Substrate for power module and method of producing substrate for power module

Abstract

A substrate for a power module of the present disclosure includes: an insulation sheet; a plurality of front surface patterns formed on a front surface of the insulation sheet and disposed adjacent to each other with a gap between the plurality of front surface patterns in a direction in which the insulation sheet expands; a power semiconductor element connected to the front surface pattern; a plurality of rear surface patterns formed on a rear surface of the insulation sheet and disposed adjacent to each other with a gap between the plurality of rear surface patterns in the direction in which the insulation sheet expands; and a connection pattern disposed in the gap to fill the rear surface in the gap between the neighboring rear surface patterns of the plurality of rear surface patterns and configured to electrically connect the neighboring rear surface patterns, wherein each of the rear surface patterns and at least one front surface pattern overlap with the insulation sheet disposed therebetween in a direction perpendicular to the insulation sheet, and the plurality of rear surface patterns are formed so that thermal stress acting on the plurality of rear surface patterns and thermal stress acting on the plurality of front surface patterns are balanced.