ACTIVE SPECTRAL CONTROL OF DUV LIGHT SOURCE

PROBLEM TO BE SOLVED: To provide a technique for active control of bandwidth in a DUV gas discharge laser system used in a line narrowed application as a laser light source for integrated circuit manufacturing in photolithography.SOLUTION: A line narrowed high average power high pulse repetition laser micro-photolithography light source bandwidth control method and apparatus are disclosed that can include: a bandwidth metrology module measuring the bandwidth of a laser output light pulse beam pulse produced by a light source and providing a bandwidth measurement; a bandwidth error signal generator receiving the bandwidth measurement and a bandwidth set point and providing a bandwidth error signal; and an active bandwidth controller providing a fine bandwidth correction actuator signal and a coarse bandwidth correction actuator signal responsive to the bandwidth error.