A new copper dry etching method has been discovered and studied. The process on an unique HCl plasma-copper reaction that forms a solution soluble copper chloride compound. The physical (e.g., morphology, profile, volume expansion, and anisotropy) and chemical (e.g., reaction mechanism) aspects of the solid-state copper chloride growth mechanism have been delineated. This new process is applicable to the copper interconnection technology for advanced microelectronic and optoelectronic devices and circuits.
