Adhesive film and method for manufacturing an electronic device

Abstract

The adhesive film (50) of the present invention comprises a base layer (10), an adhesive resin layer (A) provided on the first surface (10A) side of the base layer (10), and an adhesive resin layer (B) provided on the second surface (10B) side of the base layer (10) and having adhesive strength reduced by an external stimulus, and has an integrated value (F 2.5 ) is 1.0 gf / sec or more, and the integral value of the tack strength of the adhesive resin layer (B) at a test speed of 30 mm / min and a test temperature of 130 ° C. (F 30 ) is 7.0 gf / sec or more. (Method 1) Using a tack testing machine, the probe was pressed onto the adhesive resin layer (B) for 60 seconds under the conditions of a probe load of 100 gf and a probe pressing speed of 120 mm / min. Then, the tack strength (gf) was measured at a test temperature of 130°C and test speeds of 2.5 mm / min and 30 mm / min. The horizontal axis was the measurement time and the vertical axis was the tack strength (gf). The integral value from the point where the tack strength started to rise from 0 to the point where it returned to 0 was calculated, and F was calculated for each. 2.5 and F 30 Let's say.

Description

Technical Field

[0001] The present invention relates to an adhesive film and a method for manufacturing an electronic device.

Background Art

[0002] As a technology capable of miniaturizing and lightening an electronic device (for example, a semiconductor device), a fan-out type WLP (wafer level package) has been developed. In eWLB (Embedded Wafer Level Ball Grid Array), which is one of the manufacturing methods of the fan-out type WLP, a plurality of electronic components such as semiconductor chips are temporarily fixed in a separated state on an adhesive film attached to a support substrate, and a method of collectively encapsulating the plurality of electronic components with a sealing material is adopted. Here, the adhesive film needs to be fixed to the electronic components and the support substrate in the encapsulation process and the like, and needs to be removed from the electronic components encapsulated together with the support substrate after encapsulation.

[0003] As a technology related to such a manufacturing method of the fan-out type WLP, for example, the one described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2011-134811) can be cited.

[0004] Patent Document 1 describes a heat-resistant adhesive sheet for manufacturing a semiconductor device that is used by being adhered when resin-encapsulating 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 stimulation received until the completion of the resin encapsulation 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.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] According to the studies of the present inventors, when an electronic component is placed on an adhesive film and sealed with a sealing material, it has been found that the position of the electronic component may shift (hereinafter also referred to as the positional shift of the electronic component). The present invention has been made in view of the above circumstances, and provides an adhesive film capable of suppressing the positional shift of an electronic component in a sealing process.

Means for Solving the Problems

[0007] The present inventors have intensively studied to achieve the above problems. As a result, in an adhesive film including a base material layer, an adhesive resin layer (A) provided on the first surface side of the base material layer, 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, it has been found that a measure of the integrated value of the tack force of the adhesive resin layer (B) measured by a specific method is effective as a design guideline for an adhesive film for suppressing the positional shift of an electronic component in a sealing process, and the present invention has been completed.

[0008] According to the present invention, the following adhesive film and a method for manufacturing an electronic device are provided.

[0009] [1] A base material layer, an adhesive resin layer (A) provided on the first surface side of the base material layer, 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, and the integrated value (F 2.5 ) of the tack force of the adhesive resin layer (B) at a test speed of 2.5 mm / min and a test temperature of 130°C measured by the following method 1 is 1.0 gf ·s or more, and the integrated value (F 30 ) of the tack force of the adhesive resin layer (B) at a test speed of 30 mm / min and a test temperature of 130°C is 7.0 gf·s The pressure-sensitive adhesive film described above. (Method 1) Using a tackiness tester, after pressing a probe onto the above-mentioned pressure-sensitive adhesive resin layer (B) for 60 seconds under the conditions of a probe load of 100 gf and a probe pressing speed of 120 mm / min, the tack strength (gf) is measured at test temperatures of 130 °C, test speeds of 2.5 mm / min and 30 mm / min respectively. Taking the measurement time on the horizontal axis and the tack strength (gf) on the vertical axis, the integral value from the point where the above-mentioned tack strength starts to rise from 0 to the point where it becomes 0 again is calculated respectively, and each of the above F 2.5 and the above F 30 is defined as such. [2] In the pressure-sensitive adhesive film described in the above [1], A pressure-sensitive 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. [3] In the pressure-sensitive adhesive film described in the above [1] or [2], The above-mentioned pressure-sensitive adhesive resin layer (B) is a pressure-sensitive adhesive film whose adhesive strength decreases when heated at a temperature exceeding 150 °C. [4] In the pressure-sensitive adhesive film described in the above [3], The above-mentioned pressure-sensitive adhesive resin layer (B) is a pressure-sensitive adhesive film containing at least one selected from a gas generating component and thermally expandable microspheres. [5] In the pressure-sensitive adhesive film described in any one of the above [1] to [4], The content of at least one selected from a gas generating component and thermally expandable microspheres in the above-mentioned pressure-sensitive adhesive resin layer (A) is 0.1% by mass or less when the total of the above-mentioned pressure-sensitive adhesive resin layer (A) is 100% by mass. [6] In the pressure-sensitive adhesive film described in any one of the above [1] to [5], The above-mentioned pressure-sensitive adhesive resin layer (A) is a pressure-sensitive adhesive film containing a (meth)acrylic pressure-sensitive adhesive resin. [7] The step (1) of preparing a structure including the pressure-sensitive adhesive film according to any one of [1] to [6] above, an electronic component attached to the pressure-sensitive adhesive resin layer (A) of the pressure-sensitive adhesive film, and a support substrate attached to the pressure-sensitive adhesive resin layer (B) of the pressure-sensitive adhesive film; The step (2) of encapsulating the electronic component with an encapsulant; The step (3) of reducing the adhesive force of the pressure-sensitive adhesive resin layer (B) by applying an external stimulus and peeling the support substrate from the structure; The step (4) of peeling the pressure-sensitive adhesive film from the electronic component; A method for manufacturing an electronic device comprising at least the above steps. [8] In the method for manufacturing an electronic device according to [7] above, A method for manufacturing an electronic device, wherein the encapsulant is an epoxy resin-based encapsulant.

Advantages of the Invention

[0010] According to the present invention, it is possible to provide a pressure-sensitive adhesive film capable of suppressing displacement of an electronic component in an encapsulation step.

Brief Description of the Drawings

[0011] The above-described object, as well as other objects, features, and advantages, will become more apparent from the following preferred embodiments and the accompanying drawings described below.

[0012]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0013] 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. The drawings are schematic views and do not match the actual dimensional ratios. In addition, "A to B" of the numerical range represents A or more and B or less unless otherwise specified. In the present embodiment, "(meth)acrylic" means acrylic, methacrylic, or both acrylic and methacrylic.

[0014] 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.

[0015] 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 an adhesive resin layer (B) provided on the second surface 10B side of the base material layer 10 and having a reduced adhesive force due to an external stimulus. The integrated value (F 2.5 ) of the tack force of the adhesive resin layer (B) at a test speed of 2.5 mm / min and a test temperature of 130 ° C. measured by the following method 1 is 1.0 gf ·s or more, and the integrated value (F 30 ) of the tack force of the adhesive resin layer (B) at a test speed of 30 mm / min and a test temperature of 130 ° C. is 7.0 gf ·s or more. (Method 1) Using a tacking tester, after pressing the probe on the adhesive resin layer (B) for 60 seconds under the conditions of a probe load of 100 gf and a probe pushing speed of 120 mm / min, the tack strength (gf) is measured at a test temperature of 130 ° C., test speeds of 2.5 mm / min and 30 mm / min, respectively. Taking the measurement time on the horizontal axis and the tack strength (gf) on the vertical axis, the integrated value from the point where the tack strength starts to rise from 0 to the point where it becomes 0 again is calculated, and they are respectively F 2.5 and F 30 .

[0016] As described above, according to the studies of the present inventors, it has been clarified that when an electronic component is placed on an adhesive film and sealed with a sealing material, displacement of the electronic component may occur.

[0017] The present inventors have intensively studied to realize an adhesive film capable of suppressing displacement of an electronic component in a sealing process. As a result, in 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 an adhesive resin layer (B) provided on the second surface 10B side of the base material layer 10 and having an adhesive force reduced by an external stimulus, the integrated value (F 2.5 ) of the tack force of the adhesive resin layer (B) and the integrated value (F 30 ) of the tack force measured by the above method 1 are first found to be effective as design guidelines for an adhesive film for suppressing displacement of an electronic component in a sealing process. That is, the adhesive film 50 according to the present embodiment can suppress displacement of an electronic component in a sealing process by setting the integrated value (F 2.5 ) of the tack force of the adhesive resin layer (B) and the integrated value (F 30 ) to be equal to or greater than the above lower limit values, respectively. Although the reason why displacement of an electronic component in a sealing process can be suppressed by using the adhesive film 50 according to the present embodiment is not clear, the following reasons are considered. First, according to the studies of the present inventors, in the process of sealing an electronic component, outgas derived from moisture and residual volatile components contained in the adhesive film, particularly outgas derived from moisture and residual volatile components contained in the adhesive resin layer on the side attached to the support substrate, causes the adhesive film to float, and as a result, displacement of the electronic component occurs. The present inventors further studied based on the above findings. As a result, the integrated value (F 2.5 ) of the tack force of the adhesive resin layer (B) and the integrated value (F 30An adhesive film in which the integral value (F 2.5 ) and the integral value (F 30 ) of the tack force are each equal to or greater than the above lower limit value is less likely to float due to outgassing derived from moisture and residual volatile components contained in the adhesive film, particularly outgassing derived from moisture and residual volatile components contained in the adhesive resin layer on the side attached to the support substrate, and as a result, it has been clarified that displacement of the electronic component is less likely to occur. That is, the adhesive film in which the integral value (F

[0018] ) and the integral value (F 2.5 ) of the tack force of the adhesive resin layer (B) are each equal to or greater than the above lower limit value is less likely to be adversely affected by outgassing derived from moisture and residual volatile components in the sealing process, and as a result, it is considered that displacement of the electronic component in the sealing process can be suppressed. ·s In the adhesive film 50 according to the present embodiment, the lower limit of the integral value (F ·s ) of the tack force is 1.0 gf ·s or more, but from the viewpoint of further suppressing the displacement of the electronic component in the sealing process, 1.5 gf ·s or more is preferable, 2.0 gf or more is more preferable, and 2.5 gf 2.5 ) of the tack force is preferably 50.0 gf ·s or less, more preferably 35.0 gf ·s or less, further preferably 25.0 gf ·s or less, even more preferably 15 gf ·s or less, and particularly preferably 7.5 gf ·s or less, from the viewpoint of effectively suppressing the adhesive residue on the support substrate side when peeling the support substrate from the adhesive resin layer (B) or improving the desorbability from the support substrate.

[0019] In the adhesive film 50 according to the present embodiment, the lower limit of the integral value (F 30 ) of the tack force is 7.0 gf ·s or more, but from the viewpoint of further suppressing the displacement of the electronic component in the sealing process, 8.0 gf·s is preferable, and 9.0 gf or more ·s is more preferable, and 10.0 gf or more ·s is even more preferable. Also, in the adhesive film 50 according to the present embodiment, the upper limit of the integrated value (F 30 ) of the tack force is 150.0 gf or less, 100.0 gf or less is more preferable, 80.0 gf or less is even more preferable, 50.0 gf or less is still more preferable, 25.0 gf or less is even more preferable, and 25.0 gf or less is particularly preferable, from the viewpoint of effectively suppressing the adhesive residue on the support substrate side when peeling the support substrate from the pressure-sensitive adhesive resin layer (B) or improving the desorbability from the support substrate. ·s is preferable, and 100.0 gf or less ·s is more preferable, and 80.0 gf or less ·s is even more preferable, and 50.0 gf or less ·s is even more preferably, and 25.0 gf or less ·s is particularly preferable.

[0020] In the adhesive film 50 according to the present embodiment, the integrated value (F 2.5 ) of the tack force and the integrated value (F 30 ) of the tack force can be controlled, for example, by controlling the types and blending ratios of the respective components constituting the pressure-sensitive adhesive resin layer (B), or the types and content ratios of the respective monomers in the pressure-sensitive adhesive resin constituting the pressure-sensitive adhesive resin layer (B). More specifically, it is presumed that the hardness of the pressure-sensitive adhesive resin layer (B) and the volatile components contained in the pressure-sensitive adhesive resin layer (B) have an influence, and the amount of the crosslinking agent (B2) and the amount of moisture and residual solvent contained in the adhesive film 50 (particularly the pressure-sensitive adhesive resin layer (B)) tend to have an influence. Therefore, by controlling the amount and functional group number of the crosslinking agent (B2) described later, the amount of moisture contained in the adhesive film 50 (particularly the pressure-sensitive adhesive resin layer (B)), and the amount of residual volatile components such as residual solvent, the integrated value (F 2.5 ) of the tack force and the integrated value (F 30 ) of the tack force can be controlled within the above ranges.

[0021] The thickness of the entire adhesive film 50 according to the present embodiment is preferably 10 μm or more and 1000 μm or less, more preferably 20 μm or more and 500 μm or less, from the viewpoint of the balance between mechanical properties and handleability.

[0022] The adhesive film 50 according to this embodiment can be used, for example, as a film for temporarily fixing electronic components in the manufacturing process of electronic devices, and in particular, can be suitably used as a film for temporarily fixing electronic components in the manufacturing process of fan-out type WLP.

[0023] Next, each layer constituting the adhesive film 50 according to this embodiment will be described.

[0024] <Base material layer> The base material layer 10 is a layer provided for the purpose of making the handling properties, mechanical properties, heat resistance and other properties of the adhesive film 50 better. The base material layer 10 is not particularly limited, and examples thereof include resin films. As the resin constituting the resin film, known thermoplastic resins can be used. For example, polyolefins such as polyethylene, polypropylene, poly(4-methyl-1-pentene), poly(1-butene); polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate; polyamides such as nylon-6, nylon-66, polymetaxylylene adipamide; polyacrylate; polymethacrylate; polyvinyl chloride; polyvinylidene chloride; polyimide; polyetherimide; ethylene-vinyl acetate copolymer; polyacrylonitrile; polycarbonate; polystyrene; ionomer; polysulfone; polyethersulfone; polyphenylene ether, etc. One or more selected from these can be mentioned. Among these, from the viewpoint of excellent balance of transparency, mechanical strength, price, etc., one or more selected from polypropylene, polyethylene terephthalate, polyethylene naphthalate, polyamide, polyimide are preferable, and at least one selected from polyethylene terephthalate, polyethylene naphthalate is more preferable.

[0025] The base material layer 10 may be a single layer or two or more kinds of layers. In addition, as the form of the resin film used to form the base material layer 10, it may be a stretched film, or a film stretched in a uniaxial direction or a biaxial direction. However, from the perspective of improving the mechanical strength of the base material layer 10, it is preferably a film stretched in a uniaxial direction or a biaxial direction.

[0026] From the perspective 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 even more preferably 10 μm or more and 250 μm or less. The base material layer 10 may be surface-treated in order to improve the adhesiveness with other layers. Specifically, corona treatment, plasma treatment, undercoat treatment, primer coat treatment, etc. may be performed.

[0027] <Adhesive resin layer (A)> The adhesive resin layer (A) is a layer provided on one surface side of the base material layer 10. For example, when sealing an electronic component with a sealing material in the manufacturing process of an electronic device, it is a layer that contacts the surface of the electronic component to temporarily fix the electronic component.

[0028] The adhesive resin layer (A) contains an adhesive resin (A1). Examples of the adhesive resin (A1) include (meth)acrylic adhesive resins (a), silicone adhesive resins, urethane adhesive resins, olefin adhesive resins, styrene adhesive resins, etc. Among these, from the perspective of facilitating the adjustment of the adhesive force, etc., the (meth)acrylic adhesive resin (a) is preferred.

[0029] As the adhesive resin layer (A), a radiation crosslinkable adhesive resin layer whose adhesive force is reduced by radiation can also be used. Since the radiation crosslinkable adhesive resin layer crosslinks by irradiation with radiation and the adhesive force is significantly reduced, it becomes easy to peel the adhesive film 50 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 preferred.

[0030] Examples of the (meth)acrylic pressure-sensitive adhesive resin (a) used for the pressure-sensitive adhesive resin layer (A) include copolymers containing (meth)acrylic acid alkyl ester monomer units (a1) and monomer units (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.

[0031] The (meth)acrylic pressure-sensitive adhesive resin (a) according to the present embodiment can be obtained, for example, by copolymerizing a monomer mixture containing (meth)acrylic acid alkyl ester monomers (a1) and monomers (a2) having a functional group capable of reacting with a crosslinking agent.

[0032] 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. Preferably, they 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. can 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 the present 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 (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.

[0033] Examples of the monomer (a2) that forms the monomer (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, 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 (a) according to the present embodiment, 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 even more preferably 1% by mass or more and 10% by mass or less when the total of all monomer units in the (meth)acrylic pressure-sensitive adhesive resin (a) is 100% by mass.

[0034] The (meth)acrylic pressure-sensitive adhesive resin (a) according to the present 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 in the case of emulsion polymerization.

[0035] 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 main chain structure of propylene glycol type (e.g., manufactured by NOF Corporation; trade names: PDP-200, PDP-400, ADP-200, ADP-400), tetramethylene glycol type (e.g., manufactured by NOF Corporation; trade names: ADT-250, ADT-850), and their mixed types (e.g., manufactured by NOF Corporation; trade names: ADET-1800, ADPT-4000), etc.

[0036] In the (meth)acrylic pressure-sensitive adhesive resin (a) according to this embodiment, 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 15% by mass or less, still more preferably 0.1% by mass or more and 20% 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 (a) is 100% by mass.

[0037] Examples of the polymerizable surfactant include, for example, those obtained by introducing a polymerizable 1-propenyl group 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 obtained by introducing a polymerizable 1-propenyl group 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 type 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 15% by mass or less, still more preferably 0.1% by mass or more and 20% by mass or less, and particularly preferably 0.1% by mass or more and 5% by mass or less.

[0038] The (meth)acrylic pressure-sensitive adhesive resin (a) according to this embodiment may further contain monomer units formed from monomers having a polymerizable double bond such as vinyl acetate, acrylonitrile, and styrene, if necessary.

[0039] Examples of the polymerization reaction mechanism of the (meth)acrylic pressure-sensitive adhesive resin (a) according to this embodiment include radical polymerization, anionic polymerization, and cationic polymerization. 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, it is preferable to polymerize by radical polymerization. When polymerizing by radical polymerization, examples of radical polymerization initiators include 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, etc.; inorganic peroxides such as ammonium persulfate, potassium persulfate, sodium persulfate, etc.; and azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, 4,4'-azobis-4-cyanovaleric acid, etc.

[0040] When polymerizing by the emulsion polymerization method, among these radical polymerization initiators, inorganic peroxides such as water-soluble ammonium persulfate, potassium persulfate, sodium persulfate, etc., 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.

[0041] The 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 adhesive resin (A1). The crosslinking agent (A2) having two or more crosslinkable functional groups in one molecule is used to react with the functional groups of the 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; 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.

[0042] 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, it may be contained in excess as necessary, such as when new functional groups are generated by the crosslinking reaction or when the crosslinking reaction is slow. 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).

[0043] 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 entire pressure-sensitive adhesive resin layer (A), it is preferably 50% by mass or more and 100% by mass or less, more preferably 70% by mass or more and 100% by mass or less, still more preferably 90% by mass or more and 100% by mass or less, and particularly preferably 95% by mass or more and 100% by mass or less. Thereby, the adhesive residue on the electronic component side when peeling the pressure-sensitive adhesive film from the electronic component can be further suppressed.

[0044] 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.

[0045] The pressure-sensitive adhesive resin layer (A) can be formed, for example, by applying a pressure-sensitive adhesive on the base material layer 10. The pressure-sensitive adhesive may be dissolved in a solvent and applied as a coating solution, may be applied as an aqueous emulsion, or may be directly applied as a liquid pressure-sensitive 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 also 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 such as ethyl acetate and methyl acetate; ketone-based such as acetone and MEK; aromatic-based such as benzene, toluene, and ethylbenzene; linear or cyclic aliphatic-based such as heptane, hexane, and cyclohexane; and alcohol-based 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. As a method of applying the adhesive coating liquid, 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, a die coater method, etc. 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 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 (A) 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 (A).

[0046] <Pressure-sensitive adhesive resin layer (B)> The pressure-sensitive adhesive film 50 according to the present embodiment includes a pressure-sensitive adhesive resin layer (B) whose adhesive force decreases due to an external stimulus on the second surface 10B side opposite to the first surface 10A of the base material layer 10. Thereby, the pressure-sensitive adhesive film 50 can be easily peeled from the support substrate 80 by applying an external stimulus. Here, examples of the pressure-sensitive adhesive resin layer (B) whose adhesive force decreases due to an external stimulus include a heat-peelable pressure-sensitive adhesive resin layer whose adhesive force decreases due to heating, a radiation-peelable pressure-sensitive adhesive resin layer whose adhesive force decreases due to radiation, and the like. Among these, a heat-peelable pressure-sensitive adhesive resin layer whose adhesive force decreases due to heating is preferable. Examples of the heat-peelable pressure-sensitive adhesive resin layer include a heat-expandable adhesive containing a gas-generating component, a heat-expandable adhesive containing heat-expandable microspheres that can expand to reduce the adhesive force, and a heat-expandable adhesive in which the adhesive component undergoes a crosslinking reaction by heat to reduce the adhesive force.

[0047] In this embodiment, the heat-expandable adhesive used for the pressure-sensitive adhesive resin layer (B) is an adhesive whose adhesive force decreases or is lost when heated at a temperature exceeding, for example, 150°C. For example, a material that does not peel off at 150°C or lower and peels off at a temperature exceeding 150°C can be selected, and it is preferable that the pressure-sensitive adhesive film 50 has an adhesive force such that it does not peel off from the support substrate 80 during the manufacturing process of the electronic device. Here, the fact that the adhesive force decreases or is lost when heated at a temperature exceeding 150°C can be evaluated, for example, by attaching the pressure-sensitive 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 for 2 minutes. The specific heating temperature when heating at a temperature exceeding 150°C is set to a temperature higher than the temperature at which gas is generated or the temperature at which the thermally expandable microspheres expand, and is appropriately set according to the type of gas generated and the thermally expandable microspheres. In this embodiment, the loss of adhesive force means, for example, the case where 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.

[0048] Examples of the gas generation components used in the heat-expandable adhesive include azo compounds, azide compounds, Meldrum's acid derivatives, etc. Inorganic blowing agents such as ammonium carbonate, ammonium bicarbonate, sodium bicarbonate, ammonium nitrite, sodium borohydride, various azides, etc., 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 and other organic blowing agents can also be used. The gas generation component may be added to the pressure-sensitive resin (B1) or may be directly bonded to the pressure-sensitive resin (B1).

[0049] Examples of the thermally expandable microspheres used in the heat-expandable adhesive include microcapsules containing a blowing agent. Examples of such thermally expandable microspheres include microspheres in which a substance that easily gasifies and expands upon heating, such as isobutane, propane, pentane, etc., is encapsulated in a shell having elasticity. Examples of the material constituting the shell include vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, polysulfone, etc. The thermally expandable microspheres can be produced, for example, by the coacervation method, the interfacial polymerization method, etc. The thermally expandable microspheres can be added to the pressure-sensitive resin.

[0050] 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, and 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 temperatures exceeding 150°C.

[0051] 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.

[0052] Examples of the (meth)acrylic pressure-sensitive adhesive 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.

[0053] 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.

[0054] As the monomer (b1) that forms the (meth)acrylic acid alkyl ester monomer unit (b1), examples of the (meth)acrylic acid alkyl ester having an alkyl group with about 1 to 12 carbon atoms can be mentioned. Preferably, it is a (meth)acrylic acid alkyl ester 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. can 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, when the total of all monomer units in the (meth)acrylic pressure-sensitive adhesive resin (b) is 100% by mass, 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.

[0055] As the monomer (b2) that forms the monomer (b2) having a functional group capable of reacting with a crosslinking agent, examples of the monomer (b2) 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. Preferably, 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 (b) according to the present embodiment, 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, when the total of all monomer units in the (meth)acrylic pressure-sensitive adhesive resin (b) is 100% by mass.

[0056] The (meth)acrylic pressure-sensitive adhesive resin (b) according to the present embodiment may further contain a bifunctional monomer unit (b3) and a specific comonomer (hereinafter referred to as a polymerizable surfactant) unit having the properties of a surfactant, in addition to the monomer unit (b1) and the monomer unit (b2). The polymerizable surfactant has the property of copolymerizing with the monomer (b1), the monomer (b2), and the monomer (b3), and has the action of an emulsifier in the case of emulsion polymerization.

[0057] Examples of the monomer (b3) that forms the bifunctional monomer unit (b3) 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 names: PDP-200, PDP-400, ADP-200, ADP-400), a tetramethylene glycol type (e.g., manufactured by NOF CORPORATION; trade names: ADT-250, ADT-850), and a mixed type thereof (e.g., manufactured by NOF CORPORATION; trade names: ADET-1800, ADPT-4000).

[0058] 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 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 15% by mass or less, still more preferably 0.1% by mass or more and 20% by mass or less, and particularly preferably 0.1% by mass or more and 5% by mass or less.

[0059] 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 15% by mass or less, still more preferably 0.1% by mass or more and 20% by mass or less, and particularly preferably 0.1% by mass or more and 5% by mass or less.

[0060] The (meth)acrylic pressure-sensitive adhesive resin (b) 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.

[0061] As the polymerization reaction mechanism of the (meth)acrylic pressure-sensitive adhesive resin (b) according to this embodiment, radical polymerization, anionic polymerization, cationic polymerization, etc. can be mentioned. 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 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.

[0062] 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 are particularly preferable.

[0063] From the viewpoint of more stably performing peeling from the support substrate, the pressure-sensitive adhesive resin layer (B) according to the present embodiment preferably further contains a crosslinking agent (B2) having two or more crosslinkable functional groups in one molecule in addition to the pressure-sensitive 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 pressure-sensitive adhesive resin (B1) to adjust the adhesive force and cohesive force. Examples of such a crosslinking agent (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, and resorcin diglycidyl ether; isocyanate compounds such as tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate adduct of trimethylolpropane, polyisocyanate, diphenylmethane diisocyanate, and 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), and trimethylolpropane-tri-β-(2-methylaziridine)propionate; tetrafunctional epoxy compounds such as N,N,N',N'-tetraglycidyl-m-xylenediamine and 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.

[0064] 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 pressure-sensitive adhesive resin (B1). However, it may be contained in excess as necessary, such as when new functional groups are generated by the crosslinking reaction or when the crosslinking reaction is slow. From the viewpoint of more stably performing peeling from the support substrate, the content of the crosslinking agent (B2) in the pressure-sensitive adhesive resin layer (B) is preferably 0.5 part by mass or more and 4.0 parts by mass or less, more preferably 1.0 part by mass or more and 3.0 parts by mass or less, based on 100 parts by mass of the pressure-sensitive adhesive resin (B1).

[0065] When the total content of the pressure-sensitive adhesive resin (B1) and the crosslinking agent (B2) in the pressure-sensitive adhesive resin layer (B) is 100% by mass of the entire pressure-sensitive adhesive resin layer (B), it is preferably 50% by mass or more and 100% by mass or less, more preferably 70% by mass or more and 100% by mass or less, still more preferably 90% by mass or more and 100% by mass or less, and particularly preferably 95% by mass or more and 100% by mass or less. Thereby, the displacement of the electronic component in the sealing process can be further suppressed.

[0066] When the total content of at least one selected from the pressure-sensitive adhesive resin (B1), the crosslinking agent (B2), the gas generating component, and the thermally expandable microspheres in the pressure-sensitive adhesive resin layer (B) is 100% by mass of the entire pressure-sensitive adhesive resin layer (B), it is preferably 50% by mass or more and 100% by mass or less, more preferably 70% by mass or more and 100% by mass or less, still more preferably 90% by mass or more and 100% by mass or less, and particularly preferably 95% by mass or more and 100% by mass or less.

[0067] Further, in the adhesive film 50 according to the present embodiment, from the viewpoint of stably holding an electronic component on the adhesive resin layer (A) when the adhesive force of the adhesive resin layer (B) is reduced by applying an external stimulus and the support substrate is peeled off from the adhesive resin layer (B), the content of at least one selected from gas generating components and thermally expandable microspheres in the adhesive resin layer (A) is preferably 0.1% by mass or less, more preferably 0.05% by mass or less, still more preferably 0.01% by mass or less, when the total amount of the adhesive resin layer (A) is 100% by mass. Particularly preferably, at least one selected from gas generating components and thermally expandable microspheres is not contained in the adhesive resin layer (A).

[0068] From the viewpoint of improving the adhesion to the support substrate, the adhesive resin layer (B) according to the present embodiment preferably contains an adhesion-imparting resin in addition to the adhesive resin (B1). It is preferable to contain an adhesion-imparting resin in the adhesive resin layer (B) because it facilitates the adjustment of the adhesion to the support substrate near room temperature. As the adhesion-imparting resin, those having a softening point of 100°C or higher are preferable. Specific examples of the adhesion-imparting 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.

[0069] Among these, those having a softening point in the range of 100 to 160°C are more preferable, and those in the range of 120 to 150°C are particularly preferable. When an adhesion-imparting resin having a softening point within the above range is used, 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. Further, when a polymerized rosin ester-based adhesion-imparting resin is used as the adhesion-imparting resin, not only is there less contamination and glue residue on the support substrate, but also the adhesion to the support substrate in an environment of 80 to 130°C is improved, and after the expansion of the thermally expandable microspheres, it becomes easier to peel off from the support substrate.

[0070] 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 predetermined numerical range as desired, 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, the blending ratio of the tackifier resin is more preferably 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.

[0071] The thickness of the pressure-sensitive adhesive resin layer (B) is not particularly limited, but for example, it is preferably 5 μm or more and 300 μm or less, and more preferably 20 μm or more and 150 μm or less.

[0072] The pressure-sensitive adhesive resin layer (B) can be formed, for example, by a method of applying a pressure-sensitive adhesive coating solution on 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 the method of applying the pressure-sensitive adhesive coating solution, 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 is no particular limitation on the drying conditions of the applied pressure-sensitive adhesive, but generally, it is preferably dried in the 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 solution is completed, it may be heated at 40 to 80 °C for about 5 to 300 hours. Further, 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) the film-shaped base material layer 10 and the film-shaped pressure-sensitive adhesive resin layer (B).

[0073] <Other layers> The pressure-sensitive adhesive film 50 according to the present embodiment may further be provided, for example, with a concavo-convex absorption layer, a shock absorption layer, an easy adhesion layer, etc. 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) within a range not impairing the effects of the present embodiment.

[0074] The concavo-convex absorption layer is preferably formed of natural rubber, synthetic rubber, or synthetic resin having rubber elasticity with a Shore D hardness according to ASTM D-2240 of D type Shore of, for example, 50 or less, preferably 40 or less. The thickness of the concavo-convex absorption layer is, for example, 500 μm or less, preferably 5 to 300 μm, more preferably 10 to 150 μm.

[0075] Examples of the synthetic rubber or synthetic resin include synthetic rubbers such as nitrile-based, diene-based, and acrylic-based, thermoplastic elastomers such as polyolefin-based and polyester-based, synthetic resins having rubber elasticity such as ethylene-vinyl acetate copolymer, polyurethane, polybutadiene, and soft polyvinyl chloride. Note that even a polymer that is essentially a hard type such as polyvinyl chloride can be used in the present embodiment when it has rubber elasticity in combination with compounding agents such as plasticizers and softeners. Also, the pressure-sensitive adhesive resins exemplified in the above pressure-sensitive adhesive resin layer (A) and pressure-sensitive adhesive resin layer (B) can also be preferably used for forming the concavo-convex absorption layer.

[0076] 2. Method for manufacturing an electronic device Next, the method for manufacturing an electronic device according to the present embodiment will be described. FIGS. 2 and 3 are cross-sectional views schematically showing an example of the method for manufacturing an electronic device according to the embodiment of the present invention. The method for manufacturing an electronic device according to the present embodiment includes at least the following four steps. (1) Prepare a structure 100 including an adhesive film 50, an electronic component 70 attached to the adhesive resin layer (A) of the adhesive film 50, and a support substrate 80 attached to the adhesive resin layer (B) of the adhesive film 50. (2) Seal the electronic component 70 with a sealing material 60. (3) Apply an external stimulus to reduce the adhesive force of the adhesive resin layer (B) and peel the support substrate 80 from the structure 100. (4) Peel the adhesive film 50 from the electronic component 70. In the manufacturing method of the electronic device according to the present embodiment, the adhesive film 50 according to the present embodiment described above is used as the adhesive film for temporarily fixing the electronic component 70.

[0077] Hereinafter, each step of the manufacturing method of the electronic device according to the present embodiment will be described.

[0078] (Step (1)) First, prepare a structure 100 including an adhesive film 50, an electronic component 70 attached to the adhesive resin layer (A) of the adhesive film 50, and a support substrate 80 attached to the adhesive resin layer (B) of the adhesive film 50.

[0079] Such a structure 100 can be manufactured, for example, by the following procedure. First, on the support substrate 80, attach the adhesive film 50 so that the adhesive resin layer (B) faces the support substrate 80 side. A protective film may be attached on 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, etc. can be used.

[0080] Next, the structure 100 can be obtained by disposing the electronic component 70 on the adhesive resin layer (A) of the adhesive film 50 attached on the support substrate 80. 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.

[0081] (Step (2)) Next, the electronic component 70 is encapsulated with the encapsulant 60. The encapsulant 60 covers the electronic component 70, and the encapsulant 60 is cured at a temperature of, for example, 150°C or lower to encapsulate the electronic component 70. The form of the encapsulant 60 is not particularly limited, and examples thereof include granular, sheet-like, or liquid forms.

[0082] The encapsulant 60 is not particularly limited, and for example, an epoxy resin-based encapsulant using an epoxy resin can be used. In particular, a liquid epoxy resin-based encapsulant is preferable because the affinity of the encapsulant 60 for the adhesive film 50 is better, and the electronic component 70 can be encapsulated more evenly. Examples of such epoxy resin-based encapsulants include the T693 / R4000 series, T693 / R1000 series, T693 / R5000 series, etc. manufactured by Nagase ChemteX Corporation.

[0083] Examples of the encapsulation method include transfer molding, injection molding, compression molding, casting molding, etc. After encapsulating the electronic component 70 with the encapsulant 60, the encapsulant 60 is cured by heating at a temperature of, for example, 150°C or lower, and a structure 100 in which the electronic component 70 is encapsulated is obtained.

[0084] (Step (3)) Next, an external stimulus is applied to reduce the adhesive force of the adhesive resin layer (B) and peel the support substrate 80 from the structure 100. The support substrate 80 can be easily removed from the adhesive film 50, for example, by heating to a temperature exceeding 150°C after encapsulating the electronic component 70 to reduce the adhesive force of the adhesive resin layer (B).

[0085] (Step (4)) Next, the adhesive film 50 is removed from the electronic component 70 to obtain the electronic device 200. As a method for removing the adhesive film 50 from the electronic component 70, for example, a method of mechanically peeling it off, a method of reducing the adhesive force on the surface of the adhesive film 50 and then peeling it off, etc. can be mentioned.

[0086] (Step (5)) In the method for manufacturing an electronic device according to this embodiment, as shown in FIG. 3, a step (5) 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.

[0087] 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.

[0088] Then, bumps 320 are 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.

[0089] (Step (6)) In the method for manufacturing an electronic device according to this embodiment, as shown in FIG. 3, a step (6) of dicing the electronic device 300 to obtain a plurality of electronic devices 400 may be further provided. The dicing of the electronic device 300 can be performed by a known method.

[0090] The embodiments of the present invention have been described above, but these are examples of the present invention, and various configurations other than the above can also be adopted.

[0091] Note that the present invention is not limited to the above-described embodiments, and modifications, improvements, etc. within the scope that can achieve the object of the present invention are included in the present invention.

Example

[0092] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

[0093] Details of the materials used for producing the adhesive film are as follows.

[0094] <Adhesive resin solution SA1> Into deionized pure water, 0.5 part by mass of 4,4'-azobis-4-cyanovaleric acid (manufactured by Otsuka Chemical Co., Ltd.; trade name: ACVA) as a polymerization initiator, 78 parts by mass of n-butyl acrylate as monomer (a1), 10 parts by mass of methyl methacrylate, 9 parts by mass of 2-hydroxyethyl methacrylate as monomer (a2), and 3 parts by mass each of an ammonium salt of a sulfuric acid ester of polyoxyethylene nonylphenyl ether having a polymerizable 1-propenyl group introduced into the benzene ring (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.; trade name: Aquaron HS-1025) as a polymerizable surfactant were respectively added, and emulsion polymerization was carried out at 70 to 72 ° C for 8 hours under stirring to obtain an acrylic resin emulsion. This was neutralized with aqueous ammonia (pH = 7.0) to obtain an adhesive resin solution SA1 having a solid content concentration of 42.5%.

[0095] <Adhesive resin solution SA2> In deionized pure water, 0.5 part by mass of ammonium persulfate as a polymerization initiator, 61 parts by mass of 2-ethylhexyl acrylate as monomer (a1), 20 parts by mass of n-butyl acrylate, 9 parts by mass of methyl methacrylate, 3 parts by mass of 2-hydroxyethyl methacrylate as monomer (a2), 1 part by mass of polytetramethylene glycol diacrylate (manufactured by NOF Corporation; trade name: ADT-250) as monomer (a3), and 2 parts by mass each of an ammonium salt of sulfuric acid ester of polyoxyethylene nonyl phenyl ether with a polymerizable 1-propenyl group introduced into the benzene ring (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.; trade name: Aqualon HS-1025) as a polymerizable surfactant were respectively added, and emulsion polymerization was carried out at 70 to 72 °C for 8 hours under stirring to obtain an acrylic resin emulsion. This was neutralized with aqueous ammonia (pH = 7.0) to obtain a tacky resin solution SA2 with a solid content concentration of 56.5%.

[0096] <Adhesive Coating Liquid A1> 55 parts by mass of the tacky resin solution SA1, 45 parts by mass of the tacky resin solution SA2, 0.5 part by mass of dimethylethanolamine, and 4 parts by mass of an epoxy-based compound (manufactured by Nagase ChemteX Corporation, Ex-1610) as a crosslinking agent were respectively mixed to obtain an adhesive coating liquid A1.

[0097] <Tacky Resin Solution SB1> In a mixed solvent containing ethyl acetate and toluene, 0.5 part by mass of t-butyl peroxy-2-ethylhexanoate (manufactured by NOF Corporation; trade name: Perbutyl O (registered trademark)) as a polymerization initiator, 35 parts by weight of 2-ethylhexyl acrylate as monomer (b1), 40 parts by mass of n-butyl acrylate, 15 parts by mass of ethyl acrylate, and 10 parts by mass of 2-hydroxyethyl methacrylate as monomer (b2) were respectively added, and solution polymerization was carried out at 83 to 87 °C for 11 hours under stirring to obtain an acrylic resin solution with a solid content concentration of 45% by mass. This was used as the tacky resin solution SB1.

[0098] <Adhesive Coating Liquid B1> 100 parts by mass of the pressure-sensitive adhesive resin solution SB1 and 0.9 parts by mass of an isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals, Inc.; trade name: Orestar P49-75S) (2 parts by mass based on 100 parts by mass of the pressure-sensitive adhesive resin) were each mixed, and the solid content concentration was adjusted to 40% with ethyl acetate to obtain a pressure-sensitive adhesive coating solution B1.

[0099] <Pressure-sensitive adhesive coating solution B2> 100 parts by mass of the pressure-sensitive adhesive resin solution SB1, 2.25 parts by weight of a polymerized rosin ester-based tackifier (manufactured by Arakawa Chemical Industries, Ltd.; trade name: Pencil D-125) (5 parts by mass based on 100 parts by mass of the pressure-sensitive adhesive resin), 1.2 parts by mass of an isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals, Inc.; trade name: Orestar P49-75S) (2 parts by mass based on 100 parts by mass of the pressure-sensitive adhesive resin), and 6.75 parts by mass of thermally expandable microspheres (manufactured by Sekisui Chemical Co., Ltd.; trade name: Advance EM-503) (15 parts by mass based on 100 parts by mass of the pressure-sensitive adhesive resin) were each mixed, and the solid content concentration was adjusted to 30% with ethyl acetate to prepare a pressure-sensitive adhesive coating solution B2.

[0100] <Pressure-sensitive adhesive resin solution SB2> Into a mixed solvent containing ethyl acetate and toluene, 0.25 parts by mass of t-butyl peroxy-2-ethylhexanoate (manufactured by NOF Corporation; trade name: Perbutyl O (registered trademark)) as a polymerization initiator, 72 parts by mass of n-butyl acrylate as monomer (b1), 18 parts by mass of methyl methacrylate, 7 parts by mass of 2-hydroxyethyl methacrylate as monomer (b2), and 3 parts by mass of acrylic acid were each added, and solution polymerization was carried out at 83 to 87 °C for 11 hours under stirring to obtain an acrylic resin solution with a solid content concentration of 45% by mass. This was used as the pressure-sensitive adhesive resin solution SB2.

[0101] <Pressure-sensitive adhesive coating solution B3> 100 parts by mass of the pressure-sensitive adhesive resin solution SB2, 0.05 parts by mass of dimethylethanolamine, and 1.35 parts by mass of an epoxy-based crosslinking agent (manufactured by Nagase ChemteX Corporation, Ex-614) (3 parts by mass based on 100 parts by mass of the pressure-sensitive adhesive resin) were each mixed, and the solid content concentration was adjusted to 40% with ethyl acetate to obtain a pressure-sensitive adhesive coating solution B3.

[0102] <Adhesive Coating Liquid B4> 100 parts by mass of the pressure-sensitive adhesive resin solution SB2, 2.25 parts by weight of a polymerized rosin ester-based tackifier (manufactured by Arakawa Chemical Industries, Ltd.; trade name: Pencil D-125) (5 parts by mass with respect to 100 parts by mass of the pressure-sensitive adhesive resin), 1.2 parts by mass of an epoxy-based crosslinking agent (manufactured by Nagase ChemteX Corporation, Ex-1610) (2 parts by mass with respect to 100 parts by mass of the pressure-sensitive adhesive resin), and 9 parts by mass of thermally expandable microspheres (manufactured by Sekisui Chemical Co., Ltd.; trade name: Advance EM-503) (20 parts by mass with respect to 100 parts by mass of the pressure-sensitive adhesive resin) were each mixed, and the solid content concentration was adjusted to 30% with ethyl acetate to prepare the adhesive coating liquid B4.

[0103] <Pressure-Sensitive Adhesive Resin Coating Liquid B5> 100 parts by mass of the pressure-sensitive adhesive resin solution SB2 and 1 part by mass of an ester-based crosslinking agent (manufactured by Mitsubishi Gas Chemical Company, solid content concentration 100%, Tetrad-C) were each mixed, and the solid content concentration was adjusted to 30% with ethyl acetate to obtain the adhesive coating liquid B5.

[0104] <Pressure-Sensitive Adhesive Resin Coating Liquid B6> 100 parts by mass of the pressure-sensitive adhesive resin solution SB2, 2.25 parts by weight of a polymerized rosin ester-based tackifier (manufactured by Arakawa Chemical Industries, Ltd.; trade name: Pencil D-125) (5 parts by mass with respect to 100 parts by mass of the pressure-sensitive adhesive resin), 1.2 parts by mass of an epoxy-based crosslinking agent (manufactured by Mitsubishi Gas Chemical Company, solid content concentration 100%, Tetrad-C) (2 parts by mass with respect to 100 parts by mass of the pressure-sensitive adhesive resin), and 9 parts by mass of thermally expandable microspheres (manufactured by Sekisui Chemical Co., Ltd.; trade name: Advance EM-503) (20 parts by mass with respect to 100 parts by mass of the pressure-sensitive adhesive resin) were each mixed, and the solid content concentration was adjusted to 30% with ethyl acetate to prepare the adhesive coating liquid B6.

[0105] [Example 1] After applying the adhesive coating solution A1 onto a polyethylene terephthalate (PET) film (thickness: 38 μm) as the base material layer and drying it, an adhesive resin layer (A) with a thickness of 10 μm was formed. Next, the adhesive coating solution B1 was applied onto the surface of the PET film opposite to the adhesive resin layer (A) through a separator and dried to form a concavo-convex absorbing layer with a thickness of 20 μm. Then, an adhesive resin layer (B) with a thickness of 25 μm formed from the adhesive coating solution B2 was provided thereon, and an adhesive film having the adhesive resin layer (B) was obtained. The adhesive resin layer (B) was formed by a method of forming it on a separate separator and transferring it onto the concavo-convex absorbing layer. The following evaluations were performed on the obtained adhesive film. The obtained results are shown in Table 1.

[0106] [Example 2] An adhesive film was obtained in the same manner as in Example 1, except that the adhesive coating solution B3 was used instead of the adhesive coating solution B1 and the adhesive coating solution B4 was used instead of the adhesive coating solution B2. The following evaluations were performed on the obtained adhesive film. The obtained results are shown in Table 1.

[0107] [Comparative Example 1] An adhesive film was obtained in the same manner as in Example 1, except that the adhesive resin solution B5 was used instead of the adhesive coating solution B1 and the adhesive coating solution B6 was used instead of the adhesive coating solution B2. The following evaluations were performed on the obtained adhesive film. The obtained results are shown in Table 1.

[0108] [Evaluation] (1) Measurement of the integrated value F of tack force 2.5 and F 30 of Using the tacking tester TAC-II manufactured by RHESCA, a probe was pressed onto the adhesive resin layer (B) of the pressure-sensitive adhesive film obtained in the examples and comparative examples for 60 seconds under the conditions of a probe load of 100 gf and a probe pushing speed of 120 mm / min. Subsequently, the tack strength (gf) was measured at a test temperature of 130 °C and test speeds of 2.5 mm / min and 30 mm / min, respectively. Here, the measurement time was taken on the horizontal axis and the tack strength (gf) on the vertical axis, and the integral value from the point where the tack strength began to increase from 0 to the point where it became 0 again was calculated for each, and the obtained values were designated as F 2.5 [gf ·s and F 30 [gf ·s , respectively.

[0109] (2) Displacement of electronic components in the encapsulation process The adhesive resin layer (B) side of the pressure-sensitive adhesive film obtained in the examples and comparative examples was adhered onto a stainless steel plate (φ310 mm, thickness 1.5 mm) for compression molding, and as an electronic component, a 5.0 mm square semiconductor chip was placed and adhered onto the adhesive resin layer (A) of the pressure-sensitive adhesive film in a grid pattern with a 2.0 mm interval to obtain a structure. Subsequently, using a compression molding machine, a plurality of semiconductor chips on the adhesive resin layer (A) were encapsulated by compression molding with a liquid epoxy resin-based encapsulant (manufactured by Nagase ChemteX Corporation, product name: T693 / R4212-2C) to obtain a structure in which an encapsulation resin wafer (φ300 mm, thickness 0.5 mm) was formed on the stainless steel plate. Subsequently, the displacement of the electronic components was evaluated according to the following criteria. None: No displacement of the semiconductor chip was observed visually Yes: Displacement was observed visually in at least a part of the semiconductor chip

[0110] (3) Heat peelability after the encapsulation process In the examples and comparative examples, the adhesive resin layer (B) side of a 10 cm × 10 cm adhesive film was pressure-bonded onto a mirror-finished stainless steel plate (SUS304BA plate) with a size of 10 cm in length × 10 cm in width × 1 mm in thickness under a pressure of 0.5 MPa. Subsequently, the obtained structure was heat-treated at 140 °C for 60 minutes to stabilize the adhesive forces of the adhesive resin layer (A) and the adhesive resin layer (B). Then, the structure was cooled to room temperature. Subsequently, on a hot plate, after heating the structure at 190 °C for 2 minutes, the adhesive film was peeled off from the stainless steel plate under the conditions of 23 °C and a tensile speed of 300 mm / min, and the 180° peel strength was measured. The possibility of heat peeling of the adhesive film from the stainless steel plate was evaluated according to the following criteria. Acceptable: The 180° peel strength is less than 0.5 N / 25 mm Not acceptable: The 180° peel strength is 0.5 N / 25 mm or more

[0111] [Table 1]

[0112] The integrated value of the tack force (F 2.5 ) is 1.0 gf ·s or more, and the integrated value of the tack force (F 30 ) is 7.0 gf ·s or more. In the examples using the adhesive film, no displacement of the semiconductor element was observed in the sealing process. Therefore, it can be understood that the adhesive film of the examples can suppress the displacement of the electronic component in the sealing process. In contrast, the integrated value of the tack force (F 2.5 ) is less than 1.0 gf ·s , and the integrated value of the tack force (F 30 ) is less than 7.0 gf ·s . In the comparative examples using the adhesive film, displacement of the semiconductor element was observed in the sealing process. Therefore, it can be understood that displacement of the electronic component occurs in the sealing process with the adhesive film of the comparative examples.

[0113] This application claims the priority based on Japanese Patent Application No. 2018-061342 filed on March 28, 2018, and incorporates all of its disclosure herein.

Claims

1. A base material layer, An adhesive resin layer (A) provided on the first surface side of the base material layer and serving as a layer for temporarily fixing an electronic component when the electronic component is sealed with a sealing material in the manufacturing process of an electronic device. 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 comprising: The adhesive resin layer (B) is a layer that is attached to a support substrate in the manufacturing process of an electronic device. The adhesive resin layer (B) is composed of a heat-expandable adhesive containing thermally expandable microspheres that can expand to reduce the adhesive force. The adhesive resin layer (B) contains an adhesive resin (B1) and a crosslinking agent (B2). The crosslinking agent (B2) is contained in an amount of 0.5 parts by mass or more and 4.0 parts by mass or less with respect to 100 parts by mass of the adhesive resin (B1). The adhesive resin (B1) contains 10% by mass or more and 98.9% by mass or less of a (meth)acrylic acid alkyl ester monomer unit (b1) and 1% by mass or more and 40% by mass or less of a monomer unit (b2) having a functional group capable of reacting with the crosslinking agent (B2) with respect to a total of 100% by mass of all monomer units. The crosslinking agent (B2) is at least one selected from an epoxy-based compound, an isocyanate-based compound, an aziridine-based compound, and a melamine-based compound. The integrated value (F ２．５ ) of the tack force of the adhesive resin layer (B) measured by the following Method 1 at a test speed of 2.5 mm / min and a test temperature of 130°C is 1.0 gf·s or more and 7.5 gf·s or less, and the integrated value (F ３０ ) of the tack force of the adhesive resin layer (B) at a test speed of 30 mm / min and a test temperature of 130°C is 7.0 gf·s or more and 25.0 gf·s or less. An adhesive film. (Method 1) Using a tack tester, after pressing the probe onto the adhesive resin layer (B) for 60 seconds under the conditions of a probe load of 100 gf and a probe pressing speed of 120 mm / min, the tack strength (gf) was measured at a test temperature of 130°C, test speeds of 2.5 mm / min and 30 mm / min, respectively. With the measurement time on the horizontal axis and the tack strength (gf) on the vertical axis, the integral value from the point where the tack strength began to rise from 0 to the point where it returned to 0 was calculated respectively, and each of the F ２．５ and the F ３０ is defined as such.

2. In the adhesive film according to claim 1, The monomer (b1) that forms the (meth)acrylic acid alkyl ester monomer unit (b1) is a (meth)acrylic acid alkyl ester having an alkyl group with 1 to 12 carbon atoms.

3. In the adhesive film according to claim 1 or 2, The monomer (b2) that forms the monomer unit (b2) having a functional group capable of reacting with the crosslinking agent (B2) is at least one selected from 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, and tertiary-butylaminoethyl methacrylate.

4. In the adhesive film according to any one of claims 1 to 3, 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.

5. In the adhesive film according to any one of claims 1 to 4, The pressure-sensitive adhesive resin layer (B) is a pressure-sensitive adhesive film whose adhesive force decreases when heated at a temperature exceeding 150°C.

6. In the pressure-sensitive adhesive film according to any one of Claims 1 to 5, when the content of at least one selected from gas-generating components and thermally expandable microspheres in the pressure-sensitive adhesive resin layer (A) is 0.1% by mass or less based on 100% by mass of the entire pressure-sensitive adhesive resin layer (A), it is a pressure-sensitive adhesive film.

7. In the pressure-sensitive adhesive film according to any one of Claims 1 to 6, the pressure-sensitive adhesive resin layer (A) is a pressure-sensitive adhesive film containing a (meth)acrylic pressure-sensitive adhesive resin.

8. A step (1) of preparing a structure including the pressure-sensitive adhesive film according to any one of Claims 1 to 7, an electronic component attached to the pressure-sensitive adhesive resin layer (A) of the pressure-sensitive adhesive film, and a support substrate attached to the pressure-sensitive adhesive resin layer (B) of the pressure-sensitive adhesive film; A step (2) of sealing the electronic component with a sealing material; A step (3) of reducing the adhesive force of the pressure-sensitive adhesive resin layer (B) by applying an external stimulus and peeling the support substrate from the structure; A step (4) of peeling the pressure-sensitive adhesive film from the electronic component; A method for manufacturing an electronic device including at least these steps.

9. In the method for manufacturing an electronic device according to Claim 8, a method for manufacturing an electronic device, wherein the sealing material is an epoxy resin-based sealing material.

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