Damascene fabrication with electrochemical layer removal

Abstract

The present application discloses process comprising providing a wafer, the wafer comprising an inter-layer dielectric (ILD) having a feature therein, an under-layer deposited on the ILD, and a barrier layer deposited on the under-layer, and a conductive layer deposited in the feature, placing the wafer in an electrolyte, such that at least the barrier layer is immersed in the electrolyte, and applying an electrical potential between the electrode and the wafer. Also disclosed is an apparatus comprising a vessel having an electrolyte therein, a first electrode at least partially immersed in the electrolyte, the first electrode comprising a wafer comprising an inter-layer dielectric (ILD) having a feature therein, an under-layer deposited on the ILD layer, a barrier layer deposited on the under-layer and a conductive layer deposited in the feature, a second electrode at least partially immersed in the electrolyte, and a potential source for applying a potential difference between the first and second electrodes. Other embodiments are also disclosed and claimed.

1 .- 22 . (canceled)  
     
     
         23 . An apparatus comprising: 
 a vessel having an electrolyte therein;    a first electrode at least partially immersed in the electrolyte, the first electrode comprising a wafer comprising an inter-layer dielectric (ILD) having a feature therein, an under-layer deposited on the ILD layer, a barrier layer deposited on the under-layer and a conductive layer deposited in the feature;    a second electrode at least partially immersed in the electrolyte; and    a potential source for applying a potential difference between the first and second electrodes.    
     
     
         24 . The apparatus of  claim 23  wherein the electrolyte has a pH equal to or greater than 10.  
     
     
         25 . The apparatus of  claim 23  wherein the electrolyte comprises a solution of potassium hydroxide (KOH), sodium hydroxide (NaOH), ammonium hydroxide (NH 4 OH) or tetra-methyl ammonium hydroxide (TMAH).  
     
     
         26 . The apparatus of  claim 23 , further comprising an additive in the electrolyte.  
     
     
         27 . The apparatus of  claim 26  wherein the additive is an oxidizer, a corrosion inhibitor, a surfactant, a buffer, a complexor, or combinations thereof.  
     
     
         28 . The apparatus of  claim 23  wherein the conductive layer is copper.  
     
     
         29 . The apparatus of  claim 23  wherein the barrier layer comprises ruthenium (Ru), rhodium (Rh), tantalum (Ta), iridium (Ir), osmium (Os), or alloys thereof containing nitrogen (N), silicon (Si) or carbon (C).  
     
     
         30 . The apparatus of  claim 23  wherein the under-layer includes titanium (Ti), titanium nitride (TiN), tungsten (W), tungsten nitride (WN) or tantalum nitride (TaN).  
     
     
         31 . The apparatus of  claim 23  wherein the electrical potential has a value equal to or greater than 0.5V relative to the saturated calomel reference electrode  
     
     
         32 . The apparatus of  claim 23 , further comprising a reference electrode at least partially immersed in the electrolyte.  
     
     
         33 . The apparatus of  claim 32  wherein the reference electrode is a saturated calomel electrode.