Effects of plasma molding on feature profile of silicon micro-electro-mechanical systems through flux ion velocity distributions in two-frequency capacitively coupled plasma in SF6/O2

Fukutaro Hamaoka, Takashi Yagisawa, Toshiaki Makabe

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

We numerically investigated large-scale Si etching of several hundreds of micrometers such as that used in micro-electromechanical systems (MEMS) fabrication. This was carried out in SF6 (83%)/O2 at 300mTorr in two-frequency capacitively coupled plasma using an extended VicAddress. We estimated the plasma molding's local characteristics including potential distribution and flux ion velocity distribution adjacent to an artificial microscale hole pattern. The sheath thickness is comparable to or even smaller than the size of the hole, and the sheath tends to wrap around the hole on a Si wafer. The distorted sheath field caused by the plasma molding directly affects the incident ion flux velocity distribution. The incident angle of SF5 + ions with a low energy strongly deviates from the normal surface at the hole's edge. The ion flux becomes radially nonuniform in the vicinity of the hole pattern, suppressing anisotropy of the etch profile. The feature profile of the Si hole indicates that the etching is enhanced particularly at the bottom corner and sidewall.

Original languageEnglish
Pages (from-to)3059-3065
Number of pages7
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Volume46
Issue number5 A
DOIs
Publication statusPublished - 2007 May 8

Fingerprint

Velocity distribution
Molding
velocity distribution
Fluxes
Plasmas
Silicon
Ions
silicon
profiles
sheaths
Etching
ions
Plasma sheaths
etching
MEMS
wrap
Anisotropy
Fabrication
microbalances
microelectromechanical systems

Keywords

  • 2f-CCP
  • MEMS fabrication
  • Modeling of etching
  • Negative ion plasma
  • SF /O plasma

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

Cite this

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title = "Effects of plasma molding on feature profile of silicon micro-electro-mechanical systems through flux ion velocity distributions in two-frequency capacitively coupled plasma in SF6/O2",
abstract = "We numerically investigated large-scale Si etching of several hundreds of micrometers such as that used in micro-electromechanical systems (MEMS) fabrication. This was carried out in SF6 (83{\%})/O2 at 300mTorr in two-frequency capacitively coupled plasma using an extended VicAddress. We estimated the plasma molding's local characteristics including potential distribution and flux ion velocity distribution adjacent to an artificial microscale hole pattern. The sheath thickness is comparable to or even smaller than the size of the hole, and the sheath tends to wrap around the hole on a Si wafer. The distorted sheath field caused by the plasma molding directly affects the incident ion flux velocity distribution. The incident angle of SF5 + ions with a low energy strongly deviates from the normal surface at the hole's edge. The ion flux becomes radially nonuniform in the vicinity of the hole pattern, suppressing anisotropy of the etch profile. The feature profile of the Si hole indicates that the etching is enhanced particularly at the bottom corner and sidewall.",
keywords = "2f-CCP, MEMS fabrication, Modeling of etching, Negative ion plasma, SF /O plasma",
author = "Fukutaro Hamaoka and Takashi Yagisawa and Toshiaki Makabe",
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AU - Yagisawa, Takashi

AU - Makabe, Toshiaki

PY - 2007/5/8

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N2 - We numerically investigated large-scale Si etching of several hundreds of micrometers such as that used in micro-electromechanical systems (MEMS) fabrication. This was carried out in SF6 (83%)/O2 at 300mTorr in two-frequency capacitively coupled plasma using an extended VicAddress. We estimated the plasma molding's local characteristics including potential distribution and flux ion velocity distribution adjacent to an artificial microscale hole pattern. The sheath thickness is comparable to or even smaller than the size of the hole, and the sheath tends to wrap around the hole on a Si wafer. The distorted sheath field caused by the plasma molding directly affects the incident ion flux velocity distribution. The incident angle of SF5 + ions with a low energy strongly deviates from the normal surface at the hole's edge. The ion flux becomes radially nonuniform in the vicinity of the hole pattern, suppressing anisotropy of the etch profile. The feature profile of the Si hole indicates that the etching is enhanced particularly at the bottom corner and sidewall.

AB - We numerically investigated large-scale Si etching of several hundreds of micrometers such as that used in micro-electromechanical systems (MEMS) fabrication. This was carried out in SF6 (83%)/O2 at 300mTorr in two-frequency capacitively coupled plasma using an extended VicAddress. We estimated the plasma molding's local characteristics including potential distribution and flux ion velocity distribution adjacent to an artificial microscale hole pattern. The sheath thickness is comparable to or even smaller than the size of the hole, and the sheath tends to wrap around the hole on a Si wafer. The distorted sheath field caused by the plasma molding directly affects the incident ion flux velocity distribution. The incident angle of SF5 + ions with a low energy strongly deviates from the normal surface at the hole's edge. The ion flux becomes radially nonuniform in the vicinity of the hole pattern, suppressing anisotropy of the etch profile. The feature profile of the Si hole indicates that the etching is enhanced particularly at the bottom corner and sidewall.

KW - 2f-CCP

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KW - Modeling of etching

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