Patent attributes
An immersion optical projection system for photolithography is provided. A transparent plate is located between a last lens element and the wafer during a usage of the system. The transparent plate has a lens-side surface and a wafer-side surface. The system is adapted to have a layer of lens-side fluid located between the last lens element and the lens-side surface of the transparent plate, e.g., when the last lens element is operably located over the wafer during a photolithography process. The system is also adapted to have a layer of wafer-side fluid located between the wafer-side surface of the transparent plate and the wafer, during a usage of the system. The wafer-side fluid may or may not be fluidly connected to the lens-side fluid. The wafer-side fluid may or may not differ from the lens-side fluid.
