Provided is a first copper alloy sputtering target comprising 0.5 to 4.0wt% of Al and 0.5wtppm or less of Si; a second copper alloy sputtering target comprising 0.5 to 4.0wt% of Sn and 0.5wtppm or less of Mn; the first or the second alloy sputtering target further comprising one or more selected from among Sb, Zr, Ti, Cr, Ag, Au, Cd, In and As in a total amount of 1.0wtppm or less; and a semiconductor element wiring formed by the use of the above target. 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.