Method of cleaning plasma etching apparatus

Abstract

Method of cleaning a plasma etching apparatus capable of suppressing variation in line width among wafers in a single lot, and improving throughput in the cleaning process, includes steps of supplying a cleaning gas into a chamber of a plasma etching apparatus; igniting a plasma of the cleaning gas in the chamber; and allowing plasma cleaning to proceed in the chamber, by bringing the cleaning gas in plasma form into contact with a deposit adhered on the inner wall of the chamber so as to etch off the deposit, wherein in the step of plasma cleaning in the chamber, intensity of plasma emission ascribable to the deposit adhered on the inner wall of the chamber is detected in a time-dependent manner, and the plasma cleaning in the chamber is terminated based on changes in the intensity of the plasma emission.

1 . A method of cleaning a plasma etching apparatus comprising:
 supplying a cleaning gas into a chamber of a plasma etching apparatus;   igniting a plasma of the cleaning gas in the chamber;   allowing plasma cleaning to proceed in the chamber, by bringing the cleaning gas in a plasma form into contact with a deposit adhered on the inner wall of the chamber so as to etch off the deposit;   detecting an intensity of plasma emission ascribable to the deposit adhered on the inner wall in a time-dependent manner;   terminating the plasma cleaning in the chamber based on changes in the intensity of the plasma emission; and   after the terminating the plasma cleaning, introducing an inert gas into the chamber, detecting gas concentration of a predetermined compound in the chamber in a time-dependent manner, and terminating the introduction of the inert gas based on changes in the gas concentration.   
     
     
         2 . The method of cleaning a plasma etching apparatus according to  claim 1 ,
 wherein the terminating the introduction of the inert gas is terminating the introduction of the inert gas when the gas concentration falls down to a predetermined value or when a rate change in the gas concentration falls in a predetermined range.   
     
     
         3 . The method of cleaning a plasma etching apparatus as claimed in  claim 1 , wherein terminating the plasma cleaning in said chamber occurs when the intensity of said plasma emission falls down to a predetermined value or below, or rate of change in the intensity of said plasma emission falls in a predetermined range. 
     
     
         4 . The method of cleaning a plasma etching apparatus as claimed in  claim 1 , wherein said cleaning gas is a gas containing an oxidative gas. 
     
     
         5 . The method of cleaning a plasma etching apparatus as claimed in  claim 1 , wherein the intensity of said plasma emission is emission intensity of COx. 
     
     
         6 . The method of cleaning a plasma etching apparatus as claimed in  claim 1 , wherein the intensity of said plasma emission is such as observed at a wavelength in the plasma emission having a peak at around 520 nm. 
     
     
         7 . A manufacturing method for a semiconductor device comprising:
 cleaning the plasma etching apparatus according to  claim 1 ;   performing a dry etching to a semiconductor device in the plasma etching apparatus after the cleaning the plasma etching apparatus.