Copper filling-up method

Abstract

There is provided a method of well filling copper in a conductivity-rendered non-through hole having an aspect ratio (depth/hole diameter) of 5 or more on a substrate in a short period of time, and the method comprises using an acidic copper plating bath comprising a water-soluble copper salt, sulfuric acid, chlorine ion, a brightener and a copolymer of diallylamines and sulfur dioxide and filling copper in the non-through hole by periodic current reversal copper plating.

1 . A method of filling copper in a conductivity-rendered non-through hole having an aspect ratio (depth/hole diameter) of 5 or more on a substrate, the method comprising carrying out periodic current reversal copper plating with an acidic copper plating bath to fill copper in the non-through hole, the acidic copper plating bath comprising a water-soluble copper salt, sulfuric acid, chlorine ion, a brightener and a copolymer of diallylamines and sulfur dioxide, the copolymer containing a diallylamine constituent unit of the general formula, 
       
         
           
           
               
               
           
         
         wherein each of R 1  and R 2  is independently a hydrogen atom or an alkyl group having 1 or 2 carbon atoms, and X −  is a counter ion, 
       
       and a sulfur dioxide constituent unit of the formula (II), 
       
         
           
           
               
               
           
         
       
     
     
         2 . The method of filling copper as recited in  claim 1 , wherein the acidic copper plating bath further contains a carrier. 
     
     
         3 . The method of filling copper as recited in  claim 1 , wherein the substrate is a substrate comprising a silicon layer. 
     
     
         4 . The method of filling copper as recited  claim 1 , wherein the substrate is a substrate that is micro-contact-printing-treated in advance. 
     
     
         5 . The method of filling copper as recited in  claim 1 , wherein a current density during positive electrolysis in the periodic current reversal copper plating is 3.5 mA/cm 2  or more. 
     
     
         6 . The method of filling copper as recited in  claim 5 , wherein a current density during reverse electrolysis in the periodic current reversal copper plating is 1 to 5 times the current density during the positive electrolysis. 
     
     
         7 . The method of filling copper as recited in  claim 1 , wherein the periodic current reversal plating is set to be repeated in the order of positive electrolysis and reverse electrolysis or in the order of positive electrolysis, reverse electrolysis and a pause, the positive electrolysis is set to take a time period of 1 to 1,000 msec., the reverse electrolysis is set to take a time period of 1/100 to ⅕ times the time period of the positive electrolysis, and the pause is set to take a time period 0 to 3 times the time period of the positive electrolysis.