With regard to the resist-stacking process, it was proposed that the implantation of ions whose acceleration voltage was below could make the lower-layer resist insoluble for the upper-layer resist-patterning process. However, the lower-layer resist pattern is observed to be removed after the upper-layer resist patterning in a pattern. In another type of a pattern, there are caves in the bottom of the lower-layer resist pattern after the upper-layer resist patterning. From the calculation of the projected range of the ions, it is found that the ions cannot reach the bottom of the lower-layer resist pattern, and therefore the bottom of the lower-layer resist is not hardened. The removal is due to the dissolution of the bottom in the lower-layer resist during the development of the upper-layer resist pattern. When the acceleration voltage of the implanted ions is set so that the projected range of the ions is larger than the resist thickness, the lower-layer resist can be made effectively insoluble for the upper-layer resist-patterning process. The ion-implanted pattern can be used as the etching mask. Moreover, the ions can be prevented from penetrating the film to be etched by adjusting the thicknesses of stacked antireflective coating.