Photomask and method of exposure using same

An exposure method whereby a light beam emitted from a light beam source is irradiated on a surface of a substrate through a hole provided on a photomask and having a prescribed pattern to form a part of prescribed patterns on said substrate, wherein said method is carried out by utilizing said photomask for the formation of at least part of a plurality of pattern parts of a pattern of a semiconductor device, said photomask comprising a plurality of main holes each of which passes a prescribed light beam that is irradiated onto the respective positions of a substrate, that make up at least a plurality of pattern parts, at locations that are opposite said respective pattern parts for said semiconductor device on said substrate, said photomask further comprising auxiliary holes having relatively smaller size with respect to those of said respective main holes, each of which passes a light beam of a degree that is not transferred onto a surface of said substrate at the time of exposure, said auxiliary holes being disposed between said main holes, wherein a light beam emitted from a deformed illumination source, which is bright around the periphery thereof, is irradiated onto said substrate through either of said main holes or said auxiliary holes of said photomask, said main holes and said auxiliary holes being arranged within said photomask in a periodic arrangement of holes, and further wherein said auxiliary holes are provided at either the intersection points of virtual matrix lines that run between prescribed positions in two directions or at intersection points of virtual lines that would be formed by dividing the virtual matrix lines into equal divisions.