Wafer edge characterization by successive radius measurements
First Claim
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1. A system, comprising:
- a polishing apparatus having one or more polishing stations for polishing of a substrate, the polishing stations operating with a plurality of polishing parameters;
an in-line monitoring system includinga substrate holder to hold the substrate at a location outside the polishing stations,a housing having an opening for receiving the substrate, andan eddy current sensor outside the polishing stations and near the opening to generate a signal based on a thickness of a layer of the substrate,wherein the sensor and the substrate holder are configured to undergo relative motion; and
a controller configured to cause the substrate holder to insert the substrate into the opening in the housing and to cause the sensor and substrate to undergo relative motion such that the sensor traverses a path including three or more angularly separated positions adjacent an edge of the substrate, the sensor configured to generate measurements at the three or more angularly separated positions, and the controller configured to receive the signal from the sensor and control at least one of the plurality of polishing parameters in response to the measurements.
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Abstract
Systems and methods for performing one or more measurements of a substrate at one or more radii along the substrate are described. Thickness measurements taken at various radii along the substrate can be averaged together to obtain an average value that reflects an overall substrate thickness. A more accurate measurement of the overall substrate thickness can be obtained by performing multiple measurements and averaging the measurements together. Using the average value, polishing can be adjusted to ensure that the substrate achieves a desired planarized thickness profile.
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Citations
33 Claims
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1. A system, comprising:
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a polishing apparatus having one or more polishing stations for polishing of a substrate, the polishing stations operating with a plurality of polishing parameters; an in-line monitoring system including a substrate holder to hold the substrate at a location outside the polishing stations, a housing having an opening for receiving the substrate, and an eddy current sensor outside the polishing stations and near the opening to generate a signal based on a thickness of a layer of the substrate, wherein the sensor and the substrate holder are configured to undergo relative motion; and a controller configured to cause the substrate holder to insert the substrate into the opening in the housing and to cause the sensor and substrate to undergo relative motion such that the sensor traverses a path including three or more angularly separated positions adjacent an edge of the substrate, the sensor configured to generate measurements at the three or more angularly separated positions, and the controller configured to receive the signal from the sensor and control at least one of the plurality of polishing parameters in response to the measurements. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A system, comprising:
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a polishing apparatus having one or more polishing stations for polishing of a substrate, the polishing stations operating with a plurality of polishing parameters; a monitoring system including a substrate holder to hold the substrate at a location away from the polishing stations, a sensor to generate a signal based on a thickness of a layer of the substrate, and an opening for receiving the substrate, wherein the sensor is positioned near the opening, wherein the sensor and the substrate holder are configured to undergo relative motion, and wherein the monitoring system is configured to detect a first edge of the substrate and a second edge of the substrate as the substrate holder scans the sensor across the substrate; and a controller configured to cause the sensor and substrate to undergo relative motion such that the sensor traverses a path, the sensor configured to generate measurements at three or more separated positions along the path, the controller configured to receive the signal from the sensor and control at least one of the plurality of polishing parameters in response to the measurements, and the controller is configured to cause the substrate holder to remove the substrate from the opening upon detection of the second substrate edge.
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21. A system, comprising:
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a polishing apparatus having one or more polishing stations for polishing of a substrate, the polishing stations operating with a plurality of polishing parameters; a monitoring system including a substrate holder to hold the substrate at a location outside the polishing stations, and a sensor outside the polishing stations to generate a signal based on a thickness of a layer of the substrate, wherein the sensor and the substrate holder are configured to undergo relative motion, and wherein the monitoring system is configured to detect a first edge of the substrate and a second edge of the substrate as the substrate holder scans the sensor across the substrate; and a controller configured to cause the sensor and substrate to undergo relative motion such that the sensor traverses a path, the sensor configured to generate measurements at three or more separated positions along the path, the controller configured to receive the signal from the sensor and control at least one of the plurality of polishing parameters in response to the measurements, and the controller configured to cause the substrate holder to rotate the substrate by an angle α
upon detection of the second substrate edge. - View Dependent Claims (22)
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23. A method comprising:
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holding a substrate on a substrate holder; inserting the substrate into an opening of a housing of an in-line monitoring system; scanning an eddy-current sensor positioned near the opening across the substrate in the in-line monitoring system, the scanning including causing the sensor to traverse a path including three or more angularly separated discrete points adjacent an edge of the substrate; generating a measurement signal associated with a thickness of the substrate at each of the three or more angularly separated discrete points from the sensor in the in-line monitoring system; and controlling a polishing parameter of a polishing apparatus based on the measurement signal. - View Dependent Claims (24, 25, 26, 27, 28, 29)
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30. A method comprising:
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scanning a sensor across a substrate in a monitoring system to position the sensor at three or more angularly separated discrete points adjacent an edge of the substrate; generating a measurement signal associated with a thickness of the substrate at each of the three or more angularly separated discrete points; detecting a first substrate edge and a second substrate edge of the substrate, the second substrate edge being farther away from the sensor than the first substrate edge when the first substrate edge is detected; rotating the substrate from a first radial segment to a second radial segment after detecting the second substrate edge; and controlling a polishing parameter of a polishing apparatus based on the measurement signal. - View Dependent Claims (31, 32, 33)
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Specification