Correlation of UVIIHS resist chemistry to dissolution rate measurements

This article describes the correlation of UVIIHS resist chemistry to dissolution rate measurements as a function of resist processing conditions. The acid generation efficiency, alpha, for the UVIIHS photoacid generator is high, 0.027 cm(2)/mJ. The dissolution rate versus exposure curves show the excellent developer selectivity of UVIIHS, with n values >8 for all processes. The r(max) values for this resist are above 20 000 Angstrom/s, which is higher than any positive resist previously reported. The extent conversion for deprotection is directly related to the dissolution rate changes; similar to 30% deprotection correlates to the E(0) dose for all process conditions evaluated. At 30%-40% acid produced, all of the deprotection chemistry is essentially completed. The chemical contrast, as measured by extent conversion versus exposure dose, is strongly affected by the postexposure bake (PEB) temperature, with 140 degrees C FEB showing higher chemical and Lithographic contrast than the 130 degrees C PEB. Mack's dissolution model has been shown to work for these data sets. (C) 1996 American Vacuum Society.