Characterization and compensation of errors in multi-axis interferometry systems
First Claim
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1. A method, comprising:
- monitoring a position of a stage along a first measurement axis and a second measurement axis of a multi-axis interferometry system; and
determining a position of the stage with respect to another degree of freedom based on the monitored positions along the first and second axes and predetermined information about how the measurement axes deviate from being parallel to one another.
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Abstract
In general, in one aspect, the invention features a method that includes monitoring a position of a stage along a first measurement axis and a second measurement axis of a multi-axis interferometry system and determining a position of the stage with respect to another degree of freedom based on the monitored positions along the first and second axes and predetermined information about how the measurement axes deviate from being parallel to one another.
83 Citations
42 Claims
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1. A method, comprising:
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monitoring a position of a stage along a first measurement axis and a second measurement axis of a multi-axis interferometry system; and
determining a position of the stage with respect to another degree of freedom based on the monitored positions along the first and second axes and predetermined information about how the measurement axes deviate from being parallel to one another. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 34, 35, 36, 37, 38, 39, 42)
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24. A system, comprising:
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a multi-axis interferometry system configured to monitor a position of a stage along a first measurement axis and a second measurement axis; and
an electronic controller configured to determine a position of the stage with respect to another degree of freedom based on the monitored positions along the first and second axes and predetermined information about how the measurement axes deviate from being parallel to one another. - View Dependent Claims (25, 26, 27, 28, 31, 32, 33, 40, 41)
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29. A method for determining a position of a stage with respect to at least one degree of freedom, the method comprising:
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monitoring a location, x1, of the stage along a first measurement axis of a multi-axis interferometry system that produces an output beam comprising a phase related to an optical path difference between a path of a first beam and a path of a second beam, wherein the first beam contacts a measurement object associated with the stage at a first location and the first or second beam contacts the measurement object at a second location different from the first location;
monitoring a location, x2, of the stage along a second measurement axis of the multi-axis interferometry system; and
determining the position of the stage with respect to the degree of freedom based on x1, x2, and a correction term ψ
3,wherein ψ
3 accounts for contributions to the optical path difference caused by a deviation of the path of the first or second beam from a nominal beam path due to an imperfection of the measurement object at the first location and due to an imperfection of the measurement object at the second location. - View Dependent Claims (30)
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Specification