JP7484081B2 - Curable resin composition and electronic component device - Google Patents

Description

The present invention relates to a curable resin composition and an electronic component device.

In recent years, electronic devices have become smaller, lighter, and more powerful, leading to higher density packaging. As a result, the mainstream of electronic device devices is shifting from conventional pin insertion type packages to surface mount packages such as ICs (Integrated Circuits) and LSIs (Large Scale Integration).

Surface-mount packages have a different mounting method from conventional pin-insertion packages. That is, when attaching pins to a wiring board, in conventional pin-insertion packages, the pins are inserted into the wiring board and then soldered from the back side of the wiring board, so the package is not directly exposed to high temperatures. However, in surface-mount packages, the entire electronic component device is processed in a solder bath, reflow equipment, etc., so the package is directly exposed to the soldering temperature (reflow temperature). As a result, if the package absorbs moisture, the moisture expands rapidly during soldering, and the generated vapor pressure acts as a peeling stress, causing peeling between the insert such as the element or lead frame and the sealing material, which may cause package cracks and poor electrical characteristics. For this reason, there is a demand for the development of a sealing material that has excellent adhesion to the insert and, by extension, excellent solder heat resistance (reflow resistance).

In order to meet the above demands, for example, the use of silane coupling agents as modifiers for inorganic fillers contained in sealing materials has been considered. Specifically, the use of epoxy group-containing silane coupling agents or amino group-containing silane coupling agents (see, for example, Patent Document 1), the use of sulfur atom-containing silane coupling agents (see, for example, Patent Document 2), etc. have been considered.

Japanese Patent Application Laid-Open No. 11-147939 JP 2000-103940 A

However, the method using an epoxy group-containing silane coupling agent or an amino group-containing silane coupling agent may not be effective enough in improving adhesion to the metal on the surface of the lead frame. In addition, when a sulfur atom-containing silane coupling agent is used, there is a problem that the effect of improving adhesion to certain metals such as gold and silver is not sufficient.

In view of the above circumstances, the present invention aims to provide a curable resin composition that can provide a sealing structure that has excellent adhesion to metals and reflow resistance, and an electronic component device obtained using the same.

Means for solving the above problems include the following embodiments.
<1> A curable resin composition comprising an epoxy resin and a curing agent, the curing agent comprising a phenol novolac resin including a structural unit derived from a phenol compound represented by the following general formula (1):

(In general formula (1), ^R1 represents a hydrogen atom or a methyl group, ^R2 represents an aliphatic hydrocarbon group having 10 to 18 carbon atoms, and n is an integer of 1 or 2.)
<2> The phenol novolak resin contains at least one structural unit derived from a phenol compound represented by the general formula (1) below, selected from the group consisting of structural units derived from a phenol compound represented by the general formula (1-1) to (1-3). The curable resin composition according to <1>.

(In the general formulas (1-1) to (1-3), ^R2 has the same meaning as ^R2 in the general formula (1).)
<3> The curable resin composition according to <1> or <2>, wherein the phenol novolak resin further contains a structural unit derived from a phenol compound other than the phenol compound represented by the general formula (1).
<4> The curable resin composition according to any one of <1> to <3>, wherein the curing agent further contains a curing agent other than a phenol novolac resin containing a structural unit derived from a phenol compound represented by the general formula (1).
<5> The curable resin composition according to any one of <1> to <4>, for use as a sealing material for electronic component devices.
<6> An electronic component device comprising: an element; and a cured product of the curable resin composition according to any one of <1> to <5> that encapsulates the element.

The present invention provides a curable resin composition that can provide a sealing structure that has excellent adhesion to metals and reflow resistance, and an electronic component device obtained using the same.

The following describes in detail the form for carrying out the present invention. However, the present invention is not limited to the following embodiments. In the following embodiments, the components (including element steps, etc.) are not essential unless specifically stated otherwise. The same applies to numerical values and their ranges, and they do not limit the present invention.

In the present disclosure, the term "step" includes not only a step that is independent of other steps, but also a step that cannot be clearly distinguished from other steps as long as the purpose of the step is achieved.
In the present disclosure, the numerical range indicated using "to" includes the numerical values before and after "to" as the minimum and maximum values, respectively.
In the present disclosure, in the ranges of numerical values described stepwise, the upper or lower limit value described in one range of numerical values may be replaced with the upper or lower limit value of another range of numerical values described stepwise. In addition, in the ranges of numerical values described, the upper or lower limit value of the range of numerical values may be replaced with the value shown in the examples.
In the present disclosure, the content or amount of each component in a composition means, when multiple substances corresponding to each component are present in the composition, the total content or amount of the multiple substances present in the composition, unless otherwise specified.
In the present disclosure, the particle size of each component in a composition means the value for a mixture of the multiple types of particles present in the composition, unless otherwise specified, when multiple types of particles corresponding to each component are present in the composition.

<Curable resin composition>
The curable resin composition of the present disclosure includes an epoxy resin and a curing agent, and the curing agent includes a phenol novolac resin (hereinafter also referred to as a specific phenol novolac resin) including a structural unit derived from a phenol compound represented by the following general formula (1):

In the formula, R ¹ represents a hydrogen atom or a methyl group, R ² represents an aliphatic hydrocarbon group having 10 to 18 carbon atoms, and n is an integer of 1 or 2.

The curable resin composition containing the specific phenol novolac resin has excellent adhesion to metals (especially gold) in the cured state. The reason for this is not entirely clear, but it is thought that, for example, the aliphatic hydrocarbon group having 10 to 18 carbon atoms in the structural unit derived from the phenol compound contained in the specific phenol novolac resin acts to improve adhesion to metals. Furthermore, the aliphatic hydrocarbon group having 10 to 18 carbon atoms in the structural unit derived from the phenol compound contained in the specific phenol novolac resin acts to reduce the elastic modulus and water absorption rate near the interface between the metal surface and the cured product of the curable resin composition, which is thought to improve reflow resistance.

The curable resin composition containing the specific phenol novolac resin has excellent adhesion to metals in the cured state, and is therefore suitable as an encapsulant for packages containing lead frames whose surface is at least made of metal (particularly gold). An example of a lead frame whose surface is at least made of gold is a copper lead frame called PPF (Pre Plating Lead Frame) that is plated with Ni-Pd-Au.

(Specific phenol novolac resin)
The specific phenol novolac resin is a phenol novolac resin containing a structural unit derived from a phenol compound represented by the following general formula (1).

In general formula (1), R ¹ represents a hydrogen atom or a methyl group, R ² represents an aliphatic hydrocarbon group having 10 to 18 carbon atoms, and n is an integer of 1 or 2.

The structural units derived from the phenol compound represented by general formula (1) contained in the specific phenol novolac resin may all have the same structure or may be different from each other. When the specific phenol novolac resin contains two or more types of structural units derived from the phenol compound represented by general formula (1), the arrangement of these units is not particularly limited and may be arranged regularly or irregularly.

In one embodiment, the specific phenol novolak resin may contain at least a structural unit (monohydric phenol) where n is 1 and a structural unit (dihydric phenol) where n is 2 as structural units derived from a phenol compound represented by general formula (1), or may contain at least a structural unit (monohydric phenol) where n is 1 and a structural unit where n is 2 in which one hydroxyl group is in the meta position relative to the other hydroxyl group.

The specific phenol novolac resin may contain at least one of the structural units derived from the phenol compound represented by the following general formulas (1-1) to (1-3) as a structural unit derived from the phenol compound represented by the general formula (1), or may contain all of the structural units derived from the phenol compound represented by the general formulas (1-1) to (1-3).

In the general formulae (1-1) to (1-3), R ² has the same meaning as R ² in the general formula (1).

In the general formula (1), the aliphatic hydrocarbon group having 10 to 18 carbon atoms represented by R ² may be an aliphatic hydrocarbon group having 13 to 16 carbon atoms, and may or may not have an unsaturated double bond. When the aliphatic hydrocarbon group having 10 to 18 carbon atoms represented by R ² has an unsaturated double bond, the number of unsaturated double bonds is not particularly limited, and may be, for example, 1 to 5. The aliphatic hydrocarbon group having 10 to 18 carbon atoms represented by R ² may be branched or unbranched, but is preferably unbranched. Specific examples of the aliphatic hydrocarbon group having 10 to 18 carbon atoms represented by R ² include aliphatic hydrocarbon groups represented by the following group (A) (* indicates the bonding position with the aromatic ring). The structures of the aliphatic hydrocarbon groups having 10 to 18 carbon atoms represented by R ² in the specific phenol novolac resin may be the same or different.

The specific phenol novolac resin may further contain structural units derived from a phenol compound other than the phenol compound represented by general formula (1). Examples of the phenol compound other than the phenol compound represented by general formula (1) include the phenol compound represented by the following general formula (2).

In the general formula (2), ^R1 represents a hydrogen atom or a methyl group, and n is an integer of 1 or 2. Examples of the phenol compound represented by the general formula (2) include monohydric phenol compounds such as phenol and cresol, and dihydric phenol compounds such as resorcin, catechol, and hydroquinone.

In one embodiment, the specific phenol novolak resin may contain either or both of phenol and cresol as structural units derived from the phenol compound represented by general formula (2), or may contain either or both of phenol and orthocresol.

When the specific phenol novolac resin contains structural units derived from a phenol compound other than the phenol compound represented by general formula (1), the proportion of the structural units derived from the phenol compound represented by general formula (1) in the entire specific phenol novolac resin is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more.

The method for synthesizing the specific phenol novolac resin is not particularly limited. For example, the specific phenol novolac resin can be synthesized by reacting a phenol compound, which is the raw material for the specific phenol novolac resin, with an aldehyde such as formaldehyde in the presence of an acid catalyst.

The molecular weight of the specific phenol novolac resin is not particularly limited. For example, the weight average molecular weight measured by gel permeation chromatography may be in the range of 300 to 20,000.

The viscosity of the specific phenol novolac resin is not particularly limited. For example, the viscosity at 25°C is preferably 50 Pa·s or less, and more preferably 30 Pa·s or less. The viscosity of the specific phenol novolac resin at 25°C is the value (Pa·s) obtained by multiplying the measured value when an EHD type rotational viscometer equipped with a cone rotor with a cone angle of 3° and a cone radius of 14 mm is rotated at 10 revolutions per minute (10 rpm) at 25°C for 1 minute by a predetermined conversion coefficient (0.5).

The hydroxyl group equivalent of the specific phenol novolac resin is not particularly limited. From the viewpoint of the balance of various properties such as moldability, reflow resistance, and electrical reliability, it is preferably 70 g/eq to 1000 g/eq, and more preferably 80 g/eq to 500 g/eq.

It is preferable to use the specific phenol novolac resin in combination with a curing agent other than the specific phenol novolac resin. In other words, it is preferable that the curable resin composition contains the specific phenol novolac resin as a curing agent and a curing agent other than the specific phenol novolac resin.

When the curable resin composition contains a specific phenol novolac resin as a curing agent and a curing agent other than the specific phenol novolac resin, from the viewpoint of curability, the proportion of the specific phenol novolac resin in the entire curing agent is preferably 50% or less on an equivalent basis, more preferably 30% or less, and even more preferably 20% or less. From the viewpoint of improving adhesion to metal, the proportion of the specific phenol novolac resin in the entire curing agent is preferably 1% or more on an equivalent basis, more preferably 3% or more, and even more preferably 5% or more.

The type of curing agent other than the specific phenol novolac resin is not particularly limited and can be selected according to the desired properties of the curable resin composition. Specific examples of curing agents will be described later.

(Epoxy resin)
The type of epoxy resin contained in the curable resin composition is not particularly limited, and can be selected according to the desired properties of the curable resin composition. Specific examples of the epoxy resin include novolac-type epoxy resins (phenol novolac-type epoxy resins, orthocresol novolac-type epoxy resins, etc.) obtained by epoxidizing a novolac resin obtained by condensing or co-condensing at least one phenolic compound selected from the group consisting of phenolic compounds such as phenol, cresol, xylenol, resorcin, catechol, bisphenol A, bisphenol F, etc., and naphthol compounds such as α-naphthol, β-naphthol, dihydroxynaphthalene, etc., with an aliphatic aldehyde compound such as formaldehyde, acetaldehyde, propionaldehyde, etc., under an acidic catalyst; triphenylmethane-type phenolic resins (triphenylmethane-type phenolic resins, etc.) obtained by epoxidizing a triphenylmethane-type phenolic resin obtained by condensing or co-condensing the above-mentioned phenolic compound with an aromatic aldehyde compound such as benzaldehyde, salicylaldehyde, etc., under an acidic catalyst; diphenylmethane-type epoxy resins; copolymer epoxy resins obtained by epoxidizing novolak resins obtained by co-condensing the above-mentioned phenol compounds and naphthol compounds with aldehyde compounds under an acidic catalyst; diphenylmethane-type epoxy resins which are diglycidyl ethers of bisphenol A, bisphenol F, etc.; biphenyl-type epoxy resins which are diglycidyl ethers of alkyl-substituted or unsubstituted biphenols; stilbene-type epoxy resins which are diglycidyl ethers of stilbene-based phenol compounds; sulfur-containing epoxy resins which are diglycidyl ethers of bisphenol S, etc.; epoxy resins which are glycidyl ethers of alcohols such as butanediol, polyethylene glycol, and polypropylene glycol; glycidyl ester-type epoxy resins which are glycidyl esters of polyvalent carboxylic acid compounds such as phthalic acid, isophthalic acid, and tetrahydrophthalic acid. glycidylamine-type epoxy resins in which active hydrogen attached to nitrogen atoms of aniline, diaminodiphenylmethane, isocyanuric acid, etc. is replaced with a glycidyl group; dicyclopentadiene-type epoxy resins in which a co-condensed resin of dicyclopentadiene and a phenol compound is epoxidized; alicyclic epoxy resins such as vinylcyclohexene diepoxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and 2-(3,4-epoxy)cyclohexyl-5,5-spiro(3,4-epoxy)cyclohexane-m-dioxane in which an olefin bond in a molecule is epoxidized; paraxylylene-modified epoxy resins which are glycidyl ethers of paraxylylene-modified phenolic resins; metaxylylene-modified epoxy resins which are glycidyl ethers of metaxylylene-modified phenolic resins; terpene-modified phenolic resins Terpene-modified epoxy resins are glycidyl ethers of phenol resins; dicyclopentadiene-modified epoxy resins are glycidyl ethers of dicyclopentadiene-modified phenol resins; cyclopentadiene-modified epoxy resins are glycidyl ethers of cyclopentadiene-modified phenol resins; polycyclic aromatic ring-modified epoxy resins are glycidyl ethers of polycyclic aromatic ring-modified phenol resins; naphthalene-type epoxy resins are glycidyl ethers of naphthalene ring-containing phenol resins; halogenated phenol novolac-type epoxy resins; hydroquinone-type epoxy resins; trimethylolpropane-type epoxy resins; linear aliphatic epoxy resins obtained by oxidizing olefin bonds with peracids such as peracetic acid; aralkyl-type epoxy resins obtained by epoxidizing aralkyl-type phenol resins such as phenol aralkyl resins and naphthol aralkyl resins; and the like. Furthermore, epoxy-oxidized products of silicone resins and epoxy-oxidized products of acrylic resins can also be mentioned as epoxy resins. These epoxy resins may be used alone or in combination of two or more.

Among the above epoxy resins, from the viewpoint of the balance between reflow resistance and fluidity, epoxy resins selected from the group consisting of biphenyl type epoxy resins, stilbene type epoxy resins, diphenylmethane type epoxy resins, sulfur atom-containing type epoxy resins, novolac type epoxy resins, dicyclopentadiene type epoxy resins, triphenylmethane type epoxy resins, copolymer type epoxy resins, and aralkyl type epoxy resins (these are referred to as "specific epoxy resins"). The specific epoxy resins may be used alone or in combination of two or more.

When the epoxy resin contains a specific epoxy resin, from the viewpoint of exerting the performance of the specific epoxy resin, the content is preferably 30% by mass or more of the total epoxy resin, and more preferably 50% by mass or more.

Among the specific epoxy resins, biphenyl-type epoxy resins, stilbene-type epoxy resins, diphenylmethane-type epoxy resins, and sulfur-atom-containing epoxy resins are more preferable from the viewpoint of fluidity, and dicyclopentadiene-type epoxy resins, triphenylmethane-type epoxy resins, and aralkyl-type epoxy resins are preferable from the viewpoint of heat resistance. Specific examples of preferable epoxy resins are shown below.

The biphenyl type epoxy resin is not particularly limited as long as it is an epoxy resin having a biphenyl skeleton. For example, an epoxy resin represented by the following general formula (II) is preferred. Among the epoxy resins represented by the following general formula (II), commercially available products include YX-4000H (trade name, Mitsubishi Chemical Corporation) in which the 3,3',5,5' positions of R ⁸ are methyl groups when the oxygen atoms are substituted at the 4 and 4' positions, and the other R ⁸ are hydrogen atoms, 4,4'-bis(2,3-epoxypropoxy)biphenyl in which all R ⁸ are hydrogen atoms, and YL-6121H (trade name, Mitsubishi Chemical Corporation) which is a mixture of the cases where all R ⁸ are hydrogen atoms and the cases where the 3,3',5,5' positions of R ⁸ are methyl groups when the oxygen atoms are substituted at the 4 and 4' positions, and the other R ⁸ are hydrogen atoms.

In formula (II), R ⁸ represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or an aromatic group having 4 to 18 carbon atoms, and may be the same or different from each other. n represents an average value and is a number from 0 to 10.

The stilbene type epoxy resin is not particularly limited as long as it is an epoxy resin having a stilbene skeleton. For example, an epoxy resin represented by the following general formula (III) is preferred. Among the epoxy resins represented by the following general formula (III), ESLV-210 (trade name, Sumitomo Chemical Co., Ltd.), which is a mixture of a case in which the 3,3',5,5' positions of R ⁹ are methyl groups, the remaining R ⁹ are hydrogen atoms, and all R ¹⁰ are hydrogen atoms, when the positions of R ⁹ substituted with oxygen atoms are the 4 and 4' positions, and a case in which three of the 3,3',5,5' positions of R 9 are methyl groups, one is a t-butyl group, the remaining R ⁹ are hydrogen atoms, and all R ¹⁰ are hydrogen atoms, is commercially available.

In formula (III), R ⁹ and R ¹⁰ each represent a hydrogen atom or a monovalent organic group having 1 to 18 carbon atoms, and may be the same or different from each other. n represents an average value and is a number from 0 to 10.

The diphenylmethane type epoxy resin is not particularly limited as long as it is an epoxy resin having a diphenylmethane skeleton. For example, an epoxy resin represented by the following general formula (IV) is preferred. Among the epoxy resins represented by the following general formula (IV), YSLV-80XY (Nippon Steel Sumikin Chemical Co., Ltd., trade name) and the like in which all of R ¹¹ are hydrogen atoms, 3,3',5,5' positions of R ¹² are methyl groups when the positions at which oxygen atoms are substituted are the 4 and 4' positions, and the other R ¹² are hydrogen atoms, are commercially available.

In formula (IV), R ¹¹ and R ¹² each represent a hydrogen atom or a monovalent organic group having 1 to 18 carbon atoms, and may be the same or different from each other. n represents an average value and is a number from 0 to 10.

The sulfur-containing epoxy resin is not particularly limited as long as it is an epoxy resin containing a sulfur atom. For example, an epoxy resin represented by the following general formula (V) can be mentioned. Among the epoxy resins represented by the following general formula (V), YSLV-120TE (Nippon Steel Sumikin Chemical Co., Ltd., trade name) in which the 3,3' positions are t-butyl groups, the 6,6' positions are methyl groups, and the remaining R ¹³ are hydrogen atoms, when the oxygen atom substitution positions of R ¹³ are the 4 and 4' positions, is commercially available.

In formula (V), R ¹³ represents a hydrogen atom or a monovalent organic group having 1 to 18 carbon atoms, and may be the same or different from each other. n represents an average value and is a number from 0 to 10.

The novolac epoxy resin is not particularly limited as long as it is an epoxy resin obtained by epoxidizing a novolac phenolic resin. For example, an epoxy resin obtained by epoxidizing a novolac phenolic resin such as a phenol novolac resin, a cresol novolac resin, or a naphthol novolac resin using a method such as glycidyl etherification is preferred, and an epoxy resin represented by the following general formula (VI) is more preferred. Among the epoxy resins represented by the following general formula (VI), there are ESCN-190 and ESCN-195 (trade names, Sumitomo Chemical Co., Ltd.) in which all of R ¹⁴ are hydrogen atoms, R ¹⁵ are methyl groups, and i=1, N-770 and N-775 (trade names, DIC Corporation) in which all of R ¹⁴ are hydrogen atoms and i=0, YDAN-1000-10C (trade name, Nippon Steel & Sumikin Chemical Co., Ltd.) which is a styrene-modified phenol novolac type epoxy resin having a portion where all of R ¹⁴ are hydrogen atoms, i=0 and a portion where i=1 and R ¹⁵ is -CH(CH ₃ )-Ph, and YDAN-1000-10C (trade name, Nippon Steel & Sumikin Chemical Co., Ltd.) which is a styrene-modified phenol novolac type epoxy resin having a portion where all of R ¹⁴ are hydrogen atoms, i=1, R ¹⁵ is a methyl group, and a portion where i=2 and R HP-5600 (trade name, DIC Corporation), which is a benzyl-modified cresol novolac epoxy resin having ¹⁵ moieties, one of which is a methyl group and the other of which is a benzyl group, is commercially available.

In formula (VI), R ¹⁴ represents a hydrogen atom or a monovalent organic group having 1 to 18 carbon atoms, and may be the same or different. R ¹⁵ represents a monovalent organic group having 1 to 18 carbon atoms, and may be the same or different. Each i independently represents an integer of 0 to 3. n is an average value and represents a number of 0 to 10.

The dicyclopentadiene type epoxy resin is not particularly limited as long as it is an epoxy resin obtained by epoxidizing a compound having a dicyclopentadiene skeleton as a raw material. For example, an epoxy resin represented by the following general formula (VII) is preferred. Among the epoxy resins represented by the following general formula (VII), HP-7200 (DIC Corporation, trade name) where i=0 is available as a commercially available product.

In formula (VII), R ¹⁶ represents a monovalent organic group having 1 to 18 carbon atoms, and may be the same or different from each other. Each i independently represents an integer of 0 to 3. n is an average value and represents a number of 0 to 10.

The triphenylmethane type epoxy resin is not particularly limited as long as it is an epoxy resin made from a compound having a triphenylmethane skeleton. For example, an epoxy resin obtained by glycidyl etherifying a triphenylmethane type phenolic resin such as a novolac type phenolic resin made of a compound having a triphenylmethane skeleton and a compound having a phenolic hydroxyl group is preferred, and an epoxy resin represented by the following general formula (VIII) is more preferred. Among the epoxy resins represented by the following general formula (VIII), 1032H60 (product name, Mitsubishi Chemical Corporation) and EPPN-502H (product name, Nippon Kayaku Co., Ltd.), in which i is 0 and k is 0, are commercially available.

In formula (VIII), R ¹⁷ and R ¹⁸ each represent a monovalent organic group having 1 to 18 carbon atoms and may be the same or different. Each i independently represents an integer of 0 to 3, and each k independently represents an integer of 0 to 4. n is an average value and represents a number of 0 to 10.

The copolymerized epoxy resin obtained by epoxidizing a novolac resin obtained from a naphthol compound, a phenol compound, and an aldehyde compound is not particularly limited as long as it is an epoxy resin made from a compound having a naphthol skeleton and a compound having a phenol skeleton as raw materials. For example, an epoxy resin obtained by glycidyl etherification of a novolac phenol resin using a compound having a naphthol skeleton and a compound having a phenol skeleton is preferred, and an epoxy resin represented by the following general formula (IX) is more preferred. Among the epoxy resins represented by the following general formula (IX), NC-7300 (Nippon Kayaku Co., Ltd., trade name) in which R ²¹ is a methyl group, i is 1, j is 0, and k is 0 is commercially available.

In formula (IX), R ¹⁹ to R ²¹ represent a monovalent organic group having 1 to 18 carbon atoms, and may be the same or different. Each i is independently an integer of 0 to 3, each j is independently an integer of 0 to 2, and each k is independently an integer of 0 to 4. Each l and m is an average value, a number of 0 to 10, and (l+m) represents a number of 0 to 10. The terminal of the epoxy resin represented by formula (IX) is either one of the following formulas (IX-1) or (IX-2). In formulas (IX-1) and (IX-2), the definitions of i, j, and k for R ¹⁹ to R ²¹ are the same as those for i, j, and k for R ¹⁹ to R ²¹ in formula (IX). n is 1 (when bonded via a methylene group) or 0 (when not bonded via a methylene group).

The epoxy resin represented by the above general formula (IX) may be a random copolymer containing l structural units and m structural units arranged randomly, an alternating copolymer containing them alternately, a copolymer containing them regularly, or a block copolymer containing them in a block form. Any one of these may be used alone, or two or more may be used in combination.

As a copolymerized epoxy resin, Epicron HP-5000 (trade name, DIC Corporation), which is a methoxynaphthalene-cresol formaldehyde co-condensed epoxy resin containing the following two structural units in a random, alternating or block order, and is represented by the following general formula: In the following general formula, n and m are each an average value and a number from 0 to 10, and (n+m) is a number from 0 to 10, preferably n and m are each an average value and a number from 1 to 9, and (n+m) is a number from 2 to 10.

The aralkyl type epoxy resin is not particularly limited as long as it is an epoxy resin made from at least one selected from the group consisting of phenolic compounds such as phenol and cresol, and naphthol compounds such as naphthol and dimethylnaphthol, and a phenolic resin synthesized from dimethoxyparaxylene, bis(methoxymethyl)biphenyl, or a derivative thereof. For example, an epoxy resin obtained by glycidyl etherifying a phenolic resin synthesized from at least one selected from the group consisting of phenolic compounds such as phenol and cresol, and naphthol compounds such as naphthol and dimethylnaphthol, and dimethoxyparaxylene, bis(methoxymethyl)biphenyl, or a derivative thereof is preferred, and epoxy resins represented by the following general formulas (X) and (XI) are more preferred.

Among the epoxy resins represented by the following general formula (X), NC-3000S (trade name, Nippon Kayaku Co., Ltd.) in which i is 0 and R ³⁸ is a hydrogen atom, and CER-3000 (trade name, Nippon Kayaku Co., Ltd.) in which an epoxy resin in which i is 0 and R ³⁸ is a hydrogen atom and an epoxy resin in which all R ⁸ in general formula (II) are hydrogen atoms are mixed in a mass ratio of 80:20 are commercially available. Furthermore, among the epoxy resins represented by the following general formula (XI), ESN-175 (trade name, Nippon Steel & Sumikin Chemical Co., Ltd.) in which i is 0, j is 0, and k is 0 are commercially available.

In formulae (X) and (XI), R ³⁸ represents a hydrogen atom or a monovalent organic group having 1 to 18 carbon atoms, and may be the same or different. R ³⁷ , R ³⁹ to R ⁴¹ represent a monovalent organic group having 1 to 18 carbon atoms, and may be the same or different. Each i is independently an integer of 0 to 3, each j is independently an integer of 0 to 2, each k is independently an integer of 0 to 4, and each 1 is independently an integer of 0 to 6. Each n is an average value, and is independently a number of 0 to 10.

With respect to R ⁸ to R ²¹ and R ³⁷ to R ⁴¹ in the above general formulas (II) to (XI), "each may be the same or different" means, for example, that all 8 to 88 R ^8s in formula (II) may be the same or different. The other R ⁹ to R ²¹ and R ³⁷ to R ⁴¹ also mean that the respective numbers contained in the formula may all be the same or different. In addition, R ⁸ to R ²¹ and R ³⁷ to R ⁴¹ may each be the same or different. For example, all R ^9s and R ^10s may be the same or different.
In addition, the organic group having 1 to 18 carbon atoms in the general formulae (III) to (XI) is preferably an alkyl group or an aryl group.

In the above general formulas (II) to (XI), n is an average value, and each is preferably independently in the range of 0 to 10. If n is 10 or less, the melt viscosity of the resin component does not become too high, and the viscosity of the curable resin composition during melt molding decreases, and the occurrence of filling defects, deformation of the bonding wire (gold wire connecting the element and the lead), etc. tends to be suppressed. It is more preferable that n is set in the range of 0 to 4.

The epoxy equivalent of the epoxy resin is not particularly limited. From the viewpoint of the balance of various properties such as moldability, reflow resistance, and electrical reliability, the epoxy equivalent of the epoxy resin is preferably 100 g/eq to 1000 g/eq, and more preferably 150 g/eq to 500 g/eq.

The softening point or melting point of the epoxy resin is not particularly limited. From the viewpoints of moldability and reflow resistance, it is preferably 40°C to 180°C, and from the viewpoint of handleability when preparing the curable resin composition, it is more preferably 50°C to 130°C.

From the viewpoints of strength, fluidity, heat resistance, moldability, etc., the content of the epoxy resin in the curable resin composition is preferably 0.5% by mass to 50% by mass, and more preferably 2% by mass to 30% by mass.

(Hardening agents other than specific phenol novolac resins)
The type of curing agent other than the specific phenol novolac resin contained in the curable resin composition is not particularly limited, and can be selected according to the type of epoxy resin used in combination, the desired properties of the curable resin composition, etc. Examples of the curing agent used in combination with the epoxy resin include a phenol curing agent, an amine curing agent, an acid anhydride curing agent, a polymercaptan curing agent, a polyaminoamide curing agent, an isocyanate curing agent, and a blocked isocyanate curing agent. From the viewpoint of achieving both curability and pot life, at least one selected from the group consisting of a phenol curing agent, an amine curing agent, and an acid anhydride curing agent is preferred, and from the viewpoint of electrical reliability, a phenol curing agent is more preferred.

Examples of phenolic hardeners include phenolic resins and polyhydric phenolic compounds having two or more phenolic hydroxyl groups in one molecule. Specifically, polyhydric phenolic compounds such as resorcin, catechol, bisphenol A, bisphenol F, substituted or unsubstituted biphenols, etc.; novolac-type phenolic resins obtained by condensing or co-condensing at least one phenolic compound selected from the group consisting of phenolic compounds such as phenol, cresol, xylenol, resorcin, catechol, bisphenol A, bisphenol F, phenylphenol, aminophenol, etc., and naphthol compounds such as α-naphthol, β-naphthol, dihydroxynaphthalene, etc., with aldehyde compounds such as formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, salicylaldehyde, etc., under an acid catalyst; and polyhydric phenolic compounds such as dimethoxyparaxylene, bis(methoxymethyl)biphenyl, etc. Aralkyl-type phenolic resins such as phenol aralkyl resins and naphthol aralkyl resins synthesized from the above; paraxylylene and/or metaxylylene modified phenolic resins; melamine modified phenolic resins; terpene modified phenolic resins; dicyclopentadiene type phenolic resins and dicyclopentadiene type naphthol resins synthesized by copolymerization of the above phenolic compounds and dicyclopentadiene; cyclopentadiene modified phenolic resins; polycyclic aromatic ring modified phenolic resins; biphenyl type phenolic resins; triphenylmethane type phenolic resins obtained by condensing or co-condensing the above phenolic compounds with aromatic aldehyde compounds such as benzaldehyde and salicylaldehyde under an acid catalyst; and phenolic resins obtained by copolymerizing two or more of these. These phenolic curing agents may be used alone or in combination of two or more.

Among the phenolic hardeners, from the viewpoint of reflow resistance, at least one selected from the group consisting of aralkyl-type phenolic resins, dicyclopentadiene-type phenolic resins, triphenylmethane-type phenolic resins, copolymerized phenolic resins of benzaldehyde-type phenolic resins and aralkyl-type phenolic resins, and novolac-type phenolic resins (these are referred to as "specific phenolic hardeners"). The specific phenolic hardeners may be used alone or in combination of two or more.

When the curing agent contains a specific phenol curing agent, in order to fully exert its performance, the content of the specific phenol curing agent is preferably 30% by mass or more of the total curing agent, and more preferably 50% by mass or more.

Examples of aralkyl-type phenolic resins include phenol aralkyl resins and naphthol aralkyl resins synthesized from phenolic compounds and dimethoxy-para-xylene, bis(methoxymethyl)biphenyl, etc. The aralkyl-type phenolic resins may be further copolymerized with other phenolic resins. Examples of copolymerized aralkyl-type phenolic resins include copolymerized phenolic resins of benzaldehyde-type phenolic resins and aralkyl-type phenolic resins, copolymerized phenolic resins of salicylaldehyde-type phenolic resins and aralkyl-type phenolic resins, and copolymerized phenolic resins of novolac-type phenolic resins and aralkyl-type phenolic resins.

The aralkyl phenolic resin is not particularly limited as long as it is a phenolic resin synthesized from at least one selected from the group consisting of phenolic compounds and naphthol compounds, and dimethoxy-para-xylene, bis(methoxymethyl)biphenyl, or a derivative thereof. For example, phenolic resins represented by the following general formulas (XII) to (XIV) are preferred.

In formulas (XII) to (XIV), R ²³ represents a hydrogen atom or a monovalent organic group having 1 to 18 carbon atoms, and may be the same or different. ^{R 22} , R ²⁴ , R ²⁵ and R ²⁸ represent a monovalent organic group having 1 to 18 carbon atoms, and may be the same or different. R ²⁶ and R ²⁷ represent a hydroxyl group or a monovalent organic group having 1 to 18 carbon atoms, and may be the same or different. Each i is independently an integer of 0 to 3, each j is independently an integer of 0 to 2, each k is independently an integer of 0 to 4, and each p is independently an integer of 0 to 4. Each n is an average value, and is independently a number of 0 to 10.

Among the phenolic resins represented by the above general formula (XII), MEH-7851 (trade name, Meiwa Kasei Co., Ltd.), in which i is 0 and all of R ²³ are hydrogen atoms, is commercially available.

Among the phenolic resins represented by the above general formula (XIII), XL-225, XLC (Mitsui Chemicals, Inc., product name), MEH-7800 (Meiwa Chemical Industry Co., Ltd., product name), etc., in which i is 0 and k is 0, are commercially available.

Among the phenolic resins represented by the general formula (XIV), SN-170 (product name, Nippon Steel & Sumikin Chemical Co., Ltd.), in which j is 0, k is 0, and p is 0, and SN-395 (product name, Nippon Steel & Sumikin Chemical Co., Ltd.), in which j is 0, k is 1, R ²⁷ is a hydroxyl group, and p is 0, are commercially available.

The dicyclopentadiene-type phenolic resin is not particularly limited as long as it is a phenolic resin obtained from a compound having a dicyclopentadiene skeleton as a raw material. For example, a phenolic resin represented by the following general formula (XV) is preferred. Among the phenolic resins represented by the following general formula (XV), DPP (trade name, Nippon Petrochemical Co., Ltd.), in which i is 0, is commercially available.

In formula (XV), R ²⁹ represents a monovalent organic group having 1 to 18 carbon atoms, and may be the same or different from each other. Each i independently represents an integer of 0 to 3. n is an average value and represents a number of 0 to 10.

The triphenylmethane type phenolic resin is not particularly limited as long as it is a phenolic resin obtained from a compound having a triphenylmethane skeleton as a raw material. For example, a phenolic resin represented by the following general formula (XVI) is preferred.

Among the phenolic resins represented by the following general formula (XVI), MEH-7500 (product name, Meiwa Kasei Co., Ltd.), in which i is 0 and k is 0, is commercially available.

In formula (XVI), R ³⁰ and R ³¹ each represent a monovalent organic group having 1 to 18 carbon atoms and may be the same or different. Each i is independently an integer of 0 to 3, and each k is independently an integer of 0 to 4. n is an average value and is a number of 0 to 10.

The copolymerized phenolic resin of a benzaldehyde type phenolic resin and an aralkyl type phenolic resin is not particularly limited as long as it is a copolymerized phenolic resin of a phenolic resin obtained from a compound having a benzaldehyde skeleton and an aralkyl type phenolic resin. For example, a phenolic resin represented by the following general formula (XVII) is preferred.

Among the phenolic resins represented by the following general formula (XVII), HE-510 (trade name, Air Water Chemical Inc.), in which i is 0, k is 0, and q is 0, is commercially available.

In formula (XVII), R ³² to R ³⁴ represent a monovalent organic group having 1 to 18 carbon atoms, and may be the same or different. Each i is independently an integer of 0 to 3, each k is independently an integer of 0 to 4, and each q is independently an integer of 0 to 5. Each l and m is an average value, and each is independently a number of 0 to 11. However, the sum of l and m is a number of 1 to 11.

The novolac-type phenolic resin is not particularly limited as long as it is a phenolic resin obtained by condensing or co-condensing at least one phenolic compound selected from the group consisting of phenol compounds and naphthol compounds with an aldehyde compound under an acid catalyst. For example, a phenolic resin represented by the following general formula (XVIII) is preferred.

Among the phenol resins represented by the following general formula (XVIII), Tamanol 758 and 759 ⁽ trade names, Arakawa Chemical Industries, Ltd.) and HP-850N (trade name, Hitachi Chemical Co., Ltd.), in which i is 0 and all of R 35 are hydrogen atoms, are commercially available.

In formula (XVIII), R ³⁵ represents a hydrogen atom or a monovalent organic group having 1 to 18 carbon atoms, and may be the same or different. R ³⁶ represents a monovalent organic group having 1 to 18 carbon atoms, and may be the same or different. Each i independently represents an integer of 0 to 3. n is an average value and represents a number of 0 to 10.

The phrase "all of R ²² to R ³⁶ may be the same or different" in the above general formulas (XII) to (XVIII) means that, for example, all of the i R ^22s in formula (XII) may be the same or different from each other. The other R ²³ to R ³⁶ in the formula may also be the same or different from each other in terms of the number of each of them. In addition, R ²² to R ³⁶ may be the same or different from each other. For example, R ²² and R ²³ may be the same or different from each other, and R ³⁰ and R ³¹ may be the same or different from each other.

In the above general formulas (XII) to (XVIII), n is preferably in the range of 0 to 10. If it is 10 or less, the melt viscosity of the resin component will not be too high, and the viscosity of the curable resin composition during melt molding will also be low, making it less likely that unfilled defects or deformation of the bonding wire (gold wire connecting the element and the lead) will occur. The average n in one molecule is preferably set in the range of 0 to 4.

The functional group equivalent of the curing agent (hydroxyl group equivalent in the case of a phenolic curing agent) is not particularly limited. From the viewpoint of the balance of various properties such as moldability, reflow resistance, and electrical reliability, it is preferably 70 g/eq to 1000 g/eq, and more preferably 80 g/eq to 500 g/eq.

The softening point or melting point of the curing agent is not particularly limited. From the viewpoint of moldability and reflow resistance, it is preferably 40°C to 180°C, and from the viewpoint of handleability during the production of the curable resin composition, it is more preferably 50°C to 130°C.

The equivalent ratio of epoxy resin to curing agent, i.e., the ratio of the number of functional groups in the curing agent to the number of functional groups in the epoxy resin (number of functional groups in the curing agent/number of functional groups in the epoxy resin), is not particularly limited. In terms of keeping the amount of unreacted components low, it is preferably set in the range of 0.5 to 2.0, and more preferably in the range of 0.6 to 1.3. From the standpoint of moldability and reflow resistance, it is even more preferable to set it in the range of 0.8 to 1.2.

(Cure Accelerator)
The curable resin composition may contain a curing accelerator. The type of the curing accelerator is not particularly limited and can be selected depending on the type of the curable resin, the desired properties of the curable resin composition, and the like.

From the viewpoint of curability and fluidity, it is preferable that the curing accelerator contains a phosphonium compound. Specific examples of phosphonium compounds include triphenylphosphine, diphenyl(p-tolyl)phosphine, tris(alkylphenyl)phosphine, tris(alkoxyphenyl)phosphine, tris(alkyl-alkoxyphenyl)phosphine, tris(dialkylphenyl)phosphine, tris(trialkylphenyl)phosphine, tris(tetraalkylphenyl)phosphine, tris(dialkoxyphenyl)phosphine, tris(trialkoxyphenyl)phosphine, tris(tetraalkoxyphenyl)phosphine, trialkoxyphenyl ... compounds having intramolecular polarization obtained by adding a tertiary phosphine such as arylphosphine, dialkylarylphosphine, or alkyldiarylphosphine to a compound having a π bond, such as maleic anhydride, 1,4-benzoquinone, 2,5-toluquinone, 1,4-naphthoquinone, 2,3-dimethylbenzoquinone, 2,6-dimethylbenzoquinone, 2,3-dimethoxy-5-methyl-1,4-benzoquinone, 2,3-dimethoxy-1,4-benzoquinone, or phenyl-1,4-benzoquinone, or a compound having a π bond, such as diazophenylmethane; Finn compounds and 4-bromophenol, 3-bromophenol, 2-bromophenol, 4-chlorophenol, 3-chlorophenol, 2-chlorophenol, 4-iodophenol, 3-iodophenol, 2-iodophenol, 4-bromo-2-methylphenol, 4-bromo-3-methylphenol, 4-bromo-2,6-dimethylphenol, 4-bromo-3,5-dimethylphenol, 4-bromo-2,6-di-tert-butylphenol, 4-chloro-1-naphthol, 1-bromo-2-naphthol, 6-bromo-2-naphthol , 4-bromo-4'-hydroxybiphenyl and other halogenated phenol compounds are reacted and then subjected to a dehydrohalogenation process, and these compounds have intramolecular polarization; tetra-substituted phosphonium compounds such as tetraphenylphosphonium, tetra-substituted phosphonium compounds and tetra-substituted borates that do not have a phenyl group bonded to a boron atom, such as tetra-p-tolylborate; salts of tetra-substituted phosphonium compounds and anions resulting from the removal of protons from phenol compounds, and salts of tetra-substituted phosphonium compounds and anions resulting from the removal of protons from carboxylic acid compounds.

Among the above phosphonium compounds, the compound represented by the following general formula (I-1) (hereinafter also referred to as the specific curing accelerator) is preferred.

In formula (I-1), R ¹ to R ³ each independently represent a hydrocarbon group having 1 to 18 carbon atoms, and two or more of R ¹ to R ³ may be bonded to each other to form a cyclic structure, and R ⁴ to R ⁷ each independently represent a hydrogen atom, a hydroxyl group, or an organic group having 1 to 18 carbon atoms, and two or more of R ⁴ to R ⁷ may be bonded to each other to form a cyclic structure.

The "hydrocarbon group having 1 to 18 carbon atoms" described as R ¹ to R ³ in general formula (I-1) includes an aliphatic hydrocarbon group having 1 to 18 carbon atoms and an aromatic hydrocarbon group having 6 to 18 carbon atoms.

From the viewpoint of fluidity, the aliphatic hydrocarbon group having 1 to 18 carbon atoms preferably has 1 to 8 carbon atoms, more preferably 2 to 6 carbon atoms, and even more preferably 4 to 6 carbon atoms.

The aliphatic hydrocarbon group having 1 to 18 carbon atoms may be a linear or branched aliphatic hydrocarbon group having 1 to 18 carbon atoms, or an alicyclic hydrocarbon group having 3 to 18 carbon atoms. From the viewpoint of ease of production, a linear or branched aliphatic hydrocarbon group is preferable.

Specific examples of linear or branched aliphatic hydrocarbon groups having 1 to 18 carbon atoms include alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, t-butyl, pentyl, hexyl, octyl, decyl, and dodecyl, allyl, and vinyl groups. The linear or branched aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include alkoxy groups such as methoxy, ethoxy, butoxy, and t-butoxy, aryl groups such as phenyl and naphthyl, hydroxyl, amino, and halogen atoms. The linear or branched aliphatic hydrocarbon group may have two or more substituents, and in that case, the substituents may be the same or different. When the linear or branched aliphatic hydrocarbon group has a substituent, it is preferable that the total number of carbon atoms contained in the aliphatic hydrocarbon group and the substituent is 1 to 18. From the viewpoint of curability, unsubstituted alkyl groups are preferred, unsubstituted alkyl groups having 1 to 8 carbon atoms are more preferred, and n-butyl groups, isobutyl groups, n-pentyl groups, n-hexyl groups, and n-octyl groups are even more preferred.

Specific examples of alicyclic hydrocarbons having 3 to 18 carbon atoms include cycloalkyl groups such as cyclopentyl, cyclohexyl, and cycloheptyl, and cycloalkenyl groups such as cyclopentenyl and cyclohexenyl. The alicyclic hydrocarbon group may or may not have a substituent. Examples of the substituent include alkyl groups such as methyl, ethyl, butyl, and tert-butyl, alkoxy groups such as methoxy, ethoxy, butoxy, and t-butoxy, aryl groups such as phenyl and naphthyl, hydroxyl groups, amino groups, and halogen atoms. The alicyclic hydrocarbon group may have two or more substituents, and in that case, the substituents may be the same or different. When the alicyclic hydrocarbon group has a substituent, it is preferable that the total number of carbon atoms contained in the alicyclic hydrocarbon group and the substituent is 3 to 18. When the alicyclic hydrocarbon group has a substituent, the position of the substituent is not particularly limited. From the viewpoint of curability, unsubstituted cycloalkyl groups are preferred, unsubstituted cycloalkyl groups having 4 to 10 carbon atoms are more preferred, and cyclohexyl groups, cyclopentyl groups, and cycloheptyl groups are even more preferred.

The aromatic hydrocarbon group having 6 to 18 carbon atoms preferably has 6 to 14 carbon atoms, more preferably 6 to 10 carbon atoms. The aromatic hydrocarbon group may or may not have a substituent. Examples of the substituent include alkyl groups such as methyl, ethyl, butyl, and t-butyl groups, alkoxy groups such as methoxy, ethoxy, butoxy, and t-butoxy groups, aryl groups such as phenyl and naphthyl groups, hydroxyl groups, amino groups, and halogen atoms. The aromatic hydrocarbon group may have two or more substituents, and in such cases, the substituents may be the same or different. When the aromatic hydrocarbon group has a substituent, the total number of carbon atoms contained in the aromatic hydrocarbon group and the substituent is preferably 6 to 18. When the aromatic hydrocarbon group has a substituent, the position of the substituent is not particularly limited.

Specific examples of aromatic hydrocarbon groups having 6 to 18 carbon atoms include phenyl, 1-naphthyl, 2-naphthyl, tolyl, dimethylphenyl, ethylphenyl, butylphenyl, t-butylphenyl, methoxyphenyl, ethoxyphenyl, butoxyphenyl, and t-butoxyphenyl. The position of the substituent in these aromatic hydrocarbon groups may be any of the ortho, meta, and para positions. From the viewpoint of fluidity, unsubstituted aryl groups having 6 to 12 carbon atoms or 6 to 12 carbon atoms including the substituent are preferred, unsubstituted aryl groups having 6 to 10 carbon atoms or 6 to 10 carbon atoms including the substituent are more preferred, and phenyl, p-tolyl, and p-methoxyphenyl groups are even more preferred.

The term "two or more of R ¹ to R ³ may be bonded to each other to form a cyclic structure" described as R ¹ to R ³ in general formula (I-1) means that two or three of R ¹ to R ³ are bonded to form a divalent or trivalent hydrocarbon group as a whole. In this case, examples of R ¹ to R ³ include substituents that can form a cyclic structure when bonded to a phosphorus atom, such as alkylene groups such as ethylene, propylene, butylene, pentylene, and hexylene, alkenylene groups such as ethylenylene, propyleneylene, and butyleneylene, aralkylene groups such as methylenephenylene, and arylene groups such as phenylene, naphthylene, and anthracenylene. These substituents may be further substituted with an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, a hydroxyl group, a halogen atom, or the like.

The "organic group having 1 to 18 carbon atoms" described as ^R4 to ^R7 in the above general formula (I-1) is meant to include an aliphatic hydrocarbon group, an aromatic hydrocarbon group, an aliphatic hydrocarbonoxy group, an aromatic hydrocarbonoxy group, an acyl group, a hydrocarbonoxycarbonyl group, and an acyloxy group which have 1 to 18 carbon atoms and may be substituted or unsubstituted.

Examples of the aliphatic hydrocarbon group and aromatic hydrocarbon group include those mentioned above as examples of the aliphatic hydrocarbon group and aromatic hydrocarbon group represented by R ¹ to R ³ .

The above-mentioned aliphatic hydrocarbon oxy groups include oxy groups having a structure in which an oxygen atom is bonded to the above-mentioned aliphatic hydrocarbon groups, such as methoxy groups, ethoxy groups, propoxy groups, isopropoxy groups, n-butoxy groups, 2-butoxy groups, t-butoxy groups, cyclopropyloxy groups, cyclohexyloxy groups, cyclopentyloxy groups, allyloxy groups, and vinyloxy groups, and these aliphatic hydrocarbon oxy groups are further substituted with alkyl groups, alkoxy groups, aryl groups, aryloxy groups, amino groups, hydroxyl groups, halogen atoms, etc.

The above aromatic hydrocarbon oxy groups include oxy groups having a structure in which an oxygen atom is bonded to the above-mentioned aromatic hydrocarbon groups, such as a phenoxy group, a methylphenoxy group, an ethylphenoxy group, a methoxyphenoxy group, a butoxyphenoxy group, and a phenoxyphenoxy group, and these aromatic hydrocarbon oxy groups are further substituted with an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, a halogen atom, etc.

The above-mentioned acyl group includes aliphatic hydrocarbon carbonyl groups such as formyl group, acetyl group, ethylcarbonyl group, butyryl group, cyclohexylcarbonyl group, and allylcarbonyl group, and aromatic hydrocarbon carbonyl groups such as phenylcarbonyl group and methylphenylcarbonyl group, and these aliphatic hydrocarbon carbonyl groups or aromatic hydrocarbon carbonyl groups further substituted with alkyl groups, alkoxy groups, aryl groups, aryloxy groups, amino groups, halogen atoms, etc.

The above-mentioned hydrocarbon oxycarbonyl groups include aliphatic hydrocarbon oxycarbonyl groups such as methoxycarbonyl groups, ethoxycarbonyl groups, butoxycarbonyl groups, allyloxycarbonyl groups, and cyclohexyloxycarbonyl groups; aromatic hydrocarbon oxycarbonyl groups such as phenoxycarbonyl groups and methylphenoxycarbonyl groups; and these aliphatic hydrocarbon carbonyloxy groups or aromatic hydrocarbon carbonyloxy groups further substituted with alkyl groups, alkoxy groups, aryl groups, aryloxy groups, amino groups, halogen atoms, etc.

Examples of the acyloxy group include aliphatic hydrocarbon carbonyloxy groups such as methylcarbonyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, allylcarbonyloxy group, and cyclohexylcarbonyloxy group, aromatic hydrocarbon carbonyloxy groups such as phenylcarbonyloxy group and methylphenylcarbonyloxy group, and these aliphatic hydrocarbon carbonyloxy groups or aromatic hydrocarbon carbonyloxy groups further substituted with an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, a halogen atom, etc.

The term "two or more R ^{4 to R 7 may be bonded together to form a cyclic structure" described as R 4 to R 7 in} the above general formula (I-1) means that two to four R ⁴ to R ⁷ may be bonded together to form a divalent to tetravalent organic group as a whole. In this case, R ⁴ to R ⁷ may include substituents ^capable of forming a cyclic structure, such as alkylene groups such as ethylene, propylene, butylene, pentylene, and hexylene, alkenylene groups such as ethylenylene, propyleneylene, and butyleneylene, aralkylene groups such as methylenephenylene, and arylene groups such as phenylene, naphthylene, and anthracenylene, and oxy or dioxy groups thereof. These substituents may be further substituted with an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, a hydroxyl group, a halogen atom, or the like.

R ⁴ to R ⁷ in the general formula (I-1) are not particularly limited. For example, each of them is preferably independently selected from a hydrogen atom, a hydroxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkoxy group, or a substituted or unsubstituted aryloxy group. Among them, from the viewpoint of the availability of raw materials, a hydrogen atom, a hydroxyl group, an aryl group unsubstituted or substituted with at least one selected from the group consisting of an alkyl group and an alkoxy group, or a linear or cyclic alkyl group is preferred. Examples of the aryl group unsubstituted or substituted with at least one selected from the group consisting of an alkyl group and an alkoxy group include a phenyl group, a p-tolyl group, an m-tolyl group, an o-tolyl group, and a p-methoxyphenyl group. Examples of the linear or cyclic alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a 2-butyl group, a t-butyl group, an octyl group, and a cyclohexyl group. From the viewpoint of curability, it is preferable that R ⁴ to R ⁷ are all hydrogen atoms, or that at least one of R ⁴ to R ⁷ is a hydroxyl group and the rest are all hydrogen atoms.

In general formula (I-1), more preferably, two or more of R ¹ to R ³ are alkyl groups having 1 to 18 carbon atoms or cycloalkyl groups having 3 to 18 carbon atoms, and R ⁴ to R ⁷ are all hydrogen atoms or at least one is a hydroxyl group and the rest are all hydrogen atoms. Even more preferably, R ¹ to R ³ are all alkyl groups having 1 to 18 carbon atoms or cycloalkyl groups having 3 to 18 carbon atoms, and R ⁴ to R ⁷ are all hydrogen atoms or at least one is a hydroxyl group and the rest are all hydrogen atoms.

From the viewpoint of rapid curing, the specific curing accelerator is preferably a compound represented by the following general formula (I-2).

In formula (I-2), R ¹ to R ³ each independently represent a hydrocarbon group having 1 to 18 carbon atoms, and two or more of R ¹ to R ³ may be bonded to each other to form a cyclic structure, and R ⁴ to R ⁶ each independently represent a hydrogen atom or an organic group having 1 to 18 carbon atoms, and two or more of R ⁴ to R ⁶ may be bonded to each other to form a cyclic structure.

Specific examples of R ¹ to R ⁶ in formula (I-2) are the same as the specific examples of R ¹ to R ⁶ in formula (I-1), and the preferred ranges are also the same.

Specific examples of specific curing accelerators include an addition reaction product of triphenylphosphine and 1,4-benzoquinone, an addition reaction product of tri-n-butylphosphine and 1,4-benzoquinone, an addition reaction product of tricyclohexylphosphine and 1,4-benzoquinone, an addition reaction product of dicyclohexylphenylphosphine and 1,4-benzoquinone, an addition reaction product of cyclohexyldiphenylphosphine and 1,4-benzoquinone, an addition reaction product of triisobutylphosphine and 1,4-benzoquinone, an addition reaction product of tricyclopentylphosphine and 1,4-benzoquinone, etc.

The specific curing accelerator can be obtained, for example, as an adduct of a tertiary phosphine compound and a quinone compound.
Specific examples of the tertiary phosphine compound include triphenylphosphine, tributylphosphine, dibutylphenylphosphine, butyldiphenylphosphine, ethyldiphenylphosphine, triphenylphosphine, tris(4-methylphenyl)phosphine, tris(4-ethylphenyl)phosphine, tris(4-propylphenyl)phosphine, tris(4-butylphenyl)phosphine, tris(isopropylphenyl)phosphine, tris(t-butylphenyl)phosphine, tris(2,4-dimethylphenyl)phosphine, tris(2,6-dimethylphenyl)phosphine, tris(2,4,6-trimethylphenyl)phosphine, tris(2,6-dimethyl-4-ethoxyphenyl)phosphine, tris(4-methoxyphenyl)phosphine, tris(4-ethoxyphenyl)phosphine, etc. From the viewpoint of moldability, triphenylphosphine and tributylphosphine are preferred.

Specific examples of quinone compounds include o-benzoquinone, p-benzoquinone, diphenoquinone, 1,4-naphthoquinone, anthraquinone, etc. From the viewpoints of moisture resistance and storage stability, p-benzoquinone is preferred.

The curable resin composition may contain a curing accelerator other than the phosphonium compound.
Specific examples of the curing accelerator other than the phosphonium compound include diazabicycloalkenes such as 1,5-diazabicyclo[4.3.0]nonene-5 (DBN) and 1,8-diazabicyclo[5.4.0]undecene-7 (DBU), cyclic amidine compounds such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, and 2-heptadecylimidazole; derivatives of the cyclic amidine compounds; phenol novolac salts of the cyclic amidine compounds or their derivatives; and combinations of these compounds with maleic anhydride, quinone compounds such as 1,4-benzoquinone, 2,5-toluquinone, 1,4-naphthoquinone, 2,3-dimethylbenzoquinone, 2,6-dimethylbenzoquinone, 2,3-dimethoxy-5-methyl-1,4-benzoquinone, 2,3-dimethoxy-1,4-benzoquinone, and phenyl-1,4-benzoquinone. compounds having intramolecular polarization obtained by adding a compound having a π bond, such as diazophenylmethane; cyclic amidinium compounds such as the tetraphenylborate salt of DBU, the tetraphenylborate salt of DBN, the tetraphenylborate salt of 2-ethyl-4-methylimidazole, and the tetraphenylborate salt of N-methylmorpholine; tertiary amine compounds such as pyridine, triethylamine, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol; derivatives of the above-mentioned tertiary amine compounds; and ammonium salt compounds such as tetra-n-butylammonium acetate, tetra-n-butylammonium phosphate, tetraethylammonium acetate, tetra-n-hexylammonium benzoate, and tetrapropylammonium hydroxide.

When the curable resin composition contains a specific curing accelerator as a curing accelerator, the content of the specific curing accelerator is preferably 30% by mass or more of the total curing accelerator, more preferably 50% by mass or more, and even more preferably 70% by mass or more.

When the curable resin composition contains a curing accelerator, the amount is preferably 0.1 to 30 parts by mass, and more preferably 1 to 15 parts by mass, per 100 parts by mass of the resin component. When the amount of the curing accelerator is 0.1 parts by mass or more per 100 parts by mass of the resin component, the composition tends to cure well in a short time. When the amount of the curing accelerator is 30 parts by mass or less per 100 parts by mass of the resin component, the curing speed is not too fast and a good molded product tends to be obtained.

(Inorganic filler)
The curable resin composition may contain an inorganic filler. In particular, when the curable resin composition is used as a sealing material for a semiconductor package, it is preferable that the curable resin composition contains an inorganic filler.

The type of inorganic filler is not particularly limited. Specific examples of inorganic materials include fused silica, crystalline silica, glass, alumina, calcium carbonate, zirconium silicate, calcium silicate, silicon nitride, aluminum nitride, boron nitride, beryllia, zirconia, zircon, fosterite, steatite, spinel, mullite, titania, talc, clay, and mica. Inorganic fillers having a flame retardant effect may be used. Examples of inorganic fillers having a flame retardant effect include aluminum hydroxide, magnesium hydroxide, composite metal hydroxides such as composite hydroxides of magnesium and zinc, and zinc borate. Among these, fused silica is preferred from the viewpoint of reducing the linear expansion coefficient, and alumina is preferred from the viewpoint of high thermal conductivity. The inorganic fillers may be used alone or in combination of two or more types. Examples of the state of the inorganic filler include powder, beads obtained by sphering powder, and fibers.

When the curable resin composition contains an inorganic filler, its content is not particularly limited. From the viewpoint of fluidity and strength, it is preferably 30% to 90% by volume of the entire curable resin composition, more preferably 35% to 80% by volume, and even more preferably 40% to 70% by volume. When the content of the inorganic filler is 30% by volume or more of the entire curable resin composition, the properties such as the thermal expansion coefficient, thermal conductivity, and elastic modulus of the cured product tend to be further improved. When the content of the inorganic filler is 90% by volume or less of the entire curable resin composition, the increase in viscosity of the curable resin composition is suppressed, and the fluidity is further improved, tending to result in better moldability.

The average particle diameter of the inorganic filler is not particularly limited. For example, the volume average particle diameter is preferably 0.2 μm to 10 μm, and more preferably 0.5 μm to 5 μm. If the volume average particle diameter is 0.2 μm or more, the increase in viscosity of the mold underfill resin composition tends to be further suppressed. If the volume average particle diameter is 10 μm or less, the filling ability into narrow gaps tends to be further improved. The volume average particle diameter of the inorganic filler can be measured as the volume average particle diameter (D50) using a laser diffraction scattering particle size distribution measuring device.

The volume average particle size of the inorganic filler in the curable resin composition or the cured product thereof can be measured by a known method. For example, the inorganic filler is extracted from the curable resin composition or the cured product using an organic solvent, nitric acid, aqua regia, etc., and thoroughly dispersed using an ultrasonic disperser or the like to prepare a dispersion. Using this dispersion, the volume average particle size of the inorganic filler can be measured from the volume-based particle size distribution measured using a laser diffraction scattering particle size distribution measuring device. Alternatively, the volume average particle size of the inorganic filler can be measured from the volume-based particle size distribution obtained by embedding the cured product in a transparent epoxy resin or the like, polishing the cross section obtained, and observing the cross section with a scanning electron microscope. Furthermore, the volume average particle size of the inorganic filler can be measured by continuously observing the two-dimensional cross section of the cured product using an FIB device (focused ion beam SEM) or the like and performing three-dimensional structural analysis.

From the viewpoint of the fluidity of the curable resin composition, the particle shape of the inorganic filler is preferably spherical rather than angular, and the particle size distribution of the inorganic filler is preferably wide.

[Various additives]
In addition to the above-mentioned components, the curable resin composition may contain various additives such as a coupling agent, an ion exchanger, a release agent, a flame retardant, a colorant, and a stress relaxation agent, as exemplified below. The curable resin composition may contain various additives known in the art, as necessary, in addition to the additives exemplified below.

(Coupling Agent)
When the curable resin composition contains an inorganic filler, it may contain a coupling agent to enhance adhesion between the resin component and the inorganic filler. Examples of the coupling agent include known coupling agents such as silane-based compounds such as epoxysilane, mercaptosilane, aminosilane, alkylsilane, ureidosilane, and vinylsilane, titanium-based compounds, aluminum chelate compounds, and aluminum/zirconium-based compounds.

When the curable resin composition contains a coupling agent, the amount of the coupling agent is preferably 0.05 parts by mass to 5 parts by mass, and more preferably 0.1 parts by mass to 2.5 parts by mass, per 100 parts by mass of the inorganic filler. When the amount of the coupling agent is 0.05 parts by mass or more per 100 parts by mass of the inorganic filler, the adhesion to the frame tends to be further improved. When the amount of the coupling agent is 5 parts by mass or less per 100 parts by mass of the inorganic filler, the moldability of the package tends to be further improved.

(Ion exchanger)
The curable resin composition may contain an ion exchanger. In particular, when the curable resin composition is used as an encapsulating molding material, it is preferable to contain an ion exchanger from the viewpoint of improving the moisture resistance and high-temperature storage characteristics of an electronic component device including an element to be encapsulated. The ion exchanger is not particularly limited, and a conventionally known ion exchanger can be used. Specifically, a hydrotalcite compound and a hydrous oxide of at least one element selected from the group consisting of magnesium, aluminum, titanium, zirconium, and bismuth can be mentioned. The ion exchanger may be used alone or in combination of two or more kinds. Among them, hydrotalcite represented by the following general formula (A) is preferable.

Mg _{(1-X) AlX} (OH) ₂ ( _CO3 ) _{X/ 2.mH2O} ...(A)
(0<X≦0.5, m is a positive number)

When the curable resin composition contains an ion exchanger, the content is not particularly limited as long as it is an amount sufficient to capture ions such as halogen ions. For example, the content is preferably 0.1 to 30 parts by mass, and more preferably 1 to 15 parts by mass, per 100 parts by mass of the resin component.

(Release agent)
The curable resin composition may contain a mold release agent from the viewpoint of obtaining good releasability from the mold during molding. The mold release agent is not particularly limited, and a conventionally known one may be used. Specific examples include carnauba wax, higher fatty acids such as montanic acid and stearic acid, higher fatty acid metal salts, ester waxes such as montanic acid esters, polyolefin waxes such as oxidized polyethylene and non-oxidized polyethylene, etc. The mold release agent may be used alone or in combination of two or more kinds.

When the curable resin composition contains a release agent, the amount is preferably 0.01 to 15 parts by mass, and more preferably 0.1 to 10 parts by mass, per 100 parts by mass of the resin component. When the amount of the release agent is 0.01 parts by mass or more per 100 parts by mass of the resin component, sufficient releasability tends to be obtained. When the amount is 15 parts by mass or less, better adhesion tends to be obtained.

(Flame retardants)
The curable resin composition may contain a flame retardant. The flame retardant is not particularly limited, and a conventionally known one may be used. Specific examples include organic or inorganic compounds containing halogen atoms, antimony atoms, nitrogen atoms, or phosphorus atoms, metal hydroxides, etc. The flame retardant may be used alone or in combination of two or more.

When the curable resin composition contains a flame retardant, the amount is not particularly limited as long as it is an amount sufficient to obtain the desired flame retardant effect. For example, it is preferably 1 to 300 parts by mass, and more preferably 2 to 150 parts by mass, per 100 parts by mass of the resin component.

(Coloring Agent)
The curable resin composition may further contain a colorant. Examples of the colorant include known colorants such as carbon black, organic dyes, organic pigments, titanium oxide, red lead, and red iron oxide. The content of the colorant can be appropriately selected depending on the purpose. The colorant may be used alone or in combination of two or more.

(Stress Relief Agent)
The curable resin composition may contain a stress relaxation agent such as silicone oil or silicone rubber particles. By containing a stress relaxation agent, it is possible to further reduce the warpage deformation of the package and the occurrence of package cracks. Examples of the stress relaxation agent include known stress relaxation agents (flexible agents) that are generally used. Specifically, examples of the stress relaxation agent include thermoplastic elastomers such as silicone-based, styrene-based, olefin-based, urethane-based, polyester-based, polyether-based, polyamide-based, and polybutadiene-based elastomers, rubber particles such as NR (natural rubber), NBR (acrylonitrile-butadiene rubber), acrylic rubber, urethane rubber, and silicone powder, and rubber particles having a core-shell structure such as methyl methacrylate-styrene-butadiene copolymer (MBS), methyl methacrylate-silicone copolymer, and methyl methacrylate-butyl acrylate copolymer. The stress relaxation agent may be used alone or in combination of two or more types. Among them, silicone-based stress relaxation agents are preferred. Examples of the silicone-based stress relaxation agent include those having an epoxy group, those having an amino group, and those modified with polyether.

(Method of preparing curable resin composition)
The method for preparing the curable resin composition is not particularly limited. A typical method is to thoroughly mix a predetermined amount of components with a mixer or the like, melt-knead the components with a mixing roll, an extruder, or the like, cool, and pulverize the components. More specifically, for example, a method is to uniformly stir and mix a predetermined amount of the components described above, knead the components with a kneader, roll, extruder, or the like that has been heated to 70°C to 140°C, cool, and pulverize the components.

The curable resin composition is preferably solid at room temperature and normal pressure (e.g., 25°C, atmospheric pressure). When the curable resin composition is solid, the shape is not particularly limited, and examples include powder, granules, and tablets. When the curable resin composition is in tablet form, it is preferable from the viewpoint of handleability that the dimensions and mass are set to be suitable for the molding conditions of the package.

<Electronic component device>
An electronic component device according to one embodiment of the present disclosure includes an element and a cured product of the above-described curable resin composition that encapsulates the element.
Examples of electronic component devices include devices obtained by mounting elements (active elements such as semiconductor chips, transistors, diodes, and thyristors, and passive elements such as capacitors, resistors, and coils) on a support member such as a lead frame, a pre-wired tape carrier, a wiring board, glass, a silicon wafer, or an organic substrate, and then sealing the resulting element portion with a curable resin composition.
More specifically, the following packages are available: DIP (Dual Inline Package), PLCC (Plastic Leaded Chip Carrier), QFP (Quad Flat Package), SOP (Small Outline Package), SOJ (Small Outline J-lead package), TSOP (Thin Small Outline Package), TQFP (Thin Quad Flat Package), etc., which have a structure in which an element is fixed on a lead frame, and terminals of the element such as bonding pads and leads are connected by wire bonding, bumps, etc., and then sealed by transfer molding or the like using a curable resin composition. General resin-sealed ICs such as TCP (Tape Carrier Package); TCP (Tape Carrier Package) having a structure in which an element connected to a tape carrier by a bump is sealed with a curable resin composition; COB (Chip On Board) module, hybrid IC, multi-chip module, etc. having a structure in which an element connected to wiring formed on a support member by wire bonding, flip chip bonding, solder, etc. is sealed with a curable resin composition; BGA (Ball Grid Array), CSP (Chip Size Package), MCP (Multi Chip Package), etc. having a structure in which an element is mounted on the surface of a support member having a terminal for wiring board connection formed on the back side, and the element and the wiring formed on the support member are connected by bump or wire bonding, and then the element is sealed with a curable resin composition. In addition, the curable resin composition can be suitably used in printed wiring boards.

Methods for encapsulating electronic device components using a curable resin composition include low-pressure transfer molding, injection molding, and compression molding. Of these, low-pressure transfer molding is the most common.

The above embodiment will be explained in detail below using examples, but the scope of the above embodiment is not limited to these examples.

[Preparation of Curable Resin Composition]
The following materials were mixed in the compositions (parts by mass) shown in Tables 1 and 2, and roll kneaded at a kneading temperature of 80° C. for a kneading time of 15 minutes to prepare the curable resin compositions of Examples 1 to 15 and Comparative Examples 1 to 8.

(Epoxy resin)
Epoxy resin 1: Biphenyl type epoxy resin having an epoxy equivalent of 196 g/eq and a melting point of 106° C. (Mitsubishi Chemical Corporation, product name "YX-4000H")
Epoxy resin 2: styrene-modified phenol novolac type epoxy resin having an epoxy equivalent of 282 g/eq and a softening point of 59° C. (Nippon Steel Sumikin Chemical Co., Ltd., product name "YDAN-1000-10C")
Epoxy resin 3: Methoxynaphthalene-cresol formaldehyde co-condensation type epoxy resin having an epoxy equivalent of 250 g/eq and a softening point of 58° C. (DIC Corporation, product name "HP-5000")
Epoxy resin 4: biphenylene skeleton-containing aralkyl type epoxy resin having an epoxy equivalent of 282 g/eq and a softening point of 56° C. (Nippon Kayaku Co., Ltd., product name "NC-3000")

(Comparative Curing Agent)
Curing agent A: Phenol aralkyl resin with a hydroxyl equivalent of 176 g/eq and a softening point of 70° C. (Meiwa Kasei Co., Ltd., product name "MEH-7800")
Curing agent B: a biphenyl skeleton type phenol aralkyl resin having a hydroxyl equivalent of 199 g/eq and a softening point of 89° C. (Meiwa Kasei Co., Ltd., product name "MEH-7851")

(Example Curing Agent)
Specific phenol novolak resin 1: A novolak resin having a hydroxyl equivalent of ²²³ g/eq and a viscosity of 19.3 Pa·s at 25°C, obtained by polycondensing an industrial cashew nut shell liquid, which is a mixture of general formulas (1-1) to (1-3) in which R 2 is an aliphatic hydrocarbon group represented by group (A), and phenol with formaldehyde (Gunei Chemical Industry Co., Ltd., product name "ELP83H").
Specific phenol novolak resin 2: Industrial cashew nut shell liquid which is a mixture of general formulas (1-1) to (1-3) in which R ² is an aliphatic hydrocarbon group represented by group (A), a novolak resin having a hydroxyl equivalent of 209 g/eq and a viscosity of 14.0 Pa·s at 25°C, obtained by polycondensation of cresol and phenol with formaldehyde (Gunei Chemical Industry Co., Ltd., product name "ELPC80")
Specific phenol novolak resin 3: Industrial cashew nut shell liquid, which is a mixture of general formulas (1-1) to (1-3) in which R ² is an aliphatic hydrocarbon group represented by group (A), a novolak resin having a hydroxyl equivalent of 204 g/eq and a viscosity of 23.6 Pa·s at 25°C, obtained by polycondensation of cresol and phenol with formaldehyde (Gunei Chemical Industry Co., Ltd., product name "ELPC75")
Specific phenol novolak resin 4: A novolak resin having a hydroxyl equivalent of 204 g/eq and a viscosity of ^20.2 Pa·s at 25°C, obtained by polycondensing industrial cashew nut shell liquid, which is a mixture of general formulas (1-1) to (1-3) in which R 2 is an aliphatic hydrocarbon group represented by group (A), and cresol with formaldehyde (Gunei Chemical Industry Co., Ltd., product name "ELC75").

(Cure Accelerator)
Curing accelerator: Addition product of triphenylphosphine and 1,4-benzoquinone (inorganic filler)
Spherical fused silica (volume average particle size 17.5 μm, specific surface area 3.8 m ² /g)
(Coupling Agent)
Epoxy silane (γ-glycidoxypropyltrimethoxysilane)
(Coloring Agent)
Carbon black (Mitsubishi Chemical Corporation, product name "MA-100")
(Release agent)
Carnauba wax (Cerarica NODA Co., Ltd.)

[Evaluation of Curable Resin Composition]
The properties of the curable resin compositions prepared in Examples 1 to 15 and Comparative Examples 1 to 8 were evaluated by the following property tests. The evaluation results are shown in Tables 3 and 4. The curable resin compositions were molded using a transfer molding machine at a mold temperature of 175°C, a molding pressure of 6.9 MPa, and a curing time of 90 seconds, unless otherwise specified. In addition, post-curing was performed at 175°C for 5 hours, as necessary.

(1) Spiral flow
The curable resin composition was molded under the above conditions using a spiral flow measurement mold conforming to EMMI-1-66, and the flow distance (cm) was determined.

(2) Hot Hardness The curable resin composition was molded into a disk having a diameter of 50 mm and a thickness of 3 mm under the above conditions, and immediately after molding, the hot hardness was measured using a Shore D hardness tester (Ueshima Seisakusho Co., Ltd., HD-1120 (Type D)).

(3) 260°C shear adhesive strength
The curable resin composition was molded under the above conditions onto a copper alloy plate (Pd-PPF) with a bottom diameter of 4 mm, a top diameter of 3 mm, and a height of 4 mm, and post-cured under the above conditions. Thereafter, the shear adhesive strength (MPa) was measured at a shear rate of 50 μm/s using a bond tester (Daisi Japan, Series 4000) while maintaining the temperature of the copper plate at 260° C.

(4) Water Absorption The disk molded in (2) above was post-cured under the above conditions. The disk was then left for 168 hours under conditions of 85°C and 60% RH, and the mass change before and after leaving was measured. The water absorption was calculated from the measurement results using the following formula.
Water absorption rate (mass%)=(mass of disk after standing−mass of disk before standing)/mass of disk before standing×100

(5) Reflow resistance
An 80-pin flat package (QFP) (lead frame material: copper alloy (Pd-PPF)) with external dimensions of 20 mm x 14 mm x 2 mm and a silicon chip of 8 mm x 10 mm x 0.4 mm was molded using the curable resin composition under the above conditions and post-cured under the above conditions. The obtained package was humidified for 168 hours under conditions of 85 ° C. and 60% RH. Thereafter, reflow treatment was performed under conditions of a predetermined temperature (250 ° C., 260 ° C., 270 ° C.) and 10 seconds, and the presence or absence of cracks on the outside of the package was observed visually, and the presence or absence of peeling inside the package was observed with an ultrasonic flaw detector (HYE-FOCUS, manufactured by Hitachi Construction Machinery Co., Ltd.). Reflow resistance was evaluated by the sum of the number of packages in which either cracks or peeling occurred out of the number of test packages (10).

As shown in Tables 3 and 4, Examples 1 to 15, which contain specific phenol novolac resins 1 to 4, have improved adhesion to metal (Pd-PPF) and improved reflow resistance compared to Comparative Examples 1 to 8, which do not contain specific phenol novolac resins.

Claims (6)

It is a powder, granule or tablet-like solid at 25°C and atmospheric pressure, and contains an epoxy resin and a hardener,
The epoxy resin is a solid at 25° C. and atmospheric pressure;
The hardener contains a phenol novolac resin containing a structural unit derived from cashew nut shell liquid and a phenol hardener that is solid at 25° C. and atmospheric pressure,
The amount of the phenol novolac resin is 3% to 50% on an equivalent basis based on the total amount of the curing agent. The curable resin composition according to claim 1, wherein the hydroxyl equivalent of the phenol novolac resin is 70 g/eq to 223 g/eq. The curable resin composition according to claim 1 or 2, wherein the phenol novolac resin further contains structural units derived from a phenolic compound other than cashew nut shell liquid. The curable resin composition according to any one of claims 1 to 3, wherein the phenol curing agent comprises an aralkyl-type phenol resin . The curable resin composition according to any one of claims 1 to 4, for use as a sealing material for electronic component devices. An electronic component device comprising an element and a cured product of the curable resin composition according to any one of claims 1 to 5 that encapsulates the element.