AVS 51st International Symposium
    Plasma Science and Technology Friday Sessions
       Session PS1+DI-FrM

Paper PS1+DI-FrM1
Inductively Coupled Plasma Etching of Poly-SiC in SF6 Chemistries

Friday, November 19, 2004, 8:20 am, Room 213A

Session: High K and Difficult Materials Etch
Presenter: S.H. Kuah, SAMCO International Inc.
Authors: S.H. Kuah, SAMCO International Inc.
P.C. Wood, SAMCO International Inc.
Correspondent: Click to Email
A study was made to find a low cost and robust etching solution for silicon carbide (SiC) using a commercially available inductively coupled plasma etching tool. Sulfur hexafluoride (SF6) was selected because of its high degree of F dissociation and non-hazardous nature. A parametric study of the etching characteristics of poly-SiC in inductively coupled plasma (ICP) SF6 chemistries was performed. Etch chemistry was found to greatly affect etch rate, selectivity, final surface cleanliness and smoothness. Etch rates as high as 5884 Å/min were achieved with high SiC/Cr selectivity (36) and clean, but relatively rough etched surfaces (134 Å RA) using a SF6/CF4/He gas mixture. It was found that He addition apparently increases the ionization of SF6 in the plasma and thus increases the SiC etch rate due to increases in the SF3+ and F radical concentrations@footnote 1,2@. The formation of pillar-like structures and side wall deposition was observed on the etched SiC surfaces under some conditions. These unwanted etch by-products exhibited a high concentration of Cr and Fluorine. However, an Ar plasma pre-clean of the the substrate, or high ICP and/or bias powers, and CF4 addition can reduce the pillars formation significantly. @FootnoteText@ @footnote 1@ J.D.Scofield, B.N.Ganguly, and P.Bletzinger, J.Vac.Sci.Technol. A 18, 2175 (2000).@footnote 2@ Z.A.Talib and M.Saporoschenko, Int. J. Mass Spectrom. Ion Processes 116, 1(1992).