Methods for processing substrates having metal hard masks

Abstract

Methods of processing metal hard masks are provided herein. In some embodiments, a method for processing a metal hard mask layer having a tri-layer resist disposed thereon is provided. A pattern is etched from a patterned photoresist layer into a second anti-reflective layer using a first plasma comprising chlorine. The pattern is etched into a first anti-reflective layer using a second plasma formed from a second process gas. The second anti-reflective layer is removed using a third plasma comprising chlorine (Cl 2 ). The metal hard mask layer is etched using a fourth plasma comprising chlorine. The first anti-reflective layer is removed using a fifth plasma comprising oxygen (O 2 ). In some embodiments, the process may be performed in a single process chamber. In some embodiments, the metal hard mask layer may be a titanium nitride (TiN) hard mask.

1 . A method for processing a metal hard mask layer having a tri-layer resist disposed thereon, the tri-layer resist comprising a first anti-reflective layer, a second anti-reflective layer disposed over the first anti-reflective layer, and a patterned photoresist layer defining a pattern to be etched into the metal hard mask layer disposed above the second anti-reflective layer, the method comprising:
 etching the pattern from the patterned photoresist layer into the second anti-reflective layer using a first plasma formed from a first process gas comprising a chlorine containing gas;   etching the pattern from the second anti-reflective layer into the first anti-reflective layer using a second plasma formed from a second process gas;   removing the second anti-reflective layer using a third plasma formed from a third process gas comprising chlorine (Cl 2 );   etching the pattern from the first anti-reflective layer into the metal hard mask layer using a fourth plasma formed from a fourth process gas comprising a chlorine containing gas; and   removing the first anti-reflective layer using a fifth plasma formed from a fifth process gas comprising oxygen (O 2 ).   
     
     
         2 . The method of  claim 1 , wherein the process is performed in a single process chamber. 
     
     
         3 . The method of  claim 1 , wherein the metal hard mask layer comprises titanium nitride (TiN). 
     
     
         4 . The method of  claim 1 , wherein the first anti-reflective layer is a silicon-based anti-reflective layer. 
     
     
         5 . The method of  claim 1 , wherein the second anti-reflective layer comprises an organic anti-reflective layer. 
     
     
         6 . The method of  claim 1 , wherein the first anti-reflective layer comprises silicon nitride (SiN), silicon oxynitride (SiON), or silicon carbide (SiC), Si-rich anti-reflective coating (ARC) layer. 
     
     
         7 . The method of  claim 1 , wherein the first, second and third process gas comprise a non-fluorine chemistry. 
     
     
         8 . The method of  claim 1 , wherein the first process gas further comprises at least one of ethylene (C 2 H 4 ), argon (Ar), oxygen (O 2 ), chlorine (Cl 2 ), or helium (He). 
     
     
         9 . The method of  claim 1 , wherein the first process gas is provided at a flow rate of about 5 to about 200 sccm. 
     
     
         10 . The method of  claim 1 , wherein etching using the first plasma further comprises:
 providing about 400 to about 2000 W of source RF power; and   providing about 30 to about 300 W of bias RF power.   
     
     
         11 . The method of  claim 1 , wherein etching using the first plasma further comprises:
 maintaining the process chamber at a pressure of about 4 to about 20 mTorr.   
     
     
         12 . The method of  claim 1 , wherein the second process gas comprises oxygen and ethylene. 
     
     
         13 . The method of  claim 12 , wherein the second process gas comprises a ratio of oxygen to ethylene about 15:1 to about 1:15. 
     
     
         14 . The method of  claim 1 , wherein the second process gas is provided at a flow rate of about 10 to about 150 sccm. 
     
     
         15 . The method of  claim 1 , wherein etching using the second plasma further comprises:
 providing about 300 to about 1800 W of source RF power; and   providing about 50 to about 400 W of bias RF power.   
     
     
         16 . The method of  claim 1 , wherein etching using the second plasma further comprises:
 maintaining the process chamber at a pressure of about 4 to about 15 mTorr.   
     
     
         17 . The method of  claim 1 , wherein the fourth process gas is provided at a flow rate of about 25 to about 200 sccm. 
     
     
         18 . The method of  claim 1 , wherein etching using the fourth plasma further comprises:
 providing about 300 to about 1500 W of source RF power; and   providing about 25 to about 250 W of bias RF power.   
     
     
         19 . The method of  claim 1 , wherein etching using the fourth plasma further comprises:
 maintaining the process chamber at a pressure of about 3 to about 20 mTorr.