Patent ID: 8415565

Claim:
A multilayer circuit substrate comprising: a laminated circuit portion in which conductive layers and resin insulating layers are alternately laminated, and which includes a first recess portion; a metallic heat spreader onto which an electronic component is mounted, and which is disposed in the first recess portion of the laminated circuit portion; and a metal substrate portion that is fixedly attached to a lowermost insulating layer, wherein: a height of the heat spreader is set to be equal to or less than a depth of the first recess portion of the laminated circuit portion, and the first recess portion of the laminated circuit portion is formed to have a depth from an uppermost conductive layer from among the conductive layers of the laminated circuit portion to a location directly above the lowermost insulating layer from among the insulating layers or directly above the lowermost conductive layer from among the conductive layers.