| 摘要 |
The invention is directed to an overlay mark in a first material layer in an overlay alignment region of a wafer and the first material layer is made from a first material. The overlay mark includes a plurality of mark regions and each of the mark regions comprises a plurality mark elements embedded in the first material layer. Each of the mark elements is made of a second material different from the first material of the first material layer and the mark elements evenly distribute in the mark region. |
