Method and apparatus for etching Si

Abstract

A method for dry-etching a Si substrate or a Si layer in a processing chamber includes the step of supplying an etching gas into the processing chamber, wherein the etching gas is a mixture gas including Cl 2 , O 2 and NF 3 and a residence time τ of the etching gas is equal to or greater than about 180 msec, the residence time τ being defined as: τ= pV/Q where p represents an inner pressure of the processing chamber; V, an effective volume of etching space formed on the Si substrate or the Si layer; and Q, a flow rate of the etching gas.

1 - 6 . (canceled)  
   
   
       7 . An apparatus for etching a Si substrate or a Si layer, comprising: 
 a processing chamber which is provided with a gas inlet and a gas outlet, and removably accommodates therein the Si substrate or an object having the Si layer;    an etching gas supply unit which mixes Cl 2 , O 2  and NF 3  to provide an etching gas and supplies the etching gas to the processing chamber through the gas inlet;    a plasma generator for generating a plasma of the etching gas;    a discharge unit which evacuates an interior of the processing chamber through the gas outlet to maintain an inner pressure of the processing chamber at a level,    wherein etching of the Si substrate or the Si layer is carried out while maintaining a residence time τ at a level equal to or greater than about 180 msec, the residence time τ being defined as:      τ= pV/Q      where p represents an inner pressure of the processing chamber; V, an effective volume of etching space formed on the Si substrate or the Si layer; and Q, a flow rate of the etching gas.    
   
   
       8 . The apparatus of  claim 7 , wherein the etching gas supply unit supplies the etching gas into the processing chamber such that a flow rate of the etching gas is equal to or less than about 100 sccm.  
   
   
       9 . The apparatus of  claim 7 , wherein the discharge unit maintains the inner pressure of the processing chamber at a level ranging from about 20 mtorr to about 200 mtorr.  
   
   
       10 . The apparatus of  claim 7 , further comprising an upper electrode and a lower electrode in the processing chamber wherein a distance between the upper electrode and the lower electrode ranges from about 30 mm to about 300 mm.