Method and apparatus for remote plasma treatment for reducing metal oxides on a metal seed layer

Abstract

Method and apparatus for reducing metal oxide surfaces to modified metal surfaces and cooling the metal surfaces are disclosed. By exposing a metal oxide surface to remote plasma, the metal oxide surface on a substrate can be reduced to pure metal. A remote plasma apparatus can treat the metal oxide surface as well as actively cool, load/unload, and move the substrate within a single standalone apparatus. The remote plasma apparatus can be configured to actively cool the substrate during and/or after reducing the metal oxide to pure metal using an active cooling system. The active cooling system can include one or more of an actively cooled pedestal, an actively cooled showerhead, and one or more cooling gas inlets for delivering cooling gas to cool the substrate.

What is claimed is: 
     
         1 . A remote plasma apparatus comprising:
 a processing chamber;   a substrate support for holding a substrate with a metal seed layer in the processing chamber, wherein a portion of the metal seed layer of the substrate has been converted to oxide of the metal;   a remote plasma source over the substrate support;   a showerhead comprising a plurality of through-holes and positioned between the remote plasma source and the substrate support; and   a controller configured with instructions for performing the following operations:
 form a remote plasma of a reducing gas species in the remote plasma source; 
 expose the metal seed layer of the substrate to the remote plasma in the processing chamber under conditions that reduce the oxide of the metal; and 
 move the substrate away from the substrate support and towards the showerhead to position the substrate closer to the showerhead, wherein the showerhead is actively cooled to a temperature below about 30° C. so that a temperature of the substrate is lower when closer to the actively cooled showerhead than when further away from the actively cooled showerhead. 
   
     
     
         2 . The remote plasma apparatus of  claim 1 , further comprising one or more cooling gas inlets for delivering cooling gas into the processing chamber, wherein the one or more cooling gas inlets are positioned above the substrate support. 
     
     
         3 . The remote plasma apparatus of  claim 2 , wherein the controller is further configured with instructions for flowing the cooling gas from the one or more cooling gas inlets to cool the substrate after completion of exposing the metal seed layer to the remote plasma, wherein flowing the cooling gas cools the substrate to a temperature of about 30° C. or less. 
     
     
         4 . The remote plasma apparatus of  claim 2 , wherein the cooling gas includes at least one of argon, helium, or nitrogen. 
     
     
         5 . The remote plasma apparatus of  claim 2 , wherein a temperature of the cooling gas is between about −270° C. and about 30° C. 
     
     
         6 . The remote plasma apparatus of  claim 1 , further comprising:
 one or more movable members in the processing chamber configured to move the substrate to a plurality of positions between the showerhead and the substrate support, wherein a distance between the showerhead and the substrate support for the plurality of positions is between about 0.05 inches and about 0.75 inches.   
     
     
         7 . The remote plasma apparatus of  claim 1 , wherein the showerhead is actively cooled during exposure of the metal seed layer to the remote plasma. 
     
     
         8 . The remote plasma apparatus of  claim 1 , wherein the showerhead is actively cooled after completion of exposing the metal seed layer to the remote plasma. 
     
     
         9 . The remote plasma apparatus of  claim 1 , wherein the controller is further configured with instructions for transferring the substrate to an electroplating apparatus after cooling the substrate. 
     
     
         10 . The remote plasma apparatus of  claim 9 , wherein the remote plasma apparatus is part of the electroplating apparatus. 
     
     
         11 . The remote plasma apparatus of  claim 1 , wherein the substrate support includes a pedestal with one or more fluid channels to actively cool or actively heat the pedestal. 
     
     
         12 . The remote plasma apparatus of  claim 11 , wherein the controller is further configured with instructions for maintaining a temperature of the pedestal between about −10° C. and about 150° C. 
     
     
         13 . A remote plasma apparatus comprising:
 a processing chamber;   a substrate support for holding a substrate with a metal seed layer in the processing chamber, wherein a portion of the metal seed layer of the substrate has been converted to oxide of the metal;   a remote plasma source over the substrate support;   one or more cooling gas inlets above the substrate support in the processing chamber;   a showerhead comprising a plurality of through-holes and positioned between the remote plasma source and the substrate support; and   a controller configured with instructions for performing the following operations:
 form a remote plasma of a reducing gas species in the remote plasma source; 
 expose the metal seed layer of the substrate to the remote plasma in the processing chamber under conditions that reduce the oxide of the metal; and 
 cool the substrate actively to a temperature of about 30° C. or less by flowing a cooling gas onto the substrate using the one or more cooling gas inlets after completion of exposing the metal seed layer to the remote plasma. 
   
     
     
         14 . The remote plasma apparatus of  claim 13 , wherein a temperature of the cooling gas is between about −270° C. and about 30° C., the temperature of the substrate being actively cooled by the cooling gas to 30° C. or less in a span of about 100 seconds or less. 
     
     
         15 . The remote plasma apparatus of  claim 13 , wherein the one or more cooling gas inlets are positioned to provide the cooling gas through the showerhead and/or from an area peripheral to the substrate support. 
     
     
         16 . The remote plasma apparatus of  claim 13 , wherein the controller is further configured with instructions for:
 maintaining a temperature of the showerhead below about 30° C. so that a temperature of the substrate is lower when closer to the showerhead than when further away from the showerhead; and   moving the substrate towards the showerhead to further cool the substrate after completion of exposing the metal seed layer to the remote plasma.   
     
     
         17 . The remote plasma apparatus of  claim 13 , wherein the controller is further configured with instructions for transferring the substrate to an electroplating apparatus after cooling the substrate. 
     
     
         18 . The remote plasma apparatus of  claim 17 , wherein the remote plasma apparatus is part of the electroplating apparatus. 
     
     
         19 . The remote plasma apparatus of  claim 13 , wherein the substrate support includes a pedestal with one or more fluid channels to actively cool or actively heat the pedestal. 
     
     
         20 . The remote plasma apparatus of  claim 19 , wherein the controller is further configured with instructions for maintaining a temperature of the pedestal between about −10° C. and about 150° C.