Highly pure copper anode for electrolytic copper plating, method for manufacturing same, and electrolytic copper plating method

Abstract

Provided are a highly pure copper anode for electrolytic copper plating, a method for manufacturing the same, and an electrolytic copper plating method using the highly pure copper anode. The highly pure copper anode obtains a crystal grain boundary structure having a special grain boundary ratio Lσ N /L N of 0.35 or more. L N is a unit total special grain boundary length. Lσ N is a unit total special boundary length. By having the configuration described above, plating defect can be reduced by suppressing the occurrence of the particles, such as the slime or the like, which are generated on the anode side in the plating bath.

1 . A highly pure copper anode for electrolytic copper plating comprising a grain boundary structure satisfying the following relationship:
 Lσ N /L N ≧0.35, wherein   (a) a total crystal grain boundary length L within a measurement area being measured with a scanning electron microscope by irradiating an electron beam to individual crystal grains on a surface of the anode under a condition that an interface between crystal grains laying side-by-side having a mutual crystal orientation difference of 15° or more is defined as the crystal grain boundary, and a unit total crystal grain boundary length L N  being a converted value corresponding to a unit area of 1 mm 2  from the total crystal grain boundary length L;   (b) locations of special crystal grain boundaries, where a special grain boundary is formed between an interface between crystal grains laying side-by-side, being determined, a total special crystal grain boundary length Lσ of the special crystal grain boundaries being measured with a scanning electron microscope by irradiating an electron beam to individual crystal grains on the surface of the anode, and a unit total special crystal grain boundary length Lσ N  being a converted value corresponding to a unit area of 1 mm 2  from the total special crystal grain boundary length Lσ; and   (c) Lσ N /L N  being a ratio of Lσ N , which is the measured unit total special crystal grain boundary length, to L N , which is the measured unit total crystal grain boundary length.   
     
     
         2 . The highly pure copper anode for electrolytic copper plating according to  claim 1 , wherein the average diameter of crystal grain is 3 μm to 1000 μm. 
     
     
         3 . A method for manufacturing the highly pure copper anode for electrolytic copper plating according to  claim 1  comprising the steps of:
 imparting machining stress by machining the highly pure copper anode for electrolytic copper plating; and 
 performing recrystallization heat treatment at 250° C. to 900° C. after the step of imparting machining stress, wherein 
 the special grain boundary length ratio Lσ N /L N  is 0.35 or more. 
 
     
     
         4 . The method for manufacturing the highly pure copper anode for electrolytic copper plating according to  claim 3 , wherein the machining is carried out by either cold working or hot working at least. 
     
     
         5 . The method for manufacturing the highly pure copper anode for electrolytic copper plating according to  claim 3 , wherein a process having the cold working and the recrystallization heat treatment, a process having the hot working and the recrystallization heat treatment, or a combination of the two processes is carried out repeatedly until the special grain boundary length ratio Lσ N /L N  becomes 0.35 or more. 
     
     
         6 . The method for manufacturing the highly pure copper anode for electrolytic copper plating according to  claim 4 , wherein a process having the cold working and the recrystallization heat treatment, a process having the hot working and the recrystallization heat treatment, or a combination of the two processes is carried out repeatedly until the special grain boundary length ratio Lσ N /L N  becomes 0.35 or more. 
     
     
         7 . The method for manufacturing the highly pure copper anode for electrolytic copper plating according to  claim 3 , wherein
 the step of imparting machining stress is carried out by hot working at a rolling reduction of 5% to 80% within a temperature range of 350° C. to 900° C., and the step of performing recrystallization heat treatment is carried out by statically holding the highly pure copper anode for 3 to 300 seconds free of imparting the machining stress after the step of imparting machining stress.   
     
     
         8 . The method for manufacturing the highly pure copper anode for electrolytic copper plating according to  claim 3 , wherein
 the step of imparting machining stress is carried out by cold working at a rolling reduction of 5% to 80%, and   the step of performing recrystallization heat treatment is carried out by heating the anode within a temperature range of 250° C. to 900° C. and statically holding the highly pure copper anode for 5 minutes to 5 hours free of imparting the machining stress after the step of imparting machining stress.   
     
     
         9 . An electrolytic copper plating method wherein the highly pure copper anode for electrolytic copper plating according to  claim 1  is used. 
     
     
         10 . A method for manufacturing the highly pure copper anode for electrolytic copper plating according to  claim 2  comprising the steps of:
 imparting machining stress by machining the highly pure copper anode for electrolytic copper plating; and 
 performing recrystallization heat treatment at 250° C. to 900° C. after the step of imparting machining stress, wherein 
 the special grain boundary length ratio Lσ N /L N  is 0.35 or more. 
 
     
     
         11 . The method for manufacturing the highly pure copper anode for electrolytic copper plating according to  claim 10 , wherein the machining is carried out by either cold working or hot working at least. 
     
     
         12 . The method for manufacturing the highly pure copper anode for electrolytic copper plating according to  claim 10 , wherein a process having the cold working and the recrystallization heat treatment, a process having the hot working and the recrystallization heat treatment, or a combination of the two processes is carried out repeatedly until the special grain boundary length ratio Lσ N /L N  becomes 0.35 or more. 
     
     
         13 . The method for manufacturing the highly pure copper anode for electrolytic copper plating according to  claim 11 , wherein a process having the cold working and the recrystallization heat treatment, a process having the hot working and the recrystallization heat treatment, or a combination of the two processes is carried out repeatedly until the special grain boundary length ratio Lσ N /L N  becomes 0.35 or more. 
     
     
         14 . The method for manufacturing the highly pure copper anode for electrolytic copper plating according to  claim 10 , wherein
 the step of imparting machining stress is carried out by hot working at a rolling reduction of 5% to 80% within a temperature range of 350° C. to 900° C., and   the step of performing recrystallization heat treatment is carried out by statically holding the highly pure copper anode for 3 to 300 seconds free of imparting the machining stress after the step of imparting machining stress.   
     
     
         15 . The method for manufacturing the highly pure copper anode for electrolytic copper plating according to  claim 10 , wherein
 the step of imparting machining stress is carried out by cold working at a rolling reduction of 5% to 80%, and   the step of performing recrystallization heat treatment is carried out by heating the anode within a temperature range of 250° C. to 900° C. and statically holding the highly pure copper anode for 5 minutes to 5 hours free of imparting the machining stress after the step of imparting machining stress.   
     
     
         16 . An electrolytic copper plating method wherein the highly pure copper anode for electrolytic copper plating according to  claim 2  is used.