Method and system for electroplating uniformity

Abstract

The present disclosure provides an electroplating system comprising an anode configured to move parallel to the surface of a cathode and a speed control unit operably connected to the anode and capable of varying the speed of the anode based on distance to edge regions of the cathode. The speed of the anode increases when the anode is proximate to the edge regions of the cathode to compensate for fringe deposition effects that would otherwise create non-uniform layer thickness. The anode is smaller than the cathode and moves across the cathode surface while the speed control unit adjusts movement speed to achieve uniform electroplating deposition. The system eliminates the need for masking while providing improved thickness uniformity across the deposited layer by controlling anode movement patterns that account for increased deposition rates near cathode edges.

1 . An electroplating system, comprising:
 an anode configured to move parallel to a surface of a cathode; and   a speed control unit operably connected to the anode and configured to vary a speed of the anode based on a distance of the anode to edge regions of the cathode, wherein the speed of the anode increases when the anode is proximate to the edge regions of the cathode.   
     
     
         2 . The electroplating system of  claim 1 , wherein the anode is smaller than the cathode. 
     
     
         3 . The electroplating system of  claim 2 , wherein the anode has a surface area that is less than 80% of a surface area of the cathode. 
     
     
         4 . The electroplating system of  claim 1 , wherein the speed control unit is configured to decrease the speed of the anode when the anode is positioned over a middle region of the cathode. 
     
     
         5 . The electroplating system of  claim 1 , wherein the cathode comprises a semiconductor substrate. 
     
     
         6 . The electroplating system of  claim 5 , wherein the semiconductor substrate is a wafer. 
     
     
         7 . The electroplating system of  claim 1 , further comprising a movement mechanism operably connected to the anode and configured to move the anode across the surface of the cathode. 
     
     
         8 . The electroplating system of  claim 7 , wherein the movement mechanism is configured to move the anode in multiple passes over the cathode surface. 
     
     
         9 . The electroplating system of  claim 8 , wherein the speed control unit is configured to adjust the speed of the anode during each pass based on sensor data or a pre-configured path. 
     
     
         10 . The electroplating system of  claim 1 , wherein the speed control unit is configured to vary the speed of the anode to compensate for fringe deposition effects that occur near the edge regions of the cathode. 
     
     
         11 . A method of electroplating, comprising:
 moving an anode along and parallel to a surface of a cathode; and   varying a speed of the anode based on a distance of the anode to edge regions of the cathode, wherein the speed of the anode is increased when the anode is proximate to the edge regions of the cathode.   
     
     
         12 . The method of  claim 11 , wherein the anode is smaller than the cathode. 
     
     
         13 . The method of  claim 12 , wherein the anode has a surface area that is less than 80% of a surface area of the cathode. 
     
     
         14 . The method of  claim 11 , wherein varying the speed of the anode further comprises decreasing the speed of the anode when the anode is positioned over a middle region of the cathode. 
     
     
         15 . The method of  claim 11 , further comprising a step of moving the anode in multiple passes over the cathode surface. 
     
     
         16 . The method of  claim 15 , wherein varying the speed of the anode is performed during each pass based on sensor data or a pre-configured path. 
     
     
         17 . An electroplating apparatus, comprising:
 a cathode;   an anode smaller than the cathode and positioned to move parallel to a surface of the cathode;   a movement mechanism operably connected to the anode; and   a speed control unit operably connected to the movement mechanism and configured to control the movement mechanism to increase a speed of the anode when the anode approaches the edge regions of the cathode to compensate for fringe deposition effects.   
     
     
         18 . The electroplating apparatus of  claim 17 , wherein the cathode comprises a semiconductor substrate. 
     
     
         19 . The electroplating apparatus of  claim 18 , wherein the semiconductor substrate is a wafer. 
     
     
         20 . The electroplating apparatus of  claim 17 , wherein the movement mechanism is configured to move the anode in multiple passes over the surface of the cathode.