Vacuum processing apparatus and vacuum processing method of sample

Abstract

Provided is a vacuum processing apparatus or processing method which, when films of a plurality of layers are etched into a predetermined shape, eliminates a deficiency in shape formed by sample processing, increases the aspect ratio of the processed shape, and provides a more precise shape. The vacuum processing apparatus of the present invention comprises a vacuum container the inside of which can be depressurized and a sample holder located inside of the vacuum container to place thereon a sample to be processed; is used for etching, into a predetermined shape, films of a plurality of layers laid over the sample surface with plasma formed using an electric field and a processing gas fed in a space above the sample holder inside of the vacuum container; and is equipped with a heat conducting gas feed means for feeding a heat conducting gas between a sample mounting surface and the backside of the sample, wherein the apparatus is equipped further with a heat-conducting-gas pressure control function for changing stepwise the pressure of the heat conducting gas fed between the sample mounting surface and the backside of the sample in accordance with the progress of the processing of the films of a plurality of layers of the sample.

1 . A vacuum processing apparatus comprising a vacuum container inside of which can be depressurized,—a sample holder located inside of the vacuum container to mount thereon a sample to be processed and a heat conducting gas feed unit for feeding a heat conducting gas between a sample mounting surface and the backside of the sample; for etching films of a plurality of layers laid over the sample surface into a predetermined shape with plasma generated using an electric field and a processing gas fed in a space above the sample holder inside of the vacuum container, wherein: 
 the apparatus further comprising a heat-conducting-gas pressure control unit for changing stepwise the pressure of the heat conducting gas fed between the sample mounting surface and the backside of the sample in accordance with the progress of the processing of the films of a plurality of layers of the sample.    
   
   
       2 . A vacuum processing apparatus according to  claim 1 , wherein the heat-conducting-gas pressure control unit further comprising with a unit of reducing the pressure stepwise when the processing reaches the interface between the films of a plurality of layers or vicinity of the interface.  
   
   
       3 . A vacuum processing apparatus according to  claim 1  or  2 , further comprising an introduction channel for feeding the heat conducting gas to the sample mounting surface, wherein: 
 the heat-conducting-gas pressure control unit further comprising a valve which is placed on an exhaust channel, communicated with the introduction channel and serving to discharge the heat conducting gas from the introduction channel, and whose opening degree can be controlled stepwise.    
   
   
       4 . A vacuum processing apparatus according to  claim 3 , wherein the heat-conducting-gas pressure control unit comprising a pair of a roughing line having, in a channel thereof, not an orifice but a valve and a fine tuning line having, in a channel thereof, a valve and an orifice.  
   
   
       5 . A vacuum processing apparatus comprising a vacuum container the inside of which can be depressurized, a sample holder which is located inside of the vacuum container and constitutes a substrate electrode on which a sample to be processed is mounted and a heat conducting gas feed unit for feeding a heat conducting gas between a sample mounting surface of the sample holder and the backside of the sample and a substrate bias power supply connected to the substrate electrode; said vacuum processing apparatus is used for etching, into a predetermined shape, of films constituting a plurality of layers mounted over the surface of the sample with plasma generated by an electric field and a processing gas fed to a space above the sample holder inside of the vacuum container; wherein: 
 the apparatus further comprising a heat-conducting-gas pressure control unit for changing stepwise the pressure of the heat conducting gas fed between the sample mounting surface and the backside of the sample in accordance with the progress of the processing of the films constituting a plurality of layers of the sample, and a substrate bias control unit for changing stepwise the output of the substrate bias power source in accordance with the progress of the processing of the films of a plurality of layers of the sample.    
   
   
       6 . A vacuum processing apparatus according to  claim 5 , wherein the heat-conducting-gas pressure control unit is equipped with a unit of reducing stepwise the pressure when the processing reaches the interface between the films of a plurality of layers or the vicinity of the interface and the substrate bias control unit of heightening the substrate bias stepwise.  
   
   
       7 . A vacuum processing method comprising the steps of: 
 mounting a sample to be processed on a sample mounting surface on a sample holder placed in a vacuum container whose inside can be depressurized;    feeding a processing gas and electric field to a space above the sample holder inside of the vacuum container to generate plasma; and    etching films of a plurality of layers laid over the surface of the sample into a predetermined shape, wherein:    a heat conducting gas is fed between the sample mounting surface and the backside of the sample, and at the same time,    the pressure of the heat conducting gas is changed stepwise in accordance with the progress of the processing of the films of a plurality of layers of the sample.    
   
   
       8 . A vacuum processing method according to  claim 7 , wherein the pressure is reduced stepwise when the processing reaches the vicinity of the interface between the films of a plurality of layers.  
   
   
       9 . A vacuum processing method according to  claim 7  or  8 , wherein the pressure of the heat conducting gas is adjusted by increasing or decreasing stepwise, during processing, the amount of the heat conducting gas discharged from the middle of a feed channel of the heat conducting gas.  
   
   
       10 . A vacuum processing method according to any one of  claims 7  to  9 , wherein the films constituting a plurality of layers of the sample have a damascene structure.