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Electrical Interconnect Structure for Laminate Assemblies

IP.com Disclosure Number: IPCOM000078193D
Original Publication Date: 1972-Nov-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 70K

Publishing Venue

IBM

Related People

Abolafia, OR: AUTHOR [+4]

Abstract

The fabrication of a multilayer circuit assembly is achieved by laminating subassemblies and joining the conductive elements from one subassembly to another, both electrically and mechanically, by application of a metal powder epoxy process at each joint interface.

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Electrical Interconnect Structure for Laminate Assemblies

The fabrication of a multilayer circuit assembly is achieved by laminating subassemblies and joining the conductive elements from one subassembly to another, both electrically and mechanically, by application of a metal powder epoxy process at each joint interface.

The figure shows an exploded view of a multilayer printed-circuit card assembly, including a plurality of printed-circuit cards 11a, 11b and 11c. Each printed-circuit card has a base of electric material. The desired configuration of printed circuit electrically conductive elements comprising conductive strips 12, circular connecting areas 13 and square connecting pads 14 may be affixed to one or both sides of the dielectric material. Apertures 15 in the order of o.010 inch or less are drilled into the printed circuit card layers. Apertures 15 are then metallically through plated to electrically interconnect the opposed pairs of circular areas 13. Via a mask, a thin layer (approx 0.0002 inch thick) of B-stage epoxy is applied to circuit areas 13 of the upper conductive surfaces of cards 11b and 11c. Uniformly spherical metal particulate powder 18 is then sprinkled over the entire surface. After moderate heating the powder particulate will remain only on the epoxied areas.

The lower surfaces of cards 11a and 11b are uniformly covered with a thin layer 17 of B-stage epoxy. ("B-stage" is a partial cure wherein the epoxy has a somewhat soft and stic...