Abstract
As the developments of semiconductor process technology continue to improve, process variations affect the circuit performance significantly. The problem of lens aberrations in lithography system cannot be neglected, and especially today’s lithography systems use high NA to push the technology node to 90nm or smaller one. It means that light travels the large portion of lens, so lens aberration effect is more significant [1]. Systematic Variations in optical lithography have many sources, such as mask error, flare and lens aberration, and the lens aberrations effect become more and more important among them in recent years. In this thesis, we introduce various systematic variations in optical lithography and focus on the phenomenon of lens aberrations effect. We use the lithography simulator, Athena, to simulate the results that lens aberrations affect the different test structures and then extract the CD contour maps. We model these systematic variations by the statistic multiple regression and use these models to estimate the path delay. We propose a framework to estimate the critical path delay of circuit affected by lens aberrations and observe the impact of lens aberration on circuit performance.