Proximity-controlled silicon carbide etching in inductively coupled plasma

Abstract

By controlling the proximity relative to plasma source, silicon carbide (SiC) has been etched in a C 2F 6 inductively coupled plasma. This was accomplished by adjusting the gap between the wafer substrate and the plasma source. Gap effects on SiC etching were extensively examined as a function of process factors as well as at particular two conditions, high source power (plasma density) and high bias power (ion bombardment). Decreasing the gap increased the etch rates for all conditions mainly due to the increased plasma density. The DC bias induced with the gap variation played a little role in affecting the etch rate. Gap effect was more enhanced as the wafer electrode was powered with relatively larger DC bias. Factor effects on the etch rates were quite different depending on the level of plasma density or ion bombardment. Decreasing the gap resulted in a microtrench at the base of the sidewall, which was little affected by the DC bias.