OPTICAL SYSTEM FOR EXPOSURE EQUIPMENT USING A BIREFRINGENT METERIAL

摘要

PURPOSE: An optical system for an exposure equipment using a birefringent material is provided to embody a fine line width, by using a light source having a short wavelength and a broad bandwidth, and by inserting optical parts composed of the double refraction material to extend a depth of a focus. CONSTITUTION: An optical system for an exposure equipment comprises a first group of lenses(10), a second group of lenses(20), a polarized beam splitter(41), a first wave plate, a spherical mirror, a second wave plate and a third group of lenses(30). The first group of lenses are positioned in a rear part of a light source and a material surface. The second group of lenses change an optical axis by almost 90 degrees, positioned in a rear part of a reflector. The polarized beam splitter is composed of two prisms, positioned in a rear part of the second group of lenses. The first wave plate is positioned in an upper part of the polarized beam splitter. The spherical mirror is positioned in an upper part of the wave plate. The second wave plate is positioned in a lower part of the polarized beam splitter. The third group of lenses corresponds to an upper surface to which light is irradiated, positioned in a lower part of the parallel plate.