METHOD OF CALIBRATING A LITHOGRAPHIC APPARATUS, DEVICE MANUFACTURING METHOD AND ASSOCIATED DATA PROCESSING APPARATUS AND COMPUTER PROGRAM PRODUCT

摘要

A lithography tool is calibrated using a calibration substrate having a set of first marks distributed across its surface in a known pattern. The tool is operated to apply a pattern comprising a plurality of second marks at various positions on the substrate, each second mark overlying one of the first marks and being subject to an overlay error dependent on an apparatus-specific deviation. The second marks are applied by multiple exposures while the substrate remains loaded in the tool. An operating parameter of the apparatus is varied between the exposures. An overlay error is measured and used to calculate parameter-specific, apparatus-specific calibration data based on knowledge of the parameter variation used for each exposure.

主权项

1. A method comprising:
(a) supporting a calibration substrate in a lithographic apparatus using a substrate support, the calibration substrate carrying a set of first marks; (b) operating a patterning system to apply a pattern comprising a set of second marks onto the calibration substrate, each second mark overlying a first mark; (c) obtaining an overlay measurement on the basis of the overlying first and second marks; and (d) using the overlay measurement to calculate calibration data to correct an apparatus-specific deviation of the lithographic apparatus, wherein operating the patterning system to apply the pattern comprising the set of second marks is repeated while the substrate remains supported by the substrate support so as to apply different sets of second marks while varying an operating parameter of the lithographic apparatus between applying the sets of second marks and including a shift between the different sets of second marks such that an overlay measurement of each set can be distinguished.