Browse Prior Art Database

Large Package for Hermetic Circuit Card Using Double Sided Explosion Clad Material

IP.com Disclosure Number: IPCOM000112458D
Original Publication Date: 1994-May-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 52K

Publishing Venue

IBM

Related People

Lake, JK: AUTHOR [+3]

Abstract

Disclosed herein is a design concept which provides a unique method for fabrication of a High Density Hermetic Card (HDHC) using double-sided explosion clad material.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 86% of the total text.

Large Package for Hermetic Circuit Card Using Double Sided Explosion
Clad Material

      Disclosed herein is a design concept which provides a unique
method for fabrication of a High Density Hermetic Card (HDHC) using
double-sided explosion clad material.

      As shown in the attached Figures, HDHC is a large hybrid
package enclosure designed to contain Printed Circuit Boards (PCB)
for high reliability applications requiring hermeticity.  Walls (A)
of low expansion ferrous alloys are brazed to the baseplate (B)
providing protective cavities for the PCB's which may be attached to
each side of the baseplate.  Signal Inputs and Outputs (I/O) are
transferred through the enclosure walls by means of ceramic
feed-throughs.  Hermeticity is achieved by solder sealing the
feed-throughs into slots (C) in the walls (A), and seam sealing
covers to the top surfaces of the walls to form separate hermetic
chambers on either side of the baseplate.  The low Coefficient of
Thermal Expansion (CTE) of the wall material is matched to that of
the ceramic feed-through and this low expansion alloy is readily
sealable using traditional seam sealing techniques.

      In the technique described here, two thick layers of the same
ferrous alloy material are explosion clad to a thin layer of
aluminum.  The ferrous material is machined away leaving only the
walls (B).

      This approach to the fabrication of the HDHC enclosure offers
the weight saving and excellent thermal proper...