US Patent 7833427 Electron beam etching device and method

Methods and devices for selective etching in a semiconductor process are shown. Chemical species generated in a reaction chamber provide both a selective etching function and concurrently form a protective coating on other regions. An electron beam provides activation to selective chemical species. In one example, reactive species are generated from a halogen and carbon containing gas source. Addition of other gasses to the system can provide functions such as controlling a chemistry in a protective layer during a processing operation.