Patent ID: 6757315
Filing Date: 2004-06-29
Classification: G03F,H01S

Abstract:
An excimer or molecular fluorine laser system, comprising:a discharge chamber containing a gas mixture; a first and a second spaced apart main discharge electrodes having a discharge area therebetween within the discharge chamber, the first main discharge electrode being maintained at ground potential; a pulsed power supply unit for applying electrical pulses to the second main discharge electrode for producing discharges between the first and second main discharge electrodes for energizing the gas mixture; a resonator for generating a laser beam; at least one preionization unit disposed within the discharge chamber for preionizing the gas mixture within the discharge area prior to application of the electrical pulses to the main discharge electrodes, the preionization unit including first and second preionization electrodes having a bushingless dialectric tube surrounding the first preionization electrode, said second preionization electrode being electrically connected to said second main discharge electrode; and an electrical circuit coupled between the first preionization electrode and ground potential, such that a potential difference applied across the first and second preionization electrodes is substantially less than is applied across the first and second main discharge electrodes by the electrical pulses supplied by the pulsed power supply unit, such that both over-flashing and electrical oscillations from residual energies stored in the bushingless dielectric tube are reduced.