Coudert Brothers
Method of fabrication of multiple-layer high density substrate
 A method of fabricating a multi-layer interconnected substrate structure. The inventive method includes forming a multi-layer structure from multiple, pre-fabricated power and/or signal substrates which are laminated together. A drill is then used to form a via through the surface of a ring-type pad down to a desired depth in the multi-layer structure. The via hole is cleaned and then filled with a conductive material. The via so formed between two or more substrates is self-aligned by using the ring pad(s). This contributes to an increased signal routing density compared to conventional methods. 
Fujitsu Limited
H
H05K
inventional
Michael Guang-Tzong Michael G. Solomon I. William T. Wen-Chou Vincent
Lee Peters Beilin Chou Wang