Patent ID: 8735741
Filing Date: 2014-05-27
Classification: H01L,H05K

Abstract:
1. A circuit board, comprising: a substrate; a through hole penetrating the substrate along with a direction of a thickness thereof; and a through hole conductor covering an inner wall of the through hole, wherein the substrate comprises a first fiber layer, a second fiber layer, and a resin layer arranged between the first fiber layer and the second fiber layer, each of the first fiber layer and the second fiber layer has a plurality of fibers and a resin arranged among the plurality of the fibers, the resin layer contains a resin and doesn't contain a fiber, the inner wall of the through hole, in a cross-section view along with the direction of the thickness of the substrate, comprises a curved depression in the resin layer, the curved depression comprises one end at a boundary between the resin layer and the first fiber layer, and other end at a boundary between the resin layer and the second fiber layer, and a portion of the through hole conductor is arranged in the curved depression.