Conductive epoxy resin composition for copper bonding

Abstract

The present disclosure is directed to an electrically conductive epoxy resin composition, and its cured product and uses, particularly for bonding copper substrates, and a semiconductor device comprising the cured product.

Description

[Technical Field]

[0001] The present invention relates to conductive epoxy resin compositions and cured products, and uses thereof, particularly for bonding copper substrates, and semiconductor devices containing the cured products. [Background technology]

[0002] Conductive epoxy resin adhesives are used for a variety of purposes in the manufacture and assembly of semiconductor packages, such as bonding integrated circuit chips to lead frames and other substrates. It is important that the cured adhesive exhibits high adhesion, high thermal conductivity, high moisture resistance, good temperature stability, and excellent reliability.

[0003] Conventional one-component conductive epoxy resin adhesives typically contain conductive fillers, epoxy resins, and curing agents. However, epoxy resins can be brittle, and other resins have been evaluated and used to provide flexibility, hydrophobicity, and other properties to die attach adhesives. In particular, conductive epoxy resin adhesives do not exhibit strong adhesion to copper substrates, especially at high temperatures (e.g., above 260°C). Summary of the Invention [Problem to be solved by the invention]

[0004] Therefore, there remains a need to develop a conductive epoxy resin adhesive capable of bonding copper substrates that has good adhesion at high temperatures, especially above 260°C. [Means for solving the problem]

[0005] After extensive research, the present inventors have found that the above problems can be solved by a conductive epoxy resin composition comprising: (A) at least one epoxy resin system comprising: (A1) at least one epoxy resin having at least two glycidyloxy group-containing aromatic groups bonded to each other by a divalent endocyclic hydrocarbon group or an aryl group and, optionally, a C1-C6 alkylene group; and (A2) at least one resorcinol diglycidyl ether resin present in an amount of 0.2 to 5.0% based on the total weight of the composition; (B) at least one acid anhydride curing agent; (C) optionally, at least one solvent; (D) at least one conductive filler; and (E) optionally, at least one catalyst.

[0006] In another aspect of the present invention, there is provided a cured product of the conductive epoxy resin composition of the present invention.

[0007] In a further aspect of the present invention, there is provided a semiconductor device comprising a cured product of the conductive adhesive of the present invention.

[0008] In yet another aspect of the present invention, there is provided the use of the conductive epoxy resin composition and a cured product of the conductive epoxy resin composition in the manufacture of semiconductor packages or microelectronic devices. DETAILED DESCRIPTION OF THE INVENTION

[0009] Those skilled in the art will appreciate that the present invention describes only exemplary embodiments and is not intended to limit the broader aspects of the present invention. Each aspect so described can be combined with any other aspect unless expressly stated to the contrary. In particular, any feature indicated as being preferred or advantageous can be combined with any other feature indicated as being preferred or advantageous.

[0010] Unless otherwise specified, in the context of the present invention, the terms used should be construed in accordance with the following definitions.

[0011] Unless otherwise specified, as used herein, the terms "a," "an," and "the" include both singular and plural referents.

[0012] As used herein, the terms "comprising" and "comprises" are synonymous with "including," "includes," or "containing," and are inclusive or open-ended and do not exclude additional, unrecited members, elements, or method steps.

[0013] Unless otherwise specified, recitation of numerical endpoints includes not only the recited endpoint but all numbers and fractions subsumed within each range.

[0014] All documents cited herein are incorporated by reference in their entirety.

[0015] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the meaning commonly understood by one of ordinary skill in the art to which this invention belongs.

[0016] The present invention relates to an electrically conductive epoxy resin composition comprising: (A) at least one epoxy resin system comprising: (A1) at least one epoxy resin having at least two glycidyloxy group-containing aromatic groups bonded to each other by a divalent endocyclic hydrocarbon group or an aryl group and, optionally, a C1-C6 alkylene group; and (A2) at least one resorcinol diglycidyl ether resin present in an amount of 0.2 to 5.0% based on the total weight of the composition; (B) at least one acid anhydride curing agent; (C) optionally, at least one solvent; (D) at least one conductive filler; and (E) optionally, at least one catalyst.

[0017] [(A) Epoxy resin] According to the present invention, one notable feature is that the epoxy resin system (A) contained in the conductive epoxy resin composition comprises: (A1) at least one epoxy resin having at least two glycidyloxy group-containing aromatic groups bonded to each other by a divalent endocyclic hydrocarbon group or an aryl group and, optionally, a C1-C6 alkylene group; and (A2) at least one resorcinol diglycidyl ether resin present in an amount of 0.2-5.0 wt %, based on the total weight of the composition, which dramatically improves adhesion in bonding copper substrates at high temperatures.

[0018] (A1) Epoxy resin According to the present invention, the epoxy resin (A1) has at least two glycidyloxy-containing aromatic groups bonded to each other by a divalent endocyclic hydrocarbon group or an aryl group and, optionally, a C1-C6 alkylene group.

[0019] The glycidyloxy group-containing aromatic group may have various structures, including, but not limited to, monofunctional glycidyloxy group-containing phenols, polyfunctional glycidyloxy group-containing phenols, monofunctional glycidyloxy group-containing naphthalene groups, polyfunctional glycidyloxy group-containing naphthalene groups, and combinations thereof. Specific examples are represented by the following structural formulas Ep1 to Ep9: [ka]

[0020] In the present invention, the glycidyloxy group-containing aromatic group is not limited to the above structural formulas Ep1 to Ep9. In other embodiments, the glycidyloxy group-containing aromatic group may be a triglycidyl group or a tetraglycidyl group-containing phenol or naphthalene group.

[0021] In these above structures, when there are two or more bonds to other structural moieties on the naphthalene group, these bonds may be on the same atom or on different atoms.

[0022] In the present invention, the epoxy resin (A1) has at least two glycidyloxy-containing aromatic groups bonded to each other by a divalent endocyclic hydrocarbon group or an aryl group and, optionally, a C1-C6 alkylene group, and this bond can be any desired combination of bond types.

[0023] In a preferred embodiment, the epoxy resin (A1) has at least two glycidyloxy group-containing aromatic groups bonded to each other by a divalent endocyclic hydrocarbon group. Examples of the divalent endocyclic hydrocarbon group can be represented by the following structural formulas X1 to X3: [ka] [Here, there may be multiple R per ring, and each R independently represents a hydrogen atom or a methyl group; * represents a bonding site to the glycidyloxy group-containing aromatic group.]

[0024] In some embodiments, the epoxy resin (A1) has at least two glycidyloxy-containing aromatic groups bonded to each other by an aryl group. As used herein, the term "aryl" refers to a polyunsaturated aromatic substituent that may be monocyclic or polycyclic (preferably 1 to 3 rings) that are fused or covalently linked. Examples of aryl groups include, but are not limited to, phenyl, tolyl, xylyl, and 4-biphenyl.

[0025] In a preferred embodiment, the epoxy resin (A1) has at least two glycidyloxy group-containing aromatic groups bonded to each other by an aryl group and a C1-C6 alkylene group. Examples of C1-C6 alkylene groups include the following: -CH2-, -CH2CH2-, -CH2CH2CH2-, -CH(CH3)CH2-, -CH(C2H5)CH2-, -CH2CH2CH2CH2-, -C(CH3)2CH2-, -CH(CH3)CH2CH2-, -CH2CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -CH2CH2CH2CH2CH2-, -CH2CH(CH3)CH2CH2-, -CH2CH(CH3)CH2CH2-, -C(CH3)2CH2CH2-, -CH2C(CH3)2CH2-, -CH(C2H5)CH2CH2-, -CH2CH(C2H5)CH2-, -CH(CH3)CH( CH3)CH2-, -CH2CH2CH2CH2CH2CH2-, -CH(CH3)CH2CH2CH2CH2-, -CH2CH(CH3)CH2CH2CH2-, -CH2CH2CH(CH3)CH2CH2-, -C(CH3)2CH2CH2CH2-, -CH2C(CH3)2CH2CH2-, -CH(CH3)CH( CH3)CH2CH2-, -CH(CH3)CH2CH(CH3)CH2-, -CH(CH3)CH2CH2CH(CH3)-, -CH2CH(CH3)CH2CH(CH3)-, -CH2CH(CH3)CH(CH3)CH2-, -CH(C2H5)CH2CH2CH2- and -CH2CH(C2H5)CH2CH2-.

[0026] Specific examples of the combination of an aryl group and a C1 to C6 alkylene group include, but are not limited to, the following: a phenylmethyl group, a 2-methylbiphenyl group, a 3-methylbiphenyl group, a 4-methylbiphenyl group, a 2-methylnaphthalene group, a 3-methylnaphthalene group, a 4-methylnaphthalene group, and groups represented by the following structural formulas X4 to X9: [ka] [In the formula, each R' independently represents a C1 to C6 alkylene group, preferably a C1 to C3 alkylene group, more preferably a methylene group; and * represents a bonding site to the glycidyloxy group-containing aromatic group.]

[0027] Of these, structural formulas X1 and X7 are particularly preferred from the viewpoint of imparting toughness to the cured product of the composition.

[0028] In some embodiments, the epoxy resin (A1) may be selected from glycidyloxy group-containing biphenyl-type epoxy resins, glycidyloxy group-containing naphthalene-type epoxy resins, glycidyloxy group-containing epoxy resins having a divalent endocyclic hydrocarbon group, and combinations thereof.

[0029] Specific examples of the glycidyloxy group-containing biphenyl-type epoxy resin used as the epoxy resin (A1) in the present invention can be represented by the following structural formulas P1 and P2: [ka] [wherein n may be an average value of 1 to 5] [ka] [In the formula, n may be an average value of 1 to 5.]

[0030] A specific example of the glycidyloxy group-containing epoxy resin having a divalent endocyclic hydrocarbon group, which is used as the epoxy resin (A1) in the present invention, can be represented by the following structural formula P3: [ka] [In the formula, n may be an average value of 1 to 5.] In this structure, the diglycidyl group-containing phenol group can be attached to any structural site located on the octahydro-4,7-methano-indene.

[0031] The present invention has the above-described characteristic chemical structure, and an aromatic hydrocarbon structure or an endocyclic hydrocarbon structure that makes it tough and rigid, and as a result, the resin can provide high toughness while maintaining heat resistance.

[0032] In a preferred embodiment, the epoxy resin (A1) preferably has an epoxy equivalent in the range of 180 to 500 g / eq, preferably 200 to 400 g / eq.

[0033] In some embodiments, the epoxy resin (A1) can be prepared by a method known to those skilled in the art in which a phenolic resin is reacted with epichlorohydrin.

[0034] Examples of commercially available epoxy resins (A1) include the NC-3000 series (NC-3000 & NC-2000-L) and XD-1000 manufactured by Nippon Kayaku Co., Ltd.

[0035] Particularly preferably, the epoxy resin (A1) incorporated into the conductive epoxy resin composition is present in an amount of 1 to 15% by weight, preferably 3 to 10% by weight, based on the total weight of the composition.

[0036] (A2) Resorcinol diglycidyl ether resin According to the present invention, adding a specific amount (i.e., 0.2-5.0 wt %, preferably 0.5-3.0 wt %, more preferably 0.75-2.25 wt %, based on the total weight of the composition) of resorcinol diglycidyl ether resin (A2) to the epoxy resin (A1) provided in the present invention dramatically improves adhesion in bonding copper substrates.

[0037] Resorcinol diglycidyl ether (RDGE) has excellent oxygen barrier properties, as well as good chemical resistance, flexibility, and adhesion to a variety of substrates. RDGE-based resins may offer favorable conformer packing, improved hydrogen bonding, and inter- / intra-chain interactions within the resin compared to other epoxy resins.

[0038] In some embodiments, when the resorcinol diglycidyl ether resin comprises a monomer, resorcinol exhibits substantially low viscosity (e.g., about 200 to about 500 cps at about 25°C) and substantially high reactivity with epoxy resins. The resorcinol diglycidyl ether resin may have an epoxy equivalent weight of about 100 g to about 130 g. The resorcinol diglycidyl ether epoxy may have the general structure (I) shown below: [ka]

[0039] An example of a resorcinol diglycidyl ether resin is ERISYS® RDGE, a purified form of RDGE, available from CVC Thermoset Specialties. ERISYS® RDGE has a viscosity of approximately 300-500 cps at 25°C and a maximum of 10 ppm residual epichlorohydrin.

[0040] Particularly preferably, the resorcinol diglycidyl ether resin (A2) may be incorporated into the conductive epoxy resin composition and is present in an amount of 0.2 to 5.0 wt %, preferably 0.5 to 3.0 wt %, more preferably 0.75 to 2.25 wt %, based on the total weight of the composition.

[0041] In a preferred embodiment, the weight ratio of the resorcinol diglycidyl ether resin (A2):epoxy resin (A1) is 1:4 to 1:20, preferably 1:5 to 1:15, and more preferably 1:6 to 1:10.

[0042] [(B) Acid anhydride curing agent] According to the present invention, the conductive epoxy resin composition contains at least one acid anhydride curing agent (B). The acid anhydride curing agent (B) is not particularly limited as long as it can cure component (A).

[0043] Specific examples of acid anhydride curing agents include phthalic anhydride, maleic anhydride, trimellitic anhydride, pyromellitic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, nadic methyl anhydride, nadic anhydride, glutaric anhydride, methylhexahydrophthalic anhydride, and methyltetrahydrophthalic anhydride. These acid anhydrides can be used alone or in combination.

[0044] It is preferable to use phthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, etc.

[0045] The amount of acid anhydride curing agent (B) used is not particularly limited, but is usually preferably about 0.5 to 1.5 equivalents, more preferably about 0.8 to 1.2 equivalents, per equivalent of epoxy resin system (A). If the amount of component (B) is less than 0.5 equivalents, the epoxy resin composition is likely to be incompletely cured. On the other hand, if the amount exceeds 1.5 equivalents, the cured product is likely to have lower toughness than that of the present invention.

[0046] Particularly preferably, the acid anhydride curing agent (B) can be incorporated into the conductive epoxy resin composition in an amount of 3% to 15% by weight, preferably 3.5% to 10% by weight, based on the total weight of the composition.

[0047] [(C) Solvent] In a preferred embodiment, the conductive epoxy resin composition may contain at least one solvent (C) that disperses the epoxy resin system (A) and the conductive filler (D) in order to reduce the viscosity of the conductive epoxy resin composition.

[0048] Most conductive fillers, such as silver fillers, are commercially available with an organic coating to prevent agglomeration. The solvent acts to dissolve or displace the organic material from the surface of the silver filler. The solvent must have an effective polarity balance to remove the coating and keep the conductive filler dispersed in the solvent until it is dispensed and cured. Typical organic materials used by silver filler manufacturers include stearic acid, isosteric acid, lauric acid, decanoic acid, oleic acid, palmitic acid, or fatty acids neutralized with amines, such as imidazole. An effective solvent is one that removes these and other such lubricants from the surface of the silver filler.

[0049] The type of solvent is not particularly limited as long as it has a flash point higher than 70° C., preferably higher than 90° C. The solvent may be selected from the group consisting of 2-(2-ethoxy-ethoxy)-ethyl acetate, propylene glycol monoethyl ether, butyl ethoxyethyl acetate, propylene carbonate, cyclooctenone, cycloheptanone, cyclohexanone, linear or branched alkanes, tripropylene glycol methyl ether, dipropylene glycol monomethyl ether, and mixtures thereof.

[0050] Commercially available products can be used in the present invention, examples of which include diisobutyl adipate available from Sinopharm Chemical Reagent Co., Ltd., 2-(2-butoxyethoxy)ethyl acetate available from BASF, and diethylene glycol monoethyl ether available from SIGMA-ALDRICH.

[0051] Particularly preferably, the solvent (C) can be incorporated into the conductive epoxy resin composition in an amount of 0.5 to 20% by weight, preferably 1 to 10% by weight, based on the total weight of the composition.

[0052] [(D) Conductive filler] The conductive epoxy resin composition of the present invention contains at least one conductive filler selected from silver, copper, boron nitride, alumina, gold, nickel, a silver-containing alloy, a copper-containing alloy, a nickel-containing alloy, and combinations thereof. From the viewpoint of cost, silver, copper, boron nitride, or alumina is preferably used as the conductive filler in the present invention.

[0053] In a preferred embodiment, the conductive filler has a D of 0.5 to 6.0 μm, preferably 0.8 to 5.0 μm, more preferably 1.0 to 5.0 μm, more preferably 1.1 to 1.4 μm, and even more preferably 1.1 to 3.0 μm. 50 The silver filler may be a silver filler having a particle size within the above range. When the particle size of the silver filler is within the above range, the filler disperses well in the resin composition, improving the storage stability of the resin composition and providing a uniform bonding strength. Here, the "D" of the silver filler 50 The "particle size" refers to the median size in a volume-based particle size distribution curve obtained by measurement using a laser diffraction particle size analyzer.

[0054] In a preferred embodiment, the silver particles used in the conductive epoxy resin composition include flake-shaped particles. Fillers with such shapes have a high contact area between fillers, thereby reducing voids in the cured product. The shape of the silver particles was determined by scanning electron microscope (SEM) observation, and a Philips XL30 can be used as the SEM observation device. Examples of flake particles include particles with shapes known as plate-like, dish-like, scale-like, and flake-like shapes. When flake silver particles come into contact with each other, the contact area is larger than when granular silver particles come into contact with each other. Therefore, when a conductive epoxy resin composition containing flake silver particles is heat-cured, the silver particles become denser, which likely results in improved thermal and electrical conductivity of the cured product of the conductive epoxy resin composition, as well as improved adhesion strength to the surface of a base metal.

[0055] In a preferred embodiment, the conductive filler has a density of 2 to 15 g / cm 3, preferably 3 to 7.5 g / cm 3 The silver filler may have a tap density of 0.1 to 0.5.

[0056] In a preferred embodiment, the silver filler used in the present invention can be produced by known methods such as reduction, milling, electrolysis, atomization, or heat treatment.

[0057] In some embodiments, the surface of the silver filler may be coated with an organic material.

[0058] Here, the state in which the silver filler is "coated with an organic substance" includes a state in which the silver filler is dispersed in an organic solvent, and the organic solvent adheres to the surface of the silver filler.

[0059] Examples of organic substances that coat the silver filler include hydrophilic organic compounds, such as alkyl alcohols having 1 to 5 carbon atoms, alkanethiols having 1 to 5 carbon atoms, alkanepolyols having 1 to 5 carbon atoms, or lower fatty acids having 1 to 5 carbon atoms; and hydrophobic organic compounds, such as higher fatty acids having 15 or more carbon atoms and derivatives thereof, medium-chain fatty acids having 6 to 14 carbon atoms and derivatives thereof, alkyl alcohols having 6 or more carbon atoms, alkylamines having 16 or more carbon atoms, or alkanethiols having 6 or more carbon atoms.

[0060] Examples of higher fatty acids include long-chain saturated fatty acids such as pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, 12-hydroxyoctadecanoic acid, eicosanoic acid, docosanoic acid, tetracosanoic acid, hexacosanoic acid (seric acid), or octacosanoic acid; branched saturated fatty acids such as 2-pentylnonanoic acid, 2-hexyldecanoic acid, 2-heptyldodecanoic acid, or isostearic acid; and unsaturated fatty acids such as palmitoleic acid, oleic acid, isooleic acid, elaidic acid, linoleic acid, linolenic acid, ricinoleic acid, gadoleic acid, erucic acid, and selacholeic acid.

[0061] Examples of intermediate fatty acids include straight-chain saturated fatty acids such as hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, and tetradecanoic acid; branched-chain saturated fatty acids such as isohexanoic acid, isoheptanoic acid, 2-ethylhexanoic acid, isooctanoic acid, isononanoic acid, 2-propylheptanoic acid, isodecanoic acid, isoundecanoic acid, 2-butyloctanoic acid, isododecanoic acid, and isotridecanoic acid; and unsaturated fatty acids such as 10-undecenoic acid.

[0062] Examples of methods for producing a silver filler whose surface is coated with an organic substance include, but are not limited to, a method for producing a silver filler by a reduction method in the presence of an organic solvent. Specifically, the silver filler can be obtained by mixing a silver carboxylate and a primary amine, and precipitating a conductive filler using a reducing agent in the presence of an organic solvent.

[0063] Commercially available silver fillers can be used as the conductive filler in the present invention, examples of which include FA-SAB-238 available from DOWA Hi-Tech Co., Ltd. and EA0295 available from METALOR.

[0064] By coating the surface of the silver filler with an organic substance, aggregation of the silver filler in the adhesive composition can be further prevented or reduced.

[0065] In some embodiments, the silver filler can be used alone or in combination of two or more. Combining fillers of different shapes or sizes can reduce the porosity of the cured product. Examples of combinations include, but are not limited to, a mixture of flake silver filler and approximately spherical silver filler having a smaller central particle size than the flake silver filler.

[0066] Particularly preferably, the conductive filler (D) may be incorporated into the conductive epoxy resin composition in an amount of 65% to 95% by weight, preferably 70% to 95% by weight, based on the total weight of the composition.

[0067] [(E) Catalyst] In some embodiments, a catalyst may be added to speed up the curing process or to lower the temperature of the thermal latent cure.

[0068] Various thermal curing catalysts known in the art can be used in the present invention, including phenylurea, boron trichloride amine complex, imidazole, aliphatic bisurea, phenol, resorcinol, and combinations thereof. In a preferred embodiment, the catalyst effective for the present composition is imidazole. Imidazole is a heterocyclic compound containing nitrogen atoms at the 1 and 3 positions of a five-membered ring. Specific examples of imidazole catalysts include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-phenylimidazole, 2-ethyl-4-methylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 1-cyanoethyl-2-ethyl-4,5-methylimidazole, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, and 2,4-diamino-6-[2'-methylimidazolyl(1')]ethyl-s-triazine isocyanuric acid addition product dehydrate.

[0069] Commercially available examples of imidazole catalysts are Curezol 2MA-OK or Curezol 2PHZ-S available from Air Products. A commercially available example of a latent polyamine is available from Asahi Kasei as HXA 3932HP.

[0070] Particularly preferably, the catalyst (E) may be incorporated into the conductive epoxy resin composition in an amount of 0.1% to 5% by weight, preferably 0.5% to 3% by weight, based on the total weight of the composition.

[0071] According to the present invention, a conductive epoxy resin composition comprising, based on the total weight of the composition, the following is preferred: at least one epoxy resin (A1) having 1 to 15% by weight, preferably 3 to 10% by weight, of at least two glycidyloxy-containing aromatic groups bonded to one another by a divalent endocyclic hydrocarbon group or an aryl group and, optionally, a C1-C6 alkylene group, 0.2 to 5.0 wt. %, preferably 0.5 to 3 wt. %, more preferably 0.75 to 2.25 wt. % of at least one resorcinol diglycidyl ether resin (A2), 3% to 15% by weight, preferably 3.5% to 10% by weight, of at least one acid anhydride hardener (B); 0.5 to 20% by weight, preferably 1 to 10% by weight, of at least one solvent (C); 65% to 95% by weight, preferably 70% to 95% by weight, of at least one conductive filler (D); and 0.1% to 5% by weight, preferably 0.5 to 3% by weight, of at least one catalyst (E).

[0072] [Additives] Other commonly used additives may be further added to the conductive epoxy resin composition of the present invention, examples of which include toughening agents, fluxing agents, peroxides, flow additives, adhesion promoters, rheology modifiers, and mixtures thereof.

[0073] In some embodiments, the conductive epoxy resin composition may include a toughening agent to toughen the epoxy resin, such as a liquid butadiene rubber, which may comprise a homopolymer or copolymer containing repeat units derived from butadiene or isobutadiene, or a copolymer of butadiene or isobutadiene with an acrylate and / or acrylonitrile, such as liquid butadiene acrylonitrile rubber.

[0074] In some embodiments, the liquid butadiene rubber used as a toughening agent of the present invention may contain reactive end groups, such as amino-terminated liquid nitrile rubber (ATBN) or carboxylate-terminated liquid acrylonitrile rubber (CTBN), or liquid rubbers containing free epoxy or methacrylate end groups.

[0075] The addition of the liquid butadiene rubber used as a toughening agent in the present invention is believed to improve the mechanical strength of the cured adhesive composition at elevated temperatures, particularly temperatures above 90°C, preferably above 180°C, and even more preferably above 250°C.

[0076] Liquid butadiene rubber is commercially available, for example, under the trade name Hycar® manufactured by NOVEON.

[0077] According to the present invention, the additive may be present in an amount of 0.1% to 13% by weight, preferably 0.5% to 3% by weight, based on the total weight of the composition.

[0078] [Method for producing conductive epoxy resin composition] The conductive epoxy resin composition of the present invention can be prepared by mixing at room temperature (A1) at least one epoxy resin having at least two glycidyloxy-containing aromatic groups linked together by a divalent endocyclic hydrocarbon group or aryl group and, optionally, a C1-C6 alkylene group; (A2) at least one resorcinol diglycidyl ether resin present in an amount of 0.2 to 5.0 wt. % based on the total weight of the composition; (B) at least one acid anhydride curing agent; (C) optionally, at least one solvent; (D) at least one conductive filler; (E) optionally, at least one catalyst; and, if present, other additives. The method for preparing the conductive epoxy resin composition is not particularly limited, as long as a composition containing the above components is obtained in which the components are uniformly mixed.

[0079] [Cured product and semiconductor device] In another embodiment of the present invention, there is also provided a cured product of the conductive epoxy resin composition of the present invention.

[0080] In a preferred embodiment, the curing temperature of the conductive epoxy resin composition is 120°C to 200°C, preferably 150°C to 180°C.

[0081] The conductive epoxy resin composition of the present invention can be used for joining electronic components to circuits, for example, as a die attacher for joining a semiconductor element to another semiconductor element, and / or as a die attacher for joining a semiconductor element to a support member on which the semiconductor element is mounted.

[0082] In a preferred embodiment, the cured conductive epoxy resin composition has a bond strength of more than 10 MPa at room temperature and more than 1.3 MPa at 260°C, where the test materials are bare silicon die and copper lead frame.

[0083] In an additional aspect of the present invention, there is provided a semiconductor device comprising a cured product of the conductive epoxy resin composition of the present invention.

[0084] A semiconductor device containing a cured product of the conductive epoxy resin composition of the present invention has excellent adhesive strength at a high temperature of 260°C.

[0085] In yet another aspect of the present invention, there is provided the use of the conductive epoxy resin composition of the present invention and a cured product of the conductive epoxy resin composition in the manufacture of semiconductor packages or microelectronic devices. [Example]

[0086] The following examples are intended to aid those skilled in the art in better understanding and practicing the present invention. The scope of the present invention is not limited by the examples, but is defined by the appended claims. Unless otherwise specified, all parts and percentages are by weight.

[0087] Raw materials: DDSA is a liquid mixture of several isomeric alkenyl succinic anhydrides available from Milliken Chemicals.

[0088] XD-1000 is an epoxy resin having at least two glycidyloxy-containing aromatic groups bonded together by a divalent endocyclic hydrocarbon group, available from Nippon.

[0089] ERISYS RDGE is a resorcinol diglycidyl ether resin available from CVC Specialties.

[0090] jER™ 828US is a bisphenol A liquid epoxy resin available from Mitsubishi Chemical.

[0091] ZX1059 is a bisphenol F type epoxy resin available from TOHTO Chemical Industry Co., Ltd.

[0092] Ras-1 is an epoxy resin containing greater than 50% by weight of 2,6-diglycidylphenyl glycidyl ether, available from Henkel.

[0093] Epiclon® N-730 is a multifunctional, phenolic novolac epoxy resin available from DIC Corporation.

[0094] Denacol® EX-191P is a low chlorine monofunctional aromatic epoxy compound based on glycidyl benzoate available from Nagase ChemteX.

[0095] Araldite® MY 0510 is a triglycidylated para-amino-phenol available from Huntsman.

[0096] ERISYS™ GA 240 is a tetrafunctional epoxy resin based on metaxylenediamine, available from CVC Specialties.

[0097] Epalloy™ 5200 is a cycloaliphatic glycidyl ester available from CVC Specialties.

[0098] ERISYS™ GE 22 is an epoxidized cyclohexanedimethanol available from CVC Specialties.

[0099] EPALLOY® 5000 is a diepoxide of a cycloaliphatic alcohol, hydrogenated bisphenol A, available from CVC Specialties.

[0100] ERISYS™ GE 60 is an aliphatic multifunctional epoxy resin available from CVC Specialties.

[0101] ERISYS™ GE 40 is an epoxidized pentaerythritol available from CVC Specialties.

[0102] ERISYS™ GE 30 is a low viscosity trimethylolpropane triglycidyl ether grade. It is a highly epoxy-functionalized resin available from CVC Specialties.

[0103] CELLOXIDE 2021P is a cycloaliphatic epoxide available from DAICEL CORPORATION.

[0104] CELLOXIDE 2081 is a cycloaliphatic epoxide available from DAICEL CORPORATION.

[0105] ETERNACOLL® OXBP is a biphenyl bisoxetane available from UBE INDUSTRIES, LTD.

[0106] 2-(2-butoxyethoxy)ethyl acetate is available from SIGMA-ALDRICH.

[0107] HYCAR® CTBN 1300X8 is a carboxyl-terminated butadiene-acrylonitrile copolymer used as a toughening agent, available from NOVEON.

[0108] 2MAOK is an imidazole catalyst available from Air Products.

[0109] EA0295 is a silver filler available from METALOR.

[0110] Silquest® A-186 is an adhesion promoter available from GE Silicones.

[0111] jER Cure® YH307 is a modified acid anhydride available from Milliken Chemicals.

[0112] Epiclon B-570-H is 3-methyl-tetrahydro-phthalic anhydride available from DIC Europe GmbH.

[0113] RIKACID MH700 is 4-methylhexahydrophthalic anhydride available from New Japan Chemical Co., Ltd.

[0114] NC-3000-L is a glycidyloxy group-containing biphenyl type epoxy resin available from Nippon.

[0115] NC-3500 is a glycidyloxy group-containing biphenyl type epoxy resin available from Nippon.

[0116] HXA 3932HP is a latent hardener available from AsahiKASEI.

[0117] Manufacturing method: In the following examples, the compositions were prepared by the following steps: 1. Epoxy resin (A1) and RDGE (A2) (or other epoxy resins substituted for RDGE in comparative examples), solvent (C) (if present), and adhesion promoter (if present) were first mixed at 60°C for 1 hour, and then further mixed at room temperature at 2000 r / min using a speed mixer for 2 minutes; 2. Then, catalyst (E) (if present) was added and mixed using a speed mixer at 2000 r / min for 2 minutes; 3. The reinforcer (if present) was added and mixed using a speed mixer at 2000 r / min for 2 minutes; 4. Acid anhydride (B) was added and mixed for 2 minutes at 2000 r / min using a speed mixer; and 5. The conductive filler (D) was added, and the mixture was mixed for 2 minutes at 1000 r / min using a speed mixer, followed by degassing.

[0118] Test Method: Die shear strength: The room temperature die shear strength (RTDSS) was measured at 25°C using a DAGE4000. 2 The coating was applied to a bare silicon die and used on a commercial type copper lead frame (CDA151) used in the semiconductor industry. The samples were cured at 5°C / min to 175°C for 1 hour under N2 atmosphere. No pressure was used. Each sample was tested eight times under the same conditions, and the average die shear strength was calculated and recorded using a simple average method to eliminate errors. The average RTDSS target was 10 kg / mm 2 That was all.

[0119] High temperature die shear strength (HTDSS) was measured at 260°C using a DAGE4000 equipped with a heater adapter plate capable of reaching 260°C. 2The coating was applied to bare silicon dies and used on commercial-type copper lead frames (CDA151) used in the semiconductor industry. Samples were cured at 5°C / min to 175°C for 1 hour under N2 atmosphere. No pressure was used. Each sample was tested eight times under the same conditions, and the average die shear strength was calculated and recorded using a simple average method to eliminate errors. The average HTDSS target was 1.3 Kg / mm 2 That was all.

[0120] Example 1 of the present invention and Comparative Examples 1 to 16 In this series of examples, one conductive epoxy resin composition containing RDGE according to the present invention (Example 1) and sixteen compositions (Comparative Examples 1-16) in which RDGE was replaced with other epoxy resins were prepared based on the weight percentages specified in the table below. The RTDSS and HTDSS of the samples were tested.

[0121] [Table 1]

[0122] Table 1 showed that the compositions containing RDGE had higher average die shear strength on copper lead frames at both room temperature and elevated temperatures than the compositions containing other epoxy resins.

[0123] Examples 2 to 4 of the present invention and Comparative Examples 17 and 18 In this series of experimental examples, conductive epoxy resin compositions using the epoxy resin (A1) of the present invention (Examples 2 to 4) and conductive epoxy resin compositions using other epoxy resins (Comparative Examples 17 to 18) were prepared based on the weight percentages specified in the table below. The RTDSS and HTDSS of the samples were tested.

[0124] [Table 2]

[0125] The results in Table 2 showed that the combination of the RDGE of the present invention and the epoxy resin (A1) can improve both the RTDSS and the HTDSS, but adding RDGE to epoxy resins other than A1 is not effective in improving the RTDSS or the HTDSS.

[0126] Examples 5 to 8 of the present invention In this series of examples, conductive epoxy resin compositions of the present invention (Examples 5 to 8) with different RDGE contents were prepared based on the weight percentages specified in the table below. The RTDSS and HTDSS of the samples were tested.

[0127] [Table 3]

[0128] The results in Table 3 showed that the compositions of the present invention containing a given amount of RDGE can improve both RTDSS and HTDSS.

[0129] Examples 9 to 12 of the present invention In this series of examples, conductive epoxy resin compositions of the present invention (Examples 9-12) using different anhydride curing agents were prepared based on the weight percentages specified in the table below. The RTDSS and HTDSS of the samples were tested.

[0130] [Table 4]

[0131] The above results shown in Table 4 demonstrated that the compositions of the present invention containing a given amount of RDGE can improve both RTDSS and HTDSS.

[0132] While several preferred embodiments have been described, many modifications and variations thereto are possible in light of the above teachings, and it is therefore to be understood that the invention may be practiced otherwise than as specifically described without departing from the scope of the appended claims.

Claims

1. (A) at least one epoxy resin system comprising: (A1) Divalent endocyclic hydrocarbon group or structural formula X4 to X9: 【Chemistry 1】 [wherein each R' independently represents a C 1 -C 6 alkylene group; * represents a bonding site to the glycidyloxy group-containing aromatic group] at least one epoxy resin having at least two glycidyloxy-containing aromatic groups bonded to each other by a group selected from the group consisting of: Here, the divalent endocyclic hydrocarbon group is a group represented by the structural formulas X1 to X3: 【Chemistry 2】 [wherein, there may be multiple R per ring, and each R independently represents a hydrogen atom or a methyl group; * represents a bonding site for bonding to the glycidyloxy group-containing aromatic group] is a group selected from the group consisting of: (A2) at least one resorcinol diglycidyl ether resin, present in an amount of 0.2 to 5.0 wt. %, based on the total weight of the composition; wherein the weight ratio of the resorcinol diglycidyl ether resin (A2) to the epoxy resin (A1) is 1:4 to 1:20; (B) at least one acid anhydride curing agent; (C) optionally, at least one solvent; (D) at least one conductive filler; and (E) optionally, at least one catalyst 1. A conductive epoxy resin composition comprising:

2. 2. The composition of claim 1, wherein the glycidyloxy-containing aromatic group is selected from a monofunctional glycidyloxy-containing phenol, a polyfunctional glycidyloxy-containing phenol, a monofunctional glycidyloxy-containing naphthalene group, a polyfunctional glycidyloxy-containing naphthalene group, and combinations thereof.

3. 3. The composition according to claim 1, wherein the epoxy resin (A1) is selected from a glycidyloxy group-containing biphenyl-type epoxy resin, a glycidyloxy group-containing naphthalene-type epoxy resin, a glycidyloxy group-containing epoxy resin having a divalent endocyclic hydrocarbon group, and a combination thereof.

4. The composition of any one of claims 1 to 3, wherein the resorcinol diglycidyl ether resin (A2) is present in an amount of 0.5 to 3.0 wt%, based on the total weight of the composition.

5. The composition of any one of claims 1 to 4, wherein the acid anhydride curing agent (B) is selected from phthalic anhydride, maleic anhydride, trimellitic anhydride, pyromellitic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, nadic methyl anhydride, nadic anhydride, glutaric anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, and combinations thereof.

6. The composition of any one of claims 1 to 5, wherein the conductive filler (D) is selected from silver, copper, boron nitride, alumina, gold, nickel, a silver-containing alloy, a copper-containing alloy, a nickel-containing alloy, and combinations thereof.

7. The composition of any one of claims 1 to 6, wherein the catalyst (E) is selected from phenylurea, boron trichloride amine complex, imidazole, aliphatic bis-urea, phenol, resorcinol, and combinations thereof.

8. 8. The composition of any of claims 1 to 7, wherein the composition further comprises an additive selected from toughening agents, fluxing agents, peroxides, flow additives, adhesion promoters, rheology modifiers, and combinations thereof.

9. The composition of any of claims 1 to 8, wherein component (A1) is present in an amount of 1 to 15 wt%, based on the total weight of the composition.

10. The composition of any of claims 1 to 9, wherein component (B) is present in an amount of 3% to 15% by weight, based on the total weight of the composition.

11. The composition of any of claims 1 to 10, wherein component (C) is present in an amount of 0.5 to 20 wt %, based on the total weight of the composition.

12. The composition of any of claims 1 to 11, wherein component (D) is present in an amount of 65% to 95% by weight, based on the total weight of the composition.

13. A cured product of the conductive epoxy resin composition according to any one of claims 1 to 12.

14. A semiconductor device comprising a cured product of the conductive epoxy resin composition according to claim 13.

15. Use of the conductive epoxy resin composition according to any one of claims 1 to 12 or a cured product of the conductive epoxy resin composition according to claim 13 in the manufacture of a semiconductor package or a microelectronic device.

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