US 12,085,862 B2
Laser system for source material conditioning in an EUV light source
Matthew Ryan Graham, San Diego, CA (US); Spencer Rich, San Diego, CA (US); and Sean W. McGrogan, San Diego, CA (US)
Assigned to ASML Netherlands B.V., Veldhoven (NL)
Appl. No. 17/633,643
Filed by ASML Netherlands B.V., Veldhoven (NL)
PCT Filed Aug. 14, 2020, PCT No. PCT/EP2020/072939
§ 371(c)(1), (2) Date Feb. 8, 2022,
PCT Pub. No. WO2021/028592, PCT Pub. Date Feb. 18, 2021.
Claims priority of provisional application 62/887,160, filed on Aug. 15, 2019.
Prior Publication US 2022/0317576 A1, Oct. 6, 2022
Int. Cl. G03F 7/20 (2006.01); G03F 7/00 (2006.01); H05G 2/00 (2006.01)
CPC G03F 7/70266 (2013.01) [G03F 7/70033 (2013.01); H05G 2/008 (2013.01)] 20 Claims
OG exemplary drawing
 
1. Apparatus for generating extreme ultraviolet radiation using source material, the apparatus being configured to operate in an exposure mode in which the source material is irradiated by pulses and a nonexposure mode in which the source material is not irradiated, the apparatus comprising:
a radiation source configured to generate at least one off-droplet pulse during the nonexposure mode and to generate a plurality of on-droplet pulses during the exposure mode; and
an energy controller configured to perform an energy measurement of the at least one off-droplet pulse during the nonexposure mode and to drive pulse energy to a pulse energy setpoint based at least in part on the energy measurement of the at least one off-droplet pulse, the radiation source bring further configured to generate the on-droplet pulses having an energy at the pulse energy setpoint during the exposure mode.