Patent ID: 8179516

Claim:
An immersion photolithography system, comprising: a lens adapted for illumination by a predetermined wavelength of light during liquid immersion photolithography of a semiconductor wafer, the lens comprising: a transparent substrate having a first side and a second side, wherein the second side is substantially opposite the first side; a first layer of antireflection coating (ARC), the first layer of ARC formed on the first side of the transparent substrate and defining an outer surface of the lens, the first layer of ARC defining the outer surface of the lens being positioned closer to a light source for illuminating the lens than any other portion of the lens; a second layer of ARC, the second layer of ARC formed on the second side of the transparent substrate; and a layer of protective coating (PC) formed on the second layer of ARC, wherein the PC is positioned between a liquid used in the liquid immersion photolithography and the transparent substrate, the system configured such that the PC is in contact with an immersion liquid during the liquid immersion photolithography of a semiconductor device to protect the transparent substrate from the liquid, wherein the PC is an anti-corrosion layer.