Patent ID: 7732340

Claim:
A method of etching a substrate, comprising: forming a film stack on said substrate, said film stack comprising a composite layer having an upper material layer, an intermediate sub-layer and a lower material layer, and a mask layer overlying said composite layer having a pattern formed therein; and transferring said pattern to said composite layer using one or more etching processes by: transferring said pattern to said upper material layer of said composite layer until said intermediate sub-layer is reached, adjusting at least one critical dimension (CD) of said pattern in said upper material layer, transferring the adjusted pattern in said upper material layer to said intermediate sub-layer, and transferring the adjusted pattern to said lower material layer of said composite layer, wherein said pattern comprises a rectangular pattern characterized by a first CD along a major axis of said pattern and second CD along a minor axis of said pattern, and wherein said adjusting comprises adjusting a ratio of said first CD to said second CD in said upper material layer of said composite layer such that said adjusted ratio in said upper material layer of said composite layer is substantially the same as an initial ratio of said first CD to said second CD in said mask layer.