International Business Machines Corporation

Kenneth J Lubert

James Warren Wilson

Thomas R Miller

Robert David Sebesta

Michael Wozniak

Curtis L Miller

Ashwinkumar C Bhatt

David Erle Houser

Richard Jay Morenus

Mark Daniel Derwin

A high density printed wiring board is prepared by applying an essentially solid material into plated through holes such that the metallized layers within the through hole are unaffected by chemical metal etchants. In this manner, lateral surface metallized layers can exclusively be reduced in thickness by use of said chemical agents. These thinned lateral surface metallized layers are ultimately converted into fine pitch, 25 to 40 microns, circuitry, thereby providing high density boards. Since the through hole wall metallization is unaffected by the etching process, excellent electrical connection between the fine line circuitry is obtained. Various printed wiring board embodiments are also presented.

Fine pitch circuitization with filled plated through holes

A substrate comprising at least one optical fiducial hole and a plurality of holes surrounding at least substantially one-half of the at least one optical fiducial hole.

Avoiding polymer fill of alignment sites

The ends of thru-holes, disposed in components that are laminated together to form a composite structure are masked prior to lamination of the components to prevent bonding material bleed through the holes during the lamination process. The method effectively solves the problem of the need to remove laminate bleed from the outer surface of the composite structure after the joining process.

Method for forming a multi-layered circuitized substrate member

Apparatus operative in conjunction with a wire routing and bonding machine, or the like, to selectively penetrate a maze of parallel wires on a printed circuit board and expose an area on the board so that additional wires may be suitably bonded to the exposed area. Utilizing the pressure it experiences when contacting the board surface, the apparatus operates to avoid damage to the printed circuit board surface and at the same time has a high reliability for clearing of wires from the selected area.

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Endicott, NY, United States of America

Kenneth J Lubert