Abstract: Output beam parameters of a gas discharge laser are stabilized by maintaining a molecular fluorine component at a predetermined partial pressure using a gas supply unit and a processor. The molecular fluorine is subject to depletion within the discharge chamber. Gas injections including molecular fluorine can increase the partial pressure of molecular fluorine by a selected amount. The injections can be performed at selected intervals to maintain the constituent gas substantially at the initial partial pressure. The amount per injection and/or the interval between injections can be varied, based on factors such as driving voltage and a calculated amount of molecular fluorine in the discharge chamber. The driving voltage can be in one of multiple driving voltage ranges that are adjusted based on system aging. Within each range, gas injections and gas replacements can be performed based on, for example, total applied electrical energy or time/pulse count.

Abstract: A line-narrowing module for a laser includes a prism beam expander and a grating preferably attached to a heat sink. A pressure-controlled enclosure filled with an inert gas seals the grating and/or other elements of the line-narrowing module. The pressure in the enclosure is adjusted for tuning the wavelength. Preferably, the pressure is controlled by controlling the flow of an inert gas through the enclosure. A pump may be used, or an overpressure flow may be used. Alternatively, a prism of the beam expander or an etalon may be rotatable for tuning the wavelength.

Abstract: Output beam parameters of a gas discharge laser are stabilized by maintaining a molecular fluorine component at a predetermined partial pressure using a gas supply unit and a processor. The molecular fluorine is subject to depletion within the discharge chamber. Gas injections including molecular fluorine can increase the partial pressure of molecular fluorine by a selected amount. The injections can be performed at selected intervals to maintain the constituent gas substantially at the initial partial pressure. The amount per injection and/or the interval between injections can be varied, based on factors such as driving voltage and a calculated amount of molecular fluorine in the discharge chamber. The driving voltage can be in one of multiple driving voltage ranges that are adjusted based on system aging. Within each range, gas injections and gas replacements can be performed based on, for example, total applied electrical energy or time/pulse count.

Abstract: A method and apparatus is provided for stabilizing output beam parameters of a gas discharge laser by maintaining a molecular fluorine component of the laser gas mixture at a predetermined partial pressure using a gas supply unit and a processor. The molecular fluorine is provided at an initial partial pressure and is subject to depletion within the laser discharge chamber. Injections of gas including molecular fluorine are performed each to increase the partial pressure of molecular fluorine by a selected amount in the laser chamber preferably less than 0.2 mbar per injection, or 7% of an amount of F2 already within the laser chamber. A number of successive injections may be performed at selected intervals to maintain the constituent gas substantially at the initial partial pressure for maintaining stable output beam parameters.

Abstract: A method and apparatus is provided for stabilizing output beam parameters of a gas discharge laser by maintaining a molecular fluorine component of the laser gas mixture at a predetermined partial pressure using a gas supply unit and a processor. The molecular fluorine is provided at an initial partial pressure and is subject to depletion within the laser discharge chamber. Injections of gas including molecular fluorine are performed each to increase the partial pressure of molecular fluorine by a selected amount in the laser chamber preferably less than 0.2 mbar per injection, or 7% of an amount of F2 already within the laser chamber. A number of successive injections may be performed at selected intervals to maintain the constituent gas substantially at the initial partial pressure for maintaining stable output beam parameters.

Abstract: A method for operating an excimer or molecular fluorine laser system at a stabilized wavelength includes generating a laser beam and directing a beam portion through a wavelength measurement system, calibrating the wavelength measurement system to an absolute reference, determining the wavelength of the laser beam including figuring in a drift compensation value of the wavelength, and tuning the wavelength to a target wavelength when the determined wavelength differs from the target wavelength.

Abstract: An excimer or molecular fluorine laser, such as a KrF- or ArF-laser, or a molecular fluorine (F2) laser, particularly for photolithography applications, has a gas mixture including a trace amount of a gas additive. The concentration of the gas additive in the gas mixture is optimized for improving energy stability and/or the overshoot control of the laser output beam. The concentration is further determined and adjusted at new fills and/or during laser operation based on its effect on the output pulse energy in view of constraints and/or aging on the discharge circuit and/or other components of the laser system. Attenuation control is also provided for increasing the lifetimes of components of the laser system by controlling the concentration of the gas additive over time. A specific preferred concentration of xenon is more than 100 ppm for improving the energy stability and/or overshoot control.

Abstract: An excimer or molecular fluorine laser system generates a laser output bandwidth of less than 0.6 pm, and preferably 0.5-0.4 pm or less. The laser resonator has a line-narrowing unit preferably including a grating, and preferably also a beam expander, and may include one or more etalons or other interferometric devices. The grating may be preferably a blazed grating having a blaze angle greater than 76°, and is preferably around 80°. The grating structure is preferably defined by the surface of the grating substrate. The substrate is preferably aluminum. The system may further include an amplifier for increasing the energy of the sub-0.6 nm output beam.

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 ultraviolet light detection system is provided wherein a dark current background growth rate with total accumulated exposure dose is avoided, and parameters of an ultraviolet radiation source such as an ArF-excimer laser may be monitored without rapid degradation of the signal by the superposition of the dark current background over a desired signal. The invention provides a detector including a light sensitive element having a frequency conversion coating on its surface. The coating is preferably directly on the light sensitive element, absorbing incident ultraviolet light and re-emitting visible light in a direction toward the light sensitive element. The coating minimizes a dark current background that would otherwise appear when incident ultraviolet light impinges directly upon the light sensitive element, and thereby extends a lifetime of the light sensitive element.

Abstract: An ultraviolet light detection system is provided wherein a dark current background growth rate with total accumulated exposure dose is avoided, and parameters of an ultraviolet radiation source such as an ArF-excimer laser may be monitored without rapid degradation of the signal by the superposition of the dark current background over a desired signal. The invention provides a detector including a light sensitive element having a frequency conversion coating on its surface. The coating is preferably directly on the light sensitive element, absorbing incident ultraviolet light and re-emitting visible light in a direction toward the light sensitive element. The coating minimizes a dark current background that would otherwise appear when incident ultraviolet light impinges directly upon the light sensitive element, and thereby extends a lifetime of the light sensitive element.

Abstract: An ultraviolet light detection system is provided wherein a dark current background growth rate with total accumulated exposure dose is avoided, and parameters of an ultraviolet radiation source such as an ArF-excimer laser may be monitored without rapid degradation of the signal by the superposition of the dark current background over a desired signal. The invention provides a detector including a light sensitive element having a frequency conversion coating on its surface. The coating is preferably directly on the light sensitive element, absorbing incident ultraviolet light and re-emitting visible light in a direction toward the light sensitive element. The coating minimizes a dark current background that would otherwise appear when incident ultraviolet light impinges directly upon the light sensitive element, and thereby extends a lifetime of the light sensitive element.

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: Even in the case of variations in the pulse repetition frequency, a solid-state laser generates laser pulses with constant beam characteristics in such a way that when the pulse repetition frequency of the laser pulses is varied the pulse duty factor of the pumping radiation is kept constant and Q switching is triggered in each case at a prescribed period after the start of the pumping pulse.

Abstract: A solid state laser, especially a solid state laser pumped by laser diodes (3b, 3c) comprises a polarizing beam splitter (5) to couple out from the resonant cavity some part (11) of the radiation energy. An electro-optic modulator (Pockels' cell) (4) serving as couple-out modulator is adjusted such that the ratio of the pulse energy of the laser beam pulses (10) emitted to the coupled-out part (11) of the radiation energy is variable and thus the pulse energy is adjustable by keeping the pulse duration constant.

Abstract: A Q-switched solid-state laser has a narrow-band laser diode (18) whose narrow-band output radiation serves as seed radiation for exciting a solid (14), with the result that only a single wavelength-stable longitudinal mode oscillates in the resonator (10, 12) of the solid-state laser and corresponding radiation (16) is emitted.