Side seal for wet lens elements

摘要

A method for protecting a wet lens element from liquid degradation is provided. The method includes applying a thin coating of an organoxy-metallic compound to the side portions of a wet lens element to leave behind an optically inert, light absorbing metal oxide film. A liquid shield coating is applied on top of the metal oxide coating. The two coating layers protect the wet lens element from liquid degradation when the side portion of the wet lens element is submerged into a liquid. In an embodiment, the wet lens element is an immersion lithography wet lens element and the liquid is an immersion lithography liquid.

主权项

1. A projection optics system within an immersion lithography system comprising:
a series of optical elements; a wet lens element having an object-side surface, an image-side optical surface, and a non-optical surface between the object-side surface and the image-side optical surface; a metal oxide layer on the non-optical surface; a polyurethane liquid shield coating that covers the metal oxide coating, wherein the polyurethane liquid shield coating is configured to be in contact with a liquid such that the metal oxide coating is protected from contact with the liquid, wherein the metal oxide coating is opaque to ultra-violet wavelengths.