Aimed at preventing a laser light beam profile from fluctuating, and by using the fact that there is a substantially proportional relation between the beam profile and the charging voltage as well as between the beam profile and the composition or the total pressure of the laser gases, an excimer laser device comprises a laser chamber containing laser gases which are excited by initiating an electric discharge in the laser chamber to output laser light, a beam profile detector for detecting a beam profile of the output laser light, and a controller for controlling a electric discharge voltage (excitation intensity) and composition or total pressure of the prescribed types of laser gases in such a way that the beam profile is shaped as desired based on detection results of the beam profile detector. An excimer laser feedback control circuit detects the output laser beam width and controls the beam width by controlling one or more of the laser voltage, composition of the laser gas, pressure or partial pressure of the laser gas, or feed rate of a laser gas. The laser gas may comprise a halogen, buffer, or rare gas.
A gas laser oscillator (2) that excites a laser gas to generate laser light includes a circulation path (9) for the laser gas, a circulation means (14) for circulating the laser gas through the circulation path, a pressure detection means (16) for detecting the pressure of the laser gas in the circulation path, an electric power detection means (11) for detecting electric power to drive the circulation means, a storage means (35) for storing the relationship between the pressure of the laser gas and the electric power of the circulation means during the period of normal operation of the circulation means for each kind of the laser gas, and a laser gas determination means (31). The laser gas determination means determines the kind of the laser gas based on the pressure of the laser gas and the electric power of the circulation means detected during the period of normal operation of the circulation means, and the relationship between the pressure of the laser gas and the electric power of the circulation means stored in the storage means. Due to this, the laser gas is determined without generating a discharge voltage. If the laser gas cannot be determined, it may be possible to judge that the laser oscillator is anomalous.
A gas laser outputs a prescribed high power from the start of laser oscillation immediately after the laser gas is changed. The laser, in which used laser gas in a laser chamber (1) is replaced with a fresh laser gas, is provided with: a gas leaving means, which leaves a prescribed amount of used gas for mixing with the fresh laser gas during laser gas replacement, or an impurity gas adding means which provides a prescribed amount of impurity gas for mixing with the fresh laser gas; and a controller (11). It is preferable that the concentration of the used gas after a replacement is within a range of 1.5-60%. The gas leaving means can be a gas discharge control mechanism (10), which controls the amount of used gas exhausted so that a prescribed amount of used gas can be left for mixing with the fresh gas, or a laser gas container (21), which can provide a prescribed amount of stored used gas for mixing with the fresh gas. The impurity gas adding means can be a laser gas cylinder containing a prescribed concentration of impurity gas or an impurity gas container (44).
The present invention provides a wavelength-stabilized narrow band excimer laser device which has a discharge tube, a cavity formed of both an output mirror at a front side and a total reflection mirror at a rear side, and a wavelength selective element positioned between the front and rear mirrors, wherein the output mirror, the total reflection mirror and the wavelength selective element are securely fixed on a supporting structure which is mounted via a vibration removing device over a mount on which the discharge tube is mounted so that the output mirror, the total reflection mirror and the wavelength selective element are free from any vibration of the discharge tube. The wavelength selective element comprises at least a prism and at least an etalon wherein the above novel wavelength-stabilized narrow band excimer laser device may further have at least a beam splitter for causing a laser beam sprite, a spectroscope for measuring a center wavelength of the split laser beam, a beam-position detector for measuring a direction of the laser emission, a first driver for adjusting a laser beam transmission angle of the etalon, a second driver for adjusting an angle of the total reflection mirror, and a controller for controlling both the first driver in accordance with variations in the center wavelength of the laser beam measured by the spectroscope and the second driver in accordance with variations in the direction of the laser emission measured by the beam-position detector.
Xenon gas is added from a small-sized Xe gas cylinder (15) to the excimer laser gas inside a chamber (10) supplied from an Ar/Ne gas cylinder (13) and an Ar/Ne/F.sub.2 gas cylinder (14), the xenon gas proportion is detected by an Xe gas sensor (16), and the supply of the xenon gas supplied to the chamber (10) from the Xe gas cylinder (15) is controlled by a gas controller (18).
An excimer laser system with a fluorine control having a fixed volume inject bottle in which fluorine is injected prior to it being injected into the laser chamber. A manifold and feedback control system is provided to permit precise injection at rates approaching continuous fluorine injection. The system permits the laser to be operated in a small sweet spot as measured by a narrow range of charging voltage.
