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Process for Removing Some Thermally Conductive Adhesive Films from Chips After Heat Sinks Had Been Attached

IP.com Disclosure Number: IPCOM000038147D
Original Publication Date: 1989-Nov-01
Included in the Prior Art Database: 2005-Jan-31
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Edwards, DL: AUTHOR [+2]

Abstract

Semiconductor chips 1 are often cooled by the attachment of heat sinks 2 to the backs of the chips. It is often desirable to be able to completely remove the heat sink and adhesive that was either permanently or temporarily attached. This disclosure solves the problems of having a procedure for the complete removal of some adhesives used for heat sink attachment, from the damage or contaminate semiconductor packages.

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Process for Removing Some Thermally Conductive Adhesive Films from Chips After Heat Sinks Had Been Attached

Semiconductor chips 1 are often cooled by the attachment of heat sinks 2 to the backs of the chips. It is often desirable to be able to completely remove the heat sink and adhesive that was either permanently or temporarily attached. This disclosure solves the problems of having a procedure for the complete removal of some adhesives used for heat sink attachment, from the damage or contaminate semiconductor packages.

The film adhesive 3 used to attach heat sinks to the backs of the chips must have cohesive properties that are significantly stronger than its adhesive properties, so that it remains intact upon disassembly. The film is usually very thin to minimize the thermal resistance from the chip to the heat sink. The top surfaces of the chips are flat and have been polished to a mirror finish. The heat sinks 2 are also flat and polished so that the thermal resistance through the adhesive is minimized by minimizing the gap space between the chip and the heat sink. The heat sink also has small grooves 4 to provide extra surface area for the adhesive to bond to.

As shown in Figure 2, the adhesive 3 interlocks in the grooves 4 in the heat sink 2. To remove the heat sinks the assembly is heated, either in an oven or from the substrate side, and the heat sinks are torqued off. As shown in Figure 1, the grooves in the heat sinks are oriented radially, to act as...