Chemistry of Materials

Characterization of a Novolac-Based Three-Component Deep-UV Resist

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High-sensitivity positive-tone deep-UV resists are described that utilize acid-catalyzed chemistry in novolac resin. These resists are composed of an acid-sensitive dissolution inhibitor, an acid photogenerator, and novolac resin. The lithographic functioning and processing of these resists are very similar to the familiar diazonaphthoquinone/novolac systems but with nearly a 100-fold increase in sensitivity. The resist sensitivity shows a surprising dependency on the choice of casting solvent, and this effect has been demonstrated to be related to the resist chemistry, which has been studied by using 2H NMR spectroscopy. The resist mechanism has been demonstrated to be primarily due to acid catalyzed thermolysis of the tert-butyl carbonate functional groups. The imaging characteristics of these resists is limited by the absorbance of the novolac resin, but submicron [TTPFeIV(C6H4CH3-p)]+ has been obtained. © 1990, American Chemical Society. All rights reserved.