Patent ID: 8664077

Claim:
A method for forming a self-aligned overlay mark, comprising: providing a first region and a second region disposed on a substrate and a main feature disposed between said first region and said second region and on said substrate, wherein said first region defines a first edge and said second region defines a second edge; forming a cut mask layer to respectively cover said first region and said second region, wherein said cut mask layer exclusively exposes said main feature; determining if said cut mask layer is self-aligned with at least one of said second edge and said first edge and creates a self-aligned overlay mark, wherein said main feature has a line/space array pattern and said space in the line/space array pattern is free of said edge of said cut mask layer; and performing a main feature etching step to transfer said main feature into said substrate when said cut mask layer is self-aligned with at least one of said second edge and said first edge.