TWI868091B - Resin composition - Google Patents

Abstract

The present invention provides a resin composition that can reduce the dielectric properties of a cured product and inhibit the occurrence of flow marks. The resin composition of the present invention is a resin composition comprising (A) an epoxy resin, (B) a curing agent, and (C) an inorganic filler, wherein the component (B) comprises (B-1) an active ester resin having a softening point of less than 100°C, (B-2) a difunctional active ester resin, or (B-3) an active ester resin having a molecular weight of less than 1,000.

Description

Resin composition

The present invention relates to a resin composition comprising an epoxy resin and a curing agent; a cured product of the resin composition; a resin sheet comprising the resin composition; a circuit substrate comprising the cured product; a semiconductor chip package comprising the cured product; and a semiconductor device having the semiconductor chip package.

In recent years, the demand for small, high-function electronic devices such as smartphones and tablet devices has increased, and with this, the insulating materials used in semiconductor chip packaging for these small electronic devices are required to have higher functionality. Such insulating layers are known to be formed by curing a resin composition (e.g., see Patent Document 1). [Prior Art Document] [Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 2017-008312

[Problems to be solved by the invention]

Insulation materials for semiconductor chip packaging are required to have lower dielectric properties as the demand for miniaturization and thin filming increases in the future. However, among the conventional insulation materials, materials with low dielectric properties are prone to flow marks.

The subject of the present invention is to provide a resin composition that can reduce the dielectric properties of the cured product and inhibit the occurrence of flow marks. [Means for solving the subject]

In order to achieve the object of the present invention, the inventors have actively examined and found that the above-mentioned object can be solved by using (B-1) an active ester resin having a softening point of 100°C or less, (B-2) a bifunctional active ester resin or (B-3) an active ester resin having a molecular weight of 1,000 or less as (B) a hardener, thereby completing the present invention.

That is, the present invention includes the following contents. [1] A resin composition comprising (A) an epoxy resin, (B) a hardener and (C) an inorganic filler, wherein the component (B) comprises (B-1) an active ester resin having a softening point of 100°C or less. [2] The resin composition as described in [1] above, wherein the content of the component (B-1) is 1% by mass to 50% by mass when the non-volatile components in the resin composition are taken as 100% by mass. [3] A resin composition comprising (A) an epoxy resin, (B) a hardener and (C) an inorganic filler, wherein the component (B) comprises (B-2) a bifunctional active ester resin. [4] The resin composition of [3] above, wherein the component (B-2) is a compound represented by formula (1),

[In the formula, ring X, Y and Z each independently represent an aromatic ring which may further have a substituent]. [5] The resin composition of any one of [1] to [4] above, wherein component (B) further comprises one or more curing agents selected from phenolic curing agents, naphthol curing agents, amine curing agents and acid anhydride curing agents. [6] The resin composition of any one of [1] to [5] above, wherein component (A) is a liquid epoxy resin. [7] The resin composition of any one of [1] to [6] above, wherein component (C) has an average particle size of 1 μm to 40 μm. [8] A resin composition as described in any one of [1] to [7] above, wherein the content of component (C) is 80% by mass or more when the non-volatile components in the resin composition are taken as 100% by mass. [9] A resin composition as described in any one of [1] to [8] above, which is liquid at 25°C. [10] A resin composition as described in any one of [1] to [9] above, which is used to form an insulating layer of a semiconductor chip package. [11] A resin composition as described in any one of [1] to [9] above, which is used to form an insulating layer of a circuit substrate. [12] A resin composition as described in any one of [1] to [9] above, which is used to seal a semiconductor chip in a semiconductor chip package. [13] A cured product, which is a cured product of a resin composition as described in any one of [1] to [12]. [14] A resin sheet, which comprises a support and a resin composition layer comprising a resin composition as described in any one of [1] to [12] and disposed on the support. [15] A circuit board, which comprises an insulating layer formed by a cured product of a resin composition as described in any one of [1] to [12]. [16] A semiconductor chip package, which comprises a circuit board as described in [15] and a semiconductor chip mounted on the circuit board. [17] A semiconductor chip package comprising a semiconductor chip and a cured product of a resin composition as described in any one of [1] to [12] above that seals the semiconductor chip. [18] A semiconductor device having a semiconductor chip package as described in [16] or [17] above. [19] A resin composition comprising (A) an epoxy resin, (B) a curing agent, and (C) an inorganic filler, wherein the component (B) comprises (B-3) an active ester resin having a molecular weight of 1,000 or less. [Effect of the invention]

According to the present invention, a resin composition that can reduce the dielectric properties of a cured product and inhibit the occurrence of flow marks can be provided; a cured product of the resin composition; a resin sheet containing the resin composition; a circuit substrate containing the cured product; a semiconductor chip package containing the cured product; and a semiconductor device having the semiconductor chip package.

The present invention is described in detail below with preferred embodiments. However, the present invention is not limited to the embodiments and examples described below, and can be arbitrarily modified and implemented without departing from the scope of the patent application of the present invention and its equivalent scope.

<Resin composition> The resin composition of the present invention comprises (A) an epoxy resin, (B) a hardener, and (C) an inorganic filler. In the first embodiment, the component (B) comprises (B-1) an active ester resin having a softening point of 100°C or less. In the second embodiment, the component (B) comprises (B-2) a bifunctional active ester resin. In the third embodiment, the component (B) comprises (B-3) an active ester resin having a molecular weight of 1,000 or less.

By using these resin compositions, both the dielectric properties of the cured product and the occurrence of flow marks can be reduced. Furthermore, according to these resin compositions, in one embodiment, a cured product having excellent storage elastic modulus and capable of maintaining adhesion to a semiconductor chip for a long period of time can be obtained.

The resin composition of the present invention may further contain any component in addition to (A) epoxy resin, (B) hardener and (C) inorganic filler. Examples of the optional component include (D) hardening accelerator, (E) organic solvent and (F) other additives. The following is a detailed description of each component contained in the resin composition.

<(A) Epoxy resin> The resin composition of the present invention contains (A) epoxy resin.

Examples of the epoxy resin (A) include bixylenol epoxy resins, bisphenol A epoxy resins, bisphenol F epoxy resins, bisphenol S epoxy resins, bisphenol AF epoxy resins, cyclopentadiene epoxy resins, trisphenol epoxy resins, naphthol novolac epoxy resins, phenol novolac epoxy resins, tert-butylcatechol epoxy resins, naphthalene epoxy resins, naphthol epoxy resins, anthracene epoxy resins, condensed epoxy resins, Hydroglycerylamine type epoxy resin, glycidyl ester type epoxy resin, cresol novolac type epoxy resin, biphenyl type epoxy resin, linear aliphatic epoxy resin, epoxy resin having a butadiene structure, alicyclic epoxy resin, heterocyclic epoxy resin, spirocyclic epoxy resin, oxalic acid type epoxy resin, oxalic acid dimethanol type epoxy resin, naphthyl ether type epoxy resin, trihydroxymethyl type epoxy resin, tetraphenylmethane type epoxy resin, etc. The epoxy resin may be used alone or in combination of two or more.

The resin composition preferably includes an epoxy resin having two or more epoxy groups in one molecule as the epoxy resin (A). From the viewpoint of significantly obtaining the desired effect of the present invention, the ratio of the epoxy resin having two or more epoxy groups in one molecule is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass or more relative to 100% by mass of the non-volatile component of the epoxy resin (A).

Epoxy resins include epoxy resins that are liquid at a temperature of 20°C (hereinafter sometimes referred to as "liquid epoxy resins") and epoxy resins that are solid at a temperature of 20°C (hereinafter sometimes referred to as "solid epoxy resins"). In one embodiment, the resin composition of the present invention includes a liquid epoxy resin as the epoxy resin. In one embodiment, the resin composition of the present invention includes a solid epoxy resin as the epoxy resin. Liquid epoxy resins and solid epoxy resins may also be used in combination. The resin composition of the present invention preferably includes only liquid epoxy resins as the epoxy resin.

The liquid epoxy resin is preferably a liquid epoxy resin having two or more epoxy groups in one molecule.

Examples of liquid epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AF type epoxy resins, naphthalene type epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, phenol novolac type epoxy resins, alicyclic epoxy resins having an ester skeleton, cyclohexane type epoxy resins, cyclohexanedimethanol type epoxy resins, and epoxy resins having a butadiene structure.

Specific examples of liquid epoxy resins include "HP4032", "HP4032D", and "HP4032SS" (naphthalene-based epoxy resins) manufactured by DIC Corporation; "828US", "828EL", "jER828EL", "825", and "EPICOTE" manufactured by Mitsubishi Chemical Corporation; "828EL" (bisphenol A type epoxy resin); "jER807" and "1750" (bisphenol F type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "jER152" (phenol novolac type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "630" and "630LSD" (glycidylamine type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "EP-3950S", "EP-3950L", and "EP-3980S" (glycidylamine type epoxy resin) manufactured by ADEKA Corporation; "ZX1059" (a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin) manufactured by Nippon Steel & Sumitomo Metal Chemical Corporation; NAGASE "EX-721" manufactured by CHEMTEX (glycidyl ester type epoxy resin); "CELOXIDE 2021P (CEL2021P)" manufactured by DAICEL (aliphatic epoxy resin with ester skeleton); "PB-3600" manufactured by DAICEL, "JP-100" and "JP-200" manufactured by Nippon Soda Co., Ltd. (epoxy resin with butadiene structure); "ZX1658" and "ZX1658GS" manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd. (liquid 1,4-glycidyl cyclohexane type epoxy resin), etc. These can be used alone or in combination of two or more.

The solid epoxy resin is preferably a solid epoxy resin having three or more epoxy groups in one molecule, and more preferably an aromatic solid epoxy resin having three or more epoxy groups in one molecule.

As the solid epoxy resin, preferred are xylenol type epoxy resin, naphthalene type epoxy resin, naphthalene type tetrafunctional epoxy resin, cresol novolac type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, naphthol type epoxy resin, biphenyl type epoxy resin, naphthyl ether type epoxy resin, anthracene type epoxy resin, bisphenol A type epoxy resin, bisphenol AF type epoxy resin, and tetraphenylethane type epoxy resin.

Specific examples of solid epoxy resins include "HP4032H" manufactured by DIC Corporation (naphthalene-based epoxy resin); "HP-4700" and "HP-4710" manufactured by DIC Corporation (naphthalene-based tetrafunctional epoxy resin); "N-690" manufactured by DIC Corporation (cresol novolac-based epoxy resin); "N-695" manufactured by DIC Corporation (cresol novolac-based epoxy resin); "HP-7200" manufactured by DIC Corporation (dicyclopentadiene-based epoxy resin); "HP-7200H" manufactured by DIC Corporation; H", "HP-7200H", "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP6000" (naphthyl ether type epoxy resin); "EPPN-502H" (trisphenol type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC7000L" (naphthol novolac type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC3000H", "NC3000", "NC3000L" (naphthol novolac type epoxy resin) manufactured by Nippon Kayaku Co., Ltd. ", "NC3100" (biphenyl type epoxy resin); "ESN475V" manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd. (naphthalene type epoxy resin); "ESN485" manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd. (naphthol novolac type epoxy resin); "YX4000H", "YX4000", "YL6121" (biphenyl type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YX4000HK" (xylenol type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YX8800" (anthracene type epoxy resin) manufactured by Mitsubishi Chemical Corporation ; "YX7700" manufactured by Mitsubishi Chemical Corporation (phenolic varnish type epoxy resin containing xylene structure); "PG-100" and "CG-500" manufactured by Osaka Gas Chemical Co., Ltd.; "YL7760" manufactured by Mitsubishi Chemical Corporation (bisphenol AF type epoxy resin); "YL7800" manufactured by Mitsubishi Chemical Corporation (fluorene type epoxy resin); "jER1010" manufactured by Mitsubishi Chemical Corporation (solid bisphenol A type epoxy resin); "jER1031S" manufactured by Mitsubishi Chemical Corporation (tetraphenylethane type epoxy resin), etc. These can be used alone or in combination of two or more.

When a liquid epoxy resin and a solid epoxy resin are used in combination as the epoxy resin (A), the mass ratio of the liquid epoxy resin to the solid epoxy resin (liquid epoxy resin/solid epoxy resin) is preferably 1 or more, more preferably 10 or more, and particularly preferably 50 or more in terms of mass ratio. By making the mass ratio of the liquid epoxy resin to the solid epoxy resin within this range, the desired effect of the present invention can be significantly obtained.

(A) The epoxy equivalent of the epoxy resin is preferably 50 g/eq. to 5000 g/eq., more preferably 50 g/eq. to 3000 g/eq., still more preferably 80 g/eq. to 2000 g/eq., and still more preferably 110 g/eq. to 1000 g/eq. By being within this range, the crosslinking density of the cured resin sheet can be sufficient and an insulating layer with a small surface roughness can be provided. The epoxy equivalent is the mass of the resin containing 1 equivalent of epoxy group. The epoxy equivalent can be measured according to JIS K7236.

(A) The weight average molecular weight (Mw) of the epoxy resin is preferably 100-5000, more preferably 100-3000, and even more preferably 100-1500 in order to significantly obtain the desired effect of the present invention. The weight average molecular weight of the resin is measured by gel permeation chromatography (GPC) as a value converted to polystyrene.

When the "non-volatile components" in the resin composition are set to 100 mass%, the content of the epoxy resin (A) is not particularly limited, but from the viewpoint of significantly obtaining the desired effect of the present invention, it is preferably 1 mass% or more, more preferably 2 mass% or more, still more preferably 3 mass% or more, and particularly preferably 4 mass% or more. The upper limit thereof, from the viewpoint of significantly obtaining the desired effect of the present invention, is preferably 50 mass% or less, more preferably 30 mass% or less, still more preferably 20 mass% or less, and particularly preferably 10 mass% or less.

When the "resin component" in the resin composition is 100 mass%, the content of the epoxy resin (A) is not particularly limited, but from the viewpoint of significantly obtaining the desired effect of the present invention, it is preferably 20 mass% or more, more preferably 30 mass% or more, even more preferably 40 mass% or more, and particularly preferably 45 mass% or more. The upper limit thereof, from the viewpoint of significantly obtaining the desired effect of the present invention, is preferably 90 mass% or less, more preferably 70 mass% or less, even more preferably 60 mass% or less, and particularly preferably 50 mass% or less.

The "resin component" in this specification refers to all non-volatile components remaining after removing the (C) inorganic filler from the resin composition. Therefore, the "resin component" may also include low molecular weight compounds.

<(B) Hardener> The resin composition of the present invention contains (B) hardener. (B) hardener has the function of hardening (A) epoxy resin.

When the "non-volatile components" in the resin composition are set to 100 mass%, the content of the (B) hardener is not particularly limited, but from the viewpoint of remarkably obtaining the desired effect of the present invention, it is preferably 1 mass% or more, more preferably 3 mass% or more, still more preferably 4 mass% or more, and particularly preferably 5 mass% or more. The upper limit thereof, from the viewpoint of remarkably obtaining the desired effect of the present invention, is preferably 50 mass% or less, more preferably 30 mass% or less, still more preferably 20 mass% or less, and particularly preferably 10 mass% or less.

When the "resin component" in the resin composition is 100 mass%, the content of the (B) hardener is not particularly limited, but from the viewpoint of remarkably obtaining the desired effect of the present invention, it is preferably 20 mass% or more, more preferably 30 mass% or more, even more preferably 40 mass% or more, and particularly preferably 50 mass% or more. The upper limit thereof, from the viewpoint of remarkably obtaining the desired effect of the present invention, is preferably 90 mass% or less, more preferably 70 mass% or less, even more preferably 60 mass% or less, and particularly preferably 55 mass% or less.

In the first embodiment, the (B) curing agent comprises (B-1) an active ester resin having a softening point of 100°C or less. In the second embodiment, the (B) component comprises (B-2) a bifunctional active ester resin. In the third embodiment, the (B) component comprises (B-3) an active ester resin having a molecular weight of 1,000 or less.

The so-called active ester resin refers to an ester compound that can undergo an addition reaction with the epoxy group of the epoxy resin. The active ester resin has the characteristic of not generating a hydroxyl group due to the addition reaction with the epoxy group of the epoxy resin. Therefore, by using the active ester resin as a hardener, the concentration of polar groups in the obtained hardened material can be reduced, so low dielectric properties can be achieved.

<(B-1) Active ester resin with a softening point of 100°C or less> The active ester resin of the component (B-1) is not particularly limited as long as it has a softening point of 100°C or less. The softening point can be measured by the global method based on, for example, JIS K2351. By using the component (B-1), the composition uniformity of the resin composition can be improved, so the occurrence of flow marks can be suppressed. As the component (B-1), a bifunctional active ester resin with a softening point of 100°C or less is preferred (the "bifunctional active ester resin" is described below), and a bifunctional active ester resin represented by formula (1) with a softening point of 100°C or less is more preferred.

[wherein, rings X, Y and Z each independently represent an aromatic ring which may further have a substituent], and preferably the bifunctional active ester resin represented by formula (2) has a softening point of 100°C or less,

[In the formula, rings A, B, C, D and E each independently represent a benzene ring which may further have a substituent].

The "aromatic ring" in the present invention refers to a ring that follows Hückel's rule and has 4n+2 electrons (n is a natural number) in the π-electron system of the ring, such as aromatic hydrocarbon rings and aromatic heterocyclic rings.

The term "aromatic hydrocarbon ring" as used in this specification means an aromatic ring having carbon atoms as ring constituent atoms. The "aromatic hydrocarbon ring" is preferably an aromatic hydrocarbon ring having 6 to 14 carbon atoms, and more preferably an aromatic hydrocarbon ring having 6 to 10 carbon atoms. Examples of the "aromatic hydrocarbon ring" include benzene ring, naphthalene ring, anthracene ring, and the like.

The term "aromatic heterocycle" as used herein means an aromatic ring containing heteroatoms other than carbon atoms such as nitrogen atoms, sulfur atoms, oxygen atoms, etc. (preferably 1 to 4 atoms) as ring constituent atoms. The "aromatic heterocycle" is preferably an aromatic heterocycle with 5 to 14 members, and more preferably an aromatic heterocycle with 5 to 10 members. Examples of the "aromatic heterocyclic ring" include a thiophene ring, a furan ring, a pyrrole ring, an imidazole ring, a pyrazole ring, a thiazole ring, an isothiazole ring, an oxazole ring, an isoxazole ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, a 1,2,4-oxadiazole ring, a 1,3,4-oxadiazole ring, a 1,2,4-thiadiazole ring, a 1 , a 5- or 6-membered monocyclic aromatic heterocycle such as a 3,4-thiadiazole ring, a triazole ring, a tetrazole ring, or a triazine ring; an 8- to 14-membered condensed aromatic heterocycle such as a benzothiophene ring, a benzofuran ring, a benzimidazole ring, a benzoxazole ring, a benzoisoxazole ring, a benzothiazole ring, a benzoisothiazole ring, or a benzotriazole ring.

The further substituent in the "aromatic ring which may further have a substituent" of formula (1) or the "benzene ring which may further have a substituent" of formula (2) is not particularly limited, and examples thereof include a halogen atom, an alkyl group, an alkenyl group, an alkoxy group, an alkylcarbonyl group, an aryl group, an aryloxy group, an arylcarbonyl group, an arylalkyl group, an aromatic heterocyclic group, a non-aromatic heterocyclic group, and the like.

In the present specification, examples of the "halogen atom" include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, and the like.

In the present specification, "alkyl" means a linear, branched or cyclic monovalent aliphatic saturated hydrocarbon group. The number of carbon atoms in the "alkyl" is preferably 1 to 6, more preferably 1 to 4, and even more preferably 1 to 3. Examples of the "alkyl" include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, 1-ethylpropyl, hexyl, isohexyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, 3,3-dimethylbutyl, 2-ethylbutyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and the like.

In the present specification, "alkenyl" means a linear, branched or cyclic monovalent unsaturated aliphatic hydrocarbon group having at least one carbon-carbon double bond. The number of carbon atoms in the "alkenyl" is preferably 2 to 6, more preferably 2 to 4, and even more preferably 2 or 3. Examples of the "alkenyl" include vinyl, 1-propenyl, 2-propenyl, 2-methyl-1-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, 3-methyl-2-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 4-methyl-3-pentenyl, 1-hexenyl, 3-hexenyl, 5-hexenyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, and the like.

In the present specification, "alkoxy" means a monovalent group formed by an alkyl group bonded to an oxygen atom (alkyl-O-). The number of carbon atoms in the "alkoxy" is preferably 1 to 6, more preferably 1 to 4, and even more preferably 1 to 3. Examples of the "alkoxy" include methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, pentyloxy, hexyloxy, and the like.

In the present specification, "alkylcarbonyl" means a monovalent group formed by bonding an alkyl group to a carbonyl group (alkyl-CO-). The number of carbon atoms in the "alkylcarbonyl" is preferably 2 to 7, more preferably 2 to 5, and even more preferably 2 to 4. Examples of the "alkylcarbonyl" include acetyl, propionyl, butyryl, 2-methylpropionyl, pentyl, 3-methylbutyryl, 2-methylbutyryl, 2,2-dimethylpropionyl, hexyl, heptyl, and the like.

In the present specification, "aryl" means a monovalent aromatic alkyl group. The number of carbon atoms in the "aryl" is preferably 6 to 14, more preferably 6 to 10. Examples of the "aryl" include phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl, 2-anthryl, 9-anthryl, and the like.

In the present specification, "aryloxy" means a monovalent group formed by an aryl group bonded to an oxygen atom (aryl-O-). The number of carbon atoms in the "aryloxy" is preferably 6 to 14, more preferably 6 to 10. Examples of the "aryloxy" include phenoxy and naphthoxy.

In the present specification, "arylcarbonyl" means a monovalent group formed by bonding an aryl group to a carbonyl group (aryl-CO-). The number of carbon atoms in the "arylcarbonyl" is preferably 7 to 15, more preferably 7 to 11. Examples of the "arylcarbonyl" include benzoyl, 1-naphthoyl, 2-naphthoyl, and the like.

In the present specification, "aralkyl" means an alkyl group substituted with 1 or 2 or more aryl groups. The number of carbon atoms in the "aralkyl" is preferably 7 to 15, more preferably 7 to 11. Examples of the "aralkyl" include benzyl, phenethyl, 2-naphthylmethyl, and the like.

In the present specification, "aromatic heterocyclic group" means an aromatic cyclic group containing (preferably 1 to 4) heteroatoms such as nitrogen atoms, sulfur atoms, oxygen atoms, etc. other than carbon atoms as ring-constituting atoms. The "aromatic heterocyclic group" is preferably an aromatic heterocyclic group having 5 to 14 members, and more preferably an aromatic heterocyclic group having 5 to 10 members. Examples of the “aromatic heterocyclic group” include 5- or 6-membered monocyclic aromatic heterocyclic groups such as thienyl, furanyl, pyrrolyl, imidazolyl, pyrazolyl, thiazolyl, isothiazolyl, oxazolyl, isoxazolyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, 1,2,4-oxadiazolyl, 1,3,4-oxadiazolyl, 1,2,4-thiadiazolyl, 1,3,4-thiadiazolyl, triazolyl, tetrazolyl, and triazinyl; and 8-14-membered condensed aromatic heterocyclic groups such as benzothienyl, benzofuranyl, benzimidazolyl, benzoxazolyl, benzoisoxazolyl, benzothiazolyl, benzoisothiazolyl, and benzotriazolyl.

In the present specification, "non-aromatic heterocyclic group" means a non-aromatic heterocyclic group containing (preferably 1 to 4) heteroatoms such as nitrogen atoms, sulfur atoms, oxygen atoms, etc. other than carbon atoms as ring-constituting atoms. The "non-aromatic heterocyclic group" is preferably a 3-14-membered non-aromatic heterocyclic group, and more preferably a 4-10-membered non-aromatic heterocyclic group. Examples of the “non-aromatic heterocyclic group” include aziridinyl, cyclooxypropyl, cyclothiopropyl, azetidinyl, cyclooxybutyl, cyclothiobutyl, tetrahydrothiophenyl, tetrahydrofuranyl, pyrrolinyl, pyrrolidinyl, imidazolinyl, imidazolidinyl, oxazolinyl, oxazolidinyl, pyrazolinyl, pyrazolidinyl, thiazolinyl, thiazolidinyl, tetrahydroisothiazolyl, tetrahydrofuranyl, 3-8 membered monocyclic non-aromatic heterocyclic groups such as hydrooxazolyl, tetrahydroisoxazolyl, piperidinyl and piperazinyl; 9-14 membered condensed non-aromatic heterocyclic groups such as dihydrobenzofuranyl, dihydrobenzimidazolyl, dihydrobenzoxazolyl, dihydrobenzothiazolyl, dihydrobenzoisothiazolyl, dihydronaphtho[2,3-b]thienyl and tetrahydroisoquinolinyl.

In formula (1), rings X, Y and Z are preferably independently an aromatic hydrocarbon ring which may further have a substituent, more preferably a benzene ring or a naphthyl ring which may further have a substituent, and even more preferably an unsubstituted benzene ring or a naphthyl ring.

In formula (2), rings A, B, C, D and E are preferably unsubstituted benzene rings.

The softening point of the component (B-1) is preferably 90°C or lower, more preferably 85°C or lower, and even more preferably 80°C or lower.

The molecular weight of the component (B-1) is preferably 1,000 or less, more preferably 700 or less, further preferably 600 or less, further preferably 500 or less, and particularly preferably 450 or less. The lower limit is not particularly limited, and may be 200 or more.

A specific example of the component (B-1) is represented by formula (3):

Representing compounds, etc.

The component (B-1) may be a commercially available one or may be synthesized by a known method. The component (B-1) may be used alone or in combination of two or more.

<(B-2) Bifunctional active ester resin> The active ester resin of component (B-2) is not particularly limited as long as it is bifunctional. The so-called bifunctional active ester resin refers to a compound having two ester structures that can react with the epoxy groups of the epoxy resin. Since the composition uniformity of the resin composition can be improved by using component (B-2), the occurrence of flow marks can be suppressed. As component (B-2), the preferred bifunctional active ester resin is represented by formula (1),

[wherein, rings X, Y and Z each independently represent an aromatic ring which may further have a substituent], more preferably a bifunctional active ester resin represented by formula (2),

[In the formula, rings A, B, C, D and E each independently represent a benzene ring which may further have a substituent].

The softening point of the component (B-2) is preferably 100°C or lower, more preferably 90°C or lower, further preferably 85°C or lower, and particularly preferably 80°C or lower.

The molecular weight of the component (B-2) is preferably 1,000 or less, more preferably 700 or less, still more preferably 600 or less, still more preferably 500 or less, and particularly preferably 450 or less. The lower limit of the molecular weight of the component (B-2) is not particularly limited, and may be 200 or more.

A specific example of the component (B-2) is represented by formula (3):

Representing compounds, etc.

The component (B-2) may be a commercially available one or may be synthesized by a known method. The component (B-2) may be used alone or in combination of two or more.

<(B-3) Active ester resin with a molecular weight of 1,000 or less> The active ester resin of the component (B-3) is not particularly limited as long as the molecular weight is 1,000 or less. Since the composition uniformity of the resin composition can be improved by using the component (B-3), the occurrence of flow marks can be suppressed. The component (B-3) is preferably a bifunctional active ester resin with a molecular weight of 1,000 or less (as described above for the "bifunctional active ester resin"), and more preferably a bifunctional active ester resin represented by formula (1) with a molecular weight of 1,000 or less.

[wherein, rings X, Y and Z each independently represent an aromatic ring which may further have a substituent], preferably a bifunctional active ester resin represented by formula (2) having a molecular weight of 1,000 or less,

[In the formula, rings A, B, C, D and E each independently represent a benzene ring which may further have a substituent].

The softening point of the component (B-3) is preferably 100°C or lower, more preferably 90°C or lower, further preferably 85°C or lower, and particularly preferably 80°C or lower.

The molecular weight of the component (B-3) is preferably 700 or less, more preferably 600 or less, still more preferably 500 or less, and particularly preferably 450 or less. The lower limit of the molecular weight of the component (B-3) is not particularly limited, and may be 200 or more.

A specific example of the component (B-3) is represented by formula (3):

Representing compounds, etc.

The component (B-3) may be a commercially available one or may be synthesized by a known method. The component (B-3) may be used alone or in combination of two or more.

When the "non-volatile component" in the resin composition is set to 100 mass%, the content of the component (B-1), the component (B-2) or the component (B-3) is not particularly limited, but from the viewpoint of significantly obtaining the desired effect of the present invention, it is preferably 1 mass% or more, more preferably 1.5 mass% or more, still more preferably 2 mass% or more, still more preferably 2.5 mass% or more, and particularly preferably 3 mass% or more. The upper limit thereof, from the viewpoint of significantly obtaining the desired effect of the present invention, is preferably 50 mass% or less, more preferably 20 mass% or less, still more preferably 10 mass% or less, and particularly preferably 5 mass% or less.

When the "resin component" in the resin composition is 100 mass%, the content of the component (B-1), the component (B-2) or the component (B-3) is not particularly limited, but from the viewpoint of significantly obtaining the desired effect of the present invention, it is preferably 10 mass% or more, more preferably 15 mass% or more, even more preferably 20 mass% or more, and particularly preferably 25 mass% or more. The upper limit thereof, from the viewpoint of significantly obtaining the desired effect of the present invention, is preferably 60 mass% or less, more preferably 50 mass% or less, even more preferably 45 mass% or less, and particularly preferably 40 mass% or less.

The mass ratio of the component (B-1), the component (B-2) or the component (B-3) to the hardener (B) is not particularly limited, but from the viewpoint of significantly obtaining the desired effect of the present invention, when the hardener (B) in the resin composition is 100 mass%, it is preferably 5 mass% or more, more preferably 15 mass% or more, even more preferably 25 mass% or more, and particularly preferably 35 mass% or more. The upper limit is preferably 100 mass% or less, more preferably 90 mass% or less, even more preferably 80 mass% or less, and particularly preferably 75 mass% or less.

<Any hardener other than components (B-1) to (B-3)> (B) hardener may further include any other hardener other than components (B-1), (B-2) or (B-3). Any hardener other than components (B-1), (B-2) or (B-3) is not particularly limited as long as it has the function of hardening the epoxy resin. Examples include phenol hardeners, naphthol hardeners, acid anhydride hardeners, active ester hardeners other than components (B-1), (B-2) or (B-3), benzoxazine hardeners, cyanate hardeners, carbodiimide hardeners and amine hardeners. Among them, phenol hardeners, naphthol hardeners, amine hardeners and acid anhydride hardeners are preferred, and acid anhydride hardeners are more preferred. These hardeners may be used alone or in combination of two or more.

As the phenolic hardener and the naphthol hardener, from the viewpoint of heat resistance and water resistance, a phenolic hardener having a novolac structure or a naphthol hardener having a novolac structure is preferred. From the viewpoint of adhesion to the adherend, a nitrogen-containing phenolic hardener or a nitrogen-containing naphthol hardener is preferred, and a phenolic hardener having a triazine skeleton or a naphthol hardener having a triazine skeleton is more preferred. Among them, from the viewpoint of highly satisfying heat resistance, water resistance and adhesion, a phenolic novolac resin having a triazine skeleton is preferred. Specific examples of phenolic hardeners and naphthol hardeners include "MEH-7700", "MEH-7810", and "MEH-7851" manufactured by Meiwa Chemicals, "NHN", "CBN", and "GPH" manufactured by Nippon Kayaku Co., Ltd., "SN-170", "SN-180", "SN-190", "SN-475", "SN-485", "SN-495", "SN-375", and "SN-395" manufactured by Nippon Steel & Sumitomo Chemicals Corporation, and "LA-7052", "LA-7054", "LA-3018", "LA-3018-50P", "LA-1356", "TD2090", and "TD-2090-60M" manufactured by DIC Corporation.

Examples of the acid anhydride curing agent include a curing agent having one or more acid anhydride groups in one molecule. Specific examples of the acid anhydride curing agent include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnalidic anhydride, hydrogenated methylnalidic anhydride, trialkyltetrahydrophthalic anhydride, dodecylsuccinic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, trimellitic anhydride, pyromellitic anhydride, diphenyl Ketone tetracarboxylic dianhydride, biphenyl tetracarboxylic dianhydride, naphthalene tetracarboxylic dianhydride, oxydiphthalic dianhydride, 3,3',4,4'-diphenylsulfonate tetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-c]furan-1,3-dione, ethylene glycol bis(trimellitic anhydride), styrene-maleic acid resin copolymerized with maleic acid, etc. Examples of commercially available acid anhydride hardeners include "HNA-100", "MH-700", "MTA-15", "DDSA", "HF-08", and "OSA" manufactured by Shin Nippon Chemical Co., Ltd., "YH306" and "YH307" manufactured by Mitsubishi Chemical Corporation, "H-TMAn" manufactured by Mitsubishi Gas Chemical Co., Ltd., and "HN-2200", "HN-2000", "HN-5500", and "MHAC-P" manufactured by Hitachi Chemical Co., Ltd.

The active ester curing agent other than component (B-1), component (B-2) or component (B-3) is not particularly limited, but generally, it is preferred to use a compound having three or more highly reactive ester groups in one molecule, such as phenol esters, thiophenol esters, N-hydroxylamine esters, esters of heterocyclic hydroxyl compounds, etc. The active ester curing agent is preferably obtained by a condensation reaction of a carboxylic acid compound and/or a thiocarboxylic acid compound with a hydroxyl compound and/or a thiol compound. In particular, from the viewpoint of improving heat resistance, an active ester curing agent obtained from a carboxylic acid compound and a hydroxyl compound is preferred, and an active ester curing agent obtained from a carboxylic acid compound and a phenol compound and/or a naphthol compound is more preferred. Examples of carboxylic acid compounds include compounds having three or more carboxyl groups. Examples of the phenolic compound or naphthol compound include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalein, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, pyrogallol, dicyclopentadiene-type diphenol compounds, and phenol novolac. Here, the so-called "dicyclopentadiene-type diphenol compound" refers to a diphenol compound obtained by condensing two molecules of phenol into one molecule of dicyclopentadiene.

Specifically, preferred are active ester compounds containing dicyclopentadiene-type diphenol structures, active ester compounds containing naphthalene structures, active ester compounds containing acetylated phenol novolacs, and active ester compounds containing benzoylated phenol novolacs, among which active ester compounds containing naphthalene structures and active ester compounds containing dicyclopentadiene-type diphenol structures are more preferred. The so-called "dicyclopentadiene-type diphenol structure" means a divalent structural unit containing phenylene-dicyclopentylene-phenylene.

Examples of commercially available active ester curing agents other than component (B-1), component (B-2) or component (B-3) include active ester compounds containing a dicyclopentadiene-type diphenol structure, such as "EXB9451", "EXB9460", "EXB9460S", "HPC-8000", "HPC-8000H", "HPC-8000-65T", "HPC-8000H-65TM", "EXB-8000L", and "EXB-8000L-65TM" (manufactured by DIC Corporation); examples of commercially available active ester compounds containing a naphthalene structure include "EXB9416-70BK", "EXB- 8150-65T" (manufactured by DIC Corporation); as an example of the active ester compound of the acetylated phenolic novolac, "DC808" (manufactured by Mitsubishi Chemical Corporation); as an example of the active ester compound of the benzoylated phenolic novolac, "YLH1026" (manufactured by Mitsubishi Chemical Corporation); as an example of the active ester hardener of the acetylated phenolic novolac, "DC808" (manufactured by Mitsubishi Chemical Corporation); as an example of the active ester hardener of the benzoylated phenolic novolac, "YLH1026" (manufactured by Mitsubishi Chemical Corporation), "YLH1030" (manufactured by Mitsubishi Chemical Corporation), "YLH1048" (manufactured by Mitsubishi Chemical Corporation), etc.

Specific examples of benzoxazine-based hardeners include "JBZ-OP100D" and "ODA-BOZ" manufactured by JFE Chemicals, "HFB2006M" manufactured by Showa High Polymer, and "P-d" and "F-a" manufactured by Shikoku Chemicals.

Examples of cyanate curing agents include bisphenol A dicyanate, polyphenol cyanate (oligo(3-methylene-1,5-phenylene cyanate)), 4,4'-methylenebis(2,6-dimethylphenyl cyanate), 4,4'-ethylenediphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenylpropane, 1,1-bis(4-cyanatephenylmethane) , bis(4-cyanate-3,5-dimethylphenyl)methane, 1,3-bis(4-cyanatephenyl-1-(methylethylidene))benzene, bis(4-cyanatephenyl)sulfide, and bis(4-cyanatephenyl)ether, etc., multifunctional cyanate resins derived from phenol novolac and cresol novolac, etc., prepolymers of these cyanate resins by partially triazineization, etc. Specific examples of cyanate curing agents include "PT30" and "PT60" (both phenol novolac type multifunctional cyanate resins), "BA230", "BA230S75" (prepolymers of trimers of bisphenol A dicyanate partially or completely triazineized), etc., manufactured by LONZA Co., Ltd. of Japan.

Specific examples of carbodiimide-based hardeners include "V-03" and "V-07" manufactured by Nisshinbo Chemical Co., Ltd.

Examples of amine-based hardeners include hardeners having one or more amino groups in one molecule, such as aliphatic amines, polyether amines, alicyclic amines, aromatic amines, etc. Among them, aromatic amines are preferred from the viewpoint of exerting the desired effect of the present invention. The amine-based hardener is preferably a primary amine or a secondary amine, and more preferably a primary amine. Specific examples of amine-based curing agents include 4,4'-methylenebis(2,6-dimethylaniline), diphenyldiaminosulfonate, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfonate, 3,3'-diaminodiphenylsulfonate, m-phenyldiamine, m-xylyldiamine, diethyltoluenediamine, 4,4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dihydroxybenzidine, 2,2-bis(3-amino)benzidine, bis(4-aminophenoxy)phenyl)sulfone, bis(4-(4-aminophenoxy)phenyl)sulfone, and the like. Amine hardeners that can be used are commercially available products, for example, "KAYABOND C-200S", "KAYABOND C-100", "KAYAHARD A-A", "KAYAHARD A-B", "KAYAHARD A-S" manufactured by Nippon Kayaku Co., Ltd., and "EPICURE W" manufactured by Mitsubishi Chemical Corporation.

When the resin composition contains any curing agent other than component (B-1), component (B-2) or component (B-3), the content of any curing agent other than component (B-1), component (B-2) or component (B-3) is not particularly limited, but is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, further preferably 1% by mass or more, and particularly preferably 1.5% by mass or more. The upper limit is preferably 50% by mass or less, more preferably 20% by mass or less, further preferably 10% by mass or less, and particularly preferably 5% by mass or less.

When the resin composition contains any curing agent other than component (B-1), component (B-2) or component (B-3), the content of any curing agent other than component (B-1), component (B-2) or component (B-3) is not particularly limited, but is preferably 1% by mass or more, more preferably 5% by mass or more, further preferably 10% by mass or more, and particularly preferably 15% by mass or more, and the upper limit is preferably 60% by mass or less, more preferably 50% by mass or less, further preferably 40% by mass or less, and particularly preferably 30% by mass or less.

The amount ratio of (A) epoxy resin to (B) hardener is preferably in the range of 1:0.2 to 1:2, more preferably 1:0.3 to 1:1.5, and even more preferably 1:0.4 to 1:1.2, based on the ratio of [the total number of epoxy groups in the epoxy resin]:[the total number of reactive groups in the hardener]. Here, the reactive groups of the hardener are active hydroxyl groups, active ester groups, etc., which vary depending on the type of hardener. The total number of epoxy groups of epoxy resins is the total number of all epoxy resins obtained by dividing the mass of non-volatile components of each epoxy resin by the epoxy equivalent, and the total number of reactive groups of hardeners is the total number of all hardeners obtained by dividing the mass of non-volatile components of each hardener by the reactive group equivalent. By setting the ratio of epoxy resin to hardener within this range, the heat resistance of the obtained hardened material can be further improved.

<(C) Inorganic filler> The resin composition of the present invention contains (C) an inorganic filler.

(C) The material of the inorganic filler is not particularly limited, but examples thereof include silicon oxide, aluminum oxide, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, aluminum hydroxide, magnesium hydroxide, carbon The inorganic filler may be calcium tantalum, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide, barium titanate, barium zirconate titanate, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium tungstate phosphate, and silicon oxide and aluminum oxide are particularly preferred. Examples of silicon oxide include amorphous silicon oxide, molten silicon oxide, crystalline silicon oxide, synthetic silicon oxide, and hollow silicon oxide. Spherical silicon oxide is preferred as silicon oxide. (C) The inorganic filler may be used alone or in combination of two or more.

Examples of commercially available products of (C) inorganic fillers include "UFP-30" manufactured by Denka Kagaku Kogyo Co., Ltd.; "SP60-05" and "SP507-05" manufactured by Nippon Steel & Sumitomo Metal Materials Corporation; "YC100C", "YA050C", "YA050C-MJE", "YA010C", "FE9 series", "FEB series", and "FED series" manufactured by ADMATECHS; "UFP-30" manufactured by DENKA Corporation; "SILFIL NSS-3N", "SILFIL NSS-4N", and "SILFIL NSS-5N" manufactured by Tokuyama Corporation; "SC2500SQ", "SO-C4", "SO-C2", and "SO-C1" manufactured by ADMATECHS; and the like.

(C) The average particle size of the inorganic filler is not particularly limited, but from the viewpoint of suppressing the occurrence of flow marks, it is preferably 40 μm or less, more preferably 30 μm or less, more preferably 25 μm or less, still more preferably 20 μm or less, and particularly preferably 15 μm or less. The lower limit of the average particle size of the inorganic filler is not particularly limited, but it is preferably 0.1 μm or more, more preferably 1 μm or more, still more preferably 3 μm or more, still more preferably 5 μm or more, still more preferably 7 μm or more, and particularly preferably 8 μm or more. The average particle size of the inorganic filler can be measured by the laser diffraction/scattering method based on the Mie scattering theory. Specifically, a laser diffraction particle size distribution measuring device can be used to make a particle size distribution of an inorganic filler based on a volume basis, and the median diameter can be used for measurement. A sample for measurement can be preferably one in which 100 mg of an inorganic filler and 10 g of methyl ethyl ketone are measured in an ampoule and dispersed by ultrasound for 10 minutes. The sample for measurement is a laser diffraction particle size distribution measuring device, and the wavelength of the light source is set to blue and red. The particle size distribution of the inorganic filler based on a volume basis is measured by a flow cell method, and the average particle size is calculated from the obtained particle size distribution as the median diameter. An example of a laser diffraction particle size distribution measuring device is "LA-960" manufactured by Horiba, Ltd.

From the viewpoint of improving moisture resistance and dispersibility, the (C) inorganic filler is preferably treated with one or more of the following surface treatment agents, wherein the surface treatment agent is an aminosilane coupling agent, an epoxysilane coupling agent, a butylsilane coupling agent, an alkoxysilane compound, an organic silazane compound, a titanium ester coupling agent, etc. Examples of commercially available surface treatment agents include "KBM403" (3-glycidyloxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., "KBM803" (3-butylpropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., "KBE903" (3-aminopropyltriethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., and "SZ-31" (hexamethyldisilazane) manufactured by Shin-Etsu Chemical Co., Ltd. silane), Shin-Etsu Chemical Co., Ltd.'s "KBM103" (phenyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM-4803" (long-chain epoxy-type silane coupling agent), Shin-Etsu Chemical Co., Ltd.'s "KBM-7103" (3,3,3-trifluoropropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM503" (3-methacryloyloxypropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM5783" (N-phenyl-3-aminooctyltrimethoxysilane), etc.

The degree of surface treatment with the surface treatment agent is preferably limited to a specific range from the viewpoint of improving the dispersibility of the inorganic filler. Specifically, 100% by mass of the inorganic filler is preferably surface treated with 0.2% by mass to 5% by mass of the surface treatment agent, preferably 0.2% by mass to 3% by mass, and more preferably 0.3% by mass to 2% by mass.

The degree of surface treatment using a surface treatment agent can be evaluated by the amount of carbon per unit surface area of the inorganic filler. The amount of carbon per unit surface area of the inorganic filler is preferably 0.02 mg/ ^m2 or more, more preferably 0.1 mg/ ^m2 or more, and more preferably 0.2 mg/ ^m2 or more from the viewpoint of improving the dispersibility of the inorganic filler. On the other hand, from the viewpoint of preventing the melt viscosity of the resin varnish and the melt viscosity of the flake form from increasing, it is preferably 1 mg/m2 or ^less , more preferably 0.8 mg/ ^m2 or less, and more preferably 0.5 mg/ ^m2 or less.

(C) The amount of carbon per unit surface area of the inorganic filler can be measured by washing the surface-treated inorganic filler with a solvent (e.g., methyl ethyl ketone (MEK)). Specifically, a sufficient amount of MEK as a solvent is added to the inorganic filler surface-treated with a surface treatment agent, and ultrasonic washing is performed at 25°C for 5 minutes. After removing the supernatant and drying the solids, a carbon analyzer is used to measure the amount of carbon per unit surface area of the inorganic filler. As for the carbon analyzer, the "EMIA-320V" manufactured by Horiba, Ltd. can be used.

(C) The specific surface area of the inorganic filler is preferably 0.01 ^{m 2} /g or more, more preferably 0.1 m 2 /g or more, and particularly preferably 0.2 m ² /g or more, from the viewpoint of further improving the effect of the present invention. The upper limit is not particularly limited, but is preferably 50 ^{m 2 /g or less, more preferably 20 m 2 / g} or less, 10 m ² /g or less, or 5 m ² /g or less. The specific surface area of the inorganic filler can be obtained by adsorbing nitrogen on the sample surface according to the BET method using a specific surface area measuring device (Macsorb HM-1210 manufactured by MOUNTECH), and using the BET multi-point method to calculate the specific surface area.

(C) The content of the inorganic filler is not particularly limited, but when the "non-volatile component" in the resin composition is set to 100 mass%, it is preferably 20 mass% or more, more preferably 50 mass% or more, more preferably 70 mass% or more, and particularly preferably 80 mass% or more. The upper limit is not particularly limited, but can be, for example, 98 mass% or less, 95 mass% or less, 92 mass% or less, 90 mass% or less, etc.

<(D) Hardening accelerator> The resin composition of the present invention may contain (D) a hardening accelerator as an optional component.

Examples of the (D) hardening accelerator include phosphorus-based hardening accelerators, amine-based hardening accelerators, imidazole-based hardening accelerators, guanidine-based hardening accelerators, and metal-based hardening accelerators. Among them, phosphorus-based hardening accelerators, amine-based hardening accelerators, imidazole-based hardening accelerators, and metal-based hardening accelerators are preferred, amine-based hardening accelerators, imidazole-based hardening accelerators, and metal-based hardening accelerators are more preferred, and imidazole-based hardening accelerators are particularly preferred. The hardening accelerators may be used alone or in combination of two or more.

Examples of phosphorus-based hardening accelerators include triphenylphosphine, phosphonium borate compounds, tetraphenylphosphonium tetraphenylborate, n-butylphosphonium tetraphenylborate, tetrabutylphosphonium decanoate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, and butyltriphenylphosphonium thiocyanate.

Examples of amine-based hardening accelerators include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine (DMAP), benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, 1,8-diazabicyclo(5,4,0)-undecene, etc., preferably 4-dimethylaminopyridine.

Examples of imidazole-based hardening accelerators include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole trimellitate, 1-cyanoethyl-2-phenylimidazole trimellitate, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s -triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazolyl isocyanuric acid adduct Imidazole compounds such as cyanuric acid adducts, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, 2-phenylimidazoline, and adducts of imidazole compounds with epoxy resins.

As the imidazole-based hardening accelerator, a commercially available product may be used, for example, "P200-H50" manufactured by Mitsubishi Chemical Corporation.

Examples of guanidine-based hardening accelerators include dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1- ,5,7-triazabicyclo[4.4.0]dec-5-ene, 1-methylbiguanidine, 1-ethylbiguanidine, 1-n-butylbiguanidine, 1-n-octadecylbiguanidine, 1,1-dimethylbiguanidine, 1,1-diethylbiguanidine, 1-cyclohexylbiguanidine, 1-allylbiguanidine, 1-phenylbiguanidine, 1-(o-tolyl)biguanidine, etc.

Examples of metal hardening accelerators include organic metal complexes or organic metal salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of the organometallic complex include organic cobalt complexes such as cobalt (II) acetylacetonate and cobalt (III) acetylacetonate, organic copper complexes such as copper (II) acetylacetonate, organic zinc complexes such as zinc (II) acetylacetonate, organic iron complexes such as iron (III) acetylacetonate, organic nickel complexes such as nickel (II) acetylacetonate, and organic manganese complexes such as manganese (II) acetylacetonate. Examples of the organic metal salt include zinc octylate, tin octylate, zinc naphthenate, cobalt naphthenate, tin stearate, zinc stearate, and the like.

When the resin composition contains (D) a hardening accelerator, the content of the (D) hardening accelerator is not particularly limited when the "non-volatile component" in the resin composition is 100% by mass, but is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, further preferably 0.05% by mass or more, and particularly preferably 0.1% by mass or more. The upper limit is preferably 2% by mass or less, more preferably 1% by mass or less, further preferably 0.5% by mass or less, and particularly preferably 0.2% by mass or less.

When the resin composition contains (D) a hardening accelerator, the content of the (D) hardening accelerator is not particularly limited when the "resin component" in the resin composition is 100% by mass, but is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, even more preferably 0.1% by mass or more, and particularly preferably 0.5% by mass or more. The upper limit is preferably 5% by mass or less, more preferably 2% by mass or less, even more preferably 1% by mass or less, and particularly preferably 0.6% by mass or less.

<(E) Organic solvent> The resin composition of the present invention may further contain (E) an organic solvent as an optional volatile component.

Examples of organic solvents include ketone solvents such as acetone, methyl ethyl ketone, and cyclohexanone; ester solvents such as ethyl acetate, butyl acetate, cellulose acetate, propylene glycol monomethyl ether acetate, carbitol acetate, ethyl diglycol acetate, and γ-butyrolactone; carbitol solvents such as cellulose and butyl carbitol; aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, and trimethylbenzene; amide solvents such as dimethylformamide, dimethylacetamide (DMAc), and N-methylpyrrolidone; alcohol solvents such as methanol, ethanol, and 2-methoxypropanol; hydrocarbon solvents such as cyclohexane and methylcyclohexane. The organic solvent may be used alone or in combination of two or more in any ratio.

<(F) Other additives> In addition to the above-mentioned components, the resin composition may further contain other additives as arbitrary components. Examples of such additives include organic fillers, thickeners, defoamers, leveling agents, adhesion agents, polymerization initiators, flame retardants, etc. Such additives may be used alone or in combination of two or more. The content of each additive may be appropriately set by those skilled in the art.

<Manufacturing method of resin composition> In one embodiment, the resin composition of the present invention can be manufactured by a method including, for example, adding (A) epoxy resin, (B) hardener, (C) inorganic filler, (D) hardening accelerator as needed, (E) organic solvent as needed, and (F) other additives as needed in a reaction container in any order and/or partially or all at the same time and mixing to obtain the resin composition.

In the above steps, the temperature of the process of adding each component can be appropriately set, and the process of adding each component can also be temporarily or always heated and/or cooled. The process of adding each component can also be stirred or vibrated. After the above steps, it is preferred to further include a step of stirring the resin composition using a stirring device such as a mixer and uniformly dispersing it.

<Characteristics of Resin Composition> The resin composition of the present invention comprises (A) epoxy resin, (B) hardener and (C) inorganic filler. Since the component (B) comprises (B-1) active ester resin with a softening point of 100°C or less, (B-2) bifunctional active ester resin or (B-3) active ester resin with a molecular weight of 1,000 or less, a hardened material with reduced dielectric properties and suppressed flow marks can be obtained. In addition, according to the resin composition of the present invention, in one embodiment, a hardened material can be obtained that can maintain adhesion to semiconductor chips for a long time and has an excellent storage elastic modulus.

Regarding the low dielectric property, which is one of the characteristics of the cured product of the resin composition of the present invention, in one embodiment, for example, the dielectric tangent (tanδ) of the cured product obtained by thermally curing the resin composition measured by the Fabry-Pérot method (measurement frequency 79 GHz) is preferably 0.01 or less, more preferably 0.005 or less, still more preferably 0.004 or less, and particularly preferably 0.003 or less. The lower limit of the dielectric tangent is not particularly limited, but can be 0.001 or more, 0.0001 or more, 0.00001 or more, etc.

One of the characteristics of the cured resin composition of the present invention in one embodiment is that it can maintain adhesion to a semiconductor chip for a long time. For example, after a resin composition layer formed by the resin composition is compression-molded on a silicon wafer and thermally cured, even when subjected to a high temperature and high humidity environment test (HAST) for 100 hours at 130°C and 85%RH, the interface between the cured resin composition layer and the underlying silicon wafer does not peel off.

One of the characteristics of the cured product of the resin composition of the present invention in one embodiment is the excellent storage modulus, for example, the storage modulus of the layered cured product obtained by thermally curing the resin composition at 25°C measured at a frequency of 1 Hz and a heating rate of 5°C/min is preferably 40 GPa or less, more preferably 30 GPa or less, and even more preferably 25 GPa or less. The lower limit of the storage modulus is not particularly limited, but may be 10 GPa or more, 1 GPa or more, 0.1 GPa or more, etc.

In one embodiment, even if the resin composition of the present invention is compressed and formed into a resin composition layer, no flow marks occur on the surface of the resin composition layer after heating at 150°C for 60 minutes. In one embodiment, the resin composition of the present invention has a liquid property with fluidity at 25°C.

<Application of resin composition> The cured resin composition of the present invention is useful for the sealing layer and insulating layer of semiconductors due to the above advantages. Therefore, the resin composition can be used as a resin composition for semiconductor sealing or insulating layer.

For example, the resin composition of the present invention can be preferably used as a resin composition for forming an insulating layer of a semiconductor chip package (resin composition for insulating layer of semiconductor chip package) and a resin composition for forming an insulating layer of a circuit substrate (including a printed wiring board) (resin composition for insulating layer of a circuit substrate).

For example, the resin composition of the present invention can be preferably used as a resin composition for sealing a semiconductor chip in a semiconductor chip package (resin composition for semiconductor chip sealing).

Examples of semiconductor chip packages that can be applied with a sealing layer or an insulating layer formed by the cured product of the resin composition of the present invention include FC-CSP, MIS-BGA packaging, BTS-BGA packaging, fan-out WLP (wafer-level packaging), fan-in WLP, fan-out PLP (panel-level packaging), fan-in PLP, etc.

Furthermore, the resin composition of the present invention can be used as an underfill material, for example, as a material for MUF (Molding Under Filling) used after a semiconductor chip is connected to a substrate.

Furthermore, the resin composition of the present invention can be used in a wide range of resin compositions such as resin sheets, prepreg sheets and other thin-sheet lamination materials, liquid materials such as resin inks such as solder resists, die bonding materials, via embedding resins, and component embedding resins.

<Resin sheet> The resin sheet of the present invention comprises a support and a resin composition layer disposed on the support. The resin composition layer is a layer comprising the resin composition of the present invention, and is usually formed of a resin composition.

The thickness of the resin composition layer is preferably 600 μm or less, more preferably 500 μm or less, from the viewpoint of thinning. The lower limit of the thickness of the resin composition layer is preferably 1 μm or more, 5 μm or more, more preferably 10 μm or more, further preferably 50 μm or more, and particularly preferably 100 μm or more.

The thickness of the cured product obtained by curing the resin composition layer is preferably 1 μm or more, 5 μm or more, more preferably 10 μm or more, further preferably 50 μm or more, and particularly preferably 100 μm or more.

Examples of the support include films made of plastic materials, metal foils, and release paper, and films made of plastic materials and metal foils are preferred.

When a film made of a plastic material is used as a support, examples of the plastic material include polyesters such as polyethylene terephthalate (hereinafter sometimes referred to as "PET") and polyethylene naphthalate (hereinafter sometimes referred to as "PEN"); polycarbonate (hereinafter sometimes referred to as "PC"); acrylic polymers such as polymethyl methacrylate (hereinafter sometimes referred to as "PMMA"); cyclic polyolefin; triacetyl cellulose (hereinafter sometimes referred to as "TAC"); polyether sulfide (hereinafter sometimes referred to as "PES"); polyether ketone; polyimide, etc. Among them, polyethylene terephthalate and polyethylene naphthalate are preferred, and inexpensive polyethylene terephthalate is particularly preferred.

When a metal foil is used as a support, the metal foil is preferably copper foil, aluminum foil, etc. Among them, copper foil is preferred. The copper foil may be a foil made of copper alone, or a foil made of an alloy of copper and other metals (such as tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.).

The support body may also be subjected to a treatment such as a matte treatment, a corona treatment, an antistatic treatment, etc. on the surface that is bonded to the resin composition layer.

Furthermore, as a support body, a support body with a release layer having a release layer on the surface bonded to the resin composition layer can also be used. Examples of release agents used in the release layer of the support body with a release layer include at least one release agent selected from the group consisting of alkyd resins, polyolefin resins, urethane resins, and silicone resins. Examples of commercially available release agents include alkyd resin release agents such as "SK-1", "AL-5", and "AL-7" manufactured by LINTEC. Examples of the support body with a release layer include "LUMIRROR T60" manufactured by Toray Industries, "PUREX" manufactured by Teijin, and "UNIPEEL" manufactured by UNITIKA.

The thickness of the support is preferably in the range of 5 μm to 75 μm, more preferably in the range of 10 μm to 60 μm. When a support with a release layer is used, the thickness of the support with a release layer is preferably in the above range.

The resin sheet can be manufactured by, for example, applying the resin composition onto a support using a coating device such as a die coater. Alternatively, if necessary, the resin composition can be dissolved in an organic solvent to prepare a resin varnish, and the resin sheet can be manufactured by applying the resin varnish. By using a solvent, the viscosity can be adjusted to improve the coating property. When using a resin varnish, the resin varnish is usually dried after application to form a resin composition layer.

Drying can be carried out by known methods such as heating and hot air blowing. The drying condition is to dry until the organic solvent content in the resin composition layer is usually 10 mass% or less, preferably 5 mass% or less. Although it varies with the boiling point of the organic solvent in the resin varnish, for example, when a resin varnish containing 30 mass% to 60 mass% of organic solvent is used, the resin composition layer can be formed by drying at 50°C to 150°C for 3 minutes to 10 minutes.

The resin sheet may include any layer other than the support and the resin component layer as required. For example, in the resin sheet, a protective film depending on the support may be provided on the surface of the resin component layer that is not bonded to the support (i.e., the surface opposite to the support). The thickness of the protective film may be, for example, 1 μm to 40 μm. The protective film can prevent dirt from adhering to or scratching the surface of the resin component layer. When the resin sheet has a protective film, the resin sheet can be used by removing the protective film. The resin sheet can also be rolled into a roll for storage.

The resin sheet can be preferably used in the manufacture of semiconductor chip packages to form an insulating layer (resin sheet for insulating semiconductor chip packages). For example, the resin sheet can be used to form an insulating layer of a circuit substrate (resin sheet for insulating layer of a circuit substrate). Examples of packages using such substrates include FC-CSP, MIS-BGA packages, and ETS-BGA packages.

Furthermore, the resin sheet can be preferably used to seal a semiconductor chip (resin sheet for semiconductor chip packaging). Examples of applicable semiconductor chip packages include fan-out WLP, fan-in WLP, fan-out PLP, fan-in PLP, and the like.

In addition, the resin sheet can be used as a material for MUF used after the semiconductor chip is connected to the substrate.

Furthermore, the resin sheet can be used in a wide range of other applications requiring high insulation reliability. For example, the resin sheet can be preferably used to form an insulation layer of a circuit substrate such as a printed wiring board.

<Circuit board> The circuit board of the present invention includes an insulating layer formed by a cured product of the resin composition of the present invention. The circuit board can be manufactured by, for example, a manufacturing method including the following steps (1) and (2). (1) A step of forming a resin composition layer on a substrate. (2) A step of thermally curing the resin composition layer to form an insulating layer.

In step (1), a substrate is prepared. Examples of the substrate include glass epoxy substrates, metal substrates (stainless steel or cold-pressed rolled steel (SPCC)), polyester substrates, polyimide substrates, BT resin substrates, thermosetting polyphenylene ether substrates, and the like. The substrate may also have a metal layer such as copper foil on its surface as part of the substrate. For example, a substrate having a first metal layer and a second metal layer that can be peeled off on both surfaces may be used. When using such substrates, a conductive layer that serves as a wiring layer that can function as circuit wiring is usually formed on the surface of the second metal layer opposite to the first metal layer. An example of a substrate having such a metal layer is an ultra-thin copper foil "Micro Thin" with a carrier copper foil manufactured by Mitsui Metals & Mining Co., Ltd.

Furthermore, a conductive layer may be formed on the surface of one or both of the substrates. In the following description, a component including a substrate and a conductive layer formed on the surface of the substrate is sometimes referred to as a "substrate with a wiring layer". Examples of conductive materials contained in the conductive layer include materials including one or more metals selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium. As the conductive material, a single metal may be used, or an alloy may be used. Examples of alloys include alloys of two or more metals selected from the above group (e.g., nickel-chromium alloy, copper-nickel alloy, and copper-titanium alloy). Among them, from the viewpoint of wide availability, cost, and ease of patterning of the conductor layer formation, chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper as a single metal, and nickel-chromium alloy, copper-nickel alloy, and copper-titanium alloy as an alloy are preferred. Among them, chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper as a single metal, and nickel-chromium alloy are more preferred, and copper as a single metal is particularly preferred.

The conductor layer may also be patterned, for example, in order to function as a wiring layer. In this case, the line (circuit width)/spacing (spacing between circuits) ratio of the conductor layer is not particularly limited, but is preferably 20/20 μm or less (i.e., spacing is 40 μm or less), more preferably 10/10 μm or less, still more preferably 5/5 μm or less, still more preferably 1/1 μm or less, and particularly preferably 0.5/0.5 μm or more. The spacing does not necessarily have to be the same throughout the conductor layer. The minimum spacing of the conductor layer may be, for example, 40 μm or less, 36 μm or less, or 30 μm or less.

The thickness of the conductor layer depends on the design of the circuit substrate, but is preferably 3 μm to 35 μm, more preferably 5 μm to 30 μm, even more preferably 10 μm to 20 μm, and particularly preferably 15 μm to 20 μm.

The conductive layer can be formed by a method comprising the following steps: a step of laminating a dry film (photosensitive resist film) on a substrate; a step of exposing and developing the dry film under specific conditions using a photomask to form a pattern to obtain a patterned dry film; a step of forming a conductive layer by a coating method such as an electrolytic coating method using the developed patterned dry film as a coating mask; and a step of peeling off the patterned dry film. As the dry film, a photosensitive dry film formed of a photoresist composition can be used, for example, a dry film formed of a resin such as a novolac resin or an acrylic resin can be used. The lamination conditions of the substrate and the dry film are the same as the lamination conditions of the substrate and the resin sheet described later. The stripping of the dry film can be carried out using an alkaline stripping liquid such as sodium hydroxide solution.

After preparing the substrate, a resin composition layer is formed on the substrate. When forming the conductor layer on the surface of the substrate, the resin composition layer is preferably formed in a manner that the conductor layer is embedded in the resin composition layer.

The resin composition layer is formed, for example, by laminating a resin sheet and a substrate. The lamination can be performed, for example, by heat-pressing the resin sheet to the substrate from the side of the support so that the resin composition layer is attached to the substrate. Examples of the member for heat-pressing the resin sheet to the substrate (hereinafter sometimes referred to as the "heat-pressing member") include, for example, a heated metal plate (SUS mirror plate, etc.) or a metal roller (SUS roller, etc.). In addition, the preferred heat-pressing member is not directly pressed on the resin sheet, but is pressed through an elastic material such as heat-resistant rubber in a manner that allows the resin sheet to fully follow the surface irregularities of the substrate.

The lamination of the substrate and the resin sheet can also be performed by, for example, a vacuum lamination method. In the vacuum lamination method, the heating and pressing temperature is preferably in the range of 60°C to 160°C, more preferably in the range of 80°C to 140°C. The heating and pressing pressure is preferably in the range of 0.098MPa to 1.77MPa, more preferably in the range of 0.29MPa to 1.47MPa. The heating and pressing time is preferably in the range of 20 seconds to 400 seconds, more preferably in the range of 30 seconds to 300 seconds. Lamination is preferably performed under reduced pressure conditions with a pressure of less than 13hPa.

After lamination, the laminated resin sheet can be smoothed by, for example, applying pressure to the heat-pressing member from the support body side under normal pressure (atmospheric pressure). The pressurizing conditions for the smoothing treatment can be the same as the heat-pressing conditions for the lamination described above. In addition, lamination and smoothing treatment can be performed continuously using a vacuum laminator.

The resin composition layer can be formed by, for example, compression molding. The molding conditions can be the same as those of the method for forming the resin composition layer in the step of forming the sealing layer of the semiconductor chip package described later.

After forming a resin composition layer on the substrate, the resin composition layer is thermally cured to form an insulating layer. The thermal curing conditions of the resin composition layer vary with the type of the resin composition, but the curing temperature is generally in the range of 120°C to 240°C (preferably in the range of 150°C to 220°C, and more preferably in the range of 170°C to 200°C), and the curing time is preferably in the range of 5 minutes to 120 minutes (preferably 10 minutes to 100 minutes, and even more preferably 15 minutes to 90 minutes).

Before the resin composition layer is heat-hardened, the resin composition layer may be preheated at a temperature lower than the hardening temperature. For example, before the resin composition layer is heat-hardened, the resin composition layer may be preheated at a temperature of usually 50°C or higher and lower than 120°C (preferably 60°C or higher and 110°C or lower, more preferably 70°C or higher and 110°C or lower) for usually 5 minutes or more (preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes).

As described above, a circuit substrate having an insulating layer can be manufactured. In addition, the manufacturing method of the circuit substrate can further include any steps. For example, when a circuit substrate is manufactured using a resin sheet, the manufacturing method of the circuit substrate can include the step of peeling off the support body of the resin sheet. The support body can be peeled off before the resin component layer is thermally cured, and can also be peeled off after the resin component layer is thermally cured.

The manufacturing method of the circuit substrate may include a step of grinding the surface of the insulating layer after forming the insulating layer. The grinding method is not particularly limited. For example, a flat grinding disc may be used to grind the surface of the insulating layer.

The manufacturing method of the circuit substrate may also include, for example, the step (3) of connecting the conductor layer between layers, that is, the step of perforating the insulating layer. In this way, holes such as perforations and through holes can be formed in the insulating layer. Examples of the method of forming the perforations include laser irradiation, etching, mechanical drilling, etc. The size or shape of the perforations can be appropriately determined according to the possible design of the circuit substrate. In addition, step (3) can also be performed by grinding or grinding the insulating layer to connect between layers.

After the through-hole is formed, it is preferred to perform a step of removing the slag in the through-hole. This step is sometimes called a deslagging step. For example, when a conductive layer is formed on an insulating layer by a coating step, a wet deslagging treatment can also be performed on the through-hole. Also, when a conductive layer is formed on an insulating layer by a sputtering step, a dry deslagging step such as a plasma treatment step can also be performed. Furthermore, the insulating layer can also be roughened by a deslagging step.

Furthermore, before forming the conductive layer on the insulating layer, the insulating layer may be subjected to a roughening treatment. According to the roughening treatment, the surface of the insulating layer including the through-hole can be generally roughened. The roughening treatment may be performed by either a dry roughening treatment or a wet roughening treatment. An example of a dry roughening treatment is a plasma treatment. Another example of a wet roughening treatment is a method of sequentially performing a swelling treatment using a swelling liquid, a roughening treatment using an oxidizing agent, and a neutralization treatment using a neutralizing liquid.

After forming the perforations, a conductive layer can also be formed on the insulating layer. By forming a conductive layer at the location where the perforations are formed, the newly formed conductive layer is connected to the conductive layer on the surface of the substrate to achieve inter-layer connection. Examples of methods for forming the conductive layer include plating, sputtering, evaporation, etc., among which plating is preferred. In a preferred embodiment, plating is performed on the surface of the insulating layer by an appropriate method such as a semi-additive method and a full-additive method to form a conductive layer with a desired wiring pattern. Furthermore, when the support in the resin sheet is a metal foil, a conductive layer with a desired wiring pattern can be formed by a subtractive method. The material of the formed conductive layer can be a single metal or an alloy. The conductive layer may have a single-layer structure or a multi-layer structure including two or more layers made of different types of materials.

Here, an example of an implementation form of forming a conductive layer on an insulating layer is described in detail. A coating seed layer is formed on the surface of the insulating layer by electroless plating. Next, a mask pattern is formed on the formed coating seed layer to expose a portion of the coating seed layer corresponding to the desired wiring pattern. After an electrolytic coating layer is formed on the exposed coating seed layer by electrolytic plating, the mask pattern is removed. Subsequently, the unnecessary coating seed layer is removed by etching or the like, and a conductive layer having the desired wiring pattern can be formed. Furthermore, when forming the conductive layer, the dry film used to form the mask pattern is the same as the above-mentioned dry film.

The method for manufacturing a circuit substrate may also include a step (4) of removing the substrate. By removing the substrate, a circuit substrate having an insulating layer and a conductor layer embedded in the insulating layer is obtained. The step (4) may be performed, for example, when a substrate having a strippable metal layer is used.

<Semiconductor chip package> The semiconductor chip package of the first embodiment of the present invention includes the above-mentioned circuit substrate and a semiconductor chip mounted on the circuit substrate. The semiconductor chip package can be manufactured by bonding the semiconductor chip to the circuit substrate.

The bonding conditions between the circuit board and the semiconductor chip can be any conditions that can connect the terminal electrodes of the semiconductor chip to the circuit wiring conductors of the circuit board. For example, the conditions used in flip-chip mounting of semiconductor chips can be used. And for example, the semiconductor chip and the circuit board can be bonded via an insulating adhesive.

An example of a bonding method is a method of pressing a semiconductor chip onto a circuit board. As pressing conditions, the pressing temperature is usually in the range of 120°C to 240°C (preferably 130°C to 200°C, and more preferably 140°C to 180°C), and the pressing time is usually in the range of 1 second to 60 seconds (preferably 5 seconds to 30 seconds).

Another example of the bonding method is to reflow the semiconductor chip onto the circuit board. The reflow condition can be set in the range of 120°C to 300°C.

After the semiconductor chip is bonded to the circuit substrate, the semiconductor chip may be filled with a mold underfill material. The above-mentioned resin composition or the above-mentioned resin sheet may be used as the mold underfill material.

The semiconductor chip package of the second embodiment of the present invention comprises a semiconductor chip and a hardened material of the aforementioned resin composition for sealing the semiconductor chip. In such semiconductor chip package, the hardened material of the resin composition usually functions as a sealing layer. The semiconductor chip package of the second embodiment is exemplified by a fan-out WLP.

The manufacturing method of such semiconductor chip package includes: (A) a step of laminating a temporary fixing film on a substrate, (B) a step of temporarily fixing a semiconductor chip on the temporary fixing film, (C) a step of forming a sealing layer on the semiconductor chip, (D) a step of peeling the substrate and the temporary fixing film from the semiconductor chip, (E) a step of forming a redistribution forming layer as an insulating layer on the surface of the semiconductor chip from which the substrate and the temporary fixing film have been peeled, (F) a step of forming a redistribution layer as a conductive layer on the redistribution forming layer, and (G) a step of forming a solder resist layer on the redistribution layer. Furthermore, the manufacturing method of the aforementioned semiconductor chip package may also include: (H) the step of cutting a plurality of semiconductor chip packages into individual semiconductor chip packages for singulation.

(Step (A)) Step (A) is a step of laminating a temporary fixing film on a substrate. The lamination conditions of the substrate and the temporary fixing film are the same as the lamination conditions of the substrate and the resin sheet in the circuit board manufacturing method.

Examples of the substrate include silicon wafers; glass wafers; glass substrates; metal substrates such as copper, titanium, stainless steel, and cold-pressed rolled steel (SPCC); substrates such as FR-4 substrates in which epoxy resin is infiltrated into glass fibers and then heat-cured; substrates made of dimaleimide triazine resins such as BT resin, etc.

The temporary fixing film may be any material that can be peeled off from the semiconductor chip and can temporarily fix the semiconductor chip. Examples of commercially available products include "RIVA ALPHA" manufactured by Nitto Denko Corporation.

(Step (B)) Step (B) is a step of temporarily fixing the semiconductor chip on the temporary fixing film. The temporary fixing of the semiconductor chip can be performed using a device such as a flip chip bonding machine or a die bonding machine. The layout and number of semiconductor chips can be appropriately set according to the shape and size of the temporary fixing film, the production number of the target semiconductor chip package, etc. For example, the semiconductor chips can be arranged in a matrix of multiple rows and multiple columns and temporarily fixed.

(Step (C)) Step (C) is a step of forming a sealing layer on the semiconductor chip. The sealing layer is formed by hardening the above-mentioned resin composition. The sealing layer is usually formed by a method comprising the steps of forming a resin composition layer on the semiconductor chip and thermally hardening the resin composition layer to form the sealing layer.

Taking advantage of the excellent compression molding properties of the resin composition, the resin composition layer is preferably formed by compression molding. In the compression molding method, a semiconductor chip and a resin composition are usually placed in a mold, and pressure and heat are applied to the resin composition in the mold as needed to form a resin composition layer covering the semiconductor chip.

The specific operation of the compression molding method is as follows. As a mold for compression molding, an upper mold and a lower mold are prepared. A resin composition is coated on the semiconductor chip temporarily fixed on the temporary fixing film as described above. The semiconductor chip coated with the resin composition is installed on the lower mold together with the substrate and the temporary fixing mold. Subsequently, the upper mold and the lower mold are fixed, and heat and pressure are applied to the resin composition for compression molding.

The specific operation of the compression molding method is as follows. As a mold for compression molding, an upper mold and a lower mold are prepared. A resin composition is placed on the lower mold. A semiconductor chip is mounted on the upper mold together with a substrate and a temporary fixed mold. Subsequently, the upper mold and the lower mold are fixed in a manner such that the resin composition placed on the lower mold is connected to the semiconductor chip mounted on the upper mold, and compression molding is performed by applying heat and pressure.

The molding conditions vary with the composition of the resin composition, and appropriate conditions are adopted in a manner that can achieve good sealing. For example, the mold temperature during molding is preferably a temperature that allows the resin composition to exert excellent compression molding properties, preferably 80°C or higher, more preferably 100°C or higher, particularly preferably 120°C or higher, preferably 200°C or lower, more preferably 170°C or lower, and particularly preferably 150°C or lower. In addition, the pressure applied during molding is preferably 1MPa or higher, more preferably 3MPa or higher, particularly preferably 5MPa or higher, preferably 50MPa or lower, more preferably 30MPa or lower, and particularly preferably 20MPa or lower. The curing time is preferably 1 minute or more, more preferably 2 minutes or more, particularly preferably 5 minutes or more, preferably 60 minutes or less, more preferably 30 minutes or less, particularly preferably 20 minutes or less. Usually, after the resin composition layer is formed, the mold is removed. The mold can be removed before the resin composition layer is thermally hardened, or after thermally hardened.

The formation of the resin composition layer can be performed by laminating a resin sheet and a semiconductor chip. For example, the resin composition layer of the resin sheet and the semiconductor chip can be formed on the semiconductor chip by heating and pressing. The lamination of the resin sheet and the semiconductor chip can usually be performed in the same manner as the lamination of the resin sheet and the substrate in the manufacturing method of the circuit board, using the semiconductor chip instead of the substrate.

After forming a resin composition layer on a semiconductor chip, the resin composition layer is thermally cured to obtain a sealing layer covering the semiconductor chip. In this way, the semiconductor chip is sealed using the cured resin composition. The thermal curing conditions of the resin composition layer can be the same as the thermal curing conditions of the resin composition layer in the method for manufacturing a circuit board. Furthermore, before thermally curing the resin composition layer, the resin composition layer can be subjected to a preheating treatment at a temperature lower than the curing temperature. The treatment conditions of the preheating treatment can be the same as the preheating treatment in the method for manufacturing a circuit board.

(Step (D)) Step (D) is a step of peeling the substrate and the temporary fixing film from the semiconductor chip. The peeling method is expected to adopt an appropriate method corresponding to the material of the temporary fixing film. As an example of the peeling method, there is a method of heating, foaming or expanding the temporary fixing film and peeling it off. Another example of the peeling method is a method of irradiating the temporary fixing film with ultraviolet rays through the substrate to reduce the adhesion of the temporary fixing film and peeling it off.

In the method of heating, foaming or expanding the temporary fixing film and peeling it off, the heating condition is usually 100℃~250℃ for 1 second to 90 seconds or 5 minutes to 15 minutes. In the method of irradiating ultraviolet rays to reduce the adhesion of the temporary fixing film and peeling it off, the irradiation amount of ultraviolet rays is usually 10mJ/ ^cm2 ~1000mJ/ ^cm2 .

(Step (E)) Step (E) is a step of forming a redistribution layer as an insulating layer on the surface of the semiconductor chip from which the substrate and the temporary fixing film have been peeled off.

The material of the redistribution forming layer can be any material having insulation properties. Among them, photosensitive resins and thermosetting resins are preferred from the viewpoint of ease of manufacturing semiconductor chip packaging. As the thermosetting resin, the resin composition of the present invention can be used.

After the redistribution formation layer is formed, through holes may be formed in the redistribution formation layer in order to provide interlayer connection between the semiconductor chip and the redistribution layer.

In the perforation forming method when the material of the redistribution forming layer is a photosensitive resin, active energy rays are usually irradiated on the surface of the redistribution forming layer through a mask pattern to photoharden the redistribution forming layer in the irradiated portion. Examples of active energy rays include ultraviolet rays, visible light, electron beams, X-rays, etc., and ultraviolet rays are particularly preferred. The irradiation amount and irradiation time of ultraviolet rays can be appropriately set according to the photosensitive resin. As the exposure method, for example, a contact exposure method in which a mask pattern is closely attached to the redistribution forming layer and exposed, and a non-contact exposure method in which a mask pattern is not closely attached to the redistribution forming layer and exposed using parallel light rays can be used.

After the redistribution forming layer is photocured, the redistribution forming layer is developed to remove the unexposed portion, thereby forming a perforation. The development may be performed by either wet development or dry development. Examples of the developing method include an immersion method, a liquid coating method, a spray method, a brush coating method, and an extrusion coating method. From the viewpoint of resolution, the liquid coating method is preferred.

When the material of the redistribution forming layer is a thermosetting resin, the method of forming the through hole is, for example, laser irradiation, etching, mechanical drilling, etc. Among them, laser irradiation is preferred. Laser irradiation can be performed using a suitable laser processing machine using a carbon dioxide laser, UV-YAG laser, excimer laser, etc. as a light source.

The shape of the perforation is not particularly limited, and is generally set to be circular (slightly circular). The top diameter of the perforation is preferably 50 μm or less, more preferably 30 μm or less, and even more preferably 20 μm or less, preferably 3 μm or more, more preferably 10 μm or more, and even more preferably 15 μm or more. Here, the top diameter of the perforation refers to the opening diameter of the perforation on the surface of the redistribution formation layer.

(Step (F)) Step (F) is a step of forming a redistribution layer as a conductive layer on the redistribution formation layer. The method of forming the redistribution layer on the redistribution formation layer is the same as the method of forming a conductive layer on the insulating layer in the manufacturing method of the circuit board. Alternatively, steps (E) and (F) may be repeated to alternately stack (build up) the redistribution layer and the redistribution formation layer.

(Step (G)) Step (G) is a step of forming a solder resist layer on the redistribution layer. The material of the solder resist layer can be any material having insulating properties. Among them, photosensitive resins and thermosetting resins are preferred from the perspective of ease of manufacturing semiconductor chip packaging. As a thermosetting resin, the resin composition of the present invention can be used.

Furthermore, in step (G), bump processing can be performed to form bumps as needed. The bump processing can be performed by solder balls, solder plating, etc. Furthermore, the formation of through holes in the bump processing can be performed in the same way as in step (E).

(Step (H)) The method for manufacturing a semiconductor chip package may include step (H) in addition to steps (A) to (G). Step (H) is a step of cutting a plurality of semiconductor chip packages into individual semiconductor chip packages for singulation. The method for cutting a semiconductor chip package into individual semiconductor chip packages is not particularly limited.

<Semiconductor device> The semiconductor device has a semiconductor chip package. Examples of semiconductor devices include various semiconductor devices used in electrical products (such as computers, mobile phones, smart phones, tablet devices, wearable devices, digital cameras, medical devices, and televisions) and vehicles (such as motorcycles, cars, trains, ships, and airplanes). [Example]

The present invention is specifically described below by way of examples. The present invention is not limited to the examples. In addition, in the following, "parts" and "%" indicating amounts mean "parts by mass" and "% by mass" respectively unless otherwise specified.

<Synthesis Example 1: Synthesis of Active Ester Resin> Into a reaction vessel, add 288 parts by mass of 1-naphthol and 1400 parts by mass of toluene, and dissolve while replacing the pressure in the container with nitrogen. Then add 203 parts by mass of isophthalic acid dichloride and dissolve. While blowing nitrogen into the container, add 400 g of a 20% aqueous sodium hydroxide solution dropwise over 3 hours. At this time, the temperature in the system is controlled to be below 60°C. Then, stir for 1 hour to react. After the reaction is completed, separate the reactants and remove the aqueous layer. Repeat this operation until the pH of the aqueous layer reaches 7, and dilute toluene and the like under heating and reduced pressure to obtain an active ester resin (the compound of the above formula (3); molecular weight 418.4). The functional group equivalent weight of the active ester resin is 209 g/equivalent and the softening point is 78°C.

<Example 1> 2 parts of glycidylamine epoxy resin ("EP-3980S" manufactured by ADEKA, epoxy equivalent 115 g/eq.), 7 parts of alicyclic epoxy resin ("CELLOXIDE 2021P" manufactured by DAICEL, epoxy equivalent 136 g/eq.), 5 parts of active ester resin (softening point 78°C) obtained in Synthesis Example 1, 5 parts of acid anhydride curing agent ("MH-700" manufactured by Shin Nippon Rika Chemical Co., Ltd.), and silicon oxide A (average particle size 9 μm, specific surface area 5.0 ^m2) were mixed with a mixer. /g, surface treated with KBM573 (manufactured by Shin-Etsu Chemical Co., Ltd.) 140 parts, and a curing accelerator ("1B2PZ" manufactured by Shikoku Chemical Co., Ltd., 1-benzyl-2-phenylimidazole) 0.1 parts were uniformly dispersed to obtain a resin composition.

<Example 2> A resin composition was obtained in the same manner as in Example 1 except that 170 parts of aluminum oxide A (average particle size 10 μm, specific surface area 0.3 m ² /g, surface treated with KBM5783 (manufactured by Shin-Etsu Chemical)) was used instead of 140 parts of silicon oxide A.

<Example 3> A resin composition was obtained in the same manner as in Example 1 except that 140 parts of silica B (average particle size 9 μm, specific surface area 5.0 m ² /g, surface treated with KBM503 (manufactured by Shin-Etsu Chemical)) was used instead of 140 parts of silica A.

<Example 4> Except that the amount of the active ester resin (softening point 78°C) obtained in Synthesis Example 1 was changed from 5 parts to 3 parts, and the amount of the acid anhydride hardener ("MH-700" manufactured by Shin Nippon Chemical) was changed from 5 parts to 7 parts, the same operation as in Example 1 was performed to obtain a resin composition.

<Example 5> Except that the amount of the active ester resin (softening point 78°C) obtained in Synthesis Example 1 was changed from 5 parts to 7 parts, and the amount of the acid anhydride hardener ("MH-700" manufactured by Shin Nippon Rika) was changed from 5 parts to 3 parts, the same operation as in Example 1 was performed to obtain a resin composition.

<Comparative Example 1> Except that the active ester resin (softening point 78°C) obtained in Synthesis Example 1 was not used and the amount of anhydride hardener ("MH-700" manufactured by Shin Nippon Chemical) used was changed from 5 parts to 10 parts, the same operation as in Example 1 was performed to obtain a resin composition.

<Comparative Example 2> Except that 5 parts of a commercially available active ester resin ("HPC-8000" manufactured by DIC Corporation, softening point 152°C) were used instead of 5 parts of the active ester resin obtained in Synthesis Example 1 (softening point 78°C), the same operation as in Example 1 was performed to obtain a resin composition.

<Test Example 1: Evaluation of the adhesion of silicon wafers after high temperature and high humidity environment test (HAST)> On a 12-inch silicon wafer, the resin composition prepared in the embodiment and the comparative example was compressed and molded using a compression molding device (mold temperature: 130°C, pressure: 6MPa, curing time: 10 minutes) to form a resin composition layer with a thickness of 300μm. Subsequently, the resin composition layer was heated at 180°C for 90 minutes to thermally harden the resin composition layer to prepare a sample. For the prepared samples, a high temperature and high humidity environment test was carried out for 100 hours at 130°C and 85%RH using a highly accelerated life test device ("PM422" manufactured by Kusumoto Chemicals Co., Ltd.). After the test, check whether the interface between the hardened material and the base silicon wafer is peeled. If there is no peeling between the hardened material and the base silicon wafer, the evaluation is "○", and if there is peeling between the hardened material and the base silicon wafer, the evaluation is "×".

<Test Example 2: Measurement of Dielectric Tangent> On a 12-inch silicon wafer that had been subjected to mold release, the resin composition prepared in the embodiment and the comparative example was compressed and molded using a compression molding device (mold temperature: 130°C, pressure: 6MPa, curing time: 10 minutes) to form a resin composition layer with a thickness of 300μm. Subsequently, the resin composition was peeled off from the silicon wafer that had been subjected to mold release, and the resin composition was heated at 180°C for 90 minutes to thermally cure the resin composition to produce a sample. The dielectric tangent was measured at 79GHz using the Fabry-Perot method. The measurement was performed on 3 test pieces and the average value was calculated.

<Test Example 3: Determination of Storage Elastic Modulus> On a 12-inch silicon wafer that had been subjected to demolding, the resin composition prepared in the embodiment and the comparative example was compressed and molded using a compression molding device (mold temperature: 130°C, pressure: 6MPa, curing time: 10 minutes) to form a resin composition layer with a thickness of 300μm. Subsequently, the resin composition was peeled off from the silicon wafer that had been subjected to demolding, and heated at 180°C for 90 minutes to thermally cure the resin composition to produce a cured sample. The hardened material was cut into a test piece with a width of 7 mm and a length of 40 mm. The dynamic mechanical analysis was performed in the tensile mode using a dynamic mechanical analysis device DMS-6100 (manufactured by SEIKO INSTRUMENTS). After the test piece was mounted in the aforementioned device, the measurement was performed under the measurement conditions of a frequency of 1 Hz and a heating rate of 5°C/min. The storage elastic modulus (E') GPa value at 25°C was read during the measurement.

<Test Example 4: Evaluation of flow marks> On a 12-inch silicon wafer, the resin composition prepared in the embodiment and the comparative example was compressed and molded using a compression molding device (mold temperature: 130°C, pressure: 6MPa, curing time: 10 minutes) to form a resin composition layer with a thickness of 300μm. Subsequently, after heating at 150°C for 60 minutes, the flow marks on the surface of the resin composition layer were visually confirmed. The one with flow marks was evaluated as "×", and the one without flow marks was evaluated as "○".

<Test Example 5: Evaluation of the properties of the resin composition> The properties of the resin compositions prepared in the examples and comparative examples were evaluated. When the resin composition was in a fluid liquid state at 25°C, it was evaluated as "liquid", and when it was in a non-fluid clay state, it was evaluated as "clay".

The non-volatile components and usage amounts of the resin compositions of the Examples and Comparative Examples, as well as the measurement results and evaluation results of the Test Examples are shown in Table 1 below.

As shown in the above results, when components (B-1) to (B-3) are used as the (B) curing agent, a cured product with reduced dielectric properties and suppressed flow marks can be obtained.

Claims (17)

A resin composition comprising (A) an epoxy resin, (B) a hardener and (C) an inorganic filler, wherein the component (A) comprises a liquid epoxy resin, the component (B) comprises (B-1) an active ester resin having a softening point of 100° C. or less among bifunctional active ester resins represented by formula (1) and an acid anhydride hardener, and the content of the component (C) is 50% by mass or more when the non-volatile components in the resin composition are taken as 100% by mass,

[wherein, rings X, Y and Z each independently represent an aromatic ring which may further have a substituent selected from a halogen atom, an alkyl group, an alkenyl group, an alkoxy group, an alkylcarbonyl group, an aryl group, an aryloxy group, an arylcarbonyl group, an aralkyl group, an aromatic heterocyclic group and a non-aromatic heterocyclic group]. A resin composition comprising (A) an epoxy resin, (B) a hardener and (C) an inorganic filler, wherein the component (B) comprises (B-1) an active ester resin having a softening point of 100° C. or less among the bifunctional active ester resins represented by formula (1), the component (A) comprises a liquid epoxy resin, the content of the component (C) is 50% by mass or more when the non-volatile components in the resin composition are set to 100% by mass, and the content of the component (B-1) is 1% by mass to 20% by mass when the non-volatile components in the resin composition are set to 100% by mass. The dielectric tangent of the cured product obtained by heat curing the resin composition at 180°C for 90 minutes measured by the Fabry-Pérot method (measurement frequency 79 GHz) is less than 0.004.

[wherein, rings X, Y and Z each independently represent an aromatic ring which may further have a substituent selected from a halogen atom, an alkyl group, an alkenyl group, an alkoxy group, an alkylcarbonyl group, an aryl group, an aryloxy group, an arylcarbonyl group, an aralkyl group, an aromatic heterocyclic group and a non-aromatic heterocyclic group]. For example, in the resin composition of claim 1, the content of component (B-1) is 1% by mass to 50% by mass when the non-volatile components in the resin composition are set to 100% by mass. The resin composition of claim 1 or 2, wherein component (B) further comprises one or more hardeners selected from phenolic hardeners, naphthol hardeners, amine hardeners and anhydride hardeners. For example, in the resin composition of claim 1 or 2, the average particle size of component (C) is 1μm~40μm. In the resin composition of claim 1 or 2, the content of component (C) is 80% by mass or more when the non-volatile components in the resin composition are set to 100% by mass. The resin composition of claim 1 or 2 is liquid at 25°C. The resin composition of claim 1 or 2 is used to form an insulating layer for semiconductor chip packaging. The resin composition of claim 1 or 2 is used to form an insulating layer of a circuit substrate. The resin composition of claim 1 or 2 is used to seal a semiconductor chip in a semiconductor chip package. A hardened material, which is a hardened material of the resin composition as claimed in any one of claims 1 to 10. A resin sheet having a support and a resin composition layer disposed on the support and comprising a resin composition as described in any one of claims 1 to 10. A circuit substrate comprising an insulating layer formed by a cured product of a resin composition as described in any one of claims 1 to 10. A semiconductor chip package, comprising a circuit substrate as claimed in claim 13 and a semiconductor chip mounted on the circuit substrate. A semiconductor device having a semiconductor chip package as claimed in claim 14. A semiconductor chip package comprising a semiconductor chip and a hardened resin composition as described in any one of claims 1 to 10 for sealing the semiconductor chip. A semiconductor device having a semiconductor chip package as claimed in claim 16.