open access

https://hdl.handle.net/2115/8471

High-repetition-rate (6 kHz) and long-pulse-duration (50 ns) ArF excimer laser for sub-65 nm lithography

英語

2006-03

American Institute of Physics

Review of Scientific Instruments

77(3)

035109-1-035109-6

Development of high-repetition-rate ArF excimer lasers is vital requirement for achieving high throughput and high energy-dose stability in a scanner system. ArF　excimer laser, with increasing light pulse duration, can reduce the peak power without the energy-dose change. Then, the spectral bandwidth ΔλFWHM becomes narrower by increasing the number of light round trips in a cavity, and optical damage is reduced from high-peak power. Laser operation exceeding 4 kHz is needed for next-generation technologies that can enable high numerical aperture and development of high-throughput scanners. In the present work, we examined the possibilities of achieving a repetition rate to 6 kHz from 4 kHz in the ArF laser the authors developed, taking the following innovations. The spatial width of discharge region was reduced by about 30%. The uniform gas flow condition between the electrodes was obtained by improving gas flow guides. As a result, we have obtained an average power of 42 W, a standard deviation for pulse-to-pulse energy of 3.5%, and an integral-square pulse width Tis of 44 ns at 6 kHz for ΔλFWHM<0.40 pm. Finally, it was concluded that developing a 6 kHz ArF excimer laser for the next-generation sub-65 nm lithography is feasible.

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Copyright © 2006 American Institute of Physics

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