Plating method and apparatus that creates a differential between additive disposed on a top surface and a cavity surface of a workpiece using an external influence

Abstract

The present invention relates to methods and apparatus for plating a conductive material on a substrate surface in a highly desirable manner. The invention removes at least one additive adsorbed on the top portion of the workpiece more than at least one additive disposed on a cavity portion, thereby allowing plating of the conductive material take place before the additive fully re-adsorbs onto the top portion and causing greater plating of the cavity portion relative to the top portion.

I claim:  
     
         1 . An apparatus for plating a conductive top surface of a workpiece with a conductor disposed in an electrolyte that exists on the top surface of the workpiece, the conductive top surface of the workpiece including a top portion and a cavity portion, and having at least one additive adsorbed thereon the apparatus comprising: 
 an anode used to which power can be applied, thereby creating an electric field between the anode and the top surface of the workpiece and allowing plating of the top surface to occur;    a mask disposed in proximity to the top surface of the workpiece between the anode and the workpiece and capable of causing physical sweeping of a first portion of the at least one additive adsorbed on the top portion of the workpiece due to relative movement between the mask and the workpiece, thereby reducing an amount of the first portion of the additive adsorbed on the top portion, and thereby the amount of conductor plated onto the top portion of the workpiece, for a period of time.    
     
     
         2 . The apparatus according to  claim 1 , wherein the mask is positioned to make physical contact with the top portion of the workpiece.  
     
     
         3 . The apparatus according to  claim 1  wherein the mask in made of an insulator.  
     
     
         4 . The apparatus according to  claim 1  wherein the mask includes an open area through which the electrolyte and a plating current can pass to an area of the workpiece corresponding to the open area of mask during application of power.  
     
     
         5 . The apparatus according to  claim 4  further including a DC power source that provides DC power during plating.  
     
     
         6 . The apparatus according to  claim 5  wherein a current pulse with a first current density is formed within the open area of the movable mask between the anode and the area of the workpiece, the first current density being greater than a second current density that exists in another area of the workpiece that is not covered by the moveable mask.  
     
     
         7 . The apparatus according to  claim 6  wherein, over a period of time, a plurality of current pulses are formed between the anode and different areas of the workpiece.  
     
     
         8 . The apparatus according to  claim 7  wherein the plurality of current pulses, summed together, equal a DC current provided by the DC power source.  
     
     
         9 . The apparatus according to  claim 4 , wherein the mask is positioned to make physical contact with the top portion of the workpiece.  
     
     
         10 . The apparatus according to  claim 9  wherein the mask comprises an insulator.  
     
     
         11 . The apparatus according to  claim 10  wherein the mask includes an abrasive that can assist in reducing an amount of the first portion of the additive adsorbed on the top portion.  
     
     
         12 . The apparatus according to  claim 1  wherein the relative movement between the mask and the workpiece results in a linear motion.  
     
     
         13 . The apparatus according to  claim 1  wherein the relative movement between the mask and the workpiece results in a reciprocating linear motion.  
     
     
         14 . The apparatus according to  claim 1  wherein the relative movement between the mask and the workpiece results in an orbital motion.  
     
     
         15 . The apparatus according to  claim 1  wherein the relative movement between the mask and the workpiece results in a reciprocating orbital motion.  
     
     
         16 . The apparatus according to  claim 1  wherein the mask comprises an insulator.  
     
     
         17 . The apparatus according to  claim 16  wherein the mask includes an abrasive that can assist in reducing an amount of the first portion of the additive adsorbed on the top portion.  
     
     
         18 . The apparatus according to  claim 17  wherein the mask includes an open area through which the electrolyte and a plating current can pass to an area of the workpiece corresponding to the open area of mask during application of power.  
     
     
         19 . The apparatus according to  claim 18 , wherein the mask is positioned to make physical contact with the top portion of the workpiece.  
     
     
         20 . The apparatus according to  claim 19  wherein the relative movement between the mask and the workpiece results in a linear motion.  
     
     
         21 . The apparatus according to  claim 19  wherein the relative movement between the mask and the workpiece results in a reciprocating linear motion.  
     
     
         22 . The apparatus according to  claim 19  wherein the relative movement between the mask and the workpiece results in an orbital motion.  
     
     
         23 . The apparatus according to  claim 19  wherein the relative movement between the mask and the workpiece results in a reciprocating orbital motion.  
     
     
         24 . The apparatus according to  claim 19 , wherein the mask is positioned to make physical contact with the top portion of the workpiece.  
     
     
         25 . The apparatus according to  claim 1  further including a pulsed power source that provides pulsed power during plating.  
     
     
         26 . The apparatus according to  claim 1  further including a DC power source.  
     
     
         27 . The apparatus according to  claim 26  wherein the DC power source operates in a current controlled mode in which the plating current is held substantially constant.  
     
     
         28 . The apparatus according to  claim 26  wherein the DC power operates in a voltage controlled mode in which a plating voltage is held substantially constant.