Super-resolution optical measurement of nanoscale photoacid distribution in lithographic materials

Adam J. Berro, Andrew J. Berglund, Peter T. Carmichael, Jong Seung Kim, J. Alexander Liddle

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)


We demonstrate a method using photoactivation localization microscopy (PALM) in a soft-material system, with a rhodamine-lactam dye that is activated by both ultraviolet light and protonation, to reveal the nanoscale photoacid distribution in a model photoresist. Chemically amplified resists are the principal lithographic materials used in the semiconductor industry. The photoacid distribution generated upon exposure and its subsequent evolution during post-exposure bake is a major limiting factor in determining the resolution and lithographic quality of the final developed resist image. Our PALM data sets resolve the acid distribution in a latent image with subdiffraction limit accuracy. Our overall accuracy is currently limited by residual mechanical drift.

Original languageEnglish
Pages (from-to)9496-9502
Number of pages7
JournalACS nano
Issue number11
Publication statusPublished - 2012 Nov 27


  • chemically amplified resist
  • lithography
  • photoacid
  • single-molecule fluorescence
  • super-resolution microscopy

ASJC Scopus subject areas

  • General Materials Science
  • General Engineering
  • General Physics and Astronomy


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