JP4656340B2 - Thermally conductive silicone grease composition - Google Patents

Description

  The present invention relates to a thermally conductive silicone grease composition containing a volatile solvent.

  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 on the surface of the heat-dissipating sheet that has been devised to prevent air from entering, but this is also insufficient for the same reason when used in an IC package with a large amount of heat generation. I can say that.

  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. Loss and peeling off 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, even with the high thermal conductivity of this thermally conductive silicone composition, the situation is still insufficient. This is based on the background that the performance of IC chips in semiconductor devices must be further evolved to meet the demands of the times. In other words, this means that as the performance of an IC chip improves, the amount of heat generation becomes very large. Therefore, as a matter of course, if the heat generated from the IC package is increased more than before and is not released more efficiently, the performance and destruction of the IC package will be caused. In order to prevent such a situation, it has become increasingly important to further increase the thermal conductivity of the material connecting the heating element and the radiator.

  One of the methods to increase the thermal conductivity is to increase the filling rate of the thermal conductive filler, but even if this method is simply applied, the viscosity of the silicone composition will increase rapidly. As a result, there arises a problem that the dispensing property is rapidly deteriorated. Accordingly, there has been a strong demand for the development of a thermosetting thermally conductive silicone grease composition that improves the thermal conductivity while maintaining good dispensing properties.

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

  The present invention has been made in view of the above circumstances, and further develops a method of curing a liquid heat conductive silicone grease composition after pouring between a heat generating body and a heat radiating body, while improving the heat conductivity. Another object of the present invention is to provide a thermally conductive silicone grease composition that maintains dispensing performance.

As a result of intensive studies to achieve the above object, the present inventors have increased the filling amount of the filler more than ever by using a small amount of a volatile solvent, and the thermal conductivity of the composition. It was also found that the viscosity of the thermally conductive silicone grease composition can be kept low, and the present invention has been made.
The thermally conductive silicone grease composition of the present invention has the characteristics that it has high thermal conductivity and high discharge performance, is soft after curing, and can maintain its softness even after a long-term environmental test.

（式中、Ｒ¹は独立に炭素数１〜６のアルキル基である。ｎ，ｍは０．０１≦ｎ／（ｎ＋ｍ）≦０．３を満足する正数である。）
で示されるオルガノハイドロジェンポリシロキサン、
（Ｃ）下記一般式（２）

（式中、Ｒ²は独立に炭素数１〜６のアルキル基である。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（Ｂ）と成分（Ｃ）の合わせたＳｉ−Ｈ基の個数｝／｛成分（Ａ）のアルケニ
ル基の個数｝が０．６〜１．５の範囲であり、かつ｛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の範囲となる量、
（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、
（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、
（Ｆ）アセチレン化合物、窒素化合物、有機りん化合物、オキシム化合物及び有機クロロ化合物より選択される制御剤： ０．０１〜１質量部、
（Ｇ）前記成分（Ａ）〜（Ｆ）を分散又は溶解できる沸点が２７０〜３５０℃のイソパラフィン系溶剤： ０．１〜４０．０質量部
を含有してなり、２５℃の粘度が５０〜１，０００Ｐａ・ｓである熱伝導性シリコーングリース組成物。
〔２〕 更に、下記一般式（３）
Ｒ³ _aＲ⁴ _bＳｉ（ＯＲ⁵）_4-a-b （３）
（式中、Ｒ³は炭素数６〜１５のアルキル基、Ｒ⁴は炭素数１〜８の１価炭化水素基、Ｒ⁵は独立に炭素数１〜６のアルキル基であり、ａは１〜３の整数、ｂは０〜２の整数、かつａ＋ｂは１〜３の整数である。）
で示されるオルガノシランを（Ａ）成分１００質量部に対して０．０１〜３０．０質量部含む〔１〕記載の熱伝導性シリコーングリース組成物。
〔３〕 更に、下記一般式（４）

（式中、Ｒ⁶は独立に非置換又は置換の１価炭化水素基であり、Ｒ⁷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の整数であり、ｃは１〜３の整数である。）
で示されるオルガノポリシロキサンを（Ａ）成分１００質量部に対して０．０１〜３０．０質量部含む〔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.
[1] (A) Organopolysiloxane having at least two alkenyl groups in one molecule and a kinematic viscosity at 25 ° C. of 10 to 100,000 mm ² / s: 100 parts by mass
(B) The following general formula (1)

(In the formula, R ¹ is independently an alkyl group having 1 to 6 carbon atoms. N and m are positive numbers satisfying 0.01 ≦ n / (n + m) ≦ 0.3.)
An organohydrogenpolysiloxane represented by
(C) The following general formula (2)

(In the formula, R ² is independently an alkyl group having 1 to 6 carbon atoms. P is a positive number in the range of 5 to 1,000.)
Organohydrogenpolysiloxane represented by:
{The number of Si-H groups combined of component (B) and component (C)} / {the number of alkenyl groups of component (A)} is in the range of 0.6 to 1.5, and {component ( C) the number of Si—H derived} / {the number of Si—H derived from component (B)} is in the range of 1.0 to 10.0,
(D) Thermally conductive filler having a thermal conductivity of 10 W / m ° C. or higher:
800 to 2,000 parts by mass,
(E) a 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,
(F) A control agent selected from an acetylene compound, a nitrogen compound, an organic phosphorus compound, an oxime compound and an organic chloro compound: 0.01 to 1 part by mass,
(G) Isoparaffinic solvent having a boiling point of 270 to 350 ° C. capable of dispersing or dissolving the components (A) to (F): 0.1 to 40.0 parts by mass, and a viscosity at 25 ° C. of 50 to 50 ° C. A thermally conductive silicone grease composition having a viscosity of 1,000 Pa · s.
[2] Furthermore, the following general formula (3)
R ³ _a R ⁴ _b Si (OR ⁵ ) _4-ab (3)
(Wherein R ³ is an alkyl group having 6 to 15 carbon atoms, R ⁴ is a monovalent hydrocarbon group having 1 to 8 carbon atoms, R ⁵ is independently an alkyl group having 1 to 6 carbon atoms, and a is 1 An integer of .about.3, b is an integer of 0 to 2, and a + b is an integer of 1 to 3.)
The heat conductive silicone grease composition according to [1], comprising 0.01 to 30.0 parts by mass of the organosilane represented by the formula (A) with respect to 100 parts by mass of the component (A).
[3] Furthermore, the following general formula (4)

Wherein R ⁶ is independently an unsubstituted or substituted monovalent hydrocarbon group, R ⁷ is independently an alkyl group, an alkoxyalkyl group, an alkenyl group or an acyl group, and q is an integer of 5 to 100 And c is an integer of 1 to 3.)
The heat conductive silicone grease composition according to [1] or [2], comprising 0.01 to 30.0 parts by mass of the organopolysiloxane represented by formula (A) with respect to 100 parts by mass of the component (A).

According to the present invention, by using a small amount of a volatile solvent, the filling amount of the filler is increased more than ever while maintaining the viscosity of the composition low, and the heat of the cured product of the composition is increased. A thermally conductive silicone grease composition that can also improve conductivity is obtained.
Since the thermally conductive silicone grease composition of the present invention is paste-like and extensible, it is interposed between the IC package and the heat radiating body, and when the heat radiating body is pressed and fixed from above, the IC package and the heat radiating composition are disposed. Even when unevenness exists on the surface of the body, the gap can be uniformly filled with the composition by pressing. In addition, it is hardened and adhered by heat generated by the IC package, and the flexibility is not lost over time, so the heat dissipation effect can be demonstrated reliably without peeling, improving the reliability of the entire electronic component Can be made.

（式中、Ｒ¹は独立に炭素数１〜６のアルキル基である。ｎ，ｍは０．０１≦ｎ／（ｎ＋ｍ）≦０．３を満足する正数である。）
で示されるオルガノハイドロジェンポリシロキサン、
（Ｃ）下記一般式（２）

（式中、Ｒ²は独立に炭素数１〜６のアルキル基である。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、
（Ｄ）１０Ｗ／ｍ℃以上の熱伝導率を有する熱伝導性充填剤、
（Ｅ）白金及び白金化合物からなる群より選択される触媒、
（Ｆ）アセチレン化合物、窒素化合物、有機りん化合物、オキシム化合物及び有機クロロ化合物より選択される制御剤、
（Ｇ）前記成分（Ａ）〜（Ｆ）を分散又は溶解できる沸点が８０〜３６０℃の揮発性溶剤
を含有してなり、２５℃の粘度が５０〜１，０００Ｐａ・ｓのものである。 This will be described in detail below.
The thermally conductive silicone grease composition of the present invention comprises:
(A) an organopolysiloxane having at least two alkenyl groups in one molecule and having a kinematic viscosity at 25 ° C. of 10 to 100,000 mm ² / s,
(B) The following general formula (1)

(In the formula, R ¹ is independently an alkyl group having 1 to 6 carbon atoms. N and m are positive numbers satisfying 0.01 ≦ n / (n + m) ≦ 0.3.)
An organohydrogenpolysiloxane represented by
(C) The following general formula (2)

(In the formula, R ² is independently an alkyl group having 1 to 6 carbon atoms. P is a positive number in the range of 5 to 1,000.)
An organohydrogenpolysiloxane represented by
(D) a thermally conductive filler having a thermal conductivity of 10 W / m ° C. or higher,
(E) a catalyst selected from the group consisting of platinum and platinum compounds;
(F) a control agent selected from acetylene compounds, nitrogen compounds, organic phosphorus compounds, oxime compounds and organic chloro compounds,
(G) A volatile solvent having a boiling point of 80 to 360 ° C. capable of dispersing or dissolving the components (A) to (F) is contained, and a viscosity at 25 ° C. is 50 to 1,000 Pa · s.

  The organopolysiloxane of component (A) has at least two alkenyl groups directly bonded to silicon atoms in one molecule, and may be linear or branched, or a mixture of two or more different 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 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.

  Examples of the remaining organic group bonded to the silicon atom include methyl groups, ethyl groups, propyl groups, butyl groups, hexyl groups, alkyl groups such as dodecyl groups, aryl groups such as phenyl groups, 2-phenylethyl groups, 2-phenylpropoxy groups. An aralkyl group such as a sulfur group is exemplified, and a substituted hydrocarbon group such as a chloromethyl group and a 3,3,3-trifluoropropyl group is also exemplified. Of these, 90 mol% or more is preferably a methyl group from the viewpoint of ease of synthesis and cost.

Since the kinematic viscosity at 25 ° C. of the organopolysiloxane to the storage stability of the lower with the compositions than 10 mm ² / s is deteriorated, extensibility of the resulting composition is larger than 100,000 mm ² / s is deteriorated, is preferably in the range of 10~100,000mm ² / s, more preferably from 100~50,000mm ² / s. In the present invention, the kinematic viscosity is a value at 25 ° C. measured with an Ostwald viscometer.

（式中、Ｒ¹は独立に炭素数１〜６のアルキル基である。ｎ，ｍは０．０１≦ｎ／（ｎ＋ｍ）≦０．３を満足する正数である。） The organohydrogenpolysiloxane of component (B) is represented by the following general formula (1).

(In the formula, R ¹ is independently an alkyl group having 1 to 6 carbon atoms. N and m are positive numbers satisfying 0.01 ≦ n / (n + m) ≦ 0.3.)

  If n / (n + m) of the organohydrogenpolysiloxane represented by the general formula (1) is smaller than 0.01, the composition cannot be reticulated by crosslinking, and if it is larger than 0.3, unreacted Si- after the initial curing. Since the H group remains and the excess crosslinking reaction proceeds with time due to moisture and the like, and the flexibility of the composition is lost, it is in the range of 0.01 to 0.3, preferably 0.05 to 0.2. The range is good.

R ¹ is an alkyl group having 1 to 6 carbon atoms 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 in terms of ease of synthesis and cost. % Or more is preferably a methyl group.

（式中、Ｒ²は独立に炭素数１〜６のアルキル基である。ｐは５〜１，０００の範囲の正数である。） The organohydrogenpolysiloxane of component (C) is represented by the following general formula (2).

(In the formula, R ² is independently an alkyl group having 1 to 6 carbon atoms. P is a positive number in the range of 5 to 1,000.)

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

R ² is an alkyl group having 1 to 6 carbon atoms 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 in terms of ease of synthesis and cost. % Or more is preferably a methyl group.

The blending amount of the component (B) and the component (C) is the number of Si—H groups in the component (B) and the component (C) with respect to the number of alkenyl groups in the component (A), that is, {component (B ) And the number of Si-H groups of component (C)} / {number of alkenyl groups of component (A)} is preferably in the range of 0.6 to 1.5, preferably 0.7 to 1. A range of 4 is good. If it is less than 0.6, a sufficient network structure cannot be obtained, and the required hardness cannot be obtained after curing. If it is more than 1.5, unreacted Si-H groups are hardened due to excessive crosslinking reaction due to moisture or the like. The flexibility of the composition is lost.
The ratio of the component (B) and the component (C) is such that {number of Si—H derived from the component (C)} / {number of Si—H derived from the component (B)} is 1.0 to 10. A range of 0 is good, and a range of 1.2 to 8.0 is preferred. If the ratio is greater than 10.0, curing will be insufficient.

  The thermally conductive filler of component (D) is for imparting thermal conductivity to the present invention. In the filler of the present invention, when the thermal conductivity of the filler is less than 10 W / m ° C., the thermal conductivity of the thermally conductive silicone grease composition itself becomes small. Therefore, the thermal conductivity of the filler is 10 W / m. m ° C. or higher, particularly 15 to 10,000 W / m ° C. is preferable.

  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, but any filler may be used as long as the thermal conductivity is 10 W / m ° C. or more, and one kind may be used alone, or two or more kinds may be mixed.

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. The range of 0.1 to 100 μm is preferable, and the range of 1 to 80 μm is more 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.

  If the amount of the heat conductive filler is less than 800 parts by mass, the desired thermal conductivity cannot be obtained, and if it is greater than 2,000 parts by mass, it does not become grease and has poor extensibility. It is the range of -2,000 mass parts, Preferably it is the range of 1,000-1,900 mass parts.

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, platinum coordination compounds, and the like.
If the amount of component (E) is less than 0.1 ppm as platinum atoms with respect to the mass of component (A), there is no effect as a catalyst. The range is from 1 to 500 ppm, and the range from 10 to 400 ppm is particularly preferable.

The control agent of component (F) suppresses the catalytic activity of component (E), 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 in the range of 0.01 to 1 part by mass, and particularly preferably in the range of 0.1 to 0.8 part by mass. 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 volatile solvent of the component (G) has a boiling point of 270 to 350 ° C. for dispersing or dissolving the components (A), (B), (C), (D), (E) and (F). From the viewpoint of health, an isoparaffin solvent is preferred.
Incidentally, the boiling point of the volatile solvent is Noto also at 270 to 350 ° C.. If the boiling point of the volatile solvent is less than 80 ° C., the volatilization becomes too fast and the viscosity of the composition increases during operation. On the other hand, when the boiling point exceeds 360 ° C., the solvent tends to remain in the silicone grease composition, and voids are generated, and the thermal characteristics are deteriorated.

  The compounding quantity of the said volatile solvent is 0.1-40 mass parts with respect to 100 mass parts of component (A), 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 cannot be lowered sufficiently, and if it exceeds 40 parts by mass, it is difficult to cure.

  By the way, the thermal conductivity of the thermally conductive silicone grease composition is basically correlated with the blending amount of the thermally conductive filler, and the thermal conductivity is improved as the blending amount of the thermally conductive filler is increased. On the other hand, since the viscosity of the thermally conductive silicone grease composition itself increases when the blending amount of the thermally conductive filler is large, the upper limit is imposed on the blending amount of the thermally conductive filler in consideration of workability and handling properties. There is. Therefore, by blending a small amount of component (G), the viscosity of the thermally conductive silicone grease composition is drastically lowered, and workability and handling are improved even if the blended amount of the thermally conductive filler is larger than that of the conventional composition. Can be secured.

The composition of the present invention has the following general formula (3) which improves the wettability of the filler and the silicone component.
R ³ _a R ⁴ _b Si (OR ⁵ ) _4-ab (3)
(Wherein R ³ is an alkyl group having 6 to 15 carbon atoms, R ⁴ is a monovalent hydrocarbon group having 1 to 8 carbon atoms, R ⁵ is independently an alkyl group having 1 to 6 carbon atoms, and a is 1 An integer of -3, b is an integer of 0-2, and a + b is an integer of 1-3.)
It is more effective to additionally use an organosilane represented by

Specific examples of R ³ in the above general formula (3) of the organosilane used as the wettability improver include, for example, hexyl group, octyl group, nonyl group, decyl group, dodecyl group, tetradecyl group and the like having 6 to 6 carbon atoms. There are 15 alkyl groups. 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.

R ⁴ in the above formula is a saturated or unsaturated monovalent hydrocarbon group having 1 to 8 carbon atoms. Examples of such a group include a methyl group, an ethyl group, a propyl group, a hexyl group, Alkyl groups such as octyl group, cycloalkyl groups such as cyclopentyl group and cyclohexyl group, alkenyl groups such as vinyl group and allyl group, aryl groups such as phenyl group and tolyl group, aralkyl groups such as 2-phenylethyl group, 3, Halogenated hydrocarbon groups such as 3,3-trifluoropropyl group, 2- (nonafluorobutyl) ethyl group , p -chlorophenyl group and the like can be mentioned, and methyl group and ethyl group are particularly preferable.

R ⁵ is an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, or a hexyl group, and a methyl group or an ethyl group is particularly preferable.
Moreover, although a is 1, 2, or 3, it is especially preferable that it is 1.

Specific examples of the organosilane represented by the general formula (3) 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

  When this organosilane is used, the blending amount is less than 0.01 parts by weight with respect to 100 parts by weight of the component (A), and the wettability may be poor. Since the effect does not increase and it is uneconomical, the range of 0.01 to 30 parts by mass is preferable, and 10 to 25 parts by mass is more preferable.

（式中、Ｒ⁶は独立に非置換又は置換の１価炭化水素基であり、Ｒ⁷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の整数であり、ｃは１〜３の整数である。） In the composition of the present invention, it is also effective to additionally use an organopolysiloxane represented by the following general formula (4) that improves the wettability of the filler and the silicone component.

(Wherein, R ⁶ is an unsubstituted or substituted monovalent hydrocarbon group independently, R ⁷ is independently an alkyl group, an alkoxyalkyl group, an alkenyl group or an acyl group, q is an integer of 5 to 100 And c is an integer of 1 to 3.)

R ^{6 in} the above general formula of the organopolysiloxane used as the wettability improver is independently an unsubstituted or substituted monovalent hydrocarbon group, preferably having 1 to 18 carbon atoms. A linear alkyl group, a branched alkyl group, a cyclic alkyl group, an alkenyl group, an aryl group, an aralkyl group, a halogenated alkyl group, and the like. 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. A methyl group and a phenyl group are preferable.

R ⁷ 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 linear alkyl groups, branched alkyl groups, and cyclic alkyl groups similar to those exemplified for R ⁶ . 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 ⁷ is preferably an alkyl group, and particularly preferably a methyl group or an ethyl group.
q is an integer of 5 to 100. c is an integer of 1 to 3, and is preferably 3.

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

  When this organopolysiloxane is used, the blending amount is less than 0.01 parts by weight with respect to 100 parts by weight of the component (A), and the wettability may be poor, and the blending amount may be more than 30 parts by weight. The effect is not increased and it is uneconomical, so the range of 0.01 to 30 parts by mass is preferable, and 10 to 25 parts by mass is more preferable.

  In addition to the above-described components, the present invention may contain an adhesion aid or the like for chemically bonding and fixing an IC package such as a CPU and a heat sink such as a heat sink, if necessary. In order to prevent deterioration, an antioxidant or the like may be added.

  The thermally conductive silicone grease composition of the present invention comprises the above components (A) to (G) and, if necessary, an organosilane of the general formula (3), an organopolysiloxane of the general formula (4), and other additives. Etc. can be prepared by mixing according to a conventional method, and can be stored at a low temperature for a long time as a one-component addition type.

  At the time of assembling the semiconductor device of the present invention, this thermally conductive silicone grease 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 at 25 ° C. is lower than 50 Pa · s, dripping will occur at the time of application, and if it is higher than 1,000 Pa · s, the application efficiency will deteriorate, so it is used in the range of 50 to 1,000 Pa · s. Although possible, it is preferably 100 to 400 Pa · s. In the present invention, the viscosity is a value measured at 25 ° C. with a rotational viscometer.

  After being dispensed, it is cured by heat generated from the IC package, and after curing, this composition has tackiness so that it does not slip and does not peel off from the substrate because it has a stable flexibility over time. . Further, after dispensing, the resin may be positively heated and cured. In this case, the heat curing conditions are not particularly limited, and can be, for example, 100 to 150 ° C. and about 10 to 120 minutes.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example. In the following, Me represents a methyl group.

[Examples 1-9, Comparative Examples 1-9]
First, the following components for forming the composition of the present invention were prepared.
Ingredient (A)
A-1: Dimethylpolysiloxane having both ends blocked with dimethylvinylsilyl groups and a kinematic viscosity at 25 ° C. of 600 mm ² / s

Ｂ−２：

Ｂ−３（比較用）：

Ｂ−４（比較用）：

Component (B) Organohydrogenpolysiloxane B-1 represented by the following formula:

B-2:

B-3 (for comparison):

B-4 (for comparison):

Ｃ−２：

Component (C) Organohydrogenpolysiloxane C-1 represented by the following formula:

C-2:

Ingredient (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 5 were obtained.
Aluminum powder with an average particle size of 4.9 μm (thermal conductivity: 237 W / m ° C. (300 K))
Aluminum powder with an average particle size of 15.0 μm (thermal conductivity: 237 W / m ° C. (300 K))
Alumina powder with an average particle size of 15.0 μm (thermal conductivity: 36 W / m ° C. (300 K))
Zinc oxide powder with an average particle size of 1.0 μm (thermal conductivity: 116 W / m ° C. (300 K))

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

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

Ingredient (G)
G-1: IP solvent 2835 (isoparaffin solvent, trade name, manufactured by Idemitsu Kosan Co., Ltd.) Boiling point 270-350 ° C

(Organosilane used)
Organosilane (1): C ₆ H ₁₃ Si (OCH ₃ ) ₃
Organosilane (2): C ₁₀ H ₂₁ Si (OCH ₃ ) ₃

(Used organopolysiloxane)
Organopolysiloxane (1):

Components (A) to (G) were mixed as follows to obtain a silicone composition.
That is, the components (A), (B), (C), and (G) were added to a 5 liter gate mixer (trade name: 5 liter planetary mixer manufactured by Inoue Seisakusho Co., Ltd.) in the blending amounts shown in Tables 2 and 3. Weighed out and further weighed out component (D), added organosilane and organopolysiloxane as needed, 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 at room temperature for 15 minutes so as to be uniform.

  Using the obtained composition, the thermal conductivity, viscosity, applicability, and hardness were measured by the evaluation methods shown below. These results are shown in Tables 2 and 3.

Thermal conductivity:
The thickness of the test piece was measured with a micrometer (manufactured by Mitutoyo Corporation), and the thickness of the two aluminum plates that had been measured in advance was subtracted to calculate the thickness of the composition. 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.

Applicability:
The manufactured heat conductive silicone grease composition was packed in 30 cc of an EFD syringe. Then, as a dispenser, MUSASHI ENGINEERING, INC. ML606-GX made from this company was used, the discharge pressure was 0.50 MPa, and the discharge test was done. Evaluation results are shown as “Good” in “Discharge performance”, and “No” in “Discharge difficult”.

Hardness measurement:
The flexibility of the cured product 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 produce a 10 mm thick sheet-like rubber molded product. The molded product was returned to 25 ° C. and the initial hardness was measured. Subsequently, after being left 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. The hardness was measured using Asker C (for low hardness) manufactured by Kobunshi Keiki Co., Ltd.

Claims (3)

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

(In the formula, R ¹ is independently an alkyl group having 1 to 6 carbon atoms. N and m are positive numbers satisfying 0.01 ≦ n / (n + m) ≦ 0.3.)
An organohydrogenpolysiloxane represented by
(C) The following general formula (2)

(In the formula, R ² is independently an alkyl group having 1 to 6 carbon atoms. P is a positive number in the range of 5 to 1,000.)
Organohydrogenpolysiloxane represented by:
{The number of Si-H groups combined of component (B) and component (C)} / {the number of alkenyl groups of component (A)} is in the range of 0.6 to 1.5, and {component ( C) the number of Si—H derived} / {the number of Si—H derived from component (B)} is in the range of 1.0 to 10.0,
(D) Thermally conductive filler having a thermal conductivity of 10 W / m ° C. or higher:
800 to 2,000 parts by mass,
(E) a 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,
(F) A control agent selected from an acetylene compound, a nitrogen compound, an organic phosphorus compound, an oxime compound and an organic chloro compound: 0.01 to 1 part by mass,
(G) Isoparaffinic solvent having a boiling point of 270 to 350 ° C. capable of dispersing or dissolving the components (A) to (F): 0.1 to 40.0 parts by mass, and a viscosity at 25 ° C. of 50 to 50 ° C. A thermally conductive silicone grease composition having a viscosity of 1,000 Pa · s. Furthermore, the following general formula (3)
R ³ _a R ⁴ _b Si (OR ⁵ ) _4-ab (3)
(Wherein R ³ is an alkyl group having 6 to 15 carbon atoms, R ⁴ is a monovalent hydrocarbon group having 1 to 8 carbon atoms, R ⁵ is independently an alkyl group having 1 to 6 carbon atoms, and a is 1 An integer of .about.3, b is an integer of 0 to 2, and a + b is an integer of 1 to 3.)
The heat conductive silicone grease composition of Claim 1 which contains 0.01-30.0 mass parts with respect to 100 mass parts of (A) component. Furthermore, the following general formula (4)

Wherein R ⁶ is independently an unsubstituted or substituted monovalent hydrocarbon group, R ⁷ is independently an alkyl group, an alkoxyalkyl group, an alkenyl group or an acyl group, and q is an integer of 5 to 100 And c is an integer of 1 to 3.)
The heat conductive silicone grease composition of Claim 1 or 2 which contains 0.01-30.0 mass parts with respect to 100 mass parts of (A) component for the organopolysiloxane shown by these.