Gas monitoring system

Patent metadata

Field	Value
Publication number	US-11988966-B2
Application number	US-201915734359-A
Country	US
Kind code	B2
Filing date	May 16, 2019
Priority date	Jun 13, 2018
Publication date	May 21, 2024
Grant date	May 21, 2024

Abstract

A system includes an optical source configured to emit a pulsed light beam, the optical source comprising one or more chambers, each of the one or more chambers configured to hold a gaseous gain medium, the gaseous gain medium being associated with an assumed gas life; at least one detection module configured to: receive and analyze data related to the pulsed light beam, and produce a beam quality metric based on the data related to the pulsed light beam; and a monitoring module configured to: analyze the beam quality metric, determine a health status of the gaseous gain medium based on the analysis of the beam quality metric, and produce a status signal based on the determined health status, the status signal indicating whether to extend use of the gaseous gain medium beyond the assumed gas life or to end use of the gaseous gain medium.

First claim

What is claimed is:

1. A system comprising:
an optical source configured to emit a pulsed light beam, the optical source comprising one or more chambers, each of the one or more chambers configured to hold a gaseous gain medium, the gaseous gain medium being associated with an assumed gas life;
at least one detection module configured to:
receive and analyze data related to the pulsed light beam, and
produce a beam quality metric based on the data related to the pulsed light beam; and

a monitoring module configured to:
determine whether a health status of the gaseous gain medium is good based on a comparison between the beam quality metric and a threshold specific to the data that produced the beam quality metric, and

if it is determined that the health status is good, issue a command signal indicating to extend use of the gaseous gain medium beyond the assumed gas life.

2. The system of claim 1 , wherein the threshold specific to the data that produced the beam quality metric includes a pre-determined specification, and the beam quality metric comprises an optical energy of the pulsed light beam, a spectral bandwidth of the pulsed light beam, and/or a wavelength of the pulsed light beam.

3. The system of claim 1 , further comprising an optical lithography system configured to receive the pulsed light beam from the optical source, and wherein at least some of the detection modules are configured to receive data related to the pulsed light beam from the optical lithography system.

4. The system of claim 1 , wherein the beam quality metric has only two possible values.

5. The system of claim 1 , wherein
the beam quality metric has a plurality of possible values, the plurality of possible values comprising a first value that indicates that the pulsed light beam does not meet the pre-defined specification,
the monitoring module being configured to analyze the beam quality metric comprises the monitoring module being configured to count occurrences of the first value over a period of time or for a finite number of pulses,
the monitoring module being configured to determine the health status of the gaseous gain medium comprises the monitoring module being configured to compare the count of occurrences to a threshold, and
the produced status signal indicates to end use of the gaseous gain medium if the count of occurrences exceeds the threshold.

6. A system comprising:
an optical source configured to emit a pulsed light beam, the optical source comprising one or more chambers, each of the one or more chambers configured to hold a gaseous gain medium, the gaseous gain medium being associated with an assumed gas life;
at least one detection module configured to:
receive and analyze data related to the pulsed light beam, and
produce a beam quality metric based on the data related to the pulsed light beam, the beam quality metric comprises an optical energy of the pulsed light beam, a spectral bandwidth of the pulsed light beam, and/or a wavelength of the pulsed light beam; and

a monitoring module configured to:
analyze the beam quality metric including determining whether the pulsed light beam meets a pre-determined specification,
determine a health status of the gaseous gain medium based on the analysis of the beam quality metric, and
produce a status signal based on the determined health status, the status signal indicating whether to extend use of the gaseous gain medium beyond the assumed gas life or to end use of the gaseous gain medium,

wherein the at least one detection module comprises a plurality of detection modules, the plurality of detection modules comprising:
a discharge count detection module configured to detect an occurrence of a discharge event in any of the one or more chambers and to produce a signal that indicates a count of discharge events over a period of time;
a bandwidth detection module configured to detect a spectral bandwidth of the pulsed light beam and to produce a signal that indicates a spectral bandwidth of the pulsed light beam;
an energy detection module configured to detect an energy of the pulsed light beam and to produce a signal that indicates an energy of the pulsed light beam;
a wavelength detection module configured to detect a wavelength of the pulsed light beam and to produce a signal that indicates the wavelength of the pulsed light beam; and
a gas detection module configured to detect an amount of a gas mixture injected into the one or more chambers and the produce a signal that indicates the amount of the gas mixture injected, and wherein

each of the bandwidth detection module, the energy detection module, and the wavelength detection module produce a beam quality metric based on, respectively, the signal produced by the bandwidth detection module, the signal produced by the energy detection module, and the signal produced by the wavelength detection module,
the monitoring module analyzes the beam quality metric by analyzing the beam quality metric from the bandwidth detection module, the energy detection module, and the wavelength detection module, and
the monitoring module is configured to determine the health status based on the analyzed beam quality metric, the signal produced by the gas detection module, and the signal produced by the discharge detection module.

7. The system of claim 6 , wherein the plurality of detection modules further comprises a sensor configured to detect fluorine and to produce a signal that indicates a concentration of fluorine in the gaseous gain medium, and the monitoring module is configured to determine the health status based on the signal produced by the sensor.

8. The system of claim 6 , wherein the optical source comprises two chambers, one of the two chambers comprising a master oscillator and the other of the two chambers comprising a power amplifier, and the system further comprises a timing controller configured to control discharge events in the master oscillator and the power amplifier, and the plurality of detection modules further comprises a timing detection module configured to monitor a difference in time between a discharge event in the master oscillator and a discharge event in the power amplifier.

9. The system of claim 8 , wherein the optical source is associated with a plurality of parameters, each of the parameters having an acceptable range of values, and to analyze the produced signals from the plurality of detection modules, the monitoring module is configured to determine whether the beam quality metric in each signal is within the acceptable range of values associated with that parameter.

10. A system comprising:
a lithography system, the lithography system comprising an optical source, the optical source comprising at least one chamber configured to hold a gaseous gain medium, the gaseous gain medium being associated with an assumed gas life; and
a monitoring system comprising:
a monitoring data interface configured to receive information from the lithography system; and
an electronic storage configured to store one or more rules and a library of modules, wherein each of the one or more rules associates an aspect of the gaseous gain medium with at least one module in the library of modules, and the monitoring system is configured to:
access at least one rule,
identify a module from a library of modules based on the accessed rule, and
determine a health status for the gaseous gain medium in the optical source using the identified module and information from the lithography system.

11. The system of claim 10 , wherein the monitoring system is further configured to produce a status signal based on the determined health status, the status signal indicating w

Assignees

• Cymer LLC

Inventors

• Dorobantu Andrei
• Bhaban Shreyas

Classifications

• G03F7/70025 Primary

  by lasers · CPC title

• G03F7/70483

  Information management; Active and passive control; Testing; Wafer monitoring, e.g. pattern monitoring · CPC title

• H01S3/036

  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

• H01S3/097

  by gas discharge of a gas laser · CPC title

• H01S3/10069

  Memorized or pre-programmed characteristics, e.g. look-up table [LUT] · CPC title