Conductive epoxy resin composition for copper bonding

Abstract

This invention relates to a conductive epoxy resin composition, particularly for bonding copper substrates, and to a cured product, its use, and a semiconductor device comprising the cured product.

Description

Technical Field

[0001] This invention relates to a conductive epoxy resin composition, specifically for bonding copper substrates, and to a cured product, its use, and a semiconductor device comprising the cured product. Prior Technology

[0002] Conductive epoxy 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 or other substrates. Importantly, cured adhesives demonstrate high adhesion, high thermal conductivity, high moisture resistance, good temperature stability, and good reliability.

[0003] Conventional conductive epoxy adhesives typically consist of conductive fillers, epoxy resin, and a curing agent. However, epoxy resins can be brittle, and other resins have been evaluated and used to provide flexibility, hydrophobicity, and other properties to grain-bonding adhesives. Specifically, conductive epoxy adhesives do not exhibit strong adhesion to copper substrates, especially at high temperatures (e.g., above 260°C).

[0004] Therefore, it is still necessary to develop conductive epoxy adhesives that can bond copper substrates with good adhesion at high temperatures (especially above 260°C). Summary of the Invention

[0005] After in-depth research, the inventors have discovered that the above problem can be solved by a conductive epoxy resin composition containing the following: (A) At least one epoxy resin system comprising: (A1) at least one epoxy resin having at least two aromatic groups containing glycidyl oxy groups bonded together by divalent intracyclic hydrocarbon groups or aryl groups, and C1 to C6 alkyl groups as desired; 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) At least one solvent, if necessary; (D) At least one conductive filler; and (E) At least one catalyst, if necessary.

[0006] In another embodiment of the invention, a cured product of the conductive epoxy resin composition according to the invention is provided.

[0007] In another embodiment of the present invention, a semiconductor device is provided comprising a cured product containing a conductive adhesive according to the present invention.

[0008] In yet another embodiment of the invention, a conductive epoxy resin composition and a cured product of the conductive epoxy resin composition are provided for use in the manufacture of semiconductor packages or microelectronic devices. Implementation

[0009] Those skilled in the art will understand that the present invention is merely a description of illustrative embodiments and is not intended to limit the broader scope of the invention. Unless expressly indicated otherwise, the various aspects thus described may be combined with any other one or more aspects. Specifically, any feature indicated as preferred or advantageous may be combined with any other one or more features indicated as preferred or advantageous.

[0010] Unless otherwise specified, the terminology used in this invention shall be interpreted in accordance with the following definitions.

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

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

[0013] Unless otherwise specified, the list of numerical endpoints includes all numbers and fractions that fall into an individual range, and the endpoint of the list.

[0014] All references listed in this specification are incorporated herein by full citation.

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

[0016] This invention relates to a conductive epoxy resin composition comprising: (A) At least one epoxy resin system comprising: (A1) at least one epoxy resin having at least two aromatic groups containing glycidyl oxy groups bonded together by divalent intracyclic hydrocarbon groups or aryl groups, and C1 to C6 alkyl groups as desired; 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) At least one solvent, if necessary; (D) At least one conductive filler; and (E) At least one catalyst, if necessary.

[0017] [] [(A)] [Epoxy Resin System] [] According to the present invention, a significant feature is that the conductive epoxy resin composition contains an epoxy resin system (A) comprising (A1) at least one epoxy resin having at least two aromatic groups containing glycidyl oxy groups bonded together by divalent intracyclic hydrocarbon groups or aryl groups, and C1 to C6 alkyl groups as desired; and (A2) at least one resorcinol diglycidyl ether resin present in an amount of 0.2 to 5.0% by weight based on the total weight of the composition, which significantly improves the adhesion to the bonded copper substrate at high temperatures.

[0018] (A1) Epoxy resin According to the present invention, the epoxy resin (A1) has at least two aromatic groups containing glycidyl oxy groups bonded together by divalent intracyclic hydrocarbon groups or aryl groups, and C1 to C6 alkyl groups as desired.

[0019] Aromatic groups containing glycidyloxy groups can have various structures, including (but not limited to) phenols containing monofunctional glycidyloxy groups, phenols containing polyfunctional glycidyloxy groups, naphthyl groups containing monofunctional glycidyloxy groups, naphthyl groups containing polyfunctional glycidyloxy groups, and combinations thereof. Specific examples can be represented by the following structural formulas Ep1 to Ep9: In this invention, the aromatic group containing glycidyloxy group is not limited to the above structural formulas Ep1 to Ep9. In other embodiments, the aromatic group containing glycidyloxy group may be a phenol or naphthyl group containing triglycidyl or tetraglycidyl groups.

[0020] In the structures described above, when two or more bonds connecting to other structural sites are located on the naphthyl group, these bonds may be located on the same or different atomic nuclei.

[0021] In this invention, the epoxy resin (A1) has at least two aromatic groups containing glycidyloxy groups bonded together by divalent intracyclic hydrocarbon groups or aryl groups, and C1 to C6 alkyl groups as desired. This bonding can be any desired combination of bonding forms.

[0022] In a preferred embodiment, the epoxy resin (A1) has at least two aromatic groups containing glycidyl oxy groups, which are formed by the bonding of divalent intracyclic hydrocarbon groups. Examples of such divalent intracyclic hydrocarbon groups can be represented by the following structural formulas X1 to X3: Each ring may contain multiple Rs, each R independently representing a hydrogen atom or a methyl group; and * represents a binding site attached to an aromatic group containing a glycidoxy group.

[0023] In some embodiments, the epoxy resin (A1) has at least two aromatic groups containing glycidyloxy groups bonded together by aryl groups. The term "aryl" herein refers to a polyunsaturated aromatic substituent that may be monocyclic, fused together, or covalently linked polycyclic (preferably 1 to 3 rings). Examples of aryl groups include (but are not limited to) phenyl, tolyl, xylyl, and 4-biphenyl.

[0024] In a preferred embodiment, the epoxy resin (A1) has at least two aromatic groups containing glycidyloxy groups bonded together by aryl groups and C1 to C6 alkyl groups. Examples of C1 to C6 enyl alkyl groups include -CH2-, -CH2CH2-, -CH2CH2CH2-, -CH(CH3)CH2-, -CH(C2H5)CH2-, -CH2CH2CH2CH2-, -C(CH3)2CH2-, -CH(CH3)CH2CH2-, -CH2CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -CH2CH2CH2CH2CH2-, -CH(CH3)CH2CH2CH2-, -CH2CH(CH3)CH2CH2-, -C(CH3)2CH2CH2-, -CH2C(CH3)2CH2-, -CH(C2H5)CH2CH2-, -CH2CH(C2H5)CH2-, -CH(CH3)CH(CH3)CH2-, -CH2CH2CH2 CH2 CH2 CH2 -, -CH(CH3 )CH2 CH2 CH2 CH2 -, -CH2 CH(CH3 )CH2 CH2 CH2 -, -CH2 CH2 CH(CH3 )CH2 CH2 -, -C(CH3 )2 CH2 CH2 CH2 -, -CH2 C(CH3 )2 CH2 CH2 -, -CH(CH3 )CH(CH3 )CH2 CH2 -, -CH(CH3 )CH2 CH(CH3 )CH2 -, -CH(CH3 )CH2 CH2 CH(CH3 )-, -CH2 CH(CH3 )CH2 CH(CH3 )-, -CH2 CH(CH3 )CH(CH3 )CH2 -, -CH(C2 H5 )CH2 CH2 CH2 -, and -CH2 CH(C2 H5 )CH2 CH2 -.

[0025] Specific examples of combinations of aryl and C1 to C6 alkyl groups include (but are not limited to) phenylmethyl, 2-methylbiphenyl, 3-methylbiphenyl, 4-methylbiphenyl, 2-methylnaphthyl, 3-methylnaphthyl, and 4-methylnaphthyl, represented by the following structural formulas X4 to X9: R' independently represents a C1 to C6 alkyl group, preferably a C1 to C3 alkyl group, and more preferably a methylene group; and * represents a binding site attached to an aromatic group containing a glycidyloxy group.

[0026] From the viewpoint of providing toughness to the cured product of the composition, structures X1 and X7 are particularly preferred.

[0027] In some embodiments, the epoxy resin (A1) may be selected from biphenyl-type epoxy resin containing glycidyl oxy group, naphthalene-type epoxy resin containing glycidyl oxy group, epoxy resin containing glycidyl oxy group having divalent internal ring hydrocarbon group, and combinations thereof.

[0028] Specific examples of biphenyl-type epoxy resins containing glycidyl oxy groups used in this invention (A1) can be represented by the following structural formulas P1 and P2: P1 Where n can be the average of 1 to 5. P2 Where n can be the average of 1 to 5.

[0029] A specific example of an epoxy resin containing a divalent internal ring hydrocarbon group and containing a glycidyl group, used as an epoxy resin (A1) in this invention, can be represented by the following structural formula P3: P3 Where n can be an average of 1 to 5. In this structure, the phenolic group containing the diglycidyl group can bind to any structural site located on the octahydro-4,7-methylbridged indene.

[0030] Because the present invention has the characteristic chemical structure described above, the aromatic or intracyclic hydrocarbon structure makes it strong and rigid. Therefore, this resin can provide enhanced toughness while maintaining heat resistance.

[0031] In a preferred embodiment, the epoxy resin (A1) preferably has an epoxy equivalent in the range of 180 to 500 g / equivalent, more preferably 200 to 400 g / equivalent.

[0032] In some embodiments, the epoxy resin (A1) can be produced by a production method known in the art, by reacting a phenolic resin with epichlorohydrin.

[0033] Examples of commercially available epoxy resins (A1) include the NC-3000 series (NC-3000 and NC-2000-L) and XD-1000 manufactured by Nippon Kayaku Ltd.

[0034] Particularly preferably, based on the total weight of the composition, 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.

[0035] (A2) Resorcinol diglycidyl ether resin According to the present invention, adding a certain amount of resorcinol diglycidyl ether resin (A2) (i.e., 0.2 to 5.0% by weight, preferably 0.5 to 3.0% by weight, more preferably 0.75 to 2.25% by weight) to the epoxy resin (A1) provided in the present invention, based on the total weight of the composition, can significantly improve the adhesion of the bonded copper substrate.

[0036] Resorcinol diglycidyl ether (RDGE) exhibits excellent oxygen barrier properties, as well as good chemical resistance, flexibility, and adhesion to various substrates. Compared to other epoxy resins, RDGE-based resins offer advantageous conformational encapsulation, improved hydrogen bonding, and inter- and intra-chain interactions within these resins.

[0037] In some embodiments, when the resorcinol diglycidyl ether resin comprises a monomer, the resorcinol exhibits generally low viscosity (e.g., between about 200 and about 500 cps at about 25°C) and generally high reactivity with the epoxy resin. The resorcinol diglycidyl ether resin may exhibit an epoxy equivalent between about 100 g and about 130 g. The resorcinol diglycidyl ether epoxy resin may have the general structure (I) shown below: (I) An example of resorcinol diglycidyl ether resin is ERISYS® RDGE (a purified form of RDGE), which is available from CVC Thermoset Specialties. ERISYS® RDGE has a viscosity of approximately 300 to 500 cps at 25°C and a maximum residual epichlorohydrin content of 10 ppm.

[0038] Particularly preferably, based on the total weight of the composition, the resorcinol diglycidyl ether resin (A2) incorporated into the conductive epoxy resin composition is present in an amount of 0.2 to 5.0% by weight, more preferably 0.5 to 3.0% by weight, and even more preferably 0.75 to 2.25% by weight.

[0039] In a preferred embodiment, the weight ratio of resorcinol diglycidyl ether resin (A2) to epoxy resin (A1) is 1:4 to 1:20, more preferably 1:5 to 1:15, and even more preferably 1:6 to 1:10.

[0040] [] [(B)] [Acid anhydride curing agent] [] According to the present invention, the conductive epoxy resin composition comprises 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).

[0041] Specific examples of anhydride curing agents include phthalic anhydride, maleic anhydride, trimellitic anhydride, pyromellitic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, nadic methyl acid anhydride, nadic anhydride, glutaric anhydride, methylhexahydrophthalic anhydride, and methyltetrahydrophthalic anhydride. These anhydrides can be used alone or in combination.

[0042] Phthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, and similar compounds are preferred.

[0043] There is no particular limitation on the amount of the anhydride curing agent (B) to be used, but it is generally preferred that the anhydride curing agent (B) is in an amount of about 0.5 to 1.5 equivalents per equimolar of epoxy resin system (A), and more preferably about 0.8 to 1.2 equivalents. When the amount of component (B) is less than 0.5 equivalents, the curing of the epoxy resin composition may be incomplete, and when it exceeds 1.5 equivalents, the cured product may not be as robust as the cured product of the present invention.

[0044] Particularly preferably, based on the total weight of the composition, the anhydride curing agent (B) may be incorporated into the conductive epoxy resin composition in an amount of 3% to 15% by weight, preferably 3.5% to 10% by weight.

[0045] [] [(C)] [solvent] [] In a preferred embodiment, the conductive epoxy resin composition may include at least one solvent (C) to disperse the epoxy resin system (A) and the conductive filler (D) in order to reduce the viscosity of the conductive epoxy resin composition.

[0046] Most commercially available conductive fillers (e.g., silver fillers) have an organic coating to prevent agglomeration. A solvent plays a role in dissolving or displacing the organic material on the surface of the silver filler. This solvent must have a polarity balance to effectively remove the coating and allow the conductive filler to remain dispersed in the solvent until it is dispensed and cured. Typical organic materials used by silver filler manufacturers include stearic acid, isostearic 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.

[0047] There are no restrictions on the type of solvent, as long as it has a flash point greater than 70°C, preferably greater than 90°C. The solvent may be selected from the group consisting of: ethyl 2-(2-ethoxy-ethoxy)-ethyl acetate, propylene glycol monoethyl ether, butyl ethoxyethyl acetate, propylene carbonate, cyclooctenone, cycloheptanone, cyclohexanone, straight-chain or branched-chain alkanes, tripropylene glycol methyl ether, dipropylene glycol monomethyl ether, and mixtures thereof.

[0048] Commercially available products may be used in this invention. Examples include diisobutyl adipate, which is available from Sinopharm Chemical Reagent Ltd., ethyl 2-(2-butoxyethoxy)acetate, which is available from BASF, and diethylene glycol monoethyl ether, which is available from SIGMA-ALDRICH.

[0049] Particularly preferably, based on the total weight of the composition, the solvent (C) may be incorporated into the conductive epoxy resin composition in an amount of 0.5 to 20% by weight, preferably 1 to 10% by weight.

[0050] [] [(D)] [Conductive filler] [] The conductive epoxy resin composition according to the present invention comprises at least one conductive filler selected from the following: silver, copper, boron nitride, aluminum oxide, gold, nickel, silver-containing alloys, copper-containing alloys, nickel-containing alloys, and combinations thereof. For cost reasons, silver, copper, boron nitride, or aluminum oxide is preferably used as the conductive filler in the present invention.

[0051] In a preferred embodiment, the conductive filler may be a silver filler having a D50 particle size of 0.5 to 6.0 μm, more 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. When the particle size of the silver filler is within the above range, the filler is better dispersed in the resin composition, which can improve the storage stability of the resin composition and provide uniform bonding strength. Hereinafter, the "D50 particle size" of the silver filler refers to the median diameter in a volume-based particle size distribution curve obtained by laser diffraction particle size analyzer.

[0052] In a preferred embodiment, the silver particles used in the conductive epoxy resin composition comprise particles in the shape of flakes. Fillers with this shape have a high contact area between them, which reduces voids in the cured product. The shape of the silver particles is for observation and analysis using a scanning electron microscope (SEM), and the Philips XL30 can be used as the SEM observation device. Examples of flake particles include particles with shapes described as plate-like, disc-like, scale-like, and plate-like. Compared to the case where granular silver particles are in contact with each other, the contact area is increased when flake silver particles are in contact with each other. Therefore, if the conductive epoxy resin composition containing flake silver particles is thermocured, the density of the silver particles will increase, and thus it is presumed that the cured product of the conductive epoxy resin composition not only has increased thermal and electrical conductivity but also improved adhesion strength to the surface of the substrate metal.

[0053] In a preferred embodiment, the conductive filler may be a silver filler having a knock-tightness of 2 to 15 g / cm3, preferably 3 to 7.5 g / cm3.

[0054] In a preferred embodiment, the silver filler used in this invention can be manufactured by known methods (such as reduction, milling, electrolysis, atomization or heat treatment).

[0055] In some embodiments, the surface of the silver filler may be coated with an organic substance.

[0056] In this article, the condition of silver filler being "coated with organic substances" includes the condition in which the organic solvent adheres to the surface of the silver filler by dispersing the silver filler in an organic solvent.

[0057] Examples of organic materials used for coating silver fillers may include hydrophilic organic compounds, such as alkyl alcohols having 1 to 5 carbon atoms, alkyl thiols having 1 to 5 carbon atoms, and alkane polyols having 1 to 5 carbon atoms, or low-carbon fatty acids having 1 to 5 carbon atoms; and hydrophobic organic compounds, such as high-carbon fatty acids having 15 or more carbon atoms and their derivatives, medium-carbon fatty acids having 6 to 14 carbon atoms and their derivatives, alkyl alcohols having 6 or more carbon atoms, alkylamines having 16 or more carbon atoms, or alkyl thiols having 6 or more carbon atoms.

[0058] Examples of high-carbon-number fatty acids include straight-chain saturated fatty acids such as pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, 12-hydroxyoctadecanoic acid, eicosanoic acid, docosanoic acid, icosanoic acid (waxic acid), or octadecanoic acid; branched-chain 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, isoleic acid, transoleic acid, linoleic acid, linolenic acid, ricinoleic acid, thiocyanate, erucic acid, and squalane.

[0059] Examples of medium-carbon number 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, or tetradecanoic acid; branched-chain saturated fatty acids such as isohexanoic acid, isohexanoic acid, 2-hexylhexanoic acid, isooctanoic acid, isononanoic acid, 2-propylheptanoic acid, isodecanic acid, isoundecanoic acid, 2-butyloctanoic acid, isodecanic acid, and isotriadecanoic acid; and unsaturated fatty acids such as 10-undecenoic acid.

[0060] Examples of methods for manufacturing silver fillers with organic coatings include (but are not particularly limited to) methods for manufacturing silver fillers by reduction in the presence of organic solvents. Specifically, the silver filler can be obtained by mixing silver carboxylate salts with primary amines and depositing conductive fillers using a reducing agent in the presence of an organic solvent.

[0061] Commercially available silver fillers can be used as conductive fillers in this invention. Examples include FA-SAB-238, available from Dowa Hightech, and EA0295, available from Metalor.

[0062] When the surface of the silver filler is coated with an organic substance, the aggregation of the silver filler in the adhesive composition can be further prevented or reduced.

[0063] In some embodiments, silver fillers may be used alone or in combination with two or more types. Combinations of fillers of different shapes or sizes can reduce the porosity of the cured product. Examples of such combinations include (but are not limited to) mixtures of flake-shaped silver fillers and approximately spherical silver fillers with a central particle diameter smaller than that of the flake-shaped silver filler.

[0064] Particularly preferably, based on the total weight of the composition, 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.

[0065] [] [(E)] [catalyst] [] In some embodiments, a catalyst may be added to accelerate the curing process or reduce the temperature of latent heat curing.

[0066] Various thermosetting catalysts known in this art can be used in this invention, including phenylurea, boron trichloride ammonium complex, imidazole, aliphatic biuret, phenol, resorcinol, and combinations thereof. In a preferred embodiment, the effective catalyst for the composition is imidazole. Imidazole is a heterocyclic compound containing a nitrogen atom at the 1,3-position of a 5-membered ring. Specific examples of imidazole catalysts include 2-methylimidazolium, 2-undecylimidazolium, 2-heptadecylimidazolium, 1,2-dimethylimidazolium, 2-phenylimidazolium, 2-ethyl-4-methylimidazolium, 2-phenyl-4-methylimidazolium, 1-benzyl-2-methylimidazolium, 1-benzyl-2-phenylimidazolium, 2-phenyl-4,5-dihydroxymethylimidazolium, 2-phenyl-4-methyl-5-hydroxymethylimidazolium, 1-cyanoethyl-2-ethyl-4,5-methylimidazolium, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-me-triazine, and dehydrated products of 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-me-triazine isocyanuric acid addition products.

[0067] Commercial examples of imidazole catalysts include Curezol 2MA-OK or Curezol 2PHZ-S, available from Air Products. A potential commercial example of a polyamine is HXA 3932HP, available from AsahiKASEI.

[0068] Particularly preferably, based on the total weight of the composition, 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.

[0069] According to a preferred embodiment of the invention, the conductive epoxy resin composition comprises, based on the total weight of the composition: At least one epoxy resin comprising 1 to 15% by weight, preferably 3 to 10% by weight, having at least two aromatic groups containing glycidyl oxy groups bonded together by divalent intracyclic hydrocarbon groups or aryl groups, and, if desired, C1 to C6 alkyl groups (A1). At least one resorcinol diglycidyl ether resin (A2) is present in an amount of 0.2 to 5.0% by weight, preferably 0.5 to 3% by weight, and even more preferably 0.75 to 2.25% by weight. At least one anhydride curing agent (B) of 3% to 15% by weight, preferably 3.5% to 10% by weight; 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 At least one catalyst (E) of 0.1% to 5% by weight, preferably 0.5% to 3% by weight.

[0070] [] [additive] [] Other commonly used additives that can be further added to the conductive epoxy resin composition of the present invention include toughening agents, fluxes, peroxides, flow additives, adhesion promoters, rheology modifiers, and mixtures thereof.

[0071] In some embodiments, the conductive epoxy resin composition may include a toughening agent (e.g., liquid butadiene rubber) to make the epoxy resin tough. The liquid butadiene rubber may be a homopolymer or copolymer containing repeating units derived from butadiene or isobutadiene, or a copolymer of butadiene or isobutadiene with acrylates and / or acrylonitrile, such as liquid butadiene acrylonitrile rubber.

[0072] In some embodiments, the liquid butadiene rubber used as the toughening agent of the present invention may contain reactive end groups, such as amino-terminated liquid nitrile rubber (ATBN) or carboxylic acid-terminated liquid acrylonitrile rubber (CTBN) or liquid rubber containing free epoxy or methacrylate end groups.

[0073] It is believed that the liquid butadiene rubber modified curing adhesive composition with added toughening agent in this invention has mechanical strength at high temperatures, specifically at temperatures greater than 90°C, preferably greater than 180°C or even more preferably greater than 250°C.

[0074] Liquid butadiene rubber can be purchased, for example, from NOVEON under the trade name Hycar®.

[0075] According to the present invention, the additive may be present in an amount of 0.1% to 13%, preferably 0.5% to 3% by weight, based on the total weight of the composition.

[0076] [] [Method for manufacturing conductive epoxy resin composition] [] The conductive epoxy resin composition according to the present invention can be manufactured by mixing the following at room temperature: (A1) at least one epoxy resin having at least two aromatic groups containing glycidyloxy groups bonded together by divalent intracyclic hydrocarbon groups or aryl groups, and C1 to C6 alkyl groups as desired; (A2) at least one resorcinol diglycidyl ether resin present in an amount of 0.2 to 5.0% by weight based on the total weight of the composition; (B) at least one acid anhydride curing agent; (C) at least one solvent as desired; (D) at least one conductive filler; (E) at least one catalyst as desired; and other additives if present. The method of manufacturing the conductive epoxy resin composition is not particularly limited, as long as a composition in which the components described above are uniformly mixed can be obtained.

[0077] [Curved products and semiconductor devices] [] In another embodiment of the invention, a cured product of the conductive epoxy resin composition according to the invention is provided.

[0078] 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.

[0079] The conductive epoxy resin composition of the present invention can be used in circuits for bonding to electronic components, such as die bonders for bonding semiconductor components and another semiconductor component, and / or die bonders for bonding semiconductor components and support members for mounting the semiconductor components.

[0080] In a preferred embodiment, the cured product of the conductive epoxy resin composition has a bonding strength greater than 10 MPa at room temperature and greater than 1.3 MPa at 260°C, wherein the test materials are bare silicon grains and copper lead frames.

[0081] In another embodiment of the present invention, a semiconductor device comprising a cured product of a conductive epoxy resin composition according to the present invention is provided.

[0082] Semiconductor devices comprising cured products of the conductive epoxy resin composition according to the present invention exhibit excellent adhesion strength at a high temperature of 260°C.

[0083] In yet another embodiment of the invention, the conductive epoxy resin composition according to the invention and the cured product of the conductive epoxy resin composition are provided for use in the manufacture of semiconductor packages or microelectronic devices.

[0084] [] [Example] [] The following examples are intended to help those skilled in the art to better understand and practice this invention. The scope of this invention is not limited by these examples but is defined within the scope of the appended claims. Unless otherwise specified, all parts and percentages are based on weight.

[0085] [] [Raw materials:] [] DDSA is a liquid mixture of several isomeric alkenyl succinic anhydrides available from Millicken Chemicals.

[0086] XD-1000 is an epoxy resin available from Nippon that contains at least two aromatic groups with glycidyl oxy groups bonded together by divalent intracyclic hydrocarbon groups.

[0087] ERISYS RDGE series resorcinol diglycidyl ether resin is available from CVC Specialties.

[0088] jERTM 828US is a bisphenol A liquid epoxy resin available from Mitsubishi Chemical.

[0089] ZX1059 is a bisphenol F type epoxy resin that can be purchased from TOHTO Chemical Industry Co., Ltd.

[0090] Ras-1 is an epoxy resin containing more than 50% by weight of 2,6-diglycidylphenylglycidyl ether, which is available from Henkel.

[0091] Epiclon® N-730 is a multifunctional phenolic resin-based epoxy resin that is available from DIC.

[0092] Denacol® EX-191P is a low-chlorine, monofunctional aromatic epoxy compound based on glycidyl benzoate, available from Nagase ChemteX.

[0093] Araldite® MY 0510 is a triglycidylated p-aminophenol available from Huntsmana.

[0094] ERISYS™ GA 240 series is a tetrafunctional epoxy resin based on m-xylenediamine, available from CVC Specialties.

[0095] Epalloy™ 5200 series is an alicyclic glycidyl ester available from CVC Specialties.

[0096] ERISYS™ GE 22 series epoxidized cyclohexanediethanol is available from CVC Specialties.

[0097] EPALLOY® 5000 series is a biepoxide of alicyclic alcohols, hydrogenated bisphenol A, which is available from CVC Specialties.

[0098] ERISYS™ GE 60 series is an aliphatic multifunctional epoxy resin available from CVC Specialties.

[0099] ERISYS™ GE 40 series is available from CVC Specialties as neopentyl epoxide.

[0100] ERISYS™ GE 30 series low viscosity trimethylolpropane triglycidyl ether grade. It is a high epoxy functional resin available from CVC Specialties.

[0101] CELLOXIDE 2021P is an alicyclic epoxide that can be purchased from DAICL.

[0102] CELLOXIDE 2081 is an alicyclic epoxide that can be purchased from DAICL.

[0103] ETERNACOLL® OXBP is a biphenyl dioxane available from UBE INDUSTRIES, LTD.

[0104] 2-(2-Butoxyethoxy)ethyl acetate is available from SIGMA-ALDRICH.

[0105] HYCAR® CTBN 1300X8 is a carboxyl-terminated butadiene-acrylonitrile copolymer that is available from NOVEON and is used as a toughening agent.

[0106] 2MAOK is an imidazole catalyst that can be purchased from Air Products.

[0107] EA0295 is a silver filler that can be purchased from METALOR.

[0108] Silquest® A-186 is an adhesion promoter from GE Silicones.

[0109] jER Cure® YH307 is a modified acid anhydride available from Millicken Chemicals.

[0110] Epiclon B-570-H is a 3-methyl-tetrahydro-phthalic anhydride available from DIC Europe GmbH.

[0111] RIKACID MH700 is a 4-methylhexahydrophthalic anhydride that can be purchased from New Japan Chemical Co., Ltd.

[0112] NC-3000-L is a biphenyl-type epoxy resin containing glycidyl groups, which is available from Nippon.

[0113] The NC-3500 series is a biphenyl-type epoxy resin containing glycidyl groups, which is available from Nippon.

[0114] HXA 3932HP is a potential hardener that can be purchased from AsahiKASEI.

[0115] [] [Preparation method:] [] In the following examples, the compositions were prepared by the following steps: 1. At 60°C, first mix epoxy resin (A1) and RDGE (A2) (or, in the comparative example, replace RDGE with another epoxy resin), solvent (C) (if present) and adhesion promoter (if present) for 1 hour, and then further mix them at room temperature using a high-speed mixer at 2000 r / min for 2 minutes; 2. Then add catalyst (E) (if present) and mix for 2 minutes at 2000 r / min using a high-speed mixer; 3. Add toughening agent (if present) and mix for 2 minutes at 2000 r / min using a high-speed mixer; 4. Add acid anhydride (B) and mix for 2 minutes at 2000 r / min using a high-speed mixer; and 5. Add conductive filler (D) and mix using a high-speed mixer at 1000 r / min for 2 minutes, then degas.

[0116] [] [Testing Method:] [] [Grain] [Shear strength:] []

[0117] The room temperature grain shear strength (RTDSS) was measured using a DAGE4000 at 25°C. The composition was coated onto 2x2 mm² bare silicon dies and used in commercial copper leadframes (CDA151) for the semiconductor industry. Samples were cured in a N2 atmosphere at 5°C / min up to 175°C for 1 hour. No pressure was applied. Each sample was tested eight times under the same conditions, and the average grain shear strength was calculated and recorded using a simple averaging method to eliminate errors. The target average RTDSS was greater than or equal to 10 kg / mm².

[0118] High-Temperature Grain Shear Strength (HTDSS) was measured using a DAGE4000 with a heater adapter capable of reaching 260°C. The composition was applied to a 2x2 mm² bare silicon die and is used in commercial copper leadframes (CDA151) for the semiconductor industry. Samples were cured in a N2 atmosphere at 5°C / min up to 175°C for 1 hour. No pressure was applied. Each sample was tested eight times under the same conditions, and the average grain shear strength was calculated and recorded using a simple averaging method to eliminate errors. The target average HTDSS was greater than or equal to 1.3 kg / mm².

[0119] [] [Example of the Invention] [1] [and comparative examples] [1] [to]

[16] In this set of examples, based on the weight percentages specified in the table below, a conductive epoxy resin composition containing RDGE according to the present invention (Example 1) and 16 compositions (Compound Examples 1 to 16) in which other epoxy resins replace RDGE were prepared. The RTDSS and HTDSS of the samples were tested. Table 1 Components Example 1 Compound Example 1 Compound Example 2 Compound Example 3 Compound Example 4 Compound Example 5 Compound Example 6 Compound Example 7 Compound Example 8 Compound Example 9 Compound Example 10 Compound Example 11 Compound Example 12 Compound Example 13 Compound Example 14 Compound Example 15 Compound Example 16 DDSA 9.37 9.37 9.37 9.37 9.37 9.37 9.37 9.37 9.37 9.37 9.37 9.37 9.37 9.37 9.37 9.37 9.37 XD-1000 7.62 7.62 7.62 7.62 7.62 7.62 7.62 7.62 7.62 7.62 7.62 7.62 7.62 7.62 7.62 7.62 7.62 ERISYS RDGE 1.25 - - - - - - - - - - - - - - - - jERTM 828US - 1.25 - - - - - - - - - - - - - - - ZX1059 - - 1.25 - - - - - - - - - - - - - - Ras-1 - - - 1.25 - - - - - - - - - - - - - Epiclon® N-730 - - - - 1.25 - - - - - - - - - - - - Denacol® EX-191P - - - - - 1.25 - - - - - - - - - - - Araldite® MY 0510 - - - - - - 1.25 - - - - - - - - - - ERISYS™ GA 240 - - - - - - - 1.25 - - - - - - - - - EpalloyTM 5200 - - - - - - - - 1.25 - - - - - - - - ERISYS™ GE 22 - - - - - - - - 1.25 - - - - - - - EPALLOY® 5000 - - - - - - - - - - 1.25 - - - - - - ERISYS™ GE 60 - - - - - - - - - - - 1.25 - - - - - ERISYS™ GE 40 - - - - - - - - - - - - 1.25 - - - - ERISYS™ GE 30 - - - - - - - - - - - - - 1.25 - - - CELLOXIDE 2021P - - - - - - - - - - - - - - 1.25 - - CELLOXIDE 2081 - - - - - - - - - - - - - - - 1.25 - ETERNACOLL® OXBP - - - - - - - - - - - - - - - - 1.25 2-(2-Butoxyethoxy)ethyl acetate 2.14 2.14 2.14 2.14 2.14 2.14 2.14 2.14 2.14 2.14 2.14 2.14 2.14 2.14 2.14 2.14 2.14 HYCAR CTBN 1300X8 1.87 1.87 1.87 1.87 1.87 1.87 1.87 1.87 1.87 1.87 1.87 1.87 1.87 1.87 1.87 1.87 1.87 2MAOK 1.75 1.75 1.75 1.75 1.75 1.75 1.75 1.75 1.75 1.75 1.75 1.75 1.75 1.75 1.75 1.75 1.75 EA0295 75.0 75.0 75.0 75.0 75.0 75.0 75.0 75.0 75.0 75.0 75.0 75.0 75.0 75.0 75.0 75.0 75.0 SILQUEST® A-186 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 Test Results RTDSS Kg / mm2 14.5 8 7.5 7.2 12.2 5.8 8.9 10.2 6.2 10.2 6.8 9.8 8.7 5.4 7.7 7.3 6.8 HTDSS Kg / mm2 2.2 0.7 0.8 0.8 0.9 0.5 0.7 0.8 0.6 0.8 0.7 0.6 0.5 0.4 0.9 0.7 0.4 Table 1 shows that, at both room temperature and high temperature, the average grain shear strength of compositions containing RDGE on copper lead-frames is higher than that of any composition containing other epoxy resins.

[0120] [] [Example of the Invention] [2] [to] [4] [and comparative examples]

[17] [and]

[18] [] In this set of examples, conductive epoxy resin compositions comprising the epoxy resin (A1) of the present invention (Examples 2 to 4) and other epoxy resins (Compound 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. Table 2 Components Example 2 Example 3 Example 4 compound Example 17 compound Example 18 DDSA 9.37 9.37 9.37 9.37 9.37 XD-1000 7.62 - - - - NC-3000-L - 8.22 - - - NC-3500 - - 6.72 - - ERISYS™ GE 30 - - - 4.57 - Epiclon® N-730 - - - - 5.33 RDGE 1.25 1.25 1.25 1.25 1.25 2-(2-Butoxyethoxy)ethyl acetate 2.14 2.14 2.14 1.00 4.43 HYCAR® CTBN 1300X8 1.87 1.87 1.87 1.87 1.87 2MA-OK 1.75 - - 1.75 1.75 HXA 3932HP - 1.75 1.75 - - EA0295 75.00 74.40 75.90 79.19 75.00 SILQUEST® A-186 1.00 1.00 1.00 1.00 1.00 Test results RTDSS Kg / mm2 14.5 15 15.5 8 12 HTDSS Kg / mm2 2.2 1.6 1.8 0.3 1.1 The results in Table 2 show that the combination of RDGE and epoxy resin (A1) according to the present invention can improve both RTDSS and HTDSS, while adding RDGE to epoxy resin other than A1 has no effect on improving RTDSS or HTDSS.

[0121] [] [Example of the Invention] [5] [to] [8] [] In this set of examples, conductive epoxy resin compositions of the present invention with different contents of RDGE were prepared based on the weight percentages specified in the table below (Examples 5 to 8). The RTDSS and HTDSS of the samples were tested. Table 3 Components Example 5 Example 6 Example 7 Example 8 DDSA 9.37 8.58 10.28 11.18 XD-1000 7.62 7.62 7.62 7.62 ERISYS RDGE 1.25 0.75 1.75 2.25 2-(2-Butoxyethoxy)ethyl acetate 2.14 2.14 2.14 2.14 HYCAR® CTBN 1300X8 1.87 1.87 1.87 1.87 2MAOK 1.75 1.75 1.75 1.75 EA0295 75.00 76.30 73.60 72.20 SILQUEST® A-186 1.00 1.00 1.00 1.00 Test Results RTDSS Kg / mm2 14.5 10.8 13.5 11 HTDSS Kg / mm2 2.2 1.6 2.3 2 The results in Table 3 show that, according to the present invention, the presence of a certain amount of RDGE can improve both RTDSS and HTDSS.

[0122] [] [Example of the Invention] [9] [to]

[12] In this set of examples, conductive epoxy resin compositions using different anhydride curing agents of the present invention (Examples 9 to 12) were prepared based on the weight percentages specified in the table below. The RTDSS and HTDSS of the samples were tested. Table 4 Components Example 9 Example 10 Example 11 Example 12 DDSA 9.37 - - - jER Cure® YH307 - 7.44 - - Epiclon B-570-H - - 7.75 - RIKACID MH700 - - - 7.75 XD-1000 7.62 7.30 7.24 7.24 ERISYS RDGE 1.25 1.34 1.34 1.34 2-(2-Butoxyethoxy)ethyl acetate 2.14 2.30 2.30 2.30 HYCAR® CTBN 1300X8 1.87 1.82 1.82 1.82 2MAOK 1.75 1.88 1.88 1.88 EA0295 75.00 76.85 76.60 76.60 SILQUEST® A-186 1.00 1.07 1.07 1.07 Test Results RTDSS Kg / mm2 14.5 12.5 15.6 15 HTDSS Kg / mm2 2.2 1.8 2 2.1 The results in Table 4 above show that there are no restrictions on the type of anhydride curing agent according to the present invention.

[0123] Although some preferred embodiments have been described, many modifications and variations can be made thereto in light of the teachings above. Therefore, it should be understood that the invention can be practiced as expressly described herein without departing from the scope of the appended claims.

Claims

1. A conductive epoxy resin composition comprising: (A) at least one epoxy resin system comprising: (A1) at least one epoxy resin having at least two aromatic groups containing glycidyloxy groups bonded together by divalent intracyclic hydrocarbon groups or aryl groups, and C1 to C6 alkyl groups as desired; and (A2) at least one resorcinol diglycidyl ether resin present in an amount of 0.2 to 5.0% by weight 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 anhydride curing agent; (C) at least one solvent as desired; (D) at least one conductive filler; and (E) at least one catalyst as desired, wherein the divalent intracyclic hydrocarbon group is represented by one of the following structural formulas X1 to X3: wherein each ring contains one or more R, and each R independently represents a hydrogen atom or a methyl group; and * represents a binding site attached to the aromatic group containing the glycidyloxy group.

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

3. The composition of claim 1 or 2, wherein the epoxy resin (A1) is selected from biphenyl-type epoxy resins containing glycidyl oxy groups, naphthalene-type epoxy resins containing glycidyl oxy groups, epoxy resins containing glycidyl oxy groups having divalent internal ring hydrocarbon groups, and combinations thereof.

4. The composition of claim 1 or 2, wherein the resorcinol diglycidyl ether resin (A2) is present in an amount of 0.5 to 3.0% by weight based on the total weight of the composition.

5. The composition of claim 1 or 2, wherein the anhydride curing agent (B) is selected from phthalic anhydride, maleic anhydride, trimellitic anhydride, pyromellitic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, nadic methyl acid anhydride, nadic anhydride, glutaric anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, and combinations thereof.

6. The composition of claim 1 or 2, wherein the conductive filler (D) is selected from silver, copper, boron nitride, aluminum oxide, gold, nickel, silver-containing alloys, copper-containing alloys, nickel-containing alloys, and combinations thereof.

7. The composition of claim 1 or 2, wherein the catalyst (E) is selected from phenylurea, boron trichloride ammonium complex, imidazole, aliphatic diurea, phenol, resorcinol, and combinations thereof.

8. The composition of claim 1 or 2, wherein the composition further comprises additives selected from: toughening agents, fluxes, peroxides, flow additives, adhesion promoters, rheology modifiers, and combinations thereof.

9. The composition of claim 1 or 2, wherein the component (A1) is present in an amount of 1 to 15% by weight based on the total weight of the composition.

10. The composition of claim 1 or 2, wherein the 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 claim 1 or 2, wherein the component (C) is present in an amount of 0.5 to 20% by weight based on the total weight of the composition.

12. The composition of claim 1 or 2, wherein the 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 a conductive epoxy resin composition as claimed in any one of claims 1 to 12.

14. A semiconductor device comprising a cured product of a conductive epoxy resin composition as claimed in claim 13.

15. Use of a cured product of a conductive epoxy resin composition as claimed in any one of claims 1 to 12 or a conductive epoxy resin composition as claimed in claim 13, for use in the manufacture of semiconductor packages or microelectronic devices.