Feasibility of 250 nm gate patterning using i-line with OPC

Abstract

Excellent resolution and latitudes can be obtained with the commercially available advanced i-line resists. However, printing close to the resolution limit results in severe optical proximity effects (OPE). These effects limit the intra-die CD control severely. In order to manufacture devices with sub-0.35μm design rules, optical proximity correction (OPC) is needed. The goal of this paper is to illustrate the ultimate CD-control that can be obtained using an advanced i-line resist process and stepper in combination with OPC. Applying OPC results in clear improvements for 350, 300 and 275 nm features. CD-error over the full space/line ratio range is better controlled, resulting in larger overlapping exposure windows. For all the features, end-of-line shortening is significantly reduced applying OPC.