Aerial image characteristics of modified absorber model for extreme ultraviolet lithography (EUVL)

The extreme ultraviolet lithography (EUVL) is the most promising technique for manufacturing ultra-large-scale integration (ULSI) devices for the sub 50-nm technology node (Gwynn et al., 1998). The pattern image characteristics of EUVL mask has directly bearing on the lithographic performance and the accuracy of the resist imaging (Yan et al., 2000). For the oblique illumination on a EUVL mask in the exposure systems, the geometrical shadowing effect by the patterned absorber stack becomes critical issue in the pattern transfer process. Therefore, many research efforts have been focused on the absorber design to maximize the optical performance (Deng et al., 2003; Deng et al., 2004). In this work, the pattern printability of modified absorber models with various sidewall angles was quantitatively investigated by simulating aerial image intensity transferred through the system.