Patent ID: 7285734

Claim:
A semiconductor device comprising: a circuit board having an insulating substrate, a plurality of wiring layers arranged on the insulating substrate, and bumps formed on the wiring layers respectively, the bump being 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 contact a surface of the insulating substrate, with a cross sectional shape of the bump taken in a width direction of the wiring layer being such that a central portion is higher than both side portions and an upper surface of the bump has a rounded shape, and without a stepped portion formed in between the upper portion and the side portions of the bump; and a semiconductor chip mounted on the circuit board, wherein electrode pads of the semiconductor chip are connected to the wiring layers via the bumps, and each of the wiring layers has a narrow region, and each bump is formed in the narrow region.