Method for manufacturing electronic device

Abstract

This method for manufacturing an electronic device comprises, in this order, the steps of: preparing an adhesive film (50) including an adhesive resin layer (B), a substrate layer (A), and an adhesive resin layer (C) in this order, and then attaching a support substrate (80) to the adhesive resin layer (C) side of the adhesive film (50); reducing the amount of volatile components in the adhesive film (50); attaching an electronic component (70) to the adhesive resin layer (B) side of the adhesive film (50); back-grinding the electronic component (70); and forming a metal layer (60) on the back-ground surface of the electronic component (70).

Description

Method for manufacturing an electronic device

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

[0002] In a method for manufacturing an electronic device, after forming a circuit of an electronic component, a process of performing treatment such as back grinding (back surface grinding), ion implantation, laser annealing, sputtering, etc. on the surface opposite to the circuit formation surface of the electronic component is included. In these processes, an adhesive film for protecting the circuit formation surface of the electronic component is used. As a technique related to such an adhesive film, for example, the one described in Patent Document 1 can be cited.

[0003] Patent Document 1 describes an adhesive sheet including an adhesive layer, wherein the adhesive layer includes an adhesive containing a base polymer and a foaming agent having a foaming temperature of 90 °C or higher, and the shear adhesive strength when the adhesive surface of the adhesive sheet is adhered to a silicon chip is 1.0 MPa or higher at an environmental temperature of 25 °C and 0.2 MPa or higher at an environmental temperature of 80 °C. And Patent Document 1 describes that "it is possible to provide an adhesive sheet that can be used for grinding a brittle substrate in the back grinding process of a brittle substrate and is excellent in any of grinding accuracy, low contamination, productivity, and fixing property".

[0004] Japanese Unexamined Patent Application Publication No. 2020-041007

[0005] According to the study by the present inventors, in the process of forming a metal layer on the back ground surface of an electronic component, floating may occur between the support substrate and the adhesive film, and as a result, poor formation of the metal layer may occur. The present invention provides a method for manufacturing an electronic device capable of suppressing the occurrence of floating between the support substrate and the adhesive film.

[0006] The inventors diligently conducted research to achieve the above objectives. As a result, they discovered that by reducing the amount of volatile components in the adhesive film after bonding the support substrate and the adhesive film, it is possible to suppress the occurrence of lifting between the support substrate and the adhesive film in the process of forming a metal layer on the back-ground surface of an electronic component, thus completing the present invention.

[0007] According to the present invention, a method for manufacturing the following electronic device is provided.

[0008] [1] A method for manufacturing an electronic device, comprising the steps of: preparing an adhesive film containing an adhesive resin layer (B), a base layer (A), and an adhesive resin layer (C) in that order; then attaching a support substrate to the adhesive resin layer (C) side of the adhesive film; reducing the amount of volatile components in the adhesive film; attaching an electronic component to the adhesive resin layer (B) side of the adhesive film; backgrinding the electronic component; and forming a metal layer on the backgrinded surface of the electronic component, in that order. [2] The method for manufacturing an electronic device according to [1], wherein the step of reducing the amount of volatile components in the adhesive film includes a step of reducing the amount of volatile components in the adhesive film by heat treatment. [3] The method for manufacturing an electronic device according to [2], wherein the heating time in the step of reducing the amount of volatile components in the adhesive film by heat treatment is 0.1 hours or more and 48 hours or less. [4] The method for manufacturing an electronic device according to [2] or [3] above, wherein the heating temperature in the step of reducing the amount of volatile components in the adhesive film by the heat treatment is 100°C or more and 150°C or less. [5] The method for manufacturing an electronic device according to any one of [1] to [4] above, wherein the electronic component includes a wafer. [6] The method for manufacturing an electronic device according to [5] above, wherein the wafer includes a sapphire wafer, an indium-phosphorus wafer, a silicon-carbon wafer, a gallium-nitrogen wafer, a gallium-arsenide wafer, a silicon wafer, a germanium wafer, a germanium-arsenide wafer, a gallium-phosphorus wafer, a gallium-arsenide-aluminum wafer, or a lithium tantalate wafer. [7] The method for manufacturing an electronic device according to any one of [1] to [6] above, wherein the electronic component includes a circuit forming surface. [8] The method for manufacturing an electronic device according to any one of [1] to [7] above, wherein the step of backgrinding the electronic component includes a step of making the thickness of the electronic component 100 μm or less. [9] A method for manufacturing an electronic device according to any one of [1] to [8], wherein the step of forming a metal layer on the back-ground surface of the electronic component is performed under reduced pressure.

[10] A method for manufacturing an electronic device according to any one of [1] to [9] above, wherein at least one selected from the adhesive resin layer (B) and the adhesive resin layer (C) is a layer whose adhesive strength decreases due to external stimuli.

[11] A method for manufacturing an electronic device according to

[10] above, further comprising a step of reducing the adhesive strength of at least one selected from the adhesive resin layer (B) and the adhesive resin layer (C) by external stimuli.

[12] A method for manufacturing an electronic device according to

[10] or

[11] above, wherein at least one selected from the adhesive resin layer (B) and the adhesive resin layer (C) is one or more selected from the group consisting of heat-peelable adhesive resin layers and light-peelable adhesive resin layers.

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

[12] above, wherein the heat-peelable adhesive resin layer is an adhesive resin layer whose adhesive strength decreases or is lost when heated at a temperature exceeding 100°C.

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

[13] above, wherein the adhesive resin (C1) constituting the adhesive resin layer (C) includes one or more selected from the group consisting of (meth)acrylic resins, urethane resins, silicone resins, polyolefin resins, polyester resins, polyamide resins, fluororesins, and styrene-diene block copolymer resins.

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

[14] above, wherein the thickness of the adhesive resin layer (C) is 1 μm or more and 500 μm or less.

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

[15] above, wherein the adhesive resin (B1) constituting the adhesive resin layer (B) includes 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.

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

[16] , wherein the thickness of the adhesive resin layer (B) is 1 μm or more and 500 μm or less.

[18] A method for manufacturing an electronic device according to any one of [1] to

[17] , further comprising an intermediate layer (D) selected between the base layer (A) and the adhesive resin layer (B), and between the base layer (A) and the adhesive resin layer (C).

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

[18] , wherein the intermediate layer (D) includes a layer that hardens upon external stimulation.

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

[18] or

[19] , wherein the intermediate layer (D) includes a crosslinking agent.

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

[20] , wherein the crosslinking agent includes one or more selected from the group consisting of polyfunctional (meth)acrylate compounds and isocyanate compounds.

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

[18] to

[21] , wherein the intermediate layer (D) includes one or more selected from the group consisting of thermal initiators and photoinitiators.

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

[22] , wherein the thermal initiator comprises one or more selected from the group consisting of aromatic ketones, onium salt compounds, organic peroxides, thio compounds, hexaarylbiimidazole compounds, ketoxime ester compounds, borate compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having carbon-halogen bonds, and azo compounds.

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

[22] or

[23] , wherein the photoinitiator comprises an alkylphenone photoinitiator.

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

[18] to

[24] , wherein the thickness of the intermediate layer (D) is 5 μm or more and 1000 μm or less.

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

[25] , wherein the substrate layer (A) comprises a thermoplastic resin.

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

[26] , wherein the thickness of the substrate layer (A) is 1 μm or more and 500 μm or less.

[0009] According to the present invention, it is possible to provide a method for manufacturing an electronic device that can suppress the occurrence of lifting between the support substrate and the adhesive film.

[0010] This is a schematic cross-sectional view showing an example of the structure of the adhesive film of this embodiment. This is a schematic cross-sectional view showing an example of the structure of the adhesive film of this embodiment. This is a schematic cross-sectional view showing an example of the manufacturing method of the electronic device of this embodiment. This is a schematic cross-sectional view showing an example of the manufacturing method of the electronic device of this embodiment.

[0011] <Method for Manufacturing an Electronic Device> First, the method for manufacturing an electronic device according to this embodiment will be described. Figures 1 and 2 are schematic cross-sectional views showing an example of the structure of the adhesive film 50 according to this embodiment. Figures 3 and 4 are schematic cross-sectional views showing an example of the method for manufacturing an electronic device according to this embodiment. The method for manufacturing an electronic device according to this embodiment includes, in this order, preparing an adhesive film 50 containing an adhesive resin layer (B), a base layer (A), and an adhesive resin layer (C), then attaching a support substrate 80 to the adhesive resin layer (C) side of the adhesive film 50, reducing the amount of volatile components in the adhesive film 50, attaching an electronic component 70 to the adhesive resin layer (B) side of the adhesive film 50, back-grinding the electronic component, and forming a metal layer 60 on the back-grinded surface of the electronic component.

[0012] As described above, our investigations have revealed that in the process of forming a metal layer on the back-ground surface of an electronic component, lifting may occur between the support substrate and the adhesive film, resulting in a failure to form the metal layer properly. Based on the above findings, our inventors conducted further investigations and found that in the process of forming a metal layer on the back-ground surface of an electronic component, volatile components are generated as gas from the adhesive film, and this generated gas creates a gap between the support substrate and the adhesive film, resulting in lifting between the support substrate and the adhesive film. In particular, it was found that lifting is more likely to occur between the support substrate and the adhesive film when forming the metal layer using high-temperature, reduced-pressure processes such as sputtering, vapor deposition, plating, and CVD. Based on the above findings, our inventors conducted further investigations. As a result, we found that by reducing the amount of volatile components in the adhesive film after bonding the support substrate and the adhesive film, the generation of gas derived from volatile components from the adhesive film can be suppressed in the process of forming a metal layer on the back-ground surface of an electronic component, thereby suppressing the occurrence of lifting between the support substrate and the adhesive film. As described above, according to this embodiment, it is possible to provide a method for manufacturing an electronic device that can suppress the occurrence of lifting between the support substrate and the adhesive film in the process of forming a metal layer on the back-ground surface of an electronic component.

[0013] The following describes each step in the manufacturing method of the electronic device according to this embodiment.

[0014] [Steps to prepare an adhesive film 50 containing an adhesive resin layer (B), a base layer (A), and an adhesive resin layer (C) in this order, and then attach a support substrate 80 to the adhesive resin layer (C) side of the adhesive film 50] First, an adhesive film 50 is prepared containing an adhesive resin layer (B), a base layer (A), and an adhesive resin layer (C) in this order, and then a support substrate 80 is attached to the adhesive resin layer (C) side of the adhesive film 50.

[0015] The adhesive film 50, which includes an adhesive resin layer (B), a base layer (A), and an adhesive resin layer (C) in this order, will be described later.

[0016] A protective film may be attached to the adhesive resin layer (C), and the protective film can be peeled off to allow the exposed surface of the adhesive resin layer (C) to be attached to the surface of the support substrate 80. For example, the support substrate 80 can be a quartz substrate, a glass substrate, a SUS substrate, etc.

[0017] [Step to reduce the amount of volatile components in the adhesive film 50] Next, the amount of volatile components in the adhesive film 50 is reduced. The step to reduce the amount of volatile components in the adhesive film 50 preferably includes a step to reduce the amount of volatile components in the adhesive film 50 by a treatment that includes one or more selected from the group consisting of heat treatment and vacuum treatment, and more preferably includes a step to reduce the amount of volatile components in the adhesive film 50 by heat treatment.

[0018] In the step of reducing the amount of volatile components in the adhesive film 50 by heat treatment, the heating time is preferably 0.1 hours to 48 hours, more preferably 0.3 hours to 24 hours, even more preferably 0.5 hours to 12 hours, even more preferably 0.6 hours to 6 hours, even more preferably 0.7 hours to 3 hours, and even more preferably 0.8 hours to 2 hours, from the viewpoint of further suppressing the occurrence of lifting between the support substrate 80 and the adhesive film 50, and from the viewpoint of improving productivity.

[0019] In the step of reducing the amount of volatile components in the adhesive film 50 by heat treatment, the heating temperature is preferably 100°C to 150°C, more preferably 110°C to 140°C, and even more preferably 120°C to 135°C, from the viewpoint of further suppressing the occurrence of lifting between the support substrate 80 and the adhesive film 50. In this embodiment, if the adhesive film 50 includes at least one of the adhesive resin layer (B) and adhesive resin layer (C) selected from external stimuli, the heating temperature in the step of reducing the amount of volatile components in the adhesive film 50 is preferably below the temperature at which the adhesive strength of the layer whose adhesive strength is reduced by external stimuli decreases. The method of heat treatment of the adhesive film 50 is not particularly limited, but generally known heat treatment methods such as ovens, dryers, heating rolls, and drying ovens can be used.

[0020] When the adhesive film 50 is subjected to reduced pressure treatment, the pressure during the reduced pressure is preferably 100 Pa or more and 10,000 Pa or less, from the viewpoint of further suppressing the occurrence of lifting between the support substrate 80 and the adhesive film 50. The method for performing reduced pressure treatment on the adhesive film 50 is not particularly limited, but a generally known reduced pressure method such as a vacuum dryer can be used. The amount of volatile components can be adjusted by adjusting the conditions of the heat treatment and reduced pressure treatment, but when heat treatment is performed at a temperature exceeding 100°C, it is preferable to set the pressure during reduced pressure to 500 Pa or more in order to prevent delamination between the electronic component 70 and the adhesive film 50.

[0021] Whether the amount of volatile components in the adhesive film 50 has decreased can be determined by known methods such as thermogravimetric analysis.

[0022] [Step of attaching electronic components 70 to the adhesive resin layer (B) side of the adhesive film 50] Next, the electronic components 70 are attached to the adhesive resin layer (B) side of the adhesive film 50. In this step, the structure 100 can be obtained by arranging the electronic components 70 on the adhesive resin layer (B) of the adhesive film 50 attached to the support substrate 80. The electronic components 70 can be any known electronic components, but preferably include one or more selected from the group consisting of semiconductor chips such as ICs, LSIs, discretes, light-emitting diodes, and photodetectors, semiconductor panels, semiconductor packages, wafers, and semiconductor substrates, and more preferably include wafers.

[0023] The wafers of this embodiment preferably include sapphire wafers, indium-phosphorus wafers, silicon-carbon wafers, gallium-nitrogen wafers, gallium-arsenide wafers, silicon wafers, germanium wafers, germanium-arsenide wafers, gallium-phosphorus wafers, gallium-arsenide-aluminum wafers, or lithium tantalate wafers.

[0024] The electronic component 70 of this embodiment preferably includes a circuit-forming surface. When the electronic component 70 includes a circuit-forming surface, the circuit-forming surface side of the electronic component 70 is attached to the adhesive film 50. The circuit-forming surface of the electronic component 70 of this embodiment has, for example, circuits such as wiring, capacitors, diodes, or transistors formed on its surface. The circuit-forming surface may also be plasma-treated. Furthermore, the circuit-forming surface of the electronic component 70 may have an uneven structure, for example, by having bump electrodes.

[0025] A bump electrode is, for example, one that is joined to an electrode formed on a mounting surface when mounting an electronic device to a mounting surface, thereby forming an electrical connection between the electronic device and the mounting surface (such as a printed circuit board). The bump electrode preferably includes one or more types of bump electrodes selected from the group consisting of ball bumps, printed bumps, stud bumps, plated bumps, and pillar bumps. That is, the uneven structure of this embodiment preferably includes bump electrodes. The type of metal constituting the bump electrode is not particularly limited, but preferably includes one or more types selected from the group consisting of silver, gold, copper, tin, lead, or bismuth and alloys thereof.

[0026] When the uneven structure of this embodiment includes bump electrodes, if the height of the bump electrodes is H [μm] and the thickness of the adhesive resin layer (B) is d [μm], then H / d is preferably 1 or less, more preferably 0.85 or less, and even more preferably 0.7 or less. When H / d is below the above upper limit, the thickness of the adhesive film 50 can be made thinner while further suppressing the occurrence of lifting between the support substrate 80 and the adhesive film 50. The lower limit of H / d is not particularly limited, but for example, it is 0.01 or more. The height of the bump electrodes is generally 2 μm or more and 600 μm or less.

[0027] [Backgrinding process for electronic component 70] Next, the electronic component 70 is backgrinded. In the backgrinding process for the electronic component 70, the electronic component 70 is ground to a predetermined thickness. If the electronic component 70 includes a circuit forming surface, in the backgrinding process for the electronic component 70, the surface of the electronic component 70 opposite to the circuit forming surface is ground to a predetermined thickness.

[0028] The thickness of the electronic component 70 before grinding is appropriately determined according to the diameter, type, etc. of the electronic component 70, and the thickness of the electronic component 70 after grinding is appropriately determined according to the size of the chip obtained, the type of circuit, etc. The back-grinding step of the electronic component 70 preferably includes a step to reduce the thickness of the electronic component 70 to 100 μm or less, more preferably includes a step to reduce the thickness of the electronic component 70 to 80 μm or less, even more preferably includes a step to reduce the thickness of the electronic component 70 to 60 μm or less, even more preferably includes a step to reduce the thickness of the electronic component 70 to 40 μm or less, and even more preferably includes a step to reduce the thickness of the electronic component 70 to 20 μm or less. The lower limit of the thickness of the electronic component 70 after grinding in the back-grinding step of the electronic component 70 is not particularly limited, but for example it may be greater than 0 μm, 0.01 μm or more, or 0.1 μm or more.

[0029] The grinding method used in the process of back-grinding the electronic component 70 is not particularly limited, and any known grinding method can be used. For example, the electronic component 70 and the grinding wheel may be ground while cooling them with grinding water, or they may be ground using a dry polishing method without using grinding water.

[0030] In the process of back-grinding the electronic component 70, chemical etching may be performed after grinding. Chemical etching is performed by methods such as immersing the electronic component 70 in a chemical etching solution. Chemical etching is performed for purposes such as removing distortion generated on the back surface of the electronic component 70, further thinning of the electronic component 70, removal of oxide films, and pretreatment when forming electrodes on the back surface. The etching solution includes, for example, one or more types selected from the group consisting of acidic aqueous solutions consisting of one or a mixture of hydrofluoric acid, nitric acid, sulfuric acid, acetic acid, etc., and alkaline aqueous solutions such as potassium hydroxide aqueous solution and sodium hydroxide aqueous solution.

[0031] [Step of forming a metal layer 60 on the back-ground surface of the electronic component 70] Next, a metal layer 60 is formed on the back-ground surface of the electronic component 70. The metal layer 60 can be formed by, for example, sputtering, vapor deposition, plating, CVD, etc.

[0032] The metal layer 60 preferably contains one or more selected from the group consisting of silver, gold, copper, tin, lead, aluminum, nickel, titanium, or bismuth and their alloys.

[0033] The thickness of the metal layer 60 is preferably 100 μm or less, more preferably 80 μm or less, even more preferably 60 μm or less, even more preferably 40 μm or less, and even more preferably 20 μm or less. The lower limit of the thickness of the metal layer 60 is not particularly limited, but for example it may be greater than 0 μm, 0.01 μm or more, or 0.1 μm or more. The thickness of the metal layer 60 is preferably greater than 0 μm and 100 μm or less, more preferably greater than 0 μm and 80 μm or less, even more preferably greater than 0 μm and 60 μm or less, even more preferably 0.01 μm or more and 40 μm or less, and even more preferably 0.1 μm or more and 20 μm or less.

[0034] The step of forming a metal layer 60 on the back-ground surface of the electronic component 70 is preferably carried out under reduced pressure. The pressure during the reduction process in the step of forming a metal layer 60 on the back-ground surface of the electronic component 70 may be any low pressure state reduced from atmospheric pressure by a vacuum device, but may be, for example, 1000 Pa or less, 100 Pa or less, or 10 Pa or less.

[0035] The step of forming a metal layer 60 on the back-ground surface of the electronic component 70 is preferably carried out under high-temperature conditions. The temperature of the adhesive film 50 in the step of forming a metal layer 60 on the back-ground surface of the electronic component 70 is preferably 60°C to 230°C, more preferably 80°C to 210°C, even more preferably 100°C to 190°C, even more preferably 120°C to 170°C, and even more preferably 140°C to 170°C.

[0036] [Other Steps] The method for manufacturing the electronic device of this embodiment further includes a step of reducing the adhesive strength of at least one of the adhesive resin layers (B) and adhesive resin layers (C) by external stimulation. This step allows the support substrate 80 or the electronic device 200 including the electronic components 70 to be easily peeled off from the structure 100. When this step is included, the adhesive film 50 of this embodiment preferably includes a layer in which the adhesive strength is reduced by external stimulation, at least one of the adhesive resin layers (B) and adhesive resin layers (C) is selected. The external stimulation preferably includes one or more selected from the group consisting of light irradiation and heat treatment, and more preferably includes heat treatment from the viewpoint of further suppressing the occurrence of lifting between the support substrate 80 and the adhesive film 50. From the viewpoint of work efficiency, the heating time during the heat treatment is preferably 0.1 hours to 48 hours, more preferably 0.3 hours to 24 hours, even more preferably 0.5 hours to 12 hours, and more preferably 0.8 hours to 6 hours. Furthermore, the heating temperature during the heat treatment is not particularly limited as long as it is a temperature at which the adhesive strength of the layer whose adhesive strength is reduced by external stimuli decreases. However, from the viewpoint of work efficiency, it is preferably 100°C to 150°C, more preferably 110°C to 140°C, and even more preferably 120°C to 130°C.

[0037] The method for manufacturing the electronic device of this embodiment may further include a step of peeling the adhesive film 50 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 mechanical peeling and peeling after reducing the adhesive strength of the surface of the adhesive film 50.

[0038] The method for manufacturing electronic components according to this embodiment may include other steps, as long as they do not impair the effects of this embodiment.

[0039] The manufacturing method of the electronic component of this embodiment includes any steps that are commonly performed in the manufacturing process of electronic components, such as a resist process, a developing process, an ashing process, a sputtering process, a dicing process, a die bonding process, a wire bonding process, a flip-chip connection process, a curing and heating test process, a sealing process, and a reflow process.

[0040] <Adhesive Film 50> The adhesive film 50 of this embodiment will now be described. Figures 1 and 2 are schematic cross-sectional views showing an example of the structure of the adhesive film 50 of this embodiment.

[0041] As shown in Figure 1, the adhesive film 50 of this embodiment includes an adhesive resin layer (B), a base layer (A), and an adhesive resin layer (C) in this order.

[0042] The overall thickness of the adhesive film 50 is preferably 10 μm to 1000 μm, and more preferably 20 μm to 500 μm, from the viewpoint of further suppressing the occurrence of lifting between the support substrate 80 and the adhesive film 50 and improving the performance balance between mechanical properties and handling ease.

[0043] Next, each layer constituting the adhesive film 50 of this embodiment will be described.

[0044] [Base Material Layer (A)] The base material layer (A) is a layer provided for the purpose of making the handling properties, mechanical properties, heat resistance, and other properties of the adhesive film 50 better. The base material layer (A) preferably contains a thermoplastic resin. The thermoplastic resin preferably includes one or more selected from the group consisting of 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 polymetaxylene adipamide; polyacrylate; polymethacrylate; polyvinyl chloride; polyvinylidene chloride; polyimide; polyetherimide; ethylene-vinyl acetate copolymer; polyacrylonitrile; polycarbonate; polystyrene; ionomer; polysulfone; polyether sulfone; and polyphenylene ether. From the perspective of excellent balance in transparency, mechanical strength, price, etc., more preferably, it includes one or more selected from the group consisting of polypropylene, polyethylene terephthalate, polyethylene naphthalate, polyamide, and polyimide, and even more preferably, it includes one or more selected from the group consisting of polyethylene terephthalate and polyethylene naphthalate.

[0045] The base material layer (A) may be a single layer or two or more layers. Also, the base material layer (A) may be a stretched film or a film stretched in one axial direction or two axial directions. From the perspective of improving the mechanical strength of the base material layer (A), it preferably includes a film stretched in one axial direction or two axial directions.

[0046] From the perspective of obtaining good film properties, the thickness of the base material layer (A) is preferably 1 μm or more and 500 μm or less, more preferably 5 μm or more and 300 μm or less, and even more preferably 10 μm or more and 250 μm or less. The base material layer (A) may be surface-treated to improve the adhesion to other layers. Specifically, corona treatment, plasma treatment, undercoat treatment, primer coat treatment, etc. may be performed.

[0047] [Adhesive Resin Layer (B)] The adhesive film 50 of the present embodiment includes an adhesive resin layer (B) on one surface of the base material layer (A). The adhesive resin layer (B) is, for example, a layer for temporarily fixing the electronic component 70 by contacting the surface of the electronic component 70.

[0048] As described above, in the adhesive film 50 of the present embodiment, preferably, at least one selected from the adhesive resin layer (B) and the adhesive resin layer (C) includes a layer whose adhesive force decreases due to an external stimulus. In the adhesive film 50 of the present embodiment, at least one selected from the adhesive resin layer (B) and the adhesive resin layer (C) preferably includes one or more selected from the group consisting of a heat-release type adhesive resin layer and a photo-release type adhesive resin layer, and more preferably includes a heat-release type adhesive resin layer. The heat-release type adhesive resin layer preferably includes one or more selected from the group consisting of a heat-expandable adhesive containing a gas generation component, a heat-expandable adhesive containing heat-expandable microspheres that can expand by heat to reduce the adhesive force, and a heat-expandable adhesive in which the adhesive component undergoes a crosslinking reaction by heat to reduce the adhesive force, and more preferably includes a heat-expandable adhesive containing a gas generation component or heat-expandable microspheres.

[0049] The heat-peelable adhesive resin layer includes an adhesive resin layer whose adhesive strength decreases or is lost when heated at a temperature preferably above 100°C, more preferably above 110°C, even more preferably above 120°C, even more preferably above 130°C, even more preferably above 140°C, and even more preferably above 150°C. The heat-peelable adhesive resin layer preferably includes a material that does not peel at temperatures below 100°C, but whose adhesive strength decreases or is lost at temperatures above 100°C, and has an adhesive strength sufficient to prevent the adhesive film 50 from peeling off the support substrate 80 during the manufacturing process of the electronic device. Here, the decrease or loss of adhesive strength when heated at a temperature above 100°C can be evaluated, for example, by measuring the peel strength from the stainless steel plate after attaching the adhesive resin layer (C) side to a stainless steel plate, performing a heat treatment at 90°C for 1 hour, and then heating at a temperature above 100°C for 2 minutes. The specific heating temperature when heating to a temperature exceeding 100°C is set to a temperature higher than the temperature at which gas is generated or the temperature at which the thermally expandable microspheres expand, and is set appropriately depending on the type of gas generated or the thermally expandable microspheres. In this embodiment, loss of adhesive strength refers to, for example, when the 180° peel strength measured under conditions of 23°C and a tensile speed of 300 mm / min falls below 0.5 N / 25 mm.

[0050] The gas-generating components used in heat-expandable adhesives are preferably azo compounds; azide compounds; meldrum acid derivatives; inorganic blowing agents such as ammonium carbonate, ammonium bicarbonate, sodium bicarbonate, ammonium nitrite, sodium boro hydroxide, and various azides; water; salt fluoride alkane compounds such as trichloromonofluoromethane and dichloromonofluoromethane; azo compounds such as azobisisobutyronitrile, azodicarbonamide, and barium azodicarboxylate; and p-toluenesulfonyl hydrazide and diphenylsulfone-3,3'-disulfonyl hydrazide. The gas generating component may be added to the heat-expandable adhesive, or it may be directly bonded to the adhesive resin in the heat-expandable adhesive.

[0051] The heat-expandable microspheres used in heat-expandable adhesives preferably contain a microencapsulated foaming agent. Such heat-expandable microspheres preferably contain microspheres in which a substance that readily gasifies and expands upon heating, such as isobutane, propane, or pentane, is encapsulated within an elastic shell. The material constituting the shell preferably includes one or more selected from the group consisting of vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, and polysulfone. The heat-expandable microspheres can be manufactured, for example, by coacervation or interfacial polymerization. The heat-expandable microspheres can be added to heat-expandable adhesives.

[0052] The content of at least one selected from the gas-generating component and the thermally expandable microspheres can be appropriately set according to the expansion ratio and adhesion reduction of the heat-peelable adhesive resin layer, but preferably it is 1 to 150 parts by mass, more preferably 10 to 130 parts by mass, and even more preferably 12 to 100 parts by mass, per 100 parts by mass of the adhesive resin in the heat-peelable adhesive resin layer. It is preferable to design the temperature at which the gas is generated and the temperature at which the thermally expandable microspheres expand are above 100°C.

[0053] Furthermore, if the adhesive resin layer (B) includes a layer whose adhesive strength decreases due to external stimuli, from the viewpoint of stably holding the adhesive film 50 on the support substrate 80 when peeling the electronic component 70 from the adhesive resin layer (B) by reducing the adhesive strength of the adhesive resin layer (B) by applying external stimuli, the content of at least one selected from gas-generating components and thermally expandable microspheres in the adhesive resin layer (C) is preferably 0.1% by mass or less, more preferably 0.05% by mass or less, and even more preferably 0.01% by mass or less, when the total amount of the adhesive resin layer (C) is 100% by mass, and even more preferably the adhesive resin layer (C) does not contain at least one selected from gas-generating components and thermally expandable microspheres.

[0054] The adhesive resin layer (B) preferably contains an adhesive resin (B1) from the viewpoint of further suppressing the occurrence of lifting between the support substrate 80 and the adhesive film 50. The adhesive resin (B1) preferably contains one or more selected from the group consisting of (meth)acrylic adhesive resin (b), silicone adhesive resin, urethane adhesive resin, olefin adhesive resin, and styrene adhesive resin, and more preferably contains (meth)acrylic adhesive resin (b) from the viewpoint of facilitating adjustment of adhesive strength. If the adhesive resin layer (B) includes a layer in which the adhesive strength decreases due to external stimuli, the adhesive resin (B1) is preferably included in a heat-expandable adhesive.

[0055] The (meth)acrylic adhesive resin (b) used in the adhesive resin layer (B) preferably contains as constituent units an alkyl (meth)acrylate monomer (b1) and a monomer (b2) having a functional group that can react with a crosslinking agent. In this embodiment, alkyl (meth)acrylate means alkyl acrylate, alkyl methacrylate, or a mixture thereof.

[0056] The (meth)acrylic adhesive resin (b) of this embodiment can preferably be obtained by copolymerizing a monomer mixture containing an alkyl (meth)acrylate monomer (b1) and a monomer (b2) having a functional group that can react with a crosslinking agent.

[0057] The alkyl (meth)acrylate monomer (b1) preferably includes an alkyl (meth)acrylate having an alkyl group having about 1 to 12 carbon atoms, and more preferably includes an alkyl (meth)acrylate having an alkyl group having 1 to 8 carbon atoms. The alkyl (meth)acrylate monomer (b1) preferably includes one or more selected from the group consisting of methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, and 2-ethylhexyl methacrylate. In the (meth)acrylic adhesive resin (b) according to this embodiment, the content of the alkyl (meth)acrylate monomer (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 amount of all monomer units in the (meth)acrylic adhesive resin (b) is taken as 100% by mass.

[0058] The monomer (b2) having a functional group that can react with the crosslinking agent preferably comprises one or more selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, mesaconic acid, citraconic acid, fumaric acid, maleic acid, monoalkyl itaconic acid, monoalkyl mesaconic acid, monoalkyl citraconic acid, monoalkyl fumaric acid, monoalkyl maleic acid, glycidyl acrylate, glycidyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide, methacrylamide, tert-butylaminoethyl acrylate, and tert-butylaminoethyl methacrylate, and more preferably comprises one or more selected from the group consisting of acrylic acid, methacrylic acid, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide, and methacrylamide. The content of monomers (b2) having functional groups that can react with a crosslinking agent in the (meth)acrylic adhesive resin (b) of this embodiment 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 amount of all monomer units in the (meth)acrylic adhesive resin (b) is taken as 100% by mass.

[0059] The (meth)acrylic adhesive resin (b) of this embodiment may further contain, in addition to monomers (b1) and (b2), a bifunctional monomer (b3) and a specific comonomer having surfactant properties (hereinafter referred to as a polymerizable surfactant) as constituent units. The polymerizable surfactant has the property of copolymerizing with monomers (b1), (b2), and (b3), and also acts as an emulsifier when emulsion polymerization occurs.

[0060] The bifunctional monomer (b3) is preferably 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, or a main chain structure with diacrylate or dimethacrylate at both ends and propylene It includes one or more types selected from the group consisting of glycol-type products (e.g., manufactured by Nippon Oil & Fats Co., Ltd., trade names: PDP-200, PDP-400, ADP-200, ADP-400), tetramethylene glycol-type products (e.g., manufactured by Nippon Oil & Fats Co., Ltd., trade names: ADT-250, ADT-850), and mixed types thereof (e.g., manufactured by Nippon Oil & Fats Co., Ltd., trade names: ADET-1800, ADPT-4000).

[0061] In the (meth)acrylic adhesive resin (b) of this embodiment, the content of the bifunctional monomer (b3) is preferably 0.1% by mass or more and 30% by mass or less, more preferably 0.1% by mass or more and 20% by mass or less, even more preferably 0.1% by mass or more and 15% by mass or less, and even more preferably 0.1% by mass or more and 5% by mass or less, when the total amount of all monomer units in the (meth)acrylic adhesive resin (b) is taken as 100% by mass.

[0062] The polymerizable surfactant preferably includes one or more selected from the group consisting of a polyoxyethylene nonylphenyl ether with a polymerizable 1-propenyl group introduced to the benzene ring (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.; trade names: Aqualon RN-10, RN-20, RN-30, RN-50, etc.), a polyoxyethylene nonylphenyl ether sulfate ammonium salt with a polymerizable 1-propenyl group introduced to the benzene ring (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.; trade names: Aqualon HS-10, HS-20, HS-1025, etc.), and sulfosuccinate diester surfactants 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) of this embodiment, the content of polymerizable surfactant is preferably 0.1% to 30% by mass, more preferably 0.1% to 20% by mass, even more preferably 0.1% to 15% by mass, and even more preferably 0.1% to 5% by mass, when the total amount of all monomer units in the (meth)acrylic adhesive resin (b) is taken as 100% by mass.

[0063] The (meth)acrylic adhesive resin (b) of this embodiment may further contain monomer units formed from monomers having polymerizable double bonds, such as vinyl acetate, acrylonitrile, and styrene, if necessary.

[0064] The polymerization reaction mechanism for the (meth)acrylic adhesive resin (b) of this embodiment can be radical polymerization, anionic polymerization, cationic polymerization, etc. 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 the electronic component 70, the polymerization reaction mechanism for the (meth)acrylic adhesive resin (b) of this embodiment is preferably radical polymerization. The radical polymerization initiator used when polymerization is carried out by radical polymerization is preferably benzoyl peroxide, di-t-butyl peroxide, dicumyl peroxide, 3,3,5-trimethylhexanoyl peroxide, di-2-ethylhexyl peroxydicarbonate, methyl ethyl ketone peroxide, t-butyl peroxyphthalate, t-butyl peroxybenzoate, di-t-butyl peroxyacetate, t-butyl peroxyisobutyrate, t-butyl peroxy-2-hexanoate, t-butyl peroxy-2-ethyl It comprises one or more selected from the group consisting of organic peroxides such as xanoates, 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 carried out by emulsion polymerization, among these radical polymerization initiators, water-soluble inorganic peroxides such as ammonium persulfate, potassium persulfate, and sodium persulfate, and water-soluble azo compounds having a carboxyl group in the molecule, such as 4,4'-azobis-4-cyanovaleric acid, are preferred. Considering the influence of ions on the surface of the electronic component 70, azo compounds having a carboxyl group in the molecule, such as ammonium persulfate and 4,4'-azobis-4-cyanovaleric acid, are even more preferred, and azo compounds having a carboxyl group in the molecule, such as 4,4'-azobis-4-cyanovaleric acid, are particularly preferred.

[0066] In this embodiment, the adhesive resin layer (B) preferably further comprises, in addition to the adhesive resin (B1), a crosslinking agent (B2) having two or more crosslinkable functional groups per molecule, from the viewpoint of further suppressing the occurrence of lifting between the support substrate 80 and the adhesive film 50. The crosslinking agent (B2) having two or more crosslinkable functional groups per molecule is used to react with the functional groups of the adhesive resin (B1) to adjust the adhesive strength and cohesive strength. The crosslinking agent (B2) is preferably an epoxy compound such as sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, neopentyl glycol diglycidyl ether, resolcin diglycidyl ether; an isocyanate compound such as tetramethylene diisocyanate, hexamethylene diisocyanate, trimethylolpropane toluene diisocyanate 3 adduct, polyisocyanate, diphenylmethane diisocyanate, tolylene diisocyanate; trimethylolpropane-tri-β-aziridinylpropionate, tetramethylolmethane-tri-β-aziridinylpropionate, N,N'-diphenyl The material comprises one or more compounds selected from the group consisting of aziridine compounds such as nylmethane-4,4'-bis(1-aziridinecarboxamide), N,N'-hexamethylene-1,6-bis(1-aziridinecarboxamide), N,N'-toluene-2,4-bis(1-aziridinecarboxamide), and trimethylolpropane-tri-β-(2-methylaziridine)propionate; tetrafunctional epoxy compounds such as N,N,N',N'-tetraglycidyl-m-xylenediamine and 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane; and melamine compounds such as hexamethoxymethylolmelamine, more preferably comprising one or more compounds selected from the group consisting of epoxy compounds, isocyanate compounds, and aziridine compounds.

[0067] Preferably, the amount of crosslinking agent (B2) is such that the number of functional groups in the crosslinking agent (B2) does not exceed the number of functional groups in the adhesive resin (B1). However, it may be included in excess as needed, such as when new functional groups are generated in the crosslinking reaction or when the crosslinking reaction is slow. From the viewpoint of further suppressing the occurrence of lifting between the support substrate 80 and the adhesive film 50, and from the viewpoint of improving the balance of heat resistance and adhesion performance of the adhesive resin layer (B), the amount of crosslinking agent (B2) in the adhesive resin layer (B) is preferably 0.1 parts by mass or more and 15 parts by mass or less, more preferably 0.5 parts by mass or more and 14 parts by mass or less, even more preferably 1.0 parts by mass or more and 13 parts by mass or less, even more preferably 1.5 parts by mass or more and 12 parts by mass or less, even more preferably 2.0 parts by mass or more and 11 parts by mass or less, and even more preferably 2.5 parts by mass or more and 10 parts by mass or less, per 100 parts by mass of adhesive resin (B1).

[0068] From the viewpoint of further suppressing the occurrence of lifting between the support substrate 80 and the adhesive film 50, the total content of the adhesive resin layer (B) is preferably 50% by mass or more and 100% by mass or less, more preferably 70% by mass or more and 100% by mass or less, even more preferably 90% by mass or more and 100% by mass or less, and even more preferably 95% by mass or more and 100% by mass or less, when the total content of the adhesive resin layer (B) is considered as 100% by mass.

[0069] When the adhesive resin layer (B) contains at least one selected from a gas-generating component and thermally expandable microspheres, the total content of the adhesive resin (B1), crosslinking agent (B2), and at least one selected from the gas-generating component and thermally expandable microspheres in the adhesive resin layer (B) is preferably 50% by mass or more and 100% by mass or less, more preferably 70% by mass or more and 100% by mass or less, even more preferably 90% by mass or more and 100% by mass or less, and even more preferably 95% by mass or more and 100% by mass or less, when the total content of the adhesive resin layer (B) is 100% by mass.

[0070] From the viewpoint of further suppressing the occurrence of lifting between the support substrate 80 and the adhesive film 50, the thickness of the adhesive resin layer (B) is preferably 1 μm to 500 μm, more preferably 3 μm to 300 μm, even more preferably 5 μm to 100 μm, and even more preferably 10 μm to 50 μm.

[0071] The adhesive resin layer (B) can be formed, for example, by applying an adhesive coating liquid onto a substrate layer (A), or by transferring an adhesive resin layer (B) formed on a separator onto the substrate layer (A). Conventional coating methods such as the roll coater method, reverse roll coater method, gravure roll method, bar coat method, comma coater method, and die coater method can be used for applying the adhesive coating liquid. There are no particular restrictions on the drying conditions of the applied adhesive coating liquid, but the drying temperature is preferably 60°C to 200°C, more preferably 65°C to 170°C, and even more preferably 65°C to 150°C, and the drying time is preferably 10 seconds to 10 minutes, more preferably 15 seconds to 5 minutes. In order to sufficiently promote the crosslinking reaction between the adhesive resin (B1) and the crosslinking agent (B2), the adhesive coating liquid may be heated for approximately 5 to 300 hours in a temperature range of 40°C to 80°C after drying is complete. Furthermore, the base material layer (A) and the adhesive resin layer (B) may be formed by co-extrusion molding, or the film-like base material layer (A) and the film-like adhesive resin layer (B) may be formed by lamination (stacking). Also, if the adhesive film 50 of this embodiment includes an intermediate layer (D) described later, the adhesive resin layer (B) may be formed, for example, by applying an adhesive coating liquid onto the intermediate layer (D), or by transferring an adhesive resin layer (B) formed on a separator onto the intermediate layer (D), or the base material layer (A) and intermediate layer (D) and the adhesive resin layer (B) may be formed by co-extrusion molding, or the film-like base material layer (A) and intermediate layer (D) and the film-like adhesive resin layer (B) may be formed by lamination (stacking).

[0072] [Adhesive resin layer (C)] The adhesive film 50 of this embodiment is provided with an adhesive resin layer (C) on the surface of the base layer (A) that is opposite to the surface on which the adhesive resin layer (B) is provided. The adhesive resin layer (C) is, for example, a layer that contacts the surface of the support substrate 80 to temporarily fix the adhesive film 50 onto the support substrate 80.

[0073] As described above, the adhesive film 50 of this embodiment preferably includes at least one of the adhesive resin layers (B) and adhesive resin layers (C) in which the adhesive strength decreases due to external stimuli. The adhesive film 50 of this embodiment preferably includes one or more selected from the group consisting of heat-peelable adhesive resin layers and light-peelable adhesive resin layers, and more preferably includes a heat-peelable adhesive resin layer. The heat-peelable adhesive resin layer can be the one described in [Adhesive resin layer (B)] above.

[0074] Furthermore, if the adhesive resin layer (C) includes a layer whose adhesive strength decreases due to external stimuli, from the viewpoint of stably holding the electronic component 70 on the adhesive resin layer (B) when the adhesive strength of the adhesive resin layer (C) is reduced by applying external stimuli and the support substrate 80 is peeled off from the adhesive resin layer (C), the content of at least one selected from gas-generating components and thermally expandable microspheres in the adhesive resin layer (B) is preferably 0.1% by mass or less, more preferably 0.05% by mass or less, and even more preferably 0.01% by mass or less, when the total amount of the adhesive resin layer (B) is 100% by mass, and even more preferably the adhesive resin layer (B) does not contain at least one selected from gas-generating components and thermally expandable microspheres.

[0075] The adhesive resin (C1) constituting the adhesive resin layer (C) preferably comprises one or more selected from the group consisting of (meth)acrylic adhesive resin (c), urethane adhesive resin, silicone adhesive resin, polyolefin adhesive resin, polyester adhesive resin, polyamide adhesive resin, fluorine adhesive resin, and styrene-diene block copolymer adhesive resin, and more preferably comprises (meth)acrylic adhesive resin (c). If the adhesive resin layer (C) includes a layer in which the adhesive strength decreases due to external stimuli, the adhesive resin (C1) is preferably included in a heat-expandable adhesive.

[0076] The (meth)acrylic adhesive resin (c) used in the adhesive resin layer (C) preferably comprises an alkyl (meth)acrylate monomer (c1) and a monomer (c2) having a functional group that can react with a crosslinking agent as constituent units.

[0077] The (meth)acrylic adhesive resin (c) of this embodiment can preferably be obtained by copolymerizing a monomer mixture containing an alkyl (meth)acrylate monomer (c1) and a monomer (c2) having a functional group that can react with a crosslinking agent.

[0078] The alkyl (meth)acrylate monomer (c1) preferably includes an alkyl (meth)acrylate having an alkyl group having about 1 to 12 carbon atoms, and more preferably includes an alkyl (meth)acrylate having an alkyl group having 1 to 8 carbon atoms. The alkyl (meth)acrylate monomer (c1) preferably includes one or more selected from the group consisting of methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, and 2-ethylhexyl methacrylate. In the (meth)acrylic adhesive resin (c) according to this embodiment, the content of alkyl (meth)acrylate monomer (c1) 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 amount of all monomer units in the (meth)acrylic adhesive resin (c) is taken as 100% by mass.

[0079] The monomer (c2) having a functional group that can react with the crosslinking agent preferably comprises one or more selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, mesaconic acid, citraconic acid, fumaric acid, maleic acid, monoalkyl itaconic acid, monoalkyl mesaconic acid, monoalkyl citraconic acid, monoalkyl fumaric acid, monoalkyl maleic acid, glycidyl acrylate, glycidyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide, methacrylamide, tert-butylaminoethyl acrylate, and tert-butylaminoethyl methacrylate, and more preferably comprises one or more selected from the group consisting of acrylic acid, methacrylic acid, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide, and methacrylamide. The content of monomers (c2) having functional groups that can react with a crosslinking agent in the (meth)acrylic adhesive resin (c) of this embodiment 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 amount of all monomer units in the (meth)acrylic adhesive resin (c) is taken as 100% by mass.

[0080] The (meth)acrylic adhesive resin (c) of this embodiment may further contain, in addition to monomers (c1) and monomer (c2), a bifunctional monomer (c3) and a specific comonomer having surfactant properties (hereinafter referred to as a polymerizable surfactant) as constituent units. The polymerizable surfactant has the property of copolymerizing with monomers (c1), monomer (c2), and monomer (c3), and also acts as an emulsifier when emulsion polymerization occurs.

[0081] The bifunctional monomer (c3) is preferably 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, or a main chain structure of propylene with diacrylate or dimethacrylate at both ends. It includes one or more types selected from the group consisting of glycol-type products (e.g., manufactured by Nippon Oil & Fats Co., Ltd., trade names: PDP-200, PDP-400, ADP-200, ADP-400), tetramethylene glycol-type products (e.g., manufactured by Nippon Oil & Fats Co., Ltd., trade names: ADT-250, ADT-850), and mixed types thereof (e.g., manufactured by Nippon Oil & Fats Co., Ltd., trade names: ADET-1800, ADPT-4000).

[0082] In the (meth)acrylic adhesive resin (c) of this embodiment, the content of the bifunctional monomer (c3) is preferably 0.1% by mass or more and 30% by mass or less, more preferably 0.1% by mass or more and 20% by mass or less, even more preferably 0.1% by mass or more and 15% by mass or less, and even more preferably 0.1% by mass or more and 5% by mass or less, when the total amount of all monomer units in the (meth)acrylic adhesive resin (c) is taken as 100% by mass.

[0083] The polymerizable surfactant preferably includes one or more selected from the group consisting of a polyoxyethylene nonylphenyl ether with a polymerizable 1-propenyl group introduced to the benzene ring (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.; trade names: Aqualon RN-10, RN-20, RN-30, RN-50, etc.), a polyoxyethylene nonylphenyl ether sulfate ammonium salt with a polymerizable 1-propenyl group introduced to the benzene ring (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.; trade names: Aqualon HS-10, HS-20, HS-1025, etc.), and sulfosuccinate diester surfactants 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 (c) of this embodiment, the content of polymerizable surfactant is preferably 0.1% to 30% by mass, more preferably 0.1% to 20% by mass, even more preferably 0.1% to 15% by mass, and even more preferably 0.1% to 5% by mass, when the total amount of all monomer units in the (meth)acrylic adhesive resin (c) is taken as 100% by mass.

[0084] The (meth)acrylic adhesive resin (c) of this embodiment may further contain monomer units formed from monomers having polymerizable double bonds, such as vinyl acetate, acrylonitrile, and styrene, if necessary.

[0085] The polymerization reaction mechanism for the (meth)acrylic adhesive resin (c) of this embodiment can be radical polymerization, anionic polymerization, cationic polymerization, etc. Considering the manufacturing cost of the (meth)acrylic adhesive resin (c), the influence of the functional groups of the monomer, and the influence of ions on the surface of the electronic component 70, the polymerization reaction mechanism for the (meth)acrylic adhesive resin (c) of this embodiment is preferably radical polymerization. The radical polymerization initiator used when polymerization is carried out by radical polymerization is preferably benzoyl peroxide, di-t-butyl peroxide, dicumyl peroxide, 3,3,5-trimethylhexanoyl peroxide, di-2-ethylhexyl peroxydicarbonate, methyl ethyl ketone peroxide, t-butyl peroxyphthalate, t-butyl peroxybenzoate, di-t-butyl peroxyacetate, t-butyl peroxyisobutyrate, t-butyl peroxy-2-hexanoate, t-butyl peroxy-2-ethyl It comprises one or more selected from the group consisting of organic peroxides such as xanoates, 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.

[0086] When polymerization is carried out by emulsion polymerization, among these radical polymerization initiators, water-soluble inorganic peroxides such as ammonium persulfate, potassium persulfate, and sodium persulfate, and water-soluble azo compounds having a carboxyl group in the molecule, such as 4,4'-azobis-4-cyanovaleric acid, are preferred. Considering the influence of ions on the surface of the electronic component 70, azo compounds having a carboxyl group in the molecule, such as ammonium persulfate and 4,4'-azobis-4-cyanovaleric acid, are even more preferred, and azo compounds having a carboxyl group in the molecule, such as 4,4'-azobis-4-cyanovaleric acid, are particularly preferred.

[0087] In this embodiment, the adhesive resin layer (C) preferably further comprises, in addition to the adhesive resin (C1), a crosslinking agent (C2) having two or more crosslinkable functional groups per molecule, from the viewpoint of further suppressing the occurrence of lifting between the support substrate 80 and the adhesive film 50. The crosslinking agent (C2) having two or more crosslinkable functional groups per molecule is used to react with the functional groups of the adhesive resin (C1) to adjust the adhesive strength and cohesive strength. The crosslinking agent (C2) is preferably an epoxy compound such as sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, neopentyl glycol diglycidyl ether, or resolcin diglycidyl ether; an isocyanate compound such as tetramethylene diisocyanate, hexamethylene diisocyanate, trimethylolpropane toluene diisocyanate 3 adduct, polyisocyanate, diphenylmethane diisocyanate, or tolylene diisocyanate; or trimethylolpropane-tri-β-aziridinylpropionate, tetramethylolmethane-tri-β-aziridinylpropionate, or N,N'-diphenyl The material comprises one or more compounds selected from the group consisting of aziridine compounds such as nylmethane-4,4'-bis(1-aziridinecarboxamide), N,N'-hexamethylene-1,6-bis(1-aziridinecarboxamide), N,N'-toluene-2,4-bis(1-aziridinecarboxamide), and trimethylolpropane-tri-β-(2-methylaziridine)propionate; tetrafunctional epoxy compounds such as N,N,N',N'-tetraglycidyl-m-xylenediamine and 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane; and melamine compounds such as hexamethoxymethylolmelamine, more preferably comprising one or more compounds selected from the group consisting of epoxy compounds, isocyanate compounds, and aziridine compounds.

[0088] Preferably, the amount of crosslinking agent (C2) is such that the number of functional groups in the crosslinking agent (C2) does not exceed the number of functional groups in the adhesive resin (C1). However, it may be included in excess as needed, such as when new functional groups are generated in the crosslinking reaction or when the crosslinking reaction is slow. From the viewpoint of further suppressing the occurrence of lifting between the support substrate 80 and the adhesive film 50, and from the viewpoint of improving the balance of heat resistance and adhesion performance of the adhesive resin layer (C), the amount of crosslinking agent (C2) in the adhesive resin layer (C) is preferably 0.1 parts by mass to 15 parts by mass, more preferably 0.5 parts by mass to 10 parts by mass, even more preferably 1.0 part by mass to 5 parts by mass, and even more preferably 1.5 parts by mass to 3 parts by mass per 100 parts by mass of adhesive resin (C1).

[0089] From the viewpoint of further suppressing the occurrence of lifting between the support substrate 80 and the adhesive film 50, the total content of the adhesive resin layer (C) is preferably 50% to 100% by mass, more preferably 70% to 100% by mass, even more preferably 90% to 100% by mass, and even more preferably 95% to 100% by mass, when the total content of the adhesive resin layer (C) is considered to be 100% by mass.

[0090] When the adhesive resin layer (C) contains at least one selected from a gas-generating component and thermally expandable microspheres, the total content of the adhesive resin (C1), crosslinking agent (C2), and at least one selected from the gas-generating component and thermally expandable microspheres in the adhesive resin layer (C) is preferably 50% by mass or more and 100% by mass or less, more preferably 70% by mass or more and 100% by mass or less, even more preferably 90% by mass or more and 100% by mass or less, and even more preferably 95% by mass or more and 100% by mass or less, when the total content of the adhesive resin layer (C) is considered as 100% by mass.

[0091] The adhesive resin layer (C) according to this embodiment preferably further contains a tackifying resin in addition to the adhesive resin (C1) from the viewpoint of improving adhesion to the support substrate 80. By including a tackifying resin in the adhesive resin layer (C), it becomes easier to adjust the adhesion to the support substrate 80 at or near room temperature. The tackifying resin preferably has a softening point of 100°C or higher. The tackifying resin includes one or more selected from the group consisting of 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 resins; petroleum resins obtained by hydrogenating, disproportionating, polymerizing, or maleinating these natural rosins; and coumarone-indene resins.

[0092] The softening point of the tackifying resin is preferably 100°C or higher, more preferably 100°C to 160°C, and even more preferably 120°C to 150°C. Using a tackifying resin with a softening point within the above range not only reduces contamination and adhesive residue on the support substrate 80, but also further improves adhesion to the support substrate 80 in the working environment. Furthermore, using a tackifying resin containing a rosin-based resin not only reduces contamination and adhesive residue on the support substrate 80, but also improves the adhesion of the adhesive film 50 to the support substrate 80 in an environment of 80 to 130°C, and after the thermally expandable microspheres expand, the adhesive film 50 can be peeled off the support substrate 80 even more easily.

[0093] The content of the tackifying resin can be appropriately selected so as to adjust the elastic modulus of the adhesive resin layer (C) to a desired predetermined numerical range, and there are no particular restrictions. From the viewpoint of balancing the performance of the elastic modulus of the adhesive resin layer (C) and the initial peeling force, the content of the tackifying resin is preferably 1 to 100 parts by mass per 100 parts by mass of the adhesive resin (C1), and more preferably 2 to 50 parts by mass from the viewpoint of balancing the performance of adhesion to the support substrate 80 and adhesiveness at room temperature. When the content of the tackifying resin is above the lower limit per 100 parts by mass of the adhesive resin (C1), adhesion to the support substrate 80 during work tends to be good. On the other hand, when it is below the upper limit, adhesiveness to the support substrate 80 at room temperature tends to be good. Furthermore, the acid value of the tackifying resin is preferably 30 or less. When the acid value of the tackifying resin is below the upper limit, adhesive residue tends to be less likely to be left on the support substrate 80 when peeled off.

[0094] From the viewpoint of further suppressing the occurrence of lifting between the support substrate 80 and the adhesive film 50, the thickness of the adhesive resin layer (C) is preferably 1 μm to 500 μm, more preferably 5 μm to 300 μm, even more preferably 10 μm to 150 μm, even more preferably 15 μm to 100 μm, and even more preferably 20 μm to 70 μm.

[0095] The adhesive resin layer (C) can be formed, for example, by applying an adhesive coating liquid onto a substrate layer (A), or by transferring an adhesive resin layer (C) formed on a separator onto the substrate layer (A). Conventional known coating methods such as the roll coater method, reverse roll coater method, gravure roll method, bar coat method, comma coater method, and die coater method can be used for applying the adhesive coating liquid. There are no particular restrictions on the drying conditions of the applied adhesive coating liquid, but the drying temperature is preferably 60°C to 200°C, more preferably 65°C to 170°C, and even more preferably 65°C to 150°C, and the drying time is preferably 10 seconds to 10 minutes, more preferably 15 seconds to 5 minutes. In order to sufficiently promote the crosslinking reaction between the adhesive resin (C1) and the crosslinking agent (C2), the adhesive coating liquid may be heated for about 5 hours to 300 hours in a temperature range of 40°C to 80°C after drying is complete. Furthermore, the base material layer (A) and the adhesive resin layer (C) may be formed by co-extrusion molding, or by laminating (stacking) a film-like base material layer (A) and a film-like adhesive resin layer (C). Also, if the adhesive film 50 of this embodiment includes an intermediate layer (D) described later, the adhesive resin layer (C) may be formed, for example, by applying an adhesive coating liquid onto the intermediate layer (D), or by transferring an adhesive resin layer (C) formed on a separator onto the intermediate layer (D), or by co-extrusion molding of the base material layer (A) and intermediate layer (D) and the adhesive resin layer (C), or by laminating (stacking) a film-like base material layer (A) and intermediate layer (D) and the film-like adhesive resin layer (C).

[0096] [Intermediate layer (D)] As shown in Figure 2, the adhesive film 50 of this embodiment preferably further includes an intermediate layer (D) between the base material layer (A) and the adhesive resin layer (B), and between the base material layer (A) and the adhesive resin layer (C), from the viewpoint of further suppressing the occurrence of lifting between the support substrate 80 and the adhesive film 50. Figure 2 shows an embodiment in which the adhesive film 50 of this embodiment further includes an intermediate layer (D) between the base material layer (A) and the adhesive resin layer (B).

[0097] The intermediate layer (D) preferably includes a layer that hardens upon external stimulation, from the viewpoint of further suppressing the occurrence of lifting between the support substrate 80 and the adhesive film 50.

[0098] The resin constituting the intermediate layer (D) preferably comprises one or more selected from the group consisting of (meth)acrylic resins, urethane resins, silicone resins, polyolefin resins, polyester resins, polyamide resins, fluororesins, and styrene-diene block copolymer resins, more preferably comprising one or more selected from the group consisting of (meth)acrylic resins and polyolefin resins, and even more preferably comprising a (meth)acrylic resin.

[0099] The intermediate layer (D) preferably contains a crosslinking agent, from the viewpoint of further suppressing the occurrence of lifting between the support substrate 80 and the adhesive film 50. Examples of crosslinking agents used in the intermediate layer (D) of this embodiment include those that undergo a crosslinking reaction by chemical species generated from the initiator. The crosslinking agent used in the intermediate layer (D) of this embodiment preferably contains one or more selected from the group consisting of polyfunctional (meth)acrylate compounds and isocyanate compounds, from the viewpoint of further suppressing the occurrence of lifting between the support substrate 80 and the adhesive film 50.

[0100] The amount of crosslinking agent in the intermediate layer (D) is preferably within a range such that the number of functional groups in the crosslinking agent does not exceed the number of functional groups in the adhesive resin. However, it may be included in excess as needed, such as when new functional groups are generated in the crosslinking reaction or when the crosslinking reaction is slow. The amount of crosslinking agent in the intermediate layer (D) 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 resin in the intermediate layer (D).

[0101] The total content of resin and crosslinking agent in the intermediate layer (D) is preferably 50% by mass or more and 100% by mass or less, more preferably 70% by mass or more and 100% by mass or less, even more preferably 90% by mass or more and 100% by mass or less, and even more preferably 95% by mass or more and 100% by mass or less, when the entire intermediate layer (D) is considered to be 100% by mass.

[0102] The intermediate layer (D) preferably contains an initiator. The initiator preferably contains one or more selected from the group consisting of a thermal initiator that generates an activated species by heat and a photoinitiator that generates an activated species by light.

[0103] The thermal initiator is not particularly limited, as long as it is capable of crosslinking the resin and / or crosslinking agent in the intermediate layer (D) by thermal energy. The chemical species generated from the thermal initiator may be appropriately selected based on the functional groups of the resin and / or crosslinking agent. The chemical species generated from the thermal initiator are typically radicals or cations.

[0104] From the viewpoint of further suppressing the occurrence of lifting between the support substrate 80 and the adhesive film 50, the thermal initiator preferably comprises one or more selected from the group consisting of aromatic ketones, onium salt compounds, organic peroxides, thio compounds, hexaarylbiimidazole compounds, ketoxime ester compounds, borate compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having carbon-halogen bonds, and azo compounds. From the viewpoint of availability and ease of handling, it more preferably comprises one or more selected from the group consisting of azo compounds or organic peroxides, and even more preferably comprises organic peroxides.

[0105] Commercially available thermal initiators include V-70, V-65, V-601, V-59, V-40, VF-096, V-30, VAm-110, VAm-111 (all manufactured by Fujifilm Wako Pure Chemical Industries), Niper BW, Niper BMT, Perloyl TCP, Perloyl L, Perloyl 355, Perloyl SA, Perhexa HC, Perbutyl 355, Perbutyl D, Perbutyl L, Perbutyl ND, Perocta O, Perhexyl D, Perhexyl O, Perhexyl PV (all manufactured by NOF Corporation), Trigonox 36-C75, Laurox, Percadox L-W75, Percadox CH-50L, Trigonox TMBH, Kayakumen H, Kayabutyl H-70, Percadox BC-FF, Kayahex Examples include SA AD, Percadox 14, Kayabutyl C, Kayabutyl D, Percadox 12-XL25, Trigonox 22-N70 (22-70E), Trigonox D-T50, Trigonox 423-C70, Kayaester CND-C70, Trigonox 23-C70, Trigonox 257-C70, Kayaester P-70, Kayaester TMPO-70, Trigonox 121, Kayaester O, Kayaester HTP-65W, Kayaester AN, Trigonox 42, Trigonox F-C50, Kayabutyl B, Kayacarbon EH, Kayacarbon I-20, Kayacarbon BIC-75, Trigonox 117, Kayaren 6-70 (all manufactured by Kayaku Akzo).

[0106] From the viewpoint of further suppressing the occurrence of lifting between the support substrate 80 and the adhesive film 50, the content of the thermal initiator is preferably 0.1 parts by mass to 7 parts by mass, more preferably 0.3 parts by mass to 7 parts by mass, and even more preferably 0.5 parts by mass to 3 parts by mass, per 100 parts by mass of resin in the intermediate layer (D).

[0107] The photoinitiator is not particularly limited, as long as it is capable of crosslinking the resin and / or crosslinking agent in the intermediate layer (D) by light energy. The chemical species generated from the photoinitiator may be appropriately selected based on the functional groups of the resin and / or crosslinking agent. The chemical species generated from the photoinitiator are typically radicals or cations.

[0108] From the viewpoint of further suppressing the occurrence of lifting between the support substrate 80 and the adhesive film 50, the photoinitiator preferably comprises one or more selected from the group consisting of alkylphenone-based photoinitiators, acetophenone-based photoinitiators, oxime ester-based photoinitiators, benzoin ether-based photoinitiators, acylphosphine oxide-based photoinitiators, α-ketol-based photoinitiators, aromatic sulfonyl chloride-based photoinitiators, photoactive oxime-based photoinitiators, benzoin-based photoinitiators, benzyl-based photoinitiators, benzophenone-based photoinitiators, and thioxanthone-based photoinitiators, and more preferably comprises alkylphenone-based photoinitiators from the viewpoint of high reactivity and low sublimation.

[0109] The alkylphenone-based photoinitiator preferably comprises one or more selected from the group consisting of 2-benzyl-2-(dimethylamino)-4'-morpholinobtyrophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexylphenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-propan-1-one, and 2-hydroxy-1-{[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one. The acetophenone-based photoinitiator preferably comprises one or more selected from the group consisting of 1-hydroxycyclohexyl-phenyl-ketone, 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, and methoxyacetophenone. The oxime ester-based photoinitiator preferably comprises one or more selected from the group consisting of 1,2-octanedione, 1-[4-(phenylthio)phenyl]-2-(o-benzoyloxime)ethanone, and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-1-(o-acetyloxime). The benzoin ether-based photoinitiator preferably comprises one or more selected from the group consisting of benzoin ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, and benzoin isobutyl ether, and substituted benzoin ethers such as anisole methyl ether.Acylphosphine oxide photoinitiators preferably comprise one or more selected from the group consisting of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2,4-di-n-butoxyphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide. Alpha-ketol photoinitiators preferably comprise one or more selected from the group consisting of 2-methyl-2-hydroxypropiophenone and 1-[4-(2-hydroxyethyl)phenyl]-2-methylpropan-1-one. Aromatic sulfonyl chloride photoinitiators preferably comprise 2-naphthalenesulfonyl chloride. Photoactive oxime photoinitiators preferably comprise 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime. Benzoin-based photoinitiators preferably contain benzoin. Benzyl-based photoinitiators preferably contain benzyl. Benzophenone-based photoinitiators preferably contain one or more selected from the group consisting of benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, and α-hydroxycyclohexylphenyl ketone. Thioxanthone-based photoinitiators preferably contain one or more selected from the group consisting of thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, and dodecylthioxanthone.

[0110] Preferably, a photoinitiator that absorbs light with a wavelength of 300 nm or more (for example, light with a wavelength of 300 nm to 500 nm) and generates radicals can be used. The photoinitiator can be used alone or in appropriate combinations of two or more types.

[0111] From the viewpoint of further suppressing the occurrence of lifting between the support substrate 80 and the adhesive film 50, the amount of photoinitiator is preferably 0.1 parts by mass to 7 parts by mass, more preferably 0.3 parts by mass to 7 parts by mass, and even more preferably 0.5 parts by mass to 3 parts by mass, per 100 parts by mass of resin in the intermediate layer (D).

[0112] The intermediate layer (D) may be a single layer or a multilayer layer. From the viewpoint of further suppressing the occurrence of lifting between the support substrate 80 and the adhesive film 50, the thickness of the intermediate layer (D) is preferably 5 μm to 1000 μm, more preferably 10 μm to 500 μm, and even more preferably 15 μm to 300 μm.

[0113] The intermediate layer (D) can be formed, for example, by applying an intermediate layer forming coating solution onto the base layer (A), or by transferring an intermediate layer (D) formed on a separator onto the base layer (A). Conventional coating methods such as the roll coater method, reverse roll coater method, gravure roll method, bar coat method, comma coater method, and die coater method can be used for applying the intermediate layer forming coating solution. There are no particular restrictions on the drying conditions of the applied intermediate layer forming coating solution, but the drying temperature is preferably 60°C to 200°C, more preferably 65°C to 170°C, and even more preferably 65°C to 150°C. The drying time is preferably 10 seconds to 10 minutes, more preferably 15 seconds to 5 minutes. In order to sufficiently promote the crosslinking reaction in the intermediate layer forming coating solution, after the drying of the intermediate layer forming coating solution is completed, it may be heated in a temperature range of 40°C to 80°C for about 5 hours to 300 hours. Furthermore, the base layer (A) and the intermediate layer (D) may be formed by co-extrusion molding, or they may be formed by laminating (layering) a film-like base layer (A) and a film-like intermediate layer (D).

[0114] [Other Layers] The adhesive film 50 according to this embodiment may further have layers such as an unevenness-absorbing layer, an impact-absorbing layer, or an easy-adhesion layer between the base layer (A) and the adhesive resin layer (B) or between the base layer (A) and the adhesive resin layer (C), to the extent that it does not impair the effects of this embodiment.

[0115] The embodiments of the present invention have been described above, but these are merely examples, and various other configurations can also be adopted.

[0116] It should be noted that the present invention is not limited to the embodiments described above, and any modifications, improvements, etc., that can achieve the objectives of the present invention are included in the present invention.

[0117] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited thereto.

[0118] The details of the method for producing the adhesive film are as follows.

[0119] <Adhesive Resin Solution SB1> To deionized pure water, 0.5 parts by mass of 4,4'-azobis-4-cyanovaleric acid (manufactured by Otsuka Chemical Co., Ltd., trade name: ACVA) was added as a polymerization initiator, 74.3 parts by mass of n-butyl acrylate and 13.7 parts by mass of methyl methacrylate as monomer (b1), 9 parts by mass of 2-hydroxyethyl methacrylate as monomer (b2), and 3 parts by mass of a polymerizable surfactant, which is an ammonium salt of the sulfate ester of polyoxyethylene nonylphenyl ether with a polymerizable 1-propenyl group introduced to the benzene ring (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.; trade name: Aqualon HS-1025). Emulsification polymerization was carried out at 70-72°C for 8 hours under stirring to obtain an acrylic resin emulsion. This was neutralized with ammonia water (pH = 7.0) to obtain adhesive resin solution SB1 with a solid content concentration of 42.5%.

[0120] <Adhesive Resin Solution SB2> In deionized pure water, 0.5 parts by mass of ammonium persulfate was added 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 (b1), 3 parts by mass of 2-hydroxyethyl methacrylate as monomer (b2), 1 part by mass of polytetramethylene glycol diacrylate (manufactured by Nippon Oil & Fats Co., Ltd., trade name: ADT-250) as monomer (b3), and 2 parts by mass of a polymerizable surfactant, which is an ammonium salt of the sulfate ester of polyoxyethylene nonylphenyl ether with a polymerizable 1-propenyl group introduced to the benzene ring (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon HS-1025). Emulsification polymerization was carried out at 70-72°C for 8 hours under stirring to obtain an acrylic resin emulsion. This was neutralized with ammonia water (pH = 7.0) to obtain a sticky resin solution SB2 with a solid content concentration of 56.5%.

[0121] <Adhesive Coating Solution B1> Adhesive coating solution B1 was obtained by mixing 57.4 parts by mass of adhesive resin solution SB1, 42.6 parts by mass of adhesive resin solution SB2, 0.4 parts by mass of dimethylethanolamine, and 3.4 parts by mass of an epoxy compound (manufactured by Nagase ChemteX, Ex-1610), which is a crosslinking agent.

[0122] <Adhesive Resin Solution SC1> In a mixed solvent containing ethyl acetate and toluene, 0.536 parts by mass of t-butylperoxy-2-ethylhexanoate (manufactured by Nippon Oil & Fats Co., Ltd., trade name: Perbutyl O (registered trademark)) was added as a polymerization initiator, 34.9 parts by mass of 2-ethylhexyl acrylate, 41 parts by mass of n-butyl acrylate, and 14.7 parts by mass of ethyl acrylate were added as monomers (c1), and 9.4 parts by mass of 2-hydroxyethyl methacrylate was added as monomer (c2). Solution polymerization was carried out at 83-87°C for 11 hours under stirring to obtain an acrylic resin solution with a solid content of 45% by mass. This was designated as adhesive resin solution SC1.

[0123] <Adhesive Coating Solution C1> 100 parts by mass of adhesive resin solution SC1 and 0.9 parts by mass of an isocyanate compound (manufactured by Mitsui Chemicals, Inc., trade name: Olestar P49-75S) as a crosslinking agent (2 parts by mass per 100 parts by mass of adhesive resin) were mixed, and the solid content concentration was adjusted to 40% with ethyl acetate to obtain adhesive coating solution C1.

[0124] <Adhesive Coating Solution C2> Adhesive coating solution C2 was prepared by mixing 100 parts by mass of adhesive resin solution SC1, 2.25 parts by mass of polymerized rosin ester tackifier (manufactured by Arakawa Chemical Industries, Ltd., trade name: Pencel D-125) (5 parts by mass per 100 parts by mass of adhesive resin), 1.2 parts by mass of isocyanate compound (manufactured by Mitsui Chemicals, Inc., trade name: Olestar P49-75S) as a crosslinking agent (2.67 parts by mass per 100 parts by mass of adhesive resin), and 6.75 parts by mass of thermally expandable microspheres (manufactured by Sekisui Chemical Co., Ltd., trade name: Advancell EM-503) (15 parts by mass per 100 parts by mass of adhesive resin), and adjusting the solid content concentration to 30% with ethyl acetate.

[0125] [Example 1] Adhesive coating liquid B1 was applied to a polyethylene terephthalate (PET) film (38 μm thick), which was the base layer, and then dried at 120°C for 2 minutes to form an adhesive resin layer (B) with a thickness of 10 μm. Next, adhesive coating liquid C1 was applied to a separator with a thickness of 31 μm, separate from the base layer, and dried at 120°C for 2 minutes to obtain a resin film (D). The side of this resin film (D) that was not in contact with the separator was attached to the surface of the PET film opposite to the adhesive resin layer (B) to form an intermediate layer (D) with a thickness of 20 μm. Then, adhesive coating liquid C2 was applied to another separator with a thickness of 31 μm, and dried at 120°C for 2 minutes to obtain an adhesive resin film (C). After peeling off the separator on the intermediate layer (D), the non-contacting side of the adhesive resin film (C) was attached to the surface of the intermediate layer (D) from which the separator had been peeled off, forming a heat-peelable adhesive resin layer (C) with a thickness of 30 μm, thereby obtaining an adhesive film. Note that the adhesive resin layer (C) contains thermally expandable microspheres, so its adhesive strength decreases when external stimuli such as heat treatment are applied. Next, after peeling off the separator on the adhesive resin layer (C) side of the obtained adhesive film, the adhesive resin layer (C) side was bonded to a glass substrate with a diameter of 300 mm. Subsequently, the adhesive film and the glass substrate were heat-treated under the conditions of heating temperature: 130°C and heating time: 60 minutes to reduce the amount of volatile components in the adhesive film. Next, a silicon wafer with a diameter of 200 mm and a thickness of 750 μm, which is a dummy wafer for a power device wafer to be back-ground and subjected to back metal treatment as an electronic component, was placed on the adhesive resin layer (B) of the adhesive film and adhered to it. Next, the adhesive strength of the adhesive resin layer (B) and the adhesive resin layer (C) was stabilized by heat treatment under the conditions of heating temperature: 130°C and heating time: 30 minutes, thereby obtaining the electronic device 1. Furthermore, even when the heating temperature used to reduce the amount of volatile components in the adhesive film by heat treatment of the adhesive film and the glass substrate was set to 100°C and 150°C, the same results as in Example 1 were obtained in both cases.

[0126] [Comparative Example 1] An electronic device 2 was obtained in the same manner as in Example 1, except that the adhesive film and the glass substrate were not heat-treated under the conditions of heating temperature: 130°C and heating time: 60 minutes.

[0127] [Comparative Example 2] First, an adhesive film was obtained in the same manner as in Example 1. Next, the adhesive resin layer (C) side of the obtained adhesive film was bonded to a glass substrate with a diameter of 300 mm. Then, a silicon wafer with a diameter of 200 mm and a thickness of 750 μm, which is a dummy wafer for a power device wafer to be back-ground and back-metal treated as an electronic component, was placed on the adhesive resin layer (B) of the adhesive film and made to adhere tightly. Next, the adhesive strength of the adhesive resin layer (B) and the adhesive resin layer (C) was stabilized by heat treatment at 130°C for 30 minutes, and a structure was obtained. After that, this structure was left to stand in a clean room at a temperature of 25°C and a humidity of 65% for one week to allow it to absorb moisture again and reach an equilibrium state. The structure thus obtained was heat-treated under the conditions of heating temperature: 130°C and heating time: 60 minutes to reduce the amount of volatile components in the structure and obtain an electronic device 3.

[0128] <Evaluation> (Lifting between the support substrate and the adhesive film) For electronic devices 1 to 3 obtained in the examples and each comparative example, the lifting between the glass substrate and the adhesive film was confirmed by visual inspection from the glass substrate side and evaluated according to the following criteria. The results are shown in Table 1. A: No lifting occurred between the support substrate and the adhesive film. B: Lifting occurred between the support substrate and the adhesive film.

[0129]

[0130] As shown in the example, it can be seen that the occurrence of lifting between the support substrate and the adhesive film can be suppressed by reducing the amount of volatile components in the adhesive film after bonding the support substrate and the adhesive film together.

[0131] This application claims priority based on Japanese Patent Application No. 2024-229913, filed on 26 December 2024, and incorporates all of its disclosures herein.

[0132] A Substrate layer (A) B Adhesive resin layer (B) C Adhesive resin layer (C) D Intermediate layer (D) 50 Adhesive film 60 Metal layer 70 Electronic component 80 Support substrate 100 Structure 200 Electronic device

Claims

1. A method for manufacturing an electronic device, comprising the steps of: preparing an adhesive film containing an adhesive resin layer (B), a substrate layer (A), and an adhesive resin layer (C) in that order; then attaching a support substrate to the adhesive resin layer (C) side of the adhesive film; reducing the amount of volatile components in the adhesive film; attaching an electronic component to the adhesive resin layer (B) side of the adhesive film; backgrinding the electronic component; and forming a metal layer on the backgrinded surface of the electronic component, in that order.

2. The method for manufacturing an electronic device according to claim 1, wherein the step of reducing the amount of volatile components in the adhesive film includes a step of reducing the amount of volatile components in the adhesive film by heat treatment.

3. The method for manufacturing an electronic device according to claim 2, wherein the heating time in the step of reducing the amount of volatile components in the adhesive film by the heat treatment is 0.1 hours or more and 48 hours or less.

4. The method for manufacturing an electronic device according to claim 2 or 3, wherein the heating temperature in the step of reducing the amount of volatile components in the adhesive film by the heat treatment is 100°C or more and 150°C or less.

5. A method for manufacturing an electronic device according to any one of claims 1 to 4, wherein the electronic component includes a wafer.

6. The method for manufacturing an electronic device according to claim 5, wherein the wafer includes a sapphire wafer, an indium-phosphorus wafer, a silicon-carbon wafer, a gallium-nitrogen wafer, a gallium-arsenide wafer, a silicon wafer, a germanium wafer, a germanium-arsenide wafer, a gallium-phosphorus wafer, a gallium-arsenide-aluminum wafer, or a lithium tantalate wafer.

7. A method for manufacturing an electronic device according to any one of claims 1 to 6, wherein the electronic component includes a circuit forming surface.

8. A method for manufacturing an electronic device according to any one of claims 1 to 7, wherein the step of back-grinding the electronic component includes a step of reducing the thickness of the electronic component to 100 μm or less.

9. A method for manufacturing an electronic device according to any one of claims 1 to 8, wherein the step of forming a metal layer on the back-ground surface of the electronic component is performed under reduced pressure.

10. A method for manufacturing an electronic device according to any one of claims 1 to 9, wherein at least one of the adhesive resin layer (B) and the adhesive resin layer (C) is a layer whose adhesive strength decreases due to external stimuli.

11. The method for manufacturing an electronic device according to claim 10, further comprising the step of reducing the adhesive force of at least one of the adhesive resin layers (B) and the adhesive resin layer (C) by an external stimulus.

12. The method for manufacturing an electronic device according to claim 10 or 11, wherein at least one of the adhesive resin layer (B) and the adhesive resin layer (C) comprises one or more selected from the group consisting of heat-peelable adhesive resin layers and light-peelable adhesive resin layers.

13. The method for manufacturing an electronic device according to claim 12, wherein the heat-peelable adhesive resin layer includes an adhesive resin layer whose adhesive strength decreases or is lost when heated at a temperature exceeding 100°C.

14. A method for manufacturing an electronic device according to any one of claims 1 to 13, wherein the adhesive resin (C1) constituting the adhesive resin layer (C) includes one or more selected from the group consisting of (meth)acrylic resins, urethane resins, silicone resins, polyolefin resins, polyester resins, polyamide resins, fluororesins, and styrene-diene block copolymer resins.

15. The method for manufacturing an electronic device according to any one of claims 1 to 14, wherein the thickness of the adhesive resin layer (C) is 1 μm or more and 500 μm or less.

16. A method for manufacturing an electronic device according to any one of claims 1 to 15, wherein the adhesive resin (B1) constituting the adhesive resin layer (B) includes 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.

17. The method for manufacturing an electronic device according to any one of claims 1 to 16, wherein the thickness of the adhesive resin layer (B) is 1 μm or more and 500 μm or less.

18. A method for manufacturing an electronic device according to any one of claims 1 to 17, further comprising an intermediate layer (D) between the base material layer (A) and the adhesive resin layer (B), and at least one of the two selected from between the base material layer (A) and the adhesive resin layer (C).

19. The method for manufacturing an electronic device according to claim 18, wherein the intermediate layer (D) includes a layer that hardens upon external stimulation.

20. The method for manufacturing an electronic device according to claim 18 or 19, wherein the intermediate layer (D) contains a crosslinking agent.

21. The method for manufacturing an electronic device according to claim 20, wherein the crosslinking agent comprises one or more selected from the group consisting of polyfunctional (meth)acrylate compounds and isocyanate compounds.

22. The method for manufacturing an electronic device according to any one of claims 18 to 21, wherein the intermediate layer (D) comprises one or more selected from the group consisting of thermal initiators and photoinitiators.

23. The method for manufacturing an electronic device according to claim 22, wherein the thermal initiator comprises one or more selected from the group consisting of aromatic ketones, onium salt compounds, organic peroxides, thio compounds, hexaarylbiimidazole compounds, ketoxime ester compounds, borate compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having carbon-halogen bonds, and azo compounds.

24. The method for manufacturing an electronic device according to claim 22 or 23, wherein the photoinitiator comprises an alkylphenone-based photoinitiator.

25. A method for manufacturing an electronic device according to any one of claims 18 to 24, wherein the thickness of the intermediate layer (D) is 5 μm or more and 1000 μm or less.

26. The method for manufacturing an electronic device according to any one of claims 1 to 25, wherein the base material layer (A) contains a thermoplastic resin.

27. The method for manufacturing an electronic device according to any one of claims 1 to 26, wherein the thickness of the substrate layer (A) is 1 μm or more and 500 μm or less.

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