To provide a ceramic substrate for a semiconductor module excellent in a heat dissipation effect which alleviates a thermal stress to the ceramic substrate by joining at a low temperature comparatively when a metal plate is joined to the ceramic substrate and which enables to join the thick metal plate, and to provide a method of manufacturing it.

Layers 6 and 6 containing a metal nano particle are made to be interposed between the ceramic substrate 1 and the metal plates 7 and 8, heat-treated and joined. A heat treating temperature is 200-300°C, and the thickness of at least one of the above metal plates is desirable to be 1 mm or more. And, the above metal nano particle is mixed with a volatile organic solvent, and as paste, it is desirable to apply to the above ceramic substrate or the above metal plate.