| 摘要 |
A semiconductor target for determining a relative shift between two or more successive layers of a substrate is provided. The target comprises a plurality of first structures formed in a first layer, and the first structures have a first center of symmetry (COS). The target further comprises a plurality of second structures formed in a second layer, and the second structures have second COS. The difference between the first COS and the second COS corresponds to an overlay error between the first and second layer and wherein the first and second structures have a 180° rotational symmetry, without having a 90° rotational symmetry, with respect to the first and second COS, respectively. |
| 主权项 |
1. A semiconductor target for determining a relative shift between two or more successive layers of a substrate, the target comprising:
a plurality of first structures formed in a first layer with a first center of symmetry (COS); and a plurality of second structures formed in a second layer with a second COS, wherein the first and second structures have a particular rotational symmetry, without having a second rotational symmetry, with respect to the first and second COS, respectively, wherein the first COS and the second COS correspond to an overlay error between the first and second structures, and wherein the first and second structures have a 180° rotational symmetry, without having a second different rotational symmetry, with respect to the first and second COS, respectively. |
