Printed circuit board and method of manufacturing the same

Abstract

Disclosed is a printed circuit board including bumps formed using a conductive paste including carbon nanotubes and a photosensitive binder. A method of manufacturing the printed circuit board is also provided. The printed circuit board includes bumps formed using the conductive paste having carbon nanotubes, and can realize good electrical connection with electronic parts mounted thereon. The bumps can be formed at a fine pitch, thus realizing a circuit layer having a high density.

1 . A printed circuit board, comprising:
 a circuit substrate having a circuit layer for transferring electrical signals; and   bumps electrically connected to the circuit layer and formed of a conductive paste including carbon nanotubes and a photosensitive binder.   
     
     
         2 . The printed circuit board as set forth in  claim 1 , wherein the circuit substrate further comprises external connection terminals exposed in an outermost circuit layer thereof, and the bumps are formed on the external connection terminals. 
     
     
         3 . The printed circuit board as set forth in  claim 1 , wherein the bumps have a stepped cylindrical shape. 
     
     
         4 . The printed circuit board as set forth in  claim 1 , wherein the conductive paste further comprises metal powder. 
     
     
         5 . The printed circuit board as set forth in  claim 1 , wherein the photosensitive binder is any one selected from among acrylic resin, styrene resin, novolac epoxy resin, and polyester resin. 
     
     
         6 . A method of manufacturing a printed circuit board, comprising:
 applying a conductive paste including carbon nanotubes and a photosensitive binder on a bump-forming area of a circuit substrate having a circuit layer for transferring electrical signals; and   patterning the conductive paste, thus forming bumps.   
     
     
         7 . The method as set forth in  claim 6 , wherein the conductive paste further comprises metal powder. 
     
     
         8 . The method as set forth in  claim 6 , wherein the circuit substrate further comprises external connection terminals exposed in an outermost circuit layer thereof, and the bump-forming area comprises an area in which the external connection terminals are exposed. 
     
     
         9 . The method as set forth in  claim 6 , wherein the forming the bumps comprises:
 disposing a mask having light-blocking patterns for forming the bumps on the conductive paste; and   radiating light onto the mask, thus selectively exposing the conductive paste to light, and then developing the conductive paste.   
     
     
         10 . The method as set forth in  claim 9 , wherein the forming the bumps further comprises drying the bumps, after the radiating light. 
     
     
         11 . The method as set forth in  claim 9 , wherein the mask is a glass mask. 
     
     
         12 . The method as set forth in  claim 9 , wherein the developing in the radiating light is conducted using any one developer selected from among Na2CO3, KCO3, and KOH.