Patents by Inventor Igor Bragin
Igor Bragin has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 7079565Abstract: Arcing can be minimized in a discharge chamber of an excimer or molecular fluorine laser system by utilizing an improved electrode structure. An electrode structure can include at least one ceramic spoiler positioned near the discharge region of the electrode. An insulating ceramic spoiler can reduce the effective area over which arcing can occur, and can reduce the likelihood of arcing by improving the flow of gas between the electrodes, such as by allowing for design flexibility and reducing the necessary height of a nose portion used to control the discharge area of the electrode. An improved blower design, which can utilize improved bearings and a dry film lubricant, can help to circulate the laser gas between the electrode structures, such as at a speed of at least 30 m/s in order to operate the laser at repetition rates of 4 kHz or higher.Type: GrantFiled: December 4, 2003Date of Patent: July 18, 2006Assignee: Lambda Physik AGInventors: Igor Bragin, Vadim Berger, Oleg Melnikov, Konstantin Aab, Juergen Baumler
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Publication number: 20060056478Abstract: 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.Type: ApplicationFiled: October 31, 2005Publication date: March 16, 2006Inventors: Hans-Stephen Albrecht, Klaus Vogler, Juergen Kleinschmidt, Thomas Schroeder, Igor Bragin, Vadim Berger, Uwe Stamm, Wolfgang Zschocke, Sergei Govorkov
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Patent number: 6987790Abstract: Precise timing control can be obtained for a gas discharge laser, such as an excimer or molecular fluorine laser, using a timed trigger ionization. Instead of using a standard approach to control the timing of the emission or amplification of an optical pulse using the discharge of the main electrodes, the timing of which can only be controlled to within about 10 ns, a trigger ionization pulse applied subsequent to the charging of the main electrodes can be used to control the timing of the discharge, thereby decreasing the timing variations to about 1 ns. Since ionization of the laser gas can consume relatively small amounts of energy, such a circuit can be based on a fast, high-voltage, solid state switch that is virtually free of jitter. Trigger ionization also can be used to synchronize the timing of dual chambers in a MOPA configuration. In one such approach, ionization trigger can include at least a portion of the optical pulse from the oscillator in a MOPA configuration.Type: GrantFiled: February 11, 2004Date of Patent: January 17, 2006Assignee: Lambda Physik AGInventors: Sergei V. Govorkov, Rainer Paetzel, Igor Bragin, Rainer Desor, Andreas Targsdorf, Andriy Knysh
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Patent number: 6965624Abstract: 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.Type: GrantFiled: January 6, 2003Date of Patent: November 15, 2005Assignee: Lambda Physik AGInventors: Hans-Stephan Albrecht, Klaus Wolfgang Vogler, Juergen Kleinschmidt, Thomas Schroeder, Igor Bragin, Vadim Berger, Uwe Stamm, Wolfgang Zschocke, Sergei Govorkov
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Publication number: 20050083984Abstract: The lifetime of the laser gas in a laser system such as an excimer laser can be increased by changing the way in which the laser system is sealed. In addition to primary seals used to seal the reservoir chamber and discharge channel, at least one secondary seal can be used between the primary seals and the surrounding environment in order to further prevent permeation of impurities into the discharge chamber, as well as to create an intermediate gas volume. A controlled atmosphere can be generated in the intermediate gas volume, which can be at a slightly higher pressure than the surrounding environment in order to resist the flow of impurities through the secondary seal(s). Further, a flow of purge gas can be introduced into the controlled atmosphere in order to carry away any impurities that leak through the secondary seal(s).Type: ApplicationFiled: October 12, 2004Publication date: April 21, 2005Inventors: Igor Bragin, Rainer Paetzel, Juergen Baumler, Heiko Diesing, Helmer Beulshausen, Ulrich Rebhan
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Publication number: 20050058172Abstract: The stability of a gas discharge in an excimer or molecular fluorine laser system can be improved by generating multiple discharge pulses in the resonator chamber, instead of a single discharge pulse. Each of these discharges can be optimized in both energy transfer and efficient coupling to the gas. The timing of each discharge can be controlled using, for example, a common pulser component along with appropriate circuitry to provide energy pulses to each of a plurality of segmented main discharge electrodes. Applying the energy to the segmented electrodes rather than to a standard discharge electrode pair allows for an optimization of the temporal shape of the resulting superimposed laser pulse. The optimized shape and higher stability can allow the laser system to operate at higher repetition rates, while minimizing the damage to system and/or downstream optics.Type: ApplicationFiled: September 8, 2004Publication date: March 17, 2005Inventors: Rainer Paetzel, Igor Bragin, Andreas Targsdorf, Vadim Berger, Rustem Osmanow
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Publication number: 20050031004Abstract: A Master Oscillator (MO)—Power Amplifier (PA) configuration (MOPA) can be used advantageously in an excimer laser system for micro-lithography applications, where semiconductor manufacturers demand powers of 40 W or more in order to support the throughput requirements of advanced lithography scanner systems. The timing of discharges in discharge chambers of the MO and PA can be precisely controlled using a common pulser to drive the respective chambers. The timing of the discharges further can be controlled through the timing of the pre-ionization in the chambers, or through control of the reset current in the final compression stages of the pulser. A common pulser, or separate pulser circuits, also can be actively controlled in time using a feedback loop, with precision timing being achieved through control of the pre-ionization in each individual discharge chamber. Yet another system provides for real-time compensation of time delay jitter of discharge pulses in the chambers.Type: ApplicationFiled: November 3, 2003Publication date: February 10, 2005Inventors: Dirk Basting, Sergei Govorkov, Rainer Paetzel, Igor Bragin, Andreas Targsdorf
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Publication number: 20050002427Abstract: The consumption and/or erosion of electrodes in high repetition rate gas discharge lasers, such as excimer or molecular fluorine lasers, can be reduced using any of a number of temperature regulation approaches described herein. A flow of a cooling medium can be used to remove heat from the electrodes during laser operation, in order to reduce the rate of consumption and/or erosion. The rate of erosion can be controlled by adjusting the rate and/or temperature of the cooling medium flowing through the electrodes, or in bodies in good thermal contact with those electrodes. The cooled electrodes also can function to remove heat from the laser gas, and can have finned surfaces to facilitate such heat removal. Regulating the temperature of the electrodes and laser gas also can function to minimize resonance effects in the laser gas due to the presence of temperature gradients.Type: ApplicationFiled: April 28, 2004Publication date: January 6, 2005Inventors: Igor Bragin, Vadim Berger, Ulrich Rebhan, Norbert Niemoller, Konstantin Aab
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Patent number: 6834066Abstract: Method and system for providing stabilization techniques for high repetition rate gas discharge lasers with active loads provided in the discharge circuitry design which may include a resistance provided in the discharge circuitry.Type: GrantFiled: April 18, 2001Date of Patent: December 21, 2004Assignee: Lambda Physik AGInventors: Igor Bragin, Vadim Berger, Juergen Kleinschmidt
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Publication number: 20040252740Abstract: 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.Type: ApplicationFiled: January 6, 2003Publication date: December 16, 2004Applicant: Lambda Physik AG.Inventors: Hans-Stephan Albrecht, Klaus Wolfgang Vogler, Juergen Kleinschmidt, Thomas Schroeder, Igor Bragin, Vadim Berger, Uwe Stamm, Wolfgang Zschocke, Sergei Govorkov
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Publication number: 20040202219Abstract: Precise timing control can be obtained for a gas discharge laser, such as an excimer or molecular fluorine laser, using a timed trigger ionization. Instead of using a standard approach to control the timing of the emission or amplification of an optical pulse using the discharge of the main electrodes, the timing of which can only be controlled to within about 10 ns, a trigger ionization pulse applied subsequent to the charging of the main electrodes can be used to control the timing of the discharge, thereby decreasing the timing variations to about 1 ns. Since ionization of the laser gas can consume relatively small amounts of energy, such a circuit can be based on a fast, high-voltage, solid state switch that is virtually free of jitter. Trigger ionization also can be used to synchronize the timing of dual chambers in a MOPA configuration. In one such approach, ionization trigger can include at least a portion of the optical pulse from the oscillator in a MOPA configuration.Type: ApplicationFiled: February 11, 2004Publication date: October 14, 2004Inventors: Sergei V. Govorkov, Rainer Paetzel, Igor Bragin, Rainer Desor, Andreas Targsdorf, Andriy Knysh
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Publication number: 20040179571Abstract: Pulse parameters of a gas discharge laser system can be optimized and controlled for precision applications such as microlithography. Important laser pulse parameters typically vary in the beginning of a pulse burst, and the directionality of the output beam typically varies throughout the burst. In order to improve the performance of the laser system, the variation at the beginning of a pulse burst can be eliminated by extending the pulse pattern and shuttering the output during periods of significant parameter variation. A fast shutter such as an acousto-optical modulator can be used to prevent output during the burst transition processes. Elements such as acousto-optical cells also can be used in combination with a fast position sensor to steer the direction of the output beam, in order to adjust for variations in the direction of the beam between pulses in a burst.Type: ApplicationFiled: February 11, 2004Publication date: September 16, 2004Inventors: Sergei V. Govorkov, Alexander O. Wiessner, Rainer Paetzel, Igor Bragin
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Patent number: 6785316Abstract: A final stage capacitance of a pulse compression circuit for an excimer or molecular fluorine lithography laser system is provided by a set of peaking capacitors connected through a first inductance to the electrodes and a set of sustaining capacitors connected to the electrodes through a second inductance substantially greater than the first inductance. Current pulses through the discharge are temporally extended relative to current pulses of a system having its final stage capacitance provided only by a set of peaking capacitors connected to the electrodes via the first inductance. An amplified spontaneous emission (ASE) level in the laser pulses is reduced thereby enhancing their spectral purity.Type: GrantFiled: August 17, 2000Date of Patent: August 31, 2004Assignee: Lambda Physik AGInventors: Igor Bragin, Vadim Berger, Uwe Stamm
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Publication number: 20040131100Abstract: Arcing can be minimized in a discharge chamber of an excimer or molecular fluorine laser system by utilizing an improved electrode structure. An electrode structure can include at least one ceramic spoiler positioned near the discharge region of the electrode. An insulating ceramic spoiler can reduce the effective area over which arcing can occur, and can reduce the likelihood of arcing by improving the flow of gas between the electrodes, such as by allowing for design flexibility and reducing the necessary height of a nose portion used to control the discharge area of the electrode. An improved blower design, which can utilize improved bearings and a dry film lubricant, can help to circulate the laser gas between the electrode structures, such as at a speed of at least 30 m/s in order to operate the laser at repetition rates of 4 kHz or higher.Type: ApplicationFiled: December 4, 2003Publication date: July 8, 2004Inventors: Igor Bragin, Vadim Berger, Oleg Melnikov, Konstantin Aab, Juergen Baumler
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Patent number: 6757315Abstract: A preionization device for a gas laser includes an internal preionization electrode having a dielectric housing around it such that the preionization device is of corona type. The internal electrode connects to advantageous electrical circuitry, preferably external to the discharge chamber via a conductive feedthrough. The circuitry reduces the voltage across the dielectric tube of the preionization unit to reduce over-flashing at tube ends and oscillations due to residual energies stored in the dielectric. A semi-transparent mesh electrode between the preionization unit and the discharge area prevents field distortions and discharge instabilities.Type: GrantFiled: October 19, 2000Date of Patent: June 29, 2004Assignee: Lambda Physik AGInventors: Igor Bragin, Vadim Berger, Ivan Tassy-Julien, Uwe Stamm
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Patent number: 6721345Abstract: 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.Type: GrantFiled: July 12, 2001Date of Patent: April 13, 2004Assignee: Lambda Physik AGInventors: Igor Bragin, Juergen Kleinschmidt, Gerhard Ahlborn
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Patent number: 6714577Abstract: 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.Type: GrantFiled: February 25, 2000Date of Patent: March 30, 2004Assignee: Lambda Physik AGInventors: Uwe Stamm, Igor Bragin, Wolfgang Zschocke
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Patent number: 6650679Abstract: A preionization device for a gas laser comprises an internal preionization electrode having a dielectric housing around it and an external preionization electrode displaced from the dielectric housing by a small gap. The dielectric housing includes two cylindrical regions of differing outer radii of curvature. An open end of the housing has a larger radius of curvature than the other end which is closed. The internal electrode connects to circuitry external to the discharge chamber via a conductive feedthrough which penetrates through the housing. The external circuitry prevents voltage oscillations caused by residual energy stored as capacitance in the dielectric housing. The external preionization electrode, which is connected electrically to one of the main discharge electrodes, is formed to shield the internal preionization electrode from the other main discharge electrode to prevent arcing therebetween.Type: GrantFiled: February 10, 1999Date of Patent: November 18, 2003Assignee: Lambda Physik AGInventors: Igor Bragin, Ulrich Rebhan, Uwe Stamm, Dirk Basting
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Patent number: 6618422Abstract: A preionization device for a gas laser comprises an internal preionization electrode having a dielectric housing around it and an external preionization electrode displaced from the dielectric housing by a small gap. The dielectric housing includes two cylindrical regions of differing outer radii of curvature. An open end of the housing has a larger radius of curvature than the other end which is closed. The internal electrode connects to circuitry external to the discharge chamber via a conductive feedthrough which penetrates through the housing. The external circuitry prevents voltage oscillations caused by residual energy stored as capacitance in the dielectric housing. The external preionization electrode, which is connected electrically to one of the main discharge electrodes, is formed to shield the internal preionization electrode from the other main discharge electrode to prevent arcing therebetween.Type: GrantFiled: May 22, 2001Date of Patent: September 9, 2003Assignee: Lambda Physik AGInventors: Igor Bragin, Ulrich Rebhan, Uwe Stamm, Dirk Basting
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Patent number: 6570901Abstract: 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.Type: GrantFiled: February 22, 2001Date of Patent: May 27, 2003Assignee: Lambda Physik AGInventors: Uwe Stamm, Juergen Kleinschmidt, Igor Bragin