Plasma Etching of Aluminum Alloys in BCL₃/CL₂ Plasmas

Aluminum etching in BCl₃/CL₂ plasmas is characterized by studying the etch rate of aluminum and native aluminum oxide films as functions of reactant flow rates and rf power in a parallel plate plasma etcher. Results indicate that the etch rate is primarlly dependent upon the Cl₂ concentration and is only slightly dependent upon the rf power used to sustain the discharge. Several additives are used to achieve the high resolution and anisotropic pattern required for aluminum alloys. Parametric studies support the roles of the additives have been made.