Actuation systems and lithographic apparatus which address the issue of uncontrolled return of common mode currents are provided. In an embodiment such systems aim to prevent the occurrence of corona and discharge between high voltage electric cables in low pressure environments. An exemplary actuation system includes an actuator module, a power source and power transmission cables. The actuator module includes an electrical motor and a first plurality of shielded cables configured to connect to the electrical motor at one end. The actuator module is located in a low pressure environment and each shield of the first plurality of cables is grounded. The transmission cables electrically connect the first plurality of cables with power supply, and include an extra cable configured to connect each shield of the first plurality of cables with the first extra cable, via a choke so as to provide a return path for common-mode currents.

The invention relates to a lithographic apparatus comprising: an actuation system for positioning an object; a control unit (CU) for controlling the actuation system; and a cooling system for cooling the actuation system, wherein the actuation system comprises a coil assembly (CA) including one or more coils (CO) as force generating members, wherein the cooling system comprises cooling element (CE) interacting with the coil assembly for cooling the coil assembly, and wherein the control unit is configured to control a temperature of the one or more coils to keep a magnitude of cyclic stress below a predetermined value.

A movable stage system is configured to support an object subjected to a lithography process. A short stroke part (SS) is configured to support the object (W) and a long stroke part (LS) is configured to support the short stroke part. The short stroke part is movable over a relative small range of movement with respect to the long stroke part. The long stroke part is movable over a relative large range of movement with respect to a base support arranged to support the long stroke part. A shielding element (SE) is arranged between the short and long stroke parts. A position control system (PCS) maintains a substantially constant distance between the shielding element and the short stroke part.

A vibration isolation system including a support, a forward actuator and a return device. The support is for supporting the body on a base. The support has a body engaging surface and a base engaging surface. The base engaging surface is arranged to couple to the base. The support couples the body engaging surface to the body in a coupled state. The support uncouples the body engaging surface from the body in an uncoupled state. The forward actuator moves the body and the body engaging surface together relatively to the base in a first direction from a first initial position to an end position in the coupled state. The return device is configured to move the body engaging surface relatively to the body opposite to the first direction from the end position to a second initial position in the uncoupled state.

A substrate stage is used in a lithographic apparatus. The substrate stage includes a substrate table constructed to hold a substrate and a positioning device for in use positioning the substrate table relative to a projection system of the lithographic apparatus. The positioning device includes a first positioning member mounted to the substrate table and a second positioning member co-operating with the first positioning member to position the substrate table. The second positioning member is mounted to a support structure. The substrate stage further comprises an actuator that is arranged to exert a vertical force on a bottom surface of the substrate table at a substantially fixed horizontal position relative to the support structure.

A planar motor rotor displacement measuring device and its measuring method are provided. The motor is a moving-coil type planar motor. The device comprises probes, two sets of sine sensors, two sets of cosine sensors, a signal lead wire and a signal processing circuit. The method is arranging two sets of magnetic flux density sensors within a magnetic field pitch τ along two vertical movement directions in the rotor located in the sine magnetic field area. Sampled signals of the four sets of sensors are respectively processed with a frequency multiplication operation, four subdivision signals are obtained, the zero-crossing points of the four subdivision signals are detected, and then two sets of orthogonal pulse signals are generated. The pulse number of the orthogonal pulse signals is counted, and phase difference of the two sets of orthogonal pulse signals is respectively detected.

The present invention provides a computer-readable storage medium which stores a program for causing a computer to generate time-series data of an electric current to be supplied to a motor in order to cause, a control system, including the motor configured to drive an object, to transit from a first state to a second state, the program causing the computer to generate the time-series data so as to satisfy a constraint including a condition to constrain an upper limit value of dispersion of a plurality of state quantities respectively obtained from a plurality of models each of which estimates, from the time-series data, a state quantity of a specific mode of a vibration mode and motion mode of the object, and so that a value of an evaluation function for evaluating the time-series data falls within a tolerance.

A method for positioning a substage (9), supported by a main stage (5), relative to a reference object, the substage moveable in a direction (7) between a first and second position relative to the main stage. The method includes positioning the first stage using a passive force system that is activated by positioning the main stage. The passive force system includes two magnet systems (119, 121), each magnet system being configured to apply a force in the direction to the first stage with respect to the second stage in a non-contact manner, the forces resulting in a resultant force applied to the first stage in the direction by the passive force system. A magnitude and/or a direction of the resultant force depends on the position of the first stage relative to the second stage, and the first stage has a zero-force position between the first and second position in which the resultant force is zero.

An electromagnetic motor is described, the electromagnetic motor comprising: a magnet assembly configured to generate a two-dimensional alternating magnetic field having a pitch Pm1 in a first direction and a pitch Pm2 in a second direction; a coil assembly configured to co-operate with the magnet assembly to generate a first force in the first direction and a second force in the second direction, wherein the coil assembly comprises a first coil set comprising a plurality of first coils for generating the first force and a second coil set comprising a plurality of second coils for generating the second force, wherein a ratio R1 of a coil pitch Pc1 in the first coil set in the first direction over Pm1 is different from a ratio R2 of a coil pitch Pc2 in the second coil set in the second direction over Pm2.

The invention relates to an object positioning system including: an actuator system and a measurement system. The actuator system comprises an actuator made of a material with predominantly electrostrictive properties and substantially no net polarization in absence of an electric field. The actuator system is configured to apply an electric field to the actuator, which electric field comprises a bias electric field and an actuation electric field superimposed on the bias electric field, a field strength of said actuation electric field being equal to or smaller than a field strength of the bias electric field. The measurement system is configured to measure an electrical property of the actuator which is representative for a mechanical state of the actuator. The measurement system comprises a bridge circuit including an actuator and a reference element having electrical properties matched to the electrical properties of the actuator.