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Protective Layer for Multilayer Ceramic I/O Pins

IP.com Disclosure Number: IPCOM000051957D
Original Publication Date: 1981-Apr-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Ricker, MW: AUTHOR [+2]

Abstract

Discussed is a technique for the reduction of MCM (multi-chip module) pin damage from thermal excursions or mechanical damage.

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Protective Layer for Multilayer Ceramic I/O Pins

Discussed is a technique for the reduction of MCM (multi-chip module) pin damage from thermal excursions or mechanical damage.

This technique comprises applying a layer of KEVLAR*/polymide- or KEVLAR/epoxy-coated laminate to the bottom (I/O) side of substrates after pins are joined.

The thermal expansion properties of the laminates can be matched to those of the Al(2)O(3) substrate. This layer would prevent mechanical and thermal damage during the processing and subsequent thermal cycle damage during machine use in the field.

The cured laminate would move the primary stress/strain point from the pin/braze connection to the stronger pin shank.

The KEVLAR pre-preg or laminate can be trimmed, and the pin holes opened with a laser. After applying the sheet to the substrate, a curing cycle allows the laminate/epoxy to flow and bond to the Al(2)O(3) surface and seal the pin/braze connection from external environments and stresses.

The KEVLAR laminate can be constructed in several ways. 1. Pre-pregnated sheets laid up to the required thickness and cured in place on the substrate. 2. A laminate of several KEVLAR layers with a layer of uncured epoxy on the substrate side. This type would handle easier handle easier and, cured in place, would allow the epoxy to fill in the pin holes, flow around the pin

Several types of pin holes can be obtained with the laser:

1. Oversized - to clear the entire pin/braze area.

2. Tapered -...