Forming Through-Substrate Vias by Electrofilling

Abstract

A plurality of through holes in a workpiece are filled with a solid conductive material. The workpiece is immersed in an electroplating solution, with the through holes covered at one end by a portion of a conductive plating base. The electroplating solution is permitted to fill the through holes in the workpiece and contact the portion of the conductive plating base. A voltage applied to the conductive plating base enables an electroplating operation that deposits the solid conductive material on the portion of the conductive plating base to thereby fill the through holes with the solid conductive material.

1 . An assembly adapted for insertion in a bath of electroplating solution for an electroplating operation on a workpiece, the workpiece having formed therein a plurality of through holes, wherein each said through hole has a first end and a second end, comprising:
 a workpiece holder adapted to hold said workpiece such that said first ends of said through holes of said workpiece permit said electroplating solution to fill said through holes when said assembly is inserted in said bath;   a conductive plating base positioned against a surface of said workpiece and having a portion that covers said second ends of said through holes and contacts the electroplating solution that fills said through holes when said assembly is inserted in said bath, wherein said conductive plating base is electrically accessible externally of said electroplating solution when said assembly is inserted in said bath to permit application of a voltage to said conductive plating base to conduct an electroplating operation in said bath; and   a compression apparatus coupled to said workpiece holder pressing said conductive plating base against said surface of said workpiece with said portion covering said second ends of said through holes.   
     
     
         2 . The assembly of  claim 1 , wherein said electroplating operation fills said through holes with a solid conductive material, and wherein said workpiece is a connection layer substrate for a multi-layer semiconductor apparatus. 
     
     
         3 . The assembly of  claim 2 , wherein said workpiece is one of a semiconductor die, a semiconductor wafer, and a printed circuit board, and wherein said solid conductive material forms vias in said through holes. 
     
     
         4 . The apparatus of  claim 3 , wherein said conductive plating base is a sacrificial copper foil. 
     
     
         5 . The assembly of  claim 1 , including a sealing apparatus that seals a further portion of said conductive plating base from contact with said electroplating solution when said assembly is inserted in said bath. 
     
     
         6 . The apparatus of  claim 5 , wherein:
 said workpiece holder includes a first plate and a second plate; and   said compression apparatus includes a fastening arrangement coupling said first and second plates of said workpiece holder, and wherein said workpiece, said conductive plating base and said sealing apparatus are disposed between said first and second plates.   
     
     
         7 . The apparatus of  claim 6 , wherein said sealing apparatus includes a first seal adjacent said workpiece and having therein an opening aligned with said workpiece. 
     
     
         8 . The apparatus of  claim 7 , wherein said sealing apparatus includes a second seal adjacent said conductive plating base, and wherein said conductive plating base and said workpiece are disposed between said first and second seals. 
     
     
         9 . The apparatus of  claim 8 , wherein said first seal is adjacent said first plate, and wherein said first plate has formed therein an opening aligned with said opening in said first seal to permit said electroplating solution to fill said through holes when said assembly is inserted in said bath. 
     
     
         10 . The apparatus of  claim 7 , wherein said first seal is adjacent said first plate, and wherein said first plate has formed therein an opening aligned with said opening in said first seal to permit said electroplating solution to fill said through holes when said assembly is inserted in said bath. 
     
     
         11 . The apparatus of  claim 6 , wherein said first plate and said second plate of said workpiece holder, and said fastening arrangement of said compression apparatus are made of Polyvinylidene Fluoride (PVDF), and said sealing arrangement includes a Viton gasket. 
     
     
         12 . A method of filling a plurality of through holes in a workpiece with a solid conductive material, comprising:
 immersing the workpiece in an electroplating solution, with the through holes covered at one end by a portion of a conductive plating base; and   during said immersing,
 permitting the electroplating solution to fill the through holes in the workpiece and contact said portion of the conductive plating base, and 
 applying a voltage to the conductive plating base to enable an electroplating operation that deposits the solid conductive material on said portion of the conductive plating base to thereby fill the through holes with the solid conductive material. 
   
     
     
         13 . The method of  claim 12 , including preventing the electroplating solution from contacting a further portion of the conductive plating base. 
     
     
         14 . The method of  claim 13 , including forcibly pressing said portion of the conductive plating base against the workpiece. 
     
     
         15 . The method of  claim 13 , wherein said preventing includes sealing said further portion of the conductive plating base from the electroplating solution. 
     
     
         16 . The method of  claim 15 , wherein said sealing includes forcibly pressing a first seal against the conductive plating base. 
     
     
         17 . The method of  claim 16 , wherein said sealing includes forcibly pressing a second seal against the first seal. 
     
     
         18 . The method of  claim 15 , including forcibly pressing said portion of the conductive plating base against the workpiece. 
     
     
         19 . The method of  claim 18 , wherein said sealing includes forcibly pressing a first seal against the conductive plating base. 
     
     
         20 . The method of  claim 19 , wherein said sealing includes forcibly pressing a second seal against the first seal.