Window-like openings are cut through an aperture with cell projecting blocks using an electron beam system with pattern writing capability, and isolated patterns are supported by microbridges in respective openings. Widths of the microbridges are less than the resolution limitation of the electron beam, and thereby isolated patterns, such as frame-shaped shading patterns, can be written of a resist film, and the through-put of the lithography process can be increased. The aperture with cell projecting blocks can be formed so as to utilize both positive and negative resist film masks.