Heat resistant substrate incorporated circuit wiring board

A circuit wiring board comprising:

• a wiring board structure;
• and
• a heat resistant substrate accommodated in the wiring board structure and comprising a core substrate, a plurality of through hole conductors formed through the core substrate and a plurality of loading pads formed on a surface of the heat resistant substrate and electrically connected to the plurality of through hole conductors, respectively,
• wherein the plurality of loading pads of the heat resistant substrate is positioned to be connected to a plurality of electrodes of an electronic component, respectively, such that the electronic component is mounted on a surface of the wiring board structure, the core substrate of the heat resistant substrate has a first surface and a second surface on an opposite side of the first surface, the through hole conductors of the heat resistant substrate extend through the core substrate from the first surface to the second surface of the core substrate, the through hole conductors are formed at a pitch, the loading pads are positioned at a pitch which is smaller than the pitch of the through hole conductors in the core substrate, the heat resistant substrate further comprises a plurality of connecting pads electrically connected to the plurality of through hole conductors, respectively, and positioned to be connected to a conductor circuit of the wiring board structure, and the connecting pads are positioned at a pitch which is larger than the pitch of the through hole conductors of the core substrate.