The dry etching of TEOS oxide for poly-Si cantilevers in supercritical CO2

Dry etching of p-tetraethylorthosilicate (TEOS) with HF/H2O in supercritical carbon dioxide (scCO2) was studied. The etch rate of TEOS increased with HF concentration and reaction temperature, while the concentration of H2O and processing pressure were found to have little effect on the etch rate. Finally, poly-Si cantilevers with high aspect ratios (1:150) were released using this technique without stiction and residue on the surface.