Provided is a copper alloy sputtering target containing 0.01 to (less than) 0.5 wt % of at least 1 element selected from Al or Sn, and containing Mn or Si in a total amount of 0.25 wtppm or less. 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. A semiconductor element wiring formed with this target is also provided.