CPC G03F 7/70775 (2013.01) [G03F 7/70916 (2013.01); G03F 7/70933 (2013.01)] | 16 Claims |
1. An apparatus comprising:
a position monitoring system configured to determine a position of a substrate with respect to a projection system configured to project a radiation beam through an opening in the projection system and onto the substrate, wherein a component of the position monitoring system is located beneath the projection system in use, and wherein the component comprises a reflective surface of an interferometer or a scale of a linear encoder; and
a baffle disposed between the opening and the component.
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