Manufacturing method of electronic device

Abstract

To provide a method for manufacturing an electronic component which can suppress occurrences of poor sealing of an electronic component called stand-off, and wrinkles while enabling unevenness absorption equivalent to or higher than a conventional method.SOLUTION: A method for manufacturing an electronic device 200 includes: at least, a preparation step of preparing a structure 100 having an adhesive film 50 having a base material layer 10, an adhesive resin layer (A) which is provided on a first surface 10A side of the base material layer 10 and temporarily fixes the electronic component 70, an adhesive resin layer (B) provided on a second surface 10B side of the base material layer 10, and an uneven absorptive resin layer (C) which is provided between the base material layer 10 and the adhesive resin layer (A) or between the base material layer 10 and the adhesive resin layer (B) and is crosslinkable by light energy and heat energy, and an electronic component 70 which is stuck to the adhesive resin layer (A) of the adhesive film 50 and has an uneven structure; a crosslinking step of giving light energy and heat energy to the uneven absorptive resin layer (C) in the structure 100, and thereby crosslinking the uneven absorptive resin layer (C); and a sealing step of sealing an electronic component 70 by a sealing material 60.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] 2. Description of the Related Art A method for manufacturing an electronic device using an adhesive film is known as a technique that can reduce the size and weight of an electronic device (eg, a semiconductor device). An example of the application of the adhesive film in the manufacture of electronic devices is the sealing process, in which the adhesive film is (i) first fixed to a wafer or chip with an adhesive film, (ii) the fixed wafer or chip is then sealed with a sealant, and (iii) the adhesive film is then peeled off.

[0003] Patent Document 1, for example, describes a technique relating to a method for manufacturing an electronic device using an adhesive film. Patent Document 1 describes a heat-resistant adhesive sheet for use in manufacturing semiconductor device that is attached when resin-encapsulating a substrateless semiconductor chip, the heat-resistant adhesive sheet having a base layer and an adhesive layer, the adhesive layer having an adhesive strength to SUS304 of 0.5 N / 20 mm or more after lamination and hardening due to stimuli received up until the completion of the resin-encapsulating process, such that the peel strength to the package is 2.0 N / 20 mm or less.

[0004] Patent Document 2 also describes an adhesive film used for temporarily fixing electronic components when sealing the electronic components with a sealing material in the manufacturing process of an electronic device. This adhesive film includes an adhesive resin layer (A) for temporarily fixing the electronic components, an adhesive resin layer (B) used for attaching to a support substrate and having an adhesive strength reduced by an external stimulus, and an intermediate layer (C) provided between the adhesive resin layer (A) and the adhesive resin layer (B). The storage modulus E' of the intermediate layer (C) at 120°C is 1.0×10 5 Pa or more 8.0 ×10 6 Pa or less, and the loss tangent (tan δ) of the intermediate layer (C) at 120° C. is 0.1 or less.

[0005] Patent Document 3 also describes a method for manufacturing an electronic device using an adhesive film. Specifically, the method for manufacturing an electronic device described in Patent Document 3 includes at least a step (1) of preparing a structure including an adhesive film including a base layer, an adhesive resin layer provided on the first surface side of the base layer and for temporarily fixing an electronic component, and an adhesive resin layer (B) provided on the second surface side of the base layer and whose adhesive strength is reduced by an external stimulus, an electronic component attached to the adhesive resin layer (A) of the adhesive film, and a support substrate attached to the adhesive resin layer (B) of the adhesive film, at least one step (2) selected from a step (2-1) of reducing the moisture content in the adhesive film and a step (2-2) of reducing the moisture content in the structure, and a step (3) of sealing the electronic component with a sealing material.

[0006] A method for manufacturing an electronic device is also described in Patent Document 4. Specifically, the method for manufacturing an electronic device described in Patent Document 4 includes at least a preparation step of preparing a structure including a base layer, an adhesive resin layer (A) provided on a first surface side of the base layer and for temporarily fixing an electronic component, an adhesive resin layer (B) provided on a second surface side of the base layer and having an adhesive strength reduced by an external stimulus, and an unevenness-absorbing resin layer (C) provided between the base layer and the adhesive resin layer (A) or between the base layer and the adhesive resin layer (B), an electronic component attached to the adhesive resin layer (A) of the adhesive film and having an uneven structure, and a support substrate attached to the adhesive resin layer (B) of the adhesive film, and a sealing step of sealing the electronic component with a sealing material. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2011-134811 A [Patent Document 2] JP 2018-157037 A [Patent Document 3] International Publication No. 2019 / 188543 [Patent Document 4] International Publication No. 2020 / 184201 Summary of the Invention [Problem to be solved by the invention]

[0008] According to the inventors' research, it has become clear that when an electronic component having an uneven structure, such as a bump, is placed on an adhesive film and then sealed with a sealing material, the electronic component may become misaligned in the horizontal direction (hereinafter also referred to as misalignment of the electronic component) or the sealing material may get in between the adhesive film and the electronic component.

[0009] In order to improve the above-mentioned points, it is considered effective to use, for example, an adhesive film having an irregularity-absorbing resin layer as described in Patent Document 4. By using an adhesive film having an irregularity-absorbing resin layer, it is possible to suppress the displacement of electronic components during the sealing process and the intrusion of sealing material between the adhesive film and the electronic components.

[0010] However, as shown in Figures 4(a) to (c), when an adhesive film 50A having an unevenness-absorbing resin layer is used, when an electronic component 70A having an uneven structure 75A is arranged and sealed with a sealant 60A, the unevenness-absorbing resin layer is softened by heat, and the electronic component 70A is likely to sink into the adhesive film 50A due to the pressure of the sealant 60A. As a result, it has become clear that there are cases where a seal failure of the electronic component 70A, called a standoff 90 (part of the side surface of the electronic component 70A is not sealed) or wrinkles occur on the surface of the sealant after sealing, as shown in Figure 4(d).

[0011] The present inventors have conducted research to solve the above-mentioned problems of stand-off and wrinkles, and have found that an adhesive film having a crosslinkable unevenness-absorbing resin layer is effective. The present inventors have conducted further research and found that there is still room for improvement in both photocrosslinkable resins and thermally crosslinkable resins. That is, when the support is opaque to light, light is applied from the side where the chip is fixed, but the light does not reach the area directly below the chip, which tends to result in insufficient curing of the photocrosslinkable intermediate layer. When a thermally crosslinkable intermediate layer is used, the surface of the adhesive layer between the chips is exposed to air, so the radicals generated from the added curing agent are quenched by oxygen, which can lead to insufficient curing of the intermediate layer. The present invention has been made in view of the above circumstances. One of the objects of the present invention is to provide a method for manufacturing electronic components that can absorb unevenness at least as well as conventional methods while suppressing the occurrence of standoffs, which are sealing defects of electronic components, and wrinkles. [Means for solving the problem]

[0012] The present inventors have conducted extensive research to achieve the above object, and as a result, have found that the use of an adhesive film having an unevenness-absorbing resin layer that can be crosslinked by light energy and thermal energy as an adhesive film can suppress the occurrence of standoffs, which are sealing defects of electronic components, and wrinkles, thereby completing the present invention.

[0013] According to the present invention, there is provided a method for manufacturing an electronic component as described below.

[0014] [1] an adhesive film comprising a base layer, an adhesive resin layer (A) provided on a first surface side of the base layer for temporarily fixing an electronic component, an adhesive resin layer (B) provided on a second surface side of the base layer, and an unevenness-absorbing resin layer (C) provided between the base layer and the adhesive resin layer (A) or between the base layer and the adhesive resin layer (B) and crosslinkable by light energy and thermal energy; an electronic component attached to the adhesive resin layer (A) of the adhesive film and having a concave-convex structure; A preparation step of preparing a structure comprising: a crosslinking step of crosslinking the unevenness-absorbing resin layer (C) in the structure by applying light energy and heat energy to the unevenness-absorbing resin layer (C); a sealing step of sealing the electronic component with a sealing material; A method for manufacturing an electronic device comprising at least the steps of: [2] The crosslinking step comprises: a first crosslinking step of crosslinking the unevenness-absorbing resin layer (C) by irradiating the structure with light; a second crosslinking step of further crosslinking the unevenness-absorbing resin layer (C) by heating the structure; A method for manufacturing an electronic device according to the above [1], comprising at least the steps of: [3] In the method for producing an electronic device according to the above [1] or [2], The method for producing an electronic device, wherein the unevenness-absorbing resin layer (C) comprises a resin, a crosslinking agent, a photoinitiator, and a thermal initiator. [4] The method for producing an electronic device according to [3] above, wherein the photoinitiator comprises an alkylphenone-based photoinitiator. [5] The method for producing an electronic device according to the above-mentioned [3] or [4], wherein the thermal initiator comprises one or more selected from 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 a carbon-halogen bond, and azo compounds. [6] In the method for producing an electronic device according to any one of the above [1] to [5], The method for manufacturing an electronic device, wherein the uneven structure of the electronic component includes bump electrodes. [7] In the method for producing an electronic device according to any one of the above [1] to [6], The storage modulus E' at 125°C of the unevenness-absorbing resin layer (C') obtained by crosslinking the unevenness-absorbing resin layer (C) is 1.0 × 10 6 Pa or more 1.0×10 9 A method for manufacturing an electronic device, the manufacturing method thereof being less than 100 Pa. [8] In the method for producing an electronic device according to any one of the above [1] to [7], A method for producing an electronic device, wherein the unevenness-absorbing resin layer (C) has a thickness of 5 μm or more and 1000 μm or less. [9] In the method for producing an electronic device according to any one of the above items [1] to [8], The method for producing an electronic device further comprises a support substrate on which the structure is attached to the adhesive resin layer (B).

[10] In the method for producing an electronic device according to the above [9], The method for producing an electronic device further comprises, after the sealing step, a first peeling step of peeling off the support substrate from the structure by applying an external stimulus to reduce the adhesive strength of the adhesive resin layer (B).

[11] In the method for producing an electronic device according to the above

[10] , The method for producing an electronic device further comprises, after the first peeling step, a second peeling step of peeling the adhesive film from the electronic component.

[12] In the method for producing an electronic device according to any one of the above items [1] to

[11] , The method for producing an electronic device, wherein the sealing material is an epoxy resin-based sealing material.

[13] In the method for producing an electronic device according to any one of the above items [1] to

[12] , The adhesive resin layer (A) contains an adhesive resin, The method for manufacturing an electronic device, wherein the adhesive resin contains one or more types selected from the group consisting of (meth)acrylic adhesive resins, silicone adhesive resins, urethane adhesive resins, olefin adhesive resins and styrene adhesive resins.

[14] A base layer; an adhesive film including: an adhesive resin layer (A) provided on the first surface side of the base material layer and for temporarily fixing an electronic component; and an unevenness-absorbing resin layer (C) provided between the base material layer and the adhesive resin layer (A) and capable of being crosslinked by light energy and thermal energy; a preparation step of preparing a structure including an electronic component attached to the adhesive resin layer (A) of the adhesive film and having a concave-convex structure; a first crosslinking step of crosslinking the unevenness-absorbing resin layer (C) in the structure by irradiating the unevenness-absorbing resin layer (C) with light; a second crosslinking step of further crosslinking the unevenness-absorbing resin layer (C) in the structure by heating the unevenness-absorbing resin layer (C); a sealing step of sealing the electronic component with a sealing material; A method for manufacturing an electronic device comprising at least the steps of: Effect of the Invention

[0015] According to the present invention, it is possible to provide a method for manufacturing electronic components that can absorb unevenness to an equal or greater extent than in the past, while suppressing the occurrence of standoffs, which are defective sealing of electronic components, and wrinkles. [Brief description of the drawings]

[0016] [Figure 1] 1 is a cross-sectional view showing a schematic example of a structure of an adhesive film according to an embodiment of the present invention. [Diagram 2] 1A to 1C are cross-sectional views illustrating an example of a method for manufacturing an electronic device according to an embodiment of the present invention. [Diagram 3] 1A to 1C are cross-sectional views illustrating an example of a method for manufacturing an electronic device according to an embodiment of the present invention. [Figure 4] FIG. 1 is a diagram for explaining a sealing defect of an electronic component called a standoff. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and the description thereof will be omitted as appropriate. In addition, the drawings are schematic views, and the actual dimensional ratios are not necessarily the same. In the present specification, unless otherwise specified, the expression "A to B" regarding a numerical range means greater than or equal to A and less than or equal to B. For example, 1 to 5% means greater than or equal to 1% and less than or equal to 5%. In the present specification, "(meth)acrylic" means acrylic, methacrylic, or both acrylic and methacrylic.

[0018] 1. Manufacturing method of electronic device A method for manufacturing an electronic device according to this embodiment will be described below. Figures 2 and 3 are cross-sectional views that typically show an example of a method for manufacturing an electronic device according to an embodiment of the present invention. The method for manufacturing an electronic device according to this embodiment includes at least the following three steps. (1) an adhesive film 50 including a base layer 10, an adhesive resin layer (A) provided on a first surface 10A of the base layer 10 and for temporarily fixing an electronic component 70, an adhesive resin layer (B) provided on a second surface 10B of the base layer 10, and an unevenness-absorbing resin layer (C) provided between the base layer 10 and the adhesive resin layer (A) or between the base layer 10 and the adhesive resin layer (B) and crosslinkable by light energy and thermal energy; A preparation step of preparing a structure 100 including an electronic component 70 attached to the adhesive resin layer (A) of the adhesive film 50 and having a concave-convex structure 75. (2) A crosslinking step of crosslinking the unevenness-absorbing resin layer (C) in the structure 100 by applying light energy and heat energy to the unevenness-absorbing resin layer (C). (3) Sealing process of sealing electronic components 70 with sealing material 60

[0019] Each step of the method for manufacturing an electronic device according to this embodiment will be described below.

[0020] ((1) Preparation process) In the preparation step, a structure 100 is prepared, which includes an adhesive film 50 and an electronic component 70 attached to the adhesive resin layer (A) of the adhesive film 50 and having a concave-convex structure 75. Here, it is preferable that the structure 100 further includes a support substrate 80 attached to the adhesive resin layer (B) of the adhesive film 50.

[0021] Such a structure 100 can be fabricated, for example, by the following procedure. First, the adhesive film 50 is attached onto the support substrate 80 so that the adhesive resin layer (B) faces the support substrate 80. A protective film called a separator may be attached onto the adhesive resin layer (B), and the protective film can be peeled off to attach the exposed surface of the adhesive resin layer (B) to the surface of the support substrate 80. The support substrate 80 may be, for example, a quartz substrate, a glass substrate, or a SUS substrate.

[0022] Next, electronic component 70 is placed on adhesive resin layer (A) of adhesive film 50, whereby structure 100 can be obtained. Examples of the electronic component 70 include semiconductor chips such as ICs, LSIs, discrete devices, light-emitting diodes, and light-receiving elements, semiconductor panels, and semiconductor packages. The surface of the electronic component 70 has an uneven structure 75 due to, for example, the presence of electrodes. Furthermore, for example, when mounting an electronic device on a mounting surface, the electrodes are joined to electrodes formed on the mounting surface to form an electrical connection between the electronic device and the mounting surface (the mounting surface of a printed circuit board or the like). Examples of the electrodes include bump electrodes such as ball bumps, printed bumps, stud bumps, plated bumps, and pillar bumps. That is, the electrodes are usually convex electrodes. These bump electrodes may be used alone or in combination of two or more types. The metal species constituting the bump electrode is not particularly limited, and examples thereof include silver, gold, copper, tin, lead, bismuth, and alloys thereof. These metal species may be used alone or in combination of two or more.

[0023] ((2) Crosslinking process) Next, the unevenness-absorbing resin layer (C) in the structure 100 is crosslinked by applying light energy and heat energy to the unevenness-absorbing resin layer (C). That is, the unevenness-absorbing resin layer (C) in the structure 100 is crosslinked by applying light energy to the unevenness-absorbing resin layer (C) by irradiating it with light and applying heat energy by heating. At this time, the light irradiation and heating may be performed sequentially or simultaneously, but it is preferable to perform a first crosslinking step of crosslinking the unevenness-absorbing resin layer (C) by irradiating the unevenness-absorbing resin layer (C) with light, and a second crosslinking step of further crosslinking the unevenness-absorbing resin layer (C) by heating the unevenness-absorbing resin layer (C) in this order. That is, in the manufacturing method of the electronic device of this embodiment, it is preferable that the (2) crosslinking step at least includes a first crosslinking step of crosslinking the unevenness-absorbing resin layer (C) by irradiating the structure with light, and a second crosslinking step of further crosslinking the unevenness-absorbing resin layer (C) by heating the structure.

[0024] The unevenness-absorbing resin layer (C) is crosslinked and cured by irradiating it with light such as ultraviolet light. The light source used here is not particularly limited, but it is preferable to use a light source capable of irradiating ultraviolet light containing a wavelength component capable of exciting the photoinitiator, and it is more preferable to use a light source capable of irradiating ultraviolet light containing a component with a wavelength of less than 300 nm. Examples of such light sources include high-pressure mercury lamps, low-pressure mercury lamps, metal halide lamps, and super UV lamps. The light irradiated by the light source may contain a component with a wavelength of 300 nm or more. In the case of ultraviolet crosslinking, for example, in an environment of 0 to 60°C, ultraviolet rays with a main wavelength of 365 nm are irradiated using a high-pressure mercury lamp at an irradiation intensity of 10 to 350 mW / cm 2 UV dose 100-20000mJ / cm 2 By irradiating the unevenness-absorbing resin layer (C) under the above conditions, the unevenness-absorbing resin layer (C) can be crosslinked and cured.

[0025] The method of crosslinking the unevenness-absorbing resin layer (C) by heating is not limited, but preferred examples include thermal crosslinking in an oven, thermal crosslinking on a hot plate, and thermal crosslinking by infrared radiation. In the case of thermal crosslinking, the heating temperature is, for example, 100°C to 180°C, and the heat treatment time is, for example, 10 to 180 minutes. It is preferable that the heating temperature does not exceed the temperature at which gas is generated or the temperature at which the heat-expandable microspheres thermally expand.

[0026] ((3) Sealing process) Next, the electronic components 70 are encapsulated with the encapsulant 60 . The electronic component 70 is covered with the sealing material 60, and the sealing material 60 is cured at a temperature of, for example, 150° C. or less or 170° C. or less to seal the electronic component 70. When the adhesive resin layer (B) of the adhesive film 50 contains at least one selected from a gas-generating component and heat-expandable microspheres, the temperature for curing the sealing material 60 is preferably within a range not exceeding the temperature at which gas is generated or the temperature at which the heat-expandable microspheres thermally expand. The form of the sealing material 60 is not particularly limited, but may be, for example, granular, sheet-like, or liquid.

[0027] As the sealing material 60, it is preferable to use one or two types selected from an epoxy resin-based sealing material using an epoxy resin and a silicone resin-based sealing material using a silicone resin. In particular, a liquid epoxy resin-based or silicone resin-based sealing material is preferred, as this improves the affinity of the sealing material 60 to the adhesive film 50 and enables the electronic components 70 to be sealed more evenly. As such an epoxy resin-based sealing material, for example, T693 / R4000 series, T693 / R1000 series, T693 / R5000 series, etc. manufactured by Nagase ChemteX Corporation can be used. Examples of such silicone resin-based sealing materials that can be used include KMC-8400 manufactured by Shin-Etsu Chemical Co., Ltd., and TSE3033 and TSE3251 manufactured by Momentive Performance Materials Japan, Inc.

[0028] Examples of the sealing method include transfer molding, injection molding, compression molding, cast molding, etc. After sealing the electronic component 70 with the sealing material 60, the sealing material 60 is cured by heating at a temperature of, for example, 150° C. or less or 170° C. or less, to obtain the structure 100 in which the electronic component 70 is sealed.

[0029] ((4) First peeling process) In the manufacturing method for an electronic device according to this embodiment, as shown in FIG. 3(4), after the (3) sealing step, a first peeling step may be further provided in which an external stimulus is applied to reduce the adhesive strength of the adhesive resin layer (B) to peel off the support substrate 80 from the structure 100. The support substrate 80 can be easily removed from the adhesive film 50, for example, by sealing the electronic components 70 and then heating the support substrate 80 to a temperature exceeding 150°C or a temperature exceeding 170°C to reduce the adhesive strength of the adhesive resin layer (B).

[0030] ((5) Second peeling process) In the method for manufacturing an electronic device according to this embodiment, as shown in FIG. 3(5), after the first peeling step, a second peeling step may be further provided in which the adhesive film 50 is peeled off from the electronic component 70 to obtain the electronic device 200. Methods for peeling the adhesive film 50 from the electronic component 70 include, for example, a mechanical peeling method, a method in which the adhesive strength of the surface of the adhesive film 50 is reduced before peeling, and the like.

[0031] (Other processes) The method for manufacturing an electronic device according to this embodiment may further include a step (6) of forming a wiring layer 310 and a bump 320 on the exposed surface of the obtained electronic device 200 to obtain the electronic device 300, as shown in FIG. 3(6).

[0032] The wiring layer 310 includes pads (not shown) that are external connection terminals formed on the outermost surface, and wiring (not shown) that electrically connects the pads to the exposed electronic components 70. The wiring layer 310 can be formed by a conventionally known method, and may have a multi-layer structure.

[0033] Then, bumps 320 are formed on the pads of the wiring layer 310, and the electronic device 300 can be obtained. Examples of the bumps 320 include solder bumps and gold bumps. The solder bumps can be formed, for example, by placing solder balls on the pads that are external connection terminals of the wiring layer 310 and heating the solder to melt (reflow). The gold bumps can be formed by ball bonding, plating, Au ball transfer, or other methods.

[0034] Moreover, the method for manufacturing an electronic device according to this embodiment may further include a step (7) of dicing the electronic device 300 to obtain a plurality of electronic devices 400, as shown in FIG. The electronic device 300 can be diced by a known method.

[0035] As another embodiment, the method for producing an electronic device according to the present embodiment may be configured not to use the adhesive resin layer (B). That is, as another embodiment, the method for producing an electronic device according to the present embodiment includes at least the following four steps. (1) an adhesive film 50 including a base layer 10, an adhesive resin layer (A) provided on a first surface 10A side of the base layer 10 and for temporarily fixing an electronic component 70, and an unevenness-absorbing resin layer (C) provided between the base layer 10 and the adhesive resin layer (A) and capable of being crosslinked by light energy and thermal energy; A preparation step of preparing a structure 100 including an electronic component 70 attached to the adhesive resin layer (A) of the adhesive film 50 and having a concave-convex structure 75. (2) A first crosslinking step of crosslinking the unevenness-absorbing resin layer (C) in the structure 100 by irradiating the unevenness-absorbing resin layer (C) with light. (3) A second crosslinking step in which the unevenness-absorbing resin layer (C) in the structure 100 is heated to further crosslink the unevenness-absorbing resin layer (C). (4) Sealing process of sealing electronic components 70 with sealing material 60

[0036] 2. Adhesive film Next, the adhesive film 50 according to this embodiment will be described. FIG. 1 is a cross-sectional view that illustrates an example of the structure of an adhesive film 50 according to an embodiment of the present invention.

[0037] As shown in FIG. 1, the adhesive film 50 of this embodiment comprises a base layer 10, an adhesive resin layer (A) provided on the first surface 10A side of the base layer 10 for temporarily fixing an electronic component, an adhesive resin layer (B) provided on the second surface 10B side of the base layer 10, and an unevenness-absorbing resin layer (C) provided between the base layer 10 and the adhesive resin layer (A) or between the base layer 10 and the adhesive resin layer (B) and capable of being crosslinked by light energy and thermal energy. From the viewpoint of further improving the unevenness-absorbing properties of the adhesive film 50, the unevenness-absorbing resin layer (C) is preferably located at least between the base layer 10 and the adhesive resin layer (A). When the unevenness-absorbing resin layer (C) is located between the base layer 10 and the adhesive resin layer (A), another unevenness-absorbing resin layer (C2) may be further located between the adhesive resin layer (B) and the base layer 10. In this case, the unevenness-absorbing resin layer (C) and the unevenness-absorbing resin layer (C2) may be the same or different in terms of material, thickness, etc.

[0038] As described above, according to the inventors' investigations, by using an adhesive film having an unevenness-absorbing resin layer as described in Patent Document 4 as the adhesive film, it is possible to prevent the electronic components from shifting in position during the sealing process and the sealing material from entering between the adhesive film and the electronic components. However, as shown in Figures 4(a) to (c), when an adhesive film 50A having an unevenness-absorbing resin layer is used, when an electronic component 70A having an uneven structure 75A is arranged and sealed with a sealant 60A, the unevenness-absorbing resin layer is softened by heat, and the electronic component 70A is likely to sink into the adhesive film 50A due to the pressure of the sealant 60A. As a result, a sealing failure of the electronic component 70A, called a standoff 90, may occur as shown in Figure 4(d).

[0039] The present inventors have conducted extensive research to realize an adhesive film capable of suppressing displacement of electronic components during the sealing process, and the intrusion of a sealant between the adhesive film and the electronic components, as well as suppressing the occurrence of stand-off during the sealing process. As a result, it has been found for the first time that an adhesive film 50 comprising a base layer 10, an adhesive resin layer (A) provided on the first surface 10A side of the base layer 10 and for temporarily fixing electronic components, an adhesive resin layer (B) provided on the second surface 10B side of the base layer 10, and an unevenness-absorbing resin layer (C) provided between the base layer 10 and the adhesive resin layer (A) or between the base layer 10 and the adhesive resin layer (B) and capable of crosslinking by light energy and thermal energy, can suppress displacement of electronic components during the sealing process, and the intrusion of a sealant between the adhesive film and the electronic components, as well as suppress the occurrence of stand-off during the sealing process.

[0040] That is, according to the present embodiment, by using the adhesive film 50 having the unevenness-absorbing resin layer (C) that can be crosslinked by light energy and thermal energy as an adhesive film for temporarily fixing an electronic component having an uneven structure, the adhesive film 50 has improved adhesion to the electronic component having an uneven structure. Therefore, in the process of sealing the electronic component, it is possible to suppress the position of the electronic component being shifted due to pressure caused by the flow of the sealing material, and the sealing material being intruded between the adhesive film and the electronic component. Furthermore, after the electronic component having an uneven structure is temporarily fixed, the unevenness-absorbing resin layer (C) is crosslinked and cured by light energy and thermal energy to increase the elastic modulus, thereby suppressing the electronic component from sinking into the adhesive film in the process of sealing the electronic component. That is, by designing the unevenness-absorbing resin layer (C) so that it crosslinks and changes its elastic modulus when exposed to light energy and thermal energy, (i) before light energy and thermal energy are applied, the unevenness-absorbing resin layer (C) can sufficiently deform to conform to the uneven structure of the electronic component, and (ii) on the other hand, after light energy and thermal energy are applied, movement of the electronic component is suppressed.

[0041] Furthermore, it was found for the first time that the occurrence of wrinkles on the surface of the sealing material after sealing can be suppressed by crosslinking and curing the unevenness-absorbing resin layer (C) using light energy and heat energy. Although the mechanism is unclear, it is considered that when irradiation is performed from the side of the electronic components 70 in Fig. 2, the area directly below the electronic components that is not hit by the light will not be sufficiently photocured. In addition, since the adhesive layer surface between the electronic components 70 is exposed to air, it is considered that active chemical species such as radicals and cations generated from the initiator are quenched by oxygen, that is, so-called oxygen inhibition makes it difficult for thermal curing to occur. In this case, it is considered that by performing crosslinking curing of the unevenness-absorbing resin layer (C) using both light energy and thermal energy, it is possible to perform crosslinking curing of the unevenness-absorbing resin layer (C) so as to compensate for the areas that are difficult to cure using each type of energy. As a result, it is presumed that it is possible to suppress the occurrence of wrinkles on the surface of the sealing material after sealing, which is caused by insufficient crosslinking and curing of the unevenness-absorbing resin layer (C).

[0042] As described above, the adhesive film 50 of this embodiment can prevent misalignment of electronic components during the sealing process and infiltration of sealing material between the adhesive film and the electronic components, and can also prevent standoffs and wrinkles during the sealing process.

[0043] The total thickness of the adhesive film 50 according to this embodiment is preferably 10 μm or more and 1000 μm or less, and more preferably 20 μm or more and 500 μm or less, from the viewpoint of the balance between mechanical properties and ease of handling.

[0044] The adhesive film 50 according to this embodiment can be used, for example, as a film for temporarily fixing electronic components when sealing the electronic components with a sealing material in the manufacturing process of an electronic device.

[0045] Next, each layer constituting the adhesive film 50 according to this embodiment will be described.

[0046] <Base material layer> The base layer 10 is a layer provided for the purpose of improving the properties of the adhesive film 50, such as handleability, mechanical properties, and heat resistance. The base layer 10 is not particularly limited, but may be, for example, a resin film. Examples of resins constituting the resin film include known thermoplastic resins, such as 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; polyacrylates; polymethacrylates; polyvinyl chloride; polyvinylidene chloride; polyimides; polyetherimides; ethylene-vinyl acetate copolymers; polyacrylonitrile; polycarbonates; polystyrenes; ionomers; polysulfones; polyethersulfones; and polyphenylene ethers. Among these, from the viewpoint of an excellent balance of transparency, mechanical strength, price, and the like, one or more selected from polypropylene, polyethylene terephthalate, polyethylene naphthalate, polyamide, and polyimide are preferred, and at least one selected from polyethylene terephthalate and polyethylene naphthalate is more preferred.

[0047] The substrate layer 10 may be a single layer or two or more layers. The resin film used to form the base layer 10 may be in the form of a stretched film or a uniaxially or biaxially stretched film. From the viewpoint of improving the mechanical strength of the base layer 10, however, a uniaxially or biaxially stretched film is preferable.

[0048] From the viewpoint of obtaining good film properties, the thickness of the base layer 10 is preferably 1 μm or more and 500 μm or less, more preferably 5 μm or more and 300 μm or less, and further preferably 10 μm or more and 250 μm or less. The substrate layer 10 may be subjected to a surface treatment in order to improve adhesion to other layers. Specifically, corona treatment, plasma treatment, undercoat treatment, primer coat treatment, etc. may be performed.

[0049] <Adhesive resin layer (A)> The adhesive resin layer (A) is a layer provided on one surface side of the base layer 10. The adhesive resin layer (A) is a layer for temporarily fixing an electronic component by contacting the surface of the electronic component when the electronic component is sealed with a sealing material in a manufacturing process of an electronic device, for example.

[0050] The adhesive resin layer (A) preferably contains an adhesive resin (A1). The adhesive resin (A1) preferably contains one or more selected from the group consisting of (meth)acrylic adhesive resins (a), silicone adhesive resins, urethane adhesive resins, olefin adhesive resins, and styrene adhesive resins. Among these, the (meth)acrylic adhesive resin (a) is preferred from the viewpoint of easily adjusting the adhesive strength.

[0051] The adhesive resin layer (A) may be a radiation-crosslinked adhesive resin layer whose adhesive strength can be reduced by radiation. When the radiation-crosslinked adhesive resin layer is irradiated with radiation, crosslinking occurs and the adhesive strength is significantly reduced, making it easier to peel the adhesive film 50 from the electronic component. Examples of radiation include ultraviolet rays, electron beams, and infrared rays. The radiation crosslinkable adhesive resin layer is preferably an ultraviolet crosslinkable adhesive resin layer.

[0052] The (meth)acrylic adhesive resin (a) used in the adhesive resin layer (A) may be, for example, a copolymer containing a (meth)acrylic acid alkyl ester monomer unit (a1) and a monomer unit (a2) having a functional group capable of reacting with a crosslinking agent. In this embodiment, the (meth)acrylic acid alkyl ester means an acrylic acid alkyl ester, a methacrylic acid alkyl ester, or a mixture thereof.

[0053] The (meth)acrylic adhesive resin (a) according to this embodiment can be obtained, for example, by copolymerizing a monomer mixture containing a (meth)acrylic acid alkyl ester monomer (a1) and a monomer (a2) having a functional group capable of reacting with a crosslinking agent.

[0054] Examples of the monomer (a1) forming the (meth)acrylic acid alkyl ester monomer unit (a1) include (meth)acrylic acid alkyl esters having an alkyl group with about 1 to 12 carbon atoms. Preferred are (meth)acrylic acid alkyl esters having an alkyl group with 1 to 8 carbon atoms. Specific examples include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, and 2-ethylhexyl methacrylate. These may be used alone or in combination of two or more. In the (meth)acrylic adhesive resin (a) according to this embodiment, the content of the (meth)acrylic acid alkyl ester monomer unit (a1) is preferably from 10 mass% to 98.9 mass%, more preferably from 50 mass% to 97 mass%, and even more preferably from 85 mass% to 95 mass%, when the sum of all monomer units in the (meth)acrylic adhesive resin (a) is 100 mass%.

[0055] Examples of the monomer (a2) that forms the monomer unit (a2) having a functional group that can react with a crosslinking agent include acrylic acid, methacrylic acid, itaconic acid, mesaconic acid, citraconic acid, fumaric acid, maleic acid, itaconic acid monoalkyl ester, mesaconic acid monoalkyl ester, citraconic acid monoalkyl ester, fumaric acid monoalkyl ester, maleic acid monoalkyl ester, acrylate, methacrylate, 2-hydroxyethyl acrylate, methacrylate, acrylamide, methacrylamide, tertiary butylaminoethyl acrylate, tertiary butylaminoethyl methacrylate, etc. Preferred are acrylic acid, methacrylic acid, acrylate, 2-hydroxyethyl acrylate, methacrylate, acrylamide, methacrylamide, etc. These may be used alone or in combination of two or more. In the (meth)acrylic adhesive resin (a) according to this embodiment, the content of the monomer unit (a2) is preferably from 1 to 40% by mass, more preferably from 1 to 20% by mass, and even more preferably from 1 to 10% by mass, when the sum of all monomer units in the (meth)acrylic adhesive resin (a) is taken as 100% by mass.

[0056] The (meth)acrylic adhesive resin (a) according to this embodiment may further contain, in addition to the monomer unit (a1) and the monomer unit (a2), a bifunctional monomer unit (a3) ​​or a specific comonomer unit having surfactant properties (hereinafter referred to as a polymerizable surfactant). The polymerizable surfactant has the property of copolymerizing with the monomers (a1), (a2) and (a3), and also acts as an emulsifier in the case of emulsion polymerization.

[0057] Examples of the monomer (a3) ​​forming the bifunctional monomer unit (a3) ​​include allyl methacrylate, allyl acrylate, divinylbenzene, vinyl methacrylate, vinyl acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tetraethylene glycol di(meth)acrylate, and, for example, those having diacrylate or dimethacrylate at both ends and a main chain structure of propylene glycol type (e.g., Nippon Oil & Fats Corporation, trade names: PDP-200, PDP-400, ADP-200, ADP-400), tetramethylene glycol type (e.g., Nippon Oil & Fats Corporation, trade names: ADT-250, ADT-850) and mixtures thereof (e.g., Nippon Oil & Fats Corporation, trade names: ADET-1800, ADPT-4000).

[0058] In the (meth)acrylic adhesive resin (a) according to this embodiment, the content of the monomer unit (a3) ​​is preferably from 0.1 to 30% by mass, more preferably from 0.1 to 20% by mass, even more preferably from 0.1 to 15% by mass, and particularly preferably from 0.1 to 5% by mass, when the sum of all monomer units in the (meth)acrylic adhesive resin (a) is 100% by mass.

[0059] Examples of polymerizable surfactants include those in which a polymerizable 1-propenyl group has been introduced into the benzene ring of polyoxyethylene nonylphenyl ether (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.; trade names: Aqualon RN-10, RN-20, RN-30, RN-50, etc.), those in which a polymerizable 1-propenyl group has been introduced into the benzene ring of an ammonium salt of a sulfate ester of polyoxyethylene nonylphenyl ether (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.; trade names: Aqualon HS-10, HS-20, HS-1025, etc.), and sulfosuccinic acid diesters having a polymerizable double bond in the molecule (manufactured by Kao Corporation; trade names: Latemul S-120A, S-180A, etc.). In the (meth)acrylic adhesive resin (a) according to this embodiment, the content of the polymerizable surfactant is preferably from 0.1 to 30% by mass, more preferably from 0.1 to 20% by mass, even more preferably from 0.1 to 15% by mass, and particularly preferably from 0.1 to 5% by mass, when the sum of all monomer units in the (meth)acrylic adhesive resin (a) is taken as 100% by mass.

[0060] The (meth)acrylic adhesive resin (a) according to this embodiment may further contain, if necessary, a monomer unit formed from a monomer having a polymerizable double bond, such as vinyl acetate, acrylonitrile, or styrene.

[0061] The polymerization reaction mechanism of the (meth)acrylic adhesive resin (a) according to the present embodiment may be radical polymerization, anionic polymerization, cationic polymerization, etc. Considering the production cost of the (meth)acrylic adhesive resin (a), the effect of the functional group of the monomer, the effect of ions on the surface of the electronic component, etc., it is preferable to polymerize by radical polymerization. When polymerizing by radical polymerization reaction, the following radical polymerization initiators are used: 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 Examples of the peroxides include organic peroxides such as 2-ethylhexanoate, t-butylperoxy-3,5,5-trimethylhexanoate, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, t-butyl peroxide, and di-t-amyl peroxide; inorganic peroxides such as ammonium persulfate, potassium persulfate, and sodium persulfate; and azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, and 4,4'-azobis-4-cyanovaleric acid.

[0062] When polymerization is performed by emulsion polymerization, among these radical polymerization initiators, inorganic peroxides such as water-soluble ammonium persulfate, potassium persulfate, and sodium persulfate, and azo compounds having a carboxyl group in the molecule such as water-soluble 4,4'-azobis-4-cyanovaleric acid are preferred. Considering the influence of ions on the surface of electronic components, azo compounds having a carboxyl group in the molecule such as ammonium persulfate and 4,4'-azobis-4-cyanovaleric acid are more preferred, and azo compounds having a carboxyl group in the molecule such as 4,4'-azobis-4-cyanovaleric acid are particularly preferred.

[0063] The adhesive resin layer (A) according to this embodiment preferably further contains, in addition to the adhesive resin (A1), a crosslinking agent (A2) having two or more crosslinkable functional groups in one molecule. The crosslinking agent (A2) having two or more crosslinkable functional groups in one molecule can be used to adjust the adhesive strength and cohesive strength by reacting with the functional groups of the adhesive resin (A1). Examples of such crosslinking agents (A2) include epoxy compounds such as sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, neopentyl glycol diglycidyl ether, and resorcin diglycidyl ether; isocyanate compounds such as tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate triadduct of trimethylolpropane, polyisocyanate, diphenylmethane diisocyanate, and tolylene diisocyanate; and trimethylolpropane-tri-β-aziridinylpropionate. aziridine-based compounds such as N,N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide), N,N'-hexamethylene-1,6-bis(1-aziridinecarboxamide), N,N'-toluene-2,4-bis(1-aziridinecarboxamide), and trimethylolpropane-tri-β-(2-methylaziridine)propionate; tetrafunctional epoxy-based compounds such as N,N,N',N'-tetraglycidyl-m-xylylenediamine and 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane; and melamine-based compounds such as hexamethoxymethylolmelamine. These may be used alone or in combination of two or more. Among these, it is preferable to contain one or more compounds selected from the group consisting of epoxy compounds, isocyanate compounds, and aziridine compounds.

[0064] The content of the crosslinking agent (A2) is usually preferably within a range in which the number of functional groups in the crosslinking agent (A2) is not greater than the number of functional groups in the adhesive resin (A1). However, if necessary, an excess of the crosslinking agent (A2) may be contained when new functional groups are generated by the crosslinking reaction or when the crosslinking reaction is slow. The content of the crosslinking agent (A2) in the adhesive resin layer (A) is preferably 0.1 parts by mass or more and 15 parts by mass or less per 100 parts by mass of the adhesive resin (A1), from the viewpoint of improving the balance between the heat resistance and adhesion of the adhesive resin layer (A).

[0065] The adhesive resin layer (A) may contain additives such as plasticizers and tackifier resins as other components. When the adhesive resin layer (A) is a radiation crosslinking adhesive resin layer, it may contain various additives for radiation crosslinking. The total content of the adhesive resin (A1) and the crosslinking agent (A2) in the adhesive resin layer (A) is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more, when the entire adhesive resin layer (A) is taken as 100% by mass. This can further suppress adhesive residue on the electronic component side when the adhesive film is peeled off from the electronic component.

[0066] The adhesive resin layer (A) may be a single layer or multiple layers. The thickness of the adhesive resin layer (A) is not particularly limited, but is, for example, preferably from 1 μm to 100 μm, and more preferably from 3 μm to 50 μm.

[0067] The adhesive resin layer (A) can be formed, for example, by applying an adhesive onto the base layer 10 or the irregularity-absorbing resin layer (C). The adhesive may be dissolved in a solvent and applied as a coating liquid, or may be applied as a water-based emulsion, or the liquid adhesive may be directly applied. Among them, the aqueous emulsion coating liquid is preferable. Examples of the aqueous emulsion coating liquid include a coating liquid in which a (meth)acrylic adhesive resin (a), a silicone adhesive resin, a urethane adhesive resin, an olefin adhesive resin, a styrene adhesive resin, or the like is dispersed in water. A pressure-sensitive adhesive coating solution dissolved in an organic solvent may be used. The organic solvent is not particularly limited, and may be appropriately selected from known solvents in consideration of solubility and drying time. Examples of organic solvents include esters such as ethyl acetate and methyl acetate; ketones such as acetone and MEK; aromatics such as benzene, toluene, and ethylbenzene; linear or cyclic aliphatics such as heptane, hexane, and cyclohexane; and alcohols such as isopropanol and butanol. Ethyl acetate and toluene are preferred as organic solvents. These solvents may be used alone or in combination of two or more.

[0068] The adhesive coating liquid can be coated by a conventional coating method such as a roll coater method, a reverse roll coater method, a gravure roll method, a bar coat method, a comma coater method, a die coater method, etc. There is no particular restriction on the drying conditions of the coated adhesive, but it is generally preferable to dry the coated adhesive at a temperature range of 80 to 200°C for 10 seconds to 10 minutes. It is more preferable to dry the coated adhesive at 80 to 170°C for 15 seconds to 5 minutes. In order to sufficiently promote the crosslinking reaction between the crosslinking agent and the adhesive, the adhesive coating liquid may be heated at 40 to 80°C for about 5 to 300 hours after drying is completed.

[0069] The base layer 10 and the adhesive resin layer (A) or the irregularity-absorbing resin layer (C) may be formed by co-extrusion, or the film-like base layer 10 and the film-like adhesive resin layer (A) may be laminated together. In the examples described later, the adhesive film is manufactured by first forming the adhesive resin layer (A) on the surface of a separator (release film), and then bonding the adhesive resin layer (A) to another layer.

[0070] <Adhesive resin layer (B)> The adhesive film 50 according to this embodiment includes an adhesive resin layer (B) on the second surface 10B side of the base layer 10 opposite the first surface 10A. The adhesive resin layer (B) is preferably a layer whose adhesive strength decreases in response to an external stimulus, so that the adhesive film 50 can be easily peeled off from the supporting substrate by applying an external stimulus. Here, examples of the adhesive resin layer (B) whose adhesive strength is reduced by an external stimulus include a heat-peeling type adhesive resin layer whose adhesive strength is reduced by heating, a light-peeling type adhesive resin layer whose adhesive strength is reduced by light such as radiation, etc. That is, examples of the external stimulus include light energy and heat energy, etc. Examples of the heat-peelable adhesive resin layer include adhesive resin layers composed of a heat-expandable adhesive that contains an adhesive resin (B1) and further contains a gas-generating component, a heat-expandable adhesive that contains heat-expandable microspheres that can expand to reduce adhesive strength, and a heat-expandable adhesive whose adhesive strength is reduced as a result of the adhesive component undergoing a crosslinking reaction due to heat.

[0071] In this embodiment, the thermally expandable adhesive used in the adhesive resin layer (B) is an adhesive whose adhesive strength is reduced or lost when heated, for example, above 150° C., preferably above 170° C. For example, a material can be selected that does not peel off at 150° C. or below or 170° C. or below, but peels off at 150° C. or above 170° C., and it is preferable that the adhesive film 50 has an adhesive strength sufficient to prevent it from peeling off from the supporting substrate during the manufacturing process of the electronic device. Here, the decrease or loss of adhesive strength due to heating at over 150°C or over 170°C can be evaluated by, for example, attaching the adhesive resin layer (B) side to a stainless steel plate, performing a heat treatment at 140°C for 1 hour, and then heating at a temperature above 150°C or over 170°C for 2 minutes, and then measuring the peel strength from the stainless steel plate. The specific heating temperature when heating at a temperature above 150°C or over 170°C is set to a temperature higher than the temperature at which gas is generated or the temperature at which the thermally expandable microspheres thermally expand, and is appropriately set depending on the type of gas generated or the type of thermally expandable microspheres. In this embodiment, the loss of adhesive strength refers to, for example, a case where the 180° peel strength measured under conditions of 23°C and a tensile speed of 300 mm / min is less than 0.5 N / 25 mm.

[0072] Examples of gas generating components that can be used in the thermal expansion type pressure sensitive adhesive include azo compounds, azide compounds, and Meldrum's acid derivatives. In addition, inorganic foaming agents such as ammonium carbonate, ammonium hydrogen carbonate, sodium hydrogen carbonate, ammonium nitrite, sodium boron hydroxide, and various azides, water, fluorinated alkane compounds such as trichloromonofluoromethane and dichloromonofluoromethane, azo compounds such as azobisisobutyronitrile, azodicarbonamide, and barium azodicarboxylate, paratoluenesulfonylhydrazide, diphenylsulfone-3,3'-disulfonylhydrazide, 4,4'-oxybis(benzenesulfonyl)hydrazide, and the like can be used. Also usable are organic foaming agents such as hydrazine compounds such as p-toluenesulfonylsemicarbazide and 4,4'-oxybis(benzenesulfonylsemicarbazide); triazole compounds such as 5-morpholyl-1,2,3,4-thiatriazole; and N-nitroso compounds such as N,N'-dinitrosopentamethylenetetramine and N,N'-dimethyl-N,N'-dinitrosoterephthalamide. The gas generating component may be added to the adhesive resin (B1) or may be directly bonded to the adhesive resin (B1).

[0073] As the heat-expandable microspheres used in the heat-expandable pressure-sensitive adhesive, for example, a microencapsulated foaming agent can be used. Examples of such heat-expandable microspheres include microspheres in which a substance that is easily gasified and expanded by heating, such as isobutane, propane, or pentane, is encapsulated in an elastic shell. Examples of materials constituting the shell include vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, and polysulfone. Heat-expandable microspheres can be produced, for example, by a coacervation method or an interfacial polymerization method. Thermally expandable microspheres can be added to the adhesive resin.

[0074] The content of at least one selected from the gas-generating component and the heat-expandable microspheres can be appropriately set depending on the expansion ratio and adhesive strength reduction of the heat-peelable adhesive resin layer (B) and is not particularly limited, but is, for example, 1 part by mass or more and 150 parts by mass or less, preferably 10 parts by mass or more and 130 parts by mass or less, and more preferably 12 parts by mass or more and 100 parts by mass or less, relative to 100 parts by mass of the adhesive resin (B1) in the heat-peelable adhesive resin layer (B). It is preferable to design the temperature at which gas is generated or the temperature at which the heat-expandable microspheres expand is greater than 150°C or greater than 170°C.

[0075] Examples of the adhesive resin (B1) constituting the thermally expandable adhesive include (meth)acrylic resin (b), urethane resin, silicone resin, polyolefin resin, polyester resin, polyamide resin, fluorine resin, styrene-diene block copolymer resin, etc. Among these, (meth)acrylic resin (b) is preferred.

[0076] The (meth)acrylic resin (b) used in the adhesive resin layer (B) may be, for example, a copolymer containing a (meth)acrylic acid alkyl ester monomer unit (b1) and a monomer unit (b2) having a functional group capable of reacting with a crosslinking agent. In this embodiment, the (meth)acrylic acid alkyl ester means an acrylic acid alkyl ester, a methacrylic acid alkyl ester, or a mixture thereof.

[0077] The (meth)acrylic adhesive resin (b) according to this embodiment can be obtained, for example, by copolymerizing a monomer mixture containing a (meth)acrylic acid alkyl ester monomer (b1) and a monomer (b2) having a functional group capable of reacting with a crosslinking agent.

[0078] Examples of the monomer (b1) forming the (meth)acrylic acid alkyl ester monomer unit (b1) include (meth)acrylic acid alkyl esters having an alkyl group with about 1 to 12 carbon atoms. Preferred are (meth)acrylic acid alkyl esters having an alkyl group with 1 to 8 carbon atoms. Specific examples include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, and 2-ethylhexyl methacrylate. These may be used alone or in combination of two or more. In the (meth)acrylic adhesive resin (b) according to this embodiment, the content of the (meth)acrylic acid alkyl ester monomer unit (b1) is preferably from 10 mass% to 98.9 mass%, more preferably from 50 mass% to 97 mass%, and even more preferably from 85 mass% to 95 mass%, when the sum of all monomer units in the (meth)acrylic adhesive resin (b) is 100 mass%.

[0079] Examples of the monomer (b2) that forms the monomer (b2) having a functional group that can react with a crosslinking agent include acrylic acid, methacrylic acid, itaconic acid, mesaconic acid, citraconic acid, fumaric acid, maleic acid, itaconic acid monoalkyl ester, mesaconic acid monoalkyl ester, citraconic acid monoalkyl ester, fumaric acid monoalkyl ester, maleic acid monoalkyl ester, glycidyl acrylate, glycidyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide, methacrylamide, tertiary-butylaminoethyl acrylate, and tertiary-butylaminoethyl methacrylate. Preferred are acrylic acid, methacrylic acid, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide, methacrylamide, and the like. These may be used alone or in combination of two or more. In the (meth)acrylic adhesive resin (b) according to this embodiment, the content of the monomer unit (b2) is preferably from 1 to 40% by mass, more preferably from 1 to 20% by mass, and even more preferably from 1 to 10% by mass, when the sum of all monomer units in the (meth)acrylic adhesive resin (b) is taken as 100% by mass.

[0080] The (meth)acrylic adhesive resin (b) according to this embodiment may further contain, in addition to the monomer unit (b1) and the monomer unit (b2), a bifunctional monomer unit (b3) or a specific comonomer unit having surfactant properties (hereinafter referred to as a polymerizable surfactant). The polymerizable surfactant has the property of copolymerizing with the monomers (b1), (b2) and (b3), and also acts as an emulsifier in the case of emulsion polymerization.

[0081] Examples of the monomer (b3) forming the bifunctional monomer unit (b3) include allyl methacrylate, allyl acrylate, divinylbenzene, vinyl methacrylate, vinyl acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tetraethylene glycol di(meth)acrylate, and, for example, those having diacrylate or dimethacrylate at both ends and a main chain structure of propylene glycol type (e.g., manufactured by Nippon Oil & Fats Corporation; trade names: PDP-200, PDP-400, ADP-200, ADP-400), tetramethylene glycol type (e.g., manufactured by Nippon Oil & Fats Corporation; trade names: ADT-250, ADT-850), and mixtures thereof (e.g., manufactured by Nippon Oil & Fats Corporation; trade names: ADET-1800, ADPT-4000).

[0082] In the (meth)acrylic adhesive resin (b) according to this embodiment, the content of the monomer unit (b3) is preferably from 0.1 to 30% by mass, more preferably from 0.1 to 20% by mass, even more preferably from 0.1 to 15% by mass, and particularly preferably from 0.1 to 5% by mass, when the sum of all monomer units in the (meth)acrylic adhesive resin (b) is 100% by mass.

[0083] Examples of polymerizable surfactants include those in which a polymerizable 1-propenyl group has been introduced into the benzene ring of polyoxyethylene nonylphenyl ether (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.; trade names: Aqualon RN-10, RN-20, RN-30, RN-50, etc.), those in which a polymerizable 1-propenyl group has been introduced into the benzene ring of an ammonium salt of a sulfate ester of polyoxyethylene nonylphenyl ether (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.; trade names: Aqualon HS-10, HS-20, HS-1025, etc.), and sulfosuccinic acid diesters having a polymerizable double bond in the molecule (manufactured by Kao Corporation; trade names: Latemul S-120A, S-180A, etc.). In the (meth)acrylic adhesive resin (b) according to this embodiment, the content of the polymerizable surfactant is preferably from 0.1% by mass to 30% by mass, more preferably from 0.1% by mass to 20% by mass, even more preferably from 0.1% by mass to 15% by mass, and particularly preferably from 0.1% by mass to 5% by mass, when the sum of all monomer units in the (meth)acrylic adhesive resin (b) is taken as 100% by mass.

[0084] The (meth)acrylic adhesive resin (b) according to this embodiment may further contain, if necessary, a monomer unit formed from a monomer having a polymerizable double bond, such as vinyl acetate, acrylonitrile, or styrene.

[0085] The polymerization reaction mechanism of the (meth)acrylic adhesive resin (b) according to the present embodiment may be radical polymerization, anionic polymerization, cationic polymerization, etc. Considering the production cost of the (meth)acrylic adhesive resin (b), the effect of the functional group of the monomer, the effect of ions on the surface of the electronic component, etc., it is preferable to polymerize by radical polymerization. When polymerizing by radical polymerization reaction, the following radical polymerization initiators are used: 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 Examples of the peroxides include organic peroxides such as 2-ethylhexanoate, t-butylperoxy-3,5,5-trimethylhexanoate, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, t-butyl peroxide, and di-t-amyl peroxide; inorganic peroxides such as ammonium persulfate, potassium persulfate, and sodium persulfate; and azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, and 4,4'-azobis-4-cyanovaleric acid.

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

[0087] The adhesive resin layer (B) according to this embodiment preferably further contains, in addition to the adhesive resin (B1), a crosslinking agent (B2) having two or more crosslinkable functional groups in one molecule. The crosslinking agent (B2) having two or more crosslinkable functional groups in one molecule is used to react with the functional groups of the adhesive resin (B1) to adjust the adhesive strength and cohesive strength. Examples of such crosslinking agents (B2) include epoxy compounds such as sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, neopentyl glycol diglycidyl ether, and resorcin diglycidyl ether; isocyanate compounds such as tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate triadduct of trimethylolpropane, polyisocyanate, diphenylmethane diisocyanate, and tolylene diisocyanate; and trimethylolpropane-tri-β-aziridinylpropionate. aziridine-based compounds such as N,N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide), N,N'-hexamethylene-1,6-bis(1-aziridinecarboxamide), N,N'-toluene-2,4-bis(1-aziridinecarboxamide), and trimethylolpropane-tri-β-(2-methylaziridine)propionate; tetrafunctional epoxy-based compounds such as N,N,N',N'-tetraglycidyl-m-xylylenediamine and 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane; and melamine-based compounds such as hexamethoxymethylolmelamine. These may be used alone or in combination of two or more. Among these, it is preferable to contain one or more compounds selected from the group consisting of epoxy compounds, isocyanate compounds, and aziridine compounds.

[0088] The content of the crosslinking agent (B2) is usually preferably within a range in which the number of functional groups in the crosslinking agent (B2) is not greater than the number of functional groups in the adhesive resin (B1). However, if necessary, an excess of the crosslinking agent (B2) may be contained when new functional groups are generated by the crosslinking reaction or when the crosslinking reaction is slow. The content of the crosslinking agent (B2) in the adhesive resin layer (B) is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass, per 100 parts by mass of the adhesive resin (B1).

[0089] The adhesive resin layer (B) according to the present embodiment preferably contains a tackifier resin in addition to the adhesive resin (B1) from the viewpoint of improving adhesion to the support substrate. It is preferable to include a tackifier resin in the adhesive resin layer (B) because it is easy to adjust the adhesion to the support substrate at around room temperature. The tackifier resin is preferably one whose softening point is 100°C or higher. Specific examples of the tackifier resin include rosin-based resins such as rosin-based derivatives treated by 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; hydrogenated, disproportionated, polymerized, maleated, and petroleum resins of these natural rosins; coumarone-indene resins, etc.

[0090] Among these, those having a softening point in the range of 100 to 160° C. are more preferred, and those having a softening point in the range of 120 to 150° C. are particularly preferred. By using a tackifier resin having a softening point in the above range, not only is contamination and adhesive residue on the support substrate reduced, but the adhesion to the support substrate in the working environment can be further improved. Furthermore, by using a polymerized rosin ester-based tackifier resin as the tackifier resin, not only is contamination and adhesive residue on the support substrate reduced, but the adhesion to the support substrate in an environment of 80 to 130° C. is improved, and in the case of a heat-expandable pressure-sensitive adhesive containing heat-expandable microspheres, the heat-expandable microspheres can be more easily peeled off from the support substrate after expansion.

[0091] The blending ratio of the tackifier resin is not particularly limited, and may be appropriately selected so that the elastic modulus of the adhesive resin layer (B) can be adjusted within a desired predetermined numerical range. However, in terms of the elastic modulus and initial peeling force of the adhesive resin layer (B), it is preferable to set it to 1 to 100 parts by mass with respect to 100 parts by mass of the adhesive resin (B1). When the blending ratio of the tackifier resin is equal to or more than the above lower limit with respect to 100 parts by mass of the adhesive resin (B1), the adhesion to the support substrate during operation tends to be good. On the other hand, when it is equal to or less than the above upper limit, the attachment to the support substrate at room temperature tends to be good. In terms of the adhesion to the support substrate and the attachment at room temperature, it is more preferable to set the blending ratio of the tackifier resin to 2 to 50 parts by mass with respect to 100 parts by mass of the adhesive resin (B1). In addition, the acid value of the tackifier resin is preferably 30 or less. When the acid value of the tackifier resin is equal to or less than the above upper limit, adhesive residue tends to be less likely to be left on the support substrate during peeling.

[0092] The adhesive resin layer (B) may contain additives such as plasticizers as other components. The total content of the adhesive resin (B1), crosslinking agent (B2) and tackifier resin in the adhesive resin layer (B) is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more, when the entire adhesive resin layer (B) is taken as 100% by mass. Furthermore, when the adhesive resin layer (B) is composed of a heat-expandable adhesive, the total content of the adhesive resin (B1), crosslinking agent (B2), tackifier resin, gas-generating component and heat-expandable microspheres in the adhesive resin layer (B) is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more, when the entire adhesive resin layer (B) is taken as 100% by mass.

[0093] The adhesive resin layer (B) may be a single layer or a multilayer. For example, by laminating two or more layers having different degrees of expansion by heating to form the adhesive resin layer (B), the adhesiveness / thermal peelability can be changed between one side and the other side of the adhesive resin layer (B). The thickness of the adhesive resin layer (B) is not particularly limited, but is preferably, for example, from 3 μm to 300 μm, and more preferably from 20 μm to 150 μm.

[0094] The adhesive resin layer (B) can be formed, for example, by a method of applying an adhesive coating liquid onto the base layer 10, or by transferring the adhesive resin layer (B) formed on a separator onto the base layer 10. The adhesive coating liquid can be coated by a conventional coating method such as a roll coater method, a reverse roll coater method, a gravure roll method, a bar coat method, a comma coater method, a die coater method, etc. There is no particular restriction on the drying conditions of the coated adhesive, but it is generally preferable to dry the coated adhesive at a temperature range of 80 to 200°C for 10 seconds to 10 minutes. More preferably, the coated adhesive is dried at 80 to 170°C for 15 seconds to 5 minutes. In order to sufficiently promote the crosslinking reaction between the crosslinking agent and the adhesive, the coated adhesive may be heated at 40 to 80°C for about 5 to 300 hours after drying of the adhesive coating liquid is completed. The base material layer 10 and the adhesive resin layer (B) may be formed by co-extrusion molding, or the base material layer 10 in the form of a film and the adhesive resin layer (B) in the form of a film may be laminated together.

[0095] <Roughness-absorbing resin layer (C)> The adhesive film 50 of this embodiment has an unevenness-absorbing resin layer (C) that can be crosslinked by light energy and thermal energy between the base layer 10 and the adhesive resin layer (A) or between the base layer 10 and the adhesive resin layer (B). The unevenness-absorbing resin layer (C) is a layer provided for the purpose of improving the conformability of the adhesive film 50 to the surface of the electronic component on which the uneven structure is formed, and improving the adhesion between the electronic component having the uneven structure and the adhesive film 50. Furthermore, the unevenness-absorbing resin layer (C) can be crosslinked and cured by light energy and thermal energy to increase the elastic modulus of the unevenness-absorbing resin layer (C). This makes it possible to prevent the electronic component from sinking into the adhesive film during the sealing process of the electronic component.

[0096] The resin constituting the unevenness-absorbing resin layer (C) is not particularly limited as long as it exhibits unevenness-absorbing properties, and is preferably, for example, a thermoplastic resin. Specifically, one or more selected from the group consisting of polyolefin-based resins, polystyrene-based resins, and (meth)acrylic resins are more preferable. From another perspective, the resin is preferably one having a Shore D hardness of 50 or less, more preferably 40 or less according to ASTM D-2240 Shore D hardness. Even when the resin constituting the irregularity-absorbing resin layer (C) is not a thermoplastic resin, it is preferable that the resin has the same irregularity-absorbing properties as described above.

[0097] The unevenness-absorbing resin layer (C) preferably contains a resin, a crosslinking agent, a photoinitiator that generates active chemical species by light, and a thermal initiator that generates active chemical species by heat. By containing these components in the unevenness-absorbing resin layer (C), the unevenness-absorbing resin layer (C) can be crosslinked more effectively by light energy and thermal energy, and the elastic modulus of the unevenness-absorbing resin layer (C) can be further improved. This makes it possible to suppress the unevenness-absorbing resin layer from being softened by heat in the process of sealing the electronic components with a sealing material, and as a result, it is possible to further suppress the electronic components from sinking into the adhesive film 50 due to the pressure of the sealing material. Depending on the chemical structure and reactivity of the resin and crosslinking agent, the unevenness-absorbing resin layer (C) may be crosslinked (cured) by light energy and thermal energy even if it does not necessarily contain an initiator.

[0098] The resin that can be used to form the irregularity-absorbing resin layer (C) is not particularly limited, but preferable examples include the resins described above as the adhesive resin (B1) in the adhesive resin layer (B). Other resins that can be used to form the unevenness-absorbing resin layer (C) are not particularly limited, and examples thereof include olefin resins such as ethylene-α-olefin copolymers containing ethylene and an α-olefin having 3 to 20 carbon atoms, high-density ethylene resins, low-density ethylene resins, medium-density ethylene resins, very low-density ethylene resins, linear low-density polyethylene (LLDPE) resins, propylene (co)polymers, 1-butene (co)polymers, 4-methylpentene-1 (co)polymers, ethylene-cyclic olefin copolymers, ethylene-α-olefin-cyclic olefin copolymers, ethylene-α-olefin-non-conjugated polyene copolymers, ethylene-α-olefin-conjugated polyene copolymers, ethylene-aromatic vinyl copolymers, and ethylene-α-olefin-aromatic vinyl copolymers; ethylene-carboxylic acid anhydride copolymers such as ethylene-unsaturated carboxylic anhydride copolymers and ethylene-α-olefin-unsaturated carboxylic anhydride copolymers; ethylene-epoxy copolymers such as ethylene-epoxy-containing unsaturated compound copolymers and ethylene-α-olefin-epoxy-containing unsaturated compound copolymers; ethylene-(meth)ethyl acrylate copolymers, ethylene-(meth)ethyl acrylate copolymers, ) methyl acrylate copolymer, ethylene-propyl (meth)acrylate copolymer, ethylene-butyl (meth)acrylate copolymer, ethylene-hexyl (meth)acrylate copolymer, ethylene-2-hydroxyethyl (meth)acrylate copolymer, ethylene-2-hydroxypropyl (meth)acrylate copolymer, ethylene-glycidyl (meth)acrylate copolymer, etc.; ethylene-ethylenically unsaturated acid copolymers such as ethylene-(meth)acrylic acid copolymer, ethylene-maleic acid copolymer, ethylene-fumaric acid copolymer, ethylene-crotonic acid copolymer, etc.; ethylene-vinyl acetate copolymer, ethylene-vinyl propionate copolymer, ethylene-vinyl butyrate copolymer, ethylene-vinyl stearate copolymer, etc.; ethylene-styrene copolymer, etc.; unsaturated carboxylic acid ester (co)polymers such as (meth)acrylic acid ester (co)polymers; ionomer resins such as ethylene-metal acrylate copolymer, ethylene-metal methacrylate copolymer; urethane-based resins; silicone-based resins; acrylic acid-based resins; methacrylic acid-based resins;Cyclic olefin (co)polymers; α-olefins, aromatic vinyl compounds, aromatic polyene copolymers; ethylene, α-olefins, aromatic vinyl compounds; aromatic polyene copolymers; ethylene, aromatic vinyl compounds, aromatic polyene copolymers; styrene-based resins; acrylonitrile, butadiene, styrene copolymers; styrene, conjugated diene copolymers; acrylonitrile, styrene copolymers; acrylonitrile, ethylene, α-olefins, non-conjugated polyene, styrene copolymers; acrylonitrile, ethylene, α-olefins, conjugated polyene, styrene copolymers; methacrylic acid, styrene copolymers; ethylene terephthalate resins; fluororesins; polyester carbonates; polyvinyl chloride; polyvinylidene chloride; polyolefin-based thermoplastic elastomers; polystyrene-based thermoplastic elastomers; polyurethane-based thermoplastic elastomers; 1,2-polybutadiene-based thermoplastic elastomers; trans-polyisoprene-based thermoplastic elastomers; chlorinated polyethylene-based thermoplastic elastomers; liquid crystal polyesters; polylactic acid, etc., may be used. ; The irregularity-absorbing resin layer (C) may contain only one resin, or may contain two or more resins.

[0099] The crosslinking agent that can be contained in the unevenness-absorbing resin layer (C) is not particularly limited, and may be any agent that undergoes a crosslinking reaction due to a chemical species generated from an initiator. As the preferred crosslinking agent, there can be mentioned polyfunctional (meth)acrylate compounds and isocyanate compounds. More specifically, there can be mentioned urethane (meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butanediol di(meth)acrylate, etc.; and isocyanate compounds such as tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate 3 adduct of trimethylolpropane, polyisocyanate, diphenylmethane diisocyanate, tolylene diisocyanate, etc. Examples of the crosslinking agent include various monomers or oligomers such as urethane-based, polyether-based, polyester-based, polycarbonate-based, and polybutadiene-based. The amount of the crosslinking agent is, for example, 5 parts by mass or more and 500 parts by mass or less, and preferably 40 parts by mass or more and 150 parts by mass or less, relative to 100 parts by mass of the resin (base polymer) such as a (meth)acrylic polymer.

[0100] From another point of view, the unevenness-absorbing resin layer (C) may contain one or more crosslinking agents (A2) that can be contained in the adhesive resin layer (A). Specifically, the unevenness-absorbing resin layer (C) may contain an isocyanate-based compound. When such a crosslinking agent is used, the amount thereof is, for example, 0.01 parts by mass or more and 5 parts by mass or less, preferably 0.01 parts by mass or more and 3 parts by mass or less, relative to 100 parts by mass of the resin (base polymer).

[0101] The photoinitiator that may be contained in the unevenness-absorbing resin layer (C) is not particularly limited as long as it is capable of crosslinking the resin and / or crosslinking agent in the unevenness-absorbing resin layer (C) by light energy. The chemical species generated from the photoinitiator may be appropriately selected based on the functional groups of the resin and / or crosslinker. The chemical species generated from the photoinitiator is typically a radical or a cation.

[0102] As the photoinitiator, an alkylphenone-based photoinitiator, an acetophenone-based photoinitiator, an oxime ester-based photoinitiator, a benzoin ether-based photoinitiator, an acylphosphine oxide-based photoinitiator, an α-ketol-based photoinitiator, an aromatic sulfonyl chloride-based photoinitiator, a photoactive oxime-based photoinitiator, a benzoin-based photoinitiator, a benzyl-based photoinitiator, a benzophenone-based photoinitiator, a thioxanthone-based photoinitiator, etc. can be used. The photoinitiator can be used alone or in appropriate combination of two or more. Among these, it is preferable to include an alkylphenone-based photoinitiator from the viewpoint of high reactivity and low sublimation.

[0103] Specific examples of alkylphenone photoinitiators include 2-benzyl-2-(dimethylamino)-4'-morpholinobutyrophenone, 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-propan-1-one, 2-hydroxy-1-{[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one, and the like. Specific examples of acetophenone-based photoinitiators include 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, methoxyacetophenone, and the like. Specific examples of oxime ester photoinitiators include 1,2-octanedione, 1-[4-(phenylthio)phenyl]-2-(o-benzoyloxime), ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(o-acetyloxime), and the like. Specific examples of benzoin ether photoinitiators include 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. Specific examples of acylphosphine oxide photoinitiators include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2,4-di-n-butoxyphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, and the like. Specific examples of α-ketol photoinitiators include 2-methyl-2-hydroxypropiophenone, 1-[4-(2-hydroxyethyl)phenyl]-2-methylpropan-1-one, and the like. A specific example of the aromatic sulfonyl chloride photoinitiator is 2-naphthalenesulfonyl chloride. Specific examples of photoactive oxime-based photoinitiators include 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime, and the like. Specific examples of benzoin-based photoinitiators include benzoin. Specific examples of benzyl-based photoinitiators include benzyl and the like. Specific examples of benzophenone-based photoinitiators include benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, and α-hydroxycyclohexyl phenyl ketone. Specific examples of thioxanthone-based photoinitiators include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, and dodecylthioxanthone.

[0104] As the photoinitiator, a photoinitiator that absorbs light having a wavelength of 300 nm or more (for example, light having a wavelength of 300 nm or more and 500 nm or less) to generate radicals can be preferably used. The photoinitiator can be used alone or in appropriate combination of two or more kinds.

[0105] The content of the photoinitiator in the roughness-absorbing resin layer (C) is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, and even more preferably 0.5 parts by mass or more, based on 100 parts by mass of the resin (base polymer) such as the (meth)acrylic polymer, etc. From the viewpoint of storage stability, the content is preferably 7 parts by mass or less, and more preferably 3 parts by mass or less.

[0106] The thermal initiator that may be contained in the unevenness-absorbing resin layer (C) is not particularly limited as long as it is capable of crosslinking the resin and / or crosslinking agent in the unevenness-absorbing resin layer (C) 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 crosslinker. The chemical species generated from the thermal initiator is typically a radical or a cation.

[0107] Examples of thermal initiators include 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. These may be used alone or in combination of two or more. Among these, azo compounds and organic peroxides are preferred from the viewpoints of availability and ease of handling, and organic peroxides are more preferred.

[0108] Commercially available thermal initiators include V-70, V-65, V-601, V-59, V-40, VF-096, V-30, VAm-110, and VAm-111 (all manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), Niper BW, Niper BMT, Peroyl TCP, Peroyl L, Peroyl 355, Peroyl SA, Perhexa HC, Perbutyl 355, Perbutyl D, Perbutyl L, Perbutyl ND, Perocta O, Perhexyl D, Perhexyl O, and Perhexyl PV (all manufactured by NOF Corp.), Trigonox 36-C75, Laurox, Perkadox L-W75, Perkadox CH-50L, Trigonox TMBH, Kayacumene H, Kayabutyl H-70, Perkadox BC-FF, and Kayahexyl PV (all manufactured by NOF Corp.). Examples of such compounds include SA AD, Perkadox 14, Kayabutyl C, Kayabutyl D, Perkadox 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, Kayacarvone EH, Kayacarvone I-20, Kayacarvone BIC-75, Trigonox 117, and Kayalene 6-70 (all manufactured by Kayaku Akzo Co., Ltd.).

[0109] The content of the thermal initiator in the roughness-absorbing resin layer (C) is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, and even more preferably 0.5 parts by mass or more, based on 100 parts by mass of the resin (base polymer) such as the (meth)acrylic polymer, etc. From the viewpoint of storage stability, the content is preferably 7 parts by mass or less, and more preferably 3 parts by mass or less.

[0110] In the pressure-sensitive adhesive film 50 according to the present embodiment, the lower limit of the storage modulus E' at 60°C of the unevenness-absorbing resin layer (C) before crosslinking is 1.0 × 10 3 Pa or more is preferable, 5.0×10 3 Pa or more is more preferable. In addition, in the pressure-sensitive adhesive film 50 according to this embodiment, the upper limit of the storage elastic modulus E' at 60°C of the unevenness-absorbing resin layer (C) before crosslinking is 1.0 × 10 in order to effectively absorb the unevenness of the chip surface and to prevent the unevenness absorption from deteriorating over time due to springback of the resin. 6 Pa or less is preferable, and 5.0×10 5 Pa or less is more preferable. The storage modulus E' at 60°C of the unevenness-absorbing resin layer (C) before crosslinking can be controlled within the above range, for example, by controlling the types and blending ratios of each component constituting the unevenness-absorbing resin layer (C).

[0111] In the pressure-sensitive adhesive film 50 according to the present embodiment, the lower limit of the storage modulus E' at 125°C of the unevenness-absorbing resin layer (C') obtained by crosslinking the unevenness-absorbing resin layer (C) is 1.0 × 10 6 Pa or more is preferable, 5.0×10 6 Pa or more is more preferable. In the pressure-sensitive adhesive film 50 according to the present embodiment, the upper limit of the storage modulus E' at 125°C of the irregularity-absorbing resin layer (C') is 1.0 x 10 9 Pa or less is preferable, and 1.0×10 8 Pa or less is more preferable. The storage modulus E' of the unevenness-absorbing resin layer (C') at 125°C can be controlled within the above range, for example, by controlling the types and blending ratios of each component constituting the unevenness-absorbing resin layer (C). Here, whether the crosslinking treatment of the unevenness-absorbing resin layer (C) is completed can be determined, for example, by determining the point at which the storage modulus E' of the unevenness-absorbing resin layer (C) no longer increases even after the crosslinking treatment.

[0112] The thickness of the unevenness-absorbing resin layer (C) is not particularly limited as long as it is a thickness that can embed the uneven structure of the electronic component, but for example, it is preferably 5 μm or more and 1000 μm or less, more preferably 20 μm or more and 900 μm or less, even more preferably 30 μm or more and 800 μm or less, and particularly preferably 50 μm or more and 700 μm or less.

[0113] Here, the uneven structure of the electronic component preferably includes a bump electrode. When the uneven structure of the electronic component includes a bump electrode, when the height of the bump electrode is H [μm] and the thickness of the unevenness-absorbing resin layer (C) is d [μm], 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 equal to or less than the upper limit, the thickness of the adhesive film 50 can be made thinner while improving the unevenness absorption. The lower limit of H / d is not particularly limited, but is, for example, equal to or greater than 0.01.The height of the bump electrode is generally equal to or greater than 2 μm and equal to or less than 600 μm.

[0114] The method for forming the irregularity-absorbing resin layer (C) is not particularly limited, and the same method as that for the adhesive resin layer (A) and the adhesive resin layer (B) can be used.

[0115] <Other layers> The adhesive film 50 according to this embodiment may further include, for example, an easy-adhesion layer or the like between each of the layers, as long as the effect of this embodiment is not impaired.

[0116] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than those described above can also be adopted.

[0117] The present invention is not limited to the above-described embodiment, and modifications and improvements within the scope of the present invention that can achieve the object of the present invention are included in the present invention. EXAMPLES

[0118] The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. The details of the method for producing the adhesive film are as follows.

[0119] <Synthesis (polymerization) of adhesive raw materials for forming the unevenness-absorbing resin layer (C), adhesive resin layer (A) or adhesive resin layer (B)>

[0120] (Meth)acrylic resin solution 1: 49 parts by mass of ethyl acrylate, 20 parts by mass of 2-ethylhexyl acrylate, 21 parts by mass of methyl acrylate, 10 parts by mass of glycidyl methacrylate, and 0.5 parts by mass of a benzoyl peroxide-based polymerization initiator (solid content equivalent) were reacted in 65 parts by mass of toluene and 50 parts by mass of ethyl acetate at 80° C. for 10 hours. After the reaction was completed, the resulting solution was cooled, and 25 parts by mass of xylene, 5 parts by mass of acrylic acid, and 0.5 parts by mass of tetradecyl dimethyl benzyl ammonium chloride were added to the cooled solution, and the reaction was carried out at 85° C. for 32 hours while blowing in air. In this way, a (meth)acrylic resin solution 1 was obtained.

[0121] (Meth)acrylic resin emulsion 1: Using 0.5 parts by mass of ammonium peroxodisulfate as a polymerization initiator, 63 parts by mass of 2-ethylhexyl acrylate, 21 parts by mass of n-butyl acrylate, 9 parts by mass of methyl methacrylate, 3 parts by mass of 2-hydroxyethyl methacrylate, 2 parts by mass of methacrylic acid, 1 part by mass of acrylamide, 1 part by mass of polytetramethylene glycol diacrylate (manufactured by NOF Corporation, product name: Blemmer ADT-250), and 2 parts by mass of an aqueous solution of polyoxyethylene nonylpropenyl phenyl ether ammonium sulfate (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name: Aqualon HS-1025) were emulsion polymerized in deionized water at 70° C. for 8 hours. After the polymerization was completed, the pH was adjusted to 7 with aqueous ammonia. In this manner, a (meth)acrylic resin emulsion 1 having a solid content concentration of 56.5% was obtained.

[0122] (Meth)acrylic resin emulsion 2: Using 0.5 parts by mass of 4,4'-azobis-4-cyanovaleric acid (manufactured by Otsuka Chemical Co., Ltd., product name: ACVA) as a polymerization initiator, 74 parts by mass of butyl acrylate, 14 parts by mass of methyl methacrylate, 9 parts by mass of 2-hydroxyethyl methacrylate, 2 parts by mass of methacrylic acid, 1 part by mass of acrylamide, and 3 parts by mass of an aqueous solution of polyoxyethylene nonylpropenyl phenyl ether ammonium sulfate (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name: Aqualon HS-1025) were emulsion polymerized in deionized water at 70°C for 8 hours. After the polymerization was completed, the pH was adjusted to 7 with aqueous ammonia. As a result of the above, a (meth)acrylic resin emulsion 2 having a solid content concentration of 42.5% was obtained.

[0123] <Adhesive coating solution composition> Adhesive coating solution B1 for forming adhesive resin layer (B): 100 parts by mass of (meth)acrylic resin solution 1 (solid content concentration 45%) and 0.9 parts by mass of an isocyanate crosslinking agent (manufactured by Mitsui Chemicals, Inc., product name: Takenate D170N) (2 parts by mass per 100 parts by mass of adhesive resin in solid content equivalent) were mixed, and 7 parts by mass of toluene and 7 parts by mass of ethyl acetate were added to prepare adhesive coating solution B1.

[0124] Adhesive coating solution B2 for forming adhesive resin layer (B): 100 parts by mass of the (meth)acrylic resin solution 1 (solid content concentration 45%), 2.4 parts by mass of a polymerized rosin ester tackifier (manufactured by Arakawa Chemical Industries, Ltd., product name: Pencel D-125) (5.3 parts by mass per 100 parts by mass of adhesive resin in terms of solid content), 1.3 parts by mass of an isocyanate crosslinking agent (manufactured by Mitsui Chemicals, Inc., product name: Olester P49-75S) (3.7 parts by mass per 100 parts by mass of adhesive resin in terms of solid content), and 7.1 parts by mass of thermally expandable microspheres (manufactured by Sekisui Chemical Co., Ltd., product name: Advancell EM-503) (15.8 parts by mass per 100 parts by mass of adhesive resin in terms of solid content) were mixed, and 37 parts by mass of toluene and 37 parts by mass of ethyl acetate were added to prepare an adhesive coating solution B2.

[0125] Adhesive coating solution C1 for forming the unevenness-absorbing resin layer (C): (Meth)acrylic resin solution 1, an isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals, Inc., product name: Olester P49-75S), a thermal initiator (manufactured by Nouryon Chemical, Inc., organic peroxide, product name: Perkadox 12-XL25), an alkylphenone-based photoinitiator (manufactured by IGM Resins BV, 2-benzyl-2-(dimethylamino)-4'-morpholinobutyrophenone, product name: Omnirad369), and a multifunctional acrylic oligomer (manufactured by Toa Gosei Co., Ltd., product name: Aronix M400) were mixed in the solid content blending ratio (parts by mass) shown in Table 1 to prepare adhesive coating solution C1.

[0126] Adhesive coating solution C2 for forming the unevenness-absorbing resin layer (C): The (meth)acrylic resin solution 1, an isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals, Inc., product name: Olester P49-75S), a thermal initiator (manufactured by Nouryon Chemical Industries, Ltd., organic peroxide, product name: Perkadox 12-XL25) and a multifunctional acrylic oligomer (manufactured by Toa Gosei Co., Ltd., product name: Aronix M400) were mixed in the solid content blending ratio (parts by mass) shown in Table 1 to prepare adhesive coating solution C2.

[0127] Adhesive coating solution A for forming adhesive resin layer (A): As shown in Table 1, 42.6 parts by mass of (meth)acrylic resin emulsion 1, 57.4 parts by mass of (meth)acrylic resin emulsion 2, 0.4 parts by mass of dimethylethanolamine, 5 parts by mass of an epoxy compound (product name: EX-1610, manufactured by Nagase ChemteX Corporation) serving as a crosslinking agent, 13 parts by mass of diethylene glycol monobutyl ether, and 20 parts by mass of HO were mixed to prepare adhesive coating solution A.

[0128] <Preparation of adhesive film> [Example 1] First, the adhesive coating solution B1 was applied onto a separator that had been subjected to a silicone release treatment, and dried for 3 minutes at 120° C. to form a resin film. This resin film was then attached to the second surface of a polyethylene terephthalate film (manufactured by Toray Industries, Inc., product name: Lumirror S10, thickness: 38 μm, double-sided corona treated product) that was a base layer, to form an acrylic resin layer. Similarly, the adhesive coating solution B2 was applied onto the separator and dried at 120° C. for 3 minutes to form a resin film. This resin film was then laminated onto the acrylic resin layer, thereby obtaining a two-layer adhesive resin layer (B). Thereafter, the adhesive coating solution C1 was similarly applied onto the separator and dried at 100°C for 3 minutes to form a resin film. This resin film was attached to the first surface of the substrate layer (the surface of the substrate layer opposite to the surface on which the adhesive resin layer (B) was provided). This resulted in a crosslinked irregularity-absorbing resin layer (C). Furthermore, the adhesive coating solution A was applied onto the separator and dried at 120° C. for 3 minutes to form a resin film. This resin film was laminated onto the crosslinked irregularity-absorbing resin layer (C) described above. This produced an adhesive resin layer (A). As a result of the above, an adhesive film was obtained comprising a base layer, an adhesive resin layer (A) provided on the first surface side of the base layer, an adhesive resin layer (B) provided on the second surface side of the base layer, and an unevenness-absorbing resin layer (C) provided between the base layer and the adhesive resin layer (A). The resulting adhesive film was heated at 60° C. for 5 days.

[0129] [Comparative Example 1] An adhesive film was obtained in the same manner as in Example 1, except that the adhesive coating liquid C2 was used instead of the adhesive coating liquid C1 for forming the irregularity-absorbing resin layer (C). (The material for forming the adhesive resin layer (B) and the method for providing the adhesive resin layer (B) are the same in Example 1 and Comparative Example 1.) Incidentally, Comparative Example 1 differs from Example 1 in that the irregularity-absorbing resin layer does not contain an alkylphenone-based photoinitiator (Omnirad369) and is not crosslinkable by light energy.

[0130] <Evaluation> (1) Measurement of storage modulus E' at 125°C of uneven absorbent resin layer (C) Using the adhesive coating solutions C1 and C2 for forming the unevenness-absorbing resin layer (C) used in the examples and comparative examples, unevenness-absorbing resin layers (C) having a thickness of 40 μm were prepared separately from the adhesive film. Then, the obtained unevenness-absorbing resin layers (C) were laminated to obtain unevenness-absorbing resin layer samples C1S and C2S having a thickness of 1 mm. For the obtained unevenness-absorbing resin layer samples C1S and C2S, 1080 mJ / cm 2The structure was then irradiated with UV light of 300 to 600 nm wavelength using a UV irradiator (Ushio Inc., product name: UVX-02528S1AJA02) under the above conditions. The structure was then heated at 130°C for 30 minutes. As a result, the unevenness-absorbing resin layer (C) was crosslinked (cured), and samples C1S' and C2S' for measuring viscoelasticity of the unevenness-absorbing resin layer (C') were obtained. The solid viscoelasticity of the obtained viscoelasticity measurement samples C1S' and C2S' was measured using a solid viscoelasticity measurement device (RSA-3, manufactured by TA Instruments) under the conditions of a frequency of 1 Hz, a heating rate of 5°C / min, a strain fixed mode of 0.05%, a chuck distance of 20 mm, and a sample width of 10 mm, and the measurement results were analyzed. The storage modulus E' at 125°C of the unevenness-absorbing resin layer (C) was determined.

[0131] (2) Wrinkle evaluation First, the adhesive resin layer (B) side of the adhesive film obtained in the Examples and Comparative Examples was adhered onto a stainless steel plate (φ320 mm, thickness 2.0 mm) for compression molding. Next, 1574 silicon mirror chips of 4.7 mm×3.9 mm and 55 patterned silicon chips of 3.5 mm×3.5 mm were placed as electronic components on the adhesive resin layer (A) of the adhesive film and bonded to each other to obtain a structure. For the resulting structure, 1080 mJ / cm 2 Under the above conditions, UV rays with a wavelength of 300 to 600 nm were irradiated using a UV irradiator (Ushio Inc., product name: UVX-02528S1AJA02). In this case, the UV was irradiated from the side where the silicon chip was attached. The structure was then heated at 130°C for 30 minutes. This caused the unevenness-absorbing resin layer (C) to crosslink (cure).

[0132] Next, the silicon chip on the adhesive resin layer (A) was encapsulated by compression molding (125°C, 400 seconds) using a liquid epoxy resin encapsulant (manufactured by Nagase Chemtex Corporation, product name: R4212-2C) using a compression molding machine. This resulted in a structure in which an encapsulating resin wafer (φ300 mm, thickness 550 μm) was formed on a stainless steel plate. The resulting structure was subjected to post-mold curing at 150° C. for 30 minutes. Thereafter, the adhesive film was peeled off from the stainless steel plate by heating at 190° C. for 60 seconds, and the adhesive film was then peeled off from the sealing resin wafer. The surface unevenness of the obtained sealing resin wafer was observed using a shape analysis laser microscope (manufactured by KEYENCE Corporation, product name: VK-X1000), and wrinkles were evaluated according to the following criteria. ○ (Good): No repeated irregularities with height differences between concave and convex parts of 5 μm or more × (Poor): Repeated irregularities with height differences between concave and convex parts of 5 μm or more

[0133] (3) Evaluation of stand-off of electronic components during the encapsulation process First, the adhesive resin layer (B) side of the adhesive film obtained in the Examples and Comparative Examples was adhered onto a stainless steel plate (φ320 mm, thickness 2.0 mm) for compression molding. Next, 1574 silicon mirror chips of 4.7 mm×3.9 mm and 55 patterned silicon chips of 3.5 mm×3.5 mm were placed as electronic components on the adhesive resin layer (A) of the adhesive film and bonded to each other to obtain a structure. For the resulting structure, 1080 mJ / cm 2 Under the above conditions, UV rays with a wavelength of 300 to 600 nm were irradiated using a UV irradiator (Ushio Inc., product name: UVX-02528S1AJA02). In this case, the UV was irradiated from the side where the silicon chip was attached. The structure was then heated at 130°C for 30 minutes. This caused the unevenness-absorbing resin layer (C) to crosslink (cure).

[0134] Next, the silicon chip on the adhesive resin layer (A) was encapsulated by compression molding (125°C, 400 seconds) using a liquid epoxy resin encapsulant (manufactured by Nagase Chemtex Corporation, product name: R4212-2C) using a compression molding machine. This resulted in a structure in which an encapsulating resin wafer (φ300 mm, thickness 550 μm) was formed on a stainless steel plate. The resulting structure was subjected to post-mold curing at 150° C. for 30 minutes. Thereafter, the adhesive film was peeled off from the stainless steel plate by heating at 190° C. for 60 seconds, and the adhesive film was then peeled off from the sealing resin wafer. For the obtained encapsulating resin wafer, the height of the encapsulating material surface was used as a reference, and the difference between the height of the surface of the silicon chip that was not bonded to the adhesive resin layer (A) and the height of the encapsulating material surface was measured with a laser microscope (Keyence Corporation, product name: VK-X1000) to determine the standoff. The standoff of the electronic component was evaluated based on the average value of the standoffs of five chips according to the following criteria. ○(Good): Standoff is less than 10μm × (bad): Standoff is 10 μm or more

[0135] [Table 1]

[0136] From Table 1, it can be seen that the unevenness-absorbing resin layer (C) can be crosslinked by light energy and thermal energy, and thus it is possible to suppress the occurrence of seal defects and wrinkles in electronic components, which are called standoffs. [Explanation of symbols]

[0137] A Adhesive resin layer B Adhesive resin layer C. Unevenness-absorbing resin layer C' Unevenness-absorbing resin layer 10 Base material layer 10A 1st side 10B 2nd side 50 Adhesive Film 50A Adhesive Film 60 Encapsulating material 60A Sealing material 70 Electronic Components 70A Electronic Components 75 Uneven structure 75A uneven structure 80 Support substrate 80A support board 90 Standoff 100 structures 200 Electronic equipment 300 Electronic equipment 310 wiring layer 320 Bump 400 Electronic equipment

Claims

1. an adhesive film comprising: a base layer; an adhesive resin layer (A) provided on a first surface side of the base layer for temporarily fixing an electronic component; an adhesive resin layer (B) provided on a second surface side of the base layer; and an unevenness-absorbing resin layer (C) provided between the base layer and the adhesive resin layer (A) or between the base layer and the adhesive resin layer (B) and crosslinkable by light energy and thermal energy; an electronic component attached to the adhesive resin layer (A) of the adhesive film and having a concave-convex structure; A preparation step of preparing a structure comprising: a crosslinking step of crosslinking the unevenness-absorbing resin layer (C) in the structure by applying light energy and heat energy to the unevenness-absorbing resin layer (C); a sealing step of sealing the electronic component with a sealing material; A method for manufacturing an electronic device comprising at least the steps of:

2. The crosslinking step comprises: a first crosslinking step of crosslinking the unevenness-absorbing resin layer (C) by irradiating the structure with light; A second crosslinking step of further crosslinking the unevenness-absorbing resin layer (C) by heating the structure; The method for manufacturing an electronic device according to claim 1 , comprising at least the steps of:

3. 3. The method for manufacturing an electronic device according to claim 1, further comprising the steps of: The method for producing an electronic device, wherein the unevenness-absorbing resin layer (C) comprises a resin, a crosslinking agent, a photoinitiator, and a thermal initiator.

4. The method of claim 3 , wherein the photoinitiator comprises an alkylphenone-based photoinitiator.

5. 5. The method for producing an electronic device according to claim 3, 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 a carbon-halogen bond, and azo compounds.

6. 6. The method for manufacturing an electronic device according to claim 1 , The method for manufacturing an electronic device, wherein the uneven structure of the electronic component includes a bump electrode.

7. 7. The method of claim 1, further comprising the steps of: The storage modulus E' at 125°C of the unevenness-absorbing resin layer (C') obtained by crosslinking the unevenness-absorbing resin layer (C) is 1.0 x 10 ６ Pa or more 1.0×10 ９ A method for manufacturing an electronic device, the method comprising the steps of:

8. 8. The method for manufacturing an electronic device according to claim 1 , further comprising the steps of: The method for producing an electronic device, wherein the unevenness-absorbing resin layer (C) has a thickness of 5 μm or more and 1000 μm or less.

9. 9. The method for manufacturing an electronic device according to claim 1 , The method for producing an electronic device further comprises a support substrate on which the structure is attached to the adhesive resin layer (B).

10. 10. The method of claim 9, further comprising the steps of: The method for manufacturing an electronic device further comprises, after the sealing step, a first peeling step of peeling off the support substrate from the structure by applying an external stimulus to reduce the adhesive strength of the adhesive resin layer (B).

11. 11. The method of claim 10, further comprising the steps of: The method for manufacturing an electronic device further comprises, after the first peeling step, a second peeling step of peeling the adhesive film from the electronic component.

12. 12. The method of claim 1, further comprising the steps of: The method for manufacturing an electronic device, wherein the sealing material is an epoxy resin-based sealing material.

13. 13. The method of claim 1, further comprising the steps of: The adhesive resin layer (A) contains an adhesive resin, The method for producing an electronic device, wherein the adhesive resin contains one or more types selected from the group consisting of (meth)acrylic adhesive resins, silicone adhesive resins, urethane adhesive resins, olefin adhesive resins and styrene adhesive resins.

14. a preparation step of preparing a structure including an adhesive film including a base layer, an adhesive resin layer (A) provided on a first surface side of the base layer and for temporarily fixing an electronic component, and an unevenness-absorbing resin layer (C) provided between the base layer and the adhesive resin layer (A) and capable of being crosslinked by light energy and thermal energy, and an electronic component attached to the adhesive resin layer (A) of the adhesive film and having an unevenness structure; a first crosslinking step of crosslinking the unevenness-absorbing resin layer (C) in the structure by irradiating the unevenness-absorbing resin layer (C) with light; A second crosslinking step of further crosslinking the unevenness-absorbing resin layer (C) in the structure by heating the unevenness-absorbing resin layer (C); a sealing step of sealing the electronic component with a sealing material; A method for manufacturing an electronic device comprising at least the steps of:

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