Abstract: 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.
Type:
Grant
Filed:
July 19, 2001
Date of Patent:
September 16, 2003
Assignee:
International Business Machines Corporation
Inventors:
Kenneth J. Lubert, Curtis L. Miller, Thomas R. Miller, Robert D. Sebesta, James W. Wilson, Michael Wozniak
Abstract: An electronic package and method of making same in which a thermally conductive member is in thermally conductive communication with a semiconductor chip encapsulated within a dielectric material that surrounds portions of a thermally conductive member, semiconductor chip, and a predefined portion of a circuitized substrate. The present invention's thermally conductive member includes two portions of different bending stiffness to assure reduced interfacial stresses between the semiconductor chip and the circuitized substrate.
Type:
Grant
Filed:
October 29, 1999
Date of Patent:
January 14, 2003
Assignee:
International Business Machines Corporation