Printed circuit boards and the methods of their production

Abstract

It is an object of the present invention to provide a copper electroplating method for a printed circuit board having via-holes, which can reproducibly secure good plated film quality and via-hole filling capacity even when the board includes a resist or the like. The electroplating bath for electroplating of a printed circuit board, containing at least one compound selected from the group consisting of pyridinium, bipyridinium, phenanthrolinium, quinolinium and phenazinium salts in the form of onium with an N-alkyl, N-aralkyl, N-aryl, N-alkylene or N-aralkylene moiety.

What is claimed is:  
     
         1 . A printed circuit board having via-holes plated by a copper electroplating, wherein the via-holes are substantially filled with a copper electroplating using a copper electroplating bath containing at least one compound selected from the group consisting of pyridinium, bipyridinium, phenanthrolinium, quinolinium and phenazinium salts in the form of onium with an N-alkyl, N-aralkyl, N-aryl, N-alkylene or N-aralkylene moiety.  
     
     
         2 . A method for producing a printed circuit board having via-holes plated by a copper electroplating, wherein an electroplating bath used in the copper electroplating contains at least one compound selected from the group consisting of pyridinium, bipyridinium, phenanthrolinium, quinolinium and phenazinium salts in the form of onium with an N-alkyl, N-aralkyl, N-aryl, N-alkylene or N-aralkylene moiety.  
     
     
         3 . An electroplating method which conducts a copper electroplating using an electroplating bath containing at least one compound selected from the group consisting of pyridinium, bipyridinium, phenanthrolinium, quinolinium and phenazinium salts in the form of onium with an N-alkyl, N-aralkyl, N-aryl, N-alkylene or N-aralkylene moiety.  
     
     
         4 . The electroplating method according to  claim 3 , wherein the N-alkyl, N-aralkyl, N-aryl, N-alkylene or N-aralkylene moiety contains sulfonic acid moiety.  
     
     
         5 . The electroplating method according to  claim 3 , wherein the salts have a low molar extinction coefficient of 5000 M −1 cm −1  (M: moles/litter) in a wavelength region of 400 to 700 nm.  
     
     
         6 . A copper electroplating bath used in a copper electroplating which contains at least one compound selected from the group consisting of pyridinium, bipyridinium, phenanthrolinium, quinolinium and phenazinium salts in the form of onium with an N-alkyl, N-aralkyl, N-aryl, N-alkylene or N-aralkylene moiety.  
     
     
         7 . The copper electroplating bath according to  claim 6 , wherein the N-alkyl, N-aralkyl, N-aryl, N-alkylene or N-aralkylene moiety contains sulfonic acid moiety.  
     
     
         8 . The copper electroplating bath according to  claim 6 , wherein the salts have a low molar extinction coefficient of 5000 M −1 cm −1  (M: moles/litter) in a wavelength region of 400 to 700 nm.