Metal removal

Abstract

Methods are described herein for etching metal films, such as cobalt and nickel, which are difficult to volatize. The methods include exposing a metal film to a chlorine-containing precursor (e.g. Cl 2 ). Chlorine is then removed from the substrate processing region. A carbon-and-nitrogen-containing precursor (e.g. TMEDA) is delivered to the substrate processing region to form volatile metal complexes which desorb from the surface of the metal film. The methods presented remove metal while very slowly removing the other exposed materials.

1 . A method of etching metal from a substrate, the method comprising:
 transferring the substrate into a substrate processing region;   flowing a halogen-containing precursor into the substrate processing region, wherein the substrate processing region is plasma-free during the flowing of the halogen-containing precursor;   purging the substrate processing region with a relatively inert gas to remove the halogen-containing precursor from the substrate processing region;   flowing a carbon-and-nitrogen-containing precursor in to the substrate processing region, wherein the substrate processing region is plasma-free during the flowing of the carbon-and-nitrogen-containing precursor and flowing of the carbon-and-nitrogen-containing precursor occurs after purging the substrate processing region;   removing metal from the substrate; and   removing the substrate from the substrate processing region.   
     
     
         2 . The method of  claim 1  wherein the carbon-and-nitrogen-containing precursor comprises one of o-phenylenediamine, p-phenylenediamine, m-phenylenediamine or R 2 —N—[CH 2 ] m N—R 2 , wherein m is 1, 2 or 3 and R is H, CH 3  or C 2 H 5 . 
     
     
         3 . The method of  claim 1  further comprising purging the substrate processing region with a relatively inert gas to remove the carbon-and-nitrogen-containing precursor from the substrate processing region and then repeating the operations of flowing the halogen-containing precursor, purging to remove the halogen-containing precursor and flowing the carbon-and-nitrogen-containing precursor. 
     
     
         4 . The method of  claim 1  wherein the metal consists of either cobalt or nickel. 
     
     
         5 . A method of etching metal from a substrate, the method comprising:
 flowing a halogen-containing precursor into a substrate processing region housing the substrate, wherein the substrate processing region is plasma-free during the flowing of the halogen-containing precursor;   removing unreacted halogen-containing precursor from the substrate processing region;   flowing a carbon-and-nitrogen-containing precursor into the substrate processing region, wherein the substrate processing region is plasma-free during the flowing of the carbon-and-nitrogen-containing precursor and flowing of the carbon-and-nitrogen-containing precursor occurs after removing unreacted halogen-containing precursor; and   removing metal from the substrate.   
     
     
         6 . The method of  claim 5  wherein the metal comprises at least one of cobalt and nickel. 
     
     
         7 . The method of  claim 5  wherein the metal consists of a single element. 
     
     
         8 . The method of  claim 5  wherein the carbon-and-nitrogen-containing precursor comprises tetramethylethylenediamine. 
     
     
         9 . The method of  claim 5  wherein the carbon-and-nitrogen-containing precursor comprises a carbon-nitrogen single bond. 
     
     
         10 . The method of  claim 5  wherein the carbon-and-nitrogen-containing precursor comprises at least two methyl groups. 
     
     
         11 . The method of  claim 5  wherein the halogen-containing precursor comprises at least one of chlorine or bromine. 
     
     
         12 . The method of  claim 5  wherein the halogen-containing precursor is a homonuclear diatomic halogen. 
     
     
         13 . The method of  claim 5  wherein the carbon-and-nitrogen-containing precursor consists of carbon, nitrogen and hydrogen. 
     
     
         14 . The method of  claim 5  wherein a pressure within the substrate processing region is between about 0.01 Torr and about 10 Torr during one or more of flowing the halogen-containing precursor or flowing the carbon-and-nitrogen-containing precursor. 
     
     
         15 . The method of  claim 5  wherein a temperature of the substrate is greater than or about −30° C. and less than or about 400° C. during flowing the halogen-containing precursor. 
     
     
         16 . The method of  claim 5  wherein a temperature of the substrate is greater than or about −30° C. and less than or about 400° C. during flowing the carbon-and-nitrogen-containing precursor.