ICP vs CCP in High Aspect Ratio Etching of SiO2 using Ar/C4F8/O2 Gas Mixtures

Inductively and capacitively coupled plasmas (ICP and CCP) are widely used in semiconductor device fabrication for a variety of etching and deposition processes. ICPs are typically used for metal and conductor etching while CCPs are typically used for dielectric etching. Decisions on these different applications of ICPs and CCPs were made largely on generations of devices whose characteristics are quite different from today's devices. In particular, high aspect ratio (HAR) devices (aspect ratios now exceeding 100) have more demanding requirements for anisotropy of incident ions and profile control, and less need for selectivity. Given these changing requirements, re-examination of the benefits and detriments of ICP vs. CCP for dielectric etching would provide needed guidance.