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

Patent metadata

Field	Value
Publication number	US-11526083-B2
Application number	US-201916980467-A
Country	US
Kind code	B2
Filing date	Mar 1, 2019
Priority date	Mar 30, 2018
Publication date	Dec 13, 2022
Grant date	Dec 13, 2022

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:
producing a burst of pulses of an amplified light beam at a pulse repetition rate and directing the pulses to a lithography exposure apparatus;
while producing the pulse burst, driving a spectral feature adjuster among a set of discrete states at a frequency correlated with the pulse repetition rate, with each discrete state corresponding to a discrete value of the spectral feature of the amplified light beam out of a plurality of pre-set discrete values of the spectral feature, such that, each time a pulse in the burst is being produced, the spectral feature adjuster is in one of the discrete states and the amplified light beam pulse has a spectral feature that corresponds to that discrete state;
in between the production of the bursts of pulses and while no pulses are being produced, driving the spectral feature adjuster in a manner that is related to information received from the lithography exposure apparatus; 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.

2. The method of claim 1 , wherein driving the spectral feature adjuster in the manner that is related to information received from the lithography exposure apparatus comprises driving the spectral feature adjuster at a frequency correlated with the pulse repetition rate.

3. The method of claim 2 , wherein ensuring that the spectral feature adjuster is in the discrete state when the pulse in the next burst is produced comprises adjusting an inter-burst time interval so that the inter-burst time interval is an integer multiple of the time interval between pulses for the pulse repetition rate.

4. The method of claim 2 , wherein ensuring that the spectral feature adjuster is in the discrete state when the pulse in the next burst is produced comprises:
receiving an indication from the lithography exposure apparatus about the time at which it will request the production of the next burst;
determining whether the received indication indicates a mismatch in time between the production of the first pulse in the next burst and the time at which the spectral feature adjuster is in the discrete state; and
if the received indication indicates a mismatch in time between the production of the first pulse in the next burst and the time at which the spectral feature adjuster is in the discrete state, then modifying one or more of a frequency and a phase of a driving signal associated with driving the spectral feature adjuster based on the received indication.

5. 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; or
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 and while no pulses are being produced.

6. The method of claim 1 , wherein:
driving the spectral feature adjuster in the manner that is related to information received from the lithography exposure apparatus comprises driving the spectral feature adjuster according to one or more fixed parameters and receiving a request from the lithography exposure apparatus to produce the next burst of pulses; and
ensuring that the spectral feature adjuster is in a discrete state when the pulse in the next burst is produced comprises delaying, for a period of time greater than zero, the production of the next burst of pulses relative to the receipt of the request from the lithography exposure apparatus to produce the next burst of pulses.

7. The method of claim 1 , wherein:
the spectral feature of the amplified light beam is a wavelength of the amplified light beam, and
driving the spectral feature adjuster among the set of discrete states at the frequency correlated with the pulse repetition rate comprises:
driving the spectral feature adjuster so that the wavelength of the amplified light beam changes for each pulse of the amplified light beam between two distinct wavelengths; or
driving the spectral feature adjuster so that the wavelength of the amplified light beam changes for every other pulse of the amplified light beam between two distinct wavelengths.

8. The method of claim 1 , wherein driving the spectral feature adjuster among the set of discrete states comprises driving the spectral feature adjuster according to a sinusoidal drive signal.

9. The method of claim 1 , wherein the information from the lithography exposure apparatus that is related to the manner in which the spectral feature adjuster is driven in between the production of the bursts of pulses and while no bursts of pulses are being produced is received prior to the end of the burst or in between the production of the bursts of pulses.

10. An apparatus comprising:
a spectral feature adjuster; and
an optical apparatus comprising an optical source, the optical apparatus being in communication with the spectral feature adjuster, and configured to:
communicate with a lithography exposure apparatus;
using the optical source, produce a burst of pulses of an amplified light beam at a pulse repetition rate for use by the lithography exposure apparatus for patterning a substrate;
while producing the pulse burst, drive the spectral feature adjuster among a set of discrete states at a frequency correlated with the pulse repetition rate, with each discrete state corresponding to a discrete value of the spectral feature of the amplified light beam out of a plurality of pre-set discrete values of the spectral feature, such that, each time a pulse in the burst is being produced, the spectral feature adjuster is in one of the discrete states and the amplified light beam pulse has a spectral feature that corresponds to that discrete state;
in between the production of the bursts of pulses and while no pulses are being produced, drive the spectral feature adjuster in a manner that is related to information received from the lithography exposure apparatus; and
ensure 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.

11. The apparatus of claim 10 , wherein the spectral feature of the amplified light beam is a wavelength of the amplified light beam.

12. The apparatus of claim 10 , wherein the optical apparatus includes a control apparatus in communication with the spectral feature adjuster, and configured to:
receive indications from the lithography exposure apparatus including the pulse repetition rate; and
send a driving signal to a drive actuator associated with the spectral feature adjuster, wherein the driving signal is based on information received from the lithography exposure apparatus.

13. The apparatus of claim 12 , wherein the driving signal sent to the drive actuator is a sinusoidal driving signal.

14. The apparatus of claim 10 , wherein the spectral feature adjuster optically interacts with a pre-cursor light beam.

15. The apparatus of claim 10 , wherein the optical apparatus comprises:
a first gas discharge stage configured to generate a first pulsed light beam, the first gas discharge stage includes a first gas discharge chamber housing an energy source and containing a gas mixture that includes a

Assignees

• Cymer LLC

Inventors

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

Classifications

• H01S3/2308

  Amplifier arrangements, e.g. MOPA · CPC title

• H01S3/10046 Primary

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

• H01S3/137

  for stabilising of frequency · 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

• H01S3/106

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