REDUCING SPECKLE IN AN EXCIMER LIGHT SOURCE
First Claim
1. A method comprising:
- producing a light beam made up of pulses having a wavelength in the deep ultraviolet range, each pulse having a first temporal coherence defined by a first temporal coherence length and each pulse being defined by a pulse duration;
for one or more pulses, modulating the optical phase over the pulse duration of the pulse to produce a modified pulse having a second temporal coherence defined by a second temporal coherence length that is less than the first temporal coherence length of the pulse;
forming a light beam of pulses at least from the modified pulses; and
directing the formed light beam of pulses toward a substrate within a lithography exposure apparatus.
2 Assignments
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Accused Products
Abstract
A method includes: producing a light beam made up of pulses having a wavelength in the deep ultraviolet range, each pulse having a first temporal coherence defined by a first temporal coherence length and each pulse being defined by a pulse duration; for one or more pulses, modulating the optical phase over the pulse duration of the pulse to produce a modified pulse having a second temporal coherence defined by a second temporal coherence length that is less than the first temporal coherence length of the pulse; forming a light beam of pulses at least from the modified pulses; and directing the formed light beam of pulses toward a substrate within a lithography exposure apparatus.
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Citations
44 Claims
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1. A method comprising:
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producing a light beam made up of pulses having a wavelength in the deep ultraviolet range, each pulse having a first temporal coherence defined by a first temporal coherence length and each pulse being defined by a pulse duration; for one or more pulses, modulating the optical phase over the pulse duration of the pulse to produce a modified pulse having a second temporal coherence defined by a second temporal coherence length that is less than the first temporal coherence length of the pulse; forming a light beam of pulses at least from the modified pulses; and directing the formed light beam of pulses toward a substrate within a lithography exposure apparatus. - View Dependent Claims (2, 3, 4, 6, 7, 8, 9, 12, 13, 18, 19)
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5. (canceled)
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10. (canceled)
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11. (canceled)
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14-17. -17. (canceled)
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20-26. -26. (canceled)
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27. An apparatus comprising:
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a light source configured to produce a light beam made up of pulses having a wavelength in the deep ultraviolet range, each pulse having a first temporal coherence defined by a first temporal coherence length and each pulse being defined by a pulse duration; a phase modulator system in the path of the light beam of pulses and configured to, for at least one pulse, modulate the optical phase over the pulse duration of the pulse to produce a modified pulse having a second temporal coherence defined by a second temporal coherence length that is less than the first temporal coherence length; a measurement apparatus configured to measure a characteristic of a test pulse, wherein a test pulse is either a pulse having the first temporal coherence or the modified pulse having the second temporal coherence; and a control system in communication with the measurement apparatus and the phase modulator system, the control system configured to; receive the measured characteristic of the test pulse from the measurement apparatus; determine whether a bandwidth of the modified pulse is within a range of a target bandwidth based on the received measured characteristic; and if it is determined that the bandwidth of the modified pulse is outside the range of the target bandwidth, then adjusting a frequency at which the optical phase over the pulse duration of the pulse that produces the modified pulse is modulated. - View Dependent Claims (28, 30, 33, 34, 35, 36, 37, 38, 39, 41, 43)
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29. (canceled)
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31. (canceled)
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32. (canceled)
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40. (canceled)
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42. (canceled)
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44. An apparatus comprising:
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a phase modulator system in the path of the light beam of pulses having a wavelength in the deep ultraviolet range, the phase modulator system is configured to, for at least one pulse, modulate the optical phase over a pulse duration of the pulse to produce a modified pulse having a second temporal coherence length that is less than a first temporal coherence length of the pulse before it has been modulated; a measurement apparatus configured to measure a characteristic of a test pulse, wherein a test pulse is either a pulse having the first temporal coherence or the modified pulse having the second temporal coherence; and a control system in communication with the measurement apparatus and the phase modulator system, the control system configured to; receive the measured characteristic of the test pulse from the measurement apparatus; determine whether a bandwidth of the modified pulse is within a range of a target bandwidth based on the received measured characteristic; and if it is determined that the bandwidth of the modified pulse is outside the range of the target bandwidth, then adjusting a frequency at which the optical phase over the pulse duration of the pulse that produces the modified pulse is modulated.
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Specification