AVS 45th International Symposium
    Plasma Science and Technology Division Wednesday Sessions
       Session PS-WeA

Paper PS-WeA8
Mechansims in High Aspect Ratio Oxide Feature Etching using Inductively Coupled Fluorocarbon Plasmas

Wednesday, November 4, 1998, 4:20 pm, Room 318/319/320

Session: Plasma-Surface Interactions I
Presenter: M. Schaepkens, State University of New York, Albany
Authors: M. Schaepkens, State University of New York, Albany
G.S. Oehrlein, State University of New York, Albany
K.G. Donohoe, Micron Technology, Inc.
J.M. Cook, Lam Research Corporation
Correspondent: Click to Email
Mechanisms controlling SiO@sub 2@ etching in high aspect ratio features have been studied using an inductively coupled plasma (ICP) source fed with trifluoromethane (CHF@sub 3@) gas. The behavior of the transition from fluorocarbon deposition to SiO@sub 2@ etching with increasing self-bias voltage has been determined in features with aspect ratios ranging from 0.8 to 6. Both the fluorocarbon deposition rate on the feature bottom at 0 W bias and the SiO@sub 2@ etching rate at highly negative self-bias voltages decrease with increasing aspect ratio. The SiO@sub 2@ etch rate reduction can be explained by a differential charging mechanism, for which experimental evidence is provided. Surface chemistry results obtained in microstructures are compared with unpatterned surfaces, and their significance for the etching process is discussed.