Printed circuit board having embedded resistors and method of manufacturing the same

Abstract

Disclosed herein is a Printed Circuit Board (PCB) having embedded resistors and a method of manufacturing the same, in which contact pads are formed by filling via holes formed on electrode pads with oxidation-resistant conductive material, and resistors are formed on the contact pads. Accordingly, erosion that occurs between the electrode pads and the resistors can be prevented using the contact pads made of oxidation-resistant conductive material, and connections between circuits also can be realized. Furthermore, resistors are formed on a flat plane without any difference in height, attributable to the electrode pads, and thus differences between the resistance values of the built-in resistors can be greatly reduced.

1 . A Printed Circuit Board (PCB) having embedded resistors, comprising:
 (a) a plurality of circuit layers comprising circuit patterns including electrode pads formed on an internal circuit layer;   (b) a plurality of insulating layers located between respective circuit layers;   (c) a plurality of via holes formed in the insulating layers to enable interlayer electrical connections;   (d) contact pads formed by filling the via holes, which are formed on the electrode pads, with oxidation-resistant conductive material; and   (e) resistors connected with the electrode pads, and formed such that ends of each resistor are connected to two respective contact pads, which are spaced apart from each other, at surfaces of the contact pads, which are on an opposite side from surfaces of the contact pads that are in contact with the electrode pads, and thus connected in an identical plane.   
   
   
       2 . The PCB as set forth in  claim 1 , wherein the oxidation-resistant conductive material is Ag paste. 
   
   
       3 . The PCB as set forth in  claim 1 , wherein the resistors are formed through screen printing of resistor material. 
   
   
       4 . The PCB as set forth in  claim 3 , wherein the resistor material is carbon-based paste. 
   
   
       5 . A method of manufacturing a PCB having embedded resistors, the method comprising:
 (a) providing a PCB on which internal layer circuit patterns, including electrode pads, are formed;   (b) layering insulating layers on the PCB;   (c) forming first via holes on the electrode pads and simultaneously forming second via holes at predetermined locations on the internal layer circuit patterns;   (d) forming contact pads for connecting the electrode pads with resistors by filling the first via holes with oxidation-resistant conductive material and flattening the oxidation-resistant conductive material;   (e) forming the resistors so that ends of each resistor are connected to two respective contact pads, which are spaced apart from each other;   (f) forming circuit patterns on the PCB, in which the second via holes are formed; and   (g) layering insulting layers on the PCB obtained at step (f), and forming external layer circuit patterns.   
   
   
       6 . The method as set forth in  claim 5 , wherein the oxidation-resistant conductive material is Ag paste. 
   
   
       7 . The method as set forth in  claim 5 , wherein the filling of the oxidation-resistant conductive material is performed using screen printing. 
   
   
       8 . The method as set forth in  claim 5 , wherein the flattening is performed through a mechanical polishing process, a chemical polishing process, or a chemical mechanical polishing process. 
   
   
       9 . The method as set forth in  claim 5 , wherein the forming the resistors is performed through screen printing of resistor material. 
   
   
       10 . The method as set forth in  claim 9 , wherein the resistor material is carbon-based paste. 
   
   
       11 . The method as set forth in  claim 5 , further comprising performing laser trimming using the circuit patterns, formed at step (f), as pads. 
   
   
       12 . A method of manufacturing a printed circuit board having embedded resistors, the method comprising:
 (a) providing a PCB on which internal layer circuit patterns, including electrode pads, are formed;   (b) layering insulating layers on the PCB;   (c) forming first via holes on the electrode pads;   (d) forming contact pads for connecting the electrode pads with resistors by filling the first via holes with oxidation-resistant conductive material and flattening the oxidation-resistant conductive material;   (e) forming the resistors so that ends of each resistor are connected to two respective contact pads, which are spaced apart from each other;   (f) forming second via holes at predetermined locations on the internal layer circuit patterns;   (g) forming circuit patterns on the PCB, in which the second via holes are formed; and   (h) layering insulting layers on the PCB obtained at step (g), and forming external layer circuit patterns.   
   
   
       13 . The method as set forth in  claim 12 , wherein the oxidation-resistant conductive material is Ag paste. 
   
   
       14 . The method as set forth in  claim 12 , wherein the filling of the oxidation-resistant conductive material is performed using screen printing. 
   
   
       15 . The method as set forth in  claim 12 , wherein the flattening is performed through a mechanical polishing process, a chemical polishing process, or a chemical mechanical polishing process. 
   
   
       16 . The method as set forth in  claim 12 , wherein the forming the resistors is performed through screen printing of resistor material. 
   
   
       17 . The method as set forth in  claim 16 , wherein the resistor material is carbon-based paste. 
   
   
       18 . The method as set forth in  claim 12 , further comprising performing laser trimming using the circuit patterns, formed at step (g), as pads.