Browse Prior Art Database

High I/O Hermetic Interconnect for Aluminum Modules

IP.com Disclosure Number: IPCOM000109453D
Original Publication Date: 1992-Aug-01
Included in the Prior Art Database: 2005-Mar-24
Document File: 1 page(s) / 58K

Publishing Venue

IBM

Related People

Lake, JK: AUTHOR [+4]

Abstract

Disclosed is a design that allows a multi-layer ceramic (MLC) high input-output (I/O) electrical feed through structure inserted through the sidewall of an aluminum Hybrid Circuit Module to be hermetically sealed. This design overcomes stress problems created when a material with low Co-efficient of Thermal Expansion (CTE) such as an alumina ceramic is attached to a high CTE material such as aluminum.

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High I/O Hermetic Interconnect for Aluminum Modules

      Disclosed is a design that allows a multi-layer ceramic (MLC)
high input-output (I/O) electrical feed through structure inserted
through the sidewall of an aluminum Hybrid Circuit Module to be
hermetically sealed.  This design overcomes stress problems created
when a material with low Co-efficient of Thermal Expansion (CTE) such
as an alumina ceramic is attached to a high CTE material such as
aluminum.

      In this design, the aluminum wall of the module chassis is
slotted, and a specially designed end plate is welded or brazed in
place over the slot.  The plate is fabricated from a sheet of
aluminum with a layer of ASTM F15 alloy (Kovar*) explosively clad to
its surface.  As shown in the figure, the Kovar at the perimeter of
the plate is machined away leaving an aluminum flange, while at the
center of the plate, the aluminum is machined away leaving only the
Kovar.  A slot is milled in the Kovar (*Trademark of Carpenter
Technology Co.) center section to accommodate the ceramic I/O feed
through.

      The aluminum flange provides a surface sufficient for brazing
or welding directly to the aluminum module chassis with no
stress-producing mismatch in CTE.  After surface treating the Kovar
center section to improve solderability, the I/O feed through is
aligned and solder sealed in place.  The CTE of Kovar is a good match
to that of the alumina ceramic, thus a low stress hermetic seal is
produced. ...