Abstract: A method of operating a laser system for increasing the lifetimes of optical components of the resonator includes the steps of configuring the laser system to initially output laser pulses at an energy in a range above a predetermined energy for industrial lithographic processing, and attenuating the energy of the output pulses to the predetermined energy. A further step includes reducing an amount of attenuation as optics of the laser resonator age to maintain the laser pulses at the predetermined energy, or reducing the amount of attenuation to produce pulses having a higher energy than the predetermined energy.

Abstract: An excimer or molecular fluorine laser system is provided which emits a laser beam during operation and has a gas mixture with a gas composition initially provided within a discharge chamber. The laser system includes a discharge chamber containing a laser gas mixture at least including a halogen-containing species and a buffer gas, multiple electrodes within the discharge chamber and connected to a discharge circuit for energizing the gas mixture, a resonator for generating a laser beam, an electrostatic precipitator for having a voltage applied thereto and for receiving and precipitating contaminant particulates from a flow of the gas mixture, and a processor for monitoring the corona discharge ignition voltage of the electrostatic precipitator and for determining a status of said gas mixture based on the monitored voltage.

Abstract: An F2-excimer laser has multiple closely-spaced spectral lines of interest around 157 nm, and one of the lines is selected by wavelength selection optics. The wavelength selection optics of a first preferred embodiment include a birefringent Brewster window enclosing the laser gas volume of the discharge chamber. The window preferably comprises MgF2 and is located at one end of the discharge chamber. One line is selected of the two when the optical thickness of the window is selected in coordination with rotatably adjustable, orthogonal refractive indices of the window. The transmissivity of the window is dependent on the orthogonal refractive indices and the optical thickness of the window. The wavelength selection optics of a second preferred embodiment include are at least partially within the laser active volume. In this way, line selection is performed in a manner which optimizes the combination of optical and discharge efficiency, resonator size and cost.

Abstract: An F2-excimer laser has multiple closely-spaced spectral lines of interest around 157 nm, and one of the lines is selected by wavelength selection optics. The wavelength selection optics of a first preferred embodiment include a birefringent Brewster window enclosing the laser gas volume of the discharge chamber. The window preferably comprises MgF2 and is located at one end of the discharge chamber. One line is selected of the two when the optical thickness of the window is selected in coordination with rotatably adjustable, orthogonal refractive indices of the window. The transmissivity of the window is dependent on the orthogonal refractive indices and the optical thickness of the window. The wavelength selection optics of a second preferred embodiment include are at least partially within the laser active volume. In this way, line selection is performed in a manner which optimizes the combination of optical and discharge efficiency, resonator size and cost.

Abstract: The invention provides an once through fan for an excimer laser apparatus having a reduced vibration and being capable of increasing a rotational speed. In order to obtain this, in an once through fan (1) for an excimer laser apparatus provided with a blade portion (6) having a plurality of blades, a rotary shaft (4) for rotating the blade portion and a magnetic bearing (7) rotatably supporting the rotary shaft in a non-contact manner so as to circulate a laser gas sealed within a chamber (2) in accordance with a rotation of the blade portion, a rotor (21) of a motor (23) installed within the chamber (2) and rotating the rotary shaft (4) is mounted on an outer peripheral portion of the rotary shaft, and at least one magnetic bearing (7, 7) for supporting the rotary shaft is arranged in each of both sides in an axial direction of the rotor.

Abstract: An excimer or molecular fluorine laser system includes a laser tube filled with a gas mixture including fluorine and a buffer gas, and multiple electrodes within the laser tube connected with a pulsed discharge circuit for energizing the gas mixture. At least one of the electrodes is longer than 28 inches in length, preferably two main electrodes are each extended to greater than 28 inches in length. The laser system further includes a resonator including the laser tube for generating a pulsed laser beam having a desired energy. The laser system is configured such that an output beam would be emitted having an energy below the desired energy if each of the electrodes were 28 inches in length or less, and the laser system outputs a beam at the desired energy due to the length of the electrodes being extended to a length greater than 28 inches.

Abstract: Disclosed is an exposure apparatus to be used with an excimer laser as a light source, which includes an optical system disposed along a path of excimer laser light, a chamber for accommodating the optical system therein and having an inside space being able to be replaced by a predetermined gas, a gas circulation mechanism having a gas discharging port for discharging a gas from the chamber and a gas supply port for supplying a gas into the chamber, and a switching device for selectively using plural purifiers disposed in a portion of a gas circulation path.

Abstract: This invention relates to an excimer laser oscillation apparatus which has a laser chamber which stores a laser gas containing a gas mixture of at least one inert gas selected from the group consisting of Kr, Ar, and Ne, and F2 gas, and in which an inner surface thereof has a reflection-free surface with respect to light of a desired wavelength of 248 nm, 193 nm, or 157 nm, and the uppermost surface of the inner surface consists of a fluoride, an optical resonator which is made up of a pair of reflection mirrors arranged to sandwich the laser chamber therebetween, and in which the reflectance of the reflection mirror on the output side is 90% or more and microwave introduction means, arranged on the laser chamber, for continuously exciting the laser gas in the laser chamber.

Abstract: A laser for an excimer or molecular fluorine laser includes an electrode chamber connected with a gas flow vessel and having a pair of main electrodes and a preionization unit each connected to a discharge circuit. A spoiler is provided within the electrode chamber and is shaped to provide a more uniform gas flow through the discharge area between the main electrodes, to shield one of the preionization units from one of the main electrodes, and to reflect acoustic waves generated in the discharge area into the gas flow vessel for absorption therein. A spoiler unit may include a pair of opposed spoiler elements on either side of the discharge area. One or both main electrodes includes a base portion and a center portion which may be a nipple protruding from the base portion. The center portion substantially carries the periodic discharge current such that the discharge width is and may be significantly less than the width of the base portion.

Abstract: A reliable, modular, production quality F2 excimer laser capable of producing, at repetition rates in the range of 1,000 to 2,000 Hz or greater, laser pulses with pulse energies greater than 10 mJ with a full width half, maximum bandwidth of about 1 pm or less at wavelength in the range of 157 nm. Laser gas concentrations are disclosed for reducing unwasted infrared emissions from the laser. Also disclosed are UV energy detectors which are substantially insensitive to infrared light. Preferred embodiments of the present invention can be operated in the range of 1000 to 4000 Hz with pulse energies in the range of 10 to 5 mJ with power outputs in the range of 10 to 40 watts. Using this laser as an illumination source, stepper or scanner equipment can produce integrated circuit resolution of 0.1 &mgr;m or less. Replaceable modules include a laser chamber and a modular pulse power system.

Abstract: A method is provided for determining the status of a gas mixture of a laser system including a gas discharge laser which generates an output beam and has a discharge chamber containing a gas mixture within which energy is supplied to the gas mixture by a power supply via application of a driving voltage to a discharge circuit. A master data set of an output parameter such as any of output beam energy, bandwidth, spectrum width, long axial beam profile, short axial beam profile, beam divergence, energy stability, energy efficiency, width of the discharge, temporal beam coherence, spatial beam coherence, spatial pulse width, amplified spontaneous emission and temporal pulse width versus an input parameter such as driving voltage is generated corresponding to an optimal gas mixture status, preferably after a new fill and typically at the factory, and alternatively following a new fill at the fab.

Abstract: The present invention provides a reliable modular production quality excimer laser capable of producing 10 mJ laser pulses in the range of 1000 Hz to 2000 Hz with a full width half, maximum bandwidth of about 0.6 pm or less. Replaceable modules include a laser chamber, a pulse power system comprised of three modules; an optical resonator comprised of a line narrowing module and an output coupler module; a wavemeter module, an electrical control module, a cooling water module and a gas control module. Important improvements have been provided in the pulse power unit to produce faster rise time and improved pulse energy control.

Abstract: A system is provided for delivering a laser beam of wavelength less than 200 nm from a laser, such as an F2 laser or ArF laser, through a sealed enclosure sealably connected to the laser, and preferably to another housing, leading ultimately to a workpiece. The enclosure is preferably evacuated and back-filled with an inert gas to adequately deplete any air, water, hydrocarbons or oxygen within the enclosure. Thereafter or alternatively, an inert gas flow is established and maintained within the enclosure during operation of the laser. The inert gas preferably has high purity, e.g., more than 99.5% and preferably more than 99.999%, wherein the inert is preferably nitrogen or a noble gas. The enclosure is preferably sealed by a window transparent to the sub-200 nm radiation for preventing contaminants generated in the enclosure from entering the housing and contaminating surfaces therein. The enclosure is preferably made of steel and/or copper, and the window is preferably made of CaF2.

Abstract: An improved excimer laser system for use in medical procedures such as transmyocardial laser revascularization is disclosed. The laser uses a number of novel design features to reduce the footprint and weight of the laser over prior designs; e.g., an improved recirculating fan design that employs a non-contacting magnetic coupling between fan motor and fan, and an improved laser diffusion mixer at the output.

Abstract: An excimer laser system with an automatic fluorine control system to permit precise control of the fluorine concentration within an F2 “sweet spot” in a gas discharge laser chamber. This is done with a computer control system which monitors laser parameters, determines &Dgr;E/&Dgr;V, the change of pulse energy with voltage, and automatically and precisely controls the fluorine concentration based on &Dgr;E/&Dgr;V without the need to actually measure the fluorine concentration. The present invention is especially useful in lithography environments in which photo resist having a wide range of sensitivity are used. The present invention permits operation of the laser at substantially maximum efficiency over a wide range of pulse energy outputs.

Abstract: Methods and structural changes in gas discharge lasers for minimizing wavelength chirp at high pulse rates. Applicants have identified the major cause of wavelength chirp in high pulse rate gas discharge lithography lasers as pressure waves from a discharge reflecting back to the discharge region coincident with a subsequent discharge. The timing of the arrival of the pressure wave is determined by the temperature of the laser gas through which the wave is traveling. During burst mode operation, the laser gas temperature in prior art lasers changes by several degrees over periods of a few milliseconds. These changing temperatures change the location of the coincident pressure waves from pulse to pulse within the discharge region causing a variation in the pressure of the laser gas which in turn affects the index of refraction of the discharge region causing the laser beam exiting the rear of the laser to slightly change direction.

Abstract: A wavelength system for measuring the bandwidth of a narrowband laser utilizing prior art equipment normally provided for calibrating wavelength measurement equipment. The prior art includes a wavemeter for measuring incremental changes in wavelength and an atomic wavelength reference for calibrating the wavemeter. The atomic wavelength reference includes a vapor cell for providing a vapor having at least one absorption line near a desired operating wavelength. The system includes a wavelength tuning device with a tuning range sufficient to tune the laser to operate at the wavelength of the absorption line in order to calibrate the wavemeter. Measurements of the bandwidth of the absorption spectrum obtained by scanning the laser output wavelength over the absorption line are used to estimate the bandwidth of the output beam. This estimate in a preferred embodiment is used to confirm the accuracy of the normal bandwith measurements. In a preferred system the laser is a KrF laser and the vapor is iron vapor.

Abstract: An excimer laser with optical pulse multiplication produced by separating a laser beam into a plurality of beams and multiplying the pulse rate in each beam. A pulse multiplier optical system receives the laser output beam and produces multiple output beams, each beam having a larger number of pulses with substantially reduced intensity values as compared to the laser output beam. In a preferred embodiment, CaF2 flats are used along with maximum reflection mirrors to split the laser beam into four beams each with a 4× increased pulse rate. The present invention is particularly important as an improvement to the ArF excimer laser industry to reduce two-photon absorption damage to optical equipment in lithography machines.

Abstract: A gas laser device. The device includes a laser chamber having at least one active gas and a device for purifying gas. The purified gas is in communication with the free exchange of gas with the chamber. This device may be used with high powered gas lasers.

Abstract: A laser for an excimer or molecular fluorine laser includes an electrode chamber connected with a gas flow vessel and having a pair of main electrodes and a preionization unit each connected to a discharge circuit. A spoiler is provided within the electrode chamber and is shaped to provide a more uniform gas flow through the discharge area between the main electrodes, to shield one of the preionization units from one of the main electrodes, and to reflect acoustic waves generated in the discharge area into the gas flow vessel for absorption therein. A spoiler unit may include a pair of opposed spoiler elements on either side of the discharge area. One or both main electrodes includes a base portion and a center portion which may be a nipple protruding from the base portion. The center portion substantially carries the periodic discharge current such that the discharge width is and may be significantly less than the width of the base portion.

Abstract: A visible light alignment system mounted on a line narrowing module of a UV laser. The system includes an alignment platform on which a small visible light laser is mounted and beam directing optics to direct the visible light beam to reflect off an illumination surface of a first prism in a prism beam expander at an angle such that the visible light beam proceeds collinearly with the UV laser output beam.

Abstract: A line-narrowed excimer or molecular fluorine laser system includes a gain medium surrounded by a resonator for generating a laser beam, a discharge circuit including a plurality of electrodes for energizing the gain medium and a line-narrowing unit within the resonator for narrowing the bandwidth of the laser system. The resonator includes a deformable resonator reflector. A technique for adjusting the bandwidth of the laser system includes adjusting a surface contour of the deformable resonator reflector. A desired bandwidth may be selected manually or using a processor which automatically controls the surface contour adjustment.

Abstract: To reduce the cross-sectional area of a discharge circuit loop in the excitation circuit of a gas laser device that discharges ultraviolet rays, thereby reducing the inductance and enhancing the laser oscillation efficiency, the gas laser device is provided with a laser chamber (1) in which laser gas is sealed and which has a circulation means that circulates the laser gas within the chamber, a pair of main discharge electrodes (3, 4) disposed at a prescribed separation within said laser chamber (1), a discharge circuit having peaking capacitors (C3) that are connected in parallel with the pair of main discharge electrodes (3, 4,) and a preionization unit (15) in which a first electrode (9) and a second electrode (7) are disposed facing each other with a dielectric (8) interposed between them, the preionization unit (15) being disposed running along each side of one of the main discharge electrodes (4), that one of the main discharge electrodes (4) and the peaking capacitors (C3) being connected via a conduct

Abstract: To provide an ArF excimer laser device capable of a pulsewidth FWHM of 20 ns or more, a pulse duration time of 50 ns or more, and a spectrum line width FWHM of 0.35 pm or less, and to provide a KrF excimer laser device and a fluorine laser device with stretched pulse widths. The ArF excimer laser device connects to the output terminal of a magnetic pulse compression circuit and has a pair of laser discharge electrodes located within the laser chamber and a peaking capacitor connected in parallel with the pair of laser discharge electrodes. The output waveform of the laser pulse has a bifurcated form with a front half peak and a later half peak and, if the peak value of the front half peak is P1 and the peak value of the later half peak is P2 and the (proportion of the pulse later half peak)=P2/(P1+P2)×100(%), then the (proportion of the pulse later half peak) is 50% or more.

Abstract: An apparatus and method are provided for bandwidth narrowing of an excimer laser to &Dgr;&lgr;≈6 pm or less with high spectral purity and minimized output power loss. Output stability with respect to pulse energy, beam pointing, beam size and beam output location is also provided. The excimer laser includes an active laser medium for generating a spectral beam at an original wavelength, means for selecting and narrowing the broadband output spectrum of the excimer laser, a resonator having at least one highly reflecting surface, and an output coupler. Means for adapting a divergence of the resonating band within the resonator is further included in the apparatus of the invention. The divergence adapting causes the spectral purity to improve by between 20% and 50% and the output power to reduce by less than 10%. A method according to the invention includes selecting and aligning the divergence adapting means.

Abstract: Excimers are generated by directing an electron beam at about 5 KeV to about 40 KeV into an excimer forming gas such as He, Ne, Ar, Kr, and Xe or mixtures of these with other gases through a ceramic foil such as SiNx. Vacuum ultraviolet (VUV) light is emitted by the excimers or by other species in contact therewith. The invention can provide intense, continuously operable broadband or monochromatic VUV light sources.

Abstract: An excimer laser oscillation apparatus comprises a laser chamber for storing a laser gas, a pair of electrodes arranged in the chamber, and a voltage application circuit for applying a voltage to the pair of electrodes to excite the laser gas. A fluorine passivation film is formed on an inner surface of said laser chamber. The excimer laser apparatus further has a circuit for applying a voltage to the pair of electrodes to flow a current that exceeds a light-emission threshold value between the pair of electrodes while alternately changing a flowing direction thereof. And, the pair of electrodes have an oxygen content of not more than 10 ppm.

Abstract: A wavelength calibration system determines an absolute wavelength of a narrowed spectral emission band of an excimer or molecular laser system. The system includes a module including an element which optically interacts with a component of an output beam of the laser within the tunable range of the laser system around the narrowed band. An inter-level resonance is detected by monitoring changes in voltage within the module, or photo-absorption is detected by photodetecting equipment. The absolute wavelength of the narrowed band is precisely determinable when the optical transitions occur and are detected. When the system specifically includes an ArF-excimer laser chamber, the module is preferably a galvatron containing an element that photo-absorbs around 193 nm and the element is preferably a gas or vapor selected from the group consisting of arsenic, carbon, oxygen, iron, gaseous hydrocarbons, halogenized hydrocarbons, carbon-contaminated inert gases, germanium and platinum vapor.

Abstract: A laser is provided having a gain medium including a laser gas and a photoabsorbing species. The photoabsorbing species has at least one photoabsorption line within an output emission spectrum of the laser. When the laser is an ArF-excimer laser, the photoabsorbing species is preferably either atomic carbon or molecular oxygen, which are formed after carbon- or oxygen-containing molecules introduced into the gain medium with the laser gas interact within the gain medium. An absolute wavelength of a narrowed emission of the laser can be calibrated when a narrowed output emission of the laser is tuned through at least one photoabsorption line of the photoabsorbing species. Preferably, a processor communicates with a detector and a wavelength selection unit, as well as a power supply when output beam energy is held constant, to automatically perform the calibration.

Abstract: The invention relates to a semiconductor exposure ArF excimer laser device having a narrow line width containing 95% of the energy of 1.15 pm or less while using an optical system of prior art beam expansion prisms and a diffraction grating. The ArF excimer laser device for narrowing the bandwidth has a line-narrowing optical system formed of an echelle diffraction grating (3) in a Littrow arrangement, a beam expansion prism system composed of at least three prisms arranged on the incident side of the echelle diffraction grating, and slits 4. The blaze angle (&thgr;) of the diffraction grating 3 is 82° or less, the magnification rate M of the beam expansion prism system is 26 times or less, the oscillation pulse width T1S is 60 ns or less, the length L of the resonator is in a range of 1000 to 1350 mm and the slit width W is 1.

Abstract: A line-narrowed excimer or molecular fluorine laser system includes a gain medium surrounded by a resonator for generating a laser beam, a discharge circuit including a plurality of electrodes for energizing the gain medium and a line-narrowing unit within the resonator for narrowing the bandwidth of the laser system. The resonator includes a deformable resonator reflector. A technique for adjusting the bandwidth of the laser system includes adjusting a surface contour of the deformable resonator reflector. A desired bandwidth may be selected manually or using a processor which automatically controls the surface contour adjustment.

Abstract: An ArF excimer laser device and a fluoride laser device for exposure which is structured so that primary current that infuses energy from a magnetic pulse compression circuit to discharge electrodes via a peaking capacitor overlaps secondary current that infuses energy from the capacitor in the final stage of the magnetic pulse compression circuit to the discharge electrodes, the oscillation cycle of the secondary current is set longer than the oscillation cycle of the primary current, and a pulse of laser oscillation operation is effected by the initial half-cycle of the discharge oscillation current waveform that reverses the polarity of the primary current being overlapped by the secondary current and by at least two half-cycles continuing thereafter, as a result of which a high repetition rate, pulse stretch, line-narrowed ArF excimer laser device and fluorine laser device can be implemented at repetition rate exceeding 2 kHz.

Abstract: A gas mixture of a gas discharge laser such as an excimer or molecular fluorine laser is stabilized. The gas mixture of the laser includes a constituent halogen containing molecular species such as F2 or HCl which is subject to depletion from an initial optimum concentration. When the gas mixture is energized by a pulsed discharge circuit, the amplified spontaneous emission (ASE) signal is monitored. The status of the gas mixture is determined based on the monitored ASE signal. Stimulated emission is preferably filtered or blocked for more precise ASE signal monitoring. The gas mixture is preferably replenished using small halogen injections, total pressure adjustments and mini and partial gas replacements based on the evolving gas mixture status determined from the monitored ASE signal.

Abstract: A technique of stabalizing during operation a gas mixture with a gas composition initially provided within a discharge chamber of an excimer or molecular fluorine gas discharge laser includes monitoring a temporal pulse shape of the laser beam and adjusting and/or determining the status of the gas mixture based on the monitored temporal pulse shape. The monitored temporal pulse shape is preferably compared with a reference temporal pulse shape. The difference or deviation between the monitored temporal pulse shape and a reference temporal pulse shape is calculated. The amount of and intervals between gas replenishment actions are determined based on the calculated deviation. The energy of the beam is also monitored and the driving voltage and gas actions are adjusted to stabilize the energy, energy stability and/or energy dose.

Abstract: A high pulse rate pulse power source for supplying controlled high energy electrical pulses at rates of 2000 Hz or greater. The source includes a pulse generating circuit including a charging capacitor, a solid state switch and a current limiting inductor. Pulses generated in the pulse generating circuit are compressed in at least two pulse compression circuits and a step-up pulse transformer increases peak voltage to at least 12,000 volts. A very fast regulated power supply is provided for charging the charging capacitor in less than 400 microseconds and a pulse control system including a programmed processor controls the charging of the charging capacitor to an accuracy of less than about one percent at a rate of at least 4000 charges per second. In a preferred embodiment capable of operating at pulse rates of 2000 to 4000 Hz or greater, water cooling of the saturable inductors is provided.

Abstract: An F2 laser having an etalon-based line narrowing output coupler and a technique for tuning the laser. The etalon based output coupler is adjusted to preferentially reflect a percentage of light at or near the spectral maximum of one of the primary F2 spectral lines and to not reflect light at the other primary F2 spectral line. Thus, a selected range of the selected line is preferentially amplified in the gain medium and the other line is transmitted out of the laser cavity and, therefore, receives no amplification and is suppressed. The result is substantial narrowing in the preferred embodiment of the 157.630 nm line and effective suppression of the 157.523 nm line. Substantial improvement in line narrowing of 157.630 nm line results from a wavelength selective properties of etalon based line-narrowing output coupler.

Abstract: An excimer laser system with a real time fluorine monitor and an automatic fluorine control system to permit precise control of the fluorine concentration within the laser chamber. Cleaned laser gas is extracted from the laser chamber and directed through an F2 sample cell prior to returning to the chamber through one of the chamber window housings. A UV light beam is directed through the F2 sample cell and the amount of absorption of the light is measured. In preferred embodiments the absorption is measured by detecting with a photo detector the amount of light which passes through the cell. The photo detector provides a feedback signal which is used by a laser controller to automatically control fluorine concentration in the chamber to within desired ranges. In another preferred embodiment an acoustic detector detects acoustic signals resulting from absorbed light pulses. This invention provides a substantially real time measurement of fluorine concentration.

Abstract: A method and apparatus are provided for delivering a laser beam from a laser, such as an F2 laser, to a target through a sealed enclosure. The enclosure is evacuated and back-filled with an inert gas repeatedly for a number of times sufficient to adequately deplete any air, water, hydrocarbons or oxygen within the enclosure. Thereafter, an inert gas flow is established and maintained within the enclosure during operation of the laser. Propagation with significant transmittance of a sub-200 nm beam through the enclosure is particularly enabled.

Abstract: A coherent multiple beam laser system including a plurality of slab lasers and a feedback device responsive to the output of at least one of the slab lasers, for feeding back a portion of the slab laser output to the remaining slab lasers for synchronizing the phase of the outputs of all the slab lasers.

Abstract: A laser apparatus comprises a plurality of laser beam sources which use, as laser media, mixed gases containing at least one common gas component; at least one common gas supply source for supplying, to the respective laser beam sources, the common gas component for constituting the mixed gases; and one or more gas flow amount-adjusting units for adjusting flow amounts of the common gas component supplied from the common gas supply source and other gas components for constituting the mixed gases so that the gas components are supplied to the respective gas laser beam sources. It is unnecessary to provide gas tanks for each of the laser beam sources. The arrangement of the gas supply equipment is simplified, and the safety is improved. A plurality of the laser apparatuses are preferably installed to a circuit element production line provided with a plurality of exposure apparatuses.

Abstract: An excimer laser generating system includes a laser chamber whose inner surface is covered with a fluorine-passivated surface. Preferably, the surfaces of a blower and heat exchanger disposed in the laser chamber are also covered with a fluorine-passivated surface. The fluorine-passivated surface may be formed of a wide variety of materials including an aluminum oxide film, a fluoride film containing aluminum fluoride and magnesium fluoride, iron fluoride, and nickel fluoride. Preferably, the excimer laser generation system includes a gas supply system having an inert gas purging system so that gas sources can be replaced without exposing the inside of gas supply pipes to atmosphere. With the above arrangement, the excimer laser generating system can generate a laser beam pulse whose energy and shape are maintained constant for a long period of operation time without encountering serious degradation.

Abstract: A method is provided for determining the status of a gas mixture of a laser system including a gas discharge laser which generates an output beam and has a discharge chamber containing a gas mixture within which energy is supplied to the gas mixture by a power supply via application of a driving voltage to a discharge circuit. A master data set of an output parameter such as any of output beam energy, bandwidth, spectrum width, long axial beam profile, short axial beam profile, beam divergence, energy stability, energy efficiency, width of the discharge, temporal beam coherence, spatial beam coherence, spatial pulse width, amplified spontaneous emission and temporal pulse width versus an input parameter such as driving voltage is generated corresponding to an optimal gas mixture status, preferably after a new fill and typically at the factory, and alternatively following a new fill at the fab.

Abstract: A smart laser having automatic computer control of pulse energy, wavelength and bandwidth using feedback signals from a wavemeter. Pulse energy is controlled by controlling discharge voltage, wavelength by controlling the position of an RMAX mirror in a line narrowing module and bandwidth is controller by adjusting the curvature of a grating in the line narrowing module. Preferred embodiments include automatic feedback control of horizontal and vertical beam profile by automatic adjustment of a prism plate on which beam expander prisms are located and automatic adjustment of the RMAX tilt.

Abstract: A feedthrough structure of a gas discharge laser chamber conducts electric power through the wall of a sealed gas enclosure to a single piece electrode inside the enclosure. The feedthrough structure includes a single piece integrated main insulator larger than the electrode. The main insulator is compressed between the electrode and the wall of the enclosure. The surfaces forming interfaces between the electrode and the single piece insulator are the insulator and the wall are all very smooth to permit the parts to expand and contract as the chamber temperature varies. The feedthrough structure also provides mechanical support and alignment for the electrode and includes seals to prevent gas leakage around the feedthrough structure.

Abstract: A tangential fan, configured to recirculate a lasing gas mixture, has blade members, which are twisted in a substantially helical fashion about the rotation axis of the fan. The circumferential number of blade members can be constant variable between the end flanges. The circumferential position of blade members can shift monotonically or reversibly between the two ends. A tangential fan in accordance with the invention can be made using a conventional method of brazing together individually stamped and formed blade members and hub members. Finishing processes typically include post-machining, electropolishing, and electroless nickel coating.

Abstract: A smart laser having automatic computer control of pulse energy, wavelength and bandwidth using feedback signals from a wavemeter. Pulse energy is controlled by controlling discharge voltage. Wavelength is controlled by very fine and rapid positioning of an RMAX mirror in a line narrowing module. Bandwidth is controller by adjusting the curvature of a grating in the line narrowing module. Preferred embodiments include automatic feedback control of horizontal and vertical beam profile by automatic adjustment of a prism plate on which beam expander prisms are located and automatic adjustment of the RMAX tilt. Other preferred embodiments include automatic adjustment of the horizontal position of the laser chamber within the resonance cavity. In preferred embodiments, feedback signals from a wavelength monitor are used to position the RMAX mirror. In other preferred embodiments a separate laser beam reflected off the RMAX mirror on to a photodiode array is used to position the mirror.

Abstract: The present invention provides a very narrow band pulse excimer laser capable of producing pulses at a rate in the range of about 500 to 2000 Hz with enhanced energy dose control and reproducibility. Very small quantities of a stablizing additive consisting of oxygen or a heavy noble gas (xenon or radon for KrF lasers, or krypton, xenon or radon for ArF lasers), are added to the gas mixture. Tests performed show substantial improvements in energy stability with the addition of about 30 ppm of xenon to a KrF laser. Tests show improved performance for the ArF lasers with the addition of about 6-10 ppm of Xe or 40 ppm of Kr. In a preferred embodiment very narrow bandwidth is achieved on a KrF laser by reducing fluorine partial pressure to less than 0.10 percent and by increasing the reflectance of the output coupler to greater than 25 percent. In a preferred embodiment, prior art fused silica beam expansion prisms used in the prior art line-narrowing module were replaced with calcium fluoride prisms.

Abstract: A support bar member for supporting an electrode member of a pulsed laser system is described. The support bar member includes an aerodynamic nose configured to reduce an aerodynamic load applied against a blower assembly of the laser system by the support bar member. The nose provides an aerodynamic cut-off region on the support bar member such that, when the blower assembly is operating, the blower assembly does not vibrate significantly.

Abstract: A narrow-band oscillation excimer laser has optics which are excellent in durability and light quality, wherein an optical component is a fluoride component (7), and wherein a cleavage plane (20) of the fluoride component (7) is at least substantially parallel with at least one of (a) an incidence side plane (23), for a laser beam (3) entering the fluoride component(7), and (b) an exit side plane (23a), for the laser beam (3) exiting from the fluoride component (7). The fluoride component (7) is positioned in the excimer laser so that the cleavage plane (20) of the fluoride component (7) is at least substantially perpendicular to a light path of the laser beam (3) passing through the inside of the fluoride component (7). A visible mark (27) indicates a direction of the cleavage plane (20).

Abstract: A dual discharge tube excimer laser is provided. An oscillator having a first discharge tube generates a laser beam having a cross-sectional shape as initially defined by the first discharge tube. The oscillator selects a bandwidth of the laser beam and maintains the cross-sectional shape of the laser beam within the oscillator and as it exits the oscillator. The laser beam exiting the oscillator is amplified by one pass through the first discharge tube and two passes through a second discharge tube.