Overlay measurement structures and method of overlay errors
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorYen-Liang CHEN
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Abstract
An overlay error measurement structure includes a lower-layer pattern disposed over a substrate, and an upper-layer pattern disposed over the lower-layer pattern and at least partially overlapping with the lower-layer pattern. The lower-layer pattern includes a plurality of first sub-patterns extending in a first direction and being arranged in a second direction crossing the first direction. The upper-layer pattern includes a plurality of second sub-patterns extending in the first direction and being arranged in the second direction. At least one of a pattern pitch and a pattern width of at least one of at least a part of the first sub-patterns and at least a part of the second sub-patterns varies along the second direction.
Claims20
An overlay error measurement structure, comprising:
- a lower-layer pattern disposed over a substrate;
- and
- an upper-layer pattern disposed over the lower-layer pattern and at least partially overlapping with the lower-layer pattern, wherein:
- the lower-layer pattern includes a plurality of first sub-patterns extending in a first direction and being arranged in a second direction crossing the first direction,
- the upper-layer pattern includes a plurality of second sub-patterns extending in the first direction and being arranged in the second direction, and
- at least one of a pattern pitch and a pattern width of at least one of at least a part of the first sub-patterns and at least a part of the second sub-patterns varies along the second direction.
An overlay error measurement structure, comprising:
- a lower-layer pattern disposed over a substrate;
- and
- an upper-layer pattern disposed over the lower-layer pattern, wherein:
- the lower-layer pattern includes a first group of a plurality of first sub-patterns extending in a first direction and being arranged in a second direction crossing the first direction, and a second group of a plurality of first sub-patterns extending in the first direction and being arranged in the second direction,
- the upper-layer pattern includes a first group of a plurality of second sub-patterns extending in the first direction and being arranged in the second direction, and a second group of a plurality of second sub-patterns extending in the first direction and being arranged in the second direction,
- the first group of the upper-layer pattern at least partially overlaps the first group of the lower-layer pattern and is shifted in the second direction by an amount of D+OV with respect to the first group of the lower-layer pattern,
- the second group of the upper-layer pattern at least partially overlaps the second group of the lower-layer pattern and is shifted in the second direction by an amount of −D+OV with respect to the second group of the lower-layer pattern,
- D is a predetermined design value and OV is an overlay error between the lower-layer and the upper-layer along the second direction, and
- at least one of a pattern pitch and a pattern width of at least one of at least a part of the first sub-patterns and at least a part of the second sub-patterns varies along the second direction.
A method of measuring an overlay error,
- forming an upper-layer overlay measurement pattern over a lower-layer overlay measurement pattern;
- applying measurement light to the upper-layer and lower-layer overlay measurement patterns;
- obtaining diffraction patterns from the upper-layer and lower-layer overlay measurement patterns;
- analyzing a diffraction pattern image of the diffraction patterns with respect to a plurality of regions within the diffraction pattern image;
- and
- obtaining the overlay error between the upper-layer overlay measurement pattern and the lower-layer overlay measurement pattern by using a plurality analyzed results,
- wherein a pattern configuration of the upper-layer overlay measurement pattern is different from a pattern configuration of the lower-layer overlay measurement pattern, other than a relative location of the upper-layer overlay measurement pattern and the lower-layer overlay measurement pattern.
Dependencies are inferred from the claim text.