Electroplating on ultra-thin seed layers

Abstract

Methods and structures for the electroplating on ultra-thin seed layers are disclosed. A dual layer structure is utilized, consisting of a thicker, highly conductive layer surrounding device structures. Within the device die, an ultra-thin seed layer is employed, which is electrically coupled to the conduction layer. Using this technique, electroplating of critical device structures can be carefully controlled and made uniform across the full diameter of the wafer. The technique also allow for the deployment of ultra-thin seed layers of varying thickness and composition in different locations within the circuit device, or in different die on the wafer.

1 . A method for electroplating device structures, comprising:
 vapor depositing a seed layer on a first portion of a wafer surface;   vapor depositing a conduction layer on a second portion of said wafer surface, wherein said conduction layer is electrically coupled to said seed layer; and,   electroplating a device structure on said seed layer by conducting electrical current through said conduction layer to said seed layer.   
     
     
         2 . The method as recited in  claim 1 , wherein said seed layer is less than 25 nm thick. 
     
     
         3 . The method as recited in  claim 2 , wherein said seed layer comprises a noble metal. 
     
     
         4 . The method as recited in  claim 2 , wherein said seed layer comprises at least one of Ni, Fe, Co, and Cr. 
     
     
         5 . The method as recited in  claim 2 , wherein said seed layer comprises Ta. 
     
     
         6 . The method as recited in  claim 2 , wherein said seed layer comprises a plurality of layers. 
     
     
         7 . The method as recited in  claim 1 , wherein said conduction layer is greater than 20 nm in thickness. 
     
     
         8 . The method as recited in  claim 7 , wherein said conduction layer comprises a noble metal. 
     
     
         9 . The method as recited in  claim 7 , wherein said conduction layer comprises at least one of Cu and Al. 
     
     
         10 . The method as recited in  claim 7 , wherein said conduction layer comprises a plurality of layers. 
     
     
         11 . The method as recited in  claim 1 , wherein vapor deposition of said conduction layer comprises sputtering said conduction layer. 
     
     
         12 . A method for electroplating device structures, comprising:
 vapor depositing a first seed layer on a first portion of a wafer surface;   vapor depositing a second seed layer on a second portion of said wafer surface;   vapor depositing a conduction layer on a third portion of said wafer surface, wherein said conduction layer is electrically coupled to said first and said second seed layers;   electroplating a first device structure on said first seed layer by conducting electrical current through said conduction layer to said first seed layer; and,   electroplating a second device structure on said second seed layer by conducting electrical current through said conduction layer to said second seed layer.   
     
     
         13 . The method as recited in  claim 12 , wherein said first seed layer and said second seed layer are less than 25 nm thick. 
     
     
         14 . The method as recited in  claim 13 , wherein said first seed layer and said second seed layer comprise different materials. 
     
     
         15 . The method as recited in  claim 13 , wherein said first seed layer and said second seed layer comprise a noble metal. 
     
     
         16 . The method as recited in  claim 13 , wherein said first seed layer and said second seed layer comprise at least one of Ni, Fe, Co, and Cr. 
     
     
         17 . The method as recited in  claim 13 , wherein said first seed layer and said second seed layer comprise Ta. 
     
     
         18 . The method as recited in  claim 13 , wherein said first seed layer and said second seed layer comprise a plurality of layers. 
     
     
         19 . The method as recited in  claim 12 , wherein said conduction layer is greater than 20 nm in thickness. 
     
     
         20 . The method as recited in  claim 19 , wherein said conduction layer comprises a noble metal. 
     
     
         21 . The method as recited in  claim 19 , wherein said conduction layer comprises at least one of Cu and Al. 
     
     
         22 . The method as recited in  claim 19 , wherein said conduction layer comprises a plurality of layers. 
     
     
         23 . The method as recited in  claim 12 , wherein vapor deposition of said conduction layer comprises sputtering said conduction layer. 
     
     
         24 . A method for electroplating device structures, comprising:
 vapor depositing a seed layer on a wafer surface;   vapor depositing a conduction layer on a first portion of said seed layer; and,   electroplating a device structure on a second portion of said seed layer by conducting electrical current through said conduction layer to said second portion of said seed layer.   
     
     
         25 . The method as recited in  claim 24 , wherein said seed layer is less than 25 nm thick. 
     
     
         26 . The method as recited in  claim 25 , wherein said seed layer comprises a noble metal. 
     
     
         27 . The method as recited in  claim 25 , wherein said seed layer comprises at least one of Ni, Fe, Co, and Cr. 
     
     
         28 . The method as recited in  claim 25 , wherein said seed layer comprises Ta. 
     
     
         29 . The method as recited in  claim 25 , wherein said seed layer comprises a plurality of layers. 
     
     
         30 . The method as recited in  claim 24 , wherein said conduction layer is greater than 20 nm in thickness. 
     
     
         31 . The method as recited in  claim 30 , wherein said conduction layer comprises a noble metal. 
     
     
         32 . The method as recited in  claim 30 , wherein said conduction layer comprises at least one of Cu and Al. 
     
     
         33 . The method as recited in  claim 30 , wherein said conduction layer comprises a plurality of layers. 
     
     
         34 . The method as recited in  claim 24 , wherein vapor deposition of said conduction layer comprises sputtering said conduction layer. 
     
     
         35 . A method for electroplating device structures, comprising:
 vapor depositing a conduction layer on a first portion of a wafer surface;   vapor depositing a seed layer on a second portion of said wafer surface, and on at least a portion of said conduction layer; and,   electroplating a device structure on said seed layer covering said second portion of said wafer surface, by conducting electrical current through said conduction layer to at least a portion of said seed layer.   
     
     
         36 . The method as recited in  claim 35 , wherein said seed layer is less than 25 nm thick. 
     
     
         37 . The method as recited in  claim 36 , wherein said seed layer comprises a noble metal. 
     
     
         38 . The method as recited in  claim 36 , wherein said seed layer comprises at least one of Ni, Fe, Co, and Cr. 
     
     
         39 . The method as recited in  claim 36 , wherein said seed layer comprises Ta. 
     
     
         40 . The method as recited in  claim 36 , wherein said seed layer comprises a plurality of layers. 
     
     
         41 . The method as recited in  claim 35 , wherein said conduction layer is greater than 20 nm in thickness. 
     
     
         42 . The method as recited in  claim 41 , wherein said conduction layer comprises a noble metal. 
     
     
         43 . The method as recited in  claim 41 , wherein said conduction layer comprises at least one of Cu and Al. 
     
     
         44 . The method as recited in  claim 41 , wherein said conduction layer comprises a plurality of layers. 
     
     
         45 . The method as recited in  claim 35 , wherein vapor deposition of said conduction layer comprises sputtering said conduction layer.