Electrolytic copper plating method, pure copper anode for electrolytic copper plating, and semiconductor wafer having low particle adhesion plated with said method and anode
View Patent ↗The present invention pertains to an electrolytic copper plating method characterized in employing pure copper as the anode upon performing electrolytic copper plating, and performing electrolytic copper plating with the pure copper anode having a crystal grain diameter of 10 μm or less or 60 μm or more. Provided are an electrolytic copper plating method and a pure copper anode for electrolytic copper plating used in such electrolytic copper plating method capable of suppressing the generation of particles such as sludge produced on the anode side within the plating bath upon performing electrolytic copper plating, and capable of preventing the adhesion of particles to a semiconductor wafer, as well as a semiconductor wafer plated with the foregoing method and anode having low particle adhesion.
1. An assembly for performing electrolytic copper plating, comprising a plating bath containing a copper sulfate plating liquid and an anode and cathode submerged in said plating liquid within said plating bath, said anode comprising a copper anode having a purity, crystal grain diameter, and oxygen content that enables said copper anode to inhibit generation of sludge during electroplating, said crystal grain diameter being from 100 μm to 2000 μm and said purity of said copper anode being 3N (99.9 wt %) to 6N (99.9999 wt %), excluding gas components.
2. An assembly according to claim 1 , wherein said crystal grain diameter of said copper anode is 100 μm to 500 μm.
3. An assembly according to claim 2 , wherein said cathode is a semiconductor wafer.
4. An assembly according to claim 3 , wherein said purity of said copper anode is 4N (99.99 wt %) to 5N (99.999 wt %), excluding gas components.
5. An assembly according to claim 3 , wherein said oxygen content of said copper anode is less than 10 ppm.
6. An assembly according to claim 3 , wherein said oxygen content of said copper anode is 1000 to 10,000 ppm.
7. An assembly according to claim 6 , wherein said oxygen content of said copper anode is 4000 ppm.
8. An electrolytic copper plating method comprising the steps of employing pure copper as an anode for performing electrolytic copper plating, and performing electrolytic copper plating with said pure copper anode, said anode having a crystal grain diameter of less than 10 μm or 60 μm or more.
9. An electrolytic copper plating method according to claim 8 , wherein said crystal grain diameter of said pure copper anode is 5 μm or less.
10. An electrolytic copper plating method according to claim 8 , wherein said crystal grain diameter of said pure copper anode is 100 μm to 2000 μm.
11. An electrolytic copper plating method according to claim 8 , wherein said crystal grain diameter of said pure copper anode is 100 μm to 500 μm.
12. An electrolytic copper plating method according to claim 8 , wherein said pure copper of said anode has a purity of 3N (99.9 wt %) to 6N (99.9999 wt %), excluding gas components.
13. An electrolytic copper plating method according to claim 12 , wherein said pure copper of said anode has an oxygen content of 500 to 15,000 ppm.
14. An electrolytic copper plating method according to claim 12 , wherein said pure copper of said anode has an oxygen content of 1,000 to 10,000 ppm.
15. An electrolytic copper plating method according to claim 8 , wherein said electrolytic copper plating is performed on a semiconductor wafer.
16. A semiconductor wafer having low particle adhesion produced by a process comprising the steps of inhibiting generation of sludge during electrolytic copper plating by employing copper as an anode for performing electrolytic copper plating, and performing electrolytic copper plating with said copper anode on a semiconductor wafer, said anode having a crystal grain diameter of 5 μm or less or 100 μm to 2000 μm.
17. A semiconductor wafer according to claim 16 , wherein said crystal grain diameter of said copper anode is 5 μm or less or 100 μm to 500 μm.