Lambda Physik Ag

Lambda Physik Gesellschaft Zur Herstellung Von Lasern Mbh

Lambda Physik Forschungs-und Entwicklungs-gesellschaft Mbh

Ulrich Rebhan

Uwe Stamm

Igor Bragin

Vadim Berger

Dirk Basting

Frank Voss

Guido Schriever

Rustem Osmanow

Gerd Steinfuhrer

Jurgen Baumler

Guenter Nowinski

Markus Ritcher

Kay Zimmerman

The method and system herein pertain to an EUV photon source which includes a plasma chamber filled with a gas mixture, multiple electrodes within the plasma chamber defining a plasma region and a central axis, a power supply circuit connected to the electrodes for delivering a main pulse to the electrodes for energizing the plasma around the central axis to produce an EUV beam. The system can also include a preionizer for ionizing the gas mixture in preparing to form a dense plasma around the central axis upon application of the main pulse from the power supply circuit to the electrodes. A set of baffles may be disposed along the beam path outside of the pinch region to diffuse gaseous and contaminant particulate flow emanating from the pinch region and to absorb or reflect acoustic waves emanating from the pinch region away from the pinch region.

Method and apparatus for generating high output power gas discharge based source of extreme ultraviolet radiation and/or soft x-rays

In an excimer laser or a molecular fluorine laser, a heating element is used which is heated to temperatures in excess of 60&deg; C., in order to remove impurities from the laser gas.

Gas discharge laser with means for removing gas impurities

A method and gas replenishment algorithm for excimer and molecular fluorine lasers is based on parameters upon which gas aging more closely depends than pulse count, such as input energy to the electrical discharge, and also preferably time. A burst control method and algorithm includes measuring the energies of initial pulses of a first burst occurring after a long burst break, calculating values of input voltages for the initial pulses that would bring output energies of the individual laser pulses or groups of pulses to substantially the same values, and applying the calculated voltages in a subsequent first burst after a long burst break to achieve substantially same predetermined output energy values for the pulses or groups of pulses. Similar operations may be performed for one or more subsequent bursts following the first burst. The values for the first burst may be maintained in a first table of input voltage values to be read by a processor which signals a power supply circuit to apply the voltages according to the voltage values in the table. The values for subsequent bursts may be maintained in a second table, and a third table, etc. A final table such as the third table may be used for all subsequent bursts until another long burst break again occurs, after which the first table is again used for the first burst following the long burst break.

Energy control for an excimer or molecular fluorine laser

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. The external electrode is also formed to shield the outer gas volume and walls of the discharge chamber from the preionization unit. A semi-transparent external electrode prevents charged particles emanating from the main discharge area from settling on the housing and causing field distortion and discharge instabilities.

Preionization arrangement for gas laser

Preionization arrangement for a gas laser

A method for testing a material block prior to forming the material block into one or more optical components for use with a sub-micron lithographic, high power, narrow bandwidth laser system having high wavelength stability includes the step of selecting a block of material having appropriate characteristic optical properties for the source laser system being used. The next step is to test the material block for absorption performance. Then, if the block exhibits a sufficient absorption performance, then one of more optical components such as one or more prisms, etalons, and/or windows, etc. are formed from the material block. Finally, the optical components formed from the block are inserted into a wavelength selection module of the resonator of the laser to participate in producing a high power, narrow bandwidth laser beam which may be used in sub-micron photolithographic applications.

Optical materials testing method

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. The curvatures of both main electrodes may conform to the curvature of the gas flow through the discharge chamber to further improve aerodynamic performance. A plurality of low inductive conducting ribs are connected to the grounded main electrode and shaped to provide a more uniform flow of gases through openings defined between adjacent ribs.

Discharge unit for a high repetition rate excimer or molecular fluorine laser

A beam shutter apparatus designed to handle high powered UV radiation is disclosed. The shutter includes a high reflectivity mirror mounted on a plate which can be rotated between a first position where the beam is reflected and redirected to a tool such as a beam dump and a second position where the beam is free to pass out of the laser, where the beam is free to pass out of the laser The shutter includes a support base with an angled upper surface upon which the mirror plate rests when in the second position. The support base has a beam path channel designed so that a beam can pass through the support base and out of the shutter when the mirrored plate is in the first position. The mirrored plate is rotated by a linkage, which is driven by an electrically powered actuator on a rotational magnet. The support base is machined out of a monolithic piece of metal allowing very high precision without the need for cumbersome alignment procedures.

Beam shutter for excimer laser

A ventilation system for industrial laser systems is disclosed which can minimize the cooling air intake required during normal operation. Adequate ventilation is maintained even if the housing is opened. Various sensors monitor the condition of the cooling air and can increase the air intake if required for cooling or safety. Such a ventilation system is of particular advantage for excimer lasers in microlithography applications because the consumption of conditioned clean room air is controlled by the actual needs of the laser device.

Laser ventilation system

Laser comprising at least one anode (1) and one cathode (2) for preionization and main discharge, the anode (1) and the cathode (2) having different standard potentials. The laser is distinguished by high reliability and long life. After several hours of operation, practically no material erosion at all is found at the electrodes.

Laser having at least one anode and one cathode for preionization and/or

A method of controlling the total energy amount of a plurality of laser pulses in which the accumulation of the energy amounts of the individual pulses is measured with an energy measuring device and the laser pulses are interrupted when a dose desired value of the accumulated energy amounts is reached, provides that for increasing the accuracy of the energy dose achieved several laser pulses before reaching the dose desired value the energy amount of the individual laser pulses is reduced.

Method of controlling the total energy amount of a plurality of laser

In an apparatus for purifying laser gas, comprising a cooling circuit for cleaning of the laser gas, the cooling circuit is separable from the laser and operable by way of a shunt line, independently of the laser.

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Göttingen, Germany

Ulrich Rebhan