A photoresist is provided with an opening as a dummy pattern in a space area, i.e., a dummy region, other than a pattern of elements and circuits in one chip, thereby increasing the number of openings in the photoresist and performing ion implantation. This reduces the number of ions entering into the photoresist. As a result, the area in which the photoresist hardens due to the entering ions can be reduced, resulting in improved removability of the photoresist. The occurrence of charge-up can also be reduced. With a reduction in the area of regions other than the openings in the photoresist, a location where strong surface tension is generated can hardly be present. This allows the dimensional accuracy of the photoresist to be improved without making the photoresist thin in film thickness.