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 applying a uniform polishing pressure on a wafer are disclosed. According to one aspect of the present invention, a chemical mechanical planarization polishing apparatus includes a polishing pad, a wafer holder, and a force control system. The wafer holder supports a wafer to be polished using the polishing pad. The polishing pad is arranged to move relative to the wafer holder such that an area of contact between the wafer holder and the polishing pad varies. The force control system including a controller and a plurality of actuators that apply forces to the polishing pad. The controller controls the forces as the area of contact varies to substantially maintain a first polishing pressure on the wafer arranged to be supported by the wafer holder.

Abstract: An apparatus and method for generating a trajectory used in precision lithography, includes receiving first input parameters for a first trajectory and second input parameters for a second trajectory, converting the first input parameters of the first trajectory into a first derivative-jerk and the second input parameters of the second trajectory into a second derivative-jerk. The first and second derivative-jerk are arranged with the first derivative-jerk overlapping the second derivative-jerk by a time interval, and then combining the first derivative-jerk and the second derivative-jerk together into a third derivative-jerk using a shorter period of time compared with the time to finish the combination of the first derivative-jerk and the second derivative-jerk.

Abstract: A stage assembly (10) for moving a device (26) along an X axis and a Y axis includes a stage base (12), a device table (16), a stage mover assembly (18), a measurement system (21), and a control system (22). The stage mover assembly (18) includes a pair X guide movers (82) (84) and a Y table mover (87). The measurement system (21) includes a first X system (100) and a second X system (102). The control system (22) receives the position signals from the measurement system (21) and directs current to the X movers (82) (84) to move the device table along the X axis. The control system (22) can be designed to not skip any servo cycles during switching of position signals.

Abstract: A stage assembly (10) for moving a device (26) along an X axis and a Y axis includes a stage base (12), a device table (16), a stage mover assembly (18), a measurement system (21), and a control system (22). The stage mover assembly (18) includes a pair X guide movers (82) (84) and a Y table mover (87). The measurement system (21) includes a first X system (100) and a second X system (102). The control system (22) receives the position signals from the measurement system (21) and directs current to the X movers (82) (84) to move the device table along the X axis. The control system (22) can be designed to not skip any servo cycles during switching of position signals.

Abstract: A closed-loop system is implemented during startup for accurately determining the magnet offset between a set of magnets and a set of windings of a brushless DC motor. The determined magnetic offset value is used to align a position sensor to the actual angular distance between the windings and the magnets. The alignment of the position sensor setting is in turn used to provide a commutation current that allows the motor to operate at maximum efficiency.