CPC G01P 5/20 (2013.01) [G02B 27/0006 (2013.01); G03F 1/42 (2013.01); G03F 7/20 (2013.01); G03F 7/70025 (2013.01); G03F 7/70033 (2013.01); H05G 2/005 (2013.01); H05G 2/008 (2013.01)] | 6 Claims |
1. An apparatus for monitoring flow parameters of particles in an extreme ultraviolet light source of an extreme ultraviolet lithography system, comprising:
a droplet detection module configured to detect light reflected and/or scattered from a metal droplet; and
a controller coupled to the droplet detection module and configured to:
perform particle image velocimetry to monitor one or more flow parameters inside the extreme ultraviolet light source.
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