High Performance Resists Tailored for 248 nm Chemical Amplification of Resist Lines Technology

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Abstract
Different dry developable resist systems operating in positive bilayer (Si-CARL) and negative top surface imaging (Top-CARL) modes were investigated for application in 248 nm lithography. After exposure with the KrF excimer laser projection aligner (NA=0.37), development, aqueous silylation and oxygen reactive ion etching, 0.25 µm structures were obtained as the ultimate resolution of Si-CARL with a topresist containing diazoketone photoactive compounds. The process latitudes for 0.4 µm and 0.5 µm lines and spaces amount to 25% and 30% for exposure and to 3 µm and 3.2 µm for defocus, respectively. Comparable values were determined for an alternative Si-CARL system with a new acid catalysed topresist. The required doses for zero bias exposure are 65-70 mJ/cm2 (diazoketone) and 21 mJ/cm2 (acid catalysed). The Top-CARL resist also utilizes the acid catalysed deprotection chemistry for selective silylation of the exposed areas. The preliminary formulation presented well-shaped 0.35 µm structures at 10 mJ/cm2.