JP2010059426A - Electroconductive adhesive and circuit using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electroconductive adhesive of excellent electrical conductivity, capable of bonding semiconductor elements and chip parts or discrete parts to printed wiring boards without causing any migrations. <P>SOLUTION: The electroconductive adhesive includes electroconductive particles and a resin. In this adhesive, 30 wt.% of more of the electroconductive particles is composed substantially of silver and tin, wherein the molar ratio of metal components of the electroconductive adhesive: silver/tin is (77.5:22.5) to (0:100). A circuit bonded using the electroconductive adhesive is also provided. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a conductive adhesive, and more particularly to a conductive adhesive that has excellent conductivity and can bond a semiconductor element, a chip component, or a discrete component to a printed wiring board without causing migration. The present invention also relates to a circuit in which a semiconductor element or the like is bonded using such a conductive adhesive.

  As one of semiconductor mounting technologies, there is a flip-chip bonding. There, a semiconductor element in which bumps are formed by solder plating is used, and the semiconductor element is joined by solder. In addition, bonding using a conductive adhesive using a noble metal powder such as silver, and bonding of electronic parts using an anisotropic conductive film using powder obtained by plating a resin ball with gold or the like have been attempted.

  On the other hand, also in the formation of a circuit using a printed wiring board, solder is used for joining chip parts and discrete parts. It is also practiced to mount these parts using a conductive adhesive instead of solder. However, when silver is used as the conductive particles in the adhesive, a conductive layer having excellent conductivity can be obtained, but migration may occur when a voltage is applied. (See IEEE Transaction on Components, Packaging and Manufacturing Technology, Part B, Vol. 17, No. 1, p83). Further, when tin plating or the like is performed, the adhesive strength is reduced due to the influence of high temperature.

  Currently, lead-tin alloy solder is used for joining electronic components. There is a public health problem where solder used in discarded electronic equipment dissolves in acid rain, dissolves in groundwater, and uses groundwater for drinking water. Therefore, there is a tendency to use solder having a higher melting point such as tin-silver and tin-zinc. However, in the method using solder, a cleaning agent may be used, which is not preferable in terms of work environment and safety.

  Nickel and nickel alloy powders are conductive particles that do not cause migration, but the conductive layer formed using them has a large specific resistance and is satisfactory because it has a higher specific resistance when exposed to high temperatures. It was not a thing.

  Japanese Patent Laid-Open No. 9-157613 discloses metal particles whose surfaces are nickel and / or nickel-boron alloy as conductive particles, polyoxyalkylene phosphate derivatives and polyoxyalkylene alkyl (or alkenyl) amines or derivatives thereof. By combining the conductive particles obtained by surface treatment with a mixture with an epoxy resin containing a reactive diluent, a conductive layer that does not cause migration and has stable conductivity even when exposed to high temperatures is obtained. It is disclosed that a conductive adhesive can be obtained. However, as a recent trend, there is a demand for a conductive adhesive that has higher conductivity and has a small increase in specific resistance even when processed under temperature conditions such that it adheres to high-temperature solder.

  Japanese Patent Application Laid-Open No. 11-80647 or Material stage, Vol. 1, No. 7, p. 51 2001 describes that fine particles of silver are bonded when heated at 200 ° C., indicating the development to a conductive adhesive. Yes. Since ultrafine silver is mainly used, the film thickness cannot be obtained, and migration occurs.

  An object of the present invention is to provide a conductive adhesive that does not cause migration even when a voltage is applied, has high conductivity, and can be used in place of solder in response to the above situation, and the conductive adhesion It is to provide a circuit using an agent.

  As a result of repeated studies to achieve this problem, the inventors of the present invention can achieve the above-mentioned problem by making silver-tin having a specific composition range present in the metal composition of the conductive adhesive. The fact that the composition range of the above-mentioned silver-tin did not cause migration even when silver powder was used in combination with tin, and found that metals were melted and connected by using fine metal powder together. Thus, the present invention has been completed.

SUMMARY OF THE INVENTION The conductive adhesive of the present invention is a conductive adhesive comprising conductive particles and a resin, wherein 30% by weight or more of the conductive particles are substantially composed of silver and tin, The silver: tin molar ratio is in the range of 77.5: 22.5 to 0: 100, and the circuit of the present invention uses the above-mentioned conductive adhesive to form a semiconductor element, A circuit in which chip parts, discrete parts, or combinations thereof are joined.

  The silver-tin powder consisting essentially of silver and tin used as conductive particles in the present invention is a characteristic component in the present invention, does not cause migration, and imparts high conductivity to the formed conductive layer. To do. The metal powder has a silver to tin molar ratio of 77.5: 22.5 to 0: 100, preferably 75:25 to 20:80. When the total number of both components is represented as 100, migration occurs when the silver molar ratio exceeds 77.5.

  The silver-tin powder may have any form as long as silver and tin atoms are present on the surface in the same powder particle, and it can be reduced from an aqueous solution of alloy powder or mixed salt. Examples thereof include a co-precipitated powder obtained by the precipitation method and a composite powder in which silver powder coated with the powder is formed into flakes by the stamp method and silver is present on the surface. Since homogeneous silver-tin powder is obtained and shows a stable effect, alloy powder is preferred. In addition, the effect of this invention can be acquired also with the mixed powder which only mixed silver powder and tin powder.

  Such a silver-tin alloy powder is, for example, mixed with silver in a desired molar ratio and melted, and then blown out from a nozzle into an argon atmosphere to form an alloy powder having a predetermined particle size or less. A method of collecting; a method in which the powder atomized in this way is further vaporized in a plasma furnace and then solidified by cooling to obtain an alloy powder; and a method in which the mixed powder is heated to form an alloy by any means. Obtainable.

  The shape of the silver-tin powder may be spherical or flake shaped, and other shapes such as needles or branches may be used. A mixture thereof may also be used.

  In the case of spherical powder, the average particle size is 0.1 to 10 μm because the system is kept stable in the state of adhesive, does not cause clogging in printing, and a highly conductive layer is obtained. In the case of flakes, the average diameter of the flat surface, that is, the average of the major axis and the minor axis is preferably 2 to 20 μm. The aspect ratio is usually 10 to 200, preferably 20 to 50.

  The silver-tin powder having such a composition is blended in the conductive particles by 95% by weight or less, preferably 90% by weight or less, more preferably 85% by weight or less. When the amount of the silver and tin is in the range of 77.5: 22.5 to 0: 100 in terms of the metal composition ratio in the adhesive, there is no conductive adhesive that can form a conductive layer with no migration and high conductivity. can get.

  In the present invention, in addition to the above silver-tin powder, other metal powder and / or carbon powder can be used in combination as the conductive particles. Examples of the metal powder that can be used in combination include silver powder, tin powder, bismuth powder or indium powder, or two or more kinds of alloy powders, co-precipitation powders and / or composite powders of these metals (hereinafter referred to as “alloy powders”). However, silver-tin powder having the composition of the above molar ratio is excluded.), And the alloy powder has a composition other than silver-tin bismuth powder, silver-tin indium powder and the above molar ratio. Silver-tin powder is exemplified. A fine particle conductive powder having a particle diameter of 5 to 60 nm, preferably 8 to 20 nm, is preferable.

  Examples of the carbon powder include carbon black, graphite, and mesophase thereof.

  The blending amount of these fine particle conductive powders is preferably 40% by weight to 2% by weight with respect to the metal powder having the above composition since low connection resistance can be obtained. When the content is 40% by weight or more, the viscosity of the paste increases, and the printing and dispensation are not good. If it is 2% by weight or less, there are few metal bonds and the connection resistance is high. The ultrafine particle conductive component can be produced by a known method. Examples include plasma and arc discharge methods.

  Among these, the metal powder that should be particularly noted is a fine conductive powder. Conventionally, silver powder has been thought to cause migration, but unexpectedly, by using the above silver-tin powder and silver powder together as conductive particles, migration does not occur and conductivity is excellent. A conductive adhesive that provides a layer can be obtained. Such silver powder is more preferably blended in an amount of 4 to 12% by weight based on the silver-tin powder having the above composition because excellent conductivity is obtained and there is no migration.

  Other metal powders of particular interest are tin powder, bismuth powder and silver-bismuth powder. By using tin powder, bismuth powder and / or silver-bismuth powder together with silver-tin powder having the above composition, metal bonding is performed by reaction of tin powder, silver-tin powder and bismuth at the curing temperature of the adhesive. And high conductivity is obtained. The blending amount of such tin powder, bismuth powder or silver-bismuth powder is more preferably in the range of 0.1 to 20% by weight with respect to the silver-tin powder having the above composition.

  The blending amount of the conductive particles in the conductive adhesive is preferably 60 to 98% by weight with respect to the total amount of the conductive particles and the resin, from the printability and the conductivity of the conductive layer obtained by curing. More preferred is -95% by weight.

  The conductive adhesive of the present invention contains a resin that functions as a binder in addition to the conductive particles. The resin may be a thermoplastic resin or a thermosetting resin. Examples of the thermoplastic resin include acrylic resin, ethyl cellulose, polyester, polysulfone, phenoxy resin, and polyimide. As thermosetting resins, amino resins such as urea resins, melamine resins, and guanamine resins; epoxy resins such as bisphenol A type, bisphenol F type, phenol novolac type, and alicyclic type; oxetane resins; resol type, novolac type Such phenol resins; silicone-modified organic resins such as silicone epoxy and silicone polyester are preferred. These resins may be used alone or in combination of two or more.

  Of these, epoxy resins and resol-type phenol resins are preferred, because even if an amount of resin that does not impair electrical conductivity is blended, excellent adhesiveness is obtained, and heat resistance is excellent, and bisphenol A type and Bisphenol F type epoxy resin is particularly preferred.

  When a resin that is liquid at room temperature is used as the resin, a vehicle can be obtained without using an organic solvent, and the drying step can be omitted. Examples of such a liquid resin include a liquid epoxy resin and a liquid phenol resin. Liquid epoxy resins include bisphenol A type epoxy resins having an average molecular weight of about 400 or less; branched polyfunctional bisphenol A type epoxy resins such as p-glycidoxyphenyldimethyltolyl bisphenol A diglycidyl ether; bisphenol F type Epoxy resin; phenol novolac type epoxy resin having an average molecular weight of about 570 or less; vinyl (3,4-cyclohexene) dioxide, 3,4-epoxycyclohexylcarboxylic acid (3,4-epoxycyclohexyl) methyl, bis (adipate) ( 3,4-epoxy-6-methylcyclohexylmethyl), 2- (3,4-epoxycyclohexyl) 5,1-spiro (3,4-epoxycyclohexyl) -m-dioxane Epoxy resin Glycidyl ester type epoxy resin comprising at least one of diglycidyl hexahydrophthalate, diglycidyl 3-methylhexahydrophthalate and diglycidyl hexahydroterephthalate; diglycidyl aniline, diglycidyl toluidine, triglycidyl-p-aminophenol, Glycidylamine type epoxy resin comprising at least one of tetraglycidyl-m-xylylenediamine and tetraglycidylbis (aminomethyl) cyclohexane as a constituent; and 1,3-diglycidyl-5-methyl-5-ethylhydantoin as a constituent Hydantoin type epoxy resin is exemplified.

  In addition, the liquid resin may be mixed with a resin that is compatible within the range in which the mixed system exhibits fluidity and exhibits a solid or ultra-high viscosity at room temperature. Bisphenol A type epoxy resin, diglycidyl biphenyl, novolac epoxy resin, epoxy resin such as tetrabromobisphenol A type epoxy resin; and novolak phenol resin.

  In the case of an epoxy resin, the curing mechanism may be a self-curing resin, or a curing agent or curing accelerator such as amines, imidazoles, acid anhydrides or onium salts may be used. The resin may function as a curing agent for the epoxy resin.

  A typical epoxy resin used in the present invention is cured by a phenol resin. The phenol resin may be an initial condensate of a phenol resin that is usually used as a curing agent for an epoxy resin, and may be a resol type or a novolac type. However, stress during curing is relieved and excellent heat cycle resistance is obtained. Therefore, it is preferable that 50% by weight or more is an alkylresole type or alkyl novolac type phenol resin. In the case of an alkyl resole type phenol resin, the average molecular weight is preferably 2,000 or more in order to obtain excellent printability. In these alkylresole type or alkyl novolac type phenol resins, alkyl groups having 1 to 18 carbon atoms can be used, such as ethyl, propyl, butyl, pentyl, hexyl, octyl, nonyl, and decyl groups. Those having 2 to 10 carbon atoms are preferred.

  The amount of the phenol resin used as the curing agent for the epoxy resin varies depending on the type of the epoxy resin and the phenol resin, but in order to obtain excellent stability at a high specific resistance after curing, the weight of the epoxy resin and the phenol resin. The ratio is preferably in the range of 4: 1 to 1: 4, more preferably 4: 1 to 1: 1.

  The blending amount of the resin in the conductive adhesive is preferably 2 to 40% by weight, based on the printability and the conductivity of the conductive layer obtained by curing, with respect to the total of the resin and the conductive particles. More preferred is weight percent.

  The conductive paste of the present invention is prepared to have an appropriate viscosity according to the method of printing or applying to an element, a substrate, etc. by selecting the type and amount of conductive particles and resin, and using a diluent as necessary. can do. For example, when used for screen printing, the apparent viscosity of the conductive paste at room temperature is preferably 10 to 500 Pa · s, and more preferably 15 to 300 Pa · s. As the diluent, an organic solvent, and in particular, when the resin is an epoxy resin, a reactive diluent can be used.

  The organic solvent is selected according to the type of resin. Organic solvents include aromatic hydrocarbons such as toluene, xylene, mesitylene, and tetralin; ethers such as tetrahydrofuran; ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and isophorone; 2-pyrrolidone, 1-methyl Lactones such as 2-pyrrolidone; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, and the corresponding propylene glycol derivatives Ether alcohols; corresponding esters such as acetates; and malonic acid, succinic acid, etc. Methyl esters of dicarboxylic acids, diesters, such as ethyl esters are exemplified. The amount of the organic solvent used is arbitrarily selected depending on the type and amount ratio of the conductive particles and resin used, the method of printing or applying the conductive paste, and the like.

  The conductive adhesive of the present invention is provided with appropriate fluidity in order to form an arbitrary pattern by printing or coating or to be filled in details, and also prevents deterioration of the meat due to the volatilization of the solvent and deterioration of the working environment. If necessary, it is preferable to use a reactive diluent as part or all of the diluent. Examples of reactive diluents include polyethylene glycol diglycidyl ether, poly (2-hydroxypropylene) glycol diglycidyl ether, polypropylene glycol diglycidyl ether, butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, diglycidyl aniline, 1, Diglycidyl compounds such as 4-cyclohexanedimethanol diglycidyl ether, 1,3-bis (3-glycidoxypropyl) -1,1,3,3-tetramethyldisiloxane; and trimethylolpropane triglycidyl ether, glycerin Examples include triglycidyl compounds such as triglycidyl ether, and n-butyl glycidyl ether, allyl glycidyl ether, glycidyl methacrylate, etc. Monoglycidyl ether type reactive diluents are glycidyl acrylate, may be used in combination monoglycidyl ester type reactive diluent such as glycidyl methacrylate. When only a reactive diluent is used without using an organic solvent as a diluent, these can be polymerized and cured under suitable conditions and incorporated into the conductive layer instead of removing the solvent.

  In addition to the conductive adhesive of the present invention, if necessary, an aluminum chelate compound such as diisopropoxy (ethylacetoacetate) aluminum; a titanium such as isopropyltriisostearoyl titanate as a dispersion aid. An acid ester; an aliphatic polyvalent carboxylic acid ester; an unsaturated fatty acid amine salt; a surfactant such as sorbitan monooleate; or a polymer compound such as a polyesteramine salt or polyamide may be used. Moreover, you may mix | blend an inorganic and organic pigment, a silane coupling agent, a leveling agent, a thixotropic agent, an antifoamer, etc.

  The conductive adhesive of the present invention can be prepared by uniformly mixing the blending components by a mixing means such as a raking machine, a propeller stirrer, a kneader, a roll, a pot mill and the like. Preparation temperature is not specifically limited, For example, it can prepare at normal temperature.

  The conductive adhesive of the present invention can be printed or applied to a substrate by any method such as screen printing, gravure printing, dispensing, or the like. In the case of using an organic solvent, the solvent is volatilized after printing or application at room temperature or by heating. When the conductive adhesive of the present invention is used without a diluent or only a reactive diluent as a diluent, the above solvent removal step is not necessary. Next, the resin is usually cured by heating at 70 to 250 ° C., for example, an epoxy resin using a phenol resin as a curing agent, at 150 to 200 ° C. for 2 to 30 minutes, depending on the type of resin and curing agent or curing catalyst. Thus, a conductive circuit can be formed on a necessary portion of the substrate surface.

  In this manner, a circuit in which one or more of a semiconductor element, a chip component, and a discrete component are bonded can be formed on the substrate surface using the conductive adhesive of the present invention.

  The conductive adhesive of the present invention is tin-plated, solder-plated, palladium-plated, silver-palladium terminal electrode chip parts, tin-plated, solder-plated, semiconductor elements plated with palladium, a copper-clad board, nickel on gold, gold The conductive adhesive of the present invention is heated and bonded to a ceramic substrate obtained by printing and baking a silver, copper, and silver palladium paste on a ceramic substrate. At this time, conductive particles of 5 to 100 nm and spherical or scaly conductive powder are fused and bonded. At this time, silver fuses with tin to form a silver-tin alloy. In order to lower the fusion temperature, bismuth, indium, and alloy powders containing these metals can also be used in combination. The bonded adhesive contains a silver-tin alloy and does not cause migration.

  Hereinafter, the present invention will be described in more detail with reference examples, examples and comparative examples. The present invention is not limited by these examples. In these examples, parts indicate parts by weight.

Reference Example 1-Production of silver-tin alloy powder A mixed powder obtained by mixing silver powder and tin powder so as to have a molar ratio shown in Table 1 was melted in a melting apparatus provided with a nozzle, and the alloy was discharged from the nozzle. By spraying into an argon atmosphere having a temperature lower than the melting point, fine powder was obtained. This was classified to produce spherical silver-tin alloy powder having an average particle size shown in Table 1.

In addition to the above silver-tin alloy powder, the following metal powder was used.
Silver powder, flakes, average particle size 10 μm;
Bismuth powder, spherical, average particle size 15 μm;
Silver-bismuth powder, alloy powder with a molar ratio of Ag: Bi of 5: 1, spherical, average particle size 15 μm;
Silver-indium powder, alloy powder of 5: 1 molar ratio of Ag: In, spherical, average particle size 20 μm;
Tin powder, spherical, average particle size 15μm

Examples 1-8, Comparative Example 1
Using three rolls, blend the conductive particles shown in Table 2, the bisphenol A type epoxy resin having an average molecular weight of 900 and the resol type alkylphenol resin, and mix until uniform, then add 2-ethyl-4-methylimidazole And mixed. The mixture was transferred to a kneader, diethylene glycol monobutyl ether was added with mixing so that the apparent viscosity of the system at 25 ° C. was 150 Pa · s, and mixing was continued to prepare a conductive adhesive. In either case, the total blending amount of the conductive particles is 85 parts and the blending amount of the resin is 15 parts. However, as the conductive particles, the adhesive of Comparative Example 1 uses only silver powder.

(1) Production of Circuit Sample The conductive adhesive obtained as described above was stencil-printed on the copper surface of a copper-clad glass epoxy circuit board using a metal mask having a thickness of 75 μm. A tin-plated 2012-size chip resistor was pressure-bonded and heated at 150 ° C. for 30 minutes to cure the adhesive, thereby connecting the chip resistor to the circuit board to produce a circuit sample. .

(2) Measurement of connection resistance The connection resistance of the circuit sample was measured.

(3) Measurement of adhesive strength Adhesive strength is measured by pushing the adhesive part of the circuit sample from the side with a push-pull gauge (manufactured by Maruhishi Kagaku Kikai Seisakusho Co., Ltd., PGD II type) and reading the numerical value to measure the force required for peeling. (Initial value).

A similar circuit sample is shown below:
Standing at 150 ° C. for 30 minutes Standing at 85 ° C. and 85% RH for 30 minutes After leaving the cycle for 30 minutes at −40 ° C. for 1,000 cycles, the adhesive strength was measured in the same manner.

(4) Migration test The adhesive composition prepared as described above was screen-printed on a ceramic substrate and cured by heating at 150 ° C. for 30 minutes to produce a counter electrode having a line spacing of 2 mm. A voltage of 10 V was applied between the electrodes, one drop of ion exchange water and one electrode were dropped between the electrodes, and the time when the current flowed 100 mA was defined as the migration time.

  The above results are summarized in Table 2.

  As is clear from Table 2, the sample obtained from the conductive adhesive of Comparative Example 1 showed significant migration and markedly decreased adhesive strength after the heat cycle test. On the other hand, the sample obtained from the conductive adhesive of the present invention showed not only excellent connection resistance and adhesive strength, but also little migration, and almost no decrease in adhesive strength after the heat cycle test. .

Reference Example 2 Production of Silver-Tin Alloy Powder A mixed powder obtained by mixing silver powder and tin powder so as to have a molar ratio shown in Table 3 was melted in a melting apparatus provided with a nozzle. Fine powder was obtained by jetting into an argon atmosphere at a temperature lower than the melting point. This was classified to produce spherical silver-tin alloy powder having an average particle size shown in Table 3.

Reference Examples 3-6 Ultrafine silver powder, tin powder, bismuth powder, copper powder, silver tin alloy powder When the metal powder passes through the plasma discharge in an argon atmosphere, it evaporates and is made into ultrafine powder in a repair tank. It was. The alloy powder was melted and sprayed in advance to prepare a powder in the vicinity of 50 μm. This powder was vaporized in an argon atmosphere.

  In addition to the above silver-tin alloy powder, the following metal powder was used.

  Table 3 shows the particle diameter of spherical silver powder, flaky silver powder, and spherical tin powder.

Examples 9-19, Comparative Examples 2-5
Using three rolls, the conductive particles shown in Table 3, the average molecular weight 900 bisphenol A type epoxy resin (average molecular weight: 380) and the resol type alkylphenol resin (average molecular weight: 3400) were changed to epoxy resin: phenol resin = 10: 5. After blending at a ratio of (weight ratio) and mixing until uniform, 2-ethyl-4-methylimidazole was added and mixed. The mixture was transferred to a kneader, diethylene glycol monobutyl ether was added with mixing so that the apparent viscosity of the system at 25 ° C. was 150 Pa · s, and mixing was continued to prepare a conductive adhesive. In any case, the total blending amount of the conductive particles is 85 parts by weight, and the blending amount of the resin is 15 parts by weight. However, the adhesive of Comparative Example 2 uses only silver powder as the conductive particles, and the adhesive of Comparative Example 3 is obtained by replacing part of the silver powder with 10 nm fine powder. Connection resistance decreases, but migration is bad. Comparative Example 4 is an example using silver-tin alloy powder, but the connection resistance is high because the particle size is large and there is no metal fusion. Comparative Example 5 uses conventional lead-tin eutectic solder.

(1) Production of Circuit Sample A circuit sample was produced in the same manner as in Examples 1 to 8 using the conductive adhesive obtained as described above.

(2) Measurement of connection resistance The connection resistance of the circuit sample was measured.

(3) Measurement of adhesive strength Adhesive strength was measured in the same manner as in Examples 1-8.

(4) Migration test The migration time was measured in the same manner as in Examples 1-8.

  The above results are summarized in Table 3.

  As can be seen from Table 3, the samples obtained from the conductive adhesives of Comparative Examples 2 and 3 showed significant migration and significantly reduced adhesive strength after the heat cycle test. On the other hand, the sample obtained from the conductive adhesive of the present invention showed not only excellent connection resistance and adhesive strength, but also little migration, and almost no decrease in adhesive strength after the heat cycle test. .

  When the adhesive layer after heat curing was observed, crystals of silver 3 tin could be observed except in Example 15. It is considered that migration can be prevented by the formation of this stable crystal.

  The conductive adhesive of the present invention is printed or coated on a substrate and cured to cause no migration, has high conductivity, can be used instead of solder, or is in contact with molten high melting point solder. Thus, it is possible to form a conductive layer in which the specific resistance hardly changes even when exposed to high temperatures, and in which the specific resistance does not increase due to corrosion caused by the presence of moisture at high temperatures.

  Taking advantage of such advantages, the conductive adhesive of the present invention is extremely useful for bonding and mounting of semiconductors and electronic components, and can be used to advantageously form microelectronic circuits.

Claims (12)

  In the conductive adhesive containing the conductive particles and the resin, 30% by weight or more of the conductive particles are substantially composed of silver and tin, and the molar ratio of silver: tin of the metal component of the conductive adhesive is 77.5: 22. A conductive adhesive in the range of 0.5 to 0: 100.   The conductive adhesive according to claim 1, wherein the conductive particles are silver-tin alloy powder, mixed powder of silver powder and tin powder, or mixed powder of silver-tin alloy powder, silver powder and tin powder.   The conductive particles further include spherical powder having an average particle diameter of 0.1 to 10 μm and / or flake powder having an average flat plane diameter of 2 to 20 μm and silver, tin, silver tin, bismuth having an average diameter of 5 to 60 nm, The conductive adhesive according to claim 1 or 2, comprising at least one metal powder selected from the group consisting of copper or two or more kinds of these alloy powders. Further, as the conductive particles, silver powder, tin powder, copper powder, bismuth powder or indium powder, or two or more alloy powders and / or mixed powders of these metals, provided that the composition has a molar ratio according to claim 1. Except silver-tin powder having
The conductivity according to any one of claims 1 to 3, wherein the metal powder is contained in an amount of 25% by weight or less with respect to the metal powder according to claim 1 and the particle diameter is 5 to 50 nm. adhesive.   The conductive adhesive according to any one of claims 1 to 4, wherein 40% by weight or more of the conductive particles of the conductive adhesive is substantially composed of silver and tin.   The conductive adhesive according to any one of claims 1 to 5, wherein the molar ratio of silver: tin of the metal component of the conductive adhesive is in the range of 75:25 to 20:80.   6. The molar ratio of silver: tin of the metal component of the conductive adhesive is in the range of 62.5: 37.5 to 77.5: 22.5. The conductive adhesive as described.   The electroconductive adhesive agent which contains 4-12 weight% silver powder with respect to the silver-tin powder of Claim 7 as electroconductive particle.   The electroconductive adhesive agent which contains 0.1-20 weight% bismuth powder and / or silver-bismuth powder with respect to the silver-tin powder of Claim 7 as electroconductive particle.   A circuit in which a semiconductor element, a chip component, a discrete component, or a combination thereof is bonded using the conductive adhesive according to any one of claims 1 to 9.   The composition of the adhesive connected by the conductive adhesive according to any one of claims 1 to 9 is alloyed with a metal of a semiconductor element, a chip component, a terminal electrode of a discrete component, and a land portion of a substrate. Circuit with connections.   A circuit in which a silver-tin alloy is contained in a metal in the alloyed connection structure according to claim 11.