Browse Prior Art Database

Picture Frame I/O Extension for MC Substrates

IP.com Disclosure Number: IPCOM000049298D
Original Publication Date: 1982-Apr-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 56K

Publishing Venue

IBM

Related People

Darrow, RE: AUTHOR [+2]

Abstract

A method is described for increasing the number of I/O pins on a metallized ceramic (MC) substrate without increasing the basic size of the substrate.

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Picture Frame I/O Extension for MC Substrates

A method is described for increasing the number of I/O pins on a metallized ceramic (MC) substrate without increasing the basic size of the substrate.

A standard substrate 1 can be designed to include solder pads 2 around the periphery of the substrate. Soldered to these pads are copper conductors 3 which bridge the gap between the MC substrate and a multilayer ceramic (MLC) picture frame 4 which surrounds the MC substrate. The MLC picture frame is mechanically attached to the MC substrate by using the last row of pins 5 to rivet the two together, or by adhesive bonding or other suitable means.

I/O pins 6 are brazed to the MLC picture frame, and these pins are electrically connected to solder pads 7 on the picture frame by internal circuitry 8 in the picture frame. The MLC solder pads 7 are electrically connected to the MC solder pads 2 by the copper conductors 3.

The present arrangement has the advantage that the thermal expansion of the ceramic MLC picture frame is the same as that of the ceramic MC substrate, and therefore no stresses are set up between the two parts or the solder joints which are used to connect the copper conductors 3.

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