Yoshiho Amada

Stability of krypton fluoride laser in real stepper mode operation

The stable performance of the line-narrowed Krypton Fluoride Excimer Laser for production steppers, the KLES-G6, in real stepper mode operation is presented. Wavelength stability of < +/- 0.1 pm and pulse-to-pulse energy stability of < 2% ((sigma) ) were achieved in the real stepper mode operation. Further the durability test was made at 6 W(10 mJ, 600 Hz) in 1 sec. ON - 1 sec. OFF (50%) burst mode and in cw mode. The central wavelength stability < +/- 0.2 pm including the drift at the head of burst, spectral bandwidth < 1.5 pm, and pulse-to-pulse energy stability < 2.5% ((sigma) ) over 1.6 X 109 shots were achieved. The KLES-G6 will assist us to utilize the excimer stepper in real commercial production successfully.

Narrow band KrF excimer laser for mass production of ULSI ICs

A narrow band KrF excimer laser system for lithography has been developed. Its durability has been proved up to 2 billion shots that correspond to one year operation in mass production line. The system has kept the average power of 6W with the power stability within +- 3% and the spectral line-width 1.2 pm (FWHM) with the wavelength stability within +- 0.2 pm. The integration of the spectrum has indicated that 95% of the spectral energy lay inside 4.6 pm band during 2 billion shots

Recent advances of a KrF excimer laser on a plant's practical requirements

In this paper we describe the performance of the newest model of line-narrowed KrF excimer laser KLES-G6 (1995 model) developed in factory on the practical requirements. The KLES- G6 exhibits: (1) spectral bandwidth < 0.8 pm; (2) wavelength stability < +/- 0.1 pm; (3) pulse-to-pulse energy stability < 1.8% ((sigma) ); (4) output power equals 6 W at 600 Hz; (5) gas life > 100 million pulses or 7 days; (6) window cleaning or exchange > 1 billion pulses; (7) laser chamber exchange > 2 billion pulses; (8) mean time between failures > 1500 hours; (9) running cost per a billion pulses is about 29 thousand dollars. These advanced performances will save the running cost and guarantee the high uptime ratio needed to satisfy the plants practical requirements.