A method is used for manufacturing a semiconductor wafer. The back surface of a semiconductor wafer is ground. The back surface is cleaned with ozone water. The back surface of the semiconductor wafer is etched with a mixed acid that contains hydrofluoric acid and nitric acid. The cleaning and etching are carried out alternately such that the cleaning and etching are each repeated a plurality of times. The etching is performed after the grinding, beginning when the semiconductor wafer is wet with the ozone water. The cleaning is performed after the etching, beginning when the semiconductor wafer is wet with an etching solution.