Curable composition, cured product, and method for producing the same

Abstract

To provide: a curable composition from which, when turned into a cured product, the cured product having, excellent adhesive property and moist heat resistance even after cooling and heating cycles, and excellent bending strength is obtained; the cured product; and its production method.SOLUTION: A curable composition for melt molding which exhibits thermosetting property includes: a polyamide resin (A) having a dimer structure derived at least from either a dimer acid or a dimer diamine; an epoxy resin (B); and at least one of silica filler (C) and thermally conductive filler (D), wherein a total input rate of the dimer acid and the dimer diamine is set to be 50-100 mass% based on 100 mass% of total monomers used for polymerization of the polyamide resin (A), the epoxy resin (B) satisfies at least one of softening point of 50-120°C and melting point of 70-120°C, and 0.1 mass% or more and less than 0.6 mass% of the polyamide resin (A) is compounded based on 100 mass% of non-volatile components.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a curable composition containing a polyamide resin, an epoxy resin, and at least one of a silica filler and a thermally conductive filler, and also to a cured product obtained by molding and curing the curable composition by thermal melting, and a method for producing the same. [Background technology]

[0002] Integrated circuits (ICs) are essential components of electronic components, such as microprocessors, transistors, and memory, and are installed in various electronic devices such as computers, smartphones, and flat panel displays. Packages containing ICs or mounting boards on which ICs are mounted use insulating resins such as encapsulants, adhesives, underfill agents, and potting materials.

[0003] Patent Document 1 discloses a resin composition as a mold underfill material for WL-CSP (wafer level chip size package), which contains a polymer resin having a number average molecular weight within a specific range and one or more structures selected from a polybutadiene structure, a polyisoprene structure, a polycarbonate structure, a (meth)acrylate structure, and a polysiloxane structure, an inorganic filler, an epoxy resin, and a curing accelerator. Furthermore, Patent Document 2 proposes a sealing film containing one or more elastomers selected from the group consisting of butadiene-based rubbers and silicone-based rubbers, an epoxy resin, a curing agent, and an inorganic filler, and containing a specific amount of the elastomer component. Furthermore, Patent Document 3 discloses a radically polymerizable polyamide, which is a reaction product of a polyamide having a dimer structure consisting of a dimer acid or dimer diamine and a phenolic hydroxyl group unit, and a hydroxyl group in a side chain, with a radically polymerizable epoxy. It also discloses a resin composition containing this radically polymerizable polyamide, a photopolymerization initiator, an epoxy resin, a phenolic resin, a silica filler, a solvent, etc. Furthermore, Patent Document 4 discloses a thermosetting resin composition containing a polyamide having a dimer structure obtained by polymerizing a polybasic acid monomer and a polyamine monomer and having phenolic hydroxyl groups in its side chains, and a tri- or higher functional compound capable of reacting with the phenolic hydroxyl groups. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2017-057313 [Patent Document 2] International Publication No. 2016 / 136741 [Patent Document 3] Japanese Patent Application Publication No. 2019-119886 [Patent Document 4] International Publication No. 2016 / 001949 Summary of the Invention [Problem to be solved by the invention]

[0005] The manufacturing process for semiconductor packages involves multiple heating steps to form the redistribution layer. For example, fan-out wafer-level packaging (FO-WLP) has attracted attention as a chip-sized package that allows for increased pin counts. The manufacturing process for face-down WLPs, a typical example of FO-WLP, involves encapsulating a semiconductor chip on one side with a molding resin composition, followed by repeated heating steps to form the redistribution layer. Therefore, there is a demand for resin compositions with high humidity and heat resistance that can suppress foaming and cracking during heating.

[0006] Because electronic components and devices are widely used in automobiles, industrial machinery, ships, aircraft, etc., there is a market demand for resin compositions that are highly reliable even under harsh conditions and have excellent thermal cycling properties. Improved thermal cycling properties are particularly desired for encapsulants for power IC packages, which are expected to become more widespread. Furthermore, in response to the trend toward lighter, thinner, and smaller electronic components, electronic components such as IC packages are also required to be thinner, and there is a demand for resin compositions that can produce cured products with high bending strength.

[0007] The present invention has been made in view of the above-mentioned background, and an object of the present invention is to provide a curable composition that can give a cured product that has excellent adhesion and moist heat resistance even after a thermal cycling test and also has excellent flexural strength, a cured product, and a method for producing the same. [Means for solving the problem]

[0008] As a result of extensive research, the present inventors have found that the problems of the present invention can be solved by the following aspects, and have thus completed the present invention. [1]: A curable composition for melt molding that exhibits thermosetting properties, The composition comprises a polyamide resin (A) having a dimer structure derived from at least one of a dimer acid and a dimer diamine, an epoxy resin (B), and at least one of a silica filler (C) and a thermally conductive filler (D), the total amount of the dimer acid and the dimer diamine is 50 to 100% by mass relative to 100% by mass of all the monomers used in the polymerization of the polyamide resin (A), The epoxy resin (B) has a softening point of 50 to 120°C and a melting point of 70 to 120°C. A curable composition comprising a polyamide resin (A) in an amount of 0.1% by mass or more and less than 0.6% by mass based on 100% by mass of the nonvolatile content. [2]: The curable composition according to [1], wherein the polyamide resin (A) has a glass transition temperature of 0 to 90°C. [3]: The curable composition according to claim 1 or 2, wherein the total amount of the silica filler (C) and the thermally conductive filler (D) (including the case where only one of the silica filler (C) and the thermally conductive filler (D) is present) is 40% by mass or more relative to 100% by mass of the nonvolatile content. [4]: The curable composition according to any one of [1] to [3], wherein the polyamide resin (A) has a weight average molecular weight of 15,000 to 100,000. [5]: The curable composition according to any one of [1] to [4], further comprising a compound (E) which is at least one selected from the group consisting of an acid anhydride group-containing compound, an isocyanate compound, an aziridine compound, an amine compound, a phenol compound, and a metal chelate. [6]: The curable composition according to any one of [1] to [5], further comprising a liquid epoxy compound (F). [7]: The curable composition according to any one of [1] to [6], wherein at least one of the silica filler (C) and the thermally conductive filler (D) contains two or more types. [8] The curable composition according to any one of [1] to [7], which is in the form of a sheet, powder, granules, or tablet. [9]: The curable composition according to any one of [1] to [8], which is a solvent-free type.

[10] : A cured product obtained by molding the curable composition according to any one of [1] to [9] by thermal melting and curing it.

[11] : The cured product according to

[10] , which has a glass transition temperature of 100 to 200°C.

[12] : A polyamide resin (A) having a dimer structure derived from at least one of a dimer acid and a dimer diamine, an epoxy resin (B), and at least one of a silica filler (C) and a thermally conductive filler (D), Polyamide resin (A) is blended in an amount of 0.1% by mass or more and less than 0.6% by mass relative to 100% by mass of nonvolatile content, the total content of the dimer acid and the dimer diamine is 50 to 100% by mass based on 100% by mass of all monomers constituting the polyamide resin (A), The epoxy resin (B) has a softening point of 50 to 120°C and a melting point of 70 to 120°C, A method for producing a cured product, comprising the steps of: molding a curable composition exhibiting thermosetting properties by thermal melting; and thermally curing the composition.

[13] : The method for producing a cured product according to

[12] , wherein the curable composition is a solventless type. [Effects of the Invention]

[0009] The present invention has the excellent effect of providing a curable composition that can give a cured product that has excellent adhesion and moist heat resistance even after a thermal cycling test and also has excellent flexural strength, a cured product, and a method for producing the same. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be described in detail below. Needless to say, other embodiments are also included within the scope of the present invention as long as they are consistent with the spirit of the present invention. Furthermore, in this specification, a numerical range specified using "to" includes the numerical values ​​before and after "to" as the lower and upper limit ranges. Furthermore, in this specification, "film" and "sheet" are not distinguished by thickness. In other words, in this specification, "sheet" includes thin film-like materials, and in this specification, "film" includes thick sheet-like materials. Furthermore, unless otherwise noted, the various components mentioned in this specification may be used independently, either singly or in combination of two or more types.

[0011] In this specification, "Mw" refers to the weight average molecular weight in terms of polystyrene determined by gel permeation chromatography (GPC). Mw can be measured by the method described in the Examples section.

[0012] The curable composition according to the present embodiment is a thermosetting melt-molding composition. It comprises a polyamide resin (A) (hereinafter simply referred to as "polyamide resin (A)") having a dimer structure derived from at least one of a dimer acid and a dimer diamine; an epoxy resin (B) (hereinafter simply referred to as "epoxy resin (B)") having a softening point of 50 to 120°C and a melting point of 70 to 120°C; and at least one of a silica filler (C) and a thermally conductive filler (D). The polyamide resin (A) contains the dimer acid and the dimer diamine in a total amount of 50 to 100% by mass of the total monomers used in the polymerization of the polyamide resin (A). The ratio of the monomers used in the polymerization of the polyamide resin (A) is essentially the ratio of the constituent components derived from the monomers of the polyamide resin (A). The polyamide resin (A) is blended in an amount of 0.1% by mass or more relative to 100% by mass of the nonvolatile content.

[0013] As used herein, "melt molding" refers to flowing a curable composition in a molten state to form a molded product of a different shape. The components of the curable composition may be partially crosslinked (semi-cured) at the stage of the curable composition. The curable composition may contain a solvent or may be solvent-free. A solvent is a low-molecular-weight compound that is liquid at room temperature and normal pressure and can be removed by heating or reducing pressure. It is used to dissolve or disperse the components constituting the curable composition. Examples of solvents include organic low-molecular-weight compounds such as toluene, ethyl acetate, and ethyl methyl ketone. The term "solvent-free" as used herein refers to a composition in which the solvent is 2% by mass or less of 100% by mass of the curable composition. When using a solvent-free composition, solvents used during synthesis of the components of the curable composition or during preparation of the composition may remain, but it is preferable that they have been removed as much as possible, and it is more preferable that the composition is substantially solvent-free (contains no solvent other than unavoidably contained solvents). The solvent content is expressed as a percentage of the mass of the solvent contained relative to the mass of the curable composition before drying under reduced pressure, assuming that the difference in mass of the curable composition before drying under reduced pressure at room temperature is the mass of the solvent contained.

[0014] Furthermore, the "molded product of a different shape" does not include a simple change in size or a slight deformation to the extent of covering the irregularities on the surface of the object to be joined, while maintaining the original shape macroscopically. For example, if the curable composition is a sheet, this does not include a case where the thickness is simply reduced by heat pressing, or a case where wiring or the like having a thickness less than the thickness of the sheet is covered with the sheet.

[0015] The present curable composition contains a specific amount of polyamide resin (A) having a dimer structure derived from at least one of dimer acid and dimer diamine, and further contains an epoxy resin (B) and at least one of a silica filler (C) and a thermally conductive filler (D). The following effects are obtained in a cured product obtained by melt molding and curing. Specifically, when the cured product is used as a sealing resin for IC packages, for example, it can improve moisture and heat resistance. It also exhibits excellent adhesion to semiconductor chips, metals, and the like. It also provides a cured product that has excellent adhesion and moisture and heat resistance, even after a thermal cycling test, and also has excellent flexural strength. As a result, it provides a cured product with excellent foaming and crack resistance. These effects are explained in more detail below.

[0016] [[Curable composition]] [Polyamide resin (A)] Polyamide resins are polymers containing repeating structural units containing amide groups. Among these, polyamide resins (A) are those having a dimer structure derived from at least one of dimer acid and dimer diamine. Polyamide resin (A) is a polymer of a polybasic acid compound, a polyamine compound, and optionally other monomers, or a modified product of such a polymer. Here, the term "modified product" refers to a derivative obtained by modifying a portion of the molecular structure of the polymer (e.g., by modifying a functional group, substituting with another compound, or adding another compound). The dimer structure can be introduced into the polyamide resin by using a monomer having a dimer structure, and the preferred monomers are dimer acid, which is a polybasic acid compound, and / or dimer diamine, which is a polyamine compound.

[0017] The polyamide resin (A) is blended in an amount of 0.1% by mass or more, based on 100% by mass of the nonvolatile content of the curable composition. This amount is more preferably 0.15% by mass or more, and even more preferably 0.2% by mass or more. Blending 0.1% by mass or more of polyamide resin (A) with epoxy resin (B), based on 100% by mass of the nonvolatile content, can provide a curable composition that provides a cured product with excellent adhesion and moist heat resistance even after a thermal cycling test, and excellent flexural strength. The upper limit of the polyamide resin (A) content can be set to 30% by mass, based on the Tg of the cured product. From the perspective of improving adhesion and moist heat resistance after a thermal cycling test by adding polyamide resin (A) while leveraging the excellent properties of the epoxy resin (B) itself, a low content of polyamide resin (A) is preferred, for example, less than 0.6% by mass, based on 100% by mass of the nonvolatile content of the curable composition.

[0018] The total content of dimer acid and dimer diamine in 100% by mass of all monomers used in the polymerization of polyamide resin (A) is 50 to 100% by mass. The content ratio of the monomers used in the polymerization of polyamide resin (A) is substantially the same as the proportion of the constituent components derived from the monomers of polyamide resin (A). That is, the proportion of the constituent units of the dimer structure derived from dimer acid and dimer diamine in polyamide resin (A) is substantially 50 to 100% by mass. By setting the content ratio to 50 to 100% by mass, the effect of the dimer structure can be fully exhibited. The total content of dimer acid and dimer diamine is preferably 60 to 95% by mass, more preferably 70 to 90% by mass. In the case of a polymer, the content of the dimer structure can be determined from the content (% by mass) of raw material monomers having a dimer structure in a total of 100% by mass of all raw material monomers used in synthesizing the polyamide resin (A). In the case of a modified product, the content can be determined from the content (% by mass) of raw material monomers having a dimer structure in 100% by mass of all monomers, using a hypothetical monomer having the structure after modification as the raw material monomer for an unmodified monomer. The content of the hypothetical monomer having the structure after modification can be determined taking into account the reactivity with respect to the polymer. For example, when modifying a side group derived from monomer a after obtaining a polymer, the content of the dimer structure of other monomers can be determined in the same manner as for the polymer described above, using the monomer amount (mass) X calculated by "charge amount of monomer a (mol) × side group modification rate / 100 × molecular weight of a hypothetical monomer having the structure after the side group has been modified" and the monomer amount (mass) Y calculated by "charge amount of monomer a (mol) × (1 - side group modification rate / 100) × molecular weight of monomer a".

[0019] The dimer structure has a hydrocarbon chain or ring structure and has a lower polarity than the epoxy resins to be blended, so that moisture absorption from outside the system can be suppressed. By solidifying the polyamide resin (A) through a melting process, the polyamide resin (A) and the epoxy resin (B) are easily phase-separated at the micron level, forming a microphase-separated structure. The dimer structure of the polyamide resin (A) provides flexibility, while the hydrogen bonds derived from the amide bonds of the polyamide resin (A) and the portion of the polyamide resin (A) that is compatible with the epoxy resin (B) provide restraints. Adding such a polyamide resin (A) to the hard epoxy resin (B) is believed to enhance the thermal cycling and flexural strength of the cured product of this curable composition. The flexibility provided by the dimer structure of the polyamide resin (A), along with the strong hydrogen bonds derived from the amide bonds and the portion of the polyamide resin (A) that is compatible with the epoxy resin (B), is believed to enhance flexural strength, effectively suppress deterioration in adhesive strength and hygrothermal resistance after repeated high-temperature and low-temperature cycles, and inhibit foaming and cracking of the cured product. By solidifying the polyamide resin (A) through a melting process, the effects of adding the polyamide resin (A) are more effectively enhanced.

[0020] The polyamide resin (A) preferably has a functional group capable of thermally crosslinking with the epoxy group of the epoxy resin (B). Examples of the functional group include a carboxy group, an amino group, and a hydroxyl group. These functional groups may be derived from the monomer of the polyamide resin (A), or may be introduced as a modified product after the polymer is obtained. The functional group may be present at the terminal of the polymer, or may be present in a side group and / or a side chain. A preferred example is a polymer having a functional group such as a carboxy group or an amino group at the terminal. Another example is a polymer having at least one of a carboxy group, an amino group, a hydroxyl group, or a side group in a side group or a side chain. Incidentally, if the curable composition contains a photopolymerizable group as a functional group, the curable composition containing the polyamide resin may be over-crosslinked, resulting in a decrease in adhesiveness, or when the curable composition is thermally melted and molded, a thermal radical reaction may occur, resulting in a decrease in moldability. Therefore, it is preferable that the curable composition does not contain a photopolymerizable group.

[0021] When the polyamide resin (A) has a hydroxyl group, a phenolic hydroxyl group is preferred. The presence of a phenolic hydroxyl group allows for the establishment of a crosslinked structure with the epoxy resin (B), resulting in a cured product with excellent durability. The phenolic hydroxyl group can be easily introduced by using a polybasic acid compound having a phenolic hydroxyl group and / or a polyamine compound having a phenolic hydroxyl group. The aromatic ring of this phenolic hydroxyl group is preferably contained in the main chain skeleton of the polyamide resin (A). From the viewpoint of durability, it is also preferred to use a polybasic acid compound having a phenolic hydroxyl group as a monomer for the polyamide resin (A).

[0022] The polyamide resin (A) may be a polyamideimide having imide groups in part thereof, or a polyamideester having ester groups in part thereof, within the scope of the present invention.

[0023] <Polybasic acid compounds> The polybasic acid compound is a dibasic or higher carboxylic acid. A part of the polybasic acid compound may be an acid anhydride. Examples of the polybasic acid compound include dimer acids and polybasic acid compounds other than dimer acids.

[0024] When a dimer acid is used as the polybasic acid compound, the content of the dimer acid in 100% by mass of the polybasic acid compound is preferably 60% by mass or more and 100% by mass or less, and more preferably 80% by mass or more. When the content of the dimer acid in 100% by mass of the polybasic acid compound is 60% by mass or more, the moist heat resistance is improved, the stress relaxation effect of the dimer structure is fully exerted, and better adhesive strength can be exerted.

[0025] (dimer acid) Dimer acid is a polybasic acid compound having a dimer structure, and is a dimer of a fatty acid (hereinafter referred to as a fatty acid dimer).

[0026] The fatty acid dimer is preferably a compound having 20 to 60 carbon atoms, more preferably a compound having 24 to 56 carbon atoms, even more preferably a compound having 28 to 48 carbon atoms, and particularly preferably a compound having 36 to 44 carbon atoms. The fatty acid dimer is preferably a dicarboxylic acid compound having a branched structure obtained by subjecting a fatty acid to a Diels-Alder reaction. The branched structure preferably includes an aliphatic chain or an aliphatic chain and a cyclic structure, and more preferably includes an aliphatic chain and a cyclic structure. The cyclic structure is preferably one or more aromatic rings or an alicyclic structure, and more preferably an alicyclic structure. The alicyclic structure may have one double bond within the ring, or may have no double bond.

[0027] Examples of polybasic acid compounds having a dimer structure include structures represented by the following chemical formulas (1) to (4): It goes without saying that the polybasic acid compounds having a dimer structure are not limited to the following structures.

[0028] [ka] [ka] [ka] [ka]

[0029] The fatty acid is preferably an unsaturated fatty acid having 10 to 30 carbon atoms, more preferably an unsaturated fatty acid having 10 to 24 carbon atoms. The unsaturated fatty acid has one or more carbon-carbon double bonds or carbon-carbon triple bonds. Examples of the fatty acid include natural fatty acids such as soybean oil fatty acid, tall oil fatty acid, and rapeseed oil fatty acid, as well as oleic acid, linoleic acid, linolenic acid, and erucic acid, which are obtained by refining these fatty acids. When synthesizing the fatty acid dimer, in addition to the fatty acid dimer, a fatty acid trimer and sometimes a tetramer are also produced. Therefore, a polybasic acid compound containing a dimer skeleton is a mixture containing not only the fatty acid dimer as the main component but also the fatty acid trimer and the like, and in some cases the fatty acid as the raw material. The fatty acid dimer preferably accounts for 70% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, of 100% by mass of the dimer acid.

[0030] Dimer acids may contain residual unsaturated bonds because unsaturated fatty acids are used as raw materials. In such cases, hydrogenation (also known as a hydrogenation reaction) can be performed to reduce the number of unsaturated bonds. This improves the reaction stability during synthesis of polyamide resin (A) and also improves the high-temperature resistance of the cured product of the curable composition containing polyamide resin (A). Dimer acids can be used alone or in combination of two or more types.

[0031] Commercially available dimer acids include, for example, "Pripol 1004," "Pripol 1006," "Pripol 1009," "Pripol 1013," "Pripol 1015," "Pripol 1017," "Pripol 1022," "Pripol 1025," and "Pripol 1040" manufactured by Croda Japan; and "Empol 1008," "Empol 1012," "Empol 1016," "Empol 1026," "Empol 1028," "Empol 1043," "Empol 1061," and "Empol 1062" manufactured by BASF Japan. Among these, the use of "Pripol 1009," which has 36 carbon atoms, makes it easier to obtain a polyamide resin (A) that exhibits excellent thermal cycling properties while maintaining adhesion to metals. Furthermore, the use of "Pripol 1004," which has 44 carbon atoms, makes it easier to obtain a polyamide resin (A) that exhibits excellent flexibility.

[0032] (Other polybasic acid compounds) The other polybasic acid compounds are polybasic acid compounds other than dimer acids, and are bifunctional or higher functional compounds. The polybasic acid compounds can be used alone or in combination of two or more kinds.

[0033] Examples of dibasic acid compounds include aromatic dibasic acids such as phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, benzophenone-4,4'-dicarboxylic acid, and 4,4'-biphenyldicarboxylic acid; aliphatic dibasic acids such as oxalic acid, malonic acid, methylmalonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, malic acid, tartaric acid, thiomalic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, hexadecanedioic acid, and diglycolic acid; and alicyclic dibasic acids such as 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and 1,3-cyclopentanedicarboxylic acid. Among these, isophthalic acid and 1,4-cyclohexanedicarboxylic acid are preferred as dibasic acid compounds.

[0034] Examples of trifunctional or higher functional polybasic acid compounds include trimellitic acid, hydrogenated trimellitic acid, pyromellitic acid, hydrogenated pyromellitic acid, trimesic acid, and 1,4,5,8-naphthalenetetracarboxylic acid. The use of trifunctional or higher functional polybasic acid compounds allows for the introduction of a branched structure into the polyamide resin (A), thereby improving the cohesive strength of the cured product and improving its thermal cycling resistance and dimensional stability.

[0035] Other suitable examples of polybasic acid compounds include polybasic acid compounds having a phenolic hydroxyl group. The polybasic acid compound having a phenolic hydroxyl group is a compound that has a hydroxyl group (also called a phenolic hydroxyl group) directly bonded to an aromatic ring, similar to phenol, and has two or more acidic functional groups. Examples of the acidic functional group include a carboxyl group. By using a polybasic acid compound having a phenolic hydroxyl group, it is possible to easily adjust the crosslinking structure between the polyamide resin (A) and the epoxy resin (B) during the curing treatment, which results in the formation of strong crosslinks, effectively improving the durability of the cured product.

[0036] Examples of polybasic acid compounds having a phenolic hydroxyl group include monohydroxyisophthalic acids such as 2-hydroxyisophthalic acid, 4-hydroxyisophthalic acid, and 5-hydroxyisophthalic acid; dihydroxyisophthalic acids such as 2,5-dihydroxyisophthalic acid, 2,4-dihydroxyisophthalic acid, and 4,6-dihydroxyisophthalic acid; monohydroxyterephthalic acids such as 2-hydroxyterephthalic acid; dihydroxyterephthalic acids such as 2,3-dihydroxyterephthalic acid and 2,6-dihydroxyterephthalic acid; hydroxyphthalic acids such as 3-hydroxyphthalic acid and 4-hydroxyphthalic acid; and dihydroxyphthalic acids such as 3,4-dihydroxyphthalic acid, 3,5-dihydroxyphthalic acid, 4,5-dihydroxyphthalic acid, and 3,6-dihydroxyphthalic acid. Among these, 5-hydroxyisophthalic acid is preferred as the polybasic acid compound having a phenolic hydroxyl group in terms of copolymerizability, ease of availability, etc. In the polybasic acid compound having a phenolic hydroxyl group, the carboxy group of the compound exemplified above may form an acid anhydride group, or the carboxy group may form an ester.

[0037] <Polyamine compounds> The polyamine compound is a compound having two or more amino groups. Suitable examples of the polyamine compound include dimer diamine and other polyamine compounds. When dimer diamine is used as the polyamine compound, the content of dimer diamine in 100% by mass of the polyamine compound is preferably 50% by mass or more and 100% by mass or less, and more preferably 90% by mass or more. By making the content of dimer diamine in 100% by mass of the polyamine compound 50% by mass or more, the stress relaxation property due to the dimer structure can be fully exhibited, and better thermal cycle resistance can be achieved.

[0038] (Dimer diamine) Dimer diamines are compounds with two amino groups in a dimer structure, and can be compounds obtained by converting the carboxyl groups of the dimer acids described above into amino groups. Examples of the conversion method include amidating a carboxylic acid, converting it to an amine by Hofmann rearrangement, and then distilling and purifying the product. The dimer diamine is preferably a compound having 20 to 60 carbon atoms, more preferably a compound having 24 to 56 carbon atoms, even more preferably a compound having 28 to 48 carbon atoms, and from the viewpoint of availability, even more preferably a compound having 36 to 44 carbon atoms.

[0039] Commercially available dimer diamines include, for example, "Priamine 1071," "Priamine 1073," "Priamine 1074," and "Priamine 1075" manufactured by Croda Japan, and "Versamine 551" manufactured by BASF Japan. The dimer diamines can be used alone or in combination of two or more.

[0040] (Other polyamine compounds) The other polyamine compounds are polyamine compounds other than dimer diamine, and examples thereof include diamine compounds and tri- or higher functional polyamine compounds.

[0041] Examples of the diamine compound include 1,4-diaminobenzene, 1,3-diaminobenzene, 1,2-diaminobenzene, 1,5-diaminonaphthalene, 1,8-diaminonaphthalene, 2,3-diaminonaphthalene, 2,6-diaminotoluene, 2,4-diaminotoluene, 3,4-diaminotoluene, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 4,4'-diamino-1,2-diphenylethane, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminobenzophenone, and 4,4'-diaminodiphenyl Examples of the diamine include aromatic diamines such as phenyl sulfone, 3,3'-diaminobenzophenone, and 3,3'-diaminodiphenyl sulfone; aliphatic diamines such as ethylene diamine, 1,3-propane diamine, 1,4-butane diamine, 1,6-hexane diamine, 1,7-heptane diamine, 1,9-nonane diamine, 1,12-dodecamethylene diamine, and meta-xylene diamine; and alicyclic diamines such as isophorone diamine, norbornane diamine, 1,2-cyclohexane diamine, 1,3-cyclohexane diamine, 1,4-cyclohexane diamine, 4,4'-diaminodicyclohexylmethane, and piperazine.

[0042] Further, polyamine compounds having phenolic hydroxyl groups can be used. Polyamide resins (A) using polyamine compounds having phenolic hydroxyl groups are preferred in terms of durability. The use of polyamine compounds having phenolic hydroxyl groups is preferred because phenolic hydroxyl groups can be introduced into the polyamide resin (A). The introduction of phenolic hydroxyl groups allows three-dimensional crosslinking with the epoxy resin (B) to be blended, making it possible to obtain a tougher cured product. The polyamine compound having a phenolic hydroxyl group has a plurality of amino groups and a phenolic hydroxyl group, and examples of the polyamine compound having a phenolic hydroxyl group include polyamines represented by the following general formula (1):

[0043] [ka]

[0044] R in the formula 1 represents a direct bond or a group containing carbon, hydrogen, oxygen, nitrogen, sulfur, or halogen. Examples of the group include a divalent hydrocarbon group having 1 to 30 carbon atoms, a divalent hydrocarbon group having 1 to 30 carbon atoms in which some or all of the hydrogen atoms have been substituted with halogen atoms, -(C=O)-, -SO2-, -O-, -S-, -NH-(C=O)-, -(C=O)-O-, a group represented by the following general formula (2), and a group represented by the following general formula (3).

[0045] [ka]

[0046] [ka] In the formula, r and s each independently represent an integer of 1 to 20; 2 represents a hydrogen atom or a methyl group.

[0047] Examples of polyamines represented by general formula (1) include 2,2-bis(3-amino-4-hydroxyphenyl)propane, 9,9-bis(3-amino-4-hydroxyphenyl)fluorene, and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane 4,4'-diamino-3,3'-dihydroxybisphenyl.

[0048] Examples of amines having three or more amino groups and no phenolic hydroxyl group include 1,2,4-triaminobenzene and 3,4,4'-triaminodiphenyl ether.

[0049] Among these, isophoronediamine or norbornanediamine is preferred as the other polyamine compound in terms of increasing the resistance to moist heat and further improving the adhesive strength and thermal cycling resistance.

[0050] <Method for producing polyamide resin (A)> The polyamide resin (A) can be synthesized by, for example, melt polymerization, interfacial polymerization, solution polymerization, bulk polymerization, solid-state polymerization, or a combination of these. Among these, solution polymerization is preferred. The polyamide resin (A) can be polymerized using the polybasic acid compound, polyamine compound, and, if necessary, other monomers, in the presence or absence of a catalyst. For example, a nitrogen-filled flask is charged with a predetermined amount of dimer acid, other acid monomers, dimer diamine, other amine-based monomers, and ion-exchanged water, and the mixture is stirred at 20 to 100°C to achieve a uniform solution or dispersion. The temperature is then gradually increased to 230°C while removing the ion-exchanged water and water generated by the reaction. Upon reaching 230°C, the pressure is reduced to approximately 15 mmHg and maintained at this pressure for approximately 1 hour to obtain polyamide resin (A). The heating temperature after reduced pressure is, for example, 150 to 300°C, and the heating time can be approximately 1 to 24 hours. To accelerate the synthesis reaction, a dehydration or dealcoholization reaction is preferably performed. To avoid coloration and decomposition due to high temperatures, the reaction is preferably performed under reduced pressure at 180 to 270°C.

[0051] As other monomers, monoamines may be used in combination with polyamines. Monoamines act as reaction terminators, making it easy to adjust the molecular weight of the polyamide resin (A). In addition, since some of the main chain terminals of the polyamide resin (A) are not reactive functional groups, the stability over time is improved. Examples of monoamines include aniline, benzylamine, 4-aminophenol, and 2-ethylhexylamine.

[0052] <Physical properties of polyamide resin (A)> The glass transition temperature (Tg) of the polyamide resin (A) is preferably 0 to 90° C., more preferably 10 to 70° C., and even more preferably 20 to 60° C. Tg is the temperature at which the value (tan δ) obtained by dividing the viscosity term by the elasticity term measured for the polyamide resin (A) using a dynamic viscoelasticity measuring device shows a maximum. By setting the Tg of the polyamide resin (A) to 0°C or higher, blocking between sheets can be effectively suppressed when the curable composition is molded into a sheet, for example, and handling can be improved. Furthermore, by setting the Tg of the polyamide resin (A) to 90°C or lower, compatibility with the epoxy resin (B), silica filler (C), and thermally conductive filler (D) can be further improved in the step of forming a melt of the curable composition, making it easier to obtain a uniform phase-separated structure.

[0053] The weight-average molecular weight Mw of the polyamide resin (A) is preferably 15,000 to 100,000, and more preferably 17,000 to 78,000. When Mw is 15,000 or more, the wet heat resistance is improved and the thermal cycling resistance is further improved. When Mw is 100,000 or less, the wettability to the adherend is improved and the adhesiveness is further improved.

[0054] The acid value of the polyamide resin (A) is preferably 0.25 to 30 mgKOH / g, more preferably 0.5 to 28 mgKOH / g, even more preferably 3 to 25 mgKOH / g, and particularly preferably 4 to 20 mgKOH / g. By setting the acid value to 0.25 to 30 mgKOH / g, the dispersibility of the silica filler (C) and the thermally conductive filler (D) is improved, and they are uniformly dispersed in the curable composition, improving thermal cycling resistance. Furthermore, when the composition is cured, an appropriate crosslink density is obtained, further improving the adhesive strength to the semiconductor chip and thermal cycling resistance.

[0055] [Epoxy resin (B)] Epoxy resins are thermosetting resins that can be thermally cured due to the presence of epoxy groups, and among these, epoxy resin (B) is a resin that has at least one of a softening point of 50 to 120°C and a melting point of 70 to 120°C. Epoxy resin (B) undergoes thermal crosslinking through a curing treatment. Note that the softening point in the present invention refers to the temperature at which the epoxy resin softens, and is a value measured by a softening point test (ring and ball method) (measurement conditions: in accordance with JIS-2817). The melting point of an epoxy resin is measured by measuring its melting range using a capillary. The sample is filled into a capillary, heated at a constant rate, and the change in shape is visually observed to determine the melting range.

[0056] If the epoxy resin (B) itself has a reactive functional group such as a hydroxyl group, the epoxy resin (B) can form a crosslinked structure by itself. In addition to or instead of the self-crosslinking, a preferred embodiment is to thermally crosslink the polyamide resin (A) and the epoxy resin (B). The three-dimensional crosslinked structure formed by the thermal crosslinking of the polyamide resin (A) and the epoxy resin (B) provides excellent adhesive strength and even better thermal cycling resistance. Another preferred embodiment is to form a crosslinked structure between the compound (E) described below and the epoxy resin (B). These types of thermal crosslinking may be used alone or in combination.

[0057] The mass ratio of the polyamide resin (A) to the epoxy resin (B) is preferably (A):(B) = 0.5:99.5 to 50:50, more preferably 0.5:99.5 to 30:70. By achieving this ratio, it is possible to improve the moisture and heat resistance and to achieve a good balance between adhesive strength and thermal cycling resistance. From the viewpoint of improving adhesive strength after thermal cycling, it is preferable to increase the polyamide resin content within the range of (A):(B) = 0.5:99.5 to 50:50. On the other hand, to improve the properties after thermal cycling while bringing out the excellent properties of the epoxy resin (B) itself, it is preferable to have a low polyamide resin content. In the latter case, the preferred range is (A):(B) = 0.5:99.5 to 10:90, more preferably (A):(B) = 0.5:99.5 to 5:95. The total content of the polyamide resin (A) and the epoxy resin (B) in 100% by mass of the nonvolatile content in the curable composition is preferably 5.0 to 35.0% by mass, more preferably 7.5 to 15.0% by mass, and even more preferably 8.0 to 13.0% by mass.

[0058] The content of the epoxy resin (B) is preferably 4.0 to 30.0 mass% and more preferably 7.0 to 20.0 mass% based on 100 mass% of the nonvolatile content of the curable composition. By using this range, it is possible to improve the moisture and heat resistance and to exhibit a good balance between adhesive strength and thermal cycle resistance.

[0059] The epoxy resin (B) preferably has a repeating unit containing an aromatic ring. Furthermore, it is preferable that at least a portion of the aromatic rings in the repeating units contain an organic group containing an epoxy group as a substituent. The epoxy equivalent of the epoxy resin (B) is preferably 100 to 300 g / eq., and is preferably 200 g / eq. or more from the viewpoints of increasing rigidity, effectively promoting compatibility with the polyamide resin (A) of the resin component during melt molding, suppressing foaming in the cured product, and further improving crack resistance and moist heat resistance. It is more preferably 220 to 320 g / eq., and even more preferably 250 to 300 g / eq.

[0060] From the viewpoint of improving compatibility with the polyamide resin (A) during kneading, the epoxy resin (B) is preferably a monocyclic aromatic hydrocarbon having one ring, such as a benzene ring, rather than a polycyclic aromatic hydrocarbon such as naphthalene. Polyaromatic epoxy resins having multiple monocyclic aromatic hydrocarbons are also suitable. Furthermore, from the viewpoint of effectively forming a phase-separated structure between the polyamide resin (A) and the epoxy resin (B) during melt molding, an epoxy resin (B) containing a repeating unit structure is preferred. Examples of the epoxy resin (B) include bisphenol-type epoxy resins such as bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, and bisphenol S-type epoxy resins; novolac-type epoxy resins such as o-cresol novolac-type epoxy resins; biphenyl-type epoxy resins, naphthalene-type epoxy resins, naphthalene-containing novolac-type epoxy resins, dicyclopentadiene-type epoxy resins, phenol aralkyl-type epoxy resins, trisphenolmethane-type epoxy resins, and phenol-modified xylene resin-type epoxy resins; and the epoxy resins represented by the chemical formulas (5) to (10) described below.

[0061] Among these, from the viewpoint of improving the wet heat resistance and the thermal cycling properties, biphenyl type epoxy resins, o-cresol novolac type epoxy resins, trisphenolmethane type epoxy resins, dicyclopentadiene type epoxy resins, naphthalene-containing novolac type epoxy resins, phenol aralkyl type epoxy resins, and phenol-modified xylene resin type epoxy resins are preferred.

[0062] Suitable examples include epoxy resins represented by the following chemical formulas (5) to (10): In the formula, n is an integer, preferably 1 to 10, for example. [ka] [ka] [ka] [ka] [ka] [ka]

[0063] Two or more types of epoxy resins (B) may be used in combination. By using two or more types in combination, adhesive strength and thermal cycling resistance can be easily adjusted. For example, a phenol aralkyl type epoxy resin and a phenol-modified xylene resin type epoxy resin, or a phenol aralkyl type epoxy resin and a trisphenolmethane type epoxy resin are preferably used. In particular, a combination of a phenol aralkyl type epoxy resin and a phenol-modified xylene resin type epoxy resin, or a phenol aralkyl type epoxy resin and a trisphenolmethane type epoxy resin in a mass ratio of 2:8 to 8:2 is preferred, as it has appropriate compatibility with the polyamide resin (A) and improves adhesive strength and thermal cycling resistance.

[0064] [Silica filler (C) and thermally conductive filler (D)] The curable composition of this embodiment contains at least one of a silica filler (C) and a thermally conductive filler (D). By combining at least one of the silica filler (C) and the thermally conductive filler (D) with the polyamide resin (A) and the epoxy resin (B), mechanical strength and moisture absorption can be improved. Furthermore, at least one of the silica filler (C) and the thermally conductive filler (D) improves the thermal cycling properties of the cured product.

[0065] Examples of the silica filler (C) include fused crushed silica, fused spherical silica, crystalline silica, secondary agglomerated silica, etc. Fused spherical silica is preferred as the silica filler (C) because of its excellent fluidity. The thermally conductive filler (D) preferably has a high thermal conductivity at 20°C, 15 (W / m·K) or higher. Furthermore, a high volume resistivity is preferred, 10 to the power of 6 (Ω·cm) or higher. Suitable examples of the thermally conductive filler (D) include aluminum oxide, aluminum nitride, silicon nitride, boron nitride, and silicon carbide. Among these, aluminum oxide or boron nitride is preferred due to its availability. The type of boron nitride is not particularly limited. Examples include hexagonal boron nitride (h-BN), cubic boron nitride (c-BN), and wurtzite boron nitride. Among these, hexagonal boron nitride (h-BN) is preferred from the viewpoint of thermal conductivity. The shape of the boron nitride is not limited, but a flake shape is preferred. It may be primary particles or secondary particles formed by aggregation of primary particles. Examples of the thermally conductive filler (D) include molten crushed bodies, molten spheres, crystals, secondary aggregates, etc. Among these, molten spheres are preferred because of their excellent fluidity.

[0066] The silica filler (C) and the thermally conductive filler (D) preferably have an average particle size in the range of 1 to 50 μm, more preferably 5 to 30 μm, and even more preferably 10 to 22 μm. By making the average particle size 1 μm or more, the flexibility and pliability of the cured product are further improved. By making the average particle size 50 μm or less, there is an advantage that high loading is easy. The average particle size is the average particle size D 50 For example, a sample randomly extracted from a population is used and the measurement is performed using a laser diffraction / scattering particle size distribution analyzer.

[0067] The silica filler (C) and the thermally conductive filler (D) may be independently treated (pretreated) with a silane coupling agent, which improves the affinity with other materials and further improves the dispersibility of the silica filler (C) and / or the thermally conductive filler (D). Silane coupling agents are compounds having a hydrolyzable group and a reactive functional group. Examples of the hydrolyzable group include alkoxy groups having 1 to 6 carbon atoms, such as methoxy and ethoxy groups; acetoxy groups; and 2-methoxyethoxy groups. Among these, methoxy groups are preferred because volatile components, such as alcohols, generated by hydrolysis can be easily removed. Examples of the reactive functional group include a vinyl group, an epoxy group, a styryl group, a methacryl group, an acryl group, an amino group, a ureido group, a mercapto group, a sulfide group, and an isocyanate group, with an epoxy group being preferred.

[0068] Examples of the silane coupling agent include vinyl group-containing silane coupling agents such as vinyltrimethoxysilane and vinyltriethoxysilane; epoxy group-containing silane coupling agents such as 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane; styryl group-containing silane coupling agents such as p-styryltrimethoxysilane; methacryl group-containing silane coupling agents such as 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and 3-methacryloxypropyltriethoxysilane; acrylic group-containing silane coupling agents such as 3-acryloxypropyltrimethoxysilane; and N-2-(aminoethyl)-3-acryloxypropyltriethoxysilane. Examples of suitable coupling agents include amino group-containing silane coupling agents such as aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, and N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane; ureido group-containing silane coupling agents such as 3-ureidopropyltriethoxysilane; mercapto group-containing silane coupling agents such as 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane; sulfide group-containing silane coupling agents such as bis(triethoxysilylpropyl)tetrasulfide; and isocyanate group-containing silane coupling agents such as 3-isocyanatepropyltriethoxysilane. From the viewpoint of achieving excellent adhesive strength and thermal cycling resistance, phenylaminosilane treatment and / or vinylsilane treatment are preferred.

[0069] The method of treating the silica filler (C) with a silane coupling agent includes, for example, a wet method in which the silica filler (C) and the silane coupling agent are mixed in a solvent, and a dry method in which the silica filler (C) and the silane coupling agent are treated in a gas phase. The amount of the silane coupling agent to be treated is preferably about 0.1 to 1 part by mass per 100 parts by mass of the untreated silica filler (C).

[0070] The method for treating the thermally conductive filler (D) with the silane coupling agent and the amount of treatment are the same as those for the silica filler (C) described above.

[0071] The total amount of silica filler (C) and thermally conductive filler (D) (including the case of either one) is preferably 40% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, based on 100% by mass of the nonvolatile content of the curable composition. A content of 40% by mass or more further improves the thermal cycling properties of the cured product. The preferred upper limit of the content of silica filler (C) and thermally conductive filler (D) is 95% by mass. The curable composition may include either the silica filler (C) or the thermally conductive filler (D) alone, or both.

[0072] The silica filler (C) and the thermally conductive filler (D) may each independently be of a single type or of a combination of two or more types, but from the viewpoint of improving adhesive strength, it is preferable to include two or more types. The silica filler (C) may be any combination of two or more of fused crushed silica, fused spherical silica, crystalline silica, and secondary agglomerated silica. Examples of the silica filler (C) include a combination of two or more silica fillers with different average particle sizes, and a combination of two or more silica fillers with different surface treatments. The embodiment containing two or more types of thermally conductive filler (D) may be a combination of any two or more types selected from molten crushed bodies, molten spheres, crystals, and secondary aggregates. Also, examples include a combination of two or more types of thermally conductive filler (D) with different average particle sizes, and a combination of two or more types of thermally conductive filler (D) with different surface treatments. By using the silica filler (C) and the thermally conductive filler (D) in combination, not only the adhesiveness but also the thermal conductivity can be more suitably exhibited, and the thermal cycle can be made more excellent.

[0073] From the viewpoint of improving the filling property, it is preferable to combine two or more types of fused spherical silica with different average particle sizes. The average particle size ranges preferably include two types, one of 0.2 to 10 μm and the other of 10 to 100 μm, and the content ratio (mass ratio) of each silica filler (C) is preferably 5:95 to 95:5, more preferably 10:90 to 90:10. Using a content ratio in the range of 5:95 to 95:5 makes it easier to improve the filling property.

[0074] Similarly, in the case of the thermally conductive filler (D), from the viewpoint of improving the filling property, it is preferable to combine two or more types with different average particle sizes. The average particle size ranges preferably include two types, 0.2 to 10 μm and 10 to 100 μm, and the content ratio (mass ratio) of each thermally conductive filler (D) is the same as that of the silica filler (C).

[0075] [Compound (E)] The curable composition may contain, as an optional component, at least one compound (E) selected from the group consisting of an acid anhydride group-containing compound, an isocyanate compound, an aziridine compound, an amine compound, a phenolic compound, and a metal chelate. The compound (E) may be a high molecular weight compound or a low molecular weight compound.

[0076] An acid anhydride group-containing compound is a compound having an acid anhydride group, an isocyanate compound is a compound containing an isocyanate group, an aziridine compound is a compound having an aziridine group, an amine compound is a compound having an amino group, and a phenol compound is a compound having a structure in which a hydroxy group is directly bonded to an aromatic group (aromatic ring). A chelate compound is a complex formed when a multidentate ligand (chelating ligand) coordinates with a metal ion.

[0077] Compound (E) is a compound having a functional group that is more reactive with epoxy groups, or acts as a catalyst for epoxy groups, thereby promoting crosslinking, thereby more effectively improving adhesive strength and thermal cycling resistance.

[0078] The compound (E) is preferably contained in an amount of 1 to 50 parts by mass, more preferably 3 to 30 parts by mass, and even more preferably 3 to 20 parts by mass, relative to 100 parts by mass of the total amount of epoxy resins. Here, the total amount of epoxy resins refers to the sum of the epoxy resin (B) and epoxy resins other than the epoxy resin (B). The total amount of epoxy resins includes the liquid epoxy compound (F) described below.

[0079] Examples of the acid anhydride group-containing compound include 1,2,4,5-benzenetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5(tetrahydro-2,5-dioxo-3-furanyl)naphtho[1,2-c]furan-1,3-di Examples of suitable dianhydrides include ethylene glycol bisanhydrotrimellitate, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 1,4-bis(3,4-dicarboxyphenol)benzene dianhydride, p-phenylene bis(trimellitate anhydride), 4,4'-oxydiphthalic anhydride, 1,1'-biphenyl-2,3,3',4'-tetracarboxylic acid 2,3:3',4'-dianhydride, and dicyclohexyl-3,4,3',4'-tetracarboxylic acid dianhydride. Other examples include copolymers such as styrene-maleic anhydride copolymers and ethylene-maleic anhydride copolymers, and modified products such as acid anhydride-modified polypropylene. Examples of commercially available products include Rikacid (registered trademark, manufactured by New Japan Chemical Co., Ltd.), Zybond (registered trademark, manufactured by Polyscope Polymers), SMA (registered trademark) Resin (manufactured by Claybury USA), and Tafmer (registered trademark, manufactured by Mitsui Chemicals, Inc.).

[0080] The isocyanate compound is not particularly limited, and examples thereof include aromatic polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates, etc. It is to be noted that a plurality of isocyanate group-containing compounds may be used in combination.

[0081] Examples of aromatic polyisocyanates include 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate (TDI), 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), 2,4-diphenylmethane diisocyanate, 4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatodiphenylmethane, 1,5-naphthylene diisocyanate, 4,4',4''-triphenylmethane triisocyanate, m-isocyanatophenylsulfonyl isocyanate, and p-isocyanatophenylsulfonyl isocyanate.

[0082] Examples of aliphatic polyisocyanates include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 1,6,11-undecane triisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2,6-diisocyanatomethyl caproate, bis(2-isocyanatoethyl) fumarate, bis(2-isocyanatoethyl) carbonate, and 2-isocyanatoethyl-2,6-diisocyanatohexanoate.

[0083] Examples of alicyclic polyisocyanates include isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (H12-MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate (hydrogenated TDI), bis(2-isocyanatoethyl)-4-cyclohexene-1,2-dicarboxylate, 2,5-norbornane diisocyanate, and 2,6-norbornane diisocyanate.

[0084] Other examples include trimethylolpropane adducts of diisocyanates, biuret products obtained by reaction with water, and trimers having an isocyanurate ring.

[0085] The blocked isocyanate compound is not particularly limited, as long as it is a blocked isocyanate group-containing compound in which the isocyanate group in the isocyanate group-containing compound is protected with ε-caprolactam, MEK oxime, or the like. Specific examples include compounds in which the isocyanate group of the isocyanate group-containing compound is blocked with ε-caprolactam, MEK oxime, cyclohexanone oxime, pyrazole, phenol, or the like. In particular, hexamethylene diisocyanate trimer having an isocyanurate ring and blocked with MEK oxime or pyrazole is highly preferred when used in this embodiment because it not only has excellent storage stability but also excellent adhesive strength to bonding materials such as polyimide and copper, and excellent solder heat resistance.

[0086] Examples of the aziridine compound include N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxide), N,N'-toluene-2,4-bis(1-aziridinecarboxide), bisisophthaloyl-1-(2-methylaziridine), tri-1-aziridinylphosphine oxide, N,N'-hexamethylene-1,6-bis(1-aziridinecarboxide), trimethylolpropane-tri-β-aziridinylpropionate, tetramethylolmethane-tri-β-aziridinylpropionate, tris-2,4,6-(1-aziridinyl)-1,3,5-triazine, trimethylolpropane tris[3-(1-aziridinyl)propionate], and trimethylolpropane. tris[3-(1-aziridinyl)butyrate], trimethylolpropane tris[3-(1-(2-methyl)aziridinyl)propionate], trimethylolpropane tris[3-(1-aziridinyl)-2-methylpropionate], 2,2'-bishydroxymethylbutanol tris[3-(1-aziridinyl)propionate], pentaerythritol tetra[3-(1-aziridinyl)propionate], diphenylmethane-4,4-bis-N,N'-ethyleneurea, 1,6-hexamethylene bis-N,N'-ethyleneurea, 2,4,6-(triethyleneimino)-Sym-triazine, bis[1-(2-ethyl)aziridinyl]benzene-1,3-carboxylic acid amide. In particular, 2,2'-bishydroxymethylbutanol tris[3-(1-aziridinyl)propionate] is suitable because it can improve the heat resistance of the cured product while maintaining its flexibility.

[0087] Examples of the amine compound include polyamines having a dimer structure exemplified as the monomers of the polyamide resin (A), and other polyamines not having a dimer structure.

[0088] The type of phenol compound is not particularly limited, but a phenol resin having two or more phenolic hydroxyl groups per molecule is preferred. Examples of such phenol resins include bisphenol A type phenol resins, bisphenol F type phenol resins, phenol aralkyl type phenol resins, dicyclopentadiene type phenol resins, triphenylmethane type phenol resins, novolac type phenol resins, dicyclopentadiene type phenol resins, xylylene type phenol resins, and biphenyl type phenol resins.

[0089] Specific examples of metal chelates include aluminum chelate compounds, titanium chelate compounds, and zirconium chelate compounds. The central metal may be various metals such as iron, cobalt, and indium.

[0090] [Liquid epoxy compound (F)] The present curable composition may further contain, as an optional component, a liquid epoxy compound (F) that is liquid at room temperature of 25° C. (hereinafter also referred to as liquid epoxy compound (F)). Examples of the liquid epoxy compound (F) include bisphenol A type epoxy resins, bisphenol F type epoxy resins, biphenyl type epoxy resins, novolac type epoxy resins, dicyclopentadiene type epoxy resins, polyfunctional phenol-based epoxy resins, naphthalene type epoxy resins, phenol aralkyl-modified epoxy resins, alicyclic and alcohol-based glycidyl ethers, alicyclic and alcohol-based glycidyl amine-based epoxy resins, and alicyclic and alcohol-based glycidyl ester-based epoxy resins. By using the liquid epoxy compound (F), the processability of the curable composition can be improved, and the adhesive strength can be more effectively increased.

[0091] In view of the ease of improving the fluidity of the present curable composition, bisphenol F epoxy resins and phenol novolac epoxy resins are preferred. Specific examples include jER806 (bisphenol F epoxy resin, manufactured by Mitsubishi Chemical Corporation) and jER152 (phenol novolac epoxy resin, manufactured by Mitsubishi Chemical Corporation).

[0092] The liquid epoxy compound (F) allows easy adjustment of the crosslink density. It also acts as a binder for the silica filler (C) and the thermally conductive filler (D) when molding the curable composition into a sheet or granule, facilitating molding. When a liquid epoxy compound (F) is used, the content ratio (mass ratio) of the epoxy resin (B) to the liquid epoxy compound (F) is preferably epoxy resin (B):liquid epoxy compound (F) = 50:50 to 95:5, more preferably 60:40 to 90:10. The content of the liquid epoxy compound (F) is preferably 1 to 10 mass%, more preferably 1 to 5 mass%, based on 100 mass% of the nonvolatile content of the curable composition. By ensuring that the content is 1 mass% or more, the effect as a binding component of the curable composition is improved, and by ensuring that the content is 10 mass% or less, the moist heat resistance and heat-cooling cycle properties of the cured product after curing of the curable composition are improved.

[0093] [Release agent (G)] The curable composition may further contain a release agent (G). Addition of the release agent (G) is particularly preferred when molding using a mold. The use of the release agent (G) improves releasability from the mold of the thermoforming device. Examples of the release agent (G) include natural waxes, synthetic waxes such as Montan acid esters, higher fatty acids or their metal salts, paraffin, and polyethylene oxide. Examples of natural waxes include carnauba wax and candelilla wax. Examples of synthetic waxes include paraffin wax, microcrystalline wax, Fischer-Tropsch wax, and polyethylene wax. When using a release agent (G), one type may be used alone, or two or more types may be used in combination. When the release agent (G) is used, the content thereof is, for example, 0.1 to 0.5 mass %, and preferably 0.2 to 0.3 mass %, relative to 100 mass % of the nonvolatile content of the curable composition.

[0094] Other Fillers The curable composition may contain other fillers (H) in addition to the silica filler (C) and the thermally conductive filler (D). Examples of the other fillers (H) include flame-retardant fillers and electromagnetic shielding fillers. Examples of the other fillers (H) include quartz glass, talc, aluminum hydroxide, magnesium hydroxide, and ferrite. The preferred average particle diameter D of the other fillers (H) is: 50 The surface treatment method is the same as that for the silica filler (C) described above. From the viewpoint of achieving other properties such as electromagnetic shielding, the content ratio (mass ratio) of the silica filler (C) and the thermally conductive filler (D) to the other fillers is preferably 50:50 to 90:10, however, it is preferable that the total content of the silica filler (C), the thermally conductive filler (D) and the other fillers does not exceed 95% by mass relative to 100% by mass of the curable composition.

[0095] [Other optional ingredients] The curable composition may further contain additives within the scope of the present invention. For example, a polyamide resin that does not fall under the category of polyamide resin (A) or an epoxy resin that does not fall under the category of epoxy resin (B) or liquid epoxy compound (F) may be used. Suitable examples include epoxy resins with a softening point of less than 50°C.

[0096] Thermoplastic resins (elastomers) can also be used. Other examples of the additives include dyes, pigments (e.g., carbon black), flame retardants, antioxidants, polymerization inhibitors, antifoaming agents, leveling agents, ion scavengers, moisturizing agents, viscosity modifiers, preservatives, antibacterial agents, antistatic agents, antiblocking agents, ultraviolet absorbers, infrared absorbers, and electromagnetic wave shielding agents.

[0097] [Method for producing curable composition] The curable composition is obtained by kneading the respective blended components. For example, a solventless curable composition can be obtained by mixing the respective blended components and then melt-kneading them in a state that substantially does not contain a solvent. At this time, the composition may be formed into a desired shape such as a sheet, granules, pellets, powder, or tablet. Alternatively, the blended composition may be melt-kneaded to form an amorphous solid.

[0098] A sheet-like curable composition can be obtained, for example, by blending the components of a substantially solvent-free curable composition, melt-kneading the mixture using a roll or kneader, forming the kneaded mixture into a sheet, and then cooling it. Melt-kneading can be performed using a known kneader such as a mixing roll, a pressure kneader, or an extruder. Regarding the kneading conditions, the temperature is preferably equal to or higher than the softening point of each of the above-mentioned components, for example, 30 to 150°C, and, considering the thermosetting properties of the epoxy resin, preferably 40 to 140°C, and more preferably 60 to 120°C. The kneading time is, for example, 1 to 30 minutes, and preferably 5 to 15 minutes. The kneading is preferably carried out under reduced pressure, which allows degassing and prevents gas from entering the kneaded material. The pressure under reduced pressure is preferably 0.1 kg / cm. 2 Less than 0.05 kg / cm, more preferably 0.05 kg / cm 2 The lower limit of the reduced pressure is not particularly limited, but is, for example, 1×10 -4 kg / cm 2 That's all.

[0099] When the kneaded material is subjected to plastic processing to form a curable composition sheet, it is preferable to perform plastic processing on the melt-kneaded kneaded material while it is still in a high-temperature state without cooling. The plastic processing method is not particularly limited, and examples thereof include flat-plate pressing, T-die extrusion, screw-die extrusion, roll rolling, roll kneading, inflation extrusion, co-extrusion, and calendar molding. Examples of molding machines include T-die screw molding machines, compression mold molding machines, and calendar molding machines. The plastic processing temperature is preferably equal to or higher than the softening points of the above-mentioned components, and, taking into consideration the thermosetting and moldability of the epoxy resin, is, for example, 40 to 150°C, preferably 50 to 140°C, and more preferably 70 to 130°C. A protective film may be laminated on the surface of the sheet-form curable composition. The sheet-form curable composition may be in the form of a sheet or a roll that can be wound up.

[0100] The thickness of the sheet can be adjusted appropriately depending on the application, but is preferably 50 μm or more, more preferably 70 μm or more. By making the thickness 50 μm or more, when used for sealing an IC chip and its surrounding wiring layer and insulating layer together, for example, it becomes easy to completely cover the target to be covered, and an excellent cured product can be obtained.

[0101] The resulting sheet-like curable composition may be pulverized into powder or granules, and the powder or granules may be compressed into tablets.

[0102] The powdery, granular, or tablet-like curable composition may be produced directly from the kneaded product by melt-kneading using a roll or kneader without passing through a sheet. This method can be carried out using, for example, a kneader, a roll mill, a super mixer, a Henschel mixer, a Schuggie mixer, a vertical granulator, a high-speed mixer, a Farmatrix, a ball mill, a steel mill, a sand mill, a vibration mill, an attritor, a Banbury mixer, or a batch kneader; a twin-screw extruder, a single-screw extruder, or a rotor-type twin-screw kneader.

[0103] Specifically, examples of such methods include a method in which a melt-kneaded curable composition is supplied to the inside of a rotor consisting of a cylindrical outer periphery with a plurality of small holes and a disk-shaped bottom, and the curable composition is forced to pass through the small holes by centrifugal force generated by rotating the rotor; a method in which the raw material components of the curable composition are premixed in a mixer, then heated and kneaded using a kneading machine such as a roll, kneader, or extruder, and then cooled and pulverized to produce a pulverized product, from which coarse particles and fine powder are removed using a sieve; and a method in which the raw material components of the curable composition are premixed in a mixer, then heated and kneaded using an extruder equipped with a die having a plurality of small holes at the tip of the screw, and the molten resin extruded in the form of strands through the small holes in the die is cut with a cutter that rotates and slides approximately parallel to the die surface.

[0104] When the composition is in granular form, the particle size is preferably 70 to 500 μm. By setting the particle size to 70 to 500 μm, it becomes easier to adjust the thickness of the composition after curing while suppressing contamination by powder. The particle size is measured by extracting and quantifying particles using an image binarization method under a microscope.

[0105] Alternatively, the components may be mixed with a solvent to prepare a varnish, or the raw material components may be kneaded to prepare a curable composition, which is then dissolved or dispersed in an organic solvent to prepare a varnish, and the varnish may then be applied and dried to obtain a sheet-like curable composition. Examples of application methods include coating using a coater such as a comma coater or a die coater, and printing methods such as stencil printing and gravure printing.

[0106] Similarly to the above, the sheet-shaped curable composition produced via the varnish may be further pulverized into granules or powder. Furthermore, the granules or powder may be molded into a desired shape such as a tablet (pellet). The varnish may also be spray-dried to form granules, powder, or the like. The shape of the curable composition can be appropriately selected depending on the application. For example, from the viewpoint of mold filling properties, granular or powdery forms are preferred, and from the viewpoint of productivity, sheet forms are preferred.

[0107] [[Cured product and method for producing the same]] A cured product can be obtained by hot melt molding the solventless thermosetting curable composition of this embodiment and then curing it. Hot melt molding and curing may be performed simultaneously, or the curing may be performed after hot melt molding. The term "cured product" as used herein refers to a state in which the composition has been cured to the extent that further heating does not substantially promote the curing reaction. During melt kneading to produce the curable composition, a portion of the composition may undergo a curing reaction, but this does not include a state in which the composition can be cured by further heating. When the curable composition is used to encapsulate, for example, an IC chip, stress relaxation occurs due to the dimer structure contained in the polyamide resin (A) during the process of applying heat to soften and flow the molded product. However, stress is distributed in the in-plane and longitudinal directions of the encapsulated product, resulting in effects such as suppressing adhesive strength loss, foaming, and cracking. Pressure may be applied during melt molding.

[0108] Compared to a method of directly applying a solvent-containing resin composition to, for example, an IC chip or its surrounding wiring layer or insulating layer, drying, and curing to obtain a cured product, a method of thermally melting a solventless curable composition, molding it, and then heat-treating it to obtain a cured product effectively prevents the polyamide resin (A) in the composition from being unevenly distributed at the air interface, etc. As a result, stress relaxation properties are fully exhibited, foaming is suppressed, and a cured product with excellent crack resistance and flexural strength can be obtained. Furthermore, the solventless curable composition of this embodiment can promote uniform dispersion of the polyamide resin (A) in the composition, making it possible to reduce moisture absorption within the composition and improve the solder heat resistance of the cured product after humidification.

[0109] The heat curing temperature is preferably 150 to 230°C, and the heating time is preferably 30 to 180 minutes. The epoxy resin (B) has a softening point of 50 to 120°C and a melting point of 70 to 120°C, and forms three-dimensional crosslinks by heat to become a cured product. Pressure may be applied in addition to heat when the resin is melted. The application of heat and pressure makes it easier to soften and fluidize the resin. In addition, the dimer structure contained in the polyamide resin (A) can promote stress relaxation.

[0110] If the polyamide resin (A) has reactive functional groups, they are incorporated into the three-dimensional crosslinking of the epoxy resin (B). Similarly, if the liquid epoxy compound (F) is contained, these are also incorporated into the crosslinking.

[0111] The glass transition temperature (Tg) of the cured product is preferably from 100 to 200° C., more preferably from 120 to 190° C. By setting it within the above range, the thermal cycling property is improved.

[0112] When the curable composition of this embodiment is in sheet form, for example, the sheet is placed on a semiconductor chip, melt-molded by thermocompression bonding, and cured to obtain an IC package in which the semiconductor chip is covered with a cured product that functions as an encapsulating resin. When the curable composition of this embodiment is in tablet form, for example, the tablet is poured into a mold in which a semiconductor chip is set while being melted and flowed, and an IC package in which the cured product of the curable composition serves as the encapsulating resin is obtained through a molding step and a curing step.

[0113] In addition to the method of using a solventless curable composition as in the present invention, there is also a method of directly applying a solvent-containing varnish-like curable composition to a semiconductor chip or electronic component and curing it to obtain a cured product. This method has excellent processability because it can be produced by direct application. However, if a molded product contains a solvent, voids may occur during thermal curing, which may reduce reliability. Furthermore, peeling may occur between the adherend and the cured product due to the voids. Furthermore, the orientation component is likely to be unevenly distributed at the air interface, etc., which may reduce the uniformity of the composition.

[0114] On the other hand, according to this embodiment, it is possible to more effectively prevent the polyamide resin (A) from being unevenly distributed at the air interface, etc., compared to a method in which a varnish containing a solvent is directly applied to, for example, an IC chip or a wiring layer or an insulating layer therearound, dried, and then cured to obtain a cured product. Furthermore, according to the curable composition of this embodiment, a cured product is obtained through a process in which the curable composition is thermally melted, molded, and cured, and the cured product has excellent adhesion and moist heat resistance even after cold-hot recycling.

[0115] It is believed that the microphase-separated structure having a hard epoxy resin (B) phase and a polyamide resin (A) phase having a flexible dimer structure is promoted by thermal melting, and that this microphase-separated structure has a stress-relieving effect. Furthermore, it is believed that the microphase-separated structure thus obtained is stabilized by thermal crosslinking, and that the structure can be stabilized even under severe thermal conditions. From the viewpoint of further promoting the microphase-separated structure, when producing a solventless curable composition, a method of melt-kneading and, if necessary, molding is preferable to producing it from a solvent-containing varnish. It is also advantageous in that it minimizes the use of solvents. [Example]

[0116] The present invention will be described in more detail below, but the following examples do not limit the scope of the present invention. In the examples, "parts" means "parts by mass" and "%" means "% by mass." The blending amounts in the tables are in parts by mass.

[0117] <Acid value measurement> Accurately weigh approximately 1 g of sample into a stoppered Erlenmeyer flask and add 100 mL of cyclohexanone solvent. Add phenolphthalein solution as an indicator and leave for 30 seconds. Then, add 0.1N alcoholic potassium hydroxide solution until the solution turns pale pink. The acid value was calculated using the following formula (unit: mgKOH / g). Acid value (mgKOH / g)=(5.611×a×F) / S however, S: Amount of sample collected (g) a: Amount of 0.1N alcoholic potassium hydroxide solution consumed (mL) F: Potency of 0.1N alcoholic potassium hydroxide solution

[0118] <Amine value measurement> Approximately 1 g of sample was accurately weighed into a stoppered Erlenmeyer flask and dissolved in 100 mL of cyclohexanone solvent. A few drops of indicator, prepared separately by mixing 0.20 g of methyl orange dissolved in 50 mL of distilled water with 0.28 g of xylene cyano FF dissolved in 50 mL of methanol, were added and the mixture was left to stand for 30 seconds. The solution was then titrated with 0.1 N alcoholic hydrochloric acid until it turned blue-gray. The amine value was calculated using the following formula (unit: mg KOH / g). Amine number (mgKOH / g) = (5.611 x a x F) / S however, S: Amount of sample collected (g) a: Consumption volume of 0.1N alcoholic hydrochloric acid solution (mL) F: Potency of 0.1N alcoholic hydrochloric acid solution

[0119] <Method for measuring weight average molecular weight (Mw)> Mw was measured using a GPC (gel permeation chromatography) "GPC-101" manufactured by Showa Denko K.K. GPC is a liquid chromatography technique that separates and quantifies substances dissolved in a solvent (THF; tetrahydrofuran) based on their molecular size. Measurements in this invention were performed using two "KF-805L" (Showa Denko K.K. GPC columns: 8 mm ID x 300 mm size) connected in series under the following conditions: sample concentration 1% by mass, flow rate 1.0 mL / min, pressure 3.8 MPa, column temperature 40°C. Weight-average molecular weight (Mw) was determined in polystyrene equivalent. Data analysis was performed using the manufacturer's built-in software to calculate the calibration curve, molecular weight, and peak area, and the weight-average molecular weight was determined for the retention time range of 17.9 to 30.0 minutes.

[0120] <Method for measuring the glass transition temperature of polyamide resin (A)> Polyamide resin varnish was prepared by dissolving polyamide resin in cyclohexanone to a nonvolatile content of 35%. This varnish was applied to a heat-resistant release film using a 10-mil doctor blade and dried at 130°C for 10 minutes to obtain a 25-μm-thick polyamide resin film, which was used as a sample for measuring the glass transition temperature. Tan δ was measured using a dynamic viscoelasticity measuring device over a temperature range of -50 to 200°C to determine the glass transition temperature. Dynamic viscoelasticity measuring device: DVA-200 (manufactured by IT Measurement and Control Co., Ltd.) Heating rate: 10℃ / min Measurement frequency: 10Hz Grip length: 15mm Width: 5mm

[0121] <Synthesis of polyamide resin> [Polyamide resin (A-1)] A four-neck flask equipped with a stirrer, a reflux condenser with a Dean-Stark apparatus, a nitrogen inlet tube, and a thermometer was charged with 481.0 g (0.901 mol) of Priamine 1075 as a 36-carbon dimer diamine, 187.5 g (0.938 mol) of 3,4'-diaminodiphenyl ether as another diamine, 139.1 g (0.952 mol) of adipic acid as a polybasic acid, and 192.4 g (0.952 mol) of sebacic acid, and the contents were stirred. Once the heat generation subsided, the mixture was gradually heated to allow the reaction to proceed. While removing water generated during the reaction, the internal temperature was raised to 230 °C and maintained at that temperature for 4 hours. The reaction was then completed by maintaining the temperature at a reduced pressure of approximately 2 kPa for 2 hours. A polyamide resin (A-1) was obtained having a weight average molecular weight of 30,000, an acid value of 11.4 mg KOH / g, an amine value of 0.2 mg KOH / g, and a Tg of 21° C. The total content of dimer diamine and dimer acid constituting the polyamide resin (A) was 48.1% by mass.

[0122] [Polyamide resins (A-2 to A-13)] Polyamide resins were obtained by synthesis in the same manner as for polyamide resin (A-1) according to the compositions and parts by mass of ingredients shown in Table 1. The properties of the resulting polyamide resins are shown in Table 1.

[0123] [Polyamide resin (A-14)] A four-neck flask equipped with a stirrer, a reflux condenser with a Dean-Stark apparatus, a nitrogen inlet tube, and a thermometer was charged with 672.6 g (1.26 mol) of Priamine 1075 as a 36-carbon dimer diamine, 59.1 g (0.295 mol) of 3,4'-diaminodiphenyl ether as another diamine, 194.5 g (1.33 mol) of adipic acid as a polybasic acid, and 59.1 g (0.292 mol) of sebacic acid, and the contents were stirred. Once the heat generation subsided, the contents were gradually heated to allow the reaction to proceed. While removing water generated during the reaction, the internal temperature was raised to 230 °C and maintained at that temperature for 4 hours. The reaction was then continued at that temperature for 2 hours under a reduced pressure of approximately 2 kPa. The internal temperature was then lowered to 180°C, 14.7 g (0.137 mol) of benzylamine was added, and the temperature was gradually raised to 240°C to complete the reaction. Polyamide resin (A-14) with a weight-average molecular weight of 30,000, an acid value of 0.5 mg KOH / g, an amine value of 0.6 mg KOH / g, and a Tg of 26°C was obtained.

[0124] The abbreviations in Table 1 are as follows: DA: Dimer diamine with 36 carbon atoms and a 6-carbon ring structure (dimer structure ratio: 95% or more, amine value: 210 mg KOH / g "Priamine 1075" manufactured by Croda Japan) Dacid: A dimer acid with 36 carbon atoms and a 6-carbon ring structure (dimer structure ratio: 95% or more, acid value: 197 mg KOH / g "Pripol 1009" manufactured by Croda Japan) DAPE: 3,4'-diaminodiphenyl ether AdA: adipic acid SeA: Sebacic acid 5-HIP: 5-hydroxyisophthalic acid

[0125] [Table 1]

[0126] [Example 1] The components were mixed according to the mixing ratios in Table 2, and mixed in a kneader at 100°C for 10 minutes under reduced pressure (0.01 kg / cm 2 ) to prepare a kneaded mixture. The kneaded mixture was then formed into a sheet of curable composition having a thickness of 300 μm by a plate pressing method.

[0127] [Examples 2 to 35], [Comparative Examples 1 to 4] The components were blended as shown in Tables 2 to 4 in the same manner as in Example 1, and a sheet-shaped curable composition was produced in the same manner as in Example 1.

[0128] Details of the materials used in the examples and comparative examples are shown below. Epoxy resin (B) with a softening point of 50 to 120°C and a melting point of 70 to 120°C. B-1: Trisphenolmethane type epoxy resin, softening point 54°C, manufactured by Nippon Kayaku Co., Ltd., EPPN-501H, EPW (epoxy equivalent weight) = 167. B-2: Phenol aralkyl type epoxy resin, softening point 58°C, manufactured by Nippon Kayaku Co., Ltd., NC-3000, EPW=275. B-3: Phenol-modified xylene resin type epoxy resin, softening point 65°C, manufactured by Mitsubishi Chemical Corporation, YX7700, EPW=270. B-4: Softening point 73°C, dicyclopentadiene type epoxy resin, manufactured by Nippon Kayaku Co., Ltd., XD-1000, EPW=253. B-5: Melting point 105°C, biphenyl type epoxy resin, manufactured by Mitsubishi Chemical Corporation, YX4000HK, EPW=185. B-6: Softening point 90°C, tetrakisphenolethane type epoxy resin, manufactured by Mitsubishi Chemical Corporation, jER1031S, EPW=200. B-7: Naphthalene-type epoxy resin with a softening point of 80°C, manufactured by DIC Corporation, HP-6000, EPW=250. B-8: Naphthalene-containing novolac epoxy resin with a softening point of 88°C, manufactured by Nippon Kayaku Co., Ltd., NC-7000L, EPW=231.

[0129] Silica filler (C) C-1: Spherical silica (manufactured by Admatechs, SO-E5, average particle size 1.5 μm, specific surface area 4 m 2 / g) C-2: Fused spherical silica (manufactured by Denka Co., Ltd., FB-105FC, average particle size d50: 12 μm) C-3: Fused spherical silica (manufactured by Admatechs, SO-25R, average particle size d50: 0.5 μm) C-4: Fused spherical silica (manufactured by Denka Co., Ltd., FB-950FC, average particle size d50: 22 μm) Thermally conductive filler (D) D-1: Fused spherical alumina (Denka, DAW-01, average particle size d50: 1.9 μm) D-2: Fused spherical alumina (Denka, DAW-10, average particle size d50: 12 μm) D-3: Boron nitride (manufactured by Denka, MGP, average particle size d50: 10 μm)

[0130] ·Compound (E) E-1: Triphenylmethane type phenolic resin, manufactured by Meiwa Kasei Co., Ltd., MEH-7500, OH equivalent = 97 g / eq. E-2: Xylylene-type phenolic resin, Meiwa Kasei Co., Ltd., MEHC-7800-SS, OH equivalent = 173 g / eq.

[0131] Liquid epoxy compound (F) that is liquid at 25°C F-1: Bisphenol F type epoxy resin, liquid at 25°C, jER806, manufactured by Mitsubishi Chemical Corporation, EPW=160

[0132] Other additives: curing catalyst (imidazole) J-1: Imidazole compound (2P4MZ, manufactured by Shikoku Chemicals Corporation)

[0133] <Method for measuring softening point> The softening point is measured by the ring and ball method in accordance with JIS K-2207. That is, a specified ring is filled with the sample and supported horizontally in a water bath or glycerin bath. A specified ball is placed in the center of the sample, and the bath temperature is raised at a rate of 5°C / min. The softening point is the temperature at which the sample encasing the ball touches the bottom plate of the ring stand.

[0134] [Table 2] [Table 3] [Table 4]

[0135] For the cured products of the curable compositions of each Example and Comparative Example, the evaluation results for Tg, moist heat resistance before and after the thermal cycling test, and adhesiveness are shown in Table 5. The measurement methods and evaluation criteria are as follows.

[0136] <Method for measuring the glass transition temperature Tg of a cured product> A 300 μm sheet of the curable composition prepared in the same manner as in Example 1 was thermally cured on a heat-resistant release film at 180°C for 60 minutes to prepare a sample for measuring the glass transition temperature. Tan δ was measured using a dynamic viscoelasticity measuring device over a temperature range of -50 to 200°C to determine the glass transition temperature. Dynamic viscoelasticity measuring device: DVA-200 (manufactured by IT Measurement and Control Co., Ltd.) Heating rate: 10℃ / min Measurement frequency: 10Hz Grip length: 15mm Width: 5mm

[0137] <Evaluation of humidity and heat resistance> A 300 μm thick sheet of the curable composition was sandwiched between 50 μm polyimide films (Kapton 200EN) and temporarily bonded using a laminator. The temperature was 90°C and the cylinder pressure was 0.3 MPa. After thermal lamination, a heat press (150°C x 1 MPa x 2 min) was performed, followed by post-baking (170°C x 2 hours) to obtain a cured product. This cured product was cut into strips measuring 10 mm wide and 120 mm long to obtain samples for the moist heat resistance test. These moist heat resistance test samples were allowed to absorb moisture for 24 hours in an environment of 40°C and 80% RH, then heated in a molten solder bath (temperature 260°C) for 10 seconds, and the appearance of the test sample was visually evaluated. The evaluation criteria were as follows. 5: Excellent (no bubbling and / or cracks observed in the moist heat resistance test sample). 4: Better (1 to 3 bubbles and / or cracks on the moist heat resistance test sample) 3: Excellent (4-5 bubbles and / or cracks on the moist heat resistance test sample) 2: Practical (6 to 10 bubbles and / or cracks on the moist heat resistance test sample) 1: Impractical (peeling was observed between polyimide films in the sample for the moist heat resistance test).

[0138] <Heat and humidity resistance after thermal cycling> The above-mentioned samples for the moist heat resistance test were prepared and subjected to the following temperature cycle test, and then the above-mentioned moist heat resistance test was carried out. The evaluation criteria were the same as those described above. Thermal cycle tester: TSE-11 (manufactured by Espec Corporation) Test temperature: -40℃ and 150℃ Exposure time: 30 minutes at each temperature Test cycle: 500 cycles

[0139] <Adhesive strength> The prepared sheet-like curable composition was cut into a 50 mm x 50 mm piece, and nine 5 mm x 5 mm x 300 μm Au-plated silicon chips were arranged on top of it in three vertical and three horizontal rows, with equal spacing between each chip. The sheet-like curable composition was placed in contact with the silicon surface of the silicon chip. To ensure close contact of the sheet-like curable composition in contact with the silicon chip, a 38 μm polyethylene terephthalate sheet with a silicone release treatment was placed opposite the silicon chip, and the chips were thermally laminated (temperature: 80°C, cylinder pressure: 0.3 MPa) using a thermal lamination tester. After thermal lamination, an incision was made around the periphery of the silicon chip with a utility knife, and a sheet-like curable composition was temporarily adhered to one side of the silicon chip to prepare an adhesion test sample. A gold-plated copper frame substrate was prepared as the adherend, and a silicon chip with a sheet-shaped curable composition temporarily adhered thereto was placed on top of it. The substrate was then heat-pressed (150°C x 1 MPa x 2 min), followed by post-baking (170°C x 2 hours) to prepare a sample for the adhesion test.

[0140] This silicon chip bonded to a copper frame substrate was evaluated using a bond tester (Nordson Advanced Technologies, product name: Dage4000-PXY). Measurement conditions were a measurement speed of 100 μm / s and a measurement height of 100 μm. The arithmetic mean of the adhesive strength measured at three points is shown in Table 2. The higher the value, the higher the adhesiveness of the cured product to the silicon chip and adherend. The evaluation criteria are as follows: 5: Excellent (adhesion strength of 10 N / mm or more). 4: Better (adhesion strength is 7N / mm or more and less than 10N / mm). 3: Excellent (adhesion strength is 5N / mm or more and less than 7N / mm). 2: Practical (adhesive strength is 3N / mm or more and less than 5N / mm). 1: Impractical (adhesion strength less than 3 N / mm).

[0141] <Adhesive strength after thermal cycling> The above adhesive strength test samples were prepared and subjected to the following temperature cycle test, and then the above adhesive strength test was carried out. The evaluation criteria were the same as above. Thermal cycle tester: TSE-11 (manufactured by Espec Corporation) Test temperature: -40℃ and 150℃ Exposure time: 30 minutes at each temperature Test cycle: 500 cycles

[0142] [Table 5]

[0143] As shown in Table 5, it was confirmed that the cured product obtained from the curable composition according to this example had excellent adhesiveness and moisture resistance before and after thermal cycling.

[0144] <Bending strength> The obtained resin composition was placed in an injection molding machine (manufactured by Toshiba Machine Co., Ltd.) and molded into strip test pieces at a temperature of 190°C. The strip test pieces conformed to the Type B2 (80 mm long x 10 mm wide x 4 mm thick) standard described in JIS K7139. The bending strength of the prepared strip test pieces was measured using a fully automatic bending tester, Bendograph II (manufactured by Toyo Seiki Co., Ltd.), in accordance with JIS K7171. The bending strength was calculated from the bending stress σ obtained in a three-point bending test. When the bending load F (unit: N), the distance between supports L (unit: mm), the specimen width b (unit: mm), and the specimen thickness h (unit: mm) are used, the bending stress σ is calculated as (3×F×L) / (2×b×h×h). The bending stress σmax at which the bending load F reached its maximum value was determined as the bending strength (unit: N / mm 2 = MPa). The higher the bending strength, the greater the rigidity, making the molded product less likely to deform when a load is applied.

[0145] [Table 6]

[0146] As shown in Example 2 and Comparative Example 4, the cured products of the present examples were found to have superior bending strength compared to cured products prepared from varnish-type curable compositions. Furthermore, it was confirmed that superior results were obtained in terms of moisture and heat resistance and adhesion before and after thermal cycling.

[0147] [[Industrial Applicability]] The curable composition according to the present embodiment has excellent adhesive properties and moist heat resistance even after thermal cycling, making it suitable for use as an insulating resin material, including semiconductor chip encapsulants, adhesives, underfills, and potting materials. Furthermore, the curable composition has excellent bending strength, making it particularly suitable as an insulating resin material for thin film applications. Furthermore, the curable composition has excellent adhesion to metals, making it suitable for applications such as copper-clad laminates, bonding sheets for forming wiring boards, and cover coats for flexible substrates.

Claims

1. A curable composition for melt molding that exhibits thermosetting properties, The composition comprises a polyamide resin (A) having a dimer structure derived from at least one of a dimer acid and a dimer diamine, an epoxy resin (B), and at least one of a silica filler (C) and a thermally conductive filler (D), the total amount of the dimer acid and the dimer diamine is 50 to 100% by mass based on 100% by mass of all the monomers used in the polymerization of the polyamide resin (A), The epoxy resin (B) satisfies at least one of a softening point of 50 to 120°C and a melting point of 70 to 120°C, The polyamide resin (A) is blended in an amount of 0.1% by mass or more and less than 0.6% by mass based on 100% by mass of the nonvolatile content, the mass ratio of the polyamide resin (A) to the epoxy resin (B), (A):(B), is 0.5:99.5 to 5:95; A curable composition in which the total amount of the silica filler (C) and the thermally conductive filler (D) (including the case where only one of the silica filler (C) and the thermally conductive filler (D) is present) is 40 mass% or more relative to 100 mass% of the nonvolatile content.

2. 2. The curable composition according to claim 1, wherein the polyamide resin (A) has a glass transition temperature of 0 to 90°C.

3. 3. The curable composition according to claim 1, wherein the polyamide resin (A) has a weight average molecular weight of 15,000 to 100,000.

4. The curable composition according to any one of claims 1 to 3, further comprising a compound (E) which is at least one selected from the group consisting of an acid anhydride group-containing compound, an isocyanate compound, an aziridine compound, an amine compound, a phenol compound, and a metal chelate.

5. The curable composition according to any one of claims 1 to 4, further comprising a liquid epoxy compound (F) that is liquid at 25°C.

6. The curable composition according to any one of claims 1 to 5, wherein at least one of the silica filler (C) and the thermally conductive filler (D) contains two or more types.

7. The curable composition according to any one of claims 1 to 6, which is in the form of a sheet, powder, granules or tablet.

8. The curable composition according to any one of claims 1 to 7, which is a solvent-free composition.

9. A cured product obtained by molding the curable composition according to any one of claims 1 to 8 by thermal melting and curing it.

10. The cured product according to claim 9, which has a glass transition temperature of 100 to 200°C.

11. The composition comprises a polyamide resin (A) having a dimer structure derived from at least one of a dimer acid and a dimer diamine, an epoxy resin (B), and at least one of a silica filler (C) and a thermally conductive filler (D), The polyamide resin (A) is blended in an amount of 0.1% by mass or more and less than 0.6% by mass based on 100% by mass of the nonvolatile content, the mass ratio of the polyamide resin (A) to the epoxy resin (B), (A):(B), is 0.5:99.5 to 5:95; the total amount of the silica filler (C) and the thermally conductive filler (D) (including the case where only one of the silica filler (C) and the thermally conductive filler (D) is used) is 40% by mass or more relative to 100% by mass of the nonvolatile content; the total content of the dimer acid and the dimer diamine is 50 to 100% by mass based on 100% by mass of all monomers constituting the polyamide resin (A), The epoxy resin (B) satisfies at least one of a softening point of 50 to 120°C and a melting point of 70 to 120°C, A method for producing a cured product, comprising the steps of: molding a curable composition exhibiting thermosetting properties by thermal melting; and thermally curing the composition.

12. The method for producing a cured product according to claim 11 , wherein the curable composition is a solventless type.

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