Abstract: Exposure of fine patterns on a photoresist is carried out by controlling the humidity and temperature of a gas to be supplied to an exposure apparatus separate from the ambient atmosphere.Temperature of the atmosphere at least in the vicinity of a photoresist is controlled in a predetermined range and air or gas to be supplied to the exposure space is humidified to a desired degree.Water content in the photoresist is kept uniform and constant by the specially controlled atmosphere and enables uniform pattern width of the exposed fine pattern all over the photoresist surface.

Abstract: A protective cover for photoprinting system comprises a cover portion made of a transparent thin plate of inorganic material, an antireflection multiple coating provided on at least one of the inner and outer surfaces of the cover plate, and a spacer arranged on the peripheral portion of the cover plate for keeping the inner surface of the cover plate away from the surface to be protected, e.g., pattern surface of photomask and sealing the space between them.Since the cover plate is made of inorganic material, the mechanical strength thereof is large. Since the cover plate is thin and the antireflection multiple coating is provided on the cover plate, absorption of light therein is little and confusion of the pattern image due to rays reflected by the boundaries of the cover plate is ignorable.