Patent ID: 7709813
Filing Date: 2010-05-04
Classification: G02B,G03F,Y10T

Abstract:
1. An immersion microlithography system utilizing an exposure light for exposing a pattern onto a substrate, the system comprising: a substrate stage configured to hold the substrate as the pattern is being exposed by the exposure light onto the substrate; a projection-optical system situated relative to the substrate stage and a source of exposure light so as to direct the exposure light onto the substrate, the exposure light from the projection-optical system passing through an exposure-light-transmissive immersion liquid situated between the projection-optical system and the substrate; and an optical sensor associated with the substrate stage, the optical sensor comprising (a) a light sensor; and (b) an optical window through which a beam of sensor light is transmitted to the light sensor, the optical window comprising a window substrate that is transmissive to at least one wavelength of the sensor light, the window substrate having an incidence surface that is decorated with sub-wavelength asperities arranged so as to render the incidence surface solvophobic to the immersion liquid.