摘要:
An F2 laser having an etalon-based line narrowing output coupler (164) and a technique for tuning the laser. The etalon based output coupler (165A, 165B) is adjusted to preferentially reflect a percentage (about 17 %) 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.
摘要:
The present invention provides a wavemeter for an ultraviolet laser capable of long life beam quality monitoring in a pulsed ultraviolet laser system at pulse rates greater that 2000 Hz at pulse energies at 5 mJ or greater. In a preferred embodiment an enhanced illumination configuration reduces per pulse illumination of an etalon by a factor of 28 compared to a popular prior art configuration. Optics are provided in this embodiment which reduce light entering the etalon to only that amount needed to illuminate a linear photo diode array positioned to measure interference patterns produced by the etalon. In this preferred embodiment tow sample beams produced by reflections from two surfaces of a beam splitter are diffused by a defractive diffuser and the output of the defractive diffuser is focused on tow separate secondary diffusers effectively combining both beams in two separate secondary diffusers effectively combining both beams in two separate spectrally equivalent diffuse beams. One beam is used for wavelength and bandwidth measurement and the other beam is used for calibration. In preferred embodiments an etalon chamber contains nitrogen with an oxygen concentration of between 1.6 and 2.4 percent.
摘要:
The present invention provides a modular high repetition rate ultraviolet gas discharge laser light source (Fig. 1) with a beam delivery to a production line machine (2). The system includes an enclosed (4) and purged beam path (14C) with a beam pointing control (40A) (40B) (6) for delivery of the laser beam to a desired location such as the entrance port of the production line machine (2). In preferred embodiments, the production line machine is a lithography machine (2) and two separate discharge chambers (8)(10) are provided, one of which is a part of a master oscillator (8) producing a very narrow band seed beam (14A), which is amplified in the second discharge chamber (10). This MOPA system is capable of output pulse energies approximately double the comparable single chamber laser system with greatly improved beam quality.
摘要:
Feedback timing control equipment and process for an injection seeded modular gas discharge laser (11). A preferred embodiment is a 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. The feedback timing control is programmed to permit in some circumstances discharges timed so that no significant laser energy is output from the system. Use of this technique permits burst mode operation in which the first discharge of a burst is a no-output discharge so that timing parameters for each of the two chambers can be monitored before the first laser output pulse of the burst. 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 optimization of wavelength parameters in the master oscillator and optimization of pulse energy parameters in the amplifying chamber.
摘要:
An excimer laser with a purged beam path capable of producing a high quality pulsed laser beam at pulse rates in excess of 2,000 Hz at pulse energies of about 5mJ or greater. The entire purged beam path through the laser system is sealed to minimize contamination of the beam path. A preferred embodiment comprises a thermally decoupled LNP aperture element (70A) to minimize thermal distortions in the LNP (54). This preferred embodiment is an ArF excimer laser specifically designed as a light source for integrated circuit lithography. A wavemeter (7) is provided with a special purge of a compartment exposed to the output laser beam.
摘要:
A narrow band F2 laser system useful for integrated circuit lithography. An output beam from a first F2 laser gain medium (master oscillator) is filtered with a pre-gain filter to produce a seed beam having a bandwidth of about 0.1 pm or less. The seed beam is amplified in a power gain stage which includes a second F2 laser gain medium. The output beam of the system is a pulsed laser beam with a full width half maximum band width of about 0.1 pm or less with pulse energy in excess of about 5 mJ. In a preferred embodiment the pre-gain filter includes a wavelength monitor that permits feedback control over the centreline wavelength so that the pre-gain filter optics can be adjusted to ensure that the desired bandwidth range is injected into the power gain stage.
摘要:
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 (10A, 12A) are provided, one of which is a part of a master oscillator (10) producing a very narrow band seed beam which is amplified in the second discharge chamber (12). The chambers (10A, 12A) can be controlled separately permitting separate optimization of wavelength parameters in the master oscillator (10) and optimization of pulse energy parameters in the amplifying chamber (12A). 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 (10A, 12A) comprises a single tangential fan (10A, 10) providing sufficient gas flow (11) to permit operation at pulse rates of 4,000 Hz or greater by clearing debris from the discharge region in less time than the approximately 0.25 milliseconds between pulses. The master oscillator (10) is equipped with a line narrowing package (16, 16A) having a very fast tuning mirror capable of controlling centerline wavelength on a pulse-to-pulse basis at repetition rates of 4,000 Hz or greater to a precision of less than 0.2 pm.
摘要:
A single chamber gas discharge laser system having a pulse power source for producing electrical discharges at the rate of at least 1000 pulses per second. The discharge, along with laser optics, create two short lived gain media, one for producing a seed beam and the other for amplifying the seed beam. Laser gas circulation around a chamber circulation path is provided and the electrodes (18A) and discharges are arranged so that debris from one of the gain medium is not circulated to the other gain medium during discharges until the debris has made a loop around at least 90 % of the chamber circulation path.
摘要:
A turnable injection seeded very narrow band F2 lithography laser. The laser (60) combines modular design features of prior art long life reliable lithography lasers with special techniques to produce a seed beam (LNP15) operated in a first gain medium which beam (102) is used to stimulate narrow bnd lasing in a second gain medium to produce a very narrow band laser useful for integrated circuit lithography. In a preferred embodiment, two tunable etalon output couplers (164A, 164B) are used to narrow band an F2 laser and the output of the seed laser is amplified in an F2 amplifier.
摘要:
Die Laservorrichtung hat einen Laseroszillator (10) und einen nachgeschalteten Laserverstärker (13), der einen Eintrittsbereich für den zu verstärkenden, vom Laseroszillator (10) kommenden Laserstrahl (11) und einen Austritt für den verstärkten Laserstrahl (22) aufweist. Der Laserverstärker (13) hat außerdem einen Faltungsspiegel (14), der dem Eintrittsbereich für den zu verstärkenden Laserstrahl (11) gegenüberliegt. Der Eintrittsbereich für den zu verstärkenden Laserstrahl (11) ist eine Öffnung (18) in einem weiteren Faltungsspiegel (14) der dem anderen Faltungsspiegel (15) gegenüberliegt. Der Austritt für den verstärkten Laserstrahl (22) ist ebenfalls eine Öffnung in einem der beiden Faltungsspiegel. Die Öffnungsweite der Eintritts- und der Austrittsöffnung ist in bezug auf die Spiegelfläche des jeweiligen Faltungsspiegels (14, 15) klein. Der Querschnitt des Laserstahles innerhalb des Laserverstärkers (13) ist zumindest teilweise um ein Vielfaches größer als im Bereich der Eintritts- und der Austrittsöffnung.