Invention Grant
- Patent Title: Systems and methods for stabilization of droplet-plasma interaction via laser energy modulation
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Application No.: US14824280Application Date: 2015-08-12
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Publication No.: US09832854B2Publication Date: 2017-11-28
- Inventor: Daniel Jason Riggs , Robert Jay Rafac
- Applicant: ASML Netherlands B.V.
- Applicant Address: NL Veldhoven
- Assignee: ASML Netherlands B.V.
- Current Assignee: ASML Netherlands B.V.
- Current Assignee Address: NL Veldhoven
- Agency: Gard & Kaslow LLP
- Main IPC: H05G2/00
- IPC: H05G2/00 ; G01J1/42

Abstract:
In a laser produced plasma (LPP) extreme ultraviolet (EUV) system, a droplet is irradiated by a laser pulse to produce a plasma in a chamber. This generates forces that cause the plasma to destabilize and subsequent droplets to have their flight trajectory and speed altered as they approach the plasma. This destabilization is detectable from oscillations in the amount of EUV energy generated. To reduce the oscillations by stabilizing the plasma and travel of the droplets, a proportional-integral (PI) controller algorithm is used to modify an energy of subsequent laser pulses based on the EUV energy generated in the chamber. By modifying the energy of subsequent laser pulses, the plasma stabilizes, which reduces effects on droplet flight and stabilizes the amount of EUV energy generated, allowing the plasma chamber to operate for longer intervals and to lower the amount of reserve power maintained by a laser source.
Public/Granted literature
- US20170048959A1 SYSTEMS AND METHODS FOR STABILIZATION OF DROPLET-PLASMA INTERACTION VIA LASER ENERGY MODULATION Public/Granted day:2017-02-16
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