Spectral feature selection and pulse timing control of a pulsed light beam

Patent metadata

Field	Value
Publication number	US-11768438-B2
Application number	US-202217971103-A
Country	US
Kind code	B2
Filing date	Oct 21, 2022
Priority date	Mar 30, 2018
Publication date	Sep 26, 2023
Grant date	Sep 26, 2023

Abstract

A method includes driving, while producing a burst of pulses at a pulse repetition rate, a spectral feature adjuster among a set of discrete states at a frequency correlated with the pulse repetition rate; and in between the production of the bursts of pulses (while no pulses are being produced), driving the spectral feature adjuster according to a driving signal defined by a set of parameters. Each discrete state corresponds to a discrete value of a spectral feature. The method includes ensuring that the spectral feature adjuster is in one of the discrete states that corresponds to a discrete value of the spectral feature of the amplified light beam when a pulse in the next burst is produced by adjusting one or more of: an instruction to the lithography exposure apparatus, the driving signal to the spectral feature adjuster, and/or the instruction to the optical source.

First claim

What is claimed is:

1. A method comprising:
while producing a burst of pulses of an amplified light beam at a pulse repetition rate in response to a trigger signal, the amplified light beam supplied to a lithography exposure apparatus, driving a spectral feature adjuster among a set of discrete states, with each discrete state corresponding to a discrete value of the spectral feature of the amplified light beam;
in between the production of the bursts of pulses and while no trigger signal is being received, driving the spectral feature adjuster; and
ensuring that the spectral feature adjuster is in one of the discrete states that corresponds to a discrete value of the spectral feature of the amplified light beam when a pulse in the next burst is produced by one or more of:
adjusting a trigger inter-burst time interval such that an inter-burst time interval is an integer multiple of a time interval between pulses of the amplified light beam;
adjusting one or more parameters associated with driving the spectral feature adjuster in between the production of the bursts of pulses based on an indication from the lithography exposure apparatus about the time at which it will request the production of the next burst;
delaying, for a period of time greater than zero, the production of the next burst of pulses relative to a request from the lithography exposure apparatus to produce the next burst of pulses; and
sending a signal to the lithography exposure apparatus, the signal including information related to how the spectral feature adjuster is being driven in between the production of the bursts of pulses.

2. The method of claim 1 , wherein driving the spectral feature adjuster among the set of discrete states comprises driving the spectral feature adjuster at a frequency correlated with the pulse repetition rate.

3. The method of claim 1 , wherein each discrete value of the spectral feature of the amplified light beam is selected out of a plurality of pre-set discrete values of the spectral feature.

4. The method of claim 1 , wherein the trigger signal is supplied from the lithography exposure apparatus.

5. The method of claim 1 , wherein, in between the production of the bursts of pulses and while no trigger signal is being received, driving the spectral feature adjuster comprises driving the spectral feature adjuster in a periodic manner that is related to information received from the lithography exposure apparatus.

6. The method of claim 5 , wherein driving the spectral feature adjuster in the periodic manner that is related to information received from the lithography exposure apparatus comprises driving the spectral feature adjuster at a frequency that is correlated with the pulse repetition rate.

7. The method of claim 1 , wherein a pulse in the burst that is produced when the spectral feature adjuster is in one of the discrete states has a spectral feature that corresponds to that discrete state.

8. The method of claim 1 , wherein ensuring that the spectral feature adjuster is in one of the discrete states that corresponds to a discrete value of the spectral feature of the amplified light beam when a pulse in the next burst is produced includes adjusting the trigger inter-burst time interval such that the inter-burst time interval is an integer multiple of the time interval between pulses of the amplified light beam; and the inter-burst time interval is the time interval between the last pulse in the burst and the first pulse in the next burst or a pulse that follows the first pulse in the next burst.

9. The method of claim 1 , wherein ensuring that the spectral feature adjuster is in one of the discrete states that corresponds to a discrete value of the spectral feature of the amplified light beam when a pulse in the next burst is produced includes adjusting one or more parameters associated with driving the spectral feature adjuster in between production of the bursts of pulses based on the indication from the lithography exposure apparatus about the time at which it will request production of the next burst; and adjusting one or more parameters associated with driving the spectral feature adjuster in between the production of the bursts of pulses based on the indication from the lithography exposure apparatus about the time at which it will request the production of the next burst comprises modifying one or more of a frequency and a phase of a driving signal associated with the spectral feature adjuster.

10. The method of claim 9 , further comprising, if the frequency at which the spectral feature adjuster is driven is modified due to a mismatch, then changing the frequency at which the spectral feature adjuster is driven at the start of the next burst to be correlated with the pulse repetition rate.

11. The method of claim 1 , wherein ensuring that the spectral feature adjuster is in one of the discrete states that corresponds to a discrete value of the spectral feature of the amplified light beam when a pulse in the next burst is produced includes delaying, for a period of time greater than zero, the production of the next burst of pulses relative to a request from the lithography exposure apparatus to produce the next burst of pulses; and delaying, for a period of time greater than zero, the production of the next burst of pulses relative to the request from the lithography exposure apparatus to produce the next burst of pulses comprises delaying the next burst of pulses until the spectral feature adjuster can be driven to one of the discrete states that corresponds to a discrete value of the spectral feature of the amplified light beam when a pulse in the next burst of pulses is produced.

12. The method of claim 1 , wherein ensuring that the spectral feature adjuster is in one of the discrete states that corresponds to a discrete value of the spectral feature of the amplified light beam when a pulse in the next burst is produced includes sending a signal to the lithography exposure apparatus, the signal including information related to how the spectral feature adjuster is being driven in between the production of the bursts of pulses; the method further comprising receiving an adjusted trigger signal, the adjusted trigger signal being based on the signal sent to the lithography exposure apparatus, the signal including information related to how the spectral feature adjuster is being driven in between the production of the bursts of pulses.

13. The method of claim 12 , wherein the adjusted trigger signal causes an increase in an inter-burst time interval.

14. The method of claim 1 , wherein ensuring that the spectral feature adjuster is in one of the discrete states when the pulse in the next burst is produced comprises ensuring that the spectral feature adjuster is in one of the discrete states when the initial pulse in the next burst is produced.

15. A method comprising:
while producing a burst of pulses of an amplified light beam at a pulse repetition rate in response to a trigger signal, the amplified light beam supplied to a lithography exposure apparatus, driving a spectral feature adjuster among a set of discrete states, with each discrete state corresponding to a discrete value of the spectral feature of the amplified light beam;
in between the production of the bursts of pulses and while no trigger signal is being received, driving the spectral feature adjuster; and
ensuring that the spectral feature adjuster is in one of the discrete states that corresponds to a discrete value of the spectral feature of the amplified light beam when a pulse in the next burst is produced by adjusting a trigger inter-burst time

Assignees

• Cymer LLC

Inventors

• O'Brien Kevin Michael
• Duffey Thomas Patrick
• Thornes Joshua Jon

Classifications

• H01S3/106

  by controlling devices placed within the cavity ({H01S3/10076,} H01S3/13 take precedence) · CPC title

• H01S3/10046 Primary

  Pulse repetition rate control (H01S3/11 takes precedence) · CPC title

• G03F7/70041 Primary

  by pulsed sources, e.g. multiplexing, pulse duration, interval control or intensity control · CPC title

• G03F7/70575

  Wavelength control, e.g. control of bandwidth, multiple wavelength, selection of wavelength or matching of optical components to wavelength · CPC title

• H01S3/073

  Gas lasers comprising separate discharge sections in one cavity, e.g. hybrid lasers (tandem arrangements of separate gas lasers H01S3/2366) · CPC title