Plasma etching method

Abstract

In a plasma etching method of performing a plasma etching on an amorphous carbon layer of a substrate to be processed by using an inorganic film as a mask, the substrate being mounted in a processing chamber, the plasma etching on the amorphous carbon layer is performed by using O 2 gas as a processing gas and the O 2 gas to flow in the processing chamber such that a residence time of the O 2 gas becomes 0.37 msec or less. The amorphous carbon layer is used as an etching mask of an etching target film formed on the substrate. The plasma etching is performed by using the O 2 gas only.

What is claimed is: 
     
         1 . A plasma etching method of performing a plasma etching on an amorphous carbon layer of a substrate to be processed by using an inorganic film as a mask, being mounted in a processing chamber, the method comprising:
 performing the plasma etching on the amorphous carbon layer by using O 2  gas as a processing gas and allowing the O 2  gas to flow in the processing chamber such that a residence time of the O 2  gas becomes 0.37 msec or less.   
     
     
         2 . The method of  claim 1 , wherein the amorphous carbon layer is used as an etching mask of an etching target film formed on the substrate. 
     
     
         3 . The method of  claim 1 , wherein the plasma etching is performed by using the O 2  gas only. 
     
     
         4 . The method of  claim 1 , wherein a diameter of a hole or a width of a groove formed by the plasma etching of the amorphous carbon is equal to or greater than 100 nm and an aspect ratio thereof is equal to or smaller than 7. 
     
     
         5 . The method of  claim 1 , wherein a variation value 3σ (σ indicates standard deviation) is equal to or smaller than 50, 3σ being calculated by measuring diameters or widths at a plurality of locations between a top and a bottom portion of a cross sectional shape of the hole or the groove formed by the plasma etching of the amorphous carbon layer. 
     
     
         6 . The method of  claim 1 , wherein a value calculated by dividing a standard deviation σ by an average Ave. is equal to or smaller than 0.1, the standard deviation σ and the average Ave. being calculated by measuring diameters or widths at a plurality of locations between a top and a bottom portion of a cross sectional shape of the hole or the groove formed by the plasma etching of the amorphous carbon layer. 
     
     
         7 . A computer-readable storage medium storing a computer-readable program for controlling a plasma etching apparatus to execute the plasma etching method of  claim 1 .