During semiconductor processing in a process chamber, a substrate resting on a substrate support may undergo processes that deposit material on the substrate and to remove, or etch, portions of the material from the substrate, often in succession or in alternating processes. It is typically desirable to have uniform deposition and etching rates across the surface of the substrate. However, the inventors have noted that process non-uniformities often exist across the surface of the substrate and may be significant at the perimeter edge of the substrate. These non-uniformities at the perimeter are attributable to electric field termination effects and are sometimes referred to as edge effects.
During deposition, a process kit containing at least a deposition ring is sometimes provided to favorably influence the edge effects causing the non-uniformity at the substrate edge. The deposition ring generally is positioned around the substrate and rests on a portion of the substrate support. The deposition ring and other chamber components may also separate a processing volume of the chamber from a non-processing volume of the chamber, beneficially protecting some surfaces of the chamber from the processing environment.
Similarly, during etching, a ring is often provided around the substrate to, among other things, beneficially influence the removal of material from the substrate.
Deposition rings and etch rings, however, typically have different profiles and are positioned differently with respect to the substrate. In processes comprising a series of deposition/etching steps in rapid succession, process specific rings are not practical. Accordingly, the overall process suffers because a less than optimal ring configuration is used for each process.
Accordingly, the inventors have devised embodiments of an improved process kit for use in deposition and etching processes.