Microlithographic apparatus

摘要

A projection objective of a microlithographic projection apparatus has a wavefront correction device (42) comprising a mirror substrate (44; 44a, 44b) that has two opposite optical surfaces (46, 48), through which projection light passes, and a circumferential rim surface (50) extending between the two optical surfaces (46, 48). A first and a second optical system (OS1, OS2) are configured to direct first and second heating light (HL1, HL2) to different portions of the rim surface (50) such that at least a portion of the first and second heating light enters the mirror substrate (44; 44a, 44b). A temperature distribution caused by a partial absorption of the heating light (HL1, HL2) results in a refractive index distribution inside the mirror substrate (44; 44a, 44b) that corrects a wavefront error. At least the first optical system (OS1) comprises a focusing optical element (55) that focuses the first heating light in a focal area (56) such that the first heating light emerging from the focal area (56) impinges on the rim surface (50).

主权项

1. An apparatus, comprising:
an illumination system; a projection objective; and a wavefront correction device, comprising:
a mirror, comprising:
a mirror substrate having a front surface, a back surface and a circumferential rim surface extending between the front surface of the mirror substrate and the back surface of the mirror substrate; anda reflective coating supported by the front surface of the mirror substrate, the reflective coating configured to reflect projection light that impinges on the reflective coating;a first optical system configured to direct first heating light to a first portion of the rim surface so that at least a portion of the first heating light enters the mirror substrate, the first optical system comprising a focusing optical element configured to focus the first heating light in a focal area so that the first heating light that emerges from the focal area impinges on the first portion of the rim surface;a second optical system is configured to direct second heating light to a second portion of the rim surface so that at least a portion of the second heating light enters the mirror substrate; andan absorber configured so that, during use of the wavefront correction device, all first and second heating light beams impinge on the absorber after leaving the mirror substrate, wherein:
the second portion of the rim surface is different from the first portion of the rim surface;the wavefront correction device is configured so that, during use of the wavefront correction device, partial absorption of the first heating light and the second heating light causes a temperature distribution in the mirror substrate that deforms the mirror to at least partially correct a wavefront error; andthe apparatus is a microlithographic projection exposure apparatus.