In laser-produced plasma (LPP) extreme ultraviolet (EUV) systems, pressure waves and other impulsive disturbances originating from plasma bubble emitting EUV light are created which affect flight of incoming droplets. These disturbances slow the migration of subsequent droplets to the plasma bubble. Because the incoming droplets are slowed, the laser beam does not directly hit the droplet at a primary focus point. This causes the resulting level of EUV light generated to be lower than expected and is manifested as a periodic oscillation in the LPP EUV system. An iterative learning controller (ILC) is used to reduce the periodic oscillations when operating the LPP EUV system in a burst mode or a continuous mode. The ILC, on the rising edge of each burst, uses an error signal collected during a completed burst and the input control signal from the completed burst to update the input control signal for a next burst.
