Projection objective and method for its manufacture

摘要

A method of manufacturing a projection objective (22) of a microlithographic projection exposure apparatus (10). The projection objective (22) comprises at least one mirror (M1 to M6) that each have a mirror support (241 to 246) and a reflective coating (26) applied thereon. First imaging aberrations of a pre-assembled projection objective are measured. Before the coating (26) is applied, the mirror supports (241 to 246) are provided with a desired surface deformation (34). If the mirrors (M1 to M6) are not reflective for projection light without the coating (26), measuring light is used that has another wavelength. Alternatively, two identical mirror supports (246) may be provided. One support having a reflective coating is part of the pre-assembled projection objective whose imaging aberrations are measured. The other support is provided with surface deformations before coating and mounting the support into the objective.

主权项

1. A method, comprising:
assembling a plurality of optical elements and a first mirror to provide a first optical system, the first mirror comprising a first mirror support and a reflective coating thereon; measuring an optical property of the first optical system; providing a second mirror support that is at least substantially identical to first mirror support; producing a surface deformation in a second mirror support based on the measured optical property of the first optical system; after producing the surface deformation in the second mirror support, applying a reflective coating on the second mirror support to provide a second mirror; and replacing the first mirror contained in the first optical system with the second mirror to provide a second optical system, wherein the second optical system is a projection objective of a microlithographic projection exposure apparatus or an illumination system of a microlithographic projection exposure apparatus.