Status of high-index materials for generation-three 193nm immersion lithography

Abstract

Generation-three (Gen-3) immersion lithography can be an enabler for the 32nm half-pitch node. For Gen-3 lithography to be successful, however, there must be three major breakthroughs in materials development: high refractive index ("high-index") lenses, high-index immersion fluids, and high-index photo-resists. Currently a material for a high-index lens element, lutetium aluminum garnet (LuAG), has been identified. However, suitable materials choices remain elusive for both the Gen-3 fluid and resist. This paper reviews the successes and failures in the search for Gen-3 high-index materials. ©2007TAPJ.