The reactions of a chemically amplified positive resist, CAMP6, which is composed of poly tert-butoxycarbonyl(t-BOC)-styrene copolymer as a base resin and 2,6-dinitrobenzyl tosylate as a photoacid generator, were analyzed. The resist system generates acid upon exposure, undergoes acid catalyzed t-BOC deprotection during post-exposure bake and selectively dissolves in an aqueous base developer to give positive tone images. The acid generation and t-BOC deprotection reactions were analyzed by FTIR spectrometer and modeled successfully. The dissolution rates were measured by a Perkin Elmer development rate monitor (DRM). A new and simple dissolution rate model is presented since the dissolution rate behavior of chemically amplified positive resists can not be explained by the conventional models that are designed primarily for novolac/dissolution inhibition systems. The new dissolution rate model expresses the resist dissolution as a product of inhibition effect by the t-BOC groups and dissolution enhancement effect by the acid. Furthermore this new model can also explain surface inhibition effect by considering acid loss (deactivation) due to airborne contaminant diffusion from the resist surface. Prolith/2 was modified to incorporate the model and profile simulations were carried out successfully.
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