| abstract |
The purpose of the present invention is to provide a method for etching a silicon nitride region with a high selectivity.nAccording to this etching method, an object to be processed, which is provided with a silicon nitride region and a silicon-containing region having a composition different from that of the silicon nitride region, is contained in a process chamber and the silicon nitride region is selectively etched. In a first step, a deposit containing a hydrofluorocarbon is formed on the silicon nitride region and the silicon-containing region by producing a plasma of a processing gas containing a hydrofluorocarbon gas within the process chamber. In a second step, the silicon nitride region is etched by radicals of the hydrofluorocarbon contained in the deposit. The first step and the second step are alternately repeated. |