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US 2011/0213584 A1Published application
Calibration of Lithographic Apparatus
AssigneeASML Netherlands B.V.
InventorsBoris MENCHTCHIKOV, Alexander PADIY
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Abstract
System parameters are checked through self-assessment of a production wafer without a reference or a monitor wafer. In particular, exposure errors and substrate table positioning errors can be corrected for.
Claims14
A method, comprising:
- detecting errors in system parameters of a lithographic apparatus, wherein the detecting errors comprises:
- performing a plurality of exposures on a substrate, each exposure being carried out on an exposure area on the substrate and forming one or more markers within the exposure area, wherein neighboring exposure areas share at least one overlapping region;
- and
- measuring the overlay between the markers formed from the neighboring exposures in the overlapping regions measuring the positions of the markers across the substrate;
- combining differences in the measured positions of the markers between exposures in the overlapping regions with the measured positions of the other markers to obtain absolute values of system parameter errors;
- and
- deriving calibration correction factors from the obtained system parameter errors.
4 more elements
A lithographic apparatus comprising;
- an illuminator configured to perforin a plurality of exposures on a substrate, each exposure being carried out on an exposure area on the substrate and forming one or more markers within the exposure area, wherein neighboring exposure areas share at least one overlapping region;
- a measurement device configured to measure the overlay between the markers formed from the neighboring exposures in the overlapping regions and to measure the positions of the markers across the substrate;
- and
- a computing device configured to combine the differences in the measured positions of the markers between exposures in the overlapping regions with the measured positions of the other markers to obtain absolute values of system parameter errors and to derive calibration correction factors from the obtained system parameter errors.
1 more element
Dependencies are inferred from the claim text.