Cashew nut shell liquid-based tailor-made novolac resins: Polymer morphology quantitation by 1-D and 2-D NMR techniques and performance evaluation

The application of cashew nut shell liquid (CNSL) and CNSL-based polymers in the burgeoning microelectronics industry is rare. High ortho alternating and semialternating tailor-made novolac copolymers based on CNSL and in-cresol and/or p-cresol and have been made and successfully used as photoresists for microlithography. The microstructure of one of the representative m-cresol copolymer is exhaustively elucidated based on 1-D and 2-D NMR techniques. Incorporation of different monomers in the resin backbone has been quantitatively estimated based on an improved NMR methodology. The lithographic performance of photoresists using novolac resins based on cardanol (fractionated CNSL) and diazonaphthoquinone ester was also evaluated. (C) 2003 Wiley Periodicals, Inc.