In a laser processing step S3, boundary sections among semiconductor elements 2 of a resist film 4 are exposed to a laser beam 13a, to thus form in the resist film 4 boundary grooves 5—which partition the semiconductor elements 2 from each other—and to uncover a surface 1b of a semiconductor wafer 1 in the boundary grooves 5. In a plasma etching step S6, the surface 1b of the semiconductor wafer 1 exposed in the boundary grooves 5 is etched by means of plasma Pf of a fluorine-based gas, to thus separate the semiconductor wafer 1 into individual semiconductor chips 1′ along the boundary grooves 5. Between the laser processing step S3 and the plasma etching step S6, there is performed processing pertaining to a boundary-groove-surface smoothing step S5 for smoothing, by means of plasma Po of oxygen gas, surfaces of the boundary grooves 5 having assumed an irregular shape in the laser processing step S3.