Browse Prior Art Database

Edge Mounted MLC Packaging Scheme

IP.com Disclosure Number: IPCOM000052286D
Original Publication Date: 1981-May-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 3 page(s) / 90K

Publishing Venue

IBM

Related People

Gegenwarth, RE: AUTHOR [+3]

Abstract

For greater cooling capacity, higher density or increased wiring flexibility, it is often advantageous to run electrical circuitry on orthogonal planes in either a monolithic structure or by connecting separate parts with pins, leads, solder connections, etc. Ideally, for structural strength, the parts should be mechanically fastened as well as electrically connected.

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Edge Mounted MLC Packaging Scheme

For greater cooling capacity, higher density or increased wiring flexibility, it is often advantageous to run electrical circuitry on orthogonal planes in either a monolithic structure or by connecting separate parts with pins, leads, solder connections, etc. Ideally, for structural strength, the parts should be mechanically fastened as well as electrically connected.

A method for vertical chip packaging is outlined in the IBM Technical Disclosure Bulletin 20 11A, 4339-4340 (April 1978) in which memory chips are vertically mounted. Electrical connections to surface metallurgy provide bonding of parts. In the present approach, ceramic parts would be bonded with surfaces at right angles, but a method is described for making connections to metallurgy on any plane at its edge. This would provide for electrical connections to internal wiring planes at any depth in multilayer ceramic (MLC) substrates, without the need to bring the wiring through the outer layer to the top or bottom surface. This approach should allow mechanical bonding as well as electrical connection. Techniques used in MLC fabrication could be used as follows: 1) Punch a ceramic green sheet 10 to form via holes 12. Additional holes 14 would be provided around the perimeter at points where edge connections are desired (Fig. 1), as well as holes for alignment pins. 2) Screen metallurgy patterns on surface and all holes with Cu paste 12' and 14'. 3) Stack and laminate a plurality of green sheets. 4) Trim edges of laminate to expose edge vias 14' (Fig. 2, where only one layer is shown for clarity). 5) Heat-treat for nucleation, sintering and crystallization of ceramic. 6) If necessary, after densification (step 5) the edges of the MLC may be polished, etc.,...