ArF and KrF excimer laser apparatus and fluorine laser apparatus for lithography

摘要

The present invention relates to an ArF excimer laser apparatus for lithography capable of stretching the laser pulse width even when the repetition rate exceeds 4 kHz and also relates to a KrF excimer laser apparatus and fluorine laser apparatus for lithography capable of stretching the laser pulse width even when the repetition rate exceeds 2 kHz. In a laser apparatus for lithography having laser discharge electrodes disposed in a laser chamber and a peaking capacitor connected in parallel to the laser discharge electrodes, the period Tn of the waveform of an oscillating current flowing in a first circuit loop formed by the final-stage capacitor of a magnetic pulse compression circuit and the laser discharge electrode and the period Tp of the waveform of an oscillating current flowing in a second circuit loop formed by the peaking capacitor and the laser discharge electrodes satisfy the condition of 5Tp≦Tn, and the period Tn satisfies the condition of Tn250 ns, whereby a laser oscillating operation is performed by at least 2.5 cycles of the oscillating current flowing between the laser discharge electrodes.