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US 4,891,818 AGranted
Rare gas-halogen excimer laser
AssigneeAcculase, Inc.
InventorJeffrey I. Levatter
Life of this patent
Estimating the term…
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AssigneeAcculase, Inc.
InventorJeffrey I. Levatter
Estimating the term…
A rare gas-halogen excimer laser in which the laser gases are exposed only to compatible materials that react with the laser gases to produce stable reaction products having a low vapor pressure, so as to reduce contamination of the gases and optics. High-purity nickel is the preferred material for components that are electrically conductive, and high-purity alumina is the preferred material for components that are non-electrically conductive. No non-compatible materials are used. In another feature, magnetic fluid seals are provided for the laser's fan-shaft, to isolate the shaft bearings and thereby isolate any non-compatible lubricant for the bearings. The fan uses magnetic coupling so that an isolating enclosure may be placed over the magnetic fluid seal to prevent the leakage of gases into the surrounding environment if the seal ever fails. In yet another feature of the invention, the excimer laser includes a window assembly that is movable and sized such that a succession of non-overlapping portions of it may be selectively fixed in the path of the exiting laser beam. An excimer laser that is both reliable, safe and long-lasting is thereby provided.
In an excimer laser of the type in which a halogen gas is contained in a pressure vessel containing first and second electrodes for creating a laser discharge between the electrodes and generating a laser beam between first and second optical components at opposite end of the pressure vessel, a fan for circulating the gases, and a heat exchanger for cooling the gases, an improvement wherein the portions of the pressure vessel, first and second electrodes, fan and heat exchanger that are in contact with the halogen gas are fabricated entirely of a material that reacts with the halogen gas to form stable reaction products having a vapor pressure of less than about 10.sup.-6 torr, at normal operating temperatures, such that contamination of the gas by said pressure vessel, first and second electrodes, fan and heat exchanger is minimized and the lifetime of the excimer laser is increased.
An excimer laser comprising:
An excimer laser comprising:
A method for using an excimer laser of a kind that includes a pressure vessel containing a halogen gas, first and second electrodes located within the pressure vessel for exciting the gas located therebetween and generating a laser discharge, and first and second optical means located at opposite ends of the pressure vessel, aligned with the space between the first and second electrodes, for generating a laser beam therebetween, wherein the first optical means includes an optical component on which the laser beam impinges that is laterally movable relative to the beam, the method comprising steps of:
Dependencies are inferred from the claim text.