Electronic device production method

Abstract

An electronic device production method comprising: a step (A) for preparing a structure (a) (200) including a laminate (100) that is provided with an epoxy resin layer (10), a base material layer (40), and an adhesive resin layer (B) (50) in this order, said structure (a) (200) further including an electronic component (70) that is fixedly adhered to the epoxy resin layer (10), and a support substrate (80) that is attached to the adhesive resin layer (B) (50); a step (C) for sealing the electronic component (70) with a sealing material (60); and a step (D) for obtaining a structure (b) (300) provided with an insulating resin layer (20) that is obtained by curing the epoxy resin layer (10) and an electronic component 70 that is fixedly adhered to the insulating resin layer (20) and sealed with the sealing material (60), wherein the epoxy resin content in the epoxy resin layer (10) is 10 parts by mass or more where the total content of resin components in the epoxy resin layer (10) is 100 parts by mass.

Description

Manufacturing method of electronic device

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

[0002] Fan-out WLP (Wafer Level Packaging) has been developed as a technology that can reduce the size and weight of electronic devices (e.g., semiconductor devices). One method for fabricating fan-out WLP, called eWLB (Embedded Wafer Level Ball Grid Array), involves temporarily fixing multiple electronic components, such as semiconductor chips, in a spaced-apart state on a temporary fixing material (e.g., an adhesive film) attached to a support substrate, and then encapsulating the multiple electronic components together with an encapsulant. Here, the temporary fixing material needs to be fixed to the electronic components and the support substrate during the encapsulation process, and after encapsulation, it needs to be removed from the encapsulated electronic components together with the support substrate.

[0003] As a technique relating to a manufacturing method of such an electronic device, for example, the technique described in Patent Document 1 can be given.

[0004] Patent Document 1 describes a method for manufacturing a semiconductor package, including the steps of: placing a semiconductor chip on a semiconductor backside protective film disposed on an adhesive sheet; curing the semiconductor backside protective film after the step of placing the semiconductor chip on the semiconductor backside protective film; and encapsulating the semiconductor chip with a resin after the step of curing the semiconductor backside protective film. Patent Document 1 describes that an object of the method is to provide a method for manufacturing a semiconductor package that can prevent misalignment of the semiconductor chip due to thermal curing shrinkage of the resin.

[0005] Japanese Patent Application Laid-Open No. 2017-92335

[0006] When electronic components are placed on a temporary fixing material and then sealed with a sealing material, the positions of the electronic components may become misaligned (hereinafter, also referred to as displacement of the electronic components).

[0007] The present invention has been made in view of the above circumstances, and provides a method for manufacturing an electronic device that can suppress misalignment of electronic components.

[0008] According to the present invention, there is provided a method for manufacturing an electronic device as follows.

[0009] [1] A method for manufacturing an electronic device, comprising: a step (A) of preparing a structure (a) including a laminate including, in this order, an epoxy resin layer, a base layer, and an adhesive resin layer (B), an electronic component fixed to the epoxy resin layer, and a support substrate attached to the adhesive resin layer (B); a step (C) of encapsulating the electronic component with a sealing material; and a step (D) of obtaining a structure (b) including an insulating resin layer formed by curing the epoxy resin layer and an electronic component fixed to the insulating resin layer and encapsulated with the sealing material, wherein the content of the epoxy resin in the epoxy resin layer is 10 parts by mass or more when the total content of resin components in the epoxy resin layer is 100 parts by mass. [2] The method for manufacturing an electronic device according to [1], wherein, in the step (A), the epoxy resin layer is in an uncured state or a semi-cured state. [3] The method for manufacturing an electronic device according to [2], further comprising a step (B) of curing the epoxy resin layer between the steps (A) and (C). [4] The method for manufacturing an electronic device according to any one of [1] to [3], wherein the step (A) includes: a step (A-1) of preparing a structure (a-1) including the base layer, the adhesive resin layer (B), and the support substrate attached to the adhesive resin layer (B); and a step (A-2) of preparing a structure (a-2) in which the epoxy resin layer is attached to a surface of the structure (a-1) opposite to the support substrate side. [5] The method for manufacturing an electronic device according to any one of [1] to [4], wherein the sealing material includes an epoxy resin-based sealing material. [6] The method for manufacturing an electronic device according to any one of [1] to [5], wherein the epoxy resin layer further includes an inorganic filler. [7] The method for manufacturing an electronic device according to any one of [1] to [6], wherein the epoxy resin layer further includes a curing agent. [8] The method for manufacturing an electronic device according to any one of [1] to [7], wherein an insulating resin layer obtained by curing the epoxy resin layer is capable of forming a rewiring layer. [9] The method for manufacturing an electronic device according to any one of [1] to [8], wherein the adhesive strength of the adhesive resin layer (B) is reduced by an external stimulus.

[10] The method for manufacturing an electronic device according to [9], wherein the adhesive strength of the adhesive resin layer (B) is reduced by heating.

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

[10] , wherein the adhesive resin layer (B) contains at least one selected from the group consisting of a gas-generating component and thermally expandable microspheres.

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

[11] , wherein the laminate further includes an adhesive resin layer (A), and the adhesive resin layer (A) is located between the epoxy resin layer and the base layer.

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

[12] , wherein the total content of the gas-generating component and thermally expandable microspheres in the adhesive resin layer (A) is less than 0.1% by mass, when the entire adhesive resin layer (A) is taken as 100% by mass.

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

[12] or

[13] , wherein the adhesive resin layer (A) contains one or more selected from the group consisting of a (meth)acrylic adhesive resin, a silicone adhesive resin, a urethane adhesive resin, an olefin adhesive resin, and a styrene adhesive resin.

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

[14] , wherein the electronic device includes a fan-out package.

[0010] According to the present invention, it is possible to provide a method for manufacturing an electronic device that can suppress misalignment of electronic components.

[0011] It is a figure which showed typically an example of the manufacturing method of the electronic device of this embodiment. It is a figure which showed typically an example of the manufacturing method of the electronic device of this embodiment. It is a figure which showed typically an example of the preferable mode of step (A).

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all drawings, similar components are designated by common reference numerals, and descriptions thereof will be omitted where appropriate. Furthermore, the drawings are schematic diagrams and do not necessarily correspond to actual dimensional ratios. The expression "A to B" regarding a numerical range means A or more and B or less, unless otherwise specified. Furthermore, "(meth)acrylic" means acrylic, methacrylic, or both acrylic and methacrylic.

[0013] 1 and 2 are diagrams schematically illustrating an example of a method for manufacturing an electronic device according to the present embodiment. The method for manufacturing an electronic device according to the present embodiment includes the steps of: (A) preparing a structure (a) 200 including a laminate 100 including, in this order, an epoxy resin layer 10, a base layer 40, and an adhesive resin layer (B) 50; an electronic component 70 fixed to the epoxy resin layer 10; and a support substrate 80 attached to the adhesive resin layer (B) 50; (C) encapsulating the electronic component 70 with a sealant 60; and (D) obtaining a structure (b) 300 including an insulating resin layer 20 formed by curing the epoxy resin layer 10 and the electronic component 70 fixed to the insulating resin layer 20 and encapsulated with the sealant 60. The epoxy resin content in the epoxy resin layer 10 is 10 parts by mass or more, where the total content of the resin components in the epoxy resin layer 10 is 100 parts by mass.

[0014] As described above, a manufacturing method for an electronic device (e.g., an electronic device including a fan-out package) includes a process of temporarily fixing a plurality of electronic components, such as semiconductor chips, in a spaced-apart state on a temporary fixing material (e.g., an adhesive film, etc.) attached to a substrate, and then collectively sealing the plurality of electronic components with a sealing material. When the electronic components are placed on the temporary fixing material and sealed with a sealing material, the electronic components may become misaligned (hereinafter, also referred to as "misalignment of the electronic components"). The present inventors conducted extensive research to achieve the above-mentioned object. As a result, they discovered that, during the sealing process, the electronic components cannot withstand the pressure caused by the flow of the sealing material, resulting in misalignment of the electronic components.

[0015] A manufacturing method for an electronic device may include a step of forming a redistribution layer after encapsulating electronic components. If the electronic components are misaligned during the encapsulation step, the electronic components will be moved to a location different from their intended location during the redistribution layer formation step. Therefore, when forming the redistribution layer, misalignment of the wiring due to the misalignment of the electronic components may occur. Misalignment of the wiring may result in a decrease in the reliability of the electronic device, such as wire breakage.

[0016] In conventional techniques related to temporary fixing materials used when encapsulating electronic components with an encapsulant, for example, temporary fixing materials with high adhesive strength have been considered to eliminate misalignment of electronic components. The inventors' studies have revealed that a temporary fixing material with high adhesive strength requires a high peel force when peeling the temporary fixing material, which can result in damage to the temporary fixing material. Furthermore, it has been revealed that in the process of removing the temporary fixing material from the encapsulated electronic component together with the supporting substrate after encapsulation, a portion of the adhesive resin (hereinafter also referred to as glue) contained in the temporary fixing material can remain on the electronic component (hereinafter also referred to as glue residue). In other words, the inventors' studies have revealed that there can be a trade-off between misalignment of electronic components and glue residue.

[0017] The present inventors conducted extensive research to achieve the above object, and as a result, found that by including step (A) of preparing structure (a) 200 including electronic component 70 fixed to epoxy resin layer 10, the layer to which electronic component 70 is fixed can be made of a cured resin in the sealing step, and electronic component 70 can be fixed with a stronger force, thereby suppressing misalignment of the electronic component.

[0018] The method for manufacturing an electronic device according to this embodiment also includes a step (D) of obtaining a structure (b) 300 including an insulating resin layer 20 formed by curing an epoxy resin layer 10 and an electronic component 70 fixed to the insulating resin layer 20 and sealed with a sealing material 60. This does not include a step of peeling off the insulating resin layer 20, which is the layer that directly secures the electronic component 70, and therefore can prevent adhesive residue from remaining on the electronic component side.

[0019] Furthermore, the insulating resin layer 20 formed by curing the epoxy resin layer 10 can form the rewiring layer 30. According to the present invention, misalignment of electronic components can be suppressed, and thus misalignment of wiring due to misalignment of electronic components can be suppressed when forming the rewiring layer. Therefore, according to the present invention, the occurrence of disconnections due to misalignment of wiring can be suppressed, resulting in an electronic device with improved reliability. Here, an example of a conventional rewiring layer is a layer made of sintered polyimide. Polyimide is an expensive material. Furthermore, sintering polyimide requires a process at high temperatures (e.g., 230°C). According to the present invention, the rewiring layer can be formed inexpensively and at low temperatures.

[0020] The electronic device of this embodiment includes elements, devices, and final products to which electronic engineering technology is applied, such as semiconductor devices, power semiconductor devices, semiconductor chips, semiconductor elements, printed wiring boards, electric circuit display devices, information and communication terminals, light-emitting diodes, physical batteries, and chemical batteries. The electronic device of this embodiment preferably includes a fan-out type package. In a fan-out type package, terminals can be extended to the outside of the chip (fan out), so it can be used in applications where the number of terminals is large compared to the chip area. In addition, since a package substrate is not required, it can also be made thinner.

[0021] Each step of the method for manufacturing an electronic device according to this embodiment will be described below.

[0022] <Step (A) of Preparing Structure (a)> The method for manufacturing an electronic device of this embodiment includes step (A) of preparing structure (a) 200 including a laminate 100 including an epoxy resin layer 10, a base material layer 40, and an adhesive resin layer (B) 50 in this order, an electronic component 70 fixed to the epoxy resin layer 10, and a support substrate 80 attached to the adhesive resin layer (B) 50. Here, Figure 3 is a diagram schematically showing an example of a preferred aspect of step (A).

[0023] The laminate 100 preferably further includes an adhesive resin layer (A). The adhesive resin layer (A) is preferably located between the epoxy resin layer 10 and the base layer 40, more preferably adhered to the epoxy resin layer 10, and even more preferably adhered to both the epoxy resin layer 10 and the base layer 40.

[0024] The method for preparing the structure (a) 200 is not particularly limited, but preferably includes the steps of: (A-1) preparing a structure (a-1) 210 including a base layer 40, an adhesive resin layer (B) 50, and a support substrate 80 attached to the adhesive resin layer (B) 50; and (A-2) preparing a structure (a-2) 220 in which an epoxy resin layer 10 is attached to the surface of the structure (a-1) 210 opposite the support substrate 80 side. Here, in step (A-2), in the case of the structure (a) 200 illustrated in FIGS. 1 and 3, the surface opposite the support substrate 80 side is the base layer 40. Also, for example, when the structure (a-1) 210 further includes an adhesive resin layer (A) on the surface of the base layer 40 opposite the adhesive resin layer (B) 50 side, the surface opposite the support substrate 80 side is the adhesive resin layer (A).

[0025] In step (A-1), the structure (a-1) 210 can be produced, for example, by the following procedure. An adhesive film including a base layer 40 and an adhesive resin layer (B) 50 is attached to a support substrate 80 so that the adhesive resin layer (B) 50 side faces the support substrate 80, thereby obtaining the structure (a-1) 210. When a protective film is attached to the adhesive resin layer (B) 50 in the adhesive film, the protective film can be peeled off, and the exposed surface of the adhesive resin layer (B) 50 can be attached to the surface of the support substrate 80.

[0026] In step (A-2), the structure (a-2) 220 can be produced, for example, by the following procedure. An epoxy film containing an epoxy resin layer 10 is attached to the base layer 40 in the structure (a-1) 210 so that the epoxy resin layer 10 side faces the base layer 40, thereby obtaining the structure (a-2) 220. When the epoxy film includes a base film, a protective film, etc., the base film, the protective film, etc. may be removed as appropriate.

[0027] In addition to steps (A-1) and (A-2), step (A) of preparing structure (a) 200 preferably further includes step (A-3) of fixing electronic component 70 to epoxy resin layer 10 of structure (a-2) 220 to prepare structure (a) 200.

[0028] In the step (A), from the viewpoint of further improving the adhesion property, the epoxy resin layer 10 is preferably in an uncured state or a semi-cured state.

[0029] In step (A), the epoxy resin layer 10 may be in a cured state. When the epoxy resin layer 10 is in a cured state, the epoxy resin layer 10 can be used as the insulating resin layer 20. In other words, it can be said that the insulating resin layer 20 is formed at the stage of step (A).

[0030] The support substrate 80 may be, for example, a quartz substrate, a glass substrate, or a SUS substrate.

[0031] Examples of the electronic component 70 include semiconductor chips such as ICs, LSIs, discrete devices, light-emitting diodes, and light-receiving elements, semiconductor panels, and semiconductor packages.

[0032] <Step (B) of Curing Epoxy Resin Layer> The method for manufacturing an electronic device according to the present embodiment preferably includes step (B) of curing the epoxy resin layer 10. By curing the epoxy resin layer 10, the insulating resin layer 20 is formed. Step (B) is carried out between step (A) and step (C).

[0033] The method for curing the epoxy resin layer 10 is not particularly limited, and may be heat curing or photocuring, but heat curing is preferred.

[0034] The curing temperature when the epoxy resin layer 10 is thermally cured is not particularly limited, and may be, for example, 120° C. or higher, 140° C. or higher, 150° C. or higher, or 170° C. or higher, and may be 240° C. or lower, 220° C. or lower, or 200° C. or lower. The curing time when the epoxy resin layer 10 is thermally cured is not particularly limited, and may be, for example, 5 minutes or longer and 120 minutes or shorter.

[0035] When the epoxy resin layer 10 is thermally cured, the epoxy resin layer 10 may be preheated at a temperature lower than the curing temperature before being thermally cured.

[0036] <Step (C) of Encapsulating Electronic Components> The method for manufacturing an electronic device according to this embodiment includes step (C) of encapsulating electronic components 70 with encapsulant 60. Electronic components 70 are covered with encapsulant 60, and encapsulant 60 is cured at a temperature of, for example, 150° C. or less to encapsulate electronic components 70. The form of encapsulant 60 is not particularly limited, and may be, for example, granular, sheet-like, or liquid.

[0037] In step (C), it is preferable that the electronic component 70 is fixed to the insulating resin layer 20, since this can prevent the electronic component from being displaced.

[0038] The sealing material 60 is not particularly limited, but is preferably an epoxy resin-based sealing material using an epoxy resin. In particular, a liquid epoxy resin-based sealing material is preferred because it improves the affinity of the sealing material 60 to the epoxy resin layer 10 and enables more uniform sealing of the electronic component 70. Examples of such epoxy resin-based sealing materials that can be used include the T693 / R4000 series, T693 / R1000 series, and T693 / R5000 series manufactured by Nagase ChemteX Corporation.

[0039] Examples of the sealing method include transfer molding, injection molding, compression molding, and cast molding.

[0040] <Step (D) of Obtaining Structure (b)> The method for manufacturing an electronic device according to the present embodiment includes step (D) of obtaining structure (b) 300 including insulating resin layer 20 formed by curing epoxy resin layer 10 and electronic component 70 fixed to insulating resin layer 20 and sealed with sealing material 60. Step (D) is a step subsequent to step (C).

[0041] The structure (b) 300 includes an insulating resin layer 20 formed by curing the epoxy resin layer 10 in the temporary fixing material of the present embodiment. As described above, the method for manufacturing an electronic device of the present embodiment does not include a step of peeling the insulating resin layer 20 from the electronic component 70, and therefore, it is possible to suppress the occurrence of adhesive residue on the electronic component side.

[0042] The method for obtaining the structure (b) 300 is not particularly limited, but examples thereof include a method of mechanically peeling the insulating resin layer 20 from a layer adjacent to the insulating resin layer 20 (in the case of FIG. 1 , the base material layer 40); a method of reducing the adhesive force between the insulating resin layer 20 and the layer adjacent to the insulating resin layer 20, and then peeling the insulating resin layer 20 from the layer adjacent to the insulating resin layer 20; and the like.

[0043] As a method for obtaining the structure (b) 300, the adhesive resin layer (B) 50 may be peeled off from the support substrate 80 before peeling off the insulating resin layer 20 and the layer adjacent to the insulating resin layer 20. As a method for peeling off the adhesive resin layer (B) 50 from the support substrate 80, for example, a method in which the adhesive resin layer (B) 50 is heated to a temperature exceeding 170°C to reduce the adhesive strength of the adhesive resin layer (B) 50, and then the adhesive resin layer (B) 50 is peeled off from the support substrate 80, may be mentioned.

[0044] <Step (E) of Forming Rewiring Layer> The method for manufacturing an electronic device according to the present embodiment preferably includes step (E) of forming wiring in insulating resin layer 20 to form rewiring layer 30. Step (E) is a step subsequent to step (D).

[0045] The rewiring layer 30 can be obtained by forming wiring in the insulating resin layer 20. The method for forming wiring in the insulating resin layer 20 is not particularly limited, but an example thereof is a method in which a pattern mold is made using a photoresist and then electrolytic plating is performed to form wiring.

[0046] <Step (F) of Further Forming Redistribution Layer> The method for manufacturing an electronic device according to this embodiment preferably includes step (F) of further forming redistribution layer 90. Step (F) is a step subsequent to step (E).

[0047] The rewiring layer 90 is preferably formed on the surface of the rewiring layer 30 opposite to the side of the electronic component 70. The method for forming the rewiring layer 90 is not particularly limited, but an example thereof includes a method in which an epoxy resin layer of the same type as the epoxy resin layer 10 of the present embodiment is formed, and wiring is formed on the insulating resin layer obtained by curing the epoxy resin layer.

[0048] Furthermore, a plurality of rewiring layers may be formed by forming another rewiring layer on the surface of the rewiring layer 90 opposite to the rewiring layer 30 side.

[0049] <Other Steps> The method for manufacturing an electronic device according to this embodiment may further include a post-mold cure step, a dicing step, and the like.

[0050] [Laminate] Each layer constituting the laminate 100 in step (A) will be described.

[0051] <Epoxy Resin Layer> The epoxy resin layer 10 is a layer to which electronic components can be fixed. The epoxy resin layer 10 contains an epoxy resin. Examples of epoxy resins include bixylenol-type epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol S-type epoxy resins, bisphenol AF-type epoxy resins, dicyclopentadiene-type epoxy resins, trisphenol-type epoxy resins, naphthol novolac-type epoxy resins, phenol novolac-type epoxy resins, tert-butyl-catechol-type epoxy resins, naphthalene-type epoxy resins, naphthol-type epoxy resins, anthracene-type epoxy resins, glycidylamine-type epoxy resins, glycidyl ester-type epoxy resins, cresol novolac-type epoxy resins, biphenyl-type epoxy resins, linear aliphatic epoxy resins, epoxy resins having a butadiene structure, alicyclic epoxy resins, heterocyclic epoxy resins, spiro ring-containing epoxy resins, cyclohexanedimethanol-type epoxy resins, naphthylene ether-type epoxy resins, trimethylol-type epoxy resins, and tetraphenylethane-type epoxy resins. One type of epoxy resin may be used alone, or two or more types may be used in combination.

[0052] The content of the epoxy resin in the epoxy resin layer 10 is 10 parts by mass or more, relative to 100 parts by mass of the total content of the resin components in the epoxy resin layer 10. The content of the epoxy resin in the epoxy resin layer 10 is preferably 15 parts by mass or more, more preferably 20 parts by mass or more, even more preferably 50 parts by mass or more, relative to 100 parts by mass of the total content of the resin components in the epoxy resin layer 10, and is preferably 95 parts by mass or less, more preferably 90 parts by mass or less, even more preferably 80 parts by mass or less, and even more preferably 70 parts by mass or less.

[0053] The total content of the resin components in the epoxy resin layer 10 is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and even more preferably 20% by mass or more, from the viewpoint of further suppressing misalignment of electronic components, and is preferably 80% by mass or less, more preferably 70% by mass or less, even more preferably 50% by mass or less, even more preferably 45% by mass or less, and even more preferably 40% by mass or less, from the viewpoint of further reducing the linear expansion coefficient of the cured product of the epoxy resin layer 10.

[0054] The epoxy resin layer 10 preferably further contains an inorganic filler from the viewpoint of appropriately adjusting the linear expansion coefficient of the cured product of the epoxy resin layer 10. Examples of inorganic fillers include silica, alumina, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide, barium titanate, barium titanate zirconate, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium tungstate phosphate, with silica being preferred. One type of inorganic filler may be used alone, or two or more types may be used in combination.

[0055] Average particle diameter D of inorganic filler５０ From the viewpoint of further reducing the surface roughness of the epoxy resin layer 10, the average particle diameter D of the inorganic filler is preferably 5.0 μm or less, more preferably 2.5 μm or less, even more preferably 2.0 μm or less, and even more preferably 1.5 μm or less, and the lower limit is not particularly limited, but may be, for example, 0.01 μm or more, or 0.1 μm or more. ５０ means the particle size value at which the cumulative frequency is 50% in a volume-based cumulative frequency distribution curve measured by a laser diffraction / scattering method. Note that it is preferable to use a measurement sample in which the inorganic filler is dispersed in water by ultrasonic waves.

[0056] The inorganic filler may be surface-treated in order to improve the moisture resistance and dispersibility of the inorganic filler.

[0057] When the total content of all components in the epoxy resin layer 10 is taken as 100% by mass, the content of the inorganic filler in the epoxy resin layer 10 is preferably 20% by mass or more, more preferably 30% by mass or more, even more preferably 50% by mass or more, even more preferably 55% by mass or more, and even more preferably 60% by mass or more, from the viewpoint of further reducing the linear expansion coefficient of the cured product of the epoxy resin layer 10; and is preferably 95% by mass or less, more preferably 90% by mass or less, even more preferably 85% by mass or less, and even more preferably 80% by mass or less, from the viewpoint of further improving the mechanical strength of the epoxy resin layer 10.

[0058] The epoxy resin layer 10 preferably further contains a curing agent. The curing agent is not particularly limited as long as it is capable of curing the epoxy resin, and examples thereof include active ester-based curing agents, cyanate ester-based curing agents, phenol-based curing agents, naphthol-based curing agents, benzoxazine-based curing agents, and carbodiimide-based curing agents. One type of curing agent may be used alone, or two or more types may be used in combination.

[0059] The content of the curing agent in the epoxy resin layer 10 is not particularly limited as long as it is an amount that can cure the epoxy resin.

[0060] In addition to the components described above, the epoxy resin layer 10 may contain components such as a resin other than an epoxy resin, a curing accelerator, an organic filler, a flame retardant, and a colorant.

[0061] The epoxy resin layer 10 is preferably in an uncured state or a semi-cured state. The insulating resin layer 20 obtained by curing the epoxy resin layer 10 is preferably capable of forming the rewiring layer 30.

[0062] The insulating resin layer 20 obtained by curing the epoxy resin layer 10 has a linear expansion coefficient from 30°C to 150°C of preferably 100 ppm / K or less, more preferably 80 ppm / K or less, even more preferably 60 ppm / K or less, even more preferably 50 ppm / K or less, even more preferably 40 ppm / K or less, even more preferably 30 ppm / K or less, and even more preferably 25 ppm / K or less, from the viewpoint of further suppressing displacement of electronic components, and the lower limit is not particularly limited, but may be, for example, 5 ppm / K or more, or 10 ppm / K or more.

[0063] The glass transition temperature of the insulating resin layer 20 obtained by curing the epoxy resin layer 10 is preferably 130° C. or higher, more preferably 150° C. or higher, even more preferably 160° C. or higher, and even more preferably 170° C. or higher, from the viewpoint of further suppressing displacement of electronic components, and the upper limit is not particularly limited, but may be, for example, 200° C. or lower or 190° C. or lower. The glass transition temperature of the insulating resin layer 20 can be measured, for example, by a dynamic viscoelasticity measuring device.

[0064] The thickness of the epoxy resin layer 10 is preferably 1 μm or more, more preferably 3 μm or more, even more preferably 5 μm or more, and even more preferably 8 μm or more, and is preferably 500 μm or less, more preferably 400 μm or less, even more preferably 300 μm or less, even more preferably 250 μm or less, even more preferably 200 μm or less, even more preferably 150 μm or less, even more preferably 100 μm or less, even more preferably 70 μm or less, and even more preferably 50 μm or less.

[0065] <Substrate Layer> The substrate layer 40 is not particularly limited, but examples thereof include a resin film. Known thermoplastic resins can be used as the resin constituting the resin film. Examples include one or more selected from the group consisting of polyolefins such as polyethylene, polypropylene, poly(4-methyl-1-pentene), and poly(1-butene); polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyamides such as nylon-6, nylon-66, and polymethaxylene adipamide; polyacrylate; polymethacrylate; polyvinyl chloride; polyvinylidene chloride; polyimide; polyetherimide; ethylene-vinyl acetate copolymer; polyacrylonitrile; polycarbonate; polystyrene; ionomer; polysulfone; polyethersulfone; and polyphenylene ether. Among these, the resin constituting the resin film is preferably one or more selected from the group consisting of polypropylene, polyethylene terephthalate, polyethylene naphthalate, polyamide and polyimide, from the viewpoint of an excellent balance of transparency, mechanical strength, price, etc., and more preferably at least one selected from the group consisting of polyethylene terephthalate and polyethylene naphthalate.

[0066] The substrate layer 40 may be a single layer or two or more layers. The form of the resin film used to form the substrate layer 40 may be a stretched film or a uniaxially or biaxially stretched film, but a uniaxially or biaxially stretched film is preferred from the viewpoint of improving the mechanical strength of the substrate layer 40. The resin film may also be subjected to a surface treatment, specifically, a corona treatment, a plasma treatment, an undercoat treatment, a primer coat treatment, or the like.

[0067] The thickness of the substrate layer 40 is preferably 1 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more, and is preferably 500 μm or less, more preferably 300 μm or less, and even more preferably 250 μm or less.

[0068] <Adhesive Resin Layer (B)> The adhesive resin layer (B) 50 is a layer attached to a support substrate. From the viewpoint of easily peeling the adhesive resin layer (B) 50 from the support substrate, the adhesive strength of the adhesive resin layer (B) 50 preferably decreases with an external stimulus. Examples of adhesive resin layers (B) 50 whose adhesive strength decreases with an external stimulus include heat-peelable adhesive resin layers whose adhesive strength decreases with heating and radiation-peelable adhesive resin layers whose adhesive strength decreases with radiation. Among these, heat-peelable adhesive resin layers whose adhesive strength decreases with heating are preferred. Examples of heat-peelable adhesive resin layers include adhesive resin layers composed of a heat-expandable adhesive containing a gas-generating component, a heat-expandable adhesive containing heat-expandable microspheres that expand to reduce adhesive strength, and a heat-expandable adhesive whose adhesive strength decreases due to a crosslinking reaction of the adhesive component caused by heat. The adhesive resin layer (B) 50 preferably contains at least one selected from the group consisting of a gas-generating component and heat-expandable microspheres.

[0069] In this embodiment, the thermally expandable adhesive used in the adhesive resin layer (B) 50 is an adhesive whose adhesive strength decreases or is lost when heated at a temperature exceeding 170°C. For example, a material that does not peel at temperatures below 170°C but peels at temperatures exceeding 170°C can be selected. It is preferable that the adhesive strength is sufficient to prevent the adhesive resin layer (B) 50 from peeling from the support substrate during the manufacturing process of the electronic device. Here, the decrease or loss of adhesive strength due to heating at a temperature exceeding 170°C can be evaluated, for example, by attaching the adhesive resin layer (B) 50 side of the adhesive film to a stainless steel plate, heating it at 140°C for 1 hour, and then heating it at a temperature exceeding 170°C for 2 minutes, and then measuring the peel strength from the stainless steel plate. The specific heating temperature when heating at a temperature exceeding 170°C is set to a temperature higher than the temperature at which gas is generated and the temperature at which the heat-expandable microspheres thermally expand, and is set appropriately depending on the gas generated and the type of heat-expandable microspheres. In this embodiment, loss of adhesive strength refers to, for example, a case where the 180° peel strength measured under conditions of 23° C. and a pulling rate of 300 mm / min is less than 0.5 N / 25 mm.

[0070] Examples of gas-generating components that can be used in thermally expandable pressure-sensitive adhesives include azo compounds, azide compounds, and Meldrum's acid derivatives. Other examples include inorganic blowing agents such as ammonium carbonate, ammonium bicarbonate, sodium bicarbonate, ammonium nitrite, sodium boron hydroxide, and various azides; water; fluorinated alkane compounds such as trichloromonofluoromethane and dichloromonofluoromethane; azo compounds such as azobisisobutyronitrile, azodicarbonamide, and barium azodicarboxylate; paratoluenesulfonylhydrazide, diphenylsulfone-3,3'-disulfonylhydrazide, 4,4'-oxybis(benzenesulfonyl)hydrazide; Other examples of organic blowing agents that can be used include hydrazine compounds such as p-toluenesulfonylsemicarbazide and 4,4'-oxybis(benzenesulfonylsemicarbazide); semicarbazide compounds such as p-toluenesulfonylsemicarbazide and 4,4'-oxybis(benzenesulfonylsemicarbazide); triazole compounds such as 5-morpholyl-1,2,3,4-thiatriazole; and N-nitroso compounds such as N,N'-dinitrosopentamethylenetetramine and N,N'-dimethyl-N,N'-dinitrosoterephthalamide. The gas-generating component may be added to the adhesive resin (B1) or may be directly bonded to the adhesive resin (B1).

[0071] The heat-expandable microspheres used in the heat-expandable pressure-sensitive adhesive may be, for example, a microencapsulated blowing agent. Examples of such heat-expandable microspheres include microspheres in which a substance that readily gasifies and expands upon heating, such as isobutane, propane, or pentane, is encapsulated within an elastic shell. Examples of materials constituting the shell include vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, and polysulfone. Heat-expandable microspheres can be produced, for example, by a coacervation method or an interfacial polymerization method. Heat-expandable microspheres can be added to the adhesive resin (B1).

[0072] The content of at least one selected from the gas-generating component and the heat-expandable microspheres can be appropriately set depending on the expansion ratio and adhesive strength reduction of the heat-peelable adhesive resin layer (B) 50, and is not particularly limited, but is, for example, 1 part by mass to 150 parts by mass, preferably 10 parts by mass to 130 parts by mass, and more preferably 12 parts by mass to 100 parts by mass, per 100 parts by mass of the adhesive resin (B1) in the heat-peelable adhesive resin layer (B) 50. It is preferable to design the temperature at which gas is generated or the temperature at which the heat-expandable microspheres thermally expand are above 170°C.

[0073] Examples of the adhesive resin (B1) constituting the thermally expandable adhesive agent include (meth)acrylic adhesive resin (b), urethane adhesive resin, silicone adhesive resin, polyolefin adhesive resin, polyester adhesive resin, polyamide adhesive resin, fluorine adhesive resin, styrene-diene block copolymer adhesive resin, etc. Among these, (meth)acrylic adhesive resin (b) is preferred.

[0074] The (meth)acrylic adhesive resin (b) used in the adhesive resin layer (B) 50 may be, for example, a copolymer containing a (meth)acrylic acid alkyl ester monomer unit (b1) and a monomer unit (b2) having a functional group capable of reacting with a crosslinking agent. In this embodiment, the (meth)acrylic acid alkyl ester refers to an acrylic acid alkyl ester, a methacrylic acid alkyl ester, or a mixture thereof.

[0075] The (meth)acrylic adhesive resin (b) according to this embodiment can be obtained, for example, by copolymerizing a monomer mixture containing a (meth)acrylic acid alkyl ester monomer (b1) and a monomer (b2) having a functional group capable of reacting with a crosslinking agent.

[0076] Examples of the monomer (b1) that forms the (meth)acrylic acid alkyl ester monomer unit (b1) include (meth)acrylic acid alkyl esters having an alkyl group containing about 1 to 12 carbon atoms. (Meth)acrylic acid alkyl esters having an alkyl group containing 1 to 8 carbon atoms are preferred. Specific examples include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, and 2-ethylhexyl methacrylate. These may be used alone or in combination of two or more. In the (meth)acrylic adhesive resin (b) according to this embodiment, the content of the (meth)acrylic acid alkyl ester monomer unit (b1) is preferably 10% by mass or more and 98.9% by mass or less, more preferably 50% by mass or more and 97% by mass or less, and even more preferably 85% by mass or more and 95% by mass or less, when the total of all monomer units in the (meth)acrylic adhesive resin (b) is taken as 100% by mass.

[0077] Examples of the monomer (b2) that forms the monomer unit (b2) having a functional group reactive with a crosslinking agent include acrylic acid, methacrylic acid, itaconic acid, mesaconic acid, citraconic acid, fumaric acid, maleic acid, itaconic acid monoalkyl ester, mesaconic acid monoalkyl ester, citraconic acid monoalkyl ester, fumaric acid monoalkyl ester, maleic acid monoalkyl ester, glycidyl acrylate, glycidyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide, methacrylamide, tert-butylaminoethyl acrylate, and tert-butylaminoethyl methacrylate. Preferred are acrylic acid, methacrylic acid, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide, methacrylamide, and the like. These may be used alone or in combination of two or more. In the (meth)acrylic adhesive resin (b) according to the present embodiment, the content of the monomer unit (b2) is preferably 1% by mass or more and 40% by mass or less, more preferably 1% by mass or more and 20% by mass or less, and even more preferably 1% by mass or more and 10% by mass or less, when the total of all monomer units in the (meth)acrylic adhesive resin (b) is 100% by mass.

[0078] The (meth)acrylic adhesive resin (b) according to this embodiment may further contain, in addition to the monomer unit (b1) and the monomer unit (b2), a bifunctional monomer unit (b3) or a specific comonomer unit having surfactant properties (hereinafter referred to as a polymerizable surfactant). The polymerizable surfactant has the property of copolymerizing with the monomer (b1), the monomer (b2), and the monomer (b3), and also acts as an emulsifier when emulsion polymerization is performed.

[0079] Examples of the monomer (b3) forming the bifunctional monomer unit (b3) include allyl methacrylate, allyl acrylate, divinylbenzene, vinyl methacrylate, vinyl acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tetraethylene glycol di(meth)acrylate, and, for example, diacrylates or acrylates having both ends thereof. or dimethacrylates whose main chain structure is a propylene glycol type (for example, NOF Corporation, trade names: PDP-200, PDP-400, ADP-200, ADP-400), a tetramethylene glycol type (for example, NOF Corporation, trade names: ADT-250, ADT-850), or a mixture thereof (for example, NOF Corporation, trade names: ADET-1800, ADPT-4000).

[0080] In the (meth)acrylic adhesive resin (b) according to the present embodiment, the content of the monomer unit (b3) is preferably 0.1% by mass or more and 30% by mass or less, more preferably 0.1% by mass or more and 20% by mass or less, even more preferably 0.1% by mass or more and 15% by mass or less, and even more preferably 0.1% by mass or more and 5% by mass or less, when the total of all monomer units in the (meth)acrylic adhesive resin (b) is 100% by mass.

[0081] Examples of the polymerizable surfactant include those in which a polymerizable 1-propenyl group has been introduced into the benzene ring of polyoxyethylene nonylphenyl ether (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.; trade names: AQUALON RN-10, RN-20, RN-30, RN-50, etc.), those in which a polymerizable 1-propenyl group has been introduced into the benzene ring of an ammonium salt of a sulfate ester of polyoxyethylene nonylphenyl ether (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.; trade names: AQUALON HS-10, HS-20, HS-1025, etc.), and sulfosuccinic acid diesters having a polymerizable double bond in the molecule (manufactured by Kao Corporation; trade names: Latemul S-120A, S-180A, etc.). In the (meth)acrylic adhesive resin (b) according to the present embodiment, the content of the polymerizable surfactant is preferably 0.1% by mass or more and 30% by mass or less, more preferably 0.1% by mass or more and 20% by mass or less, even more preferably 0.1% by mass or more and 15% by mass or less, and still more preferably 0.1% by mass or more and 5% by mass or less, when the sum of all monomer units in the (meth)acrylic adhesive resin (b) is 100% by mass.

[0082] The (meth)acrylic adhesive resin (b) according to the present embodiment may further contain, as necessary, a monomer unit formed from a monomer having a polymerizable double bond, such as vinyl acetate, acrylonitrile, or styrene.

[0083] The polymerization reaction mechanism of the (meth)acrylic adhesive resin (b) according to this embodiment may be radical polymerization, anionic polymerization, cationic polymerization, or the like. Taking into consideration the production cost of the (meth)acrylic adhesive resin (b), the influence of the functional groups of the monomer, and the influence of ions on the surface of electronic components, polymerization by radical polymerization is preferred. When polymerization is carried out by radical polymerization, the radical polymerization initiator may be 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-butylperoxy-2-hexanoate, t-butyl peroxy, and the like. Examples of the peroxide include organic peroxides such as 2-ethylhexanoate, t-butylperoxy-3,5,5-trimethylhexanoate, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, t-butyl peroxide, and di-t-amyl peroxide; inorganic peroxides such as ammonium persulfate, potassium persulfate, and sodium persulfate; and azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, and 4,4'-azobis-4-cyanovaleric acid.

[0084] When polymerization is carried out by emulsion polymerization, among these radical polymerization initiators, inorganic peroxides such as water-soluble ammonium persulfate, potassium persulfate, and sodium persulfate, and azo compounds having a carboxyl group in the molecule such as water-soluble 4,4'-azobis-4-cyanovaleric acid are preferred. In consideration of the influence of ions on the surface of electronic components, azo compounds having a carboxyl group in the molecule such as ammonium persulfate and 4,4'-azobis-4-cyanovaleric acid are more preferred, and azo compounds having a carboxyl group in the molecule such as 4,4'-azobis-4-cyanovaleric acid are even more preferred.

[0085] The adhesive resin layer (B) 50 according to this embodiment preferably further contains, in addition to the adhesive resin (B1), a crosslinking agent (B2) having two or more crosslinkable functional groups per molecule. The crosslinking agent (B2) having two or more crosslinkable functional groups per molecule is reacted with the functional groups of the adhesive resin (B1) to adjust the adhesive strength and cohesive strength. Examples of such crosslinking agents (B2) include epoxy compounds such as sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, neopentyl glycol diglycidyl ether, and resorcinol diglycidyl ether; isocyanate compounds such as tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate triadduct of trimethylolpropane, polyisocyanate, diphenylmethane diisocyanate, and tolylene diisocyanate; and trimethylolpropane-tri-β-aziridinylpropionate. Examples of suitable epoxy compounds include aziridine compounds such as tetramethylolmethane-tri-β-aziridinylpropionate, N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide), N,N'-hexamethylene-1,6-bis(1-aziridinecarboxamide), N,N'-toluene-2,4-bis(1-aziridinecarboxamide), and trimethylolpropane-tri-β-(2-methylaziridine)propionate; tetrafunctional epoxy compounds such as N,N,N',N'-tetraglycidyl-m-xylylenediamine and 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane; and melamine compounds such as hexamethoxymethylolmelamine. These compounds may be used alone or in combination of two or more. Among these, it is preferable to use one or more compounds selected from epoxy compounds, isocyanate compounds, and aziridine compounds.

[0086] The content of the crosslinking agent (B2) is usually preferably within a range such that the number of functional groups in the crosslinking agent (B2) is not greater than the number of functional groups in the adhesive resin (B1). However, if necessary, an excess amount of the crosslinking agent (B2) may be added when new functional groups are generated in the crosslinking reaction or when the crosslinking reaction is slow. The content of the crosslinking agent (B2) in the adhesive resin layer (B) 50 is preferably 0.1 parts by mass or more and 10 parts by mass or less, more preferably 0.5 parts by mass or more and 5 parts by mass or less, per 100 parts by mass of the adhesive resin (B1).

[0087] From the viewpoint of improving adhesion to the support substrate, the adhesive resin layer (B) 50 according to this embodiment preferably contains a tackifier resin in addition to the adhesive resin (B1). Incorporation of a tackifier resin into the adhesive resin layer (B) 50 is preferred because it facilitates adjustment of adhesion to the support substrate at around room temperature. The tackifier resin preferably has a softening point of 100°C or higher. Specific examples of tackifier resins include rosin-based resins such as rosin derivatives treated by esterification or the like; terpene-based resins such as α-pinene, β-pinene, dipentene, and terpene phenol-based resins; natural rosins such as gum-based, wood-based, and tall oil-based resins; hydrogenated, disproportionated, dimerized (polymerized), or maleated resins of these natural rosins; petroleum resins; and coumarone-indene resins.

[0088] Among these, those having a softening point in the range of 100 to 160°C are more preferred, and those in the range of 120 to 150°C are even more preferred. Using a tackifier resin having a softening point within the above range not only reduces contamination and adhesive residue on the support substrate, but also enables improved adhesion to the support substrate in a working environment. Furthermore, using a polymerized rosin ester-based tackifier resin as the tackifier resin not only reduces contamination and adhesive residue on the support substrate, but also improves adhesion to the support substrate in an environment of 80 to 130°C, and, in the case of a heat-expandable pressure-sensitive adhesive containing heat-expandable microspheres, enables easier peeling from the support substrate after the heat-expandable microspheres have expanded.

[0089] The blending ratio of the tackifier resin is not particularly limited, and may be appropriately selected so as to adjust the elastic modulus of the adhesive resin layer (B) 50 within the desired predetermined numerical range. However, in terms of the elastic modulus and initial peel strength of the adhesive resin layer (B) 50, a blending ratio of 1 to 100 parts by mass per 100 parts by mass of the adhesive resin (B1) is preferred. When the blending ratio of the tackifier resin is equal to or greater than the lower limit per 100 parts by mass of the adhesive resin (B1), adhesion to the support substrate during operation tends to be improved. On the other hand, when the blending ratio is equal to or less than the upper limit, attachment to the support substrate at room temperature tends to be improved. In terms of adhesion to the support substrate and attachment at room temperature, a blending ratio of the tackifier resin of 2 to 50 parts by mass per 100 parts by mass of the adhesive resin (B1) is more preferred. Furthermore, the acid value of the tackifier resin is preferably 30 or less. When the acid value of the tackifier resin is equal to or less than the upper limit, adhesive residue on the support substrate tends to be less likely to be left during peeling.

[0090] The adhesive resin layer (B) 50 may contain additives such as plasticizers as other components. The total content of the adhesive resin (B1), crosslinking agent (B2), and tackifier resin in the adhesive resin layer (B) 50 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 entire adhesive resin layer (B) 50 is taken as 100% by mass. Furthermore, when the adhesive resin layer (B) 50 is composed of a heat-expandable adhesive, the total content of the adhesive resin (B1), crosslinking agent (B2), tackifier resin, gas-generating component, and heat-expandable microspheres in the adhesive resin layer (B) 50 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 entire adhesive resin layer (B) 50 is taken as 100% by mass.

[0091] The thickness of the adhesive resin layer (B) 50 is preferably 5 μm or more, more preferably 20 μm or more, and is preferably 300 μm or less, more preferably 150 μm or less.

[0092] <Adhesive Resin Layer (A)> The laminate 100 preferably further includes an adhesive resin layer (A), which is located between the epoxy resin layer 10 and the base layer 40. The provision of the adhesive resin layer (A) can improve the adhesion between the epoxy resin layer 10 and the base layer 40, thereby suppressing misalignment of the epoxy resin layer 10 in the step of encapsulating the electronic components with an encapsulant, and as a result, can further suppress misalignment of the electronic components.

[0093] The adhesive resin layer (A) contains an adhesive resin (A1). The adhesive resin (A1) preferably contains at least one or more selected from the group consisting of (meth)acrylic adhesive resins (a), silicone adhesive resins, urethane adhesive resins, olefin adhesive resins, and styrene adhesive resins, and among these, more preferably contains a (meth)acrylic adhesive resin (a) from the viewpoint of facilitating adjustment of adhesive strength.

[0094] The adhesive resin layer (A) may be a radiation-crosslinkable adhesive resin layer whose adhesive strength is reduced by radiation. The radiation-crosslinkable adhesive resin layer is crosslinked by irradiation with radiation, and its adhesive strength is significantly reduced, making it easier to peel the adhesive resin layer (A) from the epoxy resin layer 10. Examples of radiation include ultraviolet rays, electron beams, and infrared rays. The radiation-crosslinkable adhesive resin layer is preferably an ultraviolet-crosslinkable adhesive resin layer.

[0095] The (meth)acrylic adhesive resin (a) used in the adhesive resin layer (A) may be, for example, a copolymer containing a (meth)acrylic acid alkyl ester monomer unit (a1) and a monomer unit (a2) having a functional group capable of reacting with a crosslinking agent. In this embodiment, the (meth)acrylic acid alkyl ester refers to an acrylic acid alkyl ester, a methacrylic acid alkyl ester, or a mixture thereof.

[0096] The (meth)acrylic adhesive resin (a) according to this embodiment can be obtained, for example, by copolymerizing a monomer mixture containing a (meth)acrylic acid alkyl ester monomer (a1) and a monomer (a2) having a functional group capable of reacting with a crosslinking agent.

[0097] Examples of the monomer (a1) forming the (meth)acrylic acid alkyl ester monomer unit (a1) include (meth)acrylic acid alkyl esters having an alkyl group containing about 1 to 12 carbon atoms. (Meth)acrylic acid alkyl esters having an alkyl group containing 1 to 8 carbon atoms are preferred. Specific examples include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, and 2-ethylhexyl methacrylate. These may be used alone or in combination of two or more. In the (meth)acrylic adhesive resin (a) according to this embodiment, the content of the (meth)acrylic acid alkyl ester monomer unit (a1) is preferably 10% by mass or more and 98.9% by mass or less, more preferably 50% by mass or more and 97% by mass or less, and even more preferably 85% by mass or more and 95% by mass or less, when the total of all monomer units in the (meth)acrylic adhesive resin (a) is taken as 100% by mass.

[0098] Examples of the monomer (a2) that forms the monomer unit (a2) having a functional group reactive with a crosslinking agent include acrylic acid, methacrylic acid, itaconic acid, mesaconic acid, citraconic acid, fumaric acid, maleic acid, itaconic acid monoalkyl ester, mesaconic acid monoalkyl ester, citraconic acid monoalkyl ester, fumaric acid monoalkyl ester, maleic acid monoalkyl ester, glycidyl acrylate, glycidyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide, methacrylamide, tert-butylaminoethyl acrylate, and tert-butylaminoethyl methacrylate. Preferred are acrylic acid, methacrylic acid, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide, methacrylamide, and the like. These may be used alone or in combination of two or more. In the (meth)acrylic adhesive resin (a) according to the present embodiment, the content of the monomer unit (a2) is preferably 1% by mass or more and 40% by mass or less, more preferably 1% by mass or more and 20% by mass or less, and even more preferably 1% by mass or more and 10% by mass or less, when the total of all monomer units in the (meth)acrylic adhesive resin (a) is 100% by mass.

[0099] The (meth)acrylic adhesive resin (a) according to this embodiment may further contain, in addition to the monomer unit (a1) and the monomer unit (a2), a bifunctional monomer unit (a3) ​​or a specific comonomer unit having surfactant properties (hereinafter referred to as a polymerizable surfactant). The polymerizable surfactant has the property of copolymerizing with the monomer (a1), the monomer (a2), and the monomer (a3), and also acts as an emulsifier when emulsion polymerization is performed.

[0100] Examples of the monomer (a3) ​​forming the bifunctional monomer unit (a3) ​​include allyl methacrylate, allyl acrylate, divinylbenzene, vinyl methacrylate, vinyl acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tetraethylene glycol di(meth)acrylate, and, for example, diacrylates or acrylates having both ends thereof. or dimethacrylates whose main chain structure is a propylene glycol type (for example, NOF Corporation, trade names: PDP-200, PDP-400, ADP-200, ADP-400), a tetramethylene glycol type (for example, NOF Corporation, trade names: ADT-250, ADT-850), or a mixture thereof (for example, NOF Corporation, trade names: ADET-1800, ADPT-4000).

[0101] In the (meth)acrylic adhesive resin (a) according to the present embodiment, the content of the monomer unit (a3) ​​is preferably 0.1% by mass or more and 30% by mass or less, more preferably 0.1% by mass or more and 20% by mass or less, even more preferably 0.1% by mass or more and 15% by mass or less, and even more preferably 0.1% by mass or more and 5% by mass or less, when the total of all monomer units in the (meth)acrylic adhesive resin (a) is 100% by mass.

[0102] Examples of the polymerizable surfactant include those in which a polymerizable 1-propenyl group has been introduced into the benzene ring of polyoxyethylene nonylphenyl ether (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.; trade names: AQUALON RN-10, RN-20, RN-30, RN-50, etc.), those in which a polymerizable 1-propenyl group has been introduced into the benzene ring of an ammonium salt of a sulfate ester of polyoxyethylene nonylphenyl ether (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.; trade names: AQUALON HS-10, HS-20, HS-1025, etc.), and sulfosuccinic acid diesters having a polymerizable double bond in the molecule (manufactured by Kao Corporation; trade names: Latemul S-120A, S-180A, etc.). In the (meth)acrylic adhesive resin (a) according to the present embodiment, the content of the polymerizable surfactant is preferably 0.1% by mass or more and 30% by mass or less, more preferably 0.1% by mass or more and 20% by mass or less, even more preferably 0.1% by mass or more and 15% by mass or less, and still more preferably 0.1% by mass or more and 5% by mass or less, when the sum of all monomer units in the (meth)acrylic adhesive resin (a) is 100% by mass.

[0103] The (meth)acrylic adhesive resin (a) according to the present embodiment may further contain, if necessary, a monomer unit formed from a monomer having a polymerizable double bond, such as vinyl acetate, acrylonitrile, or styrene.

[0104] The polymerization reaction mechanism of the (meth)acrylic adhesive resin (a) according to this embodiment may be radical polymerization, anionic polymerization, cationic polymerization, or the like. Taking into consideration the production cost of the (meth)acrylic adhesive resin (a), the influence of the functional groups of the monomer, and the influence of ions on the surface of electronic components, polymerization by radical polymerization is preferred. When polymerization is carried out by radical polymerization, the radical polymerization initiator may be 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-butylperoxy-2-hexanoate, t-butyl peroxy, and the like. Examples of the peroxide include organic peroxides such as 2-ethylhexanoate, t-butylperoxy-3,5,5-trimethylhexanoate, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, t-butyl peroxide, and di-t-amyl peroxide; inorganic peroxides such as ammonium persulfate, potassium persulfate, and sodium persulfate; and azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, and 4,4'-azobis-4-cyanovaleric acid.

[0105] When polymerization is carried out by emulsion polymerization, among these radical polymerization initiators, inorganic peroxides such as water-soluble ammonium persulfate, potassium persulfate, and sodium persulfate, and azo compounds having a carboxyl group in the molecule such as water-soluble 4,4'-azobis-4-cyanovaleric acid are preferred. In consideration of the influence of ions on the surface of electronic components, azo compounds having a carboxyl group in the molecule such as ammonium persulfate and 4,4'-azobis-4-cyanovaleric acid are more preferred, and azo compounds having a carboxyl group in the molecule such as 4,4'-azobis-4-cyanovaleric acid are even more preferred.

[0106] The adhesive resin layer (A) according to this embodiment preferably further contains, in addition to the adhesive resin (A1), a crosslinking agent (A2) having two or more crosslinkable functional groups per molecule. The crosslinking agent (A2) having two or more crosslinkable functional groups per molecule is reacted with the functional groups of the adhesive resin (A1) to adjust the adhesive strength and cohesive strength. Examples of such crosslinking agents (A2) include epoxy compounds such as sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, neopentyl glycol diglycidyl ether, and resorcinol diglycidyl ether; isocyanate compounds such as tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate triadduct of trimethylolpropane, polyisocyanate, diphenylmethane diisocyanate, and tolylene diisocyanate; and trimethylolpropane-tri-β-aziridinylpropionate. Examples of suitable epoxy compounds include aziridine compounds such as tetramethylolmethane-tri-β-aziridinylpropionate, N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide), N,N'-hexamethylene-1,6-bis(1-aziridinecarboxamide), N,N'-toluene-2,4-bis(1-aziridinecarboxamide), and trimethylolpropane-tri-β-(2-methylaziridine)propionate; tetrafunctional epoxy compounds such as N,N,N',N'-tetraglycidyl-m-xylylenediamine and 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane; and melamine compounds such as hexamethoxymethylolmelamine. These compounds may be used alone or in combination of two or more. Among these, it is preferable to use one or more compounds selected from epoxy compounds, isocyanate compounds, and aziridine compounds.

[0107] The content of the crosslinking agent (A2) is usually preferably within a range such that the number of functional groups in the crosslinking agent (A2) is not greater than the number of functional groups in the adhesive resin (A1). However, an excess amount of the crosslinking agent (A2) may be added as necessary when new functional groups are generated in the crosslinking reaction or when the crosslinking reaction is slow. From the viewpoint of improving the balance between the heat resistance and adhesion of the adhesive resin layer (A), the content of the crosslinking agent (A2) in the adhesive resin layer (A) is preferably 0.1 parts by mass or more and 15 parts by mass or less per 100 parts by mass of the adhesive resin (A1).

[0108] The adhesive resin layer (A) may contain additives such as plasticizers and tackifying resins as other components. When the adhesive resin layer (A) is a radiation-crosslinkable adhesive resin layer, it may contain various additives for radiation crosslinking. The total content of the adhesive resin (A1) and the crosslinking agent (A2) in the adhesive resin layer (A) is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more, when the entire adhesive resin layer (A) is taken as 100% by mass. This makes it easier to obtain the structure (b).

[0109] The total content of the gas-generating component and the heat-expandable microspheres in the adhesive resin layer (A) is preferably less than 0.1% by mass, more preferably less than 0.05% by mass, even more preferably less than 0.01% by mass, and still more preferably 0.00% by mass, based on 100% by mass of the entire adhesive resin layer (A). Here, the gas-generating component and the heat-expandable microspheres refer to the same components as the gas-generating component and the heat-expandable microspheres contained in the adhesive resin layer (B) 50.

[0110] The thickness of the adhesive resin layer (A) is preferably 1 μm or more, more preferably 3 μm or more, and is preferably 100 μm or less, more preferably 50 μm or less.

[0111] <Other Layers> The laminate 100 may be provided with other layers as long as the effects of this embodiment are not impaired. Examples of such other layers include an irregularity-absorbing layer, an impact-absorbing layer, and an easy-adhesion layer. The other layers are located, for example, between the epoxy resin layer 10 and the substrate layer 40; between the substrate layer 40 and the adhesive resin layer (B) 50; between the adhesive resin layer (A) and the substrate layer 40; and the like.

[0112] The unevenness-absorbing layer is preferably formed from natural rubber or synthetic rubber, or a synthetic resin having rubber elasticity, having a Shore D hardness according to ASTM D-2240 Shore D hardness of, for example, 50 or less, preferably 40 or less. The thickness of the unevenness-absorbing layer is, for example, 500 μm or less, preferably 5 to 300 μm, and more preferably 10 to 150 μm.

[0113] Examples of synthetic rubber or synthetic resin include nitrile-based, diene-based, and acrylic-based synthetic rubbers, thermoplastic elastomers such as polyolefin-based and polyester-based, and synthetic resins having rubber elasticity such as ethylene-vinyl acetate copolymers, polyurethanes, polybutadiene, and soft polyvinyl chloride. In this embodiment, even essentially hard polymers such as polyvinyl chloride can be used that have rubber elasticity due to the addition of additives such as plasticizers and softeners. Furthermore, the adhesive resins exemplified for the adhesive resin layer (A) and the adhesive resin layer (B) 50 can also be preferably used to form the irregularity-absorbing layer.

[0114] [Temporary Fixing Material] Next, the temporary fixing material for forming the laminate 100 in step (A) will be described.

[0115] The form of the temporary fixing material of this embodiment is not particularly limited as long as it is a material that can form a laminate 100 including, in this order, an epoxy resin layer 10, a base layer 40, and an adhesive resin layer (B) 50. Examples of the temporary fixing material of this embodiment include a film set including an epoxy film including the epoxy resin layer 10 and an adhesive film including the base layer 40 and the adhesive resin layer (B) 50; a laminate film including, in this order, an epoxy resin layer 10, a base layer 40, and an adhesive resin layer (B) 50; and the like.

[0116] Hereinafter, a film set including an epoxy film including an epoxy resin layer 10 and an adhesive film including a substrate layer 40 and an adhesive resin layer (B) 50 will be specifically described.

[0117] The epoxy film of this embodiment is, for example, a film obtained by laminating a base film, an epoxy resin layer 10, and a protective film. Examples of the base film include polyethylene terephthalate film (PET film). Examples of the protective film include biaxially oriented polypropylene film (OPP film). A commercially available epoxy film may be used as the epoxy film of this embodiment, such as Ajinomoto Build-Up Film (registered trademark, manufactured by Ajinomoto Fine-Techno Co., Ltd.).

[0118] The pressure-sensitive adhesive film of this embodiment is a film in which a base layer 40 and a pressure-sensitive adhesive resin layer (B) 50 are laminated, and is preferably a film in which a pressure-sensitive adhesive resin layer (A), a base layer 40, and a pressure-sensitive adhesive resin layer (B) 50 are laminated. The pressure-sensitive adhesive film of this embodiment may be appropriately provided with a protective film or the like.

[0119] The laminated film, which is one aspect of the temporary fixing material of the present embodiment and which includes an epoxy resin layer 10, a base material layer 40, and an adhesive resin layer (B) 50 in this order, may further include a protective film or the like as appropriate.

[0120] In the epoxy film, adhesive film, and laminate film of this embodiment, preferred aspects of the epoxy resin layer 10, base layer 40, adhesive resin layer (B) 50, and adhesive resin layer (A) are the same as the preferred aspects of each layer of the laminate 100.

[0121] The method for producing the temporary fixing material of this embodiment is not particularly limited, and examples thereof include the following methods. When the temporary fixing material of this embodiment is a film set including an epoxy film containing an epoxy resin layer 10 and an adhesive film containing a base layer 40 and an adhesive resin layer (B) 50, for example, an epoxy film can be obtained by applying a resin composition for forming the epoxy resin layer 10 to the base film and drying it. Also, for example, an adhesive film can be obtained by applying an adhesive coating liquid for forming the adhesive resin layer (B) 50 to the base layer 40 and drying it. When the temporary fixing material of this embodiment is a laminate film including the epoxy resin layer 10, the base layer 40, and the adhesive resin layer (B) 50 in this order, for example, a laminate film can be obtained by bonding the base layer 40 of the adhesive film and the epoxy resin layer 10 of the epoxy film together.

[0122] 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.

[0123] The present invention is not limited to the above-described embodiment, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention.

[0124] REFERENCE SIGNS LIST 10 Epoxy resin layer 20 Insulating resin layer 30 Rewiring layer 40 Base layer 50 Adhesive resin layer (B) 60 Sealant 70 Electronic component 80 Support substrate 90 Rewiring layer 100 Laminate 200 Structure (a) 210 Structure (a-1) 220 Structure (a-2) 300 Structure (b)

Claims

1. A method for manufacturing an electronic device, comprising: a step (A) of preparing a structure (a) comprising a laminate having, in this order, an epoxy resin layer, a base layer, and an adhesive resin layer (B), an electronic component fixed to the epoxy resin layer, and a support substrate attached to the adhesive resin layer (B); a step (C) of encapsulating the electronic component with an encapsulant; and a step (D) of obtaining a structure (b) comprising an insulating resin layer formed by curing the epoxy resin layer, and an electronic component fixed to the insulating resin layer and encapsulated with the encapsulant, wherein the content of the epoxy resin in the epoxy resin layer is 10 parts by mass or more when the total content of resin components in the epoxy resin layer is 100 parts by mass.

2. The method for manufacturing an electronic device according to claim 1, wherein in step (A), the epoxy resin layer is in an uncured or semi-cured state.

3. The method for manufacturing an electronic device according to claim 2, further comprising a step (B) of curing the epoxy resin layer between the steps (A) and (C).

4. The method for manufacturing an electronic device according to any one of claims 1 to 3, wherein the step (A) includes: a step (A-1) of preparing a structure (a-1) comprising the base material layer, the adhesive resin layer (B), and the support substrate attached to the adhesive resin layer (B); and a step (A-2) of preparing a structure (a-2) in which the epoxy resin layer is attached to a surface of the structure (a-1) opposite to the support substrate side.

5. The method for manufacturing an electronic device according to any one of claims 1 to 4, wherein the sealing material includes an epoxy resin-based sealing material.

6. The method for manufacturing an electronic device according to any one of claims 1 to 5, wherein the epoxy resin layer further contains an inorganic filler.

7. The method for manufacturing an electronic device according to any one of claims 1 to 6, wherein the epoxy resin layer further contains a curing agent.

8. The method for manufacturing an electronic device according to any one of claims 1 to 7, wherein the insulating resin layer formed by curing the epoxy resin layer is capable of forming a rewiring layer.

9. The method for manufacturing an electronic device according to any one of claims 1 to 8, wherein the adhesive strength of the adhesive resin layer (B) is reduced by an external stimulus.

10. The method for manufacturing an electronic device according to claim 9, wherein the adhesive strength of the adhesive resin layer (B) is reduced by heating.

11. The method for manufacturing an electronic device according to claim 10, wherein the adhesive resin layer (B) contains at least one material selected from the group consisting of a gas-generating component and thermally expandable microspheres.

12. A method for manufacturing an electronic device according to any one of claims 1 to 11, wherein the laminate further comprises an adhesive resin layer (A), and the adhesive resin layer (A) is located between the epoxy resin layer and the base material layer.

13. The method for manufacturing an electronic device according to claim 12, wherein the total content of the gas-generating component and the heat-expandable microspheres in the adhesive resin layer (A) is less than 0.1% by mass when the entire adhesive resin layer (A) is taken as 100% by mass.

14. A method for manufacturing an electronic device as described in claim 12 or 13, wherein the adhesive resin layer (A) contains one or more types selected from the group consisting of (meth)acrylic adhesive resins, silicone adhesive resins, urethane adhesive resins, olefin adhesive resins, and styrene adhesive resins.

15. The method for manufacturing an electronic device according to any one of claims 1 to 14, wherein the electronic device comprises a fan-out type package.

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