Optically detectable alignment marks producing an enhanced signal-amplitude change from scanning of a detection light over the alignment mark, and associated alighment-detection methods

摘要

Alignment marks are disclosed that provide, when scanned by a detection-light beam, an enhanced signal-amplitude change. Such an alignment mark is formed on a mark substrate and is used for performing an alignment in a charged-particle-beam (CPB) microlithography system. The alignment mark includes at least one mark element defined as a corresponding height-difference characteristic in the mark substrate. The mark element includes more than two height-difference edges that would be encountered by a detection-light beam being scanned across the element. The height-difference edges of the element can be defined by multiple individual mark-element components that collectively provide the more than two height-difference edges of the mark element. Alternatively, for example, the element can include two height-difference edges at respective edges of the mark element and at least one height-difference edge situated between the two height-difference edges at respective edges of the mark element. The alignment mark is suitable for detection by an optical alignment-detection device of a CPB microlithography system.