Patent ID: 6028880
Filing Date: 2000-02-22
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:a noble gas,fluorine,a buffer gas;B) a blower for flowing the laser gas between the two spaced apart electrodes;C) a high-pressure fluorine source comprising a gas mixture at high pressure, said mixture comprising fluorine, said noble gas and said buffer gas;D) a gas inject manifold including an inject bottle having a volume of at least 0.3 liters and providing gas flow communication between said fluorine source and said inject bottle and between said inject bottle and said laser chamber;E) a fluorine monitoring means for monitoring changes in fluorine concentration in the chamber substantially continuously at least during laser operation; andF) a fluorine feedback control system including at least one low flow fluorine inject flow control valve, said system being programmed to automatically control fluorine flow from said fluorine source into said inject bottle and to control fluorine injection flow from said inject bottle into said laser chamber at a continuous or a substantially continuous rate based on feedback information from said fluorine monitoring means in order to permit said laser to operate within a desired sweet spot determined by fluorine concentration in the laser chamber.