Electrolytic process using cation permeable barrier
View Patent ↗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 metal cation, an anion, and a complexing agent wherein the complexing agent is selected from the group consisting of 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, and a complexing agent that 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;
contacting the counter electrode with a second processing fluid;
producing an electrochemical reaction at the counter electrode;
electrolytically depositing the metal cation onto the surface of the microfeature workpiece; and
substantially preventing movement of anionic and complexing agent species between the first processing fluid and the second processing fluid.
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 , 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.
6. The process of claim 4 , wherein the anode is an inert anode.
7. The process of claim 4 , wherein the anode is a consumable anode.
8. The process of claim 3 , further comprising the step of passing the metal cation between the first processing fluid and the second processing fluid through the cation exchange membrane.
9. The process of claim 1 , wherein the first processing fluid has a pH less than 7.0.
10. The process of claim 1 , wherein the second processing fluid has a pH less greater than 7.0.
11. The process of claim 1 , wherein the concentration of the cation in the first processing fluid is greater than the concentration of the cation in the second processing fluid.
12. 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.
13. The process of claim 1 , wherein pH of the first processing fluid is substantially equal to pH of the second processing fluid.
14. The process of claim 1 , further comprising the step of depositing the cation onto the surface of the microelectronic workpiece.
15. The process of claim 1 , wherein the surface onto which the cation is deposited comprises a seed material.
16. The process of claim 1 , wherein the surface onto which the cation is deposited comprises a barrier material.
17. The process of claim 1 , wherein the cation is selected from the group consisting of copper ion, lead ion, gold ion, tin ion, silver ion, platinum ion, ruthenium ion, rhodium ion, iridium ion, osmium ion, rhenium ion, palladium ion, and nickel ion.
18. The process of claim 1 , wherein the counter electrode comprises multiple electrodes.
19. The process of claim 1 , wherein the working electrode comprises multiple electrodes.
20. The process of claim 1 , wherein the working electrode is an anode, and the counter electrode is a cathode.
21. The process of claim 20 , wherein the first processing fluid comprises a cation and an anion, and further comprising electrolytic dissolution of metal on the surface of the microfeature workpiece.
22. The process of claim 20 , wherein the cathode is an inert electrode in contact with the second processing fluid.
23. The process of claim 22 , wherein pH of the first processing fluid is less than pH of the second processing fluid.
24. The process of claim 23 , wherein reduction of chemical species in the second processing fluid occurs at the cathode.
25. The process of claim 22 , wherein pH of he first processing fluid is greater than pH of the second processing fluid.
26. The process of claim 20 , wherein the first processing fluid has a pH Greater than 7.0.
27. The process of claim 20 , wherein the cation is a metal cation.
28. The process of claim 20 , further comprising the step of adding a pH adjustment agent to the second processing fluid.
29. The process of claim 1 , further comprising the step of electrolytically dissolving metal from the surface of the microfeature workpiece.
30. 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 metal cation, an anion, and a complexing agent, wherein the complexing agent is selected from the group consisting of 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, and a complexing agent that 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;
contacting the counter electrode with a second processing fluid;
producing an electrochemical reaction at the counter electrode;
electrolytically depositing the metal cation onto the surface of the microfeature workpiece; and
providing a cation exchange membrane to substantially prevent movement of anionic and complexing agent species between the first processing fluid and the second processing fluid and to substantially prevent fluid movement across the cation ion exchange membrane.
31. The process of claim 30 , wherein the first processing fluid species include at least one organic component selected from the group consisting of accerators, suppressors, and levelers, and wherein the cation exchange membrane substantially prevents movement of the at least one organic component between the first processing fluid and the second processing fluid.
32. The process of claim 1 , wherein the metal cation concentration in the first processing fluid is in the range of 0.03 to 0.25 M.
33. The process of claim 1 , further comprising substantially preventing the formation of an oxidiziding agent at the counter electrode.
34. The process of claim 1 , further comprising preventing gases generated at the counter electrode from passing into the first processing fluid.
35. The process of claim 1 , wherein the ratio between the concentration of the copper ion and the concentration of the complexing agent is in the range from 1:25 to 25:1.
36. The process of claim 1 , wherein the first processing fluid further includes a buffering agent having a concentration in the range of about 0.0001 M to about 0.5 M.
37. The process of claim 1 , wherein the of the first processing fluid is in the range of about 7 to about 13.
38. 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 metal cation, an anion, and a complexing agent;
contacting the counter electrode with a second processing fluid;
producing an electrochemical reaction at the counter electrode;
electrolytically depositing the metal cation onto the surface of the microfeature workpiece; and
providing a cation permeable barrier between the first processing fluid and the second processing fluid to substantially prevent the movement of anionic and complexing agent species between the first processing fluid and the second processing fluid, wherein the cation permeable barrier is oriented in a substantially horizontal orientation.