Variable reluctance device, stage apparatus, lithographic apparatus and device manufacturing method

摘要

A variable reluctance device includes first and second magnetic members, a coil, a measurement coil, and a control unit. The first and second magnetic members are displaceable relative to each other to provide a magnetic circuit having a variable reluctance. The coil for, in use, receiving a current for generating a magnetic flux through the magnetic circuit. The measurement coil for generating a measurement signal representative of the magnetic flux through the magnetic circuit, whereby the measurement coil is arranged to substantially enclose the magnetic flux through the magnetic circuit. The control unit arranged to receive the flux signal at an input terminal and, in response, provide a control signal based on the measurement signal at an output terminal for controlling an amplitude of the current or a force of a further device. The device can e.g., be applied in a stage apparatus or a lithographic apparatus.

主权项

1. A stage apparatus for positioning an object, the apparatus comprising:
an object table configured to receive the object; a base configure to support the object table; a variable reluctance device configured to position the object table relative to the base, comprising:
first and second magnetic members that are displaceable relative to each other and are configured to provide a magnetic circuit having a variable reluctance,a coil configured to, in use, receive a current for generating a magnetic flux through the magnetic circuit,a measurement coil configured to generate a measurement signal representative of the magnetic flux through the magnetic circuit, anda control unit arranged to receive the measurement signal at an input terminal and, in response, to provide a control signal based on the measurement signal at an output terminal; and a second device configured to position the object table, wherein the control signal is passed through a low-pass filter to generate a first filtered signal and is passed through a high-pass filter to generate a second filtered signal, wherein the first filtered signal is applied to control a current of the variable reluctance device and the second filtered signal is applied to control a force provided by the second device.