By performing plasma etching on the second surface of a semiconductor wafer on the first surface of which an insulating film is placed in dividing regions and on the second surface of which a mask for defining the dividing regions are placed, the second surface being located opposite from the first surface, the insulating film is exposed from an etching bottom portion by removing portions that correspond to the dividing regions. Subsequently, by continuously performing the plasma etching in the state in which the exposed insulating film is surface charged with electric charge due to ions in the plasma, corner portions put in contact with the insulating film are removed in the device-formation-regions. Consequently, individualized semiconductor chips having a high transverse rupture strength are manufactured.