Model for etch depth dependence on GaAs via hole diameter

Reactive ion etching of via holes for grounding of monolithic microwave integrated circuits has become the industry standard. It is well known that the via etch rate decreases as a function of decreasing via mask diameter as well as increasing etch depth. A model has been developed which relates the experimental etch rates in Cl 2 /BCl 3 /Ar plasmas to the ion and neutral fluxes incident on the wafer. This model provides a useful tool for designers and process engineers to predict etch depths and average etch rates as functions of via diameter and total etch time.