Browse Prior Art Database

External Pre Lamination Via Connections in Multilayers

IP.com Disclosure Number: IPCOM000075778D
Original Publication Date: 1971-Nov-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Crimi, JS: AUTHOR [+6]

Abstract

Via hole connection passages made prior to lamination in outermost layers of multilayer printed circuit structures permit increased printed circuit packaging density and efficient fabrication.

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External Pre Lamination Via Connections in Multilayers

Via hole connection passages made prior to lamination in outermost layers of multilayer printed circuit structures permit increased printed circuit packaging density and efficient fabrication.

A problem associated with this type of fabrication is that the pre-preg material (usually "B" stage epoxy) tends to flow up through the holes in the outer layers, if not suitably contained during lamination and thereby cover extensive portions of the exterior copper surfaces. Removal of this excess pre-preg may be troublesome.

Elimination of excess flow can be accomplished by exercising suitable controls on: A) Hole diameter (preferably less than 0.060").

B) Pre-preg flow and "gel" characteristics.

C) Lamination temperature, pressure and "dwell" time.

D) Use of suitable TEFLON* release sheets to contain flow.

* Trademark of E. I. du Pont de Nemours & Co.

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