To improve homogeneity of in-plane distribution of ion amount implanted to a wafer surface.
While amplitude-modulating a draw-out voltage in a draw-out voltage modulation part 12a, ions are drawn out from an ion source 1, and ion beams drawn out from the ion source 1 are driven into a wafer W. By this, while broadening a beam diameter, injection energy becomes enabled to have some latitude. Due to this, the impurity concentration distribution can be made less steep in the depth direction, and the homogeneity of the in-plane distribution can be improved. In another embodiment, while modulating an electromagnetic field added to a mass spectrometer 3, the ion implantation is carried out. Furthermore, in another embodiment, while amplitude-modulating acceleration voltage added to an accelerating tube 6, the ion implantation is carried out.
Yoshiaki Naito
Cui Shu Tetsu