Investigation of the low resistivity Cu wire formation in the 8 inch wafer using ultra-high purity plating materials

We have confirmed the effectiveness of ultra-high purity plating material on the formation of low resistivity Cu wires for 22 nm level ULSIs using 8 inch wafer. The resistivity of the 30 nm wide Cu wires formed by ultra-high purity process is found to be 30% lower than those for Cu wires fabricated by the conventional process. It was also found that the grain size of the ultra-high purity processed Cu wires is larger than that of the conventional processed Cu wires by 30%, and the grain size is much more uniform. This innovative new process is expected to be one of the powerful candidates as the Cu wire forming process for 22 nm level ULSIs.