| 摘要 |
A near substrate reactant homogenization apparatus reduces the excess reactive species in a region at or near the edge of a substrate surface to provide a uniform reactant concentration over the substrate, thereby improving etch rate uniformity over the substrate. The near substrate reactant homogenization apparatus has a substantially planar surface that is parallel to said substrate surface and that extends beyond the substrate edge, at or below the substrate surface. In a first preferred embodiment of the invention, the temperature of the gas absorber area is changed to promote recombination or condensation of excess reactive species at the substrate edge, where the excess species are removed. In another, equally preferred embodiment of the invention, the gas absorber area is formed of a porous material having a large surface area. Excess reactive species enter the porous structure and are subsequently recombined. In a third equally preferred embodiment of the invention, a gas curtain of a laminar inert or reactive gas may also be used along the substrate surface perimeter, either alone or in conjunction with the first or second embodiments of the invention, to form a diffusive barrier that suppresses the flux of excess reactive species at the substrate's edge.
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