The present invention provides a semiconductor device comprising a semiconductor element and a copper member which are bonded to each other by a bismuth-based (Bi-based) bonding material having its melting temperature of not less than 250.degree. C., wherein silver (Ag) is diffused in a region of the bonding material in the vicinity of an interface thereof to the semiconductor element with an inclination of concentration of the silver from the interface, in order to realize a manufacture of the semiconductor device without using lead (Pb) at low cost.