Power module substrate, method of producing the same, and semiconductor device including the substrate

Abstract

A power module substrate includes a ceramic substrate having a circuit pattern formed thereon, and a metal frame with which the ceramic substrate can be joined to a water-cooling type heat sink. The metal frame has a thickness equal to that of the ceramic substrate or the ceramic substrate having the circuit pattern, and is provided with plural perforations formed therein. Metal thin sheets having through-holes in communication with the corresponding perforations, and containing contacting portions having the undersides thereof contacted to at least a part of the circumferential surface of the ceramic substrate are disposed on the surface of the metal frame. In a semiconductor device, a semiconductor element is mounted onto the circuit pattern, and the power module substrate is joined directly to the water-cooling type heat sink by inserting male screws through the through-holes and the perforations, and screwing the male screws in the female screws of the water-cooling type heat sink.