Six to ten KHz, or greater gas discharge laser system
US6914919B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 28, 2002 |
| Grant date | Jul 5, 2005 |
| Priority date | — |
| Expiry date | Mar 31, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01S3/2366
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The present invention provides gas discharge laser systems capable of reliable long-term operation in a production line capacity at repetition rates in the range of 6,000 to 10,0000 pulses power second. Preferred embodiments are configured as KrF, ArF and F2 lasers used for light sources for integrated circuit lithography. Improvements include a modified high voltage power supply capable for charging an initial capacitor of a magnetic compression pulse power system to precise target voltages 6,000 to 10,0000 times per second and a feedback control for monitoring pulse energy and determining the target voltages on a pulse-by-pulse basis. Several techniques are disclosed for removing discharge created debris from the discharge region between the laser electrodes during the intervals between discharges. In one embodiment the width of the discharge region is reduced from about 3 mm to about 1 mm so that a gas circulation system designed for 4,000 Hz operation could be utilized for 10,000 Hz operation. In other embodiments the gas flow between the electrodes is increased sufficiently to permit 10,000 Hz operation with a discharge region width of 3 mm. To provide these substantial increa…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.