Studies of plasma surface interactions during short time plasma etching of 193 and 248nm photoresist materials

As the device dimensions scale to 100nm, the use of photoresist materials is suitable for lithographic patterning at 193nm. The molecular structure of 193nm photoresist materials is significantly different from that of 248nm photoresist materials [H. Ito, IBM J. Res. Deu. 45, 683 (2001), T. Kajita et al., Proc. SPIE 4345, 712 (2001)], which leads to a number of undesirable consequences, including pronounced surface and line edge roughness during plasma etching [H. Ito, IBM J. Res. Deu. 41, 69 (1997), [E. Reichmanis et al., J. Vac. Sci. Technol. B 15, 2528 (1997), [L. Ling et al., ibid. 22, 2594 (2004)]. In this article, we present an investigation of the mechanisms for the surface/line edge roughening of photoresist materials during plasma etching using C4F8∕90%Ar discharges. We emphasized in our study short exposure times (the first few seconds) of the photoresist materials and structures to the plasma, a time regime that has not been well studied. Rapid modifications were observed for both 193 and 248nm...