesive force can be reduced by radiation. When the radiation crosslinkable adhesive resin layer is irradiated with radiation, it crosslinks and the adhesive force significantly decreases, so that the adhesive film 50 can be easily peeled off from the electronic component. Examples of the radiation include ultraviolet rays, electron beams, infrared rays, etc. As the radiation crosslinkable adhesive resin layer, an ultraviolet crosslinkable adhesive resin layer is preferable.

[0034] Examples of the (meth)acrylic adhesive resin (a) used for the adhesive resin layer (A) include a copolymer containing a (meth)acrylic acid alkyl ester monomer unit (a1) and a monomer unit (a2) having a functional group capable of reacting with a crosslinking agent. In the present embodiment, the (meth)acrylic acid alkyl ester means an acrylic acid alkyl ester, a methacrylic acid alkyl ester, or a mixture thereof.

[0035] The (meth)acrylic adhesive resin (a) according to the present embodiment can be obtained, for example, by copolymerizing a monomer mixture containing a (meth)acrylic acid alkyl ester monomer (a1) and a monomer (a2) having a functional group capable of reacting with a crosslinking agent.

[0036] Examples of the monomer (a1) that forms the (meth)acrylic acid alkyl ester monomer unit (a1) include (meth)acrylic acid alkyl esters having an alkyl group with about 1 to 12 carbon atoms. Preferred are (meth)acrylic acid alkyl esters having an alkyl group with 1 to 8 carbon atoms. Specifically, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, etc. may be mentioned. These may be used alone or in combination of two or more. In the (meth)acrylic pressure-sensitive adhesive resin (a) according to this embodiment, the content of the (meth)acrylic acid alkyl ester monomer unit (a1) is preferably 10% by mass or more and 98.9% by mass or less, more preferably 50% by mass or more and 97% by mass or less, and even more preferably 85% by mass or more and 95% by mass or less when the total of all monomer units in the (meth)acrylic pressure-sensitive adhesive resin (a) is 100% by mass.

[0037] Examples of the monomer (a2) that forms the monomer unit (a2) having a functional group capable of reacting with a crosslinking agent include acrylic acid, methacrylic acid, itaconic acid, mesaconic acid, citraconic acid, fumaric acid, maleic acid, itaconic acid monoalkyl ester, mesaconic acid monoalkyl ester, citraconic acid monoalkyl ester, fumaric acid monoalkyl ester, maleic acid monoalkyl ester, glycidyl acrylate, glycidyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide, methacrylamide, tertiary-butylaminoethyl acrylate, tertiary-butylaminoethyl methacrylate, etc. Preferred are acrylic acid, methacrylic acid, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide, methacrylamide, etc. These may be used alone or in combination of two or more. In the (meth)acrylic pressure-sensitive adhesive resin (a) according to this embodiment, when the total of all monomer units in the (meth)acrylic pressure-sensitive adhesive resin (a) is 100% by mass, the content of the monomer unit (a2) is preferably 1% by mass or more and 40% by mass or less, more preferably 1% by mass or more and 20% by mass or less, and still more preferably 1% by mass or more and 10% by mass or less.

[0038] The (meth)acrylic pressure-sensitive adhesive resin (a) according to this embodiment may further contain a bifunctional monomer unit (a3) or a specific comonomer (hereinafter referred to as a polymerizable surfactant) unit having the properties of a surfactant, in addition to the monomer unit (a1) and the monomer unit (a2). The polymerizable surfactant has the property of copolymerizing with the monomer (a1), the monomer (a2), and the monomer (a3), and has the action of an emulsifier when emulsion polymerization is carried out.

[0039] Examples of the monomer (a3) that forms the bifunctional monomer unit (a3) include allyl methacrylate, allyl acrylate, divinylbenzene, vinyl methacrylate, vinyl acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tetraethylene glycol di(meth)acrylate, and, for example, those having diacrylate or dimethacrylate at both ends and a propylene glycol type (e.g., manufactured by NOF Corporation, trade name: PDP-200, PDP-400, ADP-200, ADP-400), a tetramethylene glycol type (e.g., manufactured by NOF Corporation, trade name: ADT-250, ADT-850), and a mixed type thereof (e.g., manufactured by NOF Corporation, trade name: ADET-1800, ADPT-4000).

[0040] In the (meth)acrylic pressure-sensitive adhesive resin (a) according to this embodiment, when the total of all monomer units in the (meth)acrylic pressure-sensitive adhesive resin (a) is 100% by mass, the content of the monomer unit (a3) is preferably 0.1% by mass or more and 30% by mass or less, more preferably 0.1% by mass or more and 20% by mass or less, still more preferably 0.1% by mass or more and 15% by mass or less, and particularly preferably 0.1% by mass or more and 5% by mass or less.

[0041] Examples of the polymerizable surfactant include, for example, those in which a polymerizable 1-propenyl group is introduced into the benzene ring of polyoxyethylene nonylphenyl ether (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.; trade names: Aquaron RN-10, RN-20, RN-30, RN-50, etc.), those in which a polymerizable 1-propenyl group is introduced into the benzene ring of the ammonium salt of the sulfuric acid ester of polyoxyethylene nonylphenyl ether (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.; trade names: Aquaron HS-10, HS-20, HS-1025, etc.), and sulfosuccinic acid diester-based ones having a polymerizable double bond in the molecule (manufactured by Kao Corporation; trade names: Latemul S-120A, S-180A, etc.). In the (meth)acrylic pressure-sensitive adhesive resin (a) according to this embodiment, when the total of all monomer units in the (meth)acrylic pressure-sensitive adhesive resin (a) is 100% by mass, the content of the polymerizable surfactant is preferably 0.1% by mass or more and 30% by mass or less, more preferably 0.1% by mass or more and 20% by mass or less, still more preferably 0.1% by mass or more and 15% by mass or less, and particularly preferably 0.1% by mass or more and 5% by mass or less.

[0042] The (meth)acrylic pressure-sensitive adhesive resin (a) according to this embodiment may further contain, if necessary, monomer units formed from monomers having a polymerizable double bond such as vinyl acetate, acrylonitrile, and styrene.

[0043] As the polymerization reaction mechanism of the (meth)acrylic pressure-sensitive adhesive resin (a) according to the present embodiment, radical polymerization, anionic polymerization, cationic polymerization, etc. can be mentioned. Considering the production cost of the (meth)acrylic pressure-sensitive adhesive resin (a), the influence of the functional groups of the monomers, and the influence of ions on the surface of electronic components, etc., it is preferable to polymerize by radical polymerization. When polymerizing by radical polymerization reaction, as radical polymerization initiators, organic peroxides such as benzoyl peroxide, di-t-butyl peroxide, dicumyl peroxide, 3,3,5-trimethylhexanoyl peroxide, di-2-ethylhexyl peroxydicarbonate, methyl ethyl ketone peroxide, t-butyl peroxyphthalate, t-butyl peroxybenzoate, di-t-butyl peroxyacetate, t-butyl peroxyisobutyrate, t-butyl peroxy-2-hexanoate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxy-3,5,5-trimethylhexanoate, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, t-butyl peroxide, di-t-amyl peroxide; inorganic peroxides such as ammonium persulfate, potassium persulfate, sodium persulfate; and azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, 4,4'-azobis-4-cyanovaleric acid can be mentioned.

[0044] When polymerizing by the emulsion polymerization method, among these radical polymerization initiators, inorganic peroxides such as water-soluble ammonium persulfate, potassium persulfate, sodium persulfate, and azo compounds having a carboxyl group in the molecule such as water-soluble 4,4'-azobis-4-cyanovaleric acid are preferable. Considering the influence of ions on the surface of electronic components, azo compounds having a carboxyl group in the molecule such as ammonium persulfate, 4,4'-azobis-4-cyanovaleric acid, etc. are more preferable, and azo compounds having a carboxyl group in the molecule such as 4,4'-azobis-4-cyanovaleric acid, etc. are particularly preferable.

[0045] The pressure-sensitive adhesive resin layer (A) according to this embodiment preferably further contains a crosslinking agent (A2) having two or more crosslinkable functional groups in one molecule in addition to the pressure-sensitive adhesive resin (A1). The crosslinking agent (A2) having two or more crosslinkable functional groups in one molecule can be used to react with the functional groups of the pressure-sensitive adhesive resin (A1) to adjust the adhesive force and cohesive force. Examples of such crosslinking agents (A2) include epoxy compounds such as sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, neopentyl glycol diglycidyl ether, resorcin diglycidyl ether; isocyanate compounds such as tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate adduct of trimethylolpropane, polyisocyanate, diphenylmethane diisocyanate, tolylene diisocyanate; aziridine compounds such as trimethylolpropane-tri-β-aziridinylpropionate, tetramethylolmethane-tri-β-aziridinylpropionate, N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide), N,N'-hexamethylene-1,6-bis(1-aziridinecarboxamide), N,N'-toluene-2,4-bis(1-aziridinecarboxamide), trimethylolpropane-tri-β-(2-methylaziridine)propionate; tetrafunctional epoxy compounds such as N,N,N',N'-tetraglycidyl-m-xylenediamine, 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane; melamine compounds such as hexamethoxymethylol melamine. These may be used alone or in combination of two or more. Among these, it is preferable to contain one or more selected from epoxy compounds, isocyanate compounds, and aziridine compounds.

[0046] The content of the crosslinking agent (A2) is usually preferably in a range such that the number of functional groups in the crosslinking agent (A2) does not exceed the number of functional groups in the pressure-sensitive adhesive resin (A1). However, in cases where new functional groups are generated by the crosslinking reaction or the crosslinking reaction is slow, etc., it may be contained in excess as necessary. From the viewpoint of improving the balance between the heat resistance and the adhesive strength of the pressure-sensitive adhesive resin layer (A), the content of the crosslinking agent (A2) in the pressure-sensitive adhesive resin layer (A) is preferably 0.1 part by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the pressure-sensitive adhesive resin (A1).

[0047] The pressure-sensitive adhesive resin layer (A) may contain, as other components, additives such as a plasticizer and an adhesion-imparting resin. When the pressure-sensitive adhesive resin layer (A) is a radiation-crosslinkable pressure-sensitive adhesive resin layer, it may contain various additives for radiation crosslinking. When the total content of the pressure-sensitive adhesive resin (A1) and the crosslinking agent (A2) in the pressure-sensitive adhesive resin layer (A) is 100% by mass of the whole pressure-sensitive adhesive resin layer (A), it is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 90% by mass or more, and particularly preferably 95% by mass or more. Thereby, the residue of the adhesive on the electronic component side when peeling the pressure-sensitive adhesive film from the electronic component can be further suppressed.

[0048] The pressure-sensitive adhesive resin layer (A) may be a single layer or a multilayer. The thickness of the pressure-sensitive adhesive resin layer (A) is not particularly limited, but for example, it is preferably 1 μm or more and 100 μm or less, and more preferably 3 μm or more and 50 μm or less.

[0049] The pressure-sensitive adhesive resin layer (A) can be formed, for example, by applying an adhesive on the base material layer 10 or on the unevenness-absorbing resin layer (C). The adhesive may be dissolved in a solvent and applied as a coating solution, or applied as an aqueous emulsion, or directly applied as a liquid adhesive. Among them, an aqueous emulsion coating solution is preferred. Examples of the aqueous emulsion coating solution include coating solutions in which a (meth)acrylic pressure-sensitive adhesive resin (a), a silicone pressure-sensitive adhesive resin, a urethane pressure-sensitive adhesive resin, an olefin pressure-sensitive adhesive resin, a styrene pressure-sensitive adhesive resin, etc. are dispersed in water. An adhesive coating solution dissolved in an organic solvent may be used. The organic solvent is not particularly limited and may be appropriately selected from known ones in view of solubility and drying time. Examples of the organic solvent include ester-based solvents such as ethyl acetate and methyl acetate; ketone-based solvents such as acetone and MEK; aromatic solvents such as benzene, toluene, and ethylbenzene; linear or cyclic aliphatic solvents such as heptane, hexane, and cyclohexane; and alcohol-based solvents such as isopropanol and butanol. Ethyl acetate and toluene are preferred as the organic solvent. These solvents may be used alone or in combination of two or more.

[0050] As a method for applying the adhesive coating solution, conventionally known coating methods such as a roll coater method, a reverse roll coater method, a gravure roll method, a bar coat method, a comma coater method, and a die coater method can be adopted. There are no particular restrictions on the drying conditions of the applied adhesive, but generally, it is preferably dried at a temperature in the range of 80 to 200°C for 10 seconds to 10 minutes. More preferably, it is dried at 80 to 170°C for 15 seconds to 5 minutes. In order to sufficiently promote the crosslinking reaction between the crosslinking agent and the adhesive, after the drying of the adhesive coating solution is completed, it may be heated at 40 to 80°C for about 5 to 300 hours.

[0051] Further, the base material layer 10 and the adhesive resin layer (A) or the unevenness absorbing resin layer (C) may be formed by coextrusion molding, or a film-like base material layer 10 and a film-like adhesive resin layer (A) may be laminated (stacked) to form. In the examples described later, first, the adhesive resin layer (A) is formed on the surface of the separator (release film), and then the adhesive resin layer (A) is bonded to other layers to produce an adhesive film.

[0052] <Adhesive resin layer (B)> The adhesive film 50 according to the present embodiment includes an adhesive resin layer (B) on the second surface 10B side opposite to the first surface 10A of the base material layer 10. The adhesive resin layer (B) is preferably a layer whose adhesive force decreases due to external stimuli. Thereby, the adhesive film 50 can be easily peeled off from the support substrate by applying external stimuli. Here, examples of the adhesive resin layer (B) whose adhesive force decreases due to external stimuli include a heat-peelable adhesive resin layer whose adhesive force decreases upon heating, and a photo-peelable adhesive resin layer whose adhesive force decreases upon exposure to light such as radiation. That is, examples of external stimuli include light energy and thermal energy. Examples of the heat-peelable adhesive resin layer include an adhesive resin layer composed of a heat-expandable adhesive containing an adhesive resin (B1) and further containing a gas-generating component, a heat-expandable adhesive containing heat-expandable microspheres capable of expanding to reduce the adhesive force, a heat-expandable adhesive whose adhesive force decreases due to a cross-linking reaction of the adhesive component by heat, and the like.

[0053] In the present embodiment, the heat-expandable adhesive used for the adhesive resin layer (B) is an adhesive whose adhesive force decreases or is lost when heated, for example, above 150°C, preferably above 170°C. For example, a material that does not peel off at 150°C or lower or 170°C or lower and peels off above 150°C or above 170°C can be selected, and it is preferable that the adhesive film 50 has an adhesive force such that it does not peel off from the support substrate during the manufacturing process of the electronic device. Here, the fact that the adhesive force decreases or is lost when heated above 150°C or above 170°C can be evaluated, for example, by attaching the adhesive resin layer (B) side to a stainless steel plate, performing a heat treatment at 140°C for 1 hour, and then measuring the peel strength from the stainless steel plate after heating at a temperature exceeding 150°C or 170°C for 2 minutes. The specific heating temperature when heating at a temperature exceeding 150°C or 170°C is set to a temperature higher than the temperature at which gas is generated or the temperature at which the heat-expandable microspheres expand, and is appropriately set according to the type of gas generated and the heat-expandable microspheres. In the present embodiment, the loss of adhesive force means, for example, when the 180° peel strength measured under the conditions of 23°C and a tensile speed of 300 mm / min is less than 0.5 N / 25 mm.

[0054] As the gas generating component used in the heat-expandable adhesive, for example, azo compounds, azide compounds, Meldrum's acid derivatives, etc. can be used. Inorganic blowing agents such as ammonium carbonate, ammonium bicarbonate, sodium bicarbonate, ammonium nitrite, sodium borohydride, various azides, etc., and water; hydrochlorofluorocarbon compounds such as trichloromonofluoromethane, dichloromonofluoromethane; azo compounds such as azobisisobutyronitrile, azodicarbonamide, barium azodicarboxylate; hydrazine compounds such as paratoluenesulfonyl hydrazide, diphenyl sulfone-3,3'-disulfonyl hydrazide, 4,4'-oxybis(benzenesulfonyl hydrazide), allyl bis(sulfonyl hydrazide); semicarbazide compounds such as p-toluenesulfonyl semicarbazide, 4,4'-oxybis(benzenesulfonyl semicarbazide); triazole compounds such as 5-morpholyl-1,2,3,4-thiatriazole; N-nitroso compounds such as N,N'-dinitrosopentamethylenetetramine, N,N´-dimethyl-N,N'-dinitrosoterephthalamide, etc. can also be used as organic blowing agents. The gas generating component may be added to the adhesive resin (B1) or may be directly bonded to the adhesive resin (B1).

[0055] As the heat-expandable microspheres used in the heat-expandable adhesive, for example, microcapsulated blowing agents can be used. Examples of such heat-expandable microspheres include microspheres in which substances such as isobutane, propane, and pentane, which are easily gasified and expanded by heating, are encapsulated in an elastic shell. Examples of the material constituting the shell include vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, polysulfone, etc. The heat-expandable microspheres can be produced, for example, by the coacervation method, the interfacial polymerization method, etc. The heat-expandable microspheres can be added to the adhesive resin.

[0056] The content of at least one selected from the gas generating component and the thermally expandable microspheres can be appropriately set according to the expansion ratio of the heat-peelable pressure-sensitive adhesive resin layer (B), the reduction of the adhesive force, etc., and is not particularly limited. For example, with respect to 100 parts by mass of the pressure-sensitive adhesive resin (B1) in the heat-peelable pressure-sensitive adhesive resin layer (B), it is, for example, 1 part by mass or more and 150 parts by mass or less, preferably 10 parts by mass or more and 130 parts by mass or less, more preferably 12 parts by mass or more and 100 parts by mass or less. It is preferable to design such that the temperature at which gas is generated and the temperature at which the thermally expandable microspheres expand are higher than 150 °C or higher than 170 °C.

[0057] Examples of the pressure-sensitive adhesive resin (B1) constituting the heat-expandable pressure-sensitive adhesive include (meth)acrylic resins (b), urethane resins, silicone resins, polyolefin resins, polyester resins, polyamide resins, fluorine resins, styrene-diene block copolymer resins, and the like. Among these, (meth)acrylic resins (b) are preferred.

[0058] Examples of the (meth)acrylic resin (b) used for the pressure-sensitive adhesive resin layer (B) include copolymers containing (meth)acrylic acid alkyl ester monomer units (b1) and monomer units (b2) having a functional group capable of reacting with a crosslinking agent. In the present embodiment, the (meth)acrylic acid alkyl ester means an acrylic acid alkyl ester, a methacrylic acid alkyl ester, or a mixture thereof.

[0059] The (meth)acrylic pressure-sensitive adhesive resin (b) according to the present embodiment can be obtained, for example, by copolymerizing a monomer mixture containing (meth)acrylic acid alkyl ester monomers (b1) and monomers (b2) having a functional group capable of reacting with a crosslinking agent.

[0060] Examples of the monomer (b1) that forms the (meth)acrylic acid alkyl ester monomer unit (b1) include (meth)acrylic acid alkyl esters having an alkyl group with about 1 to 12 carbon atoms. Preferred are (meth)acrylic acid alkyl esters having an alkyl group with 1 to 8 carbon atoms. Specifically, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, etc. may be mentioned. These may be used alone or in combination of two or more. In the (meth)acrylic pressure-sensitive adhesive resin (b) according to the present embodiment, the content of the (meth)acrylic acid alkyl ester monomer unit (b1) is preferably 10% by mass or more and 98.9% by mass or less, more preferably 50% by mass or more and 97% by mass or less, and even more preferably 85% by mass or more and 95% by mass or less, when the total of all monomer units in the (meth)acrylic pressure-sensitive adhesive resin (b) is 100% by mass.

[0061] Examples of the monomer (b2) that forms the monomer (b2) having a functional group capable of reacting with a crosslinking agent include acrylic acid, methacrylic acid, itaconic acid, mesaconic acid, citraconic acid, fumaric acid, maleic acid, monoalkyl itaconate, monoalkyl mesaconate, monoalkyl citraconate, monoalkyl fumarate, monoalkyl maleate, glycidyl acrylate, glycidyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide, methacrylamide, tertiary-butylaminoethyl acrylate, tertiary-butylaminoethyl methacrylate, and the like. Preferably, acrylic acid, methacrylic acid, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide, methacrylamide, and the like are used. These may be used alone or in combination of two or more. In the (meth)acrylic pressure-sensitive adhesive resin (b) according to the present embodiment, when the total of all monomer units in the (meth)acrylic pressure-sensitive adhesive resin (b) is 100% by mass, the content of the monomer unit (b2) is preferably 1% by mass or more and 40% by mass or less, more preferably 1% by mass or more and 20% by mass or less, and even more preferably 1% by mass or more and 10% by mass or less.

[0062] The (meth)acrylic pressure-sensitive adhesive resin (b) according to the present embodiment may further contain a bifunctional monomer unit (b3) or a specific comonomer (hereinafter referred to as a polymerizable surfactant) unit having properties as a surfactant, in addition to the monomer unit (b1) and the monomer unit (b2). The polymerizable surfactant has a property of copolymerizing with the monomer (b1), the monomer (b2), and the monomer (b3), and has an action as an emulsifier in the case of emulsion polymerization.

[0063] As the monomer (b3) that forms the bifunctional monomer unit (b3), allyl methacrylate, allyl acrylate, divinylbenzene, vinyl methacrylate, vinyl acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tetraethylene glycol di(meth)acrylate, and, for example, those having diacrylate or dimethacrylate at both ends and a propylene glycol type main chain structure (manufactured by NOF Corporation; trade names: PDP-200, PDP-400, ADP-200, ADP-400), a tetramethylene glycol type (manufactured by NOF Corporation; trade names: ADT-250, ADT-850), and a mixed type thereof (manufactured by NOF Corporation; trade names: ADET-1800, ADPT-4000), etc. can be mentioned.

[0064] In the (meth)acrylic pressure-sensitive adhesive resin (b) according to this embodiment, the content of the monomer unit (b3) is preferably 0.1% by mass or more and 30% by mass or less, more preferably 0.1% by mass or more and 20% by mass or less, still more preferably 0.1% by mass or more and 15% by mass or less, and particularly preferably 0.1% by mass or more and 5% by mass or less when the total of all monomer units in the (meth)acrylic pressure-sensitive adhesive resin (b) is 100% by mass.

[0065] Examples of the polymerizable surfactant include, for example, those in which a polymerizable 1-propenyl group is introduced into the benzene ring of polyoxyethylene nonylphenyl ether (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.; trade names: Aquaron RN-10, RN-20, RN-30, RN-50, etc.), those in which a polymerizable 1-propenyl group is introduced into the benzene ring of the ammonium salt of the sulfuric acid ester of polyoxyethylene nonylphenyl ether (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.; trade names: Aquaron HS-10, HS-20, HS-1025, etc.), and sulfosuccinic acid diester-based ones having a polymerizable double bond in the molecule (manufactured by Kao Corporation; trade names: Latemul S-120A, S-180A, etc.). In the (meth)acrylic pressure-sensitive adhesive resin (b) according to this embodiment, when the total of all monomer units in the (meth)acrylic pressure-sensitive adhesive resin (b) is 100% by mass, the content of the polymerizable surfactant is preferably 0.1% by mass or more and 30% by mass or less, more preferably 0.1% by mass or more and 20% by mass or less, still more preferably 0.1% by mass or more and 15% by mass or less, and particularly preferably 0.1% by mass or more and 5% by mass or less.

[0066] The (meth)acrylic pressure-sensitive adhesive resin (b) according to this embodiment may further contain monomer units formed from monomers having polymerizable double bonds such as vinyl acetate, acrylonitrile, and styrene, if necessary.

[0067] Examples of the polymerization reaction mechanism of the (meth)acrylic pressure-sensitive adhesive resin (b) according to this embodiment include radical polymerization, anionic polymerization, and cationic polymerization. Considering the manufacturing cost of the (meth)acrylic pressure-sensitive adhesive resin (b), the influence of the functional groups of the monomers, and the influence of ions on the surface of electronic components, etc., it is preferable to polymerize by radical polymerization. When polymerizing by radical polymerization, as radical polymerization initiators, organic peroxides such as benzoyl peroxide, di-t-butyl peroxide, dicumyl peroxide, 3,3,5-trimethylhexanoyl peroxide, di-2-ethylhexyl peroxydicarbonate, methyl ethyl ketone peroxide, t-butyl peroxyphthalate, t-butyl peroxybenzoate, di-t-butyl peroxyacetate, t-butyl peroxyisobutyrate, t-butyl peroxy-2-hexanoate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxy-3,5,5-trimethylhexanoate, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, t-butyl peroxide, di-t-amyl peroxide; inorganic peroxides such as ammonium persulfate, potassium persulfate, sodium persulfate; and azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, 4,4'-azobis-4-cyanovaleric acid can be mentioned.

[0068] When polymerizing by the emulsion polymerization method, among these radical polymerization initiators, inorganic peroxides such as water-soluble ammonium persulfate, potassium persulfate, sodium persulfate, and azo compounds having a carboxyl group in the molecule such as water-soluble 4,4'-azobis-4-cyanovaleric acid are preferable. Considering the influence of ions on the surface of electronic components, azo compounds having a carboxyl group in the molecule such as ammonium persulfate, 4,4'-azobis-4-cyanovaleric acid are more preferable, and azo compounds having a carboxyl group in the molecule such as 4,4'-azobis-4-cyanovaleric acid are particularly preferable.

[0069] The adhesive resin layer (B) according to this embodiment preferably further contains a crosslinking agent (B2) having two or more crosslinkable functional groups in one molecule in addition to the adhesive resin (B1). The crosslinking agent (B2) having two or more crosslinkable functional groups in one molecule is used to react with the functional groups of the adhesive resin (B1) to adjust the adhesive force and cohesive force. Examples of such crosslinking agents (B2) include epoxy compounds such as sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, neopentyl glycol diglycidyl ether, resorcin diglycidyl ether; isocyanate compounds such as tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate adduct of trimethylolpropane, polyisocyanate, diphenylmethane diisocyanate, tolylene diisocyanate; aziridine compounds such as trimethylolpropane-tri-β-aziridinylpropionate, tetramethylolmethane-tri-β-aziridinylpropionate, N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide), N,N'-hexamethylene-1,6-bis(1-aziridinecarboxamide), N,N'-toluene-2,4-bis(1-aziridinecarboxamide), trimethylolpropane-tri-β-(2-methylaziridine)propionate; tetrafunctional epoxy compounds such as N,N,N',N'-tetraglycidyl-m-xylenediamine, 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane; and melamine compounds such as hexamethoxymethylol melamine. These may be used alone or in combination of two or more. Among these, it is preferable to contain one or more selected from epoxy compounds, isocyanate compounds, and aziridine compounds.

[0070] The content of the crosslinking agent (B2) is usually preferably in a range such that the number of functional groups in the crosslinking agent (B2) does not exceed the number of functional groups in the adhesive resin (B1). However, in cases where new functional groups are generated by the crosslinking reaction or the crosslinking reaction is slow, etc., it may be contained in excess as necessary. The content of the crosslinking agent (B2) in the adhesive resin layer (B) is preferably 0.1 part by mass or more and 10 parts by mass or less, more preferably 0.5 part by mass or more and 5 parts by mass or less, per 100 parts by mass of the adhesive resin (B1).

[0071] From the perspective of improving the adhesion to the support substrate, the pressure-sensitive adhesive resin layer (B) according to the present embodiment preferably contains a tackifier resin in addition to the pressure-sensitive adhesive resin (B1). Incorporating a tackifier resin into the pressure-sensitive adhesive resin layer (B) is preferable because it facilitates the adjustment of the adhesion to the support substrate near room temperature. As the tackifier resin, those having a softening point of 100°C or higher are preferred. Specific examples of the tackifier resin include rosin-based resins such as rosin derivatives treated by esterification, etc.; terpene-based resins such as α-pinene-based, β-pinene-based, dipentene-based, terpene phenol-based resins; natural rosins such as gum-based, wood-based, tall oil-based rosins; hydrogenated, disproportionated, polymerized, maleated, petroleum resins of these natural rosins; coumarone-indene resins, etc.

[0072] Among these, those having a softening point in the range of 100 to 160°C are more preferred, and those in the range of 120 to 150°C are particularly preferred. When using a tackifier resin having a softening point within the above range, not only is there less contamination and glue residue on the support substrate, but it is also possible to further improve the adhesion to the support substrate in the working environment. Furthermore, when using a polymerized rosin ester-based tackifier resin as the tackifier resin, not only is there less contamination and glue residue on the support substrate, but the adhesion to the support substrate in an environment of 80 to 130°C is improved. In the case of a heat-expandable adhesive containing thermally expandable microspheres, after the thermally expandable microspheres expand, it becomes even easier to peel from the support substrate.

[0073] The blending ratio of the tackifier resin may be appropriately selected so that the elastic modulus of the pressure-sensitive adhesive resin layer (B) can be adjusted within a desired numerical range, and there is no particular limitation. However, from the viewpoint of the elastic modulus of the pressure-sensitive adhesive resin layer (B) and the initial peel strength, it is preferably 1 to 100 parts by mass with respect to 100 parts by mass of the pressure-sensitive adhesive resin (B1). When the blending ratio of the tackifier resin is equal to or higher than the above lower limit value with respect to 100 parts by mass of the pressure-sensitive adhesive resin (B1), the adhesion to the support substrate during work tends to be good. On the other hand, when it is equal to or lower than the above upper limit value, the adhesiveness to the support substrate at room temperature tends to be good. From the viewpoints of adhesion to the support substrate and adhesiveness at room temperature, it is more preferable that the blending ratio of the tackifier resin is 2 to 50 parts by mass with respect to 100 parts by mass of the pressure-sensitive adhesive resin (B1). Further, the acid value of the tackifier resin is preferably 30 or less. When the acid value of the tackifier resin is equal to or lower than the above upper limit value, it tends to be difficult for adhesive residue to occur on the support substrate during peeling.

[0074] The pressure-sensitive adhesive resin layer (B) may contain additives such as plasticizers as other components. When the total content of the pressure-sensitive adhesive resin (B1), crosslinking agent (B2), and tackifier resin in the pressure-sensitive adhesive resin layer (B) is 100% by mass of the whole pressure-sensitive adhesive resin layer (B), it is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 90% by mass or more, and particularly preferably 95% by mass or more. Further, when the pressure-sensitive adhesive resin layer (B) is composed of a heat-expandable adhesive, when the total content of the pressure-sensitive adhesive resin (B1), crosslinking agent (B2), tackifier resin, gas generation component, and thermally expandable microspheres in the pressure-sensitive adhesive resin layer (B) is 100% by mass of the whole pressure-sensitive adhesive resin layer (B), it is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 90% by mass or more, and particularly preferably 95% by mass or more.

[0075] The pressure-sensitive adhesive resin layer (B) may be a single layer or a multi-layer. For example, by laminating two or more layers with different degrees of expansion by heating to form the pressure-sensitive adhesive resin layer (B), the pressure-sensitive adhesiveness / thermal peelability can be changed between one surface and the other surface of the pressure-sensitive adhesive resin layer (B). The thickness of the pressure-sensitive adhesive resin layer (B) is not particularly limited, but for example, it is preferably 3 μm or more and 300 μm or less, and more preferably 20 μm or more and 150 μm or less.

[0076] The pressure-sensitive adhesive resin layer (B) can be formed, for example, by a method of applying a pressure-sensitive adhesive coating liquid onto the base material layer 10, or a method of transferring the pressure-sensitive adhesive resin layer (B) formed on the separator onto the base material 10. As a method of applying the pressure-sensitive adhesive coating liquid, conventionally known coating methods such as a roll coater method, a reverse roll coater method, a gravure roll method, a bar coating method, a comma coater method, a die coater method, etc. can be adopted. There are no particular restrictions on the drying conditions of the applied pressure-sensitive adhesive, but generally, it is preferably dried at a temperature range of 80 to 200 °C for 10 seconds to 10 minutes. More preferably, it is dried at 80 to 170 °C for 15 seconds to 5 minutes. In order to sufficiently promote the crosslinking reaction between the crosslinking agent and the pressure-sensitive adhesive, after the drying of the pressure-sensitive adhesive coating liquid is completed, it may be heated at 40 to 80 °C for about 5 to 300 hours. Also, the base material layer 10 and the pressure-sensitive adhesive resin layer (B) may be formed by coextrusion molding, or may be formed by laminating (stacking) a film-like base material layer 10 and a film-like pressure-sensitive adhesive resin layer (B).

[0077] <Convexity and concavity absorbent resin layer (C)> The pressure-sensitive adhesive film 50 according to the present embodiment has a convexity and concavity absorbent resin layer (C) that can be crosslinked by light energy and thermal energy between the base material layer 10 and the pressure-sensitive adhesive resin layer (A) or between the base material layer 10 and the pressure-sensitive adhesive resin layer (B). The convexity and concavity absorbent resin layer (C) is a layer provided for the purpose of improving the followability of the pressure-sensitive adhesive film 50 to the surface on which the uneven structure of the electronic component is formed and improving the adhesion between the electronic component having the uneven structure and the pressure-sensitive adhesive film 50. Furthermore, the convexity and concavity absorbent resin layer (C) can increase the elastic modulus of the convexity and concavity absorbent resin layer (C) by crosslinking and curing with light energy and thermal energy. Thereby, in the sealing process of the electronic component, it is possible to suppress the electronic component from sinking into the pressure-sensitive adhesive film.

[0078] The resin constituting the concavo-convex absorbent resin layer (C) is not particularly limited as long as it exhibits concavo-convex absorbency. For example, a thermoplastic resin is preferable. Specifically, one or more selected from the group consisting of polyolefin resins, polystyrene resins, and (meth)acrylic resins are more preferable. From another perspective, a resin having a Shore D hardness of preferably 50 or less, more preferably 40 or less, according to the D-type Shore of ASTM D-2240 is preferable. Even when the resin constituting the concavo-convex absorbent resin layer (C) is not a thermoplastic resin, it is preferable to have the same concavo-convex absorbency as described above.

[0079] The concavo-convex absorbent resin layer (C) preferably contains a resin, a crosslinking agent, a photoinitiator that generates active chemical species by light, and a thermal initiator that generates active chemical species by heat. By including these components in the concavo-convex absorbent resin layer (C), the concavo-convex absorbent resin layer (C) can be more effectively crosslinked by light energy and thermal energy, and the elastic modulus of the concavo-convex absorbent resin layer (C) can be further improved. As a result, in the step of encapsulating an electronic component with an encapsulant, softening of the concavo-convex absorbent resin layer due to heat can be suppressed, and further, the electronic component can be more effectively prevented from sinking into the adhesive film 50 due to the pressure of the encapsulant. Note that depending on the chemical structure and reactivity of the resin and the crosslinking agent, the concavo-convex absorbent resin layer (C) may crosslink (cure) by light energy and thermal energy without necessarily containing an initiator.

[0080] The resin that can be used for forming the concavo-convex absorbent resin layer (C) is not particularly limited, and examples thereof preferably include the resins described as the adhesive resin (B1) in the aforementioned adhesive resin layer (B). In addition, the resin that can be used for forming the concavo-convex absorbent resin layer (C) is not particularly limited. For example, ethylene-α-olefin copolymers containing ethylene and α-olefins having 3 to 20 carbon atoms, high-density ethylene-based resins, low-density ethylene-based resins, medium-density ethylene-based resins, ultra-low-density ethylene-based resins, linear low-density polyethylene (LLDPE)-based resins, propylene (co)polymers, 1-butene (co)polymers, 4-methylpentene-1 (co)polymers, ethylene-cyclic olefin copolymers, ethylene-α-olefin-cyclic olefin copolymers, ethylene-α-olefin-non-conjugated polyene copolymers, ethylene-α-olefin-conjugated polyene copolymers, ethylene-aromatic vinyl copolymers, ethylene-α-olefin-aromatic vinyl copolymers and other olefin-based resins; ethylene-unsaturated carboxylic anhydride copolymers, ethylene-α-olefin-unsaturated carboxylic anhydride copolymers and other ethylene-carboxylic anhydride-based copolymers; ethylene-epoxy-containing unsaturated compound copolymers, ethylene-α-olefin-epoxy-containing unsaturated compound copolymers and other ethylene-epoxy-based copolymers; ethylene-(meth)acrylate ethyl copolymers, ethylene-(meth)acrylate methyl copolymers, ethylene-(meth)acrylate propyl copolymers, ethylene-(meth)acrylate butyl copolymers, ethylene-(meth)acrylate hexyl copolymers, ethylene-(meth)acrylate-2-hydroxyethyl copolymers, ethylene-(meth)acrylate-2-hydroxypropyl copolymers, ethylene-(meth)acrylate glycidyl copolymers and other ethylene-(meth)acrylate ester copolymers; ethylene-(meth)acrylic acid copolymers, ethylene-maleic acid copolymers, ethylene-fumaric acid copolymers, ethylene-crotonic acid copolymers and other ethylene-ethylenically unsaturated acid copolymers; ethylene-vinyl acetate copolymers, ethylene-vinyl propionate copolymers, ethylene-vinyl butyrate copolymers, ethylene-vinyl stearate copolymers and other ethylene-vinyl ester copolymers; ethylene-styrene copolymers, etc.; unsaturated carboxylic acid ester (co)polymers such as (meth)acrylate ester (co)polymers; ionomer resins such as ethylene-acrylic acid metal salt copolymers, ethylene-methacrylic acid metal salt copolymers, etc.; urethane-based resins; silicone-based resins; acrylic acid-based resins; methacrylic acid-based resins;One or more selected from cyclic olefin (co)polymers; α-olefin·aromatic vinyl compound·aromatic polyene copolymers; ethylene·α-olefin·aromatic vinyl compound; aromatic polyene copolymers; ethylene·aromatic vinyl compound·aromatic polyene copolymers; styrenic resins; acrylonitrile·butadiene·styrene copolymers; styrene·conjugated diene copolymers; acrylonitrile·styrene copolymers; acrylonitrile·ethylene·α-olefin·non-conjugated polyene·styrene copolymers; acrylonitrile·ethylene·α-olefin·conjugated polyene·styrene copolymers; methacrylic acid·styrene copolymers; ethylene terephthalate resins; fluororesins; polyester carbonates; polyvinyl chlorides; polyvinylidene chlorides; polyolefin-based thermoplastic elastomers; polystyrene-based thermoplastic elastomers; polyurethane-based thermoplastic elastomers; 1,2-polybutadiene-based thermoplastic elastomers; trans-polyisoprene-based thermoplastic elastomers; chlorinated polyethylene-based thermoplastic elastomers; liquid crystalline polyesters; polylactic acid, etc. can be used.; The concavo-convex absorbent resin layer (C) may contain only 1 resin or may contain 2 or more resins.;

[0081] As crosslinking agents that the concavo-convex absorbent resin layer (C) can contain, those that undergo a crosslinking reaction with chemical species generated from an initiator can be listed without particular limitation.; Preferred crosslinking agents include polyfunctional (meth)acrylate compounds and isocyanate compounds. More specifically, urethane (meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxy penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butanediol di(meth)acrylate, etc.; and isocyanate compounds such as tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate 3 adduct of trimethylolpropane, polyisocyanate, diphenylmethane diisocyanate, and tolylene diisocyanate. In addition, crosslinking agents include various monomers or oligomers such as urethane-based, polyether-based, polyester-based, polycarbonate-based, and polybutadiene-based. The amount of the crosslinking agent is, for example, 5 parts by mass or more and 500 parts by mass or less, preferably 40 parts by mass or more and 150 parts by mass or less, based on 100 parts by mass of a resin (base polymer) such as a (meth)acrylic polymer.

[0082] From another perspective, the unevenness-absorbing resin layer (C) may contain one or more crosslinking agents (A2) that the aforementioned pressure-sensitive adhesive resin layer (A) can contain. Specifically, the unevenness-absorbing resin layer (C) may contain an isocyanate compound. When using such a crosslinking material, the amount is, for example, 0.01 part by mass or more and 5 parts by mass or less, preferably 0.01 part by mass or more and 3 parts by mass or less, based on 100 parts by mass of the resin (base polymer).

[0083] The photoinitiator that the unevenness-absorbing resin layer (C) can contain is not particularly limited as long as it can crosslink the resin and / or crosslinking agent in the unevenness-absorbing resin layer (C) by light energy. The chemical species generated from the photoinitiator may be appropriately selected based on the functional groups possessed by the resin and / or the crosslinking agent. The chemical species generated from the photoinitiator are typically radicals or cations.

[0084] As the photoinitiator, alkylphenone-based photoinitiators, acetophenone-based photoinitiators, oxime ester-based photoinitiators, benzoin ether-based photoinitiators, acylphosphine oxide-based photoinitiators, α-ketol-based photoinitiators, aromatic sulfonyl chloride-based photoinitiators, photoactive oxime-based photoinitiators, benzoin-based photoinitiators, benzyl-based photoinitiators, benzophenone-based photoinitiators, thioxanthone-based photoinitiators, etc. can be used. The photoinitiator can be used alone or in an appropriate combination of two or more. Among these, from the viewpoints of high reactivity and low sublimation property, it is preferable to contain an alkylphenone-based photoinitiator.

[0085] Specific examples of the alkylphenone-based photoinitiator include 2-benzyl-2-(dimethylamino)-4'-morpholinobutyrophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-propan-1-one, 2-hydroxy-1-{[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one, etc. Specific examples of the acetophenone-based photoinitiator include 1-hydroxycyclohexyl-phenyl-ketone, 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, methoxyacetophenone, etc. Specific examples of oxime ester-based photoinitiators include 1,2-octanedione, 1-[4-(phenylthio)phenyl]-2-(o-benzoyloxime), ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(o-acetoxime), and the like. Specific examples of benzoin ether-based photoinitiators include benzoin ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, and substituted benzoin ethers such as anisole methyl ether. Specific examples of acylphosphine oxide-based photoinitiators include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2,4-di-n-butoxyphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, and the like. Specific examples of α-ketol-based photoinitiators include 2-methyl-2-hydroxypropiophenone, 1-[4-(2-hydroxyethyl)phenyl]-2-methylpropan-1-one, and the like. Specific examples of aromatic sulfonyl chloride-based photoinitiators include 2-naphthalenesulfonyl chloride and the like. Specific examples of photoactive oxime-based photoinitiators include 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime and the like. Specific examples of benzoin-based photoinitiators include benzoin and the like. Specific examples of benzyl-based photoinitiators include benzyl and the like. Specific examples of benzophenone-based photoinitiators include benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, α-hydroxycyclohexyl phenyl ketone, and the like. Specific examples of thioxanthone-based photoinitiators include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, dodecylthioxanthone, and the like.

[0086] As the photoinitiator, a photoinitiator that absorbs light with a wavelength of 300 nm or more (for example, light with a wavelength of 300 nm or more and 500 nm or less) and generates radicals can be preferably adopted. The photoinitiator can be used alone or in an appropriate combination of two or more.

[0087] The content of the photoinitiator in the concavo-convex absorbent resin layer (C) is preferably 0.1 part by mass or more, more preferably 0.3 part by mass or more, and even more preferably 0.5 part by mass or more with respect to 100 parts by mass of a resin (base polymer) such as a (meth)acrylic polymer. Also, from the viewpoint of storage stability, it is preferably 7 parts by mass or less, and more preferably 3 parts by mass or less.

[0088] The thermal initiator that the concavo-convex absorbent resin layer (C) can contain is not particularly limited as long as it can crosslink the resin and / or crosslinking agent in the concavo-convex absorbent resin layer (C) by thermal energy. The chemical species generated from the thermal initiator may be appropriately selected based on the functional groups of the resin and / or crosslinking agent. The chemical species generated from the thermal initiator are typically radicals or cations.

[0089] Examples of thermal initiators include aromatic ketones, onium salt compounds, organic peroxides, thio compounds, hexaarylbiimidazole compounds, ketoxime ester compounds, borate compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having a carbon-halogen bond, and azo compounds. These may be used alone or in combination of two or more. Among these, from the viewpoints of availability and handleability, azo compounds or organic peroxides are preferred, and organic peroxides are more preferred.

[0090] Examples of commercially available thermal initiators include V-70, V-65, V-601, V-59, V-40, VF-096, V-30, VAm-110, VAm-111 (manufactured by Fujifilm Wako Pure Chemical Corporation), Nipponox BW, Nipponox BMT, Peroyl TCP, Peroyl L, Peroyl 355, Peroyl SA, Perhexa HC, Perbutyl 355, Perbutyl D, Perbutyl L, Perbutyl ND, Perocta O, Perhexyl D, Perhexyl O, Perhexyl PV (manufactured by NOF Corporation), Trigonox 36-C75, Laurox, Percadox L-W75, Percadox CH-50L, Trigonox TMBH, Kayacure H, Kayabutyl H-70, Percadox BC-FF, Kayaperoxide AD, Percadox 14, Kayabutyl C, Kayabutyl D, Percadox 12-XL25, Trigonox 22-N70 (22-70E), Trigonox D-T50, Trigonox 423-C70, Kayaster CND-C70, Trigonox 23-C70, Trigonox 257-C70, Kayaster P-70, Kayaster TMPO-70, Trigonox 121, Kayaster O, Kayaster HTP-65W, Kayaster AN, Trigonox 42, Trigonox F-C50, Kayabutyl B, Kayacarbon EH, Kayacarbon I-20, Kayacarbon BIC-75, Trigonox 117, Kaylene 6-70 (manufactured by KAYAKU AKZO CORPORATION), etc.

[0091] The content of the thermal initiator in the unevenness-absorbing resin layer (C) is preferably 0.1 part by mass or more, more preferably 0.3 part by mass or more, and even more preferably 0.5 part by mass or more with respect to 100 parts by mass of a resin (base polymer) such as a (meth)acrylic polymer. Also, from the viewpoint of storage stability, it is preferably 7 parts by mass or less, and more preferably 3 parts by mass or less.

[0092] In the adhesive film 50 according to the present embodiment, the lower limit of the storage elastic modulus E' at 60°C of the unevenness-absorbing resin layer (C) before crosslinking is 1.0×10 3 Pa or more, preferably 5.0×10 3 Pa or more, from the viewpoint that the sinking of the electronic component into the adhesive film in the sealing process of the electronic component can be further suppressed. Further, in the adhesive film 50 according to the present embodiment, the upper limit of the storage elastic modulus E' at 60°C of the unevenness-absorbing resin layer (C) before crosslinking is 1.0×10 6 Pa or less, preferably 5.0×10 5 Pa or less, from the viewpoint that the unevenness on the chip surface can be effectively absorbed and the deterioration of the unevenness absorption over time due to the springback of the resin can be prevented. The storage elastic modulus E' at 60°C of the unevenness-absorbing resin layer (C) before crosslinking can be controlled within the above range, for example, by controlling the types and blending ratios of the respective components constituting the unevenness-absorbing resin layer (C).

[0093] In the adhesive film 50 according to the present embodiment, the lower limit of the storage elastic modulus E' at 125°C of the unevenness-absorbing resin layer (C') obtained by crosslinking the unevenness-absorbing resin layer (C) is 1.0×10 6 Pa or more, preferably 5.0×10 6 Pa or more, from the viewpoint that the sinking of the electronic component into the adhesive film in the sealing process of the electronic component can be further suppressed. Further, in the adhesive film 50 according to the present embodiment, the upper limit of the storage elastic modulus E' at 125°C of the unevenness-absorbing resin layer (C') is 1.0×10 9 Pa or less, preferably 1.0×10 8 Pa or less, from the viewpoint that the displacement of the electronic component in the sealing process can be further suppressed. The storage elastic modulus E' at 125°C of the unevenness-absorbing resin layer (C') can be controlled within the above range, for example, by controlling the types and blending ratios of the respective components constituting the unevenness-absorbing resin layer (C). Here, whether or not the crosslinking treatment of the concavo-convex absorbent resin layer (C) is completed can be determined, for example, by judging that the point at which the increase in the storage elastic modulus E' of the concavo-convex absorbent resin layer (C) no longer occurs even after the crosslinking treatment is the crosslinking completion point.

[0094] The thickness of the concavo-convex absorbent resin layer (C) is not particularly limited as long as it can embed the concavo-convex structure of the electronic component. For example, it is preferably 5 μm or more and 1000 μm or less, more preferably 20 μm or more and 900 μm or less, still more preferably 30 μm or more and 800 μm or less, and particularly preferably 50 μm or more and 700 μm or less.

[0095] Here, the concavo-convex structure of the electronic component preferably includes bump electrodes. When the concavo-convex structure of the electronic component includes bump electrodes, when the height of the bump electrode is H [μm] and the thickness of the concavo-convex absorbent resin layer (C) is d [μm], it is preferable that H / d is 1 or less, more preferably 0.85 or less, and still more preferably 0.7 or less. When H / d is below the above upper limit value, the thickness of the adhesive film 50 can be made thinner while improving the concavo-convex absorbency. The lower limit of H / d is not particularly limited, but is, for example, 0.01 or more. The height of the bump electrode is generally 2 μm or more and 600 μm or less.

[0096] The method for forming the concavo-convex absorbent resin layer (C) is not particularly limited, and the same method as that for the adhesive resin layer (A) and the adhesive resin layer (B) can be adopted.

[0097] <Other Layers> The adhesive film 50 according to the present embodiment may further be provided with, for example, an easy-adhesion layer or the like between the layers as long as the effects of the present embodiment are not impaired.

[0098] 2. Manufacturing Method of Electronic Device Next, the manufacturing method of the electronic device according to the present embodiment will be described. FIGS. 2 and 3 are cross-sectional views schematically showing an example of the manufacturing method of the electronic device according to the embodiment of the present invention. The manufacturing method of the electronic device according to this embodiment includes at least the following three steps. (1) An adhesive film 50 including a base material layer 10, an adhesive resin layer (A) provided on the first surface 10A side of the base material layer 10 and for temporarily fixing an electronic component 70, an adhesive resin layer (B) provided on the second surface 10B side of the base material layer 10, and an unevenness absorbing resin layer (C) provided between the base material layer 10 and the adhesive resin layer (A) or between the base material layer 10 and the adhesive resin layer (B) and crosslinkable by light energy and heat energy. A preparation step of preparing a structure 100 including an electronic component 70 having an uneven structure 75 and attached to the adhesive resin layer (A) of the adhesive film 50. (2) A crosslinking step of crosslinking the unevenness absorbing resin layer (C) by applying light energy and heat energy to the unevenness absorbing resin layer (C) in the structure 100. (3) A sealing step of sealing the electronic component 70 with a sealing material 60.

[0099] Hereinafter, each step of the manufacturing method of the electronic device according to this embodiment will be described.

[0100] ((1) Preparation step) In the preparation step, a structure 100 including an adhesive film 50 and an electronic component 70 having an uneven structure 75 and attached to the adhesive resin layer (A) of the adhesive film 50 is prepared. Here, the structure 100 preferably further includes a support substrate 80 attached to the adhesive resin layer (B) of the adhesive film 50.

[0101] Such a structure 100 can be manufactured, for example, by the following procedure. First, the adhesive film 50 is attached onto the support substrate 80 such that the adhesive resin layer (B) faces the support substrate 80 side. A protective film called a separator may be attached onto the adhesive resin layer (B), and the protective film can be peeled off and the exposed surface of the adhesive resin layer (B) can be attached to the surface of the support substrate 80. As the support substrate 80, for example, a quartz substrate, a glass substrate, a SUS substrate, or the like can be used.

[0102] Next, the structure 100 can be obtained by disposing the electronic component 70 on the adhesive resin layer (A) of the adhesive film 50. Examples of the electronic component 70 include semiconductor chips such as ICs, LSIs, discrete components, light-emitting diodes, and light-receiving elements, semiconductor panels, semiconductor packages, and the like. The surface of the electronic component 70 has, for example, an uneven structure 75 by having electrodes. In addition, the electrodes are joined to the electrodes formed on the mounting surface when mounting the electronic device on the mounting surface, for example, to form an electrical connection between the electronic device and the mounting surface (the mounting surface of a printed circuit board or the like). Examples of the electrodes include bump electrodes such as ball bumps, printed bumps, stud bumps, plated bumps, and pillar bumps. That is, the electrodes are usually convex electrodes. These bump electrodes may be used alone or in combination of two or more. In addition, the metal species constituting the bump electrodes is not particularly limited, and examples thereof include silver, gold, copper, tin, lead, bismuth, and alloys thereof. These metal species may be used alone or in combination of two or more.

[0103] ((2) Crosslinking step) Next, the unevenness-absorbing resin layer (C) in the structure 100 is crosslinked by applying light energy and heat energy to the unevenness-absorbing resin layer (C). That is, the unevenness-absorbing resin layer (C) in the structure 100 is crosslinked by irradiating light to apply light energy and applying heat energy by heating. At this time, light irradiation and heating may be performed sequentially or simultaneously. However, it is preferable to perform, in this order, a first cross-linking step of cross-linking the concavo-convex absorbing resin layer (C) by irradiating light onto the concavo-convex absorbing resin layer (C), and a second cross-linking step of further cross-linking the concavo-convex absorbing resin layer (C) by heating the concavo-convex absorbing resin layer (C). That is, in the method for manufacturing an electronic device according to the present embodiment, it is preferable that the (2) cross-linking step includes at least a first cross-linking step of cross-linking the concavo-convex absorbing resin layer (C) by irradiating light onto the structure, and a second cross-linking step of further cross-linking the concavo-convex absorbing resin layer (C) by heating the structure.

[0104] By irradiating the concavo-convex absorbing resin layer (C) with light such as ultraviolet rays, the concavo-convex absorbing resin layer (C) is cross-linked and cured. The light source used at this time is not particularly limited, but it is preferable to use a light source capable of irradiating ultraviolet rays containing a wavelength component capable of exciting a photoinitiator, and more preferably to use a light source capable of irradiating ultraviolet rays containing a component having a wavelength of less than 300 nm. Examples of such light sources include a high-pressure mercury lamp, a low-pressure mercury lamp, a metal halide lamp, a super UV lamp, and the like. The light irradiated by the above light source may contain a component having a wavelength of 300 nm or more. In the case of ultraviolet cross-linking, for example, in an environment of 0 to 60°C, using a high-pressure mercury lamp, ultraviolet rays having a main wavelength of 365 nm are irradiated at an irradiation intensity of 10 to 350 mW / cm 2 with an ultraviolet dose of 100 to 20000 mJ / cm 2 to cross-link and cure the concavo-convex absorbing resin layer (C) by irradiating the concavo-convex absorbing resin layer (C).

[0105] Also, the cross-linking method by heating the concavo-convex absorbing resin layer (C) is not limited, but preferably includes thermal cross-linking by an oven, thermal cross-linking by a hot plate, thermal cross-linking by infrared irradiation, and the like. In the case of the above thermal cross-linking, the heating temperature is, for example, 100°C to 180°C, and the heat treatment time is, for example, 10 to 180 minutes. It is preferable that the heating temperature does not exceed the temperature at which gas is generated or the temperature at which the thermally expandable microspheres expand thermally.

[0106] ((3) Sealing Process) Next, the electronic component 70 is sealed with the sealing material 60. The electronic component 70 is covered with the sealing material 60, and the sealing material 60 is cured at a temperature of, for example, 150°C or lower or 170°C or lower to seal the electronic component 70. Here, when the adhesive resin layer (B) of the adhesive film 50 contains at least one selected from gas generating components and thermally expandable microspheres, the temperature at which the sealing material 60 is cured is preferably in a range not exceeding the temperature at which gas is generated or the temperature at which the thermally expandable microspheres expand thermally. Also, the form of the sealing material 60 is not particularly limited, and for example, it is granular, sheet-like, or liquid.

[0107] As the sealing material 60, it is preferable to use one or two selected from epoxy resin-based sealing materials using epoxy resins or silicone resin-based sealing materials using silicone resins. In particular, a liquid epoxy resin-based sealing material or a silicone resin-based sealing material is preferable because the affinity of the sealing material 60 for the adhesive film 50 becomes better, and it becomes possible to seal the electronic component 70 more evenly. As such an epoxy resin-based sealing material, for example, the T693 / R4000 series, T693 / R1000 series, T693 / R5000 series, etc. manufactured by Nagase ChemteX Corporation can be used. Also, as such a silicone resin-based sealing material, for example, KMC-8400 manufactured by Shin-Etsu Chemical Co., Ltd., TSE3033, TSE3251, etc. manufactured by Momentive Performance Materials Japan Co., Ltd. can be used.

[0108] Examples of the sealing method include transfer molding, injection molding, compression molding, casting molding, etc. After sealing the electronic component 70 with the sealing material 60, the sealing material 60 is cured by heating at a temperature of, for example, 150°C or lower or 170°C or lower, and a structure 100 in which the electronic component 70 is sealed is obtained.

[0109] ((4) First Peeling Process) In the method for manufacturing an electronic device according to the present embodiment, as shown in FIG. 3(4), after the (3) sealing step, a first peeling step of peeling the support substrate 80 from the structure 100 by applying an external stimulus to reduce the adhesive force of the adhesive resin layer (B) may be further provided. The support substrate 80 can be easily removed from the adhesive film 50, for example, after sealing the electronic component 70, by heating to a temperature exceeding 150°C or a temperature exceeding 170°C to reduce the adhesive force of the adhesive resin layer (B).

[0110] ((5) Second peeling step) In the method for manufacturing an electronic device according to the present embodiment, as shown in FIG. 3(5), after the first peeling step, a second peeling step of peeling the adhesive film 50 from the electronic component 70 to obtain the electronic device 200 may be further provided. Examples of the method for peeling the adhesive film 50 from the electronic component 70 include a method of mechanically peeling, a method of reducing the adhesive force on the surface of the adhesive film 50 and then peeling, and the like.

[0111] (Other steps) In the method for manufacturing an electronic device according to the present embodiment, as shown in FIG. 3(6), a step (6) of forming a wiring layer 310 and bumps 320 on the exposed surface of the obtained electronic device 200 to obtain the electronic device 300 may be further provided.

[0112] The wiring layer 310 includes pads (not shown) which are external connection terminals formed on the outermost surface, and wirings (not shown) that electrically connect the exposed electronic component 70 and the pads. The wiring layer 310 can be formed by a conventionally known method and may have a multilayer structure.

[0113] Then, bumps 320 can be formed on the pads of the wiring layer 310 to obtain the electronic device 300. Examples of the bumps 320 include solder bumps and gold bumps. The solder bumps can be formed, for example, by placing solder balls on the pads which are the external connection terminals of the wiring layer 310 and heating to melt the solder (reflow). The gold bumps can be formed by methods such as the ball bonding method, the plating method, and the Au ball transfer method.

[0114] Also, in the method for manufacturing an electronic device according to the present embodiment, as shown in FIG. 3(7), the method may further include a step (7) of dicing the electronic device 300 to obtain a plurality of electronic devices 400. The dicing of the electronic device 300 can be performed by a known method.

[0115] As another embodiment, the method for manufacturing an electronic device according to the present embodiment may be configured without using the adhesive resin layer (B). That is, as another embodiment, the method for manufacturing an electronic device according to the present embodiment includes at least the following four steps. (1) An adhesive film 50 including a base material layer 10, an adhesive resin layer (A) provided on the first surface 10A side of the base material layer 10 and for temporarily fixing the electronic component 70, and an unevenness absorbing resin layer (C) provided between the base material layer 10 and the adhesive resin layer (A) and crosslinkable by light energy and thermal energy. A preparation step of preparing a structure 100 including the electronic component 70 having an uneven structure 75 and attached to the adhesive resin layer (A) of the adhesive film 50. (2) A first crosslinking step of crosslinking the unevenness absorbing resin layer (C) by irradiating light on the unevenness absorbing resin layer (C) in the structure 100. (3) A second crosslinking step of further crosslinking the unevenness absorbing resin layer (C) by heating the unevenness absorbing resin layer (C) in the structure 100. (4) A sealing step of sealing the electronic component 70 with a sealing material 60.

[0116] As described above, embodiments of the present invention have been described, but these are examples of the present invention, and various configurations other than the above can also be adopted.

[0117] Note that the present invention is not limited to the foregoing embodiments, and modifications, improvements, etc. within the scope that can achieve the object of the present invention are included in the present invention.

Example

[0118] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto. Details of the method for producing the adhesive film are as follows.

[0119] <Synthesis (polymerization) of an adhesive raw material for forming the concavo-convex absorbent resin layer (C), the adhesive resin layer (A) or the adhesive resin layer (B)>

[0120] (Meth)acrylic resin solution 1: 49 parts by mass of ethyl acrylate, 20 parts by mass of 2-ethylhexyl acrylate, 21 parts by mass of methyl acrylate, 10 parts by mass of glycidyl methacrylate, and 0.5 parts by mass (in terms of solid content) of a benzoyl peroxide-based polymerization initiator as a polymerization initiator were reacted at 80°C for 10 hours in 65 parts by mass of toluene and 50 parts by mass of ethyl acetate. After completion of the reaction, the obtained solution was cooled, and 25 parts by mass of xylene, 5 parts by mass of acrylic acid, and 0.5 parts by mass of tetradecyldimethylbenzylammonium chloride were added to the cooled solution, and the mixture was reacted at 85°C for 32 hours while blowing air. In this way, (meth)acrylic resin solution 1 was obtained.

[0121] (Meth)acrylic resin emulsion 1: 0.5 parts by mass of ammonium peroxydisulfate was used as a polymerization initiator, and 63 parts by mass of 2-ethylhexyl acrylate, 21 parts by mass of n-butyl acrylate, 9 parts by mass of methyl methacrylate, 3 parts by mass of 2-hydroxyethyl methacrylate, 2 parts by mass of methacrylic acid, 1 part by mass of acrylamide, 1 part by mass of polytetramethylene glycol diacrylate (manufactured by NOF Corporation, product name: Blemmer ADT-250), and 2 parts by mass of an aqueous solution of ammonium polyoxyethylene nonylpropenyl phenyl ether sulfate (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., product name: Aqualon HS-1025) were emulsion-polymerized in deionized water at 70 °C for 8 hours. After completion of the polymerization, the pH was adjusted to 7 with aqueous ammonia. In this way, (meth)acrylic resin emulsion 1 with a solid content concentration of 56.5% was obtained.

[0122] (Meth)acrylic resin emulsion 2: 0.5 parts by mass of 4,4'-azobis-4-cyanovaleric acid (manufactured by Otsuka Chemical Co., Ltd., product name: ACVA) was used as a polymerization initiator, and 74 parts by mass of butyl acrylate, 14 parts by mass of methyl methacrylate, 9 parts by mass of 2-hydroxyethyl methacrylate, 2 parts by mass of methacrylic acid, 1 part by mass of acrylamide, and 3 parts by mass of an aqueous solution of ammonium polyoxyethylene nonylpropenyl phenyl ether sulfate (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., product name: Aqualon HS-1025) were emulsion-polymerized in deionized water at 70 °C for 8 hours. After completion of the polymerization, the pH was adjusted to 7 with aqueous ammonia. As described above, (meth)acrylic resin emulsion 2 with a solid content concentration of 42.5% was obtained.

[0123] <Formulation of the adhesive coating liquid> Adhesive coating liquid B1 for forming the adhesive resin layer (B): 100 parts by mass of a (meth)acrylic resin solution 1 (solid content concentration: 45%) and 0.9 parts by mass of an isocyanate crosslinking agent (manufactured by Mitsui Chemicals, Inc., product name: Takenate D170N) (2 parts by mass based on 100 parts by mass of the pressure-sensitive adhesive resin in terms of solid content) were mixed, and 7 parts by mass of toluene and 7 parts by mass of ethyl acetate were added to prepare a pressure-sensitive adhesive coating liquid B1.

[0124] Pressure-sensitive adhesive coating liquid B2 for forming the pressure-sensitive adhesive resin layer (B): 100 parts by mass of a (meth)acrylic resin solution 1 (solid content concentration: 45%), 2.4 parts by mass of a polymerized rosin ester-based tackifier (manufactured by Arakawa Chemical Industries, Ltd., product name: Pencil D-125) (5.3 parts by mass based on 100 parts by mass of the pressure-sensitive adhesive resin in terms of solid content), 1.3 parts by mass of an isocyanate crosslinking agent (manufactured by Mitsui Chemicals, Inc., product name: Orestar P49-75S) (3.7 parts by mass based on 100 parts by mass of the pressure-sensitive adhesive resin in terms of solid content), and 7.1 parts by mass of thermally expandable microspheres (manufactured by Sekisui Chemical Co., Ltd., product name: Advance EM-503) (15.8 parts by mass based on 100 parts by mass of the pressure-sensitive adhesive resin in terms of solid content) were mixed, and 37 parts by mass of toluene and 37 parts by mass of ethyl acetate were added to prepare a pressure-sensitive adhesive coating liquid B2.

[0125] Pressure-sensitive adhesive coating liquid C1 for forming the unevenness-absorbing resin layer (C): A (meth)acrylic resin solution 1, an isocyanate crosslinking agent (manufactured by Mitsui Chemicals, Inc., product name: Orestar P49-75S), a thermal initiator (manufactured by Kayaku Nucreon Co., Ltd., organic peroxide, product name: Perkadox 12-XL25), an alkylphenone-based photoinitiator (manufactured by IGM Resins B.V., 2-benzyl-2-(dimethylamino)-4'-morpholinobutyrophenone, product name: Omnirad 369), and a polyfunctional acrylic oligomer (manufactured by Toagosei Co., Ltd., product name: Aronix M400) were mixed at the solid content mixing ratio (parts by mass) shown in Table 1 to prepare a pressure-sensitive adhesive coating liquid C1.

[0126] Pressure-sensitive adhesive coating liquid C2 for forming the unevenness-absorbing resin layer (C): (Meth)acrylic resin solution 1, isocyanate crosslinking agent (manufactured by Mitsui Chemicals, product name: Orestar P49-75S), thermal initiator (manufactured by Kayaku Nurion, organic peroxide, product name: Perkadox 12-XL25), and polyfunctional acrylic oligomer (manufactured by Toagosei Co., Ltd., product name: Aronix M400) were mixed at the solid content mixing ratio (parts by mass) shown in Table 1 to prepare adhesive coating liquid C2.

[0127] Adhesive coating liquid A for forming the pressure-sensitive adhesive resin layer (A): As shown in Table 1, 42.6 parts by mass of (meth)acrylic resin emulsion 1, 57.4 parts by mass of (meth)acrylic resin emulsion 2, 0.4 parts by mass of dimethylethanolamine, 5 parts by mass of an epoxy-based compound (manufactured by Nagase ChemteX Corporation, product name: EX-1610) as a crosslinking agent, 13 parts by mass of diethylene glycol monobutyl ether, and 20 parts by mass of H2O were mixed to prepare adhesive coating liquid A.

[0128] <Production of pressure-sensitive adhesive film> [Example 1] First, adhesive coating liquid B1 was coated on a silicone release-treated separator and dried at 120°C for 3 minutes to form a resin film. Then, this resin film was adhered to the second surface of a polyethylene terephthalate film (manufactured by Toray Industries, Inc., product name: Lumirror S10, thickness: 38 μm, corona-treated on both sides) as the base material layer to form an acrylic resin layer. Similarly, adhesive coating liquid B2 was coated on the separator and dried at 120°C for 3 minutes to form a resin film. Then, this resin film was laminated on the above acrylic resin layer. Thereby, a two-layer pressure-sensitive adhesive resin layer (B) was obtained. Thereafter, similarly, adhesive coating liquid C1 was coated on the separator and dried at 100°C for 3 minutes to form a resin film. This resin film was adhered to the first surface of the above base material layer (the surface of the base material layer opposite to the surface provided with the pressure-sensitive adhesive resin layer (B)). Thereby, a crosslinked unevenness-absorbing resin layer (C) was obtained. Furthermore, the pressure-sensitive adhesive coating liquid A was applied onto the separator and dried at 120°C for 3 minutes to obtain a resin film. This resin film was laminated onto the above crosslinked concavo-convex absorbent resin layer (C). Thereby, the pressure-sensitive adhesive resin layer (A) was obtained. As described above, an adhesive film was obtained, which includes a base material layer, a pressure-sensitive adhesive resin layer (A) provided on the first surface side of the base material layer, a pressure-sensitive adhesive resin layer (B) provided on the second surface side of the base material layer, and a concavo-convex absorbent resin layer (C) provided between the base material layer and the pressure-sensitive adhesive resin layer (A). The obtained adhesive film was heated at 60°C for 5 days.

[0129] [Comparative Example 1] An adhesive film was obtained in the same manner as in Example 1, except that the pressure-sensitive adhesive coating liquid C2 was used instead of the pressure-sensitive adhesive coating liquid C1 for forming the concavo-convex absorbent resin layer (C). (The material for forming the pressure-sensitive adhesive resin layer (B) and the method of providing the pressure-sensitive adhesive resin layer (B) are the same in Example 1 and Comparative Example 1.) Incidentally, Comparative Example 1 is different from Example 1 in that the concavo-convex absorbent resin layer does not contain an alkylphenone-based photoinitiator (Omnirad369) and is not crosslinkable by light energy.

[0130] [Evaluation] (1) Measurement of the storage elastic modulus E' of the concavo-convex absorbent resin layer (C) at 125°C Using the pressure-sensitive adhesive coating liquids C1 and C2 for forming the concavo-convex absorbent resin layer (C) used in the Examples and Comparative Examples, a concavo-convex absorbent resin layer (C) with a thickness of 40 μm was prepared separately from the adhesive film. Then, the obtained concavo-convex absorbent resin layers (C) were laminated respectively to obtain concavo-convex absorbent resin layer samples C1S and C2S with a thickness of 1 mm. Regarding the obtained concavo-convex absorbent resin layer samples C1S and C2S, 1080 mJ / cm 2Under the conditions described below, UV light with a wavelength of 300 to 600 nm was irradiated using a UV irradiator (USHIO INC., product name: UVX-02528S1AJA02). Subsequently, the structure was heated at 130 °C for 30 minutes. As a result, samples C1S' and C2S' for measuring the viscoelasticity of the unevenness-absorbing resin layer (C'), in which the unevenness-absorbing resin layer (C) was crosslinked (cured), were obtained respectively. Regarding the obtained samples C1S' and C2S' for measuring viscoelasticity, using a solid viscoelasticity measuring device (RSA-3, manufactured by TA Instruments), the solid viscoelasticity was measured and the measurement results were analyzed under the conditions of a frequency of 1 Hz, a heating rate of 5 °C / min, a strain-fixed mode with a strain of 0.05%, a chuck distance of 20 mm, and a sample width of 10 mm. Then, the storage elastic modulus E' at 125 °C of the unevenness-absorbing resin layer (C) was determined.

[0131] (2) Evaluation of wrinkles First, the adhesive resin layer (B) side of the pressure-sensitive adhesive films obtained in the examples and comparative examples was adhered onto a stainless steel plate (φ320 mm, thickness 2.0 mm) for a compression mold. Next, as electronic components, 1574 silicon mirror chips of 4.7 mm × 3.9 mm and 55 silicon chips with patterns of 3.5 mm × 3.5 mm were placed and adhered onto the adhesive resin layer (A) of the pressure-sensitive adhesive film to obtain a structure. Regarding the obtained structure, UV light with a wavelength of 300 to 600 nm was irradiated using a UV irradiator (USHIO INC., product name: UVX-02528S1AJA02) under the condition of 1080 mJ / cm 2 At this time, the UV light was irradiated from the side where the silicon chips were adhered. Subsequently, the structure was heated at 130 °C for 30 minutes. As a result, the unevenness-absorbing resin layer (C) was crosslinked (cured).

[0132] Next, using a compression molding machine, the silicon chips on the adhesive resin layer (A) were sealed by compression molding (125 °C, 400 seconds) using a liquid epoxy resin-based encapsulant (manufactured by Nagase ChemteX Corporation, product name: R4212-2C). As a result, a structure in which a sealed resin wafer (φ300 mm, thickness 550 μm) was formed on the stainless steel plate was obtained. The obtained structure was subjected to post-mold curing at 150 °C for 30 minutes. Thereafter, by heating at 190 °C for 60 seconds, the adhesive film was peeled off from the stainless-steel plate, and further the adhesive film was peeled off from the encapsulation resin wafer. Regarding the obtained encapsulation resin wafer, surface unevenness was observed using a shape analysis laser microscope (manufactured by KEYENCE Corporation, product name: VK-X1000), and wrinkles were evaluated according to the following criteria. ○ (Good): Concavities and convexities with a height difference between the concave and convex parts of 5 μm or more do not occur repeatedly. × (Bad): Concavities and convexities with a height difference between the concave and convex parts of 5 μm or more occur repeatedly.

[0133] (3) Evaluation of the standoff of electronic components in the encapsulation process First, the adhesive resin layer (B) side of the adhesive film obtained in the examples and comparative examples was adhered onto a stainless-steel plate for compression molding (φ320 mm, thickness 2.0 mm). Next, as electronic components, 1574 silicon mirror chips of 4.7 mm × 3.9 mm and 55 silicon chips with patterns of 3.5 mm × 3.5 mm were placed and adhered onto the adhesive resin layer (A) of the adhesive film to obtain a structure. Regarding the obtained structure, UV with a wavelength of 300 to 600 nm was irradiated using a UV irradiator (manufactured by USHIO INC., product name: UVX-02528S1AJA02) under the condition of 1080 mJ / cm 2 . At this time, the UV was irradiated from the side where the silicon chips were adhered. Thereafter, the structure was heated under the conditions of 130 °C for 30 minutes. Thereby, the unevenness-absorbing resin layer (C) was crosslinked (cured).

[0134] Next, using a compression molding machine, the silicon chips on the adhesive resin layer (A) were encapsulated by compression molding (125 °C, 400 seconds) using a liquid epoxy resin-based encapsulant (manufactured by Nagase ChemteX Corporation, product name: R4212-2C). Thereby, a structure in which an encapsulation resin wafer (φ300 mm, thickness 550 μm) was formed on the stainless-steel plate was obtained. The obtained structure was subjected to post-mold curing at 150 °C for 30 minutes. Thereafter, by heating at 190 °C for 60 seconds, the adhesive film was peeled off from the stainless steel plate, and further the adhesive film was peeled off from the encapsulant wafer. Regarding the obtained encapsulant wafer, with reference to the height of the surface of the encapsulant, the difference between the height of the surface of the silicon chip that is not adhered to the adhesive resin layer (A) and the height of the surface of the encapsulant was measured with a laser microscope (manufactured by KEYENCE, product name: VK-X1000) and used as the standoff. The standoff of the electronic component was evaluated based on the average value of the standoffs of 5 chips according to the following criteria. ○ (Good): The standoff is less than 10 μm × (Bad): The standoff is 10 μm or more

[0135]

Table 1

[0136] From Table 1, since the unevenness-absorbing resin layer (C) can be crosslinked by light energy and thermal energy, it was possible to suppress the occurrence of defective encapsulation and wrinkles of the electronic component called standoff.

Explanation of symbols

[0137] A Adhesive resin layer B Adhesive resin layer C Unevenness-absorbing resin layer C' Unevenness-absorbing resin layer 10 Substrate layer 10A First surface 10B Second surface 50 Adhesive film 50A Adhesive film 60 Encapsulant 60A Encapsulant 70 Electronic component 70A Electronic component 75 Uneven structure 75A Uneven structure 80 Support substrate 80A Support substrate 90 Stand-off 100 Structure 200 Electronic device 300 Electronic device 310 Wiring layer 320 Bump 400 Electronic device

Claims

1. A base material layer, a pressure-sensitive adhesive resin layer (A) provided on the first surface side of the base material layer for temporarily fixing an electronic component, a pressure-sensitive adhesive resin layer (B) provided on the second surface side of the base material layer, and provided between the base material layer and the pressure-sensitive adhesive resin layer (A) or between the base material layer and the pressure-sensitive adhesive resin layer (B), and a concavo-convex absorbent resin layer (C) that can be crosslinked by light energy and thermal energy. The concavo-convex absorbent resin layer (C) contains a resin, a crosslinking agent, a photoinitiator, and a thermal initiator. The pressure-sensitive adhesive film in which the photoinitiator contains an alkylphenone-based photoinitiator.

2. In the pressure-sensitive adhesive film according to Claim 1, The pressure-sensitive adhesive resin layer (B) is a layer in which the adhesive force decreases due to an external stimulus.

3. The pressure-sensitive adhesive film according to Claim 1 or 2, wherein the thermal initiator contains one or more selected from aromatic ketones, onium salt compounds, organic peroxides, thio compounds, hexaarylbiimidazole compounds, ketoxime ester compounds, borate compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having a carbon-halogen bond, and azo compounds.

4. The pressure-sensitive adhesive film according to any one of Claims 1 to 3, wherein the crosslinking agent contains one or more selected from polyfunctional (meth)acrylate compounds and isocyanate-based compounds.

5. In the pressure-sensitive adhesive film according to any one of Claims 1 to 4, The concavo-convex absorbent resin layer (C) is provided at least between the base material layer and the pressure-sensitive adhesive resin layer (A).

6. In the pressure-sensitive adhesive film according to any one of Claims 1 to 5, The storage elastic modulus E' at 125°C of the unevenness-absorbing resin layer (C') obtained by crosslinking the unevenness-absorbing resin layer (C) is 1.0×10 ６ Pa or more and 1.0×10 ９ Pa or less, and it is an adhesive film.

7. In the pressure-sensitive adhesive film according to any one of Claims 1 to 6, The thickness of the concavo-convex absorbent resin layer (C) is 5 μm or more and 1000 μm or less.

8. In the pressure-sensitive adhesive film according to any one of Claims 1 to 7, The pressure-sensitive adhesive resin constituting the pressure-sensitive adhesive resin layer (A) contains one or more selected from (meth)acrylic pressure-sensitive adhesive resins, silicone pressure-sensitive adhesive resins, urethane pressure-sensitive adhesive resins, olefin pressure-sensitive adhesive resins, and styrene pressure-sensitive adhesive resins.

9. In the pressure-sensitive adhesive film according to any one of Claims 1 to 8, An adhesive film used for temporarily fixing an electronic component when the electronic component is encapsulated with a sealing material.

10. In the adhesive film according to Claim 9, The adhesive film in which the electronic component has an uneven structure.

11. In the adhesive film according to Claim 10, The uneven structure of the electronic component is an adhesive film including bump electrodes.

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