Manufacturing methods of electronic devices

Abstract

A method for manufacturing an electronic device includes at least the following steps: a preparation step of preparing a structure (100) having an adhesive film (50), an electronic component (70), and a support substrate (80); a pre-baking step of heating the structure (100); and a sealing step of sealing the electronic component (70) with a sealing material (60). The adhesive film (50) includes: a substrate layer (10); an adhesive resin layer (A) disposed on a first surface (10A) side of the substrate layer (10) for temporarily fixing the electronic component (70); and an adhesive resin layer (B) disposed on a second surface (10B) side of the substrate layer (10) whose adhesive strength is reduced by external stimulation. The electronic component (70) is bonded to the adhesive resin layer (A) of the adhesive film (50), and the support substrate (80) is bonded to the adhesive resin layer (B) of the adhesive film (50).

Description

Technical Field

[0001] This invention relates to a method for manufacturing an electronic device. Background Technology

[0002] Fan-out WLP (wafer-level packaging) has been developed as a technology that enables the miniaturization and weight reduction of electronic devices (e.g., semiconductor devices).

[0003] In eWLB (Embedded Wafer Level Ball Grid Array), one of the fabrication methods for fan-out type WLP, the following method is used: multiple electronic components, such as semiconductor chips, are temporarily fixed separately on an adhesive film attached to a support substrate, and then the multiple electronic components are sealed together using a sealing material. Here, the adhesive film needs to be adhered to the electronic components and the support substrate during the sealing process, and after sealing, it needs to be removed from the sealed electronic components together with the support substrate.

[0004] As for the technology related to the manufacturing method of such a fan-out type WLP, for example, the technology described in Patent Document 1 (Japanese Patent Application Publication No. 2011-134811) can be cited.

[0005] Patent Document 1 discloses a heat-resistant adhesive sheet for manufacturing semiconductor devices, characterized in that: it is used to bond a substrate-free semiconductor chip during resin sealing. The heat-resistant adhesive sheet has a substrate layer and an adhesive layer. The adhesive layer is such that the adhesion force to SUS304 after bonding is 0.5N / 20mm or more, and it is cured by stimulation until the end of the resin sealing process, thereby achieving a peel force of 2.0N / 20mm or less for the package.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2011-134811 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] According to the research of the inventors, when electronic components are disposed on an adhesive film and sealed with a sealing material, the position of the electronic components may sometimes shift (hereinafter also referred to as electronic component position shift).

[0011] The present invention is made in view of the above circumstances and provides a method for manufacturing an electronic device capable of suppressing positional displacement of electronic components during the sealing process.

[0012] Solution for solving the problem

[0013] The inventors conducted repeated and in-depth research to solve the aforementioned problems. As a result, they discovered that by performing a pre-baking process before the sealing process, it is possible to suppress the positional shift of electronic components during the sealing process, thereby completing this invention.

[0014] According to the present invention, a method for manufacturing the electronic device shown below is provided. [1]

[0016] A method for manufacturing an electronic device, comprising at least the following steps:

[0017] Preparation process for a structure containing an adhesive film, electronic components, and a supporting substrate;

[0018] A pre-baking process involving heating the aforementioned structure; and

[0019] The sealing process involves sealing the aforementioned electronic components using a sealing material.

[0020] The adhesive film comprises: a substrate layer; an adhesive resin layer (A) disposed on a first side of the substrate layer for temporarily fixing electronic components; and an adhesive resin layer (B) disposed on a second side of the substrate layer whose adhesive strength is reduced by external stimulation.

[0021] The electronic component is bonded to the adhesive resin layer (A) of the adhesive film.

[0022] The supporting substrate is bonded to the adhesive resin layer (B) of the adhesive film. [2]

[0024] According to the manufacturing method of the electronic device described above [1], the heating temperature in the pre-baking process is less than 160°C. [3]

[0026] According to the manufacturing method of the electronic device described in [1] or [2] above, the heating temperature in the pre-baking process is 70°C or higher. [4]

[0028] According to the manufacturing method of the electronic device according to any one of [1] to [3] above, after the sealing process, it further includes a first peeling process: by applying external stimulation to reduce the adhesion of the adhesive resin layer (B) to peel the support substrate from the structure. [5]

[0030] According to the manufacturing method of the electronic device described above [4], after the first peeling step, it further includes a second peeling step: peeling the adhesive film from the electronic component. [6]

[0032] According to the manufacturing method of the electronic device according to any one of [1] to [5] above, the sealing material is an epoxy resin-based sealing material. [7]

[0034] According to the manufacturing method of the electronic device according to any one of [1] to [6] above, the adhesive resin constituting the adhesive resin layer (A) includes one or more selected from (meth)acrylic adhesive resin, silicone adhesive resin, urethane adhesive resin, olefin adhesive resin and styrene adhesive resin.

[0035] The effects of the invention

[0036] According to the present invention, a method for manufacturing an electronic device is provided that can suppress positional displacement of electronic components during the sealing process. Attached Figure Description

[0037] Figure 1 A cross-sectional view illustrating an example of the structure of an adhesive film according to an embodiment of the present invention.

[0038] Figure 2 A cross-sectional view illustrating an example of a method for manufacturing an electronic device according to an embodiment of the present invention.

[0039] Figure 3 A cross-sectional view illustrating an example of a method for manufacturing an electronic device according to an embodiment of the present invention. Detailed Implementation

[0040] Hereinafter, embodiments of the present invention will be described using the accompanying drawings. Furthermore, in all the drawings, common symbols are used for the same constituent elements, and descriptions are appropriately omitted. Also, the figures are schematic diagrams and do not conform to actual size ratios. Furthermore, unless otherwise specified, the numerical range "A to B" indicates A or more and B or less. In this embodiment, "(meth)acrylic acid" refers to acrylic acid, methacrylic acid, or both acrylic acid and methacrylic acid.

[0041] 1. Manufacturing method of electronic devices

[0042] First, the method for manufacturing the electronic device involved in this embodiment will be described. Figure 1 A cross-sectional view illustrating an example of the structure of the adhesive film 50 according to an embodiment of the present invention.

[0043] Figure 2 and Figure 3 A cross-sectional view illustrating an example of a method for manufacturing an electronic device according to an embodiment of the present invention.

[0044] The manufacturing method of the electronic device involved in this embodiment includes at least the following three steps.

[0045] (1) Preparation step: Prepare a structure 100 having an adhesive film 50, an electronic component 70, and a support substrate 80. The adhesive film 50 includes: a substrate layer 10; an adhesive resin layer (A) disposed on a first surface 10A of the substrate layer 10 for temporarily fixing the electronic component 70; and an adhesive resin layer (B) disposed on a second surface 10B of the substrate layer 10, whose adhesive strength is reduced by external stimulation. The electronic component 70 is bonded to the adhesive resin layer (A) of the adhesive film 50, and the support substrate 80 is bonded to the adhesive resin layer (B) of the adhesive film 50.

[0046] (2) Pre-baking process: heating the structure 100.

[0047] (3) Sealing process: The electronic component 70 is sealed by sealing material 60.

[0048] As described above, according to the research of the inventors, when electronic components are disposed on an adhesive film and sealed with a sealing material, the position of the electronic components may sometimes shift (hereinafter also referred to as electronic component position shift).

[0049] The inventors conducted repeated and in-depth research to solve the aforementioned problems. As a result, they realized that during the sealing process of electronic components, the pressure caused by the flow of the sealing material cannot be fully withstood, leading to positional displacement of the electronic components. Furthermore, they realized that positional displacement of the electronic components also occurs due to the release of moisture contained in the adhesive film, particularly from the release of moisture contained in the adhesive resin layer adhered to the support substrate side.

[0050] Based on the above understanding, the inventors conducted further repeated research. As a result, they discovered for the first time that by performing a pre-baking process of heating the structure 100 before the sealing process, the adhesion of the adhesive resin layer (A) to the electronic component 70 is improved, thereby suppressing the positional displacement of the electronic component during the sealing process.

[0051] That is, according to the manufacturing method of the electronic device according to this embodiment, since a pre-baking process of heating the structure 100 is performed before the sealing process, the adhesion of the adhesive resin layer (A) to the electronic component 70 is improved. Therefore, it is possible to suppress the displacement of the electronic component 70 due to the pressure caused by the flow of the sealing material 60 or the release of moisture during the sealing process.

[0052] As described above, the manufacturing method of the electronic device according to this embodiment can suppress the positional displacement of electronic components during the sealing process.

[0053] The following describes each step of the manufacturing method of the electronic device according to this embodiment.

[0054] (1) Preparation process)

[0055] In the preparation process, a structure 100 is prepared, which includes an adhesive film 50, an electronic component 70 bonded to an adhesive resin layer (A) of the adhesive film 50, and a support substrate 80 bonded to an adhesive resin layer (B) of the adhesive film 50.

[0056] Such a structure 100, for example, can be made using the following steps.

[0057] First, an adhesive film 50 is attached to the support substrate 80 such that the adhesive resin layer (B) is on the side of the support substrate 80. A protective film, called a spacer, may also be attached to the adhesive resin layer (B), and the protective film can be peeled off to attach the exposed side of the adhesive resin layer (B) to the surface of the support substrate 80.

[0058] As the support substrate 80, materials such as quartz substrate, glass substrate, and SUS substrate can be used.

[0059] Next, by placing the electronic components 70 on the adhesive resin layer (A) of the adhesive film 50 attached to the support substrate 80, the structure 100 can be obtained.

[0060] Examples of electronic components 70 include, for example, ICs, LSIs, discrete components, light-emitting diodes, light-receiving elements, semiconductor chips, semiconductor panels, semiconductor packages, etc.

[0061] (2) Pre-baking process)

[0062] In the pre-baking process, the structure 100 obtained in the preparation process is heated. This operation improves the adhesion of the adhesive resin layer (A) to the electronic component 70 within the adhesive film 50. As a result, during the sealing process, when the electronic component 70 is sealed with the sealing material 60, it is possible to suppress any displacement of the electronic component 70 caused by pressure from the flow of the sealing material 60 or by the release of moisture.

[0063] In the pre-baking process, the upper limit of the temperature at which the structure 100 is heated is not particularly limited as long as it is a temperature that can increase the adhesion of the adhesive resin layer (A) to the electronic component 70. Preferably, it is less than 160°C, more preferably less than 155°C, and even more preferably less than 150°C. This suppresses the rapid generation of gas release from the moisture contained in the adhesive film, and as a result, it further suppresses the positional displacement of the electronic component 70 due to gas release from moisture in the pre-baking and sealing processes. Furthermore, if the adhesive resin layer (B) is of the heat-expanding type, if the temperature at which the structure 100 is heated is less than or below the aforementioned upper limit, thermal expansion is suppressed. Therefore, the decrease in the adhesion of the adhesive film 50 to the support substrate 80 is suppressed, and as a result, it suppresses the peeling of the adhesive film 50 from the support substrate 80 during the sealing process of the electronic component.

[0064] In the pre-baking process, the lower limit temperature for heating the structure 100 is not particularly limited as long as it can increase the adhesion of the adhesive resin layer (A) to the electronic component 70. Preferably, it is 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. This shortens the heating time in the pre-baking process, resulting in a shorter manufacturing time for the electronic device. Shortening the manufacturing time of the electronic device improves its productivity.

[0065] The heating time of the structure 100 is not particularly limited as long as it is a heating time that can improve the adhesion of the adhesive resin layer (A) to the electronic component 70. For example, it is in the range of 1 minute to 120 minutes, preferably 5 minutes to 80 minutes.

[0066] There are no particular limitations on the method of heating the structure 100. For example, commonly known heat treatment methods such as ovens, dryers, heating rollers, and drying furnaces can be used.

[0067] Whether the adhesion of the adhesive resin layer (A) to the electronic component 70 is improved can be determined, for example, by using known methods such as the Shore share strength between the electronic component 70 and the adhesive film 50.

[0068] (3) Sealing process)

[0069] Next, the electronic component 70 is sealed with sealing material 60.

[0070] The electronic component 70 is covered by a sealing material 60, for example, by curing the sealing material 60 at a temperature below 150°C, thereby sealing the electronic component 70.

[0071] Furthermore, the form of the sealing material 60 is not particularly limited; for example, it can be granular, flake-like, or liquid.

[0072] As for the sealing material 60, there are no particular limitations; for example, an epoxy resin-based sealing material using epoxy resin can be used.

[0073] Considering that the sealant 60 has better affinity for the adhesive film 50 and can seal the electronic component 70 more uniformly, a liquid epoxy resin-based sealant is particularly preferred.

[0074] As such epoxy resin-based sealants, products such as the T693 / R4000 series, T693 / R1000 series, and T693 / R5000 series manufactured by Nagase ChemteX can be used.

[0075] Examples of sealing methods include transfer molding, injection molding, compression molding, and casting. After sealing the electronic component 70 with the sealing material 60, the sealing material 60 can be cured, for example, by heating at a temperature below 150°C, to obtain a structure 100 in which the electronic component 70 is sealed.

[0076] ((4) First stripping process)

[0077] In the manufacturing method of the electronic device according to this embodiment, it is also possible to use the following method: Figure 3 As shown, after the sealing process (3), a first peeling process is further performed: by applying external stimulation, the adhesive force of the adhesive resin layer (B) is reduced so as to peel the support substrate 80 from the structure 100.

[0078] For example, after sealing the electronic component 70, the support substrate 80 can be heated to a temperature exceeding 150°C to reduce the adhesive force of the adhesive resin layer (B), thereby making it easy to remove from the adhesive film 50.

[0079] (5) Second stripping process)

[0080] In the manufacturing method of the electronic device according to this embodiment, it is also possible to use the following method: Figure 3As shown, after the first peeling process, a second peeling process is further performed: the adhesive film 50 is peeled off from the electronic component 70 to obtain the electronic device 200.

[0081] Examples of methods for peeling the adhesive film 50 from the electronic component 70 include, for example, mechanical peeling or peeling after reducing the adhesive force on the surface of the adhesive film 50.

[0082] (Other processes)

[0083] In the manufacturing method of the electronic device according to this embodiment, it is also possible to use the following method: Figure 3 As shown, the process further includes step (6): forming a wiring layer 310 and a bump 320 on the exposed surface of the obtained electronic device 200 to obtain the electronic device 300.

[0084] The wiring layer 310 includes: a pad (not shown) formed on the outermost surface as an external connection terminal, and wiring (not shown) that electrically connects the exposed electronic component 70 to the pad. The wiring layer 310 can be formed by conventionally known methods and can be a multilayer structure.

[0085] Furthermore, bumps 320 can be formed on the pads of the wiring layer 310 to obtain the electronic device 300. Examples of bumps 320 include solder bumps and gold bumps. For example, solder bumps can be formed by placing solder balls on the pads that serve as external connection terminals of the wiring layer 310 and melting (reflowing) the solder by heating. Gold bumps can be formed using methods such as ball bonding, plating, and Au ball transfer.

[0086] Furthermore, in the manufacturing method of the electronic device according to this embodiment, it is possible to... Figure 3 As shown, the next step (7) is to cut the electronic device 300 to obtain multiple electronic devices 400.

[0087] The cutting of the electronic device 300 can be performed using known methods.

[0088] 2. Adhesive film

[0089] The adhesive film 50 described below is an example of this embodiment.

[0090] Figure 1 A cross-sectional view illustrating an example of the structure of the adhesive film 50 according to an embodiment of the present invention.

[0091] like Figure 1As shown, the adhesive film 50 according to this embodiment includes: a substrate layer 10; an adhesive resin layer (A) disposed on the first surface 10A side of the substrate layer 10; and an adhesive resin layer (B) disposed on the second surface 10B side of the substrate layer 10, whose adhesive force is reduced by external stimulation.

[0092] Regarding the overall thickness of the adhesive film 50 involved in this embodiment, from the viewpoint of balancing mechanical properties and operability, it is preferably 10 μm or more and 1000 μm or less, and more preferably 20 μm or more and 500 μm or less.

[0093] Next, the layers constituting the adhesive film 50 according to this embodiment will be described.

[0094] <Substrate Layer>

[0095] The substrate layer 10 is a layer provided for the purpose of improving the operability, mechanical properties, heat resistance and other properties of the adhesive film 50.

[0096] The substrate layer 10 is not particularly limited, but can be exemplified by, for example, a resin film.

[0097] As the resin constituting the above-mentioned resin film, a known thermoplastic resin can be used. Examples include, for instance, polyolefins selected from polyethylene, polypropylene, poly(4-methyl-1-pentene), poly(1-butene), etc.; polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.; polyamides such as nylon-6, nylon-66, poly(m-phenylene adipamide); polyacrylates; polymethacrylates; polyvinyl chloride; polyvinylidene chloride; polyimide; polyetherimide; ethylene-vinyl acetate copolymer; polyacrylonitrile; polycarbonate; polystyrene; ion-crosslinked polymers; polysulfone; polyethersulfone; polyphenylene ether, etc., one or more of the following.

[0098] Among these, from the viewpoint of achieving an excellent balance of transparency, mechanical strength, price, etc., it is preferable to select one or more of polypropylene, polyethylene terephthalate, polyethylene naphthalate, polyamide, and polyimide, and more preferably to select at least one of polyethylene terephthalate and polyethylene naphthalate.

[0099] The substrate layer 10 can be a single layer or two or more layers.

[0100] Furthermore, the resin film used to form the substrate layer 10 can be a stretched film, or a film stretched in a uniaxial or biaxial direction. From the viewpoint of improving the mechanical strength of the substrate layer 10, a film stretched in a uniaxial or biaxial direction is preferred.

[0101] 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.

[0102] To improve adhesion to other layers, the substrate layer 10 may undergo surface treatment. Specifically, it may undergo corona treatment, plasma treatment, undercoat treatment, prime coat treatment, etc.

[0103] <Adhesive resin layer (A)>

[0104] The adhesive resin layer (A) is a layer disposed on one side of the substrate layer 10. For example, it is a layer used to contact the surface of the electronic component and temporarily fix the electronic component when sealing the electronic component with a sealing material during the manufacturing process of the electronic device.

[0105] The adhesive resin layer (A) comprises an adhesive resin (A1).

[0106] Examples of adhesive resins (A1) include (meth)acrylic adhesive resins (a), silicone adhesive resins, urethane adhesive resins, olefin adhesive resins, and styrene adhesive resins.

[0107] Among these, from the viewpoint of making it easier to adjust the adhesion, (meth)acrylic adhesive resin (a) is preferred.

[0108] As the adhesive resin layer (A), a radiation-crosslinked adhesive resin layer whose adhesive strength is reduced by radiation can also be used. The radiation-crosslinked adhesive resin layer is crosslinked by radiation, significantly reducing adhesive strength, thus making it easy to peel the adhesive film 50 from the electronic component. Examples of radiation include ultraviolet rays, electron beams, and infrared rays.

[0109] As a radiation-crosslinked adhesive resin layer, an ultraviolet-crosslinked adhesive resin layer is preferred.

[0110] Examples of (meth)acrylic adhesive resins (a) used as adhesive resin layers (A) include, for example, copolymers comprising alkyl methacrylate monomer units (a1) and monomer units (a2) having functional groups capable of reacting with crosslinking agents.

[0111] In this embodiment, the term (meth)acrylate refers to alkyl acrylate, alkyl methacrylate, or a mixture thereof.

[0112] The (meth)acrylic adhesive resin (a) involved in this embodiment can be obtained, for example, by copolymerizing a monomer mixture containing an alkyl methacrylate monomer (a1) and a monomer (a2) having a functional group capable of reacting with a crosslinking agent.

[0113] Examples of monomers (a1) forming the alkyl (meth)acrylate monomer unit (a1) include alkyl (meth)acrylates having an alkyl group having about 1 to 12 carbon atoms. Alkyl (meth)acrylates having an alkyl group having 1 to 8 carbon atoms are preferred. Specifically, examples include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, and 2-ethylhexyl methacrylate. These can be used alone or in combination.

[0114] In the (meth)acrylic adhesive resin (a) according to this embodiment, when the total of all monomer units in the (meth)acrylic adhesive resin (a) is set to 100% by mass, the content of (meth)acrylic 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.

[0115] Examples of monomers (a2) that form monomer units (a2) having functional groups capable of reacting with crosslinking agents include acrylic acid, methacrylic acid, itaconic acid, mesaconic acid, citraconic acid, fumaric acid, maleic acid, monoalkyl itaconic acid esters, monoalkyl mesaconic acid esters, monoalkyl citraconic acid esters, monoalkyl fumaric acid esters, monoalkyl maleic acid esters, glycidyl acrylate, glycidyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide, methacrylamide, tert-butylaminoethyl acrylate, and tert-butylaminoethyl methacrylate. Preferred monomers include acrylic acid, methacrylic acid, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide, and methacrylamide. These can be used alone or in combination.

[0116] In the (meth)acrylic adhesive resin (a) according to this embodiment, when the total of all monomer units in the (meth)acrylic adhesive resin (a) is set to 100% by mass, the content of 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.

[0117] In the (meth)acrylic adhesive resin (a) involved in this embodiment, in addition to monomer units (a1) and monomer units (a2), it may further include two functional monomer units (a3) ​​and a specific comonomer unit (hereinafter referred to as a polymerizable surfactant) unit having the properties of a surfactant.

[0118] Polymerizable surfactants have the property of copolymerizing with monomers (a1), (a2), and (a3), and in the case of emulsion polymerization, they act as emulsifiers.

[0119] Examples of monomers (a3) ​​that form the difunctional monomer unit (a3) ​​include allyl methacrylate, allyl acrylate, divinylbenzene, vinyl methacrylate, vinyl acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tetraethylene glycol di(meth)acrylate, and for example, those with diacrylate or dimethacrylate ends and a propylene glycol-type main chain structure (e.g., Nippon Oils & Fats Co., Ltd.). Substances with trade names such as PDP-200, Nippon Yushi Co., Ltd.'s PDP-400, Nippon Yushi Co., Ltd.'s ADP-200, Nippon Yushi Co., Ltd.'s ADP-400, 1,4-butanediol type (e.g., Nippon Yushi Co., Ltd.'s trade name: ADT-250, Nippon Yushi Co., Ltd.'s ADT-850) and their mixtures (e.g., Nippon Yushi Co., Ltd.'s trade name: ADET-1800, Nippon Yushi Co., Ltd.'s ADPT-4000).

[0120] In the (meth)acrylic adhesive resin (a) according to this embodiment, when the total of all monomer units in the (meth)acrylic adhesive resin (a) is set to 100% by mass, the content of monomer unit (a3) ​​is preferably 0.1% by mass or more than 30% by mass, more preferably 0.1% by mass or more than 15% by mass, even more preferably 0.1% by mass or more than 20% by mass, and particularly preferably 0.1% by mass or more than 5% by mass.

[0121] Examples of polymerizable surfactants include surfactants with polymerizable 1-propenyl groups introduced into the benzene ring of polyoxyethylene nonylphenyl ether (manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.; trade names: Akuro RN-10, Akuro RN-20, Akuro RN-30, Akuro RN-50, etc.), surfactants with polymerizable 1-propenyl groups introduced into the benzene ring of the ammonium salt of polyoxyethylene nonylphenyl ether sulfate (manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.; trade names: Akuro HS-10, Akuro HS-20, Akuro HS-1025, etc.), and sulfosuccinate diesters with polymerizable double bonds within the molecule (manufactured by Kao Corporation; trade names: Laterumul S-120A, Laterumul S-180A, etc.).

[0122] In the (meth)acrylic adhesive resin (a) according to this embodiment, when the total of all monomer units in the (meth)acrylic adhesive resin (a) is set to 100% by mass, the content of the polymerizable surfactant is preferably 0.1% by mass or more than 30% by mass, more preferably 0.1% by mass or more than 15% by mass, even more preferably 0.1% by mass or more than 20% by mass, and particularly preferably 0.1% by mass or more than 5% by mass.

[0123] The (meth)acrylic adhesive resin (a) involved in this embodiment may further contain monomer units formed by monomers with polymerizable double bonds, such as vinyl acetate, acrylonitrile, and styrene, as needed.

[0124] Examples of polymerization mechanisms for the (meth)acrylic adhesive resin (a) described in this embodiment include free radical polymerization, anionic polymerization, and cationic polymerization. Considering factors such as the manufacturing cost of the (meth)acrylic adhesive resin (a), the influence of the functional groups of the monomers, and the influence of ions on the surface of electronic components, free radical polymerization is preferred.

[0125] When polymerization is carried out via free radical polymerization, examples of free radical polymerization initiators include organic peroxides such as benzoyl peroxide, di-tert-butyl peroxide, dicumyl peroxide, 3,3,5-trimethylhexanoyl peroxide, di-2-ethylhexyl peroxide, methyl ethyl ketone peroxide, tert-butyl peroxide, tert-butyl peroxide, di-tert-butyl peracetate, tert-butyl peroxide, tert-butyl peroxide-2-hexanoate, tert-butyl peroxide-2-ethylhexanoate, tert-butyl peroxide-3,5,5-trimethylhexanoate, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, tert-butyl peroxide, and di-tert-pentyl 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-cyanopentanoic acid.

[0126] When polymerization is carried out via emulsion polymerization, water-soluble inorganic peroxides such as ammonium persulfate, potassium persulfate, and sodium persulfate are preferred among these free radical polymerization initiators, as are water-soluble azo compounds containing carboxyl groups, such as 4,4'-azobis-4-cyanopentanoic acid. Considering the influence of ions on the surface of electronic components, azo compounds containing carboxyl groups, such as ammonium persulfate and 4,4'-azobis-4-cyanopentanoic acid, are further preferred, and particularly preferred are azo compounds containing carboxyl groups, such as 4,4'-azobis-4-cyanopentanoic acid.

[0127] In the adhesive resin layer (A) of this embodiment, in addition to the adhesive resin (A1), it is preferable to further include a crosslinking agent (A2) having two or more crosslinking functional groups in one molecule.

[0128] A crosslinking agent (A2) with two or more crosslinking functional groups in one molecule is used to react with the functional groups of the adhesive resin (A1) to adjust the adhesion and cohesion.

[0129] 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, trimethylolpropane toluene diisocyanate triadduct, polyisocyanates, diphenylmethane diisocyanate, and toluene diisocyanate; and trimethylolpropane-tri-β-aziridinylpropionate, tetramethylolpropane-tri-β-aziridinylpropionate, etc. Aziridine compounds such as β-aziridine propionate, 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-phenylenediamine and 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane; and melamine compounds such as hexamethoxyhydroxymethyl melamine. These can be used alone or in combination of two or more.

[0130] These preferably include one or more compounds selected from epoxy compounds, isocyanate compounds, and aziridine compounds.

[0131] The content of the crosslinking agent (A2) is generally preferably within the range where the number of functional groups in the crosslinking agent (A2) does not exceed the number of functional groups in the adhesive resin (A1). However, in cases where new functional groups are generated through the crosslinking reaction, or where the crosslinking reaction is slow, it may be contained in excess as needed.

[0132] Regarding the content of crosslinking agent (A2) in the adhesive resin layer (A), from the viewpoint of improving the heat resistance of the adhesive resin layer (A) and balancing the adhesion, it is preferably 0.1 parts by mass or more and 15 parts by mass or less relative to 100 parts by mass of adhesive resin (A1).

[0133] The adhesive resin layer (A) may include additives such as plasticizers and tackifying resins as other components. When the adhesive resin layer (A) is a radiation-crosslinked adhesive resin layer, it may contain various additives for radiation crosslinking. When the total content of the adhesive resin layer (A) is set to 100% by mass, the combined content of the adhesive resin (A1) and crosslinking agent (A2) in the adhesive resin layer (A) is preferably 50% by mass or more, more preferably 70% by mass or more, further preferably 90% by mass or more, and particularly preferably 95% by mass or more. This further suppresses residual adhesive on the electronic component side when peeling the adhesive film from the electronic component.

[0134] The thickness of the adhesive resin layer (A) is not particularly limited, but is preferably 1 μm or more and 100 μm or less, and more preferably 3 μm or more and 50 μm or less.

[0135] The adhesive resin layer (A) can be formed, for example, by applying an adhesive to the substrate layer 10. The adhesive can be dissolved in a solvent and applied as a coating liquid, applied as an aqueous emulsion, or applied directly as a liquid adhesive.

[0136] Preferably, the adhesive coating solution is soluble in an organic solvent. The organic solvent is not particularly limited; it can be appropriately selected from known organic solvents based on solubility and drying time. Examples of organic solvents include ester-based solvents such as ethyl acetate and methyl acetate; ketone-based solvents such as acetone and MEK; aromatic solvents such as benzene, toluene, and ethylbenzene; straight-chain or cyclic aliphatic solvents such as heptane, hexane, and cyclohexane; and alcohol-based solvents such as isopropanol and butanol. Ethyl acetate and toluene are preferred organic solvents. One of these solvents can be used alone, or two or more can be mixed.

[0137] As a method for applying the adhesive coating liquid, conventionally known coating methods can be used, such as roller coating, reverse roller coating, gravure roller coating, bar coating, corner wheel coating, and die coating. There are no particular limitations on the drying conditions of the coated adhesive; generally, drying at a temperature range of 80–200°C for 10 seconds to 10 minutes is preferred. Drying at 80–170°C for 15 seconds to 5 minutes is even more preferred. To fully promote the crosslinking reaction between the crosslinking agent and the adhesive, the adhesive coating liquid can be heated at 40–80°C for approximately 5–300 hours after drying.

[0138] Furthermore, the substrate layer 10 and the adhesive resin layer (A) can be formed by co-extrusion molding, or by laminating (delaminating) the film-like substrate layer 10 and the film-like adhesive resin layer (A).

[0139] <Adhesive resin layer (B)>

[0140] The adhesive film 50 of this embodiment has an adhesive resin layer (B) on the second surface 10B side of the substrate layer 10 opposite to the first surface 10A, which has reduced adhesion due to external stimulation.

[0141] Therefore, by applying external stimulation, the adhesive film 50 can be easily peeled off from the support substrate 80.

[0142] Here, examples of adhesive resin layers (B) whose adhesive strength decreases due to external stimuli include, for instance, heat-release type adhesive resin layers whose adhesive strength decreases due to heating, and radiation-release type adhesive resin layers whose adhesive strength decreases due to radiation. Among these, heat-release type adhesive resin layers whose adhesive strength decreases due to heating are preferred.

[0143] Examples of heat-expandable adhesive resin layers include, for example, adhesive resin layers composed of heat-expandable adhesives containing gas-generating components, heat-expandable adhesives containing heat-expandable microspheres that expand to reduce adhesion, and heat-expandable adhesives whose adhesion is reduced by the cross-linking reaction of adhesive components due to heat.

[0144] In this embodiment, the heat-expanding adhesive used for the adhesive resin layer (B) is, for example, an adhesive whose adhesive strength decreases or is lost when heated to a temperature exceeding 150°C. For example, a material that does not peel off below 150°C but peels off at temperatures exceeding 150°C can be selected, preferably having an adhesive strength sufficient to prevent the adhesive film 50 from peeling off from the support substrate 80 during the manufacturing process of the electronic device.

[0145] Here, for cases where adhesive strength decreases or is lost due to heating at temperatures exceeding 150°C, an evaluation can be conducted, for example, as follows: The adhesive resin layer (B) is adhered to a stainless steel sheet, heated at 140°C for 1 hour, and then heated at temperatures exceeding 150°C for 2 minutes. The peel strength from the stainless steel sheet is then measured, and the evaluation is based on this peel strength. The specific heating temperature exceeding 150°C can be set to a temperature higher than the temperature at which the gas is generated or the temperature at which the thermally expandable microspheres expand. This temperature can be appropriately set depending on the type of gas generated and the type of thermally expandable microspheres. In this embodiment, "loss of adhesive strength" refers to, for example, a 180° peel strength measured at 23°C and a tensile speed of 300 mm / min that is less than 0.5 N / 25 mm.

[0146] As a gas-generating component used in heat-expanding adhesives, compounds such as azo compounds, azido compounds, and McFarland acid derivatives can be used. In addition, inorganic foaming agents such as ammonium carbonate, ammonium bicarbonate, sodium bicarbonate, ammonium nitrite, sodium borohydride, and various azide compounds, as well as water, can also be used; chlorofluorocarbon compounds such as trichloromonofluoromethane and dichloromonofluoromethane; azo compounds such as azobisisobutyronitrile, azodicarbonamide, and barium azodicarbonate; hydrazine compounds such as p-toluenesulfonyl hydrazine, diphenyl sulfonyl hydrazine, 4,4'-oxybis(benzenesulfonyl hydrazine), and allyl bis(sulfonyl hydrazine); aminourea compounds such as p-methylphenylenesulfonamide and 4,4'-oxybis(benzenesulfonamide); triazole compounds such as 5-morpholino-1,2,3,4-thiatriazole; and organic foaming agents such as N,N'-dinitrospentamethylenetetramine and N,N'-dimethyl-N,N'-dinitrosterephthalamide. The gas-generating components can be added to the adhesive resin (B1) or directly bonded to the adhesive resin (B1).

[0147] Thermally expandable microspheres used as heat-expanding adhesives can utilize, for example, microencapsulated foaming agents. Examples of such thermally expandable microspheres include microspheres containing substances such as isobutane, propane, and pentane that readily vaporize and expand upon heating, encapsulated within an elastic shell. Examples of materials constituting the shell include, for example, 1,1-dichloroethylene-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, and polysulfone. Thermally expandable microspheres can be manufactured, for example, by methods such as coagulation or interfacial polymerization.

[0148] Thermally expandable microspheres can be added to adhesive resins.

[0149] The content of at least one of the gas-generating components and thermally expandable microspheres can be appropriately set according to the expansion ratio of the heat-peelable adhesive resin layer (B), the reduction of adhesive force, etc., and is not particularly limited. For example, it is 1 part or more to 150 parts or less of adhesive resin (B1) in the heat-peelable adhesive resin layer (B) relative to 100 parts by mass, preferably 10 parts or more to 130 parts or less of adhesive resin (B1), and more preferably 12 parts or more to 100 parts or less of adhesive resin (B1).

[0150] The temperature at which the gas is generated and the temperature at which the thermally expandable microspheres expand are preferably designed to exceed 150°C.

[0151] Examples of adhesive resins (B1) constituting heat-expanding adhesives include (meth)acrylic resins (b), urethane resins, silicone resins, polyolefin resins, polyester resins, polyamide resins, fluorinated resins, and styrene-diene block copolymer resins. Among these, (meth)acrylic resin (b) is preferred.

[0152] Examples of (meth)acrylic adhesive resins (b) used as adhesive resin layers (B) include, for example, copolymers comprising alkyl methacrylate monomer units (b1) and monomer units (b2) having functional groups capable of reacting with crosslinking agents.

[0153] In this embodiment, the term (meth)acrylate refers to alkyl acrylate, alkyl methacrylate, or a mixture thereof.

[0154] The (meth)acrylic adhesive resin (b) involved in this embodiment can be obtained, for example, by copolymerizing a monomer mixture containing an alkyl (meth)acrylic ester monomer (b1) and a monomer (b2) having a functional group capable of reacting with a crosslinking agent.

[0155] As the monomer (b1) forming the alkyl (meth)acrylate monomer unit (b1), examples of alkyl (meth)acrylates having an alkyl group having about 1 to 12 carbon atoms are possible. Alkyl (meth)acrylates having an alkyl group having 1 to 8 carbon atoms are preferred. Specifically, examples include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, and 2-ethylhexyl methacrylate. These can be used alone or in combination.

[0156] In the (meth)acrylic adhesive resin (b) according to this embodiment, when the total of all monomer units in the (meth)acrylic adhesive resin (b) is set to 100% by mass, the content of (meth)acrylic 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.

[0157] Examples of monomers (b2) that form monomer units (b2) having functional groups capable of reacting with crosslinking agents include acrylic acid, methacrylic acid, itaconic acid, mesaconic acid, citraconic acid, fumaric acid, maleic acid, monoalkyl itaconic acid esters, monoalkyl mesaconic acid esters, monoalkyl citraconic acid esters, monoalkyl fumaric acid esters, monoalkyl maleic acid esters, glycidyl acrylate, glycidyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide, methacrylamide, tert-butylaminoethyl acrylate, and tert-butylaminoethyl methacrylate. Preferred monomers include acrylic acid, methacrylic acid, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide, and methacrylamide. These can be used alone or in combination.

[0158] In the (meth)acrylic adhesive resin (b) of this embodiment, when the total of all monomer units in the (meth)acrylic adhesive resin (b) is set to 100% by mass, the content of 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.

[0159] In the (meth)acrylic adhesive resin (b) of this embodiment, in addition to monomer units (b1) and monomer units (b2), it may further include two functional monomer units (b3) and a specific comonomer (hereinafter referred to as a polymerizable surfactant) unit having the properties of a surfactant.

[0160] Polymerizable surfactants have the property of copolymerizing with monomers (b1), (b2) and (b3), and in the case of emulsion polymerization, they act as emulsifiers.

[0161] Examples of monomers (b3) forming the difunctional monomer unit (b3) include allyl methacrylate, allyl acrylate, divinylbenzene, vinyl methacrylate, vinyl acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tetraethylene glycol di(meth)acrylate, and for example, those with diacrylate or dimethacrylate ends and a propylene glycol-type main chain structure (e.g., Nippon Oils & Fats Co., Ltd.). Monomers of the following trade names: PDP-200, Nippon Yushi Co., Ltd.'s PDP-400, Nippon Yushi Co., Ltd.'s ADP-200, Nippon Yushi Co., Ltd.'s ADP-400, 1,4-butanediol type (e.g., Nippon Yushi Co., Ltd.'s trade name: ADT-250, Nippon Yushi Co., Ltd.'s ADT-850) and their mixtures (e.g., Nippon Yushi Co., Ltd.'s trade name: ADET-1800, Nippon Yushi Co., Ltd.'s ADPT-4000).

[0162] In the (meth)acrylic adhesive resin (b) according to this embodiment, when the total of all monomer units in the (meth)acrylic adhesive resin (b) is set to 100% by mass, the content of monomer unit (b3) is preferably 0.1% by mass or more than 30% by mass, more preferably 0.1% by mass or more than 15% by mass, even more preferably 0.1% by mass or more than 20% by mass, and particularly preferably 0.1% by mass or more than 5% by mass.

[0163] Examples of polymerizable surfactants include surfactants with a polymerizable 1-propenyl group introduced into the benzene ring of polyoxyethylene nonylphenyl ether (manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.; trade names: Acron RN-10, Acron RN-20, Acron RN-30, Acron RN-50, etc.), surfactants with a polymerizable 1-propenyl group introduced into the benzene ring of the ammonium salt of polyoxyethylene nonylphenyl ether sulfate (manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.; trade names: Acron HS-10, Acron HS-20, Acron HS-1025, etc.), and sulfosuccinate diesters with polymerizable double bonds within the molecule (manufactured by Kao Corporation; trade names: Laterumul S-120A, Laterumul S-180A, etc.).

[0164] In the (meth)acrylic adhesive resin (b) according to this embodiment, when the total of all monomer units in the (meth)acrylic adhesive resin (b) is set to 100% by mass, the content of the polymerizable surfactant is preferably 0.1% by mass or more and 30% by mass or less, more preferably 0.1% by mass or more and 15% by mass or less, 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.

[0165] The (meth)acrylic adhesive resin (b) involved in this embodiment may further contain monomer units formed by monomers with polymerizable double bonds, such as vinyl acetate, acrylonitrile, and styrene, as needed.

[0166] As for the polymerization mechanism of the (meth)acrylic adhesive resin (b) involved in this embodiment, free radical polymerization, anionic polymerization, cationic polymerization, etc. can be cited. Considering the manufacturing 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, free radical polymerization is preferred.

[0167] When polymerization is carried out via free radical polymerization, examples of free radical polymerization initiators include organic peroxides such as benzoyl peroxide, di-tert-butyl peroxide, dicumyl peroxide, 3,3,5-trimethylhexanoyl peroxide, di-2-ethylhexyl peroxide, methyl ethyl ketone peroxide, tert-butyl peroxide, tert-butyl peroxide, di-tert-butyl peracetate, tert-butyl peroxide, tert-butyl peroxide-2-hexanoate, tert-butyl peroxide-2-ethylhexanoate, tert-butyl peroxide-3,5,5-trimethylhexanoate, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, tert-butyl peroxide, and di-tert-pentyl 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-cyanopentanoic acid.

[0168] When polymerization is carried out via emulsion polymerization, among these free radical polymerization initiators, water-soluble inorganic peroxides such as ammonium persulfate, potassium persulfate, and sodium persulfate, and water-soluble azo compounds containing intramolecular carboxyl groups such as 4,4'-azobis-4-cyanopentanoic acid are preferred. Considering the influence of ions on the surface of electronic components, azo compounds containing intramolecular carboxyl groups such as ammonium persulfate and 4,4'-azobis-4-cyanopentanoic acid are further preferred, and particularly preferred are azo compounds containing intramolecular carboxyl groups such as 4,4'-azobis-4-cyanopentanoic acid.

[0169] In the adhesive resin layer (B) of this embodiment, in addition to the adhesive resin (B1), it is preferable to further include a crosslinking agent (B2) having two or more crosslinking functional groups in one molecule.

[0170] A crosslinking agent (B2) with two or more crosslinking functional groups in one molecule is used to react with the functional groups of the adhesive resin (B1) to adjust the adhesion and cohesion.

[0171] 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, trimethylolpropane toluene diisocyanate triadduct, polyisocyanates, diphenylmethane diisocyanate, and toluene diisocyanate; and trimethylolpropane-tri-β-aziridinylpropionate, tetramethylolpropane-tri-β-aziridinylpropionate, etc. Aziridine compounds such as β-aziridine propionate, 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-phenylenediamine and 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane; and melamine compounds such as hexamethoxyhydroxymethyl melamine. These can be used alone or in combination of two or more.

[0172] These preferably include one or more compounds selected from epoxy compounds, isocyanate compounds, and aziridine compounds.

[0173] The content of crosslinking agent (B2) is generally preferably within the range where the number of functional groups in crosslinking agent (B2) does not exceed the number of functional groups in adhesive resin (B1). However, in cases where new functional groups are generated through the crosslinking reaction, or where the crosslinking reaction is slow, it may be contained in excess as needed.

[0174] The content of crosslinking agent (B2) in the adhesive resin layer (B) is preferably 0.1 to 10 parts by mass relative to 100 parts by mass of adhesive resin (B1), more preferably 0.5 to 5 parts by mass.

[0175] From the viewpoint of improving adhesion to the support substrate, the adhesive resin layer (B) in this embodiment preferably includes a tackifying resin in addition to the adhesive resin (B1). The presence of a tackifying resin in the adhesive resin layer (B) makes it easier to adjust the adhesion to the support substrate at around room temperature, which is therefore preferable. As the tackifying resin, a tackifying resin with a softening point of 100°C or higher is preferred. Specific examples of tackifying resins include rosin-based resins such as rosin derivatives that have undergone esterification or other treatments; terpene resins such as α-pinene, β-pinene, dipentene, and terpene phenol resins; natural rosins such as rubber-based, wood-based, and tall oil-based rosins; petroleum resins that have undergone hydrogenation, disproportionation, polymerization, or maleication of these natural rosins; and coumarone-indene resins, etc.

[0176] Among these, substances with a softening point in the range of 100–160°C are more preferred, and substances in the range of 120–150°C are particularly preferred. Using a tackifying resin with a softening point within the above range not only reduces contamination of the support substrate and leaves less residue, but also further improves adhesion to the support substrate in the working environment. Furthermore, using a polymeric rosin ester-based tackifying resin not only reduces contamination of the support substrate and leaves less residue, but also improves adhesion to the support substrate in an environment of 80–130°C. In the case of a heat-expanding adhesive containing thermally expandable microspheres, the microspheres can be further easily peeled off from the support substrate after expansion.

[0177] The proportion of the tackifying resin can be appropriately selected in a way that adjusts the elastic modulus of the adhesive resin layer (B) to a desired predetermined range, and there are no particular limitations. However, considering the elastic modulus and initial peel force of the adhesive resin layer (B), it is preferably 1 to 100 parts by weight relative to 100 parts by weight of the adhesive resin (B1). If the proportion of the tackifying resin relative to 100 parts by weight of the adhesive resin (B1) is above the lower limit mentioned above, there is a tendency for good adhesion to the support substrate during operation. On the other hand, if it is below the upper limit mentioned above, there is a tendency for good adhesion to the support substrate at room temperature. Considering both adhesion to the support substrate and adhesion at room temperature, it is further preferable to make the proportion of the tackifying resin relative to 100 parts by weight of the adhesive resin (B1) 2 to 50 parts by weight. In addition, the acid value of the tackifying resin is preferably 30 or less. If the acid value of the tackifying resin is below the upper limit mentioned above, there is a tendency for residue to be difficult to form on the support substrate upon peeling.

[0178] The adhesive resin layer (B) may include additives such as plasticizers as other components. When the total content of the adhesive resin layer (B) is set to 100% by mass, the total content of the adhesive resin (B1), crosslinking agent (B2), and tackifying resin in the adhesive resin layer (B) is preferably 50% by mass or more, more preferably 70% by mass or more, further preferably 90% by mass or more, and particularly preferably 95% by mass or more. Furthermore, when the adhesive resin layer (B) is composed of a heat-expanding adhesive, when the total content of the adhesive resin layer (B) is set to 100% by mass, the total content of the adhesive resin (B1), crosslinking agent (B2), tackifying resin, gas-generating component, and heat-expanding microspheres in the adhesive resin layer (B) is preferably 50% by mass or more, more preferably 70% by mass or more, further preferably 90% by mass or more, and particularly preferably 95% by mass or more.

[0179] The thickness of the adhesive resin layer (B) is not particularly limited, but is preferably 5 μm or more and 300 μm or less, and more preferably 20 μm or more and 150 μm or less.

[0180] The adhesive resin layer (B) can be formed, for example, by applying an adhesive coating liquid to the substrate layer 10, or by transferring the adhesive resin layer (B) formed on the partition to the substrate layer 10.

[0181] As a method for applying the adhesive coating liquid, conventionally known coating methods can be used, such as roller coating, reverse roller coating, gravure roller coating, bar coating, corner wheel coating, and die coating. There are no particular limitations on the drying conditions of the coated adhesive; generally, drying at a temperature range of 80–200°C for 10 seconds to 10 minutes is preferred. More preferably, drying at 80–170°C for 15 seconds to 5 minutes is preferred. To fully promote the crosslinking reaction between the crosslinking agent and the adhesive, the adhesive coating liquid can be heated at 40–80°C for approximately 5–300 hours after drying.

[0182] Furthermore, the substrate layer 10 and the adhesive resin layer (B) can be formed by co-extrusion molding, or by laminating (delaminating) the film-like substrate layer 10 and the film-like adhesive resin layer (B).

[0183] <Other Layers>

[0184] The adhesive film 50 involved in this embodiment may be further provided with, for example, an uneven absorption layer, an impact absorption layer, an easy-to-adhere layer, etc., between the substrate layer 10 and the adhesive resin layer (A) or between the substrate layer 10 and the adhesive resin layer (B), without impairing the effect of this embodiment.

[0185] The uneven absorbing layer is preferably formed from natural rubber, synthetic rubber, or a synthetic resin with rubber elasticity, having a Shore D hardness of 50 or less, preferably 40 or less, as determined by a Shore D hardness tester according to ASTM D-2240. The thickness of the uneven absorbing layer is, for example, 500 μm or less, preferably 5 to 300 μm, and more preferably 10 to 150 μm.

[0186] Examples of synthetic rubbers or synthetic resins include nitrile-based, diene-based, and acrylic-based synthetic rubbers; thermoplastic elastomers such as polyolefin-based and polyester-based elastomers; ethylene-vinyl acetate copolymers; polyurethane; polybutadiene; and flexible polyvinyl chloride, all of which possess rubber-like elasticity. Furthermore, even polymers that are inherently rigid, such as polyvinyl chloride, can be used in this embodiment to acquire rubber-like elasticity through combination with plasticizers, softeners, and other compounding agents. Additionally, the adhesive resins exemplified in the adhesive resin layer (A) and adhesive resin layer (B) described above are preferably used for forming the uneven absorbent layer.

[0187] The embodiments of the present invention have been described above, but these are merely examples of the invention, and various other configurations may also be employed.

[0188] Furthermore, the present invention is not limited to the above-described embodiments, and variations and improvements within the scope of achieving the objectives of the present invention are included in the present invention.

[0189] Example

[0190] The present invention will be specifically described below through examples, but the present invention is not limited thereto.

[0191] The details of the materials used in the fabrication of the adhesive film are as follows.

[0192] <Adhesive Resin Solution SA1>

[0193] In deionized pure water, 0.5 parts by mass of 4,4'-azobis-4-cyanopentanoic acid (manufactured by Otsuka Chemical Co., Ltd., trade name: ACVA) as a polymerization initiator, 74.3 parts by mass of n-butyl acrylate and 13.7 parts by mass of methyl methacrylate as monomers (a1), 9 parts by mass of 2-hydroxyethyl methacrylate as monomer (a2), and 3 parts by mass of a polymerizable 1-propenyl group introduced into the benzene ring of the ammonium salt of polyoxyethylene nonylphenyl ether sulfate (manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.; trade name: Acuro HS-1025) as a polymerizable surfactant were added. Emulsion polymerization was carried out at 70–72°C for 8 hours with stirring to obtain an acrylic resin emulsion. This emulsion was neutralized with ammonia (pH = 7.0) to obtain an adhesive resin solution SA1 with a solid content of 42.5%.

[0194] <Adhesive Resin Solution SA2>

[0195] In deionized pure water, 0.5 parts by mass of ammonium persulfate as a polymerization initiator, 63 parts by mass of 2-ethylhexyl acrylate, 21 parts by mass of n-butyl acrylate, and 9 parts by mass of methyl methacrylate as monomers (a1), 3 parts by mass of 2-hydroxyethyl methacrylate as monomer (a2), 1 part by mass of polytetramethylene ether diol diacrylate (manufactured by Nippon Yushi Co., Ltd., trade name: ADT-250) as monomer (a3), and 2 parts by mass of a polymerizable 1-propenyl group introduced into the benzene ring of the ammonium salt of polyoxyethylene nonylphenyl ether sulfate (manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd., trade name: Acuro HS-1025) as a polymerizable surfactant were added. Emulsion polymerization was carried out at 70–72°C for 8 hours with stirring to obtain an acrylic resin emulsion. This emulsion was neutralized with ammonia (pH = 7.0) to obtain an adhesive resin solution SA2 with a solid content concentration of 56.5%.

[0196] <Adhesive Coating Liquid A1>

[0197] 57.4 parts by weight of adhesive resin solution SA1, 42.6 parts by weight of adhesive resin solution SA2, 0.4 parts by weight of dimethylethanolamine, and 3.4 parts by weight of epoxy compound (manufactured by Nagase ChemteX, Ex-1610) as a crosslinking agent were mixed to obtain adhesive coating solution A1.

[0198] <Adhesive Resin Solution SB1>

[0199] In a mixed solvent containing ethyl acetate and toluene, 0.536 parts by weight of tert-butyl peroxide-2-ethylhexanoate (manufactured by Nippon Yushu Co., Ltd., trade name: Perbutyl O (registered trademark)) as a polymerization initiator, 34.9 parts by weight of 2-ethylhexyl acrylate, 41 parts by weight of n-butyl acrylate, and 14.7 parts by weight of ethyl acrylate as monomers (b1), and 9.4 parts by weight of 2-hydroxyethyl methacrylate as monomers (b2) were added. Solution polymerization was carried out at 83–87°C for 11 hours with stirring to obtain an acrylic resin solution with a solid content of 45% by weight. This was designated as adhesive resin solution SB1.

[0200] <Adhesive Coating Liquid B1>

[0201] 100 parts by weight of adhesive resin solution SB1 and 0.9 parts by weight of isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals Co., Ltd., trade name: Olester P49-75S) (2 parts by weight relative to 100 parts by weight of adhesive resin) were mixed, and the concentration of solid components was adjusted to 40% using ethyl acetate to obtain adhesive coating solution B1.

[0202] <Adhesive Coating Liquid B2>

[0203] 100 parts by weight of adhesive resin solution SB1, 2.25 parts by weight of polymeric rosin ester tackifier (manufactured by Arakawa Chemical Industry Co., Ltd., trade name: Pencel D-125) (5 parts by weight relative to 100 parts by weight of adhesive resin), 1.2 parts by weight of isocyanate crosslinking agent (manufactured by Mitsui Chemicals Co., Ltd., trade name: Olest P49-75S) (2 parts by weight relative to 100 parts by weight of adhesive resin), and 6.75 parts by weight of thermally expandable microspheres (manufactured by Sekisui Chemical Industry Co., Ltd., trade name: Advancell EM-503) (15 parts by weight relative to 100 parts by weight of adhesive resin) were mixed, and the solid component concentration was adjusted to 30% using ethyl acetate to prepare adhesive coating solution B2.

[0204] [Example 1]

[0205] An adhesive resin layer (A) with a thickness of 10 μm, formed by drying adhesive coating liquid A1, is provided on a polyethylene terephthalate (PET) film (38 μm thick) serving as the substrate layer. Next, an uneven absorbent layer with a thickness of 20 μm, formed by drying adhesive coating liquid B1, is provided on the surface of the PET film opposite to the adhesive resin layer (A). On this layer, a heat-release type adhesive resin layer (B) with a thickness of 30 μm, formed by drying adhesive coating liquid B2, is provided, thus obtaining an adhesive film.

[0206] The adhesive resin layer (B) of the obtained adhesive film was bonded to a 320 mm square SUS substrate. As an electronic component, a 5 mm square semiconductor chip was placed on the adhesive resin layer (A) of the adhesive film in a grid pattern with a 2 mm interval and then sealed to obtain a structure.

[0207] Next, the resulting structure was pre-baked by heating it at 100°C for 30 minutes.

[0208] Here, for the pre-baked structure, the positional offset of the semiconductor chip was visually observed and evaluated using the following benchmarks.

[0209] ○: No electronic components are misaligned.

[0210] ×: At least one electronic component has moved, shifting from its original position.

[0211] Furthermore, for the pre-baked structure, the presence or absence of thermal expansion of the adhesive resin layer (B) was visually observed, and the following criteria were used for evaluation. The results are shown in Table 1.

[0212] ○: The appearance of the adhesive resin layer (B) remains unchanged.

[0213] ×: The adhesive resin layer (B) has swelled.

[0214] Next, using a compression molding machine, multiple semiconductor chips on the adhesive resin layer (A) are sealed by compression molding at 135°C using granular epoxy resin sealant (manufactured by Sumitomo Bakelite, product name: G730) to obtain an electronic device.

[0215] Next, the positional offset of the semiconductor chip was visually observed and evaluated using the following criteria. The results are shown in Table 1.

[0216] ○: No electronic components are misaligned.

[0217] ×: At least one electronic component has moved, shifting from its original position.

[0218] [Examples 2-6]

[0219] The conditions for the heat treatment in the pre-baking process were changed to those shown in Table 1. Otherwise, the structure and electronic device were fabricated using the same method as in Example 1, and the same evaluations were performed as in Example 1.

[0220] The results are shown in Table 1.

[0221] [Comparative Example 1]

[0222] Except for the absence of a pre-baking process, the structure and electronic device were fabricated using the same method as in Example 1, and were evaluated in the same manner as in Example 1.

[0223] The results are shown in Table 1.

[0224] [Table 1]

[0225]

[0226] Symbol Explanation

[0227] A: Adhesive resin layer, B: Adhesive resin layer, 10: Substrate layer, 10A: First side, 10B: Second side, 50: Adhesive film, 60: Sealing material, 70: Electronic component, 80: Support substrate, 100: Structure, 200: Electronic device, 300: Electronic device, 310: Wiring layer, 320: Bump, 400: Electronic device.

[0228] This application claims priority based on Japanese Patent Application No. 2019-046792, filed on March 14, 2019, and incorporates all of its disclosures in this application.

Claims

1. A method for manufacturing an electronic device, comprising at least the following steps: Preparation process for a structure containing an adhesive film, electronic components, and a supporting substrate; A pre-baking process that heats the structure; and A sealing process in which the electronic components are sealed using a sealing material. The adhesive membrane comprises: Substrate layer; An adhesive resin layer A disposed on the first side of the substrate layer for temporarily fixing electronic components; and An adhesive resin layer B is disposed on the second side of the substrate layer and whose adhesive strength is reduced by external stimulation. The electronic component is bonded to the adhesive resin layer A of the adhesive film. The supporting substrate is bonded to the adhesive resin layer B of the adhesive film. The adhesive resin layer A comprises adhesive resin A1 and crosslinking agent A2. When the total content of the adhesive resin layer A is set to 100% by mass, the combined content of the adhesive resin A1 and the crosslinking agent A2 in the adhesive resin layer A is 70% by mass or more. The content of the crosslinking agent A2 is 0.1 parts by weight to 15 parts by weight relative to 100 parts by weight of the adhesive resin A1. The heating temperature in the pre-baking process is above 70°C and below 160°C. The heating time in the pre-baking process is more than 1 minute and less than 80 minutes.

2. The method for manufacturing an electronic device according to claim 1, further comprising a first peeling step after the sealing step: reducing the adhesiveness of the adhesive resin layer B by applying external stimulation to peel the support substrate from the structure.

3. The method for manufacturing an electronic device according to claim 2, further comprising a second peeling step after the first peeling step: peeling the adhesive film from the electronic component.

4. The method for manufacturing an electronic device according to claim 1 or 2, wherein the sealing material is an epoxy resin-based sealing material.

5. The method for manufacturing an electronic device according to claim 1 or 2, wherein the adhesive resin constituting the adhesive resin layer A comprises one or more selected from (meth)acrylic adhesive resin, silicone adhesive resin, urethane adhesive resin, olefin adhesive resin and styrene adhesive resin.

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