Enhanced erosion resistance in semiconductor reactive ion etcher focus ring with large grain PVT SiC

Abstract

SiC focus rings are crucial for ensuring the uniformity of plasma reactive ion etching (RIE) in semiconductor processing. While chemical vapor deposition (CVD) is typically employed to fabricate large scale focus rings, these rings often show multiple pinhole surface defects following RIE processing. Here we introduced an approach to producing focus rings using a physical vapor transportation (PVT), harnessing a modified setup. Specific microscopic analysis demonstrated that SiC focus rings prepared through the PVT method significantly showed millimeter scale grain sizes with fewer grain boundaries, reducing be formation of pinhole defects. In contrast, focus rings produced by the CVD had microscale smaller grain size, resulting in abundant grain boundaries and numerous defects that were observed on these boundaries. This increase in grain size in the focus rings fabricated through the PVT provided three times higher erosion resistance (etch rate of 0.03 μm/min) compared to those prepared by CVD.