Electrolytic copper plating method, phosphorus-containing anode for electrolytic copper plating, and semiconductor wafer plated using them and having few particles adhering to it
View Patent ↗The present invention pertains to an electrolytic copper plating method characterized in employing a phosphorous copper anode having a crystal grain size of 1500 μm (or more) to 20000 μm in an electrolytic copper plating method employing a phosphorous copper anode. Upon performing electrolytic copper plating, an object is to provide an electrolytic copper plating method of a semiconductor wafer for preventing the adhesion of particles, which arise at the anode side in the plating bath, to the plating object such as a semiconductor wafer, a phosphorous copper anode for electrolytic copper plating, and a semiconductor wafer having low particle adhesion plated with such method and anode.
1. A method of electrolytic copper plating a semiconductor wafer, comprising the steps of:
placing the semiconductor wafer within a plating bath containing a copper sulfate plating liquid;
electrolytic copper plating the semiconductor wafer in the plating bath employing a phosphorous copper anode having a crystal grain size of 1,500 μm to 20,000 μm; and
during said plating step, producing sludge from said anode having as a principle component metallic copper of a relative density such that it does not float within the plating bath thereby preventing particles from reaching the semiconductor wafer, adhering to the semiconductor wafer, and causing inferior plating.
2. A method according to claim 1 , wherein said plating step includes forming copper wiring on the semiconductor wafer.
3. A method according to claim 1 , further comprising the step of adjusting or optimizing the crystal grain size of the phosphorous copper anode to 1,500 μm to 20,000 μm before said plating step.
4. A method according to claim 1 , wherein phosphorous content of the phosphorous copper anode is 50 to 2,000 wtppm.
5. A method according to claim 1 , wherein phosphorous content of the phosphorous copper anode is 100 to 1,000 wtppm.
6. A method according to claim 1 , wherein said crystal grain size of said phosphorous copper anode is 1,500 μm to 5,000 μm during said plating.
7. A method according to claim 1 , wherein said crystal grain size of said phosphorous copper anode is 1,800 μm to 5,000 μm during said plating.
8. A method according to claim 1 , wherein said crystal grain size of said phosphorous copper anode is 18,000 μm to 20,000 μm during said plating.