Method for manufacturing electronic device

Abstract

This method for manufacturing an electronic device comprises: a step for preparing a structure (100) that includes an adhesive film (10), provided with a base material layer (A) and an adhesive resin layer (C), and an object to be processed (20) that is temporarily fixed to the adhesive resin layer (C); and a step for processing the object to be processed (20) that is temporarily fixed to the adhesive resin layer (C), the adhesive resin layer (C) including thermally expandable microspheres containing a thermosetting resin.

Description

Method for manufacturing an electronic device

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

[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 aims to provide a dicing tape and a DDAF that are suitable for widening the separation distance while suppressing the floating of a semiconductor chip with a DAF 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), and are suitable for realizing good pick-up performance in the pick-up process. The dicing tape has a laminated structure including a base material and an adhesive layer, and for a 20 mm wide dicing tape test piece, the ratio of the second tensile stress that occurs 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 to the first tensile stress that occurs 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 is 1.4 or more.

[0004] Patent Document 2 aims to solve the problems that the chip is not held due to the pressure during resin encapsulation and shifts from the designated position, or that the package is damaged due to the curing of the encapsulant or the strong adhesion to the chip surface due to heat when peeling the heat-resistant adhesive sheet for manufacturing a semiconductor device. When resin-encapsulating a substrate-less semiconductor chip, a heat-resistant adhesive sheet for manufacturing a semiconductor device used by being adhered is described. The heat-resistant adhesive sheet has a base material layer and an adhesive layer, and the adhesive layer has an adhesive force to SUS304 of 0.5 N / 20 mm or more after bonding, and cures due to the stimulation received until the completion of the resin encapsulation process, and the peeling force against the package is 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, 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 to clean 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 heat-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.

[0007] Japanese Patent Publication No. 2019-16634, Japanese Patent Publication No. 2011-134811, International Publication No. 2010 / 004703, Japanese Patent Publication No. 2008-45011

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

[0009] The present invention provides a method for manufacturing an electronic device as follows: [1] A method for manufacturing an electronic device comprising the steps of: preparing a structure including 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); and processing the workpiece temporarily fixed to the adhesive resin layer (C), wherein the adhesive resin layer (C) includes a thermosetting resin-containing thermo-expandable microsphere. [2] The method for manufacturing an electronic device according to [1], wherein the thermosetting resin-containing microsphere includes a shell and a volatile expansion agent within the shell, and the shell includes the thermosetting resin. [3] The method for manufacturing an electronic device according to [1] or [2], wherein the curing temperature of the thermosetting resin is equal to or greater than the foaming temperature of the thermosetting resin-containing microsphere. [4] The method for manufacturing an electronic device according to any one of [1] to [3], wherein the foaming temperature of the thermosetting resin-containing microsphere is 160°C or higher. [5] The method for manufacturing an electronic device according to any one of [1] to [4], wherein the adhesive resin layer (C) is a layer whose adhesive strength decreases by heat treatment. [6] The method for manufacturing an electronic device according to any one of [1] to [5], wherein the adhesive resin layer (C) contains one or more selected from the group consisting of (meth)acrylic adhesive resin, silicone adhesive resin, urethane adhesive resin, olefin adhesive resin, and styrene adhesive resin. [7] The method for manufacturing an electronic device according to any one of [1] to [6], 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. [8] The particle size D when the cumulative frequency is 50% in the volume-based cumulative frequency distribution curve of the thermally expandable microspheres measured by a laser diffraction scattering particle size distribution analyzer. ５０A method for manufacturing an electronic device according to any one of [1] to [7], wherein the thickness of the material is 5 μm or more and 40 μm or less. [9] A method for manufacturing an electronic device according to any one of [1] to [8], wherein the base layer (A) comprises one or more selected from the group consisting of polypropylene, polyethylene terephthalate, polyethylene naphthalate, polyamide, polyimide, and polyether ether ketone.

[10] A method for manufacturing an electronic device according to any one of [1] to [9], wherein the thickness of the adhesive resin layer (C) is 10 μm or more and 100 μm or less.

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

[10] , 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 matter) A structure 1 is fabricated by attaching the adhesive resin layer (C) of the adhesive film to a silicon wafer. Then, the structure 1 is heated at 150°C for 1 hour. Then, the structure 1 is heated at 200°C for 60 seconds. Then, 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.

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

[11] , further comprising an adhesive resin layer (B) capable of temporarily fixing at least one of an electronic component and a substrate, wherein the substrate layer (A) is located between the adhesive resin layer (B) and the adhesive resin layer (C).

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

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

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

[12] or

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

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

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

[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.

[0011] This is a schematic cross-sectional view illustrating an example of a method for manufacturing the electronic device according to this embodiment. This is a schematic cross-sectional view illustrating an example of a method for manufacturing the electronic device according to this embodiment. This is a schematic cross-sectional view illustrating an example of a structure of the adhesive film used in the method for manufacturing the electronic device according to this embodiment, together with the workpiece and support member. This is a schematic cross-sectional view illustrating an example of a structure of the adhesive film used in the method for manufacturing the electronic device according to this embodiment, together with the workpiece and support member. This is a schematic cross-sectional view illustrating an example of a structure of the adhesive film used in the method for manufacturing the electronic device according to this embodiment, together with the workpiece and support member. This is a schematic cross-sectional view illustrating an example of a structure of the adhesive film used in the method for manufacturing the electronic device according to this embodiment, together with the workpiece and support member.

[0012] In this specification, the term "(meth)acrylate" encompasses both acrylate and methacrylate. The same applies to similar terms such as "(meth)acryloyl." For each component described in this specification, one type may be used, or two or more types may be used in combination. Furthermore, unless otherwise specified, the numerical range "A to B" refers to a range between A and B. To avoid complexity, if there are multiple identical components in the same drawing, only one may be assigned a reference numeral, and none of them may be assigned a reference numeral. Drawings are for illustrative purposes only. The shapes and dimensional ratios of each component in the drawings do not necessarily correspond to actual articles.

[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.

[0014] <Method for Manufacturing an Electronic Device> The method for manufacturing an electronic device according to 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 an electronic device according to this embodiment includes a step of processing the workpiece temporarily fixed to the adhesive resin layer (C). In the method for manufacturing an electronic device according to this embodiment, the adhesive resin layer (C) includes thermally expandable microspheres containing a thermosetting resin. The method for manufacturing an electronic device according to this embodiment, having the above configuration, can reduce contamination of the workpiece.

[0015] The reason for this is not entirely clear, but the following reasons can be inferred. It is thought that the inclusion of a thermosetting resin in the heat-expandable microspheres of the adhesive film used in the manufacturing method of the electronic device of this embodiment makes it less likely for the strength of the heat-expandable microspheres to decrease even when the heating temperature is high or the heating time is long during the heating process to peel off the adhesive film. Therefore, it is thought that the expanded heat-expandable microspheres are less likely to break even when the heating temperature is high or the heating time is long during the heating process to peel off the adhesive film used in the manufacturing method of the electronic device of this embodiment. As a result, it is thought that the manufacturing method of the electronic device of this embodiment can reduce contamination of the object.

[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 of preparing a structure 100 including an adhesive film 10 and a workpiece 20 temporarily fixed to the adhesive film 10 (step X1) (2) A step of processing the workpiece 20 temporarily fixed to the adhesive film 10 (step X2)

[0018] As described above, the adhesive film 10 of this embodiment can reduce contamination of the object. Therefore, according to the method for manufacturing 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. As a result, according to the method for manufacturing 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] (Step X1) Step X1 prepares a structure 100 including 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 the step of preparing a structure 100 including 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 comprise 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, etc. 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 manufactured, for example, by the following procedure. 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 members 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 of the base material 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 on 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 object to be processed 20 onto 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. 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 object to be processed 20 during attachment, but 25°C to 80°C is preferred. There are also no particular restrictions on the pressure applied to the adhesive film 10 and the object to be processed 20 during attachment, but 0.3 MPa to 0.5 MPa 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 be, for example, the sealing of an electronic component with a sealing material. Alternatively, the processing applied to the workpiece 20 may be, for example, the dicing of an electronic component using a dicing device. Alternatively, the processing applied to the workpiece 20 may be, for example, the dicing of a ceramic capacitor using a dicing device. Alternatively, the processing applied to the workpiece 20 may be, for example, processing of a thin glass substrate, such as forming an electronic component on a thin glass substrate.

[0025] (Step X3) The manufacturing method X preferably further includes step X3 after step X2. In step X3, the adhesive force of the adhesive resin layer (C) is reduced by applying an external stimulus to peel 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, heating the structure 100 causes the thermally expandable microspheres in the adhesive resin layer (C) of the adhesive film 10 to foam, thereby reducing the adhesive strength. The method for heating the structure 100 is not particularly limited, but examples include heating methods such as electric heaters, dielectric heating, magnetic heating, heating with electromagnetic waves (near-infrared, mid-infrared, far-infrared, etc.), ovens, and hot plates.

[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 of preparing a structure 200 including an adhesive film 10 and an electronic component 21 temporarily fixed to the adhesive film 10 (step X1a) (2) A step of dicing the electronic component 21 (step 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] (Step 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 the electronic component 21 to the adhesive resin layer (C) of the adhesive film 10. Step X1a corresponds to step X1 of manufacturing method X.

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

[0034] (Step X3a) The manufacturing method Xa preferably further includes step X3a after step X2a. In step X3a, an external stimulus is applied to the adhesive film 10 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. The external stimulus applied to the adhesive film 10 is, 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. Step X3a corresponds to step X3 of the manufacturing method X.

[0035] (Step 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 picking allows the electronic components 41 to be peeled off the adhesive film 10. Known methods can be used to pick up the electronic components 41.

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

[0037] For example, after performing step X4a, any other process 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, or a wire bonding process, a sealing process, or a solder reflow process.

[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] As for the processing of the thin glass substrate 22, examples include cutting of the thin glass substrate 22, formation of an organic EL element on the thin glass substrate 22, inkjet processing, gravure printing, screen printing, spray coating, dispenser coating, air spray, electrostatic coating, roll coating, brush painting, roller brush painting, dip coating, and the like. As for the uses of the processed thin glass substrate 22, examples include cover glass for smartphones; flexible displays such as organic EL elements; water vapor and oxygen barrier layers for organic EL elements and the like; cover glass for flexible lighting and various sensors, and the like.

[0040] Hereinafter, taking the formation of an organic EL element (electronic component 23) on the thin glass substrate 22 as an example, the manufacturing method Xb will be described while referring to FIG. 3.

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

[0042] Hereinafter, each step of the manufacturing method Xb will be described while referring to FIG. 3. The adhesive film 10 used in the manufacturing method Xb further includes an intermediate layer (D) positioned between an adhesive resin layer (B), a base material layer (A), and an adhesive resin layer (C).

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

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

[0045] Next, the structure 300 can be manufactured by attaching the thin glass substrate 22 to 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 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 or more and 150 μm or less, more preferably 15 μm or more and 70 μm or less, and even more preferably 20 μm or more and 50 μm or less, from the viewpoint of improving the balance between flexibility and ease of processing.

[0046] (Step 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. An organic EL element is composed of, for example, an anode / hole injection layer / hole transport layer / light-emitting layer / hole blocking layer / electron transport layer / cathode. As a method for forming the organic EL element, for example, a thin film made of an anode material (for example, indium tin oxide: ITO, etc.) is formed to a thickness of 10 to 200 nm by a vacuum deposition method such as PVD (physical vapor deposition) or CVD (chemical vapor deposition) to produce an anode. The conditions for the vacuum deposition method are, for example, a deposition temperature of 70 to 250°C and a vacuum degree of 10 ―２ ~10 ―６ Pa, deposition rate is 0.01 to 30 nm / second.

[0047] Next, organic compound thin films comprising 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 the 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 method for forming the organic compound thin film is preferably 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 a cathode material is formed on it by vacuum deposition to a thickness of 50 to 200 nm to create a cathode. This allows for the formation of an organic EL element (electronic component 23) on the thin glass substrate 22. Furthermore, this enables the fabrication of an electronic component 42 (the thin glass substrate 22 on which the electronic component 23 is formed). Note that step X2b corresponds to step X2 of manufacturing method X.

[0049] (Step 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. Step X3b corresponds to step X3 of the manufacturing method X.

[0050] <Applications of the Method for Manufacturing Electronic Devices> The method for manufacturing electronic devices of this embodiment can reduce contamination of the object, and therefore its applications are not particularly limited, and it can be used in the manufacturing of electronic devices that include 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. Here, in this specification, "workpiece" means an object that is processed while it is temporarily fixed to another object by an adhesive film. Also, in this specification, a support member means a member that temporarily fixes the workpiece with an adhesive film. The workpiece includes, for example, one or more selected from the group consisting of electronic components and a substrate.

[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 a 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 electronic components and substrates. 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 an electronic device including a fan-out type package. In this case, the electronic device of this embodiment includes a semiconductor package. The semiconductor package includes, for example, a fan-out type package. The adhesive film of this embodiment may also 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 step of a thin glass substrate. Note that the substrate processing tape is not limited to thin glass substrates and may be used in the processing steps of 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] <Structure 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 upon heating. The thermally expandable microspheres of this embodiment include a thermosetting resin. The thermally expandable microspheres may also include substances other than thermosetting resins. For example, the thermally expandable microspheres may include thermoplastic resins, volatile expanding agents, curing agents, and other additives.

[0062] A thermally expandable microsphere preferably comprises a shell and a volatile expanding agent within the shell. In this case, the shell contains a thermosetting resin. More preferably, the thermally expandable microsphere has a structure in which the volatile expanding agent is contained 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 selected from the group consisting of bisphenol A type epoxy resins, bisphenol F type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, dicyclopentadiene type epoxy resins, and glycidylamine type epoxy resins. The phenolic resin includes, for example, one or more selected from the group consisting of novolac type phenolic resins, resol type phenolic resins, and benzyl ether type phenolic resins.

[0064] 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 optionally contain a catalyst used to cure the thermosetting resin.

[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. The volatile expanding agent includes, for example, one or more 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 being able to improve the foaming rate of the thermally expandable microspheres, the volatile expanding 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 lower, 275°C or lower, 250°C or lower, 225°C or lower, or 200°C or lower. The foaming temperature of the thermally expandable microspheres is preferably 160°C or higher and 300°C or lower, more preferably 165°C or higher and 275°C or lower, even more preferably 170°C or higher and 250°C or lower, even more preferably 175°C or higher and 225°C or lower, and even more preferably 180°C or higher and 200°C or lower, 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 layer (A)] The base layer (A) is a layer provided for the purpose of improving the handling properties, mechanical properties, heat resistance, and other properties 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 resins constituting the resin film include, for example, thermoplastic resins. The resins constituting the resin film include, for example, one or more selected from the group consisting of polyolefins, polyesters, polyamides, poly(meth)acrylates, polyvinyl chloride, polyvinylidene chloride, 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). Polyesters include, for example, one or more selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Polyamides include, for example, one or more selected from the group consisting of nylon-6, nylon-66, and polymetaxylene adipamide. Aromatic polyether ketones include, for example, one or more selected from the group consisting of polyether ketone (PEK), polyether ether ketone (PEEK), polyether ketone ketone (PEKK), polyether ether ketone ketone (PEEKK), and polyether ketone 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. The resin film used to form the base layer (A) is, for example, a stretched film, and is preferably a film stretched in one or two axes from the viewpoint of improving the mechanical strength of the base layer (A).

[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 a layer located on one side (first surface A1 side) of the base 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. The radiation-crosslinked adhesive resin layer (B) becomes easier to peel off the adhesive film from the object because its adhesive strength decreases due to crosslinking upon irradiation with radiation. 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) 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, and preferably includes 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 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 content 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. The substrate layer (A) and the adhesive resin layer (B) may be formed by co-extrusion molding, or by laminating (layering) a film-like substrate 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). Preferably, the adhesive resin layer (C) is 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 a temperature of 160°C or higher 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 becomes less than 0.5 N / 25 mm. (Method for Evaluating Decrease in Adhesion 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. Next, 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 at a temperature of 160°C or higher is appropriately set 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 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 an alkyl (meth)acrylate having an alkyl group having about 1 to 12 carbon atoms, more preferably an alkyl (meth)acrylate having an alkyl group having 1 to 8 carbon atoms, and even more preferably one or more selected from the group consisting of 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. Preferably, the monomer (c2) includes one or more selected from the group consisting of (meth)acrylic acid, 2-hydroxyethyl (meth)acrylate, 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. The organic peroxide includes, 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-butylperoxy-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 an adhesive resin (C1) and preferably a crosslinking agent (C2) having two or more crosslinkable functional groups per molecule. The crosslinking agent (C2) is used to react with the functional groups of the adhesive resin (C1) to adjust the adhesive strength and cohesive strength 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, trimethylolpropane toluene diisocyanate 3 adduct, polyisocyanate, diphenylmethane diisocyanate, and tolylene diisocyanate. Aziridine crosslinking agents include, 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. Tetrafunctional epoxy crosslinking agents include, 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 crosslinking agent (C2) content 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, it may be included in excess as needed, such as when new functional groups are generated in the crosslinking reaction or when the crosslinking reaction is slow. From the viewpoint of 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 adhesive resin (C1) content 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 adhesive resin (C1) content 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 resins include, for example, rosin derivatives that have undergone treatment such as esterification. Terpene resins include, 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 target object and improving adhesion to the target 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 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 of adhesiveness and heat 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 handlingability of the adhesive film 10. The thickness of the adhesive resin layer (C) is preferably 10 μm or more and 100 μm or less, more preferably 15 μm or more and 75 μm or less, even more preferably 20 μm or more and 50 μm or less, and even more preferably 25 μm or more and 40 μm or less, from the viewpoint of improving the balance of adhesiveness, heat release properties, and handling properties.

[0115] The adhesive resin layer (C) can be formed, for example, by applying an adhesive coating solution onto the substrate layer (A), or by transferring the adhesive resin layer (C) formed on the separator onto the substrate layer (A). Examples of methods for applying the adhesive coating solution 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.

[0116] There are no particular restrictions on the drying conditions for the applied adhesive, but for example, it may be dried at 80 to 170°C for 15 seconds to 5 minutes. In order to sufficiently promote the crosslinking reaction between the crosslinking agent and the adhesive, the adhesive coating solution may be heated at 40 to 80°C for about 5 to 300 hours after the drying is complete.

[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] [Intermediate 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, as a dicing tape, the intermediate layer (D) more preferably contains 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, ethylene resins include, for example, one or more selected from the group consisting of high-density polyethylene resins (HDPE), medium-density polyethylene resins (MDPE), low-density polyethylene resins (LDPE), ultra-low-density polyethylene resins (ULDPE), and linear low-density polyethylene resins (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 copolymer, ethylene vinyl propionate copolymer, ethylene vinyl butyrate copolymer, and ethylene vinyl stearate copolymer.

[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. From the viewpoint of availability, 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. 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 contain additives such as plasticizers as other components. The intermediate layer (D) may be a single layer or a multilayer layer.

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

[0127] The number of foreign objects observed in the adhesive film of this embodiment according to the following (method for observing foreign objects) will be explained.

[0128] The number of foreign objects observed according to the method for observing foreign objects described below 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, but it may be 0 or more, 1 or more, or 2 or more.

[0129] (Method for observing foreign matter) 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. 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. Here, the method for observing foreign matter can be more specifically the method described in the examples.

[0130] The evaluation values ​​of particles measured according to the following (method for evaluating particles) for the adhesive film of this embodiment will be described.

[0131] 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. The lower limit of the particle evaluation value is not particularly limited, but may be, for example, 0 or more, 10 or more, or 100 or more.

[0132] (Method for evaluating particles) A ​​silicon wafer is heated at 150°C for 1 hour. Next, the silicon wafer is left to cool in a cleanroom at 23°C for 30 minutes. Next, the silicon wafer is heated at 200°C for 60 seconds. 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 P2. Next, a structure 2 is fabricated by attaching an adhesive resin layer (C) of an adhesive film to the silicon wafer. Next, structure 2 is heated at 150°C for 1 hour. Next, structure 2 is left to cool in a cleanroom at 23°C for 30 minutes. Next, structure 2 is heated at 200°C for 60 seconds. Next, the adhesive film is peeled off the silicon wafer. Next, 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.

[0133] <Structure of the Adhesive Film> Several examples of the structure of the adhesive film 10 of 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 as shown in Figures 4 to 7 below, for example.

[0134] The adhesive film 10 in Figure 4 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 by the adhesive resin layer (C). The adhesive film 10 in Figure 4 may be temporarily fixed to the support member 30 by being pressed against it by a fixing ring or the like, or by being attracted to the support member 30 by 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.

[0135] 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.

[0136] 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).

[0137] In Figure 5, the adhesive film 10 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). The adhesive film 10 in Figure 5 temporarily fixes the workpiece 20 with the adhesive resin layer (C). The adhesive film 10 in Figure 5 is also temporarily fixed to the support member 30 with the adhesive resin layer (B).

[0138] The adhesive film 10 in Figure 5 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 (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 further include an intermediate layer (D) in both the space between the base layer (A) and the adhesive resin layer (B), and between the base layer (A) and the adhesive resin layer (C), if necessary. 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).

[0139] 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).

[0140] 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 layer (A). In this case, the adhesive resin layer (C) on the first surface A1 side of the base 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 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. The adhesive film 10 in Figure 7 temporarily fixes the workpiece 20 by the adhesive resin layer (CA2). The adhesive film 10 in Figure 7 is also temporarily fixed to the support member 30 by the adhesive resin layer (CA1).

[0141] The adhesive film 10 in Figure 7 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 (CA1), and between the base layer (A) and the adhesive resin layer (CA2). Note that the intermediate layer (D) is not shown in Figure 7. Furthermore, the adhesive film 10 in Figure 7 may also include an intermediate layer (D) as needed, both between the base layer (A) and the adhesive resin layer (CA1), and between the base layer (A) and the adhesive resin layer (CA2). In this case, the intermediate layer (D) located between the base 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 layer (A) and the adhesive resin layer (CA2).

[0142] <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). Alternatively, the adhesive film 10 of this embodiment may be formed by laminating (layering) 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 base layer (A) and the adhesive resin layer (C) in this order.

[0143] One method for applying an adhesive resin layer (C) onto a substrate layer (A) is to apply an adhesive coating solution capable of forming an adhesive resin layer (C). Examples of methods for applying the adhesive coating solution 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 solution, 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 adhesive coating 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 completed.

[0144] 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). Alternatively, 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.

[0145] 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 that order; by co-extruding an adhesive resin layer (B), a base layer (A), an intermediate layer (D), and an adhesive resin layer (C) in that 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.

[0146] 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). Alternatively, 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. Furthermore, the adhesive film 10 of this embodiment may be formed by co-extrusion molding in the order of adhesive resin layer (CA1), base material layer (A), and adhesive resin layer (CA2).

[0147] Although embodiments of the present invention have been described above, these are merely examples, and various other configurations can be adopted. Furthermore, the present invention is not limited to the embodiments described above, and modifications, improvements, etc., that do not impair the effects of the present invention are included in the present invention.

[0148] 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.

[0149] The details of the materials used to produce the adhesive film are as follows:

[0150] <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. Emulsion polymerization was carried out at 70-72°C for 8 hours under stirring to obtain an acrylic resin emulsion. This was neutralized with ammonia water (pH = 7.0) to obtain adhesive resin solution SB1 with a solid content concentration of 42.5%.

[0151] <Adhesive Resin Solution SB2> In 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 adhesive resin solution SB2 with a solid content concentration of 56.5%.

[0152] <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.

[0153] <Adhesive Resin Solution SC1> In a mixed solvent containing ethyl acetate and toluene, 0.536 parts by mass of t-butylperoxy-2-ethylhexanoate (manufactured by Nippon Oil & Fats Co., Ltd., trade name: Perbutyl O (registered trademark)) as a polymerization initiator, 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. 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.

[0154] <Adhesive Coating Solution 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., product 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.

[0155] <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., product 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., product 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., product 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 the thermosetting resin-containing thermally expandable microspheres (Advancel 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.

[0156] <Adhesive Coating Solution 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., product 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., product 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., product 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 the thermosetting resin-containing thermally expandable microspheres (Advancel 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.

[0157] <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., product 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., product 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., product 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 as measured by a laser diffraction scattering particle size distribution analyzer. ５０ The size was 17.6 μm.

[0158] [Example 1] A polyethylene terephthalate (PET) film (38 μm thick), which is a base layer (A), was covered with a 10 μm thick adhesive resin layer (B) formed by drying adhesive coating liquid B1. Next, a 20 μm thick intermediate layer (D) formed by drying adhesive coating liquid C1 was applied to the surface of the PET film opposite to the adhesive resin layer (B), and a 30 μm thick heat-peelable adhesive resin layer (C) formed by drying adhesive coating liquid C2 was applied on top of that to obtain an adhesive film.

[0159] [Example 2] A polyethylene terephthalate (PET) film (38 μm thick), which is the base layer (A), was covered with a 10 μm thick adhesive resin layer (B) formed by drying adhesive coating liquid B1. Next, a 20 μm thick intermediate layer (D) formed by drying adhesive coating liquid C1 was applied to the surface of the PET film opposite to the adhesive resin layer (B), and a 30 μm thick heat-peelable adhesive resin layer (C) formed by drying adhesive coating liquid C3 was applied on top of that to obtain an adhesive film.

[0160] [Comparative Example 1] A polyethylene terephthalate (PET) film (38 μm thick), which is a base layer (A), was provided with a 10 μm thick adhesive resin layer (B) formed by drying adhesive coating liquid B1. Next, a 20 μm thick intermediate layer (D) formed by drying adhesive coating liquid C1 was provided on the surface of the PET film opposite to the adhesive resin layer (B), and a 30 μm thick heat-peelable adhesive resin layer (C) formed by drying adhesive coating liquid C4 was provided on top of that to obtain an adhesive film.

[0161] (Examples 1-2, Comparative Example 1) The physical properties of the adhesive films in each example were measured by the following method. The measurement results are shown in Table 1.

[0162] <Method for Evaluating Adhesive Residue> The following procedure was performed using the adhesive film for each example. Structure 1 was fabricated by attaching the adhesive resin layer (C) of the 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. Next, structure 1 was heated in a hot plate with the silicon wafer side of structure 1 in contact with the hot plate at 200°C for 60 seconds. 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 procedures were performed in a Class 10,000 cleanroom. This evaluation was performed with a sample size n=3. The average value for each sample was taken as the number of foreign matter. 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.

[0163] <Method for Evaluating Particles> The following operations were performed using the adhesive film for each example. First, particle measurements were taken without attaching the adhesive film to the silicon wafer. Specifically, the 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 left to cool in a clean room at 23°C for 30 minutes. Next, the silicon wafer was heated at 200°C for 60 seconds. Then, using a wafer surface inspection device (product name: WM-7S, manufactured by Takano Corporation), the particles on the surface of the silicon wafer were counted under the conditions (settings) below. The total number of particles at this time was defined as the measured value P2. Next, structure 2 was fabricated by attaching the adhesive resin layer (C) of the adhesive film to the 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. Then, structure 2 was allowed to cool in a cleanroom 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. Then, using a wafer surface inspection device (product name: WM-7S, manufactured by Takano Corporation), the particles on the surface of the silicon wafer were counted 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 defined as the value for each sample. All of the above operations were performed in a Class 10,000 cleanroom. This evaluation was performed with a sample size n = 3. The average value for each sample was defined as the particle evaluation value. 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.

[0164] (Settings) Measurement Mode: High-Resolution Measurement Type: Normal Measurement Transfer: None Map ORG: Center

[0165]

[0166] This application claims priority based on Japanese Patent Application No. 2024-168683, filed on 27 September 2024, and incorporates all of its disclosures herein.

[0167] 10 Adhesive film 20 Object to be processed 21 Electronic component 22 Thin glass substrate 23 Electronic component 30 Support member 31 Support substrate 40 Object to be processed after processing 41 Electronic component 42 Electronic component 100 Structure 200 Structure 300 Structure A Base material layer A1 First surface A2 Second surface B Adhesive resin layer C Adhesive resin layer CA1 Adhesive resin layer CA2 Adhesive resin layer D Intermediate layer

Claims

1. A method for manufacturing an electronic device, comprising the steps of: preparing a structure including 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); and processing the workpiece temporarily fixed to the adhesive resin layer (C), wherein the adhesive resin layer (C) includes thermally expandable microspheres containing a thermosetting resin.

2. The method for manufacturing an electronic device according to claim 1, wherein the thermally expandable microsphere comprises a shell and a volatile expanding agent within the shell, and the shell comprises the thermosetting resin.

3. The method for manufacturing an electronic device according to claim 1 or 2, wherein the curing temperature of the thermosetting resin is equal to or greater than the foaming temperature of the thermally expandable microspheres.

4. The method for manufacturing an electronic device according to any one of claims 1 to 3, wherein the foaming temperature of the thermally expandable microspheres is 160°C or higher.

5. The method for manufacturing an electronic device according to any one of claims 1 to 4, wherein the adhesive resin layer (C) is a layer whose adhesive strength decreases when heated.

6. The method for manufacturing an electronic device according to any one of claims 1 to 5, 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.

7. A method for manufacturing an electronic device according to any one of claims 1 to 6, 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.

8. 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 size D at which the cumulative frequency reaches 50% ５０ A method for manufacturing an electronic device according to any one of claims 1 to 7, wherein the thickness is 5 μm or more and 40 μm or less.

9. The method for manufacturing an electronic device according to any one of claims 1 to 8, wherein the substrate layer (A) comprises one or more selected from the group consisting of polypropylene, polyethylene terephthalate, polyethylene naphthalate, polyamide, polyimide, and polyetheretherketone.

10. The method for manufacturing an electronic device according to any one of claims 1 to 9, wherein the thickness of the adhesive resin layer (C) is 10 μm or more and 100 μm or less.

11. A method for manufacturing an electronic device according to any one of claims 1 to 10, wherein the number of foreign objects observed on 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 made 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 the silicon wafer. Next, the number of foreign objects 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.

12. A method for manufacturing an electronic device according to any one of claims 1 to 11, further comprising an adhesive resin layer (B) capable of temporarily fixing at least one of an electronic component and a substrate, wherein the base layer (A) is located between the adhesive resin layer (B) and the adhesive resin layer (C).

13. The method for manufacturing an electronic device according to claim 12, wherein the thickness of the adhesive resin layer (B) is 1 μm or more and 40 μm or less.

14. The method for manufacturing an electronic device according to claim 12 or 13, 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).

15. The method for manufacturing an electronic device according to claim 14, wherein the thickness of the intermediate layer (D) is 5 μm or more and 100 μm or less.

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