AVS 53rd International Symposium
    Thin Film Thursday Sessions
       Session TF-ThP

Paper TF-ThP14
Oxide-Nitride-Oxide (ONO) Deposition Mechanism and Modelling Study in a Batch Furnace for Sub-Micron Technology

Thursday, November 16, 2006, 5:30 pm, Room 3rd Floor Lobby

Session: Thin Film Poster Session
Presenter: E. Chiu, Aviza Technology, Inc.
Authors: E. Chiu, Aviza Technology, Inc.
A. Kolessov, Aviza Technology, Inc.
J. Bailey, Aviza Technology, Inc.
Correspondent: Click to Email
A highly uniform oxide-nitride-oxide (ONO) dielectric film deposition is required to achieve reliable flash memory device performance in the sub-micron manufacturing realm. A vertical furnace was used to investigate the effects of thin thermal oxide (<17Å), oxy-nitride and high temperature oxide (HTO) on film formation; uniform film control and low particle performance were achieved in the entire ONO film stack. In a batch reactor, various chamber and gas injection geometries were found to have moderate impact on within-wafer uniformity (WiW), while controlled temperature zone gradient significantly impacted wafer-to-wafer uniformity (WtW) across the load. Thermal oxide growth in oxygen and oxy-nitride deposition with DCS, NH@sub3@ and N@sub2@O provided excellent WiW and WtW uniformities in the optimized chamber configuration from these reaction rate controlled processes. From the HTO process experiments, high chamber pressure and low N@sub2@O/DCS gas ratio were found to be the contributing factors in improving WiW uniformity. A computer model and deposition reaction mechanism were developed to simulate flow, gas-phase and surface reactions to provide further understanding of the effects of HTO deposition with DCS and N@sub2@O. Results demonstrated that both the reaction and diffusion rates of gas species play an important role in determining the deposition efficiency. In the model, process temperature and reactant concentration mostly determined the WiW and WtW uniformities. As the simulation showed, the current chamber hardware could be further adjusted to improve the process performance. With optimized control of temperature zone gradient and reactant concentration, high quality films were deposited to meet and exceed the requirements for WiW and WtW ONO stack uniformities.