Overlay mark enhancement feature

Abstract

Methods and apparatuses for alignment are disclosed. An exemplary method includes providing a substrate having a device region and an alignment region; forming a first material layer over the substrate; forming a device feature and a dummy feature in the first material layer, wherein the device feature is formed in the device region and the dummy feature is formed in the alignment region; forming a second material layer over the first material layer; and forming an alignment feature in the second material layer, the alignment feature being disposed over the dummy feature in the alignment region. The device feature has a first dimension and the dummy feature has a second dimension, the second dimension being less than a resolution of an alignment mark detector.

Dependencies are inferred from the claim text.