Patent ID: 8373069

Claim:
An electronic component mounting substrate comprising: a support layer comprising a resin and having a first surface and a second surface on an opposite side of the first surface; an organic insulation layer formed on the first surface of the support layer and having a first surface and a second surface, the first surface of the organic insulation layer being on an opposite side of the first surface of the support layer, the second surface of the organic insulation layer being in contact with the first surface of the support layer; an inorganic insulation layer formed on the first surface of the organic insulation layer; a conductor formed on the second surface of the support layer and positioned to be mounted to a printed wiring board; and a first conductive circuit formed on the second surface of the organic insulation layer, wherein the inorganic insulation layer has a second conductive circuit and a pad for mounting an electronic component which are formed inside the inorganic insulation layer, the organic insulation layer has a via conductor formed inside the organic insulation layer and electrically connecting the second conductive circuit in the inorganic insulation layer and the first conductive circuit, and the support layer has a conductive post formed inside the support layer and electrically connecting the first conductive circuit and the conductor.