Method for measuring photomasks
AssigneeCarl Zeiss SMT GmbH
InventorsDmitry Simakov, Thomas Thaler, Steffen Steinert, Dirk Beyer, Ute Buttgereit
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Abstract
The invention relates to a method for measuring a photomask for semiconductor lithography, including the following steps: recording an aerial image of at least one region of the photomask, defining at least one region of interest, ascertaining structure edges in at least one region of interest, providing desired structures to be produced by the photomask, adapting the ascertained structure edges to the desired structures, and displacing the adapted structure edges by means of the results of a separate registration measurement.
Claims20
A method for measuring a photomask for semiconductor lithography, comprising the following steps:
- recording an aerial image of at least one region of the photomask to generate a recorded aerial image of the at least one region of the photomask,
- defining at least one region of interest of the photomask,
- ascertaining structure edges in the at least one region of interest of the photomask based on the recorded aerial image to generate ascertained structure edges of the photomask,
- providing desired structures to be produced by the photomask,
- adapting the ascertained structure edges in the at least one region of interest of the photomask to the desired structures to be produced by the photomask to generate adapted structure edges of the photomask, in which the ascertained structure edges of the photomask are fitted to the desired structures to be produced by the photomask, and
- displacing the adapted structure edges of the photomask by use of the results of a separate registration measurement.
A method of generating structures on a wafer using a double exposure by a first photomask and a second photomask, the method comprising:
- recording an aerial image of at least one region of the first photomask to generate a recorded aerial image of the at least one region of the first photomask;
- defining at least one region of interest of the first photomask;
- ascertaining structure edges in the at least one region of interest of the first photomask based on the recorded aerial image to generate ascertained structure edges of the first photomask;
- providing desired structures to be produced by the first photomask;
- adapting the ascertained structure edges in the at least one region of interest of the first photomask to the desired structures to be produced by the first photomask to generate adapted structure edges of the first photomask, wherein the ascertained structure edges of the first photomask are fitted to the desired structures to be produced by the first photomask;
- displacing the adapted structure edges of the first photomask by use of the results of a separate registration measurement of the first photomask;
- recording a second aerial image of at least one region of a second photomask;
- defining at least one region of interest of the second photomask;
- ascertaining structure edges in the at least one region of interest of the second photomask to generate ascertained structure edges of the second photomask;
- providing desired structures to be produced by the second photomask;
- adapting the ascertained structure edges of the second photomask to the desired structures to be produced by the second photomask to generate adapted structure edges of the second photomask, wherein the ascertained structure edges of the second photomask are fitted to the desired structures to be produced by the second photomask;
- and
- displacing the adapted structure edges of the second photomask by use of the results of a separate registration measurement of the second photomask.
Dependencies are inferred from the claim text.