Plasma processing method

Abstract

A plasma processing method for etching a sample includes generating a plasma in a treatment chamber having a stage on which the sample is placed, wherein the plasma is generated by use of electromagnetic waves, applying an rf bias to the stage with a frequency which enables reduction of ions having an intermediate energy, and on-off modulating the rf bias so that reaction products are deposited on the sample during the off period of the rf bias.

What is claimed is:  
     
         1 . A plasma processing method for etching a sample, comprising the steps of: 
 generating a plasma in a treatment chamber having a stage on which said sample is placed, the plasma being generated by use of electromagnetic waves;    applying an rf bias to the stage with a frequency which enables reduction of ions having an intermediate energy; and    on-off modulating the rf bias so that reaction products are deposited on the sample during the off period of the rf bias.    
     
     
         2 . A plasma processing method according to  claim 2 , wherein a duty ratio of the on-off modulating of the rf bias which is the ratio of the on periods in a certain cycle is set to 5 to 50%.