Patent ID: 6222609
Filing Date: 2001-04-24
Classification: G03F

Abstract:
A method for transferring a pattern image from a reticle to a photo-sensitive layer, comprising the steps of:a providing said reticle in a optical path from a light source to said photo-sensitive layer, said light source producing light have a light component which reacts with gas to form a reaction product that can accumulate on said reticle,b evacuating a gas that reacts with said light component to form a reaction product from a chamber containing said light source whereby accumulation of said reaction product in said chamber is prevented; andproviding an optical filter in said optical path and at a boundary of said chamber at which light from said light source exits said chamber, said reticle being placed in said optical path and outside said chamber, to thereby eliminate said light component that reacts with said gas before forming an image in said photo-sensitive layer.