Semiconductor production apparatus

Abstract

A semiconductor production apparatus for etching a semiconductor wafer arranged in a container and having a film on the surface thereof, by a plasma generated in the container is disclosed. The temporal change of the amount of light is detected for at least two wavelengths obtained from the wafer surface for a predetermined period of the processing time. The etching condition is determined by comparing a predetermined time with the time length between a time point at which the temporal change amount of the light of one of the two wavelengths assumes a maximum value and a time point at which the amount of light of the other wavelength assumes a minimum value.

1 . A semiconductor production apparatus for etching a semiconductor wafer arranged in a container and having a film on the surface thereof, by use of a plasma generated in said container, comprising: 
 a detector for detecting the temporal change of the amount of light for at least two wavelengths obtained from the surface of said wafer for a predetermined period of said processing time; and    a determining means for determining the etching condition by comparing a predetermined time with the time length between a time point at which the temporal change amount assumes a maximum value for the light of one of said two wavelengths and a time point at which the amount of light for the other wavelength assumes a minimum value.    
   
   
       2 . A semiconductor production apparatus according to  claim 1 , wherein said determining means determines the thickness of said etched film in the case where said time length is not longer than said predetermined value.  
   
   
       3 . A semiconductor production apparatus according to  claim 1 , wherein said determining means stops said etching process upon determination that said time length is not longer than said predetermined value.  
   
   
       4 . A semiconductor production apparatus for etching a semiconductor wafer arranged in a container and having a film on the surface thereof, by use of a plasma generated in said container, comprising: 
 a detector for detecting the interference of the light from said wafer surface during a predetermined period of said etching process;    a comparator means for comparing a predetermined value with the time length between a time point at which the temporal change of the amount of light having one of at least said two wavelengths output from said detector assumes a maximum value and a time point at which the amount of light having the other wavelength assumes a minimum value; and    a control unit for adjusting said etching process upon receipt of the output of said comparator means.    
   
   
       5 . A semiconductor production apparatus according to  claim 4 , wherein said control unit stops said etching process upon determination that said time length is not longer than said predetermined value.  
   
   
       6 . A semiconductor production apparatus for etching a semiconductor wafer arranged in a container and including a plurality of film layers having a first film formed on the surface of said semiconductor wafer and a second film formed above said first film, by use of a plasma generated in said container, comprising: 
 a light detector for detecting the temporal change of the amount of light having a plurality of wavelengths obtained from said wafer surface during a predetermined time when said second film is etched; and    a detection means for detecting the thickness of said first film based on a specific waveform obtained from the output of said detector.    
   
   
       7 . A semiconductor production apparatus according to  claim 6 , wherein upon detection by said detector of a temporal change of the amount of the interference light from said wafer surface for a plurality of wavelengths, said detection means detects a unique change of the output of said light detector.