Identifying electron-induced reactions of inorganic complexes to enable mechanism-based design of new EUV resists

Johnathon Johnson,1 Fnu Nikita,1 Alex Bottorff,1 Rhea Shree-Patel,1 D. Howard Fairbrother,2
Mohammed Abdel-Rahman,2 Patrick Eckhert2 and Lisa-McElwee White1,*

1Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200,United States
2Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States

Extreme ultraviolet lithography (EUVL) is regarded as the most promising top-down lithographic technology for nanopatterns with sub-10nm resolution. In EUVL, 13.5 nm light is reflected off a patterned photomask and focused onto a spin coated silicon wafer with a thin layer of highly light-sensitive material. Absorption of EUV radiation by the photoresist generates low-energy (< 100 eV) secondary electrons which initiate chemical and physical transformations. Inorganic complexes have shown promise as the next generation of resists due to their enhanced EUV absorption compared to traditional polymer resists. We are synthesizing and evaluating a new class of inorganic resists based on polynuclear iodide complexes. The high sensitivity anticipated for these resists is a consequence of an extremely high EUV optical and electron density that results from a transition metal core which contains two bridging and two terminal iodide ligands. Insights from these complexes will provide the framework to identify the structure-reactivity relationships and design rules needed to synthesize organometallic complexes to serve as the next generation of EUVL resists.