Exposure and development of thick polydimethylglutarimide films for MEMS applications using 254-nm irradiation

Ian Grant Foulds*, Robert W. Johnstone, See Ho Tsang, Manu Pallapa, Ash M. Parameswaran

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Polydimethylglutarimide (PMGI)-based resists are finding increasing use in microelectromechanical systems (MEMS) as both sacrificial and structural materials. PMGI-based resists are commercially available and were originally designed for use in bilayer lift-off applications. Literature on deep-UV exposure and development of PMGI films is limited to films less than 2.5 μm in thickness, and use only tetramethylammonium hydroxide (TMAH)-based developers. We investigate the exposure and development of PMGI films greater than 6 μm in thickness using the two main classes of developer for PMGI, TMAH, and tetraethylammonium hydroxide (TEAH)-based developers. At these thicknesses, a nonuniform dose through the film due to the optical absorption of the PMGI leads to large gradients in the dissolution properties. We report etch rates as a function of surface dose and development time. Additionally a model is developed to provide a basic predictor of development depth and other important data for fabrication process planning and development.

Original languageEnglish (US)
Article number023003
JournalJournal of Micro/Nanolithography, MEMS, and MOEMS
Volume7
Issue number2
DOIs
StatePublished - Jan 1 2008

Keywords

  • Absorption
  • Deep ultraviolet
  • Lithography
  • Microelectromechanical systems
  • Polymers
  • Thin films

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Mechanical Engineering
  • Electrical and Electronic Engineering

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