Tailoring of novolac resins for photoresist applications using a two-step synthesis procedure

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.

Section: Introductionmentioning

confidence: 99%

“…The reaction time was found to be sufficient to consume almost all (95%) the formalin solution. 8 The second cresolic precursor (designated as "II" in Table I) was then added to the first cresolic monomer in a 1 : 1 ratio. The mixture was diluted with hydrochloric acid (1 : 1) in an ice bath and the pH was lowered to 4 -4.5.…”

Section: Introductionmentioning

confidence: 99%

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

Roy¹,

Pk²,

Raghunathan³

et al. 2003

“…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.…”

Section: Methodsmentioning

confidence: 99%

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

Sharma¹,

Raghunathan²,

Eswaran³

2008

A cardanol/m-cresol-based copolymer was esterified using di-tert-butyl dicarbonate (t-BOC), which makes it a suitable candidate as a possible e-beam resists. This work reports a full characterization of the product using the techniques of FTIR and UV-Visible spectroscopy, one dimensional 1 H NMR, 13 C NMR, DEPT-135. Two dimensional NMR experiments such as, COSY, HSQC, and HMBC have been employed for exhaustive probing of the microstructural details of this derivatized copolymer.

“…5 In the first step, p-cresol was mixed with formaldehyde and a base (NaOH) at room temperature and kept for 48 h. In the second step, the bishydroxymethylated p-cresol was allowed to react with twice the amount of m-cresol at an elevated temperature (140 -150°C) for 1 h in the presence of acidic catalysts. The polymer was then subjected to steam distillation and reprecipitated from ethyl acetate and hexane.…”

Section: Methodsmentioning

confidence: 99%

Quantitation of microstructure of novolac resins: Development of improved one‐ and two‐dimensional NMR methodologies

Roy

Raghunathan³

et al. 2003

ABSTRACT:The elucidation of the exact microstructure of polymers is always a challenging task. The range of molecular weights and uncontrolled polymerization leading to branching necessitates the development of better analytical methodologies. An improved methodology is presented for quantitatively estimating the microstructure of novolac resins and the percent incorporation of different monomers therein. An analysis is used that is based on the fully relaxed 1 H-NMR spectrum in combination with the results of twodimensional heteronuclear single quantum correlation, double quantum filtered correlation spectroscopy, and total correlation spectroscopy.