Patent ID: 7288729
Filing Date: 2007-10-30
Classification: H01L,H05K,Y02P

Abstract:
1. A circuit board comprising: an insulating substrate; a plurality of wiring layers arranged on the insulating substrate; and bumps formed on the wiring layers respectively, wherein the bump is provided across a longitudinal direction of a corresponding one of the wiring layers so as to extend over regions on both sides of the wiring layer and so as to be in contact with a surface of the insulating substrate, and a cross sectional shape of the bump taken in a width direction of the wiring layer is such that a central portion is higher than both side portions and an upper surface has a rounded shape, and without a stepped portion formed in between the upper portion and the side portions of the bump; and, wherein each of the wiring layers has a narrow region, and the bump is formed in the narrow region.