Browse Prior Art Database

Flexural Cap for Improved Integrated-Circuit Module Cooling

IP.com Disclosure Number: IPCOM000041383D
Original Publication Date: 1984-Jan-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Motschman, DR: AUTHOR [+2]

Abstract

A module cap with depressed grooves for moderate flexure provides a close tolerance heat conduction path to cool integrated-circuit chips. A module cap 1 (Fig. 1), fabricated by the sintered powder metal process of a low expansion alloy, is designed with grooves 2 radiating from the center to the edges. During the bonding operation, the cap is loaded at the center and edges, as shown by the heavy arrows in the cross section of Fig. 2, causing a flexure along the grooves, and bringing it to a close tolerance position relative to the substrate 3 and integrated-circuit chips 4. The cap center 5 post and edges are bonded into this position. The illustration shows a cap divided into eight sections. The flexure action effectively halves the camber or flatness tolerances along the edges and diagonals.

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Flexural Cap for Improved Integrated-Circuit Module Cooling

A module cap with depressed grooves for moderate flexure provides a close tolerance heat conduction path to cool integrated-circuit chips. A module cap 1 (Fig. 1), fabricated by the sintered powder metal process of a low expansion alloy, is designed with grooves 2 radiating from the center to the edges. During the bonding operation, the cap is loaded at the center and edges, as shown by the heavy arrows in the cross section of Fig. 2, causing a flexure along the grooves, and bringing it to a close tolerance position relative to the substrate 3 and integrated-circuit chips 4. The cap center 5 post and edges are bonded into this position. The illustration shows a cap divided into eight sections. The flexure action effectively halves the camber or flatness tolerances along the edges and diagonals. The gap between the chip and cap is filled with a thixotropic thermal joint compound 6 prior to bonding. This material has a relatively low thermal conductivity, therefore requiring the close chip-to-cap spacing for an effective thermal path. To accommodate a large module part number set of varying chip sizes, heights, and locations, a die insert is made up for each part number to fit with a general tool, thus eliminating the need to completely retool each cap part number. Heat sink segments 7 are mounted on the cap with an elastomer gasket 8 and clamp ring 9; their centers are held down by center screw 10 and was...