Patent ID: 7816611
Filing Date: 2010-10-19
Classification: H05K,Y10T

Abstract:
1. A circuit board comprising: a prepreg sheet impregnated with thermosetting resin, the prepreg sheet having a through-hole and a compressibility of less than 10%; a conductive paste containing thermosetting resin, the conductive paste filling the through-hole; a first circuit pattern formed on a surface of the prepreg sheet; and a second circuit pattern formed on another surface of the prepreg sheet, wherein a softening point of the thermosetting resin in the conductive paste is lower than a softening point of the thermosetting resin in the prepreg sheet, wherein the conductive paste comprises 85 percent by weight conductive filler, 12.5 percent by weight of the thermosetting resin in the through-hole, and 2.5 percent by weight acid anhydride-based hardener, and wherein the viscosity of the thermosetting resin in the conductive paste is lowest at a processing temperature in a heating and pressing process.