Self-cleaning method for semiconductor exposure apparatus

摘要

To an original plate holder 16 to which an original pattern plate 15 is set in ordinary exposure, a transmittable plate 20 having a concave-shaped concave portion 22 formed at a middle of a quartz glass plate is set in self-cleaning and irradiated with ultraviolet light emitted from a light source 11. The ultraviolet light is diffused through the concave lens of the transmittable plate 20 and an entire surface of a projection lens 17 is irradiated with it. Accordingly, molecular bonds of a contaminant adhering to the surface of the projection lens 17 are cut off with strong energy of the ultraviolet light, so that the contaminant is decomposed, vaporized, and then removed.