AVS 45th International Symposium
    Plasma Science and Technology Division Monday Sessions
       Session PS-MoP

Paper PS-MoP9
Investigations of Oxide Etching Using Validated Plasma Models

Monday, November 2, 1998, 5:30 pm, Room Hall A

Session: Plasma Science and Technology Poster Session
Presenter: J.E. Johannes, Sandia National Laboratories
Authors: J.E. Johannes, Sandia National Laboratories
T.J. Bartel, Sandia National Laboratories
M. Gallis, Sandia National Laboratories
E. Meeks, Sandia National Laboratories
Correspondent: Click to Email
Future technology, 0.25 micron and below, will require continued use of high density plasma (HDP) etch reactors to perform dielectric etch of fine-line, high aspect ratio features using fluorocarbon gases. Applying plasma models to better understand and design this process is difficult due to the lack of chemical information. By coupling fundemental chemical data, diagnostic data, and reactor scale models a validated plasma mechanism and model can be developed for predictive HDP simulations. A three step process will be defined for developing predictive HDP models. This study will focus specifically on a C@sub 2@F@sub 6@ plasma for oxide etch, although the strategy can be applied to other lasma systems. First, a preliminary mechanism is developed using existing cross sections and beam studies from the literature. A sensitivity analysis is then used to reduce the number of reactions and species in a preliminary C@sub 2@F@sub 6@ mechanism to generate a 'manangable' chemistry set for 2-D/3-D simulations. Phase two of this process is mechanism and model validation; this step is required to have confidence in the model. O-D and 2-D simulations are compared to available C2F6 plasma data, from both experimental and commercial reactors, to suggest improvements in the chemistry models and to validate the plasma models. A wide range of data comparisons used for mechanism development and validation will be presented for this study including: spatially resolved langmuir probe data, laser induced fluoresence (LIF) data, diode laser absorption data, Hiden probe data and oxide etch rates. A suite of four different codes will be used: 1.) Aurora, a well stirred reactor model, 2.) MPRES, a 2-D finite element plasma model , 3.) Icarus, a 2-D Direct Simulation Monte Carlo (DSMC) plasma code and 4.) Pegasus, a 3-D version of Icarus. The final step in the process is to apply the validated mechanism to investigate commercial processes. The validated mechanism will be applied in the DSMC codes to study the effects of etch rate and uniformity as a function of gas injection and flow rate in a commercial HDP. In addition, Icarus/Pegasus simulations will be performed to investigate 300 mm scale-up issues.