Exploratory approaches to the study of acid diffusion and acid loss from polymer films using absorption and fluorescence spectroscopy

摘要

Abstract: As the feature size in microlithography decreases inresponse to the demand for increasing miniaturization,problems related to acid diffusion and acid loss becomemore important. In an attempt to address these issues,we have examined various techniques based on absorptionand fluorescence spectroscopy. We have synthesized, ordeveloped for applications in this field a range oddyes where their absorption and fluorescence changedramatically as a result of acid-induced changes intheir prototropic forms. These dyes represent the basisfor an in situ method for quantifying acid in films.Approaches for monitoring acid movement into/out offilms have been developed and rate constants for acidloss from poly(vinylphenol) films of various acids atdifferent temperatures have been determined. In anapproach to measure acid diffusion, we make use of thefact that fluorescent patterns produced by contactprinting of polymer films containing a dye can bereadily resolved by fluorescence microscopy and thatdiffusion leads to deterioration of these images. Inyet another approach, we have used laser photolysistechniques with nanosecond-microsecond resolution togenerate acid photochemically and monitor on short timescales its arrival to dye-containing sites within thepolymer films. The advantages and disadvantages of eachtechnique will be discussed, as well as the role ofacid, polymer Tg and temperature on aciddiffusion/loss. !10