ALIGNMENT OF AN INTERFEROMETER MODULE FOR AN EXPOSURE TOOL

摘要

The invention relates to alignment of an interferometer module (60) for use in an exposure tool. An alignment method is provided for aligning an interferometer to the tool while outside of the tool. Furthermore, the invention provides a dual interferometer module, an alignment frame use in the alignment method, and an exposure tool provided with first mounting surfaces for cooperative engagement with second mounting surfaces (62, 63, 64) of an interferometer module.