WO2020137332A1 - Heat-conductive silicone composition and semiconductor device - Google Patents

Abstract

Provided is a heat-conductive silicone composition that provides excellent heat dissipation effects, effectively suppresses in-system air bubbles, and yields a cured product having excellent external appearance and physical properties.　This heat-conductive silicone composition contains the following components (A), (B), (C), (D), and (E). (A) An organopolysiloxane containing, within the molecule, at least two alkenyl groups bonded to a silicon atom (B) An organohydrodiene polysiloxane containing, within the molecule, at least two hydrogen atoms bonded to a silicon atom (SiH group) (C) A hydrosilylation reaction catalyst (D) Silver powder having a tapped density of 3.0 g/cm3 or more, a specific surface area of 2.0 m2/g or less, and an aspect ratio of 1-30 (E) Palladium powder having an average grain diameter of 1-100 nm, or crystalline silica, amorphous silica, or carbon on which the palladium powder is carried

Description

Thermally conductive silicone composition and semiconductor device

The present invention relates to a silicone composition having excellent thermal conductivity and a semiconductor device.

Since many electronic components generate heat during use, it is necessary to remove heat from the electronic components in order for them to function properly. Particularly in integrated circuit elements such as CPUs used in personal computers, the amount of heat generation is increasing due to the increase in operating frequency, and heat countermeasures have become an important issue.
Therefore, many methods of radiating this heat have been proposed. Particularly for electronic components that generate a large amount of heat, a method has been proposed in which a thermally conductive grease or a thermally conductive material such as a thermally conductive sheet is interposed between the electronic components and a member such as a heat sink to release heat.

Japanese Unexamined Patent Publication (Kokai) No. 2-153995 (Patent Document 1) discloses a silicone grease composition in which a specific organopolysiloxane is mixed with spherical hexagonal aluminum nitride powder having a certain particle size range. Japanese Patent Application Laid-Open No. 10-110179 (Patent Document 3) discloses a thermally conductive organosiloxane composition in which an aluminum nitride powder having a small particle size and an aluminum nitride powder having a coarse particle size are combined. A heat conductive silicone grease in which aluminum powder and zinc oxide powder are combined is disclosed in Japanese Patent Laid-Open No. 2000-63872 (Patent Document 4), which is a heat conductive grease composition using aluminum nitride powder surface-treated with organosilane. It is disclosed.
Aluminum nitride has a thermal conductivity of 70 to 270 W/mK, and a material having a higher thermal conductivity than this is diamond having a thermal conductivity of 900 to 2,000 W/mK. Japanese Unexamined Patent Publication No. 2002-30217 (Patent Document 5) discloses a heat conductive silicone composition using diamond, zinc oxide and a dispersant in a silicone resin.
Further, in JP-A-2000-63873 (Patent Document 6) and JP-A-2008-222776 (Patent Document 7), there is disclosed a heat conductive grease composition obtained by mixing metal aluminum powder with a base oil such as silicone oil. It is disclosed.
Furthermore, Japanese Patent No. 3130193 (Patent Document 8), Japanese Patent No. 3677671 (Patent Document 9) and the like, which use silver powder having high thermal conductivity as a filler, are also disclosed.
However, any of the heat conductive materials and heat conductive greases have recently become insufficient in heat radiation effect with respect to the heat generation amount of integrated circuit elements such as CPUs.

Further, a thermally conductive silicone composition obtained by blending a thermally conductive filler in an organopolysiloxane containing an alkenyl group bonded to a silicon atom and an organohydrogensiloxane containing a hydrogen atom bonded to a silicon atom is a platinum-based compound. It is known that an elastic cured product exhibits excellent reliability by being subjected to an addition reaction in the presence of a catalyst to give an elastic cured product (Patent Document 10).

JP-A-2-153995 JP-A-3-14873 Japanese Patent Laid-Open No. 10-110179 JP-A-2000-63872 JP-A-2002-30217 Japanese Patent Laid-Open No. 2000-63873 JP, 2008-222776, A Japanese Patent No. 3130193 Japanese Patent No. 3677671 JP, 2017-066406, A

The composition described in Patent Document 10 or the like is a catalyst that promotes hydrosilylation represented by water present in the system, an organohydrogenpolysiloxane containing a hydrogen atom (SiH group) bonded to a silicon atom, and a platinum catalyst. With the coexistence of hydrogen, the hydrogen of the SiH group is desorbed, whereby bubbles of hydrogen gas are generated in the system, which may impair the appearance and physical properties of the cured product. Further, when the basic component is brought into contact with the basic component or the basic component coexists in the same system, hydrogen in the SiH group is desorbed, and bubbles of hydrogen gas are generated in the system to improve the appearance and physical properties of the cured product. In some cases, it may be damaged.
As means for reducing hydrogen gas generated in the system, use of an organohydrogenpolysiloxane containing SiH groups having a low SiH group content or a structure with low activity as the organohydrogenpolysiloxane containing SiH groups, Examples include reducing the amount of addition of the SiH group-containing organohydrogenpolysiloxane, but since the structure and amount of the component acting as a crosslinking agent are limited, the properties of the composition are limited and desired. There is a problem that physical properties and heat dissipation effect cannot be obtained.
Therefore, an object of the present invention is to provide a heat conductive silicone composition that exhibits a good heat dissipation effect, effectively suppresses bubbles in the system, and gives a cured product having good appearance and physical properties. ..

The present inventors have conducted extensive studies in order to achieve the above objects, and a specific tap density, a specific surface area, and a silver powder having an aspect ratio, and a fine powder of palladium powder or silica carrying the same, etc. It was found that the thermal conductivity of the composition is remarkably improved by mixing the compound with a specific organopolysiloxane, and the present invention has been completed.
That is, the present invention provides the following thermally conductive silicone composition and the like.

<1>
A thermally conductive silicone composition containing the following components (A), (B), (C), (D) and (E).
(A) Organopolysiloxane containing at least two alkenyl groups bonded to silicon atoms in one molecule: 100 parts by mass (B) At least two hydrogen atoms (SiH groups) bonded to silicon atoms in one molecule Organohydrogenpolysiloxane: An amount (C) hydrosilylation reaction in which the amount of hydrogen atoms bonded to silicon atoms in the component (B) is 0.2 to 10 mol, based on 1 mol of alkenyl groups in the entire composition. Catalyst: Effective amount (D) Silver powder having a tap density of 3.0 g/cm ³ or more, a specific surface area of 2.0 m ² /g or less, and an aspect ratio of 1 to 30: (A) 300 to 11,000 parts by mass (E) Palladium powder having an average particle diameter of 1 nm to 100 nm, or crystalline silica, amorphous silica or carbon:(A ) Amount of palladium powder in an amount of 0.00001 to 0.05 parts by mass relative to 100 parts by mass of component <2>
A semiconductor device comprising a heat-generating electronic component and a heat radiator, wherein the heat-conductive silicone composition according to <1> is interposed between the heat-generating electronic component and the heat radiator. apparatus.
<3>
<1> A semiconductor device having a step of heating the thermally conductive silicone composition according to <1> to 80° C. or higher under a pressure of 0.01 MPa or higher between a heat-generating electronic component and a radiator. Production method.

The thermally conductive silicone composition of the present invention has a structure and a compounding amount that exert desired properties without limitation of the structure and the compounding amount of the SiH group-containing organohydrogenpolysiloxane which is one component of the composition. Since the cured product has excellent thermal conductivity and can suppress bubbles in the system, the appearance and physical properties of the cured product are not impaired, and it is useful for semiconductor devices.

It is a longitudinal cross-sectional schematic diagram which shows an example of the semiconductor device of this invention.

The heat conductive silicone composition of the present invention will be described in detail below.

Component (A) The organopolysiloxane of component (A) is the base polymer of the composition of the present invention and contains at least two alkenyl groups bonded to silicon atoms in one molecule.
Examples of the molecular structure of the component (A) include a linear structure and a cyclic structure. These structures may have a branch, but the main chain is basically composed of repeating diorganosiloxane units. Therefore, a linear diorganopolysiloxane in which both ends of the molecular chain are blocked with a triorganosiloxy group is preferably used as the component (A).
If the component (A) has a kinematic viscosity at 25° C. of less than 10 mm ² /s, oil bleeding tends to occur when it is made into a composition, and if it is more than 100,000 mm ² /s, the composition when blended into the composition is Since the absolute viscosity is high, the handling property is low. Therefore, the kinematic viscosity of the component (A) at 25° C. is preferably 10 to 100,000 mm ² /s, and particularly preferably 100 to 50,000 mm ² /s. The kinematic viscosity of the organopolysiloxane of component (A) described in the present specification is a value at 25° C. measured with an Ostwald viscometer.

As the alkenyl group bonded to the silicon atom in the component (A), for example, a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group and the like, preferably having 2 to 8 carbon atoms, more preferably 2 to 4 are mentioned, and a vinyl group is particularly preferable. When the organopolysiloxane of the component (A) has a linear structure, the alkenyl group may be bonded to a silicon atom only at one of the molecular chain terminal and the part not at the molecular chain terminal, or the silicon may be bonded at both of them. It may be bonded to an atom.

Examples of the organic group bonded to a silicon atom other than the alkenyl group in the component (A) include an alkyl group, particularly a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a cyclohexyl group, a heptyl group. An alkyl group having 1 to 10 carbon atoms such as; an aryl group, particularly an aryl group having 6 to 14 carbon atoms such as a phenyl group, a tolyl group, a xylyl group, a naphthyl group; an aralkyl group, particularly a benzyl group, a phenethyl group Aralkyl groups having 7 to 14 carbon atoms such as; halogenated alkyl groups, particularly halogenated alkyl groups having 1 to 3 carbon atoms such as chloromethyl group, 3-chloropropyl group, 3,3,3-trifluoropropyl group Examples thereof include an unsubstituted or halogen-substituted monovalent hydrocarbon group such as an alkyl group, and a methyl group and a phenyl group are particularly preferable.

Specific examples of the component (A) include a dimethylsiloxy group-capped dimethylsiloxysiloxane block-capped with trimethylsiloxy groups at both molecular chain ends, a trimethylsiloxy group-blocked methylvinylpolysiloxane blocked with trimethylsiloxy groups at both molecular chain ends, and a dimethylsiloxy group-capped dimethyl block at both molecular chain ends. Siloxane/Methylvinylsiloxane/Methylphenylsiloxane Copolymer, Dimethylvinylsiloxy group-blocked dimethylpolysiloxane at both molecular chain ends, Dimethylvinylsiloxy group-blocked methylvinylpolysiloxane at both molecular chain ends, Dimethylvinylsiloxy group-blocked dimethyl chain at both molecular chain ends Siloxane/methylvinylsiloxane copolymer, dimethylvinylsiloxy group-blocked dimethylsiloxane at both molecular chain ends, dimethylpolysiloxane, methylvinylsiloxane/methylphenylsiloxane copolymer, trivinylsiloxy group-blocked dimethylpolysiloxane at both molecular chain ends, formula: R ¹ ₃ SiO _0.5 (R ¹ is an unsubstituted or substituted monovalent hydrocarbon group other than an alkenyl group. The same applies hereinafter) and a formula: R ¹ ₂ R ² SiO _0.5 (R ² is an alkenyl group. The same shall apply hereinafter) and an organopolysiloxane copolymer comprising a unit represented by the formula: R ¹ ₂ SiO and a siloxane unit represented by the formula: SiO ₂ , represented by the formula: R ¹ ₃ SiO _0.5 Organopolysiloxane copolymer comprising a siloxane unit represented by the formula: R ¹ ₂ R ² SiO _0.5 and a siloxane unit represented by the formula: SiO ₂ , represented by the formula: R ¹ ₂ R ² SiO _0.5 An organopolysiloxane copolymer composed of a siloxane unit and a siloxane unit represented by the formula: R ¹ ₂ SiO and a siloxane unit represented by the formula: SiO ₂ , a siloxane unit represented by the formula: R ¹ R ² SiO and a formula: R ^An organopolysiloxane copolymer composed of a siloxane unit represented by ¹ SiO _1.5 or a siloxane unit represented by the formula: R ² SiO _1.5 can be mentioned. These components (A) can be used either individually or in combination of two or more.

Examples of R ¹ in the above formula include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group and heptyl group; aryl groups such as phenyl group, tolyl group, xylyl group and naphthyl group. Group; aralkyl group such as benzyl group and phenethyl group; halogenated alkyl group such as chloromethyl group, 3-chloropropyl group and 3,3,3-trifluoropropyl group. In addition, examples of R ² in the above formula include a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, and a heptenyl group.

The component (A) is preferably contained in the composition of the present invention in an amount of 0.01 to 25% by mass.

Component (B) The organohydrogenpolysiloxane of component (B) reacts with component (A) and acts as a crosslinking agent. There is no particular limitation on the molecular structure of the component (B), and various conventionally known organohydrogenpolysiloxanes having a linear, cyclic, branched, or three-dimensional network structure (resin-like) can be used. ..

The organohydrogenpolysiloxane as the component (B) is 2 or more, preferably 3 or more (generally 3 to 500, preferably 3 to 200, more preferably 3 to 100) per molecule. It has a hydrogen atom (that is, a hydrosilyl group or SiH group) bonded to a silicon atom. When the organohydrogenpolysiloxane as the component (B) has a linear structure, these SiH groups may be located at either one of the molecular chain terminal or the non-molecular chain terminal, or at both of them. May be

The number (degree of polymerization) of silicon atoms in one molecule of the component (B) is preferably 2 to 1,000, more preferably 3 to 300, and still more preferably 4 to 150. Further, the viscosity of the component (B) at 25° C. is preferably 0.1 to 5,000 mPa·s, more preferably 0.5 to 1,000 mPa·s, and even more preferably 5 to 500 mPa·s. .. The viscosity (absolute viscosity) of the organopolysiloxane of the component (B) described in the present specification is a value at 25° C. measured with a model number PC-1TL (10 rpm) manufactured by Malcolm Co., Ltd.

Examples of the component (B) include the following average composition formula (1):
R ³ _a H _b SiO _(4-ab)/2 (1)
(In the formula, R ³ is an unsubstituted or substituted monovalent hydrocarbon group having a carbon atom number of preferably 1 to 14, and more preferably 1 to 10, excluding an aliphatic unsaturated group, bonded to a silicon atom. And a and b are preferably 0.7≦a≦2.1, 0.001≦b≦1.0, and 0.8≦a+b≦3.0, and more preferably 0.9≦a. A positive number that satisfies ≦2.0, 0.01≦b≦1.0, and 1.0≦a+b≦2.5)
The organohydrogenpolysiloxane represented by

Examples of R ³ include a methyl group, an ethyl group, a propyl group, an isoprovir group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a neopentyl group, a hexyl group, a cyclohexyl group, an octyl group, a nonyl group, Alkyl group such as decyl group; aryl group such as phenyl group, tolyl group, xylyl group, naphthyl group; aralkyl group such as benzyl group, phenylethyl group, phenylpropyl group; some of hydrogen atoms in these hydrocarbon groups or A group in which all of them are substituted with a halogen atom such as fluorine, bromine or chlorine, for example, a chloromethyl group, a 3-chloropropyl group, a bromoethyl group, a 3,3,3-trifluoropropyl group and the like can be mentioned, and an alkyl group is preferable. , An aryl group, and more preferably a methyl group or a phenyl group.

The component (B) can be obtained by a known production method. As a general production method, for example, 1,3,5,7-tetramethyl-1,3,5,7-tetrahydrocyclotetrasiloxane (in some cases, the cyclotetrasiloxane and octamethylcyclotetrasiloxane And a siloxane compound serving as a terminal group source such as hexamethyldisiloxane and 1,3-dihydro-1,1,3,3-tetramethyldisiloxane, or octamethylcyclotetrasiloxane and 1,3 -A method of equilibrating dihydro-1,1,3,3-tetramethyldisiloxane with a catalyst such as sulfuric acid, trifluoromethanesulfonic acid or methanesulfonic acid at a temperature of about -10 to +40°C. To be

Specific examples of the component (B) include 1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, tris(dimethylhydrogensiloxy)methylsilane and tris(dimethylhydro). Gensiloxy) phenylsilane, dimethylsiloxy group-blocked methylhydrogenpolysiloxane at both ends of the molecular chain, dimethylsiloxy group-blocked dimethylsiloxane at both ends of the molecular chain, methylhydrogensiloxane copolymer, trimethylsiloxy group-blocked dimethylsiloxane at both ends of the molecular chain Methyl hydrogen siloxane/methyl phenyl siloxane copolymer, dimethyl hydrogen siloxy group-blocked dimethyl polysiloxane at both molecular chain ends, dimethyl hydrogen siloxy group dimethyl polysiloxane/methyl hydrogen siloxane copolymer at both molecular chain ends, molecular chain Dimethylhydrogensiloxy group-blocked dimethylsiloxane/methylphenylsiloxane copolymer with both terminals, Molecular chain Both-end dimethylhydrogensiloxy group-blocked methylphenylpolysiloxane, Formula: R ¹ ₃ SiO _0.5 (R ¹ is defined as component (A) An organopolysiloxane copolymer comprising a siloxane unit represented by the formula: R ¹ ₂ HSiO _0.5 and a siloxane unit represented by the formula: SiO ₂ , An organopolysiloxane copolymer comprising a siloxane unit represented by R ¹ ₂ HSiO _0.5 and a siloxane unit represented by the formula: SiO ₂ , a siloxane unit represented by the formula: R ¹ HSiO and a formula: R ¹ SiO _1.5 And an organopolysiloxane copolymer comprising a siloxane unit represented by the formula: HSiO _1.5 . These components (B) can be used alone or in combination of two or more.

The amount of the component (B) blended is such that the amount of hydrogen atoms (SiH groups) bonded to silicon atoms in the component (B) is 0.2 to 10 mol, preferably 1 mol of the alkenyl group in the entire composition. The amount is in the range of 1.0 to 8.0 mol. At this time, the ratio of the alkenyl group bonded to the silicon atom in the component (A) to the alkenyl group present in the entire composition is preferably 50 to 100 mol %, more preferably 80 to 100 mol %. When only component (A) is present as a component having an alkenyl group in the entire composition, the amount of SiH groups in the component (B) per mole of alkenyl groups bonded to silicon atoms in the component (A). Is 0.5 to 10 moles, preferably 1.0 to 8.0 moles. If the blending amount of the component (B) is too small, the composition may not be sufficiently cured, and conversely if the blending amount is too large, the resulting cured product (silicone rubber) may have extremely poor heat resistance.

Component (C) The hydrosilylation reaction catalyst of component (C) may be any catalyst that promotes the addition reaction between the alkenyl group in component (A) and the SiH group in component (B). You may. For example, platinum-based catalysts such as chloroplatinic acid, alcohol-modified chloroplatinic acid, coordination compounds of chloroplatinic acid with olefins, vinyl siloxanes or acetylene compounds; palladium-based catalysts such as tetrakis(triphenylphosphine)palladium; chlorotris( A rhodium-based catalyst such as triphenylphosphine)rhodium is used as the component (C), but a platinum-based catalyst such as a platinum-divinyltetramethyldisiloxane complex is particularly preferable.

The compounding amount of the component (C) is not particularly limited as long as it is an effective amount as a catalyst for the hydrosilylation reaction, but is based on the total amount of the components (A) and (B) in terms of the catalytic metal element on a mass basis. Is preferably 0.1 to 2,000 ppm, more preferably 1 to 1,500 ppm. When the addition amount is within this range, the addition reaction is sufficiently promoted, the curing is sufficient, and it is economically advantageous. The type of metal catalyst is not particularly limited as long as it is a metal having an effective activity as a catalyst for hydrosilylation reaction, but platinum or the like having an activity of splitting hydrogen gas into atoms is useful.

Component (D) Component (D) is a silver powder having a tap density of 3.0 g/cm ³ or more, a specific surface area of 2.0 m ² /g or less, and an aspect ratio of 1 to 30.
If the tap density of the silver powder of the component (D) is less than 3.0 g/cm ³ , the filling rate of the composition of the component (D) cannot be increased and the viscosity of the composition increases, resulting in poor workability. Therefore, the range of 3.0 g/cm ³ to 8.0 g/cm ³ is preferable, the range of 4.5 g/cm ³ to 8.0 g/cm ³ is more preferable, and the range of 5.5 g/cm ³ to 8.0 g is preferable. The range of /cm ³ is more preferable.
If the specific surface area of the silver powder of the component (D) is larger than 2.0 m ² /g, the filling rate of the composition of the component (D) cannot be increased and the viscosity of the composition increases, resulting in poor workability. preferably in the range of 0.08m ² /g~2.0m ² / g to become, more preferably in the range of ^{0.08m 2 /g~1.5m 2 / g, 0.08m} 2 /g~1.0m 2 The range of /g is more preferable.
The tap density described in the present specification was obtained by weighing 100 g of silver powder, gently dropping the silver powder into a 100 ml graduated cylinder with a funnel, and then placing the cylinder on a tap density measuring device to set a drop distance of 20 mm at 60 times/ It is a value calculated from the volume of the silver powder compressed by dropping 600 times at the speed of a minute.
As for the specific surface area, about 2 g of silver powder was sampled, degassed at 60±5° C. for 10 minutes, and then the total surface area was measured by an automatic specific surface area measuring device (BET method). After that, the sample amount is measured and calculated by the following formula (2).

Specific surface area (m ² /g)=total surface area (m ² )/sample amount (g) (2)

The aspect ratio of the silver powder of the component (D) is 1 to 30, preferably 2 to 20, and more preferably 3 to 15. The aspect ratio means the ratio of the major axis and the minor axis of the particle (major axis/minor axis). As a measuring method, for example, an electron micrograph of the particle is taken, and the major axis and the minor axis of the particle can be measured and calculated from this photograph. The size of the particles can be measured by an electron micrograph from the upper surface, and the larger diameter is measured from the electron micrograph of the upper surface as the major axis. The minor axis becomes the particle thickness with respect to the major axis. Particle thickness cannot be measured by electron micrographs from the top. To measure the thickness of a particle, when taking an electron micrograph, attach the sample stage on which the particle is mounted with an inclination, take an electron micrograph from the top, and correct the angle of the sample stage to correct the particle. The thickness of the can be calculated. Specifically, after taking several pictures magnified several thousand times with an electron microscope, the major axis and the minor axis of 100 particles are arbitrarily measured, and the ratio of the major axis and the minor axis (major axis/minor axis) is calculated. The aspect ratio was calculated and the average value was calculated.

The particle size of the silver powder as the component (D) is not particularly limited, but the average particle size is preferably in the range of 0.2 to 30 μm, particularly preferably 1.0 to 20 μm. The average particle size is 1 to 2 cups of silver powder placed in a 100 ml beaker with a microspatella, about 60 ml of isopropyl alcohol is added, and the silver powder is dispersed for 1 minute with an ultrasonic homogenizer, and then the volume is measured by a laser diffraction particle size analyzer. It is a standard volume average diameter [MV]. The measurement time was 30 seconds.

The method for producing the silver powder used in the present invention is not particularly limited, and examples thereof include an electrolytic method, a pulverizing method, a heat treatment method, an atomizing method, and a reducing method.
The silver powder produced by the above method may be used as it is, or may be crushed and used in a range satisfying the above numerical range. When pulverizing the silver powder, the device is not particularly limited, and known devices such as a stamp mill, a ball mill, a vibration mill, a hammer mill, a rolling roller, and a mortar can be used. Of these, a stamp mill, a ball mill, a vibration mill and a hammer mill are preferable.

The blending amount of the component (D) is 300 to 11,000 parts by mass with respect to 100 parts by mass of the component (A). When the compounding amount of the component (D) is less than 300 parts by mass relative to 100 parts by mass of the component (A), the thermal conductivity of the resulting composition is poor, and when it is more than 11,000 parts by mass, the fluidity of the composition is high. And the handleability of the composition deteriorates. The blending amount of the component (D) is preferably 300 to 5,000 parts by mass, more preferably 500 to 5,000 parts by mass, relative to 100 parts by mass of the component (A).

Component (E) The component (E) is palladium powder having an average particle size of 1 nm to 100 nm or crystalline silica, amorphous silica or carbon carrying the palladium powder. The heat-conductive silicone composition of the present invention contains a very small amount of a fine powder of palladium in a specific particle size range or a carrier having the palladium powder, so that hydrogen gas generated during the curing reaction of the composition is converted into palladium. The powder is adsorbed and the cured product has good appearance and physical properties without impairing the thermal conductivity. The average particle diameter of the palladium powder is 1 nm to 100 nm, preferably 5 nm to 70 nm, and more preferably 10 nm to 50 nm. If the average particle size is less than 1 nm, the blending will be inconvenient, and if the average particle size is more than 100 nm, the hydrogen gas adsorption efficiency with respect to the blending amount will be low, resulting in poor cost performance. The average particle size of the palladium powder is a value obtained by taking electron micrographs of the particles, taking a few thousands of magnified photographs, and then measuring the major axis of 100 particles arbitrarily.

The (E) component palladium powder may be supported on crystalline silica, amorphous silica or carbon. Examples of the carrier that supports palladium include amorphous silica such as dry silica and wet silica, crystalline silica, and carbon. The fumed silica may be fumed silica. The average particle size of silica is preferably 0.5 μm to 100 μm. When the average particle size is less than 0.5 μm, the viscosity of the composition increases and the handleability deteriorates, and when the average particle size is more than 100 μm, the formation of a heat conduction path is hindered and the thermal performance deteriorates. .. The average particle size of silica as a carrier in the component (E) was taken by taking electron micrographs of the particles and taking several thousands of magnified photographs, after which the major axis of 100 particles was arbitrarily measured. It is a value. Further, the average primary particle diameter of carbon as a carrier in the component (E) is preferably 0.5 μm to 100 μm. When the average primary particle size is less than 0.5 μm, the viscosity of the composition increases and the handling property deteriorates. When the average primary particle size is more than 100 μm, the formation of heat conduction paths is hindered and the thermal performance is improved. It may decrease. The average primary particle diameter of carbon in the component (E) is a value obtained by taking electron micrographs of the particles, taking a few thousands of magnified photographs, and then measuring the major axis of 100 particles arbitrarily. Is. The particle diameter of the crystalline silica in the component (E) is a volume-based volume average diameter [MV] measured by Microtrac MT330OEX manufactured by Nikkiso Co., Ltd.

The palladium powder in the component (E) preferably has a melting point peak in the range of 1553°C to 1557°C as measured by the thermal arrest method.

There is no particular limitation on the method of blending component (E). For example, the component (E) may be added to and dispersed in another component as it is. Further, the component (E) may be dispersed in a suitable solvent and then added to other components. Furthermore, the component (E) is mixed with an appropriate dispersion liquid (eg, organosiloxane), and then uniformly dispersed using a device such as a three-roll mill, and the paste mixture obtained is added to other components. -May be dispersed.

The blending amount of the component (E) is usually 0.00001 to 100 parts by mass of the component (A) with respect to the amount of palladium powder (if the palladium powder is supported on a carrier, the amount of supported palladium powder). The amount is 0.05 parts by mass, preferably 0.0001 to 0.001 parts by mass, more preferably 0.0005 to 0.001 parts by mass. If the blending amount is too small, it may not be possible to impart a good effect of suppressing bubble generation to the composition of the present invention, and if the blending amount is too large, it inhibits the formation of a heat conduction path, resulting in a thermal performance. May decrease.

Other Components The thermally conductive silicone composition of the present invention may contain the following components as optional components in addition to the components (A) to (E).

Curing reaction control agent In the composition of the present invention, all the conventionally known curing, which is said to have a curing suppressing effect on the addition reaction catalyst, as an optional component in addition to the above-mentioned components (A) to (E) A reaction control agent can be used. Examples of such compounds include phosphorus-containing compounds such as triphenylphosphine, nitrogen-containing compounds such as tributylamine, tetramethylethylenediamine and benzotriazole, sulfur-containing compounds, and acetylene-based compounds such as 1-ethynyl-1-cyclohexanol. , Triallyl isocyanuric acid, hydroperoxy compounds, maleic acid derivatives and the like. The degree of the curing retarding effect of the curing reaction control agent greatly differs depending on the chemical structure of the curing reaction control agent. Therefore, the addition amount of the curing reaction control agent should be adjusted to an optimum amount for each curing reaction control agent to be used, but such adjustment can be easily performed by a method well known to those skilled in the art. Generally, if the amount added is too small, the long-term storage stability of the composition of the present invention cannot be obtained at room temperature, and if the amount added is too large, the curing of the composition is inhibited.

As the inorganic compound powder and/or organic compound material other than the component (D) and the component (E), as the inorganic compound powder and/or the organic compound material other than the component (D) and the component (E),
Metal powders such as aluminum, gold, copper, nickel, indium, gallium, and metal silicon;
Diamond powder;
Carbon materials such as carbon fiber, graphene, graphite, carbon nanotube, carbon black;
Metal oxide powder such as zinc oxide, titanium oxide, magnesium oxide, alumina, iron oxide, silicon dioxide (fumed silica, crystalline silica, precipitated silica, etc.);
Metal hydroxide powder such as aluminum hydroxide;
Nitride powder such as boron nitride and aluminum nitride;
Carbonates such as magnesium carbonate, calcium carbonate and zinc carbonate;
Hollow filler; silsesquioxane; layered mica; diatomaceous earth; glass fiber; silicone rubber powder; silicone resin powder and the like.
Among these, those having high thermal conductivity are preferable. As the inorganic compound powder and/or organic compound material having high thermal conductivity, aluminum powder, zinc oxide powder, titanium oxide powder, magnesium oxide powder, alumina powder, aluminum hydroxide powder, boron nitride powder, aluminum nitride powder, diamond powder. , Gold powder, copper powder, carbon powder, nickel powder, indium powder, gallium powder, metal silicon powder, silicon dioxide powder, carbon fiber, graphene, graphite and carbon nanotube. These may be used alone or in combination of two or more.

The surface of these inorganic compound powders and organic compound materials may be subjected to hydrophobic treatment with organosilane, organosilazane, organopolysiloxane, organofluorine compound, etc., if necessary. If the average particle size of the inorganic compound powder and the organic compound material is smaller than 0.5 μm or larger than 100 μm, the filling rate in the resulting composition will not be increased, so that the range of 0.5 to 100 μm is preferable, and particularly 1 The range of up to 50 μm is preferred. Further, if the fiber length of the carbon fiber is smaller than 10 μm or larger than 500 μm, the filling rate into the composition obtained cannot be increased, so that it is preferably in the range of 10 to 500 μm, particularly preferably in the range of 30 to 300 μm.

When the total content of the inorganic compound powder and the organic compound material is more than 3,000 parts by mass with respect to 100 parts by mass of the component (A), the fluidity of the composition becomes poor and the handleability of the composition becomes poor. The amount is preferably ˜3,000 parts by mass, particularly preferably 5 to 2,000 parts by mass.

Further, the composition of the present invention, as long as the object of the present invention is not impaired, as other optional components, for example, an organopolysiloxane containing one hydrogen atom or an alkenyl group bonded to a silicon atom in one molecule, Includes organopolysiloxanes containing neither hydrogen atoms nor alkenyl groups bonded to silicon atoms, organic solvents, heat resistance imparting agents, flame retardancy imparting agents, plasticizers, thixotropy imparting agents, dyes, fungicides, etc. May be

The method for producing the thermally conductive silicone composition of the present invention may be according to a conventionally known method for producing a silicone composition, and is not particularly limited. For example, the above components (A) to (E) and, if necessary, other components are added to Trimix, Twinwin, Planetary mixer (all are mixers manufactured by Inoue Seisakusho Co., Ltd., registered trademark), Ultramixer (Mizuho). It can be produced by mixing for 10 minutes to 4 hours with a mixer such as Kogyo Co., Ltd. mixer, Hibis Dispermix (Primix Co., Ltd. mixer, registered trademark). Moreover, you may mix, heating as needed at the temperature of the range of 50-200 degreeC.

The heat conductive silicone composition of the present invention preferably has an absolute viscosity measured at 25° C. of 10 to 600 Pa·s, more preferably 15 to 500 Pa·s, and more preferably 15 to 400 Pa·s. Is more preferable. When the absolute viscosity is within the above range, a good grease can be provided and the workability of the composition is excellent. The absolute viscosity can be obtained by preparing each component in the above-mentioned blending amount. The absolute viscosity is a result measured using a model number PC-1TL (10 rpm) manufactured by Malcolm Co., Ltd.

The heat conductive silicone composition of the present invention is cured by heating the heat conductive silicone composition obtained as described above to 80° C. or higher under a pressure of 0.01 MPa or higher. The properties of the cured product thus obtained are not limited, and examples thereof include gel, low hardness rubber, and high hardness rubber.

Semiconductor Device The semiconductor device of the present invention is characterized in that the heat conductive silicone composition of the present invention is interposed between the surface of the heat generating electronic component and the heat radiator. The thermally conductive silicone composition of the present invention is preferably interposed in a thickness of 10 to 500 μm.
A typical structure is shown in FIG. 1, but the present invention is not limited to this. The heat conductive silicone composition of the present invention is shown in 3 of FIG.

As a method for producing the semiconductor device of the present invention, the heat conductive silicone composition of the present invention is heated to 80° C. or higher while a pressure of 0.01 MPa or higher is applied between the heat-generating electronic component and the radiator. A heating method is preferred. At this time, the applied pressure is preferably 0.01 MPa or more, particularly preferably 0.05 MPa to 100 MPa, further preferably 0.1 MPa to 100 MPa. The heating temperature needs to be 80° C. or higher. The temperature is preferably 100° C. to 300° C., more preferably 120° C. to 300° C., and further preferably 140° C. to 300° C.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples for the purpose of clarifying the effects of the present invention, but the present invention is not limited thereto.
The test for the effect of the present invention was conducted as follows.

〔viscosity〕
The absolute viscosity of the composition was measured at 25° C. using a Malcolm viscometer (type PC-1TL).

〔Thermal conductivity〕
The compositions of Examples 1 to 14 and Comparative Examples 1 to 7 shown in the table below were poured into a mold having a thickness of 6 mm and heated to 150° C. under a pressure of 0.35 MPa, and then Kyoto Electronics Industry Co., Ltd. ) Manufactured by TPS-2500S, the thermal conductivity was measured at 25°C.

[Bubbling test]
Each composition of Examples 1 to 26 and Comparative Examples 1 to 13 was weighed on a slide glass to be 0.1 g, sandwiched with another slide glass, and at a pressure of 25 psi (0.17 MPa) at 25° C. Hold for 15 minutes. Then, it was heat-treated at 150° C. for 1 hour without pressure to be cured, and the degree of foaming was visually confirmed. In this bubble generation test, curing was carried out without pressure for the purpose of confirming the presence or absence of bubbles generated from the composition.

Prepared the following components that form the composition.

(A) Component A-1: Dimethylpolysiloxane having both ends blocked with dimethylvinylsilyl groups and a kinematic viscosity at 25° C. of 600 mm ² /s.

(B) Component B-1: Organohydrogenpolysiloxane represented by the following formula (viscosity at 25° C. is 30 mm ² /s)

(C) Component C-1: (Platinum catalyst): A-1 solution of platinum-divinyltetramethyldisiloxane complex, containing 1 wt% as platinum atom

(D) Component D-1: Silver powder having a tap density of 6.6 g/cm ³ , a specific surface area of 0.28 m ² /g and an aspect ratio of 8 D-2: a tap density of 6.2 g/cm ³ , ratio Silver powder having a surface area of 0.48 m ² /g and an aspect ratio of 13 D-3: Silver powder having a tap density of 3.0 g/cm ³ , a specific surface area of 2.0 m ² /g and an aspect ratio of 30

(E) Component E-1: Palladium powder having an average particle diameter of 5 nm E-2: 0.8 wt% palladium powder-supported fumed silica (the average particle diameter of the palladium powder is 90 nm, and the fumed silica used for supporting the powder) Has an average particle size of 5 μm.)
E-3: 0.5 wt% palladium powder-supported dry silica (the average particle size of the palladium powder is 7 nm, and the specific surface area of the dry silica used for the support is 130 m ² /g).
E-4: 1.0 wt% palladium powder-carrying carbon (average particle size of palladium powder is 2 nm, and primary particle size of carbon used for supporting is about 48 nm)
E-5 (comparative example): Palladium powder having an average particle diameter of 110 nm E-6 (comparative example): Palladium powder having an average particle diameter of 0.5 nm E-7: 0.8 wt% palladium powder-supporting crystalline silica (The average particle size of the palladium powder is 5 nm, and the average particle size of the crystalline silica used for supporting is 5 μm.)
E-8: 0.8 wt% palladium powder-supporting crystalline silica (the average particle size of the palladium powder is 90 nm, and the average particle size of the crystalline silica used for supporting is 5 μm)
E-9: 1.0 wt% Palladium powder-supporting crystalline silica (The average particle size of the palladium powder is 2 nm, and the average particle size of the crystalline silica used for supporting is about 5 μm.)
E-10 (Comparative Example): 0.8 wt% palladium powder-supporting crystalline silica (palladium powder has an average particle size of 110 nm, and the crystalline silica used for supporting has an average particle size of 5 μm).
E-11 (Comparative Example): 0.8 wt% palladium powder-supporting crystalline silica (palladium powder has an average particle size of 0.5 nm, and the crystalline silica used for supporting has an average particle size of 5 μm).

Component (F): Curing reaction inhibitor F-1: 1-ethynyl-1-cyclohexanol

Examples 1-26 and Comparative Examples 1-13
The compositions shown in Tables 1 to 6 below were mixed as follows to obtain compositions of Examples 1 to 26 and Comparative Examples 1 to 13.
That is, the components (A) and (D) are taken in a 5 liter planetary mixer (manufactured by Inoue Seisakusho Co., Ltd.), and the components (C), (E) and (F) are added and mixed at 25° C. for 1.5 hours. did. Next, the component (B) was added and mixed so as to be uniform.

In Comparative Examples 3 and 10 containing a small amount of the component (E) and Comparative Example 6 containing no component (E), foaming was confirmed in the cured product. Further, in Comparative Examples 4 and 11 in which the amount of the component (E) was large, the thermal conductivity of the cured product was low and the desired thermal performance could not be obtained. Further, in Comparative Examples 5 and 7 using the component (E) in which the average particle diameter of the palladium powder was outside the range of the present invention, foaming was confirmed in the cured product. Further, in Comparative Examples 12 and 13 using the component (E) in which the average particle size of the palladium powder supported on the crystalline silica was outside the range of the present invention, foaming was confirmed in the cured product.
On the other hand, the cured product of the thermally conductive silicone composition of the present invention in which a specific amount of the component (E) having palladium powder in a specific particle size range was blended was excellent in thermal conductivity and did not cause foaming.

1. Substrate 2. Exothermic electronic components (CPU)
3. Heat conductive silicone composition layer 4. Heat sink (lid)

Claims (3)

1. A thermally conductive silicone composition containing the following components (A), (B), (C), (D) and (E).
   (A) Organopolysiloxane containing at least two alkenyl groups bonded to silicon atoms in one molecule: 100 parts by mass (B) At least two hydrogen atoms bonded to silicon atoms (SiH groups) in one molecule Organohydrogenpolysiloxane: An amount (C) hydrosilylation reaction in which the amount of hydrogen atoms bonded to silicon atoms in the component (B) is 0.2 to 10 mol per 1 mol of alkenyl groups in the entire composition. Catalyst: Effective amount (D) Silver powder having a tap density of 3.0 g/cm ³ or more, a specific surface area of 2.0 m ² /g or less, and an aspect ratio of 1 to 30: (A) 300 to 11,000 parts by mass (E) Palladium powder having an average particle diameter of 1 nm to 100 nm with respect to 100 parts by mass of the component, or crystalline silica, amorphous silica or carbon supporting the palladium powder: (A ) Amount of palladium powder in an amount of 0.00001 to 0.05 parts by mass based on 100 parts by mass of the component
2. A semiconductor device comprising a heat-generating electronic component and a heat radiator, wherein the heat-conductive silicone composition according to claim 1 is interposed between the heat-generating electronic component and the heat radiator. apparatus.
3. A semiconductor device comprising a step of heating the heat conductive silicone composition according to claim 1 to 80° C. or higher in a state in which a pressure of 0.01 MPa or higher is applied between the heat generating electronic component and the radiator. Production method.

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