Manufacturing Method of High Purity Nickel, High Purity Nickel, Sputtering Target formed from said High Purity Nickel, and Thin Film formed with said Sputtering Target

Abstract

Upon performing electrolysis with a solution containing nickel as the electrolytic solution, anolyte is adjusted to pH 2 to 5; impurities such as iron, cobalt and copper contained in the anolyte are eliminated by combining any one or two or more of the methods among adding an oxidizing agent and precipitating and eliminating the impurities as hydroxide, eliminating the impurities through preliminary electrolysis, or adding Ni foil and eliminating the impurities through displacement reaction; impurities are thereafter further eliminated with a filter; and the impurity-free solution is employed as catholyte to perform the electrolysis. The present invention relates to a simple method of performing electrolytic refining employing a solution containing nickel from nickel raw material containing a substantial amount of impurities, and provides technology on efficiently manufacturing high purity nickel having a purity of 5N (99.999 wt %) or more.

1 . A high purity nickel of at least 5N (99.999 wt %) for use as a sputtering target for forming a thin film, said high purity nickel excluding gas components, in which as impurities O is 30 wtppm or less and C, N, S, P and F are each 10 wtppm or less. 
     
     
         2 . A sputtering target consisting of said high purity nickel according to  claim 1 . 
     
     
         3 . A thin film formed from said high purity nickel sputtering target according to  claim 2 . 
     
     
         4 . A high purity nickel of at least 5N (99.999 wt %) for use as a sputtering target for forming a thin film, said high purity nickel excluding gas components, in which as impurities O is 30 wtppm or less and C, N, S, P and F are each 10 wtppm or less, and being produced by a process wherein, upon separating an electrolytic bath with a diaphragm to define an anode side and a cathode side of the electrolytic bath and performing electrolysis with a solution containing nickel as the electrolytic solution, anolyte existing in the anode side is extracted intermittently or consecutively, and the extracted anolyte is adjusted to pH 2 to 5; impurity iron contained in the extracted anolyte is eliminated by adding an oxidizing agent to the anolyte and precipitating and eliminating said impurity iron as hydroxide; cobalt and copper impurities are eliminated by at least one of performing preliminary electrolysis to the extracted anolyte and performing displacement reaction by adding nickel foil to the extracted anolyte; impurities including precipitated oxides are thereafter eliminated with an activated carbon filter to provide a substantially impurity-free solution; the impurity-free solution is introduced intermittently or consecutively into the cathode side only of the electrolytic bath such that a concentration of iron within the electrolytic solution in the electrolytic bath is 1 mg/L or less; and the impurity-free solution is employed as catholyte to perform said electrolysis, said 5N (99.999 wt %) or higher nickel being obtained without method steps of ionic exchange and solvent extraction. 
     
     
         5 . A sputtering target consisting of said high purity nickel according to  claim 4 . 
     
     
         6 . A thin film formed from said high purity nickel sputtering target according to  claim 5 . 
     
     
         7 . A high purity nickel of at least 5N (99.999 wt %) for use as a sputtering target for forming a thin film, said high purity nickel excluding gas components, in which as impurities O is 30 wtppm or less and C, N, S, P and F are each 10 wtppm or less, and being produced by a process comprising the steps of:
 partitioning an anode and a cathode of an electrolytic bath with a diaphragm to define an anode side and a cathode side of the electrolytic bath, the anode being made of nickel raw material of a purity of at least 3N (99.9 wt %);   performing electrolysis within the electrolytic bath;   extracting anolyte intermittently or consecutively from the anolyte side of the electrolytic bath;   adjusting pH of the extracted anolyte to about 2 to 5;   eliminating impurity iron contained in the extracted anolyte by adding an oxidizing agent to said extracted anolyte and precipitating said impurity iron as hydroxide;   eliminating cobalt and copper impurities by at least one of adding the extracted anolyte to a preliminary electrolytic bath to eliminate cobalt and copper impurities through preliminary electrolysis and adding an Ni foil to the extracted anolyte to eliminate cobalt and copper impurities through displacement reaction;   after said eliminating steps, filtering said extracted anolyte through an activated carbon filter to remove precipitated oxides and provide a substantially impurity-free solution;   adding the impurity-free solution intermittently or consecutively only to the cathode-side of the electrolytic bath;   performing electrolytic refining by using a cathode side solution added with said impurity free solution; and   obtaining, without ionic exchange and solvent extraction refining steps, nickel having a purity of at least 5N (99.999 wt %), excluding gas components, in the form of electrolytic nickel deposited to the cathode.   
     
     
         8 . A sputtering target consisting of said high purity nickel according to  claim 7 . 
     
     
         9 . A thin film formed from said high purity nickel sputtering target according to  claim 8 .