Plasma etch isotropy control
AssigneeTegal Corporation
InventorGianni O. Fior
Life of this patent
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Abstract
A tapered profile is obtained in oxide etched in a plasma glow discharge by switching the RF power between the side and lower electrodes in a tri-electrode reactor. The etch is isotropic while the RF power is applied to the side electrode and is anisotropic when the RF power is applied to the lower electrode.
Claims7
In a method for treating a semiconductor wafer subjected to a plasma glow discharge in a tri-electrode reactor having top, side, and lower electrodes, the improvement comprising:
- placing a wafer to be treated on said lower electrode;
- applying RF power only between the top and side electrodes of said reactor to cause an isotropic etch of said wafer;
- and
- applying RF power between the top and lower electrodes of said reactor to cause an anisotropic etch of said wafer.
In a method for etching an oxide layer on a semiconductor wafer subjected to a plasma glow discharge in a tri-electrode reactor having top, side, and lower electrodes, the improvement comprising:
- applying RF power between the top and side electrodes of said reactor to cause an isotropic etch of said oxide layer;
- and
- applying RF power between the top and lower electrodes of said reactor to cause an anisotropic etch of said oxide layer.
In apparatus for etching an oxide layer on a semiconductor wafer in a plasma glow discharge sustained by RF power in a gas contained within a reactor chamber;
- wherein said reactor has two, parallel plate electrodes of which one is connected to RF ground;
- a third, sidewall electrode enclosing at least a portion of the region between the other two electrodes;
- wherein the improvement comprises:
- means for alternately connecting RF power to said second and third electrodes.
Dependencies are inferred from the claim text.