Optical component that includes a material having a thermal longitudinal expansion with a zero crossing

摘要

There is provided an optical component. The optical component includes a material having a surface that heats to a maximum temperature (T_max) when subjected to radiation. The material has a temperature-dependent coefficient of thermal expansion (alpha(T)) of about zero at a temperature T₀ that is approximately equal to T_max. The optical component is suitable for use in any of an illumination system, a projection objective or a projection exposure system, as employed, for example, for EUV microlithography.