Abstract: A discharge-pumped excimer laser device has a casing, a pair main discharge electrodes, a cross-flow fan for producing a high-speed laser gas flow between the main discharge electrodes, the cross-flow fan having a rotatable shaft projecting from opposite ends thereof, magnetic bearings, the rotatable shaft being rotatably supported by the bearings, protective bearings for supporting the rotatable shaft when the magnetic bearings are not in operation, and a motor for actuating the cross-flow fan. The magnetic bearings include radial magnetic bearings disposed on the opposite ends of the rotatable shaft. One of the radial magnetic bearings which is disposed closely to the motor has a bearing rigidity greater than the bearing rigidity of the magnetic bearing that is disposed remotely from the motor.

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: The present invention provides an injection seeded modular gas discharge laser system capable of producing high quality pulsed laser beams at pulse rates of about 4,000 Hz or greater and at pulse energies of about 5 to 10 mJ or greater for integrated outputs of about 20 to 40 Watts or greater. Two separate discharge chambers are provided, one of which is a part of a master oscillator producing a very narrow band seed beam which is amplified in the second discharge chamber. The parameters chamber can be controlled separately permitting optimization of wavelength parameters in the master oscillator and optimization of pulse energy parameters in the amplifying chamber. A preferred embodiment is a F2 laser system configured as a MOPA and specifically designed for use as a light source for integrated circuit lithography. In this preferred embodiment, both of the chambers and the laser optics are mounted on a vertical optical table within a laser enclosure.

Abstract: The present invention provides an excimer laser capable of producing a high quality pulsed laser beam at pulse rates of about 4,000 Hz at pulse energies of about 5 mJ or greater. A preferred embodiment is an ArF excimer laser specifically designed as a light source for integrated circuit lithography. An improved wavemeter with special software monitors output beam parameters and controls a very fast PZT driven tuning mirror and the pulse power charging voltage to maintain wavelength and pulse energy within desired limits. In a preferred embodiment two fan motors drive a single tangential fan which provides sufficient gas flow to clear discharge debris from the discharge region during the approximately 0.25 milliseconds between pulses.

Abstract: An ArF excimer laser device for performing an oscillating operation with a repetition rate of more than 3 kHz and an oscillating laser pulse width (Tis) of more than 30 ns. The laser operation is carried out in an initial half-period of an electrical discharge oscillating current waveform of a pulse of reversed polarity generated by a high voltage pulse generating device and in at least two subsequent half-periods. The pressure of the laser gas in the laser chamber is 2.5 to 3.5 atm, the fluorine concentration is 0.12% or less, and the argon gas concentration 3% or less. As a result, the laser pulse width (Tis) can be set to more than 30 ns.

Abstract: An orifice (254) is disposed near the junction of a discharge tube (1) and a laser gas lead-in pipe (242). A laser gas relay pipe (244) is disposed so as to allow the laser gas to flow parallel in the same direction as or in the reverse direction to the flowing direction of laser gas in the discharge tube (1). The orifice (254) includes a portion for impeding flow of laser gas, and plural holes for passing laser gas, and at least one of the holes is deviated from the center. The total area of the holes summing up the area of the plural holes provided in the orifice (254) is at a rate of 0.5 to 0.8 to the sectional area of the discharge tube. The plural holes of the orifice (254) are nearly circular, and the diameter of each hole is smaller than the radius of the orifice.

Abstract: A molecular fluorine (F2) laser system includes a seed oscillator and power amplifier. The seed oscillator includes a laser tube including multiple electrodes therein which are connected to a discharge circuit. The laser tube is part of an optical resonator for generating a laser beam including a first line of multiple characteristic emission lines around 157 nm. The laser tube is filled with a gas mixture including molecular fluorine and a buffer gas. A low pressure seed radiation generating gas lamp is alternatively used. The gas mixture is at a pressure below that which results in the generation of a laser emission including the first line around 157 nm having a natural linewidth of less than 0.5 pm. The power amplifier amplifies the power of the beam emitted by the seed oscillator to a desired power for applications processing.

Abstract: An efficient F2 laser is provided with improvements in line selection, monitoring capabilities, alignment stabilization, performance at high repetition rates and polarization characteristics. Line selection is preferably provided by a transmission grating or a grism. The grating or grism preferably outcouples the laser beam. The line selection may be fully provided at the front optics module. A monitor grating and an array detector monitor the intensity of the selected (and unselected) lines for line selection control. An energy detector is enclosed in an inert gas purged environment at slight overpressure. A blue or green reference beam is used for F2 laser beam alignment stabilization and/or spectral monitoring of the output laser beam. The blue or green reference beam advantageously is not reflected out with a atomic fluorine red emission of the laser and is easily resolved from the red emission.

Abstract: An excimer laser device capable of suppressing vibration of a cross flow fan, and preventing breakage of magnetic bearings when the vibration increases is provided. For this purpose, the device has a configuration that in the excimer laser device including magnetic bearings (12) each having an inner ring section (10, 30) and an outer ring section (11, 31), and a cross flow fan (1) for circulating a laser gas in a chamber (2), touch-down bearings (15) are provided on the outer peripheral side of a rotating shaft (9), and the inner peripheral face of an inner peripheral portion (15B) of the touch-down bearing (15) and the outer peripheral face of the rotating shaft (9) are disposed opposite each other with a predetermined clearance smaller than a gap (4) between the outer peripheral face of the inner ring section (10, 30) and the inner peripheral face of the outer ring section (11, 31).

Abstract: A gas laser device including a dust filter with which a flow rate of laser gas flowing between discharge electrodes is approximately uniform in a longitudinal direction of the discharge electrodes without a variation with time is provided. For this purpose, the gas laser device includes a laser chamber (2) containing laser gas, a pair of discharge electrodes (5, 5) disposed inside the laser chamber (2) to face to each other for exciting a laser medium by discharge to thereby oscillate laser light, a fan (14) for circulating the laser gas to send the same to an area between the discharge electrodes (5, 5), and a dust filter (12) for eliminating dust generated inside the laser chamber (2), and has a configuration in which a filter inlet port (15), which is formed in an inner wall (2A) of the laser chamber (2) and guides the laser gas into the dust filter (12), is formed to be approximately vertical to the inner wall (2A) of the laser chamber (2).

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: An injection seeded modular gas discharge laser system capable of producing high quality pulsed laser beams at pulse rates of about 4,000 Hz or greater and at pulse energies of about 5 mJ or greater. Two separate discharge chambers are provided, one of which is a part of a master oscillator producing a very narrow band seed beam which is amplified in the second discharge chamber. The chambers can be controlled separately permitting separate optimization of wavelength parameters in the master oscillator and optimization of pulse energy parameters in the amplifying chamber. A preferred embodiment in an ArF excimer laser system configured as a MOPA and specifically designed for use as a light source for integrated circuit lithography. In the preferred MOPA embodiment, each chamber comprises a single tangential fan providing sufficient gas flow to permit operation at pulse rates of 4000 Hz or greater by clearing debris from the discharge region in less time than the approximately 0.25 milliseconds between pulses.

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: The present invention provides an ultra pure purge system for discharge lasers. The LNP, the output coupler, the wavemeter and selected high voltage components are contained in sealed chambers each having a purge inlet port and a purge outlet port. Purge gas such as N2 is filtered and directed to each of the inlet ports. Gas exiting the outlet ports may be directed to flow monitors having alarms so that any loss of purge will be immediately detected. Purge gas may be exhausted or recirculated.

Abstract: The present invention provides a discharge-pumped excimer laser device which includes a laser chamber filled with a laser gas that is deteriorated to a small extent, magnetic bearings and a motor that are resistant to the entry of dust particles, and parts that are held in contact with the laser gas and suffer little damage, and has a long service life.

Abstract: An excimer laser device which neither corrodes due to a laser gas nor contaminates the laser gas is provided. For this purpose, in an excimer laser device including a cross flow fan (1) disposed in a chamber (2) for circulating a laser gas, magnetic bearings (12, 12) having outer ring magnet coils (11, 11) and inner ring magnetic substances (10, 10) for rotatably supporting a rotating shaft (9) by magnetic force, and a motor (49) having a stator (47) and a rotor (48) for directly and rotationally driving the cross flow fan (1), the outer ring magnet coils (11, 11), the inner ring magnetic substances (10, 10), the rotor (48), and the stator (47) are respectively housed in shielded spaces shielded from the laser gas.

Abstract: In an excimer laser apparatus comprising a laser chamber 1 filled with a laser gas, a discharge excitation portion 2 provided in the laser chamber 1, a rotary shaft 3 to which a gas circulating fan 4 for circulating the laser gas is fixed, a shield partition wall 61 for forming a sealed space to enclose the rotary shaft 3, a magnetic bearing of a control type including a rotor portion 32 provided on the rotary shaft 3 side and a stator portion 6 provided outside the shield partition wall 61 and serving to pivotally support the rotary shaft 3 in non-contact, a driving motor 13 provided outside the laser chamber 1, magnetic coupling portions 33, 11 and 121 for transmitting driving force of the driving motor 13 to the rotary shaft 3 through the shield partition wall 61 in non-contact, and rotary shaft sensors 8 and 9 for detecting a position of the rotor portion 32 with respect to the stator portion 6.

Abstract: In a gas circulation fan, a main shaft is supported in a non-contact manner, by magnetic bearings. Between each of the magnetic bearings and a controller, a relay is provided. Each relay includes a position detection sensor circuit, an offset adjuster, a feedback gain adjuster and a filter circuit. Thus, compatibility between a mechanical body unit and the controller is attained.

Abstract: An efficient and practical means and method is provided for monitoring the F2 concentration in an F2 excimer laser. The F2 concentration is monitored by measuring the concentration F atoms and more specifically by measuring the amount of red laser light emitted during discharge. The amount of red laser light emitted during discharge is a function of the concentration of F atoms because such red laser light is emitted by excited F atoms. There is also a relationship between the concentration of F atoms and the concentration of molecular F2 in the discharge chamber. Accordingly, the concentration of F2 gas may be monitored by measuring the amount of red laser light emitted during discharge.

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 magnetic bearing enables to rotatably support a levitated body non-contactingly disposed in a hermetically sealed container filled with a gaseous process substance of a corrosive nature, while without contaminating the gaseous environment and suffering from corrosion. The magnetic bearing has an electromagnet for supporting a levitated body, a displacement sensor for detecting a levitated position of the levitated body, and a controller for supplying signals and excitation currents to the displacement sensor and the electromagnet through cables. An electromagnet target of the magnetic bearing that generates variations in magnetic fields due to rotation of the levitated body, is constructed of a single piece of ferromagnetic material, and is provided with an electrical insulation structure oriented parallel to magnetic fluxes generated by the electromagnet.

Abstract: A method and apparatus is provided for stabilizing output beam parameters of a gas discharge laser by maintaining a constituent gas of the laser gas mixture at a predetermined partial pressure using a gas supply unit and a processor. The constituent gas of the laser gas mixture is provided at an initial partial pressure and the constituent gas is subject to depletion within the laser discharge chamber. Injections of the constituent gas are performed each to increase the partial pressure by a selected amount in the discharge chamber preferably less than 0.2 mbar per injection. A number of successive injections is performed at selected intervals to maintain the constituent gas substantially at the initial partial pressure for maintaining stable output beam parameters. The amount per injection and/or the interval between injections may be varied based on the measured value of the driving voltage and/or a calculated amount of the constituent gas in the discharge chamber.

Abstract: A laser component purge system for discharge lasers. The LNP, the output coupler and the wavemeter are contained in sealed chambers each having a purge inlet port and a purge outlet port. Purge gas such as N2 is directed to each of the inlet ports. A purge monitoring system is provided which monitors the purge flow and provides one or more signals to a processor which is programmed to minimize laser timeouts attributable to purge conditions without endangering the purged optical components. In a preferred embodiment, gas exiting the outlet ports are directed to flow monitors which provide the one or more signals to the processor. Purge gas may be exhausted or recirculated.

Abstract: A method and apparatus is provided for stabilizing output beam parameters of a gas discharge laser by maintaining a constituent gas of the laser gas mixture at a predetermined partial pressure using a gas supply unit and a processor. The constituent gas of the laser gas mixture is provided at an initial partial pressure and the constituent gas is subject to depletion within the laser discharge chamber. Injections of the constituent gas are performed each to increase the partial pressure by a selected amount in the discharge chamber preferably less than 0.2 mbar per injection. A number of successive injections is performed at selected intervals to maintain the constituent gas substantially at the initial partial pressure for maintaining stable output beam parameters. The amount per injection and/or the interval between injections may be varied based on the measured value of the driving voltage and/or a calculated amount of the constituent gas in the discharge chamber.

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: A narrow band molecular fluorine laser system includes an oscillator and an amplifier, wherein the oscillator produces a 157 nm beam having a linewidth less than 1 pm and the amplifier increases the power of the beam above a predetermined amount, such as more than one or several Watts. The oscillator includes a discharge chamber filled with a laser gas including molecular fluorine and a buffer gas, electrodes within the discharge chamber connected to a discharge circuit for energizing the molecular fluorine, and a resonator including the discharge chamber for generating a laser beam having a wavelength around 157 nm. Line-narrowing optics are included intra- and/or extra-resonator for reducing the linewidth of the laser beam to less than 1 pm. The amplifier may be the same or a different discharge chamber, and optical and/or electronic delays may be used for timing pulses from the oscillator to reach the amplifier at a maximum in the discharge current of the amplifier.

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: A beam delivery system for a laser emitting at a relevant wavelength of less than 200 nm is provided. The system includes a sealed enclosure connected to the laser and surrounding the path of the beam as it exits the laser resonator. The enclosure extends between the laser output coupler and a photodetector sensitive at the wavelength of the relevant laser emission. The interior of the enclosure, and thus the beam path between the output coupler and the detector, is substantially free of species that strongly photoabsorb radiation at the relevant laser emission wavelength. A beam splitting element diverts at least a portion of the beam for measurement by the detector. The beam splitting element preferably includes a beam splitting mirror, holographic beam sampler or diffraction grating. In addition, optics are preferably provided for filtering a visible portion of the diverted beam, so that substantially only a VUV portion of the diverted beam is received at the detector.

Abstract: A gas discharge laser capable of operating at pulse rates in the range of 4,000 Hz to 6,000 Hz at pulse energies in the range of 5 mJ to 10 mJ or greater. Important improvements over prior art designs include: (1) a squirrel cage type fan for producing gas velocities through the discharge region of more than 67 m/s and capable of continuous trouble-free operation for several months, (2) a liquid cooled drive motor having a low loss sealing member separating the motor rotor from the motor starter and protecting the motor from the laser gas and a breach detection device for detecting any breach of the sealing member, (3) a heat exchanger system capable of removing in excess of 16 kw of heat energy from the laser gas and (4) a pulse power system capable of providing precisely controlled electrical pulses to the electrodes needed to produce laser pulses at the desired pulse energies in the range of 5 mJ to 10 mJ or greater at pulse repetition rates in the range of 4,000 Hz to 6,000 Hz or greater.

Abstract: A gas laser gas has an elongated cavity in which are disposed a first elongated electrode tube having an inner diameter, and a second elongated electrode tube disposed coaxially within the first electrode tube and having an outer diameter smaller than the inner diameter of the first electrode tube and spaced therefrom so as to provide a gas discharge chamber therebetween. The second electrode tube provides a gas exit chamber therewithin, and the first electrode tube is spaced from the wall of the cavity to provide a gas entry chamber thereabout. The electrode tubes permit gas to flow therethrough from the gas entry chamber to the gas exit chamber. The electrodes may be formed from a gas permeable material such as sintered metal, or formed from a non-permeable material with openings therein. The electrodes may have coolant flowing therethrough.

Abstract: A gas discharge modular laser with beam train isolation between laser chamber module and front and rear optics which define the laser resonant cavity. Beam train isolation units isolates the beam train from atmospheric air while permitting quick and easy removal of the laser chamber without disturbing the optics of the resonant cavity. In preferred embodiments, metal bellows units are bolted at only side so that the chamber module can be removed and replaced without unbolting the bellows unit.

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 beam delivery system for a laser emitting at a relevant wavelength of less than 200 nm is provided. The system includes a sealed enclosure connected to the laser and surrounding the path of the beam as it exits the laser resonator. The enclosure extends between the laser output coupler and a photodetector sensitive at the wavelength of the relevant laser emission. The interior of the enclosure, and thus the beam path between the output coupler and the detector, is substantially free of species that strongly photoabsorb radiation at the relevant laser emission wavelength. A beam splitting element diverts at least a portion of the beam for measurement by the detector. The beam splitting element preferably includes a beam splitting mirror, holographic beam sampler or diffraction grating. In addition, optics are preferably provided for filtering a visible portion of the diverted beam, so that substantially only a VUV portion of the diverted beam is received at the detector.

Abstract: An all gas phase iodine cw laser operating on the electronic I(2P3/2)−I*(2P1/2) transition of atomic iodine at 1.315 &mgr;m was described. The laser is based on the energy transfer reaction between metastable NCl(a1&Dgr;) and ground state I(2P3/2) atoms. This all gas phase laser has a number of advantages over previous aqueous-based chemical oxygen iodine lasers, including lighter weight, zero-gravity operation, and heat rejection in the exhaust.

Abstract: A method and apparatus is provided for stabilizing output beam parameters of a gas discharge laser by maintaining a constituent gas of the laser gas mixture at a predetermined partial pressure using a gas supply unit and a processor. The constituent gas of the laser gas mixture is provided at an initial partial pressure and the constituent gas is subject to depletion within the laser discharge chamber. Injections of the constituent gas are performed each to increase the partial pressure by a selected amount in the discharge chamber preferably less than 0.2 mbar per injection. A number of successive injections is performed at selected intervals to maintain the constituent gas substantially at the initial partial pressure for maintaining stable output beam parameters. The amount per injection and/or the interval between injections may be varied based on the measured value of the driving voltage and/or a calculated amount of the constituent gas in the discharge 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 method and apparatus is provided for stabilizing output beam parameters of a gas discharge laser by maintaining a constituent gas of the laser gas mixture at a predetermined partial pressure using a gas supply unit and a processor. The constituent gas of the laser gas mixture is provided at an initial partial pressure and the constituent gas is subject to depletion within the laser discharge chamber. Injections of the constituent gas are performed each to increase the partial pressure by a selected amount in the discharge chamber preferably less than 0.2 mbar per injection. A number of successive injections is performed at selected intervals to maintain the constituent gas substantially at the initial partial pressure for maintaining stable output beam parameters. The amount per injection and/or the interval between injections may be varied based on the measured value of the driving voltage and/or a calculated amount of the constituent gas in the discharge chamber.

Abstract: A method and apparatus is provided for stabilizing output beam parameters of a gas discharge laser by maintaining a constituent gas of the laser gas mixture at a predetermined partial pressure using a gas supply unit and a processor. The constituent gas of the laser gas mixture is provided at an initial partial pressure and the constituent gas is subject to depletion within the laser discharge chamber. Injections of the constituent gas are performed each to increase the partial pressure by a selected amount in the discharge chamber preferably less than 0.2 mbar per injection. A number of successive injections is performed at selected intervals to maintain the constituent gas substantially at the initial partial pressure for maintaining stable output beam parameters. The amount per injection and/or the interval between injections may be varied based on the measured value of the driving voltage and/or a calculated amount of the constituent gas in the discharge 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 gas discharge laser having a laser chamber with two elongated erodable electrode elements, at least one of said electrode element having a generally blunt blade-shaped portion comprised of a material having high electrical conductivity with a flow shaping dielectric fairing positioned on each of two sides of said blunt blade-shaped portion. A pulse power system provides electrical pulses at rates of at least 1 KHz. A blower circulates laser gas between the electrodes at speeds of at least 10 m/s and a heat exchanger is provided to remove heat produced by the blower and the discharges.

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 photo-absorbing 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: An excimer laser apparatus comprises a container sealing a laser gas including a halogen gas therein, a pair of discharge electrodes disposed in the container for inducing an electric discharge capable of oscillating a laser light, and a circulating fan with a shaft for producing a high-speed laser gas stream between a pair of the discharge electrodes. Both ends of the shaft are rotatably supported by rotor-stator mechanisms, or one end of the shaft is rotatably supported by a rotor-stator mechanism, and the other end of the shaft is supported by a magnetic bearing. The rotor-stator mechanism comprises a rotor attached to the shaft of the circulating fan, a stator provided at a position opposed to the rotor, an electric motor winding provided in the stator for applying torque to the rotor, and a position control winding provided in the stator for producing a magnetic force to levitate and support the rotor.

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 method and apparatus is provided for stabilizing output beam parameters of a gas discharge laser by maintaining a constituent gas of the laser gas mixture at a predetermined partial pressure using a gas supply unit and a processor. The constituent gas of the laser gas mixture is provided at an initial partial pressure and the constituent gas is subject to depletion within the laser discharge chamber. Injections of the constituent gas are performed each to increase the partial pressure by a selected amount in the discharge chamber preferably less than 0.2 mbar per injection. A number of successive injections is performed at selected intervals to maintain the constituent gas substantially at the initial partial pressure for maintaining stable output beam parameters. The amount per injection and/or the interval between injections may be varied based on the measured value of the driving voltage and/or a calculated amount of the constituent gas in the discharge chamber.

Abstract: First and second radial magnetic bearings are provided at opposing ends of a rotary shaft, first and second protective bearings are arranged in the vicinity thereof, a third radial magnetic bearing is arranged on a side of a fan near a motor, and by the third radial magnetic bearing, negative spring element of the motor is corrected.

Abstract: A gas discharge laser capable of operating at pulse rates in the range of 4,000 Hz to 6,000 Hz at pulse energies in the range of 5 mJ to 10 mJ or greater. Important improvements over prior art designs include: (1) a squirrel cage type fan for producing gas velocities through the discharge region of more than 67 m/s and capable of continuous trouble-free operation for several months, (2) a liquid cooled drive motor having a low loss sealing member separating the motor rotor from the motor starter and protecting the motor from the laser gas and a breach detection device for detecting any breach of the sealing member, (3) a heat exchanger system capable of removing in excess of 16 kw of heat energy from the laser gas and (4) a pulse power system capable of providing precisely controlled electrical pulses to the electrodes needed to produce laser pulses at the desired pulse energies in the range of 5 mJ to 10 mJ or greater at pulse repetition rates in the range of 4,000 Hz to 6,000 Hz or greater.

Abstract: A tunable injection seeded very narrow band F2 lithography laser. The laser combines modular design features of prior art long life releasable lithography lasers with special F2 line narrowing and tuning techniques applied to a seed beam operated in a first gain medium which beam is used to stimulate narrow band lasing in a second gain medium to produce a very narrow band laser beam useful for integrated circuit lithography.

Abstract: A laser diode is mounted on a plate that fits closely within a mortise in a thermally conductive insert. The insert, in turn, fits closely within a thermally conductive sleeve. The plate has six sides and the laser diode is attached to one of the sides. Heat is conducted away from the remaining five sides of the plate. The insert includes a conic section that fits within a conic section in the sleeve to provide good thermal contact between the insert and the sleeve. The sleeve includes a plurality of holes and contains a fan for circulating air through the sleeve, thereby removing heat from the sleeve. The sleeve includes a cylindrical portion for being held in a hand.

Abstract: A long life laser chamber for a halogen containing gas discharge laser. In a preferred embodiment electrode erosion caused by excited fluorine (i.e., atomic fluorine and fluorine ions) is reduced by forcing the excited fluorine away from the discharge footprint of the electrodes. Preferred embodiments include electrodes with a large number of small holes in the discharge footprint through which laser gas flows to remove the excited fluorine from the footprint region in the time period between electric discharges.

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 or greater. 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. These improvements include an increased capacity high voltage power supply with a voltage bleed-down circuit for precise voltage trimming, an improved communication module that generates a high voltage pulse from the capacitors charged by the high voltage power supply and amplifies the pulse voltage 23 times with a very fast voltage transformer having a secondary winding consisting of a single four-segment stainless steel rod.