JP2013010862A - Curable and grease-like thermoconductive silicone composition and semiconductor device - Google Patents

Abstract

Disclosed is a curable, grease-like thermally conductive silicone composition that is uniformly dispersed in a matrix composed of a resin component in the form of fine particles having excellent thermal conductivity.
(A) Organopolysiloxane having two or more alkenyl groups bonded to silicon in one molecule: 100 parts by mass, (B) Organo having two or more hydrogen atoms bonded to silicon in one molecule Hydrogen polysiloxane, (C) gallium and / or gallium alloy having a melting point of 0 to 70 ° C., (D) silver powder having an average particle size of 0.1 to 100 μm, and the sum of (C) component and (D) component is It is 300-5000 mass parts, and these are (C) component / {(C) component + (Dcomponent)} = 0.1-0.9 in mass ratio. (F) A curable grease-like thermally conductive silicone composition containing a platinum-based catalyst and (G) an addition reaction control agent.
[Selection figure] None

Description

  The present invention relates to a curable and grease-like thermally conductive silicone composition, a production method thereof, a cured product thereof, use of the cured product as a thermally conductive layer, a semiconductor device having the thermally conductive layer, and the semiconductor The present invention relates to a device manufacturing method.

  Heat-generating electronic components mounted on a printed circuit board, for example, IC packages such as CPUs, may suffer performance degradation or damage due to temperature rise due to heat generation during use. A heat conductive sheet with good thermal conductivity is arranged between the fin and the heat dissipation member, or heat conductive grease is applied to efficiently conduct the heat generated from the IC package etc. to the heat dissipation member. It is implemented to dissipate heat. However, as the performance of electronic parts and the like increases, the amount of generated heat tends to increase more and more, and development of materials and members that are more excellent in thermal conductivity than conventional ones is required.

  The conventional heat conductive sheet has an advantage in work and process that it can be easily mounted and mounted. Further, in the case of thermally conductive grease, the two are closely contacted without following the unevenness without being affected by the unevenness of the surface of the CPU, heat radiating member, etc., without causing a gap between the two. There is an advantage that the interfacial thermal resistance is small. However, both the heat conductive sheet and the heat conductive grease are obtained by blending a heat conductive filler in order to impart heat conductivity. In the case of a heat conductive sheet, workability and processing in the manufacturing process are obtained. In the case of thermally conductive grease, the appearance of the heat-sensitive electronic parts should not be affected by the use of a syringe. Since it is necessary to suppress the upper limit of the viscosity to a certain limit, in any case, the upper limit of the blending amount of the heat conductive filler is limited, and there is a drawback that a sufficient heat conductive effect cannot be obtained.

  Therefore, a method of blending a low melting point metal in the heat conductive paste (Patent Document 1, Patent Document 2), a granular material that functions to fix and stabilize the liquid metal in the three-phase composite (Patent Document 3). ) Etc. have been proposed. However, these thermally conductive materials using low-melting point metals have problems such as contamination of parts other than the coated part and leakage of oil when used for a long time.

  In addition, as a method for solving these problems, a material for dispersing gallium in silicone and making it a cured product has been proposed (Patent Document 4). However, when the thickness of the composition is increased, good thermal resistance is hardly expressed. There was a problem.

JP-A-7-207160 JP-A-8-53664 JP 2002-121292 A JP 2005-112961 A

  In light of the above-described prior art, the main object of the present invention is to blend a sufficient amount of a material having excellent heat conduction characteristics, and to disperse the material uniformly in a matrix composed of resin components in the form of fine particles. The object is to obtain a curable and grease-like thermally conductive silicone composition. Moreover, it is providing the method of manufacturing this composition.

A curable grease-like thermally conductive silicone composition is arranged so as to be sandwiched between a heat-generating electronic component and a heat-dissipating member, as with conventional heat-conductive grease, and follows the irregularities on the surface of the component or member. Thus, there is provided a use as a heat conductive layer made of a cured product that is crosslinked by heat treatment without causing a gap. Furthermore, the objective of this invention is providing the semiconductor device excellent in the heat dissipation performance in which the exothermic electronic component and the heat radiating member were joined via the said heat conductive layer, and its manufacturing method.

  As a result of intensive studies to achieve the above object, the inventors have selected low melting point gallium and / or gallium alloy and specific silver powder as a material having excellent heat conduction characteristics, and added this to an addition reaction hardening type. It has been found that a composition in which the gallium and / or gallium alloy is uniformly dispersed in a fine particle state can be obtained by blending with the organopolysiloxane composition.

  Further, in the step of heat-treating the composition to obtain a cured product, the liquid gallium and / or gallium alloy is connected to the silver powder by fusing to form a kind of continuous path, The present inventors have found that the path-like structure is fixed and held in a crosslinked network formed by curing the resin component.

  And by arranging the cured product obtained as described above in a layered manner so as to be sandwiched between the exothermic electronic component and the heat radiating member, it can be used as a heat conductive layer having a low thermal resistance, Heat generated during the operation of the thermal electronic component is quickly transferred to the heat radiating member via the thermal conductive layer composed of gallium and / or gallium alloy fixed and held in the structure as described above and silver powder. The inventors have obtained knowledge that a semiconductor product that conducts and has excellent heat dissipation characteristics can be obtained, and based on these findings, the present invention has been completed.

That is, the present invention firstly
(A) Organopolysiloxane having two or more alkenyl groups bonded to silicon atoms in one molecule and having a viscosity at 25 ° C. of 0.05 to 100 Pa · s: 100 parts by mass
(B) Organohydrogenpolysiloxane having two or more hydrogen atoms bonded to a silicon atom: One alkenyl group in the component (A) bonded to a silicon atom in the component An amount such that the number of hydrogen atoms is 0.1 to 5.0,
(C) Gallium and / or a gallium alloy having a melting point of 0 to 70 ° C.
(D) a silver powder having an average particle size of 0.1 to 100 μm,
The sum total of (C) component and (D) component is 300-5000 mass parts, and these are (C) component / {(C) component + (D) component)} = 0.1-0.9 in mass ratio. It is.
(E) Thermally conductive filler having an average particle diameter of 0.1 to 100 μm other than silver: 0 to 1000 parts by mass,
(F) A platinum-based catalyst: an effective amount, and (G) an addition reaction control agent: A thermally conductive silicone composition containing an effective amount is provided.

Secondly, the present invention provides a method for producing the composition.
Thirdly, the present invention provides a thermally conductive cured product of the composition.
Fourthly, the present invention provides use of the thermally conductive cured product as a thermally conductive layer disposed between a heat generating electronic component and a heat radiating member.

Fifth, the present invention provides a semiconductor device comprising a heat-generating electronic component, a heat radiating member, and the heat conductive layer.
Sixth, the present invention provides a method for manufacturing the semiconductor device.

  Since the curable organopolysiloxane composition of the present invention is in the form of a grease or paste before curing, it has good workability when applied onto a heat-generating electronic component such as an IC package, and further a heat dissipation member When press-contacting the two, they can follow the unevenness of the surfaces of the two and can be brought into close contact with each other without generating a gap therebetween, so that no interfacial thermal resistance is generated.

  In addition, in the heat treatment step for curing the resin component by addition reaction, the gallium and / or gallium alloy is connected to the silver powder by fusing to form a kind of continuous path, and the resin component is cured. Since the path-like structure is fixed and held in the three-dimensional cross-linked network formed by the above, the heat generated from the heat-generating electronic component can be quickly conducted to the heat radiating member. Higher heat dissipation effect can be surely exhibited than the conductive sheet or the heat conductive grease. Since this kind of connected and connected route is fixed and held in the three-dimensional cross-linked network of cured resin, it is another problem that has been a problem in the case of conventional non-curable thermal conductive grease. Parts are not contaminated, and oil does not leak over time. Therefore, the reliability of the semiconductor device can be further improved.

It is a longitudinal section schematic diagram showing an example of a semiconductor device to which the composition of the present invention is applied.

[Curable grease-like thermally conductive silicone composition]
<(A) Organopolysiloxane>
The component (A) of the composition of the present invention is an organopolysiloxane having two or more alkenyl groups bonded to silicon atoms in one molecule, and is the main agent (base polymer) in the addition reaction curing system of the present invention.

  The molecular structure of the organopolysiloxane is not limited as long as it is liquid at room temperature, and examples thereof include a straight chain, a branched chain, and a partially branched straight chain, and a linear chain is particularly preferable. .

  Examples of the alkenyl group include a vinyl group, an allyl group, a 1-butenyl group, and a 1-hexenyl group. Among these, a vinyl group having high versatility is preferable. This alkenyl 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, but the silicon atom at the end of the molecular chain is used to make the resulting cured product flexible. It is preferable that it is bonded only to.

  Examples of the group bonded to the silicon atom other than the alkenyl group in the component (A) include an unsubstituted or substituted monovalent hydrocarbon group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group. Group, heptyl group, octyl group, nonyl group, decyl group, dodecyl group and other alkyl groups; cyclopentyl group, cyclohexyl group and other cycloalkyl groups; phenyl group, tolyl group, xylyl group, naphthyl group and other aryl groups; benzyl group Aralkyl groups such as 2-phenylethyl group and 2-phenylpropyl group; halogenated alkyl groups such as chloromethyl group, 3,3,3-trifluoropropyl group and 3-chloropropyl group. Of these, 90% or more are preferably methyl groups from the viewpoint of synthesis and economy.

  The viscosity of this organopolysiloxane at 25 ° C. is usually in the range of 0.05 to 100 Pa · s, particularly preferably 0.5 to 50 Pa · s. If the viscosity is too low, the storage stability of the resulting composition will be poor, and if it is too high, the extensibility of the resulting composition may be poor.

  Preferable specific examples of such organopolysiloxanes include dimethylvinylsiloxy group-capped polydimethylsiloxane having molecular chains at both ends, methyldivinylsiloxy group-capped polydimethylsiloxane having molecular chains at both ends, and dimethylvinylsiloxy-capped dimethylsiloxane having molecular chains at both ends. -A methylphenylsiloxane copolymer etc. are mentioned.

  The organopolysiloxane of component (A) can be used singly or in combination of two or more having different viscosities.

<(B) Organohydrogenpolysiloxane>
Component (B) of the composition of the present invention is an organohydrogenpolysiloxane having two or more hydrogen atoms bonded to silicon atoms (hereinafter referred to as “SiH”) in one molecule. It acts as a crosslinking agent. That is, the SiH in the component (B) is added by the hydrosilylation reaction with the alkenyl group in the component (A) by the action of the platinum catalyst of the component (F) described later, and has a three-dimensional network structure having a crosslink. A cross-linked cured product having

  (B) As a group couple | bonded with silicon atoms other than a hydrogen atom in a component, it is an unsubstituted or substituted monovalent hydrocarbon group other than an alkenyl group, for example, The group similar to what was illustrated about (A) component Is mentioned. Among these, a methyl group is preferable from the viewpoint of synthesis and economy.

  In addition, the structure of the organohydrogenpolysiloxane may be linear, branched or cyclic.

  (B) Component specific examples of the organohydrogenpolysiloxane include molecular chain both ends trimethylsiloxy group-blocked methylhydrogenpolysiloxane, molecular chain both ends trimethylsiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer Copolymer, dimethylsiloxane / methylhydrogensiloxane / methylphenylsiloxane copolymer blocked at both ends of molecular chain, dimethylpolysiloxane / blocked at both ends of molecular chain, dimethylpolysiloxy group blocked at both ends of molecular chain Siloxane / methylhydrogensiloxane copolymer, dimethylhydrogensiloxy group-blocked dimethylsiloxane / methylphenylsiloxane copolymer, both ends of the molecular chain dimethylhigh Rojienshirokishi group-blocked methyl phenylalanine polysiloxane and the like. Moreover, the organohydrogenpolysiloxane of the component (B) can be used singly or in combination of two or more.

  The blending amount of the component (B) is such that the number of hydrogen atoms bonded to silicon atoms in the component is 0.1 to 5.0 with respect to one alkenyl group in the component (A). Yes, and preferably in an amount of 0.5 to 3.0. If the number is less than 0.1, a sufficient network structure is not formed, so that the hardness required after curing cannot be obtained, and the components (C) and (D) described below are fixed and held. It becomes difficult. On the other hand, if the number exceeds 5.0, the change over time in the physical properties of the resulting cured product becomes large, and the storage stability may deteriorate.

<(C) Gallium and / or gallium alloy>
The component (C) of the composition of the present invention is gallium and / or a gallium alloy having a melting point of 0 to 70 ° C. This (C) component is a component mix | blended in order to provide favorable thermal conductivity to the hardened | cured material obtained from this invention composition.

  As described above, the melting point of the component (C) needs to be in the range of 0 to 70 ° C. After preparing the composition of the present invention, a low temperature state of about −30 to −10 ° C., preferably −25 to −15 ° C. during long-term storage and transportation in order to maintain the dispersion state of each component contained in the composition. However, when the melting point is less than 0 ° C., the component (C) is melted and liquefied when stored and transported for a long time as described above, and the resulting liquid fine particles tend to aggregate. Thus, it becomes relatively difficult to maintain the state at the time of preparation of the composition. Conversely, if the temperature exceeds 70 ° C., the composition preparation step (step (i) described later) does not melt quickly, resulting in poor workability. Therefore, as described above, the range of 0 to 70 ° C. is an appropriate range as well as a condition necessary for handling. The thing in the range of 15-50 degreeC is especially preferable.

The melting point of metallic gallium is 29.8 ° C. Examples of typical gallium alloys include gallium-indium alloys; for example, Ga-In (mass ratio = 75.4: 24.6, melting point = 15.7 ° C.), gallium-tin alloys, gallium-tin. -Zinc alloy; for example, Ga-Sn-Zn (mass ratio = 82: 12: 6, melting point = 17 ° C.), gallium-indium-tin alloy; for example, Ga-In-Sn (mass ratio = 21.5: 16) 0.0: 62.5, melting point = 10.7 ° C.), gallium-indium-bismuth-tin alloy; for example, Ga—In—Bi—Sn (mass ratio = 9.4: 47.3: 24.7: 18) .6, melting point = 48.0 ° C.).
This component (C) can be used alone or in combination of two or more.

  The shape of the liquid fine particles or solid fine particles of gallium and / or gallium alloy present in the composition of the present invention in an uncured state is substantially spherical and may include irregular shapes. Moreover, it is preferable that the average particle diameter is 0.1-100 micrometers normally, especially 5-70 micrometers. If the average particle size is too small, the viscosity of the composition will be too high, and the extensibility will be poor, so there will be a problem in coating workability, and conversely if it is too large, the composition will be non-uniform. It becomes difficult to apply a thin film to exothermic electronic components. The shape and average particle size, as well as the dispersion state in the composition, are maintained at a low temperature immediately after preparation of the composition as described above. can do.

<(D) Silver powder>
The silver powder of the present invention is effective for forming a kind of continuous path by fusing with the component (C). If the average particle size of the silver powder is smaller than 0.1 μm, it tends to aggregate, and if it is larger than 100 μm, it becomes difficult to obtain a uniform composition, so it is 0.1 to 100 μm, preferably 0.5 to 70 μm. It is a range. The shape of the silver powder is not particularly limited and may be flaky or spherical. Here, the average particle diameter of the silver powder particles means a volume-based 50% particle diameter, and can be measured by, for example, a microtrack particle size analyzer (manufactured by Nikkiso Co., Ltd.). Further, the component (D) can be used alone or in combination of two or more.

  The total amount of the component (C) and the component (D) is 300 to 5000 parts by mass, preferably 500 to 3000 parts by mass with respect to 100 parts by mass of the component (A). If the blending amount is less than 300 parts by mass, the viscosity of the resulting composition is too low to be substantially grease-like, and a heat conductive layer having a necessary thickness is formed on a heat-generating electronic component or the like. Therefore, it is difficult to obtain a cured product layer having sufficient thermal conductivity. On the other hand, if it is too much, it becomes difficult to obtain a uniform composition, and the viscosity of the composition becomes too high, so that the composition cannot be obtained as a grease-like one that is also extensible. There is a problem.

The ratio of the component (C) to the component (D) is desirable because the silver powder tends to aggregate when the mass ratio of the component (C) / {(C) component + (D) component)} is less than 0.1. Thermal resistance is not obtained, and if it is greater than 0.9, it is difficult to form a desired heat conductive layer when the composition is thick, and it is difficult to express good thermal resistance. Is preferred. More preferably, it is 0.3-0.9.

<(E) Thermally conductive filler>
In the composition of the present invention, if necessary, together with the components (C) and (D), a conventionally known heat conductive sheet or heat conductive grease is blended with (E) a heat conductive filler. Can be added and blended.

The component (E) is not particularly limited as long as it has a good thermal conductivity other than silver powder, and any conventionally known one can be used. For example, zinc oxide powder, alumina powder Boron nitride powder, aluminum nitride powder, silicon nitride powder, copper powder, diamond powder, nickel powder, zinc powder, stainless steel powder, carbon powder and the like. Moreover, this (E) component can be used even if single 1 type also combines 2 or more types.
The average particle size of the component (E) is usually 0.1 to 100 μm, preferably 1 to 20 μm. If the average particle size is too small, the resulting composition will have too high a viscosity, resulting in poor extensibility. Here, the average particle diameter is as described for the silver powder of component (D). On the other hand, if it is too large, it will be difficult to obtain a uniform composition and it will be easy to separate, so it will not become a grease-like composition.

When using this (E) component, the compounding quantity is 0-1000 mass parts with respect to 100 mass parts of said (A) component, Preferably it is good to set it as 500 mass parts or less. When the blending amount exceeds 1000 parts by mass, the resulting composition has poor extensibility. (E) 50-500 mass parts is preferable in order to acquire the compounding effect of a component.
<(F) Platinum-based catalyst>
The platinum-based catalyst of the component (F) of the composition of the present invention promotes the addition reaction between the alkenyl group in the component (A) and SiH in the component (B), and the three-dimensional network state from the composition of the present invention. It is a component mix | blended in order to give the crosslinked hardened | cured material.

  As the component (F), all known compounds used in ordinary hydrosilylation reactions can be used. For example, platinum metal (platinum black), chloroplatinic acid, platinum-olefin complex, platinum-alcohol complex, Examples include platinum coordination compounds. The compounding amount of the component (F) is not particularly limited as long as it is an effective amount necessary for curing the composition of the present invention. For example, the amount of the component (F) is usually 0. It is good to be about 1-500 ppm.

<(G) Addition reaction control agent>
The addition reaction control agent of the component (G) of the composition of the present invention suppresses the hydrosilylation reaction due to the action of the platinum-based catalyst at room temperature, and ensures the pot life (shelf life, pot life) of the composition of the present invention. Thus, it is a component that is blended so as not to hinder the coating work on the exothermic electronic components.

  As this (G) component, all the known addition reaction control agents used for usual addition reaction curable silicone compositions can be used. For example, 1-ethynyl-1-cyclohexanol, 3-butyne-1 Examples include acetylene compounds such as ol, various nitrogen compounds, organic phosphorus compounds, oxime compounds, and organic chloro compounds.

  The blending amount with the component (G) varies depending on the amount of the component (F) used and cannot be generally specified, but is not particularly limited as long as it is an effective amount capable of suppressing the progress of the hydrosilylation reaction. . For example, it is usually preferable that the amount is about 0.001 to 5 parts by mass with respect to 100 parts by mass of the component (A). If the amount of component (G) is too small, sufficient pot life cannot be ensured, and if too large, the curability of the composition of the present invention will be reduced. In addition, in order to improve the dispersibility in a composition, this (G) component can also be diluted with organic solvents, such as toluene, xylene, isopropyl alcohol, and can be used as needed.

<(H) Surface treatment agent>
In the composition of the present invention, the gallium and / or gallium alloy of the component (C) is hydrophobized at the time of preparing the composition, and the wettability between the liquid particles of the component (C) and the organopolysiloxane of the component (A) is improved. For the purpose of improving and uniformly dispersing the component (C) as fine particles in the matrix comprising the component (A), (H) a surface treatment agent (wetter) can be blended as necessary.

  In addition, when the component (H) uses the silver powder of the component (D) and the thermally conductive filler of the component (E), the surface is similarly improved in wettability and its uniform dispersibility. It also has the effect | action which makes it favorable.

As the component (H), for example, (H-1) the following general formula (1):
R ¹ _a R ² _b Si (OR ³ ) _4-ab (1)
(Wherein R ¹ is independently an alkyl group having 6 to 15 carbon atoms, preferably 8 to 14 carbon atoms, and R ² is independently an unsubstituted or substituted carbon atom having 1 to 8 carbon atoms, preferably 1 to 6 carbon atoms. A monovalent hydrocarbon group, R ³ is independently an alkyl group having 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, a is an integer of 1 to 3, preferably 1, and b is 0 to 2 And the sum of a + b is an integer of 1 to 3.)
The alkoxysilane compound represented by these is mentioned.

Examples of R ¹ in the above formula include hexyl group, octyl group, nonyl group, decyl group, dodecyl group, tetradecyl group and the like. When the number of carbon atoms is less than 6, the wettability of the components (C), (D) and (E) is not sufficiently improved, and when it exceeds 15, the organosilane of the (H-1) component is at room temperature. Therefore, it is inconvenient to handle, and the low temperature characteristics of the resulting composition are deteriorated.

Examples of R ² include alkyl groups such as a methyl group, ethyl group, propyl group, hexyl group, and 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 and tolyl groups; aralkyl groups such as 2-phenylethyl and 2-methyl-2-phenylethyl; 3,3,3-trifluoropropyl and 2- (nonafluorobutyl) ethyl And halogenated hydrocarbon groups such as 2- (heptadecafluorooctyl) ethyl group and p-chlorophenyl group. Among these, a methyl group and an ethyl group are particularly preferable.

Moreover, as said R < ³ >, alkyl groups, such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, are mentioned, for example. Among these, a methyl group and an ethyl group are particularly preferable.

Preferable specific examples of the component (H-1) 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

  The component (H-1) can be used alone or in combination of two or more. Moreover, the compounding quantity becomes like this. Preferably it is 0-20 mass parts with respect to 100 mass parts of (A) component, More preferably, it is 3-10 mass parts. If the amount is too large, the wetter effect does not increase, which is uneconomical and somewhat volatile. If left in an open system, the composition of the present invention may gradually become hard.

  As (H) component other than the above (H-1) component, (H-2) the following general formula (2):

（２）
（式中、Ｒ³は独立に炭素原子数１〜６、好ましくは１〜４のアルキル基であり、ｃは５〜１００、好ましくは１０〜６０の整数である。）
で表される分子鎖の片末端がトリアルコキシシリル基で封鎖されたジメチルポリシロキサンが挙げられる。
上記式中のＲ³としては、上記一般式（１）中のＲ³と同じである。

(2)
(In the formula, R ³ is independently an alkyl group having 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, and c is an integer of 5 to 100, preferably 10 to 60.)
Dimethylpolysiloxane in which one end of a molecular chain represented by the formula is blocked with a trialkoxysilyl group.
R ³ in the above formula is the same as R ³ in the general formula (1).

  The component (H-2) can be used alone or in combination of two or more. Moreover, the compounding quantity becomes like this. Preferably it is 0-100 mass parts with respect to 100 mass parts of (A) component, More preferably, it is 10-50 mass parts. When there is too much the said compounding quantity, the tendency for the heat resistance of the hardened | cured material obtained to fall will come out.

  As the surface treatment agent for the component (H), the component (H-1) and the component (H-2) may be used in combination.

<Other ingredients>
In addition to the above-mentioned components, other components may be added to the composition of the present invention as long as the objects and effects of the present invention are not impaired. For example, a heat resistance improver such as iron oxide or cerium oxide; a viscosity modifier such as silica; a colorant or the like can be blended.

<Viscosity of composition>
As will be described later, the composition of the present invention is applied to the surface of the heat-generating electronic component, and after heat-contacting the heat-dissipating member, the composition is cured by heat treatment to form a heat conductive layer. At this time, in order to improve workability, the composition of the present invention needs to be in the form of grease.

  For example, the composition of the present invention is housed in a syringe, applied from the syringe onto the surface of a heat-generating electronic component such as a CPU to form a coating layer, and a heat radiating member is press-contacted thereto. Accordingly, the viscosity of the composition of the present invention is usually 10 to 1000 Pa · s, preferably 50 to 400 Pa · s. If the viscosity is too low, dripping may occur during the application, which may cause a problem in work. On the other hand, if it is too high, extrusion from the syringe becomes difficult, and the efficiency of the coating operation may be deteriorated.

[Preparation of composition of the present invention]
The curable organopolysiloxane composition of the present invention comprises
(i) the component (A), the component (C), the component (E), the component (H-1), the component (H-1), and the component (H-2) C) a step of kneading at a temperature equal to or higher than the melting point of the component to obtain a uniform mixture;
(ii) stopping kneading and cooling the temperature to below the melting point of the component (C); and
(iii) The component (D), the component (B), the component (F), the component (G), and optionally other components are added, and the temperature below the melting point of the component (C) It can obtain by the manufacturing method including the process of knead | mixing and obtaining a uniform mixture.

  In the manufacturing method, a stirring / kneading machine such as a conditioning mixer or a planetary mixer provided with a heating means and, if necessary, a cooling means is used.

  In step (i), the component (C) gallium and / or gallium alloy prepared as a raw material may be solid or liquid. In the step (i), kneading is performed at a temperature equal to or higher than the melting point of the component (C), so that it is liquefied in the step. The liquid material of component (C) gallium and / or gallium alloy is uniformly dispersed in the matrix composed of component (A) in the form of fine particles. By adjusting the temperature at the time of kneading, the rotational speed of the stirring blade of the stirring / kneading machine, etc., the average particle size of the fine particles can be adjusted appropriately to a desired one.

  The temperature lowering operation or the cooling operation in the step (ii) is preferably performed promptly. In the step (ii), the component (C) in the liquid fine particle state uniformly dispersed in the matrix comprising the component (A) is solidified while maintaining the average particle size and the dispersed state.

  The step (iii) is also preferably completed in as short a time as possible. At the end of the step (iii), the average particle diameter and dispersion state of the solidified fine particles of the component (C) are not substantially changed. And after completion | finish of this process (iii), the produced | generated composition is accommodated in a container, About 30--10 degreeC rapidly, Preferably it is -25--15 degreeC in the freezer, freezer compartment, etc. It is good to save. Further, it is preferable to use a vehicle or the like equipped with a refrigeration facility for the transportation. By storing and transporting at a low temperature as described above, the composition and dispersion state of the composition of the present invention can be stably maintained even after long-term storage, for example.

[Application to semiconductor devices]
A semiconductor device having excellent heat dissipation characteristics using the composition of the present invention, that is, a semiconductor device having a heat-generating electronic component, a heat dissipation member, and a thermally conductive layer made of a cured product of the composition of the present invention. Thus, a semiconductor device in which the exothermic electronic component and the heat radiating member are bonded via the thermally conductive layer can be obtained.

The semiconductor device includes:
(a) applying the composition to the surface of the exothermic electronic component to form a coating layer made of the composition on the surface;
(b) a step of pressing and fixing the heat radiating member to the coating layer; and
(c) It can be obtained by a production method including a step of treating the obtained structure at 80 to 180 ° C. to cure the coating layer to form the heat conductive layer.

  The semiconductor device and the manufacturing method thereof will be described with reference to FIG. The device shown in FIG. 1 is merely an example of application of the composition of the present invention to a semiconductor device, and the semiconductor device according to the present invention is limited to that shown in FIG. Absent.

  First, the composition of the present invention in a frozen storage state is allowed to stand at room temperature and naturally thawed to form a grease. Next, the grease-like composition of the present invention is accommodated in a coating tool such as a syringe.

  A composition of the present invention is applied (dispensed) from a syringe or the like onto the surface of an IC package 2 such as a CPU which is a heat generating electronic component mounted on the printed circuit board 3 shown in FIG. Thus, the coating layer 1 is formed. A heat dissipating member, for example, a heat dissipating member 4 having a heat dissipating fin made of aluminum, for example, is disposed thereon, and the heat dissipating member 4 is pressed and fixed to the IC package 2 through the covering layer 1 using a clamp 5. Let

  At this time, the clamp 5 is adjusted or selected so that the thickness of the coating layer 1 existing between the IC package 2 and the heat dissipation member 4 is usually 5 to 100 μm, particularly preferably 10 to 70 μm. It is good. When the thickness is too thin, the followability of the composition of the present invention to the IC package 2 and the heat radiating member 4 becomes insufficient at the time of the pressure contact, and there is a possibility that a gap is formed between the two. On the other hand, if the thickness is too large, the thermal resistance increases, so that a sufficient heat dissipation effect cannot be obtained.

  Next, the apparatus configured as described above is passed through a heating apparatus such as a reflow furnace, and the coating layer 1 made of the composition of the present invention is cured to form a heat conductive layer. The temperature condition required for this curing is 80 to 180 ° C, particularly preferably 100 to 150 ° C. When the temperature is less than 80 ° C., curing becomes insufficient. Conversely, when the temperature is higher than 180 ° C., the electronic component or the substrate may be deteriorated.

  Further, in the step of heat-treating the composition to obtain a cured product, the liquid gallium and / or gallium alloy is connected to the silver powder by fusing to form a kind of continuous path, The route-like structure is fixed and held in a crosslinked network formed by curing the resin component.

  In the process of raising the temperature to the temperature condition during the curing, the gallium and / or gallium alloy of the component (C) in the composition of the present invention forms a kind of continuous connection by fusing with the silver powder. To do.

  Further, the path is also fused to the surfaces of the IC package 2 and the heat radiating member 4 that are in contact with each other. Therefore, the IC package 2 and the heat radiating member 4 have substantially continuous heat conductivity through a kind of path in which the component (C) and the component (D) are connected and connected. It will be rich. The path-like structure is fixed and held in a three-dimensional crosslinked network of a cured product formed by the addition reaction of the component (A) and the component (B).

  Further, when the semiconductor device obtained as described above is operated and used, the surface temperature of the heat-generating electronic component such as an IC package is usually about 60 to 120 ° C. For this heat generation, the heat conductive layer made of the cured product of the composition of the present invention exhibits high heat conductivity as described above, and compared with conventional heat conductive sheets and non-curable or curable heat conductive greases. Thus, the remarkably excellent action and effect of having more excellent heat dissipation characteristics are exhibited. Even when the semiconductor device is continuously operated and used for a long period of time, the path made of gallium and / or gallium alloy and silver powder contained in the thermally conductive layer and forming the path is a cured product. Since it is fixed and held in the three-dimensional crosslinked network, it does not leak from the heat conductive layer.

  Furthermore, this heat conductive layer has tackiness and has a stable flexibility even when the heat radiating member is displaced, or even when used for a long time, from the heat generating electronic component and the heat radiating member. It will not peel off.

  It is also possible to prepare a sheet-like cured product having a desired thickness from the composition of the present invention in advance and interpose it between the heat-generating electronic component and the heat-dissipating member in the same manner as a conventional heat-conductive sheet. Effects can be obtained. In addition, a sheet of a cured product of the composition of the present invention can be used as appropriate as a part of another device or the like that requires thermal conductivity and heat resistance.

  EXAMPLES Hereinafter, although an Example is hung up and this invention is further explained in full detail, this invention is not limited by this.

The components (A) to (H) used in the following examples and comparative examples are shown below.
(A) component:
A dimethylpolysiloxane having a viscosity at 25 ° C. as shown below and having both ends blocked with dimethylvinylsilyl groups;
(A-1) Viscosity: 0.6 Pa · s
(A-2) Viscosity: 3.0 Pa · s
(A-3) Viscosity: 10.0 Pa · s
(A-4) Viscosity: 30.0 Pa · s

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

Component (C):
(C-1) Metallic gallium [melting point = 29.8 ° C.]
(C-2) Ga-In alloy
[Mass ratio = 75.4: 24.6, melting point = 15.7 ° C.]
(C-3) Ga-In-Bi-Sn alloy
[Mass ratio = 9.4: 47.3: 24.7: 18.6, melting point = 48.0 ° C.]
(C-4) Metal indium [melting point = 156.2 ° C.] <For comparison>

(D) Component (D-1): Silver powder [Average particle diameter: 7.3 μm]
(D-2): Silver powder [Average particle diameter: 25.2 μm]
(D-3): Silver powder [Average particle diameter: 105 μm] <For comparison>
(E) component:
(E-1): Alumina powder [Average particle size: 8.2 μm]
(E-2): Boron nitride powder [average particle size: 15.3 μm]

(F) component:
Dimethylpolysiloxane of platinum-divinyltetramethyldisiloxane complex (both ends are blocked with dimethylvinylsilyl groups, viscosity: 0.6 Pa · s) solution [platinum atom content: 1% by mass]
(G) component:
(G-1) 50% by mass toluene solution of 1-ethynyl-1-cyclohexanol (H) Component:
(H-1) Structural formula: Organosilane represented by C ₁₀ H ₂₁ Si (OCH ₃ ) ₃ (H-2) The following structural formula:

で表される片末端トリメトキシシリル基封鎖ジメチルポリシロキサン

One-terminal trimethoxysilyl-blocked dimethylpolysiloxane represented by

[Examples 1-12, Comparative Examples 1-7]
<Preparation of composition>
Using the components having the compositions and amounts described in Tables 1 to 3, compositions were prepared as follows.
(A) component, (C) component, optionally (E) component and optionally (H) component are added to a conditioning mixer (made by Shinky Co., Ltd., trade name: Nertaro Awatori) with an internal volume of 250 ml. The temperature was raised to 0 ° C. and the temperature was maintained, and kneading was performed for 5 minutes. Next, kneading was stopped and cooled to 15 ° C. or lower.

Next, (B) component, (D) component, (F) component, and (G) component were added, the said each temperature was maintained, and it knead | mixed so that it might become uniform, and prepared each composition.
The viscosity (Pa · s) of each composition thus obtained at 25 ° C. was measured using a Malcolm viscometer (Malcom Co., Ltd., model: PC-1T). The measurement results are shown in Tables 1 to 3.

<Preparation of cured product>
Each composition obtained above was applied to the entire surface of an aluminum plate (hereinafter referred to as a “standard aluminum plate”) having a diameter of 1.26 mm and a thickness of 1 mm, and another standard aluminum plate was stacked thereon to obtain about 175.5 kPa. A three-layer structure was obtained by applying a pressure of (1.80 kgf / cm ² ). Next, the temperature was raised to 125 ° C. in an electric furnace and the temperature was maintained for 1 hour to cure each composition, and then allowed to cool to room temperature to prepare a sample for measuring thermal resistance.

  The thickness of each cured sample was measured, and the thickness of each cured composition was calculated by subtracting the known thickness of the standard aluminum plate. Note that a micrometer (Mitutoyo Corporation, model; M820-25VA) was used for measuring the thickness of each sample. Tables 1 to 3 show the thickness of each cured composition.

<Measurement of thermal resistance>
Using each of the above samples, the thermal resistance (mm ² -K / W) of each cured composition was measured using a thermal resistance measuring instrument (Microflash manufactured by Holometrix). The measurement results are shown in Tables 1 to 3.

<Application to semiconductor devices>
0.2 g of the composition obtained in each of the above Examples 1 to 12 was applied to the surface of a 2 cm × 2 cm CPU to form a coating layer. The heat radiating member is stacked on the coating layer, and pressed and cured in the same manner as in the preparation of the cured product, so that the CPU and the heat radiating member are joined via a heat conductive layer having a thickness of 30 to 70 μm. A semiconductor device was obtained. When these devices were installed and operated in a host computer, personal computer, etc., the heat generation temperature of the CPU was about 100 ° C, but in any case, stable heat conduction and heat dissipation are possible for a long time. Yes, it was possible to prevent CPU performance degradation and damage due to overheat accumulation. Therefore, it was confirmed that the reliability of the semiconductor device was improved by employing the cured product of the composition of the present invention.

(note)
* SiH / Vi = the number of SiH in component (B) relative to one vinyl group in component (A) (hereinafter the same)

(Note) In either case, a grease-like uniform composition could not be obtained. Moreover, the composition layer could not be formed, and the thermal resistance could not be measured.

  The composition of the present invention is useful for conducting heat from a heat-generating electronic component such as a CPU to the heat radiating member to dissipate heat.

1. Curable composition layer (thermally conductive layer)
2. IC package3. 3. Printed wiring board 4. Heat dissipation member Clamp

Claims (8)

(A) Organopolysiloxane having two or more alkenyl groups bonded to silicon atoms in one molecule and having a viscosity at 25 ° C. of 0.05 to 100 Pa · s: 100 parts by mass
(B) Organohydrogenpolysiloxane having two or more hydrogen atoms bonded to a silicon atom: One alkenyl group in the component (A) bonded to a silicon atom in the component An amount such that the number of hydrogen atoms is 0.1 to 5.0,
(C) Gallium and / or a gallium alloy having a melting point of 0 to 70 ° C.
(D) a silver powder having an average particle size of 0.1 to 100 μm,
The sum total of (C) component and (D) component is 300-5000 mass parts, and these are (C) component / {(C) component + (D) component)} = 0.1-0.9 in mass ratio. It is.
(E) Thermally conductive filler having an average particle diameter of 0.1 to 100 μm other than silver: 0 to 1000 parts by mass,
(F) Platinum-based catalyst: effective amount, and (G) addition reaction control agent: a curable, grease-like thermally conductive silicone composition containing an effective amount. Furthermore, (H-1) the following general formula (1):
R ¹ _a R ² _b Si (OR ³ ) _4-ab (1)
Wherein R ¹ is independently an alkyl group having 6 to 15 carbon atoms, R ² is independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms, and R ³ is independently Is an alkyl group having 1 to 6 carbon atoms, a is an integer of 1 to 3, b is an integer of 0 to 2, and the sum of a + b is an integer of 1 to 3.)
The heat conductive silicone composition of Claim 1 containing 0-20 mass parts of alkoxysilane compounds represented by these. Furthermore, (H-2) the following general formula (2):

(2)
(In the formula, R ³ is independently an alkyl group having 1 to 6 carbon atoms, and c is an integer of 5 to 100.)
The heat conductive silicone composition of Claim 1 or 2 containing 0-100 mass parts of dimethylpolysiloxane by which one terminal of the molecular chain represented by this was blocked with the trialkoxy silyl group. It is a manufacturing method of the composition of any one of Claims 1-3, Comprising:
(i) the component (A), the component (C), the component (E), the component (H-1), the component (H-1), and the component (H-2) C) a step of kneading at a temperature equal to or higher than the melting point of the component to obtain a uniform mixture;
(ii) stopping kneading and cooling the temperature to below the melting point of the component (C); and
(iii) The component (D), the component (B), the component (F), the component (G), and optionally other components are added, and the temperature below the melting point of the component (C) The manufacturing method including the process of knead | mixing and obtaining a uniform mixture.   The heat conductive hardened | cured material obtained by processing the composition of any one of Claims 1-3 at 80-180 degreeC.   Use of the thermally conductive cured product according to claim 5 as a thermally conductive layer disposed between a heat generating electronic component and a heat radiating member.   A semiconductor device comprising a heat-generating electronic component, a heat dissipation member, and a thermally conductive layer made of a cured product of the composition according to claim 1, wherein the heat-generating electron A semiconductor device in which a component and the heat dissipating member are joined via the thermally conductive layer. A method of manufacturing a semiconductor device according to claim 7,
(a) applying the composition to the surface of the exothermic electronic component to form a coating layer made of the composition on the surface;
(b) a step of pressing and fixing the heat radiating member to the coating layer; and
(c) The manufacturing method including the process of processing the obtained structure at 80-180 degreeC, hardening the said coating layer, and setting it as the said heat conductive layer.

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