Rigid-flexible printed circuit board and method of manufacturing the same

Abstract

The present invention relates to a rigid-flexible printed circuit board and, more particularly, to a rigid-flexible printed circuit board including CL via holes which can facilitate electrical connection to an inner circuit pattern in a flexible region. Since the coverlays are layered on the entire surface of the double-sided FCCL without previous processing thereof, the via holes are formed in the coverlays while a drilling process is performed to form the via holes, and then the copper plating is performed over the entire surface thereof, it is possible to eliminate the cost of previously processing the coverlays, easily perform a process of provisionally layering the coverlays on the double-sided FCCL, and decrease the cost therefor.

1 . A rigid-flexible printed circuit board comprising a rigid region and a flexible region, wherein the flexible region comprises:
 at least one double-sided flexible copper foil laminate;   coverlays respectively layered on copper foil layers of the flexible copper foil laminate, and provided with windows having predetermined diameters; and   plating layers respectively formed in the windows, the plating layers comprising additional plating portions that have diameters respectively larger than predetermined diameters of the windows and are formed on portions of the coverlays adjacent to the windows.   
   
   
       2 . The rigid-flexible printed circuit board as set forth in  claim 1 , wherein a blind via hole having a diameter smaller than the predetermined diameter of each of the windows is formed in the flexible region to correspond to each of the windows. 
   
   
       3 . The rigid-flexible printed circuit board as set forth in  claim 1 , wherein an inner via hole which has a diameter smaller than the predetermined diameter of each of the windows, and through which the upper and lower portions of the flexible copper foil laminate are electrically connected, is formed in the flexible region to correspond to each of the windows. 
   
   
       4 . The rigid-flexible printed circuit board as set forth in  claim 1 , wherein the least one flexible copper foil laminate is at least two flexible copper coil laminates layered in the flexible region, and the windows are formed in outermost copper foil layers of the layered flexible copper foil laminates. 
   
   
       5 . A method of manufacturing a rigid-flexible printed circuit board, comprising the steps of:
 (A) providing a base substrate in which coverlays are respectively formed on two sides of a flexible copper foil laminate on both sides of which inner circuit patterns are respectively formed;   (B) layering insulation layers and copper foil layers on portions of coverlays which are to be a rigid region of the flexible copper foil laminate;   (C) forming a via hole in the rigid region, and, simultaneously, forming first windows in the coverlays in a flexible region;   (D) forming outer circuit patterns including areas adjacent to the first windows; and   (E) applying solder resist in the rigid region to expose portions of the external circuit patterns;   wherein the outer circuit patterns formed in the areas adjacent to the first windows include additional plating portions for covering portions of the coverlays.   
   
   
       6 . The method as set forth in  claim 5 , wherein, at step (C), the via hole formed in the rigid region and the first windows formed in the flexible region are formed using a CO 2  laser. 
   
   
       7 . The method as set forth in  claim 5 , after step (B), further comprising the steps of:
 (B-1) forming a through hole in the rigid region through a drilling process; and   (B-2) forming a second window in a copper foil in the rigid region.   
   
   
       8 . The method as set forth in  claim 7 , wherein a via hole is formed in the rigid region to correspond to the second window. 
   
   
       9 . The method as set forth in  claim 5 , after step (E), further comprising:
 (E-1) applying conductive paste to form ground shield layers on outer sides of the flexible region.   
   
   
       10 . A method of manufacturing a rigid-flexible printed circuit board, comprising the steps of:
 (A) providing a base substrate in which coverlays are respectively formed on two sides of a flexible copper foil laminate on both sides of which inner circuit patterns and a first window are respectively formed;   (B) layering insulation layers and copper foil layers on portions of coverlays which are to be a rigid region of the base substrate;   (C) forming a via hole in the rigid region, and, simultaneously, forming a via hole to correspond to the first window in a flexible region;   (D) forming outer circuit patterns including areas adjacent to the first window; and   (E) applying solder resists in the rigid region to expose portions of external circuit patterns,   wherein the region adjacent to the via holes in the flexible region includes additional plating portions for covering the coverlays.   
   
   
       11 . The method as set forth in  claim 10 , wherein, at step (C), the via hole formed in the rigid region and the via hole formed in the flexible region are formed using a CO 2  laser. 
   
   
       12 . The method as set forth in  claim 10 , wherein diameters of the additional plating portions are larger than distances between the coverlays corresponding to the additional plating layers, and the distances between the coverlays are larger than a diameter of the first window. 
   
   
       13 . The method as set forth in  claim 10 , wherein the via hole formed in the flexible region is a blind via hole. 
   
   
       14 . The method as set forth in  claim 10 , wherein the via hole formed in the flexible region is an inner via hole. 
   
   
       15 . The method as set forth in  claim 10 , further comprising, after the step (B):
 (B-1) forming a second window in a copper foil in the rigid region.   
   
   
       16 . The method as set forth in  claim 15 , wherein a via hole is formed in the rigid region to correspond to the second window. 
   
   
       17 . A method of manufacturing a rigid-flexible printed circuit board, comprising the steps of:
 (A) providing a base substrate in which coverlays are respectively formed on two sides of a flexible copper foil laminate, on both sides of which inner circuit patterns are respectively formed;   (B) layering insulation layers and copper foil layers on the portions of coverlays which are to be a rigid region of the flexible copper foil laminate;   (C) forming a via hole in the rigid region, and simultaneously forming a via hole in one spot of a flexible region;   (D) forming outer circuit patterns including areas adjacent to a via hole window; and   (E) applying solder resists in the rigid region to expose portions of the external circuit patterns,   wherein the region adjacent to the via holes in the flexible region includes additional plating portions for covering the coverlays.   
   
   
       18 . The method as set forth in  claim 17 , wherein, at the step (C), the via hole formed in the rigid region and the via hole formed in the flexible region are formed using an ultraviolet laser. 
   
   
       19 . The method as set forth in  claim 17 , wherein, at the step (C), the via hole formed in the flexible region is a blind via hole. 
   
   
       20 . The method as set forth in  claim 17 , wherein, at the step (C), the via hole formed in the flexible region is an inner via hole.