Plasma etching method and plasma etching apparatus

Abstract

In processing a magnetic film composed for example of Fe, Co or Ni formed on a substrate and a nonvolatile metal containing the same in a vacuum reactor using a plasma generating gas for generating plasma and a gas containing C and O, a power applied to an antenna for generating plasma is time-modulated, wherein the feeding of gas containing C and O to the vacuum reactor is synchronized with the time-modulated antenna power so that the supply of gas containing C and O to the vacuum reactor is suppressed when the antenna power is high and the gas containing C and O is fed to the vacuum reactor when the antenna power is low.

What is claimed is: 
     
         1 . A plasma etching method for plasma etching a magnetic film containing at least one element selected from the group consisting of Fe, Co and Ni in a processing chamber using a gas containing C element and O element,
 the method comprising:   etching the magnetic film by a time-modulated plasma; and   supplying a plasma generating gas, that is different from the gas containing C element and O element, to the processing chamber during a period with high amplitude of a time-modulated antenna power,   wherein a period with low amplitude of the time-modulated antenna power includes a first period, a second period, and a third period,   the first period is a period in which an electron temperature relaxes, and also is a period in which the gas containing C element and O element is not supplied to the processing chamber,   the second period is a period in which the gas containing C element and O element is supplied to the processing chamber, and   the third period is a period in which the gas containing C element and O element is not supplied to the processing chamber.   
     
     
         2 . The plasma etching method according to  claim 1 , wherein the plasma generating gas is further fed to the processing chamber during the second period. 
     
     
         3 . The plasma etching method according to  claim 1 , wherein the amount of gas containing C element and O element fed during the second period is varied with time. 
     
     
         4 . The plasma etching method according to  claim 1 , wherein a rare gas or a mixed gas containing the same is used as the plasma generating gas. 
     
     
         5 . The plasma etching method according to  claim 4 , wherein said rare gas is selected from the group consisting of He, Ar and Xe. 
     
     
         6 . The plasma etching method according to  claim 1 , wherein CO, CH 3 OH, C 2 H 5 OH, C 3 H 7 OH or CO 2  is used as the gas containing C element and O element. 
     
     
         7 . The plasma etching method according to  claim 1 , wherein the low amplitude of time-modulated antenna power is 1/10 or smaller of the high amplitude of time-modulated antenna power. 
     
     
         8 . The plasma etching method according to  claim 1 , wherein the first period is equal to or greater than 1 μs, and the third period is equal to or greater than 1 ms and is equal to or smaller than 50 ms. 
     
     
         9 . The plasma etching method according to  claim 1 , wherein H 2  gas or NH 3  gas is further supplied to the processing chamber during the second period.