Etching method

Abstract

In a method for etching a first region, a sequence is performed one or more times. Each time of the sequence includes a first process of forming deposits containing fluorocarbon on a workpiece, and a second process of etching the first region by radicals of the fluorocarbon included in the deposits. After the sequence is performed one or more times, plasma of a second processing gas containing a fluorocarbon gas is generated, and the first region is further etched.

What is claimed is: 
     
         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.   
     
     
         2 . The method of  claim 1 , wherein in the process of generating the plasma of the second processing gas, the first region is continuously etched to a bottom of the recess. 
     
     
         3 . The method of  claim 1 , wherein each time of the sequence further includes a process of generating plasma of a third processing gas containing an oxygen-containing gas and an inert gas within the processing container that accommodates the workpiece. 
     
     
         4 . The method of  claim 3 , wherein in each time of the sequence, a process of generating the plasma of the third processing gas is performed between the process of generating the plasma of the first processing gas and the process of etching the first region by the radicals of the fluorocarbon, and
 each time of the sequence further includes a process of generating the plasma of the third processing gas within the processing container that accommodates the workpiece after the process of etching the first region by the radicals of the fluorocarbon is performed.