Manufacturing method of electronic device

Abstract

A method for manufacturing an electronic device includes the steps of: preparing a structure (100) including an adhesive film (10) having a base layer (A), an adhesive resin layer (B), and an adhesive resin layer (C); an object to be processed (20) temporarily fixed to the adhesive resin layer (B); and a support member (30) temporarily fixed to the adhesive resin layer (C); and processing the object to be processed (20) temporarily fixed to the adhesive resin layer (B), wherein the base layer (A) is located between the adhesive resin layer (B) and the adhesive resin layer (C), the adhesive resin layer (C) contains heat-expandable microspheres, and the heat-expandable microspheres have a sphericity R of 0.93 or more as calculated by a predetermined formula.

Description

[Technical Field]

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

[0002] Techniques for using adhesive films in the manufacturing process of electronic devices include those described in Patent Documents 1 to 3, for example.

[0003] Patent Document 1 aims to provide a dicing tape and DDAF that are suitable for increasing the separation distance while suppressing lifting of DAF-attached semiconductor chips from the dicing tape after cleavage in an expanding process using a dicing die bond film (DDAF) to obtain semiconductor chips with DAFs, and that are also suitable for achieving good pick-up properties in a pick-up process. The dicing tape has a laminated structure including a substrate and a pressure-sensitive adhesive layer, and the ratio of the second tensile stress generated at a strain value of 20% in a tensile test conducted on a dicing tape specimen with a width of 20 mm under conditions of an initial chuck distance of 100 mm, 23°C, and a tensile speed of 10 mm / min to the first tensile stress generated at a strain value of 20% in a tensile test conducted on a dicing tape specimen with a width of 20 mm under 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 describes a heat-resistant adhesive sheet for semiconductor device manufacturing that is used by adhering when resin-encapsulating a substrateless semiconductor chip, with the aim of solving the problem of the chip not being held in place due to pressure during resin encapsulation and shifting from its designated position, or the problem of the package being damaged when the heat-resistant adhesive sheet for semiconductor device manufacturing is peeled off due to the hardening of the encapsulant or heat causing it to become strongly adhesive to the chip surface, and is characterized in that the heat-resistant adhesive sheet has a base layer and an adhesive layer, and the adhesive layer has an adhesive strength to SUS304 of 0.5 N / 20 mm or more after lamination, and hardens due to stimuli received up to the time the resin encapsulation process is completed, so that the peel strength to 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 ultra-thin glass substrate, which allows organic EL elements to be formed efficiently by vacuum deposition without causing the ultra-thin glass substrate to "crack" or "chick" during the manufacturing process, and which allows the organic EL panel to be recovered after the manufacturing process without damaging the ultra-thin glass substrate, eliminating the need for a step of cleaning the back surface of the ultra-thin glass substrate. The method involves forming organic electroluminescent elements on an ultra-thin glass substrate by vacuum deposition, and temporarily fixing the ultra-thin glass substrate to a support plate via a double-sided adhesive tape having, on at least one side of a base layer, a heat-peelable adhesive layer containing heat-expandable microspheres that begin to expand and / or foam at a temperature higher than the vacuum deposition temperature, and then forming electrodes on the ultra-thin glass substrate.

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

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2019-16634 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-134811 [Patent Document 3] International Publication No. 2010 / 004703 [Patent Document 4] Japanese Patent Application Laid-Open No. 2008-45011 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention provides a method for manufacturing an electronic device with improved object retention. [Means for solving the problem]

[0009] According to the present invention, there is provided a method for manufacturing an electronic device, as described below. [1] A step of preparing a structure including an adhesive film having a base layer (A), an adhesive resin layer (B), and an adhesive resin layer (C), an object to be processed temporarily fixed to the adhesive resin layer (B), and a support member temporarily fixed to the adhesive resin layer (C); and processing the object temporarily fixed to the adhesive resin layer (B), the base material layer (A) is located between the adhesive resin layer (B) and the adhesive resin layer (C), the adhesive resin layer (C) contains heat-expandable microspheres, The method for producing an electronic device, wherein the heat-expandable microspheres have a sphericity R of 0.93 or more as calculated by the following formula (1):

number

[10] The method for producing an electronic device according to any one of [1] to [9] above, wherein the adhesive resin layer (B) has a thickness of 1 μm or more and 40 μm or less.

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

[10] above, further comprising providing an intermediate layer (D) at least either between the base material layer (A) and the adhesive resin layer (B) or between the base material layer (A) and the adhesive resin layer (C).

[12] The method for producing an electronic device according to

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

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

[12] above, wherein the electronic device includes a semiconductor package.

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

[13] , wherein the semiconductor package includes a fan-out type package. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a method for manufacturing an electronic device with improved holding power for an object. [Brief explanation of the drawings]

[0011] [Figure 1] 1A to 1C are cross-sectional views schematically illustrating an example of a method for manufacturing an electronic device according to an embodiment of the present invention. [Figure 2] 1A to 1C are cross-sectional views schematically illustrating an example of a method for manufacturing an electronic device according to an embodiment of the present invention. [Figure 3] 1A to 1C are cross-sectional views schematically illustrating an example of a method for manufacturing an electronic device according to an embodiment of the present invention. [Figure 4] 1 is a cross-sectional view schematically showing an example of the structure of an adhesive film used in the method for manufacturing an electronic device of the present embodiment, together with an object to be processed and a support member. [Figure 5] 1 is a cross-sectional view schematically showing an example of the structure of an adhesive film used in the method for manufacturing an electronic device of the present embodiment, together with an object to be processed and a support member. DETAILED DESCRIPTION OF THE INVENTION

[0012] In this specification, the term "(meth)acrylate" represents a concept that encompasses both acrylate and methacrylate. The same applies to similar terms such as "(meth)acryloyl." Each component described in this specification may be used alone or in combination of two or more. Furthermore, the expression "A to B" regarding a numerical range means A or more and B or less unless otherwise specified. To avoid complexity, when there are multiple identical components in the same drawing, only one of them may be labeled with a symbol, and not all of them. The drawings are for illustrative purposes only, and the shapes and dimensional ratios of the components in the drawings do not necessarily correspond to the actual products.

[0013] In the past, adhesive films sometimes contained heat-expandable microspheres in the adhesive resin layer that comes into contact with the object. The inventors' investigations revealed that heat-expandable microspheres contained aggregates of heat-expandable microspheres and coarse particles such as irregularly shaped particles derived from heat-expandable microspheres that did not become spherical during the manufacturing process. They also discovered that the coarse particles caused unevenness on the surface of the adhesive film (surface of the adhesive resin layer). When the surface of an adhesive film becomes uneven, an object temporarily fixed by the adhesive film becomes more likely to come off the adhesive film. In other words, when the surface of an adhesive film becomes uneven, the adhesive film's ability to hold the object decreases. This can result in manufacturing defects in the manufacturing process of electronic devices using the adhesive film. Further investigation by the present inventors revealed that the content of coarse particles in heat-expandable microspheres is small relative to the total content of heat-expandable microspheres, and that it is difficult to distinguish, from the viewpoint of particle size distribution, between heat-expandable microspheres with a relatively low content of coarse particles (heat-expandable microspheres that can produce adhesive films with high object-holding power) and heat-expandable microspheres with a relatively high content of coarse particles (heat-expandable microspheres that can produce adhesive films with low object-holding power).

[0014] <Electronic Device Manufacturing Method> The method for manufacturing an electronic device of this embodiment includes the step of preparing a structure including an adhesive film having a base layer (A), an adhesive resin layer (B), and an adhesive resin layer (C), an object to be processed temporarily fixed to the adhesive resin layer (B), and a support member temporarily fixed to the adhesive resin layer (C). The method for manufacturing an electronic device of this embodiment includes the step of processing the object to be processed temporarily fixed to the adhesive resin layer (B). In the method for manufacturing an electronic device of this embodiment, the base layer (A) is located between the adhesive resin layer (B) and the adhesive resin layer (C). In the method for manufacturing an electronic device of this embodiment, the adhesive resin layer (C) contains heat-expandable microspheres. In the method for manufacturing an electronic device of this embodiment, the heat-expandable microspheres have a sphericity R of 0.93 or more, calculated by the following formula (1):

number

[0015] The reason for this is not entirely clear, but the following reasons are presumed. It is believed that the coarse particles contained in the heat-expandable microspheres have shapes that deviate more from a perfect sphere than normal heat-expandable microspheres. Here, the sphericity R (hereinafter also referred to as sphericity R), calculated by formula (1) and used to evaluate the heat-expandable microspheres in the PSA film in this embodiment, is a parameter that evaluates both the particle size (circle-equivalent diameter) and the particle shape (degree of circularity). Therefore, it is believed that the amount of coarse particles, which was difficult to evaluate based on the particle size distribution, can now be evaluated using sphericity R. The heat-expandable microspheres in the adhesive film used in the method for producing an electronic device of this embodiment have a sphericity R of at least a predetermined value, which reduces the surface irregularities of the adhesive film caused by coarse particles, thereby improving the adhesive film's ability to hold an object. As a result, the method for producing an electronic device of this embodiment is believed to improve the adhesive film's ability to hold an object.

[0016] Hereinafter, a method for manufacturing an electronic device (manufacturing method Y) in which the adhesive resin layer (C) of the adhesive film 10 of this embodiment, which will be described later, is in contact with the support member 30 will be described.

[0017] [Manufacturing method Y] The manufacturing method Y includes, for example, the following two steps. (1) A step of preparing a structure 100 including an adhesive film 10 and an object 20 temporarily fixed to the adhesive film 10 (step Y1) (2) A step of processing the object 20 temporarily fixed to the adhesive film 10 (step Y2)

[0018] As described above, the adhesive film 10 of this embodiment has improved holding power for an object. Therefore, according to the manufacturing method (manufacturing method Y) for an electronic device using the adhesive film 10 of this embodiment, the holding power for an object can be improved. Specifically, according to manufacturing method Y, it is possible to reduce peeling of the adhesive film 10 from the support member 30 during the manufacturing process. This can improve the yield of electronic devices.

[0019] Each step of the manufacturing method Y will be described below with reference to FIG. The adhesive film 10 used in production method Y further comprises an adhesive resin layer (B) on the first surface A1 side of the base material layer (A) in addition to the base material layer (A) and the adhesive resin layer (C). That is, the adhesive film 10 used in production method Y comprises the base material layer (A), the adhesive resin layer (B), and the adhesive resin layer (C). In addition, in the adhesive film 10 used in production method Y, the base material layer (A) is located between the adhesive resin layer (B) and the adhesive resin layer (C).

[0020] (Process Y1) In step Y1, a structure 100 is prepared, which includes an adhesive film 10 and an object to be processed 20 temporarily fixed to the adhesive resin layer (B) of the adhesive film 10. The structure 100 is also temporarily fixed to a support member 30 by the adhesive resin layer (C) of the adhesive film 10. In other words, process Y1 includes a step of preparing a structure 100 including an adhesive film 10, an object to be processed 20 temporarily fixed to the adhesive resin layer (B) of the adhesive film 10, and a support member 30 temporarily fixed to the adhesive resin layer (C) of the adhesive film 10. In addition, the temporary fixation between the adhesive resin layer (B) of the adhesive film 10 and the object to be processed 20 and the temporary fixation between the adhesive resin layer (C) of the adhesive film 10 and the support member 30 may be performed simultaneously, or one temporary fixation may be performed after the other temporary fixation.

[0021] Such a structure 100 can be fabricated, for example, by the following procedure. First, the adhesive film 10 is attached to the support member 30 so that the adhesive resin layer (C) faces the support member 30. A protective film called a separator may be attached to the adhesive resin layer (C). In this case, the protective film is peeled off, and the exposed surface of the adhesive resin layer (C) is attached to the surface of the support member 30.

[0022] Next, the object 20 is attached onto the adhesive resin layer (B) of the adhesive film 10 attached onto the support member 30, whereby the structure 100 can be produced.

[0023] (Process Y2) In step Y2, the object 20 temporarily fixed to the adhesive film 10 is processed. There are no particular limitations on the type of processing performed on the object 20. In Fig. 1, the object 20 is an object 40 after processing. The processing performed on the workpiece 20 may be, for example, sealing of electronic components with a sealing material. The processing performed on the workpiece 20 may also be, for example, dicing of electronic components with a dicing device. The processing performed on the workpiece 20 may also be, for example, processing of a thin glass substrate, such as forming electronic components on the thin glass substrate.

[0024] (Process Y3) Preferably, production method Y further includes step Y3 after step Y2. In step Y3, an external stimulus is applied to reduce the adhesive strength of the adhesive resin layer (C), and the structure 100 is peeled off from the support member 30.

[0025] For example, after processing the object 20, the structure 100 is heated at a temperature of 160°C or higher to reduce the adhesive strength of the adhesive resin layer (C), thereby enabling the support member 30 to be separated from the structure 100. Specifically, by heating the structure 100, the heat-expandable microspheres in the adhesive resin layer (C) of the adhesive film 10 are expanded, reducing the adhesive strength.

[0026] It should be noted that the manufacturing method Y may further include steps other than steps Y1 to Y3 as necessary.

[0027] Next, manufacturing method Y will be described using a specific example (manufacturing method Ya). Manufacturing method Ya is manufacturing method Y in which the processing performed on object 20 is sealing of electronic components 24 with sealing material 50.

[0028] [Manufacturing method Ya] The manufacturing method Ya includes, for example, the following two steps. (1) A step of preparing a structure 400 including an adhesive film 10 and an electronic component 24 temporarily fixed to the adhesive film 10 (step Y1a) (2) Step Y2a: Encapsulating the Electronic Components 24 with the Sealing Material 50

[0029] Each step of the manufacturing method Ya will be described below with reference to FIGS.

[0030] (Process Y1a) In step Y1a, a structure 400 is prepared, which includes an adhesive film 10, an electronic component 24 temporarily fixed to an adhesive resin layer (B), and a support substrate 31 temporarily fixed to an adhesive resin layer (C). The structure 400 can be produced, for example, by attaching the electronic component 24 onto the adhesive resin layer (B) of the adhesive film 10. The step Y1a corresponds to the step Y1 of the manufacturing method Y.

[0031] (Process Y2a) In step Y2a, the electronic component 24 temporarily fixed to the adhesive film 10 is sealed with a sealing material 50. For example, the electronic component 24 can be sealed by curing the sealing material 50 at a temperature of 150° C. or less while the electronic component 24 is covered with the sealing material 50. The step Y2a corresponds to the step Y2 of the manufacturing method Y.

[0032] The sealing material 50 is not particularly limited, but may be, for example, an epoxy resin-based sealing material using epoxy resin. The form of the sealing material 50 is not particularly limited, but may be, for example, granular, sheet, or liquid. In particular, the sealing material 50 is preferably a liquid epoxy resin-based sealing material from the viewpoint of improving the affinity between the adhesive film 10 and the sealing material 50 and reducing uneven sealing of the electronic component 24 . Examples of such epoxy resin-based sealing materials include the T693 / R4000 series, T693 / R1000 series, and T693 / R5000 series manufactured by Nagase ChemteX Corporation.

[0033] Examples of the sealing method include transfer molding, injection molding, compression molding, and cast molding.

[0034] (Process Y3a) The production method Ya preferably further comprises a step Y3a after the step Y2a. In the step Y3a, the adhesive strength of the adhesive resin layer (C) is reduced by applying an external stimulus, and the support substrate 31 is peeled off from the structure 400. The support substrate 31 can be separated from the adhesive film 10, for example, by heating the support substrate 31 to a temperature of 160° C. or higher after sealing the electronic components 24, thereby reducing the adhesive strength of the adhesive resin layer (C).

[0035] (Process Y4a) Preferably, the manufacturing method Ya further comprises a step Y4a after the step Y3a. In step Y4a, the adhesive film 10 is peeled off from the electronic component 24 sealed with the sealing material 50, and the electronic device 500 is obtained. Methods for peeling the adhesive film 10 from the electronic component 24 sealed with the sealing material 50 include, for example, a mechanical peeling method, a method of reducing the adhesive strength of the surface of the adhesive film 10 before peeling, etc.

[0036] (Process Y5a) The manufacturing method Ya preferably further comprises a step Y5a between the step Y1a and the step Y2a. In step Y5a, the structure 400 obtained in step Y1a is heated. This improves the adhesive strength of the adhesive resin layer (B) to the electronic components 24 in the adhesive film 10. As a result, in step Y2a for sealing, when the electronic components 24 are sealed with the sealing material 50, it is possible to reduce displacement of the electronic components 24 due to pressure caused by the flow of the sealing material 50 or outgassing caused by moisture.

[0037] In step Y5a, the upper limit of the temperature when heating the structure 400 is not particularly limited as long as it is a temperature that can improve the adhesive strength of the adhesive resin layer (B) to the electronic component 24, but is preferably less than 160°C, more preferably 155°C or less, and even more preferably 150°C or less. This can reduce the sudden generation of outgassing derived from moisture contained in the adhesive film 10. As a result, in steps Y5a and Y2a, it is possible to further reduce displacement of the electronic component 24 due to outgassing derived from moisture. Furthermore, when the temperature at which the structure 400 is heated is less than or equal to the above upper limit, the thermal expansion of the heat-expandable microspheres in the adhesive resin layer (C) is reduced, thereby reducing the decrease in the adhesive strength of the adhesive film 10 to the support substrate 31. As a result, peeling of the adhesive film 10 from the support substrate 31 can be reduced in the step Y2a of sealing the electronic component 24.

[0038] In step Y5a, the lower limit of the temperature when heating the structure 400 is not particularly limited as long as it is a temperature that can improve the adhesive strength of the adhesive resin layer (B) to the electronic component 24, but is preferably 70°C or higher, more preferably 80°C or higher, even more preferably 90°C or higher, and even more preferably 100°C or higher. This shortens the heating time in step Y5a. As a result, the manufacturing time of the electronic device 600 can be shortened, and the productivity of the electronic device 600 can be improved.

[0039] The heating time for the structure 400 is not particularly limited as long as it is a heating time that can improve the adhesive strength of the adhesive resin layer (B) to the electronic component 24, but is, for example, 1 minute or more and 120 minutes or less, preferably 5 minutes or more and 80 minutes or less. The method for heating the structure 400 is not particularly limited, but examples thereof include heat treatment methods using an oven, a dryer, a heating roll, a drying furnace, and the like.

[0040] Whether or not the adhesive strength of the adhesive resin layer (B) to the electronic component 24 has improved can be determined, for example, by the shear strength between the electronic component 24 and the adhesive film 10.

[0041] (Process Y6a) Preferably, the manufacturing method Ya further comprises a step Y6a after the step Y4a. In step Y6a, a wiring layer 510 and bumps 520 are formed on the exposed surface of the obtained electronic device 500.

[0042] The wiring layer 510 includes pads (not shown) that are external connection terminals formed on the outermost surface, and wiring (not shown) that electrically connects the pads to the electronic components 24. The wiring layer 510 can be formed by a conventionally known method and may have a multi-layer structure.

[0043] Then, bumps 520 are formed on the pads of the wiring layer 510, thereby fabricating the electronic device 500. Examples of the bumps 520 include solder bumps and gold bumps. Solder bumps can be formed, for example, by placing solder balls on pads that serve as external connection terminals of the wiring layer 510 and heating them to melt the solder (reflow). Gold bumps can be formed by methods such as ball bonding, plating, and Au ball transfer.

[0044] (Process Y7a) Preferably, the manufacturing method Ya further comprises a step Y7a after the step Y6a. In step Y7a, the electronic device 500 is diced to produce a plurality of electronic devices 600. The electronic device 500 can be diced using a known method.

[0045] <Applications of the manufacturing method for electronic devices> The method for manufacturing an electronic device according to the present embodiment can improve the holding force of an object, and therefore its application is not particularly limited, and it can be used in manufacturing methods for electronic devices that include a step of temporarily fixing various objects. Here, in this specification, the 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 an object to be processed and a support member. Here, in this specification, the object to be processed means an object that is processed while being temporarily fixed to another object by an adhesive film. Also, in this specification, the support member means a member that temporarily fixes the object to be processed by the adhesive film. The workpiece includes, for example, one or more types selected from the group consisting of electronic components and substrates.

[0046] Examples of electronic components include semiconductor chips, semiconductor panels, semiconductor packages, electric elements, display devices, thermal heads, solar cells, etc. Examples of semiconductor chips include ICs, LSIs, discrete devices, light-emitting diodes, light-receiving elements, etc. Examples of electric elements include ceramic capacitors, oscillators, etc. Examples of semiconductor packages include fan-out packages, etc.

[0047] Examples of the substrate include a semiconductor substrate, a package substrate in which a plurality of semiconductor chips are collectively sealed with a sealing resin, a printed circuit board (multilayer ceramic sheet), a green sheet for a multilayer ceramic capacitor, and a thin glass substrate. Examples of the semiconductor substrate include a silicon substrate, a germanium substrate, a gallium-arsenide substrate, a gallium-phosphorus substrate, a gallium-arsenide-aluminum substrate, etc. The semiconductor substrate preferably includes a semiconductor substrate having a circuit formed on its surface. Examples of package substrates in which a plurality of semiconductor chips are collectively sealed with sealing resin include mold array package substrates, fan-out package substrates, and wafer level package substrates. An example of a thin glass substrate is a glass substrate having a thickness of 10 μm or more and 150 μm or less.

[0048] The support member is not particularly limited as long as it can hold the workpiece with an adhesive film. Examples of the support member include a support substrate and a support stand. Examples of the support substrate include a silicon substrate, a glass substrate, a SUS substrate, a copper substrate, and an acrylic substrate.

[0049] The pressure-sensitive adhesive film of this embodiment is capable of temporarily fixing at least one of an electronic component and a substrate. In addition, the adhesive film of the present embodiment can be applied to, for example, one or more types selected from the group consisting of a tape for temporary fixing of electronic components, a tape for processing a substrate, a dicing tape, a backgrinding tape, and a surface protection tape.

[0050] The pressure-sensitive adhesive film of the present embodiment can be used as a tape for temporarily fixing electronic components, for example, to manufacture an electronic device including a fan-out package. That is, in this case, the electronic device of the present embodiment includes a semiconductor package. The semiconductor package includes, for example, a fan-out package. The pressure-sensitive adhesive film of this embodiment may be used as a tape for temporarily fixing electronic components to temporarily fix other types of electronic components.

[0051] The pressure-sensitive adhesive film of the present embodiment can also be used as a dicing tape to temporarily fix electronic components, for example, in the dicing process of electronic components. Examples of the dicing process of electronic components 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.

[0052] The pressure-sensitive adhesive film of this embodiment can also be used as a backgrinding tape to temporarily fix electronic components in the backgrinding process of the electronic components, for example.

[0053] The adhesive film of this embodiment can also be used as a tape for processing substrates, for example, to temporarily fix thin glass substrates in the processing step of the thin glass substrates. The substrate processing tape is not limited to being used for processing thin glass substrates, and may be used in processing other types of substrates.

[0054] The adhesive film of this embodiment can also be used as a surface protection tape, for example, to protect the surface of an object.

[0055] <Composition of adhesive film> Next, the heat-expandable microspheres and each layer constituting the adhesive film used in the method for producing an electronic device of this embodiment will be described.

[0056] [Thermally expandable microspheres] The heat-expandable microspheres are, for example, small spherical resin compositions that expand when heated. The heat-expandable microspheres of this embodiment contain, for example, a thermoplastic resin, a volatile expanding agent, and other additives.

[0057] The heat-expandable microspheres preferably comprise a shell and a volatile expansion agent within the shell. More preferably, the heat-expandable microspheres have a structure in which a volatile expanding agent is encapsulated in the space inside the shell, and such a structure allows the volatile expanding agent to volatilize and turn into a gas upon heating, thereby expanding the shell.

[0058] The shell preferably contains a thermoplastic resin as a material for forming the shell, and examples of the thermoplastic resin used for forming the shell include one or more selected from the group consisting of vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, and polysulfone.

[0059] Volatile blowing agents are substances that become gaseous when heated, and include, 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. The volatile expanding agent preferably contains one or more selected from the group consisting of propane, n-butane, isobutane, n-pentane, isopentane, and neopentane, in order to improve the expansion rate of the heat-expandable microspheres.

[0060] Heat-expandable microspheres can be produced by, for example, the coacervation method or the interfacial polymerization method.

[0061] The sphericity R of the heat-expandable microspheres of this embodiment is 0.93 or more, preferably 0.94 or more, and more preferably 0.95 or more, from the viewpoint of improving the holding power of the object. The upper limit of the sphericity R is not particularly limited, but is, for example, less than 1.00, and may be 0.99 or less, 0.98 or less, or 0.97 or less. The sphericity R of the heat-expandable microspheres of this embodiment is from 0.93 to less than 1.00, preferably from 0.94 to 0.99, more preferably from 0.95 to 0.98, and even more preferably from 0.95 to 0.97, in order to improve the holding power of the target object.

[0062] The sphericity R can be adjusted by, for example, adjusting the type of heat-expandable microspheres and the pretreatment method of the heat-expandable microspheres. The sphericity R can be calculated by the method described in the examples.

[0063] The particle diameter D at 50% cumulative frequency in the volume-based cumulative frequency distribution curve of heat-expandable microspheres measured using a laser diffraction / scattering particle size analyzer. 50 From the viewpoint of improving the releasability of the adhesive film, the thickness is preferably 1 μm or more and 30 μm or less, more preferably 5 μm or more and 25 μm or less, and even more preferably 10 μm or more and 20 μm or less. In addition, particle diameter D 50 Specifically, the method described in the Examples can be used as the measurement method.

[0064] The particle diameter D at 99.9% cumulative frequency in the volume-based cumulative frequency distribution curve of heat-expandable microspheres measured using a laser diffraction / scattering particle size analyzer. 99.9 From the viewpoint of improving the releasability of the adhesive film, the thickness is preferably 10 μm or more and 50 μm or less, more preferably 20 μm or more and 45 μm or less, and even more preferably 30 μm or more and 40 μm or less. In addition, particle diameter D 99.9 Specifically, the method described in the Examples can be used as the measurement method.

[0065] The expansion temperature of the heat-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 heat-expandable microspheres. The upper limit of the expansion temperature of the heat-expandable microspheres is not particularly limited, and 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 expansion temperature of the heat-expandable microspheres is preferably from 160°C to 300°C, more preferably from 165°C to 275°C, even more preferably from 170°C to 250°C, even more preferably from 175°C to 225°C, and even more preferably from 180°C to 200°C, from the viewpoint of facilitating the formation of the adhesive resin layer (C) containing the heat-expandable microspheres.

[0066] [Base material layer (A)] The substrate layer (A) is a layer provided for the purpose of improving the properties of the pressure-sensitive adhesive film, such as ease of handling, mechanical properties, and heat resistance. The substrate layer (A) is not particularly limited, but examples thereof include a resin film. The substrate layer (A) has a first surface A1 and a second surface A2 opposite to the first surface A1.

[0067] The resin constituting the resin film includes, for example, a thermoplastic resin, such as one or more selected from the group consisting of polyolefin, polyester, polyamide, poly(meth)acrylate, polyvinyl chloride, polyvinylidene chloride, polyimide, polyetherimide, ethylene-vinyl acetate copolymer, polyacrylonitrile, polycarbonate, polystyrene, ionomer, polysulfone, polyethersulfone, polyphenylene ether, and aromatic polyether ketone. The polyolefin includes, for example, one or more selected from the group consisting of polyethylene, polypropylene, poly(4-methyl-1-pentene), and poly(1-butene). The polyester includes, for example, one or more selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. The polyamide includes, for example, one or more selected from the group consisting of nylon-6, nylon-66, and polymetaxylene adipamide. The aromatic polyetherketone includes, for example, one or more selected from the group consisting of polyetherketone (PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetheretherketoneketone (PEEKK), and polyetherketone ester.

[0068] From the viewpoint of improving the balance between transparency, mechanical strength, and price, the resin constituting the resin film preferably contains one or more types selected from the group consisting of polypropylene, polyethylene terephthalate, polyethylene naphthalate, polyamide, polyimide, and polyether ether ketone, more preferably contains one or more types selected from the group consisting of polyethylene terephthalate and polyethylene naphthalate, and even more preferably contains polyethylene terephthalate.

[0069] The substrate layer (A) may be a single layer or two or more layers. The resin film for forming the base layer (A) is, for example, a stretched film, and is preferably a uniaxially or biaxially stretched film from the viewpoint of improving the mechanical strength of the base layer (A).

[0070] From the viewpoint of improving film properties, the thickness of the substrate layer (A) is preferably 1 μm or more and 500 μm or less, more preferably 5 μm or more and 400 μm or less, even more preferably 10 μm or more and 300 μm or less, even more preferably 20 μm or more and 200 μm or less, even more preferably 25 μm or more and 100 μm or less, even more preferably 30 μm or more and 50 μm or less, and even more preferably 35 μm or more and 45 μm or less.

[0071] [Adhesive resin layer (B)] The pressure-sensitive adhesive film of the present embodiment may further include a pressure-sensitive adhesive resin layer (B). The adhesive resin layer (B) is a layer located on one surface side (first surface A1 side) of the base layer (A). The adhesive resin layer (B) is a layer that comes into contact with the surface of an object to temporarily fix the object, and is capable of temporarily fixing at least one of an object to be processed and a support member, for example.

[0072] The adhesive resin (B1) constituting the adhesive resin layer (B) preferably contains one or more selected from the group consisting of (meth)acrylic adhesive resins, silicone adhesive resins, urethane adhesive resins, olefin adhesive resins, and styrene adhesive resins, 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 contains a (meth)acrylic adhesive resin, from the viewpoint of facilitating adjustment of adhesive strength.

[0073] 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) crosslinks upon irradiation with radiation and reduces its adhesive strength, making it easier to peel the adhesive film from the target object. Examples of radiation include ultraviolet rays, electron beams, and infrared rays. As the radiation-crosslinked adhesive resin layer, an ultraviolet-crosslinked adhesive resin layer is preferred.

[0074] The adhesive resin layer (B) preferably contains, in addition to the adhesive resin (B1), a crosslinking agent (B2) having two or more crosslinkable functional groups per molecule. The crosslinking agent (B2) reacts with the functional groups of the adhesive resin (B1) to adjust the adhesive strength and cohesive strength of the adhesive resin layer (B).

[0075] The crosslinking agent (B2) includes, for example, one or more selected from the group consisting of epoxy-based crosslinking agents, isocyanate-based crosslinking agents, aziridine-based crosslinking agents, tetrafunctional epoxy-based crosslinking agents, and melamine-based crosslinking agents, and preferably includes one or more selected from the group consisting of epoxy-based crosslinking agents, isocyanate-based crosslinking agents, and aziridine-based crosslinking agents.

[0076] In order to improve the performance balance between the adhesive strength and heat resistance 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.

[0077] From the viewpoint of improving the performance balance between adhesive strength and heat resistance, the total content of the adhesive resin (B1) and the crosslinking agent (B2) in the adhesive resin layer (B) is preferably 50% by mass or more and 100% by mass or less, more preferably 70% by mass or more and 100% by mass or less, even more preferably 90% by mass or more and 100% by mass or less, and even more preferably 95% by mass or more and 100% by mass or less, when the total amount of the adhesive resin layer (B) is taken as 100% by mass.

[0078] In the pressure-sensitive adhesive film of this embodiment, from the viewpoint of reducing the adhesive strength of the adhesive resin layer (C) by heat treatment and enabling the object to be stably held on the adhesive resin layer (B) when the support member is peeled off from the adhesive resin layer (C), the content of heat-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, based on 100% by mass of the total amount of the adhesive resin layer (B).

[0079] From the viewpoint of improving the performance balance between adhesive strength and heat resistance, the thickness of the adhesive resin layer (B) is preferably 1 μm or more and 40 μm or less, more preferably 2 μm or more and 30 μm or less, even more preferably 3 μm or more and 25 μm or less, even more preferably 4 μm or more and 20 μm or less, and even more preferably 5 μm or more and 15 μm or less.

[0080] The adhesive resin layer (B) can be formed, for example, by applying an adhesive to the substrate layer (A). The adhesive may be dissolved in a solvent and applied as a coating liquid, or may be applied as an aqueous emulsion, or the liquid adhesive may be applied directly. In addition, the base material layer (A) and the adhesive resin layer (B) may be formed by co-extrusion molding, or may be formed by laminating a film-like base material layer (A) and a film-like adhesive resin layer (B).

[0081] [Adhesive resin layer (C)] The adhesive resin layer (C) is a layer located on the second surface A2 side of the base layer (A). The adhesive resin layer (C) is preferably a layer whose adhesive strength decreases upon heat treatment, thereby enabling the adhesive film to be peeled off from an object by heat treatment.

[0082] The adhesive resin layer (C) of this embodiment contains heat-expandable microspheres from the viewpoint of improving thermal peelability.

[0083] 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 heat-expandable microspheres in the adhesive resin layer (C).

[0084] 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 adhesive strength). In this specification, loss of adhesive strength means, for example, when the 180° peel strength measured under conditions of 23°C and a pulling rate of 300 mm / min becomes less than 0.5 N / 25 mm. (Method for evaluating adhesive strength reduction) The adhesive resin layer (C) side of the adhesive film is attached to a stainless steel plate and heat-treated at 140°C for 1 hour. Then, it is heated at a temperature of 160°C or higher for 2 minutes. After heating, the peel strength of the adhesive film from the stainless steel plate is measured. The specific heating temperature at 160°C or higher is appropriately determined depending on the type of gas generated, the type of heat-expandable microspheres, the temperature at which the gas is generated, and the temperature at which the heat-expandable microspheres thermally expand (foaming temperature).

[0085] From the viewpoint of improving thermal peelability, the content of the heat-expandable microspheres in the adhesive resin layer (C) is preferably from 5 to 50% by mass, more preferably from 6 to 45% by mass, even more preferably from 7 to 40% by mass, even more preferably from 8 to 35% by mass, even more preferably from 9 to 30% by mass, and even more preferably from 10 to 25% by mass, based on 100% by mass of the total amount of the adhesive resin layer (C).

[0086] From the viewpoint of improving thermal peelability, the content of the heat-expandable microspheres in the adhesive resin layer (C) is preferably 1 part by mass to 150 parts by mass, more preferably 3 parts by mass to 100 parts by mass, even more preferably 5 parts by mass to 50 parts by mass, even more preferably 8 parts by mass to 40 parts by mass, even more preferably 10 parts by mass to 30 parts by mass, and even more preferably 12 parts by mass to 28 parts by mass, based on 100 parts by mass of the adhesive resin (C1) in the adhesive resin layer (C).

[0087] The adhesive resin (C1) constituting the adhesive resin layer (C) includes, for example, one or more 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-based adhesive resins, and styrene-based adhesive resins.

[0088] The adhesive resin (C1) constituting the adhesive resin layer (C) preferably contains one or more selected from the group consisting of (meth)acrylic adhesive resins, silicone adhesive resins, urethane adhesive resins, olefin adhesive resins, and styrene adhesive resins, from the viewpoint of improving thermal peelability. The adhesive resin (C1) constituting the adhesive resin layer (C) more preferably contains a (meth)acrylic adhesive resin, from the viewpoint of making it easier to adjust the adhesive strength.

[0089] Examples of the (meth)acrylic adhesive resin (c) used in the adhesive resin layer (C) include a copolymer containing a (meth)acrylic acid alkyl ester structural unit (c1) and a structural unit (c2) having a functional group capable of reacting with a crosslinking agent (C2).

[0090] The (meth)acrylic adhesive resin (c) can be produced, for example, by copolymerizing a monomer (hereinafter also referred to as monomer (c1)) that forms a (meth)acrylic acid alkyl ester structural unit (c1) and a monomer (hereinafter also referred to as monomer (c2)) that forms a structural unit (c2) having a functional group that can react with a crosslinking agent (C2).

[0091] Monomer (c1) preferably includes one or more selected from the group consisting of (meth)acrylic acid alkyl esters having an alkyl group of about 1 to 12 carbon atoms, more preferably (meth)acrylic acid alkyl esters having an alkyl group of 1 to 8 carbon atoms, and even more preferably methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate.

[0092] The content of the structural 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 taken as 100% by mass.

[0093] 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, itaconic acid monoalkyl ester, mesaconic acid monoalkyl ester, citraconic acid monoalkyl ester, fumaric acid monoalkyl ester, maleic acid monoalkyl ester, glycidyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, (meth)acrylamide, and t-butylaminoethyl (meth)acrylate. The monomer (c2) preferably includes one or more selected from the group consisting of (meth)acrylic acid, 2-hydroxyethyl (meth)acrylate, and (meth)acrylamide.

[0094] The content of the structural unit (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 taken as 100% by mass.

[0095] The polymerization reaction mechanism of the (meth)acrylic adhesive resin (c) may be radical polymerization, anionic polymerization, cationic polymerization, etc. The polymerization reaction mechanism of the (meth)acrylic adhesive resin (c) is preferably radical polymerization from the viewpoints of the production cost of the (meth)acrylic adhesive resin (c), the influence of functional groups of the monomer, the influence of ions on the surface of the target object, etc.

[0096] 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 may include, for example, one or more selected from the group consisting of benzoyl peroxide, di-t-butyl peroxide, dicumyl peroxide, 3,3,5-trimethylhexanoyl peroxide, di-2-ethylhexyl peroxydicarbonate, methyl ethyl ketone peroxide, t-butyl peroxyphthalate, t-butyl peroxybenzoate, di-t-butyl peroxyacetate, t-butyl peroxyisobutyrate, t-butyl peroxy-2-hexanoate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxy-3,5,5-trimethylhexanoate, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, t-butyl peroxide, and di-t-amyl peroxide. The inorganic peroxide includes, for example, one or more selected from the group consisting of ammonium persulfate, potassium persulfate, and sodium persulfate. The azo compound includes, for example, one or more selected from the group consisting of 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, and 4,4'-azobis-4-cyanovaleric acid.

[0097] The radical polymerization initiator in the (meth)acrylic adhesive resin (c) preferably contains an organic peroxide, more preferably t-butylperoxy-2-ethylhexanoate, from the viewpoint of improving the performance balance between adhesive strength and heat resistance of the adhesive resin layer (C).

[0098] The adhesive resin layer (C) preferably further contains a crosslinking agent (C2) having two or more crosslinkable functional groups in one molecule in addition to the adhesive resin (C1). The crosslinking agent (C2) reacts with the functional groups of the adhesive resin (C1) and is used to adjust the adhesive strength and cohesive strength of the adhesive resin layer (C).

[0099] The crosslinking agent (C2) includes, for example, one or more selected from the group consisting of epoxy-based crosslinking agents, isocyanate-based crosslinking agents, aziridine-based crosslinking agents, tetrafunctional epoxy-based crosslinking agents, and melamine-based crosslinking agents. The epoxy-based 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 resorcinol diglycidyl ether. The isocyanate-based crosslinking agent includes, for example, one or more selected from the group consisting of tetramethylene diisocyanate, hexamethylene diisocyanate, a toluene diisocyanate triadduct of trimethylolpropane, polyisocyanate, diphenylmethane diisocyanate, and tolylene diisocyanate. The aziridine crosslinking agent includes, for example, one or more selected from the group consisting of trimethylolpropane-tri-β-aziridinylpropionate, tetramethylolmethane-tri-β-aziridinylpropionate, N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide), N,N'-hexamethylene-1,6-bis(1-aziridinecarboxamide), N,N'-toluene-2,4-bis(1-aziridinecarboxamide), and trimethylolpropane-tri-β-(2-methylaziridine)propionate. The tetrafunctional epoxy crosslinking agent includes, for example, one or more selected from the group consisting of N,N,N',N'-tetraglycidyl-m-xylylenediamine and 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane. Melamine-based crosslinking agents include, for example, hexamethoxymethylolmelamine.

[0100] In the adhesive resin layer (C), the crosslinking agent (C2) preferably contains one or more crosslinking agents selected from the group consisting of epoxy-based crosslinking agents, isocyanate-based crosslinking agents, and aziridine-based crosslinking agents, from the viewpoint of improving the performance balance between adhesive strength and thermal peelability.

[0101] The content of the crosslinking agent (C2) in the adhesive resin layer (C) is preferably within a range such that the number of functional groups in the crosslinking agent (C2) is not greater than the number of functional groups in the adhesive resin (C1). However, if necessary, an excess amount of the crosslinking agent (C2) may be added when new functional groups are generated by the crosslinking reaction or when the crosslinking reaction is slow. The lower limit of the content of the crosslinking agent (C2) in the adhesive resin layer (C) is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 2 parts by mass or more, when the content of the adhesive resin (C1) in the adhesive resin layer (C) is 100 parts by mass, in order to improve the performance balance between adhesive strength and thermal peelability. In addition, from the viewpoint of improving storage stability, the upper limit of the content of the crosslinking agent (C2) in the adhesive resin layer (C) is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 4 parts by mass or less, when the content of the adhesive resin (C1) in the adhesive resin layer (C) is 100 parts by mass.

[0102] The adhesive resin layer (C) preferably further contains a tackifier resin (C3) from the viewpoint of improving adhesive strength. When the adhesive resin layer (C) contains the tackifier resin (C3), it becomes easy to adjust the adhesion to the object at around room temperature.

[0103] The tackifier resin (C3) includes, for example, one or more resins selected from the group consisting of rosin-based resins, terpene-based resins, natural rosin resins, petroleum resins, and coumarone-indene-based resins. The rosin-based resin includes, for example, a rosin-based derivative that has been treated by esterification or the like. The terpene-based resin includes, for example, one or more resins selected from the group consisting of α-pinene-based resins, β-pinene-based resins, dipentene-based resins, and terpene-phenol-based resins. The natural rosin resin includes one or more resins selected from the group consisting of gum-based resins, wood-based resins, and tall oil-based resins. Petroleum resins include, for example, resins obtained by hydrogenating, disproportionating, polymerizing, or maleating natural rosin resins.

[0104] In the adhesive resin layer (C) of this embodiment, the softening point of the tackifier resin (C3) is preferably 100°C or higher and 160°C or lower, more preferably 120°C or higher and 150°C or lower, from the viewpoint of reducing contamination of the object and improving adhesion to the object.

[0105] From the viewpoint of improving adhesion to the object during work, the content of the tackifier 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. The content of the tackifier 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 taken as 100 parts by mass, in order to improve the performance balance between adhesion to the object and stickiness at room temperature.

[0106] The adhesive resin layer (C) may contain additives such as a plasticizer as other components.

[0107] The lower limit of the total content of the adhesive resin (C1), crosslinking agent (C2), tackifier resin (C3) and heat-expandable microspheres in the adhesive resin layer (C) is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more, when the total amount of the adhesive resin layer (C) is taken as 100% by mass. The upper limit is not particularly limited, but is, for example, 100% by mass or less.

[0108] The adhesive resin layer (C) may be a single layer or multiple layers.

[0109] 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 still more preferably 25 μm or more, from the viewpoint of improving the balance of adhesiveness and thermal releasability. From the viewpoint of improving the handleability of the adhesive film 10, 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. 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 performance balance of adhesiveness, thermal peelability, and handling properties.

[0110] The adhesive resin layer (C) can be formed, for example, by applying an adhesive coating liquid onto the base layer (A), or by transferring the adhesive resin layer (C) formed on a separator onto the base layer (A). Examples of methods for applying the adhesive coating liquid include roll coater method, reverse roll coater method, gravure roll method, bar coater method, comma coater method, and die coater method.

[0111] There are no particular restrictions on the drying conditions for the applied adhesive, but for example, drying is performed for 15 seconds to 5 minutes at 80 to 170°C. To sufficiently promote the crosslinking reaction between the crosslinking agent and the adhesive, after drying of the adhesive coating liquid is complete, heating may be performed at 40 to 80°C for approximately 5 to 300 hours.

[0112] The base material layer (A) and the adhesive resin layer (C) may be formed by co-extrusion molding, or may be formed by laminating a film-like base material layer (A) and a film-like adhesive resin layer (C).

[0113] [Middle layer (D)] The pressure-sensitive adhesive film of the present embodiment may further include an intermediate layer (D). The intermediate layer (D) is a layer provided as, for example, an irregularity-absorbing resin layer, an impact-absorbing layer, an anchor coat layer, or the like.

[0114] The intermediate layer (D) preferably contains a thermoplastic resin. When the pressure-sensitive adhesive film of the present embodiment is used, for example, in a tape for temporary fixing of electronic components, the intermediate layer (D) more preferably contains one or more resins selected from the group consisting of polyolefin-based resins, polystyrene-based resins, (meth)acrylic resins, urethane-based resins, silicone-based resins, polyester-based resins, polyamide-based resins, and fluorine-based resins, and even more preferably contains one or more resins selected from the group consisting of polyolefin-based resins, polystyrene-based resins, and (meth)acrylic resins.

[0115] When the pressure-sensitive adhesive film of this embodiment is used, for example, as a tape for temporary fixing of electronic components, the thickness of the intermediate layer (D) is preferably 5 μm or more and 100 μm or less, more preferably 10 μm or more and 50 μm or less, and even more preferably 15 μm or more and 25 μm or less, from the viewpoint of improving the unevenness absorbency of the pressure-sensitive adhesive film.

[0116] The intermediate layer (D) preferably contains a thermoplastic resin. When the pressure-sensitive adhesive film of this embodiment is used, for example, as a dicing tape, the intermediate layer (D) more preferably contains one or more materials selected from the group consisting of olefin-based 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. The olefin-based resin includes, for example, one or more selected from the group consisting of ethylene-based resin, propylene polymer, 1-butene polymer, 4-methyl-1-pentene polymer, ethylene-α-olefin copolymer, ethylene-cyclic olefin copolymer, ethylene-α-olefin-cyclic olefin copolymer, ethylene-α-olefin-non-conjugated polyene copolymer, ethylene-α-olefin-conjugated polyene copolymer, ethylene-aromatic vinyl copolymer, ethylene-α-olefin-aromatic vinyl copolymer, and copolymers thereof. The ethylene-based resin may include, for example, one or more selected from the group consisting of high-density polyethylene-based resin (HDPE), medium-density polyethylene-based resin (MDPE), low-density polyethylene-based resin (LDPE), ultra-low-density polyethylene-based resin (ULDPE), and linear low-density polyethylene-based resin (LLDPE). The ethylene-(meth)acrylic acid ester copolymer includes, for example, one or more selected from the group consisting of ethylene-ethyl (meth)acrylate copolymer, ethylene-methyl (meth)acrylate copolymer, ethylene-propyl (meth)acrylate copolymer, ethylene-butyl (meth)acrylate copolymer, ethylene-hexyl (meth)acrylate copolymer, ethylene-2-hydroxyethyl (meth)acrylate copolymer, ethylene-2-hydroxypropyl (meth)acrylate copolymer, and ethylene-glycidyl (meth)acrylate copolymer. The ethylene-vinyl ester copolymer includes, 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.

[0117] When the pressure-sensitive adhesive film of this embodiment is used, for example, as a dicing tape, the intermediate layer (D) more preferably contains one or more types selected from the group consisting of ethylene-α-olefin copolymers and ethylene-vinyl ester copolymers, more preferably contains one or more types selected from the group consisting of ethylene-α-olefin copolymers and ethylene-vinyl acetate copolymers, and even more preferably contains an ethylene-vinyl acetate copolymer.

[0118] When the pressure-sensitive adhesive film of the present embodiment is used, for example, as a dicing tape, the content of vinyl acetate units in the ethylene-vinyl acetate copolymer in the pressure-sensitive adhesive film of the present embodiment is preferably 10% by mass or more and 35% by mass or less, more preferably 12% by mass or more and 30% by mass or less, and even more preferably 15% by mass or more and 25% by mass or less, when the total amount of the ethylene-vinyl acetate copolymer is taken as 100% by mass, from the viewpoint of improving the performance balance of crosslinkability, flexibility, weather resistance, and transparency. The vinyl acetate content can be measured, for example, in accordance with JIS K6730:1994.

[0119] When the pressure-sensitive adhesive film of the present embodiment is used, for example, as a dicing tape, the carbon number of the α-olefin of the ethylene-α-olefin copolymer used as the thermoplastic resin in the pressure-sensitive adhesive film of the present embodiment is preferably 3 or more and 20 or less, more preferably 3 or more and 10 or less, and even more preferably 3 or more and 8 or less. The α-olefin used in the ethylene-α-olefin copolymer includes, for example, one or more selected from the group consisting of propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3,3-dimethyl-1-butene, 4-methyl-1-pentene, 1-octene, 1-decene, and 1-dodecene. The α-olefin used in the ethylene-α-olefin copolymer preferably includes one or more selected from the group consisting of propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, and 1-octene, from the viewpoint of availability. The ethylene-α-olefin copolymer may be a random copolymer or a block copolymer, but from the viewpoint of flexibility, a random copolymer is preferred.

[0120] The intermediate layer (D) may contain other components such as additives such as a plasticizer. The intermediate layer (D) may be a single layer or multiple layers.

[0121] <Structure of adhesive film> The structure of the adhesive film 10 of this embodiment will be described with reference to several exemplary embodiments. The adhesive film 10 of this embodiment may have a structure as shown in FIG. 4 or FIG. 5 below, for example.

[0122] In the adhesive film 10 of this embodiment, the surface on the adhesive resin layer (C) side is in contact with the support member 30. In this case, the object 20 is located on the first surface A1 side of the base material layer (A) of the adhesive film 10, and the support member 30 is located on the second surface A2 side of the base material layer (A). The adhesive film 10 of this embodiment may have a structure as shown in the following FIGS. 4 and 5, for example.

[0123] 4 further includes 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).

[0124] The adhesive film 10 in FIG. 4 is in contact with the object 20 on the adhesive resin layer (B) side and with the support member 30 on the adhesive resin layer (C) side. The adhesive film 10 in Fig. 4 temporarily fixes the object 20 to be processed by the adhesive resin layer (B). Moreover, the adhesive film 10 in Fig. 4 is temporarily fixed to the support member 30 by the adhesive resin layer (C).

[0125] The adhesive film 10 in Fig. 4 may further include an intermediate layer (D) between the base material layer (A) and the adhesive resin layer (B), or between the base material layer (A) and the adhesive resin layer (C), as needed. Note that the intermediate layer (D) is not shown in Fig. 4. 4 may further include 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), as necessary. In this case, the intermediate layer (D) located between the base material 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 material layer (A) and the adhesive resin layer (C).

[0126] The adhesive film 10 of FIG. 5 is the adhesive film 10 of FIG. 4, which further comprises an intermediate layer (D) between the base material layer (A) and the adhesive resin layer (C).

[0127] <Method for manufacturing adhesive film> Next, an example of a method for producing the adhesive film 10 of this embodiment will be described. The adhesive film 10 of this embodiment can be formed, for example, by a method of applying an adhesive resin layer (C) onto a base layer (A), or by a method of transferring an adhesive resin layer (C) formed on a separator onto the base layer (A). The adhesive film 10 of the present embodiment may be formed by laminating the base material layer (A) and the adhesive resin layer (C) in this order. The adhesive film 10 of the present embodiment may be formed by co-extrusion molding the base material layer (A) and the adhesive resin layer (C) in this order.

[0128] An example of a method for providing the adhesive resin layer (C) on the base layer (A) is a method of applying an adhesive coating liquid capable of forming the adhesive resin layer (C). Examples of methods for applying the adhesive coating liquid include a roll coater method, a reverse roll coater method, a gravure roll method, a bar coater method, a comma coater method, and a die coater method. There are no particular restrictions on the drying conditions for the adhesive coating liquid, but drying is preferably performed 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 order to sufficiently promote the crosslinking reaction between the crosslinking agent and the adhesive resin in the adhesive coating liquid, the adhesive coating liquid may be heated at a temperature range of 40 to 80°C for about 5 to 300 hours after drying is complete.

[0129] When 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 a method of applying the adhesive resin layer (B) and the adhesive resin layer (C) respectively onto the base layer (A), or by a method of transferring the adhesive resin layer (B) and the adhesive resin layer (C) formed on a separator respectively onto the base layer (A). Furthermore, when the adhesive film 10 of this embodiment includes an adhesive resin layer (B), the adhesive film 10 of this embodiment may be formed by laminating the adhesive resin layer (B), the base layer (A), and the adhesive resin layer (C) in this order. Furthermore, the adhesive film 10 of this embodiment may be formed by co-extrusion molding the adhesive resin layer (B), the base layer (A), and the adhesive resin layer (C) in this order.

[0130] When the adhesive film 10 of this embodiment further comprises an intermediate layer (D), for example, the adhesive film 10 of this embodiment, in the case of the adhesive film 10 shown in Figure 5, can be formed by a method of laminating the adhesive resin layer (B), base material layer (A), intermediate layer (D), and adhesive resin layer (C) in this order; a method of co-extrusion molding the adhesive resin layer (B), base material layer (A), intermediate layer (D), and adhesive resin layer (C) in this order; a method of laminating the base material layer (A) and the intermediate layer (D), and then applying the adhesive resin layer (B) and the adhesive resin layer (C), respectively; a method of laminating the base material layer (A) and the intermediate layer (D), and then transferring the adhesive resin layer (B) and the adhesive resin layer (C), which have been formed on a separator, respectively.

[0131] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations can also be adopted. Furthermore, the present invention is not limited to the above-described embodiment, and modifications and improvements within the scope that do not impair the effects of the present invention are included in the present invention. [Example]

[0132] The present embodiment will be described in detail below with reference to examples, etc. However, the present embodiment is not limited to the descriptions of these examples.

[0133] Details of the materials used to prepare the adhesive film are as follows.

[0134] <Adhesive resin solution SB1> Deionized pure water was charged with 0.5 parts by weight of 4,4'-azobis-4-cyanovaleric acid (Otsuka Chemical Co., Ltd., trade name: ACVA) as a polymerization initiator, 74.3 parts by weight of n-butyl acrylate, 13.7 parts by weight of methyl methacrylate, 9 parts by weight of 2-hydroxyethyl methacrylate, and 3 parts by weight of the ammonium salt of polyoxyethylene nonylphenyl ether sulfate ester with a polymerizable 1-propenyl group introduced into the benzene ring (Dai-ichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon HS-1025). The emulsion polymerization was carried out with stirring at 70-72°C for 8 hours to obtain an acrylic resin emulsion. This was neutralized with aqueous ammonia (pH = 7.0) to obtain adhesive resin solution SB1 with a solids concentration of 42.5%.

[0135] <Adhesive resin solution SB2> In deionized water, 0.5 parts by weight of ammonium persulfate as a polymerization initiator, 63 parts by weight of 2-ethylhexyl acrylate, 21 parts by weight of n-butyl acrylate, 9 parts by weight of methyl methacrylate, 3 parts by weight of 2-hydroxyethyl methacrylate, 1 part by weight of polytetramethylene glycol diacrylate (NOF Corporation, product name: ADT-250), and 2 parts by weight of a polyoxyethylene nonylphenyl ether sulfate ammonium salt with a polymerizable 1-propenyl group attached to the benzene ring (Dai-ichi Kogyo Seiyaku Co., Ltd., product name: Aqualon HS-1025) were added and emulsion polymerized with stirring at 70-72°C for 8 hours to obtain an acrylic resin emulsion. This was neutralized with aqueous ammonia (pH = 7.0) to obtain adhesive resin solution SB2 with a solids concentration of 56.5%.

[0136] <Adhesive coating liquid B1> 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 (Ex-1610, manufactured by Nagase ChemteX Corporation) serving as a crosslinking agent were mixed together to obtain adhesive coating solution B1.

[0137] <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 NOF Corporation, 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, and solution polymerization was carried out with stirring at 83 to 87°C for 11 hours to obtain an acrylic resin solution with a solids concentration of 45% by mass. This was designated adhesive resin solution SC1.

[0138] <Adhesive coating liquid C1> 100 parts by mass of the adhesive resin solution SC1 and 0.9 parts by mass (2 parts by mass per 100 parts by mass of adhesive resin) of an isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals, Inc., trade name: Olestar P49-75S) were mixed, and the solid content concentration was adjusted to 40% with ethyl acetate to obtain adhesive coating solution C1.

[0139] The heat-expandable microspheres used in the adhesive resin layer (C) are explained below.

[0140] ·Thermally expandable microspheres 1 Heat-expandable microspheres (trade name: Advancell EM-503, manufactured by Sekisui Chemical Co., Ltd.) were passed through a sieve with 38 μm openings, and the heat-expandable microspheres that passed through the sieve were collected to obtain heat-expandable microspheres 1. The sphericity R measured according to the following (method for measuring sphericity) was 0.94. The volume-based cumulative frequency distribution curve of the heat-expandable microspheres 1 was measured according to the following method for measuring particle size distribution. The particle diameter D at the cumulative frequency of 99.9% in the volume-based cumulative frequency distribution curve of the heat-expandable microspheres 1 was 99.9 In the cumulative frequency distribution curve of the heat-expandable microspheres 1 based on volume, the particle diameter D 50 was 15.5 μm.

[0141] (Method for measuring sphericity) 0.2 g of heat-expandable microspheres 1 were mixed with 50 mL of pure water to prepare Mixed Solution 1. Mixed Solution 1 was then ultrasonically treated for 10 minutes using an ultrasonic cleaning device (product name: AS12GTU, manufactured by AS ONE Corporation) to disperse the heat-expandable microspheres 1 in the pure water, thereby preparing Sample 1.

[0142] Next, Sample 1 was placed in a flow-type particle image analyzer (product name: FPIA-3000, manufactured by Sysmex Corporation). Sample 1 was passed through the imaging cell of the flow-type particle image analyzer to capture a still image of the heat-expandable microspheres 1. The image of the heat-expandable microspheres 1 projected onto a plane was taken as a particle image of the heat-expandable microspheres 1 (hereinafter also referred to as a particle image). The perimeter of a particle in the particle image was taken as the perimeter of the particle image. The area of ​​a particle in the particle image was taken as the particle area of ​​the particle image.

[0143] Next, the circle equivalent diameter of the particle image was calculated using the following formula (2). Equation (2): (Circle equivalent diameter) = 2 × {(particle area) / π} 1 / 2 Next, the circularity of the particle image was calculated using the following formula (3). Equation (3): (Circularity) = [2 × {(particle area) × π} 1 / 2 ] / (perimeter)

[0144] Finally, particle images were taken of 20,519 randomly selected heat-expandable microspheres 1. The perimeter, particle area, equivalent circle diameter, and circularity were calculated for each particle image. The sphericity R was calculated using the above formula (1).

[0145] (Method for measuring particle size distribution) 0.2 g of heat-expandable microspheres 1 were placed in a 500 mL beaker. 50 mL of pure water and 0.1 mL of surfactant were then added to the 500 mL beaker and stirred with a glass rod for 1 minute. The surfactant used was an aqueous solution of Triton X-100 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) diluted 500 times with pure water. Next, Sample 2 was prepared by dispersing the heat-expandable microspheres 1 in pure water using an ultrasonic cleaning device (product name: AS12GTU, manufactured by AS ONE Corporation). The 500 mL beaker containing Sample 2 was then placed in a laser diffraction particle size distribution analyzer (product name: Mastersizer, manufactured by Malvern Panalytical). The volume-based cumulative frequency distribution curve of the heat-expandable microspheres 1 was measured using the laser diffraction scattering method.

[0146] ·Thermally expandable microspheres 2 Heat-expandable microspheres (manufactured by Kureha Corporation, trade name: S2340D) were passed through a sieve with 38 μm openings, and the heat-expandable microspheres that passed through the sieve were collected to obtain heat-expandable microspheres 2. The sphericity R measured in the same manner as above (method of measuring sphericity) was 0.95.

[0147] ·Thermally expandable microspheres 3 Heat-expandable microspheres (trade name: Advancell EM-503, manufactured by Sekisui Chemical Co., Ltd.) were left untreated to prepare heat-expandable microspheres 3. The sphericity R measured in the same manner as above (method of measuring sphericity) was 0.90. The volume-based cumulative frequency distribution curve of the heat-expandable microspheres 3 was measured in the same manner as described above (Method for measuring particle size distribution). The particle diameter D at the cumulative frequency of 99.9% in the volume-based cumulative frequency distribution curve of the heat-expandable microspheres 3 was 99.9 In the cumulative frequency distribution curve of the heat-expandable microspheres 3 based on volume, the particle diameter D 50 was 16.2 μm.

[0148] ·Thermally expandable microspheres 4 Heat-expandable microspheres (manufactured by Sekisui Chemical Co., Ltd., trade name: Advancell EM-503) were passed through a sieve with 100 μm openings, and the heat-expandable microspheres that passed through the sieve were collected to obtain heat-expandable microspheres 4. The sphericity R measured in the same manner as above (method of measuring sphericity) was 0.92. The volume-based cumulative frequency distribution curve of the heat-expandable microspheres 4 was measured in the same manner as described above (Method for measuring particle size distribution). The particle diameter D at the cumulative frequency of 99.9% in the volume-based cumulative frequency distribution curve of the heat-expandable microspheres 4 was 99.9 In the cumulative frequency distribution curve of the heat-expandable microspheres 4 based on volume, the particle diameter D 50 was 15.3 μm.

[0149] ·Thermally expandable microspheres 5 Heat-expandable microspheres (manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd., trade name: FN180S) were passed through a sieve with 50 μm openings, and the heat-expandable microspheres that passed through the sieve were collected to give heat-expandable microspheres 5. The sphericity R measured in the same manner as above (method of measuring sphericity) was 0.88. The volume-based cumulative frequency distribution curve of the heat-expandable microspheres 5 was measured in the same manner as described above (Method for measuring particle size distribution). The particle diameter D at the cumulative frequency of 99.9% in the volume-based cumulative frequency distribution curve of the heat-expandable microspheres 5 was 99.9 In the cumulative frequency distribution curve of the heat-expandable microspheres 5 based on volume, the particle diameter D 50 was 15.4 μm.

[0150] <Adhesive coating liquid C2> Adhesive coating solution C2 was prepared by mixing 100 parts by mass of adhesive resin solution SC1, 2.25 parts by mass of a 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 an isocyanate crosslinker (manufactured by Mitsui Chemicals, Inc., product name: Olester P49-75S) (2.67 parts by mass per 100 parts by mass of adhesive resin), and 6.75 parts by mass of heat-expandable microspheres 1 (15 parts by mass per 100 parts by mass of adhesive resin), and adjusting the solids concentration to 30% with ethyl acetate.

[0151] <Adhesive coating liquid C3> Adhesive coating solution C3 was prepared by mixing 100 parts by mass of adhesive resin solution SC1, 2.25 parts by mass of a 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 an isocyanate crosslinker (manufactured by Mitsui Chemicals, Inc., product name: Olester P49-75S) (2.67 parts by mass per 100 parts by mass of adhesive resin), and 6.75 parts by mass of heat-expandable microspheres 2 (15 parts by mass per 100 parts by mass of adhesive resin), and adjusting the solids concentration to 30% with ethyl acetate.

[0152] <Adhesive coating liquid C4> Adhesive coating solution C4 was prepared by mixing 100 parts by mass of adhesive resin solution SC1, 2.25 parts by mass of a 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 an isocyanate crosslinker (manufactured by Mitsui Chemicals, Inc., product name: Olester P49-75S) (2.67 parts by mass per 100 parts by mass of adhesive resin), and 6.75 parts by mass of heat-expandable microspheres 3 (15 parts by mass per 100 parts by mass of adhesive resin), and adjusting the solids concentration to 30% with ethyl acetate.

[0153] <Adhesive coating liquid C5> Adhesive coating solution C5 was prepared by mixing 100 parts by mass of adhesive resin solution SC1, 2.25 parts by mass of a polymerized rosin ester-based 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 an isocyanate-based crosslinker (manufactured by Mitsui Chemicals, Inc., product name: Olester P49-75S) (2.67 parts by mass per 100 parts by mass of adhesive resin), and 6.75 parts by mass of heat-expandable microspheres 4 (15 parts by mass per 100 parts by mass of adhesive resin), and adjusting the solids concentration to 30% with ethyl acetate.

[0154] <Adhesive coating liquid C6> 100 parts by mass of the adhesive resin solution SC1, 2.25 parts by mass of a polymerized rosin ester-based tackifier (manufactured by Arakawa Chemical Industries, Ltd., product name: Pencel D-125) (5 parts by mass per 100 parts by mass of the adhesive resin), 1.2 parts by mass of an isocyanate-based crosslinker (manufactured by Mitsui Chemicals, Inc., product name: Olester P49-75S) (2.67 parts by mass per 100 parts by mass of the adhesive resin), and 6.75 parts by mass of heat-expandable microspheres 5 (15 parts by mass per 100 parts by mass of the adhesive resin) were mixed, and the solids concentration was adjusted to 30% with ethyl acetate to prepare an adhesive coating solution C6.

[0155] [Example 1] A 10 μm thick adhesive resin layer (B) was formed by drying adhesive coating solution B1 on a polyethylene terephthalate (PET) film (38 μm thick) as the base layer (A). Next, a 20 μm thick intermediate layer (D) was formed by drying adhesive coating solution C1 on the surface opposite to the adhesive resin layer (B) of the PET film, and a 30 μm thick heat-peelable adhesive resin layer (C) was formed by drying adhesive coating solution C2 on top of that to obtain an adhesive film.

[0156] [Example 2] A 10 μm thick adhesive resin layer (B) was formed by drying adhesive coating solution B1 on a polyethylene terephthalate (PET) film (38 μm thick) as the base layer (A). Next, a 20 μm thick intermediate layer (D) was formed by drying adhesive coating solution C1 on the surface opposite to the adhesive resin layer (B) of the PET film, and a 30 μm thick heat-peelable adhesive resin layer (C) was formed by drying adhesive coating solution C3 on top of that to obtain an adhesive film.

[0157] [Comparative Example 1] A 10 μm thick adhesive resin layer (B) formed by drying adhesive coating solution B1 was provided on a polyethylene terephthalate (PET) film (38 μm thick) as the base layer (A). Next, a 20 μm thick intermediate layer (D) formed by drying adhesive coating solution 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 solution C4 was provided on top of that to obtain an adhesive film.

[0158] Comparative Example 2 A 10 μm thick adhesive resin layer (B) formed by drying adhesive coating solution B1 was provided on a polyethylene terephthalate (PET) film (38 μm thick) as the base layer (A). Next, a 20 μm thick intermediate layer (D) formed by drying adhesive coating solution 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 solution C5 was provided on top of that to obtain an adhesive film.

[0159] Comparative Example 3 A 10 μm thick adhesive resin layer (B) was formed by drying adhesive coating solution B1 on a polyethylene terephthalate (PET) film (38 μm thick) as the base layer (A). Next, a 20 μm thick intermediate layer (D) was formed by drying adhesive coating solution C1 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) was formed by drying adhesive coating solution C6 on top of that to obtain an adhesive film.

[0160] (Examples 1 to 2, Comparative Examples 1 to 3) The physical properties of the adhesive film of each example were measured by the following methods. The measurement results are shown in Table 1.

[0161] <Evaluation method for chip flying> The adhesive film of each example was used to carry out the following procedure. The adhesive resin layer (C) side of the adhesive film was attached to a circular SUS substrate (material: SUS304) having a diameter of 320 mm and a thickness of 1.5 mm. Next, 1,300 electronic components (4.7 mm × 3.9 mm chips) were placed on the adhesive resin layer (B) of the adhesive film and adhered to each other to obtain Structure 1. Thereafter, Structure 1 was heated at 130°C for 30 minutes. Next, using a compression molding machine, the chip on the adhesive resin layer (B) was encapsulated by compression molding using a liquid epoxy resin encapsulant (manufactured by Sumitomo Bakelite Co., Ltd., product name: G730) at 125°C for 500 seconds, and then heated (post-mold cured) at 150°C for 1 hour, thereby obtaining a structure 2 in which the electronic components were encapsulated with epoxy resin. Next, the structure 2 was heated at 190°C for 60 seconds to debond the support substrate from the structure 2, thereby obtaining a structure 3. In this specification, debonding means peeling off the object (here, the support substrate) from the adhesive film by reducing the adhesive strength of the adhesive resin layer (C) of the adhesive film through heat treatment. Next, the adhesive film was peeled off from Structure 3 at an angle of 180° while heated to 100°C, thereby obtaining Structure 4. Next, the structure 4 was visually inspected for the presence or absence of chipping. This evaluation was carried out under the condition that the number of samples was n = 2. The average value for each sample was taken as the number of chips. The number of chips that flew off was evaluated as A when it was less than 5, B when it was 5 or more but less than 20, and C when it was 20 or more.

[0162] <Evaluation method for epoxy resin indentations> The adhesive film of each example was used to carry out the following procedure. For Structure 4 obtained by the above <Method for evaluating chipping>, the surface of the epoxy resin that had been in contact with the adhesive film was observed to visually check for the presence or absence of epoxy resin dents. This evaluation was carried out under the condition that the number of samples was n = 2. The average value for each sample was taken as the number of epoxy resin dents. The case where the number of epoxy resin dents was less than 5 was evaluated as A, the case where the number was 5 or more but less than 20 was evaluated as B, and the case where the number was 20 or more was evaluated as C. [Table 1]

[0163] This application claims priority based on Japanese Patent Application No. 2024-168464, filed September 27, 2024, the disclosure of which is incorporated herein in its entirety. [Explanation of symbols]

[0164] 10 adhesive film 20 Processing object 24 Electronic Components 30 Support member 31 Support substrate 40 Workpiece after processing 50 Encapsulating material 100 structures 400 structure 500 Electronic equipment 510 wiring layer 520 Bump 600 Electronic equipment A. Substrate layer A1 Side 1 Page A2, Page 2 B. Adhesive resin layer C Adhesive resin layer D Intermediate layer

Claims

1. A step of preparing a structure including an adhesive film having a base layer (A), an adhesive resin layer (B), and an adhesive resin layer (C), an object to be processed temporarily fixed to the adhesive resin layer (B), and a support member temporarily fixed to the adhesive resin layer (C); and processing the object temporarily fixed to the adhesive resin layer (B), the base material layer (A) is located between the adhesive resin layer (B) and the adhesive resin layer (C), the adhesive resin layer (C) contains heat-expandable microspheres, The method for producing an electronic device, wherein the heat-expandable microspheres have a sphericity R of 0.93 or more as calculated by the following formula (1): [Equation 1] (In the formula (1), n ​​represents the total number of the heat-expandable microspheres, i represents an integer of 1 or more and n or less, and X ｉ represents the equivalent circle diameter of the ith heat-expandable microsphere, and Y ｉ indicates the circularity of the ith heat-expandable microsphere.

2. the particle diameter D at 50% cumulative frequency in the volume-based cumulative frequency distribution curve of the heat-expandable microspheres measured using a laser diffraction / scattering particle size distribution analyzer; ５０ The method for manufacturing an electronic device according to claim 1 , wherein the thickness of the first and second electrodes is 1 μm or more and 30 μm or less.

3. the particle diameter D at a cumulative frequency of 99.9% in a volume-based cumulative frequency distribution curve of the heat-expandable microspheres measured using a laser diffraction / scattering particle size distribution analyzer; ９９．９ The method for manufacturing an electronic device according to claim 1 or 2, wherein the thickness of the first and second electrodes is 10 μm or more and 50 μm or less.

4. 3. The method for manufacturing an electronic device according to claim 1, wherein the expansion temperature of the heat-expandable microspheres is 160°C or higher.

5. The method for producing an electronic device according to claim 1 or 2, wherein the adhesive resin layer (C) is a layer whose adhesive strength decreases upon heat treatment.

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

7. 3. The method for producing an electronic device according to claim 1, wherein the content of the heat-expandable microspheres in the adhesive resin layer (C) is 5% by mass or more and 50% by mass or less, based on 100% by mass of the total amount of the adhesive resin layer (C).

8. 3. The method for producing an electronic device according to claim 1, wherein the base material layer (A) comprises one or more materials selected from the group consisting of polypropylene, polyethylene terephthalate, polyethylene naphthalate, polyamide, polyimide, and polyether ether ketone.

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

10. The method for manufacturing an electronic device according to claim 1 or 2, wherein the adhesive resin layer (B) has a thickness of 1 μm or more and 40 μm or less.

11. 3. The method for manufacturing an electronic device according to claim 1, further comprising providing an intermediate layer (D) at least one 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).

12. The method for manufacturing an electronic device according to claim 11, wherein the thickness of the intermediate layer (D) is 5 μm or more and 100 μm or less.

13. The method for manufacturing an electronic device according to claim 1 or 2, wherein the electronic device comprises a semiconductor package.

14. The method of manufacturing an electronic device according to claim 13 , wherein the semiconductor package comprises a fan-out package.

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