Lithographic apparatus and device manufacturing method

A lithographic apparatus comprising:

• a projection system constructed and arranged to project a beam of radiation;
• a vacuum chamber containing at least part of a path of the beam;
• a movable table constructed and arranged to transport an object to a position in the beam path in the vacuum chamber;
• a first capacitor electrode and a second capacitor electrode attached to the table:
• a first inductor assembly coupled to the first capacitor electrode and the second capacitor electrode, and configured to apply a voltage between the first capacitor electrode and the second capacitor electrode;
• an electronic processing circuit;
• a plurality of second inductor assemblies, each with terminals coupled to the electronic processing circuit and being positioned along a path of movement of the table, each second inductor assembly being mounted at a respective position that remains fixed, wherein each second inductor assembly of the plurality of second inductor assemblies being configured to generate a magnetic field in response to applying a voltage on the second inductor assembly which will result in a magnetic field which when picked up by the first inductor assembly will create a magnetic field response in the first inductor assembly dependent on the capacitance of the capacitor electrodes,
• wherein the electronic processing circuit determines parameters that are representative of an impedance across terminals of each of the plurality of second inductor assemblies to detect presence of the object if any one of the plurality of second inductor assemblies exhibits a resonance at a frequency corresponding to presence of the object.

A device manufacturing method comprising:

• moving an object on a table to a position in a beam path in a vacuum chamber by using a plurality of first inductor assemblies positioned along a path of movement of the table, each first inductor assembly configured to have a different inductance value such that the resonance frequencies of different ones of the plurality of first inductor assemblies are mutually different in the presence of the object over first and second capacitor electrodes attached to the table, wherein a first inductor assembly of the plurality of first inductor assemblies coupled to the first capacitor electrode and the second capacitor electrode;
• picking up a magnetic field adjacent the table with the first inductor assembly and applying a voltage with a waveform that follows the waveform of the magnetic field, said voltage being generated with the picked up magnetic field between the first capacitor electrode and the second capacitor electrode;
• inducing variations of the magnetic field with the first inductor assembly, dependent on current flowing between the first capacitor electrode and the second capacitor electrode;
• inducing the magnetic field adjacent the table at least partly from a second inductor assembly mounted at a position that remains fixed, wherein magnetic field lines generated by current through the first inductor assembly affects the magnetic field;
• and
• picking up the variations induced by the first inductor assembly with the second inductor assembly.