TWI904352B - Thermosetting resin composition, dry film, cured material, printed circuit board and electical and electronic component - Google Patents

Abstract

Objection: the present invention provides a thermosetting resin composition which can easily separate the wafers into single ones after the step of sealing a plurality of wafers at one time with the thermosetting resin composition and then separating the wafers one by one in the manufacture of SAW filter. Means: the thermosetting resin composition of the present invention comprises a thermosetting resin, which is characterized in that after heating the thermosetting resin composition at 100° C for 30 minutes, and further heating at 180° C for 60 minutes to cure, thereby obtaining a cured material. The cured material satisfies the following conditions: (i) The breaking point strength is below 100 MPa; (ii) a coefficient of linear expansion is below 35 ppm/°C; and (iii) Storage elastic modulus at 30°C is 2 GPa or more.

Description

Thermosetting resin compositions, dry films, cured products, printed circuit boards and electrical and electronic components

This invention relates to a thermosetting resin composition. Furthermore, this invention relates to a dry film having a resin layer formed from a dried coating of the thermosetting resin composition, a cured product of the thermosetting resin composition, a printed circuit board, and electrical and electronic components.

The sealing of chip-type devices (chip elements) such as semiconductor components and electronic components has traditionally been achieved through methods such as transfer molding using powdered epoxy resin compositions, canning using liquid epoxy resin compositions or polysiloxane resins, dispense methods, and printing methods. However, for the assembly of high-integration devices and for the efficient manufacture of surface acoustic wave (SAW) devices or crystal devices that require a hollow interior after sealing, it is now necessary to perform one-time sealing and encapsulation on a substrate containing multiple chip-type devices.

For example, Patent 1 discloses a thermosetting resin composition as a one-time sealing component, characterized by comprising (A) a cross-linked elastomer, (B) an epoxy resin, (C) an epoxy resin hardener, and (D) an inorganic filler. [Prior Art Documents]

[Patent Document 1] Japanese Patent Application Publication No. 2015-166403

[The problem the invention aims to solve]

Furthermore, in the manufacturing process of SAW filters in surface acoustic wave (SAW) devices, there is a step of sealing multiple wafers as described above in one go using a thermosetting resin composition and then monolithically wafering them one by one. The inventors of this invention have encountered the following problem: when monolithically wafering, if the hardened material formed by the thermosetting resin composition is too hard and difficult to cut, or if it thermally expands or warps, it is difficult to monolithically wafer.

Therefore, the purpose of this invention is to provide a thermosetting resin composition that, in the manufacturing of SAW filters, allows for easy monolithization of chips after sealing multiple chips at once using the thermosetting resin composition.

Furthermore, another object of the present invention is to provide a dry film using the thermosetting resin composition, a cured product of the thermosetting resin composition or dry film, a printed circuit board having such cured products, and an electrical and electronic component having the printed circuit board. [Means for Solving the Problem]

The thermosetting resin composition of the present invention contains a thermosetting resin, characterized in that the thermosetting resin composition is heated at 100°C for 30 minutes and then heated at 180°C for 60 minutes to harden it to obtain a cured product, which satisfies the following conditions: (i) the fracture strength is 100 MPa or less; (ii) the coefficient of linear expansion is 35 ppm/°C or less; and (iii) the storage elasticity at 30°C is 2 GPa or more.

In this embodiment of the invention, the thermosetting resin composition preferably further contains a hardener and an inorganic filler.

In this invention, the content of the inorganic filler, converted in terms of solid content, is preferably more than 50% by mass of the total thermosetting resin composition.

In this invention, the thermosetting resin is preferably an epoxy compound.

In this invention, the hardener is preferably selected from at least one of phenolic resins and imidazoles.

Another aspect of the dry film of the present invention is characterized by having a first film and a resin layer formed on the first film, wherein the resin layer is formed by a dried coating of the above-mentioned thermosetting resin composition.

Another type of cured material of the present invention is characterized by being obtained by curing the thermosetting resin composition or by curing the resin layer of the aforementioned dry film.

Another aspect of the present invention is a printed circuit board characterized by having the hardened material.

Another aspect of the present invention is an electrical and electronic component characterized by having the printed circuit board. [Effects of the Invention]

According to the present invention, a thermosetting resin composition can be provided, which, in the manufacturing of SAW filters, facilitates easy monolithization of wafers in the step of sealing multiple wafers at once using the thermosetting resin composition and then monolithizing the wafers one by one. Furthermore, in another embodiment of the present invention, a dry film using the thermosetting resin composition, a cured product of the thermosetting resin composition or dry film, a printed circuit board having such cured products, and an electrical and electronic component having the printed circuit board can be provided.

(Thermosetting Resin Composition) The thermosetting resin composition of this invention is heated at 100°C for 30 minutes, and then at 180°C for 60 minutes to harden it, resulting in a cured product that satisfies the following conditions (i) to (iii). In this invention, the cured product used to measure the following conditions (i) to (iii) refers to a product obtained by applying the thermosetting resin composition to a substrate in a manner that makes the cured film thickness 100 μm, placing it in a box furnace adjusted to 100°C in a hot air circulating drying oven, removing it after 30 minutes, immediately placing it in a box furnace adjusted to 180°C, removing it after 60 minutes, and allowing it to harden. The inventors of this case, through in-depth research, discovered that by satisfying conditions (i) to (iii) of the aforementioned cured material, a thermosetting resin composition can be provided. In the manufacturing of SAW filters, this composition facilitates easy monolithization of the wafers during the step of sealing multiple wafers at once with the thermosetting resin composition and then monolithizing each wafer individually. While the reasoning may not be entirely clear, it is hypothesized that the wafer monolithization is achieved by adjusting the degree of fragility, thermal expansion, and warping of the cured material formed by the thermosetting resin composition, thus achieving a suitable state. Therefore, it is hypothesized that by optimizing the fracture strength (indicating the fragility of the hardened material), the coefficient of thermal expansion (indicating the degree of thermal expansion resistance), and the storage elasticity (indicating the degree of warpage resistance), wafer monolithization can be easily achieved. However, this is merely a hypothesis and is not necessarily limited to this.

Condition (i) is that the fracture point strength is 100 MPa or less. Preferably, the fracture point strength is 30 MPa to 100 MPa, and more preferably 35 MPa to 95 MPa. It has been found that if the fracture point strength is within the above range, the wafer can be easily monolithically assembled. Furthermore, in this invention, the fracture point strength is a value obtained by measuring a hardened material with dimensions of 70 mm × 5 mm × 100 ± 5 μm (thickness) using a tensile testing machine (Shimadzu Corporation, EZ-SX) under the following measurement conditions: (Measurement Conditions) Tension speed: 1 mm/min Measurement temperature: 23°C Clamping distance: 50 mm

Condition (ii) is that the coefficient of linear expansion is 35 ppm/°C or less. Preferably, the coefficient of linear expansion is 3 ppm/°C or more and 35 ppm/°C or less, more preferably 4 ppm/°C or more and 33 ppm/°C or less. It has been found that if the coefficient of linear expansion is within the above range, the wafer can be easily monolithically assembled. Furthermore, in this invention, the coefficient of linear expansion is the average coefficient of linear expansion at 30~100°C obtained by measuring a hardened material with dimensions of 15mm × 3mm × 100±5μm (thickness) using a TMA measuring device (TA Instruments, Q400EM) under the following measurement conditions. (Measurement Conditions) 1st: Temperature increase from 30°C to 300°C at 10°C/min 2nd: Temperature decrease from 300°C to 30°C at 10°C/min 3rd: Temperature increase from 30°C to 300°C at 10°C/min

Condition (iii) requires a storage elasticity of 2 GPa or higher at 30°C. Preferably, the storage elasticity at 30°C is 3 GPa or higher and 10 GPa or lower, more preferably 5 GPa or higher and 10 GPa or lower. It has been found that if the storage elasticity at 30°C is within the above-mentioned range, wafer monolithization can be easily achieved. Furthermore, in this invention, the storage elasticity at 30°C is a value calculated using a DMA measuring device (Hitachi High-Tech Science Corporation, DMA7100) under the following measurement conditions, by measuring a hardened material with dimensions of 30 mm × 5 mm × 100 ± 5 μm (thickness). (Measurement Conditions) Measurement Temperature: 30~300°C Heating Rate: 5°C/min Loading Gap: 10 min Frequency: 1Hz Axial Force: 0.05N

The thermosetting resin composition that satisfies conditions (i) to (iii) above contains a thermosetting resin, preferably further containing a hardener and an inorganic filler, and may also contain other components. The thermosetting resin composition can satisfy conditions (i) to (iii) above, for example, by appropriately adjusting the type of thermosetting resin, the amount of thermosetting resin, the type of inorganic filler, and the amount of inorganic filler. The components are described below.

(Thermosetting Resins) Thermosetting resins are readily available to those skilled in the art. By incorporating thermosetting resins into compositions, the fracture strength, coefficient of thermal expansion, and storage elasticity of the cured coating can be optimized. Examples of thermosetting resins that can be used include: melamine resins, benzoguanidine resins, melamine derivatives, benzoguanidine derivatives, and other amino resins; isocyanate compounds; terminal isocyanate compounds; cyclic carbonate compounds; epoxy compounds; oxocyclobutane compounds; episulfide resins; bismaleimide; and carbodiimide resins. Of these, those having multiple cyclic ether groups or cyclic thioether groups (hereinafter referred to as cyclic (thio)ether groups) in the molecule are preferred. Thermosetting resins may be used alone or in combination of two or more.

These thermosetting resins containing multiple cyclic (thio) ether groups are compounds containing one or both of cyclic ether groups or cyclic thioether groups with 3, 4, or 5 members. Examples include: compounds containing multiple epoxy groups, i.e., polyfunctional epoxy compounds; compounds containing multiple oxocyclic butyl groups, i.e., polyfunctional oxocyclic butane compounds; and compounds containing multiple thioether groups, i.e., cyclic sulfide resins. Among these, epoxy compounds are preferred.

Examples of epoxy compounds include: bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol E type epoxy resin, bisphenol M type epoxy resin, bisphenol P type epoxy resin, bisphenol Z type epoxy resin, etc., as well as bisphenol A phenolic varnish type epoxy resin and phenolic varnish type epoxy resin. Resins, phenolic varnish epoxy resins, biphenyl-type epoxy resins, biphenyl aralkyl-type epoxy resins, aryl alkyl-type epoxy resins, tetrahydroxyphenylethane-type epoxy resins, naphthalene-type epoxy resins, onion-type epoxy resins, phenoxy-type epoxy resins, dicyclopentadiene-type epoxy resins, and norcamphene-type epoxy resins. Resins, diamond-type epoxy resins, cyclohexylmaleimide and glycidyl methacrylate copolymer epoxy resins, epoxy resins copolymerized with glycidyl methacrylate, epoxy-modified polybutadiene rubber derivatives, CTBN-modified epoxy resins, trimethylolpropane polyglycidyl ether, benzene Examples of such products include 1,3-diglycidyl ether, biphenyl-4,4'-diglycidyl ether, 1,6-hexanediol diglycidyl ether, ethylene glycol or propylene glycol diglycidyl ether, sorbitol polyglycidyl ether, triisocyanate (2,3-epoxypropyl) ester, and triisocyanate triisocyanate (2-hydroxyethyl) ester. From the perspective of optimizing the fracture point strength, coefficient of thermal expansion, and storage elasticity of the hardened coating, it is preferable to use bisphenol A type epoxy resin, dicyclopentadiene type epoxy resin, and phenolic varnish type epoxy resin; more preferably, two or more of these are used in combination; and even more preferably, three of these are used in combination.

Commercially available epoxy resins include, for example: jER 828, 806, 807, YX8000, YX8034, and 834 manufactured by Mitsubishi Chemical Co., Ltd.; YD-128, YDF-170, ZX-1059, and ST-3000 manufactured by NIPPON STEEL Chemical & Material Co., Ltd.; EPICLON 830, 835, 840, 850, N-730A, and N-695 manufactured by DIC CORPORATION; and RE-306 manufactured by Nippon Kayaku Co., Ltd.

Examples of polyfunctional oxocyclobutane compounds include: bis[(3-methyl-3-oxocyclobutane methoxy)methyl] ether, bis[(3-ethyl-3-oxocyclobutane methoxy)methyl] ether, 1,4-bis[(3-methyl-3-oxocyclobutane methoxy)methyl]benzene, 1,4-bis[(3-ethyl-3-oxocyclobutane methoxy)methyl]benzene, (3-methyl-3-oxocyclobutane)methyl acrylate, (3-ethyl-3-oxocyclobutane)methyl acrylate, and methacrylate. Multifunctional oxocyclobutanes include methyl 3-methyl-3-oxocyclobutane, methyl 3-ethyl-3-oxocyclobutane, and their oligomers or copolymers. Other examples include ethers of oxocyclobutanols with phenolic varnish resins, poly(p-hydroxystyrene), cardo-type bisphenols, calixarenes, resorcinol calixarenes, or silsesquioxanes and other resins containing hydroxyl groups. Furthermore, copolymers of unsaturated monomers with oxocyclobutane rings with alkyl (meth)acrylates are also included.

Examples of compounds containing multiple cyclic sulfide groups include bisphenol A type cyclic sulfide resins. Additionally, cyclic sulfide resins in which the oxygen atom of the epoxy group of phenolic varnish-type epoxy resin is replaced with a sulfur atom can also be synthesized using the same method.

As amine resins such as melamine derivatives and benzoguanidine derivatives, examples include: hydroxymethyl melamine compounds, hydroxymethyl benzoguanidine compounds, hydroxymethyl acetylenide compounds, and hydroxymethyl urea compounds.

Polyisocyanate compounds can also be added as isocyanate compounds. Examples of polyisocyanate compounds include: 4,4'-diphenylmethane diisocyanate, 2,4-methylenephenyl diisocyanate, 2,6-methylenephenyl diisocyanate, naphthalene-1,5-diisocyanate, ortho-methylenediisocyanate, meta-methylenediisocyanate, and aromatic polyisocyanates such as 2,4-methylenephenyl dimer; tetramethylene diisocyanate, hexamethylene... Aliphatic polyisocyanates such as diisocyanates, methylene diisocyanates, trimethylhexamethylene diisocyanates, 4,4-methylene bis(hexyl cycloisocyanate) and isophorone diisocyanates; alicyclic polyisocyanates such as dicycloheptane triisocyanate; and adducts, biuret forms and trimer isocyanates of the previously listed isocyanate compounds.

As a terminating isocyanate compound, the product of an addition reaction between an isocyanate compound and an isocyanate terminator can be used. Examples of isocyanate compounds that can react with isocyanate terminators include, for example, the aforementioned polyisocyanate compounds. Examples of isocyanate terminators include: phenolic terminators; lactamine terminators; active methylene terminators; alcohol terminators; oxime terminators; thiol terminators; acetylammine terminators; amide terminators; imidazole terminators; and imine terminators.

The amount of thermosetting resin, in terms of solid content, is preferably 3 to 40% by mass, more preferably 4 to 35% by mass, and even more preferably 5 to 30% by mass, relative to the total amount of thermosetting resin components.

(Thermoplastic Resins) To enhance the mechanical strength of the resulting cured coating, the thermoplastic resin composition may further contain thermoplastic resins. It is preferable that the thermoplastic resins are solvent-soluble. Solvent solubility improves the flexibility of the dry film, thus inhibiting cracking or powdering. Examples of thermoplastic resins include: thermoplastic polyhydroxyl polyether resins, phenoxy resins consisting of condensates of epichlorohydrin and various difunctional phenolic compounds, phenoxy resins formed by esterifying the hydroxyl groups in the hydroxyl ether portion of the backbone using various acid anhydrides or chlorohydrins, polyvinyl acetal resins, polyamide resins, polyamide-amide resins, block copolymers, and polymer resins with a glass transition temperature below 20°C and a weight average molecular weight of 10,000 or more. Among these, polymer resins with a glass transition temperature below 20°C and a weight average molecular weight of 10,000 or more are preferred. Acrylic copolymers are particularly preferred. Thermoplastic resins can be used alone or in combination with two or more.

The amount of thermoplastic resin added relative to the total amount of thermosetting resin components, in terms of solid content, is preferably 0.5 to 15% by mass, more preferably 0.5 to 10% by mass.

(Curing Agent) As a curing agent, conventional curing agents generally used for curing thermosetting resins can be used. Examples of curing agents include: phenolic resins, polycarboxylic acids and their anhydrides, cyanate ester resins, reactive ester resins, maleimide compounds, alicyclic olefin polymers, amines, imidazoles, etc. Among these, from the viewpoint of optimizing the fracture point strength, coefficient of thermal expansion, and storage elasticity of the cured coating, phenolic resins and imidazoles are preferred, with phenolic resins being more preferred. One curing agent may be used alone, or two or more may be used in combination.

As phenolic resins, those commonly known such as phenolic varnish resins, alkylphenolic varnish resins, bisphenol A phenolic varnish resins, dicyclopentadiene-type phenolic resins, Xylok-type phenolic resins, terpene-modified phenolic resins, cresol/naphthol resins, polyethylene phenols, phenol/naphthol resins, phenolic resins containing an α-naphthol skeleton, cresol phenolic varnish resins containing a triphenyl alkyl skeleton, biphenyl aralkyl-type phenolic resins, and Zyloric-type phenolic varnish resins can be used alone or in combination with two or more other types.

Among phenolic resins, those with a hydroxyl equivalent of 130 g/eq. or higher are preferred, and those with 150 g/eq. or higher are even more preferred. Examples of phenolic resins with a hydroxyl equivalent of 130 g/eq. or higher include: dicyclopentadiene skeleton phenolic varnish resins (GDP series, manufactured by Chung Jung Chemical Industry Co., Ltd.), Zyloric type phenolic varnish resins (MEH-7800, manufactured by Meiwa Chemical Co., Ltd.), biphenyl aralkyl type phenolic varnish resins (MEH-7851, manufactured by Meiwa Chemical Co., Ltd.), naphthol aralkyl type hardeners (SN series, manufactured by NIPPON STEEL Chemical & Material Co., Ltd.), and cresol phenolic varnish resins containing a trimethylolamine skeleton (LA-3018-50P, manufactured by DIC CORPORATION), etc.

Imidazoles refer to the reaction products of epoxy resins and imidazoles. Examples include: 2-methylimidazole, 4-methyl-2-ethylimidazole, 2-phenylimidazole, 4-methyl-2-phenylimidazole, 1-benzyl-2-methylimidazole, 2-ethylimidazole, 2-isopropylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecaprolimidazole, etc. Commercially available imidazole products include: 2E4MZ, C11Z, C17Z, 2PZ (these are imidazole compounds resulting from the reaction of epoxy resin and imidazole); 2MZ-A, 2E4MZ-A, 2MZA-PW (these are azine compounds of imidazole); 2MZ-OK, 2PZ-OK (these are isocyanates of imidazole); 2PHZ, 2P4MHZ (these are imidazole hydroxymethyl compounds) (all of which are manufactured by Shikoku Chemical Industry Co., Ltd.), etc.

The amount of hardener added relative to the total amount of thermosetting resin components, in terms of solid content, is preferably 0.5 to 15% by mass, more preferably 0.5 to 10% by mass.

(Inorganic Fillers) Thermosetting resin compositions may also contain inorganic fillers. Inorganic fillers are preferably those that improve the adhesion, mechanical strength, and coefficient of linear expansion of the cured product. Examples of inorganic fillers include: silicon dioxide, barium sulfate, barium titanium oxide, silicon dioxide, calcium carbonate, silicon nitride, aluminum nitride, boron nitride, aluminum trioxide, magnesium oxide, aluminum hydroxide, magnesium hydroxide, titanium oxide, mica, talc, clay, organobentonite, copper, gold, silver, palladium, etc. Inorganic fillers can be used alone or in combination.

Among these inorganic fillers, calcium carbonate or silica, barium sulfate, and alumina (hereinafter also referred to as alumina) with excellent low volume expansion are suitable, with silica, alumina, and calcium carbonate being more preferred, silica and alumina being even more preferred, and silica being the most preferred. Silica can be either amorphous or crystalline, or a mixture thereof. Amorphous (molten) silica is particularly preferred. Alumina can be either spinel-type (γ-alumina (low temperature)) or corundum-type (α-alumina (high temperature)). Furthermore, calcium carbonate can be either natural heavy calcium carbonate or synthetic precipitated calcium carbonate.

There are no particular restrictions on the shape of inorganic fillers, including: spherical, needle-like, plate-like, scale-like, hollow, irregular, hexagonal, cubic, and flake-like shapes. However, from the perspective of highly incorporating inorganic fillers, spherical shapes are preferred.

Furthermore, the average particle size of these inorganic fillers is not particularly limited, but is preferably 0.1 μm to 25 μm, more preferably 0.1 μm to 15 μm, and even more preferably 0.3 μm to 10 μm. In addition, the average particle size means the average primary particle size, which can be measured by laser diffraction/scattering method.

Relative to the total amount of the thermosetting resin composition, the amount of inorganic filler, converted to solid content, is preferably 50% by mass or more, more preferably 55% by mass or more and 90% by mass, and even more preferably 55% by mass or more and 85% by mass. If the amount of inorganic filler is within the above range, the cured material is less prone to thermal expansion, and the wafer can be easily monolithized.

(Silane Coupling Agent) Thermosetting resin compositions may further contain silane coupling agents. By incorporating silane coupling agents, the adhesion between inorganic fillers and epoxy resins can be improved, thereby inhibiting crack formation in the cured product.

Examples of silane coupling agents include: epoxy silanes, ethylene silanes, imidazosilanes, silyl silanes, methacryloxysilanes, amino silanes, styryl silanes, isocyanate silanes, sulfide silanes, and ureosilanes. Furthermore, silane coupling agents can also be incorporated by using inorganic fillers that have undergone pre-surface treatment with silane coupling agents.

From the perspective of combining the adhesion and defoaming properties of inorganic fillers and epoxy resins, the preferred dosing ratio of silane coupling agent, calculated in terms of solid content, is 0.05 to 2.5 parts by weight relative to 100 parts by weight of inorganic filler.

(Coloring Agents) Thermosetting resin compositions may also contain coloring agents. There are no particular limitations on the coloring agent; commonly known coloring agents such as red, blue, green, and yellow can be used, as well as any type of pigment, dye, or dyeing agent. However, from the perspective of reducing environmental impact and minimizing the impact on human health, halogen-free coloring agents are preferred.

Red pigments include monoazo, diazo, azo pigments, benzimidazolone, perylene, pyrrolopyrrole, condensed azo, anthraquinone, and quinacrine pigments, among others. Specifically, those with color index numbers (issued by the Society of Dyers and Colourists) can be listed below.

Examples of monoazo red pigments include: Pigment Red 1, 2, 3, 4, 5, 6, 8, 9, 12, 14, 15, 16, 17, 21, 22, 23, 31, 32, 112, 114, 146, 147, 151, 170, 184, 187, 188, 193, 210, 245, 253, 258, 266, 267, 268, 269, etc. Examples of diazo red pigments include: Pigment Red 37, 38, 41, etc. Furthermore, examples of monoazo red pigments include: Pigment Red 48:1, 48:2, 48:3, 48:4, 49:1, 49:2, 50:1, 52:1, 52:2, 53:1, 53:2, 57:1, 58:4, 63:1, 63:2, 64:1, 68, etc. Examples of benzimidazolone red pigments include: Pigment Red 171, 175, 176, 185, 208, etc. Examples of perylene red pigments include: Solvent Red 135, 179, Pigment Red 123, 149, 166, 178, 179, 190, 194, 224, etc. Furthermore, examples of pyrrolopyrrole dione red pigments include: Pigment Red 254, 255, 264, 270, and 272. Examples of condensed azo red pigments include: Pigment Red 220, 144, 166, 214, 220, 221, and 242. Examples of anthraquinone red pigments include: Pigment Red 168, 177, 216, Solvent Red 149, 150, 52, and 207. Examples of quinacrine red pigments include: Pigment Red 122, 202, 206, 207, and 209.

Blue pigments include phthalocyanine and anthraquinone compounds. Pigment-based pigments can be categorized as pigments, such as Pigment Blue 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, and 60. As dyes, Solvent Blue 35, 63, 68, 70, 83, 87, 94, 97, 122, 136, 67, and 70 can be used. In addition to the above, metal-substituted or unsubstituted phthalocyanine compounds can also be used.

Examples of yellow colorants include: monoazo, diazo, condensed azo, benzimidazolone, isoindolinone, and anthraquinone. For instance, anthraquinone yellow colorants include Solvent Yellow 163, Pigment Yellow 24, 108, 193, 147, 199, and 202. Isoindolinone yellow colorants include Pigment Yellow 110, 109, 139, 179, and 185. Condensed azo yellow colorants include Pigment Yellow 93, 94, 95, 128, 155, 166, and 180. Examples of benzimidazolone yellow pigments include: Pigment Yellow 120, 151, 154, 156, 175, 181, etc. Examples of monoazo yellow pigments include: Pigment Yellow 1, 2, 3, 4, 5, 6, 9, 10, 12, 61, 62, 62, 1, 65, 73, 74, 75, 97, 100, 104, 105, 111, 116, 167, 168, 169, 182, 183, etc. Furthermore, examples of diazo yellow colorants include: Pigment Yellow 12, 13, 14, 16, 17, 55, 63, 81, 83, 87, 126, 127, 152, 170, 172, 174, 176, 188, 198, etc.

In addition, colorants such as purple, orange, brown, black, and white can also be added. Specifically, examples include: Pigment Black 1, 6, 7, 8, 9, 10, 11, 12, 13, 18, 20, 25, 26, 28, 29, 30, 31, 32; Pigment Violet 19, 23, 29, 32, 36, 38, 42; Solvent Violet 13, 36; C.I. Pigment Orange 1, 5, 13, 14, 16, 17, 24, 34, 36, 38, 40, 43, 46, 49, 51, 61, 63, 64, 71, 73; Pigment Brown 23, 25; carbon black; titanium oxide, etc.

There is no particular limitation on the amount of colorant added. Relative to the total amount of thermosetting resin components, in terms of solid content, it is preferably 0.01 to 20% by mass, more preferably 0.05 to 10% by mass, and even more preferably 0.1 to 5% by mass.

(Organic solvents) Thermosetting resin compositions may also contain organic solvents used in the preparation of the composition or in adjusting its viscosity. As organic solvents, examples include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as celux ether, methyl celux ether, butyl celux ether, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether (DPM), dipropylene glycol diethyl ether, and tripropylene glycol monomethyl ether; esters such as ethyl acetate, butyl acetate, butyl lactate, celux ether acetate, butyl celux ether acetate, carbitol acetate, butyl carbitol acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, and propylene carbonate; aliphatic hydrocarbons such as octane and decane; and petroleum-based solvents such as petroleum ether, petroleum naphtha, and solvent naphtha. These organic solvents can be used alone or in combination.

(Other Components) The thermosetting resin composition of this invention may also contain a photocurable resin in combination with the thermosetting resin. Examples of photocurable resins include curable resins that can be cured via addition polymerization reactions using free radicals through active energy lines. Specific examples of free radical addition polymerization reactive components having one or more vinyl unsaturated groups in the molecule include commonly known polyester (meth)acrylates, polyether (meth)acrylates, urethane (meth)acrylates, carbonate (meth)acrylates, epoxy (meth)acrylates, etc. Specifically, examples include: diacrylates of glycols such as ethylene glycol, methoxytetraethylene glycol, polyethylene glycol, and propylene glycol; acrylamides such as N,N-dimethylacrylamide, N-hydroxymethylacrylamide, and N,N-dimethylaminopropylacrylamide; alkyl acrylates such as N,N-dimethylaminoethyl acrylate and N,N-dimethylaminopropyl acrylate; polyols such as hexanediol, trimethylolpropane, neopentyl tertrol, dinepentyl tertrol, and trihydroxyethyl cyanate, or their ethylene oxide adducts, propylene oxide adducts, or ε-caprolactone adducts; phenoxy acrylates and bisphenol A diacrylate. Polyacrylates, including esters and ethylene oxide adducts or propylene oxide adducts of phenols; polyacrylates of glycidyl ethers such as diglyceride, triglyceride, trimethylolpropane, and triglyceride triisocyanate; and not limited to the above, acrylates formed by direct acrylate esterification of polyether polyols, polycarbonate diols, hydroxyl-terminated polybutadiene, polyester polyols, etc., or by acrylate esterification of urethane via diisocyanate, and melamine acrylates, and at least one of the corresponding methacrylates. Furthermore, in this specification, (meth)acrylates are generally referred to as acrylates, methacrylates, and mixtures thereof, and other similar expressions are also used. The above-mentioned photocurable resins are preferably liquid.

Furthermore, in the case of promoting the thermosetting reaction with epoxy compounds in the thermosetting resin composition of the present invention, and in the case of making the composition of the present invention an alkaline developing thermosetting resin composition, it may contain a carboxyl-containing resin. The carboxyl-containing resin may be a carboxyl-containing photosensitive resin having an vinyl unsaturated group, and may also not have an aromatic ring.

When using photocurable resins in the thermocurable resin composition of this invention, it is preferable to add a photopolymerization initiator. Examples of such photopolymerization initiators include: benzoin compounds and their alkyl ethers, such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, and benzyl methyl acetone; acetophenones, such as 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, diethoxyacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexylphenyl ketone, and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propane-1-one; methylanthraquinone, 2-ethylanthraquinone, 2 - Anthraquinones such as tertiary butylanthraquinone, 1-chloroanthraquinone, and 2-pentylanthraquinone; thiotonones such as 2,4-diethylthiotonone, 2-chlorothiotonone, 2,4-dichlorothiotonone, 2-methylthiotonone, and 2,4-diisopropylthiotonone; acetophenone dimethyl acetone, benzyl dimethyl acetone, and other acetones; benzophenones such as 4,4-dimethylaminobenzophenone; oxime esters such as 1-[4-(phenylthio)phenyl-1,2-octanedione 2-(neobenzoxime)] and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl] acetophenone neobenzoxime, etc. These can be used alone or in combination of two or more, or in combination with photopolymerization initiators such as triethanolamine, methyldiethanolamine and other tertiary amines, 2-dimethylaminoethylbenzoic acid, ethyl 4-dimethylaminobenzoate and other benzoic acid derivatives.

Photopolymerization initiators should preferably also function as photoalkali generators in cases of heat curing following light irradiation. Examples of photopolymerization initiators that also function as photoalkali generators include α-aminoacetophenones, oxime esters, and compounds with substituents such as acetoylamino group, N-methylated aromatic amine group, N-acetylated aromatic amine group, nitrobenzylaminocarbamate group, and alkoxybenzylaminocarbamate group.

[Applications] The thermosetting resin composition of this invention is preferably used for sealing or protection applications in SAW filters. Furthermore, in addition to the above applications, it is preferably used to form a curing film for printed circuit boards, more preferably for forming a permanent protective film, and particularly preferably for use as an interlayer insulating material, capping layer, solder resist composition, or via filling material. Moreover, even as a thin film, the thermosetting resin composition of this invention can form a cured material with excellent film strength, and is therefore suitable for forming printed circuit boards requiring thin-film properties, such as pattern films in packaging substrates (printed circuit boards used for semiconductor packaging). Furthermore, the thermosetting resin composition of this invention is also suitable for use in flexible printed circuit boards.

[Dry Film] The dry film of the present invention has a first film and a resin layer formed on the first film, wherein the resin layer is formed by a dried coating of the above-mentioned thermosetting resin composition. During dry film formation, the thermosetting resin composition can be diluted with the aforementioned organic solvent to adjust to a suitable viscosity. A uniform thickness is then applied to the first film using a coating device such as a notched wheel coating device, a doctor blade coating device, a lip coater, a rod coater, a squeeze coater, a reverse coating device, a transfer roller coating device, a gravure coater, or a spray coating device. The film is typically dried at a temperature of 50–130°C for 1–30 minutes to obtain the film. There are no particular limitations on the coating thickness, but from the perspective of facilitating monolithic fabrication, a dry film thickness of 10–250 μm, preferably 30–200 μm, is appropriate.

There are no particular limitations on the first film, and conventionally known films can be used. For example, films formed from polyester films such as polyethylene terephthalate and polyethylene naphthalate, polyimide films, polyamide-imide films, polypropylene films, and polystyrene films are suitable. Among these, polyester films are preferred from the viewpoints of heat resistance, mechanical strength, and processability. Furthermore, laminates of these films can also be used as the first film.

Furthermore, from the viewpoint of improving mechanical strength, the aforementioned thermoplastic resin film is preferably a film that extends in a uniaxial or biaxial direction.

There is no particular limitation on the thickness of the first membrane, for example, it can be 10μm to 150μm.

The dry film has a first film to support the resin layer of the structure. In this invention, the first film refers to the film that is at least in contact with the resin layer when it is integrally formed on a substrate or other material by means of heating, in contact with the side of the resin layer formed from the aforementioned curable resin layer formed on the dry film. The first film can also be peeled off from the resin layer in a step after deposition. Especially in this invention, it is preferable to peel it off from the resin layer in a step after curing. After a resin layer, formed from a dried coating of a curable resin composition, is formed on a first film, a peelable second film (covering film) is preferably deposited on the surface of the resin layer to prevent dust and other contaminants from adhering to its surface. In this invention, the second film refers to a film that is peelable from the structure before deposition, formed integrally by heating or other means of depositing onto a substrate or similar material in contact with the resin layer side of the dry film. Examples of peelable second films include polyethylene film, polytetrafluoroethylene film, polypropylene film, and surface-treated paper, as long as the adhesion between the resin layer and the second film is less than the adhesion between the resin layer and the first film when the second film is peeled off.

The thickness of the second membrane is not particularly limited; for example, it can be 10 μm to 150 μm.

To create a cured material on a printed circuit board using dry film, a second film is peeled off from the dry film, and the exposed resin layer is overlapped onto the substrate where the circuit is formed. This is then bonded using a lamination device, forming a resin layer on the substrate. The formed resin layer is then heat-cured to create the cured material. Alternatively, exposure and development can be performed before heat curing, depending on requirements. The first film can be peeled off at any stage before or after curing, and in the case of exposure, it can be peeled off at any stage before or after exposure.

[Curved Material] The cured material of this invention is obtained by curing the above-mentioned thermosetting resin composition. The cured material of this invention is suitable for use in printed circuit boards or electrical and electronic components. The cured material of this invention is resistant to breakage, thermal expansion, and warping; therefore, it facilitates easy monolithic wafer fabrication in the process of sealing multiple wafers at once and then monolithically fabricating each wafer.

[Printed Circuit Board] The printed circuit board of this invention comprises the aforementioned hardened material. As a method for manufacturing the printed circuit board of this invention, for example, the thermosetting resin composition of this invention is adjusted to a viscosity suitable for a coating method using the aforementioned organic solvent, and then coated onto a substrate by methods such as dip coating, spray coating, roller coating, rod coating, screen printing, or curtain coating. The organic solvent contained in the thermosetting resin composition is then evaporated and dried (temporarily dried) at a temperature of 60-100°C, thereby forming a non-sticky resin layer. Furthermore, the resin layer can be hardened by heating at a high temperature. Furthermore, in the case of a dry film, after the resin layer is bonded to the substrate in contact with it using a lamination device or the like, the first film is peeled off, thereby forming a resin layer on the substrate.

As the aforementioned substrate, besides printed circuit boards or flexible printed circuit boards where circuits are pre-formed using materials such as copper, examples include copper-clad laminates of all grades (FR-4, etc.) using materials such as copper-clad laminates for high-frequency circuits. Other substrates include metal substrates, polyimide films, polyethylene terephthalate films, polyethylene naphthalate (PEN) films, glass substrates, ceramic substrates, and wafers. Among these, the copper-clad laminates for high-frequency circuits utilize phenolic paper. It is made of phenol), paper epoxy resin, glass cloth epoxy resin, glass polyimide, glass cloth/non-fiber epoxy resin, glass cloth/paper epoxy resin, synthetic fiber epoxy resin, fluororesin/polyethylene/polyphenylene ether, polyphenylene ether/cyanate, etc.

When dry-filming thermosetting resin compositions, bonding to a substrate is preferably performed using a vacuum lamination apparatus under pressure and heat. By using such a vacuum lamination apparatus, even when the surface of a circuit substrate has irregularities, air bubbles are prevented from entering due to the tight adhesion to the circuit substrate, and the filling of pores in the substrate surface depressions is also improved. The preferred pressure conditions are approximately 0.1 to 2.0 MPa, and the preferred heating conditions are 40 to 120°C.

Curing of the thermosetting resin composition can be performed using methods such as hot air circulation drying ovens, IR (infrared) ovens, heating plates, and convection ovens (using a heat source that heats air by steam to create a counter-current contact between the hot air inside the dryer and the air being blown from nozzles onto the support). From a curing perspective, using a hot air circulation drying oven is preferred. For example, the first stage of heating can be performed at 80-120°C, preferably 90-110°C, for 10-60 minutes, preferably 20-40 minutes, followed by a second stage of heating and hardening at 180-220°C, preferably 190-210°C, for 30-120 minutes, preferably 50-70 minutes, to form a hardened product. This two-stage hardening process helps suppress the formation of bubbles during hardening, which is preferable. Specifically, by allowing residual solvent components to evaporate in the first stage, bubble formation during the actual hardening process can be suppressed. Then, by applying high temperature in the second stage, hardening is completed.

[Electrical and Electronic Components] The electrical and electronic components of this invention have the aforementioned printed circuit board. These components can be used in various conventional electrical devices. Among them, a SAW filter is preferred.

Examples of substrates used as the aforementioned materials include: printed wiring boards, LTCC (Low Temperature Co-fired Ceramics) substrates (also known as low-temperature co-fired ceramic substrates), ceramic substrates, silicon substrates, and metal substrates. Examples of electrical and electronic components include: sensors, MEMS, and SAW chips. Among these, pressure sensors, vibration sensors, and SAW chips are suitable, with SAW chips being particularly preferred.

When dry-filming thermosetting resin compositions, bonding to a substrate is preferably performed using a vacuum lamination device under pressure and heat. By using such a vacuum lamination device, even with uneven surfaces on the substrate to which components are mounted, air bubbles are prevented from entering due to the tight fit, and the sealing of electrical and electronic components is improved. The preferred pressure conditions are approximately 0.1 to 2.0 MPa, and the preferred heating conditions are 40 to 120°C.

Curing of the thermosetting resin composition can be performed using a hot air circulating dryer, an IR oven, a heating plate, a convection oven, etc. (using a heat source that heats the air by steam to create a counter-current flow of hot air within the dryer, or by blowing hot air from a nozzle onto the support). From a curing perspective, a hot air circulating dryer is preferred. For example, the first stage of heating can be performed at 80-120°C, preferably 90-110°C, for 10-60 minutes, preferably 20-40 minutes, followed by a second stage of heating and hardening at 180-220°C, preferably 190-210°C, for 30-120 minutes, preferably 50-70 minutes, to form a hardened product. This two-stage hardening process helps suppress the formation of bubbles during hardening, which is preferable. Specifically, by allowing residual solvent components to evaporate in the first stage, bubble formation during the actual hardening process can be suppressed. Then, by applying high temperature in the second stage, hardening is completed.

Furthermore, when thermosetting resin compositions contain photopolymerization initiators or photoalkali generators that also function as photoalkali generators, the alkali generated by light irradiation before the heating step undergoes an addition reaction with the liquid thermosetting resin (such as epoxy resins with a bisphenol backbone), thereby curing it to deeper layers of the thermosetting resin composition coating. [Example]

The present invention is illustrated in more detail by the following embodiments, but the present invention is not limited to the following embodiments. In addition, unless otherwise stated, "parts" and "%" are quality standards.

<Preparation of Thermosetting Resin Compositions> (Examples 1-3, 5; Comparative Examples 1-4) The solvents with the compositions shown in each of the Examples and Comparative Examples in Table 1 below were placed in a container and heated to 50°C to prevent solvent evaporation. Each epoxy resin was then added and stirred thoroughly to dissolve it. Next, additives and fillers were added, and the mixture was kneaded using a three-roll mill. Then, a hardener, a hardening accelerator, and other resins were added, and the mixture was stirred thoroughly using a mixer to obtain the thermosetting resin composition.

(Example 4) The formulations shown in Table 1 below are used to combine the components and disperse them using a three-roll mill to obtain a hardened resin composition.

[Table 1] Composition thermosetting resin composition Implementation Example 1 Implementation Example 2 Implementation Example 3 Implementation Example 4 Implementation Example 5 Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Bisphenol A type epoxy resin ^*1 20 30 20 1 20 20 20 20 20 Dicyclopentadiene type epoxy resin 1 ^{* 2} 0 0 25 0 0 0 0 0 0 Dicyclopentadiene type epoxy resin 2 ^{* 3} 30 60 0 0 30 30 30 30 30 Phenolic resin varnish type epoxy resin ^*4 40 100 30 0 40 40 40 40 40 Naphthalene-type epoxy resin ^*5 0 0 0 25 0 0 0 0 0 Phenoxy resin ^*6 0 65 0 0 0 0 0 0 0 Acrylic copolymer resin 1 ^{* 7} 500 0 0 0 500 500 500 1000 500 Acrylic copolymer resin 2 ^{* 8} 0 0 200 10 0 0 0 0 0 Hardener 1 (phenolic resin ^{* 9} ) 30 55 20 8 30 30 30 30 30 Hardener 2 (Imidazole ^*10 ) 1 2 1 0 1 1 1 1 1 Silicon dioxide 1 ^{* 11} 0 400 400 0 0 150 0 0 200 Silicon dioxide 2 ^{* 12} 1000 0 0 55 0 0 0 1000 0 Aluminum trioxide ^*13 0 0 0 0 1000 0 500 0 0 Silane coupling agent ^*14 2 0 0 0 2 2 2 2 2 Black paint ^*15 30 0 20 1 30 30 30 30 30 Organic solvent 1 ^{* 16} 0 500 200 0 0 0 0 0 0 Organic solvent 2 ^{* 17} 100 0 0 0 100 100 100 100 100 total 1753 1212 916 100 1753 903 1253 2253 953 Inorganic filler content (%) converted to solid content 81 60 73 60 81 40 69 77 7

In Table 1, the admixture amounts of each component are based on parts by weight. *1: Manufactured by Mitsubishi Chemical Corporation, jER828 *2: Manufactured by Nippon Kayaku Co., Ltd., XD-1000 *3: Manufactured by DIC CORPORATION, HP-7200L *4: Manufactured by DIC CORPORATION, EPICLON N-740 *5: Manufactured by DIC CORPORATION, HP-4032D *6: Manufactured by Mitsubishi Chemical Corporation, YX6954BH30 (solid content: 30% by weight) *7: Manufactured by Nagase ChemteX Corporation, TEISANRESIN SG-P3 (solid content: 15% by weight) *8: Manufactured by Nagase ChemteX Corporation, SG-80H (solid content: 15% by weight) *9: Manufactured by Meiwa Kasei Co., Ltd., HF-1 *10: Manufactured by Shikoku Kasei Kogyo Co., Ltd., 2E4MZ *11: Admatechs Company *12: FB-7SDX (Silicon dioxide, amorphous, spherical, average particle size (D50) 5.5μm) manufactured by Denka Company Limited *13: DAW-07 (Aluminum trioxide, spherical, average particle size (D50) 8.2μm) manufactured by Denka Company Limited *14: KBM-403 manufactured by Shin-Etsu Chemical Industry Co., Ltd. *15: Carbon black *16: Cyclohexanone *17: Diethylene glycol monoethyl ether acetate

<Preparation of Dry Film and its Cured Form> Using a rod coating apparatus, the thermosetting resin composition obtained in each embodiment and comparative example was coated onto a first film (PET film; TN200 manufactured by Toyobo Co., Ltd., 38μm thick, 30cm×30cm) to achieve a cured film thickness of 100μm. Next, using a hot air circulating drying oven, the residual solvent in the resin layer formed by the thermosetting resin composition was dried at 70-120°C (average 100°C) for 5-10 minutes to achieve a residual solvent content of 0.5-2.5% by mass, thus forming a resin layer on the first film. Next, using a roller lamination apparatus set to 80°C, an OPP film (ALPHAN FG-201, Fish eyeless, manufactured by Oji F-Tex Co., Ltd., 16μm thick, 30cm × 30cm) was laminated onto the surface of the resin layer to form a second film, thus producing a dry film.

Next, the second film was peeled off from the dry film and bonded to an 18μm thick copper foil (GTS-MP foil, Furukawa Electric Industries, Ltd.) using a vacuum lamination apparatus (manufactured by Nippon Steel Corporation, MVLP-500) at a lamination temperature of 80-110°C and a pressure of 0.3 MPa. Then, the first film was peeled off, heated at 100°C for 30 minutes in a hot air circulating dryer, and immediately removed from the dryer. It was then immediately heated at 200°C for 60 minutes in another hot air circulating dryer to harden the resin layer. The hardened material was then peeled off from the copper foil. The thickness of the hardened film was 100μm.

<(i) Measurement of Fracture Point Strength> The hardened material obtained above was cut into 70mm × 5mm strips to obtain measurement samples. The obtained samples were measured using a tensile testing machine (Shimadzu Corporation, EZ-SX) under the following measurement conditions. The results are shown in Table 2. (Measurement Conditions) Tensile speed: 1mm/min Measurement temperature: 23°C Clamping distance: 50mm Sample number n=5

<(ii) Measurement of the Coefficient of Linear Expansion> The hardened material obtained above was cut into 15mm × 3mm strips to obtain measurement samples. The obtained samples were measured using a TMA measuring apparatus (TA Instruments, Q400EM) under the following measurement conditions. The average coefficient of linear expansion from 30 to 100°C of the three-stage measurement results was recorded as the coefficient of linear expansion. The results are shown in Table 2. (Measurement Conditions) 1st: 30°C → 300°C, heating at 10°C/min 2nd: 300°C → 30°C, cooling at 10°C/min 3rd: 30°C → 300°C, heating at 10°C/min

<(iii) Measurement of Storage Elasticity> The hardened material obtained above was cut into 30mm × 5mm strips to obtain measurement samples. The samples were measured using a DMA measuring device (Hitachi High-Tech Science Corporation, DMA7100) under the following conditions. The storage elasticity at 30°C was calculated from the measurement results. The results are shown in Table 2. (Measurement Conditions) Measurement Temperature: 30~300°C Heating Rate: 5°C/min Loading Gap: 10 min Frequency: 1Hz Axial Force: 0.05N

<Monolithization Experiment> The 18μm thick copper foil was replaced with a 9.5cm × 11cm, 0.8μm thick etched-out substrate (a substrate made by etching a copper-clad laminate manufactured by Showa Denko Materials Co., Ltd.). The resin layer was cured according to <Preparation of Dry Film and its Cured Material>. Afterwards, the cured material was not peeled off from the etched-out substrate before the experiment. Specifically, using a cutting device (RITOKU Co., Ltd., cutting blade: diamond cutter), the cured material on the etched-out substrate was cut into individual etched-out substrates of 5cm × 5cm size, obtaining individual test pieces. The cut ends of the obtained test pieces were observed under a microscope, and the ease of monolithization was evaluated according to the following criteria. The evaluation results are shown in Table 2. (Evaluation Criteria) ○: The hardened material has no burrs on the end face. ×: The hardened material has burrs on the end face.

[Table 2] Implementation Example 1 Implementation Example 2 Implementation Example 3 Implementation Example 4 Implementation Example 5 Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 (i) Fracture point strength (MPa) 50 95 60 68 80 120 90 40 105 (ii) Linear expansion coefficient (ppm/°C) 8 25 18 33 35 40 45 11 35 (iii) Storage elasticity (GPa) 6 5.5 4.1 3.2 8 1.8 6.5 1 2.5 Monolithic Experiment ○ ○ ○ ○ ○ × × × ×

As can be clearly seen from Table 2, the thermosetting resin composition of the embodiment of this application can easily be monolithically assembled into a chip by optimizing the fracture point strength, coefficient of thermal expansion and storage elasticity.

without

without

Claims (9)

A thermosetting resin composition comprising a thermosetting resin, a thermoplastic resin, a hardener, and an inorganic filler, characterized in that: the thermosetting resin contains a phenolic varnish-type epoxy resin; the thermoplastic resin is a polymer resin with a glass transition temperature below 20°C and a weight average molecular weight of 10,000 or more, and the polymer resin is an acrylate copolymer; the content of the thermoplastic resin, converted from solid content, is 0.5% to 10% by mass of the total amount of the thermosetting resin composition; the hardener is selected from at least one of phenolic resins and imidazole resins; and the inorganic filler is selected from at least one of silica and alumina. The content of the inorganic filler, converted to solids, is 50% or more of the total mass of the thermosetting resin composition; the thermosetting resin composition is heated at 100°C for 30 minutes and then heated at 180°C for 60 minutes to harden it to obtain a hardened product, which satisfies the following conditions: (i) the fracture point strength is 100 MPa or less; (ii) the coefficient of linear expansion is 35 ppm/°C or less; and (iii) the storage elasticity at 30°C is 2 GPa or more. The thermosetting resin composition as described in claim 1, wherein the thermosetting resin further comprises at least one of bisphenol A type epoxy resin and dicyclopentadiene type epoxy resin. The thermosetting resin composition as described in claim 1 or 2, wherein the content of the inorganic filler, converted in terms of solid content, is 55% or more by mass of the total amount of the thermosetting resin composition. The thermosetting resin composition as described in claim 1 or 2, wherein the content of the thermosetting resin, in terms of solid content, is 3 to 40% by mass of the total amount of the thermosetting resin composition. The thermosetting resin composition as described in claim 1 or 2, wherein the content of the hardener, converted in terms of solid content, is 0.5 to 15% by mass of the total thermosetting resin composition. A dry film characterized by having a first film and a resin layer formed on the first film, wherein the resin layer is formed from a dried coating of a thermosetting resin composition as described in any one of claims 1 to 5. A hardener characterized by being obtained by hardening a thermosetting resin composition as described in any one of claims 1 to 5, or by hardening a resin layer of a dry film as described in claim 6. A printed circuit board characterized by having a hardened material as described in claim 7. An electrical component characterized by having a printed circuit board as described in claim 8.