Laser system for source material conditioning in an EUV light source
US12085862B2 · kind B2 · utility
0Cited by
6References
20Claims
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Key dates
| Filing date | Aug 14, 2020 |
| Grant date | Sep 10, 2024 |
| Priority date | — |
| Expiry date | Jan 2, 2041 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05G2/0084
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Disclosed is an apparatus and a method in which off-droplet measurements instead of on-droplet measurements of prepulse energy are used for pulse energy control. Prepulse energy is measured during an off-droplet nonexposure period and controlled to a prepulse energy setpoint. The prepulse energy can then be controlled open-loop to the prepulse energy setpoint during on-droplet periods. This effectively decouples the EUV dose control loop from the prepulse energy control loop and avoids negative side effects of coupling such loops, for example, loss of the part of the dose adjustment range available to the dose controller.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.