In-situ pre-clean for electroplating process

Abstract

Embodiments of the invention generally provide a waveform to be applied to a seed layer prior to initiating plating operations, wherein the waveform is configured to remove organic contaminants from the seed layer. The application of the waveform generally includes applying a plurality of anodic pulses to the seed layer prior to an electrochemical deposition process and subsequent to the seed layer contacting a plating solution, and applying a cathodic pulse to the seed layer immediately following each of the plurality of anodic pulses. The waveform is generally provided by a power supply in electrical communication with a system controller configured to supply controlling signals to the power supply.

1 . A method for cleaning organic contaminants from a copper seed layer in an electrochemical plating system, comprising: 
 applying a plurality of anodic pulses to the seed layer prior to an electrochemical deposition process and subsequent to the seed layer contacting a plating solution; and    applying a cathodic pulse to the seed layer immediately following each of the plurality of anodic pulses.    
     
     
         2 . The method of  claim 1 , wherein an amplitude of a current density of each of the plurality of anodic pulses is between about 50 mA/cm 2  and about 150 mA/cm 2 .  
     
     
         3 . The method of  claim 1 , wherein an amplitude of a current density of each of the plurality of anodic pulses is between about 75 mA/cm 2  and about 125 mA/cm 2 .  
     
     
         4 . The method of  claim 1 , wherein a duration of each of the plurality of anodic pulses is between about 5 milliseconds and about 50 milliseconds.  
     
     
         5 . The method of  claim 1 , wherein a duration of each of the plurality of anodic pulses is between about 10 milliseconds and about 20 milliseconds.  
     
     
         6 . The method of  claim 1 , wherein an amplitude of a current density for the cathodic pulse is between about 75 mA/cm 2  and about 125 mA/cm 2 .  
     
     
         7 . The method of  claim 1 , wherein an amplitude of a current density for the cathodic pulse is between about 90 mA/cm 2  and about 100 mA/cm 2 .  
     
     
         8 . The method of  claim 1 , wherein a duration of the cathodic pulse is between about 10 milliseconds and about 100 milliseconds.  
     
     
         9 . The method of  claim 1 , wherein a duration of the cathodic pulse is at least five times a duration of each of the plurality of anodic pulses.  
     
     
         10 . The method of  claim 1 , wherein the plurality of anodic pulses comprises between about 2 and about 10 anodic pulses.  
     
     
         11 . The method of  claim 1 , wherein the plurality of anodic pulses comprises between about 3 and about 6 anodic pulses.  
     
     
         12 . A method for removing organic contamination from a copper seed layer overlying sub-quarter micron sized features formed onto a semiconductor substrate in an electrochemical plating system, the method comprising applying a cleaning waveform to the seed layer once the seed layer is immersed in an electrolyte solution, the cleaning waveform comprising: 
 at least one deposition pulse; and    at least one etch pulse, wherein the at least one deposition pulse has a long duration low magnitude positive current density, and wherein the at least one etch pulse has a short duration high magnitude negative current density.    
     
     
         13 . The method of  claim 12 , wherein the long duration low magnitude positive current density deposition pulse further comprises a deposition pulse having a current density of between about 50 mA/cm 2  and about 125 mA/cm 2  and a duration of between about 10 milliseconds and about 150 milliseconds.  
     
     
         14 . The method of  claim 12 , wherein the short duration high magnitude negative current density etch pulse further comprises an etch pulse having a current density of between about 50 mA/cm 2  and about 150 mA/cm 2  and a duration of between about 10 milliseconds and about 50 milliseconds.  
     
     
         15 . The method of  claim 13 , wherein the current density is between about 75 mA/cm 2  and about 100 mA/cm 2 .  
     
     
         16 . The method of  claim 13 , wherein the duration is between about 50 milliseconds and about 150 milliseconds.  
     
     
         17 . The method of  claim 14 , wherein the current density is between about 75 mA/cm 2  and about 125 mA/cm 2 .  
     
     
         18 . The method of  claim 14 , wherein the duration is between about 10 milliseconds and about 30 milliseconds.  
     
     
         19 . The method of  claim 12 , wherein the at least one deposition pulse comprises between about 3 and about 10 deposition pulses.  
     
     
         20 . The method of  claim 12 , wherein the at least one etch pulse comprises between about 3 and about 10 etch pulses.  
     
     
         21 . A method for electrochemically plating copper onto a seed layer, comprising: 
 immersing the seed layer in a plating solution while applying an electrical loading bias to the seed layer;    applying a cleaning waveform to the seed layer prior to initiating plating operations, the cleaning waveform comprising: 
 a plurality of cathodic pulses; and  
 a plurality of anodic pulses, the plurality of anodic pulses having a short duration and high current density; and  
   applying a electrical plating bias to the seed layer to plate copper thereon.    
     
     
         22 . The method of  claim 21 , wherein each of the plurality of cathodic pulses comprises a deposition pulse having a duration of between about 10 milliseconds and about 100 milliseconds and a current density of between about 75 mA/cm 2  and about 125 mA/cm 2 .  
     
     
         23 . The method of  claim 21 , wherein each of the plurality of anodic pulses comprises an etch pulse having a duration of between about 5 milliseconds and about 20 milliseconds and a current density of between about 75 mA/cm 2  and about 125 mA/cm 2 .  
     
     
         24 . The method of  claim 21 , wherein the plurality of anodic pulses comprises between about 2 and about 10 anodic pulses and wherein the plurality of cathodic pulses comprises between about 2 and about 10 cathodic pulses.  
     
     
         25 . A method for cleaning contaminants from a copper seed layer, comprising alternating the application of an anodic pulse and a cathodic pulse, wherein the cathodic pulses have a duration of between about 10 milliseconds and about 100 milliseconds and a current density of between about 75 mA/cm 2  and about 125 mA/cm 2 , and wherein the anodic pulses have a duration of between about 5 milliseconds and about 20 milliseconds and a current density of between about 75 mA/cm 2  and about 125 mA/cm 2 , the alternating application of the anodic pulse and the cathodic pulse occurring prior to commencing a plating process on the seed layer.  
     
     
         26 . The method of  claim 25 , wherein the alternating cathodic pulse and anodic pulse comprises between about 4 and about 20 total pulses.  
     
     
         27 . An electrochemical plating cell, comprising: 
 a plating cell container configured hold a plating solution therein;    a pivotally mounted lid member configured to support a substrate on a lower surface thereof such that the substrate is in electrical communication with a contact ring; and    a power supply in electrical communication with the contact ring, the power supply being configured to apply a plurality of anodic pulses to a seed layer deposited on the substrate prior to an electrochemical deposition process and subsequent to the seed layer contacting a plating solution and apply a cathodic pulse to the seed layer immediately following each of the plurality of anodic pulses.    
     
     
         28 . The electrochemical plating cell of  claim 27 , wherein the power supply is configured to generate an amplitude of between about 50 mA/cm 2  and about 150 mA/cm 2  for each of the plurality of anodic pulses.  
     
     
         29 . The electrochemical plating cell of  claim 27 , wherein the power supply is configured to generate a duration of between about 5 milliseconds and about 50 milliseconds between each of the plurality of anodic pulses.  
     
     
         29 . The electrochemical plating cell of  claim 27 , wherein the power supply is configured to generate an amplitude of between about 75 mA/cm 2  and about 125 mA/cm 2  for each of the cathodic pulses.  
     
     
         30 . The electrochemical plating cell of  claim 27 , wherein a duration of the cathodic pulse is at least five times a duration of each of the plurality of anodic pulses.  
     
     
         31 . An electrochemical plating cell, comprising: 
 a plating cell container configured hold a plating solution therein;    a pivotally mounted lid member configured to support a substrate on a lower surface thereof such that the substrate is in electrical communication with a contact ring;    means for applying a plurality of anodic pulses to a seed layer deposited on the substrate prior to an electrochemical deposition process and subsequent to the seed layer contacting a plating solution; and    means for applying a cathodic pulse to the seed layer immediately following each of the plurality of anodic pulses.    
     
     
         32 . The electrochemical plating cell of  claim 31 , wherein the means for applying comprises a power supply in electrical communication with a system controller configured to control the operation of the power supply.