Patent ID: 7862735

Claim:
A method comprising: forming a photo resist film over a wafer substrate; performing a first patterning process over the photo resist film using a first mask, wherein the first mask is partially covered by a first metallic material leaving an first edge of the first mask open from the first metallic material; performing a second patterning process over the photo resist film using a second mask, wherein the second mask is partially covered by a second metallic material leaving an second edge of the second mask open from the second metallic material, wherein the first edge and the second edge overlap; and using the overlap of the first edge and the second edge to selectively expose the photo resist film to light, wherein at least one of the first metallic material and the second metal material comprises Cr, and wherein the second patterning process is performed after the first patterning process, and the second patterning process is performed before said using the overlap to selectively expose the photo resist film to light.