Reduction of defects in conductive layers during electroplating

Abstract

The present invention is a method and system to reduce defects in conductive surfaces during electrochemical processes. The system includes a first power supply and a second power supply. The first powers supply is configured to supply a first power between a conductive surface of a workpiece and an electrode of the system. The second power supply is configured to supply a second power between the conductive surface and the electrode when a switching unit switches from the first power from the first power supply to the second power from the second power supply in response to the conductive surface contacting the process solution.

1  A method of electroprocessing a conductive surface on a workpiece using a process solution and an electrode wetted by the process solution, the method comprising the steps of: 
 applying a first power between the conductive surface and the electrode using a first power supply;    contacting the conductive surface to the process solution; and    applying a second power between the surface and the electrode using a second power supply.    
     
     
         2 . The method of  claim 1  further comprising the step of sensing the contacting the conductive surface and generating a control signal in response to contacting the surface.  
     
     
         3 . The method of  claim 1 , wherein subsequent to the step of contacting, switching from the first power from the first power supply to the second power from the second power supply occurs.  
     
     
         4 . The method of  claim 3 , wherein switching from the first power to the second power supply occurs within a predetermined switching period.  
     
     
         5 . The method of  claim 4 , wherein the predetermined switching period is less than 100 milli seconds.  
     
     
         6 . The method of  claim 3 , wherein the switching begins at a partial contact time, when a partial contact is established between the conductive surface and the solution, and terminates at a full contact time when a full contact is established between the conductive surface and the solution.  
     
     
         7 . The method of  claim 1  further comprising the step of immersing the conductive surface into the process solution while continuing to apply the second power from the second power supply.  
     
     
         8 . The method of  claim 1 , wherein the first power from the first power supply is a contact power and a second power from the second power supply is a plating power.  
     
     
         9 . The method of  claim 7 , wherein the magnitude of the plating power is higher than the magnitude of the contact power.  
     
     
         10 . A semiconductor device manufactured using the method of  claim 1 .  
     
     
         11 . A system for electroprocessing a conductive surface on a workpiece using a process solution and an electrode while holding the workpiece with a workpiece carrier, the system comprising: 
 a first power supply configured to supply a first power between the conductive surface and the electrode;    a second power supply configured to supply a second power between the conductive layer and the electrode; and    a switching unit configured to switch between the first power and the second power in response to the conductive surface contacting the process solution.    
     
     
         12 . The system of  claim 11  further comprising a detector coupled to the switching unit configured to receive a contact signal and wherein the first power supply includes a current monitor configured to generate the contact signal in response to the conductive layer contacting the process solution.  
     
     
         13 . The system of  claim 12 , wherein the detector in response to the contact signal generates a command signal to switch from the first power to the second power.  
     
     
         14 . The system of  claim 11  wherein the switching unit includes solid state relays to switch from the first power to the second power.  
     
     
         15 . The system of  claim 12 , wherein the detector is an analog detector.