AVS 47th International Symposium
    Plasma Science and Technology Tuesday Sessions
       Session PS-TuM

Paper PS-TuM8
Surface Reaction Model for Etch-rate Calculations in SiO@sub 2@ Selective Etching

Tuesday, October 3, 2000, 10:40 am, Room 311

Session: Modeling of Plasma Processes
Presenter: S. Kobayashi, Association of Super-Advanced Electronics Technologies (ASET), Japan
Authors: S. Kobayashi, Association of Super-Advanced Electronics Technologies (ASET), Japan
T. Tatsumi, Association of Super-Advanced Electronics Technologies (ASET), Japan
M. Matsui, Association of Super-Advanced Electronics Technologies (ASET), Japan
K.K. Kawashima, Association of Super-Advanced Electronics Technologies (ASET), Japan
M. Sekine, Association of Super-Advanced Electronics Technologies (ASET), Japan
Correspondent: Click to Email
A surface reaction model was constructed to predict Si and SiO@sub 2@ etch rates in fluorocarbon plasma. This model is based on experimental results, obtained in a dual-frequency (27/0.8 MHz) parallel-plate RIE system@footnote 1@ that is widely used in manufacturing processes. Although it is not based on a first-principal calculation, we carefully tried to keep physical meanings in the calculation. At the first, we chose input parameters, such as ion energy, ion flux, incident flux of CF@sub x@ species, and oxygen atom flux measured by various in-situ diagnostics such as IRLAS, QMS, and OES. Then, the reaction probability between fluorine and Si or SiO@sub 2@, and the energy loss by a C-F polymer layer were estimated from the experimental data. Based on this model, a simulation program was coded. The calculation starts on the clear Si or SiO@sub 2@ surface. Using the parameter set such as C-F species flux, ion flux and energy, the C-F polymer thickness and the etched amount were alternately calculated because each value depends on each other. Therefore, the calculation is iteratively continued until the variation of the C-F polymer thickness becomes small enough. We performed the calculation and obtained the selectivity when varying the C@sub 4@F@sub 8@ and oxygen flow rates individually. A highly selective etch process could be predicted using the model calculation and discussed the best condition for the etching process using a calculation instead of a conventional experimental analysis. @FootnoteText@ This work was supported by NEDO. @footnote 1@T.Tatsumi et al., J. Vac. Sci. Technol., A17 (1999) 1562.