Patent ID: 8461464
Filing Date: 2013-06-11
Classification: C23C,H01L,Y10T

Abstract:
1. A circuit board comprising: a substrate with oppositely facing first and second sides; an insulating layer on the second side of the substrate, the insulating layer having oppositely facing first and second sides, the first side thereof and the substrate second side being adjacent; first holes extending through the substrate; insulating material partially filling at least some of the first holes and extending from the second side, the insulating layer partially filling the at least some holes in varying amounts; first conductive material lining the first holes from the first side; second holes extending through the insulating layer and in alignment with the first holes, the second holes extending to the first conductive material lining the first holes so that the first and second holes are interconnected, the second holes being smaller in diameter than the first holes; and second conductive material lining the second holes from the insulating layer first side, the first conductive material in each first hole being in electrical communication with the second conductive material in alignment with that first hole.