Method for producing electronic device

Abstract

This method for producing an electronic device includes: a preparation step for preparing an adhesive film (50) comprising a base material layer (10), an adhesive resin layer (A) that is provided on a first surface side of the base material layer (10) and serves to temporarily fix an electronic component (70), and an adhesive resin layer (B) provided on a second surface side of the base material layer (10), and a structure (100) comprising 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); and a sealing step for sealing the electronic component (70) by means of a sealing material (60). The method also includes an air removal step for removing air pockets in the structure (100) between the preparation step and the sealing step.

Description

Manufacturing method of electronic device

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

[0002] Fan-out packaging has been developed as a technology that can reduce the size and weight of electronic devices (e.g., semiconductor devices). One method for fabricating fan-out packaging, called embedded wafer-level ball grid array (eWLB), involves temporarily fixing multiple electronic components, such as semiconductor chips, spaced apart on an adhesive film attached to a support substrate, and then encapsulating the multiple electronic components together with an encapsulant. Here, the adhesive film must be adhered to the electronic components and the support substrate during the encapsulation process, and must be removed from the encapsulated electronic components together with the support substrate after encapsulation.

[0003] As a technique relating to a manufacturing method of such a fan-out type package, 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] According to the investigations of the present inventors, it has become clear that when electronic components are placed on an adhesive film and sealed with a sealant, the electronic components may become misaligned (hereinafter also referred to as "misalignment of electronic components"). The present invention has been made in view of the above circumstances, and provides a method for manufacturing an electronic device that can suppress misalignment of electronic components during the sealing process.

[0007] According to the present invention, there is provided a method for manufacturing an electronic device as follows.

[0008] [1] A method for manufacturing an electronic device, comprising: a preparation step of preparing a structure including a substrate layer, an adhesive film including: a substrate layer; an adhesive resin layer (A) provided on a first surface of the substrate layer for temporarily fixing an electronic component; and an adhesive resin layer (B) provided on a second surface of the substrate layer; an electronic component attached to the adhesive resin layer (A) of the adhesive film; and a support substrate attached to the adhesive resin layer (B) of the adhesive film; and a sealing step of sealing the electronic component with a sealing material, the method comprising: an air removal step of removing air trapped in the structure between the preparation step and the sealing step. [2] The method for manufacturing an electronic device according to [1] above, wherein the air removal step places the structure in a reduced pressure environment. [3] The method for manufacturing an electronic device according to [1] above, wherein the air removal step involves laminating an electronic component fixing member on the electronic component of the structure. [4] The method for producing an electronic device according to [3] above, wherein the structure in which the electronic component-fixing members are stacked is heated in the air removal step. [5] The method for producing an electronic device according to [3] or [4] above, wherein the structure in which the electronic component-fixing members are stacked is pressurized in the air removal step. [6] The method for producing an electronic device according to any one of [3] to [5] above, wherein the electronic component-fixing member contains polyolefin. [7] The method for producing an electronic device according to any one of [3] to [6] above, wherein the electronic component-fixing member is in the form of a film. [8] The method for producing an electronic device according to any one of [1] to [7] above, wherein the heating temperature in the air removal step is less than 70°C. [9] The method for producing an electronic device according to any one of [1] to [8] above, wherein the heating time in the air removal step is less than 5 minutes.

[10] The method for producing an electronic device according to any one of [1] to [9] above, further comprising a moisture removal step of removing moisture from the structure after the air removal step.

[11] The method for manufacturing an electronic device according to any one of [1] to

[10] above, wherein in the sealing step, the electronic components are sealed 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.

[12] The method for manufacturing an electronic device according to any one of [1] to

[11] above, wherein the adhesive resin layer (B) is a layer whose adhesive strength is reduced by an external stimulus, and further comprising, after the sealing step, a first peeling step of reducing the adhesive strength of the adhesive resin layer (B) by applying an external stimulus to peel the support substrate from the structure.

[13] The method for manufacturing an electronic device according to

[12] above, further comprising, after the first peeling step, a second peeling step of peeling the adhesive film from the electronic component.

[14] The method for manufacturing an electronic device according to any one of [1] to

[13] above, wherein the adhesive resin constituting the adhesive resin layer (A) comprises 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.

[15] The method for manufacturing an electronic device according to any one of [1] to

[14] above, wherein the adhesive resin layer (B) contains a thermally expandable adhesive, and the thermally expandable adhesive is an adhesive whose adhesive strength decreases or is lost when heated at a temperature exceeding 150° C.

[16] The method for manufacturing an electronic device according to any one of [1] to

[15] above, wherein the encapsulant contains an epoxy resin-based encapsulant.

[17] The method for manufacturing an electronic device according to any one of [1] to

[16] above, wherein the electronic device includes a fan-out type package.

[0009] According to the present invention, it is possible to provide a method for manufacturing an electronic device that can suppress misalignment of electronic components during the sealing process.

[0010] Fig. 1 is a cross-sectional view schematically showing an example of the structure of an adhesive film according to an embodiment of the present invention. Fig. 2 is a cross-sectional view schematically showing an example of a method for manufacturing an electronic device according to an embodiment of the present invention. Fig. 3 is a cross-sectional view schematically showing an example of a method for manufacturing an electronic device according to an embodiment of the present invention. Fig. 4 is a cross-sectional view schematically showing a state in which an electronic component fixing member is laminated on an electronic component of a structure according to the present invention.

[0011] 1. Method for Manufacturing an Electronic Device A method for manufacturing an electronic device according to this embodiment will now be described.

[0012] First, a method for manufacturing an electronic device according to this embodiment will be described. FIG. 1 is a cross-sectional view schematically illustrating an example of the structure of an adhesive film 50 according to this embodiment. FIGS. 2 and 3 are cross-sectional views schematically illustrating an example of a method for manufacturing an electronic device according to this embodiment. The method for manufacturing an electronic device according to this embodiment includes at least the following three steps. (1) A preparation step of preparing a structure 100 including a base layer 10, an adhesive film 50 including an adhesive resin layer (A) provided on the first surface 10A of the base layer 10 and for temporarily fixing an electronic component 70, and an adhesive resin layer (B) provided on the second surface 10B of the base layer 10, the 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) An air removal step of removing air pockets in the structure 100. (3) A sealing step of sealing the electronic component 70 with a sealant 60.

[0013] As described above, the inventors' studies have revealed that when electronic components are placed on an adhesive film and sealed with a sealing material, the electronic components may become misaligned (hereinafter also referred to as "misalignment of electronic components"). The inventors conducted extensive research to achieve the above-mentioned object. As a result, they found that, during the process of sealing the electronic components, the electronic components are unable to withstand the pressure caused by the flow of the sealing material, resulting in misalignment of the electronic components. Furthermore, they found that air pockets formed in the structure 100, particularly air pockets formed between the electronic components 70 and the adhesive film 50, reduce the adhesion between the electronic components 70 and the adhesive film 50, thereby causing misalignment of the electronic components 70. Based on the above findings, the inventors conducted further research. As a result, they discovered for the first time that removing the air pockets in the structure 100 before the sealing process maintains the adhesion between the electronic components 70 and the adhesive film 50, thereby suppressing misalignment of the electronic components 70 during the sealing process. That is, according to the method for manufacturing an electronic device of this embodiment, by removing air pockets in structure 100 before the sealing step, adhesion between electronic component 70 and adhesive film 50 is maintained, and therefore, it is possible to prevent electronic component 70 from being displaced due to pressure caused by the flow of sealing material 60 in the step of sealing electronic component 70. As described above, according to the method for manufacturing an electronic device of this embodiment, it is possible to prevent electronic component 70 from being displaced in the sealing step.

[0014] Each step of the method for manufacturing an electronic device according to this embodiment will be described below.

[0015] ((1) Preparation Step) In the preparation step, a structure 100 is prepared, which includes 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.

[0016] Such a structure 100 can be produced, for example, by the following procedure. First, the adhesive film 50 is attached to the support substrate 80 so that the adhesive resin layer (B) faces the support substrate 80. A protective film called a separator may be attached to the adhesive resin layer (B), and the protective film can be peeled off, allowing the exposed surface of the adhesive resin layer (B) to be attached to the surface of the support substrate 80. As the support substrate 80, for example, a quartz substrate, a glass substrate, a SUS substrate, or the like can be used.

[0017] Next, the structure 100 can be obtained by placing the electronic component 70 on the adhesive resin layer (A) of the adhesive film 50 attached to the support substrate 80. Examples of the electronic component 70 include semiconductor chips such as ICs, LSIs, discrete devices, light-emitting diodes, and light-receiving elements, semiconductor panels, and semiconductor packages.

[0018] ((2) Air Removal Step) The air removal step will be described below.

[0019] In the air removal step, it is preferable to place the structure 100 in a reduced pressure environment. This removes air trapped between the adhesive film 50 and the electronic component 70, further suppressing misalignment of the electronic component 70 in the sealing step. The degree of pressure reduction when placing the structure 100 in a reduced pressure environment is not particularly limited, but is preferably 1.0 × 10 ５ Pa or less, more preferably 5.0 × 10 ４ Pa or less, more preferably 1.0 × 10 ４ Pa or less, more preferably 5.0 × 10 ３ Pa or less, for example, 1.0×10 －２ Pa or more, preferably 1.0 Pa or more, more preferably 1.0 x 10 ２ Pa or more.

[0020] In the air removal step, it is preferable to laminate an electronic component fixing member 110 on the electronic component 70 of the structure 100, as shown in Fig. 4. This allows the electronic component fixing member 110 to be in close contact with the adhesive film 50, with the electronic component 70 sandwiched between the electronic component fixing member 110 and the adhesive film 50. This removes air pockets that have formed between the adhesive film 50 and the electronic component 70, further suppressing misalignment of the electronic component 70 during the sealing step.

[0021] In the air removal step, it is preferable to heat the structure 100 in which the electronic component-fixing members 110 are laminated. This causes the electronic component-fixing members 110 to adhere more closely to the adhesive film 50, and air pockets that have formed between the adhesive film 50 and the electronic component 70 are more effectively removed, thereby further suppressing displacement of the electronic component 70 during the sealing step.

[0022] In the air removal step, it is preferable to apply pressure to the structure 100 in which the electronic component-fixing members 110 are laminated. This causes the electronic component-fixing members 110 to adhere more closely to the adhesive film 50, and air pockets that have formed between the adhesive film 50 and the electronic component 70 are more effectively removed, thereby further suppressing displacement of the electronic component 70 during the sealing step.

[0023] The electronic component fixing member 110 preferably contains a thermoplastic resin, and more preferably contains one or more polyolefins selected from the group consisting of polyethylene, polypropylene, poly(4-methyl-1-pentene), poly(1-butene), etc. This allows the electronic component fixing member 110 to adhere more closely to the adhesive film 50, further removing air pockets that may have formed between the adhesive film 50 and the electronic component 70, and further suppressing displacement of the electronic component 70 during the sealing process.

[0024] The electronic component fixing member 110 is preferably in the form of a film, which makes it easier to laminate onto the structure 100 and also easier to remove from the structure 100 after the air removal step is completed.

[0025] After the air removal step is completed, the electronic component fixing member 110 is removed from the structure 100 .

[0026] The air removal step may involve heating the structure 100 .

[0027] The heating temperature in the air removal step is not particularly limited, but from the viewpoint of more efficiently removing air pockets that have formed between the adhesive film 50 and the electronic component 70, it is preferably 30°C or higher, more preferably 35°C or higher, more preferably 40°C or higher, even more preferably 45°C or higher, even more preferably 50°C or higher, even more preferably 55°C or higher, even more preferably 60°C or higher, and even more preferably 65°C or higher; and from the viewpoint of preventing deterioration of components such as the electronic component fixing member 110 and the adhesive film 50, and from the viewpoint of suppressing thermal expansion of the adhesive film 50 if the adhesive film 50 is a thermal expansion type, it is preferably less than 150°C, more preferably less than 100°C, even more preferably less than 90°C, even more preferably less than 70°C, even more preferably less than 68°C, and even more preferably less than 67°C.

[0028] The heating time in the air removal step is not particularly limited, but is, for example, 1 second or more, and from the viewpoint of preventing deterioration of components such as the electronic component fixing member 110 and the adhesive film 50, and from the viewpoint of suppressing thermal expansion of the adhesive film 50 if the adhesive film 50 is of a thermal expansion type, it is preferably less than 5 minutes, more preferably less than 3 minutes, even more preferably less than 1 minute, even more preferably less than 30 seconds, and even more preferably less than 10 seconds.

[0029] The method for heating the structure 100 is not particularly limited, but for example, a commonly known heat treatment method such as an oven, a dryer, a heating roll, or a drying furnace can be used.

[0030] ((3) Sealing Step) Next, the electronic component 70 is sealed with the sealing material 60. The electronic component 70 is covered with the sealing material 60, and the sealing material 60 is cured at a temperature of, for example, 150° C. or less to seal the electronic component 70. The form of the sealing material 60 is not particularly limited, and may be, for example, granular, sheet-like, or liquid.

[0031] The components of the sealing material 60 are not particularly limited, but preferably include an epoxy resin-based sealing material, and more preferably include a liquid epoxy resin-based sealing material, from the viewpoint of improving the affinity of the sealing material 60 to the adhesive film 50 and enabling more uniform sealing of the electronic component 70. Examples of such epoxy resin-based sealing materials that can be used include the T693 / R4000 series, T693 / R1000 series, and T693 / R5000 series manufactured by Nagase ChemteX Corporation.

[0032] The sealing method in the sealing step is not particularly limited, but it is preferable to seal the electronic component 70 with the sealing material 60 using one or more molding methods selected from the group consisting of transfer molding, injection molding, compression molding, and cast molding.

[0033] After sealing the electronic component 70 with the sealing material 60, the sealing material 60 can be hardened by heating at a temperature of, for example, 150°C or less, thereby obtaining a structure 100 in which the electronic component 70 is sealed.

[0034] (Other Steps) The method for manufacturing an electronic device according to this embodiment may further include steps other than the preparation step (1), the air removal step (2), and the sealing step (3).

[0035] The method for manufacturing an electronic device according to this embodiment preferably further includes, after the air removal step (2), a moisture removal step of removing moisture from the structure 100. This reduces the amount of moisture in the structure 100, and prevents moisture-related deterioration of the electronic component 70.

[0036] The method for removing moisture in the moisture removal step is not particularly limited, and any method may be used, such as drying by heating, drying under reduced pressure, or drying with a desiccant.

[0037] When drying is performed by heating, the heating temperature is not particularly limited, but from the viewpoint of more reliably removing moisture, it is preferably 70°C or higher, more preferably 80°C or higher, even more preferably 90°C or higher, and even more preferably 100°C or higher, and is, for example, less than 150°C.

[0038] When drying is performed by heating, the heating time is not particularly limited, but from the viewpoint of more reliably removing moisture, it is preferably 5 minutes or more, more preferably 10 minutes or more, even more preferably 20 minutes or more, even more preferably 30 minutes or more, even more preferably 1 hour or more, and is, for example, less than 3 hours.

[0039] 3, the method for manufacturing an electronic device according to this embodiment may further include a first peeling step (4) after the sealing step (3) in which an external stimulus is applied to reduce the adhesive strength of the adhesive resin layer (B) and peel the support substrate 80 from the structure 100. For example, after sealing the electronic component 70, the support substrate 80 can be easily removed from the adhesive film 50 by heating the support substrate 80 to a temperature exceeding 150°C to reduce the adhesive strength of the adhesive resin layer (B).

[0040] 3, the method for manufacturing an electronic device according to this embodiment may further include a second peeling step (5) after the first peeling step (4) in which the adhesive film 50 is peeled off from the electronic component 70 to obtain the electronic device 200. Examples of methods for peeling the adhesive film 50 from the electronic component 70 include a mechanical peeling method and a method in which the adhesive strength of the surface of the adhesive film 50 is reduced before peeling.

[0041] The method for manufacturing an electronic device according to this embodiment may further include a step (6) of forming a wiring layer 310 and bumps 320 on the exposed surface of the obtained electronic device 200, as shown in FIG. 3, to obtain the electronic device 300.

[0042] The wiring layer 310 includes pads (not shown) that are external connection terminals formed on the outermost surface, and wiring (not shown) that electrically connects the pads to the exposed electronic components 70. The wiring layer 310 can be formed by a conventionally known method, and may have a multi-layer structure.

[0043] Then, bumps 320 are formed on the pads of the wiring layer 310, thereby obtaining the electronic device 300. Examples of the bumps 320 include solder bumps and gold bumps. Solder bumps can be formed, for example, by placing solder balls on pads that serve as external connection terminals of the wiring layer 310 and heating them to melt the solder (reflow). Gold bumps can be formed by methods such as ball bonding, plating, and Au ball transfer.

[0044] 3, the method for manufacturing an electronic device according to this embodiment may further include a step (7) of dicing the electronic device 300 to obtain a plurality of electronic devices 400. The dicing of the electronic device 300 can be performed by a known method.

[0045] The type of electronic device 300 is not particularly limited, but preferably includes a fan-out type package. A fan-out type package allows terminals to 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 be made thinner.

[0046] 2. Adhesive Film The adhesive film 50 according to this embodiment will now be described. Fig. 1 is a cross-sectional view schematically showing an example of the structure of an adhesive film 50 according to an embodiment of the present invention.

[0047] As shown in FIG. 1, the adhesive film 50 according to this embodiment 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.

[0048] The total 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, from the viewpoint of the balance between mechanical properties and handling properties.

[0049] Next, each layer constituting the adhesive film 50 according to this embodiment will be described.

[0050] <Substrate Layer> 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.

[0051] 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.

[0052] 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.

[0053] <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 the electronic component 70 to temporarily fix the electronic component 70 when, for example, the electronic component 70 is sealed with the sealing material 60 in the manufacturing process of the electronic device.

[0054] The adhesive resin (A1) constituting the adhesive resin layer (A) preferably contains one or more selected from (meth)acrylic adhesive resins, silicone adhesive resins, urethane adhesive resins, olefin adhesive resins, and styrene adhesive resins, and among these, more preferably contains a (meth)acrylic adhesive resin (a) from the viewpoint of facilitating adjustment of adhesive strength.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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).

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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 the electronic component 70, 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.

[0065] When polymerization is performed 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 component 70, 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.

[0066] 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.

[0067] 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).

[0068] 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 70 when the adhesive film 50 is peeled from the electronic component 70.

[0069] 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.

[0070] 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).

[0071] <Adhesive Resin Layer (B)> The adhesive film 50 according to this embodiment includes an adhesive resin layer (B) on the second surface 10B of the base layer 10, opposite the first surface 10A. The adhesive resin layer (B) preferably has a function of reducing its adhesive strength in response to an external stimulus. This allows the adhesive film 50 to be easily peeled off from the support substrate 80 by applying an external stimulus. Examples of the adhesive resin layer (B) whose adhesive strength is reduced in response to an external stimulus include a heat-peelable adhesive resin layer whose adhesive strength is reduced by heating, and a radiation-peelable adhesive resin layer whose adhesive strength is reduced by radiation. Among these, a heat-peelable adhesive resin layer whose adhesive strength is reduced by heating is preferred. Examples of heat-peelable 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 expand to reduce its adhesive strength, and a heat-expandable adhesive whose adhesive strength is reduced by a crosslinking reaction of the adhesive component due to heat.

[0072] The adhesive resin layer (B) preferably contains a thermally expandable adhesive, and more preferably, the thermally expandable adhesive is an adhesive whose adhesive strength is reduced or lost when heated at temperatures exceeding 150°C. The reduction or loss of adhesive strength when heated at temperatures exceeding 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 exceeding 150°C for 2 minutes, and then measuring the peel strength from the stainless steel plate. The specific heating temperature when heating at temperatures 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 thermally expand, and is appropriately set depending on the 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.

[0073] 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).

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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).

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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 the electronic component 70, 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.

[0087] When polymerization is performed 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 component 70, 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.

[0088] 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.

[0089] 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).

[0090] From the viewpoint of improving adhesion to the support substrate 80, 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 80 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.

[0091] 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 80, but also enables further improved adhesion to the support substrate 80 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 80, but also improves adhesion to the support substrate 80 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 80 after the heat-expandable microspheres expand.

[0092] 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 80 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 80 at room temperature tends to be improved. In terms of adhesion to the support substrate 80 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 80 tends to be less likely to be left during peeling.

[0093] 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.

[0094] 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.

[0095] 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).

[0096] <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, or the like, 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.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] A: Adhesive resin layer B: Adhesive resin layer 10: Base layer 10A: First surface 10B: Second surface 50: Adhesive film 60: Sealing material 70: Electronic component 80: Support substrate 100: Structure 110: Electronic component fixing member 200: Electronic device 300: Electronic device 310: Wiring layer 320: Bump 400: Electronic device

Claims

1. A method for manufacturing an electronic device, comprising: a preparation step of preparing a structure comprising: an adhesive film comprising a base layer, an adhesive resin layer (A) provided on a first surface of the base layer for temporarily fixing an electronic component, and an adhesive resin layer (B) provided on a second surface of the base layer; an electronic component attached to the adhesive resin layer (A) of the adhesive film; and a support substrate attached to the adhesive resin layer (B) of the adhesive film; and a sealing step of sealing the electronic component with a sealing material, wherein the method further comprises an air removal step of removing air pockets in the structure between the preparation step and the sealing step.

2. The method for manufacturing an electronic device according to claim 1, wherein the structure is placed in a reduced pressure environment in the air removal step.

3. The method for manufacturing an electronic device according to claim 1 or 2, wherein in the air removal step, an electronic component fixing member is laminated on the electronic component of the structure.

4. The method for manufacturing an electronic device according to claim 3, wherein the structure in which the electronic component fixing members are stacked is heated in the air removal step.

5. The method for manufacturing an electronic device according to claim 3 or 4, wherein the structure in which the electronic component fixing members are stacked is pressurized in the air removal step.

6. The method for manufacturing an electronic device according to any one of claims 3 to 5, wherein the electronic component fixing member contains polyolefin.

7. The method for manufacturing an electronic device according to any one of claims 3 to 6, wherein the electronic component fixing member is in the form of a film.

8. The method for manufacturing an electronic device according to any one of claims 1 to 7, wherein the heating temperature in the air removal step is less than 70°C.

9. The method for manufacturing an electronic device according to any one of claims 1 to 8, wherein the heating time in the air removal step is less than 5 minutes.

10. The method for manufacturing an electronic device according to any one of claims 1 to 9, further comprising a moisture removal step of removing moisture from the structure after the air removal step.

11. A method for manufacturing an electronic device according to any one of claims 1 to 10, wherein in the sealing step, the electronic components are sealed 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.

12. A method for manufacturing an electronic device according to any one of claims 1 to 11, wherein the adhesive resin layer (B) is a layer whose adhesive strength decreases in response to 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 support substrate from the structure.

13. The method for manufacturing an electronic device according to claim 12, further comprising a second peeling step of peeling the adhesive film from the electronic component after the first peeling step.

14. A method for manufacturing an electronic device according to any one of claims 1 to 13, wherein the adhesive resin constituting the adhesive resin layer (A) comprises one or more selected from the group consisting of (meth)acrylic adhesive resins, silicone adhesive resins, urethane adhesive resins, olefin adhesive resins, and styrene adhesive resins.

15. A method for manufacturing an electronic device according to any one of claims 1 to 14, wherein the adhesive resin layer (B) contains a thermally expandable adhesive, and the thermally expandable adhesive is an adhesive whose adhesive strength is reduced or lost when heated at a temperature exceeding 150°C.

16. The method for manufacturing an electronic device according to any one of claims 1 to 15, wherein the sealing material includes an epoxy resin-based sealing material.

17. The method for manufacturing an electronic device according to any one of claims 1 to 16, wherein the electronic device comprises a fan-out type package.

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