A first copper alloy sputtering target comprising 0.5 to 4.0 wt % of Al and 0.5 wtppm or less of Si and a second copper alloy sputtering target comprising 0.5 to 4.0 wt % of Sn and 0.5 wtppm or less of Mn are disclosed. The first and/or the second alloy sputtering target can further comprise one or more elements selected from among Sb, Zr, Ti, Cr, Ag, Au, Cd, In and As in a total amount of 1.0 wtppm or less. A semiconductor element wiring formed by the use of the above targets is also disclosed. The above copper alloy sputtering target allows the formation of a wiring material for a semiconductor element, in particular, a seed layer being stable, uniform and free from the occurrence of coagulation during electrolytic copper plating and exhibits excellent sputtering film formation characteristics.