Study of symmetric microstructures for CMOS multilayer residual stress

Ying Jui Huang, Tien Li Chang, Hwai Pwu Chou

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

This study presents a fabrication-based approach to improve the curl-up effect in complementary metal oxide semiconductor (CMOS) multilayer large-area planar structures. Control of the residual stress of CMOS multilayer microstructures is necessary for development of microelectromechanical systems (MEMS) sensors such as accelerometers and micromirrors. In this work, 3D symmetric geometry can be used to overcome effectively the residual stresses in CMOS multilayer microstructures. To demonstrate this concept, a symmetric multilayer flat-plane is fabricated and release-etched using an isotropic plasma etching process. The isotropic etch characteristics and lateral undercut can be controlled using a chamber pressure of 0.47 ± 0.2 Torr. A flat-plane structure with an area of 500 μm × 500 μm is fabricated using multilayer materials, including four metal and three silicon dioxide layers. Based on this approach, the measured results show the residual stress effect can be minimized in CMOS multilayer microstructures, and furthermore the curl-up effect of flat-plane is less than 2 μm across the 500 μm × 500 μm area. Crown

Original languageEnglish
Pages (from-to)237-242
Number of pages6
JournalSensors and Actuators, A: Physical
Volume150
Issue number2
DOIs
Publication statusPublished - 2009 Mar 25

Keywords

  • CMOS-MEMS
  • Isotropic etching
  • Residual stresses
  • Symmetric multilayer flat-plane

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Electrical and Electronic Engineering

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