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Browse Prior Art Database

Thermal Grease Module Cap Design

IP.com Disclosure Number: IPCOM000061635D
Original Publication Date: 1986-Sep-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Andros, FE: AUTHOR [+4]

Abstract

An integrated circuit module includes a cap 10 with sidewalls 11 bonded by seal agent 12 to the outer edges of a ceramic substrate 13. Cap 10 has a heat sink 14 bonded by thermal grease 15 to a semiconductor chip 16 attached to the substrate by solder joints 17. The cap 10 is designed to permit flexure of the sidewalls 11 caused by thermal mismatch between the metal cap 10 and the ceramic substrate 13 to occur without causing excess bowing of the cap in the heat sink area which causes stress cracks in the solder joints 17. Basically the cap is designed so that the heat sink region is relatively thick compared to the sidewalls so that flexure occurs primarily in the sidewalls or at the point of connection to the heat sink region. As shown in Fig. 1, cap 10 is formed with a deep groove 18 between sidewall 11 and heat sink 14.

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Thermal Grease Module Cap Design

An integrated circuit module includes a cap 10 with sidewalls 11 bonded by seal agent 12 to the outer edges of a ceramic substrate 13. Cap 10 has a heat sink 14 bonded by thermal grease 15 to a semiconductor chip 16 attached to the substrate by solder joints 17. The cap 10 is designed to permit flexure of the sidewalls 11 caused by thermal mismatch between the metal cap 10 and the ceramic substrate 13 to occur without causing excess bowing of the cap in the heat sink area which causes stress cracks in the solder joints 17. Basically the cap is designed so that the heat sink region is relatively thick compared to the sidewalls so that flexure occurs primarily in the sidewalls or at the point of connection to the heat sink region. As shown in Fig. 1, cap 10 is formed with a deep groove 18 between sidewall 11 and heat sink 14. Groove 18 allows flexure in the region outside groove 18 without producing bowing which causes the heat sink 14 to apply compression or tension stresses on the joints 17. Figs. 2 - 4 show caps with stepped construction between sidewalls 11 and heat sink 14. The intermediate stepped regions 19 reduce bowing of the cap in the region of the heat sink 14. In the cap structure of Fig. 3 the groove 18 is extremely thin, reducing bowing of the cap. In the cap structures of Fig. 4, the sidewalls 11 are made very thin so that flexure occurs mainly in the sidewall 11. In Fig. 5, the sidewall 11 is thicker but the interme...