Curable composition

Abstract

To provide a curable composition or the like capable of obtaining a cured product having high thermal conductivity and low elastic modulus.SOLUTION: A curable composition containing (A) a thermally conductive filler, (B) a silsesquioxane compound, and (C) a liquid polythiol compound, wherein when the component (B) does not contain an epoxy group-containing silsesquioxane compound having an epoxy group, the curable composition further contains (D) an epoxy resin, and when the component (B) contains an epoxy group-containing silsesquioxane compound, the curable composition contains or does not contain (D) an epoxy resin.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a curable composition, and further to a curable-composition-containing sheet, a circuit board, a semiconductor chip package, and an electronic component using the curable composition. [Background technology]

[0002] In recent years, electronic devices have become smaller and more sophisticated, and the mounting density of semiconductor elements on printed wiring boards has tended to increase. Coupled with the increasing functionality of the mounted semiconductor elements, there is a demand for technology to efficiently dissipate the heat generated by the semiconductor elements.

[0003] For example, Patent Document 1 discloses that heat is dissipated by using an insulating layer formed on a circuit board, the insulating layer being formed by curing a resin composition containing a resin and alumina that satisfies certain requirements. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-77123 Summary of the Invention [Problem to be solved by the invention]

[0005] Insulating layers are required to have not only high thermal conductivity but also low elastic modulus from the viewpoint of impact resistance, but conventional techniques have not necessarily been able to realize insulating layers with both high thermal conductivity and low elastic modulus that are fully satisfactory.

[0006] The present invention has been made in view of the above, and aims to provide a curable composition that can give a cured product having high thermal conductivity and low elastic modulus; and a curable-composition-containing sheet, a circuit board, a semiconductor chip package, and an electronic component that use the curable composition. [Means for solving the problem]

[0007] In order to achieve the object of the present invention, the present inventors conducted extensive research and found that by incorporating (A) a thermally conductive filler, (B) a silsesquioxane compound, and (C) a liquid polythiol, etc., it is possible to obtain a cured product with high thermal conductivity and low elastic modulus, and thus completed the present invention.

[0008] That is, the present invention includes the following. [1] (A) Thermally conductive filler, (B) a silsesquioxane compound, and (C) A curable composition containing a liquid polythiol compound, When the component (B) does not contain an epoxy group-containing silsesquioxane compound having an epoxy group, the curable composition further contains an epoxy resin (D), When the component (B) contains an epoxy group-containing silsesquioxane compound, the curable composition may contain (D) an epoxy resin. [2] The curable composition according to [1], wherein the content of component (A) is 20% by mass or more and 80% by mass or less, when the total amount of non-volatile components in the curable composition is 100% by mass. [3] The curable composition according to [1] or [2], wherein when the curable composition contains an epoxy group-containing silsesquioxane compound as component (B) and further contains an epoxy resin (D), the content of component (B) is 5% by mass or more and 65% by mass or less, when the total amount of non-volatile components in the curable composition is 100% by mass. [4] The curable composition according to [1] or [2], wherein the curable composition contains an epoxy group-containing silsesquioxane compound as component (B) but does not contain an epoxy resin (D), and the content of component (B) is 10% by mass or more and 65% by mass or less, when the total amount of non-volatile components in the curable composition is 100% by mass. [5] The curable composition according to any one of [1] to [4], wherein the content of component (C) is 5% by mass or more and 30% by mass or less, when the total amount of non-volatile components in the curable composition is 100% by mass. [6] The curable composition according to any one of [1] to [5], wherein the component (C) contains two or more thiol groups in one molecule. [7] A curable composition-containing sheet having a support and a curable composition layer provided on the support, the curable composition layer including the curable composition according to any one of [1] to [6]. [8] A circuit board comprising an insulating layer formed from a cured product of the curable composition according to any one of [1] to [6]. [9] A semiconductor chip package comprising a cured product of the curable composition according to any one of [1] to [6].

[10] An electronic component comprising: an electronic component; a cured product of the curable composition according to any one of [1] to [6] provided on the electronic component; and a heat dissipation member attached to the cured product. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a curable composition that can give a cured product having high thermal conductivity and low elastic modulus; and a curable-composition-containing sheet, a circuit board, a semiconductor chip package, and an electronic component that use the curable composition. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be described in detail below based on preferred embodiments. However, the present invention is not limited to the following embodiments and examples, and can be implemented with any modifications within the scope of the claims of the present invention and their equivalents. In the present invention, the content of each component in the curable composition is a value when the non-volatile components in the curable composition are 100 mass %, unless otherwise specified.

[0011] [Curable composition] The curable composition contains (A) a thermally conductive filler, (B) a silsesquioxane compound, and (C) a liquid polythiol compound. When component (B) does not contain an epoxy group-containing silsesquioxane compound having epoxy groups, the curable composition further contains (D) an epoxy resin. When component (B) contains an epoxy group-containing silsesquioxane compound, the curable composition may or may not contain (D) an epoxy resin. By containing these components, the curable composition can increase the thermal conductivity and decrease the elastic modulus of the cured product.

[0012] In addition to the components (A) to (D), the curable composition may further contain a curing accelerator (E) and an optional additive (F), as necessary. Each component contained in the curable composition will be described in detail below.

[0013] <(A) Thermally conductive filler> The curable composition contains a thermally conductive filler (A) as component (A). By including component (A) in the curable composition, a cured product (insulating layer) with high thermal conductivity can be obtained.

[0014] From the viewpoint of obtaining a cured product with high thermal conductivity, the thermal conductivity of the (A) thermally conductive filler is preferably 20 W / m K or more, more preferably 30 W / m K or more, even more preferably 50 W / m K or more, and even more preferably 100 W / m K or more. There is no particular upper limit, but it can be 1000 W / m K or less.

[0015] The material for component (A) is not particularly limited as long as its thermal conductivity is within the above range. Examples of materials for component (A) include silicon carbide, boron nitride, aluminum nitride, and aluminum oxide (alumina). Component (A) may be used alone or in combination of two or more types. Furthermore, two or more types of the same material may be used in combination. From the viewpoint of obtaining a cured product with high thermal conductivity, component (A) preferably contains one or more selected from silicon carbide, boron nitride, aluminum nitride, and aluminum oxide, and more preferably contains silicon carbide.

[0016] From the viewpoint of obtaining an insulating layer with excellent thermal conductivity and improving filling properties, the average particle size of component (A) is preferably 50 μm or less, more preferably 45 μm or less, and even more preferably 40 μm or less, and is preferably 1 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more, 20 μm or more, or 30 μm or more.

[0017] The average particle size of component (A) can be measured by a laser diffraction / scattering method based on Mie scattering theory. Specifically, a particle size distribution of the thermally conductive filler is created on a volume basis using a laser diffraction / scattering particle size distribution analyzer, and the median diameter is used as the average particle size. A preferred measurement sample is component (A) dispersed in water using ultrasonic waves. Examples of laser diffraction / scattering particle size distribution analyzers that can be used include the LA-500 manufactured by Horiba, Ltd. and the SALD2200 manufactured by Shimadzu Corporation.

[0018] The specific surface area of ​​component (A) is preferably 0.01 m from the viewpoint of obtaining a cured product with excellent thermal conductivity. 2 / g or more, more preferably 0.025m 2 / g or more, more preferably 0.05m 2 / g or more. The upper limit is preferably 30m 2 / g or less, more preferably 25m 2 / g or less, more preferably 20m 2 / g or less. The specific surface area of ​​component (A) can be measured by the nitrogen BET method. Specifically, it can be measured using an automatic specific surface area measuring device, such as the "Macsorb HM-1210" manufactured by Mountech Co., Ltd.

[0019] Component (A) may be a commercially available product, such as "PT-110A," "PT-120," "PT-350," "PTX-25," or "PTX-60" manufactured by MOMENTIVE Corporation, "ANF-S-30," "ANF-S-50," "ANF-A-01-F," or "ANF-A-05-F" manufactured by MARUWA Corporation, or "DAW-05" or "DAW-20" manufactured by Denka Company Limited.

[0020] From the viewpoint of improving moisture resistance and dispersibility, component (A) may be treated with one or more surface treatment agents such as an aminosilane coupling agent, an epoxysilane coupling agent, a mercaptosilane coupling agent, a silane coupling agent, an alkoxysilane compound, an organosilazane compound, or a titanate coupling agent. Examples of commercially available surface treatment agents include Shin-Etsu Chemical Co., Ltd.'s "KBM403" (3-glycidoxypropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM803" (3-mercaptopropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBE903" (3-aminopropyltriethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM5783" (N-phenyl-3-aminooctyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "SZ-31" (hexamethyldisilazane), Shin-Etsu Chemical Co., Ltd.'s "KBM103" (phenyltrimethoxysilane), and Shin-Etsu Chemical Co., Ltd.'s "KBM-4803" (long-chain epoxy-type silane coupling agent).

[0021] From the viewpoint of improving the dispersibility of component (A), the degree of surface treatment with the surface treatment agent is preferably 0.2 to 5 parts by mass, more preferably 0.2 to 3 parts by mass, and even more preferably 0.3 to 2 parts by mass, per 100 parts by mass of component (A).

[0022] The degree of surface treatment with the surface treatment agent can be evaluated by the amount of carbon per unit surface area of ​​component (A). From the viewpoint of improving the dispersibility of component (A), the amount of carbon per unit surface area of ​​component (A) is set to 0.02 mg / m 2 More than 0.1 mg / m is preferable. 2 More preferably, 0.2 mg / m or more 2 On the other hand, from the viewpoint of suppressing an increase in melt viscosity, it is more preferable that the content is 1 mg / m 2 Less than 0.8 mg / m is preferred 2 Less than 0.5 mg / m is more preferable. 2 The following is even more preferred:

[0023] The carbon content per unit surface area of ​​component (A) can be measured after the surface-treated component (A) is washed with a solvent (e.g., methyl ethyl ketone (MEK)). Specifically, a sufficient amount of MEK as a solvent is added to component (A) that has been surface-treated with a surface treatment agent, and ultrasonic cleaning is performed at 25°C for 5 minutes. The supernatant is removed, the solid content is dried, and then the carbon content per unit surface area of ​​component (A) can be measured using a carbon analyzer. An "EMIA-320V" manufactured by Horiba, Ltd. or the like can be used as the carbon analyzer.

[0024] From the viewpoint of obtaining a cured product with excellent thermal conductivity, the content of component (A) is preferably 20% by mass or more, more preferably 30% by mass or more, and even more preferably 40% by mass or more, based on 100% by mass of the nonvolatile components in the curable composition. The upper limit is preferably 80% by mass or less, more preferably 65% ​​by mass or less, and even more preferably 50% by mass or less. When the content of component (A) is within the above range, the thermal conductivity and elastic modulus can be effectively improved. Furthermore, when the content of component (A) is equal to or less than the above upper limit, the viscosity of the curable composition can be reduced, thereby improving workability and adhesiveness.

[0025] <(B) Silsesquioxane Compound> The curable composition contains a silsesquioxane compound (B) as component (B). By incorporating component (B) in combination with component (C), described below, into the curable composition, it becomes possible to obtain a cured product with excellent thermal conductivity and low elastic modulus. Generally, when phonon scattering is suppressed, the thermal conductivity of the cured product tends to increase. While the reason why the inclusion of component (B) improves the thermal conductivity of the cured product of the curable composition is unclear, it is presumed that the skeleton of component (B) suppresses phonon scattering. One type of component (B) may be used alone, or two or more types may be used in combination.

[0026] Component (B) can be a compound having a silsesquioxane structure, which is a structure in which one silicon atom is bonded to three oxygen atoms, and the oxygen atom is bonded to two silicon atoms, and is represented by the following structural formula (B-1): [ka] In the formula, each R independently represents an alkyl group, a hydroxy group, a glycidyl group, an epoxy group, a thiol group, an alkoxy group, or a (meth)acryloyl group; and n represents an integer of 4 to 20.

[0027] When the silsesquioxane structure contained in the component (B) has a structure in which at least one R represents a glycidyl group or an epoxy group, the component (B) is an epoxy-group-containing silsesquioxane compound having an epoxy group.

[0028] In the silsesquioxane structure contained in component (B), when all R independently represent a hydrocarbon group, a hydroxy group, a thiol group, an alkoxy group, or a (meth)acryloyl group, component (B) is a silsesquioxane compound that does not have an epoxy group. The (meth)acryloyl group includes a methacryloyl group, an acryloyl group, and a combination thereof.

[0029] When the curable composition of the present invention contains an epoxy group-containing silsesquioxane compound as component (B), it also contains an epoxy resin (D) described below.

[0030] When the curable composition of the present invention does not contain an epoxy group-containing silsesquioxane compound as component (B), it may or may not contain an epoxy resin (D) described below. However, from the viewpoint of significantly obtaining the effects of the present invention, it is preferable that the curable composition of the present invention contains an epoxy resin (D).

[0031] The alkyl group represented by R may be linear, branched, or cyclic. The alkyl group is preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, and further preferably a methyl group or an ethyl group.

[0032] The alkoxy group represented by R is preferably an alkoxy group having 1 to 6 carbon atoms, more preferably an alkoxy group having 1 to 3 carbon atoms, and even more preferably a methoxy group or an ethoxy group.

[0033] Among these, R is preferably a functional group capable of reacting with component (C), more preferably selected from a hydroxy group, a glycidyl group, an epoxy group, and a thiol group, even more preferably selected from a glycidyl group, an epoxy group, and a thiol group, and particularly preferably either an epoxy group or a thiol group.

[0034] n represents an integer of 4 to 20, and preferably an integer of 6 to 12.

[0035] In addition to the silsesquioxane structure, the component (B) may contain a structure represented by the following formula (B-2): When the component (B) contains a structure represented by formula (B-2), the structure represented by formula (B-2) is preferably present at a part of the terminal of the component (B). [ka] In the formula, R 1is the same as R in formula (B-1). * represents a bond to the silsesquioxane structure.

[0036] Examples of the silsesquioxane structure include a random structure, a ladder structure having a ladder skeleton, and a cage structure. The component (B) preferably has one or more structures selected from the random structure, ladder structure, and cage structure, more preferably has either a random structure or a cage structure, and even more preferably has a random structure.

[0037] A random structure refers to a structure in which the arrangement of silsesquioxane structures is irregular and incomplete. A typical random structure is a structure represented by the following formula (B-3). A typical ladder structure is a structure represented by the following formula (B-4). There are two types of cage structures: a fully condensed cage structure and an incompletely condensed cage structure. A fully condensed cage structure contains multiple cyclic structures composed of silsesquioxane structures, and these multiple cyclic structures form a closed space or can form a closed space after a reaction. An incompletely condensed cage structure refers to a structure in which at least one part of the fully condensed cage structure is not closed. Typical fully condensed cage structures include a T8 structure having eight silicon atoms represented by the following formula (B-5), a T10 structure having ten silicon atoms represented by the following formula (B-6), and a T12 structure having twelve silicon atoms represented by the following formula (B-7). A typical incompletely condensed cage structure is represented by the following formula (B-8): 2 is the same as R in formula (B-1), and * represents a bond to the silsesquioxane structure. [ka]

[0038] The identification of whether the component (B) has a random structure, a ladder structure, or a cage structure can be measured according to a known method. As a specific identification method, for example, it can be measured according to the method described in JP-A-2022-3126.

[0039] Component (B) can be synthesized by a known method. Alternatively, a commercially available product may be used as component (B). Examples of commercially available products of component (B) include "SQ-502-8" and "SQ-107" manufactured by Arakawa Chemical Industries, Ltd., and "AC-SQ-TA-100" and "AC-SQ-SI20" manufactured by Toagosei Co., Ltd.

[0040] The functional group equivalent of component (B) is preferably 170 g / eq. or more, more preferably 180 g / eq. or more, even more preferably 190 g / eq. or more, and is preferably 300 g / eq. or less, more preferably 290 g / eq. or less, even more preferably 280 g / eq. or less. Unless otherwise specified, the functional group equivalent refers to the mass of the resin containing one equivalent of functional group.

[0041] When the silsesquioxane compound does not contain epoxy groups and the compound has thiol groups, the thiol group equivalent of component (B) is preferably 170 g / eq. or more, more preferably 180 g / eq. or more, even more preferably 190 g / eq. or more, and preferably 220 g / eq. or less, more preferably 210 g / eq. or less, and even more preferably 200 g / eq. or less. "Thiol group equivalent" refers to the mass of a resin containing one equivalent of thiol groups, and can be measured by known methods, such as iodine solution titration using starch as an indicator.

[0042] The epoxy equivalent of the epoxy group-containing silsesquioxane compound is preferably 250 g / eq or more, more preferably 260 g / eq or more, even more preferably 270 g / eq or more, and is preferably 300 g / eq or less, more preferably 290 g / eq or less, even more preferably 280 g / eq or less. The epoxy equivalent can be measured in accordance with JIS K7236 and is the mass of a resin containing one equivalent of epoxy groups.

[0043] The weight average molecular weight of component (B) is preferably 100 to 50,000, more preferably 500 to 10,000, and even more preferably 1,000 to 10,000. Here, the weight average molecular weight of component (B) is a weight average molecular weight measured by gel permeation chromatography (GPC) in terms of polystyrene.

[0044] From the viewpoint of significantly achieving the effects of the present invention, the content of the component (B) is preferably 5% by mass or more, more preferably 15% by mass or more, and even more preferably 25% by mass or more, and is preferably 65% ​​by mass or less, more preferably 55% by mass or less, and even more preferably 45% by mass or less, based on 100% by mass of the non-volatile components in the curable composition.

[0045] When the component (B) does not contain an epoxy group-containing silsesquioxane compound, the content of the component (B), relative to 100 mass% of the non-volatile components in the curable composition, is preferably 5 mass% or more, more preferably 15 mass% or more, even more preferably 25 mass% or more, and is preferably 65 mass% or less, more preferably 55 mass% or less, even more preferably 45 mass% or less, from the viewpoint of significantly obtaining the effects of the present invention.

[0046] When component (B) contains an epoxy group-containing silsesquioxane compound and the curable composition contains component (D), which will be described later, the content of the epoxy group-containing silsesquioxane compound is, from the viewpoint of significantly obtaining the effects of the present invention, preferably 5% by mass or more, more preferably 15% by mass or more, and even more preferably 25% by mass or more, and is preferably 65% ​​by mass or less, more preferably 55% by mass or less, and even more preferably 45% by mass or less, based on 100% by mass of the non-volatile components in the curable composition.

[0047] When the component (B) contains an epoxy group-containing silsesquioxane compound and the curable composition does not contain the component (D) described below, the content of the epoxy group-containing silsesquioxane compound is, from the viewpoint of significantly obtaining the effects of the present invention, preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, and is preferably 65% ​​by mass or less, more preferably 55% by mass or less, even more preferably 45% by mass or less, based on 100% by mass of the non-volatile components in the curable composition.

[0048] <(C) Liquid polythiol compound> The curable composition contains a liquid polythiol compound (C) as component (C). This liquid polythiol compound (C) does not include compounds corresponding to the aforementioned component (B). By incorporating a combination of components (C) and (B) into the curable composition, the thermal conductivity of the cured product of the curable composition can be improved and the modulus of elasticity can be reduced. The component (C) may be used alone or in combination of two or more. In the present invention, "liquid" refers to fluidity at room temperature (20°C) and atmospheric pressure (0.1 MPa). Preferably, the viscosity measured using an E-type viscometer at atmospheric pressure, 25°C, and a cone rotation speed of 2.0 rpm is 200,000 mPa·s or less. An example of an E-type viscometer is the RE-85U E-type viscometer (cone rotor: 3°×R14) (manufactured by Toki Sangyo Co., Ltd.).

[0049] The component (C) can be a polythiol compound that has the function of reacting with the functional groups of the component (B) or the epoxy groups of the component (D) to cure the curable composition and is liquid at a temperature of 20° C. From the viewpoint of significantly achieving the effects of the present invention, the number of thiol groups in one molecule of the component (C) is preferably 2 or more (difunctional or more), more preferably 3 or more (trifunctional or more), and preferably 6 or less (hexafunctional or less), more preferably 5 or less (pentafunctional or less).

[0050] Examples of such liquid polythiol compounds include trimethylolpropane tris(3-mercaptopropionate) (abbreviation: TMTP), pentaerythritol tetrakis(3-mercaptopropionate) (abbreviation: PEMP), dipentaerythritol hexakis(3-mercaptopropionate) (abbreviation: DPMP), tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate (abbreviation: TEMPIC), tris(3-mercaptopropyl)isocyanurate (abbreviation: TMPIC), octyl thioglycolate (abbreviation: OTG), ethylene glycol bisthioglycolate (abbreviation: EGTG), trimethylolpropane tristhioglycolate (abbreviation: TMTG), pentaerythritol Examples of such esters include pentaerythritol tetrakis(2-mercaptoethyl)glycolate (abbreviated as PETG), 3-mercaptopropionic acid (abbreviated as 3-MPA), pentaerythritol tetrakis(3-mercaptobutyrate), 1,4-bis(3-mercaptobutyryloxy)butane, 1,3,5-tris(3-mercaptobutyryloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, trimethylolpropane tris(3-mercaptobutyrate) (abbreviated as TPMB), trimethylolethane tris(3-mercaptobutyrate) (abbreviated as TEMB), 1,3,4,6-tetrakis(2-mercaptoethyl)glycoluril, and 4,4'-isopropylidenebis[(3-mercaptopropoxy)benzene].

[0051] These compounds can be synthesized by known methods. For example, tris(3-mercaptopropyl)isocyanurate (abbreviation: TMPIC) and 4,4'-isopropylidenebis[(3-mercaptopropoxy)benzene] can be synthesized by the methods described in JP 2012-153794 A and WO 2001 / 00698 A.

[0052] Component (C) may be a commercially available product, such as "PEMP" (manufactured by SC Organic Chemical Industry Co., Ltd.), "OTG," "EGTG," "TMTG," "PETG," "3-MPA," "TMTP," "PETP" (manufactured by Yodo Chemical Co., Ltd.), "TEMP," "PEMP," "TEMPIC," "DPMP" (manufactured by Sakai Chemical Industry Co., Ltd.), "PE-1" (pentaerythritol tetrakis(3-mercaptobutyrate)), "BD-1" (1,4-bis(3-mercaptobutyryloxy)butane), "NR-1" (1,3,5-tris(3-mercaptobutyryloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione), "TPMB," "TEMB" (manufactured by Showa Denko K.K.), or "TS-G" (mercaptoethyl glycol) (manufactured by Shikoku Chemical Industry Co., Ltd.).

[0053] The thiol group equivalent of the polythiol compound is preferably 50 to 500 g / eq, more preferably 75 to 300 g / eq, and even more preferably 100 to 200 g / eq. The "thiol group equivalent" refers to the number of grams (g / eq) of a resin containing 1 gram equivalent of thiol groups, and can be measured by a known method, for example, iodine solution titration using starch as an indicator.

[0054] The ratio of the amounts of component (B) to component (C), expressed as the ratio of [total number of functional groups in component (B)] to [total number of thiol groups in component (C)], is preferably in the range of 1:0.1 to 1:5, more preferably 1:0.5 to 1:2, and even more preferably 1:0.5 to 1:1. Here, the functional group in (B) is any of a hydroxy group, a glycidyl group, an epoxy group, and a thiol group, represented by R in formula (B-1) above, and varies depending on the type of component (B). The total number of functional groups in component (B) is the sum of the solid mass of each component (B) divided by the functional group equivalent for all components (B), and the total number of thiol groups in component (C) is the sum of the solid mass of each component (C) divided by the thiol group equivalent for all components (C). By setting the ratio of component (B) to component (C) within this range, the effects of the present invention can be more significantly improved.

[0055] When the curable composition contains a (D) epoxy resin (described later), the ratio of the (D) epoxy resin to the (C) component, expressed as the ratio of [total number of epoxy groups in the epoxy resin] to [total number of thiol groups in the (C) component], is preferably in the range of 1:0.1 to 1:3, more preferably 1:0.5 to 1:2, and even more preferably 1:0.5 to 1:1. The total number of epoxy groups in the epoxy resins is the sum of the solid mass of each (D) epoxy resin divided by the epoxy equivalent weight, for all epoxy resins. The total number of thiol groups in the (C) component is the sum of the solid mass of each (C) component divided by the thiol group equivalent weight, for all (C) components. By maintaining the ratio of the (D) epoxy resin to the (C) component within this range, the heat resistance of the cured product of the curable composition is further improved.

[0056] From the viewpoints of improving the thermal conductivity of the cured product of the curable composition and reducing the elastic modulus, the content of component (C) is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, and is preferably 30% by mass or less, more preferably 28% by mass or less, and even more preferably 25% by mass or less, based on 100% by mass of the non-volatile components in the curable composition.

[0057] When the nonvolatile components in the curable composition are taken as 100% by mass, the content (% by mass) of component (B) is taken as B1, and the content (% by mass) of component (C) is taken as C1, from the viewpoint of significantly obtaining the effects of the present invention, B1 / C1 is preferably 0.1 or more, more preferably 0.8 or more, and even more preferably 1 or more, and is preferably 5 or less, more preferably 3 or less, and even more preferably 2 or less.

[0058] <(D) Epoxy resin> When the curable composition does not contain an epoxy group-containing silsesquioxane compound as component (B), the curable composition contains a (D) epoxy resin as component (D). When the curable composition contains an epoxy group-containing silsesquioxane compound as component (B), the curable composition may or may not contain a (D) epoxy resin as an optional component in combination with the above-mentioned components (A) to (C). This (D) epoxy resin does not include those corresponding to the above-mentioned components (A) to (C). Inclusion of component (D) in the curable composition can improve insulation reliability. When component (B) contains an epoxy group-containing silsesquioxane compound, the curable composition does not necessarily contain a (D) epoxy resin, but from the viewpoint of significantly achieving the effects of the present invention, it is preferable to contain a (D) epoxy resin.

[0059] Examples of component (D) include bisphenol A epoxy resins, bisphenol F epoxy resins, bisphenol S epoxy resins, bisphenol AF epoxy resins, dicyclopentadiene epoxy resins, trisphenol epoxy resins, naphthol novolac epoxy resins, phenol novolac epoxy resins, tert-butyl-catechol epoxy resins, naphthalene epoxy resins, naphthol epoxy resins, anthracene epoxy resins, glycidylamine epoxy resins, glycidyl ester epoxy resins, cresol novolac epoxy resins, biphenyl epoxy resins, linear aliphatic epoxy resins, epoxy resins having a butadiene structure, alicyclic epoxy resins, heterocyclic epoxy resins, spiro ring-containing epoxy resins, cyclohexanedimethanol epoxy resins, naphthylene ether epoxy resins, and trimethylol epoxy resins. The (D) epoxy resins may be used alone or in combination of two or more.

[0060] Component (D) preferably contains an epoxy resin having two or more epoxy groups per molecule. From the viewpoint of significantly achieving the desired effects of the present invention, the proportion of the epoxy resin having two or more epoxy groups per molecule is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass or more, relative to 100% by mass of the non-volatile components of the epoxy resin.

[0061] Component (D) is classified into epoxy resins that are liquid at a temperature of 20°C (hereinafter referred to as "liquid epoxy resins") and epoxy resins that are solid at a temperature of 20°C (hereinafter referred to as "solid epoxy resins"). The curable composition may contain, as epoxy resin (D), only a liquid epoxy resin, only a solid epoxy resin, or a combination of a liquid epoxy resin and a solid epoxy resin; however, from the viewpoint of significantly achieving the effects of the present invention, it is preferable to contain only a liquid epoxy resin.

[0062] The liquid epoxy resin is preferably a liquid epoxy resin having two or more epoxy groups in one molecule.

[0063] Preferred liquid epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AF type epoxy resins, naphthalene type epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, phenol novolac type epoxy resins, alicyclic epoxy resins having an ester skeleton, cyclohexane type epoxy resins, cyclohexanedimethanol type epoxy resins, glycidyl amine type epoxy resins, and epoxy resins having a butadiene structure, with bisphenol A type epoxy resins and bisphenol F type epoxy resins being more preferred.

[0064] Specific examples of liquid epoxy resins include "HP4032," "HP4032D," and "HP4032SS" (naphthalene-type epoxy resins) manufactured by DIC Corporation; "828US," "jER828EL," "825," and "Epikote 828EL" (bisphenol A-type epoxy resins) manufactured by Mitsubishi Chemical Corporation; "jER807" and "1750" (bisphenol F-type epoxy resins) manufactured by Mitsubishi Chemical Corporation; "jER152" (phenol novolac-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; and "630" and "630LSD" (glycidylamine-type epoxy resins) manufactured by Mitsubishi Chemical Corporation. ); "ZX1059" manufactured by Nippon Steel Chemical & Material Co., Ltd. (a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin); "EX-721" manufactured by Nagase ChemteX Corporation (a glycidyl ester type epoxy resin); "Celloxide 2021P" manufactured by Daicel Corporation (an alicyclic epoxy resin having an ester skeleton); "PB-3600" manufactured by Daicel Corporation (an epoxy resin having a butadiene structure); and "ZX1658" and "ZX1658GS" (liquid 1,4-glycidylcyclohexane type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd. These may be used alone or in combination of two or more.

[0065] As the solid epoxy resin, a solid epoxy resin having three or more epoxy groups in one molecule is preferred, and an aromatic solid epoxy resin having three or more epoxy groups in one molecule is more preferred.

[0066] Preferred solid epoxy resins include bixylenol-type epoxy resins, naphthalene-type epoxy resins, naphthalene-type tetrafunctional epoxy resins, novolac-type epoxy resins, cresol novolac-type epoxy resins, dicyclopentadiene-type epoxy resins, trisphenol-type epoxy resins, naphthol-type epoxy resins, biphenyl-type epoxy resins, naphthylene ether-type epoxy resins, anthracene-type epoxy resins, bisphenol A-type epoxy resins, bisphenol AF-type epoxy resins, and tetraphenylethane-type epoxy resins.

[0067] Specific examples of solid epoxy resins include "HP4032H" (naphthalene-type epoxy resin), "HP-4700", "HP-4710" (naphthalene-type tetrafunctional epoxy resin), "N-690" (cresol novolac-type epoxy resin), "N-695" (cresol novolac-type epoxy resin), "HP-7200", "HP-7200HH", "HP-7200H" (dicyclopentadiene-type epoxy resin), "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP6000", and "HP6000L" (naphthylene ether-type epoxy resin), manufactured by DIC Corporation; and "EPPN-502H" (trisphenol-type epoxy resin), "NC7000L" (naphthol novolac-type epoxy resin), "NC3000H", "NC3000", and "N" (N) ... Examples of epoxy resins include C3000L and NC3100 (biphenyl-type epoxy resins); Nippon Steel Chemical & Material Co., Ltd.'s ESN475V (naphthalene-type epoxy resin) and ESN485 (naphthol novolac-type epoxy resin); Mitsubishi Chemical Corporation's YX4000H, YL6121 (biphenyl-type epoxy resin), YX4000HK (bixylenol-type epoxy resin), YX8800 (anthracene-type epoxy resin), and 157S70 (novolac-type epoxy resin); Osaka Gas Chemicals Co., Ltd.'s PG-100 and CG-500, and Mitsubishi Chemical Corporation's YX7760 (bisphenol AF-type epoxy resin), YL7800 (fluorene-type epoxy resin), jER1010 (solid bisphenol A-type epoxy resin), and jER1031S (tetraphenylethane-type epoxy resin). These may be used alone or in combination of two or more.

[0068] When a combination of a solid epoxy resin and a liquid epoxy resin is used as the epoxy resin, the mass ratio thereof (solid epoxy resin:liquid epoxy resin) is preferably 1:0.01 to 1:50, more preferably 1:0.05 to 1:20, and particularly preferably 1:0.1 to 1:10. By setting the mass ratio of the liquid epoxy resin to the solid epoxy resin within this range, the following effects can be obtained: 1) when used in the form of a resin sheet, appropriate adhesiveness is imparted; 2) when used in the form of a resin sheet, sufficient flexibility is obtained and handling is improved; and 3) a cured product having sufficient breaking strength can be obtained.

[0069] The epoxy equivalent of the epoxy resin is preferably 50 g / eq to 5000 g / eq, more preferably 50 g / eq to 3000 g / eq, even more preferably 80 g / eq to 2000 g / eq, and even more preferably 110 g / eq to 1000 g / eq. By ensuring that the epoxy equivalent falls within this range, a cured product of the curable composition with sufficient crosslinking density can be obtained. The epoxy equivalent is the mass of an epoxy resin containing one equivalent of epoxy groups. This epoxy equivalent can be measured according to JIS K7236.

[0070] From the viewpoint of significantly achieving the desired effects of the present invention, the weight average molecular weight (Mw) of the epoxy resin is preferably 100 to 5000, more preferably 250 to 3000, and even more preferably 400 to 1500. The weight average molecular weight of the epoxy resin is a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

[0071] The content of the (D) epoxy resin is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, based on 100% by mass of the nonvolatile components in the curable composition, from the viewpoint of obtaining a cured product exhibiting good mechanical strength and insulating reliability. The upper limit of the content of the epoxy resin is preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less, from the viewpoint of significantly obtaining the desired effects of the present invention.

[0072] When the component (B) does not contain an epoxy group-containing silsesquioxane compound, the content of the epoxy resin (D), relative to 100 mass% of the non-volatile components in the curable composition, is preferably 1 mass% or more, more preferably 3 mass% or more, and even more preferably 5 mass% or more, and is preferably 25 mass% or less, more preferably 20 mass% or less, and even more preferably 15 mass% or less, from the viewpoint of significantly obtaining the effects of the present invention.

[0073] When the component (B) contains an epoxy group-containing silsesquioxane compound and the curable composition contains an epoxy resin (D), the content of the epoxy resin (D) is, from the viewpoint of significantly obtaining the effects of the present invention, preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, and is preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less, based on 100% by mass of the non-volatile components in the curable composition.

[0074] When the component (B) contains an epoxy group-containing silsesquioxane compound and also contains the component (D), when the content of the component (B) is B2 and the content of the component (D) is D1, assuming that the total amount of non-volatile components in the curable composition is 100 mass %, from the viewpoint of significantly obtaining the effects of the present invention, B2 / D1 is preferably 1 or more, more preferably 1.5 or more, even more preferably 2 or more, and is preferably 5 or less, more preferably 4 or less, even more preferably 3 or less.

[0075] When the component (B) does not contain an epoxy group-containing silsesquioxane compound but contains the component (D), when the content of the component (B) is B3 and the content of the component (D) is D1, assuming that the total amount of non-volatile components in the curable composition is 100 mass %, from the viewpoint of significantly obtaining the effects of the present invention, B3 / D1 is preferably 1 or more, more preferably 1.5 or more, and even more preferably 2 or more, and is preferably 5 or less, more preferably 4 or less, and even more preferably 3 or less.

[0076] <(E) Curing accelerator> The curable composition may further contain (E) a curing accelerator as an optional component in combination with the above-described components (A) to (D). The curing accelerator (E) as component (E) does not include those corresponding to the above-described components (A) to (D). The (E) curing accelerator functions as a curing catalyst that accelerates the curing of the (B) silsesquioxane compound and the (D) epoxy resin.

[0077] Examples of such (E) curing accelerators include phosphorus-based curing accelerators, urea-based curing accelerators, guanidine-based curing accelerators, imidazole-based curing accelerators, metal-based curing accelerators, amine-based curing accelerators, etc. One type of (E) curing accelerator may be used alone, or two or more types may be used in combination.

[0078] Examples of the phosphorus-based curing accelerator include aliphatic phosphonium salts such as tetrabutylphosphonium bromide, tetrabutylphosphonium chloride, tetrabutylphosphonium acetate, tetrabutylphosphonium decanoate, tetrabutylphosphonium laurate, bis(tetrabutylphosphonium)pyromellitate, tetrabutylphosphonium hydrogenhexahydrophthalate, tetrabutylphosphonium 2,6-bis[(2-hydroxy-5-methylphenyl)methyl]-4-methylphenolate, and di-tert-butyldimethylphosphonium tetraphenylborate; methyltriphenylphosphonium bromide, ethyltriphenylphosphonium bromide, propyltriphenylphosphonium bromide, butyltriphenylphosphonium bromide, benzyltriphenylphosphonium chloride, tetraphenylphosphonium bromide, p-tolyltriphenylphosphonium tetra-p-tolylborate, and tetraphenylphosphonium tetra-p-tolylborate. aromatic phosphonium salts such as tetraphenylborate, tetraphenylphosphonium tetra-p-tolylborate, triphenylethylphosphonium tetraphenylborate, tris(3-methylphenyl)ethylphosphonium tetraphenylborate, tris(2-methoxyphenyl)ethylphosphonium tetraphenylborate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, and butyltriphenylphosphonium thiocyanate; aromatic phosphine-borane complexes such as triphenylphosphine-triphenylborane; aromatic phosphine-quinone adducts such as triphenylphosphine-p-benzoquinone adduct; aliphatic phosphines such as tributylphosphine, tri-tert-butylphosphine, trioctylphosphine, di-tert-butyl(2-butenyl)phosphine, di-tert-butyl(3-methyl-2-butenyl)phosphine, and tricyclohexylphosphine;Dibutylphenylphosphine, di-tert-butylphenylphosphine, methyldiphenylphosphine, ethyldiphenylphosphine, butyldiphenylphosphine, diphenylcyclohexylphosphine, triphenylphosphine, tri-o-tolylphosphine, tri-m-tolylphosphine, tri-p-tolylphosphine, tris(4-ethylphenyl)phosphine, tris(4-propylphenyl)phosphine, tris(4-isopropylphenyl)phosphine, tris(4-butylphenyl)phosphine, tris(4-tert-butylphenyl)phosphine, tris(2,4-dimethylphenyl)phosphine, tris(2,5-dimethylphenyl)phosphine, tris(2,6-dimethylphenyl)phosphine aromatic phosphines such as benzene, tris(3,5-dimethylphenyl)phosphine, tris(2,4,6-trimethylphenyl)phosphine, tris(2,6-dimethyl-4-ethoxyphenyl)phosphine, tris(2-methoxyphenyl)phosphine, tris(4-methoxyphenyl)phosphine, tris(4-ethoxyphenyl)phosphine, tris(4-tert-butoxyphenyl)phosphine, diphenyl-2-pyridylphosphine, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 1,2-bis(diphenylphosphino)acetylene, and 2,2'-bis(diphenylphosphino)diphenyl ether;

[0079] Examples of the urea-based curing accelerator include 1,1-dimethylurea; aliphatic dimethylureas such as 1,1,3-trimethylurea, 3-ethyl-1,1-dimethylurea, 3-cyclohexyl-1,1-dimethylurea, and 3-cyclooctyl-1,1-dimethylurea; 3-phenyl-1,1-dimethylurea, 3-(4-chlorophenyl)-1,1-dimethylurea, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, 3-(3-chloro-4-methylphenyl)-1,1-dimethylurea, 3-(2-methylphenyl)-1,1-dimethylurea, 3-(4-methylphenyl)-1,1-dimethylurea, and 3-(3,4-dimethylphenyl)-1,1-dimethylurea. aromatic dimethylureas such as toluene bis(dimethylurea), 3-(4-isopropylphenyl)-1,1-dimethylurea, 3-(4-methoxyphenyl)-1,1-dimethylurea, 3-(4-nitrophenyl)-1,1-dimethylurea, 3-[4-(4-methoxyphenoxy)phenyl]-1,1-dimethylurea, 3-[4-(4-chlorophenoxy)phenyl]-1,1-dimethylurea, 3-[3-(trifluoromethyl)phenyl]-1,1-dimethylurea, N,N-(1,4-phenylene)bis(N',N'-dimethylurea), and N,N-(4-methyl-1,3-phenylene)bis(N',N'-dimethylurea) [toluene bisdimethylurea].

[0080] Examples of guanidine curing accelerators include dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 1-methylbiguanide, 1-ethylbiguanide, 1-n-butylbiguanide, 1-n-octadecylbiguanide, 1,1-dimethylbiguanide, 1,1-diethylbiguanide, 1-cyclohexylbiguanide, 1-allylbiguanide, 1-phenylbiguanide, and 1-(o-tolyl)biguanide.

[0081] Examples of the imidazole curing accelerator include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, and 1-benzyl-2-methylimidazole. Phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl -(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct Examples of imidazole compounds include 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, and 2-phenylimidazoline, as well as adducts of imidazole compounds with epoxy resins. Commercially available imidazole curing accelerators include "1B2PZ," "2E4MZ," "2MZA-PW," "2MZ-OK," "2MA-OK," "2MA-OK-PW," "2PHZ," "2PHZ-PW," "Cl1Z," "Cl1Z-CN," "Cl1Z-CNS," and "C11Z-A" manufactured by Shikoku Chemicals Corporation; and "P200-H50" manufactured by Mitsubishi Chemical Corporation.

[0082] Examples of metal-based curing accelerators include organometallic complexes or organometallic salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of organometallic complexes include organic cobalt complexes such as cobalt(II) acetylacetonate and cobalt(III) acetylacetonate, organic copper complexes such as copper(II) acetylacetonate, organic zinc complexes such as zinc(II) acetylacetonate, organic iron complexes such as iron(III) acetylacetonate, organic nickel complexes such as nickel(II) acetylacetonate, and organic manganese complexes such as manganese(II) acetylacetonate. Examples of organometallic salts include zinc octoate, tin octoate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

[0083] Examples of the amine curing accelerator include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, 1,8-diazabicyclo(5,4,0)-undecene, etc. Commercially available amine curing accelerators may be used, such as "MY-25" manufactured by Ajinomoto Fine-Techno Co., Inc.

[0084] The content of the (E) curing accelerator is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and even more preferably 0.5% by mass or more, and is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less, based on 100% by mass of the non-volatile components in the curable composition.

[0085] <(F) Optional Additives> The curable composition may further contain (F) an optional additive as an optional non-volatile component in addition to the above-mentioned components (A) to (D). (F) Optional additives include, for example, storage stabilizers; curing agents; thermoplastic resins; polymerization initiators; organometallic compounds such as organic copper compounds, organic zinc compounds, and organic cobalt compounds; colorants such as phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium oxide, and carbon black; polymerization inhibitors such as hydroquinone, catechol, pyrogallol, and phenothiazine; leveling agents such as silicone-based leveling agents and acrylic polymer-based leveling agents; thickeners such as bentone and montmorillonite; antifoaming agents such as silicone-based antifoaming agents, acrylic-based antifoaming agents, fluorine-based antifoaming agents, and vinyl resin-based antifoaming agents; ultraviolet absorbers such as benzotriazole-based ultraviolet absorbers; adhesion improvers such as urea silane; adhesion imparting agents such as triazole-based adhesion imparting agents, tetrazole-based adhesion imparting agents, and triazine-based adhesion imparting agents; hindered phenanthrene. surfactants such as fluorine-based surfactants and silicone-based surfactants; flame retardants such as phosphorus-based flame retardants (e.g., phosphate ester compounds, phosphazene compounds, phosphinic acid compounds, and red phosphorus), nitrogen-based flame retardants (e.g., melamine sulfate), halogen-based flame retardants, and inorganic flame retardants (e.g., antimony trioxide); dispersants such as phosphate ester-based dispersants, polyoxyalkylene-based dispersants, acetylene-based dispersants, silicone-based dispersants, anionic dispersants, and cationic dispersants; stabilizers such as borate-based stabilizers, titanate-based stabilizers, aluminate-based stabilizers, zirconate-based stabilizers, isocyanate-based stabilizers, carboxylic acid-based stabilizers, and carboxylic anhydride-based stabilizers; photopolymerization initiation aids such as tertiary amines; and photosensitizers such as pyrarizones, anthracenes, coumarins, xanthones, and thioxanthones. (F) The optional additives may be used alone or in combination of two or more.

[0086] The curable composition may further contain any solvent as a volatile component. Examples of the solvent include organic solvents. The solvent may be used alone or in combination of two or more in any ratio.

[0087] Examples of the solvent include ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester-based solvents such as methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, isoamyl acetate, methyl propionate, ethyl propionate, and γ-butyrolactone; ether-based solvents such as tetrahydropyran, tetrahydrofuran, 1,4-dioxane, diethyl ether, diisopropyl ether, dibutyl ether, and diphenyl ether; alcohol-based solvents such as methanol, ethanol, propanol, butanol, and ethylene glycol; and 2-ethoxyethyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl diglycol acetate, γ-butyrolactone, and methyl methoxypropionate. Examples of suitable solvents include ether ester solvents; ester alcohol solvents such as methyl lactate, ethyl lactate, and methyl 2-hydroxyisobutyrate; ether alcohol solvents such as 2-methoxypropanol, 2-methoxyethanol, 2-ethoxyethanol, propylene glycol monomethyl ether, and diethylene glycol monobutyl ether (butyl carbitol); amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; sulfoxide solvents such as dimethyl sulfoxide; nitrile solvents such as acetonitrile and propionitrile; aliphatic hydrocarbon solvents such as hexane, cyclopentane, cyclohexane, and methylcyclohexane; and aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, and trimethylbenzene.

[0088] The amount of solvent is preferably 3% by mass or less, more preferably 1% by mass or less, even more preferably 0.5% by mass or less, even more preferably 0.1% by mass or less, and even more preferably 0.01% by mass or less, relative to 100% by mass of non-volatile components in the curable composition. It is particularly preferable that the curable composition be free of solvent (0% by mass). When the amount of solvent is thus small, the curable composition may be in a paste form. The viscosity of the paste-like curable composition at 25°C is preferably in the range of 20 Pa·s to 1000 Pa·s.

[0089] The method for preparing the curable composition is not particularly limited. For example, the composition can be produced by adding the ingredients to a preparation vessel in any order and / or simultaneously, partially or entirely, and mixing them. The temperature can be appropriately set during the process of adding and mixing each ingredient, and heating and / or cooling can be performed temporarily or throughout the process. Stirring or shaking can be performed during the process of adding and mixing each ingredient. The curable composition can be stirred or shaken using a stirring or shaking device such as a mixer during or after the addition and mixing to achieve uniform dispersion. Simultaneously with the stirring or shaking, degassing can be performed under low-pressure conditions, such as under vacuum. The mixing temperature can be, for example, 10 to 40°C. The stirring speed during mixing can be, for example, 100 to 10,000 rpm. The mixing time can be, for example, 10 seconds to 10 minutes.

[0090] <Physical properties and uses of curable compositions> The cured product obtained by thermally curing the curable composition at 120°C for 90 minutes exhibits excellent thermal conductivity. This results in an insulating layer with high thermal conductivity. The thermal conductivity is preferably 1.4 W / m·K or higher, more preferably 1.41 W / m·K or higher, and even more preferably 1.42 W / m·K or higher. The upper limit of the thermal conductivity is not particularly limited, but may be 10 W / m·K or lower. The thermal conductivity can be measured according to the method described in the Examples below.

[0091] The cured product obtained by thermally curing the curable composition at 120°C for 90 minutes exhibits a low modulus of elasticity. That is, an insulating layer exhibiting a low modulus of elasticity is obtained. The modulus of elasticity of the cured product is preferably less than 4000 MPa, more preferably 3500 MPa or less, and even more preferably 1000 MPa or less, 600 MPa or less, 500 MPa or less, or 150 MPa or less. The lower limit is not particularly limited, but may be 0.1 MPa or more. The modulus of elasticity can be measured according to the method described in the Examples below. Because the cured product exhibits a low modulus of elasticity, a cured product with excellent impact resistance can be obtained.

[0092] The curable composition of the present invention can provide an insulating layer with high thermal conductivity and low elastic modulus. Therefore, the curable composition of the present invention can be suitably used as a curable composition for bonding a heat sink to an electronic component (curable composition for heat sink adhesion), a curable composition for forming an insulating layer of a semiconductor chip package (curable composition for insulating layer of semiconductor chip package), or a curable composition for forming an insulating layer of a circuit board (including a printed wiring board) (curable composition for insulating layer of circuit board). It can also be suitably used as a curable composition for forming an interlayer insulating layer on which a conductor layer is formed by plating (curable composition for interlayer insulating layer of circuit board on which a conductor layer is formed by plating). It can also be suitably used as a curable composition for encapsulating a semiconductor chip (curable composition for semiconductor chip encapsulation) or a curable composition for forming wiring on a semiconductor chip (curable composition for forming semiconductor chip wiring).

[0093] [Curable composition-containing sheet] The curable composition-containing sheet of the present invention includes a support and a curable composition layer formed from the curable composition of the present invention and provided on the support.

[0094] From the viewpoint of thinning, the thickness of the curable composition layer is preferably 200 μm or less, more preferably 150 μm or less, and even more preferably 100 μm or less. The lower limit of the thickness of the curable composition layer is not particularly limited, but can usually be 1 μm or more, 5 μm or more, 10 μm or more, etc.

[0095] Examples of the support include films made of plastic materials, metal foils, and release papers, with films made of plastic materials and metal foils being preferred.

[0096] When a film made of a plastic material is used as the support, examples of the plastic material include polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate (hereinafter sometimes abbreviated as "PEN"), polycarbonate (hereinafter sometimes abbreviated as "PC"), acrylics such as polymethyl methacrylate (PMMA), cyclic polyolefins, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, polyimide, etc. Among these, polyethylene terephthalate and polyethylene naphthalate are preferred, with inexpensive polyethylene terephthalate being particularly preferred.

[0097] When a metal foil is used as the support, examples of the metal foil include copper foil and aluminum foil, with copper foil being preferred. The copper foil may be a foil made of a single metal, copper, or an alloy of copper and another metal (e.g., tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.).

[0098] The surface of the support that is to be bonded to the curable composition layer may be subjected to a matte treatment, a corona treatment, or an antistatic treatment.

[0099] The support may also be a support with a release layer, which has a release layer on the surface that bonds to the curable composition layer. Examples of the release agent used in the release layer of the support with a release layer include one or more release agents selected from the group consisting of alkyd resins, polyolefin resins, urethane resins, and silicone resins. Commercially available products may also be used as the support with a release layer, including, for example, "SK-1," "AL-5," and "AL-7" manufactured by Lintec Corporation, "Lumirror T60" manufactured by Toray Industries, Inc., "Purex" manufactured by Teijin Limited, and "Uni-Peel" manufactured by Unitika Limited, which are PET films having a release layer primarily composed of an alkyd resin-based release agent.

[0100] The thickness of the support is not particularly limited, but is preferably in the range of 5 μm to 75 μm, more preferably 10 μm to 60 μm. When a support with a release layer is used, it is preferable that the thickness of the entire support with a release layer is in the above range.

[0101] In one embodiment, the curable composition-containing sheet may further include other layers as necessary. Examples of such other layers include a protective film conforming to the support and provided on the surface of the curable composition layer not bonded to the support (i.e., the surface opposite the support). The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. By laminating the protective film, adhesion of dust and the like to the surface of the curable composition layer and scratches can be suppressed.

[0102] The curable composition-containing sheet can be produced, for example, by preparing a curable composition-containing varnish by dissolving the curable composition in an organic solvent, applying this curable composition-containing varnish onto a support using a die coater or the like, and then drying it to form a curable composition layer.

[0103] The organic solvent is the same as the solvent that may be contained in the curable composition, as described above.

[0104] Drying may be carried out by known methods such as heating or hot air blowing. Drying conditions are not particularly limited, but drying is carried out so that the content of organic solvent in the curable composition layer becomes 10% by mass or less, preferably 5% by mass or less. Although it varies depending on the boiling point of the organic solvent in the curable composition-containing varnish, for example, when a curable composition-containing varnish containing 30% by mass to 60% by mass of organic solvent is used, the curable composition layer can be formed by drying at 50°C to 150°C for 3 to 10 minutes.

[0105] The curable composition-containing sheet can be stored by being wound up in a roll. When the curable composition-containing sheet has a protective film, it can be used by peeling off the protective film.

[0106] [Circuit board] The circuit board of the present invention includes an insulating layer formed from a cured product of the curable composition of the present invention. The method for manufacturing a circuit board of the present invention comprises the steps of: (1) a step of preparing a substrate with a wiring layer, the substrate having a substrate and a wiring layer provided on at least one surface of the substrate; (2) forming a curable composition layer on the substrate with the wiring layer so that the wiring layer is embedded, and thermally curing the composition to form an insulating layer; (3) A process for connecting wiring layers to each other is included. The method for manufacturing a circuit board may also include (4) the step of removing the base material.

[0107] Step (3) is not particularly limited as long as it can connect the wiring layers to each other, but it is preferably at least one of the steps of forming a via hole in an insulating layer to form a wiring layer, and polishing or grinding the insulating layer to expose the wiring layer.

[0108] <Process (1)> Step (1) is a step of preparing a substrate with a wiring layer, which has a substrate and a wiring layer provided on at least one surface of the substrate. Typically, a substrate with a wiring layer has a first metal layer and a second metal layer, which are part of the substrate, on both sides of the substrate, and a wiring layer on the surface of the second metal layer opposite the substrate-side surface. Specifically, a dry film (photosensitive resist film) is laminated on the substrate, and a patterned dry film is formed by exposing and developing the film under specified conditions using a photomask. The developed patterned dry film is used as a plating mask to form a wiring layer by electroplating, and then the patterned dry film is peeled off.

[0109] Examples of the substrate include glass epoxy substrates, metal substrates (such as stainless steel and cold-rolled steel sheet (SPCC)), polyester substrates, polyimide substrates, BT resin substrates, and thermosetting polyphenylene ether substrates, and the substrate surface may have a metal layer such as copper foil formed thereon. Furthermore, a peelable metal layer such as a first metal layer and a second metal layer (for example, an ultra-thin copper foil with a carrier foil manufactured by Mitsui Mining & Smelting Co., Ltd., product name "Micro Thin") may be formed thereon.

[0110] The dry film is not particularly limited as long as it is a photosensitive dry film made of a photoresist composition, and examples thereof include dry films of novolac resin, acrylic resin, etc. Commercially available dry films may also be used.

[0111] The substrate and the dry film may be laminated by a vacuum lamination method. In the vacuum lamination method, the thermocompression temperature is preferably in the range of 60°C to 160°C, more preferably 80°C to 140°C, the thermocompression pressure is preferably in the range of 0.098MPa to 1.77MPa, more preferably 0.29MPa to 1.47MPa, and the thermocompression time is preferably in the range of 20 seconds to 400 seconds, more preferably 30 seconds to 300 seconds. The lamination is preferably carried out under reduced pressure conditions of 13 hPa or less.

[0112] After laminating the dry film on the substrate, the dry film is exposed to light and developed under predetermined conditions using a photomask to form a desired pattern.

[0113] The line (circuit width) / space (width between circuits) ratio of the wiring layer is not particularly limited, but is preferably 20 / 20 μm or less (i.e., a pitch of 40 μm or less), more preferably 10 / 10 μm or less, even more preferably 5 / 5 μm or less, even more preferably 1 / 1 μm or less, and particularly preferably 0.5 / 0.5 μm or more. The pitch does not need to be uniform throughout the wiring layer. The minimum pitch of the wiring layer may be 40 μm or less, 36 μm or less, or 30 μm or less.

[0114] After forming the pattern of the dry film, a wiring layer is formed and the dry film is peeled off. Here, the wiring layer can be formed by a plating method using the dry film with the desired pattern formed as a plating mask.

[0115] The conductive material used for the wiring layer is not particularly limited. In a preferred embodiment, the wiring layer contains one or more metals selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium. The wiring layer may be a single metal layer or an alloy layer. Examples of alloy layers include those formed from an alloy of two or more metals selected from the above group (e.g., nickel-chromium alloy, copper-nickel alloy, and copper-titanium alloy). Among these, from the viewpoints of versatility in wiring layer formation, cost, ease of patterning, etc., single metal layers of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or alloy layers of nickel-chromium alloy, copper-nickel alloy, or copper-titanium alloy are preferred. Single metal layers of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or alloy layers of nickel-chromium alloy are more preferred, and single metal layers of copper are even more preferred.

[0116] The thickness of the wiring layer depends on the desired design of the wiring board, but is preferably 3 μm to 35 μm, more preferably 5 μm to 30 μm, and even more preferably 10 to 20 μm or 15 to 20 μm. When the step (3) involves polishing or grinding the insulating layer to expose the wiring layer and connect the wiring layers to each other, it is preferable that the thickness of the wiring that connects the layers be different from that of the wiring that does not connect the layers. The thickness of the wiring layer can be adjusted by repeating the above-mentioned pattern formation. The thickness of the thickest wiring layer (conductive pillar) among the wiring layers depends on the desired design of the wiring board, but is preferably 2 μm or more and 100 μm or less. The wiring that connects the layers to each other may be convex.

[0117] After the wiring layer is formed, the dry film is peeled off. The dry film can be peeled off using, for example, an alkaline peeling solution such as a sodium hydroxide solution. If necessary, unnecessary wiring patterns can be removed by etching or the like to form a desired wiring pattern. The pitch of the wiring layer to be formed is as described above.

[0118] <Process (2)> Step (2) is a step of forming a curable composition layer on the substrate with a wiring layer so that the wiring layer is embedded, and then thermally curing the curable composition layer to form an insulating layer. In detail, a curable composition layer of a curable composition-containing sheet is bonded to the wiring layer of the substrate with a wiring layer obtained in the above-mentioned step (1), and the curable composition layer is thermally cured to form an insulating layer. Alternatively, step (2) may involve applying a curable composition to the substrate with a wiring layer, and then thermally curing the curable composition to form an insulating layer.

[0119] In one embodiment of the method for forming the curable composition layer, a curable composition-containing sheet is laminated on a substrate with a wiring layer so that the curable composition layer is bonded to the substrate with a wiring layer. In one embodiment, lamination of the substrate with a wiring layer and the curable composition-containing sheet can be performed, for example, by thermocompression bonding the curable composition-containing sheet to the substrate with a wiring layer from the support side. Examples of a member for thermocompression bonding the curable composition-containing sheet to the substrate with a wiring layer (hereinafter also referred to as a "thermocompression bonding member") include a heated metal plate (such as a SUS panel) or a metal roll (SUS roll). Note that it is preferable to press the curable composition-containing sheet with the thermocompression bonding member not directly against the substrate with a wiring layer, but via an elastic material such as heat-resistant rubber so that the curable composition-containing sheet can sufficiently conform to the surface irregularities of the substrate with a wiring layer.

[0120] The wiring layer-bearing substrate and the curable composition-containing sheet may be laminated by vacuum lamination. In vacuum lamination, the thermocompression temperature is preferably 60°C to 160°C, more preferably 80°C to 140°C, the thermocompression pressure is preferably 0.098MPa to 1.77MPa, more preferably 0.29MPa to 1.47MPa, and the thermocompression time is preferably 10 seconds to 400 seconds, more preferably 20 seconds to 300 seconds. Furthermore, the lamination is preferably carried out under reduced pressure conditions of 26.7 hPa or less.

[0121] The lamination can be performed using a commercially available vacuum laminator, such as a vacuum pressure laminator manufactured by Meiki Seisakusho Co., Ltd., a vacuum applicator manufactured by Nikko Materials Co., Ltd., or a batch vacuum pressure laminator.

[0122] After lamination, the laminated curable composition-containing sheet may be smoothed under normal pressure (atmospheric pressure), for example, by pressing the support side with a thermocompression member. The pressing conditions for the smoothing treatment may be the same as the thermocompression conditions for lamination. The smoothing treatment may be performed using a commercially available laminator. Note that lamination and smoothing treatment may be performed consecutively using the commercially available vacuum laminator.

[0123] In another embodiment of the method for forming the curable composition layer, the curable composition is applied to the substrate having the wiring layer by, for example, injecting the curable composition with a syringe and pressing the curable composition to form a curable composition layer of uniform thickness.

[0124] A curable composition layer is formed on the substrate with the wiring layer so that the wiring layer is embedded, and then the curable composition layer is thermally cured to form an insulating layer. The thermal curing conditions for the curable composition layer vary depending on the type of curable composition, but for example, the curing temperature can be in the range of 120°C to 240°C, and the curing time can be in the range of 5 minutes to 120 minutes. Before thermally curing the curable composition layer, the curable composition layer may be preheated at a temperature lower than the curing temperature.

[0125] After the curable composition layer is thermally cured to form an insulating layer, the surface of the insulating layer may be polished. The polishing method is not particularly limited, and the surface of the insulating layer may be polished by a known method, for example, using a surface grinder.

[0126] <Process (3)> Step (3) is a step of connecting the wiring layers to each other. Specifically, it is a step of forming a via hole in an insulating layer and forming a conductor layer to connect the wiring layers to each other. Alternatively, it is a step of polishing or grinding the insulating layer to expose the wiring layer to connect the wiring layers to each other.

[0127] When a process of forming a via hole in an insulating layer and forming a conductor layer to connect wiring layers to each other is adopted, the formation of the via hole is not particularly limited, and examples thereof include laser irradiation, etching, mechanical drilling, etc., but laser irradiation is preferred. This laser irradiation can be performed using any suitable laser processing machine that uses a carbon dioxide laser, YAG laser, excimer laser, etc. as a light source.

[0128] The conditions for laser irradiation are not particularly limited, and laser irradiation can be carried out by any suitable process according to a conventional method depending on the selected means.

[0129] The shape of the via hole, that is, the shape of the outline of the opening when viewed in the extending direction, is not particularly limited, but is generally circular (approximately circular).

[0130] After the via holes are formed, a so-called desmearing process, which is a process for removing smears from the via holes, may be performed. When the conductive layer described below is formed by a plating process, the via holes may be subjected to, for example, a wet desmearing process, and when the conductive layer is formed by a sputtering process, a dry desmearing process such as a plasma treatment process may be performed. The desmearing process may also serve as a roughening treatment process.

[0131] Before forming the conductor layer, the via hole and the insulating layer may be subjected to a roughening treatment. The roughening treatment may be performed using a known procedure and conditions that are usually used. An example of a dry roughening treatment is a plasma treatment, and an example of a wet roughening treatment is a method in which a swelling treatment with a swelling liquid, a roughening treatment with an oxidizing agent, and a neutralization treatment with a neutralizing liquid are performed in this order.

[0132] The surface roughness (Ra) of the insulating layer surface after roughening treatment is preferably 350 nm or more, more preferably 400 nm or more, and even more preferably 450 nm or more. The upper limit is preferably 700 nm or less, more preferably 650 nm or less, and even more preferably 600 nm or less. The surface roughness (Ra) can be measured, for example, using a non-contact surface roughness meter.

[0133] After the via holes are formed, a conductor layer is formed. The conductor material constituting the conductor layer is not particularly limited, and the conductor layer can be formed by any suitable conventional method such as plating, sputtering, or vapor deposition, and is preferably formed by plating. In a preferred embodiment, for example, a conductor layer having a desired wiring pattern can be formed by plating the surface of the insulating layer using a conventional technique such as a semi-additive method or a full-additive method. The conductor layer may have a single-layer structure or a multi-layer structure in which two or more single metal layers or alloy layers made of different types of metals or alloys are laminated.

[0134] In detail, a plating seed layer is formed on the surface of the insulating layer by electroless plating. Next, a mask pattern is formed on the formed plating seed layer, exposing a portion of the plating seed layer corresponding to the desired wiring pattern. An electrolytic plating layer is formed on the exposed plating seed layer by electrolytic plating. At this time, via holes may be filled by electrolytic plating along with the formation of the electrolytic plating layer to form filled vias. After the electrolytic plating layer is formed, the mask pattern is removed. Thereafter, unnecessary plating seed layer is removed by etching or the like, thereby forming a conductor layer having the desired wiring pattern. Note that when forming the conductor layer, the dry film used to form the mask pattern is the same as the dry film described above.

[0135] The conductor layer may include not only linear wiring but also, for example, electrode pads (lands) on which external terminals can be mounted, etc. The conductor layer may also be composed of electrode pads only.

[0136] Alternatively, the conductor layer may be formed by forming an electrolytic plating layer and a filled via without using a mask pattern after forming a plating seed layer, and then patterning by etching.

[0137] When a process of polishing or grinding an insulating layer to expose a wiring layer and connect the wiring layers to each other is adopted, the method of polishing or grinding the insulating layer is not particularly limited as long as it can expose the wiring layer and the polished or ground surface is horizontal. Conventional polishing or grinding methods can be applied, such as chemical mechanical polishing using a chemical mechanical polishing device, mechanical polishing using a buff, or surface grinding using a rotating grinding wheel. As with the process of forming via holes in an insulating layer and forming a conductor layer to connect the wiring layers to each other, a smear removal process and a roughening process may be performed, and a conductor layer may be formed. Furthermore, it is not necessary to expose the entire wiring layer; only a portion of the wiring layer may be exposed.

[0138] <Process (4)> Step (4) is a step of removing the substrate to form the circuit board of the present invention. The method for removing the substrate is not particularly limited. In a preferred embodiment, the substrate is peeled from the circuit board at the interface between the first and second metal layers, and the second metal layer is etched away with, for example, a copper chloride aqueous solution. If necessary, the substrate may be peeled off while the conductor layer is protected with a protective film.

[0139] [Semiconductor chip package] The semiconductor chip package of the present invention comprises a cured product of the curable composition of the present invention.

[0140] In one embodiment, the semiconductor chip package of the present invention is a semiconductor chip package in which a semiconductor chip is mounted on the circuit board. The semiconductor chip package can be manufactured by bonding the semiconductor chip to the circuit board.

[0141] The bonding conditions are not particularly limited as long as the terminal electrodes of the semiconductor chip are conductively connected to the circuit wiring of the circuit board, and known conditions used in flip-chip mounting of semiconductor chips may be used. Alternatively, the semiconductor chip and the circuit board may be bonded via an insulating adhesive.

[0142] In a preferred embodiment, the semiconductor chip is pressure-bonded to the circuit board under pressure conditions such as a pressure-bonding temperature in the range of 120°C to 240°C (preferably 130°C to 200°C, more preferably 140°C to 180°C) and a pressure-bonding time in the range of 1 second to 60 seconds (preferably 5 seconds to 30 seconds).

[0143] In another preferred embodiment, the semiconductor chip is bonded to the circuit board by reflow. The reflow conditions can be, for example, in the range of 120°C to 300°C.

[0144] After bonding the semiconductor chip to the circuit board, for example, the semiconductor chip can be filled with a molded underfill material to obtain a semiconductor chip package. The method of filling with the molded underfill material can be carried out by a known method. The molded underfill material may be a curable composition.

[0145] In another embodiment (hereinafter also referred to as "second embodiment"), the semiconductor chip package of the present invention can be produced, for example, by a method including the following steps (A) to (F) using the curable composition of the present invention. The curable composition of the present invention can be used to form the encapsulating layer in step (C) or the rewiring formation layer in step (E). An example of forming an encapsulating layer or a rewiring formation layer using a curable composition is shown below, but techniques for forming encapsulating layers and rewiring formation layers for semiconductor chip packages are known, and a person skilled in the art can produce a semiconductor chip package using the curable composition of the present invention according to known techniques. (A) a step of laminating a temporary fixing film on a substrate; (B) a step of temporarily fixing a semiconductor chip on a temporary fixing film; (C) forming an encapsulation layer on the semiconductor chip; (D) peeling the substrate and the temporary fixing film from the semiconductor chip; (E) forming a rewiring formation layer as an insulating layer on the surface of the semiconductor chip from which the base material and the temporary fixing film have been peeled off; and (F) A step of forming a rewiring layer as a conductor layer on the rewiring formation layer.

[0146] <Process (A)> The material used for the substrate is not particularly limited. Examples of the substrate include a silicon wafer, a glass wafer, a glass substrate, a metal substrate such as copper, titanium, stainless steel, or cold-rolled steel sheet (SPCC), a substrate made of glass fiber impregnated with epoxy resin or the like and subjected to a thermosetting treatment (e.g., an FR-4 substrate), and a substrate made of bismaleimide triazine resin (BT resin).

[0147] The material of the temporary fixing film is not particularly limited as long as it can be peeled off from the semiconductor chip in step (D) and can temporarily fix the semiconductor chip. Commercially available products can be used as the temporary fixing film. Examples of commercially available products include Riva Alpha manufactured by Nitto Denko Corporation.

[0148] <Process (B)> The semiconductor chip is temporarily fixed on the temporary fixing film so that its electrode pad surface is bonded to the temporary fixing film. The temporary fixing of the semiconductor chip can be performed using a known device such as a flip chip bonder or a die bonder. The layout and number of semiconductor chips to be arranged can be appropriately set depending on the shape and size of the temporary fixing film, the number of semiconductor packages to be produced, etc., and for example, the semiconductor chips can be temporarily fixed by arranging them in a matrix of multiple rows and multiple columns.

[0149] <Process (C)> The curable composition of the present invention is applied to a semiconductor chip and cured (for example, thermally cured) to form an encapsulating layer. Alternatively, the curable composition of the present invention may be laminated on a semiconductor chip in the form of the curable composition-containing sheet and cured (for example, thermally cured) to form an encapsulating layer.

[0150] When the curable composition-containing sheet is used in the form of a curable composition-containing sheet, the semiconductor chip and the curable composition-containing sheet can be laminated by removing the protective film of the curable composition-containing sheet as necessary, and then heat-pressing the curable composition-containing sheet to the semiconductor chip from the support side. The semiconductor chip and the curable composition-containing sheet can be laminated by a vacuum lamination method, and the lamination conditions are the same as those in step (2) of the method for producing a circuit board.

[0151] After lamination, the curable composition is thermally cured to form the sealing layer under the same conditions as those in step (2) of the method for producing a circuit board.

[0152] The support of the curable composition-containing sheet may be peeled off after the curable composition-containing sheet is laminated on the semiconductor chip and thermally cured, or the support may be peeled off before the curable composition-containing sheet is laminated on the semiconductor chip.

[0153] When the sealing layer is formed by applying the curable composition of the present invention, the application conditions are the same as the application conditions when the curable composition layer in the curable composition-containing sheet of the present invention is formed.

[0154] <Process (D)> The method for peeling off the substrate and the temporary fixing film can be changed as appropriate depending on the material of the temporary fixing film, etc., and examples include a method in which the temporary fixing film is heated and foamed (or expanded) to peel it off, and a method in which ultraviolet light is irradiated from the substrate side to reduce the adhesive strength of the temporary fixing film and peel it off.

[0155] In the method of heating and foaming (or expanding) the temporary fixing film to peel it off, the heating conditions are usually 100 to 250°C for 1 to 90 seconds or 5 to 15 minutes. In the method of irradiating ultraviolet light from the substrate side to reduce the adhesive strength of the temporary fixing film to peel it off, the irradiation dose of ultraviolet light is usually 10 mJ / cm. 2 ~1000mJ / cm 2 is.

[0156] <Process (E)> The material for forming the rewiring formation layer (insulating layer) is not particularly limited as long as it has insulating properties when the rewiring formation layer (insulating layer) is formed, and from the viewpoint of ease of manufacturing a semiconductor chip package, a photosensitive resin or a thermosetting resin is preferred. The rewiring formation layer may be formed using the curable composition of the present invention.

[0157] After forming the redistribution layer, via holes may be formed in the redistribution layer to connect the semiconductor chip to a conductor layer (described later). The via holes may be formed by a known method depending on the material of the redistribution layer.

[0158] <Process (F)> The material of the conductor layer formed on the rewiring formation layer is not particularly limited. In a preferred embodiment, the conductor layer is made of the same conductor material as that used for the wiring layer of the circuit board. The conductor material is as described above.

[0159] The conductor layer may have a single layer structure or a multi-layer structure in which two or more single metal layers or alloy layers made of different types of metals or alloys are laminated. When the conductor layer has a multi-layer structure, the layer in contact with the insulating layer is preferably a single metal layer of chromium, zinc, or titanium, or an alloy layer of a nickel-chromium alloy.

[0160] The thickness of the conductor layer depends on the desired design of the semiconductor chip package, but is generally 1 μm to 35 μm, preferably 1 μm to 20 μm.

[0161] In one embodiment, the conductor layer may be formed by plating. For example, a conductor layer having a desired wiring pattern can be formed by plating the surface of the rewiring formation layer using a conventionally known technique such as a semi-additive method or a full-additive method. From the viewpoint of ease of production, it is preferable to form the conductor layer by a semi-additive method. An example of forming the conductor layer by a semi-additive method will be described below.

[0162] First, a plating seed layer is formed on the surface of the rewiring formation layer by electroless plating. Next, a mask pattern is formed on the formed plating seed layer, exposing a portion of the plating seed layer corresponding to the desired wiring pattern. After a metal layer is formed on the exposed plating seed layer by electrolytic plating, the mask pattern is removed. Thereafter, unnecessary plating seed layer is removed by etching or the like, thereby forming a conductor layer (rewiring layer) having the desired wiring pattern.

[0163] The steps (E) and (F) may be repeated to alternately stack (build up) conductive layers (rewiring layers) and rewiring formation layers (insulating layers).

[0164] The manufacturing of the semiconductor chip package may further include the steps of (G) forming a solder resist layer on the conductor layer (rewiring layer), (H) forming bumps, and (I) dicing the plurality of semiconductor chip packages into individual semiconductor chip packages. These steps may be performed according to various methods known to those skilled in the art for use in manufacturing semiconductor chip packages.

[0165] The second embodiment is a method of first providing a semiconductor chip and then forming a rewiring layer on the electrode pad surface, i.e., a chip 1st (Chip-1 st In addition to the chip 1st process, the semiconductor chip package of the present invention can also be manufactured by a process in which a rewiring layer is first provided, and then a semiconductor chip is provided on the rewiring layer in a state in which the electrode pad surface can be electrically connected to the rewiring layer, and then the semiconductor chip is sealed. This is called the rewiring layer 1st (RDL-1) process. st ) method may also be used.

[0166] The semiconductor chip package of the present invention can be a fan-in package or a fan-out package by forming a sealing layer, a rewiring formation layer, etc. using the curable composition of the present invention. The curable composition of the present invention can be applied to both a fan-out panel level package (FOPLP) and a fan-out wafer level package (FOWLP).

[0167] [Semiconductor Devices] Semiconductor devices that can be equipped with the semiconductor chip package of the present invention include various semiconductor devices used in electrical appliances (e.g., computers, mobile phones, smartphones, tablet devices, wearable devices, digital cameras, camera modules, medical equipment, and televisions) and vehicles (e.g., motorcycles, automobiles, trains, ships, and aircraft).

[0168] [Electronic materials] The electronic member of the present invention comprises an electronic component, a cured product of the curable composition of the present invention disposed on the electronic component, and a heat dissipation member attached to the cured product. The cured product of the curable composition has high thermal conductivity and low elasticity. For example, by disposing the cured product of the curable composition on the electronic component so as to adhere it to the electronic component and then attaching the heat dissipation member to the cured product, the heat dissipation efficiency of the electronic component to the heat dissipation member can be improved. The cured product can be formed by a method similar to that of step (2) described above. The electronic component of the present invention may comprise multiple heat dissipation members. In this case, the electronic component preferably comprises an electronic component, a first cured product of the curable composition of the present invention disposed on the electronic component, a first heat dissipation member attached to the first cured product, a second cured product of the curable composition of the present invention disposed on the heat dissipation member, and a second heat dissipation member attached to the second cured product. The first cured product and the second cured product may be the same or different components. Furthermore, the first heat dissipation member and the second heat dissipation member may be the same heat dissipation member, or may be different heat dissipation members.

[0169] Examples of heat dissipation members include heat spreaders and heat sinks. Examples of electronic components include semiconductor chip packages, power semiconductors, and LED-PKGs. Examples of electronic members include circuit boards, semiconductor chip packages, and semiconductor devices. [Example]

[0170] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the following description, "parts" and "%" representing amounts mean "parts by mass" and "% by mass", respectively, unless otherwise specified.

[0171] [Preparation of Curable Composition] The components were mixed according to the formulation shown in the table below to prepare curable compositions according to Examples 1 to 7 and Comparative Examples 1 to 3. Specifically, the amounts (parts by mass) shown in the table below were weighed out and placed in dedicated plastic containers. Then, using a planetary centrifugal vacuum mixer, Awatori Rentaro (ARE-310, manufactured by Thinky Corporation), the components were thoroughly mixed at 2000 rpm at room temperature and further degassed for 1 minute to obtain curable compositions. In the table, the amount of each component is indicated in parts by mass.

[0172] [Table 1]

[0173] The abbreviations in the table are as follows: Component (A) PT-110A: MOMENTIVE boron nitride filler (average particle size 33 μm) (B) Component SQ-502-8: Arakawa Chemical Industries, Ltd., epoxy-containing silsesquioxane compound (contains 16.5% isopropyl alcohol and 3.5% toluene), epoxy equivalent weight approximately 276g / eq. SQ-107: Arakawa Chemical Industries, Ltd., thiol-containing silsesquioxane compound (contains 24.4% ethylene glycol dimethyl ether and 4% toluene), thiol equivalent weight approximately 206g / eq. (C) Component TMTP: Yodo Chemical Co., Ltd., trimethylolpropane tristhiopropionate, thiol equivalent 140g / eq. PEMP: SC Organic Chemicals, Pentaerythritol tetrakis(3-mercaptopropionate), thiol equivalent weight 122g / eq. PE-1: Showa Denko Co., Ltd., pentaerythritol tetrakis(3-mercaptobutyrate), thiol equivalent 135g / eq. (D) Component ZX1059: Manufactured by Nippon Steel Corporation, bisphenol epoxy resin (a 1:1 mixture of bisphenol A and bisphenol F), epoxy equivalent weight approximately 165g / eq. (E) Component 1B2PZ: Shikoku Chemical Industry Co., Ltd., 1-benzyl-2-phenylimidazole (F) Component HN-2200 (acid anhydride curing agent): Showa Denko Materials Co., Ltd., 3 or 4-methyl-1,2,3,6-tetrahydrophthalic anhydride, molecular weight 166, acid anhydride equivalent weight 179 g / eq.

[0174] [Measurement and evaluation of thermal conductivity] Each curable composition was placed in a designated container and thermally cured in a heat circulation oven at 120°C for 90 minutes to produce cylindrical cured products measuring 10 mm thick and 36 mm in diameter. The thermal conductivity of the resulting cylindrical cured products was measured using the hot disk method at a constant temperature of 25°C and 40% RH using a Kyoto Electronics Manufacturing Co., Ltd. "TPS-2500" tester. The measured thermal conductivity was evaluated according to the following criteria. 〇: Thermal conductivity is 1.40W / mK or more ×: Thermal conductivity is less than 1.40 W / mK

[0175] [Measurement and evaluation of elastic modulus] Each curable composition was applied to a release PET film (NS-80A, manufactured by Toray Industries, Inc.) using a bar coater and then heat-cured at 120°C for 90 minutes to obtain a cured product. The resulting cured product, 100 μm thick, was punched out with a dumbbell (trade name "Super Dumbbell Cutter (Model: SDMK-5889-01)", manufactured by Dumbbell Co., Ltd.) to prepare a test piece for measuring tensile strength. The PET film was peeled off from the test piece. A tensile test was performed using a Tensilon universal testing machine (manufactured by Orientec Co., Ltd., RTM-500) under conditions of a temperature of 25°C, humidity of 60%, and a pulling rate of 50 mm / min. The measured elastic modulus was evaluated according to the following criteria. ○: Elastic modulus less than 4000 MPa ×: Elastic modulus is 4000 MPa or more

[0176] [Table 2]

Claims

[Claim 1] (A) a thermally conductive filler; (B) a silsesquioxane compound, and (C) A curable composition containing a liquid polythiol compound, When the component (B) does not contain an epoxy group-containing silsesquioxane compound having an epoxy group, the curable composition further contains an epoxy resin (D), When the component (B) contains an epoxy group-containing silsesquioxane compound, the curable composition may contain or not contain an epoxy resin (D).

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