Patent ID: 6240117
Filing Date: 2001-05-29
Classification: G03F,H01S

Abstract:
An excimer laser system comprising:A) a laser chamber containing:1) two spaced apart elongated electrodes;2) a laser gas comprising:at least one noble gas and fluorine,3) two window housings each housing a window,B) a blower for flowing the laser gas between the two spaced apart electrodes;C) a fluorine source;D) a metal fluoride trap;E) a fluorine monitor comprising an absorption cell and a light source for producing light in said absorption cell in a spectral range of relatively high absorption in F.sub.2 gas,F) a gas sampling circulation system for extracting a first small portion of said laser gas downstream of said blower directing said small portion to said metal fluoride and then directing all or a second portion of said first small portion through said sample cell and then to one of said window housings;G) a fluorine control system to regulate the concentration of fluorine gas in said laser chamber based on signals from said fluorine washer.