MARKER STRUCTURE FOR ALIGNMENT OR OVERLAY FOR CORRECTING PATTERN INDUCED DISPLACEMENT, MASK PATTERN FOR DEFINING THE MARKER STRUCTURE, AND LITHOGRAPHIC PROJECTION DEVICE USING THIS MASK PATTERN

摘要

PROBLEM TO BE SOLVED: To provide a mask pattern for imaging a marker structure for reducing the effects of lens aberration and limitations of light projection in a lithographic process.

SOLUTION: The mask pattern for imaging a marker structure on a substrate by lithographic projection is provided, wherein the marker structure is configured to determine an optical alignment or overlay in use, as shown in Fig.10, including constituent parts to define the marker structure. The constituent parts are segmented into a plurality of segmented elements EL;ML, each segmented element having substantially a size of a device feature. The mask pattern includes a segment shape for each segmented element EL;ML, wherein the mask pattern corresponding to the marker structure includes at least one assist feature EL_sub located at a critical part of the segment shape for counteracting optical aberrations or optical limitations generated in the lithographic projection at the critical part, and the at least one assist feature EL_sub has substantially a size below a resolution of the lithographic projection.

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