Patent ID: 8169784

Claim:
A circuit module comprising: a first module substrate comprising a first substrate comprising a metal, at least a top surface of the first substrate being electrically insulated, a plurality of first conductive patterns made of an electrically-conductive material and disposed on the top surface of the first substrate, and a power semiconductor device electrically connected with the first conductive patterns and mounted on the first substrate; a second module substrate comprising a resin substrate, a plurality of second conductive patterns made of an electrically-conductive material and disposed on a top surface of the resin substrate, and a drive device electrically connected with the second conductive patterns and controlling the power semiconductor device; and a casing member comprising a resin and holding opposing sides of the first module substrate and opposing sides of the second module substrate that is disposed above the first module substrate with an empty space in between, wherein the drive device is positioned off the center of the resin substrate, and the second module substrate is configured to be an outermost top cover of the circuit module, and, in plan view of the circuit module, there is an opening between an edge of the second module substrate and a sidewall of the casing member so that the empty space is connected to atmosphere outside the circuit module through the opening.