Printed circuit board with embedded capacitors therein, and process for manufacturing the same

Abstract

Disclosed herein is a printed circuit board with embedded capacitors therein which comprises inner via holes filled with a high dielectric polymer capacitor paste composed of a composite of BaTiO 3 and an epoxy resin, and a process for manufacturing the printed circuit board.

1 . A process for manufacturing a printed circuit board with embedded capacitors therein, comprising the steps of:
 i) forming a plurality of inner via holes on predetermined regions of a non-copper clad laminate;   ii) filling the via holes with a capacitor paste;   iii) providing copper foil layers on both upper and lower surfaces of the capacitor paste, respectively;   iv) forming predetermined dry film patterns on the copper foil layers;   v) exposing to light and developing the dry film patterns to form top electrodes, bottom electrodes and signal circuit patterns;   vi) laminating resin coated copper (RCC) layers to the top electrodes, the bottom electrodes and the signal circuit patterns;   vii) forming predetermined outer via holes and through-holes in the resin coated copper layers; and   viii) plating the inner walls of the outer via holes and the through-holes.   
   
   
       2 . The process for manufacturing a printed circuit board with embedded capacitors therein according to  claim 1 , wherein the non-copper clad laminate is an FR-4 insulator. 
   
   
       3 . The process for manufacturing a printed circuit board with embedded capacitors therein according to  claim 1 , further comprising the step of drying to cure the filled capacitor paste. 
   
   
       4 . The process for manufacturing a printed circuit board with embedded capacitors therein according to  claim 3 , wherein the capacitor paste is dried in an oven drier at 150˜170° C. for 30 minutes. 
   
   
       5 . The process for manufacturing a printed circuit board with embedded capacitors therein according to  claim 3 , further comprising the step of polishing to smooth overfilled capacitor paste so as to adjust the cured capacitor paste to a uniform height. 
   
   
       6 . The process for manufacturing a printed circuit board with embedded capacitors therein according to  claim 5 , wherein the capacitor paste is smoothed using a ceramic buff. 
   
   
       7 . The process for manufacturing a printed circuit board with embedded capacitors therein according to  claim 1 , wherein the via holes are filled with the capacitor paste using a screen-printing manner. 
   
   
       8 . The process for manufacturing a printed circuit board with embedded capacitors therein according to  claim 1 , wherein the capacitor paste is a composite of high dielectric BaTiO 3  ceramic powders having a dielectric constant of 1,000˜10,000 and a thermosetting epoxy resin or polyimide. 
   
   
       9 . The process for manufacturing a printed circuit board with embedded capacitors therein according to  claim 1 , wherein the capacitor paste is a polymer ceramic composite having a dielectric constant of about 80˜90, the polymer ceramic composite being obtained by homogeneously dispersing the BaTiO 3  powders composed of coarse powders having a particle diameter of 0.9 μm and fine powders having a particle diameter of 60 nm (bimodal form) in the epoxy resin in a volume ratio of 3:1˜5:1. 
   
   
       10 . The process for manufacturing a printed circuit board with embedded capacitors therein according to  claim 1 , wherein the copper foil layers are subjected to electroless plating or electro plating. 
   
   
       11 . The process for manufacturing a printed circuit board with embedded capacitors therein according to  claim 1 , wherein the resin coated copper (RCC) layers are laminated by a build-up process. 
   
   
       12 . The process for manufacturing a printed circuit board with embedded capacitors therein according to  claim 1 , wherein the via holes are formed using a laser drill. 
   
   
       13 . The process for manufacturing a printed circuit board with embedded capacitors therein according to  claim 1 , wherein the through-holes are formed using a mechanical drill. 
   
   
       14 . The process for manufacturing a printed circuit board with embedded capacitors therein according to  claim 1 , wherein the outer via holes and the through-holes are subjected to electroless plating.