Core substrate and printed wiring board

摘要

The core layer of a core substrate is made of carbon fibers impregnated with resin. When the temperature of the core layer increases, the core layer suffers from an increase in the thickness because of thermal expansion of the resin. The core layer is sandwiched between the insulating layers containing glass fibers. The insulating layers serve to suppress an increase in the thickness of the core layer resulting from the thermal expansion of the core layer. Thermal stress is suppressed in the core substrate.