Abstract: Embodiments of the invention relate to a cable force feedforward approach that takes into account the cable force in the counter-mass trajectory computation to reduce or eliminate vibration of the lens body caused by the cable force disturbance and corrective force exerted by the trim motors. In one embodiment, a method provides cable force feedforward control for a counter-mass of a stage with a cable connected to the counter-mass and using the cable force feedforward control to control one or more trim motors to produce a trim motor output force to be applied to the counter-mass, the counter-mass moving in response to a reaction force from movement of the stage.

Abstract: Methods and apparatus for actively damping vibrations associated with a optical assembly of a photolithographic system are disclosed. According to one aspect of the present invention, an assembly that provides damping to a structure of a photolithographic apparatus that is subject to structural oscillations includes a counter mass, an active mechanism, an a controller. The active mechanism is coupled to the structure, supports the counter mass, and applies a force to the structure to counteract structural oscillations in the structure. The controller controls the force applied by the active mechanism on the structure, and utilizes information associated with movement of the structure to control the force.

Abstract: Embodiments of the invention relate to a cable force feedforward approach that takes into account the cable force in the counter-mass trajectory computation to reduce or eliminate vibration of the lens body caused by the cable force disturbance and corrective force exerted by the trim motors. In one embodiment, a method provides cable force feedforward control for a counter-mass of a stage with a cable connected to the counter-mass and using the cable force feedforward control to control one or more trim motors to produce a trim motor output force to be applied to the counter-mass, the counter-mass moving in response to a reaction force from movement of the stage.

Abstract: A precision assembly (10) includes a stage assembly (220) having a first stage (208), a first mover assembly (210) and a control system (24). The first mover assembly (210) moves the first stage (208) during a first iteration (300) and a subsequent second iteration (302) having a similar movement to the first iteration (300). The first iteration (300) generates positioning data that is sent to the control system (24) to control the first mover assembly (210) to adjust movement of the first stage (208) during the second iteration (302) based on at least a portion of the positioning data from the first iteration (300). The positioning data can include the position of the first stage (208) along a first axis, a second axis and/or a third axis. The stage assembly can also include a second stage (206) and a second mover assembly (204) that moves the second stage (206) synchronously with the first stage (208).

Abstract: A method and apparatus minimizes the relative difference between motions of two stages driven by a single input signal, where the motions of the two stages ideally are perfectly synchronized. In practice, synchronization is imperfect due to mechanical/environmental disturbances in each stage as well as electrical differences affecting the stage controller. The two stages are serially coupled for control purposes so that a signal indicating the position of the first stage is used as an input driving signal to the second stage. The relative location error between the two stages is thereby minimized, compared to the case where the two stages are driven simultaneously but in parallel by a common input signal. Furthermore, by using the lower bandwidth stage as the driver (first) stage and the higher bandwidth stage as the follower (second) stage, the relative position error is no larger than the smaller of the absolute position errors of either stage alone.