JPH1167992A - Heat-radiation spacer and heat-radiation component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-radiation spacer with which ideal heat-radiation can be conducted even with a warped exothermic electronic component. SOLUTION: This heat-radiation spacer is of a silicon solidified material of asker C hardness 60 or lower which comprises a thermal-conductive filler, its surface is formed into a convex surface especially with at least one groove, a depth of 0.1 mm or more and width of 0.3 mm or more, provided on the convex surface. In addition, the heat-radiation spacer is laminated on a heat- radiation fin or a metal plate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat radiating spacer and a heat radiating component which have high flexibility and reduce a load on a heating element when incorporated in an electronic device.

[0002]

2. Description of the Related Art In heat-generating electronic components such as transistors and thyristors, it is important to remove heat generated during use. Heretofore, as a heat removal method, it has been general to attach a heat-generating electronic component to a radiating fin or a metal plate via an electrically insulating heat conductive sheet. As such a heat conductive sheet, a heat radiating sheet in which a silicone rubber is filled with a heat conductive filler is mainly used.

On the other hand, with the recent increase in the density of electronic devices,
The amount of heat generated from the LSI used in the CPU has also been increasing, and in this case, a method of transferring heat to the heat radiation fins via a flexible heat radiation spacer on the upper part of the CPU has been generally adopted. As the heat dissipation spacer, a liquid silicone rubber solidified material is filled with a thermally conductive insulating inorganic powder such as alumina and boron nitride powder,
Those having Asker C hardness of about 60 or less are used.

[0004]

However, the surface shape of the conventional heat-radiating spacer is not so much a problem based on the idea that its flexibility can easily follow the unevenness of the heat-generating electronic component. Had a flat surface. For this reason, if the heat-generating electronic component has warpage, the adhesion becomes insufficient, not only the heat transfer property of the heat radiation spacer is not effectively exerted, but also air is sealed between the heat-generating electronic component and the like. There was a problem that ideal heat transfer was not performed.

The present invention has been made in view of the above, and an object of the present invention is to provide a heat-dissipating spacer capable of ideally dissipating heat even when a heat-generating electronic component having a warp is used. .

[0006]

That is, the present invention provides a silicone solidified product having a Asker C hardness of 60 or less containing a thermally conductive filler, the surface of which is formed as a convex surface. In particular, the heat radiation spacer is characterized in that at least one groove having a depth of 0.1 mm or more and a width of 0.3 mm or more is provided on the convex surface. Further, the present invention is a heat dissipating component, wherein the heat dissipating spacer is laminated on a heat dissipating fin or a metal plate.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail.

The heat radiation spacer of the present invention is obtained by adding a heat conductive filler to a solidified silicone material. The solidified silicone has high flexibility, and a solidified addition reaction type liquid silicone is used.
Specific examples of the addition-reaction-type liquid silicone include a one-pack silicone having both a vinyl group and an H-Si group in one molecule, or an organopolysiloxane having a vinyl group in a terminal or a side chain and a terminal or side chain. A two-part silicone with an organopolysiloxane having two or more H-Si groups in the chain can be used. As a commercially available product of such an addition reaction type liquid silicone, for example, a product name “SE-1885A / B” manufactured by Toray Dow Corning Co., Ltd.
And the like. The flexibility of the heat radiation spacer can be adjusted by the crosslink density formed by the addition reaction or the amount of the thermally conductive filler.

The heat conductive filler imparts heat conductivity to the heat radiating spacer, and the heat conductivity is controlled by the type and amount of the heat conductive filler. As the heat conductive filler, for example, when insulation is required, boron nitride, silicon nitride, aluminum nitride, alumina, magnesia, silicon carbide, and the like, and when insulation is not required, aluminum, copper, silver, and the like are selected. One or two or more are used. The shape of the heat conductive filler may be spherical, powdery, fibrous, needle-like, scale-like, or the like, and its particle size is about 1 to 100 μm in average particle size.

The heat conductive filler suitable for the present invention is preferably filled with a large amount of boron nitride from the viewpoint of heat conductivity because high heat conductivity can be obtained at the same filling rate. Alternatively, it is preferable to use boron nitride in combination with alumina or magnesia because soft silicone solidified product can be obtained at the same filling ratio when magnesia is filled.

The content of the heat conductive filler varies depending on the kind of the heat conductive filler.
It is desirably about 70 to 70% by volume, preferably 30 to 60% by volume. If it is less than 20% by volume, thermal conductivity is not sufficient, and if it exceeds 70% by volume, the flexibility as a heat radiation spacer is lost, which is not preferable.

The thermal conductivity of the heat radiation spacer of the present invention is:
It is preferably 0.8 W / m · K or more, particularly preferably 1.5 W / m · K or more. The Asker C hardness is preferably 60 or less.

The heat radiation spacer of the present invention has the above characteristics, and is characterized in that its surface is made convex. Preferably, a gentle convex surface is formed from the end to the central portion of the heat radiation spacer, and the maximum thickness of the central portion of the convex surface is 1/10 or more of the thickness of the heat radiation spacer (thickness of the end of the heat radiation spacer), particularly 2 / Preferably, the thickness is 10 to 1/1 thicker. If the maximum thickness of the central portion of the convex surface is less than 1/10 of the thickness of the heat radiation spacer, the shape followability and the effect of preventing air entrapment become insufficient, and if it exceeds 1/1, the contact area may be reduced. . The thickness of the heat radiation spacer (the thickness of the end of the heat radiation spacer) is 0.2 to 10 mm, particularly 0.5 to 2 mm.
It is preferred that

In the heat radiation spacer of the present invention, a groove having a width of 0.3 mm or more and a depth of 0.1 mm or more is formed on its convex surface.
By providing at least one groove, preferably two or more in a cross, preferably having a width of 0.5 to 2 mm and a depth of 0.3 to 1 mm, it is possible to prevent the trapped air from being trapped.

An example of the method for producing the heat radiation spacer of the present invention is as follows. One-part silicone or organopolysiloxane having a vinyl group at a terminal or side chain and two or more H-Si compounds at a terminal or side chain are shown. A slurry is prepared by mixing a two-part silicone with a group-containing organopolysiloxane and a thermally conductive filler, and then the slurry is poured onto a radiation fin on which a release mold made of a fluororesin or the like is placed.

At this time, in order to form a convex surface on the surface of the heat radiating spacer, a release mold having a raised central portion is used. The high viscosity slurry is poured into the central portion of the mold and allowed to flow naturally.
It can be performed by a method such as pouring a plurality of times only into the center of the mold.

Next, the silicone is solidified by heating in a drier, and after cooling, the mold is removed, so that a radiating fin with a radiating spacer can be manufactured. If the heat radiation fins are also removed, only the heat radiation spacer is used. If necessary,
Further, heat treatment may be performed.

Further, the heat radiation spacer of the present invention is obtained by laminating one or more of the heat radiation spacers on one or both surfaces of a metal plate or a heat radiation fin to form a heat radiation component. In stacking, for example, one or two or more heat radiating spacers having different sizes or the same size may be arranged on part or all of the front surface or the back surface of the metal plate and stacked.
Further, a plurality of heat radiation spacers may be laminated at equal intervals or at arbitrary intervals in a U-shape along the edge surface of three of the four sides of the heat radiation fin or the metal plate.

As the radiation fin or the metal plate, for example, aluminum, copper, iron, stainless steel, enamel and the like are used, and aluminum is particularly preferable.

The heat radiating component of the present invention has good handleability,
It can be used by directly attaching to a circuit board on which heat-generating electronic components are mounted.

[0021]

The present invention will be described more specifically with reference to examples and comparative examples.

Examples 1-3 Liquid A (organopolysiloxane having a vinyl group) and B
Table 1 shows the mixing ratio of the two-component addition reaction type silicone (trade name “SE-1885” manufactured by Toray Dow Corning Co., Ltd.) of the liquid (organopolysiloxane having an H—Si group) to the liquid A and the liquid B. The mixture was blended (volume%) and mixed with alumina powder having an average particle diameter of 17 μm (trade name “AS” manufactured by Showa Denko KK).
-30 "), boron nitride powder having an average particle diameter of 15 μm (trade name" DENCABORON NITRIDE "manufactured by Denki Kagaku Kogyo Co., Ltd.)
And silicon nitride powder having an average particle diameter of 28 μm (trade name “Denka Silicon Nitride” manufactured by Denki Kagaku Kogyo Co., Ltd.) at a ratio (volume%) shown in Table 1 to obtain a compound (viscosity: about 80,0).
00-120,000 cps).

This compound is used as a heat radiation fin (trade name "High Power Heat Sink / 85BS1" manufactured by Ryosan Co., Ltd.).
11 ") was filled in a predetermined amount, and a fluororesin mold having various sizes of recesses of 0.1 to 0.3 mm was pressed to form convex surfaces, and the thickness was as shown in Table 1.

Then, it was placed in a dryer and heated at 90 ° C. for 1 hour to solidify the silicone, the mold was removed, and further heated at 150 ° C. for 24 hours to obtain a heat radiation spacer.

Example 4 A heat radiation spacer was manufactured in the same manner as in Example 1, except that a groove having a width of 0.5 mm and a depth of 0.5 mm was provided in a cross shape on the convex surface of the heat radiation spacer. .

Comparative Examples 1-3 Liquids A (organopolysiloxane having a vinyl group) and B
A liquid (organic polysiloxane having an H-Si group) two-component addition reaction type silicone (trade name "SE-1885" manufactured by Dow Corning Toray Co., Ltd.) was mixed at a ratio shown in Table 1 to flatten the surface. Except for the manufacturing, a heat radiation spacer was manufactured in the same manner as in Example 1.

The hardness and thermal resistance of the heat-dissipating spacer produced above were measured as follows. Table 1 shows the results.

(1) Hardness Using the same slurry, a sample of 50 × 50 × 10 mm was manufactured and measured with an Asker C hardness meter.

(2) Thermal resistance A heat-dissipating spacer is sandwiched between the heater case and the copper plate, a load of 30 kg is applied to the heater case, and the heater case is applied with power of 20 W and held for 4 minutes. Measure the temperature difference (° C) and determine the thermal resistance (° C /
w) = thermal resistance (° C / ° C) by temperature difference (° C) / power (w)
W) was calculated.

[0030]

[Table 1]

From Table 1, it can be seen that the heat radiation spacer of the present invention has excellent Asker C hardness of 60 or less and is excellent in flexibility, and the filling amount of the heat conductive filler is equal to that of the comparative example. Since the thermal resistance is small despite its thickness, efficient heat radiation can be performed while maintaining good adhesion.

[0032]

The heat radiating spacer of the present invention has excellent flexibility and thermal conductivity, and has good adhesiveness not only when the heat-generating electronic component does not have warpage but also when it has warpage. In this state, efficient heat radiation can be performed.

Claims (3)

[Claims] 1. A heat-dissipating spacer, which is a solidified silicone material having a Asker C hardness of 60 or less containing a thermally conductive filler, the surface of which is formed as a convex surface. 2. The convex surface has a depth of 0.1 mm or more and a width of 0.3 mm.
The heat radiation spacer according to claim 1, wherein at least one groove having a diameter of at least one mm is provided. 3. A heat dissipating component comprising the heat dissipating spacer according to claim 1 laminated on a heat dissipating fin or a metal plate.