METHOD FOR LPP DRIVE LASER OUTPUT DURING EUV NON-OUTPUT PERIODS

摘要

PROBLEM TO BE SOLVED: To provide an EUV light source with subsystems for maintaining LPP drive laser output during EUV non-output periods.SOLUTION: A device is disclosed herein which comprises: a droplet generator producing droplets of a target material; a sensor providing an intercept time signal when a droplet reaches a preselected location; a delay circuit coupled with the sensor, the delay circuit generating a trigger signal delayed from the intercept time signal; a laser source responsive to a trigger signal to produce a laser pulse; and a system controlling the delay circuit to provide a trigger signal delayed from the intercept time by a first delay time to generate a light pulse that is focused on a droplet, and provide a trigger signal delayed from the intercept time by a second delay time to generate a light pulse which is not focused on a droplet.SELECTED DRAWING: Figure 1