Copper electrolytic process using cation permeable barrier

Abstract

Processes and systems for electrolytically processing a microfeature workpiece with a first processing fluid and an anode are described. Microfeature workpieces are electrolytically processed using a first processing fluid, an anode, a second processing fluid, and a cation permeable barrier layer. The cation permeable barrier layer separates the first processing fluid from the second processing fluid while allowing certain cationic species to transfer between the two fluids. The described processes produce deposits over repeated plating cycles that exhibit deposit properties (e.g., resistivity) within desired ranges.

1 . A process for electrolytically processing a microfeature workpiece as the working electrode with a first processing fluid and a counter electrode comprising: 
 contacting a surface of the microfeature workpiece with the first processing fluid, the first processing fluid comprising first processing fluid species including a copper ion, an anion, and a complexing agent;    contacting the counter electrode with a second processing fluid;    producing an electrochemical reaction at the counter electrode; and    substantially preventing movement of anionic species between the first processing fluid and the second processing fluid species.    
   
   
       2 . The process of  claim 1 , wherein the step of substantially preventing movement of anionic species between the first processing fluid and the second processing fluid comprises providing a cation permeable barrier between the first processing fluid and the second processing fluid.  
   
   
       3 . The process of  claim 2 , wherein the cation permeable barrier is a cation exchange membrane.  
   
   
       4 . The process of  claim 1 , wherein the working electrode is a cathode, and the counter electrode is an anode.  
   
   
       5 . The process of  claim 4 , further comprising the step of electrolytically depositing the copper ion onto the surface of the microfeature workpiece.  
   
   
       6 . The process of  claim 4 , wherein the first processing fluid further comprises hydrogen ion and the hydrogen ion passes between the first processing fluid and the second processing fluid through the cation exchange membrane.  
   
   
       7 . The process of  claim 4 , wherein the anode is an inert anode.  
   
   
       8 . The process of  claim 4 , wherein the anode is a consumable anode.  
   
   
       9 . The process of  claim 3 , further comprising the step of passing the copper ion between the first processing fluid and the second processing fluid through the cation exchange membrane.  
   
   
       10 . The process of  claim 1 , wherein the first processing fluid has a pH less than 7.0.  
   
   
       11 . The process of  claim 1 , wherein the second processing fluid has a pH less greater than 7.0.  
   
   
       12 . The process of  claim 1 , wherein the concentration of the copper ion in the first processing fluid is greater than the concentration of copper ion in the second processing fluid.  
   
   
       13 . The process of  claim 1 , wherein the complexing agent is selected from the group consisting of ethylene diamine, ethylene diamine tetraacetic acid and its salts, cyclam, porphrin, bipyridyl, pyrolle, thiophene, and polyamines.  
   
   
       14 . The process of  claim 1 , wherein the complexing agent is selected from compounds that contain a nitrogen-containing chelating group R—NR 2 —R 1 , where R is any alkyl group, aromatic group, or polymer chain and R 1  and R 2  are H, alkyl or aryl organic groups.  
   
   
       15 . The process of  claim 1 , wherein the complexing agent includes chemical compounds having at least one part with the chemical structure COOR 1 —COHR 2 R 3  where R 1  is an organic group or hydrogen covalently bound to the carboxylate group (COO), R 2  is either hydrogen or an organic group, and R 3  is either hydrogen or an organic group.  
   
   
       16 . The process of  claim 1 , wherein pH of the first processing fluid is substantially equal to pH of the second processing fluid.  
   
   
       17 . The process of  claim 1 , further comprising the step of depositing copper ion onto the surface of the microelectronic workpiece.  
   
   
       18 . The process of  claim 5 , wherein the surface onto which copper ion is deposited comprises a seed material.  
   
   
       19 . The process of  claim 5 , wherein the surface onto which copper ion is deposited comprises a barrier material.  
   
   
       20 . A process for electrolytically processing a microfeature workpiece with a first processing fluid and an inert anode comprising: 
 contacting a surface of the microfeature workpiece with the first processing fluid, the first processing fluid including a copper ion to be deposited onto the surface of the microfeature workpiece, a counter anion to the copper ion, and a complexing agent;    contacting the inert anode with a second processing fluid including hydrogen, a cation permeable barrier located between the first processing fluid and the second processing fluid;    producing an oxidizing agent at the inert anode;    adding a copper ion to the first processing fluid;    passing hydrogen ions from the second processing fluid to the first processing fluid through the cation permeable barrier; and    depositing copper ion onto the surface of the microelectronic workpiece.    
   
   
       21 . A process for electrolytically processing a microfeature workpiece with a first processing fluid and an inert anode comprising: 
 contacting a surface of the microfeature workpiece with the first processing fluid, the first processing fluid comprising first processing fluid species including a copper ion to be deposited onto the surface of the microelectronic workpiece; and    contacting the inert anode with a second processing fluid that includes a buffer and a pH adjustment agent, a cation permeable barrier located between the first processing fluid and the second processing fluid.    
   
   
       22 . The process of  claim 21  wherein the buffer is boric acid.  
   
   
       23 . The process of  claim 21  wherein the pH adjustment agent is tetramethylammonium hydroxide.  
   
   
       24 . A system for electrolytically processing a microfeature workpiece with a first processing fluid comprising: 
 a chamber including:    a processing unit for receiving the first processing fluid;    a counter electrode unit for receiving a second processing fluid;    an counter electrode in the counter electrode unit;    a cation permeable barrier between the processing unit and the counter electrode unit;    a source of complexing agent;    a source of a copper ion in fluid communication with the processing unit or the counter electrode unit; and    a source of a pH adjustment agent in fluid communication with the processing unit or the counter electrode unit.    
   
   
       25 . The process of  claim 1 , wherein the counter electrode comprises multiple electrodes.  
   
   
       26 . The process of  claim 1 , wherein the working electrode comprises multiple electrodes.  
   
   
       27 . The process of  claim 1 , wherein the working electrode is an anode, and the counter electrode is a cathode.  
   
   
       28 . The process of  claim 27 , wherein the first processing fluid comprises a copper ion and a counter anion for the copper ion, and further comprising electrolytic dissolution of copper on the surface of the microfeature workpiece.  
   
   
       29 . The process of  claim 27 , wherein the cathode is an inert electrode in contact with the second processing fluid.  
   
   
       30 . The process of  claim 29 , wherein pH of the first processing fluid is less than pH of the second processing fluid  
   
   
       31 . The process of  claim 30 , wherein reduction of chemical species in the second processing fluid occurs at the cathode.  
   
   
       32 . The process of  claim 29 , wherein pH of the first processing fluid is greater than pH of the second processing fluid.  
   
   
       33 . The process of  claim 27 , wherein the first processing fluid has a pH greater than 7.0.  
   
   
       34 . The process of  claim 27 , further comprising the step of adding a pH adjustment agent to the second processing fluid.  
   
   
       35 . The process of  claim 1 , further comprising the step of electrolytically dissolving copper from the surface of the microfeature workpiece.  
   
   
       36 . A process for electrolytically processing a microfeature workpiece with a first processing fluid and cathode comprising: 
 contacting a surface of the microfeature workpiece with the first processing fluid, the first processing fluid including hydrogen ion;    contacting the cathode with a second processing fluid containing hydrogen ion, a cation permeable barrier located between the first processing fluid and the second processing fluid;    producing a reducing agent at the cathode;    adding pH adjustment agent to the second processing fluid;    passing hydrogen ion from the first processing fluid to the second processing fluid through the cation permeable barrier; and    electrolytically dissolving copper from the surface of the microfeature workpiece.