High pulse repetition rate gas discharge laser

Patent metadata

Field	Value
Publication number	US-9620920-B2
Application number	US-59030709-A
Country	US
Kind code	B2
Filing date	Nov 5, 2009
Priority date	Jun 27, 2005
Publication date	Apr 11, 2017
Grant date	Apr 11, 2017

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.

First claim

We claim:

1. A pulsed gas discharge laser operating at an output laser output light pulse repetition rate of greater than 4 kHz comprising:
a cathode having a first elongated discharge receiving area;
an anode support bar having a dugout region, the dugout region having a substantially flat bottom surface;
an anode disposed in the dugout region of the anode support bar, the anode having:
a second elongated discharge receiving area facing the first elongated discharge receiving area of the cathode, a discharge region defined between the first elongated discharge receiving area and the second elongated discharge receiving area;
a substantially flat anode bottom surface disposed on the substantially flat bottom surface of the dugout region;
an upstream side surface;
a downstream side surface, the second elongated discharge receiving area having a first width between upstream side surface and the downstream side surface, the upstream side surface having a first linear slope forming a first obtuse angle to the substantially flat bottom surface of the dugout region, the downstream side surface having a second linear slope forming a second obtuse angle to the substantially flat bottom surface of the dugout region, the first obtuse angle being opposite from the second obtuse angle the flat anode bottom surface having a second width greater than the first width between upstream side surface and the downstream side surface;

a preionizer adjacent to the cathode, the preionizer and the cathode being disposed in an electrode pocket, the electrode pocket and the cathode, forming a gas flow disturbance pocket;
a first aerodynamic cathode fairing attached to the cathode and substantially closing the gas flow disturbance pocket and having an aerodynamically smooth surface to the gas flow in a downstream flow path defined as flowing from a blower and through the discharge region, and the first aerodynamic cathode fairing is disposed on a first side of the first elongated discharge receiving area and the preionizer being disposed on a second side of the first elongated discharge receiving area, the second side of the first elongated discharge receiving area being opposite from the first side of the first elongated discharge receiving area.

2. The apparatus of claim 1 , wherein the upstream side surface of the anode is separated from the upstream sidewall of the dugout region by an upstream gap and the downstream side surface is separated from the downstream sidewall of the dugout region by a downstream gap.

3. The apparatus of claim 1 , further comprising an upstream anode fairing disposed between the upstream side surface and the upstream sidewall of the dugout region and a downstream anode fairing disposed between the downstream side surface and the downstream sidewall of the dugout region.

4. The apparatus of claim 3 , wherein a portion of an upper surface of the anode support bar, an upper surface of upstream anode fairing and an upper surface of the downstream anode fairing are aligned to form a single anode aerodynamically smooth surface to the gas flow from the blower and through the discharge region.

5. The apparatus of claim 1 , wherein the electrode pocket is formed in a main insulator, the electrode pocket including:
a first outer extent side wall;
a second outer extent side wall;
the cathode including:
a first side surface adjacent to and extending from the first elongated discharge receiving area of the cathode toward the first outer extent side wall along a third linear slope the first side surface forms a first acute angle relative to the first outer extent side wall, defining a first gap;
a second side surface adjacent to and extending from the first elongated discharge receiving area of the cathode toward the second outer extent side wall along a fourth linear slope the second side surface disposed opposite from the first side surface, the second side surface forms a second acute angle relative to the second outer extent side wall, defining a second gap;
a second aerodynamic cathode fairing being attached to the first side surface of the cathode and substantially closing the first gap and presenting an aerodynamically smooth surface to the gas flow.

6. The apparatus of claim 5 , wherein the cathode is formed with an integral shim extending toward the preionizer and the integral shim forming a second aerodynamically smooth surface to the gas flow.

7. The apparatus of claim 5 , wherein the first aerodynamic cathode fairing includes:
a wedge cross-sectional shape; and
two integral mounting pads disposed outboard of the cathode in an longitudinal extent of the cathode, the two integral mounting pads being affixed to the main insulator.

Assignees

• Gillespie Walter D
• Steiger Thomas D
• Ujazdowski Richard C
• Partlo William N
• Cymer LLC

Inventors

• Gillespie Walter D
• Steiger Thomas D
• Ujazdowski Richard C
• Partlo William N

Classifications

• H01S3/036 Primary

  Means for obtaining or maintaining the desired gas pressure within the tube, e.g. by gettering, replenishing; Means for circulating the gas, e.g. for equalising the pressure within the tube {(H01S3/031 takes precedence)} · CPC title

• H01S3/0384

  Auxiliary electrodes, e.g. for pre-ionisation or triggering, or particular adaptations therefor · CPC title