Methods for barrier interface preparation of copper interconnect

Abstract

A method is provided, including the following method operations: depositing a metallic barrier layer to line a copper interconnect structure by a dry process in an integrated system configured to operate a mixture of dry and wet processes; depositing the functionalization layer over the metallic barrier layer by a wet process in the integrated system; and, depositing the copper layer over the functionalization layer in the copper interconnect structure by a wet process in the integrated system after the functionalization layer is deposited over the metallic barrier layer, wherein the material used for the functionalization layer comprises a complexing group with at least two ends, one end of the complexing group forming a bond with the metallic barrier layer and another end of the complexing group forming a bond with the copper layer.

What is claimed is: 
     
         1 . A method, comprising:
 depositing a metallic barrier layer to line a copper interconnect structure by a dry process in an integrated system configured to operate a mixture of dry and wet processes;   depositing the functionalization layer over the metallic barrier layer by a wet process in the integrated system; and   depositing the copper layer over the functionalization layer in the copper interconnect structure by a wet process in the integrated system after the functionalization layer is deposited over the metallic barrier layer, wherein the material used for the functionalization layer comprises a complexing group with at least two ends, one end of the complexing group forming a bond with the metallic barrier layer and another end of the complexing group forming a bond with the copper layer.   
     
     
         2 . The method of  claim 1 , wherein the integrated system defines a controlled environment to prevent the formation of metallic barrier oxide after deposition of the metallic barrier layer, the controlled environment defined by a vacuum transfer module coupled to one or more dry process chambers and a controlled-ambient transfer module coupled to one or more wet process chambers, the vacuum transfer module and the controlled-ambient transfer module being coupled to each other so as to form a common path for the substrate to directly travel between the vacuum transfer module and the controlled-ambient transfer module. 
     
     
         3 . The method of  claim 2 , further comprising:
 transporting the substrate from the vacuum transfer module to the controlled-ambient transfer module;   wherein the transfer modules transfer the substrate in a dry state from one process chamber to a next process chamber.   
     
     
         4 . The method of  claim 1 , wherein the functionalization layer between the metallic barrier layer and the copper layer assists the deposition of the copper layer and improves adhesion between the metallic barrier layer and the copper layer. 
     
     
         5 . The method of  claim 1 , further comprising:
 cleaning an exposed surface of an underlying metal to the copper interconnect to remove a surface metal oxide of the exposed surface of the underlying metal in the integrated system before depositing the metallic barrier layer, wherein the underlying metal is part of an underlying interconnect electrically connected to the copper interconnect.   
     
     
         6 . The method of  claim 5 , wherein cleaning the exposed surface of the surface metal oxide is accomplished by using one of an Ar sputtering process or a plasma process using a fluorine-containing gas. 
     
     
         7 . The method of  claim 6 , wherein the fluorine-containing gas is NF 3 , CF 4 , or a combination of both. 
     
     
         8 . The method of  claim 1 , further comprising:
 reducing a surface of the metallic barrier layer to make the surface of the metallic barrier layer metal-rich in the integrated system before depositing the functionalization layer.   
     
     
         9 . The method of  claim 8 , wherein reducing the surface of the metallic barrier layer is performed by using a hydrogen-containing plasma. 
     
     
         10 . The method of  claim 1 , wherein the material of the metallic barrier layer is selected from the group consisting of tantalum nitride (TaN), tantalum (Ta), Ruthenium (Ru), titanium (Ti), tungsten (W), zirconium (Zr), hafnium (Hf), molybdenum (Mo), niobium (Nb), vanadium (V), ruthenium (Ru) and chromium (Cr), and a hybrid combination of these materials. 
     
     
         11 . The method of  claim 1 , wherein the complexing group is selected from the group consisting of decanethiol, octadecanethiol, tetraphenylporphines, diphenyl disulfide, aromatic thioacetate, ruthenium (II) tris(2,2, prime-biphyridine)thiol, thiophenol, 4,4 prime-dithiodipyridine, naphthalene disulfide, and bis(2-anthraquinyl)disulfide, 3-mercaptoprophyl trimethoxysilane, γ-methacryloxypropyl triethoxysilane, perfluoroctanoxylprophy-dimethyl silane, alkyltrichlorosilane, oxtadecylsiloxane, octanol, 22-mercapto-1-docosanoic acid, alkanephosphonic acids, octadecanoic acid, diaminododecane, n-phenylpyrrole, and 2,5-dithienylpyrrol triad. 
     
     
         12 . The method of  claim 1 , wherein the copper interconnect is over an underlying interconnect which includes a metal line. 
     
     
         13 . The method of  claim 1 , wherein the copper interconnect is over an underlying interconnect which includes a contact. 
     
     
         14 . The method of  claim 1 , wherein depositing the metallic barrier layer further includes:
 depositing a first metallic barrier layer; and   depositing a second metallic barrier layer.   
     
     
         15 . The method of  claim 14 , wherein the first metallic barrier layer is deposited by an atomic layer deposition (ALD) process and the second metallic barrier layer is deposited by a physical vapor deposition (PVD) process. 
     
     
         16 . The method of  claim 14 , wherein the first metallic barrier layer is deposited by an ALD process and the second metallic barrier layer is deposited by an ALD process. 
     
     
         17 . The method of  claim 1 , further comprising:
 cleaning a surface of the functionalization layer in the integrated system before depositing the copper layer.   
     
     
         18 . The method of clam  1 , wherein the copper layer is a thin copper seed layer selectively deposited by an electroless process. 
     
     
         19 . The method of  claim 18 , wherein a gap-fill copper layer is deposited following the deposition of the thin copper seed layer by an electrochemical plating (ECP) process. 
     
     
         20 . A method, comprising:
 cleaning an exposed surface of an underlying metal to a copper interconnect to remove a surface metal oxide of the exposed surface of the underlying metal in an integrated system configured to operate a mixture of dry and wet processes before depositing a metallic barrier layer, wherein the underlying metal is part of an underlying interconnect electrically connected to the copper interconnect;   depositing the metallic barrier layer to line the copper interconnect structure by a dry process in the integrated system;   reducing a surface of the metallic barrier layer to make the surface of the metallic barrier layer metal-rich in the integrated system before depositing a functionalization layer;   depositing the functionalization layer over the metallic barrier layer by a wet process in the integrated system; and   depositing a copper layer over the functionalization layer in the copper interconnect structure by a wet process in the integrated system after the functionalization layer is deposited over the metallic barrier layer, wherein the material used for the functionalization layer comprises a complexing group with at least two ends, one end of the complexing group forming a bond with the metallic barrier layer and another end of the complexing group forming a bond with copper.