Plasma etching apparatus

Abstract

A plasma detector is provided inside an upper electrode of a parallel plate type dry-etching apparatus. Upon reaching a particular pressure at the detector, the etching apparatus is deactivated. This deactivation may be used to replace an ineffective gas introducing plate. The plasma detector measures a pressure of the plasma at the backside of the gas-introducing plate, which has gas holes therein. As the gas holes increase during use of the apparatus, the pressure of the plasma at the backside of the gas increases, and the function of the apparatus is comprised. By detecting the pressure of the plasma, defective conditions in the apparatus may be detected.

1 - 7 . (canceled)  
   
   
       8 . An apparatus for etching a wafer, comprising: 
 an upper gas electrode, which has a cooling plate provided with gas supply holes and a gas-introducing plate with a plurality of gas holes;    a lower gas electrode over which the wafer is placed;    a first pressure gauge, which detects a first pressure between the cooling plate and the gas-introducing plate;    a second pressure gauge, which detects a second pressure between the gas-introducing plate and the lower electrode; and    a detector, which detects a difference between the first pressure and the second pressure, and which terminates the etching of the wafer when the difference in the pressures is greater than a predetermined value.    
   
   
       9 . An apparatus as recited in  claim 8 , wherein said upper gas electrode further comprises a jig, which fixes said gas-introducing plate to said cooling plate.  
   
   
       10 . An apparatus as recited in  claim 8 , wherein said first pressure gauge is provided between said gas-introducing plate and said cooling plate.  
   
   
       11 . An apparatus as recited in  claim 8 , wherein said first pressure increases as said gas holes of said gas-introducing plate increase in size.  
   
   
       12 . An apparatus as recited in  claim 9 , wherein said first pressure gauge is at a backside of said gas introducing plate.