Review of essential use of fluorochemicals in lithographic patterning and semiconductor processing
Christopher K. Ober, Florian Käfer, Jingyuan Deng
Abstract
We identify and describe categories of fluorochemicals used to produce advanced semiconductors within the lithographic patterning manufacturing processes. Topics discussed include the per- and polyfluoroalkyl substance (PFAS) materials used and their necessary attributes for successful semiconductor manufacturing, consisting of photoacid generators, fluorinated polyimides, poly(benzoxazole)s, antireflection coatings, topcoats, and embedded barrier layers, fluorinated surfactants, and materials for nanoimprint lithography. In particular, an explanation is given of the particular function that these PFAS materials contribute. It is noted that in almost all cases fluorine-free alternatives are very unlikely to provide the essential properties present in PFAS systems. Nonfluorinated alternative compounds are discussed where available. Finally, a summary table is provided listing the families of materials discussed, the critical purpose served, what the PFAS compound provides, and the prospects for alternatives.