Mechanism of reducing line edge roughness in ArF photoresist by using C F3 i plasma

Eiichi Soda, Seiichi Kondo, Shuichi Saito, Koji Koyama, Butsurin Jinnai, Seiji Samukawa

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


The roughening mechanism of ArF photoresist during etching was investigated to find out why C F3 I gas reduces the line edge roughness (LER) in the photoresist pattern better than C F4 gas. Since the plasma of reactive ion etching (RIE) consists of ultraviolet (UV) photons, radicals, and ions, the authors used a UV lamp and a neutral beam source for evaluating the effect of different plasma compositions on the photoresist roughness. The roughness was found not to increase only by UV photons or F radicals, but increase under the C F4 RIE plasma which has both UV photons and F radicals. A C-F modified layer was generated on the resist surface because the UV damaged CO bonds reacted with F radicals and the resist surface became softer and shrank. Since C F3 I plasma has a lower UV intensity and fewer F radicals compared with C F4 plasma, the shrinkage on the sidewall of the photoresist was suppressed and resulted in a smaller LER when this plasma was used.

Original languageEnglish
Pages (from-to)2117-2123
Number of pages7
JournalJournal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
Issue number5
Publication statusPublished - 2009

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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