Lithographic apparatus, calibration method, device manufacturing method and computer program product
AssigneeASML Netherlands B.V.
InventorsJeffrey Godefridus Tempelaars, Gerardus Carolus Hofmans, Rene Oesterholt, Jan Hauschild, Hans Kattouw
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Abstract
Calibration of spot height offsets in a level sensor is performed on a resist-coated substrate to eliminate process dependencies of substrate position measurements obtained by the level sensor.
Claims23
A device manufacturing method using a lithographic apparatus having a level sensor system comprising a plurality of level sensor devices configured to measure a position of a surface of a substrate at respective points thereon, the method comprising:
- obtaining at least one calibration value for the level sensor system, the at least one calibration value compensating for a difference in measured values among said plurality of level sensor devices, the at least one calibration value corresponding to a property of the substrate;
- measuring the position of the surface of a substrate using the plurality of level sensor devices based on the at least one calibration value;
- and
- exposing the substrate based on the measured position of its surface.
A calibration method in a lithographic apparatus having a level sensor system comprising a plurality of level sensor devices configured to measure a position of a surface of at least one substrate at respective points thereon, the method comprising:
- measuring a position, in a predetermined direction, of a plurality of points on the surface of the at least one substrate using each of said level sensor devices, wherein the at least one substrate has thereon a modified surface layer having a predetermined property.
A lithographic apparatus having a level sensor system comprising a plurality of level sensor devices configured to measure the position of the surface of a substrate at respective points thereon, the level sensor system including a model to relate actual measurements of the level sensor devices to position values and a calibration unit configured to apply a calibration value to the model, the calibration value dependent on a property of a surface layer of a substrate being measured.
A computer program product comprising program code to control a lithographic apparatus having a level sensor system comprising a plurality of level sensor devices configured to measure a position of a surface of a substrate at respective points thereon, to perform a device manufacturing method comprising:
- obtaining at least one calibration value for the level sensor system, the at least one calibration value compensating for a difference in measured values among said plurality of level sensor devices and corresponding to a property of the substrate;
- measuring the position of the surface of a substrate using the level sensor devices based on the at least one calibration value;
- and
- exposing the substrate based on the measured position of its surface.
Dependencies are inferred from the claim text.