Dry etching of thermal SiO 2 using SF 6-based plasma for VLSI fabrication

Abstract

The plasma etching of thermal SiO 2 using a combination of SF 6, CHF 3 and He was investigated and a process developed on a parallel-plate planar plasma reactor. The etching of SiO 2 in fluorocarbon plasmas containing CF 4, mixtures of CF 4 and O 2 and mixtures of CF 4 and H 2 have been widely investigated and yielded important data about many of the fundamental mechanisms that are operative in plasma processing. SF 6 is a gas which is frequently used for the plasma etching of tungsten silicide, polysilicon and PECVD silicon nitride. However, little is reported about its use for the plasma etching of thermal SiO 2 in integrated circuit fabrication. This paper reports essential evaluations to characterize the SiO 2 plasma etch process using SF 6 and its application in the etching and fabrication of a Schottky contact.