Circuit board and method of fabricating circuit board

Abstract

A disclosed circuit board includes an insulating core layer that has a first surface and a second surface opposing each other, an insulating auxiliary member of which at least a part is disposed in the insulating core layer and which has a coefficient of thermal expansion (CTE) different from that of the insulating core layer, a first substrate portion that includes a first insulating layer which is disposed on the first surface, and a first circuit wiring which is embedded in the first insulating layer, and a second substrate portion that includes a second insulating layer which is disposed on the second surface, and a second circuit wiring which is embedded in the second insulating layer.

Dependencies are inferred from the claim text.