Gaseous process and apparatus for removing films from substrates

Abstract

A process for removing at least a portion of a film from a substrate, such as a wafer of silicon or other similar materials, the film on the substrate typically being an oxide film, maintaining the atmosphere embracing the substrate at near room temperature and at near normal atmospheric pressure, flowing dry inert diluent gas over the substrate, introducing a flow of reactive gas, preferably an anhydrous hydrogen halide gas, namely anhydrous hydrogen flouride gas, for typically 5 to 30 seconds over the substrate and film to cause the removal of portions of the film, flowing water vapor laden inert gas, preferably nitrogen, over the substrate and film from a time prior to commencing flow of the reactive gas until flow of the reactive gas is terminated. In the case of non-hygroscopic film on the substrate, the flow of water vapor continues during the flow of the reactive gas and is terminated shortly after the termination of the flow of reactive gas. In the case of hygroscopic film, the flow of water vapor is discontinued prior to the start of flow of the reactive gas. In carrying out the process, a process chamber is needed to confine the substrate and have a vent, which though restricted, continuously open to the atmosphere.