International Business Machines Corporation

Stephen Alan Dunn, Deceased

Karl G Hoebener

Michael G McMaster

Charles H Crockett, Jr

Ku Ho Chong

A method of manufacturing a multiple layer circuit board with stacked vias of fine dimension and pitch. A base laminate with conductive pattern is coated with a dielectric which is photolithographically processed to create holes exposing selected regions of the underlying conductive pattern. The holes through the dielectric are plated to form via connections between the surface and the conductive pattern on the base laminate. The recess created by the via is filled with a conductive and plateable polymer which upon curing forms a conductive plug. A second dielectric layer is deposited on the board structure and in succession photolithographically processed to expose the underlying plated via and plug. The hole in the second dielectric is plated and filled with conductive polymer so as to create a second via vertically aligned with and electrically connected to the underlying first via. The ability to form fine pitch stacked vias is particularly important for printed circuit board structures such as carriers of flip chip die, in that the fine pitch of the solder ball array of the flip chip needs to be expanded and/or disbursed through multiple board layers with minimum area and electrical degradation.

Growing community of inventors

Georgetown, TX, United States of America

Stephen Alan Dunn, Deceased