Stage system, lithographic apparatus and device manufacturing method

A lithographic apparatus arranged to transfer a pattern from a patterning device onto a substrate, wherein the lithographic apparatus comprises a stage system, the stage system comprising:

• an object table adapted to support an object to be positioned, and
• a positioning system adapted to position the object table, wherein the positioning system comprises an actuator adapted to position the object table in a direction of actuation, the actuator comprises a magnet assembly and a coil assembly, and the magnet assembly comprises a first magnetic body and a second magnetic body,
• wherein the first magnetic body and second magnetic body are, in use, subjected to an internal magnetic force,
• wherein the coil assembly extends at least partly between the first magnetic body and the second magnetic body so as to, in use, generate a force in the direction of actuation,
• wherein the magnet assembly is provided with a first interface which is adapted to connect the first magnetic body to the object table, and with a second interface which is adapted to connect the second magnetic body to the object table, and
• wherein the magnet assembly further comprises a spacer device, which is adapted to hold the first magnetic body and the second magnetic body at a relative distance to each other in at least the direction of the internal magnetic force.

A lithographic apparatus comprising:

• an illumination system configured to condition a radiation beam;
• a support constructed to support a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam;
• a substrate table constructed to hold a substrate;
• and
• a projection system configured to project the patterned radiation beam onto a target portion of the substrate,
• wherein the lithographic apparatus further comprises a positioning system adapted to position the substrate table, the positioning system comprising an actuator adapted to position an object table in a direction of actuation, the actuator comprises a magnet assembly and a coil assembly, and the magnet assembly comprises a first magnetic body and a second magnetic body,
• wherein the first magnetic body and second magnetic body are, in use, subjected to an internal magnetic force,
• wherein the coil assembly extends at least partly between the first magnetic body and the second magnetic body so as to, in use, generate a force in the direction of actuation,
• wherein the magnet assembly is provided with a first interface which is adapted to connect the first magnetic body to the object table, and with a second interface which is adapted to connect the second magnetic body to the object table, and
• wherein the magnet assembly further comprises a spacer device, which is adapted to hold the first magnetic body and the second magnetic body at a relative distance to each other in at least the direction of the internal magnetic force.

A device manufacturing method comprising:

• transferring a pattern from a patterning device onto a substrate using a stage system, the stage system comprising:
• an object table adapted to support an object to be positioned, and
• a positioning system adapted to position the object table, wherein the positioning system comprises an actuator adapted to position the object table in a direction of actuation, the actuator comprises a magnet assembly and a coil assembly, and the magnet assembly comprises a first magnetic body and a second magnetic body,
• wherein the first magnetic body and second magnetic body are, in use, subjected to an internal magnetic force,
• wherein the coil assembly extends at least partly between the first magnetic body and the second magnetic body so as to, in use, generate a force in the direction of actuation,
• wherein the magnet assembly is provided with a first interface which is adapted to connect the first magnetic body to the object table, and with a second interface which is adapted to connect the second magnetic body to the object table, and
• wherein the magnet assembly further comprises a spacer device, which is adapted to hold the first magnetic body and the second magnetic body at a relative distance to each other in at least the direction of the internal magnetic force.