Patent ID: 8830442
Filing Date: 2014-09-09
Classification: G03F,H01L

Abstract:
1. A servo control system configured to control a position of an object supported by a movable support, the servo control system comprising: a first measurement system configured to measure a position of the movable support; a comparative device configured to determine an error in the position of the movable support based on a comparison between the measured movable support position and a desired movable support position and to output an error signal indicative of the error in the position of the movable support; a controller unit configured to provide a control signal based on the error signal; a slip compensation device configured to compensate a slip between the object and the movable support, the slip compensation device comprising a second measurement system configured to measure a position of the object with respect to the movable support, and an adder configured to add a slip compensation signal to the measured movable support position or the error signal based on the measured object position; and an actuator configured to actuate the movable support based on the control signal to substantially simultaneously correct for the slip between the object and the movable support and the error in the position of the movable support.