US Patent 11096278 Ceramic circuit board

A ceramic circuit board includes a ceramic substrate and metal layers provided to both surfaces of the ceramic substrate and containing Al and/or Cu, wherein a measurement value α1 of a linear thermal expansion coefficient at 25° C. to 150° C. is 5×10−6 to 9×10−6/K, a ratio α1/α2 of the α1 to a theoretical value α2 of the linear thermal expansion coefficient at 25° C. to 150° C. is 0.7 to 0.95, and at least one of the metal layers forms a metal circuit.