Specimen surface processing apparatus and surface processing method

Abstract

For a surface processing apparatus using a plasma, a mixed gas of a fluorine-containing gas and an oxygen gas is used as an ashing gas. A mixed gas of an oxygen gas and a fluorine-containing gas is introduced as an ashing gas. This allows the following steps to be carried out at the same time: removal of the silicon component left on the mask material surface and the mask material in the area including the cured mask layer and the like; and the removal of the carbon-based, and silicon-based deposits deposited on the inner wall of a vacuum chamber. In addition, the removal of the mask material is performed under low pressure, and in the subsequent step to a step using a mixed gas of a fluorine-containing gas and an oxygen gas, a plasma of only an oxygen gas is used. As a result, it becomes possible to reduce the damages (etching) to the film layer after etching.

What is claimed is:  
     
         1 . A sample surface processing apparatus, comprising: 
 a vacuum chamber; means for generating a plasma in the vacuum chamber; a sample stage for mounting a sample to be surface processed by the plasma thereon; and a power source for applying a high frequency bias to the sample, wherein the surface processing of the sample is performed by the plasma, and    said apparatus further comprising a function of monitoring the plasma emission intensity of a reaction product in the vacuum chamber, and the changes in interference light, automatically determining the state of the surface processing based on the monitor result, and controlling the high frequency bias.    
     
     
         2 . The sample surface processing apparatus according to  claim 1 , further comprising means for introducing a mixed gas of an oxygen gas and a fluorine-containing gas as an ashing gas into the vacuum chamber.  
     
     
         3 . A sample surface processing apparatus, comprising: 
 a vacuum chamber; a plasma source for generating a plasma in the vacuum chamber; a sample stage for mounting a sample thereon; and a power source for applying a high frequency bias to the sample, wherein the surface processing of the sample is performed by the plasma, and    said apparatus further comprising: means for introducing an oxygen gas or a mixed gas of an oxygen gas and a fluorine-containing gas into the vacuum chamber; and means for selectively supplying the oxygen gas or the mixed gas according to the surface state of the sample, and performing the surface processing of the sample within the scope of a processing pressure of not more than 2 Pa and a frequency of the plasma source of not less than 100 MHz.    
     
     
         4 . The sample surface processing apparatus according to  claim 3 , further comprising a function of monitoring the changes in plasma emission intensity of a reaction product in the vacuum chamber, automatically determining the state of the surface processing based on the monitor result, and performing switching between supplying the oxygen gas and the mixed gas, and switching of the high frequency bias.  
     
     
         5 . The sample surface processing apparatus according to  claim 4 , further comprising a display unit for displaying the change of the method for processing the sample based on the monitor result.  
     
     
         6 . A sample surface processing method comprising: generating a plasma in a vacuum chamber, and applying a high frequency bias to a sample stage for mounting a sample thereon, for performing the surface processing of the sample, wherein a mixed gas of an oxygen gas and a fluorine-containing gas is introduced into the vacuum chamber to perform the surface processing of the sample by the plasma.  
     
     
         7 . A sample surface processing method by a sample processing apparatus comprising: a vacuum chamber; means for generating a plasma in the vacuum chamber; a sample stage for mounting a sample to be processed thereon; and a power source for applying a high frequency bias to the sample, wherein the surface processing of the sample is performed by the plasma, 
 said method comprising:    introducing a mixed gas of an oxygen gas and a fluorine-containing gas into the vacuum chamber;    performing surface processing of the sample by the plasma;    monitoring the plasma emission intensity of a reaction product in the vacuum chamber, and the changes in interference light; and    automatically determining the state of the surface processing based on the monitor result, and performing switching between supplying the oxygen gas and the mixed gas, and switching of the high frequency bias.    
     
     
         8 . The sample surface processing method according to  claim 6  or  7 , further comprising: 
 a first step of applying a high frequency bias to the sample, and removing only the surface layer of the mask material of the sample by a plasma of the mixed gas of the oxygen gas and the fluorine-containing gas; and  
 a second step of stopping the high frequency bias, and removing the mask material left after the removal of the surface layer by an oxygen plasma.  
 
     
     
         9 . The sample surface processing method according to  claim 6  or  7 , wherein the pressure of the gas during surface processing is set at 0.2 to 2 Pa.  
     
     
         10 . The sample surface processing method according to  claim 6  or  7 , wherein the fluorine-containing gas is preferably any of CHF 3 , CH 2 F 2 , CF 4 , and SF 6 .  
     
     
         11 . The sample surface processing method according to  claim 6  or  7 , wherein the removal of the mask material of the sample and the removal of a deposit attached to the sidewall of the vacuum chamber are performed at the same time.  
     
     
         12 . The sample surface processing method according to  claim 6  or  7 , wherein the removal of a deposit attached to the inner wall of the vacuum chamber is performed.