Surface interactions of SO2 and passivation chemistry during etching of Si and SiO2 in SF6/O2 plasmas

Abstract

A variety of materials can be etched in SF6/O2 plasmas. Here, the fate of SO2 at Si and SiO2 surfaces during etching in SF6/O2 plasmas has been explored using the imaging of radicals interacting with surfaces method. The scattering of SO2 at Si and SiO2 surfaces was measured as a function of both the applied rf power and O2 addition to the plasma. For both surfaces, the surface scattering coefficient (S) of SO2 during etching is near unity and is largely unaffected by changing plasma parameters such as power and O2 addition. Notably the etch rate of Si increases monotonically with power, whereas the etch rate of SiO2 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 NF3/O2 and C2F6/O2. 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 SO2 in Si and SiO2 etching are discussed and correlated with etch rate and other gas phase species such as F, O, and SxOyFz.

Improvement of the Corrosion Resistance of Carbon Steel by Plasma Deposited Thin Films

“…www.intechopen.com The corrosion of Si-containing films upon fluorine-and oxygen-rich environments is a matter of interest in microelectronic (Chen et al, 2011, Stillahn et al, 2011 and aerospace (Huang et al, 2011) applications, respectively. To evaluate the chemical response of the films to such media, samples were exposed to reactive plasmas generated from SF 6 or O 2 .…”

Experimental investigation of SF6–O2 plasma for advancement of the anisotropic Si etch process

“…The etch rate also increases with an increase in RF DC bias [23] and later in 2011 discovered that etch rate increases with RF power [24].…”

Recent Researches in Corrosion Evaluation and Protection

“…Therefore, plasma power affects wettability of the films due to the chemical and topographical alterations, being the first one the most prominent in the definition of the trends. The corrosion of Si-containing films upon fluorine-and oxygen-rich environments is a matter of interest in microelectronic (Chen et al, 2011, Stillahn et al, 2011 and aerospace (Huang et al, 2011) applications, respectively. To evaluate the chemical response of the films to such media, samples were exposed to reactive plasmas generated from SF 6 or O 2 .…”