Post-lithography characterization of ArF resists for 45 nm node implant layers and beyond

Resolution and accuracy needs for the most advanced nodes, as well as fab capacities management are requirements that encourage the use of ArF resists for post-gate implant levels. In this paper, we investigate several key integration criteria that an ArF resist needs to fulfill to be used for implant applications. Outgassing level is followed during the first seconds of the implantation step and is systematically found under the chamber pressure limit. As well, stopping power efficiency is evaluated. SIMS analysis and simulation tests with SRIM software are performed to define the minimum resist thickness that prevents ions to penetrate the layers underneath. Data indicate that both experimental and simulation tests are in good agreement and that at low energies the stopping layer thickness is found to be in the order or lower than 80 nm. Finally, the impact of implantation step on patterned wafers is carried out. Features of interest are dense and isolated lines with a nominal CD of 130 nm. We control the CD and profile with a standard CD SEM and a CD AFM in order to get access to additional information such as height of the feature, top rounding and the CD through height. Results underline that our patterned resist doesn't show significant degradation under our implant conditions.