Method for removal of residue from a substrate

Abstract

A method for removing residues from a substrate. The residue is removed by exposing the substrate to a hydrogen-based plasma. After the substrate is exposed to the hydrogen-based plasma, the substrate may optionally be immersed in an aqueous solution including hydrogen fluoride.

What is claimed is:  
     
         1 . A method for removing residue from a substrate, comprising: 
 providing a substrate having a metallic residue thereon; and    exposing the substrate to a hydrogen-based plasma to volatize the metallic residue.    
     
     
         2 . The method of  claim 1  wherein the metallic residue comprises at least one of a metal-containing residue and a polymeric residue.  
     
     
         3 . The method of  claim 2  wherein the metal-containing residue comprises at least one metal selected from the group consisting of tantalum (Ta), titanium (Ti), tungsten (W) and hafnium (Hf).  
     
     
         4 . The method of  claim 1  wherein the hydrogen-based plasma comprises at least one of hydrogen (H 2 ), water vapor (H 2 O).  
     
     
         5 . The method of  claim 1  wherein the hydrogen-based plasma comprises hydrogen (H 2 ) and water vapor (H 2 O) at a H 2 :H 2 O flow ratio in a range from 20:1 to 100% of H 2 .  
     
     
         6 . The method of  claim 1  wherein the exposing step comprises: 
 providing hydrogen (H 2 ) and water vapor (H 2 O) at a H 2 :H 2 O flow ratio in a range from 20:1 to 100% of H 2 ;  
 maintaining the substrate at a temperature of about 100 to 300 degrees Celsius at a process chamber pressure between about 1 to 4 Torr;  
 applying about 1000 to 2000 W of microwave power at about 2.45 GHz to form the hydrogen-based plasma; and  
 exposing the substrate to the hydrogen-based plasma for about 40 to 200 seconds.  
 
     
     
         7 . The method of  claim 1  further comprising immersing the substrate in an aqueous solution including hydrogen fluoride after exposing the substrate to the hydrogen-based plasma.  
     
     
         8 . The method of  claim 7  wherein the aqueous solution comprises between 0.5 and 12% by volume of hydrogen fluoride.  
     
     
         9 . The method of  claim 8  wherein the aqueous solution further comprises between 0.5 and 15% by volume of nitric acid (HNO 3 ).  
     
     
         10 . The method of  claim 8  wherein the aqueous solution further comprises between 0.5 and 15% by volume of hydrogen chloride (HCl).  
     
     
         11 . The method of  claim 7  wherein the substrate is immersed in the aqueous solution for about 1 to 10 minutes.  
     
     
         12 . The method of  claim 7  wherein the immersing step comprises: 
 immersing the substrate in an aqueous solution comprising between 0.5 and 12% by volume of hydrogen fluoride and deionized water at a temperature of about 10 to 30 degrees Celsius for a duration of about 0.5 to 5 minutes.  
 
     
     
         13 . A method for removing metallic residue from a substrate, comprising: 
 providing a substrate having a metallic residue thereon;    exposing the substrate to a hydrogen-based plasma to volatize the metallic residue; and    immersing the substrate in an aqueous solution including hydrogen fluoride.    
     
     
         14 . The method of  claim 13  wherein the metallic residue comprises at least one of a metal-containing residue and a polymeric residue.  
     
     
         15 . The method of  claim 14  wherein the metal-containing residue comprises at least one metal selected from the group consisting of tantalum (Ta), titanium (Ti), tungsten (W) and hafnium (Hf).  
     
     
         16 . The method of  claim 13  wherein the hydrogen-based plasma comprises at least one of hydrogen (H 2 ), water vapor (H 2 O).  
     
     
         17 . The method of  claim 13  wherein the hydrogen-based plasma comprises hydrogen (H 2 ) and water vapor (H 2 O) at a H 2 :H 2 O flow ratio in a range from 20:1 to 100% of H 2 .  
     
     
         18 . The method of  claim 13  wherein the aqueous solution comprises between 0.5 and 12% by volume of hydrogen fluoride.  
     
     
         19 . The method of  claim 18  wherein the aqueous solution further comprises between 0.5 and 15% by volume of nitric acid (HNO 3 ).  
     
     
         20 . The method of  claim 18  wherein the aqueous solution further comprises between 0.5 and 15% by volume of hydrogen chloride (HCl).  
     
     
         21 . The method of  claim 13  wherein the substrate is immersed in the aqueous solution for about 1 to 10 minutes.  
     
     
         22 . The method of  claim 13  wherein the exposing step comprises: 
 providing hydrogen (H 2 ) and water vapor (H 2 O) at a H 2 :H 2 O flow ratio in a range from 20:1 to 100% of H 2 ;  
 maintaining the substrate at a temperature of about 100 to 300 degrees Celsius at a process chamber pressure between about 1 to 4 Torr;  
 applying about 1000 to 2000 W of microwave power at about 2.45 GHz to form the hydrogen-based plasma; and  
 exposing the substrate to the hydrogen-based plasma for about 40 to 200 seconds.  
 
     
     
         23 . The method of  claim 13  wherein the immersing step comprises: 
 immersing the substrate in an aqueous solution comprising between 0.5 and 12% by volume of hydrogen fluoride and deionized water at a temperature of about 10 to 30 degrees Celsius for a duration of about 0.5 to 5 minutes.