JP2020076040A - Method for producing conductive filler, conductive addition reaction curable type silicone composition, and semiconductor device - Google Patents

Abstract

To provide a method for producing a conductive filler which does not impair storage stability and thermal stability of a cured product when being blended with a curable silicone composition, etc., a conductive curable silicone composition excellent in storage stability before curing and thermal stability of a cured product, and a semiconductor device excellent in reliability.SOLUTION: There are provided a method for producing a conductive filler that surface-treats conductive particles having a surface coated with an aliphatic acid with an epoxy group-containing organoalkoxysilane, and further treats the conductive particles with organosilazane; a conductive addition reaction curable type silicone composition composed of the conductive filler and an addition reaction curable type silicone composition; and a semiconductor device in which a semiconductor element is coated with a cured product of the conductive addition reaction curable type silicone composition.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for producing a conductive filler, a conductive addition reaction curable silicone composition, and a semiconductor device.
Specifically, the surface of the conductive particles coated with a fatty acid is treated with an epoxy group-containing organoalkoxysilane, and further treated with an organosilazane, a method for producing an electrically conductive filler, containing the electrically conductive filler thus produced. And a semiconductor device in which a semiconductor element is coated with a cured product of the conductive addition reaction-curable silicone elastomer composition.

A liquid silicone elastomer composition containing a thermally conductive, electrically conductive inorganic or metal-based thermally conductive, electrically conductive filler is used as an adhesive, potting agent, protective coating agent for electric / electronic parts. Has been done. Liquid organopolysiloxane having a silicon atom-bonded alkenyl group, liquid organopolysiloxane having a silicon atom-bonded hydrogen atom, addition reaction catalyst, thermal conductivity, and addition reaction curable liquid silicone composition containing conductive filler as essential components Are disclosed in, for example, Japanese Patent Application Laid-Open Nos. 2-97559 and 2-41362. Since such a liquid silicone elastomer composition is cured into a low-stress elastomer excellent in heat resistance, thermal conductivity, and conductivity, it is used as an adhesive, potting agent, protective coating agent for electric / electronic parts. It is used as an adhesive for semiconductor devices and heat sinks. The metallic particulate filler such as silver is excellent not only in thermal conductivity but also in electrical conductivity.

Such a heat conductive and conductive silicone elastomer composition has a heat conductive and conductive addition reaction curable organopolysiloxane composition containing a large amount of silver particles in order to further improve the heat conductive and conductive properties. It has been proposed (JP-A-2-238054). The cured product of this composition has excellent thermal conductivity and conductivity, but commercially available silver particles have residual organic substances such as fatty acids as a dispersant (coating agent) for preventing aggregation during production. The surface is in a state of being treated or coated with the organic substance. When such a silver particle is blended with a silicone elastomer composition, the cured product thereof has improved thermal conductivity and conductivity, but its thermal stability is remarkably lowered, and the reliability of a semiconductor device using the same is remarkably improved. There is a problem of decrease.

Therefore, in order to improve the thermal stability of the cured product, the silver particles whose surface is treated or coated with an organic substance such as a fatty acid are further treated or coated with an epoxy group-containing compound and a curing agent for an epoxy resin. A polymerizable filler has been proposed (JP 2004-83905 A). However, the present inventor has noticed that the liquid or paste-like conductive silicone elastomer composition containing this conductive filler has a problem that storage stability (pot life) is extremely low.

JP-A-2-97559 JP-A-2-41362 JP-A-2-238054 JP 2004-83905 A

As a result of intensive studies on the above problems, the present inventors have found that conductive particles whose surfaces are coated with a fatty acid have been surface-treated with an epoxy group-containing organoalkoxysilane, and that the conductive particles have been treated with an organosilazane. If so, they have found that there is no such problem and arrived at the present invention.

An object of the present invention is that when added to a liquid or paste addition reaction curable silicone composition, the viscosity increase during storage is small and storage stability is excellent, and moreover, the heat resistance stability of the cured product of the composition is high. Method for producing excellent conductive filler, conductive addition reaction curable silicone composition having excellent thermal stability of a cured product of a curable silicone composition containing the conductive filler, and a semiconductor device using the composition An object of the present invention is to provide a semiconductor device which is coated and cured and has excellent reliability.

This problem is achieved by the following.
[1] A method for producing a conductive filler, characterized in that conductive particles having a surface coated with a fatty acid are surface-treated with an epoxy group-containing organoalkoxysilane, and further treated with an organosilazane.
[1-1] The epoxy group-containing organoalkoxysilane is the epoxy group-containing organoalkoxysilane itself or an organic solvent solution thereof, and the organosilazane is the organosilazane itself or an organic solvent solution thereof, [1] A method for producing the conductive filler described.
[1-2] The method for producing a conductive filler according to [1-1], wherein the organic solvent for the epoxy group-containing organoalkoxysilane is anhydrous alcohol.
[1-3] The epoxy group-containing organoalkoxysilane is partially hydrolyzed and condensed, and the partially hydrolyzed condensate film covers the conductive particles whose surface is coated with a fatty acid. The method for producing a conductive filler according to [1-2].
[1-4] The method for producing a conductive filler according to [1], [1-2] or [1-3], wherein the treatment with organosilazane is a hydrophobic treatment.
[2] The surface treatment of the conductive particles whose surface is coated with a fatty acid with the epoxy group-containing organoalkoxysilane is carried out by conducting the conductive particles whose surface is coated with a fatty acid and the epoxy group-containing organoalkoxysilane itself or an organic solvent solution thereof. The method for producing a conductive filler according to claim 1, which comprises mixing and separating the surface-treated conductive particles from the mixture.
[3] The conductive particles are conductive metal particles, the epoxy group-containing organoalkoxysilane is glycidoxyalkyltrialkoxysilane or 2- (3,4-epoxycyclohexyl) alkyltrialkoxysilane, and the organosilazane is hexa. It is organodisilazane, The manufacturing method of the electroconductive filler as described in [1] or [2] characterized by the above-mentioned.
[3-1] The conductive particles are conductive metal particles, the epoxy group-containing organoalkoxysilane is glycidoxyalkyl (methyl) dialkoxysilane, and the organosilazane is hexaorganodisilazane. The method for producing a conductive filler according to [1] or [2].
[4] The conductive metal particles are silver particles, the glycidoxyalkyltrialkoxysilane is 3-glycidoxypropyltrimethoxysilane or 3-glycidoxypropyltriethoxysilane, and the hexaorganodisilazane is hexamethyl. It is disilazane, The manufacturing method of the electroconductive filler as described in [3] characterized by the above-mentioned.

[5] Conductive addition characterized in that conductive particles having a surface coated with a fatty acid are surface-treated with an epoxy group-containing organoalkoxysilane and further contain conductive particles treated with an organosilazane. Reaction-curable silicone composition.
[5-1] The conductive addition reaction-curable silicone composition according to [5], wherein the conductive particles are contained in the composition in an amount of 30 to 95% by mass.
[5-2] The conductive addition reaction-curable silicone composition according to [5] or [5-1], wherein the conductive addition reaction-curable silicone composition is a conductive addition reaction-curable silicone elastomer composition.
[5-3] The surface treatment with the epoxy group-containing organoalkoxysilane is a coating with a partial hydrolysis-condensation product of the epoxy group-containing organoalkoxysilane, and the treatment with the organosilazane is a hydrophobic treatment. The conductive addition reaction-curable silicone composition according to [5], [5-1] or [5-2].
[6] The conductive particles are conductive metal particles, the epoxy group-containing organoalkoxysilane is glycidoxyalkyltrialkoxysilane or 2- (3,4-epoxycyclohexyl) alkyltrialkoxysilane, and the organosilazane is hexa. The conductive addition reaction curable silicone composition according to [5], [5-1], [5-2] or [5-3], which is an organodisilazane.
[7] The conductive metal particles are silver particles, the glycidoxyalkyltrialkoxysilane is 3-glycidoxypropyltrimethoxysilane or 3-glycidoxypropyltriethoxysilane, and the hexaorganodisilazane is hexamethyl. The conductive addition reaction-curable silicone composition according to [6], which is disilazane.
[8] Addition reaction curable silicone composition constituting the conductive addition reaction curable silicone composition has a liquid organopolysiloxane (A) having at least two silicon atom-bonded alkenyl groups in one molecule, and (B) silicon. The electroconductive material according to any one of [5] to [7], which comprises a liquid organopolysiloxane having at least two atom-bonded hydrogen atoms in one molecule and (C) a catalyst for addition reaction. Addition reaction curable silicone composition.
[9] The conductive addition reaction curable silicone composition according to [8], which further contains (D) an addition reaction control agent and (E) an adhesiveness-imparting agent.

[10] A conductive addition reaction curable silicone elastomer composition in which conductive particles having a surface coated with fatty acid are surface-treated with an epoxy group-containing organoalkoxysilane and further containing conductive particles treated with an organosilazane. A semiconductor device, wherein a semiconductor element is covered with a cured product.
[11] The semiconductor device according to [10], wherein the semiconductor element is bonded to a heat dissipation plate through a cured product of the conductive addition reaction-curable silicone elastomer composition according to [10]. ..

According to the method for producing a conductive filler of the present invention, a conductive filler capable of imparting excellent conductivity and storage stability to a non-curable silicone composition and a curable silicone composition can be easily and efficiently produced. can do.
The conductive addition reaction-curable silicone composition containing the conductive filler produced by the production method of the present invention has excellent storage stability and thus does not increase in viscosity during storage, and the cured product has thermal stability. Is effective. Further, the semiconductor device of the present invention has an effect of having excellent reliability because the semiconductor element is coated with the cured product of the conductive addition reaction-curable silicone elastomer composition.

3 is a cross-sectional view of an LSI that is an example of the semiconductor device of the present invention.

The method for producing a conductive filler of the present invention is characterized in that conductive particles having a surface coated with a fatty acid are surface-treated with an epoxy group-containing organoalkoxysilane, and further treated with an organosilazane.

The material of the conductive particles may be any material having excellent conductivity, such as metals such as gold, silver, copper, palladium, aluminum, nickel, tin and alloys thereof; silica, glass, silicon nitride, boron nitride, Inorganic substances such as silicon carbide; metal compounds such as aluminum nitride, alumina, titanium oxide, aluminum hydroxide and aluminum sulfide are exemplified, but silver particles are preferable in terms of conductivity. The silver particles may be any of reduced silver, atomized silver, electrolytic silver and the like, but reduced silver particles produced by a metal salt reduction method, particularly a wet reduction method are preferable. Metal particles such as silver particles have excellent electrical conductivity and thermal conductivity.

Examples of the shape of the conductive particles include spherical, granular, teardrop-shaped, flake-shaped, plate-shaped, fibrous, columnar, crushed, and coil-shaped, but spherical, granular, teardrop-shaped, or flake-shaped. Is preferred. The average particle diameter is not limited as long as it is in the form of fine particles, but is not limited, but the average particle diameter (median diameter D50) is preferably 0.01 to 50 μm, and more preferably 0.1 to 5 μm.
If the average particle size exceeds 50 μm, the conductivity of the conductive addition reaction curable silicone composition of the present invention may not be sufficiently obtained, and if it is less than 0.01 μm, the surface activity is too strong and the storage stability is low. This is because there is a risk that it will decrease.
The average particle size is a volume-based cumulative 50% value of the particle size distribution measured by using a laser diffraction / scattering particle size distribution measuring device, that is, a median diameter (D50 value).

The fatty acid coating the surface of the conductive particles is not particularly limited, and may be a saturated fatty acid or an unsaturated fatty acid, but in terms of dispersibility, the number of carbon atoms is preferably 6 or more, and 16 or more. More preferable. Examples of fatty acids having 6 or more carbon atoms include caproic acid, caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, and linoleic acid. In addition, a polycarboxylic acid may be used in combination unless it is against the purpose.

When the conductive metal particles are produced by a wet reduction method of a metal salt, fatty acids are usually added during the production process in order to prevent aggregation, so that the reduced metal particles (eg, reduced silver particles) are fatty acids. It is coated (for example, JP-A No. 54-112270).
Even when the fatty acid is not added during the production by the wet reduction method, or when the fatty acid is added and the reduced metal particles are coated with the fatty acid, the reduced metal particles produced in such a manner (eg, reduced silver) Fatty acids may be added later to the particles).
The post-addition method is a method in which a liquid or powdery fatty acid is directly mixed with reduced metal particles (eg, reduced silver particles), or a fatty acid is dissolved in a volatile solvent in which the reduced silver particles are added. A method of removing the volatile solvent after the addition is exemplified. Further, when the conductive metal particles are flaky, when the conductive metal particles are flaked by a ball mill or the like, a fatty acid that is a lubricant or a lubricant may be added to prevent the particles from aggregating. It is being appreciated. Examples of the addition method include a method of adding a liquid fatty acid in the form of a liquid, powder or a volatile solvent.

In the method for producing conductive particles according to the first aspect, first, the conductive particles whose surface is coated with a fatty acid are surface-treated with an epoxy group-containing organoalkoxysilane. The epoxy group-containing organoalkoxysilane has 3 or 2 alkoxy groups bonded to a silicon atom. Examples of the alkoxy group include lower alkoxy groups such as a methoxy group, an ethoxy group, a propoxy group and a butoxy group. Particularly, a methoxy group having excellent reactivity and then an ethoxy group are preferable. Further, the epoxy group is preferably an epoxy group in a glycidoxyalkyl group (preferably a glycidoxypropyl group).

Examples of such an epoxy group-containing organoalkoxysilane include glycidoxyalkyltrialkoxysilane, glycidoxypropyl (methyl) dialkoxysilane, and 2- (3,4-epoxycyclohexyl) alkyltrialkoxysilane. Examples of glycidoxyalkyltrialkoxysilane include 3-glycidoxypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane, and glycidoxypropyl (methyl) dialkoxysilane includes 3-glycidoxypropyl (methyl). ) Dimethoxysilane is exemplified, and 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane is exemplified as 2- (3,4-epoxycyclohexyl) alkyltrialkoxysilane, and 3-glycidoxypropyltrimethoxysilane is exemplified. Silane and 3-glycidoxypropyltriethoxysilane are preferred.

As described above, the conductive filler of the present invention can be produced by surface-treating conductive particles having a surface coated with a fatty acid with an epoxy group-containing organoalkoxysilane, and further by treating with organosilazane. ..
In order to surface-treat conductive particles whose surface is coated with a fatty acid with an epoxy group-containing organoalkoxysilane, the epoxy group-containing organoalkoxysilane is usually a liquid at room temperature, and therefore the epoxy group-containing organoalkoxylane itself or its The conductive particles having a surface coated with a fatty acid are immersed in an organic solvent solution, stirred well, and then allowed to stand to take out the separated conductive particles. Alternatively, the epoxy group-containing organoalkoxysilane itself or a solution thereof in an organic solvent is thoroughly mixed with conductive particles having a surface coated with a fatty acid, and the mixture is allowed to stand to take out the conductive particles that have been precipitated and separated.

The organic solvent for dissolving the epoxy group-containing organoalkoxylane is preferably liquid at room temperature and volatile. Alcohol (eg, ethanol, propanol), ketone (eg, acetone, methyl ethyl ketone), ester (eg, ethyl acetate), aliphatic hydrocarbon solvent (eg, octane, cyclohexane), aromatic hydrocarbon solvent (eg, toluene) , Xylene) are exemplified.
When ethanol is used as the organic solvent for dissolving the epoxy group-containing organoalkoxylane, even the absolute ethanol (99.5% by volume or more) of the Japanese Pharmacopoeia contains a trace amount (for example, 0.1% by volume) of water. Therefore, the epoxy group-containing organoalkoxylane is partially hydrolyzed to form a partially hydrolyzed condensate, which adheres to the surface of the conductive particles whose surface is coated with the fatty acid. The conductive particles whose surface is coated with fatty acid are coated with a partially hydrolyzed condensate film of an epoxy group-containing organoalkoxylane.
As a result, anhydrous ethanol is a preferable organic solvent because the surface treatment effect is improved. The water content of anhydrous ethanol is preferably 0.05 to 0.3% by volume.

Epoxy group-containing organoalkoxylane itself or an organic solvent solution thereof, a step of immersing the conductive particles whose surface is coated with a fatty acid, and stirring, or the epoxy group-containing organoalkoxylane itself or an organic solvent solution thereof, the surface is The step of mixing with the conductive particles coated with the fatty acid may be carried out at room temperature in the air atmosphere, or may be carried out by heating to about 40 to 100 ° C. The stirring time and mixing time are preferably 5 minutes to 10 hours.
The conductive particles taken out by sedimentation are preferably dried by air drying or vacuum drying, and rinsed with a clean organic solvent before drying to remove excess epoxy group-containing organoalkoxysilane attached to the surface. May be removed.

The conductive particles whose surface is coated with a fatty acid and which has been surface-treated with an epoxy group-containing organoalkoxysilane are further treated with an organosilazane.
Organosilazane is a general term for organosilicon compounds having a Si—N bond in the molecule, and organodisilazane and organotrisilazane are preferred. Hexamethyldisilazane, sym-tetramethyldivinyldisilazane, octamethyltrisilazane, and hexamethylcyclotrisilazane are exemplified, but hexamethyldisilazane is preferable from the viewpoint of reactivity and availability.

In particular, hexamethyldisilazane is a well-known trimethylsilyl group donor, and compounds having active hydrogen (for example, silanol group-containing compounds, carboxylic acids, alcohols, organic amines, phenols) are trimethylsiloxylated or trimethylsilylated to make them hydrophobic. It is known to have a sex-making effect.
Therefore, when the conductive particles whose surface is treated with the epoxy group-containing organoalkoxysilane and whose surface is coated with fatty acid are further treated with hexamethyldisilazane, the silanol in the partially hydrolyzed condensate of the epoxy group-containing organoalkoxysilane is obtained. The group can be trimethylsilylated to make it hydrophobic. As a result, the silanol group in the partially hydrolyzed condensate of the epoxy group-containing organoalkoxylane, which covers the conductive particles having the surface coated with fatty acid, becomes a trimethylsiloxy group.
If there is a fatty acid remaining in a free state, the carboxyl group in the fatty acid can be trimethylsilylated to make it hydrophobic. Therefore, the organosilazane treatment can be called a hydrophobic treatment.

The method of further treating the conductive particles whose surface is treated with the epoxy group-containing organoalkoxysilane and whose surface is coated with a fatty acid with organosilazane is a method in which the conductive particles whose surface is coated with a fatty acid are treated with an epoxy group-containing organosilane. It can be carried out according to the method of surface treatment with alkoxysilane.

When the organosilazane is liquid at room temperature, the organosilazane itself can be used as it is, but it is preferable to use a solution obtained by diluting the organosilazane with an organic solvent from the viewpoint of treatment efficiency. The organic solvent therefor is preferably liquid at room temperature, volatile, and free of active hydrogen. Examples include ketones (eg, acetone, methyl ethyl ketone), esters (eg, ethyl acetate), aliphatic hydrocarbon solvents (eg, octane, cyclohexane), aromatic hydrocarbon solvents (eg, toluene, xylene). Alcohols have active hydrogen and react with organosilazanes, which is not preferable.
Moreover, ordinary ethanol contains about 5% by volume of water, and the organosilazane is hydrolyzed, which is not preferable.

Then, the conductive particles having the surface treated with the epoxy group-containing organoalkoxysilane and having the surface coated with the fatty acid are immersed in the organosilazane itself or an organic solvent solution thereof, well stirred, and then allowed to stand to be separated by sedimentation. Then, the target conductive particles are taken out. Alternatively, conductive particles surface-treated with an epoxy group-containing organoalkoxysilane, the surface of which is coated with a fatty acid, and organosilazane itself or an organic solvent solution thereof are well mixed, and then allowed to stand to be separated by sedimentation. The conductive particles are taken out.

A step of immersing the conductive particles whose surface has been coated with a fatty acid with an epoxy group-containing organoalkoxysilane in the organosilazane itself or an organic solvent solution thereof, or which has been surface-treated with an epoxy group-containing organoalkoxysilane The step of mixing the conductive particles whose surface is coated with a fatty acid with the organosilazane itself or an organic solvent solution thereof may be performed at room temperature under an air atmosphere, and is performed by heating to about 40 to 100 ° C. Good. The stirring time and mixing time are preferably 5 minutes to 10 hours.
The conductive particles, which are the target substance and are separated by sedimentation, are preferably dried by air drying, vacuum drying, or the like, and rinsed with a clean organic solvent before drying to remove excess ornosilazane adhering to the surface. May be removed.

The conductive filler produced by the production method of the present invention is a curable silicone composition (for example, addition reaction curable silicone rubber composition, organic peroxide curable silicone rubber composition, room temperature curable silicone rubber composition). ), And is useful as a filler that imparts conductivity to a non-curable silicone composition (for example, silicone oil compound).
In particular, it is useful as a conductive filler to be added to a liquid or paste addition reaction-curable silicone composition, particularly an addition reaction-curable silicone elastomer composition. The blending amount varies depending on its conductivity, specific gravity, desired conductivity, etc., but is usually 30 to 95% by mass, preferably 60 to 90% by mass in the silicone composition.

In the conductive addition reaction-curable silicone composition of the present invention, the base material silicone composition is preferably an addition reaction-curable silicone composition. The addition reaction-curing type is also called a hydrolysis reaction-curing type. In particular, from the viewpoint of workability, an addition reaction-curable silicone composition that is liquid or paste at room temperature is preferable.
Such an addition reaction curable silicone composition comprises (A) a liquid organopolysiloxane having at least two silicon atom-bonded alkenyl groups per molecule, and (B) at least two silicon atom-bonded hydrogen atoms per molecule. The liquid organopolysiloxane and the (C) addition reaction catalyst are included as essential components, and by further containing (D) addition reaction control agent and (E) adhesion-imparting agent, thickening due to addition reaction at room temperature can be achieved. The addition reaction-curable silicone composition can be suppressed to secure a sufficient working time and has excellent adhesiveness to the base material which is in contact with the base material during curing.

The conductive addition reaction-curable silicone composition of the present invention is prepared by mixing the components (A) to (C), (A) to (D), or (A) to (E) with a mixer or the like. It can be easily manufactured. The temperature at the time of mixing is preferably normal temperature, for example, 30 ° C. or less, and a temperature at which no dew condensation occurs so that the addition reaction does not proceed during mixing.

The component (A) is the main component of the conductive addition reaction curable silicone composition of the present invention, and the silicon atom-bonded alkenyl group undergoes an addition reaction with the silicon atom-bonded hydrogen atom in the component (B) to crosslink. Therefore, when the number of silicon atom-bonded alkenyl groups in the component (A) is 2, the number of silicon atom-bonded hydrogen atoms in the component (B) is 3 or more, and the number of silicon atom-bonded hydrogen atoms in the component (B) is 2 or more. When the number is 3, the number of alkenyl groups bonded to silicon atom in the component (A) is preferably 3 or more.
The molecular structure of the component (A) is, for example, linear, partially branched linear, branched, cyclic, or net-like, but rubber or gel having elasticity after curing, that is, elastomer. For this purpose, a straight chain or a straight chain having a partial branch is preferable.

Examples of the alkenyl group include a vinyl group, an allyl group, a butenyl group, a pentenyl group and a hexenyl group, but a vinyl group is common.
The bonding position of the silicon atom-bonded alkenyl group in the component (A) may be at the molecular chain terminal, the molecular chain side chain, or both.

Examples of the silicon atom-bonding group other than the alkenyl group in the component (A) include an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and a heptyl group; a phenyl group, a tolyl group, and a xylyl group. An aryl group such as a naphthyl group; an aralkyl group such as a benzyl group and a phenethyl group; an unsubstituted or substituted monovalent hydrocarbon such as a halogenated alkyl group such as a 3-chloropropyl group and a 3,3,3-trifluoropropyl group Groups are exemplified. Of these, a methyl group is the most common one because it can be easily produced industrially, and then both a methyl group and a phenyl group are common.

The viscosity of the component (A) at 25 ° C. is preferably 10 to 100,000 mPa · s, and more preferably 100 to 10,000 mPa · s, from the viewpoint of handleability of the composition and physical properties after curing. When the viscosity of the component (A) is lower than 10 mPa · s, the mechanical strength of the cured product tends to be insufficient, and when it is higher than 100,000 mPa · s, it is too viscous to be liquid or pasty. This is because it is difficult to obtain the conductive addition reaction-curable silicone composition.

As a typical example of the component (A), dimethylpolysiloxane or dimethylsiloxane / methylvinylsiloxane copolymer with both ends dimethylvinylsiloxy group blocked, dimethylsiloxy / methylvinylsiloxane copolymer with both terminals trimethylsiloxy group blocked, and dimethylvinylsiloxy group at the end There are linear dimethylpolysiloxanes capped with trimethylsiloxy groups, branched methylpolysiloxanes capped with dimethylvinylsiloxy groups and trimethylsiloxy groups, and polysiloxanes in which some of the methyl groups of the above polysiloxanes are replaced with phenyl groups. Two or more kinds of component (A) may be used in combination.

The component (B) is a crosslinking agent for addition reaction of the component (A), and its silicon atom-bonded hydrogen atom undergoes an addition reaction with the silicon atom-bonded alkenyl group in the component (A) to crosslink.
Examples of the molecular structure of the component (B) include linear, partially branched linear, branched, and network structures. The bonding position of the silicon atom-bonded hydrogen atom is at the molecular chain end, the molecular chain side chain, or both. Examples of the group bonded to a silicon atom other than a hydrogen atom in the component (B) include an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group and a heptyl group; a phenyl group, a tolyl group, Examples thereof include xylyl group, naphthyl group and the like; substituted or unsubstituted monovalent hydrocarbon group such as halogenated alkyl group such as 3-chloropropyl group and 3,3,3-trifluoropropyl group. Methyl groups are the most common, followed by both methyl and phenyl groups.

The viscosity of component (B) at 25 ° C. is preferably in the range of 0.1 to 10,000 mPa · s, and more preferably in the range of 1 to 1,000 mPa · s. Typical examples are methylhydrogenpolysiloxanes having both ends trimethylsiloxy groups or both ends dimethylsiloxy groups blocked (that is, methylhydrogenpolysiloxane), dimethylsiloxane methylhydrones having both ends trimethylsiloxy groups or both ends dimethylsiloxy groups blocked. There are siloxane copolymers, cyclic methylhydrogen siloxane oligomers, and tetrakis (dimethylhydrogensiloxy) silane. You may use together 2 or more types of (B) component.

The blending amount of the component (B) may be an amount sufficient to crosslink the component (A) into a rubber-like or gel-like state, and the silicon atom-bonded hydrogen atom and the silicon atom-bonded alkenyl group in the component (A). An example is such that the molar ratio of is 0.3 to 5. When the cured product is gel-like, 0.3 to 0.8 is preferable, and when it is rubber-like, 0.8 to 5 is preferable. Even with the same molar ratio, the weight ratio of the component (A) and the component (B) varies depending on the molecular weight of the component (A) and the content of the silicon atom-bonded alkenyl group and the molecular weight of the component (B) and the content of the silicon atom-bonded hydrogen atom. Therefore, the compounding amount of the component (B) per 100 parts by mass of the component (A) cannot be specified, but it is usually 1 to 30 parts by mass.

The component (C) is a catalyst for promoting the addition reaction between the silicon atom-bonded alkenyl group in the component (A) and the silicon atom-bonded hydrogen atom in the component (B), that is, a catalyst for addition reaction, and platinum. Examples include system catalysts, rhodium catalysts, and palladium catalysts.
Platinum-based catalysts are preferable from the viewpoint of performance and availability, platinum fine powder, platinum-supported silica fine powder, platinum-supported activated carbon, chloroplatinic acid, alcohol modified chloroplatinic acid, platinum diolefin complex, platinum diketone complex. , A dialkenyltetraalkyldisiloxane complex of platinum, and thermoplastic resin fine particles containing these platinum-based catalysts.
The component (C) is blended in a catalytic amount, that is, an amount sufficient to cause a hydrosilation reaction between the silicon atom-bonded alkenyl groups in the component (A) and the silicon atom-bonded hydrogen atoms in the component (B). In the case of a platinum-based catalyst, the platinum atom in this catalyst is generally 0.1 to 100 ppm by mass in the composition. Two or more types of component (C) may be used in combination.

The (D) addition reaction control agent controls the addition reaction rate between the silicon atom-bonded alkenyl group in the component (A) and the silicon atom-bonded hydrogen atom in the component (B) while suppressing curing at room temperature. In order to make it harden rapidly under heating. Alkyne alcohols such as 3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyne-3-ol, phenylbutynol; 3-methyl-3-penten-1-yne, 3,5 -Enein compounds such as dimethyl-3-hexene-1-yne; 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 1,3,5,7-tetramethyl Examples are -1,3,5,7-tetrahexenylcyclotetrasiloxane and benzotriazole. The compounding amount of the component (D) is usually 0.01 to 5 parts by mass with respect to 100 parts by weight of the component (A). By containing the component (D) in addition to the component (A), the component (B), and the component (C), it is possible to make the silicone composition thermosetting with excellent workability that does not easily thicken at room temperature. ..

The (E) adhesion-imparting agent is preferably an organosilane or organosiloxane oligomer having a silicon atom-bonded alkenyl group or at least two alkoxy groups having at least one hydrogen atom bonded to the same silicon atom. Examples of the molecular structure of the organosiloxane oligomer include linear, linear with some branches, branched, and cyclic. Examples of the silicon atom-bonded alkenyl group in this component include a vinyl group, an allyl group, a butenyl group, a pentenyl group and a hexenyl group, and a vinyl group is particularly preferable. Examples of the silicon atom-bonded alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a methoxyethoxy group, and a methoxy group bonded to the same silicon atom is preferable. Examples of silicon atom-bonding groups other than alkenyl groups and alkoxy groups include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group and heptyl group; phenyl group, tolyl group, xylyl group, naphthyl group. Aryl groups such as; aralkyl groups such as benzyl and phenethyl groups; halogenated alkyl groups such as 3-chloropropyl group, 3,3,3-trifluoropropyl group; 3-glycidoxypropyl group, 4-glycid Glycidoxyalkyl group such as oxybutyl group; (3,4-epoxycyclohexyl) alkyl group such as 2- (3,4-epoxycyclohexyl) ethyl group and 3- (3,4-epoxycyclohexyl) propyl group; 4 Examples thereof include oxiranylalkyl groups such as -oxiranylbutyl group and 8-oxiranyloctyl group. It is preferable to have at least one epoxy group-containing monovalent organic group in one molecule, since good adhesiveness can be imparted to various base materials that are in contact with the composition during curing.

Examples of the adhesion-imparting agent include vinyltrimethoxysilane, allyltrimethoxysilane, hydroentrymethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3 -A partial condensate of glycidoxypropyltrimethoxysilane and a dimethylsiloxane oligomer capped with silanol groups at both ends, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, and a dimethylsiloxane oligomer capped with silanol groups at both ends There is a partial condensate of.
The adhesiveness-imparting agent is preferably liquid at room temperature and has a viscosity at 25 ° C. of 1 to 500 mPa · s. The blending amount is usually 0.1 to 5 parts by mass with respect to 100 parts by mass of the component (A).

From the viewpoint of workability during use, the conductive addition reaction-curable silicone composition is preferably paste at room temperature and thermosetting. The cured product is preferably rubber-like or gel-like (so-called semi-cured, partially cross-linked). The conductive addition reaction curable silicone composition of the present invention may simultaneously have thermal conductivity.

The amount of the conductive filler compounded in the conductive addition reaction curable silicone composition of the present invention varies depending on its conductivity, specific gravity, target conductivity, etc., but is usually 30 to 95% by mass in the composition. And preferably 60 to 90% by mass. A conductive addition reaction-curable silicone composition can be easily produced by uniformly mixing the addition reaction-type silicone composition and the conductive filler with a mixer or the like. The temperature at the time of mixing is preferably room temperature, for example, 30 ° C. or lower, and a temperature at which no dew condensation occurs so that the addition reaction of the addition reaction type silicone composition does not proceed during mixing.

The conductive addition reaction-curable silicone composition of the present invention contains a reinforcing filler (for example, fumed silica), a bulking filler (for example, quartz powder), a solvent, a coloring agent, a difficult additive, unless the purpose of the present invention is impaired. You may mix additives, such as a flame retardant and non-reactive silicone oil.

INDUSTRIAL APPLICABILITY The conductive addition reaction curable silicone composition of the present invention is useful as an adhesive for electric / electronic parts, a sealant, a potting agent, a protective coating, etc., and also as an adhesive between a semiconductor element and a heat sink. It is useful. The addition reaction curable silicone composition comprising the above components (A) to (C) cures at room temperature, but the addition reaction curable silicone composition comprising the components (A) to (D) is at room temperature. Is hard to thicken, and hardens rapidly when heated. The heating temperature is preferably within the range of 50 to 250 ° C, more preferably within the range of 100 to 200 ° C.

In the semiconductor device of the present invention, the semiconductor element is covered with the cured product of the conductive addition reaction-curable silicone elastomer composition of the present invention. A part of the semiconductor element may be covered, or the whole semiconductor element may be covered. The semiconductor element may be adhered to another member (for example, a heat sink) via the cured product of the conductive addition reaction-curable silicone elastomer composition. Examples of the semiconductor element include a diode, a transistor, a thyristor, a monolithic IC, or a semiconductor element in a hybrid IC. Examples of semiconductor devices include diodes, transistors, thyristors, monolithic ICs, hybrid ICs, LSIs, VLSIs, and IGBTs.

FIG. 1 is a sectional view of an LSI which is an example of the semiconductor device of the present invention. In the LSI of FIG. 1, a semiconductor element 4 is mounted on a circuit board 1, and the semiconductor element 4 and a wiring 2 connected to an external lead are electrically connected by a gold electrode (bump) 3. .. The heat sink 6 is placed on the back surface of the semiconductor element 4, and the conductive silicone rubber 5 which is a cured product of the conductive addition reaction curable silicone rubber composition is present between the semiconductor element 4 and the heat sink 6. The conductive silicone rubber 5 is well adhered to both the semiconductor element 1 and the heat sink 6. Since the conductive silicone rubber 5 also has thermal conductivity, the heat generated by the semiconductor element 4 can be efficiently dissipated through the heat dissipation plate 6.

Examples of the material of the circuit board 1 include organic resins such as polyimide resin, bismaleimide triazine resin, glass fiber reinforced epoxy resin, bakelite resin, and phenol resin; ceramics; metals such as copper and aluminum. Examples of the material of the wiring 2 include gold, copper, and silver-palladium. As a material other than gold for the gold electrodes (bumps) 3, a gold alloy is exemplified. Examples of the material of the heat dissipation plate 6 include metals having good conductivity such as aluminum, copper, nickel and the like. In addition to the semiconductor element 4, electronic components such as resistors, capacitors and coils may be mounted on the circuit board 1.

In order to manufacture the semiconductor device of the present invention, for example, the semiconductor element 4 is mounted on the circuit board 1 and then the semiconductor element 4 and the wiring 2 printed on the circuit board 1 are made of gold electrodes ( After electrically connecting with the bumps 3, the conductive addition reaction curable silicone rubber composition 5 of the present invention is applied to the back surface of the semiconductor element 4, and the heat dissipation plate 6 is placed thereon, and the temperature is 100 to 200 ° C. Heat to cure.

The conductive filler, the conductive addition reaction curable silicone rubber composition and the semiconductor device manufactured by the manufacturing method of the present invention will be described in detail with reference to Examples. The viscosity in the examples is a value measured at 25 ° C. Further, the storage stability of the conductive addition reaction-curable silicone rubber composition, the volume resistivity of the cured product of the conductive addition-reaction-curable silicone rubber composition, and the hardness of the cured product of the conductive addition-reaction-curable silicone rubber composition. The thermal stability and the reliability of the semiconductor device were measured as follows.

[Storage stability of conductive addition reaction curable silicone rubber composition]
The paste-like conductive addition reaction-curable silicone rubber composition was placed in a 100 ml glass bottle, the temperature was adjusted at 25 ° C. for 30 minutes, and the value measured by a rotary viscometer using a spindle was taken as the initial viscosity. The number of rotations at that time was appropriately selected depending on the viscosity of the paste-like conductive addition reaction-curable silicone rubber composition. After this measurement, the glass bottle was closed with a lid and stored in an atmosphere of 25 ° C. for 100 hours, and then the viscosity was measured in the same manner. The smaller the difference between the initial viscosity and the viscosity after 100 hours of storage, the better the storage stability.

[Volume resistivity of cured product of conductive addition reaction curable silicone rubber composition]
The paste-like conductive addition reaction curable silicone rubber composition is poured into a mold having a length and width of 5 cm × 5 cm and a depth of 2 mm, and heated in a hot-air circulation type oven at 150 ° C. for 1 hour to be cured, and JIS K 7194 is used. The volume resistivity (unit: Ω · cm) was measured by the method according to (1).

[Thermal Stability of Hardness of Cured Product of Conductive Addition Reaction-Curable Silicone Rubber Composition]
The paste-like conductive addition reaction-curable silicone rubber composition was poured into the mold, and the conductive silicone rubber sheets obtained by heating for 1 hour in a hot-air circulation type oven at 150 ° C. for one hour were stacked to obtain a thickness. The hardness of 6 mm was measured using a hardness tester (type A durometer) according to JIS K6253. Next, this rubber sheet was heated and aged for 24 hours in a hot air circulation type oven at 150 ° C. in the atmosphere, and then the hardness was measured using a hardness tester (type A durometer) according to JIS K6253. The smaller the difference between the initial hardness and the hardness after aging, the better the thermal stability.

[Reliability of semiconductor devices]
The semiconductor device shown in FIG. 1 was created. That is, after mounting the semiconductor element 4 on the circuit board 1 made of glass fiber reinforced epoxy resin having the wiring 2 formed by printing on the surface and the external leads at the ends, the semiconductor element 4 and the wiring 2 are made of gold. The electrodes (bumps) 3 were electrically connected. A paste-like conductive addition reaction-curable silicone rubber composition is applied on the back surface of the semiconductor element 4 by a dispenser, and then a heat sink 6 made of aluminum is attached and immediately in a hot air circulation oven at 150 ° C. in the atmosphere. By heating, 10 semiconductor devices were produced in which the semiconductor element 4 and the heat sink 6 were adhered by the cured product 5 of the conductive addition reaction curing type silicone rubber composition.
The semiconductor device thus produced was subjected to 100 cycles of a thermal cycle test in which one cycle consisted of −40 ° C. for 30 minutes and + 150 ° C. for 30 minutes, and then conductivity was added between the semiconductor element 4 and the heat sink 6. Regarding the cured product 5 of the reaction-curable silicone rubber composition, the presence or absence of peeling between the semiconductor element 4 and the heat dissipation plate 6 is observed with a microscope, and the peeled one is regarded as defective and the defect rate (%) Was calculated.

[Reference Example 1]
In a mixer, a solution of 1.0 g of 3-glycidoxypropyltrimethoxysilane in 300 g of ethanol (for research and experiment) (manufactured by Kanto Chemical Co., Inc., water content 0.1 v / v%) was added to a solution of olein on the surface. 100 g of spherical silver particles A (content of oleic acid: 0.3% by mass) coated with an acid and having an average particle size of 1 μm were added, and the mixture was stirred at 70 ° C. for 3 hours. After the stirring, the spherical silver particles were allowed to settle at room temperature for 10 minutes, the supernatant liquid was extracted, and 300 g of ethanol was added to the residue and stirred for 15 minutes. After stirring, the spherical silver particles A were allowed to settle for 10 minutes, the supernatant liquid was extracted, and the residual spherical silver particles A were air-dried at room temperature for 24 hours to coat the surface with oleic acid. A spherical silver particle A having an average particle diameter of 1 μm, which was surface-treated with 3-glycidoxypropyltrimethoxysilane, was prepared.

The supernatant was poured onto a flat glass plate, spread, and air-dried to form a transparent, gel-like film. When water was dropped onto this gel-like film, it did not repel water and got wet.
Since the starting material, 3-glycidoxypropyltrimethoxysilane, is a free-flowing transparent liquid, it can be said that this gel-like coating is composed of a partial hydrolysis-condensation product of 3-glycidoxypropyltrimethoxysilane. it can. Therefore, in the spherical silver particles B, the spherical silver particles A whose surface is coated with oleic acid and have an average particle size of 1 μm are coated with a partially hydrolyzed condensate film of 3-glycidoxypropyltrimethoxysilane. It can be said that

[Reference Example 2]
In Reference Example 1, except that 3-glycidoxypropyltrimethoxysilane was used in place of 3-glycidoxypropyltrimethoxysilane, the same procedure was followed except that the surface was coated with oleic acid and the average particle size was 1 μm. A spherical silver particle A, which was a spherical silver particle C surface-treated with 3-glycidoxypropyltriethoxysilane, was prepared.

In a mixer, a solution of 100 g of hexamethyldisilazane dissolved in 50 g of toluene (Kanto Chemical Co., Inc., first grade reagent) was spherical treated with the surface of 3-glycidoxypropyltrimethoxysilane prepared in Reference Example 1. 100 g of silver particles B was added, and the mixture was stirred at 100 ° C. for 4 hours. After stirring, the spherical silver particles B were allowed to settle at room temperature for 30 minutes, the supernatant was extracted, 50 g of hexane was added to the residue, and the mixture was stirred for 2 hours. After stirring, the spherical silver particles B were allowed to settle by standing for 30 minutes, the supernatant liquid was extracted, and the residual spherical silver particles B were dried at 50 ° C. and a vacuum degree of 1333 Pa for 5 hours, and the surface was treated with oleic acid. Conductive spherical silver particles D (conductive filler) obtained by subjecting the coated spherical silver particles A having an average particle diameter of 1 μm to a surface treatment with 3-glycidoxypropyltrimethoxysilane and further with hexamethyldisilazane. ) Was prepared.

The glass plate to which the gel-like coating of [Reference Example 1] is attached is put into a solution prepared by dissolving 100 g of hexamethyldisilazane in 50 g of toluene (manufactured by Kanto Chemical Co., Inc., first-grade reagent), and then at 100 ° C. for 4 hours. It was stirred. After stirring, the glass plate to which the gel film was attached was taken out and air-dried. When water was dropped on the gel film, the water was repelled. It was found that the gel film became hydrophobic. It can be said that the silanol group in the partially hydrolyzed condensate of 3-glycidoxypropyltrimethoxysilane is a trimethylsiloxy group.
In the conductive spherical silver particles D, the spherical silver particles A having an average particle size of 1 μm, the surfaces of which are coated with oleic acid, are coated with a partially hydrolyzed condensate film of 3-glycidoxypropyltrimethoxysilane. It can be said that the silanol group in the partially hydrolyzed condensate is a trimethylsiloxy group.

In Example 1, instead of the spherical silver particles B treated with 3-glycidoxypropyltrimethoxysilane prepared in Reference Example 1, surface treatment was performed with 3-glycidoxypropyltriethoxysilane prepared in Reference Example 2. The spherical silver particles A whose surface was coated with oleic acid and which had an average particle diameter of 1 μm were surface-treated with 3-glycidoxypropyltriethoxysilane in the same manner as described above except that the spherical silver particles C were used. Conductive spherical silver particles E (conductive filler) prepared by treatment with hexamethyldisilazane were prepared.

で示される液状オルガノポリシロキサン１．３質量部を均一に混合して、粘度が３．９Ｐａ・ｓである、液状の付加反応硬化型シリコーンゴム組成物を調製した。
ついで、実施例１で調製した導電性球状銀粒子Ｄ９２質量部を加えて均一に混合して、粘度が１７２Ｐａ・ｓである、ペースト状の導電性付加反応硬化型シリコーンゴム組成物を調製した。In the mixer, as a main component, (A) viscosity of 5000 mPa · s, molecular chain both ends dimethylvinylsiloxy group-blocked linear dimethylpolysiloxane (content of vinyl group bonded to silicon atom = 0.13 mass) %) 130 parts by mass, (B) as a cross-linking agent for addition reaction, a dimethylsiloxy-methylhydrogen siloxane copolymer (B) having a viscosity of 5 mPa · s, capped with trimethylsiloxy groups at both ends of the molecular chain (of a hydrogen group bonded to a silicon atom). Content = 0.73% by mass) 3.4 parts by mass, (C) platinum 1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex (present composition) as a catalyst for addition reaction In, the amount of platinum metal is 5 ppm by mass unit), (D) 3-phenyl-1-butyn-3-ol (the amount of which is 1100 ppm by mass unit in the composition) as an addition reaction control agent, and , (E) average unit formula as an adhesiveness-imparting agent:

1.3 parts by mass of the liquid organopolysiloxane represented by the formula (4) was uniformly mixed to prepare a liquid addition reaction curable silicone rubber composition having a viscosity of 3.9 Pa · s.
Then, 92 parts by mass of the conductive spherical silver particles D prepared in Example 1 were added and uniformly mixed to prepare a paste-like conductive addition reaction curable silicone rubber composition having a viscosity of 172 Pa · s.

The storage stability of the conductive addition reaction curable silicone rubber composition, the volume resistivity of the cured product, the thermal stability of the hardness of the cured product, and the semiconductor element and the heat sink are the conductive addition reaction curable type. The results of measuring the reliability of the semiconductor device adhered by the cured product of the silicone rubber composition are summarized in Table 1. It was found that this conductive addition reaction-curable silicone rubber composition has excellent storage stability, and that the cured product has excellent conductivity and thermal stability, as well as excellent reliability of the semiconductor device.

In Example 3, except that the conductive spherical silver particles D prepared in Example 1 were replaced by the conductive spherical silver particles E prepared in Example 2, the viscosity was 166 Pa · s. A paste-like conductive addition reaction curable silicone rubber composition of s was prepared.

The storage stability of the conductive addition reaction curable silicone rubber composition, the volume resistivity of the cured product, the thermal stability of the hardness of the cured product, and the semiconductor element and the heat dissipation plate are the conductive silicone rubber composition. The results of measuring the reliability of the semiconductor device bonded by the cured product of Table 1 are summarized in Table 1. It was found that this conductive addition reaction-curable silicone rubber composition has excellent storage stability, and that the cured product has excellent conductivity and thermal stability, as well as excellent reliability of the semiconductor device.

In Example 3, as the component (B), a dimethylsiloxy / methylhydrogen siloxane copolymer having a viscosity of 5 mPa · s and having trimethylsiloxy groups blocked at both molecular chain terminals (content of hydrogen groups bonded to silicon atom = 0. 73 mass%), a dimethylsiloxane / methylhydrogensiloxane copolymer having a viscosity of 5 mPa · s and having trimethylsiloxy groups at both molecular chain ends (content of hydrogen groups bonded to silicon atoms = 0.73% by mass) 1.7 parts by mass and 2.8 parts by mass of dimethyl siloxane having a viscosity of 5 mPa · s and having both ends of the molecular chain blocked with dimethyl hydrogen group (content of hydrogen groups bonded to silicon atoms = 0.28% by mass) In the same manner as in Example 3, a paste-like conductive addition reaction curable silicone rubber composition having a viscosity of 189 Pa · s was prepared.

The storage stability of the conductive addition reaction curable silicone rubber composition, the volume resistivity of the cured product, the thermal stability of the hardness of the cured product, and the semiconductor element and the heat dissipation plate are The results of measuring the reliability of the semiconductor device bonded with the cured product of the silicone rubber composition are summarized in Table 1. It was found that this conductive addition reaction-curable silicone rubber composition has excellent storage stability, the cured product has excellent conductivity and thermal stability, and the semiconductor device has excellent reliability.

[Comparative Example 1]
In Example 3, instead of the spherical silver particles D prepared in Example 1, spherical silver particles having an average particle size of 1 μm, the surface of which was coated with oleic acid (content of oleic acid: 0.3% by mass). ) A paste-like conductive addition reaction curable silicone rubber composition having a viscosity of 158 Pa · s was prepared in the same manner as in Example 3 except that A was used.

The storage stability of the conductive addition reaction curable silicone rubber composition, the volume resistivity of the cured product, the thermal stability of the hardness of the cured product, and the semiconductor element and the heat sink are the conductive addition reaction curable type. The results of measuring the reliability of the semiconductor device adhered by the cured product of the silicone rubber composition are summarized in Table 2. It was found that this conductive addition reaction-curable silicone rubber composition had poor storage stability, the cured product had poor conductivity and thermal stability, and the semiconductor device had low reliability.

[Comparative example 2]
In Example 3, except that the conductive spherical silver particles D prepared in Example 1 were replaced by spherical silver particles B surface-treated with 3-glycidoxypropyltrimethoxysilane prepared in Reference Example 1. In the same manner as in Example 3, a paste-like conductive addition reaction curable silicone rubber composition having a viscosity of 162 Pa · s was prepared.

The storage stability of the conductive addition reaction curable silicone rubber composition, the volume resistivity of the cured product, the thermal stability of the hardness of the cured product, and the semiconductor element and the heat sink are the conductive addition reaction curable type. The results of measuring the reliability of the semiconductor device adhered by the cured product of the silicone rubber composition are summarized in Table 2. It was found that although the conductive addition reaction-curable silicone rubber composition had relatively stable conductivity and thermal stability of the cured product, it had poor storage stability.

[Comparative Example 3]
In Example 3, except that the conductive spherical silver particles D prepared in Example 1 were replaced by spherical silver particles C surface-treated with 3-glycidoxypropyltriethoxysilane prepared in Reference Example 2 In the same manner as in Example 3, a paste-like conductive addition reaction curable silicone rubber composition having a viscosity of 170 Pa · s was prepared.

The storage stability of the conductive addition reaction curable silicone rubber composition, the volume resistivity of the cured product, the thermal stability of the hardness of the cured product, and the semiconductor element and the heat sink are the conductive addition reaction curable type. The results of measuring the reliability of the semiconductor device adhered by the cured product of the silicone rubber composition are summarized in Table 2. It was found that although the conductive addition reaction-curable silicone rubber composition had relatively stable conductivity and thermal stability of the cured product, it had poor storage stability.

[Comparative Example 4]
In the same manner as in Reference Example 1, except that methyltrimethoxylane was used instead of 3-glycidoxypropyltrimethoxysilane, spherical silver particles having an average particle size of 1 μm whose surface was coated with oleic acid were used. Therefore, spherical silver particles F surface-treated with methyltrimethoxysilane were prepared.

[Comparative Example 5]
In Example 3, except that the conductive spherical silver particles D prepared in Example 1 were replaced by the spherical silver particles F surface-treated with methyltrimethoxysilane prepared in Comparative Example 4, Similarly, a paste-like conductive addition reaction curable silicone rubber composition having a viscosity of 155 Pa · s was prepared.

The storage stability of the conductive addition reaction curable silicone rubber composition, the volume resistivity of the cured product, the thermal stability of the hardness of the cured product, and the semiconductor element and the heat sink are the conductive addition reaction curable type. The results of measuring the reliability of the semiconductor device adhered by the cured product of the silicone rubber composition are summarized in Table 3. It was found that this conductive addition reaction-curable silicone rubber composition had poor storage stability, and the cured product had relatively poor conductivity and thermal stability. The necessity of the epoxy group was confirmed.

1 Circuit wiring board 2 Wiring 3 Gold electrode (bump)
4 Semiconductor elements (which are dummy elements)
5 Cured product of conductive addition reaction curing type silicone rubber composition 6 Aluminum heat sink (cooling fin)

Industrial applications

INDUSTRIAL APPLICABILITY The method for producing a conductive filler of the present invention is useful for producing a conductive filler capable of imparting excellent conductivity and storage stability to a non-curable silicone composition and a curable silicone composition. is there.
A conductive addition reaction-curable silicone composition containing a conductive filler produced by the production method of the present invention is useful as an adhesive for electric / electronic parts, a sealant, a potting agent, a protective coating agent, etc. Therefore, it is also useful as an adhesive between the semiconductor element and the heat sink.
The semiconductor device of the present invention is useful as a diode, a transistor, a thyristor, a monolithic IC, a hybrid IC, an LSI, a VLSI, an IGBT and the like.

Claims (11)

A method for producing a conductive filler, characterized in that conductive particles having a surface coated with a fatty acid are surface-treated with an epoxy group-containing organoalkoxysilane, and further treated with an organosilazane. The surface treatment of the conductive particles whose surface is coated with a fatty acid with an epoxy group-containing organoalkoxysilane, the surface is mixed with a conductive particle coated with a fatty acid and the epoxy group-containing organoalkoxysilane itself or an organic solvent solution thereof, The method for producing a conductive filler according to claim 1, wherein the surface-treated conductive particles are separated from the mixture. The conductive particles are conductive metal particles, the epoxy group-containing organoalkoxysilane is glycidoxyalkyltrialkoxysilane or 2- (3,4-epoxycyclohexyl) alkyltrialkoxysilane, and the organosilazane is hexaorganodisilazane. The method for producing a conductive filler according to claim 1 or 2, wherein The conductive metal particles are silver particles, the glycidoxyalkyltrialkoxysilane is 3-glycidoxypropyltrimethoxysilane or 3-glycidoxypropyltriethoxysilane, and the hexaorganodisilazane is hexamethyldisilazane. It exists, The manufacturing method of the electroconductive filler of Claim 3 characterized by the above-mentioned. Conductive addition reaction curing type, characterized in that conductive particles whose surface is coated with a fatty acid are surface-treated with an epoxy group-containing organoalkoxysilane, and further containing conductive particles treated with an organosilazane. Silicone composition. The conductive particles are conductive metal particles, the epoxy group-containing organoalkoxysilane is glycidoxyalkyltrialkoxysilane or 2- (3,4-epoxycyclohexyl) alkyltrialkoxysilane, and the organosilazane is hexaorganodisilazane. The conductive addition reaction-curable silicone composition according to claim 5, wherein The conductive metal particles are silver particles, the glycidoxyalkyltrialkoxysilane is 3-glycidoxypropyltrimethoxysilane or 3-glycidoxypropyltriethoxysilane, and the hexaorganodisilazane is hexamethyldisilazane. The conductive addition reaction-curable silicone composition according to claim 6, which is characterized by being present. The addition reaction-curable silicone composition constituting the conductive addition reaction-curable silicone composition has (A) a liquid organopolysiloxane having at least two silicon atom-bonded alkenyl groups in one molecule, and (B) a silicon atom-bonded hydrogen. The electroconductive addition according to any one of claims 5 to 7, which comprises a liquid organopolysiloxane having at least two atoms in one molecule and (C) a catalyst for addition reaction. Reaction-curable silicone composition. The conductive addition reaction curable silicone composition according to claim 8, further comprising (D) an addition reaction control agent and (E) an adhesiveness-imparting agent. Curing of a conductive addition reaction-curable silicone elastomer composition in which conductive particles having a surface coated with a fatty acid are surface-treated with an epoxy group-containing organoalkoxysilane and further containing conductive particles treated with an organosilazane A semiconductor device, wherein a semiconductor element is covered with an object. 11. The semiconductor device according to claim 10, wherein the semiconductor element is adhered to the heat sink through the cured product of the conductive addition reaction-curable silicone elastomer composition according to claim 10.

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