High Purity Copper and Method of Producing High Purity Copper Based on Electrolysis

Abstract

High purity copper having a purity of 6N or higher, wherein content of each of the respective components of P, S, 0, and C is 1 ppm or less, and nonmetal inclusions having a particle size of 0.5 μm or more and 20 μm or less contained in the copper are 10,000 inclusions/g or less. As a result of using high purity copper or high purity copper alloy as the raw material from which harmful P, S, C, 0-based inclusions have been reduced and controlling the existence form of nonmetal inclusions, it is possible to reduce the occurrence of rupture of a bonding wire and improve the reproducibility of mechanical properties, or reduce the percent defect of a semiconductor device wiring formed by sputtering a high purity copper target with favorable reproducibility.

1 . High purity copper having a purity of 6N or higher, wherein content of each of the respective components of P, S, O, and C is 1 ppm or less, and nonmetal inclusions having a particle size of 0.5 μm or more and 20 μm or less contained in the copper are 10,000 inclusions/g or less. 
     
     
         2 . The high purity copper according to  claim 1 , wherein inclusions of carbon or carbide having a particle size of 0.5 μm or more and 20 μm or less are 5,000 inclusions/g or less. 
     
     
         3 . A method of producing high purity copper based on electrolysis, wherein electrolysis is performed by providing a partition between a cathode and an anode, and, upon supplying electrolyte extracted from an electrolytic cell on the anode side or additional electrolyte to an electrolytic cell on the cathode side, passing the electrolyte through an activated carbon filter immediately before supplying it to the electrolytic cell on the cathode side, and thereafter supplying the electrolyte to the electrolytic cell on the cathode side. 
     
     
         4 . The method of producing high purity copper based on electrolysis according to  claim 3 , wherein a purity of 6N or higher, content of each of the respective components of P, S, O, and C being 1 ppm or less, and nonmetal inclusions having a particle size of 0.5 μm or more and 20 μm or less contained in the .copper being 10,000 inclusions/g or less are achieved based on electrolysis. 
     
     
         5 . The method of producing high purity copper based on electrolysis. according to  claim 3 , wherein inclusions of carbon or carbide having a particle size of 0.5 μm or more and 20 μm or less contained in the copper are made to be 5,000 inclusions/g or less.