Compact excimer lasers for metrology and inspection applications

摘要

The compact class of excimer lasers has been developed originally for the ophthalmology (vision correction). These table-top excimer lasers have output energies below 50 mJ, typically up to 20 mJ depending on the emitted wavelength. Due to the continual development in the recent years these laser systems are now available with lifetimes of some billion pulses and repetition rates up to two kHz. All commercially used wavelengths between 351 nm and 157 nm are realized in this laser class. For generating the high voltage pulses to initiate the laser emission a solid state pulsed power module (SSPPM) is installed. This module has a nearly unlimited lifetime. Further work is done to enlarge the life time of all sub-modules especially of the laser tube and the resonator optics. These laser systems can be applied as light sources in metrology and inspection systems especially for the lithography. The state of the art of compact excimer lasers will be presented and especially the results at 193 nm and 157 nm will be discussed. An outlook of the future trends of development of compact excimer lasers will be given, too.