Methods for three-dimensional integrated circuit through hole via gapfill and overburden removal

Abstract

Presented are methods and systems for fabricating three-dimensional integrated circuits having large diameter through-hole vias. One embodiment of the present invention provides a method of processing a wafer having holes for through-hole vias. The method comprises plating a gapfill metal on the wafer. The method also comprises chemically or electrochemically deplating a portion of the overburden metal. The method further comprises using chemical mechanical planarization to planarize the gapfill metal and to remove the remaining overburden metal. Another embodiment of the present invention is an integrated system comprising a process chamber for containing the wafer, a plating component integrated with the process chamber, and a deplating component integrated with the process chamber. The plating component is configured to electrochemically plate a gapfill metal onto the wafer to a least partially fill the holes. The deplating component is configured to chemically or to electrochemically remove a portion of the overburden metal formed by the plating component.

What is claimed is: 
     
         1 . A method of processing a wafer having holes for vias for integrated circuits comprising:
 plating a gapfill metal on the wafer to at least partially fill the holes while holding the wafer in a first process chamber;   chemically or electrochemically deplating a portion of overburden metal while holding the wafer in the first process chamber, and   moving the wafer to a chemical mechanical planarization chamber before complete removal of the overburden metal and using chemical mechanical planarization to planarize the gapfill metal and to remove the remaining overburden metal.   
     
     
         2 . The method of  claim 1 , wherein the gapfill metal comprises copper. 
     
     
         3 . The method of  claim 1 , wherein plating the gapfill metal is accomplished by localized proximity head electrochemical plating. 
     
     
         4 . The method of  claim 1 , wherein chemically or electrochemically deplating the portion of overburden metal is accomplished with a localized proximity head. 
     
     
         5 . The method of  claim 1 , wherein electrochemically deplating the portion of overburden metal is accomplished by localized proximity head electrochemical etching. 
     
     
         6 . The method of  claim 1 , wherein electrochemically deplating the portion of overburden metal is accomplished by localized proximity head electrochemical etching with deionized water contacting the overburden metal, a negatively biased electrolyte solution, and a cation transfer membrane separating the deionized water from the electrolyte solution so that cations formed from the gapfill metal are conveyed from the deionized water to the electrolyte solution. 
     
     
         7 . The method of  claim 1 , further comprising rinsing and drying the overburden metal before electrochemically deplating the portion of overburden metal. 
     
     
         8 . The method of  claim 1 , further comprising translating the wafer during plating and deplating. 
     
     
         9 . The method of  claim 1 , wherein plating the gapfill metal is accomplished by localized proximity head electrochemical plating using a first proximity head to confine a volume of electrochemical plating fluid within an area beneath the first proximity head, the area being less than an entirety of the wafer surface. 
     
     
         10 . The method of  claim 1 , wherein electrochemically deplating the portion of overburden metal is accomplished by localized proximity head electrochemical etching using a second proximity head to confine a volume of electrochemical deplating fluid within an area beneath the second proximity head, the area being less than an entirety of the wafer surface. 
     
     
         11 . The method of  claim 1 , further comprising rinsing and drying the overburden metal before electrochemically deplating the portion of overburden metal, the rinsing and the drying being accomplished using localized proximity head rinsing and drying using a third proximity head to confine a volume of rinsing fluid within an area beneath the third proximity head, the area being less than an entirety of the wafer surface. 
     
     
         12 . A method of processing a wafer having holes for through-hole vias for three-dimensional integrated circuits comprising:
 providing a process chamber for holding the wafer;   providing a proximity head integrated with the process chamber, the proximity head being configured to accomplish wet chemical processing of the wafer;   using the proximity head to electrochemically plate a gapfill metal layer to at least partially fill the holes on the wafer while holding the wafer in the process chamber;   using the proximity head to electrochemically deplate a portion of the thickness of the overburden metal for the gapfill metal layer, and   moving the wafer to a chemical mechanical planarization chamber before complete removal of the overburden metal and using chemical mechanical planarization to planarize the gapfill metal and to remove the remaining overburden metal.   
     
     
         13 . A method of processing a wafer having holes for integrated circuits, the method being performed with an integrated system having:
 a process chamber for containing the wafer;   a plating component integrated with the process chamber, the plating component being configured to electrochemically plate a gapfill metal layer onto the wafer to substantially fill the holes; and   a deplating component integrated with the process chamber, the deplating component being configured to chemically or electrochemically remove a portion of overburden metal formed by the plating component;   
       the method comprising performing multiple scans of the wafer with the plating component and the deplating component until the holes are substantially filled and the desired amount of thickness of the overburden metal is removed, wherein each scan adds a portion of the gapfill metal to fill the holes and each scan removes a portion of the thickness of the overburden metal.