Determination of swing curve “shifts” as a function of illumination conditions: Impact on the CD uniformity

The use of a wide range of optical illumination settings may generate significant shifts in the photoresist (PR) swing curves. For technologies where critical dimension controls of few nanometers are required, the impact of these shifts on the critical dimension uniformity must be taken into account. In this paper, we have reproduced and quantified the shift of different swing curves (dose-to-clear and critical dimension) with a 248 nm positive PR. The impact of such shift on critical dimension uniformity has been determined on Deep UV Scanner.