Target for measuring a parameter of a lithographic process
Disclosed is target arrangement comprising a first target region having at least a first pitch and at least a second pitch a second target region having at least a third pitch, wherein a portion of the first target region having a second pitch overlaps with a portion of the second target region.
1. A target arrangement comprising:
left and right regions and a first target region in a middle of the left and right regions, the first target region comprising at least first and second portions comprising respective first and second pitches; and
a second target region comprising at least a third pitch;
wherein the second portion overlaps with a portion of the second target region.
2. The target arrangement of claim 1 , wherein the first pitch and the second pitch of the first target region are in perpendicular directions.
3. The target arrangement of claim 1 , wherein the second target region is configured for metrology measurements of overlay, focus, dose, physical parameters of lithographic devices present on a wafer, tilt, side wall angles and/or critical dimensions.
4. The target arrangement of claim 1 , wherein the first target region is suitable for alignment metrology.
5. The target arrangement of claim 1 , wherein the second target region has a plurality of regions each comprising different pitches.
6. The target arrangement of claim 5 , wherein the second target region comprises overlapping regions.
7. The target arrangement of claim 6 , wherein the overlapping regions have different pitches.
8. The target arrangement of claim 6 , wherein the overlapping regions have a same pitch.
9. The target arrangement of claim 1 , wherein pitch variation is described by a continuous function.
10. The target arrangement of claim 1 , wherein:
the left, right, and first target regions are on a first grating,
the second target region is on a second grating, and
the first and second gratings are spaced apart from and overlapping each other.
11. The target arrangement of claim 10 , wherein the first and second gratings are on first and second layers of a substrate or wafer.