Browse Prior Art Database

Method of Bonding Chip Carrier to Cryogenic Heat Sink

IP.com Disclosure Number: IPCOM000036662D
Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Schwall, RE: AUTHOR

Abstract

Disclosed is a method of bonding a semiconductor chip or semiconductor chip carrier to a low temperature cooled surface or coldhead.

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Method of Bonding Chip Carrier to Cryogenic Heat Sink

Disclosed is a method of bonding a semiconductor chip or semiconductor chip carrier to a low temperature cooled surface or coldhead.

An array of metal structures (dots, lines or polygons) fabricated from a metal (such as indium) which retains its ductility at cryogenic temperatures is deposited on the face of the structure to be cooled. This metal array is then warm- or cold- bonded to a cryogenic heat sink. The thermal conductance of the interface is proportional to the total area of the metal bond, but the sheer strength of the bond and resultant stress on the semiconductor chip or chip carrier is dependent on the subdivision of the metal. If the metal is subdivided so that the width of a feature is small compared to its thickness, the bond behaves mechanically like a simple beam, possessing significantly more flexibility than a continuous sheet of metal. In practice, only a moderate degree of subdivision is required to achieve the desired mechanical and thermal performance. The preferred approach minimizes the dimension of the metal structure in the direction of maximum differential thermal contraction. A single chip, for example, is effectively cooled using an array of concentric circles deposited about the chip center.

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