Abstract: A pulsed gas discharge laser operating at an output laser pulse repetition rate of greater than 4 kHz and a method of operating same is disclosed which may comprise a high voltage electrode having a longitudinal extent; a main insulator electrically insulating the high voltage electrode from a grounded gas discharge chamber; a preionizer longitudinally extending along at least a portion of the longitudinal extent of the high voltage electrode; a preionization shim integral with the electrode extending toward the preionizer. The preionizer may be formed integrally with the main insulator. The preionization shim may substantially cover the gap between the electrode and the preionizer. The apparatus and method may comprise an aerodynamic fairing attached to the high voltage electrode to present an aerodynamically smooth surface to the gas flow.

Abstract: A system and method of operating a high repetition rate gas discharge laser system. The system includes a gas discharge chamber having a hot chamber output window heated by the operation of the gas discharge laser chamber, an output laser light pulse beam path enclosure downstream of the hot chamber window and comprising an ambient temperature window, a cooling mechanism cooling the beam path enclosure intermediate the output window and the ambient window. The gas discharge chamber can include a longitudinally and axially compliant ground rod, including a first end connected to a first chamber wall, a second end connected to a second chamber wall, the second chamber wall opposite the first chamber wall and a first portion formed into a helical spring, the ground rod providing mechanical support for a preionizer tube.

Abstract: A cross-flow fan impeller for circulating gas in a transversely excited, pulsed, gas discharge laser is disclosed and may comprise a plurality of hubs, the hubs spaced apart along the impeller's rotation axis and establishing at least two impeller segments wherein a first segment has an output flow within 80-120% of a second segment and the first and second segment having differing blade pass frequencies. In some embodiments of this aspect, the first segment may have n number of blades the second segment m number of blades, and m?n. In one embodiment, the impeller may be configured with n=29 and m=23 and in another embodiment, the impeller may be configured with n=23 and m=19. The impeller may be configured wherein n and m are prime numbers.

Abstract: A system and method of operating a high repetition rate gas discharge laser system. The system includes a gas discharge chamber having a hot chamber output window heated by the operation of the gas discharge laser chamber, an output laser light pulse beam path enclosure downstream of the hot chamber window and comprising an ambient temperature window, a cooling mechanism cooling the beam path enclosure intermediate the output window and the ambient window. The gas discharge chamber can include a longitudinally and axially compliant ground rod, including a first end connected to a first chamber wall, a second end connected to a second chamber wall, the second chamber wall opposite the first chamber wall and a first portion formed into a helical spring, the ground rod providing mechanical support for a preionizer tube.

Abstract: A pulsed gas discharge laser operating at an output laser pulse repetition rate of greater than 4 kHz and a method of operating same is disclosed which may comprise a high voltage electrode having a longitudinal extent; a main insulator electrically insulating the high voltage electrode from a grounded gas discharge chamber; a preionizer longitudinally extending along at least a portion of the longitudinal extent of the high voltage electrode; a preionization shim integral with the electrode extending toward the preionizer. The preionizer may be formed integrally with the main insulator. The preionization shim may substantially cover the gap between the electrode and the preionizer. The apparatus and method may comprise an aerodynamic fairing attached to the high voltage electrode to present an aerodynamically smooth surface to the gas flow.

Abstract: A pulsed gas discharge laser operating at an output laser pulse repetition rate of greater than 4 kHz and a method of operating same is disclosed which may comprise a high voltage electrode having a longitudinal extent; a main insulator electrically insulating the high voltage electrode from a grounded gas discharge chamber; a preionizer longitudinally extending along at least a portion of the longitudinal extent of the high voltage electrode; a preionization shim integral with the electrode extending toward the preionizer. The preionizer may be formed integrally with the main insulator. The preionization shim may substantially cover the gap between the electrode and the preionizer.

Abstract: A corona-discharge type, preionizer assembly for a gas discharge laser is disclosed. The assembly may include an electrode and a hollow, dielectric tube that defines a tube bore. In one aspect, the electrode may include a first elongated 0o conductive member having a first end disposed in the bore of the tube. In addition, the electrode may include a second elongated conductive member having a first end disposed in the bore and spaced from the first end of the first conductive member. For the assembly, the first and second conductive members may be held at a same voltage potential.

Abstract: A fluorine gas discharge laser electrode for a gas discharge laser having a laser gas containing fluorine is disclosed which may comprise a copper and copper alloy cathode body having an upper curved region containing the discharge footprint for the cathode comprising copper and a lower portion comprising a copper alloy, with the facing portion of the electrode if formed in a arcuate shape extending into straight line portions on either side of the arcuate portion, the straight line portions terminating in vertical straight sides, with the boundary between the copper including at least the arcuate portion, the electrode may comprise a bonded element machined from two pieces of material the first made of copper and the second made of a copper alloy bonded together before machining.

Abstract: A method and apparatus if disclosed which may comprise a high power high repetition rate gas discharge laser UV light source which may comprise: a gas discharge chamber comprising an interior wall comprising a vertical wall and an adjacent bottom wall; a gas circulation fan creating a gas flow path adjacent the interior vertical wall and the adjacent bottom wall; an in-chamber dust trap positioned a region of low gas flow, which may be along an interior wall and may comprise at least one meshed screen, e.g., a plurality of meshed screens, which may comprise at least two different gauge meshed screens. The dust trap may extend along the bottom interior wall of the chamber and/or a vertical portion of the interior wall. The dust trap may comprise a first meshed screen having a first gauge; a second meshed screen having a second gauge smaller than the first gauge; and the second meshed screen intermediate the first meshed screen and the interior wall.

Abstract: A cross-flow fan impeller for circulating gas in a transversely excited, pulsed, gas discharge laser is disclosed and may comprise a plurality of hubs, the hubs spaced apart along the impeller's rotation axis and establishing at least two impeller segments wherein a first segment has an output flow within 80-120% of a second segment and the first and second segment having differing blade pass frequencies. In some embodiments of this aspect, the first segment may have n number of blades the second segment m number of blades, and m?n. In one embodiment, the impeller may be configured with n=29 and m=23 and in another embodiment, the impeller may be configured with n=23 and m=19. The impeller may be configured wherein n and m are prime numbers.

Abstract: An EUV light source apparatus and method are disclosed, which may comprise a pulsed laser providing laser pulses at a selected pulse repetition rate focused at a desired target ignition site; a target formation system providing discrete targets at a selected interval coordinated with the laser pulse repetition rate; a target steering system intermediate the target formation system and the desired target ignition site; and a target tracking system providing information about the movement of target between the target formation system and the target steering system, enabling the target steering system to direct the target to the desired target ignition site.

Abstract: A chamber for a gas discharge laser is disclosed and may include a chamber housing having a wall, the wall having an inside surface surrounding a chamber volume and an outside surface, the wall also being formed with an orifice. For the chamber, at least one electrical conductor may extend through the orifice to pass an electric current into the chamber volume. A member may be disposed between the conductor and the wall for preventing gas flow through the orifice to allow a chamber pressure to be maintained in the volume. The chamber may further comprise a pressurized compartment disposed adjacent to the orifice for maintaining a pressure on at least a portion of the outside surface of the wall to reduce bowing of the wall near the orifice due to chamber pressure.

Abstract: A chamber for a gas discharge laser is disclosed and may include a chamber housing having a wall, the wall having an inside surface surrounding a chamber volume and an outside surface, the wall also being formed with an orifice. For the chamber, at least one electrical conductor may extend through the orifice to pass an electric current into the chamber volume. A member may be disposed between the conductor and the wall for preventing gas flow through the orifice to allow a chamber pressure to be maintained in the volume. The chamber may further comprise a pressurized compartment disposed adjacent to the orifice for maintaining a pressure on at least a portion of the outside surface of the wall to reduce bowing of the wall near the orifice due to chamber pressure.

Abstract: A gas discharge laser includes a laser chamber containing a halogen laser gas, two electrode elements defining a cathode and an anode, each having a discharge receiving region defining two longitudinal edges and having a region width defining a width of an electric discharge between the electrode elements in the laser gas. The anode comprising a first anode portion comprising a first anode material defining a first anode material erosion rate, located entirely within the discharge receiving region, a pair of second anode portions comprising a second anode material defining a second anode material erosion rate, respectively located on each side of the first anode portion and at least partially within the discharge receiving region; an electrode center base portion integral with the first anode portion; and wherein each of the respective pair of second anode portions is mechanically bonded to the center base portion.

Abstract: Electrodes for a fluorine gas discharge laser are disclosed which may comprise a crown straddling the centerline axis between the pair of side walls and the pair of end walls, comprising a first material, forming at least a portion of the discharge region of the electrode; the crown in traverse cross section having the shape of the upper half of a canted ellipse rotated in the preionizer direction, such that a tangent to the short centerline axis of the ellipse forms an angle with the horizontal. Another embodiment may comprise an anode blade having a top portion and a first and second sidewall portion each intersecting the top portion; the anode blade being formed with the shape in cross section of the top portion being curvilinear and intersecting the generally straight potions of each of first and second sidewall portions along a radius of curvature and with the top portion beveled away from an asymmetric discharge side of the anode.

Abstract: The present invention provides a gas discharge laser having at least one long-life elongated electrode for producing at least 12 billion high voltage electric discharges in a fluorine containing laser gas. In a preferred embodiment at least one of the electrodes is comprised of a first material having a relatively low anode erosion rate and a second anode material having a relatively higher anode erosion rate. The first anode material is positioned at a desired anode discharge region of the electrode. The second anode material is located adjacent to the first anode material along at least two long sides of the first material. During operation of the laser erosion occurs on both materials but the higher erosion rate of the second material assures that any tendency of the discharge to spread onto the second material will quickly erode away the second material enough to stop the spread of the discharge.

Abstract: A method and apparatus for producing a very high repetition rate gas discharge laser system in a MOPA configuration is disclosed which may comprise a master oscillator gas discharge layer system producing a beam of oscillator laser output light pulses at a very high pulse repetition rate; at least two power amplification gas discharge laser systems receiving laser output light pulses from the master oscillator gas discharge laser system and each of the at least two power amplification gas discharge laser systems amplifying some of the received laser output light pulses at a pulse repetition that is a fraction of the very high pulse repetition rate equal to one over the number of the at least two power amplification gas discharge laser systems to form an amplified output laser light pulse beam at the very high pulse repetition rate, which may be positioned in series with respect to the oscillator laser output light pulse beam.

Abstract: The present invention provides a gas discharge laser having at least one long-life elongated electrode for producing at least 12 billion high voltage electric discharges in a fluorine containing laser gas. In a preferred embodiment at least one of the electrodes is comprised of a first material having a relatively low anode erosion rate and a second anode material having a relatively higher anode erosion rate. The first anode material is positioned at a desired anode discharge region of the electrode. The second anode material is located adjacent to the first anode material along at least two long sides of the first material. During operation of the laser erosion occurs on both materials but the higher erosion rate of the second material assures that any tendency of the discharge to spread onto the second material will quickly erode away the second material enough to stop the spread of the discharge.

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: Electrodes for a fluorine gas discharge laser are disclosed which may comprise a crown straddling the centerline axis between the pair of side walls and the pair of end walls, comprising a first material, forming at least a portion of the discharge region of the electrode; the crown in traverse cross section having the shape of the upper half of a canted ellipse rotated in the preionizer direction, such that a tangent to the short centerline axis of the ellipse forms an angle with the horizontal. Another embodiment may comprise an anode blade having a top portion and a first and second sidewall portion each intersecting the top portion; the anode blade being formed with the shape in cross section of the top portion being curvilinear and intersecting the generally straight potions of each of first and second sidewall portions along a radius of curvature and with the top portion beveled away from an asymmetric discharge side of the anode.