JPH0131299B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Background and Objectives of the Invention] The present invention relates to a ceramic substrate package that integrates a ceramic substrate on which a heat generating element is mounted and a heat sink.

Conventionally, epoxy resin with excellent thermal conductivity has been used to bond and integrate a heat sink and a ceramic substrate on which heat generating elements such as ICs and LSIs are mounted.

On the other hand, as electronic devices have become more dense and smaller in recent years, heat dissipation from heat-generating elements has become an important issue, and it is expected that rapid temperature changes will occur. When epoxy resin is used as an adhesive layer as in the past, the ceramic substrate, epoxy resin, and heat sink have different coefficients of thermal expansion, resulting in the problem of the adhesive layer being damaged under conditions of cooling/heating cycles or thermal shock. .

The present invention solves the above-mentioned problems of the prior art, and provides a ceramic substrate package that can prevent damage to the adhesive layer that integrates the ceramic substrate and the heat sink even under conditions involving rapid temperature changes. This is the purpose.

[Summary of the Invention] The present invention provides an adhesive layer that integrates a ceramic substrate on which a heat generating element is mounted and a heat dissipation body, formed of a thermally conductive composition containing an addition polymerizable silicone rubber and an inorganic filler. It is characterized by this.

In the present invention, the ceramic substrate may be made of a material with high thermal conductivity such as alumina, beryum oxide, boron nitride, or silicon carbide.

Heat generating elements mounted on ceramic substrates include ICs, LSIs, super LSIs, diodes, thyristors,
power transistors, etc.

As a heat sink, copper, copper alloy, aluminum,
It is generally made of metal such as iron, but it may also be made of ceramic.

The most important point in the present invention is that the adhesive layer for integrating the ceramic substrate and the heat sink is formed of a thermally conductive composition containing an addition polymerizable silicone rubber and an inorganic filler.

This composition has strong adhesion to both ceramics and metals, and has elasticity even after curing, so it can follow expansion and contraction caused by rapid temperature changes.

In addition, inorganic fillers are added to further improve the thermal conductivity of addition-polymerized silicone rubber, but since inorganic fillers have a smaller coefficient of thermal expansion than silicone rubber, It becomes possible to bring the coefficient of thermal expansion of the adhesive layer closer to that of the ceramic substrate and the heat sink, further increasing the ability to follow thermal shock.

The addition polymerizable silicone rubber in the present invention includes (1) diorganopolysiloxane having at least two silicon-bonded alkenyl groups in one molecule, (2) at least two silicon-bonded hydrogen atoms in one molecule. and (3) an addition reaction catalyst such as platinum or a platinum-based compound, which is crosslinked under the catalytic action of component (3) to form a rubber elastic body. It is. Such addition-polymerized silicone rubber is liquid before crosslinking and has excellent viscosity after crosslinking, and maintains excellent elasticity for a long period of time even when filled with inorganic fillers that increase thermal conductivity. It will be possible.

Examples of inorganic fillers include powders of alumina, quartz, zinc oxide, magnesia, boron nitride, aluminum nitride, silicon carbide, graphite, metals, etc., and these can be used alone or in combination of two or more.
It can be added in a range of ~70% by volume.

In the present invention, in addition to the above-mentioned components, reactive diluents, silicone oil, organic solvents, curing inhibitors such as benzotriazole and hydroperoxide to extend the pot life, and fumes are used to adjust the viscosity. Reinforcing fillers such as silica, colorants, flame retardants, etc. may be added as appropriate. Furthermore, the self-adhesiveness can be improved by adding a silane coupling agent, a titanate coupling agent, an epoxy resin, or the like.

A thermally conductive composition comprising the above components is inserted between the ceramic substrate and the heat sink, and then cured at room temperature or by heating to integrate the two.

[Embodiment of the Invention] The accompanying drawing shows a cross-sectional view of an embodiment of the ceramic substrate package of the present invention.

1 is a heat generating element, 2 is a ceramic substrate, 3 is a heat sink, 4 is an adhesive layer, 5 is a ceramic cap, 6
is the sealing glass.

Example 1 An LSI silicon element was used as the heat generating element 1, a silicon carbide substrate was used as the ceramic substrate 2, an aluminum fin was used as the heat sink 3, and a composition consisting of the following components (1) to (7) was inserted as the adhesive layer 4. The package was then formed by heating the entire package at 150° C. for 15 minutes.

(1) 100 parts by weight of dithylpolysiloxane with both ends blocked with dimethylvinylsilyl groups (2) 20 parts by weight of dimethylpolysiloxane (viscosity modifier) with both ends blocked with silanol groups (3) Methyl hydrogen polysiloxane with both ends blocked with trimethylsilyl groups Siloxane 12 parts by weight(4) Vinyltrimethoxysilane 2 parts by weight(5) Alumina 350 parts by weight(6) 1% by weight solution of chloroplatinic acid in isopropyl alcohol 1 part by weight(7) 30% by weight solution of benzotriazole in isopropyl alcohol 0.2 parts by weight The resulting package was subjected to a cycle test of 150°C for 30 minutes and -55°C for 30 minutes, repeated 100 times, and no abnormality was observed. Furthermore, the heat dissipation characteristics when the device was operated were good.

Example 2 A package was prepared in the same manner as in Example 1 except that an IC silicon element was used as the heat generating element 1, and the results were the same as in Example 1.

Example 3 A package was prepared in the same manner as in Example 1 except that 250 parts by weight of boron nitride was used instead of alumina in the composition forming the adhesive layer 4, but the results were the same as in Example 1. .

Comparative Example 1 A package was prepared in the same manner as in Example 1 except that the adhesive layer 4 was formed of a thermally conductive bisphenol epoxy resin.

When the same cycle test as in Example 1 was conducted, cracking or peeling occurred within 20 cycles.

Comparative Example 2 A package was produced in the same manner as in Example 1 except that alumina was not contained in the composition for forming the adhesive layer 4.

When the same cycle test as in Example 1 was conducted, no cracks were observed, but some peeling was observed.

Furthermore, it was confirmed that the heat dissipation characteristics when the device is operated are poor, shortening the lifespan of the device.

[Effects of the Invention] As explained above, the present invention provides a ceramic substrate package in which a ceramic substrate and a heat sink are integrated using a thermally conductive composition containing an addition-polymerized silicone rubber and an inorganic filler. This makes it possible to obtain a package that is sufficiently resistant to severe thermal shock.

Moreover, in the present invention, the thermal conductivity from the ceramic substrate to the heat sink is extremely good, making it possible to extend the life of the heat generating element.

[Brief explanation of drawings]

The accompanying drawings are cross-sectional explanatory views of one embodiment of the present invention. 1: Heat generating element, 2: Ceramic substrate, 3: Heat sink, 4: Adhesive layer.

Claims (1)

[Claims] 1. The ceramic substrate on which the exothermic element is mounted and the heat sink are made of diorganopolysiloxane having at least two silicon-bonded alkenyl groups in one molecule and at least two silicon-bonded hydrogen atoms in one molecule. What is claimed is: 1. A ceramic substrate package characterized in that liquid organopolysiloxane and a thermally conductive composition made of an addition-polymerizable silicone rubber made of an addition reaction catalyst mixed with an inorganic filler are integrated via an adhesive layer.