A semiconductor surface cleaning agent containing a compound the molecule of which has a nitrogen atom having an unshared electron pair and used for cleaning the surface of a semiconductor on which copper wiring is provided, and a method for cleaning the surface of a semiconductor characterized by treating the surface of a semiconductor on which copper wiring is provided with such a cleaning agent. The cleaning agent does not corrode the copper wiring (copper thin film) on the semiconductor and SiO.sub.2 of the interlayer insulating film, does not impair the flatness of the surface, and is effective in removing CuO and particles adhering to the surface of the Cu-CMP step.