AVS 46th International Symposium
    Plasma Science and Technology Division Thursday Sessions
       Session PS-ThM

Paper PS-ThM6
A Multi-dimensional Model for an Inductively Coupled Ar/C@sub 4@F@sub 8@ Discharge

Thursday, October 28, 1999, 10:00 am, Room 609

Session: Plasma-Surface Interactions II
Presenter: S. Rauf, Motorola Inc.
Authors: S. Rauf, Motorola Inc.
P.L.G. Ventzek, Motorola Inc.
V. Arunachalam, Motorola Inc.
D.G. Coronell, Motorola Inc.
Correspondent: Click to Email
Plasmas based on complex fluorocarbons such as C@sub 4@F@sub 8@ are the main workhorse for SiO@sub 2@ etching in the microelectronics manufacturing industry. To understand the etching mechanism and how important process parameters (e.g. etch rate, uniformity) are related to typical actuators (e.g. gas pressure, power), we have recently developed a 2-dimensional model for an inductively coupled Ar/C@sub 4@F@sub 8@ discharge. The model is based on the Hybrid Plasma Equipment Model, a comprehensive plasma equipment simulation tool developed at the University of Illinois. For this project, the plasma is treated as a fluid and rates for various electron impact processes are computed using a homogeneous Boltzmann equation solver. The gas phase chemical mechanism includes electron impact ionization, dissociation and attachment processes for C@sub 4@F@sub 8@ and its C@sub x@F@sub y@ progeny, ion-ion and ion-molecule chemistry. A reasonably detailed description of surface processes at the SiO@sub 2@ coated wafer is also included. The plasma reactor model is coupled to an external circuit model. The model was used to simulate Ar/C@sub 4@F@sub 8@ based plasmas in the inductively coupled Gaseous Electronics Conference reference cell. C@sub 4@F@sub 8@ concentrations were between 10-50%, gas pressure was varied between 10-30 mTorr and total inductive power deposition was 300-700 W. Results show that most of the incoming C@sub 4@F@sub 8@ dissociates quite rapidly near the inlet into CF@sub x@ (x = 1,2,3) radicals. Substantial amount of C@sub 2@F@sub 4@ is also present in the discharge. The plasma is moderately electronegative with F@super -@ being the major negative ion. Implications of control parameters on the plasma characteristics and etching kinetics will be discussed.