Patent ID: 7408120
Filing Date: 2008-08-05
Classification: H05K

Abstract:
1. A printed circuit board having axially parallel via holes, comprising: a plurality of circuit layers, on which circuit patterns are formed; a plurality of insulating layers interposed between the plurality of circuit layers, thereby forming internal and external circuit layers; a plurality of via holes having a continuous curvilinear section, which extends perpendicular to a surface of any one of the plurality of circuit layers and which is plated with a first conductive material on walls thereof; an outer ground via hole having a continuous curvilinear section surrounding at least two via holes of the plurality of via holes, which extends transverse to and for a distance equal to the thickness of at least three insulating layers having internal circuit layers disposed therebetween, the outer ground via hole extending in an axial direction of the via hole surrounded thereby while being separated from a wall of the via hole by a predetermined distance and which is plated with a second conductive material on the wall thereof; an insulating material packed between the via hole, which is surrounded by the outer ground via hole, and the outer ground via hole; and wherein the via hole, which is surrounded by the outer ground via hole, is selected from the group consisting of: