US 12,302,484 B2
Droplet generator and method of servicing extreme ultraviolet imaging tool
Wei-Chih Lai, Changhua County (TW); Han-Lung Chang, Kaohsiung (TW); Bo-Tsun Liu, Taipei (TW); Li-Jui Chen, Hsinchu (TW); and Po-Chung Cheng, Chiayi County (TW)
Assigned to TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY, LTD., Hsinchu (TW)
Filed by TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY, LTD., Hsinchu (TW)
Filed on Jun. 30, 2022, as Appl. No. 17/855,655.
Application 17/855,655 is a division of application No. 16/178,157, filed on Nov. 1, 2018, granted, now 11,617,255.
Claims priority of provisional application 62/586,679, filed on Nov. 15, 2017.
Prior Publication US 2022/0338336 A1, Oct. 20, 2022
Int. Cl. H05G 2/00 (2006.01); G03F 7/00 (2006.01)
CPC H05G 2/008 (2013.01) [G03F 7/70033 (2013.01); H05G 2/006 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method of servicing an extreme ultraviolet lithography tool, wherein the extreme ultraviolet lithography tool, comprises:
an extreme ultraviolet radiation source comprising:
a vacuum chamber containing a vacuum atmosphere; and
a droplet generator configured to generate droplets of a molten metal located on a first side of the vacuum chamber, the droplet generator comprising:
a reservoir for a molten metal;
a nozzle having a first end connected to the reservoir and a second opposing end where molten metal droplets emerge from the nozzle; and
an isolation valve at the second end of the nozzle configured to isolate the droplet generator from the vacuum chamber,
the method comprising:
sensing a pressure in the vacuum chamber;
closing the isolation valve to isolate the nozzle from an atmosphere of the vacuum chamber when the pressure in the vacuum chamber exceeds a first threshold pressure;
initiating an inert gas flow to the nozzle;
activating an uninterruptible power supply to power a heating element connected to the nozzle;
wherein the closing the isolation valve, initiating the inert gas flow, and activating the uninterruptible power supply occurs substantially simultaneously;
increasing the pressure in the vacuum chamber so it is no longer a vacuum atmosphere;
opening the vacuum chamber;
performing maintenance on one or more components in the vacuum chamber;
heating the nozzle while performing maintenance on one or more components in the vacuum chamber to maintain the molten metal in a molten state;
restoring the vacuum atmosphere in the vacuum chamber; and
opening the isolation valve, thereby exposing the nozzle to the vacuum chamber atmosphere.