Gas optimization in a gas discharge light source

Patent metadata

Field	Value
Publication number	US-10892594-B2
Application number	US-201816232321-A
Country	US
Kind code	B2
Filing date	Dec 26, 2018
Priority date	Feb 16, 2016
Publication date	Jan 12, 2021
Grant date	Jan 12, 2021

Abstract

In a method, energy is supplied to a first gas discharge chamber of a first stage until a pulsed amplified light beam is output from the first stage and directed toward a second stage. While the energy is supplied to the first gas discharge chamber: a value of an operating parameter of the first gas discharge chamber is measured; it is determined whether to adjust an operating characteristic of the first gas discharge chamber based on the measured value; and, the operating characteristic of the first gas discharge chamber is adjusted if it is determined that the operating characteristic of the first gas discharge chamber should be adjusted. After it is determined that the operating characteristic of the first gas discharge chamber no longer should be adjusted, then an adjustment procedure is applied to an operating characteristic of a second gas discharge chamber of the second stage.

First claim

What is claimed is:

1. A method comprising:
performing a first full replenishment of a first gas mixture in a first gas discharge chamber of a first stage of a light source, the first full replenishment comprising replacing the first gas mixture in the first gas discharge chamber;
performing a second full replenishment of a second gas mixture in a second gas discharge chamber of a second stage of the light source, the second full replenishment comprising replacing the second gas mixture in the second gas discharge chamber;
after the first and second full replenishments are completed, performing a first gas adjustment procedure on the first gas discharge chamber, the first gas adjustment procedure comprising adjusting one or more operating characteristics of the first gas discharge chamber based on one or more operating parameters of the first gas discharge chamber;
determining that the one or more operating characteristics of the first gas discharge chamber no longer should be adjusted;
after the first gas adjustment procedure is completed and after it has been determined that the one or more operating characteristics of the first gas discharge chamber no longer should be adjusted, feeding a pulsed amplified light beam output from the first stage to the second stage and performing a second gas adjustment procedure on the second gas discharge chamber, the second gas adjustment procedure on the second gas discharge chamber comprising adjusting one or more operating characteristics of the second gas discharge chamber based on one or more operating parameters of the second gas discharge chamber; and
after completion of the first and second gas adjustment procedures, operating the light source under normal operating conditions.

2. The method of claim 1 , wherein adjusting the one or more operating characteristics of the first gas discharge chamber based on the one or more operating parameters of the first gas discharge chamber comprises supplying energy to the first gas discharge chamber using a first pulsed energy source until a pulsed amplified light beam is output from the first stage.

3. The method of claim 1 , wherein adjusting one or more operating characteristics of the first gas discharge chamber comprises adjusting a condition of the first gas mixture in the first gas discharge chamber and adjusting one or more operating characteristics of the second gas discharge chamber comprises adjusting a condition of the second gas mixture in the second gas discharge chamber.

4. The method of claim 1 , wherein:
the one or more operating parameters of the first gas discharge chamber include an energy of a pulsed amplified light beam output from the first gas discharge chamber and/or a spectral property of the pulsed amplified light beam output from the first gas discharge chamber; and
the one or more operating parameters of the second gas discharge chamber include an energy of a pulsed amplified light beam output from the second gas discharge chamber and/or a spectral property of the pulsed amplified light beam output from the second gas discharge chamber.

5. The method of claim 1 , wherein:
the one or more operating characteristics of the first gas discharge chamber include a pressure of the first gas mixture in the first gas discharge chamber and/or an optical feature of a pulsed amplified light beam output from the first gas discharge chamber; and
the one or more operating characteristics of the second gas discharge chamber include a pressure of the second gas mixture in the second gas discharge chamber and/or an optical feature of a pulsed amplified light beam output from the second gas discharge chamber.

6. The method of claim 1 , wherein the second gas adjustment procedure is decoupled from the first gas adjustment procedure.

7. The method of claim 1 , wherein performing the second gas adjustment procedure on the second gas discharge chamber comprises performing a margin-based gas adjustment procedure on the second gas discharge chamber.

8. The method of claim 7 , wherein performing the margin-based gas adjustment procedure on the second gas discharge chamber comprises operating the light source under a set of extreme test conditions while observing the one or more operating parameters of the second gas discharge chamber.

9. The method of claim 7 , wherein performing the margin-based gas adjustment procedure on the second gas discharge chamber comprises measuring extreme values of one or more operating parameters of the light source.

10. The method of claim 7 , wherein performing the margin-based gas adjustment procedure on the second gas discharge chamber comprises:
estimating one or more extreme values of operating parameters associated with the second gas discharge chamber while operating the light source under a set of extreme test conditions, the estimating comprising, for each extreme test condition:
operating the light source under the extreme test condition; and
measuring an extreme value of an operating parameter for the extreme test condition;

determining whether to adjust at least one operating characteristic of the second gas discharge chamber based on the estimated one or more extreme values of the operating parameters; and
if it is determined that an operating characteristic of the second gas discharge chamber should be adjusted, then adjusting that operating characteristic of the second gas discharge chamber.

11. The method of claim 10 , wherein determining whether to adjust at least one operating characteristic of the second gas discharge chamber comprises determining whether to adjust one or more of: a condition of the second gas mixture; and an optical feature of a pulsed amplified light beam output from the second stage.

12. The method of claim 7 , wherein performing the margin-based gas adjustment procedure on the second gas discharge chamber comprises:
determining whether to adjust at least one operating characteristic of the second gas discharge chamber; and
if it is determined that an operating characteristic of the second gas discharge chamber should be adjusted, then adjusting that operating characteristic;
wherein determining whether to adjust at least one operating characteristic of the second gas discharge chamber is based on one or more estimated extreme values of operating parameters associated with the second gas discharge chamber while operating the light source under a set of extreme test conditions.

13. The method of claim 1 , wherein adjusting the one or more operating characteristics of the first gas discharge chamber occurs while a timing between the pulses of the amplified light beam output from the first gas discharge chamber and pulses of an amplified light beam output from the second gas discharge chamber is detuned and/or held constant.

14. The method of claim 1 , wherein adjusting the one or more operating characteristics of the first gas discharge chamber comprises adjusting the one or more operating characteristic of the first gas discharge chamber while an energy that is supplied to the first gas discharge chamber is held constant.

15. The method of claim 14 , wherein adjusting the one or more operating characteristics of the first gas discharge chamber while the energy that is supplied to the first gas discharge chamber is held constant comprises adjusting the one or more operating characteristics of the first gas discharge chamber while the energy that is supplied to the first gas discharge chamber is held at a maximum acceptable voltage.

16. The method of claim 1 , wherein adjusting one or more operating characteristics of the first gas d

Assignees

• Cymer LLC

Inventors

• Aggarwal Tanuj

Classifications

• H01S3/2308

  Amplifier arrangements, e.g. MOPA · CPC title

• H01S3/225

  comprising an excimer or exciplex · CPC title

• H01S3/134 Primary

  in gas lasers · CPC title

• H01S3/1305

  Feedback control systems · CPC title

• H01S3/104

  in gas lasers · CPC title