Numeric analysis of the role of liquid phase ultraviolet photochemistry in 193 nm immersion lithography

A quantitative evaluation of the photochemistry taking place in the water fluid layer during lithographic immersion exposure with 193 nm radiation is described. This analysis uses a detailed kinetic model based on available literature mechanistic data and constructed with in-house simulation tools. Product yields from the intrinsic photochemistry of pure, degassed water, the effects of trace quantities of dissolved oxygen and organics on these photochemical reactions, and the potential impact of reactive photoproducts on a photoresist film in contact with the fluid are estimated. © 2005 American Vacuum Society.