Semiconductor plating system workpiece support having workpiece-engaging electrode with submerged conductive current transfer areas

Abstract

A semiconductor workpiece holder used in electroplating systems for plating metal layers, such as copper, onto a semiconductor workpiece. The workpiece holder includes electrodes which extend and are partially submerged in a liquid plating bath. The electrodes have a contact face which bears against the workpiece and conducts current therebetween. The submersible portions of the electrodes are partially covered with a dielectric layer or surface and partially covered with a conductive layer or surface. The conductive surface is preferably spaced from the contact face and placed in direct contact with the plating bath to allow diversion of some of the plating current directly between the electrode and plating bath. Associated methods are also described.

We claim:  
     
         1 . A semiconductor workpiece holder for use in a semiconductor electroplating apparatus, comprising: 
 a workpiece support mounted to support a workpiece in position with at least a processed surface of the workpiece being in contact with a plating bath;    at least one electrode finger which is electrically conductive and capable of receiving and conducting electrical current supplied thereto, said at least one electrode finger extending from the workpiece support and having submersible portions which are shaped and arranged to extend from the workpiece support and be submerged within the plating bath during an electroplating process;    said at least one electrode finger having a contact forming part thereof which is adapted to engage a surface of the workpiece to conduct electrical current thereto;    wherein said submersible portions are provided with a dielectric surface over at least one submerged dielectric segment forming part of the submersible portions, and wherein said submersible portions are further provided with at least one electrically conductive segment forming part of the submersible portions for allowing part of the electrical current supplied to the electrode finger to be conducted directly to the plating bath along segments spaced from said contact.    
     
     
         2 . A semiconductor workpiece holder according to  claim 1  wherein said submersible portions are provided with said at least one submerged dielectric segment to an extent which provides over 25 percent of the submersible portions.  
     
     
         3 . A semiconductor workpiece holder according to  claim 1  wherein said submersible portions are provided with said at least one submerged dielectric segment over a range from about 25 percent to about 75 percent of the submersible portions.  
     
     
         4 . A semiconductor workpiece holder according to  claim 1  wherein said submersible portions include one of said submerged dielectric segments adjacent to the contact.  
     
     
         5 . A semiconductor workpiece holder according to  claim 1  wherein said submersible portions include: 
 a first submerged dielectric segment adjacent to the contact;  
 a first of electrically conductive segment adjacent to said first submerged dielectric segment;  
 a second submerged dielectric segment adjacent to said first electrically conductive segment.  
 
     
     
         6 . A semiconductor workpiece holder for use in a semiconductor electroplating apparatus, comprising: 
 a workpiece support mounted to support a workpiece in position with at least a processed surface of the workpiece being in contact with a plating bath;    at least one electrode finger which is electrically conductive and capable of receiving and conducting electrical current supplied thereto, said at least one electrode finger extending from the workpiece support and having submersible portions which are shaped and arranged to extend from the workpiece support and be submerged within the plating bath during an electroplating process;    said at least one electrode finger having a contact forming part thereof which is adapted to engage a surface of the workpiece to conduct electrical current thereto;    means for partially covering the said at least one electrode finger along said submersible portions to provide at least one submerged dielectric segment and at least one electrically conductive segment for allowing part of the electrical current supplied to the electrode finger to be conducted directly to the plating bath along segments spaced from said contact.    
     
     
         7 . A semiconductor workpiece holder according to  claim 6  wherein said submersible portions are provided with said at least one submerged dielectric segment to an extent which provides over 25 percent of the submersible portions.  
     
     
         8 . A semiconductor workpiece holder according to  claim 6  wherein said submersible portions are provided with said at least one submerged dielectric segment over a range from about 25 percent to about 75 percent of the submersible portions.  
     
     
         9 . A semiconductor workpiece holder according to  claim 6  wherein said submersible portions include one of said submerged dielectric segments adjacent to the contact.  
     
     
         10 . A semiconductor workpiece holder according to  claim 6  wherein said submersible portions include: 
 a first submerged dielectric segment adjacent to the contact;  
 a first of electrically conductive segment adjacent to said first submerged dielectric segment;  
 a second submerged dielectric segment adjacent to said first electrically conductive segment.  
 
     
     
         11 . A semiconductor workpiece holder for use in a semiconductor electroplating apparatus in electroplating copper to a semiconductor workpiece, comprising: 
 a workpiece support mounted to support a workpiece in position with at least a processed surface of the workpiece being in contact with a copper-containing plating bath;    at least one electrode finger which is electrically conductive and capable of receiving and conducting electrical current supplied thereto, said at least one electrode finger extending from the workpiece support and having submersible portions which are shaped and arranged to extend from the workpiece support and be submerged within the copper-containing plating bath during an electroplating process used to plate copper onto the semiconductor workpiece;    said at least one electrode finger having a contact forming part thereof which is adapted to engage a surface of the workpiece to conduct electrical current thereto;    means for partially covering the said at least one electrode finger along said submersible portions to provide at least one submerged dielectric segment and at least one electrically conductive segment for allowing part of the electrical current supplied to the electrode finger to be conducted directly to the copper-containing plating bath along segments spaced from said contact.    
     
     
         12 . A semiconductor workpiece holder according to  claim 11  wherein said submersible portions are provided with said at least one submerged dielectric segment to an extent which provides over 25 percent of the submersible portions.  
     
     
         13 . A semiconductor workpiece holder according to  claim 11  wherein said submersible portions are provided with said at least one submerged dielectric segment over a range from about 25 percent to about 75 percent of the submersible portions.  
     
     
         14 . A semiconductor workpiece holder according to  claim 11  wherein said submersible portions include one of said submerged dielectric segments adjacent to the contact.  
     
     
         15 . A semiconductor workpiece holder according to  claim 11  wherein said submersible portions include: 
 a first submerged dielectric segment adjacent to the contact;  
 a first of electrically conductive segment adjacent to said first submerged dielectric segment;  
 a second submerged dielectric segment adjacent to said first electrically conductive segment.  
 
     
     
         16 . A semiconductor workpiece holder for use in a semiconductor electroplating apparatus, comprising: 
 a workpiece support mounted to support a workpiece in position with at least a processed surface of the workpiece being in contact with a plating bath;    at least one electrode finger which is electrically conductive and capable of receiving and conducting electrical current supplied thereto, said at least one electrode finger extending from the workpiece support and having submersible portions which are shaped and arranged to extend from the workpiece support and be submerged within the plating bath during an electroplating process;    said at least one electrode finger having a contact forming part thereof which is adapted to engage a surface of the workpiece to conduct electrical current thereto;    means for conducting portions of the electrical current supplied to the electrode finger directly to the plating bath along segments spaced from said contact.    
     
     
         17 . A semiconductor workpiece holder according to  claim 16  wherein said submersible portions are provided with at least one submerged dielectric segment to an extent which provides over 25 percent of the submersible portions.  
     
     
         18 . A semiconductor workpiece holder according to  claim 16  wherein said submersible portions are provided with at least one submerged dielectric segment over a range from about 25 percent to about 75 percent of the submersible portions.  
     
     
         19 . A semiconductor workpiece holder according to  claim 16  wherein said submersible portions include at least one dielectric segment adjacent to the contact.  
     
     
         20 . A semiconductor workpiece holder according to  claim 16  wherein said submersible portions include: 
 a first submerged dielectric segment adjacent to the contact;  
 a first of electrically conductive segment adjacent to said first submerged dielectric segment;  
 a second submerged dielectric segment adjacent to said first electrically conductive segment.  
 
     
     
         21 . A method for plating metals onto the surface of a semiconductor article, comprising: 
 contacting a surface of the semiconductor article with an electrode at a contact face forming a part of the electrode;    submersing a portion of the electrode into a plating bath;    wetting a processed surface of the semiconductor article with the plating bath;    moving electrical current through the electrode and plating bath to cause electroplating to occur upon the processed surface of the semiconductor article;    diverting a portion of the moving electrical current directly between the electrode and the plating bath along at least one electrically conductive segment of the electrode which is spaced from said contact face.    
     
     
         22 . A method for plating copper onto the surface of a semiconductor article, comprising: 
 contacting a surface of the semiconductor article with an electrode at a contact face forming a part of the electrode;    submersing a portion of the electrode into a copper-containing plating bath;    wetting a processed surface of the semiconductor article with the copper-containing plating bath;    moving electrical current through the electrode and copper-containing plating bath to cause electroplating to occur upon the processed surface of the semiconductor article;    diverting a portion of the moving electrical current directly between the electrode and the copper-containing plating bath along at least one electrically conductive segment of the electrode which is spaced from said contact face.