Novolak: Difference between revisions
Content deleted Content added
←Created page with ''''Novolaks''' (sometimes: novolacs) are low molecular weight polymers derived from phenols and formaldehyde. They are related to Bakelite, whic...' |
picture |
||
| Line 1: | Line 1: | ||
[[File:NovolakCresol.png|thumb|300 px|Segment of novolak, illustrating the predominance of cresol subunits and presence of [[crosslinking]].]] |
|||
'''Novolaks''' (sometimes: novolacs) are low molecular weight [[polymer]]s derived from [[phenol]]s and [[formaldehyde]]. They are related to [[Bakelite]], which is a more highly crosslinked version. The term comes from Swedish "lak" for lacquer and novo for new, since these materials were envisioned to replace natural lacquers such as [[copal resin]]. |
'''Novolaks''' (sometimes: novolacs) are low molecular weight [[polymer]]s derived from [[phenol]]s and [[formaldehyde]]. They are related to [[Bakelite]], which is a more highly crosslinked version. The term comes from Swedish "lak" for lacquer and novo for new, since these materials were envisioned to replace natural lacquers such as [[copal|copal resin]]. |
||
Typically novolaks are prepared by the condensation of a mixture of p- and m-[[cresol]] with formaldehyde (as formalin). The reaction is catalyzed by acid. [[Oxalic acid]] is often used because it can be subsequently removed by thermal decomposition. Novolaks have a [[degree of polymerization]] of approximately 20-40. The branching density, determined by the processing conditions, m- vs p-cresol ratio, as well as CH2O/cresol ratio is typically around 15%.<ref>{{cite book|title=Diazonaphthoquinone-based Resists| chapter=Basic Chemistry of Novolaks|author= Ralph Dammel|year=1993|publisher=Int. Soc. Optical Engineering|isbn=9780819410191}}</ref> |
Typically novolaks are prepared by the condensation of a mixture of p- and m-[[cresol]] with formaldehyde (as formalin). The reaction is catalyzed by acid. [[Oxalic acid]] is often used because it can be subsequently removed by thermal decomposition. Novolaks have a [[degree of polymerization]] of approximately 20-40. The branching density, determined by the processing conditions, m- vs p-cresol ratio, as well as CH2O/cresol ratio is typically around 15%.<ref>{{cite book|title=Diazonaphthoquinone-based Resists| chapter=Basic Chemistry of Novolaks|author= Ralph Dammel|year=1993|publisher=Int. Soc. Optical Engineering|isbn=9780819410191}}</ref> |
||
Novolaks are especially important in microelectronics.<ref>{{Kirk-Othmer|title=Lithographic Resists |
Novolaks are especially important in microelectronics where they are used as photoresist materials.<ref>{{Kirk-Othmer|title=Lithographic Resists |
||
|authors=W. D. Hinsberg, G. M. Wallraff|year=2005|doi=10.1002/0471238961.1209200808091419.a01.pub2}}</ref><ref>[http://ntp-server.niehs.nih.gov/ntp/htdocs/Chem_Background/ExSumPdf/Photoresists_DNQcmpds2_508.pdf Chemical Information Review Document for Diazonaphthoquinone Derivatives Used in Photoresists], National Toxicology Program, January 2006</ref> |
|authors=W. D. Hinsberg, G. M. Wallraff|year=2005|doi=10.1002/0471238961.1209200808091419.a01.pub2}}</ref><ref>[http://ntp-server.niehs.nih.gov/ntp/htdocs/Chem_Background/ExSumPdf/Photoresists_DNQcmpds2_508.pdf Chemical Information Review Document for Diazonaphthoquinone Derivatives Used in Photoresists], National Toxicology Program, January 2006</ref> |
||
Revision as of 18:46, 27 January 2019
Novolaks (sometimes: novolacs) are low molecular weight polymers derived from phenols and formaldehyde. They are related to Bakelite, which is a more highly crosslinked version. The term comes from Swedish "lak" for lacquer and novo for new, since these materials were envisioned to replace natural lacquers such as copal resin.
Typically novolaks are prepared by the condensation of a mixture of p- and m-cresol with formaldehyde (as formalin). The reaction is catalyzed by acid. Oxalic acid is often used because it can be subsequently removed by thermal decomposition. Novolaks have a degree of polymerization of approximately 20-40. The branching density, determined by the processing conditions, m- vs p-cresol ratio, as well as CH2O/cresol ratio is typically around 15%.[1]
Novolaks are especially important in microelectronics where they are used as photoresist materials.[2][3]
References
- ^ Ralph Dammel (1993). "Basic Chemistry of Novolaks". Diazonaphthoquinone-based Resists. Int. Soc. Optical Engineering. ISBN 9780819410191.
- ^ "Lithographic Resists", Kirk-Othmer Encyclopedia of Chemical Technology, New York: John Wiley, 2005, doi:10.1002/0471238961.1209200808091419.a01.pub2, ISBN 9780471238966
{{citation}}: Unknown parameter|authors=ignored (help) - ^ Chemical Information Review Document for Diazonaphthoquinone Derivatives Used in Photoresists, National Toxicology Program, January 2006