Electrochemical methods for the formation of protective features on metallized features

Abstract

Electrochemical processes and apparatus are described for forming a protective feature on the exposed surface of a metallized feature. The protective feature provides a diffusion barrier and protects the metallized feature from corrosion and contamination. Protective features formed from nickel, cobalt, and alloys of these metals are described.

1 . A method of forming a protective feature on a metallized feature formed on a microelectronic workpiece, the method comprising: 
 forming the metallized feature on the microelectronic workpiece, the metallized feature having an exposed surface; and    electrolytically depositing a conductive protective feature on the exposed surface of the metallized feature.    
   
   
       2 . The method of  claim 1  wherein the exposed surface is a top surface.  
   
   
       3 . The method of  claim 2 , wherein the metallized feature has at least one exposed sidewall.  
   
   
       4 . The method of  claim 3 , wherein the metallized feature has at least two exposed sidewalls.  
   
   
       5 . The method of  claim 4 , wherein the electrolytically depositing step further comprises depositing the conductive protective feature on the exposed top surface and the at least two exposed sidewalls.  
   
   
       6 . The method of  claim 1 , wherein the conductive protective feature comprises nickel, nickel alloys, cobalt, or cobalt alloys.  
   
   
       7 . The method of  claim 1 , wherein the metallized feature includes metals selected from the group comprising copper, copper alloys, aluminum, aluminum alloys, gold, silver, platinum, platinum alloys, and combinations thereof.  
   
   
       8 . The method of  claim 7 , wherein the metallized feature comprises copper.  
   
   
       9 . The method of  claim 1 , wherein the step of forming the metallized feature further comprises forming the metallized feature on a barrier layer comprising tantalum or titanium.  
   
   
       10 . The method of  claim 9 , wherein the step of forming the metallized feature further comprises depositing a seed layer on the barrier layer prior to formation of the metallized feature.  
   
   
       11 . The method of  claim 10 , wherein after formation of the metallized feature, a portion of the seed layer is removed prior to electrolytically depositing the conductive protective feature.  
   
   
       12 . A conductive feature on a microelectronic workpiece made by the method of  claim 1 .  
   
   
       13 . A method of forming a conductive protective feature on a metallized feature formed on a microelectronic workpiece having a front side and a backside, the method comprising: 
 forming a barrier layer on the front side of the microelectronic workpiece;    forming a seed layer exterior to the barrier layer formed on the front side of the microelectronic workpiece;    forming the metallized feature on the front side of the microelectronic workpiece exterior to the seed layer, the metallized feature having an exposed surface;    removing exposed portions of the seed layer;    activating the exposed surface of the metallized feature; and    electrolessly depositing a conductive protective feature on the exposed surface of the metallized feature.    
   
   
       14 . The method of  claim 13 , wherein the exposed surface is a top surface.  
   
   
       15 . The method of  claim 13 , wherein the metallized feature has at least one exposed sidewall.  
   
   
       16 . The method of  claim 15 , wherein the metallized feature has at least two exposed sidewalls.  
   
   
       17 . The method of  claim 16 , wherein the electrolessly depositing step further comprises depositing the conductive protective feature on an exposed top surface and the at least two exposed sidewalls.  
   
   
       18 . The method of  claim 13 , wherein the conductive protective feature comprises nickel, nickel alloys, cobalt, or cobalt alloys.  
   
   
       19 . The method of  claim 18 , wherein the conductive protective feature comprises the alloys of nickel-tungsten-phosphorus, nickel-tungsten-boron, cobalt-tungsten-phosphorus, cobalt-tungsten-boron, nickel-molybdenum-phosphorous, cobalt-molybdenum-phosphorous, nickel-molybdenum-boron and cobalt-molybdenum-boron.  
   
   
       20 . The method of  claim 13 , wherein the metallized feature comprises copper, copper alloys, aluminum, aluminum alloys, gold, silver, platinum, platinum alloys, and combinations thereof.  
   
   
       21 . The method of  claim 20 , wherein the metallized feature comprises copper.  
   
   
       22 . The method of  claim 13 , wherein the barrier layer comprises tantalum or titanium.  
   
   
       23 . A microelectronic workpiece including a conductive feature formed by the method of  claim 13 .  
   
   
       24 . A conductive feature on a microelectronic workpiece formed over a titanium or tantalum barrier layer comprising: 
 an electrochemically deposited metallized feature having an exposed surface; and    a conductive protective feature electrochemically deposited on the metallized feature exterior to the exposed surface.    
   
   
       25 . The conductive feature of  claim 21 , wherein the conductive protective feature comprises nickel, nickel alloys, cobalt, or cobalt alloys.  
   
   
       26 . An apparatus for use in a manufacturing line for providing conductive features on a microelectronic workpiece, the apparatus comprising: 
 an input section for receiving a microelectronic workpiece, a surface of the microelectronic workpiece comprising a barrier feature, a seed layer formed exterior to the barrier feature, and a photoresist feature;    a bulk metallization station for electrochemically forming a metallized feature exterior to the seed layer;    a photoresist removal station for removing at least a portion of the photoresist feature resulting in a raised metallized feature with an exposed surface;    a seed layer removal station for removing at least a portion of the seed layer;    an electrochemical deposition station for electrochemically depositing a conductive protective feature on the exposed surface of the metallized feature; and    a barrier layer etching station for removing at least a portion of the barrier layer.    
   
   
       27 . The apparatus of  claim 26 , where the electrochemical deposition station comprises an electrolytic deposition chamber.  
   
   
       28 . The apparatus of  claim 26 , wherein the electrochemical deposition station comprises an electroless deposition chamber.  
   
   
       29 . The apparatus of  claim 26 , further comprising a photoresist developing station.