Lithographic apparatus and method for calibrating the same

A lithographic apparatus comprising:

• a substrate table configured to hold a substrate;
• an illuminator configured to condition a beam of radiation;
• a support structure configured to support a patterning device that imparts a desired pattern to the beam of radiation;
• a projection system configured to project the patterned beam onto a target portion of the substrate;
• and
• a motion control system configured to control a movement of the substrate table, the motion control system comprising a plurality of position detectors that detect a position of the substrate table, at least three of the position detectors each including a single or multi-dimensional optical encoder to provide at least six position values, the optical encoders being coupled to the substrate table at different locations within a three dimensional coordinate system,
• wherein at least one position value is provided for each dimension of the three dimensional coordinate system,
• wherein the motion control system is configured to calculate the position of the substrate table within the three dimensional coordinate system from a subset of at least three of the six position values and to calculate an orientation of the substrate table with respect to the three dimensional coordinate system from another subset of at least three of the six position values,
• wherein the optical encoders comprise:
• a first two-dimensional optical encoder configured to provide position values in a first and a third dimension of the three dimensional coordinate system, the first optical encoder being coupled to a first side of the substrate table that is substantially parallel to the first dimension;
• a second two-dimensional optical encoder configured to provide position values in a second and the third dimension of the three dimensional coordinate system, the second optical encoder being coupled to a second side of the substrate table that is substantially parallel to the second dimension;
• a third two-dimensional optical encoder coupled to a third side of the substrate table that is substantially parallel to the first dimension and opposite to the first side, and
• a fourth, one-dimensional optical encoder configured to provide a position value in the third dimension, the fourth optical encoder being coupled to a fourth side of the substrate table, the fourth side being substantially parallel to the second dimension and opposite to the second side.

A lithographic apparatus comprising:

• a substrate table configured to hold a substrate;
• an illuminator configured to condition a beam of radiation;
• a support structure configured to support a patterning device that imparts a desired pattern to the beam of radiation;
• a projection system configured to project the patterned beam onto a target portion of the substrate;
• and
• a motion control system configured to control a movement of the substrate table, the motion control system comprising a plurality of position detectors that detect a position of the substrate table, at least three of the position detectors each including a single or multi-dimensional optical encoder to provide at least six position values, the optical encoders being coupled to the substrate table at different locations within a three dimensional coordinate system,
• wherein at least one position value is provided for each dimension of the three dimensional coordinate system,
• wherein the motion control system is configured to calculate the position of the substrate table within the three dimensional coordinate system from a subset of at least three of the six position values and to calculate an orientation of the substrate table with respect to the three dimensional coordinate system from another subset of at least three of the six position values,
• wherein the optical encoder comprises a diffraction-type encoder comprising:
• a light beam generator constructed for generating a light beam,
• a first grating, and
• a second grating, the second grating being movable with respect to the first grating, and a detector arranged to detect a diffracted beam of the light beam as diffracted on the first and the second grating, one of the gratings being mechanically connected to the substrate table, the other one of the gratings being mechanically coupled to a reference base of the lithographic apparatus,
• wherein a movement of the substrate table causes a movement of the first grating with respect to the second grating and in operation causing a change in the diffracted beam.

A lithographic apparatus comprising:

• a substrate table configured to hold a substrate;
• an illuminator configured to condition a beam of radiation;
• a support structure configured to support a patterning device that imparts a desired pattern to the beam of radiation;
• a projection system configured to project the patterned beam onto a target portion of the substrate;
• and
• a motion control system configured to control a movement of the substrate table, the motion control system comprising a plurality of position detectors that detect a position of the substrate table, at least three of the position detectors each including a single or multi-dimensional optical encoder to provide at least six position values, the optical encoders being coupled to the substrate table at different locations within a three dimensional coordinate system,
• wherein at least one position value is provided for each dimension of the three dimensional coordinate system,
• wherein the motion control system is configured to calculate the position of the substrate table within the three dimensional coordinate system from a subset of at least three of the six position values and to calculate an orientation of the substrate table with respect to the three dimensional coordinate system from another subset of at least three of the six position values,
• wherein at least one of the position detectors comprises a two-dimensional optical encoder comprising:
• a first grating mechanically coupled to the substrate table in order to follow a movement of the substrate table and a second grating, and
• two optical detectors, a first of the two optical detectors cooperating with the first grating in order to detect a movement of the first grating along a first dimension and a second of the two optical detectors cooperating with the second grating in order to detect a movement of the second grating along a second dimension, the first dimension being different from the second dimension.

A lithographic apparatus comprising:

• a substrate table configured to hold a substrate;
• an illuminator configured to condition a beam of radiation;
• a support structure configured to support a patterning device that imparts a desired pattern to the beam of radiation;
• a projection system configured to project the patterned beam onto a target portion of the substrate;
• and
• a motion control system configured to control a movement of the substrate table, the motion control system comprising a plurality of position detectors that detect a position of the substrate table, at least three of the position detectors each including a single or multi-dimensional optical encoder to provide at least six position values, the optical encoders being coupled to the substrate table at different locations within a three dimensional coordinate system,
• wherein at least one position value is provided for each dimension of the three dimensional coordinate system,
• wherein the motion control system is configured to calculate the position of the substrate table within the three dimensional coordinate system from a subset of at least three of the six position values and to calculate an orientation of the substrate table with respect to the three dimensional coordinate system from another subset of at least three of the six position values, and
• wherein at least one of the position detectors comprises a two-dimensional optical encoder, the two-dimensional optical encoder including two separate one-dimensional gratings arranged on a side of the substrate table.

A lithographic apparatus comprising:

• a substrate table configured to hold a substrate;
• an illuminator configured to condition a beam of radiation;
• a support structure configured to support a patterning device that imparts a desired pattern to the beam of radiation;
• a projection system configured to project the patterned beam onto a target portion of the substrate;
• and
• a motion control system configured to control a movement of the substrate table, the motion control system comprising a plurality of position detectors that detect a position of the substrate table, at least three of the position detectors each including a single or multi-dimensional optical encoder to provide at least six position values, the optical encoders being coupled to the substrate table at different locations within a three dimensional coordinate system,
• wherein at least one position value is provided for each dimension of the three dimensional coordinate system,
• wherein the motion control system is configured to calculate the position of the substrate table within the three dimensional coordinate system from a subset of at least three of the six position values and to calculate an orientation of the substrate table with respect to the three dimensional coordinate system from another subset of at least three of the six position values,
• wherein at least one of the position detectors comprises a two-dimensional optical encoder, the two-dimensional optical encoder including a two-dimensional grating arranged on a side of the substrate table, and
• wherein at least two of the optical encoders are adapted to operate with a common set of gratings.