US 11,054,665 B2
Reducing speckle in an excimer light source
Wilhelmus Patrick Elisabeth Maria op 't Root, Nederweert (NL); Thomas Patrick Duffey, San Diego, CA (US); Herman Philip Godfried, Amsterdam (NL); Frank Everts, Eindhoven (NL); Joshua Jon Thornes, San Diego, CA (US); and Brian Edward King, San Diego, CA (US)
Assigned to Cymer, LLC, San Diego, CA (US); and ASML Netherlands B.V., Veldhoven (NL)
Filed by Cymer, LLC, San Diego, CA (US); and ASML Netherlands B.V., Veldhoven (NL)
Filed on Jul. 3, 2019, as Appl. No. 16/503,073.
Application 16/503,073 is a continuation of application No. 15/407,153, filed on Jan. 16, 2017, granted, now 10,451,890.
Prior Publication US 2019/0324286 A1, Oct. 24, 2019
Int. Cl. G02B 27/48 (2006.01); G01J 3/26 (2006.01); G01J 9/02 (2006.01); G01J 3/02 (2006.01); G03F 7/20 (2006.01); H01S 3/225 (2006.01); H01S 3/00 (2006.01); G01J 11/00 (2006.01); G02F 1/01 (2006.01); H01S 4/00 (2006.01); G02B 19/00 (2006.01)
CPC G02B 27/48 (2013.01) [G01J 3/027 (2013.01); G01J 3/26 (2013.01); G01J 9/02 (2013.01); G01J 11/00 (2013.01); G02F 1/0121 (2013.01); G03F 7/70008 (2013.01); G03F 7/70041 (2013.01); G03F 7/7055 (2013.01); H01S 3/0085 (2013.01); H01S 3/225 (2013.01); H01S 4/00 (2013.01); G01J 2009/0211 (2013.01); G02B 19/0095 (2013.01); G02F 2203/18 (2013.01); G03F 7/70025 (2013.01); G03F 7/70583 (2013.01); H01S 3/0057 (2013.01)] 21 Claims
OG exemplary drawing
 
1. An optical source comprising:
a first stage light source configured to produce a seed light beam made up of pulses and including a spectral tuning apparatus configured to tune one or more spectral features of the seed light beam, each pulse 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 coherence reduction system in the path of the seed light beam pulses and configured to, for each pulse of the seed light beam, produce a modified seed light beam pulse having a second temporal coherence defined by a second temporal coherence length that is less than the first temporal coherence length; and
a second stage optical amplifier including a resonator and a gain medium, the second stage optical amplifier configured to receive the modified seed light beam pulses output from the coherence reduction system, and to produce a light beam made up of amplified pulses.