Multi-zone RF for wafer edge plasma profile tuning

Abstract

Internal meshes may causes a material discontinuity at the edge of a silicon wafer at a transition to the material of the pedestal. This causes a corresponding discontinuity in the RF power delivered to the plasma and consequently in the plasma profile. To solve this problem, one or more external meshes may be added around the periphery of the pedestal around the substrate. These external meshes may be individually coupled to variable impedances or variable RF sources. A controller may adjust the variable impedances and / or RF sources in order to tune the plasma profile around the edge of the substrate. This allows plasma-enhanced processes to provide a uniform plasma profile over the substrate, resulting in consistent and uniform process.

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