CLAD MATERIAL STRUCTURE FOR ETCHED TRI-METAL CIRCUIT

PROBLEM TO BE SOLVED: To provide a clad material structure for an etched tri-metal circuit. SOLUTION: There are provided a process where a tri-metal material of a laminated set containing three layers of metal is formed; a process where a center layer of three metal layers is made from a first material while its upper and lower layers are made from second materials, and an outside surfaces of the upper and lower layers of the tri-metal material of each set are oxidized; a process where the tri-metal material of a plurality of sets forming the tri- metal clad material is separately claded; a process where the tri-metal clad material of each set is laid on the material of other set so as to generate tri- metal clad materials of a plurality of sets; and a process where a plurality of sets of tri-metal clad materials are rolled under a prescribed pressure and temperature to reduce the thickness of them.