High-current transmitting method utilizing printed circuit board
The present disclosure relates to a structure and a method for filling a via hole formed in a multilayer printed circuit board, and more particularly, to a structure and a method for filling a via hole formed in a multilayer printed circuit board, the structure and method enabling high-current transmission even in a narrow space in such a way that a via hole formed when a typical multilayer printed circuit board is manufactured is first filled with Cu and Ag plating, and the remaining vacant space is completely filled with a solder cream, thereby increasing the amount of conductors.
1. A multilayer printed circuit board each layer of which is printed with a circuit pattern, the multilayer printed circuit board comprising via holes for connecting circuits of each layer, wherein each via hole is a through hole having a pair of open ends, and wherein each via hole comprises:
a plating layer formed on a side wall of the via hole, the plating layer including a Cu plating layer plated with Cu on the side wall of the via hole and an Au plating layer formed on the Cu plating layer; and
a solder cream on the Au plating layer and filled in a vacant surface of the via holes on which the plating layer is formed.
2. The multilayer printed circuit board of claim 1 , wherein the solder cream is reflowed.
3. The multilayer printed circuit board of claim 1 , wherein the Cu plating layer includes:
a first coating of Cu on the insides of the via holes formed by electroless copper plating; and
a second coating of Cu on the insides of the via holes formed by electrical copper plating.
4. A method for manufacturing a multilayer printed circuit board (MLB), comprising:
a copper foil forming step for plating a copper foil on an entire surface of a laminated plate to form a plurality of copper foil laminated plates;
an inner layer circuit printing step for coating the copper foil laminated plates formed in the copper foil laminated plate forming step with a photosensitive dry film and then with a master film on which a circuit is printed to form a circuit through light irradiation and development;
an etching step for removing unnecessary copper foils from surfaces of the copper foil laminated plates on which the printing of inner layer circuit is completed, to form a circuit;
a rest delaminating step for removing the dry film of a circuit portion to complete circuit formation;
a laminating process step for laminating and attaching each copper foil plate in which the circuit formation is completed;
a via hole processing step for forming via holes at positions connecting circuits located on layers different from each other in the laminated plates after the laminating process step;
a via hole plating step for plating the inside of the holes to be electrically connectable after processing the via holes in the via hole processing step;
a solder mask printing process step for applying a solder mask insulating ink to prevent the generation of a bridge of the soldering solder and the oxidation of exposed circuits when surface mounting for mounting components on an uppermost laminated substrate is performed;
a solder cream filling step for filling a vacant space of the via holes filled with plating when surface mounting for mounting components on the laminated plates is performed; and
a step for completely filling the holes filled with the solder cream in the solder cream filling step by performing a reflow of the solder cream.
5. The method of claim 4 , wherein the via hole plating step comprises firstly plating Cu and secondly plating Au.
6. The method of claim 4 , wherein the via hole plating step comprises:
first coating Cu on the insides of the via holes using electroless copper plating; and
second coating Cu on the insides of the via holes using electrical copper plating.