WO2017080040A1 - Damp-heat-resistant and highly reliable conductive silver epoxy adhesive, method for preparing same, and application thereof - Google Patents

Abstract

The present invention provides a damp-heat-resistant and highly reliable conductive silver epoxy adhesive, a method for preparing same, and an application thereof. Considering the total weight of the damp-heat-resistant and highly reliable conductive silver epoxy adhesive as 100%, the damp-heat-resistant and highly reliable conductive silver epoxy adhesive is prepared from the following raw materials: 65-85% of metallic silver powder, 5.0-30% of epoxy resins, 1-15% of an active heterocyclic compound having a triazine structure, 0.5-10% of acrylic resin, 1.0-3.5% of a curing agent, 0.05-1.5% of an accelerator, and 0.01-3% of functional additives. The present invention further provides a method for preparing the conductive silver adhesive and an application thereof. The conductive silver adhesive prepared in the present invention has good conductive, mechanical, bonding and damp-heat resistant properties, can effectively alleviate the problem of the poor damp-heat resistant property of existing conductive silver adhesives and the problem of red zones occurring during the aging process, and meanwhile can significantly improve the reliability of device and product packaging.

Description

Moist heat resistant high reliability epoxy conductive silver glue and preparation method and application thereof Technical field

The invention relates to a moisture-resistant and high-reliability epoxy conductive silver glue, a preparation method and application thereof, and belongs to the technical field of microelectronic packaging.

Background technique

With the miniaturization and miniaturization of electronic components and the rapid development of high density and high integration of printed circuit boards, conductive adhesives, as a material that can replace lead-tin solder, have become the core material of the microelectronics industry. The importance is increasingly prominent. Because the conductive adhesive bonds the conductive particles together by the bonding of the matrix resin to form a conductive path, the conductive connection of the material to be bonded is realized. The material has low bonding temperature, wide bonding temperature range, simple process, flexible and variable formulation, can be made into slurry, realizes fine pitch and ultra-fine pitch interconnection ability, and has good adhesion and is suitable for each Bonding of the surface of a type substrate (flexible substrate, ceramic/glass substrate, laminate, molding compound, etc.). At the same time, it also has the advantages of good environmental compatibility, high production efficiency and low cost, which makes it more suitable for the needs of the modern microelectronics industry for conductive connections. However, compared with metal solders, conductive adhesives also have some shortcomings in performance, such as high volume resistivity, poor thermal conductivity, insufficient bonding strength, unstable contact resistance, etc., especially after high temperature and high humidity aging experiments. It is easy to produce interface delamination, which leads to failure of bonding, electrical connection and mechanical properties. These have become important constraints limiting the application of conductive adhesives in the field of microelectronic assembly. Therefore, the development of conductive adhesive with high reliability has become the focus of current research.

As the base resin of conductive adhesive, epoxy resin is widely used in the electronics industry as coating coating material, bonding potting material and laminated composite material because of its excellent bonding property, mechanical strength and dimensional stability. Wait. However, it has been found in practice that after the epoxy resin material is used in a hot and humid environment for a period of time, performance may be degraded, especially in an environment where the temperature is 50-60 ° C and the humidity exceeds 95%. The ability will continue to weaken, and may even directly fail, so that the epoxy resin material loses its original role, which poses a great challenge to the use of epoxy resin materials. Therefore, solving the moisture and heat resistance of materials has become a key issue in the research field of microelectronic package reliability.

At present, the method for improving the heat and humidity resistance of an epoxy resin mainly improves the crosslinking density, introduces moist heat resistance and moisture resistance groups or segments, or reduces and blocks the polar groups generated in the cured structure. content. For example, Chinese patent CN 102329587A introduces a thermosetting phenolic resin to improve the structural compactness and heat resistance of the cured product, making the material less susceptible to electrochemical corrosion and reducing hygroscopicity. The prepared conductive paste is at 85 ° C and 85% RH. After 500 hours of aging, the volume resistivity changes by less than 20%, remains on the order of 10 ^-5 Ω/cm, has good electrical conductivity and high contact resistance stability. However, the adhesive strength of the adhesive is only 8 MPa, which leads to less than ideal reliability. Chinese patent CN103409093A uses tetrafunctional N, N, N', N'-tetraglycidyl-4,4'-diaminodiphenyl ether epoxy resin as the main resin, which has a phenyl group in its molecular structure. The high epoxy functionality gives the cured product a relatively high crosslink density and exhibits good high temperature resistance. At the same time, the resin has an ether bond in its molecular structure, and the molecular flexibility is good, which can improve the toughness and water resistance of the material. After curing, the adhesive prepared by the method has a very low saturated moisture absorption rate of only 0.43%, and also has an ultra-high bonding strength of 36.9 MPa, and can be applied to glass, ceramic, metal, epoxy resin-based composite materials. Bonding of the substrate. However, since the molecular structure contains a tertiary amine, it can catalyze the epoxy polymerization itself, resulting in poor storage stability of the system, which in turn affects its special application in the electronics industry. Chinese patent CN 102925100A is modified with hydrophobic phenyl silicone resin to give the material good temperature resistance. The maximum temperature can reach 300 ° C, the resistivity can reach 2-4×10 ^-5 Ω/cm, and the thermal conductivity is 4- 6w/k·m. Chinese patent CN 101126003A introduces a macromolecular anthracene ring skeleton in the crosslinked network to improve the moisture and heat resistance of the material. By comparing with the conventional modified epoxy resin, the water absorption rate of the material is reduced by 60%, about 1.4%, and It maintains a shear strength of 10 MPa or more at a high temperature of 200 ° C, and is particularly suitable for occasions where high shear strength is required in a hot and humid environment. However, since ruthenium-based epoxy resins are not currently commercially available, special custom synthesis is required, and the process is cumbersome, resulting in relatively expensive products. Chinese patent CN 102786901A is composed by introducing a large proportion of polyamide imine segment in epoxy resin, because the main chain and side chain of the cured product contain a large amount of benzene ring and imide group, so that the molecular chain has Very large rigidity, tensile strength up to 160MPa, thermal decomposition temperature is also significantly improved, super high 400 °C. In addition, the introduction of the polyamide imine molecular structure also uses partial fluorine substitution, which can exhibit good hydrophobicity and moist heat resistance. Although the above several methods have well solved the heat and humidity resistance of epoxy resin materials, there are different degrees of defects in practical applications, such as poor storage stability, high curing temperature, complicated synthesis process, and curing of the glue. The temperature needs to reach 190 ° C. Under this temperature condition, the electronic components are easily damaged, so it is only suitable for special applications such as high temperature and high pressure.

At present, existing conductive silver adhesives have some shortcomings in practical application, such as poor storage stability, high curing temperature, complicated synthesis process, etc., especially in semiconductor packaging enterprises, which are found for chip keys in practical applications. The conductive silver paste used in the pre-aging process will have 6-10% red zone, which is the phenomenon of peeling and cracking of the chip and the bracket at the edge, which is due to the poor heat and humidity resistance of the bonding material used. Caused.

Summary of the invention

In order to solve the above technical problems, an object of the present invention is to provide a moisture-resistant and highly reliable epoxy conductive silver paste.

Another object of the present invention is to provide a method for preparing the above-mentioned moisture-resistant high-reliability epoxy conductive silver paste.

It is also an object of the present invention to provide an application of the above-mentioned moisture-resistant high-reliability epoxy conductive silver paste as a chip binder for electronic components and its use in electrode welding.

In order to achieve the above object, the present invention provides a moisture-resistant and high-reliability epoxy conductive silver paste, which is 100% by weight based on the total weight of the moisture-resistant and high-reliability epoxy conductive silver paste. The oxygen conductive silver paste is prepared from the following raw materials: 65-85 wt% of metallic silver powder, 5.0-30 wt% of epoxy resin, 1-15 wt% of active heterocyclic compound having a triazine structure, and 0.5-10 wt% of acrylic acid. Resin, 1.0-3.5 wt% curing agent, 0.05-1.5 wt% accelerator and 0.01-3 wt% functional auxiliary.

According to the silver paste of the present invention, preferably, the moisture-resistant heat-reliable epoxy conductive silver paste is prepared from the following raw materials, based on 100% of the total weight of the moisture-resistant heat-reliable epoxy conductive silver paste; 65-85 wt% metal silver powder, 5.0-30 wt% epoxy resin, 1-15 wt% active heterocyclic compound having a triazine structure, 0.5-10 wt% acrylic resin, 1.0-3.5 wt% curing agent 0.05-1.5 wt% of a promoter, 0.01-3 wt% of a functional auxiliary, and 1-10 wt% of a toughening diluent.

According to the silver paste of the present invention, preferably, the metal silver powder is selected from one or a combination of spherical, flake, rod and dendritic metal silver powder;

More preferably, the metal silver powder is a combination of a sheet metal silver powder and a spherical metal silver powder;

Still more preferably, the metal silver powder has a size of from 0.1 to 10 μm, further preferably from 0.5 to 5 μm. The "size" of irregularly shaped metallic silver powder is defined in the art as the length of the longest portion of the plane.

The "combination of several metal silver powders" involved in the present invention may be a combination of several metal silver powders in any suitable ratio, and the present invention does not require a ratio relationship between the amounts of the metal silver powders, and those skilled in the art may According to the needs of on-site operation, the appropriate dosage ratio relationship is selected. However, it should be noted that the sum of the above-mentioned several kinds of conductive silver powders needs to meet the limit of the amount of raw materials used in the present invention.

According to the silver paste of the present invention, the epoxy resin used in the present invention may be any epoxy resin which is suitable for the conductive silver paste disclosed in the prior art; preferably, the epoxy resin is selected from the group consisting of bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, hydantoin epoxy resin, 4,4' diaminodiphenylmethane tetraglycidylamine type epoxy resin, triglycidyl P-aminophenol type epoxy resin, 4,5-epoxycyclohexane-1,2- a combination of one or more of diglycidyl dicarboxylate (TDE-85) epoxy resin, alicyclic epoxy resin, and novolac epoxy resin;

More preferably, the epoxy resin is a low viscosity bisphenol F type epoxy resin, 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester (TDE-85) epoxy resin, 4, 4' diaminodiphenylmethane tetraglycidylamine type epoxy resin and triglycidyl p-aminophenol type epoxy resin.

The "combination of several kinds of epoxy resins" involved in the present invention may be a combination of several kinds of epoxy resins in any suitable ratio, and the present invention does not require the proportional relationship between the amounts of the epoxy resins. The technician can select the appropriate dosage ratio according to the needs of the field operation. However, it should be noted that the sum of the above-mentioned several kinds of epoxy resins needs to meet the limitation of the amount of the raw materials of the present invention.

According to the silver paste of the present invention, the alicyclic epoxy resin used is a conventional product in the art, and any of the alicyclic epoxy resins disclosed in the prior art which can be suitable for the conductive silver paste can be used. The present invention; preferably the alicyclic epoxy resin comprises 3,4-epoxycyclohexenemethyl-3,4-epoxycyclohexenoate, 4,5-epoxycyclohexane-1,2 - Diglycidyl dicarboxylate or bis((3,4-epoxycyclohexyl)methyl) adipate.

According to the silver paste of the present invention, the hyacinol used is a conventional product in the art, and any of the hyacinol resins disclosed in the prior art which can be suitable for the conductive silver paste can be used in the present invention. .

According to the silver paste of the present invention, the phenolic epoxy resin used is a conventional product in the art, and any of the phenolic epoxy resins disclosed in the prior art which can be suitable for the conductive silver paste can be used in the present invention; In a preferred embodiment of the present invention, the phenolic epoxy resin comprises a phenolic epoxy resin of the type EPALLOY-8240 produced by Emerald Corporation of the United States; a phenolic epoxy resin of the type NPPN-631 produced by Taiwan Nanya Plastic Industry Co., Ltd. The phenolic epoxy resin produced by Dow Chemical (DOW) is DEN431 and DEN438; the phenolic epoxy resin produced by Guangzhou Kailuo Chemical Co., Ltd. is F-51.

According to the silver paste of the present invention, the active heterocyclic compound having a triazine structure may be all compounds containing a triazine structure, and preferably, the active heterocyclic compound having a triazine structure is selected from 1, 2, 4-triazine, 1,3,5-triazine, 4-amino-1,3,5-triazin-2-one, 3-amino-5-phenyl-1,3,5-triazine, 2 , 4-diamino-6-phenyl-1,3,5-triazine, hexamethylene diisocyanate (HDI) trimer and its closure, toluene diisocyanate (TDI) trimer and its closure a combination of one or more of triglycidyl isocyanurate, triallyl isocyanurate, and amino-substituted benzotriazine derivatives;

More preferably, the active heterocyclic compound having a triazine structure includes triglycidyl isocyanurate or triallyl isocyanurate.

The "combination of several active heterocyclic compounds having a triazine structure" referred to in the present invention may be a combination of several active heterocyclic compounds having a triazine structure in any suitable ratio, and the present invention has three The proportion relationship between the active heterocyclic compounds of the azine structure is not required, and those skilled in the art can select an appropriate dosage ratio according to the needs of the field operation, but it should be noted that the above several active impurities having a triazine structure The sum of the amounts of the cyclic compounds needs to satisfy the limit of the amount of the raw materials used in the present invention.

According to the silver paste of the present invention, the hexamethylene diisocyanate (HDI) trimer block and the toluene diisocyanate (TDI) trimer block are all conventional products in the art; The diisocyanate (HDI) trimer block comprises a hexamethylene diisocyanate (HDI) trimer and a seal formed from phenol, caprolactam and butanone oxime, and the toluene diisocyanate (TDI) trimer block comprises A closure formed of a toluene diisocyanate (TDI) trimer with phenol, caprolactam, butanone oxime or the like.

The amino-substituted benzotriazine derivatives used in accordance with the present invention are conventional products in the art, and in a preferred embodiment of the invention, 3-amino-7-methyl-1,2 , 4-benzotriazine-1-oxide or 3-biamino-7-methoxy-1,2,4-benzotriazine, and the like.

According to the silver paste of the present invention, the acrylic resin used may be any epoxy resin which is suitable for the conductive silver paste disclosed in the prior art; preferably, the acrylic resin is selected from the group consisting of acrylate prepolymers, A combination of one or more of a polyfunctional acrylic resin, an epoxy modified acrylic resin, a polyurethane modified acrylic resin, a silicone modified acrylic resin, and a hyperbranched polyester modified acrylic resin.

According to the silver paste of the present invention, the acrylate prepolymer used is a conventional product in the art, and a commercially available acrylate prepolymer can be used in the present invention. In a preferred embodiment of the present invention, the acrylic acid The ester prepolymer has a functionality of ≥ 2 and a viscosity of ≤ 10000 mPas. Here, the functional group participating in the reaction referred to in the definition of the functionality is an acrylate group.

According to the silver paste of the present invention, the polyfunctional acrylic resin used is a conventional product in the art, and a commercially available polyfunctional acrylic resin can be used in the present invention. In a preferred embodiment of the present invention, the polyfunctional acrylic acid is used. The resin includes an acrylic resin having a number of acrylate groups of ≥ 2 and a viscosity of ≤ 10 Pas.

According to the silver paste of the present invention, the epoxy-modified acrylic resin, the polyurethane-modified acrylic resin, the silicone-modified acrylic resin, and the hyperbranched polyester-modified acrylic resin are all conventional products in the art, and any commercially available ones are commercially available. The above substances can be used in the present invention.

According to the silver paste of the present invention, the curing agent used may be any one of the curing agents disclosed in the prior art which can be suitable for the conductive silver paste; preferably, the curing agent is selected from the group consisting of an imidazole curing agent and an imidazole modification. Sex agent curing agent, One of an aromatic amine curing agent, a dicyandiamide, a dicyandiamide derivative curing agent, an organic acid hydrazide curing agent, a boron trifluoride-amine complex curing agent, and a microcapsule curing agent or Several combinations.

The "combination of several curing agents" involved in the present invention may be a combination of several curing agents in any suitable ratio, and the present invention does not require a ratio relationship between the curing agents, and those skilled in the art may According to the needs of on-site operation, the appropriate dosage ratio relationship is selected. However, it should be noted that the sum of the above-mentioned several curing agents needs to meet the limit of the amount of raw materials used in the present invention.

The imidazole curing agent used in the present invention is a conventional one in the art, and preferably the imidazole curing agent includes 2-methylimidazole, 2-phenylimidazole, 2-ethyl-4-methylimidazole or 1,2- Dimethylimidazole.

The imidazole modified material curing agent used in the present invention is a conventional material in the art, and preferably the imidazole modified material curing agent comprises a cyanoethyl modified imidazole curing agent, a long alkyl chain modified imidazole curing agent, PN-23, PN-31, PN-40 or PN-50;

More preferably, the cyanoethyl modified imidazole curing agent comprises 1-cyanoethyl-2-ethyl-4-methylimidazole or 1-cyanoethyl-2-phenylimidazole;

The long alkyl chain-modified imidazole curing agent includes 2-heptadecylimidazole or 2,4-diamino-6-(2-undecylimidazolyl)-1-ethyltriazine.

In a preferred embodiment of the present invention, the 2-heptadecylimidazole used is a C17Z long alkyl chain-modified imidazole curing agent manufactured by Shikoku Chemicals Co., Ltd.;

The 2,4-diamino-6-(2-undecyl imidazolyl)-1-ethyltriazine used is a long alkyl chain-modified imidazole of the type C11Z-A produced by Shikoku Chemicals Co., Ltd., Japan. Class curing agent;

The PN-23, PN-31, PN-40, and PN-50 used were all imidazole-modified curing agents produced by Ajinomoto Co., Ltd.

The aromatic amine curing agent used in the present invention is a conventional one in the art, and the aromatic amine curing agent includes 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfone, and Phenylenediamine, m-xylylenediamine or diethyltoluenediamine.

The dicyandiamide derivative curing agent used in the present invention is a conventional material in the art, and the dicyandiamide derivative curing agent includes a 3,5-disubstituted aniline modified dicyandiamide derivative and m-toluidine modified Sodium dicyandiamide or benzoquinone modified dicyandiamide; in a preferred embodiment of the invention, the 3,5-disubstituted aniline modified dicyandiamide derivative used is a model manufactured by Ciba-Geigy Co., Ltd. A dicyandiamide derivative curing agent for HT2833 and HT2844.

The organic acid hydrazide curing agent used in the present invention is a substance conventionally known in the art, and the organic acid hydrazide is cured. The agent includes succinic acid hydrazide, adipic acid dihydrazide, sebacic acid hydrazide, isophthalic acid hydrazide or p-hydroxybenzoic acid hydrazide (POBH).

The boron trifluoride-amine complex type curing agent used in the present invention is a substance conventional in the art, and the boron trifluoride-amine complex type curing agent includes boron trifluoride and ethylamine, piperidine, and the like. a complex formed by ethylamine or aniline.

The microcapsule curing agent used in the present invention is a conventional curing agent used in the art. In a preferred embodiment of the present invention, the microcapsule curing agent used in the present invention includes Novacure HX3721, HX3721, and HX3921HP manufactured by Asahi Kasei Chemicals Co., Ltd., Japan. And HX3941HP poly polyamine modified imidazole microcapsule curing agent.

According to the silver paste of the present invention, the accelerator used may be any one of the promoters disclosed in the prior art which is suitable for the conductive silver paste; preferably, the accelerator is selected from the group consisting of 2, 4, 6-three. (dimethylaminomethyl) phenol, tris(2-ethylhexanoic acid) salt of 2,4,6-tris(dimethylaminomethyl)phenol, imidazole compound and salt complex thereof, triphenylphosphine , tetrabutylphosphonium bromide, tetrabutylphosphonium acetate, tetrabutylphosphine oxide, benzyltriphenylphosphonium bromide, 1-cyanoethyl-2-ethyl-4-methylimidazole, tetramethylguanidine, A combination of one or more of a metal salt of benzoyl peroxide, organic urea, and acetylacetone.

The "combination of several accelerators" involved in the present invention may be a combination of several accelerators in any suitable ratio, and the present invention does not require a proportional relationship between the accelerators, and those skilled in the art may According to the needs of on-site operation, the appropriate dosage ratio relationship is selected. However, it should be noted that the sum of the above-mentioned several accelerators needs to meet the limit of the amount of raw materials used in the present invention.

According to the silver paste of the present invention, the imidazole compound and the salt complex thereof used are products commonly used in the art, and in particular, the imidazole compound includes 2-ethyl-4-methylimidazole or 2-methyl group. 4-Ethyl imidazole; a salt complex of an imidazole compound includes an imidazolium salt complex formed of the imidazole compound with copper sulfate, copper chloride, copper bromide, nickel chloride or the like.

According to the silver paste of the present invention, the metal salt of acetylacetone used is a product commonly used in the art, and preferably the metal salt of acetylacetone includes an aluminum salt of acetylacetone, a cobalt salt of acetylacetone, a zinc salt of acetylacetone, a copper salt of acetylacetone, a nickel salt of acetylacetone, a manganese salt of acetylacetone, a chromium salt of acetylacetone, a titanium salt of acetylacetone or a zirconium salt of acetylacetone.

According to the silver paste of the present invention, the organic urea used includes N-p-chlorophenyl-N,N'-dimethylurea, dimethylimidazolium, and Evonik Degussa, respectively. Produced by ur-200, UR-300 and UR-500 organic urea, Emerald Performance Materials LLC The models are OMICURE U-24M, OMICURE U-35M, OMICURE U-52M and OMICURE U-405M organic urea.

According to the silver paste of the present invention, the toughening diluent used may be any toughening diluent which is suitable for the conductive silver paste disclosed in the prior art; preferably, the toughening diluent is selected from the end Carboxyl liquid nitrile rubber, hydroxyl terminated liquid nitrile rubber, terminal amino liquid nitrile rubber, terminal epoxy liquid nitrile rubber, terminal carboxyl liquid polybutadiene rubber, hydroxyl terminated liquid polybutadiene rubber, epoxy seal Polybutadiene rubber, liquid polyurethane, core-shell rubber particles, hyperbranched polyester, n-butyl glycidyl ether, 1,4-butanediol diglycidyl ether, trimethylolpropane glycidyl ether, C Alcohol triglycidyl ether, sterol glycidyl ether, ethylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, allyl glycidyl ether, phenyl glycidyl ether, benzyl glycidyl ether, 2-B Hexyl hexyl glycidyl ether, C ₁₂ -C ₁₄ alkyl glycidyl ether, diethylene glycol glycidyl ether, p-tert-butyl glycidyl ether, cyclohexane diol diglycidyl ether and resorcinol diglycidyl ether One or a combination of several.

The "combination of several toughening diluents" referred to in the present invention may be a combination of several toughening diluents in any suitable ratio, and the present invention does not require a proportional relationship between the amounts of the toughening diluents. Those skilled in the art can select an appropriate dosage ratio relationship according to the needs of the field operation. However, it should be noted that the sum of the above-mentioned several kinds of toughening diluents needs to satisfy the limitation of the amount of raw materials in the present invention.

According to the silver paste of the present invention, the core-shell rubber particles used are commercially available products in the field. In a preferred embodiment of the present invention, the core-shell rubber particles used may be produced by Wacker Chemie AG, Germany. The core shell rubber particles of type P52.

According to the silver paste of the present invention, the hyperbranched polyester used is a conventional toughening diluent used in the art, and the toughening diluent may be any commercially available product, and in a preferred embodiment of the present invention, The toughening thinner is selected from the hyperbranched polyester of HyPer H10, HyPer H20, HyPer H30 or HyPer H40 produced by Wuhan Hyperbranched Resin Technology Co., Ltd. and the Boltorn H20 and Boltorn H30 produced by Shanghai Xibao Biotechnology Co., Ltd. Hyperbranched polyester of Boltorn H40, Boltorn U3000, Boltorn W3000 or Boltorn H2004.

According to the silver paste of the present invention, preferably, the functional auxiliary comprises one or a combination of an antifoaming agent, a dispersing agent, a leveling agent, a coupling agent and a thixotropic agent. A person skilled in the art can select one or a combination of functional additives such as an antifoaming agent, a dispersing agent, a leveling agent, a coupling agent and a thixotropic agent to be added according to the requirements of the field operation.

In a preferred embodiment of the present invention, the leveling agent is selected from the group consisting of TEGO900 and TEGO-B1484. TEGO-410, TEGO-245, BYK-354, BYK-302, BYK-323 or BYK-333;

In a preferred embodiment of the present invention, the antifoaming agent is selected from BYK-A530;

In a preferred embodiment of the present invention, the thixotropic agent is selected from the group consisting of BYK-R605, fumed silica, hydrogenated castor oil or polyamide wax;

In a preferred embodiment of the present invention, the dispersing agent is selected from the group consisting of BYK-110, NP-10, NP-15, NP-40, Span series (such as Span-80, etc.) or Tween series;

In a preferred embodiment of the present invention, the coupling agent comprises γ-aminopropyltriethoxysilane and γ-aminopropyltrimethoxysilane (such as KH-550 produced by Nanjing Qianjin Chemical Co., Ltd.). Coupling agent), γ-(2,3-epoxypropoxy)propyltrimethoxysilane (such as KH-560 coupling agent produced by Nanjing Qianjin Chemical Co., Ltd.), γ-(B Diamino)propyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, isopropyltris(isostearic acid) titanate, isopropyl tris(10) Dialkylbenzenesulfonyl) titanate or distearyloxyisopropylaluminate.

According to the silver glue of the present invention, the above TEGO900, TEGO-B1484, TEGO-410 and TEGO-245 are the corresponding auxiliary agents produced by German Digao; BYK-354, BYK-302, BYK-323, BYK-333, BYK -A530, BYK-R605, BYK-110 are the corresponding additives produced by BYK Chemicals in Germany; NP-10, NP-15 and NP-40 are the corresponding additives produced by Dow Chemical in the United States.

The invention also provides a preparation method of the above-mentioned moisture-resistant high-reliability epoxy conductive silver paste, which comprises the following steps:

a, epoxy resin, toughening diluent, active heterocyclic compound with a triazine structure and acrylic resin are mixed uniformly to obtain a mixture A;

b, sequentially adding a curing agent, a promoter and a functional auxiliary to the mixture A to obtain a colloid B;

c. Adding metal silver powder to the colloid B, stirring uniformly, and then dispersing, grinding, filtering, vacuum defoaming, and packaging to obtain the moisture-resistant and high-reliability epoxy conductive silver paste.

According to the preparation method of the present invention, the metal silver powder may be added in batches or may be added in one time, and those skilled in the art may select a suitable joining method to add metal silver powder according to the needs of field operations.

According to the production method of the present invention, in a preferred embodiment of the present invention, the above-described dispersion and grinding process can be carried out in a three-roll mill.

According to the preparation method of the present invention, the order of adding the above various raw materials is not strictly required, but considering the stability of the above raw material products, in the preferred embodiment of the present invention, it is necessary to follow the above. The feeding sequence defined in the preparation method is carried out in the order of addition. In addition, the preparation process of the present invention is carried out at room temperature, and the present invention does not require time for each step, and those skilled in the art can control the appropriate time according to the requirements of the field operation, as long as the operation purpose can be achieved.

The invention also provides the above application of the moisture-resistant high-reliability epoxy conductive silver paste as a chip binder for electronic components and its application in electrode welding.

In accordance with the application of the present invention, the electronic components include LEDs, carbon film potentiometers, chip resistors, tantalum/aluminum capacitors, NTC/PTC thermistors, quartz transistors, integrated circuits, and the like.

In the preparation of the moisture-resistant and high-reliability epoxy conductive silver paste, the active heterocyclic compound having a triazine structure containing an active reactive group and having heat and humidity resistance is introduced into the epoxy-based material, and an acrylic resin is added, and acrylic acid is added. The resin can form a network interpenetrating dense structure with the epoxy resin during the curing process, thereby preparing the moisture-resistant high-reliability epoxy conductive silver paste of the present invention.

The moisture-resistant and high-reliability epoxy conductive silver adhesive of the invention not only has good electrical conductivity, but also has more excellent mechanical properties, bonding properties, especially moist heat resistance, so that the existing conductive silver rubber can be effectively solved. Poor heat and humidity and red zone problems in the aging process, and can also significantly improve the reliability of packaged devices and products; in addition, the conductive silver adhesive has a long pot life, good storage stability, low curing temperature, and development for the microelectronic packaging industry. Has a high practical value. In a preferred embodiment of the present invention, the viscosity of the moisture-resistant high-reliability epoxy conductive silver paste prepared by the present invention is 15000-20000 mPas, and the conductivity of the conductive silver paste after curing is 1-8×10 ^{- 4} Ω/cm, shear strength 19-26MPa, maximum temperature up to 280°C.

The preparation method of the moisture-resistant and high-reliability epoxy conductive silver glue of the invention has the advantages of simple process and good controllability.

detailed description

The technical features of the present invention are described in detail below with reference to the specific embodiments of the present invention, but are not to be construed as limiting the scope of the invention.

Example 1

The embodiment provides a method for preparing a moisture-resistant high-reliability epoxy conductive silver paste, wherein the preparation method comprises the following steps:

Weigh bisphenol F type epoxy resin in sequence: 12 parts by weight, hyperbranched polyester modified toughener: 2 parts by weight, triallyl isocyanurate: 4.0 parts by weight, epoxy modified acrylate a compound: 1 part by weight, trimethylolpropane glycidyl ether: 3.0 parts by weight, and mixed in a high-speed mixer to obtain a mixture A;

Then, 2-methyl-4-ethylimidazole was added to the obtained mixture A: 0.7 part by weight, dicyandiamide: 1.0 part by weight, benzoyl peroxide: 0.5 part by weight, polyamide wax: 0.3 part by weight , KH-560 silane coupling agent: 0.3 parts by weight, TEGO-245: 0.2 parts by weight, continue to mix it in a high-speed mixer to obtain a conductive silver paste matrix B;

Finally, 75 parts by weight of silver powder is added to the conductive silver gum matrix B prepared above in a batch and thoroughly stirred, and then placed in a three-roll mill for grinding, dispersion, filtration, vacuum defoaming, and packaging to obtain resistance. Wet heat and high reliability epoxy conductive silver glue.

Example 2

The embodiment provides a method for preparing a moisture-resistant high-reliability epoxy conductive silver paste, wherein the preparation method comprises the following steps:

The bisphenol F type epoxy resin was weighed in order: 12 parts by weight, epoxy-terminated polybutadiene rubber: 2 parts by weight, triglycidyl isocyanurate: 5.0 parts by weight, epoxy-modified acrylate compound: 2.0 parts by weight, and uniformly mixed in a high-speed mixer to obtain a mixture A;

Then, dicyandiamide was added to the obtained mixture A: 1.0 part by weight, 2-methyl-4-ethylimidazole: 0.7 part by weight, benzoyl peroxide: 0.5 part by weight, hydrogenated castor oil: 0.3 part by weight , KH-560 silane coupling agent: 0.3 parts by weight, NP-10: 0.2 parts by weight, continue to mix it in a high-speed mixer to obtain a conductive silver paste matrix B;

Finally, 76 parts by weight of silver powder is added to the conductive silver gum matrix B prepared in the above batch and thoroughly stirred, and then placed in a three-roll mill for grinding, dispersing, filtering, vacuum defoaming, and packaging to obtain resistance. Wet heat and high reliability epoxy conductive silver glue.

Example 3

The embodiment provides a method for preparing a moisture-resistant high-reliability epoxy conductive silver paste, wherein the preparation method comprises the following steps:

The bisphenol A type epoxy resin was weighed in order: 12 parts by weight, epoxy-terminated polybutadiene rubber: 2 parts by weight, triallyl isocyanurate: 4.0 parts by weight, epoxy-modified acrylate Compound: 1.0 parts by weight, and mixed in a high-speed mixer to obtain a mixture A;

Then, dicyandiamide was added to the obtained mixture A: 1.0 part by weight, 1-cyanoethyl-2-ethyl-4-methylimidazole: 0.7 part by weight, benzoyl peroxide: 0.5 part by weight, gas phase Silica: 0.3 parts by weight, KH-550 silane coupling agent: 0.3 parts by weight, Span 80: 0.2 parts by weight, and continued to be uniformly mixed in a high-speed mixer, Obtaining a conductive silver paste matrix B;

Finally, 78 parts by weight of silver powder is added to the conductive silver gum matrix B prepared in the above batch and thoroughly stirred, and then placed in a three-roll mill for grinding, dispersing, filtering, vacuum defoaming, and packaging to obtain resistance. Wet heat and high reliability epoxy conductive silver glue.

Example 4

The embodiment provides a method for preparing a moisture-resistant high-reliability epoxy conductive silver paste, wherein the preparation method comprises the following steps:

The bisphenol A type epoxy resin was weighed in order: 12 parts by weight, epoxy-terminated polybutadiene rubber: 2 parts by weight, blocked type 1,6-hexamethylene diisocyanate trimer (hexamethylene diisocyanate (HDI) a blocking form of a trimer and phenol): 2.0 parts by weight, an epoxy-modified acrylate compound: 5.0 parts by weight, and uniformly mixed in a high-speed mixer to obtain a mixture A;

Then, dicyandiamide was added to the obtained mixture A: 1.0 part by weight, 1-cyanoethyl-2-ethyl-4-methylimidazole: 0.7 part by weight, benzoyl peroxide: 0.5 part by weight, poly Amide wax: 0.3 parts by weight, KH-550 silane coupling agent: 0.3 parts by weight, TEGO-0.2 parts by weight, continue to mix and homogenize in a high-speed mixer to obtain a conductive silver gum matrix B;

Finally, 76 parts by weight of silver powder is added to the conductive silver gum matrix B prepared in the above batch and thoroughly stirred, and then placed in a three-roll mill for grinding, dispersing, filtering, vacuum defoaming, and packaging to obtain resistance. Wet heat and high reliability epoxy conductive silver glue.

Example 5

The embodiment provides a method for preparing a moisture-resistant high-reliability epoxy conductive silver paste, wherein the preparation method comprises the following steps:

Weigh bisphenol F type epoxy resin in sequence: 12 parts by weight, hyperbranched polyester modified toughener: 2 parts by weight, triglycidyl isocyanurate: 1.0 part by weight, triallyl isocyanurate : 3.0 parts by weight, epoxy modified acrylate compound: 3.0 parts by weight, and uniformly mixed in a high speed mixer to obtain a mixture A;

Then, dicyandiamide was added to the obtained mixture A: 1.0 part by weight, 2-methyl-4-ethylimidazole: 0.7 part by weight, benzoyl peroxide: 0.5 part by weight, polyamide wax: 0.3 part by weight , KH-560 silane coupling agent: 0.3 parts by weight, TEGO-245: 0.2 parts by weight, and continue to mix it in a high-speed mixer to obtain a conductive silver paste matrix B;

Finally, 76 parts by weight of silver powder was added in batches to the conductive silver paste matrix B prepared above and thoroughly stirred. Mix and put into a three-roll mill for grinding, dispersing, filtering, vacuum defoaming, and packaging to obtain a moisture-resistant high-reliability epoxy conductive silver paste.

Comparative example 1

The present comparative example provides a method for preparing a conductive silver paste, wherein the preparation method comprises the following steps:

The bisphenol F type epoxy resin was weighed in order: 15 parts by weight, epoxy-terminated polybutadiene rubber: 3 parts by weight, dicyandiamide: 1.6 parts by weight, organic urea (UR-500): 0.4 parts by weight, 1 , 4-butanediol diglycidyl ether: 2.0 parts by weight, polyamide wax: 0.3 parts by weight, KH-560 silane coupling agent: 0.3 parts by weight, TEGO-245: 0.2 parts by weight, and in a high-speed mixer Mixing it evenly to obtain a mixture A;

Then, 77.2 parts by weight of silver powder is added to the obtained mixture A in batches, and the mixture is further stirred and uniformly to obtain a conductive silver paste matrix;

Finally, the conductive silver gum substrate prepared above is thoroughly stirred, placed in a three-roll mill for grinding, dispersing, and then filtered, vacuum defoamed, and packaged to obtain the conductive silver paste.

Comparative example 2

The present comparative example provides a method for preparing a conductive silver paste, wherein the preparation method comprises the following steps:

The bisphenol F type epoxy resin was weighed in order: 13 parts by weight, epoxy-terminated polybutadiene rubber: 2 parts by weight, liquid aromatic amine: 4.0 parts by weight, 2-methyl-4-ethylimidazole: 0.7 weight , 1,4-butanediol diglycidyl ether: 2.0 parts by weight, polyamide wax: 0.3 parts by weight, KH-560 silane coupling agent: 0.3 parts by weight, TEGO-245: 0.2 parts by weight, and at high speed Mixing it evenly in the mixer to obtain a mixture A;

Then, 77.5 parts by weight of silver powder is added to the obtained mixture A in batches, and the mixture is further stirred and uniformly to obtain a conductive silver paste matrix;

Finally, the conductive silver gum substrate prepared above is thoroughly stirred, placed in a three-roll mill for grinding, dispersing, and then filtered, vacuum defoamed, and packaged to obtain the conductive silver paste.

Test case

In order to determine the working performance of the moisture-resistant high-reliability epoxy conductive silver paste prepared by the present invention, the moisture-resistant high-reliability epoxy conductive silver paste prepared in Examples 1-5 and the prepared ratios of Comparative Examples 1 and 2 are prepared. Conductive silver gel was tested and tested separately. The test items mainly included viscosity, viscosity after storage for 24 hours, thixotropic index, glass transition temperature, bond strength, volume resistivity and thermal decomposition temperature. The above viscosity and thixotropic index The glass transition temperature, bond strength, volume resistivity and thermal decomposition temperature are all measured by conventional techniques in the art. The relevant performance parameters are shown in Table 1.

Table 1

High temperature aging test: The standard reflow temperature commonly used in semiconductor packaging is 260 ° C, generally tested 3 times, each time about 15 seconds; in the examples of the present application, the high temperature aging experiment was carried out at 280 ° C, and the number of tests (5 times) More, each time duration (30s) is longer. It can be seen from Table 1 that the bonding strength of the conductive silver paste of the present application does not decrease significantly after experiencing more and more time of high temperature aging. High reliability.

Thermal shock test: The experimental temperature is -40 ° C -150 ° C, and the number of thermal shocks is 200. From the experimental results in Table 1, it can be seen that the thermal shock has little effect on the bond strength of the system.

High temperature, high humidity aging experiment: the experimental temperature is 85 ° C, the humidity is 85% RH, and the aging time is 168 h; as can be seen from Table 1, the conductive silver paste of the present application is bonded after high temperature and high humidity aging. The intensity is also basically unchanged. However, the conductive silver paste prepared in Comparative Example 1 and Comparative Example 2 showed a significant decrease in the bond strength after wet heat aging.

From Table 1, we can also find that the conductive silver paste prepared in Examples 1-5 of the present invention has a volume resistivity of the order of l0 ^-4 Ω/cm after curing at 150 ° C / 90 min.

In summary, the thermal shock has little effect on the bond strength of the system, and the bond strength does not decrease significantly after high temperature and damp heat aging. On the contrary, the bond strength of the conductive silver paste prepared by the individual examples is still certain. The degree of improvement indicates that the conductive silver paste prepared by the invention has high reliability, and has excellent working characteristics, and is suitable for bonding and fixing of semiconductor chips.

In addition, after storing the conductive silver paste prepared in Examples 1-5 and Comparative Example 1 and Comparative Example 2 for 24 hours, the viscosity of the above-mentioned conductive silver paste was measured, and the viscosity results are shown in Table 1, and the viscosity can be found by comparison. After 24 hours of storage, the viscosity of the conductive silver paste prepared in Comparative Example 2 was greatly increased; although the viscosity of the conductive silver paste prepared in Comparative Example 1 did not change, the operability of the conductive silver paste was poor due to the large viscosity. There are problems with drawing and silicone. The conductive silver paste prepared in Examples 1-5 of the present invention has a moderate viscosity, has substantially no change in viscosity after storage for 24 hours, and has a low viscosity at all times, which indicates that the conductive silver paste prepared by the present invention has good handleability. The storage is stable and has a long pot life, which can meet the application requirements of current semiconductor packages.

Claims (10)

1. An epoxy conductive silver paste, wherein the moisture-resistant high-reliability epoxy conductive silver paste is prepared from the following materials, based on 100% of the total weight of the moisture-resistant high-reliability epoxy conductive silver paste: 65-85 wt% metal silver powder, 5.0-30 wt% epoxy resin, 1-15 wt% active heterocyclic compound having a triazine structure, 0.5-10 wt% acrylic resin, 1.0-3.5 wt% curing agent, 0.05 - 1.5% by weight of a promoter and 0.01 to 3% by weight of a functional auxiliary;

   Preferably, the raw material further comprises 1-10% by weight of a toughening diluent;

   It is also preferred that the functional auxiliary comprises one or a combination of an antifoaming agent, a dispersing agent, a leveling agent, a coupling agent, and a thixotropic agent.
2. The silver paste according to claim 1, wherein the metallic silver powder is selected from the group consisting of one or a combination of spherical, flake, rod and dendritic metal silver powder;

   Preferably, the metal silver powder is a combination of a sheet metal silver powder and a spherical metal silver powder;

   It is also preferred that the metal silver powder has a size of from 0.1 to 10 μm, more preferably from 0.5 to 5 μm.
3. The silver paste according to claim 1, wherein the epoxy resin is selected from the group consisting of bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, hydantoin epoxy resin, 4,4'diaminodiphenylmethane tetraglycidylamine type epoxy resin, triglycidyl p-aminophenol type epoxy resin, 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester a combination of one or more of an epoxy resin, an alicyclic epoxy resin, and a novolac epoxy resin;

   Preferably, the alicyclic epoxy resin comprises 3,4-epoxycyclohexenemethyl-3,4-epoxycyclohexenoate, 4,5-epoxycyclohexane-1,2-dicarboxylic acid Diglycidyl ester or bis((3,4-epoxycyclohexyl)methyl) adipate.
4. The silver paste according to claim 1, wherein the active heterocyclic compound having a triazine structure is selected from the group consisting of 1,2,4-triazine, 1,3,5-triazine, 4-amino-1,3 , 5-triazin-2-one, 3-amino-5-phenyl-1,3,5-triazine, 2,4-diamino-6-phenyl-1,3,5-triazine, six Methylene diisocyanate trimer and its closure, toluene diisocyanate trimer and its closure, triglycidyl isocyanurate, triallyl isocyanurate and amino substituted benzotriazine derivatives One or a combination of several;

   Preferably, the active heterocyclic compound having a triazine structure comprises triglycidyl isocyanurate or triallyl isocyanurate.
5. The silver paste according to claim 1, wherein the acrylic resin is selected from the group consisting of an acrylate prepolymer, a polyfunctional acrylic resin, an epoxy modified acrylic resin, a urethane modified acrylic resin, and a silicone modified acrylic a combination of one or more of an enoate resin and a hyperbranched polyester modified acrylic resin;

   Preferably, the acrylate prepolymer has a functionality of ≥ 2 and a viscosity of ≤ 10000 mPas;

   It is also preferred that the polyfunctional acrylic resin comprises an acrylic resin having a number of acrylate groups of ≥ 2 and a viscosity of ≤ 10 Pas.
6. The silver paste according to claim 1, wherein the curing agent is selected from the group consisting of an imidazole curing agent, an imidazole modified curing agent, an aromatic amine curing agent, a dicyandiamide, and a dicyandiamide derivative curing agent. a combination of one or more of an organic acid hydrazide curing agent, a boron trifluoride-amine complex curing agent, and a microcapsule curing agent;

   Preferably, the imidazole curing agent comprises 2-methylimidazole, 2-phenylimidazole, 2-ethyl-4-methylimidazole or 1,2-dimethylimidazole;

   It is also preferred that the imidazole modified type curing agent comprises a cyanoethyl modified imidazole curing agent, a long alkyl chain modified imidazole curing agent, PN-23, PN-31, PN-40 or PN-50;

   More preferably, the cyanoethyl modified imidazole curing agent comprises 1-cyanoethyl-2-ethyl-4-methylimidazole or 1-cyanoethyl-2-phenylimidazole; The imidazole curing agent includes 2-heptadecylimidazole or 2,4-diamino-6-(2-undecylimidazolyl)-1-ethyltriazine;

   It is also preferred that the aromatic amine curing agent comprises 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfone, m-phenylenediamine, m-xylylenediamine or diethyltoluene. amine;

   Further preferably, the dicyandiamide derivative curing agent comprises a 3,5-disubstituted aniline modified dicyandiamide derivative, m-toluidine-modified dicyandiamide or benzoquinone-modified dicyandiamide;

   Further preferably, the organic acid hydrazide-based curing agent comprises succinic acid hydrazide, adipic acid dihydrazide, sebacic acid hydrazide, isophthalic acid hydrazide or p-hydroxybenzoic acid hydrazide;

   It is also preferred that the boron trifluoride-amine complex-based curing agent comprises a complex of boron trifluoride with ethylamine, piperidine, triethylamine or aniline.
7. The silver paste according to claim 1, wherein the promoter is selected from the group consisting of 2,4,6-tris(dimethylaminomethyl)phenol and 2,4,6-tris(dimethylaminomethyl)phenol. Tris(2-ethylhexanoic acid) salt, imidazole compound and salt complex thereof, triphenylphosphine, tetrabutylphosphonium bromide, tetrabutylphosphonium acetate, tetrabutylphosphine oxide, benzyltriphenyl bromide a combination of one or more of a metal salt of phosphine, 1-cyanoethyl-2-ethyl-4-methylimidazole, tetramethylguanidine, benzoyl peroxide, organic urea and acetylacetone;

   Preferably, the metal salt of acetylacetone comprises an aluminum salt of acetylacetone, a cobalt salt of acetylacetone, a zinc salt of acetylacetone, a copper salt of acetylacetone, a nickel salt of acetylacetone, a manganese salt of acetylacetone, and a chromium salt of acetylacetone. Acetyl A titanium salt of acetone or a zirconium salt of acetylacetone.
8. The silver paste according to claim 1, wherein the toughening diluent is selected from the group consisting of a carboxyl group liquid nitrile rubber, a hydroxyl group liquid nitrile rubber, a terminal amino liquid nitrile rubber, an end epoxy liquid nitrile rubber, Carboxyl-terminated liquid polybutadiene rubber, hydroxyl-terminated liquid polybutadiene rubber, epoxy-terminated polybutadiene rubber, liquid polyurethane, core-shell rubber particles, hyperbranched polyester, n-butyl glycidyl ether, l, 4-butanediol diglycidyl ether, trimethylolpropane glycidyl ether, glycerol triglycidyl ether, sterol glycidyl ether, ethylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, alkene Propyl glycidyl ether, phenyl glycidyl ether, benzyl glycidyl ether, 2-ethylhexyl glycidyl ether, C ₁₂ -C ₁₄ alkyl glycidyl ether, diethylene glycol glycidyl ether, p-tert-butyl A combination of one or more of glycidyl ether, cyclohexanediol diglycidyl ether, and resorcinol diglycidyl ether.
9. The method for preparing an epoxy conductive silver paste according to any one of claims 1 to 8, wherein the preparation method comprises the following steps:

   a, epoxy resin, toughening diluent, active heterocyclic compound with a triazine structure and acrylic resin are mixed uniformly to obtain a mixture A;

   b, sequentially adding a curing agent, a promoter and a functional auxiliary to the mixture A to obtain a colloid B;

   c. Adding metal silver powder to the colloid B, stirring uniformly, grinding, dispersing, filtering, vacuum defoaming, and packaging to obtain the moisture-resistant and high-reliability epoxy conductive silver paste.
10. The use of the epoxy conductive silver paste of any of claims 1-8 as a chip binder for electronic components and its use in electrode bonding.