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Epoxy/silicone Gel Dam for Packaging of Ceramic Chip Carriers

IP.com Disclosure Number: IPCOM000061375D
Original Publication Date: 1986-Jun-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 1 page(s) / 8K

Publishing Venue

IBM

Related People

Hoffman, PR: AUTHOR [+3]

Abstract

A fluorocarbon (e.g. Teflon) film tape with silicone or an acrylic pressure sensitive thermosetting adhesive is used to confine silicone gel and epoxy resin to the regions of the package desired. An application of the technique is described for a stacked package.

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Epoxy/silicone Gel Dam for Packaging of Ceramic Chip Carriers

A fluorocarbon (e.g. Teflon) film tape with silicone or an acrylic pressure sensitive thermosetting adhesive is used to confine silicone gel and epoxy resin to the regions of the package desired. An application of the technique is described for a stacked package.

The figure is a schematic drawing of a cross-section of a stacked package comprised of two ceramic circuit substrates 2 and 4 solder bonded to each other and with a silicon integrated circuit chip 6 solder bonded to the ceramic circuit substrate 4. The lower ceramic substrate 2 has connecting pins 8 extending beneath the package (many more than are shown). At this stage of the package assembly, a compliant roller is used to apply the film tape to the edges of the ceramic substrates 2 and 4, forming the dam around the substrates. Thus, a bond is formed between the pressure sensitive thermosetting adhesive on the tape and the ceramic substrate edges.

A silicone gel 12 is next applied and heat treated at gel temperature. The film tape 10 is not wet by the gel 12 and therefore contains the gel as shown. The aluminum cover 14 is then put in place, the package is inverted and the epoxy resin 16 is poured and heat cured. A good fill of epoxy resin 16 is obtained between the tape 10 and the aluminum 14 due to the wettability of aluminum by epoxy. The epoxy 16 will not go over the top of the tape at any point and will remain at a lower level (as shown)...