Forming alignment mark and resulting mark
View Patent ↗Methods for forming an alignment mark and the resulting mark are disclosed. Embodiments may include forming a first shape having rotational symmetry; forming a second shape; and forming an alignment mark by combining the first shape and one or more of the second shape, wherein the alignment mark has rotational symmetry.
1. A method comprising:
forming a first shape having rotational symmetry;
forming a second shape;
forming an alignment mark by combining the first shape and one or more of the second shape; and
forming one or more concentric outlines within the first shape corresponding to a number of levels of exposure,
wherein the alignment mark has rotational symmetry.
2. The method according to claim 1 , comprising:
forming the alignment mark by combining the first shape with four of the second shape.
3. The method according to claim 2 , comprising:
placing an edge of each one of the four second shapes contiguous with a separate edge of the first shape to form the alignment mark.
4. The method according to claim 1 , wherein the first shape is a square and the second shape is a quadrilateral.
5. The method according to claim 1 , further comprising:
forming rotationally symmetric shapes along the one or more concentric outlines corresponding to features formed in the levels of exposure.
6. The method according to claim 1 , further comprising:
forming a cross-hatched grid of lines within the second shape corresponding to features formed in a number of levels of exposure.
7. The method according to claim 6 , further comprising:
forming rotationally symmetric shapes at intersections of the cross-hatched grid of lines.
8. An apparatus comprising:
a substrate; and
one or more rotationally symmetric alignment marks on the substrate,
wherein the one or more rotationally symmetric alignment marks comprise:
a first shape having rotational symmetry, and the first shape having one or more concentric outlines corresponding to a number of levels of exposure; and
at least one of a second shape.
9. The apparatus according to claim 8 , the one or more alignment marks comprise four of the second shape.
10. The apparatus according to claim 9 , the one or more alignment marks comprising:
an edge of each one of the four second shapes being contiguous with a separate edge of the first shape.
11. The apparatus according to claim 8 , wherein the first shape is a square and the second shape is a quadrilateral.
12. The apparatus according to claim 8 , the first shape further comprising:
rotationally symmetric shapes along the one or more concentric outlines corresponding to features formed in the levels of exposure.
13. The apparatus according to claim 8 , the second shape further comprising:
a cross-hatched grid of lines corresponding to features formed in a number of levels of exposure.
14. The apparatus according to claim 13 , the second shape further comprising:
rotationally symmetric shapes at intersections of the cross-hatched grid of lines.
15. A method comprising:
forming a first shape having 90-degree rotational symmetry;
forming at least one of a second shape, with an edge of each of the at least one second shape being contiguous with a separate edge of the first shape, forming an alignment mark;
forming one or more concentric outlines within the first shape corresponding to a number of levels of exposure; and
forming 90-degree rotationally symmetric shapes along the one or more concentric outlines corresponding to features formed in the levels of exposure,
wherein the alignment mark has 90-degree rotational symmetry.
16. The method according to claim 15 , further comprising:
forming a cross-hatched grid of lines within the second shape corresponding to features formed in a number of levels of exposure; and
forming rotationally symmetric shapes at intersections of the cross-hatched grid of lines.
17. The method according to claim 15 , wherein the first shape is a square and the second shape is a quadrilateral.