JP2010150399A - Thermally conductive silicone grease composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flexible thermally conductive silicone grease composition which can respond to a large warp of the IC package. <P>SOLUTION: The thermally conductive silicone grease composition includes (A) alkenyl group-containing organopolysiloxane, (B) organohydrogenpolysiloxane having an SiH group in a side chain, (C) organohydrogenpolysiloxane having an SiH group in both ends, (D) a thermally conductive filler, (E) a catalyst selected from the group consisting of platinum and platinum compounds, (F) a control agent, and (G) organopolysiloxane expressed by R<SP>3</SP><SB>a</SB>SiO<SB>(4-a)/2</SB>(wherein, R<SP>3</SP>is a monovalent hydrocarbon group and a is 1.8-2.2), wherein the amount of blend of (B) and (C) is such that äthe total number of SiH groups in (B) and (C)}/äthe number of alkenyl group in (A)} is 0.6-1.5, and the ratio of (B) to (C) is such that äthe number of SiH's derived from (C)}/äthe number of SiH's derived from (B)} is 1.0-10.0. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a thermally conductive silicone grease composition that can not only follow an IC package having a particularly large warp, but also does not easily cause a pumping out phenomenon.

  Currently, not only in the semiconductor industry, but also in various fields such as the automobile industry and home appliance manufacturers, the introduction of semiconductor devices has begun regardless of the field. The structure of a semiconductor device which is currently mainstream is composed of an IC package and a heat radiating body for releasing heat from the surface of the IC package. And in the meantime, the heat conductive silicone composition is poured and thermoset in a state where pressure is applied, and the heating element and the heat radiating body are buried while filling the unevenness on the surface of the IC package and the heat radiating body that exist microscopically. They are connected (Japanese Patent Laid-Open No. 2002-327116: Patent Document 1). At this time, it is also possible to use a heat radiating sheet or heat radiating grease. However, when a heat dissipation sheet is used, the microscopic unevenness cannot be completely filled, and as a result, air having a large heat insulating effect is sandwiched together, resulting in an IC that generates a large amount of heat. The package cannot provide a sufficient heat dissipation effect. In addition, there is an adhesive layer provided on the surface of the heat dissipation sheet so that air does not enter, but this is also insufficient for the same reason when used in an IC package with a large amount of heat generation. It can be said. In order to completely eliminate such air, liquid heat dissipation grease is suitable, but unlike the above heat conductive silicone composition, this heat dissipation grease cannot be cured after mounting. When used for a long time, there is a disadvantage that silicone oil as a component oozes out, or in the worst case, the heat radiating grease itself escapes from between the IC package and the heat radiating body. In order to avoid such a problem, there is a method in which a liquid silicone composition is connected to a heat generator and a heat radiator using a potting agent or an adhesive (JP-A-61-157569, JP-A-8). -208993 gazette: Patent Documents 2 and 3), this method also has some problems. It is difficult to increase the filler content for imparting thermal conductivity, resulting in insufficient thermal conductivity as a composition, and flexibility due to heat received from the heating element after curing and moisture from the outside. For example, it is lost and peeling occurs over time. Currently, the mainstream method for solving all of the above-mentioned problems is to cure the liquid heat conductive silicone composition after pouring between the heat generator and the heat radiator.

  However, in recent years, the structure of IC packages has changed, and existing thermal conductive silicone compositions have become unable to cope with them. For example, the total area of the CPU is increasing, and the organic substrate to which the CPU is attached is becoming thinner. That is, when such a structural change occurs, warpage at the time of heating and at room temperature becomes larger than ever. As a result, in an extreme case, peeling occurs at the interface between the heat conductive silicone composition and the heat spreader or the interface with the CPU, and it becomes impossible to follow. As a result, the heat conductive silicone composition does not peel off from the interface. It causes cohesive failure. In order to solve such a problem, conventionally, in order to improve the followability, the amount of the filler or the amount of the crosslinking material has been reduced in order to soften the thermally conductive silicone composition. However, in the former method, heat dissipation performance is sacrificed, and in the latter method, as a result of being softened, the heat dissipation grease approaches that amount, so that it escapes from between the IC package and the heat dissipation body. An out phenomenon occurs, which is not a fundamental solution. Accordingly, there has been a strong demand for the development of a thermally conductive silicone composition that can follow warpage while maintaining the properties of maintaining heat dissipation performance and preventing pumping out.

JP 2002-327116 A JP-A 61-157469 Japanese Patent Application Laid-Open No. 8-208993

  The present invention is a characteristic that does not cause a pumping out phenomenon without lowering the heat radiation performance as usual even after the liquid heat conductive silicone grease composition is poured between the heat generator and the heat radiator and then cured. It is an object to provide a flexible thermally conductive silicone grease composition that can follow a large warp of an IC package while maintaining the above.

  As a result of intensive studies to achieve the above object, the present inventors have found that a soft material can be provided without lowering reliability by adding the following component (G) as a plasticizer. Invented the invention.

（式中、Ｒ¹は互いに同一又は異種の炭素数１〜６のアルキル基、ｎ、ｍは正数で、０．０１≦ｎ／（ｎ＋ｍ）≦０．３を満足する。）
で示されるオルガノハイドロジェンポリシロキサン、
成分（Ｃ）：
下記一般式（２）

（式中、Ｒ²は互いに同一又は異種の炭素数１〜６のアルキル基、ｐは５〜１，０００の範囲の正数である。）
で示されるオルガノハイドロジェンポリシロキサン、
成分（Ｄ）：
１０Ｗ／ｍ℃以上の熱伝導率を有する熱伝導性充填剤 ８００〜２，０００質量部、
成分（Ｅ）：
白金及び白金化合物からなる群より選択される触媒
白金原子として成分（Ａ）の０．１〜５００ｐｐｍとなる配合量、
成分（Ｆ）：
アセチレン化合物、窒素化合物、有機りん化合物、オキシム化合物、有機クロロ化合物より選択される制御剤 ０．０１〜１質量部、
成分（Ｇ）：
下記平均組成式（３）
Ｒ³ _aＳｉＯ_(4-a)/2 （３）
（式中、Ｒ³は独立に非置換又は置換の炭素数１〜１８の一価炭化水素基であり、ａは１．８〜２．２の数である。）
で表される２５℃における動粘度が１０〜１００，０００ｍｍ²／ｓのオルガノポリシロキサン ０．１〜１００質量部
を含有し、上記成分（Ｂ）と成分（Ｃ）の配合量は｛成分（Ｂ）と成分（Ｃ）を合わせたＳｉ−Ｈ基の個数｝／｛成分（Ａ）のアルケニル基の個数｝が０．６〜１．５になる配合量であり、更には成分（Ｂ）と成分（Ｃ）の割合は、
｛成分（Ｃ）由来のＳｉ−Ｈの個数｝／｛成分（Ｂ）由来のＳｉ−Ｈの個数｝が１．０〜１０．０になる割合であり、２５℃の粘度が５０〜１，０００Ｐａ・ｓであることを特徴とする熱伝導性シリコーングリース組成物。
請求項２：
更に、成分（Ｈ）として、下記一般式（４）で表されるオルガノシラン及び／又は下記一般式（５）で表されるオルガノポリシロキサンを成分（Ａ）１００質量部に対し０．０１〜３０質量部含有することを特徴とする請求項１記載の熱伝導性シリコーングリース組成物。
Ｒ⁴ _bＲ⁵ _cＳｉ（ＯＲ⁶）_4-b-c （４）
（式中、Ｒ⁴は炭素数６〜１５のアルキル基、Ｒ⁵は炭素数１〜８の一価炭化水素基、Ｒ⁶は炭素数１〜６のアルキル基であり、ｂは１〜３の整数、ｃは０〜２の整数、ｂ＋ｃは１〜３の整数である。）

（式中、Ｒ⁷は独立に非置換又は置換の一価炭化水素基であり、Ｒ⁸は独立にアルキル基、アルコキシアルキル基、アルケニル基又はアシル基であり、ｑは５〜１００の整数、ｄは１〜３の整数である。）
請求項３：
沸点８０〜３６０℃の揮発性有機溶剤を成分（Ａ）１００質量部に対し０．１〜４０質量部含有することを特徴とする請求項１又は２記載の熱伝導性シリコーングリース組成物。 Accordingly, the present invention provides the following thermally conductive silicone grease composition.
Claim 1:
Ingredient (A):
100 parts by mass of an organopolysiloxane having a kinematic viscosity at 25 ° C. of 10 to 100,000 mm ² / s having at least two alkenyl groups in one molecule,
Ingredient (B):
The following general formula (1)

(Wherein R ¹ is the same or different alkyl group having 1 to 6 carbon atoms, n and m are positive numbers and satisfy 0.01 ≦ n / (n + m) ≦ 0.3).
An organohydrogenpolysiloxane represented by
Component (C):
The following general formula (2)

(In the formula, R ² is the same or different alkyl group having 1 to 6 carbon atoms, and p is a positive number in the range of 5 to 1,000.)
An organohydrogenpolysiloxane represented by
Component (D):
800 to 2,000 parts by mass of a thermally conductive filler having a thermal conductivity of 10 W / m ° C. or higher,
Ingredient (E):
Catalyst selected from the group consisting of platinum and platinum compounds
Compounding amount of 0.1 to 500 ppm of component (A) as platinum atom,
Ingredient (F):
0.01 to 1 part by mass of a control agent selected from an acetylene compound, a nitrogen compound, an organic phosphorus compound, an oxime compound, and an organic chloro compound,
Ingredient (G):
The following average composition formula (3)
R ³ _a SiO _{(4-a) / 2} (3)
(In the formula, R ³ is independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 18 carbon atoms, and a is a number of 1.8 to 2.2.)
Containing 0.1 to 100 parts by mass of an organopolysiloxane having a kinematic viscosity of 10 to 100,000 mm ² / s at 25 ° C., and the blending amount of the component (B) and the component (C) is {component ( B) and the number of Si-H groups combined with component (C) / {the number of alkenyl groups of component (A)} is 0.6 to 1.5, and further the component (B) And the ratio of component (C) is
{Number of Si—H derived from component (C)} / {Number of Si—H derived from component (B)} is a ratio of 1.0 to 10.0, and a viscosity at 25 ° C. is 50 to 1, 000 Pa · s, a thermally conductive silicone grease composition.
Claim 2:
Furthermore, as the component (H), an organosilane represented by the following general formula (4) and / or an organopolysiloxane represented by the following general formula (5) is added in an amount of 0.01 to 100 parts by mass with respect to 100 parts by mass of the component (A). The heat conductive silicone grease composition according to claim 1, comprising 30 parts by mass.
R ⁴ _b R ⁵ _c Si (OR ⁶ ) _4-bc (4)
Wherein R ⁴ is an alkyl group having 6 to 15 carbon atoms, R ⁵ is a monovalent hydrocarbon group having 1 to 8 carbon atoms, R ⁶ is an alkyl group having 1 to ⁶ carbon atoms, and b is 1 to 3 C is an integer of 0 to 2, and b + c is an integer of 1 to 3.)

Wherein R ⁷ is independently an unsubstituted or substituted monovalent hydrocarbon group, R ⁸ is independently an alkyl group, an alkoxyalkyl group, an alkenyl group or an acyl group, q is an integer of 5 to 100, d is an integer of 1 to 3)
Claim 3:
The thermally conductive silicone grease composition according to claim 1 or 2, which contains 0.1 to 40 parts by mass of a volatile organic solvent having a boiling point of 80 to 360 ° C with respect to 100 parts by mass of the component (A).

  According to the present invention, it is possible to provide a thermally conductive silicone grease composition that can follow even an IC package that warps much more than existing ones and has high reliability.

The organopolysiloxane of component (A) constituting the present invention has at least two alkenyl groups directly bonded to silicon atoms in one molecule, and may be linear or branched, and these two or more types are different. It may be a mixture of viscosities. Examples of the alkenyl group include a vinyl group, an allyl group, a 1-butenyl group, and a 1-hexenyl group, but a vinyl group is preferable from the viewpoint of ease of synthesis and cost. The remaining organic group bonded to the silicon atom has no aliphatic unsaturated bond, such as an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, and a dodecyl group, and a phenyl group. Examples include aralkyl groups such as an aryl group, 2-phenylethyl group, and 2-phenylpropyl group, and halogen-substituted hydrocarbon groups such as chloromethyl group and 3,3,3-trifluoropropyl group. Of these, 90 mol% or more of all organic groups bonded to the silicon atom are preferably methyl groups from the viewpoint of ease of synthesis and cost. The alkenyl group bonded to the silicon atom may be present at either the end or in the middle of the molecular chain of the organopolysiloxane, but in terms of flexibility, it is preferably present only at both ends. 25 to the storage stability of viscosity at ℃ is lower than 10 mm ² / s composition is deteriorated, 100,000 mm ² / s from increases because the extensibility of the composition is deteriorated obtained, 10~100,000mm ² / S, preferably 100 to 50,000 mm ² / s. The viscosity is a value measured with an Ostwald viscometer.

（但し、ｎとｍが０．０１≦ｎ／（ｎ＋ｍ）≦０．３（ｎ、ｍは正数）の範囲にあり、Ｒ¹は炭素数１〜６のアルキル基である。） The component (B) is an organohydrogenpolysiloxane represented by the following general formula (1).

(However, n and m are in the range of 0.01 ≦ n / (n + m) ≦ 0.3 (n and m are positive numbers), and R ¹ is an alkyl group having 1 to 6 carbon atoms.)

  In the organohydrogenpolysiloxane represented by the formula (1) of the component (B), if n and m are positive numbers and n / (n + m) is less than 0.01, the composition cannot be reticulated by crosslinking, and If it is greater than 3, the amount of unreacted Si-H groups remaining after the initial curing increases, and excessive crosslinking reaction proceeds with time due to moisture and the like, so that the flexibility of the composition is lost. The range is preferably 0.05 to 0.2.

R ¹ is an alkyl group selected from a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, etc., and among these, 90 mol% or more of R ¹ is more preferable from the viewpoint of ease of synthesis and cost. A methyl group is preferred.

（但し、ｐは正数で、５〜１，０００の範囲であり、Ｒ²は炭素数１〜６のアルキル基である。） Component (C) is an organohydrogenpolysiloxane represented by the following general formula (2).

(However, p is a positive number in the range of 5 to 1,000, and R ² is an alkyl group having 1 to 6 carbon atoms.)

  When the p of the organohydrogenpolysiloxane represented by the formula (2) of the component (C) is less than 5, it tends to be a volatile component and is not preferred for use in electronic parts. Is difficult, the range is 5 to 1,000, preferably 10 to 100.

R ² is an alkyl group selected from a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, and the like, and among these, 90 mol% or more of R ² is present from the viewpoint of ease of synthesis and cost. A methyl group is preferred.

  The blending amount of component (B) and component (C) is the number of Si—H groups in component (B) and component (C) relative to the number of alkenyl groups in component (A), ie {component If the number of Si-H groups in which (B) and component (C) are combined} / {number of alkenyl groups in component (A)} is less than 0.6, a sufficient network structure cannot be obtained, and the necessary hardness after curing. If the ratio is greater than 1.5, the unreacted Si-H group undergoes an excessive crosslinking reaction due to moisture or the like and becomes hard, and the flexibility of the composition is lost. The range is good. Preferably it is 0.7-1.4.

  The ratio of component (B) to component (C) is such that {number of Si-H derived from component (C)} / {number of Si-H derived from component (B)} is less than 1.0. When appropriate flexibility afterward is not obtained and curing is insufficient when it is greater than 10.0, the range is 1.0 to 10.0, preferably 1.5 to 5.0.

  The filler of component (D) is for imparting thermal conductivity to the present invention. In the filler of the present invention, if the thermal conductivity of the filler is less than 10 W / m ° C., the thermal conductivity of the silicone grease composition for heat dissipation itself becomes small, so the thermal conductivity of the filler is 10 W / m. It is above ℃. Thermal conductive fillers include aluminum powder, copper powder, silver powder, nickel powder, gold powder, alumina powder, zinc oxide powder, magnesium oxide powder, aluminum nitride powder, boron nitride powder, silicon nitride powder, diamond powder, carbon Examples thereof include powder, indium, and gallium. Any filler may be used as long as the thermal conductivity is 10 W / m ° C. or more, and one or two or more may be mixed.

  When the amount of the thermally conductive filler (D) is less than 800 parts by mass with respect to 100 parts by mass of the component (A), the desired thermal conductivity cannot be obtained, and when it is greater than 2,000 parts by mass, it becomes a grease. However, since it becomes poor in extensibility, it is in the range of 800 to 2,000 parts by mass, preferably in the range of 1,000 to 1,900 parts by mass.

If the average particle size of the thermally conductive filler is less than 0.1 μm, it may not be in the form of grease and may have poor extensibility, and if it is greater than 100 μm, the uniformity of the heat dissipating grease may be poor. A range of 0.1 to 100 μm is preferable. The shape of the filler may be indefinite, spherical or any shape. The average particle diameter can be measured as a volume average value D ₅₀ (that is, a particle diameter or a median diameter when the cumulative volume is 50%) in particle size distribution measurement by a laser light diffraction method.

  The catalyst selected from platinum of component (E) and a platinum compound is a component for promoting the addition reaction between the alkenyl group of component (A) and the Si—H group of component (B) and component (C). Examples of this component (E) include platinum alone, chloroplatinic acid, platinum-olefin complexes, platinum-alcohol complexes, and platinum coordination compounds.

  Since the compounding amount of the component (E) is less than 0.1 ppm as a platinum atom with respect to the mass of the component (A), there is no effect as a catalyst. It is in the range of 0.1 to 500 ppm.

  The control agent of component (F) suppresses the progress of the hydrosilylation reaction at room temperature and extends shelf life and pot life. Known reaction control agents can be used, and acetylene compounds, various nitrogen compounds, organic phosphorus compounds, oxime compounds, organic chloro compounds, and the like can be used.

  If the blending amount of component (F) is less than 0.01 parts by mass with respect to 100 parts by mass of component (A), sufficient shelf life and pot life cannot be obtained, and if it is greater than 1 part by mass, curability decreases. Therefore, it is the range of 0.01-1 mass part. These can be used after being diluted with an organic solvent such as toluene, xylene, isopropyl alcohol or the like in order to improve dispersibility in the silicone resin.

The plasticizer of component (G) has the following average composition formula (3)
R ³ _a SiO _{(4-a) / 2} (3)
(In the formula, R ³ is independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 18 carbon atoms, and a is a positive number of 1.8 to 2.2.)
Is an organopolysiloxane having a kinematic viscosity at 25 ° C. of 10 to 100,000 mm ² / s. If the kinematic viscosity is less than 10 mm ² / s, it becomes easy to come out of the composition after curing, the softness cannot be maintained, the followability cannot be maintained, and it exceeds 100,000 mm ² / s. The viscosity of the composition itself is increased and the dischargeability is deteriorated, so the kinematic viscosity at 25 ° C. is 10 to 100,000 mm ² / s, more preferably 50 to 10,000 mm ² / s. Organopolysiloxane is preferred.

  The compounding quantity of a component (G) is 0.1-100 mass parts with respect to 100 mass parts of components (A), Preferably it is 0.5-90 mass parts, More preferably, it is 1.0-80 mass parts. If the blending amount is too small, it will not be possible to follow the large warp of the IC package, and if the blending amount is too large, a pumping out phenomenon will occur.

（式中、Ｒ⁷は独立に非置換又は置換の一価炭化水素基であり、Ｒ⁸は独立にアルキル基、アルコキシアルキル基、アルケニル基又はアシル基であり、ｑは５〜１００の整数、ｄは１〜３の整数である。） In the present invention, in addition to the components (A) to (G), it is effective to use an additive for improving the wettability of the filler and the silicone component as the component (H) as necessary. Any additive that can improve wettability may be used, but organosilanes represented by the following general formula (4) and organopolysiloxanes represented by the following general formula (5) are particularly useful.
Organosilane represented by the general formula (4):
R ⁴ _b R ⁵ _c Si (OR ⁶ ) _4-bc (4)
Wherein R ⁴ is an alkyl group having 6 to 15 carbon atoms, R ⁵ is a monovalent hydrocarbon group having 1 to 8 carbon atoms, R ⁶ is an alkyl group having 1 to ⁶ carbon atoms, and b is 1 to 3 C is an integer of 0 to 2, and b + c is an integer of 1 to 3.)
Organopolysiloxane represented by the general formula (5):

(Wherein, R ⁷ is an unsubstituted or substituted monovalent hydrocarbon group independently, R ⁸ is independently an alkyl group, an alkoxyalkyl group, an alkenyl group or an acyl group, q is 5 to 100 integer, d is an integer of 1 to 3)

Here, specific examples of R ⁴ include, for example, hexyl group, octyl group, nonyl group, decyl group, dodecyl group, tetradecyl group and the like. If the carbon number is less than 6, the wettability with the filler is not sufficient, and if it is more than 15, the organosilane is solidified at room temperature, which is inconvenient to handle and the low temperature characteristics of the resulting composition are lowered. B is 1, 2 or 3, but 1 is particularly preferable. R ⁵ is a saturated or unsaturated monovalent hydrocarbon group having 1 to 8 carbon atoms, particularly 1 to 6 carbon atoms. Examples of such groups include alkyl groups, cycloalkyl groups, and alkenyl groups. . Specifically, alkyl groups such as methyl group, ethyl group, propyl group, hexyl group, octyl group, cycloalkyl groups such as cyclopentyl group, cyclohexyl group, alkenyl groups such as vinyl group, allyl group, phenyl group, tolyl group, etc. Aryl groups, aralkyl groups such as 2-phenylethyl group, 2-methyl-2-phenylethyl group, 3,3,3-trifluoropropyl group, 2- (nanofluorobutyl) ethyl group, 2- (heptadeca Halogenated hydrocarbon groups such as fluorooctyl) ethyl group and p-chlorophenyl group are mentioned, and methyl group and ethyl group are particularly preferable. R ⁶ is one or more alkyl groups having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group, and a methyl group and an ethyl group are particularly preferable.

Specific examples of the organosilane represented by the general formula (4) include the following.
C ₆ H ₁₃ Si (OCH ₃ ) _3, C ₁₀ H ₂₁ Si (OCH ₃ ) ₃ , C ₁₂ H ₂₅ Si (OCH ₃ ) ₃ ,
C ₁₂ H ₂₅ Si (OC ₂ H ₅ ) ₃ , C ₁₀ H ₂₁ Si (CH ₃ ) (OCH ₃ ) ₂ ,
_{C 10 H 21 Si (C 6} H 5) (OCH 3) 2, C 10 H 21 Si (CH 3) (OC 2 H 5) 2,
C ₁₀ H ₂₁ Si (CH═CH ₂ ) (OCH ₃ ) ₂ ,
C ₁₀ H ₂₁ Si (CH ₂ CH ₂ CF ₃ ) (OCH ₃ ) ₂

On the other hand, in the organopolysiloxane used as the wettability improver, R ^{7 in the} general formula (5) is independently an unsubstituted or substituted monovalent hydrocarbon group, preferably having 1 to 18 carbon atoms. Examples thereof include linear alkyl groups, branched alkyl groups, cyclic alkyl groups, alkenyl groups, aryl groups, aralkyl groups, and halogenated alkyl groups. Examples of the linear alkyl group include a methyl group, an ethyl group, a propyl group, a hexyl group, and an octyl group. Examples of the branched alkyl group include isopropyl group, isobutyl group, tert-butyl group, 2-ethylhexyl group and the like. Examples of the cyclic alkyl group include a cyclopentyl group and a cyclohexyl group. Examples of the alkenyl group include a vinyl group and an allyl group. Examples of the aryl group include a phenyl group and a tolyl group. Examples of the aralkyl group include a 2-phenylethyl group and a 2-methyl-2-phenylethyl group. Examples of the halogenated alkyl group include 3,3,3-trifluoropropyl group, 2- (nonafluorobutyl) ethyl group, 2- (heptadecafluorooctyl) ethyl group, and the like. R ⁷ is preferably a methyl group or a phenyl group. R ⁸ is independently an alkyl group, an alkoxyalkyl group, an alkenyl group or an acyl group, and preferably has 1 to 5 carbon atoms. Examples of the alkyl group include the same linear alkyl group, branched alkyl group, and cyclic alkyl group as those exemplified for R ⁷ . Examples of the alkoxyalkyl group include a methoxyethyl group and a methoxypropyl group. Examples of the acyl group include an acetyl group and an octanoyl group. R ⁸ is preferably an alkyl group, particularly preferably a methyl group or an ethyl group. q is an integer of 5 to 100. d is an integer of 1 to 3, preferably 3.

  Specific examples of the organopolysiloxane represented by the general formula (5) include the following.

（Ｍｅはメチル基を示す。）

(Me represents a methyl group.)

  If the amount of component (H) is less than 0.01 parts by mass relative to 100 parts by mass of component (A), the wettability will be poor, and if it exceeds 30 parts by mass, the effect will increase. Since it is uneconomical, the range of 0.01 to 30 parts by mass is good, and more preferably 10 to 25 parts by mass.

  Further, an organic solvent having a boiling point of 80 to 360 ° C. in which the components (A) to (G) and the component (H) are dispersed or dissolved can be blended, and the solvent is not particularly limited. For example, toluene, xylene, Although isoparaffin etc. are mentioned, the isoparaffin-type solvent is preferable from the point of workability | operativity. It is effective that the isoparaffin has a boiling point of 80 to 360 ° C, more preferably 260 to 360 ° C, and still more preferably 260 to 300 ° C. In this case, if the boiling point of the isoparaffinic solvent is less than 80 ° C., the volatilization becomes too fast and the viscosity of the composition increases during the operation. On the other hand, if the boiling point exceeds 360 ° C., the solvent tends to remain in the silicone grease composition, and voids are generated, resulting in deterioration of thermal characteristics.

  It is preferable that the compounding quantity of the said solvent is 0.1-40 mass parts with respect to 100 mass parts of components (A), More preferably, it is 10-30 mass parts. If the blending amount is less than 0.1 parts by mass, the viscosity of the silicone grease composition may not be sufficiently lowered, and if it exceeds 40 parts by mass, it may be difficult to cure.

  By the way, the thermal conductivity of the silicone grease composition for heat dissipation basically has a correlation with the blending amount of the thermally conductive filler, and the thermal conductivity improves as the blending amount of the thermally conductive filler increases. On the other hand, since the viscosity of the heat-dissipating silicone grease composition itself increases when the amount of the thermally conductive filler is large, there is an upper limit to the amount of the thermally conductive filler in consideration of workability and handling properties. is there. Therefore, by blending a small amount of solvent component, the viscosity of the heat-dissipating silicone grease composition is drastically reduced, and workability and handling are ensured even if the amount of the thermally conductive filler is larger than that of the conventional composition. be able to.

  In addition to the components (A) to (G) described above, the present invention includes an organosilane of the general formula (4), an organopolysiloxane of the general formula (5), and a volatile solvent. If necessary, an adhesion aid or the like may be added to chemically bond and fix an IC package such as a CPU and a heat sink such as a heat sink, or an antioxidant or the like may be added to prevent deterioration. Good.

  The thermally conductive silicone composition of the present invention can be stored at a low temperature for a long period of time as a one-component addition type by mixing the above components (A) to (G), further the component (H) and other optional components. Moreover, what added the volatile solvent to these can also be stored at low temperature for a long time as a 1 liquid addition type.

  In the present invention, at the time of assembling a semiconductor device, the thermally conductive silicone composition is packed in a commercially available syringe and applied and bonded onto the surface of an IC package such as a CPU. For this reason, if the viscosity is lower than 50 Pa · s, dripping occurs at the time of coating, and if it is higher than 1,000 Pa · s, the coating efficiency is deteriorated, so that it can be used in the range of 50 to 1,000 Pa · s. However, 100 to 400 Pa · s is preferable. This viscosity is a value measured with a Malcolm viscometer.

  After being dispensed, it is cured by the heat generated from the IC package, and after curing, this composition has tackiness, so it may deviate from the base material and may peel off from the base material because of its stable flexibility over time. Never do. In addition, after dispensing, heat curing may be performed positively, and the curing condition is preferably heating at 120 ° C. for 90 minutes.

  In addition, a manufacturing method takes a component (A), (B), (C), (D), (G) to a gate mixer (The product name: Planetary mixer by Inoue Seisakusho Co., Ltd.), and as needed. Add component (H), organosilane or organopolysiloxane, mix for 1 hour at room temperature, then add component (F), for example, mix for 15 minutes at room temperature, then add component (E), and add For example, a method of mixing at room temperature for 15 minutes can be employed, but is not limited thereto.

EXAMPLES Hereinafter, although an Example is hung up and this invention is further explained in full detail, this invention is not limited to the following Example.
First, the following components for forming the composition of the present invention were prepared. In the following examples, Me represents a methyl group.

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

Ingredient (B):
Organohydrogenpolysiloxane represented by the following formula

Component (C):
Organohydrogenpolysiloxane represented by the following formula

Component (D):
The following aluminum powder, alumina powder and zinc oxide powder were mixed at room temperature for 15 minutes at a mixing ratio shown in Table 1 below using a 5-liter gate mixer (trade name: 5-liter planetary mixer manufactured by Inoue Seisakusho Co., Ltd.). , D-1 to 3 were obtained.
Aluminum powder with an average particle size of 4.9 μm Aluminum powder with an average particle size of 15.0 μm Alumina powder with an average particle size of 15.0 μm Zinc oxide powder with an average particle size of 1.0 μm

Ingredient (E):
E-1
A-1 solution of platinum-divinyltetramethyldisiloxane complex, containing 1% by mass as platinum atoms

Ingredient (F):
F-1
50% by weight toluene solution of 1-ethynyl-1-cyclohexanol

Ingredient (G):
G-1
Dimethylorganopolysiloxane G-2 with a kinematic viscosity of 500 mm ² / s (for comparison)
Dimethylorganopolysiloxane G-3 with kinematic viscosity 5 mm ² / s (for comparison)
Dimethylorganopolysiloxane with kinematic viscosity 1,000,000 mm ² / s

Ingredient (H):
(Organosilane used)
H-1
Organosilane <1>: C ₆ H ₁₃ Si (OCH ₃ ) ₃
H-2
Organosilane <2>: C ₁₀ H ₂₁ Si (OCH ₃ ) ₃
(Used organopolysiloxane)
H-3
Organopolysiloxane <1>

(Solvent used)
IP Solvent 2835 (Isoparaffinic solvent, Idemitsu Kosan Co., Ltd., trade name) Boiling point 270-350 ° C

The said component was mixed as follows and the composition of Examples 1-9 and Comparative Examples 1-11 was obtained.
That is, the components (A), (B), (C), (G) and the solvent were taken in a 5 liter gate mixer (trade name: 5 liter planetary mixer manufactured by Inoue Seisakusho Co., Ltd.), and Tables 2 and 3 The component (D) was further weighed out at the blending amount shown, and organosilane or organopolysiloxane was added as the component (H) as necessary, and mixed at room temperature for 1 hour. Next, component (F) was added in the blending amounts shown in Tables 2 and 3, respectively, and mixed for 15 minutes at room temperature. Thereafter, the component (E) was further added in the amounts shown in Tables 2 and 3, respectively, and mixed for 15 minutes at room temperature so as to be uniform.

Thermal conductivity:
A test piece was prepared by sandwiching the compositions obtained in the above Examples and Comparative Examples between two aluminum plates having a diameter of 12.5 mm and a thickness of 1.0 mm, and the thickness of the test piece was measured with a micrometer (manufactured by Mitutoyo Corporation). The thickness of the composition was calculated by subtracting the thickness of two aluminum plates measured in advance. Several samples each having a different specimen thickness were prepared by such a method. Thereafter, each sample was allowed to stand at 125 ° C. for 90 minutes to be cured, and after waiting to cool well, the thickness of the composition was calculated again. Using the above test piece, the thermal resistance (unit: mm ² -K / W) of the composition was measured at 25 ° C. with a thermal resistance measuring instrument (manufactured by Netch, Xenon Flash Analyzer; LFA447 NanoFlash) based on the laser flash method. . The thermal resistance values with different thicknesses were plotted for each composition, and the thermal conductivity was calculated from the reciprocal of the slope of the straight line obtained therefrom.

viscosity:
The absolute viscosity of the composition showed a value at 25 ° C., and a Malcolm viscometer (type PC-1T) was used for the measurement.

Hardness measurement (use of Asker C manufactured by Kobunshi Keiki Co., Ltd. (for low hardness)):
The flexibility of the composition over time was evaluated by measuring the hardness. Poured into a 10 mm thick mold and heated at 125 ° C. for 1 hour to prepare a sheet-like rubber molded product having a thickness of 10 mm. Then, it returned to 25 degreeC and measured initial hardness. Further, after standing for 100 hours under conditions of a temperature of 130 ° C., a humidity of 100%, and 2 atmospheres, the temperature was returned to 25 ° C. and the hardness was measured again.

Reliability assessment:
The thermally conductive silicone grease composition was sandwiched between a silicon wafer (2 cm × 2 cm) and glass, and then allowed to cure at 125 ° C. for 90 minutes. Then, it was allowed to stand under heat cycle conditions [1,000 cycles of −45 ° C. (30 minutes) to 125 ° C. (30 minutes)] to check whether pumping out occurred. The case where the pumping out did not occur was defined as reliability ○, and the case where the pumping out occurred was defined as x.

Claims (3)

Ingredient (A):
100 parts by mass of an organopolysiloxane having a kinematic viscosity at 25 ° C. of 10 to 100,000 mm ² / s having at least two alkenyl groups in one molecule,
Ingredient (B):
The following general formula (1)

(Wherein R ¹ is the same or different alkyl group having 1 to 6 carbon atoms, n and m are positive numbers and satisfy 0.01 ≦ n / (n + m) ≦ 0.3).
An organohydrogenpolysiloxane represented by
Component (C):
The following general formula (2)

(In the formula, R ² is the same or different alkyl group having 1 to 6 carbon atoms, and p is a positive number in the range of 5 to 1,000.)
An organohydrogenpolysiloxane represented by
Component (D):
800 to 2,000 parts by mass of a thermally conductive filler having a thermal conductivity of 10 W / m ° C. or higher,
Ingredient (E):
Catalyst selected from the group consisting of platinum and platinum compounds
Compounding amount of 0.1 to 500 ppm of component (A) as platinum atom,
Ingredient (F):
0.01 to 1 part by mass of a control agent selected from an acetylene compound, a nitrogen compound, an organic phosphorus compound, an oxime compound, and an organic chloro compound,
Ingredient (G):
The following average composition formula (3)
R ³ _a SiO _{(4-a) / 2} (3)
(In the formula, R ³ is independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 18 carbon atoms, and a is a number of 1.8 to 2.2.)
Containing 0.1 to 100 parts by mass of an organopolysiloxane having a kinematic viscosity of 10 to 100,000 mm ² / s at 25 ° C., and the blending amount of the component (B) and the component (C) is {component ( B) and the number of Si-H groups combined with component (C) / {the number of alkenyl groups of component (A)} is 0.6 to 1.5, and further the component (B) And the ratio of component (C) is
{Number of Si—H derived from component (C)} / {Number of Si—H derived from component (B)} is a ratio of 1.0 to 10.0, and a viscosity at 25 ° C. is 50 to 1, 000 Pa · s, a thermally conductive silicone grease composition. Furthermore, as the component (H), an organosilane represented by the following general formula (4) and / or an organopolysiloxane represented by the following general formula (5) is added in an amount of 0.01 to 100 parts by mass with respect to 100 parts by mass of the component (A). The heat conductive silicone grease composition according to claim 1, comprising 30 parts by mass.
R ⁴ _b R ⁵ _c Si (OR ⁶ ) _4-bc (4)
Wherein R ⁴ is an alkyl group having 6 to 15 carbon atoms, R ⁵ is a monovalent hydrocarbon group having 1 to 8 carbon atoms, R ⁶ is an alkyl group having 1 to ⁶ carbon atoms, and b is 1 to 3 C is an integer of 0 to 2, and b + c is an integer of 1 to 3.)

Wherein R ⁷ is independently an unsubstituted or substituted monovalent hydrocarbon group, R ⁸ is independently an alkyl group, an alkoxyalkyl group, an alkenyl group or an acyl group, q is an integer of 5 to 100, d is an integer of 1 to 3)   The thermally conductive silicone grease composition according to claim 1 or 2, which contains 0.1 to 40 parts by mass of a volatile organic solvent having a boiling point of 80 to 360 ° C with respect to 100 parts by mass of the component (A).