Printed circuit board

Abstract

A printed circuit board includes a base layer, a first conductive pattern, and a first surface treatment patterned layer formed on a portion of a surface of the first conductive pattern. The first conductive pattern includes a first copper foil layer on one side of the base layer and a first conductive layer on a portion of a surface of the first copper foil layer. The first conductive pattern which is covered by the first surface treatment patterned layer has sidewalls obliquely tilted with respect to the base layer. The first conductive pattern covered with the first surface treatment patterned layer has a cross section that is trapezoidal shaped, and a width which gradually decreases from the base layer to the first conductive layer.

What is claimed is: 
     
         1 . A printed circuit board comprising:
 a base layer;   a first conductive pattern comprising:
 a first copper foil layer formed on one side of the base layer; and 
 a first conductive layer formed on a portion of a surface of the first copper foil layer; and 
   a first surface treatment patterned layer formed on a portion of a surface of the first conductive pattern,   wherein the first conductive pattern which is covered with the first surface treatment patterned layer has sidewalls tilted with respect to the base layer at an oblique angle, the first conductive pattern covered with the first surface treatment patterned layer having a cross section that is trapezoidal shaped, and a width gradually decreasing in a direction from the base layer to the first conductive layer.   
     
     
         2 . The printed circuit board of  claim 1 , wherein a thickness of the first conductive layer is greater than a thickness of the first copper foil layer. 
     
     
         3 . The printed circuit board of  claim 1 , wherein a thickness of the first conductive pattern covered with the first surface treatment patterned layer is greater than a thickness of the first conductive pattern that is not covered with the first surface treatment patterned layer. 
     
     
         4 . The printed circuit board of  claim 1 , wherein the first surface treatment patterned layer is made of nickel-gold (Ni—Au), nickel-platinum-gold (Ni—Pt—Au), or nickel-palladium-gold (Ni—Pd—Au). 
     
     
         5 . The printed circuit board of  claim 1 , wherein the printed circuit board further comprises a first solder mask layer, the first solder mask layer covers the surface of the first conductive pattern, which is not covered with the first surface treatment patterned layer, and part of the surfaces of the first surface treatment patterned layer and the base layer at the same side, and the first surface treatment patterned layer exposed from the first solder mask layer becomes a first connective portion. 
     
     
         6 . The printed circuit board of  claim 5 , wherein the first connective portion is a bonding pad or a conductive finger. 
     
     
         7 . The printed circuit board of  claim 1 , wherein the printed circuit board further comprises:
 a second conductive pattern formed on another side of the base layer, and the second conductive pattern is opposite to the first conductive pattern, the second conductive pattern comprises:   a second copper foil layer, the second copper foil layer is opposite to the first copper foil layer; and   a second conductive layer formed on a portion of a surface of the second foil layer; and   a second surface treatment patterned layer formed on a portion of a surface of the second conductive pattern; and   a through hole covered with a third conductive layer to be formed as a conductive through hole for connecting the first conductive pattern and the second conductive pattern,   wherein the second conductive pattern which is covered with the second surface treatment patterned layer has sidewalls tilted with respect to the base layer at an oblique angle, the second conductive pattern covered with the second surface treatment patterned layer having a cross section that is trapezoidal shaped, and a width gradually decreased in a direction from the base layer to the second conductive layer.   
     
     
         8 . The printed circuit board of  claim 7 , wherein a thickness of the second conductive pattern which is covered with the second surface treatment patterned layer is greater than a thickness of the second conductive pattern which is not covered with the second surface treatment patterned layer. 
     
     
         9 . The printed circuit board of  claim 7 , wherein the printed circuit board further comprises a seed layer, the seed layer is positioned on the surfaces of the first copper foil layer, the second copper foil layer, and on the wall of the through hole, and the seed layer is positioned under the first conductive layer, the second conductive layer, and the third conductive layer. 
     
     
         10 . The printed circuit board of  claim 9 , wherein a thickness of the second conductive layer is greater than a sum of thicknesses of the second copper foil layer and the seed layer positioned on the second copper foil layer.