Optimization of 950K PMMA resists for Nano-application using Statistical Design Expert

Abstract

This paper discusses the application of a design of experiments (DOE) experimental method for analyzing the influence of four parameters (coating time, spinning speed, and softbake time and softbake temperature).involved in e-beam lithography process. Initially, the experimental methods applied to the lithography process are described. Main focus of this project is to optimize and to characterize the thickness of polymethyl-methacrylate (PMMA) with molecular weights of 950K. The thicknesses of PMMA resists are characterized and optimized to obtain ideal process settings for the best lithography performance. Parameters of lithography can be studied to determine the most significant factor that contributes to optimum performance. Results were evaluated by means of variance analysis (ANOVA) which assessed how the variation in the four different controllable parameters influenced PMMA thickness in lithography. Spinning speed is the main contributing factor to 950K PMMA thickness while coating time, softbake time and softbake temperature were found not important.