US 11,686,951 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 Apr. 26, 2021, as Appl. No. 17/240,050.
Application 17/240,050 is a continuation of application No. 16/503,073, filed on Jul. 3, 2019, granted, now 11,054,665.
Application 16/503,073 is a continuation of application No. 15/407,153, filed on Jan. 16, 2017, granted, now 10,451,890, issued on Oct. 22, 2019.
Prior Publication US 2021/0239998 A1, Aug. 5, 2021
Int. Cl. G02B 27/48 (2006.01); G01J 3/26 (2006.01); G01J 9/02 (2006.01); G01J 3/02 (2006.01); G03F 7/00 (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)] 20 Claims
OG exemplary drawing
 
1. An apparatus comprising:
an optical source configured to produce a light beam made up of pulses and 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 light beam of pulses and configured to, for each of the pulses in the light beam, modulate an 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; and
a beam directing apparatus in the path of a light beam of pulses formed from the modified pulses, the beam directing apparatus configured to direct the light beam of pulses formed from the modified pulses toward a substrate within a lithography exposure apparatus.