Patent ID: 6863962

Claim:
A thermally conductive substrate comprising a thermosetting resin sheet, a first wiring pattern formed on one side of said sheet, a second wiring pattern formed on an other side of said sheet, at least one of the first wiring pattern and the second wiring pattern being formed from a metallic foil, and a via hole formed in a thickness direction of said sheet for electric connecting of said first wiring pattern and said second wiring pattern, wherein said thermosetting resin sheet comprises 70 to 95 weight parts of an inorganic filler, and 5 to 30 weight parts of thermosetting resin composition, the coefficient of thermal expansion is in the range of 8 to 20 ppm/° C., and the thermal conductivity is in the range of 1 to 10 W/mK, and at least one additive selected from the group consisting of a coupling agent, a dispersing agent, a coloring agent and a tack free agent.