Method of manufacturing electronic devices

Abstract

A method for manufacturing an electronic device, comprising the steps of: preparing a structure (100) including an adhesive film (10) having a base layer (A) and an adhesive resin layer (C), and a workpiece (20) temporarily fixed to the adhesive resin layer (C); and processing the workpiece (20) temporarily fixed to the adhesive resin layer (C), wherein the adhesive resin layer (C) includes thermally expandable microspheres, and the ratio (Ra2 / Ra1) of the arithmetic mean roughness Ra2 of the adhesive film (10) after a predetermined treatment by a predetermined method 2 to the arithmetic mean roughness Ra1 of the adhesive film (10) after a predetermined treatment by a predetermined method 1 is 0.40 or more.

Description

Technical Field

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

Background Art

[0002] In the manufacturing process of an electronic device, as a technique using an adhesive film, for example, the techniques described in Patent Documents 1 to 3 can be cited.

[0003] Patent Document 1 has a laminated structure including a base material and an adhesive layer, and is suitable for suppressing the floating of a semiconductor chip with a dicing tape after dicing on a dicing tape and increasing the separation distance while suppressing the floating of the semiconductor chip with a dicing tape from the dicing tape in an expand process performed using a dicing dicing bond film (DDAF) to obtain a semiconductor chip with a die bond film (DAF). A dicing tape is described, which is suitable for realizing good pick-up properties in the pick-up process, and the ratio value of the second tensile stress generated at a strain value of 20% in a tensile test performed under the conditions of an initial chuck distance of 100 mm, 23 ° C, and a tensile speed of 1000 mm / min for a 20-mm-wide dicing tape test piece to the first tensile stress generated at a strain value of 20% in a tensile test performed under the conditions of an initial chuck distance of 100 mm, 23 ° C, and a tensile speed of 10 mm / min for a 20-mm-wide dicing tape test piece is 1.4 or more.

[0004] Patent Document 2 describes a heat-resistant adhesive sheet for semiconductor device manufacturing, which is used to adhere to substrate-less semiconductor chips when resin encapsulating them, with the aim of solving the problems of the chip not being held in place by the pressure during resin encapsulation and shifting from the designated position, or the package being damaged when peeling off the heat-resistant adhesive sheet for semiconductor device manufacturing due to the hardening of the encapsulating material and strong adhesion to the chip surface due to heat. The heat-resistant adhesive sheet has a base layer and an adhesive layer, and the adhesive layer has an adhesive strength to SUS304 after bonding of 0.5 N / 20 mm or more, and hardens due to the stimuli received by the time the resin encapsulation process is completed, resulting in a package peeling strength of 2.0 N / 20 mm or less.

[0005] Patent Document 3 describes a method for manufacturing an organic EL panel using an ultrathin glass substrate, which aims to provide a method for manufacturing an organic EL panel in which the ultrathin glass substrate does not "crack" or "chip" during the manufacturing process, organic EL elements can be efficiently formed by vacuum deposition, and the organic EL panel can be recovered after the manufacturing process without damaging the ultrathin glass substrate, and there is no need to include a step of cleaning the back surface of the ultrathin glass substrate. The method for manufacturing an organic electroluminescent panel in which organic electroluminescent elements are formed on an ultrathin glass substrate by vacuum deposition involves temporarily fixing the ultrathin glass substrate to a support plate via a double-sided adhesive tape having a heat-release adhesive layer containing thermally expandable microspheres that begin to expand and / or foam at a temperature higher than the vacuum deposition temperature on at least one side of the substrate layer, and forming electrodes on the ultrathin glass substrate.

[0006] Patent Document 4 describes an adhesive sheet that achieves both surface smoothness and thin adhesive layer thickness, resulting in less deformation of the adhesive layer during processing, enabling high-precision processing and significantly improving product characteristics and productivity, and is useful as a support sheet for processing electronic components such as small ceramic capacitors. The objective is to provide an adhesive sheet having an adhesive layer containing thermally expandable microspheres on at least one side of a substrate, or an adhesive layer consisting of a resin layer containing thermally expandable microspheres and an adhesive layer, wherein the adhesive layer is laminated on the side opposite to the substrate of the resin layer, and the thickness of the adhesive layer is 10 to 38 μm, and the maximum particle size of the thermally expandable microspheres is less than or equal to the thickness of the adhesive layer, and the mode diameter is 5 to 30 μm. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2019-16634 [Patent Document 2] Japanese Patent Publication No. 2011-134811 [Patent Document 3] International Publication No. 2010 / 004703 [Patent Document 4] Japanese Patent Publication No. 2008-45011 [Overview of the project] [Problems that the invention aims to solve]

[0008] This invention provides a method for manufacturing an electronic device that can reduce contamination of the target object. [Means for solving the problem]

[0009] According to the present invention, a method for manufacturing an electronic device is provided as shown below. [1] A step of preparing a structure comprising an adhesive film having a base layer (A) and an adhesive resin layer (C), and a workpiece temporarily fixed to the adhesive resin layer (C), The process includes processing the object to be processed which is temporarily fixed to the adhesive resin layer (C), The adhesive resin layer (C) contains thermally expandable microspheres, A method for manufacturing an electronic device, wherein the ratio (Ra2 / Ra1) of the arithmetic mean roughness Ra2 obtained by the following (method 2) after the following (process 1) to the arithmetic mean roughness Ra1 obtained by the following (method 1) after the following (process 1) of the adhesive film is 0.40 or more. (Process 1) Structure A is fabricated by attaching the side of the adhesive film opposite to the adhesive resin layer (C) of a 5cm x 5cm piece of adhesive film to a SUS substrate measuring 30cm x 30cm and 1.5mm thick. Next, the structure A is heated at 150°C for 1 hour using a forced-air constant-temperature incubator. Next, the structure A is placed on the hot plate with the SUS substrate side facing downwards, and the structure A is heated using the hot plate at 200°C for 60 seconds. (Method 1) The arithmetic mean roughness Ra1 of the adhesive resin layer (C) is measured using a surface roughness measuring instrument in accordance with JIS B 0601:2013. (Method 2) A 1000g weight having a 1cm × 1cm surface is placed on the adhesive resin layer (C) of the structure A such that the 1cm × 1cm surface of the weight is in contact with the 1cm × 1cm surface of the adhesive resin layer (C) including the center, and the structure is left standing at 200°C for 1 hour. Next, after removing the weight from the structure A, the structure A is cooled at 23°C for 5 minutes. Next, using a surface roughness measuring instrument, the arithmetic mean roughness Ra2 of the portion of the adhesive resin layer (C) that was in contact with the weight is measured in accordance with JIS B 0601:2013. [2] A method for manufacturing an electronic device according to [1], wherein the arithmetic mean roughness Ra1 is 5.0 μm or more. [3] A method for manufacturing an electronic device according to [1] or [2], wherein the arithmetic mean roughness Ra2 is 2.0 μm or more. [4] The method for manufacturing an electronic device according to any one of [1] to [3], wherein the thermally expandable microspheres contain a thermosetting resin. [5] The thermally expandable microspheres include a shell and a volatile blowing agent within the shell. The method for manufacturing an electronic device according to [4], wherein the shell contains the thermosetting resin. [6] The method for manufacturing an electronic device according to [4] or [5], wherein the curing temperature of the thermosetting resin is equal to or higher than the foaming temperature of the thermally expandable microspheres. [7] The method for manufacturing an electronic device according to any one of [1] to [6], wherein the foaming temperature of the thermally expandable microspheres is 160°C or higher. [8] The method for manufacturing an electronic device according to any one of [1] to [7], wherein the adhesive resin layer (C) is a layer whose adhesive strength decreases by heat treatment. [9] The method for manufacturing an electronic device according to any one of [1] to [8], wherein the adhesive resin layer (C) contains one or more selected from the group consisting of (meth)acrylic adhesive resins, silicone adhesive resins, urethane adhesive resins, olefin adhesive resins, and styrene adhesive resins.

[10] The method for manufacturing an electronic device according to any one of [1] to [9], wherein the content of the thermally expandable microspheres in the adhesive resin layer (C) is 5% to 50% when the total amount of the adhesive resin layer (C) is 100% by mass.

[11] In the volume-based cumulative frequency distribution curve of the thermally expandable microspheres measured by a laser diffraction / scattering particle size distribution analyzer, the particle diameter D at the time when the cumulative frequency is 50%. 50 The method for manufacturing an electronic device according to any one of [1] to

[10] , wherein the particle diameter D is 5 μm or more and 40 μm or less.

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

[11] , wherein the base material layer (A) contains one or more selected from the group consisting of polypropylene, polyethylene terephthalate, polyethylene naphthalate, polyamide, polyimide, and polyether ether ketone.

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

[12] , wherein the thickness of the adhesive resin layer (C) is 10 μm or more and 100 μm or less.

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

[13] , wherein the number of foreign matters observed in the adhesive film according to the following (method for observing foreign matters) is less than 10. (Method for observing foreign matters) Attach the adhesive resin layer (C) of the adhesive film to a silicon wafer to produce a structure 1. Next, heat the structure 1 under the conditions of 150 °C for 1 hour. Next, heat the structure 1 under the conditions of 200 °C for 60 seconds. Next, peel the adhesive film from the silicon wafer. Next, observe the number of foreign matters derived from the adhesive film present in a 1 cm × 1 cm area on the surface of the silicon wafer using a microscope under a magnification of 500 times. [1 (15)] Further comprising an adhesive resin layer (B) capable of temporarily fixing at least one of the electronic component and the substrate. The method for manufacturing an electronic device according to any one of [1] to

[14] , wherein the base material layer (A) is located between the adhesive resin layer (B) and the adhesive resin layer (C).

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

[15] , wherein the thickness of the adhesive resin layer (B) is 1 μm or more and 40 μm or less.

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

[15] or

[16] , further comprising an intermediate layer (D) in at least one of the space between the base material layer (A) and the adhesive resin layer (B) and the space between the base material layer (A) and the adhesive resin layer (C).

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

[17] , wherein the thickness of the intermediate layer (D) is 5 μm or more and 100 μm or less. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a method for manufacturing an electronic device that can reduce contamination of the target object. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic cross-sectional view showing an example of a method for manufacturing the electronic device of this embodiment. [Figure 2] This is a schematic cross-sectional view showing an example of a method for manufacturing the electronic device of this embodiment. [Figure 3] This is a schematic cross-sectional view showing an example of a method for manufacturing the electronic device of this embodiment. [Figure 4] This is a schematic cross-sectional view showing an example of the structure of the adhesive film used in the manufacturing method of the electronic device of this embodiment, together with the workpiece and support member. [Figure 5] This is a schematic cross-sectional view showing an example of the structure of the adhesive film used in the manufacturing method of the electronic device of this embodiment, together with the workpiece and support member. [Figure 6] This is a schematic cross-sectional view showing an example of the structure of the adhesive film used in the manufacturing method of the electronic device of this embodiment, together with the workpiece and support member. [Figure 7] This is a schematic cross-sectional view showing an example of the structure of the adhesive film used in the manufacturing method of the electronic device of this embodiment, together with the workpiece and support member. [Modes for carrying out the invention]

[0012] In this specification, the term "(meth)acrylate" refers to a concept that encompasses both acrylate and methacrylate. The same applies to similar terms such as "(meth)acryloyl." Each component described in this specification may be used individually or in combination of two or more. Furthermore, unless otherwise specified, the numerical range "A to B" indicates a range between A and B. To avoid complexity, if there are multiple identical components in the same drawing, a reference numeral may be assigned to only one of them, and not to all of them. The drawings are for illustrative purposes only. The shapes and dimensional ratios of the components shown in the drawings do not necessarily correspond to those of actual items.

[0013] Conventionally, adhesive films have sometimes used thermoplastic microspheres that expand easily. The inventors' research revealed that when heating to peel off an adhesive film, if the heating temperature is high or the heating time is long, the expanded thermoplastic microspheres become prone to tearing. Furthermore, when peeling off an adhesive film containing these easily torn thermoplastic microspheres, a portion of the adhesive film remains on the object to which it was temporarily fixed, resulting in contamination of the object. This also led to the discovery that the object could become contaminated during the manufacturing process of electronic devices. Further investigation by the inventors revealed that the surface roughness of the adhesive film, measured under predetermined conditions, is related to the contamination of the object by the adhesive film after heating. Further investigation by the inventors revealed that by setting the ratio of the arithmetic mean roughness, described later, to a predetermined value or higher, an adhesive film that can reduce contamination of the object can be obtained, thus completing the present invention.

[0014] <Method of manufacturing electronic devices> The method for manufacturing the electronic device of this embodiment includes a step of preparing a structure comprising an adhesive film having a base layer (A) and an adhesive resin layer (C), and a workpiece temporarily fixed to the adhesive resin layer (C). The method for manufacturing the electronic device of this embodiment also includes a step of processing the workpiece temporarily fixed to the adhesive resin layer (C). In the method for manufacturing the electronic device of this embodiment, the adhesive resin layer (C) includes thermally expandable microspheres. In the method for manufacturing the electronic device of this embodiment, the ratio (Ra2 / Ra1) of the arithmetic mean roughness Ra2 obtained by the following (Method 2) after the following (Process 1) to the arithmetic mean roughness Ra1 obtained by the following (Method 1) after the following (Process 1) of the adhesive film is 0.40 or more. (Process 1) Structure A is fabricated by attaching the side of a 5cm x 5cm adhesive film opposite to the adhesive resin layer (C) to a 30cm x 30cm, 1.5mm thick SUS substrate. Next, structure A is heated at 150°C for 1 hour using a forced-air constant-temperature incubator. Next, structure A is placed on the hot plate with the SUS substrate side facing down, and structure A is heated using the hot plate at 200°C for 60 seconds. (Method 1) The arithmetic mean roughness Ra1 of the adhesive resin layer (C) is measured using a surface roughness measuring instrument in accordance with JIS B 0601:2013. (Method 2) A 1000g weight with a 1cm x 1cm surface is placed on the adhesive resin layer (C) of structure A, such that the 1cm x 1cm surface of the weight is in contact with the 1cm x 1cm surface of the adhesive resin layer (C) including the center, and left to stand at 200°C for 1 hour. Next, after removing the weight from structure A, structure A is cooled at 23°C for 5 minutes. Next, using a surface roughness measuring instrument, the arithmetic mean roughness Ra2 of the portion of the adhesive resin layer (C) that was in contact with the weight is measured in accordance with JIS B 0601:2013. The manufacturing method of the electronic device of this embodiment, having the above-described configuration, can reduce contamination of the target object.

[0015] The reason for this is not entirely clear, but the following reasons can be inferred. The above ratio (Ra2 / Ra1) is thought to represent the degree of decrease in the arithmetic mean roughness of the surface of the adhesive resin layer (C) of the adhesive film used in the manufacturing method of the electronic device of this embodiment, before and after heat treatment. In other words, when the ratio (Ra2 / Ra1) is large (close to 1), it is thought to indicate that the arithmetic mean roughness of the surface of the adhesive resin layer (C) of the adhesive film does not decrease easily after heat treatment. Furthermore, since the adhesive film used in the manufacturing method of the electronic device of this embodiment has a ratio (Ra2 / Ra1) of 0.40 or higher, it is considered that the arithmetic mean roughness Ra of the adhesive resin layer (C) does not decrease easily after heat treatment. In other words, it is considered that the adhesive film used in the manufacturing method of the electronic device of this embodiment can maintain an arithmetic mean roughness Ra of the adhesive resin layer (C) after heat treatment at a certain level or higher compared to the arithmetic mean roughness Ra of the adhesive resin layer (C) before heat treatment. For this reason, it is considered that the adhesive film used in the manufacturing method of the electronic device of this embodiment makes it difficult for the object to adhere to the adhesive resin layer (C) even after heat treatment, thus reducing contamination of the object caused by the adhesive film.

[0016] The following describes a method for manufacturing an electronic device (manufacturing method X) when the adhesive resin layer (C) of the adhesive film 10 of this embodiment, which will be described later, is in contact with the workpiece 20.

[0017] [Manufacturing method X] Manufacturing method X includes, for example, the following two steps: (1) A step (step X1) to prepare a structure 100 including an adhesive film 10 and a workpiece 20 temporarily fixed to the adhesive film 10. (2) Process of processing the workpiece 20 that has been temporarily fixed to the adhesive film 10 (Process X2)

[0018] As described above, the adhesive film 10 of this embodiment can reduce contamination of the object. Therefore, according to the manufacturing method of an electronic device using the adhesive film 10 of this embodiment (manufacturing method X), contamination of the object to be processed 20 can be reduced. Consequently, according to the manufacturing method of an electronic device using the adhesive film 10 of this embodiment (manufacturing method X), contamination of the electronic device can be reduced.

[0019] The following describes each step of manufacturing method X, with reference to Figure 1.

[0020] (Process X1) In step X1, a structure 100 is prepared, which includes an adhesive film 10 and a workpiece 20 temporarily fixed to the adhesive resin layer (C) of the adhesive film 10. In other words, step X1 includes a step of preparing a structure 100 which includes an adhesive film 10 and a workpiece 20 temporarily fixed to the adhesive resin layer (C) of the adhesive film 10. If the adhesive film 10 further comprises an adhesive resin layer (B), the structure 100 is preferably temporarily fixed to the support member 30 by the adhesive resin layer (B) of the adhesive film 10. If the adhesive film 10 does not have an adhesive resin layer (B), the structure 100 may be temporarily fixed to the support member 30 by, for example, a fixing ring, a vacuum chuck, or the like. Furthermore, the temporary fixing of the adhesive resin layer (B) of the adhesive film 10 to the workpiece 20 and the temporary fixing of the adhesive resin layer (C) of the adhesive film 10 to the support member 30 may be performed simultaneously, or one temporary fixing may be performed after the other temporary fixing.

[0021] Such a structure 100 can be fabricated, for example, by following the procedure below. First, the adhesive film 10 is placed on the support member 30 so that the first surface A1 of the base material layer (A) faces the support member 30. Next, the adhesive film 10 is temporarily fixed to the support member 30 using a fixing ring, vacuum chuck, etc. Note that in Figure 1, the components for temporarily fixing the adhesive film 10 to the support member 30 are not shown. Furthermore, if the adhesive film 10 further comprises an adhesive resin layer (B) on the first surface A1 side of the base layer (A), it can be manufactured, for example, by the following procedure. The adhesive film 10 is attached to the support member 30 so that the adhesive resin layer (B) faces the support member 30. A protective film called a separator may be attached to the adhesive resin layer (B). In this case, the protective film is peeled off and the exposed surface of the adhesive resin layer (B) is attached to the surface of the support member 30.

[0022] Next, the structure 100 can be manufactured by attaching the workpiece 20 to the adhesive resin layer (C) of the adhesive film 10 located on the support member 30.

[0023] The adhesive film 10 may be placed on the support member 30 by hand, but it can also usually be done using an automatic adhesive machine or the like equipped with a roll of adhesive film 10. Furthermore, the object to be processed 20 may be attached to the adhesive film 10 by hand or by using a device. There are no particular restrictions on the temperature of the adhesive film 10 and the workpiece 20 when applied, but a temperature of 25°C to 80°C is preferred. Furthermore, there are no particular restrictions on the pressure applied to the adhesive film 10 and the workpiece 20 during application, but a pressure of 0.3 MPa or more and 0.5 MPa or less is preferred.

[0024] (Process X2) In process X2, the workpiece 20, which is temporarily fixed to the adhesive film 10, is processed. The content of the processing applied to the workpiece 20 is not particularly limited. In Figure 1, the workpiece 20 is the workpiece 40 after processing. The processing applied to the workpiece 20 may, for example, be the sealing of electronic components with a sealing material. Alternatively, the processing applied to the workpiece 20 may, for example, be the dicing of a ceramic capacitor using a dicing device. Alternatively, the processing applied to the workpiece 20 may, for example, be the dicing of electronic components using a dicing device. Alternatively, the processing applied to the workpiece 20 may, for example, be the processing of a thin glass substrate, such as the formation of electronic components on a thin glass substrate.

[0025] (Process X3) The manufacturing method X preferably further includes step X3 after step X2. In step X3, external stimuli are applied to reduce the adhesive strength of the adhesive resin layer (C), thereby peeling the processed workpiece 40 from the structure 100.

[0026] For example, after processing the workpiece 20, the structure 100 can be heated to a temperature of 160°C or higher to reduce the adhesive strength of the adhesive resin layer (C), thereby separating the processed workpiece 40 from the structure 100. Specifically, by heating the structure 100, the thermally expandable microspheres in the adhesive resin layer (C) of the adhesive film 10 are foamed, thereby reducing the adhesive strength. The method for heating the structure 100 is not particularly limited, but examples include electric heaters, dielectric heating, magnetic heating, heating by electromagnetic waves (near-infrared, mid-infrared, far-infrared, etc.), ovens, hot plates, and other heat treatment methods.

[0027] The heating temperature should be above the foaming temperature of the thermally expandable microspheres, for example, it may be between 160°C and 250°C, between 170°C and 240°C, or between 180°C and 230°C.

[0028] Furthermore, manufacturing method X may include additional steps other than steps X1 to X3, if necessary.

[0029] Next, we will explain manufacturing method X using specific examples (manufacturing method Xa and manufacturing method Xb).

[0030] [Manufacturing method Xa] First, we will explain the manufacturing method X (hereinafter also referred to as manufacturing method Xa) when the processing applied to the workpiece 20 is dicing of an electronic component 21. Manufacturing method Xa includes, for example, the following two steps: (1) A step (step X1a) to prepare a structure 200 including an adhesive film 10 and an electronic component 21 temporarily fixed to the adhesive film 10. (2) Dicing process for electronic component 21 (process X2a)

[0031] The following describes each step of manufacturing method Xa with reference to Figure 2. The adhesive film 10 used in manufacturing method Xa further comprises an intermediate layer (D) located between the base layer (A) and the adhesive resin layer (C).

[0032] (Process X1a) In step X1a, a structure 200 is prepared, comprising an adhesive film 10 and an electronic component 21 temporarily fixed to an adhesive resin layer (C). The structure 200 can be manufactured, for example, by attaching electronic components 21 to the adhesive resin layer (C) of the adhesive film 10. Note that process X1a corresponds to process X1 of manufacturing method X.

[0033] (Process X2a) In step X2a, the electronic components 21 temporarily fixed to the adhesive film 10 are diced to obtain multiple electronic components 41. In this specification, "dicing" refers to the operation of dividing an electronic component 21 to obtain multiple divided electronic components 41. In the dicing process described above, for example, a dicing blade with a tapered cross-sectional shape at the tip of its outer circumference can be used. Furthermore, the electronic component 41 in process X2a includes multiple divided electronic components 41 obtained by dicing. Note that process X2a corresponds to process X2 of manufacturing method X.

[0034] (Process X3a) The manufacturing method Xa preferably further includes step X3a after step X2a. In step X3a, the adhesive film 10 is subjected to external stimulation before the pickup step (step X4a) to reduce the adhesive force of the adhesive resin layer (C) to the electronic component 41. By performing step X3a, the electronic component 41 can be easily picked up from the adhesive resin layer (C). In addition, contamination of the surface of the electronic component 41 by the adhesive components constituting the adhesive resin layer (C) can be reduced. External stimuli applied to the adhesive film 10 include, for example, heating the adhesive film 10. Heating the adhesive film 10 can be performed, for example, by placing the structure 200 in a constant temperature bath or oven, or by heating it with a heater provided on a sample stage that holds the support substrate 31. Note that process X3a corresponds to process X3 of manufacturing method X.

[0035] (Process X4a) The manufacturing method Xa may preferably include step X4a after step X3a. In step X4a, the diced electronic components 41 are picked up from the adhesive film 10. This pickup allows the electronic component 41 to be peeled off the adhesive film 10. Known methods can be used to pick up the electronic component 41.

[0036] (Other processes) Manufacturing method Xa may include other steps not described above. These other steps may include processes known in the manufacturing of electronic devices.

[0037] For example, after performing step X4a, any additional steps commonly performed in the manufacturing process of electronic devices may be carried out, such as mounting the obtained electronic component 41 onto a circuit board, wire bonding, sealing, or solder reflow.

[0038] [Manufacturing method Xb] Next, we will explain the manufacturing method X (hereinafter also referred to as manufacturing method Xb) when the processing applied to the workpiece 20 is the processing of a thin glass substrate 22.

[0039] Processing methods for the thin glass substrate 22 include cutting the thin glass substrate 22, forming organic EL elements on the thin glass substrate 22, inkjet processing, gravure printing, screen printing, spray coating, dispenser coating, air spray, electrostatic coating, roll coating, brush coating, roller brush coating, and dipping coating. Applications of the processed thin glass substrate 22 include, for example, cover glass for smartphones; flexible displays such as organic EL elements; water vapor and oxygen barrier layers for organic EL elements, etc.; flexible lighting, cover glass for various sensors, etc.

[0040] In the following section, the manufacturing method Xb will be explained using the formation of an organic EL element (electronic component 23) on a thin glass substrate 22 as an example, with reference to Figure 3.

[0041] Manufacturing method Xb includes, for example, the following two steps: (1) A step (step X1b) to prepare a structure 300 including an adhesive film 10 and a thin glass substrate 22 attached to the adhesive film 10. (2) Step of forming electronic components 23 on a thin glass substrate 22 (Step X2b)

[0042] The following describes each step of manufacturing method Xb with reference to Figure 3. The adhesive film 10 used in manufacturing method Xb further comprises an adhesive resin layer (B) and an intermediate layer (D) located between the base layer (A) and the adhesive resin layer (C).

[0043] (Process X1b) In step X1b, a structure 300 is prepared, comprising an adhesive film 10 and a thin glass substrate 22 temporarily fixed to an adhesive resin layer (C). Preferably, the structure 300 further includes a support substrate 31 attached to the adhesive resin layer (B) of the adhesive film 10. Note that process X1b corresponds to process X1 of manufacturing method X.

[0044] Such a structure 300 can be fabricated, for example, by following the procedure below. First, the adhesive film 10 is attached to the support substrate 31 so that the adhesive resin layer (B) faces the support substrate 31.

[0045] Next, the structure 300 can be fabricated by attaching the thin glass substrate 22 onto the adhesive resin layer (C) of the adhesive film 10 attached to the support substrate 31. The material constituting the support substrate 31 used in manufacturing method Xb is not particularly limited as long as the thin glass substrate 22 can be held by the adhesive film 10, but it is preferably a material harder than the thin glass substrate 22. Examples of materials for the support substrate 31 used in manufacturing method Xb include silicon, glass, SUS plate, copper plate, acrylic plate, etc. The thickness of the support substrate 31 used in manufacturing method Xb is, for example, 0.4 mm or more and 5.0 mm or less. Furthermore, the thickness of the thin glass substrate 22 is preferably 10 μm to 150 μm, more preferably 15 μm to 70 μm, and even more preferably 20 μm to 50 μm, from the viewpoint of improving the balance between flexibility and ease of processing.

[0046] (Process X2b) In step X2b, an electronic component 23 is formed on a thin glass substrate 22 that is temporarily fixed to the adhesive resin layer (C) of the adhesive film 10. The electronic component 23 is, for example, an organic EL element. Organic EL elements are composed of, for example, an anode, a hole injection layer, a hole transport layer, a light-emitting layer, a hole blocking layer, an electron transport layer, and a cathode. For the formation of organic EL elements, for example, a thin film made of an anode material (e.g., indium tin oxide: ITO, etc.) is formed to a thickness of 10 to 200 nm using a vacuum deposition method such as PVD (physical deposition) or CVD (chemical deposition) to create the anode. The conditions for the vacuum deposition method are, for example, a deposition temperature of 70 to 250°C and a vacuum level of 10°C. ―2 ~10 ―6 Pa, deposition rate is 0.01 to 30 nm / second.

[0047] Next, organic compound thin films consisting of a hole injection layer, a hole transport layer, a light-emitting layer, a hole blocking layer, and an electron transport layer, which are organic EL element materials, are formed on top of this. Methods for forming organic compound thin films include, for example, dry processes (such as vacuum deposition) and wet processes (such as spin coating, casting, inkjet, and printing). From the viewpoint of uniformity and low defect rate of the organic compound thin film, the preferred method for forming the organic compound thin film is one or more selected from the group consisting of vacuum deposition, spin coating, inkjet, and printing.

[0048] After forming an organic compound thin film, a thin film made of cathode material is formed on top of it by vacuum deposition to a thickness of 50 to 200 nm to create the cathode. As a result, an organic EL element (electronic component 23) can be formed on the thin glass substrate 22. Furthermore, an electronic component 42 (the thin glass substrate 22 on which the electronic component 23 is formed) can be manufactured. Note that process X2b corresponds to process X2 of manufacturing method X.

[0049] (Process X3b) The manufacturing method Xb may preferably include step X3b after step X2b. In step X3b, the electronic component 42 is peeled off the adhesive film 10. In step X3b, the adhesive force of the adhesive resin layer (C) is reduced by applying an external stimulus to peel the electronic component 42 off the structure 300. Specifically, the adhesive force is reduced by heating the structure 300 to cause the thermally expandable microspheres in the adhesive resin layer (C) of the adhesive film 10 to foam. Note that process X3b corresponds to process X3 of manufacturing method X.

[0050] <Applications of manufacturing methods for electronic devices> The method for manufacturing an electronic device according to this embodiment can reduce contamination of the object, and therefore its applications are not particularly limited; it can be used in the manufacturing of an electronic device that includes a step of temporarily fixing various objects. Here, in this specification, "object" means an object that is temporarily fixed by an adhesive film. The object includes, for example, one or more selected from the group consisting of a workpiece and a support member. Herein, "workpiece" means an object that is processed while being temporarily fixed to another object by an adhesive film. Also, in this specification, "support member" means a member that temporarily fixes the workpiece with an adhesive film. The workpiece includes, for example, one or more types selected from the group consisting of electronic components and circuit boards.

[0051] Examples of electronic components include semiconductor chips, semiconductor panels, semiconductor packages, electrical elements, display devices, thermal heads, and solar cells. Examples of semiconductor chips include ICs, LSIs, discrete components, light-emitting diodes, and photodetectors. Examples of electrical elements include ceramic capacitors and oscillators. Examples of semiconductor packages include fan-out type packages.

[0052] Examples of substrates include semiconductor substrates, package substrates in which multiple semiconductor chips are encapsulated together with sealing resin, printed circuit boards (multilayer ceramic sheets), green sheets for multilayer ceramic capacitors, and thin glass substrates. Examples of semiconductor substrates include silicon substrates, germanium substrates, gallium-arsenide substrates, gallium-phosphorus substrates, and gallium-arsenide-aluminum substrates. Preferably, the semiconductor substrate includes a semiconductor substrate on which circuits are formed on the surface. Examples of package substrates in which multiple semiconductor chips are encapsulated together with a sealing resin include mold array package substrates, fan-out type package substrates, and wafer-level package substrates. Examples of thin glass substrates include glass substrates having a thickness of 10 μm to 150 μm.

[0053] The support member is not particularly limited as long as it can hold the workpiece with an adhesive film. Examples of support members include support substrates and support bases. Examples of support substrates include silicon substrates, glass substrates, SUS substrates, copper substrates, and acrylic substrates.

[0054] The adhesive film of this embodiment can temporarily fix at least one of the electronic components and the substrate. Furthermore, the adhesive film of this embodiment can be applied to one or more types selected from the group consisting of, for example, tapes for temporarily fixing electronic components, tapes for processing substrates, dicing tapes, backgrinding tapes, and surface protection tapes.

[0055] The adhesive film of this embodiment can be used as a temporary fixing tape for electronic components, for example, to manufacture electronic devices including fan-out type packages. In other words, in this case, the electronic device of this embodiment includes a semiconductor package, for example, a fan-out type package. Furthermore, the adhesive film of this embodiment may be used as a temporary fixing tape for electronic components to temporarily fix other types of electronic components.

[0056] Furthermore, the adhesive film of this embodiment can be used as a dicing tape, for example, to temporarily fix electronic components in the dicing process of electronic components. Examples of electronic component dicing processes include the dicing process of semiconductor packages; the dicing process of electrical elements such as ceramic capacitors; and the dicing process of other electronic components such as semiconductor chips, semiconductor panels, display devices, thermal heads, and solar cells.

[0057] Furthermore, the adhesive film of this embodiment can be used as a backgrind tape, for example, to temporarily fix electronic components in the backgrinding process of electronic components.

[0058] Furthermore, the adhesive film of this embodiment can be used as a substrate processing tape, for example, to temporarily fix a thin glass substrate in the processing of a thin glass substrate. Furthermore, the substrate processing tape may be used not only for thin glass substrates but also for processing other types of substrates.

[0059] Furthermore, the adhesive film of this embodiment can be used as a surface protection tape, for example, to protect the surface of an object.

[0060] <Composition of the adhesive film> Next, the thermally expandable microspheres and each layer that constitute the adhesive film used in the manufacturing method of the electronic device of this embodiment will be described.

[0061] [Thermally expandable microspheres] Thermally expandable microspheres are, for example, tiny spherical resin compositions that expand when heated. The thermally expandable microspheres of this embodiment include, for example, a thermoplastic resin, a volatile expanding agent, a thermosetting resin, a curing agent, and other additives. From the viewpoint of further reducing contamination of the target object, the thermally expandable microspheres of this embodiment preferably include a thermosetting resin.

[0062] The thermally expandable microspheres preferably comprise a shell and a volatile expanding agent within the shell. In this case, the shell more preferably comprises a thermosetting resin. The thermally expandable microspheres more preferably have a structure that encapsulates a volatile expanding agent within the space inside the shell. With such a structure, for example, when heated, the volatile expanding agent volatilizes and turns into a gas, causing the shell to expand.

[0063] The thermosetting resin includes, for example, one or more selected from the group consisting of epoxy resins, phenolic resins, melamine resins, urea resins, polyimide resins, and bismaleimide resins. From the viewpoint of further reducing contamination of the object, the thermosetting resin preferably includes one or more selected from the group consisting of epoxy resins and phenolic resins. The epoxy resin includes, for example, one or more types selected from the group consisting of bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, dicyclopentadiene type epoxy resin, and glycidylamine type epoxy resin. The phenolic resin includes, for example, one or more types selected from the group consisting of novolac-type phenolic resins, resol-type phenolic resins, and benzylic ether-type phenolic resins.

[0064] When the thermally expandable microspheres contain a thermosetting resin, the thermally expandable microspheres preferably contain a curing agent from the viewpoint of being able to cure the thermosetting resin. The curing agent can be selected according to the type of thermosetting resin. The thermally expandable microspheres may contain a catalyst used to cure the thermosetting resin as needed.

[0065] The shell may include a thermoplastic resin in addition to a thermosetting resin as a material for forming the shell. The thermoplastic resin used as a material for forming the shell may include, for example, one or more selected from the group consisting of vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, and polysulfone.

[0066] A volatile expanding agent is, for example, a substance that turns into a gas when heated. A volatile expanding agent includes, for example, one or more substances selected from the group consisting of ethane, ethylene, propane, propene, n-butane, isobutane, butene, isobutene, n-pentane, isopentane, neopentane, n-hexane, heptane, and petroleum ether. From the viewpoint of improving the foaming rate of the thermally expandable microspheres, the volatile expansion agent preferably includes one or more selected from the group consisting of propane, n-butane, isobutane, n-pentane, isopentane, and neopentane.

[0067] Thermally expandable microspheres can be manufactured, for example, by coacervation, interfacial polymerization, or the like.

[0068] The curing temperature of the thermosetting resin is preferably above the foaming temperature of the thermally expandable microspheres, from the viewpoint of reducing damage to the thermally expandable microspheres due to heating. The curing temperature of the thermosetting resin is the temperature at which the thermosetting resin begins to harden due to crosslinking reactions, etc. The foaming temperature of the thermally expandable microspheres is the temperature at which the volume of the thermally expandable microspheres begins to increase due to the vaporization of the volatile expanding agent.

[0069] The foaming temperature of the thermally expandable microspheres is preferably 160°C or higher, more preferably 165°C or higher, even more preferably 170°C or higher, even more preferably 175°C or higher, and even more preferably 180°C or higher, from the viewpoint of facilitating the formation of the adhesive resin layer (C) containing the thermally expandable microspheres. The upper limit of the foaming temperature of the thermally expandable microspheres is not particularly limited, but may be, for example, 300°C or less, 275°C or less, 250°C or less, 225°C or less, or 200°C or less. The foaming temperature of the thermally expandable microspheres is preferably 160°C to 300°C, more preferably 165°C to 275°C, even more preferably 170°C to 250°C, even more preferably 175°C to 225°C, and even more preferably 180°C to 200°C, from the viewpoint of facilitating the formation of the adhesive resin layer (C) containing the thermally expandable microspheres.

[0070] In the volume-based cumulative frequency distribution curve of thermally expandable microspheres, measured by a laser diffraction scattering particle size distribution analyzer, the particle size D at 50% cumulative frequency is... 50 From the viewpoint of improving the peelability of the adhesive film, the thickness is preferably 5 μm to 40 μm, more preferably 10 μm to 30 μm, and even more preferably 15 μm to 25 μm.

[0071] [Base material layer (A)] The base layer (A) is a layer provided for the purpose of improving the handling properties, mechanical properties, heat resistance, and other characteristics of the adhesive film. The base layer (A) is not particularly limited, but an example is a resin film. The base layer (A) has a first surface A1 and a second surface A2 which is the surface opposite to the first surface A1.

[0072] The resin constituting the resin film includes, for example, thermoplastic resins. The resin constituting the resin film includes, for example, one or more selected from the group consisting of polyolefins, polyesters, polyamides, poly(meth)acrylates, polyvinyl chlorides, polyvinylidene chlorides, polyimides, polyetherimides, ethylene-vinyl acetate copolymers, polyacrylonitriles, polycarbonates, polystyrenes, ionomers, polysulfones, polyethersulfones, polyphenylene ethers, and aromatic polyetherketones. Polyolefins include, for example, one or more selected from the group consisting of polyethylene, polypropylene, poly(4-methyl-1-pentene), and poly(1-butene). Polyester includes, for example, one or more selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. The polyamide includes, for example, one or more selected from the group consisting of nylon-6, nylon-66, and polymetaxylene adipamide. Aromatic polyetherketones include, for example, one or more selected from the group consisting of polyetherketone (PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetheretherketoneketone (PEEKK), and polyetherketone esters.

[0073] The resin constituting the resin film preferably comprises one or more selected from the group consisting of polypropylene, polyethylene terephthalate, polyethylene naphthalate, polyamide, polyimide, and polyetheretherketone, from the viewpoint of improving the balance of transparency, mechanical strength, and price, more preferably comprising one or more selected from the group consisting of polyethylene terephthalate and polyethylene naphthalate, and even more preferably comprising polyethylene terephthalate.

[0074] The base layer (A) may be a single layer or two or more layers. Furthermore, the resin film for forming the base layer (A) is, for example, a stretched film, and from the viewpoint of improving the mechanical strength of the base layer (A), it is preferably a film stretched in one or two axes.

[0075] From the viewpoint of improving film properties, the thickness of the substrate layer (A) is preferably 1 μm to 500 μm, more preferably 5 μm to 400 μm, even more preferably 10 μm to 300 μm, even more preferably 20 μm to 200 μm, even more preferably 25 μm to 100 μm, even more preferably 30 μm to 50 μm, and even more preferably 35 μm to 45 μm.

[0076] [Adhesive resin layer (B)] The adhesive film of this embodiment may further comprise an adhesive resin layer (B). The adhesive resin layer (B) is located on one side (the first surface A1 side) of the substrate layer (A). The adhesive resin layer (B) is, for example, a layer for temporarily fixing an object by contacting its surface. The adhesive resin layer (B) can, for example, temporarily fix at least one of the workpiece and the support member.

[0077] The adhesive resin (B1) constituting the adhesive resin layer (B) preferably includes one or more selected from the group consisting of (meth)acrylic adhesive resins, silicone adhesive resins, urethane adhesive resins, olefin adhesive resins, and styrene adhesive resins, from the viewpoint of improving the balance between adhesive strength and heat resistance. The adhesive resin (B1) constituting the adhesive resin layer (B) more preferably includes a (meth)acrylic adhesive resin, from the viewpoint of easily adjusting the adhesive strength.

[0078] As the adhesive resin layer (B), for example, a radiation-crosslinked adhesive resin layer whose adhesive strength can be reduced by radiation can be used. Since the radiation-crosslinked adhesive resin layer (B) crosslinks upon irradiation with radiation, reducing its adhesive strength, the adhesive film becomes easier to peel from the object. Examples of radiation include ultraviolet rays, electron beams, and infrared rays. As the radiation-crosslinked adhesive resin layer, an ultraviolet-crosslinked adhesive resin layer is preferred.

[0079] The adhesive resin layer (B) 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) is used to react with the functional groups of the adhesive resin (B1) to adjust the adhesive strength and cohesive strength of the adhesive resin layer (B).

[0080] The crosslinking agent (B2) comprises, for example, one or more selected from the group consisting of epoxy crosslinking agents, isocyanate crosslinking agents, aziridine crosslinking agents, tetrafunctional epoxy crosslinking agents, and melamine crosslinking agents, and preferably comprises one or more selected from the group consisting of epoxy crosslinking agents, isocyanate crosslinking agents, and aziridine crosslinking agents.

[0081] From the viewpoint of improving the balance between the adhesive strength and heat resistance performance of the adhesive resin layer (B), the content of the crosslinking agent (B2) in the adhesive resin layer (B) is preferably 0.1 parts by mass or more and 15 parts by mass or less, more preferably 1 part by mass or more and 12 parts by mass or less, even more preferably 3 parts by mass or more and 10 parts by mass or less, and even more preferably 5 parts by mass or more and 8 parts by mass or less, when the content of the adhesive resin (B1) in the adhesive resin layer (B) is 100 parts by mass.

[0082] From the viewpoint of improving the balance between adhesive strength and heat resistance, the total content of the adhesive resin (B1) and crosslinking agent (B2) in the adhesive resin layer (B) is preferably 50% to 100% by mass, more preferably 70% to 100% by mass, even more preferably 90% to 100% by mass, and even more preferably 95% to 100% by mass, when the total amount of the adhesive resin layer (B) is considered as 100% by mass.

[0083] In the adhesive film of this embodiment, when the adhesive strength of the adhesive resin layer (C) is reduced by heat treatment and the support member is peeled off from the adhesive resin layer (C), the amount of thermally expandable microspheres in the adhesive resin layer (B) is preferably 0.1% by mass or less, more preferably 0.05% by mass or less, even more preferably 0.01% by mass or less, and even more preferably 0% by mass, when the total amount of the adhesive resin layer (B) is 100% by mass.

[0084] The thickness of the adhesive resin layer (B) is preferably 1 μm to 40 μm, more preferably 2 μm to 30 μm, even more preferably 3 μm to 25 μm, even more preferably 4 μm to 20 μm, and even more preferably 5 μm to 15 μm, from the viewpoint of improving the balance between adhesive strength and heat resistance.

[0085] The adhesive resin layer (B) can be formed, for example, by applying an adhesive onto the substrate layer (A). The adhesive may be dissolved in a solvent and applied as a coating solution, applied as an aqueous emulsion, or applied directly as a liquid adhesive. Furthermore, the base material layer (A) and the adhesive resin layer (B) may be formed by co-extrusion molding, or they may be formed by laminating (layering) a film-like base material layer (A) and a film-like adhesive resin layer (B).

[0086] [Adhesive resin layer (C)] The adhesive resin layer (C) is a layer located on the second surface A2 side of the base layer (A). The adhesive resin layer (C) is preferably a layer whose adhesive strength decreases with heat treatment. This allows the adhesive film to be peeled off the object by heat treatment.

[0087] The adhesive resin layer (C) of this embodiment includes thermally expandable microspheres, from the viewpoint of improving thermal release properties.

[0088] In the adhesive resin layer (C) of this embodiment, the temperature at which the adhesive strength decreases or is lost is preferably 160°C or higher, more preferably 165°C or higher, even more preferably 170°C or higher, even more preferably 175°C or higher, and even more preferably 180°C or higher. Such an adhesive resin layer (C) can be formed by selecting the type of thermally expandable microspheres in the adhesive resin layer (C).

[0089] Here, the decrease or loss of adhesive strength due to heating at temperatures above 160°C can be evaluated, for example, by the following (Method for Evaluating Decrease in Adhesion Strength). In this specification, loss of adhesive strength means, for example, when the 180° peel strength measured under conditions of 23°C and a tensile speed of 300 mm / min falls below 0.5 N / 25 mm. (Method for evaluating the decrease in adhesive strength) The adhesive resin layer (C) side of the adhesive film is attached to a stainless steel plate and heat-treated at 140°C for 1 hour. Then, it is heated at a temperature of 160°C or higher for 2 minutes. After heating, the peel strength of the adhesive film from the stainless steel plate is measured. The specific heating temperature when heating to a temperature of 160°C or higher is set appropriately depending on the type of gas generated, the type of thermally expandable microspheres, the temperature at which the gas is generated, and the temperature at which the thermally expandable microspheres expand (foaming temperature).

[0090] From the viewpoint of improving thermal release properties, the content of thermally expandable microspheres in the adhesive resin layer (C) is preferably 5% to 50% by mass, more preferably 6% to 45% by mass, even more preferably 7% to 40% by mass, even more preferably 8% to 35% by mass, even more preferably 9% to 30% by mass, and even more preferably 10% to 25% by mass, when the total amount of the adhesive resin layer (C) is 100% by mass.

[0091] From the viewpoint of improving thermal release properties, the content of thermally expandable microspheres in the adhesive resin layer (C) is preferably 1 to 150 parts by mass, more preferably 3 to 100 parts by mass, even more preferably 5 to 50 parts by mass, even more preferably 8 to 40 parts by mass, even more preferably 10 to 30 parts by mass, and even more preferably 12 to 28 parts by mass, when the content of adhesive resin (C1) in the adhesive resin layer (C) is 100 parts by mass.

[0092] The adhesive resin (C1) constituting the adhesive resin layer (C) includes, for example, one or more types selected from the group consisting of (meth)acrylic adhesive resins, silicone adhesive resins, urethane adhesive resins, olefin adhesive resins, polyester adhesive resins, polyamide adhesive resins, fluorine adhesive resins, and styrene adhesive resins.

[0093] The adhesive resin (C1) constituting the adhesive resin layer (C) preferably includes 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, from the viewpoint of improving thermal release properties. The adhesive resin (C1) constituting the adhesive resin layer (C) more preferably includes a (meth)acrylic adhesive resin, from the viewpoint of easily adjusting the adhesive strength.

[0094] Examples of the (meth)acrylic adhesive resin (c) used in the adhesive resin layer (C) include copolymers comprising a constituent unit (c1) of an alkyl (meth)acrylate and a constituent unit (c2) having a functional group that can react with a crosslinking agent (C2).

[0095] (Meth)acrylic adhesive resin (c) can be produced, for example, by copolymerizing a monomer that forms a constituent unit (c1) of an alkyl (meth)acrylate (hereinafter also referred to as monomer (c1)) and a monomer that forms a constituent unit (c2) having a functional group that can react with a crosslinking agent (C2) (hereinafter also referred to as monomer (c2)).

[0096] The monomer (c1) preferably comprises one or more selected from the group consisting of alkyl (meth)acrylates having an alkyl group having about 1 to 12 carbon atoms, more preferably alkyl (meth)acrylates having an alkyl group having 1 to 8 carbon atoms, and even more preferably methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate.

[0097] The content of constituent unit (c1) in the (meth)acrylic adhesive resin (c) is preferably 10% by mass or more and 99% by mass or less, more preferably 50% by mass or more and 97% by mass or less, and even more preferably 85% by mass or more and 95% by mass or less, when the total amount of the (meth)acrylic adhesive resin (c) is 100% by mass.

[0098] The monomer (c2) includes, for example, one or more selected from the group consisting of (meth)acrylic acid, itaconic acid, mesaconic acid, citraconic acid, fumaric acid, maleic acid, monoalkyl itaconic acid, monoalkyl mesaconic acid, monoalkyl citraconic acid, monoalkyl fumaric acid, monoalkyl maleic acid, glycidyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, (meth)acrylamide, and t-butylaminoethyl (meth)acrylate. The monomer (c2) preferably comprises one or more selected from the group consisting of (meth)acrylic acid, (meth)acrylic acid-2-hydroxyethyl, and (meth)acrylamide.

[0099] The content of constituent units (c2) in the (meth)acrylic adhesive resin (c) is preferably 1% by mass or more and 40% by mass or less, more preferably 3% by mass or more and 20% by mass or less, and even more preferably 5% by mass or more and 15% by mass or less, when the total amount of the (meth)acrylic adhesive resin (c) is 100% by mass.

[0100] Polymerization reaction mechanisms for (meth)acrylic adhesive resin (c) include radical polymerization, anionic polymerization, and cationic polymerization. From the viewpoint of the manufacturing cost of (meth)acrylic adhesive resin (c), the influence of the functional groups of the monomer, and the influence of ions on the surface of the target object, radical polymerization is preferred as the polymerization reaction mechanism for (meth)acrylic adhesive resin (c).

[0101] The radical polymerization initiator includes, for example, one or more selected from the group consisting of organic peroxides, inorganic peroxides, and azo compounds. Organic peroxides include, for example, one or more selected from the group consisting of benzoyl peroxide, di-t-butyl peroxide, dicumyl peroxide, 3,3,5-trimethylhexanoyl peroxide, di-2-ethylhexyl peroxydicarbonate, methyl ethyl ketone peroxide, t-butyl peroxyphthalate, t-butyl peroxybenzoate, di-t-butyl peroxyacetate, t-butyl peroxyisobutyrate, t-butyl peroxy-2-hexanoate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxy-3,5,5-trimethylhexanoate, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, t-butyl peroxide, and di-t-amyl peroxide. The inorganic peroxide includes, for example, one or more selected from the group consisting of ammonium persulfate, potassium persulfate, and sodium persulfate. The azo compound includes, for example, one or more selected from the group consisting of 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, and 4,4'-azobis-4-cyanovaleric acid.

[0102] The radical polymerization initiator in the (meth)acrylic adhesive resin (c) preferably includes an organic peroxide, more preferably t-butyl peroxy-2-ethylhexanoate, from the viewpoint of improving the balance between the adhesive strength and heat resistance performance of the adhesive resin layer (C).

[0103] The adhesive resin layer (C) further comprises, in addition to the adhesive resin (C1), a crosslinking agent (C2) which preferably has two or more crosslinkable functional groups in one molecule. The crosslinking agent (C2) is used to react with the functional groups of the adhesive resin (C1) to adjust the tackiness and cohesiveness of the adhesive resin layer (C).

[0104] The crosslinking agent (C2) includes, for example, one or more selected from the group consisting of epoxy crosslinking agents, isocyanate crosslinking agents, aziridine crosslinking agents, tetrafunctional epoxy crosslinking agents, and melamine crosslinking agents. The epoxy crosslinking agent includes, for example, one or more selected from the group consisting of sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, neopentyl glycol diglycidyl ether, and resolcin diglycidyl ether. The isocyanate crosslinking agent includes, for example, one or more selected from the group consisting of tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate 3 adduct of trimethylolpropane, polyisocyanate, diphenylmethane diisocyanate, and tolylene diisocyanate. The aziridine crosslinking agent includes, for example, one or more selected from the group consisting of trimethylolpropane-tri-β-aziridinylpropionate, tetramethylolmethane-tri-β-aziridinylpropionate, N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide), N,N'-hexamethylene-1,6-bis(1-aziridinecarboxamide), N,N'-toluene-2,4-bis(1-aziridinecarboxamide), and trimethylolpropane-tri-β-(2-methylaziridine)propionate. The tetrafunctional epoxy crosslinking agent includes, for example, one or more selected from the group consisting of N,N,N',N'-tetraglycidyl-m-xylenediamine and 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane. Melamine-based crosslinking agents include, for example, hexamethoxymethylolmelamine.

[0105] In the adhesive resin layer (C), the crosslinking agent (C2) preferably includes one or more selected from the group consisting of epoxy crosslinking agents, isocyanate crosslinking agents, and aziridine crosslinking agents, from the viewpoint of improving the balance between adhesive strength and thermal release properties.

[0106] The amount of crosslinking agent (C2) in the adhesive resin layer (C) is preferably within a range where the number of functional groups in the crosslinking agent (C2) does not exceed the number of functional groups in the adhesive resin (C1). However, if new functional groups are generated in the crosslinking reaction, or if the crosslinking reaction is slow, etc., an excess amount may be included as needed. From the viewpoint of improving the balance between adhesive strength and thermal release properties, the lower limit of the crosslinking agent (C2) content in the adhesive resin layer (C) is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 2 parts by mass or more, when the content of the adhesive resin (C1) in the adhesive resin layer (C) is 100 parts by mass. Furthermore, from the viewpoint of improving storage stability, the upper limit of the crosslinking agent (C2) content in the adhesive resin layer (C) is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 4 parts by mass or less, when the content of the adhesive resin (C1) in the adhesive resin layer (C) is 100 parts by mass.

[0107] The adhesive resin layer (C) preferably further contains a tackifying resin (C3) from the viewpoint of improving adhesive strength. Including the tackifying resin (C3) in the adhesive resin layer (C) makes it easier to adjust the adhesion to the object at or near room temperature.

[0108] The tackifying resin (C3) includes, for example, one or more selected from the group consisting of rosin resins, terpene resins, natural rosin resins, petroleum resins, and coumarone-indene resins. Rosin-based resins include, for example, rosin-based derivatives that have undergone treatment such as esterification. The terpene resin includes, for example, one or more selected from the group consisting of α-pinene resins, β-pinene resins, dipentene resins, and terpene phenol resins. Natural rosin resins include one or more selected from the group consisting of gum resins, wood resins, and tall oil resins. Petroleum resins include, for example, resins obtained by hydrogenating, disproportionating, polymerizing, or maleating natural rosin resins.

[0109] In the adhesive resin layer (C) of this embodiment, the softening point of the tackifying resin (C3) is preferably 100°C to 160°C, more preferably 120°C to 150°C, from the viewpoint of reducing contamination of the object and improving adhesion to the object.

[0110] From the viewpoint of improving adhesion to the object during work, the content of the tackifying resin (C3) in the adhesive resin layer (C) is preferably 1 part by mass or more, more preferably 2 parts by mass or more, even more preferably 3 parts by mass or more, and even more preferably 4 parts by mass or more, when the content of the adhesive resin (C1) in the adhesive resin layer (C) is 100 parts by mass. From the viewpoint of improving the balance between adhesion to the object and adhesiveness at room temperature, the content of the tackifying resin (C3) in the adhesive resin layer (C) is preferably 100 parts by mass or less, more preferably 50 parts by mass or less, even more preferably 25 parts by mass or less, and even more preferably 10 parts by mass or less, when the content of the adhesive resin (C1) in the adhesive resin layer (C) is 100 parts by mass.

[0111] The adhesive resin layer (C) may also contain additives such as plasticizers as other components.

[0112] The lower limit of the total content of adhesive resin (C1), crosslinking agent (C2), tackifying resin (C3), and thermally expandable microspheres in the adhesive resin layer (C) is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more, when the total amount of the adhesive resin layer (C) is taken as 100% by mass. The upper limit is not particularly limited, but for example, it is 100% by mass or less.

[0113] The adhesive resin layer (C) may be a single layer or a multi-layer layer.

[0114] The thickness of the adhesive resin layer (C) is preferably 10 μm or more, more preferably 15 μm or more, even more preferably 20 μm or more, and even more preferably 25 μm or more, from the viewpoint of improving the balance between adhesiveness and thermal release properties. The thickness of the adhesive resin layer (C) is preferably 100 μm or less, more preferably 75 μm or less, even more preferably 50 μm or less, and even more preferably 40 μm or less, from the viewpoint of improving the handling of the adhesive film 10. The thickness of the adhesive resin layer (C) is preferably 10 μm to 100 μm, more preferably 15 μm to 75 μm, even more preferably 20 μm to 50 μm, and even more preferably 25 μm to 40 μm, from the viewpoint of improving the balance of performance in terms of adhesiveness, thermal release properties, and handling properties.

[0115] The adhesive resin layer (C) can be formed, for example, by applying an adhesive coating solution onto the base layer (A), or by transferring the adhesive resin layer (C) formed on the separator onto the base layer (A). Methods for applying the adhesive coating solution include, for example, the roll coater method, the reverse roll coater method, the gravure roll method, the bar coat method, the comma coater method, and the die coater method.

[0116] There are no particular restrictions on the drying conditions for the applied adhesive, but for example, it may be dried at 80-170°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 solution may be heated at 40-80°C for about 5 to 300 hours after it has finished drying.

[0117] The base material layer (A) and the adhesive resin layer (C) may be formed by co-extrusion molding, or they may be formed by laminating (layering) a film-like base material layer (A) and a film-like adhesive resin layer (C).

[0118] [Middle layer (D)] The adhesive film of this embodiment may further include an intermediate layer (D). The intermediate layer (D) is a layer provided as, for example, a surface-absorbing resin layer, an impact-absorbing layer, an anchor coat layer, etc.

[0119] The intermediate layer (D) preferably contains a thermoplastic resin. When the adhesive film of this embodiment is used, for example, as a tape for temporarily fixing electronic components, the intermediate layer (D) more preferably contains one or more selected from the group consisting of polyolefin resins, polystyrene resins, (meth)acrylic resins, urethane resins, silicone resins, polyester resins, polyamide resins, and fluororesins, and even more preferably contains one or more selected from the group consisting of polyolefin resins, polystyrene resins, and (meth)acrylic resins.

[0120] When the adhesive film of this embodiment is used, for example, as a tape for temporarily fixing electronic components, the thickness of the intermediate layer (D) is preferably 5 μm to 100 μm, more preferably 10 μm to 50 μm, and even more preferably 15 μm to 25 μm, from the viewpoint of improving the ability of the adhesive film to absorb unevenness.

[0121] The intermediate layer (D) preferably contains a thermoplastic resin. When the adhesive film of this embodiment is used, for example, in a dicing tape, the intermediate layer (D) more preferably includes one or more selected from the group consisting of olefin resins, ethylene-(meth)acrylic acid ester copolymers, ethylene-vinyl ester copolymers, 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, and polyester-based elastomers. Olefin resins include, for example, one or more selected from the group consisting of ethylene resins, propylene polymers, 1-butene polymers, 4-methyl-1-pentene polymers, ethylene-α-olefin copolymers, ethylene-cyclic olefin copolymers, ethylene-α-olefin-cyclic olefin copolymers, ethylene-α-olefin-unconjugated polyene copolymers, ethylene-α-olefin-conjugated polyene copolymers, ethylene-aromatic vinyl copolymers, ethylene-α-olefin-aromatic vinyl copolymers, and copolymers thereof. Furthermore, the ethylene-based resin includes, for example, one or more types selected from the group consisting of high-density polyethylene resin (HDPE), medium-density polyethylene resin (MDPE), low-density polyethylene resin (LDPE), ultra-low-density polyethylene resin (ULDPE), and linear low-density polyethylene resin (LLDPE). Ethylene-(meth)acrylic acid ester copolymers include, for example, one or more selected from the group consisting of ethylene-(meth)acrylic acid ethyl copolymer, ethylene-(meth)acrylic acid methyl copolymer, ethylene-(meth)acrylic acid propyl copolymer, ethylene-(meth)acrylic acid butyl copolymer, ethylene-(meth)acrylic acid hexyl copolymer, ethylene-(meth)acrylic acid 2-hydroxyethyl copolymer, ethylene-(meth)acrylic acid 2-hydroxypropyl copolymer, and ethylene-(meth)acrylic acid glycidyl copolymer. Ethylene-vinyl ester copolymers include, for example, one or more selected from the group consisting of ethylene-vinyl acetate copolymers, ethylene-vinyl propionate copolymers, ethylene-vinyl butyrate copolymers, and ethylene-vinyl stearate copolymers.

[0122] When the adhesive film of this embodiment is used, for example, in a dicing tape, the intermediate layer (D) more preferably comprises one or more selected from the group consisting of ethylene-α-olefin copolymer and ethylene-vinyl ester copolymer, more preferably comprises one or more selected from the group consisting of ethylene-α-olefin copolymer and ethylene-vinyl acetate copolymer, and more preferably comprises ethylene-vinyl acetate copolymer.

[0123] When the adhesive film of this embodiment is used, for example, as a dicing tape, the content of vinyl acetate units in the ethylene-vinyl acetate copolymer in the adhesive film of this embodiment is preferably 10% to 35% by mass, more preferably 12% to 30% by mass, and even more preferably 15% to 25% by mass, when the total amount of the ethylene-vinyl acetate copolymer is 100% by mass, from the viewpoint of improving the balance of crosslinkability, flexibility, weather resistance, and transparency. The vinyl acetate content can be measured, for example, in accordance with JIS K6730:1994.

[0124] When the adhesive film of this embodiment is used, for example, in a dicing tape, the number of carbon atoms in the α-olefin of the ethylene-α-olefin copolymer used as the thermoplastic resin in the adhesive film of this embodiment is preferably 3 to 20, more preferably 3 to 10, and even more preferably 3 to 8. The α-olefin used in the ethylene-α-olefin copolymer includes, for example, one or more selected from the group consisting of propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3,3-dimethyl-1-butene, 4-methyl-1-pentene, 1-octene, 1-decene, and 1-dodecene. The α-olefin used in the ethylene-α-olefin copolymer preferably includes one or more selected from the group consisting of propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, and 1-octene, from the viewpoint of availability. The ethylene-α-olefin copolymer may be a random copolymer or a block copolymer, but from the viewpoint of flexibility, a random copolymer is preferred.

[0125] The intermediate layer (D) may also contain additives such as plasticizers as other components. The intermediate layer (D) may be a single layer or a multi-layer layer.

[0126] <Physical properties of adhesive films> The physical properties of the adhesive film of this embodiment will be described below.

[0127] The ratio (Ra2 / Ra1) (hereinafter also referred to as the ratio (Ra2 / Ra1)) of the adhesive film of this embodiment, from the arithmetic mean roughness Ra1 (hereinafter also referred to as arithmetic mean roughness Ra1) obtained by the above-mentioned (method 1) after the above-mentioned (process 1) to the arithmetic mean roughness Ra2 (hereinafter also referred to as arithmetic mean roughness Ra2) obtained by the above-mentioned (method 2) after the above-mentioned (process 1), will be explained.

[0128] The ratio (Ra2 / Ra1) is preferably 0.40 or higher, more preferably 0.45 or higher, more preferably 0.50 or higher, even more preferably 0.55 or higher, even more preferably 0.60 or higher, even more preferably 0.65 or higher, even more preferably 0.70 or higher, even more preferably 0.75 or higher, even more preferably 0.80 or higher, and even more preferably 0.85 or higher, from the viewpoint of reducing contamination of the target object. There is no particular upper limit to the ratio (Ra2 / Ra1), but it may be 2.0 or less, 1.5 or less, 1.2 or less, or 1.0 or less. The ratio (Ra2 / Ra1) is preferably 0.40 to 2.0, more preferably 0.45 to 1.5, even more preferably 0.50 to 1.2, even more preferably 0.55 to 1.0, even more preferably 0.60 to 1.0, even more preferably 0.65 to 1.0, even more preferably 0.70 to 1.0, even more preferably 0.75 to 1.0, even more preferably 0.80 to 1.0, and even more preferably 0.85 to 1.0, from the viewpoint of reducing contamination of the target object. More specifically, the method used in the examples can be employed to measure the ratio (Ra2 / Ra1).

[0129] The ratio (Ra2 / Ra1) can be adjusted, for example, by adjusting the type of adhesive resin layer (C), the composition of the adhesive resin layer (C), the method of forming the adhesive resin layer (C), the thickness of the adhesive resin layer (C), the type of thermally expandable microspheres, etc.

[0130] The arithmetic mean roughness Ra1 of the adhesive film of this embodiment will be described below.

[0131] The arithmetic mean roughness Ra1 is preferably 5.0 μm or more, more preferably 7.0 μm or more, even more preferably 9.0 μm or more, even more preferably 9.5 μm or more, and even more preferably 10.0 μm or more, from the viewpoint of further reducing contamination of the target object. There is no particular upper limit to the arithmetic mean roughness Ra1, but it may be, for example, 30.0 μm or less, 20.0 μm or less, 15.0 μm or less, or 13.0 μm or less. The arithmetic mean roughness Ra1 is preferably 5.0 μm to 30.0 μm, more preferably 7.0 μm to 20.0 μm, even more preferably 9.0 μm to 15.0 μm, even more preferably 9.5 μm to 15.0 μm, and even more preferably 10.0 μm to 13.0 μm, from the viewpoint of further reducing contamination of the target object. More specifically, the method used in the examples can be employed to measure the arithmetic mean roughness Ra1.

[0132] The arithmetic mean roughness Ra1 can be adjusted, for example, by adjusting the type of adhesive resin layer (C), the composition of the adhesive resin layer (C), the method of forming the adhesive resin layer (C), the thickness of the adhesive resin layer (C), the type of thermally expandable microspheres, etc.

[0133] The arithmetic mean roughness Ra2 of the adhesive film of this embodiment will be described below.

[0134] The arithmetic mean roughness Ra2 is preferably 2.0 μm or more, more preferably 4.0 μm or more, even more preferably 6.0 μm or more, even more preferably 8.0 μm or more, even more preferably 8.5 μm or more, even more preferably 9.0 μm or more, and even more preferably 9.5 μm or more, from the viewpoint of further reducing contamination of the target object. There is no particular upper limit to the arithmetic mean roughness Ra2, but it may be, for example, 30.0 μm or less, 20.0 μm or less, 15.0 μm or less, or 12.0 μm or less. From the viewpoint of further reducing contamination of the target object, the arithmetic mean roughness Ra2 is preferably 2.0 μm to 30.0 μm, more preferably 4.0 μm to 20.0 μm, even more preferably 6.0 μm to 15.0 μm, even more preferably 8.0 μm to 12.0 μm, even more preferably 8.5 μm to 12.0 μm, even more preferably 9.0 μm to 12.0 μm, and even more preferably 9.5 μm to 12.0 μm. More specifically, the method used in the examples can be employed to measure the arithmetic mean roughness Ra2.

[0135] The arithmetic mean roughness Ra2 can be adjusted, for example, by adjusting the type of adhesive resin layer (C), the composition of the adhesive resin layer (C), the method of forming the adhesive resin layer (C), the thickness of the adhesive resin layer (C), the type of thermally expandable microspheres, etc.

[0136] The number of foreign objects observed in the adhesive film of this embodiment according to the following (method of observing foreign objects) will be explained.

[0137] The number of foreign objects observed according to the following (method of observing foreign objects) is preferably less than 10, more preferably less than 7, even more preferably less than 5, even more preferably less than 4, and even more preferably less than 3, from the viewpoint of further reducing contamination of the object. There is no particular lower limit to the number of foreign objects; for example, it may be zero or more, one or more, or two or more.

[0138] (Method for observing foreign objects) Structure 1 is fabricated by attaching an adhesive resin layer (C) of an adhesive film to a silicon wafer. Next, structure 1 is heated at 150°C for 1 hour. Next, structure 1 is heated at 200°C for 60 seconds. Next, the adhesive film is peeled off from the silicon wafer. Then, the number of foreign matter originating from the adhesive film present in a 1 cm × 1 cm area on the surface of the silicon wafer is observed using a microscope at a magnification of 500x. Here, the method for observing foreign matter can be more specifically the method described in the examples.

[0139] The evaluation values ​​of particles measured according to the following (method for evaluating particles) for the adhesive film of this embodiment will be described below.

[0140] The particle evaluation value observed according to the following (Particle Evaluation Method) is preferably less than 10,000, more preferably less than 5,000, even more preferably less than 2,000, even more preferably less than 1,000, and even more preferably less than 500, from the viewpoint of further reducing contamination of the target object. There are no particular restrictions on the lower limit of the particle evaluation value; for example, it may be 0 or greater, 10 or greater, or 100 or greater.

[0141] (Method for evaluating particles) A silicon wafer is heated at 150°C for 1 hour. Next, the silicon wafer is cooled in a cleanroom at 23°C for 30 minutes. Then, the silicon wafer is heated again at 200°C for 60 seconds. Finally, the number of particles on the surface of the silicon wafer is counted using a wafer surface inspection device. The total number of particles at this time is defined as the measured value P2. Next, a structure 2 is fabricated by attaching an adhesive resin layer (C) of an adhesive film to a silicon wafer. Then, structure 2 is heated at 150°C for 1 hour. Next, structure 2 is cooled by standing in a clean room at 23°C for 30 minutes. Next, structure 2 is heated at 200°C for 60 seconds. Next, the adhesive film is peeled off from the silicon wafer. Then, the particles on the surface of the silicon wafer are counted using a wafer surface inspection device. The total number of particles at this time is defined as the measured value P1. Next, the value obtained by subtracting the measured value P2 from the measured value P1 (P1 - P2) is taken as the evaluation value of the particle. Here, the particle evaluation method can be more specifically the method described in the examples.

[0142] <Structure of adhesive film> Several examples of the structure of the adhesive film 10 in this embodiment will be described. In the adhesive film 10 of this embodiment, the surface on the side with the adhesive resin layer (C) is in contact with the workpiece 20. In this case, the workpiece 20 is located on the second surface A2 side of the base material layer (A) of the adhesive film 10, and the support member 30 is located on the first surface A1 side of the base material layer (A). The adhesive film 10 of this embodiment may have a structure like that shown in Figures 4 to 7 below.

[0143] In Figure 4, the adhesive film 10 is in contact with the support member 30 on the base material layer (A) side and with the workpiece 20 on the adhesive resin layer (C) side. The adhesive film 10 in Figure 4 temporarily fixes the workpiece 20 in place with the adhesive resin layer (C). The adhesive film 10 in Figure 4 may be temporarily fixed to the support member 30 by pressing it against the support member 30 with, for example, a fixing ring, or it may be temporarily fixed to the support member 30 by being sucked onto the support member 30 with a vacuum chuck or the like. Note that in Figure 4, the members for temporarily fixing the adhesive film 10 to the support member 30 are not shown.

[0144] The adhesive film 10 in Figure 4 may optionally further include an intermediate layer (D) between the base layer (A) and the adhesive resin layer (C). Note that the intermediate layer (D) is not shown in Figure 4.

[0145] The adhesive film 10 in Figure 5 further comprises an adhesive resin layer (B) on the first surface A1 side of the base layer (A). In this case, the base layer (A) is located between the adhesive resin layer (B) and the adhesive resin layer (C).

[0146] The adhesive film 10 in Figure 5 is in contact with the support member 30 on the side with the adhesive resin layer (B) and with the workpiece 20 on the side with the adhesive resin layer (C). In Figure 5, the adhesive film 10 temporarily fixes the workpiece 20 with an adhesive resin layer (C). Furthermore, the adhesive film 10 in Figure 5 is temporarily fixed to the support member 30 with an adhesive resin layer (B).

[0147] The adhesive film 10 in Figure 5 may further include an intermediate layer (D) as needed, selected from at least one of the following: between the base layer (A) and the adhesive resin layer (B), and between the base layer (A) and the adhesive resin layer (C). Note that the intermediate layer (D) is not shown in Figure 5. Furthermore, the adhesive film 10 in Figure 5 may optionally include intermediate layers (D) between the base layer (A) and the adhesive resin layer (B), and between the base layer (A) and the adhesive resin layer (C). In this case, the intermediate layer (D) located between the base layer (A) and the adhesive resin layer (B) may have a different configuration from, or the same configuration as, the intermediate layer (D) located between the base layer (A) and the adhesive resin layer (C).

[0148] The adhesive film 10 in Figure 6 is an example of the adhesive film 10 in Figure 5, in which an intermediate layer (D) is further provided between the base layer (A) and the adhesive resin layer (C).

[0149] The adhesive film 10 in Figure 7 is an example of the adhesive film 10 in Figure 4, in which an additional adhesive resin layer (C) is provided on the first surface A1 side of the base material layer (A). In this case, the adhesive resin layer (C) on the first surface A1 side of the base material layer (A) (hereinafter also referred to as the adhesive resin layer (CA1)) may have a different configuration from or the same configuration as the adhesive resin layer (C) on the second surface A2 side of the base material layer (A) (hereinafter also referred to as the adhesive resin layer (CA2)). The adhesive film 10 in Figure 7 is in contact with the support member 30 on the adhesive resin layer (CA1) side and with the workpiece 20 on the adhesive resin layer (CA2) side. In Figure 7, the adhesive film 10 temporarily fixes the workpiece 20 with an adhesive resin layer (CA2). Furthermore, the adhesive film 10 in Figure 7 is temporarily fixed to the support member 30 with an adhesive resin layer (CA1).

[0150] The adhesive film 10 in Figure 7 may further include an intermediate layer (D) selected from at least one of the following: between the base layer (A) and the adhesive resin layer (CA1), and between the base layer (A) and the adhesive resin layer (CA2), if necessary. Note that the intermediate layer (D) is not shown in Figure 7. Furthermore, the adhesive film 10 in Figure 7 may optionally include intermediate layers (D) between the base material layer (A) and the adhesive resin layer (CA1), and between the base material layer (A) and the adhesive resin layer (CA2). In this case, the intermediate layer (D) located between the base material layer (A) and the adhesive resin layer (CA1) may have a different configuration from, or the same configuration as, the intermediate layer (D) located between the base material layer (A) and the adhesive resin layer (CA2).

[0151] <Method for manufacturing adhesive film> Next, an example of a method for manufacturing the adhesive film 10 of this embodiment will be described. The adhesive film 10 of this embodiment can be formed, for example, by applying an adhesive resin layer (C) onto a base layer (A), or by transferring an adhesive resin layer (C) formed on a separator onto the base layer (A). Furthermore, the adhesive film 10 of this embodiment may be formed by laminating (layering) a base material layer (A) and an adhesive resin layer (C) in this order. Alternatively, the adhesive film 10 of this embodiment may be formed by co-extrusion molding of the base material layer (A) and the adhesive resin layer (C) in this order.

[0152] One method for applying an adhesive resin layer (C) onto a substrate layer (A) is to apply an adhesive coating liquid capable of forming an adhesive resin layer (C). Examples of methods for applying the adhesive coating liquid include the roll coater method, the reverse roll coater method, the gravure roll method, the bar coat method, the comma coater method, and the die coater method. There are no particular restrictions on the drying conditions of the adhesive coating liquid, but it is preferably dried at a temperature range of 80 to 200°C for 10 seconds to 10 minutes, and more preferably at a temperature range of 80 to 170°C for 15 seconds to 5 minutes. In the adhesive coating solution, in order to sufficiently promote the crosslinking reaction between the crosslinking agent and the adhesive resin, the solution may be heated at a temperature range of 40 to 80°C for about 5 to 300 hours after the drying of the adhesive coating solution is complete.

[0153] If the adhesive film 10 of this embodiment further comprises an adhesive resin layer (B), the adhesive film 10 of this embodiment can be formed, for example, by applying the adhesive resin layer (B) and the adhesive resin layer (C) to a base layer (A), or by transferring the adhesive resin layer (B) and the adhesive resin layer (C) formed on a separator to the base layer (A). Furthermore, if the adhesive film 10 of this embodiment further comprises an adhesive resin layer (B), the adhesive film 10 of this embodiment may be formed by laminating (layering) the adhesive resin layer (B), the base layer (A), and the adhesive resin layer (C) in this order. Alternatively, the adhesive film 10 of this embodiment may be formed by co-extrusion molding of the adhesive resin layer (B), the base layer (A), and the adhesive resin layer (C) in this order.

[0154] If the adhesive film 10 of this embodiment further comprises an intermediate layer (D), the adhesive film 10 of this embodiment can be formed, for example, the adhesive film 10 shown in Figure 6, by laminating (layering) an adhesive resin layer (B), a base layer (A), an intermediate layer (D), and an adhesive resin layer (C) in this order; by co-extruding an adhesive resin layer (B), a base layer (A), an intermediate layer (D), and an adhesive resin layer (C) in this order; by laminating (layering) the base layer (A) and the intermediate layer (D) and then applying the adhesive resin layer (B) and the adhesive resin layer (C), respectively; or by laminating (layering) the base layer (A) and the intermediate layer (D) and then transferring the adhesive resin layer (B) and the adhesive resin layer (C), respectively, that have been formed on a separator.

[0155] If the adhesive film 10 of this embodiment further comprises an adhesive resin layer (CA1) (i.e., the adhesive film 10 comprises an adhesive resin layer (CA1) and an adhesive resin layer (CA2)), the adhesive film 10 of this embodiment can be formed, for example, by applying the adhesive resin layer (CA1) and the adhesive resin layer (CA2) to a base layer (A), or by transferring the adhesive resin layer (CA1) and the adhesive resin layer (CA2) formed on a separator to the base layer (A). Furthermore, if the adhesive film 10 of this embodiment further comprises an adhesive resin layer (CA1), the adhesive film 10 of this embodiment may be formed by laminating (layering) the adhesive resin layer (CA1), the base layer (A), and the adhesive resin layer (CA2) in this order. Alternatively, the adhesive film 10 of this embodiment may be formed by co-extrusion molding of the adhesive resin layer (CA1), the base layer (A), and the adhesive resin layer (CA2) in this order.

[0156] The embodiments of the present invention have been described above, but these are merely examples, and various other configurations can also be adopted. Furthermore, the present invention is not limited to the embodiments described above, and any modifications, improvements, etc., that do not impair the effects of the present invention are included in the present invention. [Examples]

[0157] This embodiment will be described in detail below with reference to examples and other relevant information. However, this embodiment is not limited in any way to the descriptions of these examples.

[0158] The details of the materials used to produce the adhesive film are as follows:

[0159] <Adhesive resin solution SB1> To deionized pure water, 0.5 parts by mass of 4,4'-azobis-4-cyanovaleric acid (manufactured by Otsuka Chemical Co., Ltd., trade name: ACVA) as a polymerization initiator, 74.3 parts by mass of n-butyl acrylate, 13.7 parts by mass of methyl methacrylate, 9 parts by mass of 2-hydroxyethyl methacrylate, and 3 parts by mass of a polymerizable 1-propenyl group introduced to the benzene ring of the ammonium salt of the sulfate ester of polyoxyethylene nonylphenyl ether (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon HS-1025) were added. Emulsification polymerization was carried out at 70-72°C for 8 hours under stirring to obtain an acrylic resin emulsion. This was neutralized with aqueous ammonia (pH=7.0) to obtain a sticky resin solution SB1 with a solid content concentration of 42.5%.

[0160] <Adhesive resin solution SB2> To deionized pure water, 0.5 parts by mass of ammonium persulfate, 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, 1 part by mass of polytetramethylene glycol diacrylate (manufactured by Nippon Oil & Fats Co., Ltd., trade name: ADT-250), and 2 parts by mass of polyoxyethylene nonylphenyl ether sulfate ammonium salt with a polymerizable 1-propenyl group introduced to the benzene ring (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon HS-1025) were added as polymerization initiators. Emulsification polymerization was carried out at 70-72°C for 8 hours under stirring to obtain an acrylic resin emulsion. This was neutralized with ammonia water (pH=7.0) to obtain a sticky resin solution SB2 with a solid content concentration of 56.5%.

[0161] <Adhesive coating solution B1> Adhesive coating solution B1 was obtained by mixing 57.4 parts by mass of adhesive resin solution SB1, 42.6 parts by mass of adhesive resin solution SB2, 0.4 parts by mass of dimethylethanolamine, and 3.4 parts by mass of an epoxy compound (manufactured by Nagase ChemteX, Ex-1610) which is a crosslinking agent.

[0162] <Adhesive resin solution SC1> To a mixed solvent containing ethyl acetate and toluene, 0.536 parts by mass of t-butyl peroxy-2-ethylhexanoate (manufactured by Nippon Oil & Fats Co., Ltd., trade name: Perbutyl O®), 34.9 parts by mass of 2-ethylhexyl acrylate, 41 parts by mass of n-butyl acrylate, 14.7 parts by mass of ethyl acrylate, and 9.4 parts by mass of 2-hydroxyethyl methacrylate were added as polymerization initiators. Solution polymerization was carried out at 83-87°C for 11 hours under stirring to obtain an acrylic resin solution with a solid content of 45% by mass. This was designated as adhesive resin solution SC1.

[0163] <Adhesive coating liquid C1> 100 parts by mass of adhesive resin solution SC1 and 0.9 parts by mass of isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals, Inc., trade name: Olestar P49-75S) (2 parts by mass per 100 parts by mass of adhesive resin) were mixed, and the solid content concentration was adjusted to 40% with ethyl acetate to obtain adhesive coating solution C1.

[0164] <Adhesive coating solution C2> Adhesive coating solution C2 was prepared by mixing 100 parts by mass of adhesive resin solution SC1, 2.25 parts by mass of polymerized rosin ester tackifier (manufactured by Arakawa Chemical Industries, Ltd., trade name: Pencel D-125) (5 parts by mass per 100 parts by mass of adhesive resin), 1.2 parts by mass of isocyanate crosslinking agent (manufactured by Mitsui Chemicals, Inc., trade name: Olestar P49-75S) (2.67 parts by mass per 100 parts by mass of adhesive resin), and 6.75 parts by mass of thermosetting resin-containing thermally expandable microspheres (manufactured by Sekisui Chemical Co., Ltd., trade name: Advancell EM701) (15 parts by mass per 100 parts by mass of adhesive resin), and adjusting the solid content concentration to 30% with ethyl acetate. Furthermore, for thermosetting resin-containing thermally expandable microspheres (Advancell EM701), the particle size D is measured at 50% in the volume-based cumulative frequency distribution curve as measured by a laser diffraction scattering particle size distribution analyzer. 50 The size was 19.8 μm.

[0165] <Adhesive coating liquid C3> Adhesive coating solution C3 was prepared by mixing 100 parts by mass of adhesive resin solution SC1, 2.25 parts by mass of polymerized rosin ester tackifier (manufactured by Arakawa Chemical Industries, Ltd., trade name: Pencel D-125) (5 parts by mass per 100 parts by mass of adhesive resin), 1.2 parts by mass of isocyanate crosslinking agent (manufactured by Mitsui Chemicals, Inc., trade name: Olestar P49-75S) (2.67 parts by mass per 100 parts by mass of adhesive resin), and 11.25 parts by mass of thermosetting resin-containing thermally expandable microspheres (manufactured by Sekisui Chemical Co., Ltd., trade name: Advancell EM701) (25 parts by mass per 100 parts by mass of adhesive resin), and adjusting the solid content concentration to 30% with ethyl acetate. Furthermore, for thermosetting resin-containing thermally expandable microspheres (Advancell EM701), the particle size D is measured at 50% in the volume-based cumulative frequency distribution curve as measured by a laser diffraction scattering particle size distribution analyzer. 50 The size was 19.8 μm.

[0166] <Adhesive coating solution C4> Adhesive coating solution C4 was prepared by mixing 100 parts by mass of adhesive resin solution SC1, 2.25 parts by mass of polymerized rosin ester tackifier (manufactured by Arakawa Chemical Industries, Ltd., trade name: Pencel D-125) (5 parts by mass per 100 parts by mass of adhesive resin), 1.2 parts by mass of isocyanate crosslinking agent (manufactured by Mitsui Chemicals, Inc., trade name: Olestar P49-75S) (2.67 parts by mass per 100 parts by mass of adhesive resin), and 6.75 parts by mass of thermosetting resin-free thermally expandable microspheres (manufactured by Sekisui Chemical Co., Ltd., trade name: Advancell EM-504) (15 parts by mass per 100 parts by mass of adhesive resin), and adjusting the solid content concentration to 30% with ethyl acetate. Furthermore, for thermally expandable microspheres (Advancell EM-504) that do not contain thermosetting resin, the particle size D is measured at 50% in the volume-based cumulative frequency distribution curve measured by a laser diffraction scattering particle size distribution analyzer. 50 The size was 17.6 μm.

[0167] [Example 1] A 10 μm thick adhesive resin layer (B) was formed on a polyethylene terephthalate (PET) film (38 μm thick), which served as the base layer (A), by drying adhesive coating liquid B1. Next, a 20 μm thick intermediate layer (D) was formed on the surface of the PET film opposite to the adhesive resin layer (B) by drying adhesive coating liquid C1. On top of this, a 30 μm thick heat-peelable adhesive resin layer (C) was formed by drying adhesive coating liquid C2 to obtain an adhesive film.

[0168] [Example 2] A 10 μm thick adhesive resin layer (B) was formed on a polyethylene terephthalate (PET) film (38 μm thick), which served as the base layer (A), by drying adhesive coating liquid B1. Next, a 20 μm thick intermediate layer (D) was formed on the surface of the PET film opposite to the adhesive resin layer (B) by drying adhesive coating liquid C1. On top of this, a 30 μm thick heat-peelable adhesive resin layer (C) was formed by drying adhesive coating liquid C3 to obtain an adhesive film.

[0169] [Comparative Example 1] A 10 μm thick adhesive resin layer (B) was formed on a polyethylene terephthalate (PET) film (38 μm thick), which served as the base layer (A), by drying adhesive coating liquid B1. Next, a 20 μm thick intermediate layer (D) was formed on the surface of the PET film opposite to the adhesive resin layer (B) by drying adhesive coating liquid C1. On top of this, a 30 μm thick heat-peelable adhesive resin layer (C) was formed by drying adhesive coating liquid C4 to obtain an adhesive film.

[0170] (Examples 1-2, Comparative Example 1) The physical properties of the adhesive films in each example were measured and evaluated using the following method. The measurement and evaluation results are shown in Table 1.

[0171] <Method for measuring arithmetic mean roughness Ra1> The adhesive film for each example was subjected to the following (Process 1). Subsequently, the arithmetic mean roughness Ra1 of the adhesive film for each example was measured according to the following (Method 1).

[0172] (Process 1) Structure A was fabricated by attaching the adhesive resin layer (B) side of a 5cm x 5cm adhesive film to a 30cm x 30cm, 1.5mm thick SUS substrate (material: SUS304). Next, structure A was heated at 150°C for 1 hour using a forced-air constant-temperature incubator (product name: DN63H, manufactured by Yamato Scientific Co., Ltd.). Next, structure A was placed on a hot plate with the SUS substrate side facing down, and structure A was heated using the hot plate at 200°C for 60 seconds.

[0173] (Method 1) The arithmetic mean roughness Ra of the adhesive resin layer (C) was measured in accordance with JIS B 0601:2013 using a surface roughness measuring instrument (product name: Dektak XTL, manufactured by BRUKER). This measurement was performed under the condition of a sample size n=2. The mean value of each sample was defined as the arithmetic mean roughness Ra1.

[0174] <Method for measuring arithmetic mean roughness Ra2> The above (Process 1) was performed on the adhesive film of each example. Subsequently, the arithmetic mean roughness Ra2 was measured for each adhesive film according to the following (Method 2).

[0175] (Method 2) A 1000g weight with a 1cm × 1cm surface was placed on the adhesive resin layer (C) of structure A after the above (processing 1), so that the 1cm × 1cm surface of the weight was in contact with the 1cm × 1cm surface of the adhesive resin layer (C) including the center, and the structure was left standing at 200°C for 1 hour. The 1000g weight with a 1cm × 1cm surface was made by placing a cylindrical weight on top of a 1cm × 1cm × 1cm weight (material: SUS304) so ​​that the total mass of the weight and the cylindrical weight was 1000g. Next, after removing the weight from structure A, structure A was cooled at 23°C for 5 minutes. Next, using a surface roughness measuring instrument (product name: Dektak XTL, manufactured by BRUKER), the arithmetic mean roughness Ra of the portion of the adhesive resin layer (C) that was in contact with the weight was measured in accordance with JIS B 0601:2013. This measurement was performed under the condition of a sample size n=2. The average value of each sample was defined as the arithmetic mean roughness Ra2.

[0176] <Method for evaluating adhesive residue> The following procedures were performed using the adhesive film from each example. Structure 1 was fabricated by attaching an adhesive resin layer (C) of an adhesive film to a silicon wafer (product name: 4-inch P-type Bare Si Wafer, manufactured by Shin-Etsu Chemical Co., Ltd.). Next, structure 1 was heated in an oven at 150°C for 1 hour. Then, using a hot plate, structure 1 was heated at 200°C for 60 seconds with the silicon wafer side of structure 1 in contact with the hot plate. Next, the adhesive film was removed from the silicon wafer, and the number of foreign matter originating from the adhesive film present in a 1 cm × 1 cm area on the surface of the silicon wafer was observed at room temperature using a microscope (product name: VHX-5000, manufactured by Keyence Corporation) at a magnification of 500x. All of the above operations were performed in a Class 10,000 cleanroom. This evaluation was performed under the condition of a sample size of n=3. The average value for each sample was used as the number of foreign objects. The number of foreign objects was evaluated as A if it was less than 5, B if it was 5 or more but less than 10, and C if it was 10 or more.

[0177] <Method for evaluating particles> The following procedures were performed using the adhesive film from each example. First, particle measurements were performed on a silicon wafer without attaching an adhesive film. Specifically, a silicon wafer (product name: 4-inch P-type Bare Si Wafer, manufactured by Shin-Etsu Chemical Co., Ltd.) was heated at 150°C for 1 hour. Next, the silicon wafer was cooled in a cleanroom at 23°C for 30 minutes. Then, the silicon wafer was heated at 200°C for 60 seconds. Next, particles on the surface of the silicon wafer were counted using a wafer surface inspection device (product name: WM-7S, manufactured by Takano Corporation) under the following conditions (settings). The total number of particles at this time was defined as the measured value P2. Next, structure 2 was fabricated by attaching an adhesive resin layer (C) of an adhesive film to a silicon wafer (product name: 4-inch P-type Bare Si Wafer, manufactured by Shin-Etsu Chemical Co., Ltd.). Next, structure 2 was heated at 150°C for 1 hour. Next, structure 2 was cooled by standing in a clean room at 23°C for 30 minutes. Next, structure 2 was heated at 200°C for 60 seconds. Next, the adhesive film was peeled off the silicon wafer. Next, the particles on the surface of the silicon wafer were counted using a wafer surface inspection device (product name: WM-7S, manufactured by Takano Corporation) under the following conditions (settings). The total number of particles at this time was defined as the measured value P1. Next, the value obtained by subtracting the measured value P2 from the measured value P1 (P1 - P2) was taken as the value for each sample. All of the above operations were performed in a Class 10,000 cleanroom. This evaluation was performed under the condition of a sample size of n=3. The average value of each sample was used as the evaluation value for the particle. Particle evaluation values ​​were rated as follows: A if less than 2,000, B if between 2,000 and 10,000, and C if 10,000 or more.

[0178] (setting) Measurement mode: High-resolution Measurement type: Standard measurement Transfer: None Map ORG: Center

[0179] [Table 1]

[0180] This application claims priority based on Japanese Patent Application No. 2024-168507, filed on 27 September 2024, and incorporates all of its disclosures herein. [Explanation of Symbols]

[0181] 10 Adhesive film 20. Object to be processed 21 Electronic Components 22 Thin glass substrate 23 Electronic Components 30 Support member 31 Support substrate 40. Workpiece after processing 41 Electronic Components 42 Electronic Components 100 structures 200 structures 300 structures A Base material layer A1 Page 1 A2 2nd side B Adhesive resin layer C Adhesive resin layer CA1 Adhesive resin layer CA2 adhesive resin layer D Middle layer

Claims

1. A step of preparing a structure comprising an adhesive film having a base layer (A) and an adhesive resin layer (C), and a workpiece temporarily fixed to the adhesive resin layer (C), The process includes processing the object to be processed which is temporarily fixed to the adhesive resin layer (C), The adhesive resin layer (C) contains thermally expandable microspheres, The arithmetic mean roughness Ra of the adhesive film after the following (processing 1) is obtained by the following (method 1). １ The arithmetic mean roughness Ra obtained by the following method (2) after performing the following process (1) is ２ Ratio (Ra ２ / Ra １ A method for manufacturing an electronic device, wherein the coefficient of (Process 1) Structure A is fabricated by attaching the side of the adhesive film opposite to the adhesive resin layer (C) of a 5cm x 5cm adhesive film to a SUS substrate measuring 30cm x 30cm and 1.5mm thick. Next, the structure A is heated at 150°C for 1 hour using a forced-air constant-temperature incubator. Next, the structure A is placed on the hot plate with the SUS substrate side facing downwards, and the structure A is heated using the hot plate at 200°C for 60 seconds. (Method 1) Using a surface roughness measuring instrument, the arithmetic mean roughness Ra of the adhesive resin layer (C) is determined in accordance with JIS B 0601:2013. １ Measure. (Method 2) A 1000g weight having a 1cm x 1cm surface is placed on the adhesive resin layer (C) of the structure A such that the 1cm x 1cm surface of the weight is in contact with the 1cm x 1cm surface of the adhesive resin layer (C) including the center, and the structure is left standing at 200°C for 1 hour. Next, after removing the weight from the structure A, the structure A is cooled at 23°C for 5 minutes. Next, using a surface roughness measuring instrument, the arithmetic mean roughness Ra of the portion of the adhesive resin layer (C) that was in contact with the weight is determined in accordance with JIS B 0601:2013. ２ Measure.

2. The arithmetic mean roughness Ra １ A method for manufacturing an electronic device according to claim 1, wherein the particle size is 5.0 μm or larger.

3. The arithmetic mean roughness Ra ２ A method for manufacturing an electronic device according to claim 1 or 2, wherein the particle size is 2.0 μm or larger.

4. The method for manufacturing an electronic device according to claim 1 or 2, wherein the thermally expandable microspheres include a thermosetting resin.

5. The aforementioned thermally expandable microsphere comprises a shell and a volatile expanding agent within the shell. The method for manufacturing an electronic device according to claim 4, wherein the shell includes the thermosetting resin.

6. The method for manufacturing an electronic device according to claim 4, wherein the curing temperature of the thermosetting resin is equal to or greater than the foaming temperature of the thermally expandable microspheres.

7. The method for manufacturing an electronic device according to claim 1 or 2, wherein the foaming temperature of the thermally expandable microspheres is 160°C or higher.

8. The method for manufacturing an electronic device according to claim 1 or 2, wherein the adhesive resin layer (C) is a layer whose adhesive strength decreases when heated.

9. The method for manufacturing an electronic device according to claim 1 or 2, wherein the adhesive resin layer (C) comprises one or more selected from the group consisting of (meth)acrylic adhesive resins, silicone adhesive resins, urethane adhesive resins, olefin adhesive resins, and styrene adhesive resins.

10. A method for manufacturing an electronic device according to claim 1 or 2, wherein the content of the thermally expandable microspheres in the adhesive resin layer (C) is 5% by mass or more and 50% by mass or less when the total amount of the adhesive resin layer (C) is 100% by mass.

11. In the volume-based cumulative frequency distribution curve of the thermally expandable microspheres measured by the laser diffraction / scattering particle size distribution measuring device, the particle diameter D at the time when the cumulative frequency is 50% ５０ is 5 μm or more and 40 μm or less, The method for manufacturing an electronic device according to claim 1 or 2.

12. The method for manufacturing an electronic device according to claim 1 or 2, wherein the substrate layer (A) comprises one or more selected from the group consisting of polypropylene, polyethylene terephthalate, polyethylene naphthalate, polyamide, polyimide, and polyetheretherketone.

13. The method for manufacturing an electronic device according to claim 1 or 2, wherein the thickness of the adhesive resin layer (C) is 10 μm or more and 100 μm or less.

14. A method for manufacturing an electronic device according to claim 1 or 2, wherein the number of foreign objects observed in the adhesive film according to the following (method for observing foreign objects) is less than 10. (Method for observing foreign objects) A structure 1 is fabricated by attaching the adhesive resin layer (C) of the adhesive film to a silicon wafer. Next, the structure 1 is heated at 150°C for 1 hour. Next, the structure 1 is heated at 200°C for 60 seconds. Next, the adhesive film is peeled off from the silicon wafer. Next, the number of foreign matter originating from the adhesive film present in a 1 cm × 1 cm area on the surface of the silicon wafer is observed using a microscope at a magnification of 500x.

15. The invention further comprises an adhesive resin layer (B) capable of temporarily fixing at least one of an electronic component and a substrate, The method for manufacturing an electronic device according to claim 1 or 2, wherein the base material layer (A) is located between the adhesive resin layer (B) and the adhesive resin layer (C).

16. The method for manufacturing an electronic device according to claim 15, wherein the thickness of the adhesive resin layer (B) is 1 μm or more and 40 μm or less.

17. The method for manufacturing an electronic device according to claim 15, further comprising an intermediate layer (D) between the base material layer (A) and the adhesive resin layer (B), and at least one of the layers between the base material layer (A) and the adhesive resin layer (C).

18. The method for manufacturing an electronic device according to claim 17, wherein the thickness of the intermediate layer (D) is 5 μm or more and 100 μm or less.

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