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.

1 . A method of establishing a differential in the concentration of an additive on a surface of a workpiece, comprising: 
 having the additive adsorbed on the surface of the workpiece; and    applying an external influence to a portion of the surface without applying the external influence to an other portion of the surface,    wherein applying the external influence establishes a differential between a concentration of the additive adsorbed on the portion of the surface and a concentration of the additive adsorbed on the other portion of the surface.    
   
   
       2 . The method of  claim 1 , wherein applying the external influence comprises sweeping the portion of the surface in a solution.  
   
   
       3 . The method of  claim 2 , wherein sweeping the portion of the surface reduces the concentration of the additive on the portion of the surface.  
   
   
       4 . The method of  claim 3 , wherein the additive comprises at least one of an accelerator and a suppressor.  
   
   
       5 . The method of  claim 3  further comprising depositing a material from the solution to the surface of the workpiece, wherein less material gets deposited on the portion than on the other portion.  
   
   
       6 . The method of  claim 5 , wherein depositing is performed during or subsequent to applying the external influence.  
   
   
       7 . The method of  claim 5 , wherein the solution comprises at least one of an accelerator and a suppressor.  
   
   
       8 . The method of  claim 6 , wherein the solution comprises at least one of an accelerator and a suppressor.  
   
   
       9 . The method of  claim 2 , wherein the portion of the surface is a top portion and the other portion of the surface is a cavity portion.  
   
   
       10 . The method of  claim 9 , wherein the additive comprises at least one of an accelerator and a suppressor.  
   
   
       11 . The method of  claim 10 , wherein the solution comprises at least one of an accelerator and a suppressor.  
   
   
       12 . The method of  claim 10 , wherein sweeping reduces the concentration of the additive on the top portion.  
   
   
       13 . The method of  claim 11  further comprising depositing a material from the solution to the surface of the workpiece, wherein more material gets deposited on the cavity portion than on the top portion.  
   
   
       14 . The method of  claim 13 , wherein depositing is performed during or subsequent to applying the external influence.  
   
   
       15 . The method of  claim 14 , wherein the material is copper.  
   
   
       16 . The method of  claim 14 , further comprising repeating the steps of having the additive adsorbed, applying the external influence to establish a differential and depositing the material.  
   
   
       17 . The method of  claim 12 , wherein an accelerator concentration on the top portion is lower than an accelerator concentration on the cavity portion after sweeping.  
   
   
       18 . The method of  claim 11 , wherein a suppressor concentration on the top portion is higher than a suppressor concentration on the cavity portion after sweeping.  
   
   
       19 . The method of  claim 11 , wherein a suppressor concentration on the top portion is higher than a suppressor concentration on the cavity portion and an accelerator concentration on the top portion is lower than an accelerator concentration on the cavity portion after sweeping.  
   
   
       20 . A method of establishing a differential in surface concentration of at least one additive adsorbed on a surface of a workpiece, the surface of the workpiece including a top portion and a cavity portion, the method comprising: 
 placing the surface of the workpiece in a solution;    applying an external influence to the top portion of the surface without applying the external influence to the cavity portion of the surface; and    altering relative concentrations of adsorbed additives to establish a differential between a concentration of the at least one additive adsorbed on the top portion of the surface and a concentration of the at least one additive adsorbed on the cavity portion of the surface.    
   
   
       21 . The method of  claim 20 , wherein applying the external influence comprises sweeping the top portion of the surface and thereby altering the relative concentration of adsorbed additives.  
   
   
       22 . The method of  claim 21 , wherein the at least one additive comprises an accelerator.  
   
   
       23 . The method of  claim 22 , wherein the solution comprises at least one of an accelerator and a suppressor.  
   
   
       24 . The method of  claim 23 , further comprising electrodepositing a conductor from the solution to the surface of the wafer while the differential exists.  
   
   
       25 . The method of  claim 24 , wherein electrodepositing comprises depositing less conductor on the top portion compared to the cavity portion.  
   
   
       26 . The method of  claim 25 , further comprising repeating the steps of applying, altering and electrodepositing.  
   
   
       27 . A method of selectively electroplating copper on a cavity portion of a conductive surface comprising a top portion, the method comprising: 
 having at least one additive species uniformly adsorbed on the cavity portion of the conductive surface and on the top portion of the conductive surface;    at least partially clearing off the at least one additive species adsorbed on the top portion;    delivering an electroplating solution to the conductive surface;    applying power to the conductive surface; and    depositing copper from the electroplating solution so that more copper deposits in the cavity portion than on the top portion.    
   
   
       28 . The method of  claim 27 , wherein at least partially clearing off is carried out by sweeping the top portion.  
   
   
       29 . The method of  claim 28 , wherein the at least one additive species comprises an accelerator species.  
   
   
       30 . The method of  claim 28 , wherein the at least one additive species comprises an inhibitor species.  
   
   
       31 . The method of  claim 29 , wherein the electroplating solution comprises at least one of an accelerator and an inhibitor.  
   
   
       32 . The method of  claim 30 , wherein the electroplating solution comprises at least one of an accelerator and an inhibitor.