Surface interactions of SO{sub 2} and passivation chemistry during etching of Si and SiO{sub 2} in SF{sub 6}/O{sub 2} plasmas

Journal Article · Sat Jan 15 00:00:00 EST 2011 · Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films

DOI:https://doi.org/10.1116/1.3520126· OSTI ID:22051164

Stillahn, Joshua M; Jianming, Zhang; Fisher, Ellen R ^[1]

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1. Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872 (United States)

A variety of materials can be etched in SF{sub 6}/O{sub 2} plasmas. Here, the fate of SO{sub 2} at Si and SiO{sub 2} surfaces during etching in SF{sub 6}/O{sub 2} plasmas has been explored using the imaging of radicals interacting with surfaces method. The scattering of SO{sub 2} at Si and SiO{sub 2} surfaces was measured as a function of both the applied rf power and O{sub 2} addition to the plasma. For both surfaces, the surface scattering coefficient (S) of SO{sub 2} during etching is near unity and is largely unaffected by changing plasma parameters such as power and O{sub 2} addition. Notably the etch rate of Si increases monotonically with power, whereas the etch rate of SiO{sub 2} appears insensitive to changes in plasma conditions. As a result, the etch selectivity closely follows the trends of the Si etch rate. Etch rates are compared to other fluorine-containing plasma systems such as NF{sub 3}/O{sub 2} and C{sub 2}F{sub 6}/O{sub 2}. Using mass spectral data and optical emission spectra to characterize the gas phase species combined with compositional analysis from x-ray photoelectron spectroscopy data, the formation and roles of SO{sub 2} in Si and SiO{sub 2} etching are discussed and correlated with etch rate and other gas phase species such as F, O, and S{sub x}O{sub y}F{sub z}.

• OSTI ID: 22051164
• Journal Information: Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films, Vol. 29, Issue 1; Other Information: (c) 2011 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1553-1813
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CARBON FLUORIDES
EMISSION SPECTRA
ETCHING
FLUORINE
NITROGEN FLUORIDES
PASSIVATION
PLASMA
RADIOWAVE RADIATION
SCATTERING
SILICON OXIDES
SULFUR DIOXIDE
SULFUR FLUORIDES
SURFACES
X-RAY PHOTOELECTRON SPECTROSCOPY