| 主权项 |
1. A method of selectively etching a first region formed of silicon oxide with respect to a second region formed of silicon nitride using a plasma processing on a workpiece,
wherein the workpiece includes the second region configured to define a recess, the first region formed to fill the recess and to cover the second region, and a mask formed on the first region, the mask providing an opening having a width wider than a width of the recess, above the recess, and wherein the method comprises: a sequence that is performed one or more times to etch the first region in a period including a time of exposing the second region, and a process of etching the first region by plasma of a second processing gas containing a fluorocarbon gas generated within a processing container after the sequence is performed one or more times, and wherein the sequence includes: a process of generating plasma of a first processing gas containing a fluorocarbon gas within the processing container that accommodates the workpiece in order to form deposits containing fluorocarbon on the workpiece, and a process of etching the first region by radicals of the fluorocarbon included in the deposits. |
