Lithographic apparatus and device manufacturing method utilizing a large area FPD chuck equipped with encoders an encoder scale calibration method
First Claim
1. A lithographic apparatus, comprising:
- an illumination system that conditions a radiation beam;
an array of individually controllable elements that modulate the radiation beam;
a substrate table that supports a substrate;
a projection system that projects the modulated radiation beam onto a target portion of the substrate, thereby applying a pattern to the target portion of the substrate, the pattern comprising a first line and a second line, the first line being offset from the second line;
a position encoder that determines a position of the substrate table, the position encoder comprising a position sensor and a scale, the scale comprising a plurality of lines intended to be straight and parallel to one another;
an imaging device that obtains an image of the first line and the second line; and
an image processing unit that measures separation between the first line and the second line in a plurality of locations thereby defining a plurality of separations and determines a non-uniformity of at least a part of the scale from the plurality of separations.
1 Assignment
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Accused Products
Abstract
A lithographic apparatus comprises an illumination system, an array of individually controllable elements, a substrate table, a projection system, a position encoder, an imaging device, and an image processing unit. The illumination system conditions a radiation beam. The array of individually controllable elements modulates the cross-section of the radiation beam. The substrate table supports a substrate. The projection system projects the modulated radiation beam onto a target portion of the substrate, thereby applying a pattern to the target portion of the substrate. The pattern comprises a first line and a second line. The first line is offset from the second line. The position encoder determines a position of the substrate table. The position encoder comprises a position sensor and a scale. The scale comprises a plurality of lines intended to be straight and parallel to one another. The imaging device obtains an image of the first line and the second line. The image processing unit measures the separation between the first line and the second line in a plurality of locations, and determines the non-uniformity of at least a part of the scale from the plurality of separations.
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Citations
28 Claims
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1. A lithographic apparatus, comprising:
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an illumination system that conditions a radiation beam;
an array of individually controllable elements that modulate the radiation beam;
a substrate table that supports a substrate;
a projection system that projects the modulated radiation beam onto a target portion of the substrate, thereby applying a pattern to the target portion of the substrate, the pattern comprising a first line and a second line, the first line being offset from the second line;
a position encoder that determines a position of the substrate table, the position encoder comprising a position sensor and a scale, the scale comprising a plurality of lines intended to be straight and parallel to one another;
an imaging device that obtains an image of the first line and the second line; and
an image processing unit that measures separation between the first line and the second line in a plurality of locations thereby defining a plurality of separations and determines a non-uniformity of at least a part of the scale from the plurality of separations. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A lithographic apparatus, comprising:
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an illumination system that conditions a radiation beam;
an array of individually controllable elements that modulate the radiation beam according to an intended pattern;
a substrate table that supports a substrate;
a projection system that projects the modulated radiation beam onto a target portion of the substrate;
a position encoder that determines a position of the substrate table, the position encoder comprising a position sensor and a scale, the scale comprising a plurality of lines intended to be equally spaced;
an imaging device that obtains an image of at least a part of a pattern exposed on the substrate; and
an image processing unit that compares the exposed pattern with at least a part of the intended pattern and determines a non-uniformity of at least a part of the scale from the comparison. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A method of determining a non-uniformity of lithographic apparatus, comprising:
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projecting a modulated radiation beam onto a target portion of a substrate, thereby applying a pattern to the target portion of a substrate, the pattern comprising a first line and a second line, the first line being offset from the second line;
determining a position of a substrate table supporting the substrate using a position encoder, the position encoder comprising a position sensor and a scale, the scale comprising a plurality of lines intended to be equally spaced;
using an imaging device to obtain an image of the first line and the second line;
measuring a separation between the first line and the second line in a plurality of locations; and
determining the non-uniformity of at least a part of the scale from the plurality of separations. - View Dependent Claims (16, 17, 18, 19, 20)
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21. A method of determining a non-uniformity of lithographic apparatus, comprising:
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projecting a modulated radiation beam onto a target portion of a substrate, thereby applying an exposed pattern to the target portion of substrate;
determining a position of a substrate table supporting the substrate using a position encoder, the position encoder comprising a position sensor and a scale, the scale comprising a plurality of lines intended to be equally spaced;
using an imaging device to obtain an image of at least part of the pattern;
comparing the pattern with a corresponding intended pattern; and
determining a non-uniformity of at least a part the of scale from the comparison. - View Dependent Claims (22, 23, 24, 25, 26, 27)
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28. A lithographic apparatus, comprising:
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an illumination source that conditions a radiation beam;
an array of individually controllable elements that modulate the radiation beam;
a substrate table that supports a substrate;
a projection system that projects the modulated radiation beam onto a target portion of the substrate;
a positioner that positions the substrate table; and
a position encoder arranged to determine a position of the substrate table.
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Specification