Wet and Dry Etching Characteristics of Electron Beam Deposited SiO and SiO2

Abstract

ABSTRACTWe have studied the thermal stability and etching characteristics of E-beam deposited SiO and SiO2. Dry etch rates were studied using SF6 and NF3 discharges in a Plasma Therm inductively coupled plasma system. Wet etch rates were assessed with buffered HF and HF/H2O solutions. SiO2 etched faster than SiO under all etch conditions. Dry etch rate of SiO2 was comparable with PECVD SiO2. Auger analysis indicated that SiO2 maintained excellent thermal stability after annealing to 700°C. The Si/O ratio of SiO in the film increased when annealed to 700°C. Ellipsometry also revealed greater refractive index variance across the sample for SiO, as compared to SiO2. However, thickness variation of both films was ≤ 2% across the wafer. Ellipsometry data also showed great thermal stability of SiO and SiO2. There was <4% change after 700°C annealing.