SiO2 + 6HF = H2 + SiF6 + 2H2O. As the etching rate of hydrofluoric acid on silicon dioxide is very high, it is difficult to control in the process, so in practice are used after dilution of hydrofluoric acid solution, or the addition of ammonium fluoride as a buffer mixture, to etch the silicon dioxide.

2 etch rate and the etch selectivity over ACL were increased. For a 300 W/500 W power ratio of 60-MHz HF power/ 2-MHz low-freqeuncy (LF) and a gas mixture of Ar (140 sccm) /C 4F 8 (30 sccm) /CHF 3 (25 sccm) /O 2 (5 sccm) while maintaining 20 mTorr, an anisotropic etch profile with an SiO 2 etch rate of 3350 ˚A/min and an etch selectivity of Plasma Etching - diyhpl surfaces is not adequate thus the removal rate of the Si is reduced. The etch rate of SiO2 should be 4 or 5 times the etch rate of the underlying Si. The chamber should be cleaned in an O2 plasma after each wafer is etched. US Patent 5935877 - Etch process for forming contacts over Titanium Silicide Chemical etch rates in HF solutions as a function of A comparative study of chemical etch rates in diluted HF or a mixture of HF, H2O, and HNO3 (P etch) was performed on conventional thermal silicon oxides (1050–1120 °C; O2 pressure ≊1.1 atm; one type with addition of 0.02% C2H3Cl3) and buried oxide layers. The latter were formed by single or multiple implanting n‐ and p‐type (100) Si maintained at ≊600 °C with 150–200‐keV O+

Buffered Oxide etchants have a long history in the IC industry as etchants for SiO2 films as well as for pre-diffusion and pre-metalization surface cleans. The ICL uses a 7:1 BOE as its wet oxide etch and diluted HF (unbuffered) for the surface cleans. Buffered HF has several advantages over unbuffered HF as an etchant, namely improved

A comparative study of chemical etch rates in diluted HF or a mixture of HF, H2O, and HNO3 (P etch) was performed on conventional thermal silicon oxides (1050–1120 °C; O2 pressure ≊1.1 atm; one type with addition of 0.02% C2H3Cl3) and buried oxide layers. The latter were formed by single or multiple implanting n‐ and p‐type (100) Si maintained at ≊600 °C with 150–200‐keV O+ Buffered Oxide Etch - INRF

The Etching Mechanisms of SiO in Hydrofluoric Acid

The etch-rate of silica ranges from 150 to 700 nm/min on a 150 mm wafer with the usual etch load (10–15%). Various glass etching processes with various etch mask materials are listed in Table 21.4. Table 21.4. Etch parameters and Etch Rates for Oxide and Mask Materials (nm/min) Etching with Hydrofluoric Acid - MicroChemicals Therefore, such additives allow a continued etching at a constant and high rate. This allows one to increase the etch rate at a reduced HF-concentration (= increased stability against re-sist peeling). Our Resists and Etchants We supply all mentioned resists also in 250 ml, 500 ml, and 1.000 ml units, and HF in a con-centration of 1%, 10%, and (PDF) Effect of HNO3 concentration on etch rate and Conductivity measurements can be used to monitor the etching rate of SiO2 in HF solutions very accurately when the etching rate is relatively slow (around 1 A/min). WET ETCHING OF SILICON DIOXIDE - microtechweb.com