Adhesive film and manufacturing method for electronic device

Abstract

An adhesive film (50) comprising an adhesive resin layer (B), an intermediate layer (A), and a base material layer (10) in this order, wherein the storage elastic modulus G' of the intermediate layer (A) is 4.0-50.0 kPa.

Description

Method for manufacturing adhesive film and electronic device

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

[0002] Fan-out packaging is known as a technology that can reduce the size and weight of electronic devices (e.g., semiconductor devices). One method for fabricating a fan-out package, called an embedded wafer level ball grid array (eWLB), involves temporarily fixing a plurality of electronic components, such as semiconductor chips, spaced apart on an adhesive film attached to a support substrate, and then encapsulating the plurality of electronic components together with an encapsulant. Here, the adhesive film must be adhered to the electronic components and the support substrate during the encapsulation process, and must be removed from the encapsulated electronic components together with the support substrate after encapsulation.

[0003] Techniques relating to a method for manufacturing such a fan-out type package include, for example, the technique described in Patent Document 1 (Japanese Patent Laid-Open No. 2011-134811).

[0004] Patent Document 1 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 the encapsulant to become strongly adhesive to the chip surface, the heat-resistant adhesive sheet having a base layer and an adhesive layer, the adhesive layer having an adhesive strength to SUS304 after lamination of 0.5 N / 20 mm or more, and hardening 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] JP 2011-134811 A

[0006] According to the investigations of the present inventors, it has become clear that, for example, heating during sealing of electronic components causes the intermediate layer to flow, and wrinkles tend to form in the film. The present invention has been made in view of the above circumstances, and provides a pressure-sensitive adhesive film and a method for manufacturing an electronic device that can suppress the occurrence of wrinkles during heating.

[0007] The present inventors have conducted extensive research to achieve the above object, and as a result have found that the occurrence of wrinkles during heating can be suppressed by setting the storage modulus G' of the intermediate layer in the pressure-sensitive adhesive film after photocuring within a specific range, thereby completing the present invention.

[0008] According to the present invention, the following methods for producing a pressure-sensitive adhesive film and an electronic device are provided.

[0009] [1] An adhesive film comprising an adhesive resin layer (B), an intermediate layer (A), and a base layer in this order, wherein the storage modulus G' of the intermediate layer (A) measured by the following (Method 1) is 4.0 kPa or more and 50.0 kPa or less. (Method 1) The intermediate layers (A) are stacked to a thickness of 2 mm, and press-molded under the following conditions. The obtained press sheet is cut into a circle with a diameter of 25 mm to obtain a test piece. <Pressing conditions> Heating temperature: 100°C, preheating time: 2 minutes, main pressure load: 10 MPa, main pressure time: 2 minutes, cooling temperature: 20°C, cooling time: 3 minutes. Next, the obtained test piece was subjected to a pressure of 10,800 mJ / cm. ２The photocured specimen is then irradiated with UV light having a wavelength of 300 to 600 nm using a UV irradiator under the following conditions: 1. The photocured specimen is then set in the dynamic viscoelasticity measuring device via a 25 mm diameter parallel plate attachment, and the temperature dependence of dynamic viscoelasticity is measured under the following conditions: a heating rate of 5°C / min, a temperature range of 25°C to 120°C, an angular frequency of 6.3 rad / s, and torsion mode. From the resulting graph, the storage modulus G' of the intermediate layer (A) at 100°C is determined. [2] The pressure-sensitive adhesive film according to [1] above, wherein the intermediate layer (A) comprises one or more resins selected from the group consisting of polyolefin resins, ethylene-carboxylic anhydride copolymers, ethylene-epoxy copolymers, ethylene-(meth)acrylic acid ester copolymers, ethylene-ethylenically unsaturated acid copolymers, ethylene-vinyl ester copolymers, polystyrene resins, and (meth)acrylic resins. [3] The pressure-sensitive adhesive film according to [2], wherein the resin in the intermediate layer (A) has a melt flow rate (MFR) of 0.1 g / 10 min or more and 20 g / 10 min or less, as measured at 190°C under a load of 2160 g in accordance with JIS K7210:1999. [4] The pressure-sensitive adhesive film according to any one of [1] to [3], wherein the intermediate layer (A) contains a photoinitiator. [5] The pressure-sensitive adhesive film according to [4], wherein the photoinitiator contains one or more selected from the group consisting of benzophenone, benzophenone derivatives, thioxanthone, thioxanthone derivatives, benzoin, benzoin derivatives, α-hydroxyalkylphenones, α-aminoalkylphenols, acylphosphinoxides, alkylphenylglucoxylates, diethoxyacetophenone, oxime esters, titanocene compounds, and anthraquinone derivatives. [6] The pressure-sensitive adhesive film according to [5] above, wherein the photoinitiator comprises 4-methylbenzophenone. [7] The pressure-sensitive adhesive film according to any one of [4] to [6] above, wherein the content of the photoinitiator in the intermediate layer (A) is 0.01 parts by mass or more and 5.0 parts by mass or less, relative to 100 parts by mass of the total resin contained in the intermediate layer (A). [8] The pressure-sensitive adhesive film according to any one of [1] to [7] above, wherein the intermediate layer (A) comprises a crosslinking agent.[9] The pressure-sensitive adhesive film according to [8] above, wherein the crosslinking agent comprises one or more selected from the group consisting of divinyl aromatic compounds, cyanurate compounds, diallyl compounds, acrylate compounds, triallyl compounds, oxime compounds, and maleimide compounds.

[10] The pressure-sensitive adhesive film according to [9] above, wherein the crosslinking agent comprises triallyl isocyanurate.

[11] The pressure-sensitive adhesive film according to any one of [8] to

[10] above, wherein the content of the crosslinking agent in the intermediate layer (A) is 0.01 parts by mass or more and 5.0 parts by mass or less, relative to 100 parts by mass of the total resin contained in the intermediate layer (A).

[12] The pressure-sensitive adhesive film according to any one of [1] to

[11] above, wherein the thickness of the intermediate layer (A) is 100 μm or more and 1000 μm or less.

[13] The pressure-sensitive adhesive film according to any one of [1] to

[12] above, wherein the base layer comprises one or more selected from the group consisting of polypropylene, polyethylene terephthalate, polyethylene naphthalate, polyamide, and polyimide.

[14] The pressure-sensitive adhesive film according to any one of [1] to

[13] above, wherein the thickness of the base layer is from 10 μm to 1,000 μm.

[15] The pressure-sensitive adhesive film according to any one of [1] to

[14] above, wherein the pressure-sensitive adhesive resin layer (B) contains one or more selected from the group consisting of (meth)acrylic pressure-sensitive adhesive resins, silicone pressure-sensitive adhesive resins, urethane pressure-sensitive adhesive resins, olefin pressure-sensitive adhesive resins, and styrene pressure-sensitive adhesive resins.

[16] The pressure-sensitive adhesive film according to any one of [1] to

[15] above, wherein the total content of the gas-generating component and heat-expandable microspheres in the pressure-sensitive adhesive resin layer (B) is 0.1 mass% or less, when the entire pressure-sensitive adhesive resin layer (B) is taken as 100 mass%.

[17] The pressure-sensitive adhesive film according to any one of [1] to

[16] above, wherein the thickness of the pressure-sensitive adhesive resin layer (B) is from 1 μm to 40 μm.

[18] The pressure-sensitive adhesive film according to any one of [1] to

[17] , further comprising an adhesive resin layer (C) on the side of the base material layer opposite to the side of the intermediate layer (A).

[19] The pressure-sensitive adhesive film according to

[18] , wherein the adhesive resin layer (C) is a layer whose adhesive strength decreases in response to an external stimulus.

[20] The pressure-sensitive adhesive film according to

[19] , wherein the adhesive resin layer (C) contains a thermally expandable adhesive.

[21] The pressure-sensitive adhesive film according to

[20] above, wherein the thermally expandable pressure-sensitive adhesive is a pressure-sensitive adhesive whose adhesive strength decreases or is lost when heated at a temperature exceeding 150°C.

[22] The pressure-sensitive adhesive film according to any one of

[18] to

[21] above, further comprising an irregularity-absorbing resin layer (D) between the base layer and the pressure-sensitive adhesive resin layer (C).

[23] The pressure-sensitive adhesive film according to

[22] above, wherein the irregularity-absorbing resin layer (D) has a thickness of 10 μm or more and 1000 μm or less.

[24] The pressure-sensitive adhesive film according to any one of [1] to

[23] above, which is capable of temporarily fixing an electronic component when sealing the electronic component with a sealing material.

[25] The pressure-sensitive adhesive film according to

[24] above, wherein the electronic component has an irregularity structure.

[26] The pressure-sensitive adhesive film according to

[25] above, wherein the irregularity structure of the electronic component includes a bump electrode.

[27] The pressure-sensitive adhesive film according to

[26] above, wherein the height of the bump electrode is 50 μm or more and 500 μm or less.

[28] A method for producing an electronic device, comprising: step (a) of preparing a structure comprising the pressure-sensitive adhesive film according to any one of [1] to

[27] above and an electronic component attached to the pressure-sensitive adhesive resin layer (B) of the pressure-sensitive adhesive film; step (b) of subjecting the structure to one or more treatments selected from the group consisting of light irradiation and heat treatment; and step (c) of encapsulating the electronic component with an encapsulant.

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

[28] above, wherein the encapsulant comprises an epoxy resin-based encapsulant.

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

[28] or

[29] above, further comprising: step (d) of curing the encapsulant by treating with one or more methods selected from the group consisting of light irradiation and heat treatment after step (c).

[31] The method for manufacturing an electronic device according to the above

[30] , further comprising, after the step (d), a step (e) of peeling the adhesive film from the electronic component.

[32] The method for manufacturing an electronic device according to any one of the above

[28] to

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

[0010] According to the present invention, it is possible to provide a pressure-sensitive adhesive film capable of suppressing the occurrence of wrinkles when heated, and a method for manufacturing an electronic device.

[0011] Fig. 1 is a cross-sectional view schematically showing an example of the structure of an adhesive film according to an embodiment of the present invention. Fig. 2 is a cross-sectional view schematically showing an example of the structure of an adhesive film according to an embodiment of the present invention. Fig. 3 is a cross-sectional view schematically showing an example of the structure of an adhesive film according to an embodiment of the present invention. Fig. 4 is a cross-sectional view schematically showing an example of a method for manufacturing an electronic device according to an embodiment of the present invention.

[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. In the specification, the expression "A to B" regarding a numerical range means A or more and B or less, unless otherwise specified. For example, 1 to 5% means 1% or more and 5% or less. In the specification, "(meth)acrylic" means acrylic, methacrylic, or both acrylic and methacrylic.

[0013] <Adhesive Film> The adhesive film 50 of this embodiment will now be described. Fig. 1 is a cross-sectional view schematically showing an example of the structure of an adhesive film 50 of this embodiment according to the present invention.

[0014] As shown in FIG. 1 , the adhesive film 50 of this embodiment includes an adhesive resin layer (B), an intermediate layer (A), and a base layer 10, in this order, and the storage modulus G′ of the intermediate layer (A) measured by the following (Method 1) is 4.0 kPa or more and 50.0 kPa or less.

[0015] (Method 1) The intermediate layers (A) are stacked to a thickness of 2 mm, and press-molded under the following conditions. The obtained press sheet is cut into a circular shape with a diameter of 25 mm to prepare a test piece. <Pressing conditions> Heating temperature: 100°C, preheating time: 2 minutes, main pressure load: 10 MPa, main pressure time: 2 minutes, cooling temperature: 20°C, cooling time: 3 minutes. Next, the obtained test piece was subjected to a pressure of 10,800 mJ / cm ２The sample is photocured by irradiating it with UV light having a wavelength of 300 to 600 nm using a UV irradiator (for example, Ushio Inc., product name: UVX-02528S1AJA02) under the conditions of (a) to (c). The photocured test piece is then set in the dynamic viscoelasticity measuring device via a 25 mm diameter parallel plate attachment, and the temperature dependence of dynamic viscoelasticity is measured under the conditions of a heating rate of 5°C / min, a temperature range of 25°C to 120°C, an angular frequency of 6.3 rad / s, and torsion mode. The storage modulus G' of the intermediate layer (A) at 100°C is determined from the resulting graph.

[0016] As described above, the inventors' studies have revealed that heating during sealing of electronic components causes the intermediate layer to flow, making the film prone to wrinkles. The inventors conducted extensive research to achieve the above-mentioned object, and discovered that the occurrence of wrinkles during heating can be suppressed by setting the storage modulus G' of the intermediate layer in the pressure-sensitive adhesive film after photocuring within a specific range, thereby completing the present invention. The reason for this is unclear, but it is thought that the modulus at high temperatures serves as an indicator of the resistance of the intermediate layer to flow due to heat, and as a result, the occurrence of wrinkles during heating can be suppressed.

[0017] The storage modulus G' of the intermediate layer (A) in the adhesive film 50 of this embodiment is preferably 4.0 kPa or more and 45.0 kPa or less, more preferably 4.0 kPa or more and 30.0 kPa or less, even more preferably 4.0 kPa or more and 20.0 kPa or less, even more preferably 4.0 kPa or more and 15.0 kPa or less, and even more preferably 4.0 kPa or more and 12.0 kPa or less, from the viewpoint of further suppressing the occurrence of wrinkles when heated.

[0018] The total thickness of the adhesive film 50 of this embodiment is preferably 10 μm or more and 1500 μm or less, more preferably 20 μm or more and 1000 μm or less, from the viewpoint of the balance between mechanical properties and handling properties.

[0019] Examples of the electronic component 70 include semiconductor chips such as ICs, LSIs, discrete devices, light-emitting diodes, and light-receiving elements, semiconductor panels, semiconductor packages, and optical sensors.

[0020] The adhesive film 50 of this embodiment is preferably capable of temporarily fixing the electronic component 70 when the electronic component 70 is sealed with the sealing material 60. In this case, the electronic component 70 preferably has an uneven structure 75.

[0021] Here, the uneven structure 75 of the electronic component 70 preferably includes a bump electrode. When the uneven structure 75 of the electronic component 70 includes a bump electrode, where the height of the bump electrode is H [μm] and the thickness of the intermediate layer (A) is d [μm], H / d is preferably 1 or less, more preferably 0.85 or less, and even more preferably 0.7 or less. When H / d is equal to or less than the above upper limit, the thickness of the pressure-sensitive adhesive film 50 can be made thinner while improving the unevenness absorbency. The lower limit of H / d is not particularly limited, but is, for example, 0.01 or more.

[0022] When the electronic component 70 of this embodiment includes a bump electrode, the height of the bump electrode is preferably 50 μm or more and 500 μm or less, more preferably 75 μm or more and 450 μm or less, and even more preferably 100 μm or more and 400 μm or less, from the viewpoint of achieving better unevenness absorption.

[0023] Next, each layer constituting the adhesive film 50 of this embodiment will be described.

[0024] [Base layer] The base layer 10 is a layer provided for the purpose of improving the properties such as handleability, mechanical properties, and heat resistance of the pressure-sensitive adhesive film 50. The base layer 10 is not particularly limited, but examples thereof include a resin film.

[0025] The substrate layer 10 preferably contains a thermoplastic resin. The thermoplastic resin constituting the substrate layer 10 of this embodiment preferably contains one or more selected from 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; polyphenylene ether, and the like. Among these, from the viewpoint of an excellent balance of transparency, mechanical strength, price, and the like, the substrate layer 10 preferably contains one or more selected from polypropylene, polyethylene terephthalate, polyethylene naphthalate, polyamide, and polyimide, and more preferably contains one or more selected from polyethylene terephthalate and polyethylene naphthalate.

[0026] The base layer 10 may be a single layer or two or more layers. The resin film used to form the base layer 10 may be a stretched film or a uniaxially or biaxially stretched film, but from the viewpoint of improving the mechanical strength of the base layer 10, a uniaxially or biaxially stretched film is preferred.

[0027] From the viewpoint of obtaining good film properties, the thickness of the substrate layer 10 is preferably 10 μm or more and 1000 μm or less, more preferably 20 μm or more and 500 μm or less, and even more preferably 30 μm or more and 100 μm or less. The substrate layer 10 may be subjected to a surface treatment to improve adhesion to other layers. Specifically, corona treatment, plasma treatment, undercoat treatment, primer coating treatment, etc. may be performed.

[0028] [Intermediate layer (A)] The intermediate layer (A) is a layer provided on one side of the base layer 10, and is a layer that imparts to the adhesive film 50 the ability to conform to and adhere to the surface of the electronic component 70 on which the uneven structure 75 is formed, for example.

[0029] The thickness of the intermediate layer (A) in this embodiment is preferably 100 μm or more and 1000 μm or less, more preferably 150 μm or more and 750 μm or less, even more preferably 200 μm or more and 600 μm or less, and even more preferably 250 μm or more and 500 μm or less, from the viewpoint of suppressing the occurrence of wrinkles when heated while improving the performance balance of the conformability and adhesion of the adhesive film 50 to the surface on which the uneven structure 75 of the electronic component 70 is formed.

[0030] The intermediate layer (A) of this embodiment preferably contains a resin, a photoinitiator, and a crosslinking agent, from the viewpoint of suppressing the occurrence of wrinkles when heated while improving the performance balance of the conformability and adhesion of the adhesive film 50 to the surface on which the uneven structure 75 of the electronic component 70 is formed.

[0031] (Resin) From the viewpoint of being able to improve the performance balance of the conformability and adhesion of the adhesive film 50 to the surface of the electronic component 70 on which the uneven structure 75 is formed while suppressing the occurrence of wrinkles during heating, the intermediate layer (A) of the present embodiment preferably contains one or more resins selected from the group consisting of polyolefin resins, ethylene-carboxylic anhydride copolymers, ethylene-epoxy copolymers, ethylene-(meth)acrylic acid ester copolymers, ethylene-ethylenically unsaturated acid copolymers, ethylene-vinyl ester copolymers, polystyrene resins, and (meth)acrylic resins, and from the viewpoint of being able to improve the performance balance of the conformability and adhesion of the adhesive film 50 to the surface of the electronic component 70 on which the uneven structure 75 is formed, and the work efficiency during production, the intermediate layer (A) more preferably contains an ethylene-vinyl ester copolymer, and even more preferably contains an ethylene-vinyl acetate copolymer.

[0032] The ethylene-vinyl acetate copolymer is a copolymer of ethylene and vinyl acetate, for example, a random copolymer. The content of structural units derived from vinyl acetate in the ethylene-vinyl acetate copolymer is preferably 5% by mass or more and 50% by mass or less, more preferably 10% by mass or more and 45% by mass or less, and even more preferably 15% by mass or more and 40% by mass or less, when the total structural units in the ethylene-vinyl acetate copolymer are taken as 100% by mass. When the vinyl acetate content is within this range, the adhesive film 50 has a better balance of flexibility, heat resistance, transparency, and mechanical properties. The vinyl acetate content can be measured in accordance with JIS K7192:1999.

[0033] The ethylene-vinyl acetate copolymer is preferably a binary copolymer consisting of only ethylene and vinyl acetate, but may also contain, in addition to ethylene and vinyl acetate, one or more copolymerization components selected from, for example, vinyl ester monomers such as vinyl formate, vinyl glycolate, vinyl propionate, vinyl benzoate, etc.; acrylic monomers such as acrylic acid, methacrylic acid, ethacrylic acid, or salts or alkyl esters thereof; etc. When copolymerization components other than the above ethylene and vinyl acetate are contained, the amount of the copolymerization components other than ethylene and vinyl acetate in the ethylene-vinyl acetate copolymer is preferably 0.5% by mass or more and 5% by mass or less.

[0034] The melt flow rate (MFR) of the resin in the intermediate layer (A) of this embodiment, measured under conditions of 190°C and a load of 2160 g in accordance with JIS K7210:1999, is preferably 0.1 g / 10 min or more and 20 g / 10 min or less, more preferably 0.5 g / 10 min or more and 19 g / 10 min or less, even more preferably 1.0 g / 10 min or more and 18 g / 10 min or less, even more preferably 5.0 g / 10 min or more and 17 g / 10 min or less, and even more preferably 10 g / 10 min or more and 16 g / 10 min or less, from the viewpoint of being able to improve the performance balance of the conformability and adhesion of the adhesive film 50 to the surface on which the concave-convex structure 75 of the electronic component 70 is formed, while suppressing the occurrence of wrinkles and uneven thickness of the chip during heating.

[0035] The content of the resin in the intermediate layer (A) of this embodiment, when the total amount of all components contained in the intermediate layer (A) is taken as 100% by mass, is preferably 90% by mass or more and 100% by mass or less, more preferably 92% by mass or more and 100% by mass or less, even more preferably 94% by mass or more and 100% by mass or less, even more preferably 96% by mass or more and 100% by mass or less, and even more preferably 97% by mass or more and 100% by mass or less.

[0036] (Photoinitiator) The intermediate layer (A) of this embodiment preferably contains a photoinitiator, from the viewpoint of further improving the performance balance of the conformability and adhesion of the adhesive film 50 to the surface on which the uneven structure 75 of the electronic component 70 is formed, while suppressing the occurrence of wrinkles when heated.

[0037] From the viewpoint of further improving the performance balance of the conformability and adhesion of the adhesive film 50 to the surface of the electronic component 70 on which the uneven structure 75 is formed while suppressing the occurrence of wrinkles during heating, the photoinitiator of the present embodiment preferably contains one or more selected from the group consisting of benzophenone, benzophenone derivatives, thioxanthone, thioxanthone derivatives, benzoin, benzoin derivatives, α-hydroxyalkylphenones, α-aminoalkylphenols, acylphosphinoxides, alkylphenylglucoxylates, diethoxyacetophenone, oxime esters, titanocene compounds, and anthraquinone derivatives, more preferably contains one or two or more selected from the group consisting of benzophenone, benzophenone derivatives, and anthraquinone derivatives, and even more preferably contains one or two or more selected from the group consisting of benzophenone and benzophenone derivatives.

[0038] The benzophenone and benzophenone derivative of the present embodiment preferably includes one or more selected from the group consisting of benzophenone, 4-phenylbenzophenone, 4-phenoxybenzophenone, 4,4-bis(diethylamino)benzophenone, methyl o-benzoylbenzoate, 4-methylbenzophenone, and 2,4,6-trimethylbenzophenone. Among these, the photoinitiator of the present embodiment more preferably includes 4-methylbenzophenone, from the viewpoint of further improving the performance balance of the conformability and adhesion of the PSA film 50 to the surface of the electronic component 70 on which the concave-convex structure 75 is formed, while suppressing the occurrence of wrinkles during heating.

[0039] The anthraquinone derivative of the present embodiment preferably includes one or more selected from the group consisting of 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, and 1-chloroanthraquinone.

[0040] In this embodiment, the content of the photoinitiator in the intermediate layer (A) is preferably 0.01 parts by mass or more and 5.0 parts by mass or less, more preferably 0.05 parts by mass or more and 4.0 parts by mass or less, even more preferably 0.10 parts by mass or more and 3.0 parts by mass or less, even more preferably 0.30 parts by mass or more and 2.0 parts by mass or less, and even more preferably 0.40 parts by mass or more and 1.5 parts by mass or less, when the total resin contained in the intermediate layer (A) is taken as 100 parts by mass, from the viewpoint of further improving the performance balance of the conformability and adhesion of the adhesive film 50 to the surface on which the uneven structure 75 of the electronic component 70 is formed while suppressing the occurrence of wrinkles when heated.

[0041] (Crosslinking agent) The intermediate layer (A) of this embodiment preferably contains a crosslinking agent, from the viewpoint of further improving the performance balance of the conformability and adhesion of the adhesive film 50 to the surface on which the uneven structure 75 of the electronic component 70 is formed, while suppressing the occurrence of wrinkles when heated.

[0042] The crosslinking agent of the present embodiment preferably contains one or more compounds selected from the group consisting of divinyl aromatic compounds, cyanurate compounds, diallyl compounds, acrylate compounds, triallyl compounds, oxime compounds and maleimide compounds, from the viewpoint of being able to further improve the performance balance of the conformability and adhesion of the adhesive film 50 to the surface of the electronic component 70 on which the uneven structure 75 is formed, while suppressing the occurrence of wrinkles during heating, and more preferably contains a cyanurate compound.

[0043] The divinylaromatic compound of this embodiment preferably includes one or more compounds selected from the group consisting of divinylbenzene and di-i-propenylbenzene. The cyanurate compound of this embodiment preferably includes one or more compounds selected from the group consisting of triallyl cyanurate and triallyl isocyanurate. The diallyl compound of this embodiment preferably includes diallyl phthalate. The triallyl compound of this embodiment preferably includes pentaerythritol triallyl ether. The acrylate compound of this embodiment preferably includes one or more compounds selected from the group consisting of diethylene glycol diacrylate, triethylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, and tetramethylolmethane tetra(meth)acrylate. The oxime compound of this embodiment preferably includes one or more compounds selected from the group consisting of p-quinonedioxime and p-p'-dibenzoylquinonedioxime. The maleimide compound of this embodiment preferably includes m-phenylenedimaleimide.

[0044] Among these, the crosslinking agent of the present embodiment preferably contains one or more selected from the group consisting of triallyl cyanurate, triallyl isocyanurate, trimethylolpropane tri(meth)acrylate, and ditrimethylolpropane tetra(meth)acrylate, from the viewpoint of further improving the performance balance of the conformability and adhesion of the adhesive film 50 to the surface of the electronic component 70 on which the uneven structure 75 is formed, while suppressing the occurrence of wrinkles during heating, more preferably contains one or more selected from the group consisting of triallyl cyanurate and triallyl isocyanurate, and even more preferably contains triallyl isocyanurate.

[0045] In this embodiment, the content of the crosslinking agent in the intermediate layer (A) is preferably 0.01 parts by mass or more and 5.0 parts by mass or less, more preferably 0.05 parts by mass or more and 4.0 parts by mass or less, even more preferably 0.10 parts by mass or more and 3.0 parts by mass or less, even more preferably 0.30 parts by mass or more and 2.0 parts by mass or less, and even more preferably 0.40 parts by mass or more and 1.5 parts by mass or less, when the total resin contained in the intermediate layer (A) is taken as 100 parts by mass, from the viewpoint of further improving the performance balance of the conformability and adhesion of the adhesive film 50 to the surface on which the uneven structure 75 of the electronic component 70 is formed while suppressing the occurrence of wrinkles when heated.

[0046] [Adhesive Resin Layer (B)] The adhesive film 50 of the present embodiment includes an adhesive resin layer (B) on the side of the intermediate layer (A) opposite to the side of the base material layer 10. The adhesive resin layer (B) is a layer that comes into contact with the surface of the electronic component 70 to temporarily fix the electronic component 70 when the electronic component 70 is sealed with the sealing material 60 in the manufacturing process of the electronic device, for example.

[0047] The adhesive resin layer (B) preferably contains an adhesive resin (Ba). The adhesive resin (Ba) preferably contains one or more selected from the group consisting of a (meth)acrylic adhesive resin (b), a silicone adhesive resin, a urethane adhesive resin, an olefin adhesive resin, and a styrene adhesive resin. Among these, the adhesive resin (Ba) preferably contains a (meth)acrylic adhesive resin (b) from the viewpoint of improving the balance of performance between bump absorbency and adhesive strength.

[0048] The adhesive resin layer (B) may be a radiation-crosslinkable adhesive resin layer whose adhesive strength can be reduced by radiation. When the radiation-crosslinkable adhesive resin layer is irradiated with radiation, crosslinking occurs, significantly reducing the adhesive strength, making it easier to peel the adhesive film 50 from the electronic component 70. Examples of radiation include ultraviolet light, electron beams, and infrared light. The radiation-crosslinkable adhesive resin layer preferably includes an ultraviolet-crosslinkable adhesive resin layer.

[0049] The (meth)acrylic adhesive resin (b) used in the adhesive resin layer (B) of this embodiment preferably comprises a copolymer containing (meth)acrylic acid alkyl ester monomer units (b1) and monomer units (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.

[0050] The (meth)acrylic adhesive resin (b) of this embodiment can be obtained, for example, by copolymerizing a monomer mixture containing a (meth)acrylic acid alkyl ester monomer and a monomer having a functional group capable of reacting with a crosslinking agent.

[0051] The (meth)acrylic acid alkyl ester monomer of this embodiment preferably includes a (meth)acrylic acid alkyl ester having an alkyl group having about 1 to 12 carbon atoms, and more preferably includes a (meth)acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms. The (meth)acrylic acid alkyl ester having an alkyl group having about 1 to 12 carbon atoms preferably includes one or more selected from the group consisting of methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, and 2-ethylhexyl methacrylate. In the (meth)acrylic adhesive resin (b) of 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.

[0052] Preferred examples of the monomer having a functional group reactive with the crosslinking agent of this embodiment include acrylic acid, methacrylic acid, itaconic acid, mesaconic acid, citraconic acid, fumaric acid, maleic acid, monoalkyl itaconic acid esters, monoalkyl mesaconic acid esters, monoalkyl citraconic acid esters, monoalkyl fumaric acid esters, monoalkyl maleic acid esters, glycidyl acrylate, glycidyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide, methacrylamide, tert-butylaminoethyl acrylate, tert-butylaminoethyl methacrylate, etc. More preferred examples of the monomer having a functional group reactive with the crosslinking agent of this embodiment include one or more selected from the group consisting of acrylic acid, methacrylic acid, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide, and methacrylamide. In the (meth)acrylic adhesive resin (b) of the present embodiment, the content of the monomer unit (b2) having a functional group capable of reacting with a crosslinking agent 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.

[0053] The (meth)acrylic adhesive resin (b) of this embodiment may further contain, in addition to the (meth)acrylic acid alkyl ester monomer unit (b1) and the monomer unit (b2) having a functional group reactive with a crosslinking agent, 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 (meth)acrylic acid alkyl ester monomer, the monomer having a functional group reactive with a crosslinking agent, and the bifunctional monomer, and also acts as an emulsifier when emulsion polymerization is performed.

[0054] The bifunctional monomer of the present embodiment preferably includes one or more monomers selected from the group consisting of 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, monomers having diacrylate or dimethacrylate at both ends and a propylene glycol main chain structure (e.g., manufactured by NOF Corporation, trade names: PDP-200, PDP-400, ADP-200, ADP-400), tetramethylene glycol monomers (e.g., manufactured by NOF Corporation, trade names: ADT-250, ADT-850), and mixtures thereof (e.g., manufactured by NOF Corporation, trade names: ADET-1800, ADPT-4000).

[0055] In the (meth)acrylic adhesive resin (b) of the present embodiment, the content of the bifunctional 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 still 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.

[0056] The polymerizable surfactant of this embodiment preferably includes one or more surfactants selected from the group consisting of polyoxyethylene nonylphenyl ether having a polymerizable 1-propenyl group introduced into the benzene ring (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.; trade names: AQUALON RN-10, RN-20, RN-30, RN-50, etc.), polyoxyethylene nonylphenyl ether sulfate ammonium salt having a polymerizable 1-propenyl group introduced into the benzene ring (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) of 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.

[0057] The (meth)acrylic adhesive resin (b) of 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.

[0058] The polymerization reaction mechanism of the (meth)acrylic adhesive resin (b) of this embodiment may be radical polymerization, anionic polymerization, cationic polymerization, or the like. Considering the production cost of the (meth)acrylic adhesive resin (b), the influence of the functional groups of the monomers, and the influence of ions on the surface of electronic components, polymerization by radical polymerization is preferred. When polymerization by radical polymerization is performed, the (meth)acrylic adhesive resin (b) of this embodiment preferably contains a radical polymerization initiator. The radical polymerization initiator of this embodiment is preferably 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, or t-butylperoxy-2-ethylhexanoate. The peroxides may include one or more compounds selected from the group consisting of organic peroxides such as 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.

[0059] When polymerized by emulsion polymerization, the (meth)acrylic adhesive resin (b) of this embodiment preferably contains one or more compounds selected from the group consisting of water-soluble inorganic peroxides such as 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. Furthermore, in consideration of the influence of ions on the surface of electronic components, the (meth)acrylic adhesive resin (b) more preferably contains an azo compound having a carboxyl group in the molecule, such as ammonium persulfate or 4,4'-azobis-4-cyanovaleric acid, and even more preferably contains an azo compound having a carboxyl group in the molecule, such as 4,4'-azobis-4-cyanovaleric acid.

[0060] From the viewpoint of improving the balance between bump absorbency and adhesive strength, the adhesive resin layer (B) of this embodiment preferably further contains, in addition to the adhesive resin (Ba), a crosslinking agent (Bb) having two or more crosslinkable functional groups per molecule. The crosslinking agent (Bb) having two or more crosslinkable functional groups per molecule can be reacted with the functional groups of the adhesive resin (Ba) to adjust the adhesive strength and cohesive strength. The crosslinking agent (Bb) of this embodiment is preferably an epoxy-based crosslinking agent such as sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, neopentyl glycol diglycidyl ether, or resorcinol diglycidyl ether; an isocyanate-based crosslinking agent such as tetramethylene diisocyanate, hexamethylene diisocyanate, a toluene diisocyanate triadduct of trimethylolpropane, polyisocyanate, diphenylmethane diisocyanate, or tolylene diisocyanate; trimethylolpropane-tri-β-aziridinyl propionate, tetramethylolpropane-tri-β-aziridinyl propionate, or tetramethylolpropane-tri-β-aziridinyl propionate; The crosslinking agent may comprise one or more crosslinkers selected from the group consisting of aziridine-based crosslinkers such as tyrolmethane-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-based crosslinkers such as N,N,N',N'-tetraglycidyl-m-xylylenediamine and 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane; and melamine-based crosslinkers such as hexamethoxymethylolmelamine. Among these, the crosslinking agent (Bb) of the present embodiment preferably includes 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 bump absorption and adhesive strength.

[0061] The content of the crosslinking agent (Bb) is usually preferably within a range such that the number of functional groups in the crosslinking agent (Bb) is not greater than the number of functional groups in the adhesive resin (Ba). However, if new functional groups are generated by the crosslinking reaction or if the crosslinking reaction is slow, an excess amount of the crosslinking agent (Bb) may be added as necessary. The content of the crosslinking agent (Bb) in the adhesive resin layer (B) 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 (Ba) in order to improve the performance balance of the adhesive resin layer (B) in terms of bump absorption, heat resistance, and adhesion.

[0062] The adhesive resin layer (B) may contain additives such as plasticizers and tackifying resins as other components. When the adhesive resin layer (B) is a radiation-crosslinkable adhesive resin layer, it may contain various additives for radiation crosslinking. The total content of the adhesive resin (Ba) and the crosslinking agent (Bb) in the adhesive resin layer (B) is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more, based on 100% by mass of the entire adhesive resin layer (B), from the viewpoint of improving bump absorption while further suppressing the occurrence of wrinkles during heating. Furthermore, the upper limit of the total content of the adhesive resin (Ba) and the crosslinking agent (Bb) in the adhesive resin layer (B) is not particularly limited, but may be, for example, 100% by mass or less.

[0063] In the pressure-sensitive adhesive film 50 of the present embodiment, from the viewpoint of being able to stably hold the electronic component 70 on the pressure-sensitive adhesive resin layer (B) when the support substrate is peeled off from the pressure-sensitive adhesive film 50, the total content of the gas-generating component and heat-expandable microspheres in the pressure-sensitive 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, based on 100% by mass of the entire pressure-sensitive adhesive resin layer (B). It is even more preferable that the pressure-sensitive adhesive resin layer (B) does not contain any gas-generating component or heat-expandable microspheres.

[0064] The adhesive resin layer (B) may be a single layer or a multilayer. The thickness of the adhesive resin layer (B) is preferably 1 μm or more and 40 μm or less, more preferably 3 μm or more and 35 μm or less, and even more preferably 5 μm or more and 30 μm or less.

[0065] The adhesive resin layer (B) can be formed, for example, by applying an adhesive onto the intermediate layer (A) laminated on the base layer 10. 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. Among these, an aqueous emulsion coating liquid is preferred. Examples of aqueous emulsion coating liquids include coating liquids in which a (meth)acrylic adhesive resin (b), a silicone adhesive resin, a urethane adhesive resin, an olefin adhesive resin, a styrene adhesive resin, or the like is dispersed in water. An adhesive coating liquid dissolved in an organic solvent may also be used. The organic solvent is not particularly limited and may be appropriately selected from known solvents taking into account solubility and drying time. The organic solvent of the present embodiment preferably includes one or more selected from the group consisting of esters such as ethyl acetate and methyl acetate; ketones such as acetone and MEK; aromatics such as benzene, toluene, and ethylbenzene; linear or cyclic aliphatic solvents such as heptane, hexane, and cyclohexane; and alcohols such as isopropanol and butanol, and more preferably includes one or two selected from the group consisting of ethyl acetate and toluene.

[0066] The adhesive coating liquid can be applied using conventional coating methods such as a roll coater method, a reverse roll coater method, a gravure roll method, a bar coater method, a comma coater method, or a die coater method. The drying conditions for the applied adhesive are not particularly limited, but generally, drying is preferably performed for 10 seconds to 10 minutes at a temperature range of 80 to 200°C. Drying for 15 seconds to 5 minutes at 80 to 170°C is even more preferable. To sufficiently promote the crosslinking reaction between the crosslinker and the adhesive, the adhesive coating liquid may be heated at 40 to 80°C for approximately 5 to 300 hours after drying is complete.

[0067] The adhesive resin layer (B) of this embodiment may be formed by co-extrusion molding the base material layer 10 and the intermediate layer (A) together, or may be formed by further laminating a film-like adhesive resin layer (B) on the film-like intermediate layer (A) that is laminated on the film-like base material layer 10. In the examples described later, the adhesive resin layer (B) is first formed on the surface of a separator (release film), and then the adhesive resin layer (B) is bonded to another layer to produce an adhesive film.

[0068] [Adhesive Resin Layer (C)] The adhesive film 50 of the present embodiment preferably further includes an adhesive resin layer (C) on the side opposite to the intermediate layer (A) of the base material layer 10, as shown in FIG. 2, from the viewpoint of being able to fix the adhesive film 50 to a support substrate when sealing the electronic component 70 fixed to the adhesive film 50.

[0069] The adhesive resin layer (C) is preferably a layer whose adhesive strength decreases in response to an external stimulus, thereby enabling the adhesive film 50 to be peeled from the support substrate by the external stimulus. The external stimulus preferably includes one or more selected from the group consisting of light irradiation and heat treatment, and more preferably includes heat treatment.

[0070] The adhesive resin layer (C) of this embodiment preferably contains a heat-expandable adhesive from the viewpoint of further improving releasability. The heat-expandable adhesive of this embodiment preferably contains an adhesive resin (C1) and one or more components selected from the group consisting of a gas-generating component and heat-expandable microspheres, and more preferably contains an adhesive resin (C1) and heat-expandable microspheres.

[0071] The thermally expandable adhesive in the adhesive resin layer (C) of this embodiment is a layer whose adhesive strength decreases or is lost when heated at a temperature preferably above 150° C., more preferably at a temperature of 160° C. or higher, even more preferably at a temperature of 170° C. or higher, even more preferably at a temperature of 180° C. or higher, even more preferably at a temperature of 190° C. or higher, even more preferably at a temperature of 200° C. or higher, and even more preferably at a temperature of 210° C. or higher. That is, the adhesive resin layer (C) of this embodiment is a layer whose adhesive strength decreases or is lost when heated at a temperature preferably above 150° C., more preferably at a temperature of 160° C. or higher, even more preferably at a temperature of 170° C. or higher, even more preferably at a temperature of 180° C. or higher, even more preferably at a temperature of 190° C. or higher, even more preferably at a temperature of 200° C. or higher, and even more preferably at a temperature of 210° C. or higher. Such an adhesive resin layer (C) can be obtained by selecting the type of gas-generating component or heat-expandable microspheres in the adhesive resin layer (C). Here, the decrease or loss of adhesive strength due to heating at a temperature exceeding 150°C can be evaluated, for example, by attaching the adhesive resin layer (C) side to a stainless steel plate, heating it at 120°C for 1 hour, and then heating it at a temperature exceeding 150°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 150°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 appropriately set depending on the gas generated and the type of heat-expandable microspheres. In this embodiment, loss of adhesive strength refers, for example, to a 180° peel strength of less than 0.5 N / 25 mm measured at 23°C and a tensile speed of 300 mm / min.

[0072] Examples of gas-generating components that can be used include azo compounds, azide compounds, Meldrum's acid derivatives, etc. Examples of gas-generating components 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'-oxo-2,4'-dimethylaminobenzoate, and the like; Other examples of organic blowing agents that can be used include hydrazine compounds such as bis(benzenesulfonylhydrazide) and allylbis(sulfonylhydrazide); semicarbazide compounds such as p-toluylenesulfonylsemicarbazide 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 mixed with the adhesive resin (C1) or may be directly bonded to the adhesive resin (C1).

[0073] Heat-expandable microspheres can be prepared using, for example, microencapsulated blowing agents. Examples of such heat-expandable microspheres include microspheres in which a substance that easily gasifies and expands upon heating, such as isobutane, propane, or pentane, is encapsulated in an elastic shell. Examples of materials constituting the shell include vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, and polysulfone. Heat-expandable microspheres can be produced by, for example, coacervation or interfacial polymerization.

[0074] From the viewpoint of further improving thermal peelability, the total content of the gas-generating component and heat-expandable microspheres in the adhesive resin layer (C) is preferably 1 part by mass or more, more preferably 3 parts by mass or more, even more preferably 5 parts by mass or more, even more preferably 7 parts by mass or more, even more preferably 11 parts by mass or more, even more preferably 12 parts by mass or more, even more preferably 14 parts by mass or more, and is preferably 150 parts by mass or less, more preferably 100 parts by mass or less, even more preferably 50 parts by mass or less, even more preferably 25 parts by mass or less, even more preferably 20 parts by mass or less, even more preferably 18 parts by mass or less, per 100 parts by mass of the adhesive resin (C1) in the adhesive resin layer (C). From the viewpoint of further improving thermal peelability, the total content of the gas-generating component and heat-expandable microspheres in the adhesive resin layer (C) is preferably 1 to 150 parts by mass, more preferably 3 to 150 parts by mass, even more preferably 5 to 100 parts by mass, even more preferably 7 to 50 parts by mass, even more preferably 11 to 25 parts by mass, even more preferably 12 to 20 parts by mass, and even more preferably 14 to 18 parts by mass, per 100 parts by mass of the adhesive resin (C1) in the adhesive resin layer (C). It is preferable to design the temperature at which gas is generated and the temperature at which the heat-expandable microspheres thermally expand are above 150°C.

[0075] The adhesive resin (C1) of the present embodiment preferably contains 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, and from the viewpoint of further improving releasability, it more 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-based adhesive resins, and from the viewpoint of easily adjusting the adhesive strength, it is even more preferably contains a (meth)acrylic adhesive resin.

[0076] The adhesive resin layer (C) of this embodiment preferably further contains, in addition to the adhesive resin (C1), a crosslinking agent (C2) having two or more crosslinkable functional groups per molecule. The crosslinking agent (C2) having two or more crosslinkable functional groups per molecule is used to adjust the adhesive strength and cohesive strength by reacting with the functional groups of the adhesive resin (C1). The crosslinking agent (C2) of the present embodiment is preferably an epoxy-based crosslinking agent such as sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, neopentyl glycol diglycidyl ether, or resorcinol diglycidyl ether; an isocyanate-based crosslinking agent such as tetramethylene diisocyanate, hexamethylene diisocyanate, a toluene diisocyanate triadduct of trimethylolpropane, polyisocyanate, diphenylmethane diisocyanate, or tolylene diisocyanate; trimethylolpropane-tri-β-aziridinylpropionate, tetramethylolmethane-tri-β-aziridinylpropionate, N,N'-diphenylmethane-4,4'- The adhesive composition contains one or more crosslinkers selected from the group consisting of aziridine crosslinkers such as 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 crosslinkers such as N,N,N',N'-tetraglycidyl-m-xylylenediamine and 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane; and melamine crosslinkers such as hexamethoxymethylolmelamine. From the viewpoint of further improving the performance balance between adhesive strength and releasability, the adhesive composition contains more preferably one or more crosslinkers selected from the group consisting of epoxy crosslinkers, isocyanate crosslinkers, and aziridine crosslinkers.

[0077] 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 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 and 10.0 parts by mass or less, more preferably 0.5 parts by mass or more and 8.0 parts by mass or less, even more preferably 1.0 parts by mass or more and 6.0 parts by mass or less, and even more preferably 2.0 parts by mass or more and 4.0 parts by mass or less, per 100 parts by mass of the adhesive resin (C1), from the viewpoint of further improving the performance balance of adhesive strength, peelability, and storage stability.

[0078] The adhesive resin layer (C) of this embodiment preferably contains a tackifier resin in addition to the adhesive resin (C1) from the viewpoint of further improving adhesive strength. By including a tackifier resin in the adhesive resin layer (C), it becomes easier to adjust the 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; natural rosins such as gum, wood, and tall oil; petroleum resins obtained by hydrogenating, disproportionating, polymerizing, or maleating these natural rosins; and coumarone-indene resins. The adhesive resin layer (C) of this embodiment preferably contains a tackifier resin having a softening point in the range of 100 to 160°C, more preferably in the range of 120 to 150°C.

[0079] From the viewpoint of further improving adhesion to the support substrate during operation, the content of the tackifier resin in the adhesive resin layer (C) is preferably 1 part by mass or more and 100 parts by mass or less, more preferably 2 parts by mass or more and 50 parts by mass or less, even more preferably 3 parts by mass or more and 30 parts by mass or less, and even more preferably 5 parts by mass or more and 10 parts by mass or less, relative to 100 parts by mass of the adhesive resin (C1).

[0080] The adhesive resin layer (C) may contain additives such as plasticizers as other components. The lower limit of the total content of the adhesive resin (C1), crosslinking agent (C2), tackifier resin, gas-generating component, and heat-expandable microspheres in the adhesive resin layer (C), based on 100% by mass of the entire 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. The upper limit is not particularly limited, but is, for example, 100% by mass or less.

[0081] The adhesive resin layer (C) may be a single layer or multiple layers. The thickness of the adhesive resin layer (C) is preferably 10 μm or more, more preferably 15 μm or more, even more preferably 20 μm or more, and even more preferably 25 μm or more from the viewpoint of further improving the performance balance of adhesiveness and releasability, and is preferably 100 μm or less, more preferably 80 μm or less, and even more preferably 50 μm or less from the viewpoint of improving the handleability of the adhesive film 50. 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 100 μm or less, even more preferably 20 μm or more and 80 μm or less, and even more preferably 25 μm or more and 50 μm or less from the viewpoint of further improving the performance balance of adhesiveness, releasability, and handleability of the adhesive film 50.

[0082] [Irregularity-absorbing resin layer (D)] As shown in FIG. 3, the pressure-sensitive adhesive film 50 of this embodiment preferably further comprises an irregularity-absorbing resin layer (D) between the base layer 10 and the pressure-sensitive adhesive resin layer (C).

[0083] The unevenness-absorbing resin layer (D) preferably contains a thermoplastic resin, 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.

[0084] The thickness of the irregularity-absorbing resin layer (D) is preferably 10 μm or more and 1000 μm or less, more preferably 17 μm or more and 500 μm or less, and even more preferably 15 μm or more and 100 μm or less, from the viewpoint of improving the irregularity-absorbing property of the adhesive film 50.

[0085] [Other Layers] The pressure-sensitive adhesive film 50 of this embodiment may further include, for example, an easy-adhesion layer or the like between the layers, as long as the effect of this embodiment is not impaired.

[0086] [Method for Manufacturing Electronic Device] A method for manufacturing an electronic device according to this embodiment will be described with reference to the drawings. Figures 4 and 5 are cross-sectional views schematically illustrating a method for manufacturing an electronic device according to an embodiment of the present invention. The method for manufacturing an electronic device according to this embodiment preferably includes the steps of: (a) preparing a structure 100 including an adhesive film 50 and an electronic component 70 attached to an adhesive resin layer (B) of the adhesive film 50; (b) subjecting the structure 100 to one or more treatments selected from the group consisting of light irradiation and heat treatment; and (c) sealing the electronic component 70 with a sealant 60.

[0087] First, in step (a), a structure 100 including an adhesive film 50 and an electronic component 70 attached to the adhesive resin layer (B) of the adhesive film 50 is prepared.

[0088] Such a structure 100 can be obtained by placing an electronic component 70 on the adhesive resin layer (B) of the adhesive film 50 .

[0089] The surface of the electronic component 70 has an uneven structure 75 due to, for example, the presence of electrodes. Furthermore, when mounting an electronic device on a mounting surface, the electrodes are bonded to the electrodes formed on the mounting surface to form an electrical connection between the electronic device and the mounting surface (such as the mounting surface of a printed circuit board). Examples of the electrodes include bump electrodes such as ball bumps, printed bumps, stud bumps, plated bumps, and pillar bumps. That is, the electrodes are typically convex electrodes. These bump electrodes may be used alone or in combination of two or more types. The metal species constituting the bump electrodes are not particularly limited, and examples include silver, gold, copper, tin, lead, bismuth, and alloys thereof. These metal species may be used alone or in combination of two or more types.

[0090] Here, the structure 100 preferably further comprises a support substrate attached to the adhesive resin layer (C) of the adhesive film 50 .

[0091] The structure 100 further including a support substrate can be produced, for example, by the following procedure. First, the adhesive film 50 is attached to the support substrate so that the adhesive resin layer (C) faces the support substrate. A protective film called a separator may be attached to the adhesive resin layer (C), and the protective film can be peeled off, and the exposed surface of the adhesive resin layer (C) can be attached to the surface of the support substrate. For example, a quartz substrate, a glass substrate, a SUS substrate, etc. can be used as the support substrate.

[0092] Thereafter, the electronic component 70 is placed on the adhesive resin layer (B) of the adhesive film 50 in the same manner as above, thereby obtaining the structure 100.

[0093] Next, in step (b), the structure 100 is subjected to one or more treatments selected from the group consisting of light irradiation and heat treatment. In this step, the intermediate layer (A) in the structure 100 is irradiated with light or heated to provide light energy or heat energy, thereby crosslinking the intermediate layer (A).

[0094] When the intermediate layer (A) is crosslinked by irradiating it with light in step (b), it is preferable to irradiate the intermediate layer (A) with light such as ultraviolet light. The light source used here is not particularly limited, but it is preferable to use a light source capable of irradiating ultraviolet light containing wavelength components capable of exciting the photoinitiator, and it is more preferable to use a light source capable of irradiating ultraviolet light containing components with wavelengths of less than 300 nm. Examples of such light sources include high-pressure mercury lamps, low-pressure mercury lamps, metal halide lamps, and super UV lamps. The light irradiated by the above light sources may contain components with wavelengths of 300 nm or more. In the case of ultraviolet crosslinking, for example, ultraviolet light with a dominant wavelength of 365 nm is irradiated using a high-pressure mercury lamp in an environment of 0 to 60°C, with an irradiation intensity of 10 to 350 mW / cm. ２ UV dose 100-20,000 mJ / cm ２ By irradiating the intermediate layer (A) under the conditions above, the intermediate layer (A) can be crosslinked.

[0095] When the intermediate layer (A) is crosslinked by heating in step (b), the method for crosslinking the intermediate layer (A) by heating is not limited, but preferred examples include thermal crosslinking in an oven, thermal crosslinking on a hot plate, and thermal crosslinking by infrared irradiation. In the case of thermal crosslinking, the heating temperature is, for example, 100°C to 150°C, and the heat treatment time is, for example, 10 to 180 minutes. The heating temperature preferably does not exceed the temperature at which gas is generated or the temperature at which the heat-expandable microspheres thermally expand.

[0096] Thereafter, in step (c), the electronic component 70 is sealed with the sealing material 60. The electronic component 70 is sealed by covering it with the sealing material 60. Here, when the adhesive resin layer (C) of the adhesive film 50 contains at least one selected from a gas-generating component and heat-expandable microspheres, the temperature at which the sealing material 60 is used for sealing is preferably within a range that does not exceed the temperature at which gas is generated or the temperature at which the heat-expandable microspheres thermally expand.

[0097] In the step (c) of sealing the electronic components 70 with the sealing material 60, the plurality of electronic components 70 may be sealed together or individually with the sealing material 60. As a method for individually covering the plurality of electronic components 70 with the sealing material 60, it is preferable to use one or more methods selected from the group consisting of a 3D printer method, a spray method, a screen printing method, and an inkjet method, and it is more preferable to use a 3D printer method.

[0098] As the sealing material 60, any known sealing material having high insulating properties can be used, but the sealing material 60 preferably includes an epoxy resin-based sealing material, which improves the affinity of the sealing material 60 to the adhesive film 50 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. The sealing material 60 may be solid or liquid, but is preferably liquid, from the viewpoints of enabling the sealing process to be carried out at low temperature and low pressure and further suppressing misalignment of the electronic component 70 during the sealing process.

[0099] From the viewpoint of further suppressing misalignment of the electronic component 70, the thickness of the sealing material 60 after covering the electronic component 70 is preferably 1.0 μm or more and 2000.0 μm or less, more preferably 1.5 μm or more and 2000.0 μm or less, even more preferably 5.0 μm or more and 2000.0 μm or less, even more preferably 10.0 μm or more and 1500.0 μm or less, even more preferably 30.0 μm or more and 1500.0 μm or less, even more preferably 50.0 μm or more and 1000.0 μm or less, even more preferably 100.0 μm or more and 1000.0 μm or less, even more preferably 200.0 μm or more and 500.0 μm or less, and even more preferably 300.0 μm or more and 500.0 μm or less.

[0100] The sealing temperature in the step of sealing the electronic component 70 with the sealing material 60 is preferably 10° C. or higher and 100° C. or lower, more preferably 10° C. or higher and 90° C. or lower, even more preferably 15° C. or higher and 80° C. or lower, and even more preferably 20° C. or higher and 70° C. or lower, from the viewpoint of further improving the work efficiency of the step of sealing the electronic component 70 with the sealing material 60 and further suppressing misalignment of the electronic component 70. Note that the sealing temperature in this embodiment refers to the set temperature in the device used to seal the electronic component 70.

[0101] The sealing pressure in the step of sealing the electronic component 70 with the sealing material 60 is preferably 30 kPa or more and 150 kPa or less, more preferably 50 kPa or more and 150 kPa or less, even more preferably 70 kPa or more and 130 kPa or less, and even more preferably 90 kPa or more and 110 kPa or less, from the viewpoint of improving the reliability of the electronic device while further suppressing misalignment of the electronic component 70. Furthermore, it is more preferable that the sealing pressure in the step of sealing the electronic component 70 with the sealing material 60 is normal pressure. Note that the sealing pressure in this embodiment refers to the set pressure in the device used to seal the electronic component 70.

[0102] The method for manufacturing an electronic device according to this embodiment preferably further includes, after step (c), step (d) of curing the encapsulant 60 by one or more methods selected from the group consisting of light irradiation and heat treatment. This fixes the electronic component 70 and further suppresses misalignment of the electronic component 70.

[0103] The method of curing the encapsulant 60 by light irradiation is preferably a method of crosslinking and curing the encapsulant 60 by irradiating the encapsulant 60 with light such as ultraviolet light. The light source used in this method is preferably a light source capable of irradiating ultraviolet light containing wavelength components capable of exciting a photoinitiator, and more preferably a light source capable of irradiating ultraviolet light containing components with wavelengths of less than 300 nm. The method of curing the encapsulant 60 by heat treatment is preferably a method of curing the encapsulant 60 by thermal crosslinking using an oven, thermal crosslinking using a hot plate, or thermal crosslinking using infrared radiation. In the case of thermal crosslinking, the heating temperature is, for example, 100°C or higher and 150°C or lower, and the heating time is, for example, 10 to 180 minutes. The heating temperature is preferably a temperature that does not exceed the temperature at which gas contained in the pressure-sensitive adhesive film 50 generates or the temperature at which the heat-expandable microspheres thermally expand.

[0104] The method for producing an electronic device according to the present embodiment preferably further includes, after step (d), step (e) of peeling the adhesive film 50 from the electronic component 70. This step yields the electronic device 200. Examples of methods for peeling the adhesive film 50 from the electronic component 70 include a mechanical peeling method and a method of reducing the adhesive strength of the surface of the adhesive film 50 before peeling.

[0105] (Other Steps) The method for manufacturing an electronic device of the present embodiment may further include, between steps (c) and (d), a step of reducing the adhesive strength of the adhesive resin layer (C) by heat treatment to peel off the support substrate from the structure 100. For example, after sealing the electronic component 70, the support substrate can be easily removed from the adhesive film 50 by heating it to a temperature exceeding 180°C to reduce the adhesive strength of the adhesive resin layer (C).

[0106] The adhesive film 50 of this embodiment can be preferably used to manufacture an electronic device including a fan-out package. That is, the electronic device obtained by the manufacturing method of the electronic device of this embodiment includes a fan-out package. In a fan-out package, terminals can be spread 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.

[0107] 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.

[0108] The present invention is not limited to the above-described embodiment, and any modifications and improvements that can achieve the object of the present invention are included in the present invention.

[0109] The present invention will be specifically explained below with reference to examples, but the present invention is not limited thereto.

[0110] The details of the method for producing the adhesive film are as follows.

[0111] <Raw Material Components> (Resin Emulsion 1) Using 0.5 parts by mass of ammonium peroxodisulfate as a polymerization initiator, 63 parts by mass of 2-ethylhexyl acrylate, 21 parts by mass of butyl acrylate, 9 parts by mass of methyl methacrylate, 3 parts by mass of 2-hydroxyethyl methacrylate, 2 parts by mass of methacrylic acid, 1 part by mass of acrylamide, 1 part by mass of polytetramethylene glycol diacrylate (manufactured by NOF Corporation, product name: Blemmer ADT-250), and 2 parts by mass of an aqueous solution of polyoxyethylene nonylpropenyl phenyl ether ammonium sulfate (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., product name: Aqualon HS-1025) were emulsion-polymerized in deionized water at 70°C for 8 hours. After completion of polymerization, the pH was adjusted to 7 with aqueous ammonia. As a result, a (meth)acrylic resin emulsion 1 with a solids concentration of 56.5% was obtained.

[0112] (Resin Emulsion 2) Using 0.5 parts by mass of 4,4'-azobis-4-cyanovaleric acid (manufactured by Otsuka Chemical Co., Ltd., product name: ACVA) as a polymerization initiator, 74 parts by mass of butyl acrylate, 14 parts by mass of methyl methacrylate, 9 parts by mass of 2-hydroxyethyl methacrylate, 2 parts by mass of methacrylic acid, 1 part by mass of acrylamide, and 3 parts by mass of an aqueous solution of polyoxyethylene nonylpropenylphenyl ether ammonium sulfate (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., product name: Aqualon HS-1025) were emulsion-polymerized in deionized water at 70°C for 8 hours. After completion of polymerization, the pH was adjusted to 7 with aqueous ammonia. As a result, a (meth)acrylic resin emulsion 2 with a solids concentration of 42.5% was obtained.

[0113] (Resin solution 1) 49 parts by mass of ethyl acrylate, 20 parts by mass of 2-ethylhexyl acrylate, 21 parts by mass of methyl acrylate, 10 parts by mass of glycidyl methacrylate, and 0.5 parts by mass (solids content equivalent) of a benzoyl peroxide-based polymerization initiator as a polymerization initiator were reacted in 65 parts by mass of toluene and 50 parts by mass of ethyl acetate at 80° C. for 10 hours. After completion of the reaction, the resulting solution was cooled, and 25 parts by mass of xylene, 5 parts by mass of acrylic acid, and 0.5 parts by mass of tetradecyldimethylbenzylammonium chloride were added to the cooled solution, and the mixture was reacted at 85° C. for 32 hours while blowing air in, to obtain a (meth)acrylic resin solution (resin solution 1) with a solids concentration of 45% by mass.

[0114] (Main Resins) Main Resin 1: Ethylene-vinyl acetate copolymer (manufactured by Mitsui-Dow Polychemicals, product name: Evaflex (registered trademark) V523, vinyl acetate content: 20 mass%, density: 960 kg / m ３ , melt flow rate (190°C): 15 g / 10 min) Main resin 2: ethylene-vinyl acetate copolymer (manufactured by Mitsui-Dow Polychemicals, product name: Evaflex (registered trademark) EV150, vinyl acetate content: 33 mass%, density: 960 kg / m ３, melt flow rate (190°C): 30 g / 10 min) (Crosslinking agent) Crosslinking agent 1: cyanurate compound (manufactured by Mitsubishi Chemical Corporation, triallyl isocyanurate, product name: TAIC (trademark)) (Photoinitiator) Photoinitiator 1: benzophenone derivative (manufactured by SHUANG-BANG INDUSTRIAL Co., Ltd., 4-methylbenzophenone, product name: SB-PI712)

[0115] (Resin composition A for forming intermediate layer (A)) Each component was mixed using a tumbler mixer in the amounts (unit: parts by mass) shown in Table 1 to prepare resin composition A for each example and comparative example.

[0116] (Adhesive coating liquid B1 for forming adhesive resin layer (B)) 100 parts by mass of resin emulsion 1, 0.4 parts by mass of dimethylethanolamine, 5 parts by mass of an epoxy compound (manufactured by Nagase ChemteX Corporation, product name: EX-1610) as a crosslinking agent, 13 parts by mass of diethylene glycol monobutyl ether, and ２ 20 parts by mass of PEG-1000 was mixed with PEG-1000 to prepare a pressure-sensitive adhesive coating solution B1.

[0117] (Adhesive coating liquid B2 for forming adhesive resin layer (B)) 100 parts by mass of resin emulsion 2, 0.4 parts by mass of dimethylethanolamine, 5 parts by mass of an epoxy compound (manufactured by Nagase ChemteX Corporation, product name: EX-1610) as a crosslinking agent, 13 parts by mass of diethylene glycol monobutyl ether, and ２ 20 parts by mass of O were mixed to prepare a pressure-sensitive adhesive coating solution B2.

[0118] (Adhesive Coating Liquid C for Forming Adhesive Resin Layer (C)) 100 parts by mass of resin solution 1, 2.4 parts by mass of a polymerized rosin ester tackifier (manufactured by Arakawa Chemical Industries, Ltd., product name: Pencel D-125) (5.3 parts by mass per 100 parts by mass of adhesive resin, converted into solids), 1.3 parts by mass of an isocyanate crosslinking agent (manufactured by Mitsui Chemicals, Inc., product name: Olester P49-75S) (2.9 parts by mass per 100 parts by mass of adhesive resin, converted into solids), and 7.1 parts by mass of heat-expandable microspheres (manufactured by Sekisui Chemical Co., Ltd., product name: Advancell EM-503) (15.8 parts by mass per 100 parts by mass of adhesive resin, converted into solids), were mixed, and 37 parts by mass of toluene and 37 parts by mass of ethyl acetate were added to prepare adhesive coating liquid C.

[0119] <Preparation of Adhesive Film> First, resin composition A was molded using a single-screw extruder to form a resin film A having a thickness of 350 μm. This resin film A was bonded to the first surface of a polyethylene terephthalate film (manufactured by Toray Industries, Inc., product name: Lumirror S10, thickness: 38 μm, double-sided corona-treated product) serving as a substrate layer. This resulted in an intermediate layer (A). Then, adhesive coating liquid C was applied to a separator treated with silicone release and dried at 100 ° C. for 3 minutes to form a resin film C having a thickness of 27 μm. This resin film C was then bonded to the second surface of the substrate layer (the surface opposite to the surface on which the intermediate layer (A) was provided) to form an adhesive resin layer (C). Similarly, adhesive coating liquid B1 or B2 was applied to a separator and dried at 120 ° C. for 3 minutes to form a resin film B having a thickness of 6 μm. This resin film B was laminated to the intermediate layer (A). This resulted in an adhesive resin layer (B). The adhesive coating liquids used in each Example and Comparative Example are as shown in Table 1. As a result, an adhesive film having an adhesive resin layer (C), a substrate layer, an intermediate layer (A), and an adhesive resin layer (B) in this order was obtained. The obtained adhesive film was heated at 60°C for 5 days.

[0120] <Evaluation> (1) Storage modulus G' of intermediate layer after photocuring The intermediate layers (A) obtained in each example and each comparative example were stacked to a thickness of 2 mm, and press-molded under the following conditions. The obtained press sheet was cut into a circular shape with a diameter of 25 mm to prepare a test piece. <Pressing conditions> Heating temperature: 100°C, preheating time: 2 minutes, main pressure load: 10 MPa, main pressure time: 2 minutes, cooling temperature: 20°C, cooling time: 3 minutes. Next, the obtained test piece was subjected to a storage modulus G' of 10,800 mJ / cm. ２ The specimen was photocured by irradiating it with UV light having a wavelength of 300 to 600 nm using a UV irradiator (Ushio Inc., product name: UVX-02528S1AJA02) under the conditions of 100°C to 120°C. The photocured specimen was then set in the dynamic viscoelasticity measuring device via a 25 mm diameter parallel plate attachment, and the temperature dependence of dynamic viscoelasticity was measured under the conditions of a heating rate of 5°C / min, a temperature range of 25°C to 120°C, an angular frequency of 6.3 rad / s, and torsion mode. The storage modulus G' of the intermediate layer (A) at 100°C was determined from the resulting graph. The results are shown in Table 1.

[0121] (2) Evaluation of mold wrinkles The adhesive resin layer (C) side of the adhesive film (10 cm long x 10 cm wide) obtained in each Example and Comparative Example was adhered to a stainless steel plate. Then, a 10800 mJ / cm ２ The intermediate layer (A) was irradiated with UV rays having a wavelength of 300 to 600 nm using a UV irradiator (Ushio Inc., product name: UVX-02528S1AJA02) under the conditions of: In this case, UV rays were irradiated from the adhesive resin layer (B) side to crosslink (cure) the intermediate layer (A).

[0122] Next, 20 g of a liquid epoxy resin-based encapsulant (product name: R4212-2C, manufactured by Nagase ChemteX Corporation) was placed on the center of the adhesive resin layer (B), and mold molding was performed using a small press machine with a circular mold cut out of a mold with a diameter of 8 cm and a thickness of 2 mm under conditions of a curing pressure of 10 MPa and a curing temperature of 120°C. After molding, the cured epoxy resin-based encapsulant was peeled off from the adhesive film. The surface irregularities of the obtained cured epoxy resin-based encapsulant were observed on the surface that had been in contact with the tape using a shape analysis laser microscope (product name: VK-X1000, manufactured by KEYENCE Corporation), and mold wrinkles were evaluated according to the following criteria. The results are shown in Table 1. A: Repeated irregularities with a height difference between the recessed and protruding portions of 0 μm or more and less than 5 μm, or no irregularities occurred. B: Repeated irregularities with a height difference between the recessed and protruding portions of 5 μm or more occurred.

[0123] (3) Evaluation of Chip Thickness Variation First, the adhesive resin layer (C) side of the adhesive film obtained in each Example and Comparative Example was adhered to a slide glass measuring 76 mm long x 26 mm wide x 1 mm thick. Next, a 3.5 mm x 3.5 mm patterned silicon chip was used as an electronic component. Using a pickup mounter, the electronic component was attached to the adhesive resin layer (B) of the adhesive film under the following conditions: mounting pressure: 2 N (per chip area), mounting time: 1 second, and mounting temperature: 75°C, to obtain a structure. After mounting, the area around the chip of the obtained structure was observed using an optical microscope (Olympus, MX61L), and the chip thickness variation was evaluated according to the following criteria. The results are shown in Table 1. A: No shadow due to thickness variation was observed around the chip. B: Shadow due to thickness variation was observed around the chip.

[0124] (4) Bump Absorption Using a protective tape application device (DR3000II manufactured by Nitto Seiki Co., Ltd.), the adhesive resin layer (B) side of the adhesive film obtained in each Example and Comparative Example was applied to an 8-inch bump wafer (solder bump, bump height: 140 μm, bump diameter: 230 μm, bump pitch: 360 μm) (table temperature: 75° C., laminating pressure: 0.4 MPa, laminating speed: 2 mm / s). The obtained wafer with the adhesive film applied was observed with an optical microscope (MX61L manufactured by Olympus Corporation), and the bump absorption diameter of the adhesive film was measured from the area where lifting was observed using the image measurement mode, and the bump absorption was evaluated according to the following criteria. The results are shown in Table 1. A: Bump absorption diameter less than 300 μm B: Bump absorption diameter 300 μm or more

[0125]

[0126] As in each example, when the storage modulus G' of the intermediate layer in the adhesive film after photocuring was within a specific range, the occurrence of wrinkles during heating could be suppressed.

[0127] This application claims priority based on Japanese Patent Application No. 2024-043485, filed March 19, 2024, the disclosure of which is incorporated herein in its entirety by reference.

[0128] A Intermediate layer B Adhesive resin layer C Adhesive resin layer D Irregularity-absorbing resin layer 10 Base layer 50 Adhesive film 60 Sealing material 70 Electronic component 75 Irregularity structure 100 Structure 200 Electronic device

Claims

1. An adhesive film comprising an adhesive resin layer (B), an intermediate layer (A), and a base layer in this order, wherein the storage modulus G' of the intermediate layer (A) measured by the following (Method 1) is 4.0 kPa or more and 50.0 kPa or less. (Method 1) The intermediate layers (A) are stacked to a thickness of 2 mm, and press-molded under the following conditions. The obtained press sheet is cut into a circle with a diameter of 25 mm to prepare a test piece. <Pressing conditions> Heating temperature: 100°C, preheating time: 2 minutes Main pressure load: 10 MPa, main pressure time: 2 minutes Cooling temperature: 20°C, cooling time: 3 minutes Next, the obtained test piece is subjected to a pressure of 10,800 mJ / cm ２ The test piece is then photocured by irradiating it with UV light having a wavelength of 300 to 600 nm using a UV irradiator under the conditions of (1). Then, using a dynamic viscoelasticity measuring device, the photocured test piece is set in the dynamic viscoelasticity measuring device via a parallel plate attachment having a diameter of 25 mm, and the temperature dependence of dynamic viscoelasticity is measured under the conditions of a heating rate of 5°C / min, a temperature range of 25°C to 120°C, an angular frequency of 6.3 rad / s, and a torsion mode. The storage modulus G' of the intermediate layer (A) at 100°C is determined from the resulting graph.

2. The adhesive film according to claim 1, wherein the intermediate layer (A) comprises one or more resins selected from the group consisting of polyolefin resins, ethylene-carboxylic anhydride copolymers, ethylene-epoxy copolymers, ethylene-(meth)acrylic acid ester copolymers, ethylene-ethylenically unsaturated acid copolymers, ethylene-vinyl ester copolymers, polystyrene resins, and (meth)acrylic resins.

3. An adhesive film as described in claim 2, wherein the melt flow rate (MFR) of the resin in the intermediate layer (A) measured in accordance with JIS K7210:1999 at 190°C and a load of 2160 g is 0.1 g / 10 min or more and 20 g / 10 min or less.

4. The adhesive film according to any one of claims 1 to 3, wherein the intermediate layer (A) contains a photoinitiator.

5. The adhesive film according to claim 4, wherein the photoinitiator comprises one or more selected from the group consisting of benzophenone, benzophenone derivatives, thioxanthone, thioxanthone derivatives, benzoin, benzoin derivatives, α-hydroxyalkylphenones, α-aminoalkylphenols, acylphosphinoxides, alkylphenylglucoxylates, diethoxyacetophenone, oxime esters, titanocene compounds, and anthraquinone derivatives.

6. The adhesive film of claim 5, wherein the photoinitiator comprises 4-methylbenzophenone.

7. An adhesive film according to any one of claims 4 to 6, wherein the content of the photoinitiator in the intermediate layer (A) is 0.01 parts by mass or more and 5.0 parts by mass or less, when the total resin contained in the intermediate layer (A) is 100 parts by mass.

8. The adhesive film according to any one of claims 1 to 7, wherein the intermediate layer (A) contains a crosslinking agent.

9. The adhesive film according to claim 8, wherein the crosslinking agent comprises one or more compounds selected from the group consisting of divinyl aromatic compounds, cyanurate compounds, diallyl compounds, acrylate compounds, triallyl compounds, oxime compounds and maleimide compounds.

10. The adhesive film of claim 9, wherein the crosslinking agent comprises triallyl isocyanurate.

11. An adhesive film according to any one of claims 8 to 10, wherein the content of the crosslinking agent in the intermediate layer (A) is 0.01 parts by mass or more and 5.0 parts by mass or less, when the total amount of resin contained in the intermediate layer (A) is 100 parts by mass.

12. The pressure-sensitive adhesive film according to any one of claims 1 to 11, wherein the thickness of the intermediate layer (A) is 100 μm or more and 1000 μm or less.

13. The pressure-sensitive adhesive film according to any one of claims 1 to 12, wherein the base layer comprises one or more materials selected from the group consisting of polypropylene, polyethylene terephthalate, polyethylene naphthalate, polyamide, and polyimide.

14. The adhesive film according to any one of claims 1 to 13, wherein the thickness of the substrate layer is 10 μm or more and 1000 μm or less.

15. An adhesive film according to any one of claims 1 to 14, wherein the adhesive resin layer (B) contains one or more resins selected from the group consisting of (meth)acrylic adhesive resins, silicone adhesive resins, urethane adhesive resins, olefin adhesive resins, and styrene adhesive resins.

16. The adhesive film according to any one of claims 1 to 15, wherein the total content of the gas-generating component and heat-expandable microspheres in the adhesive resin layer (B) is 0.1 mass% or less, when the entire adhesive resin layer (B) is taken as 100 mass%.

17. The adhesive film according to any one of claims 1 to 16, wherein the thickness of the adhesive resin layer (B) is 1 μm or more and 40 μm or less.

18. An adhesive film according to any one of claims 1 to 17, further comprising an adhesive resin layer (C) on the side of the substrate layer opposite to the side of the intermediate layer (A).

19. The adhesive film according to claim 18, wherein the adhesive resin layer (C) is a layer whose adhesive strength decreases in response to an external stimulus.

20. The adhesive film according to claim 19, wherein the adhesive resin layer (C) contains a heat-expandable adhesive.

21. The adhesive film according to claim 20, wherein the thermally expandable adhesive is an adhesive whose adhesive strength is reduced or lost when heated at a temperature exceeding 150°C.

22. The adhesive film according to any one of claims 18 to 21, further comprising an irregularity-absorbing resin layer (D) between the substrate layer and the adhesive resin layer (C).

23. The adhesive film according to claim 22, wherein the thickness of the irregularity-absorbing resin layer (D) is 10 μm or more and 1000 μm or less.

24. An adhesive film according to any one of claims 1 to 23, which is capable of temporarily fixing electronic components when the electronic components are sealed with a sealing material.

25. The adhesive film according to claim 24, wherein the electronic component has a concave-convex structure.

26. The adhesive film according to claim 25, wherein the uneven structure of the electronic component includes a bump electrode.

27. The adhesive film according to claim 26, wherein the height of the bump electrodes is 50 μm or more and 500 μm or less.

28. A method for manufacturing an electronic device, comprising: (a) a step of preparing a structure comprising the adhesive film according to any one of claims 1 to 27 and an electronic component attached to the adhesive resin layer (B) of the adhesive film; (b) a step of subjecting the structure to one or more treatments selected from the group consisting of light irradiation and heat treatment; and (c) a step of sealing the electronic component with a sealing material.

29. The method for manufacturing an electronic device according to claim 28, wherein the encapsulant comprises an epoxy resin-based encapsulant.

30. A method for manufacturing an electronic device according to claim 28 or 29, further comprising, after step (c), step (d) of curing the sealing material by treating it with one or more methods selected from the group consisting of light irradiation and heat treatment.

31. The method for manufacturing an electronic device according to claim 30, further comprising, after step (d), a step (e) of peeling the adhesive film from the electronic component.

32. The method for manufacturing an electronic device according to any one of claims 28 to 31, wherein the electronic device comprises a fan-out package.

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