Plasma processing method and apparatus using dynamic sensing of a plasma environment

Abstract

At least one control parameter such as power supplied to a plasma, process pressure, gas flow rate, and radio frequency bias power to a wafer is changed for an extremely short time as compared with an entire plasma processing time, to the extent that such a change does not affect the result of plasma processing on the wafer, to monitor a temporal change of a plasma state which occurs at the time of changing. A signal resulting from the monitoring method is used to control or diagnose the plasma processing, thereby making it possible to accomplish miniature etching works, high quality deposition, surface processing.

What is claimed is:  
     
         1 . A plasma processing apparatus comprising: 
 means for changing at least one parameter for controlling a process to the extent that the change does not affect the result of plasma processing on a wafer, said at least one parameter being selected from a group composed of power supplied to a plasma, a process pressure, a gas flow rate, and radio frequency bias power to the wafer; and    monitoring means for detecting a temporal change of a signal which occurs in a plasma state at the time of changing,    wherein said plasma processing apparatus performs a control of the plasma processing and/or diagnosis of said apparatus using said detected signal.    
     
     
         2 . A plasma processing apparatus according to  claim 1 , wherein 
 said changing means includes means for operating said plasma processing apparatus while intermittently cutting off the power supplied to the plasma or the radio frequency bias, as said parameter, to said wafer in repetition; and    said monitoring means includes means for detecting a signal indicative of a temporal change in the plasma state immediately after the power or the bias is cut off.    
     
     
         3 . A plasma processing apparatus comprising: 
 monitoring means for optically, electrically, magnetically, mechanically, thermally, pressure-wisely, temperature-wisely, or otherwise physically or chemically detecting a signal representative of a temporal change in a plasma state immediately after a plasma is lit or immediately after the plasma is cut off in said plasma processing apparatus; and    means for performing a control of plasma processing and/or diagnosis of said apparatus using said detected signal.    
     
     
         4 . A plasma processing apparatus comprising: 
 trigger means for changing at least one parameter for controlling a process to the extent that the change does not affect the result of plasma processing on a wafer, said at least one parameter being selected from a group including power supplied to a plasma, a process pressure, a gas flow rate, and radio frequency bias power to the wafer;    means for detecting a temporal change of a signal in a plasma light emission state which occurs in response to operation of said trigger means;    means for analyzing a plasma state or a process state utilizing a temporal change in plasma emission based on said detected signal; and    means for performing a control of plasma processing and/or diagnosis of said apparatus using data on a result of an analysis from said analyzing means.    
     
     
         5 . A plasma processing method comprising the steps of: 
 changing at least one parameter for controlling a process to the extent that the change does not affect the result of plasma processing on a wafer, said at least one parameter being selected from a group including power supplied to a plasma, a process pressure, a gas flow rate, and radio frequency bias power to the wafer;    detecting a signal representative of a temporal change of a plasma state at the time of said changing using optically, electrically, magnetically, mechanically, thermally, pressure-wisely, temperature-wisely, or otherwise physically or chemically monitoring means; and    performing a control of plasma processing and/or diagnosis of said apparatus using said detected signal.    
     
     
         6 . A plasma processing method comprising the steps of: 
 operating a plasma processing apparatus while intermittently cutting off the power supplied to the plasma;    detecting a signal representative of a temporal change in a plasma state immediately after the power is cut off, using optically electrically, magnetically, mechanically, thermally, pressure-wisely, temperature-wisely, or otherwise physically or chemically monitoring means; and    performing a control of plasma processing and/or diagnosis of said apparatus using said detected signal.    
     
     
         7 . A plasma processing method comprising the steps of: 
 detecting a signal representative of a temporal change in a plasma state immediately after a plasma is lit or immediately after the plasma is cut of fusing a monitoring detector; and    performing a control of plasma processing and/or diagnosis of said apparatus using said detected signal.    
     
     
         8 . A plasma processing method comprising the steps of: 
 changing at least one parameter for controlling a process to the extent that the change does not affect the result of plasma processing on a wafer, said at least one parameter being selected from a group including power supplied to a plasma, a process pressure, a gas flow rate, and radio frequency bias power to the wafer;    detecting a signal representative of a temporal change of a plasma light emission state which occurs in response to execution of said step of changing;    analyzing the plasma state or a process state utilizing a temporal change in plasma light emission represented by said detected signal; and    performing a control of plasma processing and/or diagnosis of said apparatus using data representative of a result of the analysis.