Modeling of sacrificial layer etching can be done by combining the diffusion rates of etchants in solution and the chemical reaction rate. Steady‐state diffusion is estimated for diffusion coefficients in water on the range of as observed from an independent experiment. Likewise, the chemical reaction rates (or initial etch rates) for each silicon dioxide/hydrofluoric acid system as a function of concentration are obtained from independent experiments. The etching kinetics of with HF are nonlinear. An analytical method is used with power law kinetic reaction rate expressions and Newton's method to linearize the problem. This allows the calculation of the surface concentration as a function of etching time. By equating the diffusive and reactive fluxes at the reaction surface, the surface HF concentration is calculated. Applying a forward Euler integrated etch rate relationship, the surface concentration can be used to plot the etch front location as a function of time.