Positive- and negative-tone water-processable photoresists: A progress report

Shintaro Yamada, David R. Medeiros, Kyle Patterson, Wei Lun K. Jen, Timo Rager, Qinghuang Lin, Carlos Lenci, Jeff D. Byers, Jennifer M. Havard, Dario Pasini, Jean M.J. Fréchet, C. Grant Willson

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

This paper presents the progress we have made toward the development of fully water processable, negative and positive tone I-line resist systems. The negative tone system is based on styrene copolymers bearing pendant ammonium sulfonate groups and vicinal diol functionalities. The salt provides the means of rendering the polymer water soluble. The diol undergoes an acid catalyzed pinacol rearrangement that results in a polarity switch within the exposed polymer film, i.e. a solubility differential. The styrene backbone was chosen to provide dry etch resistance. Positive tone imaging requires two solubility switches. The two solubility switches are based on the reaction between acidic hydroxyl groups in a matrix polymer and vinyl ethers that are introduced as a pendant group of the polymer or as a monomeric cross-linker, i.e. a bisvinyl ether. During the post application bake, the vinyl ether reacts with an acidic hydroxyl group in a thermally activated switch, forming a crosslinked, water insoluble network through acetal linkages. These acid labile crosslink sites are then cleaved by a photochemical switch through the generation of acid, thereby rendering the exposed areas water developable.

Original languageEnglish (US)
Pages (from-to)245-253
Number of pages9
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume3333
DOIs
StatePublished - 1998
Externally publishedYes

Keywords

  • Photoresist
  • Polarity switch
  • Vinyl ether
  • Water soluble

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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