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Circuit Module With Improved Thermal Conductivity Between Separable Parts With Intervening Electrical Insulation

IP.com Disclosure Number: IPCOM000040285D
Original Publication Date: 1987-Oct-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Eid, JC: AUTHOR [+3]

Abstract

Some circuit modules have a metal heat transfer structure that must be attached to a metal structure that supports the electrical components of the module. The heat transfer structure must be electrically insulated from the component supporting structure, but there must be good heat transfer between the structures. A layer of an electrically insulating material, such as alumina, is formed on the contacting surface of one of the structures, and a layer of a first metal is formed over the insulating layer. The metal layer is electrically isolated from the underlying metal structure. A layer of a second metal is formed on the contacting surface of the other structure. The layer of electrical insulation resents a high thermal resistance that is not changed by the overlying metal layer.

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Circuit Module With Improved Thermal Conductivity Between Separable Parts With Intervening Electrical Insulation

Some circuit modules have a metal heat transfer structure that must be attached to a metal structure that supports the electrical components of the module. The heat transfer structure must be electrically insulated from the component supporting structure, but there must be good heat transfer between the structures. A layer of an electrically insulating material, such as alumina, is formed on the contacting surface of one of the structures, and a layer of a first metal is formed over the insulating layer. The metal layer is electrically isolated from the underlying metal structure. A layer of a second metal is formed on the contacting surface of the other structure. The layer of electrical insulation resents a high thermal resistance that is not changed by the overlying metal layer. However, the temperature drop across the alumina layer is held to a minimum value because the overlying metal layer makes the heat flux more uniform in the alumina layer. Heat flux is unevenly distributed near the surface because the surfaces contact only at local areas. Heat flux is concentrated where heat flows through the contact points. In structures where this contact occurs at a surface of alumina, the poor thermal conductivity of the alumina causes high concentrations of heat flux throughout the alumina layer and thereby raises the temperature drop across the alumina...