PURPOSE: To reduce a cost, improve solder wettability, decrease the reduction of the soldering property, and prevent the deterioration of adhesive strength by setting the content of a prescribed element higher at a portion to the prescribed depth from a surface of a copper material than that at the inside.
CONSTITUTION: At the time of the heat treatment of a copper material, aluminum, an aluminum compound, or a mixture of them are made to coexist, and an element having low standard formation free energy of an aluminum oxide is made to coexist with them. The content of the element at the portion to the depth of 0.1μm from the surface of the copper material is set higher than that at the inside. When the total content of the element is set to less than 5atm%, high conductivity is preserved, and high oxidation resistance can be easily obtained. Since oxidation reaction is suppressed, the deterioration of the soldering property caused by the oxidation of the Cu metal surface is improved, and the soldering property can be improved.
OKUYAMA KOJIRO
KAWASHIMA SHUNICHIRO
KUGIMIYA KOICHI
