Method of etching with NH3 and fluorine chemistries

Abstract

A method of etching a stack using a fluorine containing gas and an ammonia containing gas is provided. Generally, the stack is placed in a plasma processing chamber. A fluorine containing gas is flowed into the plasma processing chamber. An ammonia containing gas is flowed into the plasma processing chamber. A plasma is generated. The stack is then etched. In addition, a device for etching stacks on a substrate is provided. The device comprises: a plasma chamber with chamber walls; a plasma confinement device for reducing plasma contact with the chamber walls; a gas source; plasma generation and energizing device; and an exhaust system for pumping plasma away. The gas source comprises a fluorine containing gas source and an ammonia containing gas source.

1 - 15 . (Canceled)  
     
     
         16 . A method of etching a stack, comprising: 
 placing the stack in a plasma processing chamber;    flowing a fluorine containing gas into the plasma processing chamber;    flowing an ammonia containing gas into the plasma processing chamber;    generating a plasma; and    etching the stack.    
     
     
         17 . The method, as recited in claim  15 , further comprising confining the plasma to reduce plasma contact with chamber walls.  
     
     
         18 . The method, as recited in claim  15 , wherein the stack comprises a low dielectric constant layer and an etch stop layer over a substrate.  
     
     
         19 . The method, as recited in  claim 16 , wherein the fluorine containing gas and the ammonia containing gas are provided in an alternating manner and wherein a plasma is generated from the fluorine containing gas and a plasma is generated from the ammonia containing gas.  
     
     
         20 . The method, as recited in  claim 16 , wherein the confining the plasma comprises providing a plurality of spaced apart plasma rings.  
     
     
         21 . The method, as recited in  claim 20 , further comprising providing a pressure below 300 mTorr during the etching.  
     
     
         22 . The method, as recited in claim  15 , wherein the stack comprises a low dielectric constant material layer and an etch stop layer, wherein the low dielectric constant layer is etched by plasma generated from the ammonia containing gas and the etch stop layer is etched plasma generated from the fluorine containing gas.  
     
     
         23 . The method, as recited in claim  15 , further comprising stripping a photoresist mask within the plasma processing chamber wherein the stripping uses a plasma generated from an ammonia containing stripping gas.  
     
     
         24 . A method of etching a stack with at least one organic low dielectric constant layer, comprising: 
 placing the stack in a plasma processing chamber comprising a plasma chamber wall, a gas source, a plasma generation and energizing device, confinement rings and an exhaust system;    flowing an ammonia containing gas into the plasma processing chamber;    generating a plasma from the ammonia containing gas;    performing a first etch from the ammonia containing gas;    flowing a fluorine containing gas into the plasma processing chamber;    generating a plasma from the fluorine containing gas; and    performing a second etch from the fluorine containing gas.    
     
     
         25 . The method, as recited in  claim 24 , wherein the first etch etches the at least one organic low dielectric constant layer.  
     
     
         26 . The method, as recited in  claim 25 , wherein the stack further comprises an etch stop layer, wherein the second etch etches the etch stop layer.  
     
     
         27 . The method, as recited in  claim 26 , further comprising: 
 flowing an ammonia containing stripping gas into the plasma processing chamber;    generating a plasma from the ammonia containing gas; and    stripping a photoresist mask over the stack.    
     
     
         28 . The method, as recited in  claim 27 , wherein the ammonia containing stripping gas contains a fluorine containing gas.  
     
     
         29 . The method, as recited in  claim 28 , further comprising confining the plasma to reduce plasma contact with chamber walls wherein the confinement rings are used to confine the plasma.  
     
     
         30 . The method, as recited in  claim 24 , further comprising: 
 flowing an ammonia containing stripping gas into the plasma processing chamber;    generating a plasma from the ammonia containing gas; and    stripping a photoresist mask over the stack.    
     
     
         31 . The method, as recited in  claim 30 , wherein the ammonia containing stripping gas contains a fluorine containing gas.  
     
     
         32 . The method, as recited in  claim 24 , further comprising confining the plasma to reduce plasma contact with chamber walls wherein the confinement rings are used to confine the plasma.  
     
     
         33 . A method of etching a stack with at least one organic low dielectric constant layer, comprising: 
 placing the stack in a plasma processing chamber comprising a plasma chamber wall, a gas source, a plasma generation and energizing device, a plurality of spaced apart confinement rings, and an exhaust system;    flowing a fluorine containing gas into the plasma processing chamber;    flowing an ammonia containing gas into the plasma processing chamber;    generating a plasma;    confining the plasma with the confinement rings;    maintaining the pressure below 300 mTorr; and    etching the stack with the generated plasma.    
     
     
         34 . The method, as recited in  claim 33 , wherein a the organic low dielectric constant material is below a photoresist mask, further comprising stripping the photoresist mask, wherein the stripping comprises