Patent ID: 7291915
Filing Date: 2007-11-06
Classification: H05K,Y10T

Abstract:
1. A circuit board, comprising: an insulating substrate having a surface; a first conductive layer having a first surface and a second surface opposite to the first surface, the first surface being provided on the surface of the insulating substrate, the second surface having a width smaller than a width of the first surface; a second conductive layer having a first surface and a second surface opposite to the first surface, the first surface of the second conductive layer provided on the second surface of the first conductive layer; an interface formed between the second surface of the first conductive layer and the first surface of the second conductive layer; a constricted portion is formed at the interface; and a third conductive layer covering the first conductive layer, the second conductive layer, and the constricted portion, wherein a width of the second surface of the second conductive layer is larger than the width of the second surface of the first conductive layer.