Silicone composition

Abstract

To provide a silicone composition that can yield a silicone grease having high thermal conductivity and excellent adhesiveness as compared to conventional silicone greases.SOLUTION: Provided is a silicone composition comprising: (A) an organopolysiloxane having at least two aliphatic unsaturated hydrocarbon groups per molecule and having a kinematic viscosity of 60-100,000 mm2 / s at 25°C; (B) a specific hydrolyzable organopolysiloxane; (C) at least one thermally conductive filler selected from the group consisting of metal oxides or metal nitrides; (D) a specific organohydrogen polysiloxane; (E) a specific organohydrogen polysiloxane, different from (D); (F) a specific hydrolyzable organopolysiloxane; (G) a platinum group metal catalyst; and (H) a reaction control agent.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a silicone composition. In particular, the present invention relates to a silicone composition that provides a silicone grease with high thermal conductivity, and to a silicone composition that can provide a grease that has good adhesion even when it contains a large amount of a thermally conductive filler. [Background technology]

[0002] It is widely known that electronic components such as LSIs and IC chips generate heat during use and the performance declines as a result. Various heat dissipation technologies are used as a means to solve this problem. A common method is to place a cooling member near the heat-generating part, bring them into close contact, and then dissipate heat efficiently by removing the heat from the cooling member. In this case, if there is a gap between the heat-generating part and the cooling member, the heat conductivity will decrease due to the presence of air with poor thermal conductivity, and the temperature of the heat-generating part will not drop sufficiently. In order to prevent this phenomenon, heat dissipation materials with good thermal conductivity and conformability to the surface of the part, such as heat dissipation grease and heat dissipation sheets, are used to prevent the presence of air.

[0003] Some heat dissipation greases have adhesive properties to firmly bond the semiconductor chip and the heat spreader. If the semiconductor chip and the heat spreader are not sufficiently bonded through the grease, the heat dissipation performance may not be fully exhibited, which may cause a significant decrease in performance. Therefore, it is important to firmly bond the semiconductor chip and the heat spreader with the grease. However, in order to improve the thermal conductivity of the heat dissipation grease, it is also necessary to fill a large amount of thermally conductive filler. If a large amount of thermally conductive filler is filled into the grease, there is a problem that the adhesiveness of the resulting cured product decreases. It is widely known that if the adhesiveness decreases, the cured product cannot follow the distortion of the semiconductor chip due to the thermal history of heat generation and cooling, causing peeling, and in the worst case, the semiconductor chip may be damaged.

[0004] Patent Document 1 describes a thermally conductive silicone grease composition that contains as essential components an alkenyl group-containing organopolysiloxane, a thermally conductive filler, an organohydrogenpolysiloxane, an organohydrogenpolysiloxane having at least one of an alkoxysilyl group and an epoxy group, and a platinum catalyst. However, looking at the examples, none of the compositions have a thermal conductivity of more than 2.0 W / mK, which is insufficient.

[0005] Patent Document 2 describes a thermally conductive silicone grease composition containing an alkenyl group-containing organopolysiloxane, a hydrolyzable methylpolysiloxane, a thermally conductive filler, an organohydrogenpolysiloxane, a triazine ring and an alkenyl group-containing adhesive aid, and a platinum catalyst as essential components. However, looking at the examples, none of them have a thermal conductivity of more than 3.0 W / mK, which is insufficient. Patent Document 3 describes a thermally conductive silicone composition containing a silicone resin that does not have an aliphatic unsaturated hydrocarbon group, and states that the composition can provide a heat dissipating grease with high adhesive strength. However, looking at the examples, none of them have a thermal conductivity of more than 4.0 W / mK, which is insufficient.

[0006] In recent years, high-end semiconductor devices have been generating more and more heat during operation. However, conventional silicone greases have problems such as insufficient thermal conductivity or high thermal conductivity but low adhesion. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2012-067153 A [Patent Document 2] JP 2012-102283 A [Patent Document 3] JP 2016-053140 A Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a silicone composition that is capable of producing a silicone grease that has higher thermal conductivity and better adhesion than conventional silicone greases. [Means for solving the problem]

[0009] As a result of intensive research into achieving the above-mentioned object, the present inventors have discovered that a silicone composition containing an aliphatic unsaturated hydrocarbon group-containing organopolysiloxane, an organopolysiloxane having a hydrolyzable group, a thermally conductive filler, an organohydrogenpolysiloxane having a specific structure, and a platinum group metal catalyst can provide a silicone grease that has good adhesion even when it contains a large amount of thermally conductive filler, and have thus completed the present invention.

[0010] That is, the present invention provides the following silicone composition. 1. A silicone composition containing the following components (A) to (D): (A) having at least two aliphatic unsaturated hydrocarbon groups in one molecule and a kinetic viscosity at 25°C of 60 to 100,000 mm 2 / s Organopolysiloxane: 100 parts by mass (B) a hydrolyzable organopolysiloxane represented by the following general formula (1): 100 to 600 parts by mass [ka] (In the formula, R 1 are each independently an alkyl group having 1 to 6 carbon atoms, and r is an integer of 5 to 100. (C) At least one thermally conductive filler selected from the group consisting of metal oxides and metal nitrides: 4,001 to 12,000 parts by mass (D) Organohydrogenpolysiloxane represented by the following general formula (2): 1.0 to 8.0 parts by mass [ka] (In the formula, n and m are each a number greater than 0, and satisfy the conditions 5.0≦n+m≦100 and n / (n+m)≦0.5; R 2 are each independently an alkyl group having 1 to 6 carbon atoms. (E) Organohydrogenpolysiloxane represented by the following general formula (3): 1.0 to 7.0 parts by mass [ka] (In the formula, o is an integer of 1 to 8; R 3 are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or R 4 where R 3 Two or three of the groups represented by the above R 4 is a group selected from the group consisting of an epoxy group, an acryloyl group, a methacryloyl group, an ether group, and a trialkoxysilyl group, which is bonded to a silicon atom via a carbon atom or an oxygen atom. (F) a hydrolyzable organopolysiloxane represented by the following general formula (4): 1 to 30 parts by mass [ka] (In the formula, p and q are each a number equal to or greater than 1.0 and satisfy the relationship 5.0≦p+q≦100; R 5 are each independently an alkyl group having 1 to 6 carbon atoms, and R 6 is an alkenyl group having 2 to 6 carbon atoms. (G) Platinum group metal catalyst: an effective amount (H) Reaction inhibitor: 0.05 to 5.0 parts by mass 2. The silicone composition of 1, wherein the component (C) comprises the following components (C-1) to (C-3): (C-1) Aluminum nitride particles having an average particle size of 10 μm or more and less than 30 μm, and a residue when sieved through a 200 mesh wire screen of less than 1.0 mass % (C-2) Metal oxides or metal nitrides with an average particle size of 1 μm or more and less than 10 μm (C-3) Metal oxides or metal nitrides with an average particle size of 0.1 μm or more and less than 1 μm 3. A silicone composition according to 1 or 2, in which the thermal conductivity of the cured product is 4.0 W / m K or more. 4. A semiconductor device in which a cured silicone composition is interposed between a heat generating member and a cooling member, A semiconductor device, wherein the layer of the cured material is made of a cured material of any one of the compositions 1 to 3 and has a thickness of 100 μm or less. 5. A method for producing the silicone composition according to claim 2, A method for producing a silicone composition, comprising the step of previously mixing components (C-1) to (C-3) with components (A) and (B). Effect of the Invention

[0011] The silicone composition of the present invention has good adhesive properties even when it contains a large amount of thermally conductive filler, and therefore can provide a silicone grease that has high thermal conductivity and good adhesive properties. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The present invention will be described in detail below. [Component (A)] Component (A) has at least two aliphatic unsaturated hydrocarbon groups in each molecule and has a kinetic viscosity of 60 to 100,000 mm at 25°C. 2 The aliphatic unsaturated hydrocarbon group is preferably a monovalent hydrocarbon group having 2 to 8 carbon atoms and an aliphatic unsaturated bond, more preferably a monovalent hydrocarbon group having 2 to 6 carbon atoms and an aliphatic unsaturated bond, and still more preferably an alkenyl group.

[0013] Specific examples of the aliphatic unsaturated bond include alkenyl groups such as vinyl, allyl, propenyl, isopropenyl, butenyl, hexenyl, cyclohexenyl, and octenyl. Vinyl is particularly preferred. The aliphatic unsaturated hydrocarbon group may be bonded to either a silicon atom at the end of the molecular chain or a silicon atom in the middle of the molecular chain, or may be bonded to both.

[0014] The organopolysiloxane has a kinetic viscosity of 60 to 100,000 mm at 25°C. 2 / s, 100~30,000mm 2 It is preferable that the kinematic viscosity is 60 mm / s. 2 If the viscosity is less than 100,000 mm / s, the physical properties of the silicone composition may deteriorate. 2 If the kinematic viscosity exceeds 1 / s, the silicone composition may have poor extensibility. In the present invention, the kinematic viscosity is a value measured at 25°C using an Ubbelohde-type Ostwald viscometer. The molecular structure of the organopolysiloxane is not particularly limited as long as it has the above-mentioned properties, and examples of the molecular structure include linear, branched, and linear structures having a partial branch or cyclic structure.

[0015] In particular, the organopolysiloxane is preferably one having a linear structure in which the main chain is composed of repeating diorganosiloxane units and both ends of the molecular chain are blocked with triorganosiloxy groups. The linear organopolysiloxane may have a partially branched structure or a cyclic structure. The organopolysiloxane may be used alone or in combination of two or more.

[0016] The organic group other than an aliphatic unsaturated hydrocarbon group bonded to the silicon atom of the organopolysiloxane is preferably an unsubstituted or substituted monovalent hydrocarbon group having 1 to 18 carbon atoms, more preferably an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and even more preferably an unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms.

[0017] Specific examples of the unsubstituted or substituted monovalent hydrocarbon group include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, octyl, nonyl, and decyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; aralkyl groups such as benzyl, phenylethyl, and phenylpropyl; and groups in which some or all of the hydrogen atoms of these groups have been substituted with halogen atoms such as fluorine, bromine, and chlorine, or cyano groups, such as chloromethyl, chloropropyl, bromoethyl, trifluoropropyl, and cyanoethyl. Methyl groups are particularly preferred.

[0018] [(B) Component] Component (B) is a hydrolyzable organopolysiloxane represented by the following general formula (1).

[0019] [ka] (In the formula, R 1 are each independently an alkyl group having 1 to 6 carbon atoms, and r is an integer of 5 to 100.

[0020] Above R 1 represents an alkyl group having 1 to 6 carbon atoms, specific examples of which include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, and a hexyl group, of which a methyl group, an ethyl group, a propyl group, an isopropyl group, and a butyl group are preferred, and a methyl group is more preferred.

[0021] The above r is an integer of 5 to 100, preferably an integer of 10 to 60. If the value of r is smaller than the lower limit, the oil bleeding from the silicone composition may become severe, resulting in poor reliability. If the value of r is larger than the upper limit, the wettability with the filler may become insufficient.

[0022] The amount of the (B) component is 100 to 600 parts by mass, preferably 100 to 300 parts by mass, and more preferably 200 to 300 parts by mass, per 100 parts by mass of the (A) component. If the amount of the (B) component is less than the lower limit, sufficient wettability may not be exhibited. If the amount of the (B) component is more than the upper limit, bleeding from the composition becomes severe, and adhesive strength decreases.

[0023] [(C) component] The component (C) is at least one type of thermally conductive filler selected from the group consisting of metal oxides and metal nitrides. Specific examples of the component (C) include aluminum nitride powder, aluminum oxide powder, zinc oxide powder, magnesium oxide powder, etc. The component (C) may be used alone or in combination of two or more types, but is preferably at least one type selected from the group consisting of aluminum nitride powder, aluminum oxide powder, and zinc oxide powder. Furthermore, the component (C) preferably contains the following components (C-1) to (C-3). (C-1) Aluminum nitride having an average grain size of 10 μm or more and less than 30 μm (C-2) Aluminum nitride or aluminum oxide having an average particle size of 1 μm or more and less than 10 μm (C-3) Zinc oxide, aluminum nitride, or aluminum oxide having an average particle size of 0.1 μm or more and less than 1 μm When the component (C) is a combination of the above components (C-1) to (C-3), the thermally conductive filler can be loaded at a higher concentration, thereby enhancing the thermal conductivity of the resulting composition.

[0024] The component (C-1) is aluminum nitride having an average particle size of 10 μm or more and less than 30 μm, preferably 15 μm or more and less than 25 μm. By setting the average particle size in the above range, it is possible to achieve both high thermal conductivity and stability. Furthermore, the component (C-1) preferably has a residue of less than 1.0 mass% when sieved through a 200 mesh wire net, more preferably less than 0.5 mass%, and even more preferably 0.1 mass%. Furthermore, it is more preferable that the residue of the component (C-1) when sieved through a 325 mesh wire net is less than 1.0 mass%, particularly preferably less than 0.5 mass%, and most preferably 0.1 mass%. The 200 mesh wire net and 325 mesh wire net used here are wire nets specified in JIS Z 8801. By setting the residue of (C-1) when sieved through a 200 mesh wire net to less than 1.0 mass%, the thickness of the coating film of the composition interposed between the heat generating member and the cooling member in the semiconductor device can be sufficiently thin.

[0025] The shape of the (C-1) component may be crushed, polyhedral, round, or spherical, with round being preferred. In the present invention, the term "average particle size" refers to the particle size at 50% of the cumulative value in the volume-based particle size distribution determined by the laser diffraction / scattering method. Measurement by the laser diffraction / scattering method may be performed, for example, using a Microtrack particle size analyzer MT3300EX (manufactured by Nikkiso Co., Ltd.). Furthermore, in order to increase the filling property, decrease the viscosity of the composition, and prevent the settling of the filler, it is preferable to include the (C-2) component and the (C-3) component as particle sizes different from those of the (C-1). Compared to the two-component system of the (C-1) component and the (C-2) component, the three-component system of the (C-1) to (C-3) components has a lower viscosity of the composition and improves the adhesive strength when cured.

[0026] The average particle size of component (C-2) is preferably 1 to 10 μm, more preferably 2 to 8 μm, and even more preferably 3 to 7 μm. When the average particle size is 1 to 10 μm, a uniform composition can be obtained when component (C-1), component (C-2), and component (C-3) are mixed with component (A) and component (B), the viscosity of the composition can be lowered, and the adhesive strength when cured can be improved.

[0027] The average particle size of component (C-3) is preferably 0.1 to 1 μm. If component (C-3) has a particle size of 1 μm or more, the resulting silicone composition may have a high viscosity or poor extensibility.

[0028] The amount of component (C) is 4,001 to 12,000 parts by mass, and preferably 5,000 to 12,000 parts by mass, per 100 parts by mass of component (A). If the amount of the filler is less than 4,001 parts by mass, the thermal conductivity of the resulting composition may be poor, whereas if it exceeds 12,000 parts by mass, the composition may have poor extensibility.

[0029] The (C) component preferably contains 50 to 90 mass% of the (C-1) component and the (C-2) component based on the total mass of the (C) component, more preferably 50 to 80 mass%, and even more preferably 50 to 70 mass%. If the amount of the (C-1) and (C-2) components is less than 50 mass%, the thermal conductivity may decrease. If the amount of the (C-1) and (C-2) components is more than 90 mass%, the composition may not be homogeneous. The ratio of the (C-1) and (C-2) components is preferably 50:50 to 95:5 by mass, and more preferably 60:40 to 80:20. If the ratio of the (C-1) component is less than 50, the thermal conductivity may decrease. If the ratio of the (C-1) component is more than 95, the adhesive strength may decrease.

[0030] [(D) component] Component (D) is an organohydrogenpolysiloxane. In this organohydrogenpolysiloxane, the SiH groups in the molecule undergo an addition reaction with the aliphatic unsaturated hydrocarbon groups in the composition in the presence of a platinum group metal catalyst described below to form a crosslinked structure. This organohydrogenpolysiloxane is represented by the following general formula (2).

[0031] [ka] (In the formula, n and m are each a number greater than 0, and satisfy the conditions 5.0≦n+m≦100 and n / (n+m)≦0.5; R 2 are each independently an alkyl group having 1 to 6 carbon atoms.

[0032] It is essential that the organohydrogenpolysiloxane does not have a SiH group at the molecular chain end. When an organohydrogenpolysiloxane having a SiH group at the molecular chain end is used, the shelf life of the silicone composition is significantly reduced. Furthermore, n and m satisfy 5.0≦n+m≦100, and preferably satisfy 10≦n+m≦80. If n+m is less than 5.0, the physical properties of the silicone composition may be reduced, and if n+m is greater than 100, the extensibility of the silicone composition may be poor. Furthermore, n and m satisfy n / (n+m)≦0.5, and preferably satisfy n / (n+m)≦0.3. If n / (n+m) is greater than 0.5, the adhesiveness of the silicone composition may be reduced. R 2 are each independently an alkyl group having 1 to 6 carbon atoms, specific examples of which include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, etc. The organohydrogenpolysiloxane may be used alone or in combination of two or more types.

[0033] The amount of component (D) is 1.0 to 8.0 parts by mass, and preferably 1.2 to 7.0 parts by mass, per 100 parts by mass of component (A). If the amount of component (D) is less than 1.0 part by mass, the hardness of the cured product of the obtained composition may be poor and low, whereas if it exceeds 8.0 parts by mass, the hardness of the cured product of the composition may be poor and high.

[0034] [(E) component] Component (E) is an organohydrogenpolysiloxane. In this organohydrogenpolysiloxane, the SiH groups in the molecule undergo an addition reaction with the aliphatic unsaturated hydrocarbon groups in the composition in the presence of a platinum group metal catalyst described below to form a crosslinked structure and impart adhesiveness to the silicone composition. This organohydrogenpolysiloxane is represented by the following general formula (3).

[0035] [ka] (In the formula, o is an integer of 1 to 8; R 3 are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or R 4 where R 3 Two or three of the groups represented by the above R 4 is a group selected from the group consisting of an epoxy group, an acryloyl group, a methacryloyl group, an ether group, and a trialkoxysilyl group, which is bonded to a silicon atom via a carbon atom or an oxygen atom.

[0036] Above R 3 are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or R 4 where R 3 Two or three of the groups represented by the above R 4 is a group selected from the group consisting of an epoxy group, an acryloyl group, a methacryloyl group, an ether group, and a trialkoxysilyl group, which is bonded to a silicon atom via a carbon atom or an oxygen atom, and has the effect of imparting adhesiveness to the silicone composition. 3 are each independently an alkyl group having 1 to 6 carbon atoms, specific examples of which include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, etc. The organohydrogenpolysiloxane may be used alone or in combination of two or more types.

[0037] The amount of component (E) is 1.0 to 7.0 parts by mass, preferably 1.5 to 7.0 parts by mass, based on 100 parts by mass of component (A). If the amount of component (D) is less than 1.0 part by mass, the adhesive strength of the resulting composition will be low. If it exceeds 7.0 parts by mass, the hardness of the cured product of the composition may be low.

[0038] [Component (F)] Component (F) is a hydrolyzable organopolysiloxane that provides wettability with the thermally conductive filler and adhesiveness to the silicone composition. The hydrolyzable organopolysiloxane is represented by the following general formula (4).

[0039] [ka] (In the formula, p and q are each a number equal to or greater than 1.0 and satisfy the relationship 5.0≦p+q≦100; R 5 are each independently an alkyl group having 1 to 6 carbon atoms, and R 6 is an alkenyl group having 2 to 6 carbon atoms.

[0040] p and q satisfy 5.0≦p+q≦100, and preferably 10≦p+q≦60. If p+q is less than 5.0, the oil bleeding from the silicone composition may become severe, resulting in poor reliability. If p+q is more than 100, the wettability with the filler may become insufficient.

[0041] R 5 are each independently an alkyl group having 1 to 6 carbon atoms, specific examples of which include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, and a hexyl group. 6 is an alkenyl group having 2 to 6 carbon atoms, specific examples of which include a vinyl group, an allyl group, a propenyl group, an isopropenyl group, a butenyl group, a hexenyl group, and a cyclohexenyl group.

[0042] The amount of the (F) component is 1 to 30 parts by mass, preferably 3 to 25 parts by mass, and more preferably 5 to 20 parts by mass, based on 100 parts by mass of the (A) component. If the amount of the (F) component is less than the lower limit, sufficient wettability and adhesiveness may not be exhibited. If the amount of the (F) component is more than the lower limit, bleeding from the cured product obtained using the composition of the present invention may become severe.

[0043] [(G) component] The component (G) is a platinum group metal catalyst, and functions to promote the above-mentioned addition reaction. The platinum group metal catalyst may be a conventionally known catalyst used in addition reactions. Examples include platinum-based, palladium-based, and rhodium-based catalysts, among which platinum or platinum compounds, which are relatively easy to obtain, are preferred. Specific examples of platinum-based catalysts include platinum alone, platinum black, chloroplatinic acid, platinum-olefin complexes, platinum-alcohol complexes, platinum coordination compounds, and the like. The platinum-based catalysts may be used alone or in combination of two or more.

[0044] The amount of the (G) component should be an effective amount as a catalyst, that is, an effective amount required to promote the addition reaction and cure the composition of the present invention. In particular, the amount is preferably 0.1 to 500 ppm, more preferably 1 to 200 ppm, based on the mass of platinum group metal atoms relative to the entire composition. If the amount of the catalyst is less than the lower limit, the catalytic effect may not be obtained. Moreover, if the amount exceeds the upper limit, the catalytic effect is not increased and it is uneconomical, so it is not preferable.

[0045] [(H) component] The component (H) is a reaction inhibitor that suppresses the progress of the hydrosilylation reaction at room temperature and functions to extend the shelf life and pot life. The reaction inhibitor may be a known reaction inhibitor used in addition curing silicone compositions. Specific examples of reaction inhibitors include acetylene compounds such as acetylene alcohols (e.g., ethynylmethyldecylcarbinol, 1-ethynyl-1-cyclohexanol, 3,5-dimethyl-1-hexyn-3-ol); various nitrogen compounds such as tributylamine, tetramethylethylenediamine, and benzotriazole; organic phosphorus compounds such as triphenylphosphine; oxime compounds; and organic chloro compounds.

[0046] The amount of the (H) component is 0.05 to 5.0 parts by mass, preferably 0.1 to 1.0 parts by mass, relative to 100 parts by mass of the (A) component. If the amount of the reaction inhibitor is less than 0.05 parts by mass, the desired sufficient shelf life and pot life may not be obtained, and if it is more than 5.0 parts by mass, the curing property of the silicone composition may be reduced. In addition, the inhibitor may be used by diluting it with organo(poly)siloxane, toluene, etc., in order to improve its dispersibility in the silicone composition.

[0047] [Other ingredients] The silicone composition of the present invention may contain a non-reactive organo(poly)siloxane such as methylpolysiloxane in order to adjust the elastic modulus and viscosity of the composition.Furthermore, in order to prevent deterioration of the silicone composition, a conventionally known antioxidant such as 2,6-di-t-butyl-4-methylphenol may be contained as necessary.Furthermore, dyes, pigments, flame retardants, anti-settling agents, thixotropy improvers, etc. may be blended as necessary.

[0048] Next, the method for producing the thermally conductive silicone composition of the present invention will be described, but is not limited to this. The method for producing the thermally conductive silicone composition of the present invention includes the step of producing a silicone composition containing the above-mentioned components (A) to (H).

[0049] [Preparation of silicone composition] The method for producing the silicone composition of the present invention may be according to the conventional method for producing silicone grease compositions, and is not particularly limited. For example, the silicone composition can be produced by mixing the above-mentioned (A) to (J) components, and other components as necessary, with a mixer such as Trimix, Twinmix, Planetary Mixer (all registered trademarks of mixers manufactured by Inoue Seisakusho Co., Ltd.), Ultramixer (registered trademarks of mixers manufactured by Mizuho Kogyo Co., Ltd.), or Hivis Dispermix (registered trademarks of mixers manufactured by Tokushu Kika Kogyo Co., Ltd.). In addition, when using components (C-1) to (C-3) as component (C), it is preferable to mix components (C-1) to (C-3) with component (A) and component (B) in advance from the viewpoint of obtaining a uniform composition.

[0050] The silicone composition of the present invention preferably has an absolute viscosity measured at 25°C of 3.0 to 800 Pa·s, and more preferably 150 to 450 Pa·s. If the absolute viscosity is less than 3.0 Pa·s, workability may be impaired, such as difficulty in maintaining the shape. If the absolute viscosity exceeds 800 Pa·s, workability may be impaired, such as difficulty in discharging. The above absolute viscosity can be obtained by adjusting the blending of the above-mentioned components. In the present invention, the absolute viscosity is a value measured at 25°C using a Malcolm viscometer (rotor A at 10 rpm, shear rate 6 [1 / s]).

[0051] The silicone composition of the present invention preferably has a thermal conductivity measured at 25° C. of at least 4.0 W / m° C., more preferably at least 5.0 W / m° C., and even more preferably at least 6.0 W / m° C. In the present invention, the thermal conductivity is a value measured using a TPA-501 manufactured by Kyoto Electronics Manufacturing Co., Ltd. The coating thickness of the silicone composition, as measured by the following method, is preferably 100 μm or less, more preferably 75 μm or less, and even more preferably 65 μm or less. By having such properties, for example, when applied between a heat generating member and a cooling member of a semiconductor device, a thin coating film can be formed, and by curing the silicone composition, a thin cured layer can be obtained.

[0052] In the present invention, the coating thickness of the silicone composition is measured as follows: Each composition is sandwiched between two circular aluminum plates (diameter 12.6 mm, thickness 1 mm) to a thickness of 100 μm, and a pressure of 0.1 MPa is applied at 25° C. for 60 minutes to prepare a test piece. The thickness of the test piece is measured with a known micrometer, and the thickness of the composition is determined by subtracting the thickness of the aluminum plate, which has been measured beforehand.

[0053] [Cured product] The silicone composition of the present invention can be suitably used to transfer heat from a heat generating component to a cooling component by being interposed between electronic components such as LSI and other heat generating components, and can be used in the same manner as conventional heat conductive silicone grease. For example, the silicone composition of the present invention can be cured by heat generated from a heat generating component such as an electronic component. In addition, the silicone composition of the present invention may be actively cured by heating after being applied. This makes it possible to provide a semiconductor device in which a cured product of the silicone composition of the present invention is interposed between a heat generating component and a cooling component. The curing conditions for the heat curing of the silicone composition of the present invention are not particularly limited, but are usually 80 to 200°C, preferably 100 to 180°C, and 30 minutes to 4 hours, preferably 30 minutes to 2 hours.

[0054] In addition, from the viewpoint of improving adhesion and heat dissipation performance, the thickness of the layer of the cured product of the ricone composition interposed between the heat-generating component and the cooling component is preferably 100 μm or less, more preferably 75 μm or less, and even more preferably 65 μm or less.

[0055] The thickness of the cured layer can be adjusted by adjusting the thickness of the coating of the silicone composition.In addition, when the silicone composition is applied between the heat generating member and the cooling member, the thickness of the coating can be made thinner by pressing the heat generating member and the cooling member at a predetermined temperature and pressure, and it is expected that the heat dissipation property can be further improved while maintaining good adhesion.

[0056] [Tensile shear adhesive strength] The tensile shear adhesive strength of the cured product of the silicone composition of the present invention is preferably 0.05 to 3.0 MPa, and the method for measuring an adhesive strength of 0.1 to 2.0 MPa is as described in the Examples below.

[0057] The silicone composition of the present invention has high thermal conductivity, good adhesion, and is capable of forming a thin coating film, making it particularly suitable for use as a heat dissipating grease for high-end semiconductor devices and the like. EXAMPLES

[0058] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the following, the kinematic viscosity is a value measured at 25°C using an Ubbelohde-type Ostwald viscometer (manufactured by Shibata Scientific Products Co., Ltd.).

[0059] [Component (A)] A-1: Both ends are blocked with dimethylvinylsilyl groups, and the kinetic viscosity at 25°C is 600mm 2 / s Dimethylpolysiloxane A-2: Both ends are blocked with dimethylvinylsilyl groups, and the kinetic viscosity at 25°C is 400mm 2 / s Dimethylpolysiloxane [(B) Component] B-1: Polyorganosiloxane having a hydrolyzable group represented by the following average formula: [ka] [(C) component] C-1-1: Round aluminum nitride powder with an average particle size of 19.6 μm (0.02% by mass on sieving with a 200 mesh wire screen, 0.9% by mass on combing with a 325 mesh wire screen) C-1-2: Round aluminum nitride powder with an average particle size of 22.6 μm (0.04% by mass on sieve using 200 mesh wire screen, 0.01% by mass on comb using 325 mesh wire screen) C-1-3: Round aluminum nitride powder with an average particle size of 15.6 μm (0.01% by mass on sieving with a 200 mesh wire screen, 0.70% by mass on combing with a 325 mesh wire screen) C-1-4: Round aluminum nitride powder with an average particle size of 10.6 μm (0.01% by mass of sieve residue on 200 mesh wire screen, 0.01% by mass of comb residue on 325 mesh wire screen) C-1-5: Round aluminum nitride powder with an average particle size of 20.9 μm (1.02% by mass of sieve residue on 200 mesh wire screen, 8.76% by mass of comb residue on 325 mesh wire screen) C-2-1: Round aluminum nitride powder with an average particle size of 6.6 μm (0.01% by mass of sieve residue on 200 mesh wire screen, 0.01% by mass of comb residue on 325 mesh wire screen) C-2-2: Round aluminum nitride powder with an average particle size of 2.6 μm (0.01% by mass of sieve residue on 200 mesh wire screen, 0.01% by mass of comb residue on 325 mesh wire screen) C-2-3: Spherical aluminum oxide powder with an average particle size of 3.6 μm (0.01% by mass on sieve through 200 mesh wire screen, 0.01% by mass on comb through 325 mesh wire screen) C-3-1: Zinc oxide powder with an average particle size of 0.4 μm C-3-2: Zinc oxide powder with an average particle size of 0.9 μm C-3-3: Aluminum nitride powder with average particle size of 0.7 μm C-3-4: Aluminum oxide powder with average particle size of 0.9 μm [(D) component] D-1: Organohydrogenpolysiloxane represented by the following formula: [ka] D-2: Organohydrogenpolysiloxane represented by the following formula: [ka] d-3: Organohydrogenpolysiloxane represented by the following formula (comparison product) [ka] [(E) component] E-1: Organohydrogenpolysiloxane represented by the following formula: [ka] E-2: Organohydrogenpolysiloxane represented by the following formula: [ka] [Component (F)] F-1: Hydrolyzable organopolysiloxane represented by the following formula: [ka] F-2: Hydrolyzable organopolysiloxane represented by the following formula: [ka] [(G) component] G-1: A solution of platinum-divinyltetramethyldisiloxane complex dissolved in the same dimethylpolysiloxane as A-1 (platinum atom content: 1% by mass) [(H) component] H-1: A compound represented by the following formula: [ka]

[0060] [Examples 1 to 18, Comparative Examples 1 to 5] (1) Preparation of Silicone Composition Silicone compositions were prepared by blending the above components (A) to (H) in the amounts and by the method described below in Tables 1 to 3. In Table 1, the mass of component (G) is the mass of a solution (platinum atom content: 1% by mass) in which a platinum-divinyltetramethyldisiloxane complex is dissolved in dimethylpolysiloxane.

[0061] Components (A), (B), (C), and (F) were added to a 5-liter planetary mixer (Inoue Seisakusho Co., Ltd.) and mixed for 1 hour at 170° C. The mixture was cooled to room temperature, and then components (D), (E), (G), and (H) were added and mixed until uniform, preparing a silicone composition.

[0062] The viscosity, thermal conductivity, elongation at break and adhesive strength of each composition obtained above were measured according to the following methods. The results are shown in Tables 1 and 2.

[0063] [viscosity] The absolute viscosity of each composition was measured at 25° C. using a Malcolm viscometer (type PC-1T).

[0064] [Thermal Conductivity] Each composition was heated at 125° C. for 60 minutes to cure and prepared into a 6 mm thick sheet, and the thermal conductivity was measured using a Kyoto Electronics Manufacturing Co., Ltd. TPS-2500.

[0065] [Thickness measurement] Each composition was sandwiched between two circular aluminum plates (diameter 12.6 mm, thickness 1 mm) to a thickness of 100 μm, and a pressure of 0.1 MPa was applied at 25° C. for 60 minutes to prepare a test specimen. The thickness of the test piece was measured with a micrometer (manufactured by Mitutoyo Corp.), and the thickness of the composition was determined by subtracting the thickness of the aluminum plate, which had been measured beforehand.

[0066] [Measurement of tensile shear adhesive strength] Each composition was sandwiched between two 1.0 mm thick aluminum (JIS H 4000 A1050P) plates so that the thickness was 2.0 mm and the adhesive area was 25 mm × 10 mm, and heated at 125 ° C for 1 hour to cure the composition and prepare an adhesive test piece. The tensile shear adhesive strength of the obtained test piece was measured according to JIS K 6850.

[0067]

Table 1

[0068]

Table 2

[0069]

Table 3

[0070]

Table 4

[0071] From the results of Tables 1 to 4, in Examples 1 to 18, which satisfy the requirements of the present invention, the silicone composition had a low viscosity, a high thermal conductivity, and a strong adhesive strength, compared to Comparative Examples 1 to 5. On the other hand, Comparative Example 1, in which the amount of the (C) component was as low as 3,540 parts by mass relative to 100 parts by mass of the (A) component, had a low thermal conductivity. Comparative Example 2, in which the amount of the (B) component was as high as 650 parts by mass relative to 100 parts by mass of the (A) component, and Comparative Example 3, which did not contain the (F) component, had low adhesive strength. In Comparative Example 4, in which the amount of the (C) component was high, the composition was not uniform. In Comparative Example 5, in which the (D) component had a ratio of n / (n+m)>0.5, the composition did not cure. In Comparative Example 6, in which the (E) component was not contained, the adhesive strength was low.

[0072] Therefore, it was confirmed that the silicone composition of the present invention, when used to firmly bond a semiconductor chip to a heat spreader, exhibits good adhesive properties even when it contains a large amount of thermally conductive filler.

Claims

1. A silicone composition comprising the following components (A) to (H): (A) A polymer having at least two aliphatic unsaturated hydrocarbon groups per molecule and a kinematic viscosity at 25°C of 60 to 100,000 mm 2 / s: 100 parts by mass of organopolysiloxane (B) 100 to 600 parts by mass of a hydrolyzable organopolysiloxane represented by the following general formula (1): 【Chemistry 1】 (In the formula, R 1 are each independently an alkyl group having 1 to 6 carbon atoms, and r is an integer of 5 to 100. (C) At least one thermally conductive filler selected from the group consisting of metal oxides and metal nitrides: 4,001 to 12,000 parts by mass (D) 1.0 to 8.0 parts by mass of an organohydrogenpolysiloxane represented by the following general formula (2): 【Chemistry 2】 (wherein n and m are each a number greater than 0, and satisfy the conditions 5.0≦n+m≦100 and n / (n+m)≦0.5; R 2 are each independently an alkyl group having 1 to 6 carbon atoms. (E) Organohydrogenpolysiloxane represented by the following general formula (3): 1.0 to 7.0 parts by mass 【Transformation 3】 (wherein o is an integer of 1 to 8, R 3 are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or R 4 where R 3 Two or three of the groups represented by the formula (I) are hydrogen atoms. 4 is a group bonded to a silicon atom via a carbon atom or an oxygen atom and selected from the group consisting of an epoxy group, an acryloyl group, a methacryloyl group, an ether group, and a trialkoxysilyl group. (F) Hydrolyzable organopolysiloxane represented by the following general formula (4): 1 to 30 parts by mass 【Chemistry 4】 (wherein p and q are each a number equal to or greater than 1.0 and satisfy the relationship 5.0≦p+q≦100; R 5 are each independently an alkyl group having 1 to 6 carbon atoms, and R 6 is an alkenyl group having 2 to 6 carbon atoms. (G) Platinum group metal catalyst: effective amount (H) Reaction inhibitor: 0.05 to 5.0 parts by mass

2. 2. The silicone composition according to claim 1, wherein component (C) comprises the following components (C-1) to (C-3): (C-1) Aluminum nitride particles having an average particle size of 10 μm or more but less than 30 μm, and a residue when sieved through a 200-mesh wire screen of less than 1.0 mass % (C-2) Metal oxide or metal nitride with an average particle size of 1 μm or more and less than 10 μm (C-3) Metal oxide or metal nitride with an average particle size of 0.1 μm or more and less than 1 μm

3. 2. The silicone composition according to claim 1, wherein the cured product has a thermal conductivity of at least 4.0 W / m·K.

4. A semiconductor device in which a cured silicone composition is interposed between a heat-generating member and a cooling member, A semiconductor device, wherein the cured layer is made of the cured silicone composition according to any one of claims 1 to 3 and has a thickness of 100 µm or less.

5. A method for producing the silicone composition according to claim 2, comprising: A method for producing a silicone composition, comprising the step of previously mixing components (C-1) to (C-3) with component (A) and component (B).

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