In plasma etching, radicals absorb and react on the wafer to form volatile products, which desorb and are pumped away by a vacuum system. The surface chemistry can be strongly modified by energetic ion bombardment. Ions bombard the wafer preferentially in the vertical direction, and in fact, plasma etching is the only commercially viable technology for anisotropic removal of material for delineating sub-half micron features.

Using FLUENT in conjunction with PLASMATOR, from Kinema Research and Software, we can successfully simulate both inductive and capacitively coupled discharges, and solve for dielectric/metal etching, and reactor cleaning. PLASMATOR utilizes a comprehensive chemistry set to characterize electron density, electron energy and electric potential. FLUENT uses this information to solve for ions, and neutral density distribution and to predict deposition/etch rates.

A

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Etch rate of oxide on wafer (A) and pedestal at 5 mtorr in a GEC cell (B).