Method for producing an optical imaging system for a microlithography apparatus

A method of making an optical imaging system for an EUV microlithography apparatus, the optical imaging system comprising a plurality of optical modules, each module carrying a mirror disposed along an imaging beam path from an object plane of the optical imaging system to an image plane of the optical imaging system, the optical modules being located at assigned installation positions of a force frame, at least one of the optical modules being an exchangeable replacement module comprising a correction mirror, the method comprising:

• A) determining a surface shape of the correction mirror using a component measurement system;
• B) providing a tool module comprising a tool mirror, wherein:
• (i) the tool module comprises compatible mounting structures with respect to the installation position of the replacement module′ and
• (ii) the tool mirror comprises, according to a shape measurement made using a component measurement system, the same or substantially the same surface shape as the correction mirror;
• C) setting up an auxiliary imaging system by installing optical modules each comprising a mirror located at an assigned installation position of the force frame, the tool module being installed at the installation position of the replacement module;
• D) determining an imaging quality of the auxiliary imaging system after installation and rigid-body alignment of the optical modules in the installation positions using a system measurement system;
• E) comparing the measured imaging quality with a target imaging quality of the optical imaging system to determine an imaging quality error;
• F) determining a change in a surface shape of the correction mirror to reduce the imaging quality error;
• G) machining the correction mirror to change the surface shape to a modified surface shape suitable to reduce the imaging error;
• H) removing the tool module and installing the replacement module comprising the correction mirror comprising the modified surface shape;
• and
• I) after H), determining the imaging quality of the optical imaging system.