Development of high-performance parallel exposure I-line UV light source

Abstract

UV light source and high-pressure mercury lamps are usually used as a projecting light source of foreign exposure light source recently, including a spherical mirror ellipse, an optical integrator, and a parallel lens. The light source system is the most crucial technology to achieve better image quality and better uniformity of light field. High-stability, high-uniformity, and high-parallelism light source should be created to ensure the stability of all processes. In this research, two sets of Fly's eye lens are used as an optical integrator for combining with the redesigned parallel lens, which are evaporated AR coating to increase the transmittance of overall optical system up to 80% and the uniformity of light field. Equivalent doublets are also proposed to improve the original design of single parallel lenses for reducing the thickness, curvature, and divergent angle of a single lens so as to enhance the efficiency of light irradiation.