Patent ID: 7514779
Filing Date: 2009-04-07
Classification: H01L,H05K

Abstract:
1. A multilayer wiring board comprising: a first resin insulating layer; a conductor circuit formed as a composite metallic layer, said conductor circuit having a base disposed on the first resin insulating layer, the composite layer including a first metal film and a second metal film which has a thickness thinner than a thickness of the first metal film, the first metal film having a top surface, the second metal film having a bottom surface and a top surface, an entirety of the top surface of the first metal film being electrically and directly connected to the bottom surface of the second metal film with a metal-to-metal contact region between the first and second metal films being at least as wide as the top surface of the first metal film, the top surface of the first metal film being smaller than the bottom surface of the second metal film, and the top surface of the second metal film having a rounded edge and a roughened layer, said bottom surface of the second metal film extending linearly at a same level from the metal-to-metal contact region beyond said top surface of the first metal film; and a second resin insulating layer separate from the first resin insulating layer and provided on the conductor circuit to cover the conductor circuit including the first and second metal films, wherein the top surface of the first metal film being smaller than the bottom surface of the second metal film reduces stress in the second resin insulating layer.