Latin America and the Caribbean and China. Socioeconomic Debates on Trade and Investment and the case of CELAC

Abstract

Etching of thermal SiO2 using the HF/pyridine complex in supercritical CO2 (scCO2) was studied. Etch rate increases when HF concentration, processing temperature and fluid flow rates are increased. The decrease of the instantaneous etch rate as the processing time increases is attributed to the formation of etching residues on the film surface that act as a diffusion barrier. These residues are soluble in water and are identified as (Pyr)2SiF4 by FTIR analysis. For similar nominal HF concentrations, the SiO2 etch rate in anhydrous pyridine/scCO2 is much higher than in H2O. ?The Electrochemical Society.