A
package for a
semiconductor power device which comprises: a conductive bottom plate as a
heat sink; an insulating substrate mounted on the bottom plate; a
copper film formed on the insulating substrate to
expose a
peripheral region of the insulating substrate;
semiconductor chips disposed on the
copper film; a container arranged on the bottom plate, surrounding the insulating substrate; an external terminal supported through the container and connected electrically with the
semiconductor chips; and a
silicone gel filled within the container, wherein a solidified insulating material is disposed on an outer
edge region of the
copper film and the
peripheral region of the insulating substrate. Thus, reducing an
electric field across the interface and making it difficult to cause a creeping
discharge. A notch is formed in the bottom plate, and the notch is filled with a
high heat conductive resin. The notch is located outwardly apart from a region where the semiconductor chips are mounted. Thus, a creeping breakdown is prevented without sacrificing a heat
radiation effect of the bottom plate. Using a waterproof and flexible film to seal an inlet for filling the
silicone gel into the case, a
heat stress caused by an expansion and a shrinkage of the
silicone gel in response to a variation of temperatures is reduced, and it prevents the silicone gel from being wet. A
thermoplastic insulating resin is employed instead of the silicone gel.