Overlay target
An overlay target that includes a plurality of working zones and a plurality of line segments. The line segments in each of the working zones have a plurality of widths and are parallel to each other.
1. An overlay target, comprising:
a plurality of working zones; and a plurality of line segments in each of the working zones, wherein in each of the working zones, the plurality of line segments are parallel to each other in an arrangement direction, have a plurality of widths in the arrangement direction, and have the same length in an extension direction perpendicular to the arrangement direction; wherein the overlay target has a center, and the working zones surround the center; and wherein the line segments comprise a first line segment and a second line segment, the second line segment is farther from the center than the first line segment, the second line segment has a second width, and the second width is greater than a first width of the first line segment.
2. The overlay target according to claim 1 , wherein a configuration of the working zones is rotationally symmetric.
3. The overlay target according to claim 1 , wherein the line segments comprise a third line segment, and the second line segment is sandwiched between the first line segment and the third line segment.
4. The overlay target according to claim 3 , wherein the third line segment has a third width greater than the second width.
5. The overlay target according to claim 4 , wherein a ratio of the third width to the first width is greater than or equal to 2.
6. The overlay target according to claim 1 , wherein, the working zones comprise a first working zone and a second working zone laterally adjacent to the first working zone, and the line segments in the first working zone are perpendicular to the line segments in the second working zone.
7. The overlay target according to claim 6 , wherein the working zones further comprise a third working zone and a fourth working zone laterally adjacent to each other, wherein the third working zone is longitudinally adjacent to the second working zone, the fourth working zone is longitudinally adjacent to the first working zone, and the line segments in the third working zone are perpendicular to the line segments in the fourth working zone.
8. The overlay target according to claim 7 , wherein the line segments in the first working zone are parallel to the line segments in the third working zone, and the line segments in the second working zone are parallel to the line segments in the fourth working zone.
9. The overlay target according to claim 7 , wherein the line segments in the first working zone have a plurality of end portions adjacent to one side of an innermost line segment of the line segments in the fourth working zone.
10. An overlay target, comprising:
a plurality of working zones; and
a plurality of line segments in each of the working zones, wherein in each of the working zones, the plurality of line segments are parallel to each other in an arrangement direction, have a plurality of widths in the arrangement direction, have the same length in an extension direction perpendicular to the arrangement direction, and the greater a distance from the line segments to a center of the overlay target, the greater a width of the line segments.
11. The overlay target according to claim 10 , wherein a configuration of the working zones is rotationally symmetric.
12. The overlay target according to claim 10 , wherein the working zones comprise a first working zone and a second working zone adjacent to the first working zone, and the line segments in the first working zone are perpendicular to the line segments in the second working zone.
13. The overlay target according to claim 12 , wherein the working zones comprise a third working zone and a fourth working zone which is adjacent to the second working zone, the line segments in the first working zone are parallel to the line segments in the third working zone, and the line segments in the second working zone are parallel to the line segments in the fourth working zone.
14. The overlay target according to claim 13 , wherein the line segments in the first working zone and the line segments in the third working zone are center-symmetric, and the line segments in the second working zone and the line segments in the fourth working zone are center-symmetric.
15. The overlay target according to claim 10 , wherein the line segments in a same working zone of the working zones have a same length.
16. The overlay target according to claim 10 , wherein the line segments are second layers filling a plurality of grooves in a first layer.
17. The overlay target according to claim 16 , wherein the second layer comprises a metal layer.
18. The overlay target according to claim 16 , wherein the second layer is planarized by performing a chemical mechanical polishing process.