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US 10,761,420 B2Granted
Microlithographic mask, method for determining edge positions of the images of the structures of such a mask and system for carrying out such a method
AssigneeCarl Zeiss SMT GmbH
InventorDirk Hellweg
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Abstract
For the purposes of measuring structures of a microlithographic mask, a method for capturing absolute positions of structures on the mask and a method for determining structure-dependent and/or illumination-dependent contributions to the position of an image of the structures to be imaged, or of the edges defining this structure, are combined with one another. As a result of this, establishing an edge placement error that is relevant to the exposure of a wafer and, hence, a characterization of the mask can be substantially improved.
Claims20
A set, comprising:
- a plurality of different microlithographic masks, each microlithographic mask comprising:
- a metrology marker, comprising:
- an anchoring element configured so that its global position data on the microlithographic mask are establishable via an optical method using a measurement wavelength;
- and
- a test structure comprising structure elements imageable on a wafer with radiation at an imaging wavelength when the microlithographic mask is used,
- wherein for each microlithographic mask:
- a maximum distance of the structure elements of the test structure from the anchoring element is no more than one tenth of a side length of the microlithographic mask;
- the structure elements of the test structure are different from the structure elements of the test structure of all the other microlithographic masks;
- and
- the anchoring element is identical to the anchoring element of all the other microlithographic masks.
7 more elements
Dependencies are inferred from the claim text.