Electronic device production method

Abstract

An electronic device production method including: a step for preparing a structure provided with a support substrate (60) and an adhesive film (50) that is attached to the support substrate (60); a step for forming a resist pattern (70) on the adhesive film (50) using a resist; a step for forming a wiring layer (80) on the adhesive film (50) by electroless plating; and a step for removing the resist pattern (70).

Description

Manufacturing method of electronic device

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

[0002] 2. Description of the Related Art Fan-out type WLP (wafer level package) has been developed as a technology that can reduce the size and weight of electronic devices (for example, semiconductor devices).

[0003] As a technique relating to a manufacturing method of such a fan-out type WLP, for example, the technique described in Patent Document 1 can be given.

[0004] Patent Document 1 describes a heat-resistant adhesive sheet for semiconductor device manufacturing that is used by adhering when resin-encapsulating a substrateless semiconductor chip, the heat-resistant adhesive sheet having a base layer and an adhesive layer, the adhesive layer having an adhesive strength to SUS304 after lamination of 0.5 N / 20 mm or more and hardening due to stimuli received up to the completion of the resin-encapsulation process to reduce the package peel strength to 2.0 N / 20 mm or less. Patent Document 1 also describes that when resin-encapsulating a substrateless semiconductor chip that does not use a metal lead frame, the chip is held in place without shifting from the specified position and no adhesive residue is left after use. Furthermore, no gas is generated when heated, and the adhesive does not weld, allowing wiring to be reliably provided, thereby improving the manufacturing yield of semiconductor packages and reducing contamination due to adhesive residue when the sheet is peeled off.

[0005] JP 2011-134811 A

[0006] There are two main methods for fabricating fan-out WLP, called eWLB (Embedded Wafer Level Ball Grid Array). The first method is called the chip-first process, in which multiple electronic components such as semiconductor chips are temporarily fixed in a spaced-apart state on an adhesive film attached to a support substrate, resin sealing is performed, and a redistribution layer (RDL layer) is formed on top of that. The second method is called the RDL-first process, in which a redistribution layer (RDL layer) is formed on a temporary fixing material, electronic components such as semiconductor chips are connected, and then resin sealing is performed.

[0007] The RDL first process can be broadly divided into three types of methods for forming the wiring layer: subtractive, semi-additive, and full-additive. In the subtractive method, a metal layer is formed on a temporary fixing material and then etched to form the wiring layer. In the semi-additive method, (1) a thin metal film serving as a seed layer is formed on the temporary fixing material, (2) a resist pattern is formed on the thin metal film using photolithography or other methods, (3) electroplating is performed on the metal film to form a wiring layer according to the resist pattern, (4) the resist pattern is removed, and (5) etching is performed to dissolve the plating seed layer in the areas covered by the resist pattern to form the wiring layer. In the full-additive method, the surface on which the wiring layer is to be formed is first catalyzed, a resist pattern is then formed on the catalyzed surface using photolithography or other methods, and the wiring layer is then formed by electroless plating.

[0008] The full additive method is advantageous for forming a fine wiring layer because it allows the wiring layer to be formed without etching.

[0009] The present invention has been made in view of the above circumstances, and provides a method for manufacturing an electronic device that is capable of forming a fine wiring layer on an adhesive film.

[0010] According to the present invention, there is provided a method for manufacturing an electronic device as follows.

[0011] [1] A method for manufacturing an electronic device, comprising the steps of: preparing a structure including a support substrate and an adhesive film attached to the support substrate; forming a resist pattern on the adhesive film using a resist; forming a wiring layer on the adhesive film by electroless plating; and removing the resist pattern. [2] A method for manufacturing an electronic device according to [1] above, wherein the wiring layer is formed without an etching step. [3] A method for manufacturing an electronic device according to [1] or [2] above, further comprising the step of mounting electronic components on the wiring layer. [4] A method for manufacturing an electronic device according to [3] above, further comprising the step of encapsulating the electronic components mounted on the wiring layer with an encapsulant. [5] A method for manufacturing an electronic device according to [4] above, wherein the adhesive resin layer (B) includes a layer whose adhesive strength is reduced by an external stimulus, and further comprising, after the encapsulation step, a first peeling step of applying an external stimulus to reduce the adhesive strength of the adhesive resin layer (B) and peeling the adhesive film from the support substrate or the wiring layer. [6] The method for manufacturing an electronic device according to [5] above, further comprising a second peeling step of peeling the adhesive film from the support substrate or the wiring layer after the first peeling step. [7] The method for manufacturing an electronic device according to any of [1] to [6] above, wherein the electronic device includes a fan-out package. [8] The method for manufacturing an electronic device according to any of [1] to [7] above, wherein the adhesive film comprises a base layer, an adhesive resin layer (A) provided on a first surface of the base layer, and an adhesive resin layer (B) provided on a second surface of the base layer, at least one of the adhesive resin layer (A) or the adhesive resin layer (B) containing a reducing agent, and the wiring layer is formed on the surface of the adhesive resin layer (A) or the adhesive resin layer (B) on which the layer containing the reducing agent is provided. [9] The method for manufacturing an electronic device according to [8] above, wherein the reducing agent contains one or more metals selected from the group consisting of iron, cobalt, nickel, tin, copper, silver, palladium, iridium, platinum, and gold.

[10] The method for producing an electronic device according to [9] above, wherein the reducing agent contains palladium.

[11] The method for producing an electronic device according to

[10] above, wherein the reducing agent comprises one or more selected from the group consisting of elemental palladium and palladium halides.

[12] The method for producing an electronic device according to any one of [8] to

[11] above, wherein at least one of the adhesive resin layer (A) and the adhesive resin layer (B) comprises one or more selected from the group consisting of a (meth)acrylic adhesive resin, a silicone adhesive resin, a urethane adhesive resin, an olefin adhesive resin, and a styrene adhesive resin.

[13] The method for producing an electronic device according to any one of [8] to

[12] above, wherein the adhesive resin layer (B) comprises a self-peeling adhesive resin layer whose adhesive strength is reduced by an external stimulus.

[14] The method for producing an electronic device according to

[13] above, wherein the self-peeling adhesive resin layer comprises a thermally expandable adhesive agent, and the thermally expandable adhesive agent is an adhesive whose adhesive strength is reduced or lost when heated at a temperature exceeding 150°C.

[0012] According to the present invention, it is possible to provide a method for manufacturing an electronic device that is capable of forming a fine wiring layer on an adhesive film.

[0013] 1 is a cross-sectional view schematically showing an example of the structure of an adhesive film according to the present invention, and FIG. 2 is a cross-sectional view schematically showing an example of forming a wiring layer by electroless plating on an adhesive film according to the present invention.

[0014] <Method for Manufacturing Electronic Device> First, a method for manufacturing an electronic device according to this embodiment will be described.

[0015] The method for manufacturing an electronic device according to this embodiment includes the steps of preparing a structure comprising a support substrate and an adhesive film attached to the support substrate, forming a resist pattern on the adhesive film using a resist, forming a wiring layer on the adhesive film by electroless plating, and removing the resist pattern.

[0016] Electroless plating is a method of reducing and depositing metal ions through a chemical reaction between metal ions and a reducing agent.

[0017] Here, the formation of a wiring layer by electroless plating on an adhesive film according to this embodiment will be described with reference to FIG. 2 , taking as an example a case in which the adhesive resin layer (A) contains a reducing agent. (1) The second surface of the adhesive film 50 (the surface facing the second surface 10B of the base layer 10) is attached to a support substrate 60 to prepare a structure 100. (2) A resist pattern 70 is formed on the first surface of the adhesive film 50 (the surface facing the first surface 10A of the base layer 10) using a resist. (3) A wiring layer 80 is formed on the first surface of the adhesive film 50 by electroless plating. Specifically, a plating solution is brought into contact with areas of the first surface of the adhesive film 50 where the resist pattern 70 is not formed, and the plating solution is brought into contact with the first surface of the adhesive film 50, thereby reducing and precipitating metal ions in the plating solution, thereby forming the wiring layer 80. (4) The resist pattern 70 is removed.

[0018] Although the above description deals with the case where the adhesive resin layer (A) contains a reducing agent, the adhesive resin layer (B) may also contain a reducing agent. In this case, the first surface of the adhesive film 50 is attached to the support substrate 60, and the resist pattern 70 and wiring layer 80 are formed on the second surface. The adhesive resin layer (A) and the adhesive resin layer (B) may not contain a reducing agent. In this case, for example, electroless plating can be performed by attaching a reducing agent to the first or second surface of the adhesive film 50 and then immersing the adhesive film 50 in a plating solution. Alternatively, electroless plating may be performed by immersing the adhesive film 50 in a plating solution and then attaching a reducing agent to the adhesive film 50.

[0019] According to the method for manufacturing an electronic device according to this embodiment, electroless plating can be performed on the adhesive film 50, and therefore the wiring layer 80 can be formed by a full additive method that does not require etching.

[0020] In the method for manufacturing an electronic device according to this embodiment, it is preferable that the wiring layer 80 is formed without an etching process. By not performing etching, it is possible to avoid breaks or shorts in the wiring due to etching, which is advantageous from the viewpoint of forming fine wiring. Furthermore, being able to form the wiring layer 80 without etching is also advantageous from the viewpoint of reducing the amount of waste liquid and reducing the environmental load. Therefore, the adhesive film 50 according to this embodiment can reduce the amount of waste liquid and reduce the environmental load.

[0021] The electroless plating method in the method for manufacturing an electronic device according to this embodiment is not particularly limited. For example, after forming the resist pattern 70, electroless plating can be performed by immersing the resist pattern 70 in a plating solution to form a plating bath.

[0022] The plating solution according to the present embodiment is not particularly limited as long as it contains a metal element, such as one or more metal elements selected from the group consisting of copper, platinum, gold, silver, nickel, chromium, cobalt, and tin, preferably one or more metal elements selected from the group consisting of copper and nickel, and more preferably nickel.

[0023] The plating solution according to this embodiment contains one or more selected from the group consisting of water and water-soluble organic solvents.

[0024] The treatment temperature for electroless plating is not particularly limited and is, for example, 25° C. or higher, preferably 35° C. or higher, more preferably 45° C. or higher, and is, for example, 95° C. or lower. The treatment time for electroless plating is also not particularly limited and is, for example, 5 minutes or higher, preferably 10 minutes or higher, more preferably 20 minutes or higher, and is, for example, 3 hours or lower.

[0025] The method for manufacturing an electronic device according to this embodiment may further include a step of mounting electronic components on the wiring layer 80 .

[0026] The method for manufacturing an electronic device according to this embodiment may further include a step of sealing the electronic components mounted on the wiring layer 80 with a sealing material.

[0027] The method for sealing the electronic components with the sealing material is not particularly limited, but for example, the electronic components can be sealed by heating and curing the sealing material. The heating temperature is not particularly limited, but is preferably 150°C or less from the viewpoint of maintaining the adhesive strength of the adhesive resin layer (B).

[0028] The form of the sealing material according to this embodiment is not particularly limited, but may be, for example, granular, sheet, or liquid.

[0029] The components of the sealing material are not particularly limited, but preferably include an epoxy resin sealing material, and more preferably include a liquid epoxy resin sealing material, from the viewpoint of improving the affinity of the sealing material to the pressure-sensitive adhesive film 50 and enabling more uniform sealing of the electronic components. Examples of such epoxy resin sealing materials that can be used include the T693 / R4000 series, T693 / R1000 series, and T693 / R5000 series manufactured by Nagase ChemteX Corporation.

[0030] The sealing method in the sealing step is not particularly limited, but it is preferable to seal the electronic component with the sealing material using one or more molding methods selected from the group consisting of transfer molding, injection molding, compression molding, and cast molding.

[0031] The method for manufacturing an electronic device according to this embodiment may further include a first peeling step in which the adhesive resin layer (B) includes a layer whose adhesive strength is reduced by an external stimulus, and after the sealing step, the adhesive film 50 is peeled off from the support substrate 60 or the wiring layer 80 by applying an external stimulus to reduce the adhesive strength of the adhesive resin layer (B). The means for reducing the adhesive strength of the adhesive resin layer (B) is not particularly limited, but for example, when the adhesive resin layer (B) includes a layer whose adhesive strength is reduced by heating to a temperature exceeding 150°C, the adhesive strength can be reduced by heating to a temperature exceeding 150°C.

[0032] The method for manufacturing an electronic device according to this embodiment may further include, after the first peeling step, a second peeling step of peeling the adhesive film 50 from the support substrate 60 or the wiring layer 80. Examples of methods for peeling the adhesive film 50 from the support substrate 60 or the wiring layer 80 include a mechanical peeling method and a method of reducing the adhesive strength of the surface of the adhesive film 50 before peeling.

[0033] The type of electronic device obtained by the method for manufacturing an electronic device according to this embodiment is not particularly limited, but preferably includes a fan-out type package. In a fan-out type package, terminals can be spread to the outside of the chip (fan out), so it can be used in applications where the number of terminals is large compared to the chip area. In addition, since a package substrate is not required, it can also be made thinner.

[0034] In the method for manufacturing an electronic device according to this embodiment, preferably, the adhesive film 50 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 at least one of the adhesive resin layer (A) or the adhesive resin layer (B) contains a reducing agent, and a wiring layer 80 is formed on the surface of the adhesive resin layer (A) or the adhesive resin layer (B) on which the layer containing the reducing agent is provided.

[0035] The reducing agent according to the present embodiment is not particularly limited as long as it can reduce and deposit metal ions in the plating solution. From the viewpoint of more efficiently reducing and depositing metal ions, the reducing agent preferably contains one or more elements selected from the group consisting of iron, cobalt, nickel, tin, copper, silver, palladium, iridium, platinum, and gold, more preferably contains one or more elements selected from the group consisting of copper, silver, palladium, iridium, platinum, and gold, even more preferably contains palladium, and even more preferably contains one or more elements selected from the group consisting of elemental palladium and palladium halides such as palladium chloride and palladium bromide.

[0036] The shape of the reducing agent according to this embodiment is not particularly limited, but from the viewpoint of more efficiently reducing and depositing metal ions, it is preferably in the form of particles.

[0037] Examples of commercially available reducing agents according to this embodiment include palladium nanopowder such as "ML-001N" manufactured by Iox Corporation, and composite particles of palladium particles and resin particles such as "HYPERTECH (registered trademark) PL-series photosensitive electroless plating nucleating agent" manufactured by Nissan Chemical Industries, Ltd.

[0038] The content of the reducing agent in this embodiment is not particularly limited as long as it is an amount that can reduce and precipitate metal ions in the plating solution, but from the viewpoint of more efficiently reducing and precipitating metal ions, it is preferably 0.01 mass% or more, more preferably 0.05 mass% or more, even more preferably 0.1 mass% or more, even more preferably 0.5 mass% or more, even more preferably 1.0 mass% or more, and even more preferably 5.0 mass% or more, relative to the entire adhesive film 50.

[0039] The method for incorporating the reducing agent according to this embodiment into at least one of the adhesive resin layer (A) and the adhesive resin layer (B) is not particularly limited, and an adhesive containing the reducing agent may be applied to the base layer 10, or an adhesive resin layer may be formed on the base layer 10 in advance and then impregnated with the reducing agent.

[0040] <Adhesive Film 50 Used in Method for Manufacturing Electronic Device> Next, the adhesive film 50 used in the method for manufacturing an electronic device according to this embodiment will be described.

[0041] First, each layer constituting the adhesive film 50 according to this embodiment will be described.

[0042] (Substrate Layer 10) The substrate layer 10 is a layer provided for the purpose of improving the handleability, mechanical properties, heat resistance, and other properties of the pressure-sensitive adhesive film 50. The substrate layer 10 is not particularly limited, but examples thereof include a resin film. A known thermoplastic resin can be used as the resin constituting the resin film. Examples include one or more selected from 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 polymethaxylene adipamide; polyacrylate; polymethacrylate; polyvinyl chloride; polyvinylidene chloride; polyimide; polyetherimide; ethylene-vinyl acetate copolymer; polyacrylonitrile; polycarbonate; polystyrene; ionomer; polysulfone; polyethersulfone; and polyphenylene ether. Among these, from the viewpoint of an excellent balance of transparency, mechanical strength, price, and the like, one or more selected from polypropylene, polyethylene terephthalate, polyethylene naphthalate, polyamide, and polyimide are preferred, and at least one selected from polyethylene terephthalate and polyethylene naphthalate is more preferred.

[0043] The base layer 10 may be a single layer or two or more layers. The resin film used to form the base layer 10 may be a stretched film or a uniaxially or biaxially stretched film, but from the viewpoint of improving the mechanical strength of the base layer 10, a uniaxially or biaxially stretched film is preferred.

[0044] From the viewpoint of obtaining good film properties, the thickness of the substrate 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 substrate layer 10 may be subjected to a surface treatment to improve adhesion to other layers. Specifically, corona treatment, plasma treatment, undercoat treatment, primer coating treatment, etc. may be performed.

[0045] (Adhesive resin layer (A)) The adhesive resin layer (A) is a layer provided on one side of the base layer 10, and is a layer that comes into contact with the surface of an electronic component to temporarily fix the electronic component when sealing the electronic component with a sealing material in the manufacturing process of an electronic device, for example.

[0046] The adhesive resin layer (A) preferably contains one or more selected from a (meth)acrylic adhesive resin, a silicone adhesive resin, a urethane adhesive resin, an olefin adhesive resin, and a styrene adhesive resin, and among these, more preferably contains a (meth)acrylic adhesive resin (a) from the viewpoint of facilitating adjustment of adhesive strength.

[0047] The (meth)acrylic adhesive resin (a) used in the adhesive resin layer (A) may be, for example, 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 this embodiment, the (meth)acrylic acid alkyl ester refers to an acrylic acid alkyl ester, a methacrylic acid alkyl ester, or a mixture thereof.

[0048] The (meth)acrylic adhesive resin (a) according to this 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.

[0049] Examples of the monomer (a1) forming the (meth)acrylic acid alkyl ester monomer unit (a1) include (meth)acrylic acid alkyl esters having an alkyl group containing about 1 to 12 carbon atoms. (Meth)acrylic acid alkyl esters having an alkyl group containing 1 to 8 carbon atoms are preferred. Specific examples include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, and 2-ethylhexyl methacrylate. These may be used alone or in combination of two or more. In the (meth)acrylic 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 adhesive resin (a) is taken as 100% by mass.

[0050] Examples of the monomer (a2) that forms the monomer (a2) having a functional group reactive 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, tert-butylaminoethyl acrylate, and tert-butylaminoethyl methacrylate. Preferred are acrylic acid, methacrylic acid, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide, methacrylamide, and the like. These may be used alone or in combination of two or more. In the (meth)acrylic 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 adhesive resin (a) is 100% by mass.

[0051] The (meth)acrylic adhesive resin (a) according to this embodiment may further contain, in addition to the monomer unit (a1) and the monomer unit (a2), a bifunctional monomer unit (a3) ​​or a specific comonomer unit having surfactant properties (hereinafter referred to as a polymerizable surfactant). The polymerizable surfactant has the property of copolymerizing with the monomer (a1), the monomer (a2), and the monomer (a3), and also acts as an emulsifier when emulsion polymerization is performed.

[0052] Examples of the monomer (a3) ​​forming 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, diacrylates or acrylates having both ends thereof. or dimethacrylates whose main chain structure is a propylene glycol type (for example, NOF Corporation, trade names: PDP-200, PDP-400, ADP-200, ADP-400), a tetramethylene glycol type (for example, NOF Corporation, trade names: ADT-250, ADT-850), or a mixture thereof (for example, NOF Corporation, trade names: ADET-1800, ADPT-4000).

[0053] In the (meth)acrylic adhesive resin (a) according to the present 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, even 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 adhesive resin (a) is 100% by mass.

[0054] Examples of the polymerizable surfactant include those in which a polymerizable 1-propenyl group has been introduced into the benzene ring of polyoxyethylene nonylphenyl ether (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.; trade names: AQUALON RN-10, RN-20, RN-30, RN-50, etc.), those in which a polymerizable 1-propenyl group has been introduced into the benzene ring of an ammonium salt of a sulfate ester of polyoxyethylene nonylphenyl ether (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.; trade names: AQUALON HS-10, HS-20, HS-1025, etc.), and sulfosuccinic acid diesters having a polymerizable double bond in the molecule (manufactured by Kao Corporation; trade names: Latemul S-120A, S-180A, etc.). In the (meth)acrylic adhesive resin (a) according to the present embodiment, 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, even 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 sum of all monomer units in the (meth)acrylic adhesive resin (a) is 100% by mass.

[0055] The (meth)acrylic adhesive resin (a) according to the present embodiment may further contain, if necessary, a monomer unit formed from a monomer having a polymerizable double bond, such as vinyl acetate, acrylonitrile, or styrene.

[0056] The polymerization reaction mechanism of the (meth)acrylic adhesive resin (a) according to this embodiment may be radical polymerization, anionic polymerization, cationic polymerization, or the like. Taking into consideration the production cost of the (meth)acrylic adhesive resin (a), the influence of the functional groups of the monomer, and the influence of ions on the surface of electronic components, polymerization by radical polymerization is preferred. When polymerization is carried out by radical polymerization, the radical polymerization initiator may be selected from the group consisting of 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-butylperoxy-2-hexanoate, t-butyl peroxy, and the like. Examples of the peroxide include organic peroxides such as 2-ethylhexanoate, t-butylperoxy-3,5,5-trimethylhexanoate, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, t-butyl peroxide, and di-t-amyl peroxide; inorganic peroxides such as ammonium persulfate, potassium persulfate, and sodium persulfate; and azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, and 4,4'-azobis-4-cyanovaleric acid.

[0057] When polymerization is carried out by emulsion polymerization, among these radical polymerization initiators, inorganic peroxides such as water-soluble ammonium persulfate, potassium persulfate, and sodium persulfate, and azo compounds having a carboxyl group in the molecule such as water-soluble 4,4'-azobis-4-cyanovaleric acid are preferred. Considering the influence of ions on the surface of electronic components, azo compounds having a carboxyl group in the molecule such as ammonium persulfate and 4,4'-azobis-4-cyanovaleric acid are more preferred, and azo compounds having a carboxyl group in the molecule such as 4,4'-azobis-4-cyanovaleric acid are particularly preferred.

[0058] The adhesive resin layer (A) according to this embodiment preferably further contains, in addition to the adhesive resin (A1), a crosslinking agent (A2) having two or more crosslinkable functional groups per molecule. The crosslinking agent (A2) having two or more crosslinkable functional groups per molecule is reacted with the functional groups of the adhesive resin (A1) to adjust the adhesive strength and cohesive strength. 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, and resorcinol diglycidyl ether; isocyanate compounds such as tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate triadduct of trimethylolpropane, polyisocyanate, diphenylmethane diisocyanate, and tolylene diisocyanate; and trimethylolpropane-tri-β-aziridinylpropionate. Examples of suitable epoxy compounds include aziridine compounds such as 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-xylylenediamine and 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane; and melamine compounds such as hexamethoxymethylolmelamine. These compounds may be used alone or in combination of two or more. Among these, it is preferable to use one or more compounds selected from epoxy compounds, isocyanate compounds, and aziridine compounds.

[0059] The content of the crosslinking agent (A2) is usually preferably within a range such that the number of functional groups in the crosslinking agent (A2) is not greater than the number of functional groups in the adhesive resin (A1). However, an excess amount of the crosslinking agent (A2) may be added as necessary when new functional groups are generated in the crosslinking reaction or when the crosslinking reaction is slow. From the viewpoint of improving the balance between the heat resistance and adhesion of the adhesive resin layer (A), the content of the crosslinking agent (A2) in the adhesive resin layer (A) is preferably 0.1 parts by mass or more and 15 parts by mass or less per 100 parts by mass of the adhesive resin (A1).

[0060] The adhesive resin layer (A) may contain additives such as plasticizers and tackifying resins as other components. When the adhesive resin layer (A) is a radiation-crosslinkable adhesive resin layer, it may contain various additives for radiation crosslinking. The total content of the adhesive resin (A1) and the crosslinking agent (A2) in the adhesive resin layer (A) is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more, when the entire adhesive resin layer (A) is taken as 100% by mass. This further reduces adhesive residue on the electronic component when the adhesive film 50 is peeled off from the electronic component.

[0061] The thickness of the adhesive resin layer (A) is not particularly limited, but is preferably, for example, from 1 μm to 100 μm, and more preferably from 3 μm to 50 μm.

[0062] The adhesive resin layer (A) can be formed, for example, by applying an adhesive to the base layer 10. The adhesive may be dissolved in a solvent and applied as a coating liquid, or may be applied as an aqueous emulsion, or the liquid adhesive may be applied directly. Among these, an adhesive coating liquid dissolved in an organic solvent is preferred. The organic solvent is not particularly limited and may be appropriately selected from known solvents taking into account solubility and drying time. Examples of organic solvents include esters such as ethyl acetate and methyl acetate; ketones 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 alcohols such as isopropanol and butanol. Ethyl acetate and toluene are preferred as organic solvents. These solvents may be used alone or in combination. Conventional coating methods, such as a roll coater method, a reverse roll coater method, a gravure roll method, a bar coater method, a comma coater method, and a die coater method, can be used to apply the adhesive coating liquid. There are no particular restrictions on the drying conditions for the applied adhesive, but it is generally preferable to dry it for 10 seconds to 10 minutes at a temperature range of 80 to 200°C. It is more preferable to dry it for 15 seconds to 5 minutes at 80 to 170°C. After drying of the adhesive coating liquid is complete, it may be heated at 40 to 80°C for about 5 to 300 hours. The base layer 10 and the adhesive resin layer (A) may be formed by co-extrusion molding, or may be formed by laminating a film-like base layer 10 and a film-like adhesive resin layer (A).

[0063] (Adhesive Resin Layer (B)) The adhesive film 50 according to this embodiment includes an adhesive resin layer (B) on the second surface 10B side of the base layer 10 opposite to the first surface 10A.

[0064] The adhesive resin layer (B) preferably contains one or more selected from a (meth)acrylic adhesive resin, a silicone adhesive resin, a urethane adhesive resin, an olefin adhesive resin, and a styrene adhesive resin, and among these, more preferably contains a (meth)acrylic adhesive resin from the viewpoint of facilitating adjustment of adhesive strength.

[0065] The adhesive resin layer (B) preferably includes a self-releasing adhesive resin layer whose adhesive strength decreases with an external stimulus. This allows the adhesive film 50 to be easily peeled off from the support substrate 60 by applying an external stimulus. Examples of self-releasing adhesive resin layers whose adhesive strength decreases with an external stimulus include heat-releasing self-releasing adhesive resin layers whose adhesive strength decreases with heating, and radiation-releasing self-releasing adhesive resin layers whose adhesive strength decreases with radiation. Among these, heat-releasing self-releasing adhesive resin layers whose adhesive strength decreases with heating are preferred. Examples of heat-releasing self-releasing adhesive resin layers include adhesive resin layers composed of a heat-expandable adhesive containing a gas-generating component, a heat-expandable adhesive containing heat-expandable microspheres that can expand to reduce adhesive strength, and a heat-expandable adhesive whose adhesive strength decreases due to a crosslinking reaction of the adhesive component caused by heat.

[0066] The self-releasing adhesive resin layer preferably contains a thermally expandable adhesive, and the thermally expandable adhesive is preferably an adhesive whose adhesive strength is reduced or lost when heated at temperatures above 150°C. The reduction or loss of adhesive strength when heated at temperatures above 150°C can be evaluated, for example, by attaching the adhesive resin layer (B) side to a stainless steel plate, heating it at 140°C for 1 hour, and then heating it at a temperature above 150°C for 2 minutes, and then measuring the peel strength from the stainless steel plate. The specific heating temperature when heating at temperatures above 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 thermally expand, and is appropriately set depending on the type of gas generated and the type of thermally expandable microspheres. In this embodiment, loss of adhesive strength refers, for example, to a 180° peel strength of less than 0.5 N / 25 mm measured at 23°C and a tensile speed of 300 mm / min.

[0067] Examples of gas-generating components that can be used in thermally expandable pressure-sensitive adhesives include azo compounds, azide compounds, and Meldrum's acid derivatives. Other examples include inorganic blowing agents such as ammonium carbonate, ammonium bicarbonate, sodium bicarbonate, ammonium nitrite, sodium boron hydroxide, and various azides; water; fluorinated alkane compounds such as trichloromonofluoromethane and dichloromonofluoromethane; azo compounds such as azobisisobutyronitrile, azodicarbonamide, and barium azodicarboxylate; paratoluenesulfonylhydrazide, diphenylsulfone-3,3'-disulfonylhydrazide, 4,4'-oxybis(benzenesulfonyl)hydrazide; Other examples of organic blowing agents that can be used include hydrazine compounds such as p-toluenesulfonylsemicarbazide and 4,4'-oxybis(benzenesulfonylsemicarbazide); semicarbazide compounds such as p-toluenesulfonylsemicarbazide and 4,4'-oxybis(benzenesulfonylsemicarbazide); triazole compounds such as 5-morpholyl-1,2,3,4-thiatriazole; and N-nitroso compounds such as N,N'-dinitrosopentamethylenetetramine and N,N'-dimethyl-N,N'-dinitrosoterephthalamide. The gas-generating component may be added to the adhesive resin (B1) or may be directly bonded to the adhesive resin (B1).

[0068] The heat-expandable microspheres used in heat-expandable pressure-sensitive adhesives can be, for example, microencapsulated blowing agents. Examples of such heat-expandable microspheres include microspheres in which a substance that easily gasifies and expands upon heating, such as isobutane, propane, or pentane, is encapsulated within an elastic shell. Examples of materials constituting the shell include vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, and polysulfone. Heat-expandable microspheres can be produced, for example, by coacervation or interfacial polymerization. Heat-expandable microspheres can be added to adhesive resins.

[0069] The content of at least one selected from the gas-generating component and the heat-expandable microspheres can be appropriately set depending on the expansion ratio and adhesive strength reduction of the heat-peelable adhesive resin layer (B), and is not particularly limited, but is, for example, 1 to 150 parts by mass, preferably 10 to 130 parts by mass, and more preferably 12 to 100 parts by mass, per 100 parts by mass of the adhesive resin (B1) in the heat-peelable adhesive resin layer (B). It is preferable to design the temperature at which gas is generated or the temperature at which the heat-expandable microspheres thermally expand are above 150°C.

[0070] Examples of the adhesive resin (B1) constituting the thermally expandable adhesive include (meth)acrylic resin (b), urethane resin, silicone resin, polyolefin resin, polyester resin, polyamide resin, fluorine resin, styrene-diene block copolymer resin, etc. Among these, (meth)acrylic resin (b) is preferred.

[0071] The (meth)acrylic adhesive resin (b) used in the adhesive resin layer (B) may be, for example, a copolymer containing a (meth)acrylic acid alkyl ester monomer unit (b1) and a monomer unit (b2) having a functional group capable of reacting with a crosslinking agent. In this embodiment, the (meth)acrylic acid alkyl ester refers to an acrylic acid alkyl ester, a methacrylic acid alkyl ester, or a mixture thereof.

[0072] The (meth)acrylic adhesive resin (b) according to this embodiment can be obtained, for example, by copolymerizing a monomer mixture containing a (meth)acrylic acid alkyl ester monomer (b1) and a monomer (b2) having a functional group capable of reacting with a crosslinking agent.

[0073] 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 containing about 1 to 12 carbon atoms. (Meth)acrylic acid alkyl esters having an alkyl group containing 1 to 8 carbon atoms are preferred. Specific examples include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, and 2-ethylhexyl methacrylate. These may be used alone or in combination of two or more. In the (meth)acrylic adhesive resin (b) according to this 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 adhesive resin (b) is taken as 100% by mass.

[0074] Examples of the monomer (b2) that forms the monomer (b2) having a functional group reactive 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, tert-butylaminoethyl acrylate, and tert-butylaminoethyl methacrylate. Preferred are acrylic acid, methacrylic acid, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide, methacrylamide, and the like. These may be used alone or in combination of two or more. In the (meth)acrylic 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 adhesive resin (b) is 100% by mass.

[0075] The (meth)acrylic adhesive resin (b) according to this embodiment may further contain, in addition to the monomer unit (b1) and the monomer unit (b2), a bifunctional monomer unit (b3) or a specific comonomer unit having surfactant properties (hereinafter referred to as a polymerizable surfactant). The polymerizable surfactant has the property of copolymerizing with the monomer (b1), the monomer (b2), and the monomer (b3), and also acts as an emulsifier when emulsion polymerization is performed.

[0076] Examples of the monomer (b3) forming 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, diacrylates or acrylates having both ends thereof. or dimethacrylates whose main chain structure is a propylene glycol type (for example, NOF Corporation, trade names: PDP-200, PDP-400, ADP-200, ADP-400), a tetramethylene glycol type (for example, NOF Corporation, trade names: ADT-250, ADT-850), or a mixture thereof (for example, NOF Corporation, trade names: ADET-1800, ADPT-4000).

[0077] In the (meth)acrylic adhesive resin (b) according to the present 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 15% by mass or less, even 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 adhesive resin (b) is 100% by mass.

[0078] Examples of the polymerizable surfactant include those in which a polymerizable 1-propenyl group has been introduced into the benzene ring of polyoxyethylene nonylphenyl ether (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.; trade names: AQUALON RN-10, RN-20, RN-30, RN-50, etc.), those in which a polymerizable 1-propenyl group has been introduced into the benzene ring of an ammonium salt of a sulfate ester of polyoxyethylene nonylphenyl ether (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.; trade names: AQUALON HS-10, HS-20, HS-1025, etc.), and sulfosuccinic acid diesters having a polymerizable double bond in the molecule (manufactured by Kao Corporation; trade names: Latemul S-120A, S-180A, etc.). In the (meth)acrylic adhesive resin (b) according to the present embodiment, 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, even 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 sum of all monomer units in the (meth)acrylic adhesive resin (b) is 100% by mass.

[0079] The (meth)acrylic adhesive resin (b) according to the present embodiment may further contain, as necessary, a monomer unit formed from a monomer having a polymerizable double bond, such as vinyl acetate, acrylonitrile, or styrene.

[0080] The polymerization reaction mechanism of the (meth)acrylic adhesive resin (b) according to this embodiment may be radical polymerization, anionic polymerization, cationic polymerization, or the like. Taking into consideration the production cost of the (meth)acrylic adhesive resin (b), the influence of the functional groups of the monomer, and the influence of ions on the surface of electronic components, polymerization by radical polymerization is preferred. When polymerization is carried out by radical polymerization, the radical polymerization initiator may be selected from the group consisting of 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-butylperoxy-2-hexanoate, t-butyl peroxy, and the like. Examples of the peroxide include organic peroxides such as 2-ethylhexanoate, t-butylperoxy-3,5,5-trimethylhexanoate, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, t-butyl peroxide, and di-t-amyl peroxide; inorganic peroxides such as ammonium persulfate, potassium persulfate, and sodium persulfate; and azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, and 4,4'-azobis-4-cyanovaleric acid.

[0081] When polymerization is carried out by emulsion polymerization, among these radical polymerization initiators, inorganic peroxides such as water-soluble ammonium persulfate, potassium persulfate, and sodium persulfate, and azo compounds having a carboxyl group in the molecule such as water-soluble 4,4'-azobis-4-cyanovaleric acid are preferred. Considering the influence of ions on the surface of electronic components, azo compounds having a carboxyl group in the molecule such as ammonium persulfate and 4,4'-azobis-4-cyanovaleric acid are more preferred, and azo compounds having a carboxyl group in the molecule such as 4,4'-azobis-4-cyanovaleric acid are particularly preferred.

[0082] The adhesive resin layer (B) according to this embodiment preferably further contains, in addition to the adhesive resin (B1), a crosslinking agent (B2) having two or more crosslinkable functional groups per molecule. The crosslinking agent (B2) having two or more crosslinkable functional groups per molecule is reacted with the functional groups of the adhesive resin (B1) to adjust the adhesive strength and cohesive strength. 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, and resorcinol diglycidyl ether; isocyanate compounds such as tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate triadduct of trimethylolpropane, polyisocyanate, diphenylmethane diisocyanate, and tolylene diisocyanate; and trimethylolpropane-tri-β-aziridinylpropionate. Examples of suitable epoxy compounds include aziridine compounds such as 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-xylylenediamine and 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane; and melamine compounds such as hexamethoxymethylolmelamine. These compounds may be used alone or in combination of two or more. Among these, it is preferable to use one or more compounds selected from epoxy compounds, isocyanate compounds, and aziridine compounds.

[0083] The content of the crosslinking agent (B2) is usually preferably within a range such that the number of functional groups in the crosslinking agent (B2) is not greater than the number of functional groups in the adhesive resin (B1). However, if necessary, an excess amount of the crosslinking agent (B2) may be added when new functional groups are generated in the crosslinking reaction or when the crosslinking reaction is slow. The content of the crosslinking agent (B2) in the adhesive resin layer (B) is preferably 0.1 parts by mass or more and 10 parts by mass or less, more preferably 0.5 parts by mass or more and 5 parts by mass or less, per 100 parts by mass of the adhesive resin (B1).

[0084] From the viewpoint of improving adhesion to the support substrate 60, the adhesive resin layer (B) according to this embodiment preferably contains a tackifier resin in addition to the adhesive resin (B1). Inclusion of a tackifier resin in the adhesive resin layer (B) is preferred because it facilitates adjustment of adhesion to the support substrate 60 at around room temperature. The tackifier resin preferably has a softening point of 100°C or higher. Specific examples of tackifier resins include rosin-based resins such as rosin derivatives that have been treated with esterification or the like; terpene-based resins such as α-pinene-based, β-pinene-based, dipentene-based, and terpene phenol-based resins; natural rosins such as gum-based, wood-based, and tall oil-based rosins; hydrogenated, disproportionated, polymerized, maleated, and petroleum resins of these natural rosins; and coumarone-indene resins.

[0085] 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. Using a tackifier resin having a softening point within the above range not only reduces contamination and adhesive residue on the support substrate 60, but also enables further improved adhesion to the support substrate 60 in the working environment. Furthermore, using a polymerized rosin ester-based tackifier resin as the tackifier resin not only reduces contamination and adhesive residue on the support substrate 60, but also improves adhesion to the support substrate 60 in an environment of 80 to 130°C, and in the case of a heat-expandable pressure-sensitive adhesive containing heat-expandable microspheres, it becomes even easier to peel the adhesive from the support substrate 60 after the heat-expandable microspheres expand.

[0086] The blending ratio of the tackifier resin is not particularly limited, and may be appropriately selected so as to adjust the elastic modulus of the adhesive resin layer (B) within the desired predetermined numerical range. However, in terms of the elastic modulus and initial peel strength of the adhesive resin layer (B), a blending ratio of 1 to 100 parts by mass per 100 parts by mass of the adhesive resin (B1) is preferred. When the blending ratio of the tackifier resin is equal to or greater than the lower limit per 100 parts by mass of the adhesive resin (B1), adhesion to the support substrate 60 during operation tends to be improved. On the other hand, when the blending ratio is equal to or less than the upper limit, attachment to the support substrate 60 at room temperature tends to be improved. In terms of adhesion to the support substrate 60 and attachment at room temperature, a blending ratio of the tackifier resin of 2 to 50 parts by mass per 100 parts by mass of the adhesive resin (B1) is more preferred. Furthermore, the acid value of the tackifier resin is preferably 30 or less. When the acid value of the tackifier resin is equal to or less than the upper limit, adhesive residue on the support substrate 60 tends to be less likely to be left during peeling.

[0087] The adhesive resin layer (B) may contain additives such as plasticizers as other components. The total content of the adhesive resin (B1), crosslinking agent (B2), and tackifier resin in the adhesive resin layer (B) is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more, when the entire adhesive resin layer (B) is taken as 100% by mass. Furthermore, when the adhesive resin layer (B) is composed of a heat-expandable adhesive, the total content of the adhesive resin (B1), crosslinking agent (B2), tackifier resin, gas-generating component, and heat-expandable microspheres in the adhesive resin layer (B) is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more, when the entire adhesive resin layer (B) is taken as 100% by mass.

[0088] The thickness of the adhesive resin layer (B) is not particularly limited, but is preferably, for example, from 5 μm to 300 μm, and more preferably from 20 μm to 150 μm.

[0089] The adhesive resin layer (B) can be formed, for example, by applying an adhesive coating liquid onto the base layer 10, or by transferring the adhesive resin layer (B) formed on a separator onto the base layer 10. Conventional coating methods, such as roll coating, reverse roll coating, gravure roll coating, bar coating, comma coating, and die coating, can be used to apply the adhesive coating liquid. While there are no particular limitations on the drying conditions for the applied adhesive, drying at a temperature range of 80 to 200°C for 10 seconds to 10 minutes is generally preferred. Drying at 80 to 170°C for 15 seconds to 5 minutes is more preferred. To sufficiently promote the crosslinking reaction between the crosslinker and the adhesive, the adhesive coating liquid may be heated at 40 to 80°C for approximately 5 to 300 hours after drying. The base material layer 10 and the adhesive resin layer (B) may be formed by co-extrusion molding, or may be formed by laminating a film-like base material layer 10 and a film-like adhesive resin layer (B).

[0090] (Other Layers) The adhesive film 50 according to this embodiment may further include, for example, an irregularity absorbing layer, an impact absorbing layer, an easy-adhesion layer, etc., 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), within a range that does not impair the effects of this embodiment.

[0091] The unevenness-absorbing layer is preferably formed from natural rubber or synthetic rubber, or a synthetic resin having rubber elasticity, having a Shore D hardness according to ASTM D-2240 Shore D hardness of, for example, 50 or less, preferably 40 or less. The thickness of the unevenness-absorbing layer is, for example, 500 μm or less, preferably 5 to 300 μm, and more preferably 10 to 150 μm.

[0092] Examples of synthetic rubbers or synthetic resins include nitrile-based, diene-based, and acrylic-based synthetic rubbers, polyolefin-based and polyester-based thermoplastic elastomers, and synthetic resins having rubber elasticity such as ethylene-vinyl acetate copolymers, polyurethanes, polybutadiene, and soft polyvinyl chloride. In this embodiment, even essentially hard polymers such as polyvinyl chloride can be used that have rubber elasticity due to the addition of additives such as plasticizers and softeners. Furthermore, the adhesive resins exemplified for the adhesive resin layer (A) and the adhesive resin layer (B) can also be preferably used to form the irregularity-absorbing layer.

[0093] (Thickness of Adhesive Film 50) From the viewpoint of the balance between mechanical properties and handleability, the overall thickness of the adhesive film 50 according to this embodiment is preferably 10 μm or more and 1000 μm or less, more preferably 20 μm or more and 500 μm or less.

[0094] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations can also be adopted.

[0095] The present invention is not limited to the above-described embodiment, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention.

[0096] A: adhesive resin layer B: adhesive resin layer 10: base layer 10A: first surface 10B: second surface 50: adhesive film 60: supporting substrate 70: resist pattern 80: wiring layer 100: structural body

Claims

1. A method for manufacturing an electronic device, comprising: a step of preparing a structure having a support substrate and an adhesive film attached to the support substrate; a step of forming a resist pattern on the adhesive film using a resist; a step of forming a wiring layer on the adhesive film by electroless plating; and a step of removing the resist pattern.

2. The method for manufacturing an electronic device according to claim 1, wherein the wiring layer is formed without an etching process.

3. The method for manufacturing an electronic device according to claim 1 or 2, further comprising the step of mounting electronic components on the wiring layer.

4. The method for manufacturing an electronic device according to claim 3, further comprising the step of sealing the electronic components mounted on the wiring layer with a sealing material.

5. The method for manufacturing an electronic device according to claim 4, wherein the adhesive resin layer (B) includes a layer whose adhesive strength is reduced by an external stimulus, and further comprising, after the sealing step, a first peeling step of applying an external stimulus to reduce the adhesive strength of the adhesive resin layer (B) and peeling the adhesive film from the support substrate or the wiring layer.

6. The method for manufacturing an electronic device according to claim 5, further comprising a second peeling step of peeling the adhesive film from the support substrate or the wiring layer after the first peeling step.

7. The method for manufacturing an electronic device according to any one of claims 1 to 6, wherein the electronic device comprises a fan-out type package.

8. A method for manufacturing an electronic device according to any one of claims 1 to 7, wherein the adhesive film comprises a base layer, an adhesive resin layer (A) provided on a first surface of the base layer, and an adhesive resin layer (B) provided on a second surface of the base layer, at least one of the adhesive resin layer (A) or the adhesive resin layer (B) contains a reducing agent, and the wiring layer is formed on the surface of the adhesive resin layer (A) or the adhesive resin layer (B) on which the layer containing the reducing agent is provided.

9. The method for producing an electronic device according to claim 8, wherein the reducing agent comprises one or more elements selected from the group consisting of iron, cobalt, nickel, tin, copper, silver, palladium, iridium, platinum, and gold.

10. The method for manufacturing an electronic device according to claim 9, wherein the reducing agent comprises palladium.

11. The method for producing an electronic device according to claim 10, wherein the reducing agent comprises one or more selected from the group consisting of elemental palladium and palladium halides.

12. A method for manufacturing an electronic device according to any one of claims 8 to 11, wherein at least one of the adhesive resin layer (A) and the adhesive resin layer (B) contains one or more types selected from the group consisting of (meth)acrylic adhesive resins, silicone adhesive resins, urethane adhesive resins, olefin adhesive resins, and styrene adhesive resins.

13. The method for manufacturing an electronic device according to any one of claims 8 to 12, wherein the adhesive resin layer (B) includes a self-peeling adhesive resin layer whose adhesive strength decreases in response to an external stimulus.

14. The method for manufacturing an electronic device according to claim 13, wherein the self-peeling adhesive resin layer contains a thermal expansion adhesive, and the thermal expansion adhesive is an adhesive whose adhesive strength is reduced or lost when heated at a temperature exceeding 150°C.

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