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7 July 1997 ArF excimer laser for 193-nm lithography
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The ArF excimer laser light source will extend the optical lithography to below 0.18 micrometers design rules. Still under discussion is the most effective layout of the stepper or scanner imaging optics. The decision for an all-fused-silica lens, an achromatic lens using CaF2, or a catadioptric imaging system has great impact on the laser-bandwidth requirement. In addition, the potential performance and perspective of the laser must be considered in the system layout of the production stepper or step and scan tool. Cost effective operation of such a lithography tool requires a 193 nm excimer laser with high power and repetition rates in the order of 1 kHz or higher. Precise dose control of the exposure demands high repetition rate and excellent stability of the laser output energy. We have developed an ArF laser which can be operated with up to 800 Hz repetition rate based on NovaTubeTM technology. Optimized materials and discharge configurations have been used to achieve laser tube lifetimes above 109 pulses. Up to 4 X 109 pulses tube lifetime have been achieved in beta-site tests. Gas lifetime of several 107 laser pulses is obtained. A solid-state switch has been adapted for the reliable and cost efficient excitation of the 193 nm lithography laser. To achieve laser output of different bandwidths various resonator arrangements have been investigated. The paper gives an overview of the currently achievable power levels at different bandwidths and discusses future trends.
© (1997) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Uwe Stamm, Juergen Kleinschmidt, Peter Heist, Igor Bragin, Rainer Paetzel, and Dirk Basting "ArF excimer laser for 193-nm lithography", Proc. SPIE 3051, Optical Microlithography X, (7 July 1997);


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