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

Abstract

ABSTRACT: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 m-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.

Derivatives of Cardanol through the Ene Reaction with Diethyl Azodicarboxylate

“…29,30 Note that in this reaction the olefins in cardanol are shifted in position and not destroyed. Thus, various modification reactions, such as epoxidation and polymerization, reported in the literature for cardanol, [3][4][5][6][7][8] can potentially be carried out on the cardanol-DEAD adduct.…”

“…Indeed a large number of cardanol derivatives and applications have been published in recent years, including phenolic resins from cardanol and formaldehyde, [3][4][5] epoxy curing resins, [6][7][8] flame retardants, 9,10 polyurethanes, [11][12][13][14] coatings, [15][16][17][18] biobased polymers, 19 and reactive diluents. 20,21 More derivatives have been given in a recent review.…”

Cashew nut shell liquid based t‐BOC protected alternating “high ortho” copolymer as a possible e‐beam resist: Characterization using multi‐dimensional NMR spectroscopy

“…15,16 In the first step, the first cresolic monomer (cardanol) was mixed with formaldehyde (37%) and sodium hydroxide in the ratio 1 : 2.2 : 1. The mixture was stirred mechanically at room temperature (258C) for 48 h. The second cresolic precursor (m-cresol) was then added to the first cresolic monomer in 1 : 1 ratio.…”

Photo‐induced cross‐linking mechanism in azide–novolac negative photoresists: molecular level investigation using NMR spectroscopy

“…The bishydroxymethylated cresol (BHMC) was separated, and the organic layer was washed thoroughly twice with water containing 1% oxalic acid. 17,18 In the second step, m-cresol was again mixed with liquid BHMC in a 1 : 1 ratio with the first phenolic monomer. A 1% molar equivalent of oxalic acid (with respect to the total cresolic components) was added.…”