JP2024086365A - Curable resin composition and electronic component device - Google Patents

Abstract

[Problem] To provide a curable resin composition that prevents peeling from a lead frame even when the cured product absorbs moisture under conditions of 85°C and 85% RH, and an electronic component device that includes an element encapsulated with this curable resin composition.
[Solution] A curable resin composition which, when cured, has an elastic modulus of 400 MPa or less at 260°C, a linear expansion coefficient of 32 ppm/°C or more between 180°C and 200°C when cured, and an adhesive strength of the cured product to Ag (silver) of 0.45 MPa or more after treatment at 85°C and 85% RH.
[Selection diagram] None

Description

This disclosure relates to a curable resin composition and an electronic component device.

In recent years, semiconductor elements have become more densely packed. As a result, surface-mounted packages have become the mainstream for resin-sealed semiconductor devices, replacing the conventional pin-insertion packages. Surface-mounted ICs (Integrated Circuits), LSIs (Large Scale Integration), etc. are packaged in thin, small packages to increase mounting density and reduce mounting height. As a result, the area occupied by the elements in the package has increased, and the thickness of the package has become very thin.

Furthermore, these packages are mounted differently from pin insertion type packages, in that the pins of the pin insertion type packages 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, since surface-mounted ICs are temporarily attached to the surface of a wiring board and processed in a solder bath, reflow device, etc., the package is directly exposed to the soldering temperature (reflow temperature). As a result, if the package has absorbed moisture, the absorbed moisture vaporizes during reflow, and the generated vapor pressure acts as peeling stress, causing peeling between the sealing material and supporting members such as elements and lead frames, causing package cracks, poor electrical characteristics, etc. Therefore, there is a demand for the development of a sealing material that has excellent adhesion to supporting members and therefore excellent solder heat resistance (reflow resistance).

Patent Document 1 proposes a curable resin composition containing an epoxy resin, a curing agent, a curing accelerator, an inorganic filler, and an alkoxysilane polymer having a specific structure as a sealing material having excellent reflow resistance.
Furthermore, in order to improve reflow resistance, for example, the surface of the lead frame is roughened before plating to improve adhesion to the sealing material.

JP 2008-111101 A

There is a need for the development of an encapsulating material that is prevented from peeling off from a lead frame even under more severe moisture absorption conditions.
The present disclosure has been made in consideration of the above-mentioned circumstances, and aims to provide a curable resin composition that suppresses peeling from a lead frame even when the cured product is subjected to moisture absorption under conditions of 85°C and 85% RH, and an electronic component device including an element encapsulated with this curable resin composition.

<1> A curable resin composition which, when cured, has an elastic modulus of 400 MPa or less at 260°C, a coefficient of linear expansion of 32 ppm/°C or more from 180°C to 200°C, and an adhesive strength of 0.45 MPa or more to Ag (silver) after treatment at 85°C and 85% RH.
<2> The curable resin composition according to <1>, having a spiral flow according to EMMI-1-66 of 100 cm or more.
<3> The curable resin composition according to <1> or <2>, wherein the cured product has a hot hardness of 56 or more.
<4> The curable resin composition according to any one of <1> to <3>, wherein the cured product has a hot strength of 3 MN/ ^m2 or more.
<5> An electronic component device comprising: an element; and a cured product of the curable resin composition according to any one of <1> to <4> that encapsulates the element.
<6> The electronic component device according to <5>, further comprising a lead frame on one surface of which the element is mounted.
<7> The electronic component device according to <6>, wherein the lead frame contains Ag.

According to the present disclosure, it is possible to provide a curable resin composition that suppresses peeling from a lead frame even when the cured product is subjected to moisture absorption under conditions of 85°C and 85% RH, and an electronic component device including an element encapsulated with this curable resin composition.

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

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 numerical ranges described in the present disclosure in a stepwise manner, the upper limit or lower limit of one numerical range may be replaced with the upper limit or lower limit of another numerical range described in a stepwise manner. In addition, in the numerical ranges described in the present disclosure, the upper limit or lower limit of the numerical range may be replaced with the value shown in the synthesis examples.
In the present disclosure, each component may contain multiple types of corresponding compounds. When multiple substances corresponding to each component are present in the composition, the content or amount of each component means the total content or amount of the multiple substances present in the composition, unless otherwise specified.
In the present disclosure, the particles corresponding to each component may include multiple types. When multiple types of particles corresponding to each component are present in the composition, the particle size of each component means the value for a mixture of the multiple types of particles present in the composition, unless otherwise specified.
In this disclosure, the term "lamination" refers to stacking layers, where two or more layers may be bonded together or two or more layers may be removable.
In the description of groups (atomic groups) in the present disclosure, the description without specifying whether substituted or unsubstituted includes those having a substituent as well as those having no substituent.
In the present disclosure, the number of structural units represents an integer value for a single molecule, but represents a rational number that is an average value for an aggregate of multiple types of molecules.
In the present disclosure, the number of carbon atoms means the total number of carbon atoms contained in an entire group, and represents the number of carbon atoms forming the skeleton of the group when the group has no substituents, and represents the total number obtained by adding the number of carbon atoms forming the skeleton of the group to the number of carbon atoms in the substituents when the group has a substituent.

In the present disclosure, the weight average molecular weight (Mw) is a value measured using the following GPC measuring device under the following measurement conditions, and converted using a calibration curve of standard polystyrene. However, for compounds whose Mw cannot be accurately measured by GPC due to their small molecular weight, the molecular weight calculated from the chemical structure of the compound is used as the Mw, Mn, or degree of polymerization of the compound.
The following is an example of a measuring device, and a calibration curve may be created using a 5-sample set of standard polystyrene ("PStQuick MP-H" and "PStQuick B", manufactured by Tosoh Corporation).

(GPC measuring device)
GPC device: High-speed GPC device "HCL-8320GPC", detector is differential refractometer or UV, manufactured by Tosoh Corporation Column: Column TSKgel SuperMultipore HZ-H (column length: 15 cm, column inner diameter: 4.6 mm), manufactured by Tosoh Corporation (measurement conditions)
Solvent: Tetrahydrofuran (THF)
Measurement temperature: 40°C
Flow rate: 0.35 mL/min Sample concentration: 10 mg/5 mL THF
Injection volume: 20 μL

<Curable resin composition>
The curable resin composition of the present disclosure has, when cured, a modulus of elasticity at 260°C of 400 MPa or less, a coefficient of linear expansion from 180°C to 200°C of 32 ppm/°C or more, and an adhesive strength of the cured product to Ag (silver) after treatment at 85°C and 85% RH of 0.45 MPa or more.
The curable resin composition of the present disclosure is suppressed from peeling off from the lead frame even when the curing agent is subjected to moisture absorption under conditions of 85° C. and 85% RH. The reason why the curable resin composition of the present disclosure exhibits the above-mentioned effect is not clear, but is presumed to be as follows.

If the cured product has an elastic modulus of 400 MPa or less at 260° C., the distortion stress between the lead frame and the cured product during reflow treatment is small, and peeling from the lead frame is suppressed.
In addition, it was previously thought that the smaller the linear expansion coefficient, the more likely it was to suppress peeling from the lead frame. However, in the curable resin composition of the present disclosure, it has been experimentally found that a linear expansion coefficient of the cured product at 180°C to 200°C of 32 ppm/°C or more is effective in suppressing peeling from the lead frame.
Furthermore, by setting the elastic modulus and linear expansion coefficient within the above ranges and making the adhesive strength of the cured product to Ag (silver) after treatment at 85°C and 85% RH 0.45 MPa or more, peeling from the lead frame is suppressed even when the product absorbs moisture under conditions of 85°C and 85% RH.

The elastic modulus of the cured product of the curable resin composition at 260° C. is 400 MPa or less, preferably 390 MPa or less, and more preferably 380 MPa or less.
From the viewpoint of protecting the chip from external forces, the elastic modulus at 260° C. is preferably 80 MPa or more, more preferably 100 MPa or more, even more preferably 120 MPa or more, and particularly preferably 170 MPa or more.

The elastic modulus of the cured product of the curable resin composition is measured using a viscoelasticity measuring device (e.g., RSAIII, manufactured by TA Instruments) at a span distance of 40 mm and a frequency of 1 Hz, by heating from 20°C to 300°C at a rate of 5°C/min using a three-point bending method, and the elastic modulus at 260°C is obtained. The cured product is prepared by the method described for the linear expansion coefficient. The cured product used has a rectangular shape with short sides of 5.1 mm, long sides of 20 mm, and a thickness of 2 mm.

The linear expansion coefficient of the cured product of the curable resin composition at 180°C to 200°C is 32 ppm/°C or more, preferably 34 ppm/°C or more, and more preferably 36 ppm/°C or more. From the viewpoint of approximating the linear expansion coefficient of other members used together with the cured product, the upper limit of the linear expansion coefficient is preferably 60 ppm/°C or less, more preferably 55 ppm/°C or less, even more preferably 50 ppm/°C or less, and particularly preferably 42 ppm/°C or less.

In the present disclosure, the linear expansion coefficient is the slope of the tangent at 180°C to 200°C when the distortion of the cured product is plotted against the temperature by thermal mechanical analysis (TMA) based on JIS K 7197:2012. The test load is 5 g and the heating rate is 5°C/min. The linear expansion coefficient can be measured using a thermomechanical analyzer (for example, TMA/SS6100 manufactured by Seiko Instruments Inc.).
The cured product is produced by molding the curable resin composition using a transfer molding machine under conditions of a mold temperature of 175° C., a molding pressure of 6.9 MPa, and a curing time of 90 seconds, and then post-curing for 5 hours at 175° C. The cured product has a rectangular shape with short sides of 5.1 mm, long sides of 20 mm, and a thickness of 2 mm.

The adhesive strength of the cured product of the curable resin composition to Ag (silver) is 0.45 MPa or more, preferably 0.50 MPa or more, and more preferably 0.55 MPa or more. There is no particular upper limit to the adhesive strength.

In measuring the adhesive strength of the cured product of the curable resin composition to Ag (silver), first, the curable resin composition is applied onto an Ag substrate, cured at 175°C for a curing time of 120 seconds, and then post-cured at 175°C for 5 hours to prepare a sample. The cured product of the sample has a shape of a short side of 3.0 mm, a long side of 3.5 mm, and a thickness of 2.9 mm. This sample is heated at 85°C and 85% RH for 168 hours, and then a shear strength test is performed using a bond tester device (e.g., Nordson, product name 4000 Optima) at 260°C, in which the tool of the device is applied to the cured product to measure the adhesive strength.

From the viewpoint of fluidity, the curable resin composition of the present disclosure preferably has a spiral flow measured by the following method of 100 cm or more, more preferably 120 cm or more, even more preferably 140 cm or more, and particularly preferably 160 cm or more.

Spiral flow is measured using a spiral flow measurement mold conforming to EMMI-1-66, and the flow distance is determined when the curable resin composition is molded under conditions of a mold temperature of 175°C, molding pressure of 6.9 MPa, and curing time of 90 seconds.

From the viewpoint of fluidity, the gel time of the curable resin composition at 175°C is preferably 15 seconds or more, more preferably 18 seconds or more, and even more preferably 21 seconds or more. From the viewpoint of curability, the gel time is preferably 50 seconds or less, more preferably 47 seconds or less, and even more preferably 44 seconds or less.

The gel time is measured from the time when 0.5 g of the thermosetting resin composition is placed on a hot plate preheated to 175°C until the resin loses its viscosity. It is preferable to heat the resin while periodically stirring it with a spatula or similar. "The resin loses its viscosity" refers to the phenomenon in which the resin breaks or is destroyed when kneaded with a spatula or similar.

The viscosity of the curable resin composition of the present disclosure at 175°C is preferably 0.01 Pa·s to 1000 Pa·s, more preferably 0.1 Pa·s to 200 Pa·s, even more preferably 1 Pa·s to 50 Pa·s, and particularly preferably 1 Pa·s to 20 Pa·s. The viscosity of the curable resin composition at 175°C is measured using a flow tester viscometer at a pressure of 1 MPa, a nozzle diameter of 1 mm, and a length of 10 mm.

From the viewpoint of heat resistance, etc., the glass transition temperature (Tg) of the cured product of the curable resin composition is preferably 80°C or higher, more preferably 85°C or higher, and even more preferably 90°C or higher. There is no particular upper limit for the Tg, and it may be 200°C or lower, or 180°C or lower.

In this disclosure, the glass transition temperature of the cured product is the temperature at the intersection of the tangent line at 40°C to 60°C and the tangent line at 200°C to 220°C obtained by measuring the linear expansion coefficient described above.

From the viewpoint of moldability, handling, etc. of the curable resin composition, the hot hardness of the cured product is preferably 56 or more, more preferably 58 or more, and even more preferably 60 or more. There is no particular upper limit to the hot hardness, and it may be 90 or less, 88 or less, or 85 or less.

The hot hardness of the cured product is measured at 175°C using a Shore hardness tester Type D (e.g., manufactured by Kobunshi Keiki Co., Ltd.) on a rectangular hot hardness measurement specimen measuring 4 mm x 80 mm x 10 mm. The test specimen is obtained by curing and molding the curable resin composition using a transfer molding machine and a disk mold under conditions of 175°C, 120 seconds, and a pressure of 7 MPa. The measurement is performed in the press immediately after the test specimen is made.

From the viewpoint of moldability, handling, etc. of the curable resin composition, the hot strength of the cured product is preferably ³ MN/m2 or more, more preferably 4 MN/ ^m2 or more, and even more preferably 5 MN/ ^m2 or more. There is no particular upper limit to the hot strength, and it may be ²⁰ MN/m2 or less, 18 MN/ ^m2 or less, or 16 MN/ ^m2 or less.

The hot strength of the cured product is measured using a load tester (e.g., Aiko Engineering Co., Ltd., tabletop tester 1301K) on a rectangular test piece for measuring hot strength, measuring 4 mm x 80 mm x 10 mm. The test piece is obtained by curing and molding the curable resin composition using a transfer molding machine and a disk mold under conditions of 175°C, 120 seconds, and a pressure of 7 MPa.

The following describes the various materials that the curable resin composition may contain.

(Epoxy resin)
The curable resin composition of the present disclosure preferably contains an epoxy resin. The epoxy resin may be used alone or in combination of two or more. At least one of the epoxy resins is preferably a triphenylmethane type epoxy resin having at least one selected from the group consisting of an alkyl group and an alkoxy group. Hereinafter, the "triphenylmethane type epoxy resin having at least one selected from the group consisting of an alkyl group and an alkoxy group" is also referred to as a "specific triphenylmethane type epoxy resin". The specific triphenylmethane type epoxy resin may be used alone or in combination of two or more.

The specific triphenylmethane type epoxy resin preferably has an alkyl group.
The alkyl group in the specific triphenylmethane type epoxy resin preferably has a carbon number of 1 to 20, more preferably 1 to 16, and even more preferably 1 to 10. The alkyl group may be linear, branched, or cyclic, but at least one of the alkyl groups is preferably branched and preferably contains a t-butyl group.

The alkoxy group in the specific triphenylmethane type epoxy resin preferably has 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and even more preferably 1 to 10 carbon atoms. The alkoxy group may be linear, branched, or cyclic.

The benzene ring contained in the specific triphenylmethane type epoxy resin preferably has two or more alkyl groups, and more preferably the benzene ring contained in the main chain has two or more alkyl groups. At least one of the two or more alkyl groups contained in the benzene ring is preferably a branched alkyl group, and the branched alkyl group is preferably arranged in the ortho position relative to the glycidyloxy group.

The specific triphenylmethane type epoxy resin may be an epoxy resin represented by the following formula (1):

In formula (1), each R independently represents an alkyl group or an alkoxy group, each i independently represents an integer from 1 to 3, and each k independently represents an integer from 0 to 4. n is an average value and is a number from 0 to 10.

Examples of the alkyl group and alkoxy group represented by R include those explained above.
i represents an integer of 1 to 3, preferably 2 or 3, and more preferably 2. When i is 2, at least one of R represented by the subscript i is preferably a branched alkyl group, more preferably a combination of a branched alkyl group and a linear alkyl group, for example, a combination of a t-butyl group and a methyl group. The t-butyl group and the methyl group may be located at any position on the benzene ring, but the t-butyl group is preferably located at the ortho position relative to the glycidyloxy group. In addition, the positional relationship between the t-butyl group and the methyl group may be any, and they may be located at any of the ortho position, meta position, and para position.
Each k independently represents an integer of 0 to 4, and is preferably 0.

A specific example of a specific triphenylmethane type epoxy resin is an epoxy resin represented by the following formula (2):

n is an average value and represents a number from 0 to 10.

The curable resin composition of the present disclosure may contain other epoxy resins besides the specific triphenylmethane type epoxy resin.
The other epoxy resin is not particularly limited in type as long as it has two or more epoxy groups in one molecule. Specific examples of the other epoxy resin are described below, but are not limited thereto.

Specifically, novolac-type epoxy resins (phenol novolac-type epoxy resins, orthocresol novolac-type epoxy resins, etc.) are obtained by epoxidizing novolac 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, 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 acid catalyst; triphenylmethane-type epoxy resins (but and specific triphenylmethane type epoxy resins are excluded); copolymer type epoxy resins obtained by epoxidizing novolak resins obtained by co-condensing the above 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 atom-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 esters which are glycidyl esters of polyvalent carboxylic acid compounds such as phthalic acid, isophthalic acid, and tetrahydrophthalic acid. diethyl ester type epoxy resins; glycidylamine type epoxy resins in which active hydrogen bonded 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 phenol resins; metaxylylene-modified epoxy resins which are glycidyl ethers of metaxylylene-modified phenol resins; terpenes Terpene-modified epoxy resins which are glycidyl ethers of modified phenolic resins; dicyclopentadiene-modified epoxy resins which are glycidyl ethers of dicyclopentadiene-modified phenolic resins; cyclopentadiene-modified epoxy resins which are glycidyl ethers of cyclopentadiene-modified phenolic resins; polycyclic aromatic ring-modified epoxy resins which are glycidyl ethers of polycyclic aromatic ring-modified phenolic resins; naphthalene-type epoxy resins which are glycidyl ethers of naphthalene ring-containing phenolic 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 phenolic resins such as phenol aralkyl resins and naphthol aralkyl resins; and the like. Furthermore, aminophenol-type epoxy resins which are glycidyl ethers of aminophenols are also included as epoxy resins. These epoxy resins may be used alone or in combination of two or more.

Among the above epoxy resins, it is preferable to include a biphenyl type epoxy resin from the viewpoint of the adhesiveness of the curable resin composition of the present disclosure to the lead frame and the balance between heat resistance and fluidity.

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.

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.

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.

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.

There are no particular limitations on the sulfur-containing epoxy resin, so long as it is an epoxy resin that contains a sulfur atom. For example, there is an epoxy resin represented by the following general formula (V).

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.

There are no particular limitations on the novolac epoxy resin, so long as it is an epoxy resin obtained by epoxidizing a novolac phenolic resin. For example, an epoxy resin represented by the following general formula (VI) can be used.

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) can be mentioned.

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.

Other triphenylmethane type epoxy resins besides the specific triphenylmethane type epoxy resins include triphenylmethane type epoxy resins that do not have alkyl groups or alkoxy groups.

The copolymerized epoxy resin obtained by epoxidizing a novolak 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 represented by the following general formula (IX) can be mentioned.

In formula (IX), R ¹⁹ to R ²¹ represent monovalent organic groups 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 and 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 R ¹⁹ to R ²¹ , i, j, and k are the same as the definitions of R ¹⁹ to R ²¹ , i, j, and k 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, is also preferred. For example, an epoxy resin represented by the following general formula is included. 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 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. 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 an epoxy resin represented by the following general formulas (X) and (XI) is more preferred.

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 l is independently an integer of 0 to 4. Each n is an average value, and is independently a number of 0 to 10.

With regard to R ⁸ to R ²¹ and R ³⁷ to R ⁴¹ in the above general formulae ((II) to (VII), (IX) to (XI), "each may be the same or different" means, for example, that all of the 8 to 88 R ^8s in formula (II) may be the same or different. With regard to the other R ⁹ to R ²¹ and R ³⁷ to R ⁴¹ as well, it means that each of the numbers contained in the formula may be the same or different. Furthermore, R ⁸ to R ²¹ and R ³⁷ to R ⁴¹ may be the same or different. For example, all of R ⁹ and R ¹⁰ may be the same or different.
In addition, the monovalent organic group having 1 to 18 carbon atoms in the general formulae (III) to (VII) and (IX) to (XI) is preferably an alkyl group or an aryl group.

In the above general formulas (II) to (VII) and (IX) to (XI), n is an average value, and each is preferably independently in the range of 0 to 10. When 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 other epoxy resin is not particularly limited. From the viewpoint of the balance of various properties such as moldability, heat resistance, and electrical reliability, the epoxy equivalent of the other epoxy resin is preferably 40 g/eq to 1000 g/eq, more preferably 45 g/eq to 500 g/eq, and even more preferably 50 g/eq to 350 g/eq.
The epoxy equivalent of other epoxy resins is a value measured by a method in accordance with JIS K 7236:2009.

The other epoxy resin may be a solid or a liquid at 25° C. When the epoxy resin is a solid at 25° C., the softening point or melting point of the epoxy resin is not particularly limited. From the viewpoint of the balance between moldability and heat resistance, the softening point or melting point of the other epoxy resin is preferably 40° C. to 180° C. Furthermore, from the viewpoint of handleability during the production of the curable resin composition, the softening point or melting point of the epoxy resin is preferably 50° C. to 130° C.
In the present disclosure, the softening point refers to a value measured by the ring and ball method of JIS K 7234:1986.
In the present disclosure, the melting point refers to a value measured in accordance with the visual observation method of JIS K 0064:1992.

From the viewpoint of the balance between moldability and heat resistance, the Mw of the other epoxy resins is preferably 550 to 1050, and more preferably 650 to 950.

The ratio of the specific triphenylmethane type epoxy resin to the total amount of 100 parts by mass of the epoxy resin in the curable resin composition is preferably 15 parts by mass or more, more preferably 20 parts by mass or more, and even more preferably 25 parts by mass or more. The upper limit of this ratio is not particularly limited, but may be 95 parts by mass or less, 90 parts by mass or less, or 85 parts by mass or less.

From the viewpoints of strength, fluidity, heat resistance, moldability, etc., the total content of the epoxy resin in the curable resin composition is preferably 0.5% by mass to 60% by mass, more preferably 2% by mass to 50% by mass, and even more preferably 3% by mass to 45% by mass.

(Hardening agent)
The curable resin composition of the present disclosure preferably contains a curing agent. The type of the curing agent is not particularly limited and can be selected from those generally used as components of curable resin compositions. The curing agent may be used alone or in combination of two or more types.
In the present disclosure, a curing agent is required to have a structure that can react with the epoxy resin contained in the curable resin composition and cure the curable resin composition, and even a compound that is contained in a small amount and contributes little to the curing reaction of the curable resin composition is considered to be included in the curing agent.

Examples of the curing agent include a phenol-based curing agent, an amine-based curing agent, an acid anhydride-based curing agent, a polymercaptan-based curing agent, a polyaminoamide-based curing agent, an isocyanate-based curing agent, and a blocked isocyanate-based curing agent.
Among these, from the viewpoint of heat resistance, the curing agent is preferably a phenol-based curing agent or an amine-based curing agent.Furthermore, from the viewpoint of adhesion of the curable resin composition of the present disclosure to a lead frame and from the viewpoint of heat resistance, the curing agent is preferably a phenol-based curing agent.

Examples of phenol-based curing agents include phenol resins and polyhydric phenol compounds having two or more phenolic hydroxyl groups in one molecule. Specifically, polyhydric phenol compounds such as resorcin, catechol, bisphenol A, bisphenol F, and substituted or unsubstituted biphenol; novolac-type phenol 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, and aminophenol, and naphthol compounds such as α-naphthol, β-naphthol, and dihydroxynaphthalene, with aldehyde compounds such as formaldehyde, acetaldehyde, and propionaldehyde under an acid catalyst; phenolic compounds synthesized from the above-mentioned phenolic compounds and dimethoxyparaxylene, bis(methoxymethyl)biphenyl, and the like; Examples of the phenolic curing agent include aralkyl-type phenolic resins such as nol aralkyl resins and naphthol aralkyl resins; 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.

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 triphenylmethane-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.

From the viewpoint of adhesion to a lead frame and heat resistance of the curable resin composition of the present disclosure, the aralkyl phenol resin is preferably a phenol resin represented by general formula (XIII).
From the viewpoint of adhesion to the lead frame and heat resistance of the curable resin composition of the present disclosure, it is preferable that i and k are both 0 in general formula (XIII).

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) can be used.

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 using an aromatic aldehyde compound as a raw material. For example, a phenolic resin represented by the following general formula (XVI) is preferred.

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

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 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.

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 "each may be all the same or different" for R ²² to R ³⁶ in the above general formulas (XII) to (XVIII) means, for example, that 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 also mean that the respective numbers contained in the formula may all be the same or different from each other. In addition, R ²² to R ³⁶ may each be the same or different. For example, R ²² and R ²³ may all be the same or different, and R ³⁰ and R ³¹ may all be the same or different.

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 filling defects, deformation of the bonding wire (gold wire connecting the element and the lead), etc. will occur. The average n in one molecule is preferably set in the range of 0 to 4.

Specific examples of amine-based curing agents include aliphatic amine compounds such as diethylenetriamine, triethylenetetramine, n-propylamine, 2-hydroxyethylaminopropylamine, cyclohexylamine, and 4,4'-diamino-dicyclohexylmethane; aromatic amine compounds such as diethyltoluenediamine, 3,3'-diethyl-4,4'-diaminodiphenylmethane, dimethylthiotoluenediamine, and 2-methylaniline; imidazole compounds such as imidazole, 2-methylimidazole, 2-ethylimidazole, and 2-isopropylimidazole; and imidazoline compounds such as imidazoline, 2-methylimidazoline, and 2-ethylimidazoline.

The functional group equivalent of the curing agent (hydroxyl group equivalent in the case of a phenol-based curing agent, active hydrogen equivalent in the case of an amine-based curing agent) is not particularly limited. From the viewpoint of the balance of various properties such as moldability, heat resistance, and electrical reliability, it is preferably 10 g/eq to 1000 g/eq, and more preferably 30 g/eq to 500 g/eq.
The hydroxyl equivalent in the case of a phenol-based curing agent refers to a value calculated based on a hydroxyl value measured in accordance with JIS K 0070: 1992. The active hydrogen equivalent in the case of an amine-based curing agent refers to a value calculated based on an amine value measured in accordance with JIS K 7237: 1995.

When the curing agent is solid at 25°C, its softening point or melting point is not particularly limited. From the viewpoint of moldability and heat resistance, the softening point or melting point of the curing agent is preferably 40°C to 180°C. Furthermore, from the viewpoint of handleability during the production of the curable resin composition, the softening point or melting point of the curing agent is preferably 50°C to 130°C.

When the curing agent is a phenol-based curing agent, the equivalent ratio of the phenolic hydroxyl groups (active hydrogen) of the phenol-based curing agent to the epoxy groups of the epoxy resin in the curable resin composition (the number of moles of the phenolic hydroxyl groups (active hydrogen) of the phenol-based curing agent/the number of moles of the epoxy groups of the epoxy resin) is not particularly limited, and can be, for example, 0.5 to 1.2, or alternatively 0.5 to 1.0, or alternatively 0.55 to 0.9, or alternatively 0.6 to 0.8.
When the equivalent ratio is 0.5 or more and less than 1.0, the adhesion between the cured product of the curable resin composition and the support member tends to be improved. Although the reason for this is not clear, the value of tan δ near the reflow temperature can be increased, and the internal stress of the cured resin during reflow tends to be alleviated.

When the curing agent includes a phenol-based curing agent, from the viewpoint of the adhesion of the curable resin composition of the present disclosure to the lead frame, the content of the phenol-based curing agent relative to the total mass of the curing agent is preferably 50% by mass to 100% by mass, more preferably 60% by mass to 100% by mass, and even more preferably 70% by mass to 100% by mass.

When the phenol-based curing agent contains an aralkyl-type phenolic resin, from the viewpoint of the adhesion of the curable resin composition of the present disclosure to the lead frame, the content of the aralkyl-type phenolic resin relative to the total mass of the phenol-based curing agent is more preferably 60% by mass to 100% by mass, and even more preferably 70% by mass to 100% by mass.

(Inorganic filler)
The curable resin composition of the present disclosure may contain an inorganic filler. When the curable resin composition contains an inorganic filler, the moisture absorption of the curable resin composition is reduced, and the strength in the cured state tends to be improved. When the curable resin composition is used as an encapsulant for a semiconductor package, it is preferable that the curable resin composition contains an inorganic filler.

The inorganic material constituting the inorganic filler is not particularly limited. Specific examples of the inorganic material include spherical silica, crystalline silica, glass, alumina, calcium carbonate, zirconium silicate, calcium silicate, silicon nitride, aluminum nitride, boron nitride, aluminum nitride, boehmite, beryllia, magnesium oxide, zirconia, zircon, fosterite, steatite, spinel, mullite, titania, talc, clay, mica, and titanates.
An inorganic filler made of an inorganic material having a flame retardant effect may be used, such as aluminum hydroxide, magnesium hydroxide, composite metal hydroxides such as a composite hydroxide of magnesium and zinc, and zinc borate.
The inorganic fillers may be used alone or in combination of two or more kinds.

The shape of the inorganic filler is not particularly limited, and examples include powder, spheres, fibers, etc. From the viewpoints of fluidity during molding of the curable resin composition and mold wear, a spherical shape is preferable.

The average particle size of the inorganic filler is not particularly limited. From the viewpoint of the balance between the viscosity, filling property, and the like of the curable resin composition, the volume average particle size of the inorganic filler is preferably 0.1 μm to 50 μm, more preferably 0.3 μm to 30 μm, and further preferably 0.5 μm to 25 μm.
The volume average particle diameter of the inorganic filler can be measured as a volume average particle diameter (D50) by a laser diffraction scattering particle size distribution measuring device.

The particle size of the inorganic filler may be top cut, may be top cut at 100 μm or less, may be top cut at 75 μm or less, or may be top cut at 53 μm or less.
The top cut particle size can be determined from the particle size distribution when the above volume average particle size (D50) is measured.

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

The content of the inorganic filler in the entire curable resin composition is preferably 68 vol % to 86 vol %, more preferably 70 vol % to 84 vol %, and even more preferably 72 vol % to 82 vol %.
When the content of the inorganic filler is 68% by volume or more of the entire curable resin composition, the properties of the cured product, such as the thermal expansion coefficient, thermal conductivity, and elastic modulus, tend to be further improved. When the content of the inorganic filler is 86% by volume or less of the entire curable resin composition, an increase in the viscosity of the curable resin composition is suppressed, and the flowability is further improved, tending to result in better moldability.

(Cure Accelerator)
The curable resin composition of the present disclosure may contain a curing accelerator. The type of the curing accelerator is not particularly limited and can be selected according to the type of epoxy resin, the desired properties of the curable resin composition, and the like. The curing accelerator may be used alone or in combination of two or more types. Specific examples of the curing accelerator are described below, but are not limited thereto.
Examples of the curing accelerator 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 the above compounds, when combined with maleic anhydride, 1,4-benzoquinone, quinone compounds such as 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; tetraphenylborate salt of DBU, tetraphenylborate salt of DBN, and tetraphenylborate salt of 2-ethyl-4-methylimidazole; cyclic amidinium compounds such as tetraphenylborate salts 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; ammonium salt compounds such as tetra-n-butylammonium acetate, tetra-n-butylammonium phosphate, tetraethylammonium acetate, tetra-n-hexylammonium benzoate, and tetrapropylammonium hydroxide; primary phosphines such as ethylphosphine and phenylphosphine, secondary phosphines such as dimethylphosphine and diphenylphosphine, triphenylphosphine, diphenyl(p-tolyl)phosphine, tris(alkylphenyl)phosphine, tris(alkoxyphenyl)phosphine, tris(alkylalkoxyphenyl)phosphine, tris(dialkylphenyl)phosphine, tris(trialkylphenyl)phosphine, tris(tetraalkylphenyl)phosphine, organic phosphines such as tertiary phosphines, such as tris(dialkoxyphenyl)phosphine, tris(trialkoxyphenyl)phosphine, tris(tetraalkoxyphenyl)phosphine, trialkylphosphine, dialkylarylphosphine, alkyldiarylphosphine, trinaphthylphosphine, and tris(benzyl)phosphine; phosphine compounds such as complexes of the above-mentioned organic phosphines with organoborons; complexes of the above-mentioned organic phosphines or the above-mentioned phosphine 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, phenyl-1,4-benzoquinone, and anthraquinone, and compounds having intramolecular polarization obtained by adding a compound having a π bond such as diazophenylmethane; , 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-t-butylphenol, 4-chloro-1-naphthol, 1-bromo-2-naphthol, 6-bromo-2-naphthol, 4-bromo-4'-hydroxybiphenyl, or other halogenated phenol compounds, followed by a dehydrohalogenation step, which have intramolecular polarization; tetra-substituted phosphonium compounds such as tetraphenylphosphonium, tetraphenylborate salts of tetra-substituted phosphonium such as tetraphenylphosphonium tetra-p-tolylborate, and salts of tetra-substituted phosphonium and phenol compounds; phosphobetaine compounds; and adducts of phosphonium compounds and silane compounds.
Suitable curing accelerators include triphenylphosphine, and adducts of triphenylphosphine with quinone compounds.

When the curable resin composition contains a curing accelerator, the content of the curing accelerator is preferably 0.1% by mass to 8% by mass, more preferably 0.3% by mass to 7% by mass, and even more preferably 0.5% by mass to 6% by mass, relative to 100 parts by mass of the total amount of the epoxy resin and the curing agent. By setting the content of the curing accelerator within the above numerical range, the curing speed of the curable resin composition of the present disclosure becomes an appropriate numerical value, making it easy to manufacture molded products.

(Various additives)
In addition to the above-mentioned components, the curable resin composition of the present disclosure may contain various additives such as a coupling agent, a stress relaxation agent, a release agent, a colorant, a flame retardant, an ion exchanger, etc. The curable resin composition of the present disclosure may also contain a siloxane compound having a structural unit having an epoxy group and an alkoxy group and having a degree of polymerization of 2. The curable resin composition may contain various additives well known in the art, as necessary, in addition to the additives exemplified below.

(Coupling Agent)
The curable resin composition of the present disclosure may contain a coupling agent. The type of coupling agent is not particularly limited, and a known coupling agent can be used. Examples of the coupling agent include a silane coupling agent and a titanium coupling agent. The coupling agent may be used alone or in combination of two or more types.

The silane coupling agent is not particularly limited, and examples thereof include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-ureidopropyltriethoxysilane, octenyltrimethoxysilane, glycidoxyoctyltrimethoxysilane, methacryloxyoctyltrimethoxysilane, and the like.

Examples of titanium coupling agents include isopropyl triisostearoyl titanate, isopropyl tris(dioctyl pyrophosphate) titanate, isopropyl tri(N-aminoethyl-aminoethyl) titanate, tetraoctyl bis(ditridecyl phosphite) titanate, tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl phosphite) titanate, bis(dioctyl pyrophosphate)oxyacetate titanate, bis(dioctyl pyrophosphate)ethylene titanate, isopropyl trioctanoyl titanate, isopropyl dimethacryl isostearoyl titanate, isopropyl tridodecyl benzenesulfonyl titanate, isopropyl isostearoyl diacryl titanate, isopropyl tri(dioctyl phosphate) titanate, isopropyl tricumyl phenyl titanate, and tetraisopropyl bis(dioctyl phosphite) titanate.

When the curable resin composition contains a coupling agent, the content of the coupling agent is preferably 0.001 parts by mass to 10 parts by mass, more preferably 0.01 parts by mass to 8 parts by mass, and even more preferably 0.05 parts by mass to 5 parts by mass, relative to 100 parts by mass of the inorganic filler contained in the curable resin composition, from the viewpoint of the adhesiveness at the interface between the epoxy resin and the inorganic filler.

(Stress Relief Agent)
The curable resin composition of the present disclosure may contain a stress relaxation agent such as silicone oil or silicone rubber particles. By containing a stress relaxation agent in the curable resin composition, 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, natural rubber (NR), acrylonitrile-butadiene copolymer (NBR), 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.

When the curable resin composition contains a stress relaxation agent, the content is preferably 10 to 60 parts by mass, and more preferably 20 to 50 parts by mass, per 100 parts by mass of the epoxy resin contained in the curable resin composition.

(Release agent)
When a mold is used during molding, the curable resin composition of the present disclosure may contain a release agent from the viewpoint of releasability from the mold. The release agent is not particularly limited, and a conventionally known one may be used. Examples of the release agent 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 release agent may be used alone or in combination of two or more types.

When the curable resin composition of the present disclosure contains a release agent, the content of the release agent is preferably 0.01 parts by mass to 15 parts by mass, and more preferably 0.1 parts by mass to 10 parts by mass, per 100 parts by mass of the epoxy resin contained in the curable resin composition. 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 releasability tends to be obtained.

(Coloring Agent)
The curable resin composition of the present disclosure may 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, etc. The colorant may be used alone or in combination of two or more types.

When the curable resin composition contains a colorant, the content is preferably 0.01% by mass to 5% by mass, and more preferably 0.05% by mass to 4% by mass.

(Flame retardants)
The curable resin composition of the present disclosure may contain a flame retardant. The flame retardant is not particularly limited, and a conventionally known one may be used. Examples of the flame retardant 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 kinds.

When the curable resin composition of the present disclosure contains a flame retardant, the content is not particularly limited as long as it is an amount sufficient to obtain the desired flame retardant effect. The content of the flame retardant is preferably 1 to 300 parts by mass, and more preferably 2 to 150 parts by mass, per 100 parts by mass of the epoxy resin contained in the curable resin composition.

(Ion exchanger)
The curable resin composition of the present disclosure may contain an ion exchanger. When the curable resin composition is used as an encapsulant for a semiconductor package, it is preferable to contain an inorganic 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. Specific examples include hydrotalcite compounds and hydrous oxides of at least one element selected from the group consisting of magnesium, aluminum, titanium, zirconium, and bismuth. The ion exchanger may be used alone or in combination of two or more. Specific examples of the ion exchanger include hydrotalcite represented by the following general formula (A).

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 of the present disclosure contains an ion exchanger, the content is not particularly limited as long as it is a sufficient amount to capture ions such as halogen ions. The content of the ion exchanger is preferably 0.1 parts by mass to 30 parts by mass, and more preferably 1 part by mass to 10 parts by mass, per 100 parts by mass of the epoxy resin contained in the curable resin composition.

(Method for producing curable resin composition)
The method for producing 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 the components, and pulverize the components. More specifically, the method is to uniformly stir and mix the components in a predetermined amount, knead the components with a kneader, roll, extruder, or the like that has been heated to 70°C to 140°C, cool the components, and pulverize the components.

The curable resin composition is preferably a solid at 25°C. When the curable resin composition is a solid at 25°C, the shape of the curable resin composition is not particularly limited, and examples of the shape 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.

(Uses of the curable resin composition)
The use of the curable resin composition of the present disclosure is not particularly limited, and can be used in various mounting techniques, for example, as a sealant for electronic component devices. The curable resin composition of the present disclosure can also be used in various applications in which it is desirable for the resin composition to have good fluidity and curability, such as resin molded bodies for various modules, resin molded bodies for motors, resin molded bodies mounted on vehicles, and sealants for electronic circuit protection materials.

<Electronic component device>
The electronic component device of the present disclosure includes an element and a cured product of the curable resin composition that encapsulates the element.

The electronic component device may include a support member on which an element is mounted.
Examples of the support member include a lead frame, a pre-wired tape carrier, a wiring board, glass, a silicon wafer, an organic substrate, etc. Among the above support members, a lead frame is preferred from the viewpoint of adhesion to the cured product of the curable resin composition. The lead frame may have an element mounted on one side thereof.

The lead frame may or may not have a roughened surface, but from the standpoint of manufacturing costs, a lead frame is preferred, and from the standpoint of adhesion, a roughened lead frame is preferred.
The surface roughening method is not particularly limited, and examples thereof include alkali treatment, silane coupling treatment, sand matt treatment, plasma treatment, and corona discharge treatment.

The lead frame preferably contains Ag, and may further contain Cu, etc.

Examples of elements included in electronic component devices include active elements such as silicon chips, transistors, diodes, and thyristors, and passive elements such as capacitors, resistors, and coils.

Specific configurations of the electronic component device include, but are not limited to, the following configurations.
(1) General resin-sealed ICs such as 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), and TQFP (Thin Quad Flat Package) that have a structure in which an element is fixed on a lead frame, and terminal parts of the element such as bonding pads and lead parts are connected using wire bonding, bumps, or the like, and then sealed using a curable resin composition;
(2) TCP (Tape Carrier Package) having a structure in which elements connected to a tape carrier using bumps are sealed using a curable resin composition;
(3) COB (Chip On Board) modules, hybrid ICs, multi-chip modules, etc., having a structure in which elements connected to wiring formed on a support member by wire bonding, flip chip bonding, solder, etc. are sealed with a curable resin composition;
(4) BGA (Ball Grid Array), CSP (Chip Size Package), MCP (Multi Chip Package), SiP (System in a Package), etc., which have a structure in which an element is mounted on the surface of a support member having terminals for connecting a wiring board formed on the back surface thereof, the element is connected to wiring formed on the support member using bumps or wire bonding, and then the element is sealed using a curable resin composition.

The method for encapsulating the element using the curable resin composition is not particularly limited, and any known method can be applied. For example, low-pressure transfer molding is a common encapsulation method, but injection molding, compression molding, casting, etc. may also be used.

The present disclosure will be specifically explained below with reference to examples, but the present disclosure is not limited to these examples. In addition, the numerical values in the table mean "parts by mass" unless otherwise specified.

[Examples 1-2 and Comparative Examples 1-2]
The materials shown in Table 1 were premixed (dry blended), kneaded for about 15 minutes with a biaxial roll (roll surface temperature: about 80° C.), cooled, and pulverized to produce a powdered curable resin composition. The equivalent ratio of the phenolic hydroxyl group (active hydrogen) of the phenol-based curing agent to the epoxy group of the epoxy resin was 0.7.

Details of the materials in Table 1 are as follows:

Epoxy resin A: biphenyl type, epoxy equivalent 192 g/eq
Epoxy resin B: sulfur atom-containing epoxy resin, epoxy equivalent 238 g/eq to 254 g/eq, melting point 116°C to 126°C
Epoxy resin C: triphenylmethane type (having no alkyl or alkoxy groups), epoxy equivalent 169 g/mol, softening point 60° C.
Epoxy resin D: orthocresol type, epoxy equivalent 200 g/eq
Epoxy resin E: a triphenylmethane type epoxy resin represented by the above formula (2), having an epoxy equivalent of 214 g/eq and a melting point of 85° C.

Hardener A: phenolic resin, hydroxyl equivalent 175 g/eq
Hardener B: Triphenylmethane type phenolic resin, hydroxyl equivalent 104 g/eq
Hardener C: alkyl-modified phenolic resin, hydroxyl equivalent 224 g/eq

Curing accelerator: 1,4-benzoquinone adduct of triphenylphosphine Inorganic filler: Spherical silica particles with a top cut of 75 μm and a volume average particle size of 19 μm

Coupling agent A: N-phenyl-3-aminopropyltrimethoxysilane Coupling agent B: 3-glycidoxypropyltrimethoxysilane Coupling agent C: 3-mercaptopropyltrimethoxysilane

Release agent: Montan acid ester and other ester waxes Colorant: Carbon black Ion exchanger: Hydrotalcite

Stress relaxation agent A: Methyl/phenyl polysiloxane compound, solid at 25°C Stress relaxation agent B: Triphenylphosphine oxide Stress relaxation agent C: Coumarone resin, softening point 100°C

<<Evaluation of Curable Resin Composition>>
The properties of the curable resin compositions prepared in the Examples and Comparative Examples were measured and evaluated by the following methods. The evaluation results are shown in Table 2.

<Spiral flow measurement>
The spiral flow of the curable resin composition was measured by the method described above.

<Gel time measurement>
The gel time of the curable resin composition was measured by the method described above.

<Measurement of Viscosity>
The viscosity of the curable resin composition at 175° C. was measured by the method described above.

<Measurement of linear expansion coefficient>
By the above-mentioned method, the thermal expansion coefficient of the cured product of the curable resin composition was measured at 180° C. to 200° C. The thermomechanical analyzer used was TMA/SS6100 manufactured by Seiko Instruments Inc.

<Glass transition temperature (Tg) of cured product>
The temperature at the intersection of the tangent line at 10° C. to 30° C. and the tangent line at 200° C. to 220° C., obtained by measuring the linear expansion coefficient, was taken as the glass transition temperature of the cured product.

<Measurement of Elastic Modulus>
By the above-mentioned method, the thermal expansion coefficient of the cured product of the curable resin composition was measured at 260° C. The viscoelasticity measuring device used was RSAIII manufactured by TA Instruments.

<Measurement of Adhesive Strength to Ag (Silver)>
The adhesive strength of the cured product of the curable resin composition to Ag (silver) was measured by the above-mentioned method. The measuring device used was a 4000 Optima product manufactured by Nordson Corporation.

<Measurement of hot hardness>
The hot hardness of the cured product of the curable resin composition was measured by the above-mentioned method. The measuring device used was a Shore hardness tester Type D manufactured by Kobunshi Keiki Co., Ltd.

<Measurement of heat strength>
The hot strength of the cured product of the curable resin composition was measured by the above-mentioned method. A tabletop tester 1301K manufactured by Aiko Engineering Co., Ltd. was used as the measuring device.

<Evaluation of peelability when absorbing high temperature and moisture>
An 80-pin flat package (lead frame material: AgCu) with external dimensions of 20 mm in length, 14 mm in width, and 2 mm in thickness was produced, which was equipped with a silicon chip (8 mm in length, 10 mm in width, and 0.4 mm in thickness) encapsulated using the cured product of the curable resin composition formed under the above conditions.
The package was heated under two conditions: 85° C., 85% RH for 168 hours (MSL1), and 85° C., 60% RH for 168 hours (MSL2).
Thereafter, a reflow treatment was performed for 10 seconds at 260° C., 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.) The peelability was evaluated based on the number of packages in which peeling occurred out of the number of test packages (16 packages).

As shown in Table 2, under moisture absorption conditions of 85°C and 60% RH (MSL2), no difference in peelability appears between the comparative examples and the examples, and it is clear that the invention of this disclosure would not have been easily conceived under normal moisture absorption conditions. Furthermore, under the severe moisture absorption conditions of 85°C and 85% RH (MSL1), it is clear that peeling is significantly suppressed in the examples compared to the comparative examples. In particular, in Examples 1 and 2, no packages experienced peeling even under the severe moisture absorption conditions of MSL1, demonstrating particularly excellent effects.

Claims (7)

A curable resin composition that has an elastic modulus of 400 MPa or less at 260°C when cured, a linear expansion coefficient of 32 ppm/°C or more between 180°C and 200°C when cured, and an adhesive strength of 0.45 MPa or more to Ag (silver) after treatment at 85°C and 85% RH. The curable resin composition according to claim 1, having a spiral flow according to EMMI-1-66 of 100 cm or more. The curable resin composition according to claim 1, which has a hot hardness of 56 or more when cured. The curable resin composition according to claim 1 , which has a hot strength of 3 MN/m ² or more when cured. An electronic component device comprising an element and a cured product of the curable resin composition according to any one of claims 1 to 4 that encapsulates the element. The electronic component device according to claim 5, further comprising a lead frame on one side of which the element is mounted. The electronic component device of claim 6 , wherein the lead frame comprises Ag.