High performance resist for EUV lithography

As the semiconductor industry moves to the 32 nm node, it becomes apparent that new lithography technology will be needed. One possibility for fabricating this feature size is extreme ultraviolet (EUV) technology. With the advent of EUV, new high performance resist materials will need to be developed. This study looks at the use of a poly[4-hydroxystyrene-co-2-(4-methoxybutyl)-2-adamantyl methacrylate] system as a possible candidate material for extreme ultraviolet lithography (EUVL). This material was synthesized and evaluated as an EUV chemically amplified resist. This resist system showed reasonable sensitivity and contrast compared to conventional PMMA resist. This resist system exhibits both negative and positive tone behavior at high and low dose, respectively. A negative pattern of 35 nm L/S (70 nm pitch) was printed using the transmission-grating EUV Interference Lithography (EUV-IL) tool [J.K. Chen, F.H. Ko, H.L. Chen, F.C. Chang, Jpn. J. Appl. Phys. 42 (2003) 3838]. A positive pattern of 50 nm (pitch 180 nm) was achieved using the EUVL tool at Sandia National Laboratory [Synchrotron Radiation Center website www.src.wisc.edu & Center for Nanotechnology website www.nanotech.wisc.edu]. Resist patterns were characterized in detail using scanning electron microscopy and atomic force microscopy. Both showed similar characteristics of the pattern lines.