In Proc. SPIE Vol. 4440, p. 202-208, Lithographic and Micromachining Techniques for Optical Component Fabrication, Ernst-Bernhard Kley; Hans-Peter Herzig; Eds., Vol. 4440 (November 2001), pp. 202-208.
An index matching fluid has been used to minimize the effect of interference fringes which develop when contact printing diffraction gratings on silicon wafers. These fringes are the result of interference effects when there is a small but uneven gap between the photomask and resist surface. They are especially troublesome when printing and etching large area, coarse diffraction gratings on the surface of silicon wafers and silicon disks.