Effective Poly Gate CDU Control by Applying DoseMapper to 65nm and Sub-65nm Technology Nodes

Abstract

How effectively to control ACLV (across chip line variation) and AWLV (across wafer line variation) in 65nm and sub-65nm technology nodes becomes a very challenging task In this paper, our discussion will be focused on the most important part of CDU, which includes ACLV and AWLV. By using an ArF exposure tool, a DoseMapper application can successfully obtain the full wafer CDU of poly gate across wafer around 2.0nm (3σ, including ACLV and AWLV) in 65nm node. Moreover, with a state-of-the-art immersion ArF exposure tool the DoseMapper can even deliver the full wafer CDU around 1nm (3σ) in sub-65nm nodes. In addition, it has been proved that the DoseMapper application at post-etching is more effective than at post-litho stage because it also includes the systematic CD variation induced by etcher. However, the DoseMapper application at post-etch stage introduces a new challenge in litho CDU control. The CDU metric of 3σ or range is no longer meaningful at post-litho stage. A new methodology of CD control at post-litho will be presented in this paper.