Patent ID: 8158503

Claim:
A multilayer interconnection substrate, comprising: a multilayer interconnection layer including at least a first interconnection layer and a second interconnection layer stacked with an insulating layer provided therebetween; and a connection via in contact with a first land on the first interconnection layer and a second land on the second interconnection layer to electrically connect the first interconnection layer and the second interconnection layer, wherein the connection via includes an internal conductor and a metal film covering the internal conductor, the internal conductor being an aggregate of metal particles, the metal particles consisting of copper (Cu), the metal film is a diffused layer on surfaces of the metal particles, joining and coating each of the metal particles, the metal film joining and coating each of the metal particles has a first area and a second area interfacing with the first land and the second land, respectively, and the first area and the second area are substantially equal in area to the first land and the second land, respectively, and gold (Au) is diffused in the metal film.