A release etch model for etching sacrificial oxides in aqueous HF solutions is presented. This model is an extension of work done by Monk et al. and Liu et al. The model is inherently one dimensional, but can be used to model the etching of complex three dimensional parts. Solutions and boundary conditions are presented for a number of geometries. Knowledge of release-etch kinetics is essential for designing manufacturing processes for large surface micromachined structures such as sealed diaphragms and cavities and flow channels
