Scatterometry overlay metrology targets and methods
AssigneeKLA-Tencor Corporation
InventorNuriel Amir
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Abstract
Scatterometry overlay (SCOL) targets as well as design, production and measurement methods thereof are provided. The SCOL targets have several periodic structures at different measurement directions which share some of their structural target elements or parts thereof. An array of common elements may have symmetry directions which are parallel to the measurement directions and thus enable compacting the targets or alternatively increasing the area use efficiency of the targets. Various configurations enable high flexibility in arranging the number of layers in the target and measurement directions, and carrying out respective overlay measurements among the layers.
Claims38
A scatterometry overlay (SCOL) target comprising at least two periodic structures at at least two measurement directions, each periodic structure comprising at least two types of periodically arranged target elements, wherein at least one type thereof is common to at least two of the at least two periodic structures.
A scatterometry overlay (SCOL) target comprising:
- at least two periodic structures at at least two measurement directions, each periodic structure comprising a plurality of periodically arranged target elements, and
- an array of pivoting elements, each pivoting element positioned between a pair of adjacent target elements with respect to each of the periodic structures.
A method comprising configuring pivoting elements, selected from a plurality of target elements in a SCOL target, to be common to at least two periodic structures having different measurement directions.
Dependencies are inferred from the claim text.