Evidence of direct SiO{sub 2} etching by fluorocarbon molecules under ion bombardment

Journal Article · Sat Jan 01 04:00:00 EST 2005 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.1829400· OSTI ID:20664964

Takada, N; Toyoda, H; Murakami, I; Sugai, H ^[1]

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1. Department of Electrical Engineering and Computer Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

In a beam apparatus, influence of fluorocarbon gas (C{sub 5}F{sub 8}, C{sub 4}F{sub 8}, and CF{sub 4} molecules) flux onto SiO{sub 2} etching reaction is investigated in comparison to a case of CF{sub 2} radical flux. Fluorocarbon molecules or CF{sub 2} radicals are incident onto SiO{sub 2} surface with Ar{sup +} beam of energy 100-900 eV. Atomic composition of SiO{sub 2} surface under the ion and molecule incidence is measured by in situ x-ray photoelectron spectroscopy. Fluorocarbon/Ar{sup +} co-incidence enhances the SiO{sub 2} etching compared with pure Ar{sup +} incidence, suggesting the etching effect of fluorocarbon molecules under Ar{sup +} bombardment. In the case of C{sub 5}F{sub 8}/Ar{sup +} co-incidence, formation of fluorocarbon layer is observed as the case of CF{sub 2}/Ar{sup +} co-incidence. Etching yields of SiO{sub 2} by C{sub 5}F{sub 8}/Ar{sup +} and CF{sub 2}/Ar{sup +} co-incidences are measured for different Ar{sup +} incident energies and fluorocarbon/Ar{sup +} flux ratios. The etching yield increases monotonically with the Ar{sup +} incident energy, and reaches the value of 2.4 at 900 eV in case of C{sub 5}F{sub 8}, which is about 1.5 times as high as in the CF{sub 2} case. In the case of C{sub 5}F{sub 8} and CF{sub 2}, a phenomenon like etch stop, with formation of a thick fluorocarbon layer, is observed for larger fluorocarbon flux, with the threshold of the fluorocarbon/Ar{sup +} flux, ratio between 2.5 and 25. These results suggest a significant contribution of direct SiO{sub 2} etching by fluorocarbon molecules in practical etching reactors, especially in case of the C{sub 5}F{sub 8} molecule.

• OSTI ID: 20664964
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 1 Vol. 97; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ARGON IONS
CARBON FLUORIDES
CARBON TETRAFLUORIDE
ETCHING
EV RANGE 100-1000
ION BEAMS
MOLECULES
RADICALS
SILICON OXIDES
SPUTTERING
X-RAY PHOTOELECTRON SPECTROSCOPY