Patent ID: 6400741
Filing Date: 2002-06-04
Classification: H01S

Abstract:
An emission timing control apparatus for a pulsed laser comprising:a magnetic pulse compression circuit including a multi-stage charge transfer circuit comprised of a plurality of magnetic switches connected serially to a charging power source and a plurality of capacitors connected parallel to the charging power source, for compressing current pulses in a plurality of stages using the multi-stage charge transfer circuit; switching means for carrying out a switching operation to connect and disconnect the charging power source to and from the magnetic pulse compression circuit; a laser discharge electrode connected to an output terminal of the magnetic pulse compression circuit; control means for outputting a voltage command value to the charging power source, wherein the laser executing pulsed laser oscillation at a predetermined repetition frequency by turning on the switching means via a pulse oscillation synchronizing signal having the predetermined repetition frequency received from a semiconductor exposure apparatus; reference delay time setting means for setting a predetermined reference delay time, the predetermined reference delay time being greater than a maximum value of a variable range of a real emission delay time from when the switching means is turned on until laser oscillation begins; delay time calculating means for calculating for each pulse oscillation a difference between the predetermined reference delay time for a pulse oscillation corresponding to the voltage command value output from the control means; and delay means for delaying the pulse synchronizing oscillation signal received from the semiconductor exposure apparatus by the time difference calculated in the delay time calculating means and outputting a delayed signal to the switching means.