Conformal thermal interface material for electronic components

Abstract

A thermally-conductive interface for conductively cooling a heat-generating electronic component having an associated thermal dissipation member such as a heat sink. The interface is formed as a self-supporting layer of a thermally-conductive material which is form-stable at normal room temperature in a first phase and substantially conformable in a second phase to the interface surfaces of the electronic component and thermal dissipation member. The material has a transition temperature from the first phase to the second phase which is within the operating temperature range of the electronic component.

Description

[0001] This application is a continuation of U.S. patent application Ser. No. 09 / 714,680, filed Nov. 16, 2000; which is an application for reissue of U.S. patent application Ser. No. 08 / 801,047, filed Feb. 14, 1997, now U.S. Pat. No. 6,054,198, granted Apr. 25, 2000, the disclosure of each of which is expressly incorporated herein by reference.[0002] The present invention relates broadly to a heat transfer material which is interposable between the thermal interfaces of a heat-generating, electronic component and a thermal dissipation member, such as a heat sink or circuit board, for the conductive cooling of the electronic component. More particularly, the invention relates to a self-supporting, form-stable film which melts or softens at a temperature or range within the operating temperature range of the electronic component to better conform to the thermal interfaces for improved heat transfer from the electronic component to the thermal dissipation member.[0003] Circuit designs ...

AI Technical Summary

Benefits of technology

The film provides efficient heat transfer by filling interface irregularities and eliminating air pockets, allowing for automated application and reduced manufacturing costs while maintaining ease of handling.

Problems solved by technology

Circuit designs for modern electronic devices such as televisions, radios, computers, medical instruments, business machines, communications equipment, and the like have become increasingly complex.

Although the complexity of the designs has increased, the size of the devices has continued to shrink with improvements in the ability to manufacture smaller electronic components and to pack more of these components in an ever smaller area.

As electronic components have become smaller and more densely packed on integrated boards and chips, designers and manufacturers now are faced with the challenge of how to dissipate the heat which is ohmicly or otherwise generated by these components.

Indeed, it is well known that many electronic components, and especially semiconductor components such as transistors and microprocessors, are more prone to failure or malfunction at high temperatures.

Thus, the ability to dissipate heat often is a limiting factor on the performance of the component.

For high power circuits and the smaller but more densely packed circuits typical of current electronic designs, however, simple air circulation often has been found to be insufficient to adequately cool the circuit components.

However, and as is described in U.S. Pat. No. 4,869,954, the faying thermal interface surfaces of the component and heat sink typically are irregular, either on a gross or a microscopic scale.

These pockets reduce the overall surface area contact within the interface which, in turn, reduces the efficiency of the heat transfer therethrough.

Moreover, as it is well known that air is a relatively poor thermal conductor, the presence of air pockets within the interface reduces the rate of thermal transfer through the interface.

The greases and waxes of the aforementioned types heretofore known in the art, however, generally are not self-supporting or otherwise form stable at room temperature and are considered to be messy to apply to the interface surface of the heat sink or electronic component.

Moreover, use of such materials typically involves hand application or lay-up by the electronics assembler which increases manufacturing costs.

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