Browse Prior Art Database

Thermally Enhanced Single Chip Module

IP.com Disclosure Number: IPCOM000051958D
Original Publication Date: 1981-Apr-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Goldmann, LS: AUTHOR

Abstract

A number of semiconductor packaging designs [*] use thermal grease to transfer heat from chip to (alumina) cap, solder seal, and standoffs in the preform to maintain separation. The underside of the hat is ground to insure the distance 6, as in Fig. 1A. During assembly, a load is applied to the hat to insure leveling (Fig. 1B).

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Thermally Enhanced Single Chip Module

A number of semiconductor packaging designs [*] use thermal grease to transfer heat from chip to (alumina) cap, solder seal, and standoffs in the preform to maintain separation. The underside of the hat is ground to insure the distance 6, as in Fig. 1A. During assembly, a load is applied to the hat to insure leveling (Fig. 1B).

Although this package (in single-chip form) has desirable heat transfer capability, the proposed modification further enhances this package in the design of Figs. 2A and 2B. This modification adds a punched or coined copper washer which sits on the substrate, surrounding the chip, and acts both as a standoff and parallel heat path.

The advantages are:
1. Thermal enhancement provided by the path from

multilayer ceramic (MLC) substrate (s/s) to the cap.

(Further enhancement is possible by a thin grease layer

between the washer and cap, or the washer and s/s.)
2. Cost reduction. Elimination of most of the cap

waviness from grease thickness tolerance could obviate

the need to grind the cap. Washer is inexpensive and

can be easily held to tight tolerances.
3. Eliminates potential problem of copper ball standoffs

collapsing under assembly frame.

References * ] A. J. Arnold and U. P. Hwang, "Thermally Enhanced Module for Self-Contained Data Processing Package," IBM Technical

Disclosure Bulletin 20, 1766-1777 (October 1977); A. J.

Arnold, G. J. Robbins and M. J. Siwy, Jr., "Two-Stage

Module Seal," IBM Technica...