Optical element for projection lens of projection exposure system, has base portion that is provided with volume region such that thermal conductivity of thermal insulation layer located opposite to volume region is reduced

摘要

The optical element (33) has a base portion (34) that is provided with a volume region for the transmission of UV radiation. The thermal conductivity of a thermal insulation layer (61) which is located opposite to the volume region of the base portion is reduced. The thickness of the thermal insulation layer is set to predetermined range. Several cavities are provided in the thermal insulation layer. The base portion is made of quartz glass. A thermal insulation layer is made of aerogel. Independent claims are included for the following: (1) a projection lens; and (2) a projection exposure system for immersion lithography.