Method and apparatus for filling interconnect structures

Abstract

Methods, apparatus, and systems for depositing copper and other metals are provided. In some implementations, a wafer substrate is provided to an apparatus. The wafer substrate has a surface with field regions and a feature. A copper layer is plated onto the surface of the wafer substrate. The copper layer is annealed to redistribute copper from regions of the wafer substrate to the feature. Implementations of the disclosed methods, apparatus, and systems allow for void-free bottom-up fill of features in a wafer substrate.

What is claimed is: 
     
         1 . An apparatus comprising:
 a plating chamber configured to hold an electrolyte;   a work piece holder configured to hold a work piece in the plating chamber, the work piece including a surface having edge regions; and   an element including an ionically resistive body with perforations in the body such that the perforations do not form communicating channels within the body, wherein the perforations allow for transport of the electrolyte through the element, wherein the element is positioned to have a surface facing the surface of the work piece, wherein the apparatus is configured such that the surface of the element is located within about 10 millimeters from said surface of the work piece during plating, wherein substantially all the perforations have a principal dimension of an opening on the surface of the element facing the surface of the work piece of no greater than about 5 millimeters, and wherein the porosity of the element is about 1 to 3%.   
     
     
         2 . The apparatus of  claim 1 , wherein the resistance in the volume occupied by the element is about 25 to 250 ohms; and wherein the apparatus further comprises a power supply capable of providing an output voltage of at least about 50 V. 
     
     
         3 . The apparatus as recited in  claim 1 , wherein the porosity of the element corresponds to the area occupied by the openings of the perforations on the surface of the element divided by an area occupied by the surface of the element. 
     
     
         4 . The apparatus as recited in  claim 1 , wherein the element has a thickness in a direction normal to the surface of the work piece when the work piece is held by the work piece holder, and wherein the thickness of the element is about 5 to 50 millimeters. 
     
     
         5 . The apparatus as recited in  claim 1 , wherein a resistance of the element is about 0.04 to 0.4 ohms per square centimeter of the surface of the element. 
     
     
         6 . The apparatus as recited in  claim 1 , wherein the element surface is substantially coextensive with the work piece surface. 
     
     
         7 . The apparatus as recited in  claim 1 , wherein the element has a diameter of about 150 to 450 millimeters. 
     
     
         8 . The apparatus as recited in  claim 1 , wherein the element comprises a disk having about 5,000 to 12,000 perforations. 
     
     
         9 . The apparatus as recited in  claim 1 , wherein the element includes a non-uniform distribution of perforations in a central region of the element, and wherein the element includes a uniform distribution of perforations in a peripheral region of the element 
     
     
         10 . The apparatus as recited in  claim 1 , further comprising:
 one or more electrical contacts configured to make an electrical connection to the surface of the work piece at one or more locations on edge regions of the surface; and   a power supply in operable communication with the electrical contacts, an anode, and a controller.   
     
     
         11 . The apparatus as recited in  claim 1 , further comprising:
 a shield positioned between the element and the work piece to block a path between at least some of the perforations in a peripheral region of the element and the work piece.   
     
     
         12 . The apparatus as recited in  claim 1 , further comprising a second cathode configured for diverting a portion of an ionic current from the edge regions of the work piece. 
     
     
         13 . The apparatus as recited in  claim 12 , wherein the second cathode is contained in a second chamber on the outside of the plating chamber, and wherein the second chamber is in ionic communication with the plating chamber. 
     
     
         14 . The apparatus as recited in  claim 1 , further comprising:
 a controller configured to control plating operations to plate a metal onto the work piece.   
     
     
         15 . The apparatus as recited in  claim 1 , further comprising:
 a spin rinse dryer configured to rinse the electrolyte from the work piece and to dry the work piece.   
     
     
         16 . The apparatus as recited in  claim 15 , wherein the spin rinse dryer is further configured to anneal the work piece. 
     
     
         17 . The apparatus as recited in  claim 1 , further comprising:
 an annealing chamber configured to anneal the work piece.   
     
     
         18 . A system comprising the apparatus of  claim 1  and a stepper. 
     
     
         19 . An apparatus comprising:
 a plating chamber configured to hold an electrolyte;   a work piece holder configured to hold a work piece in the plating chamber, the work piece including a surface having edge regions;   an element including an ionically resistive body with perforations in the body such that the perforations do not form communicating channels within the body, wherein the perforations allow for transport of the electrolyte through the element, wherein the element is positioned to have a surface facing the surface of the work piece, wherein the apparatus is configured so that the surface of the element is located within about 10 millimeters from said surface of the work piece during plating, wherein substantially all the perforations have a principal dimension of an opening on the surface of the element facing the surface of the work piece of no greater than about 5 millimeters, and wherein the porosity of the element is about 1 to 3%; and   a cathode configured to divert a portion of an ionic current from the edge regions of the work piece.   
     
     
         20 . The apparatus of  claim 19 , wherein the resistance in the volume occupied by the element is about 25 to 250 ohms; and wherein the apparatus further comprises a power supply capable of providing an output voltage of at least about 50 V. 
     
     
         21 . An apparatus comprising:
 a plating chamber configured to hold an electrolyte;   a work piece holder configured to hold a work piece in the plating chamber, the work piece including a surface having edge regions;   an element including an ionically resistive body with perforations in the body such that the perforations do not form communicating channels within the body, wherein the perforations allow for transport of the electrolyte through the element, wherein the element is positioned to have a surface facing the surface of the work piece, wherein the apparatus is configured so that the surface of the element is located within about 10 millimeters from said surface of the work piece during plating, wherein substantially all the perforations have a principal dimension of an opening on the surface of the element facing the surface of the work piece of no greater than about 5 millimeters, and wherein the porosity of the element is about 1 to 3%; and   a shield positioned between the element and the work piece to block a path between at least some of the perforations in a peripheral region of the element and the work piece.   
     
     
         22 . The apparatus of  claim 21 , wherein the resistance in the volume occupied by the element is about 25 to 250 ohms; and wherein the apparatus further comprises a power supply capable of providing an output voltage of at least about 50 V.