Nano-copper via fill for enhanced thermal conductivity of plated through-hole via
View Patent ↗A process of constructing a filled via of a printed circuit board comprises drilling a via hole through a body of the printed circuit board, desmearing a barrel of the via hole, metallizing a outer surface of the via barrel, electroplating the via barrel, pushing nano-copper solder into the via hole and heating the circuit board in order to melt the nano-copper solder within the via hole. The nano-copper solder improves the thermal conductivity of the printed circuit board for applications when heat needs to be conducted from one side of the printed circuit board to another.
1. A printed circuit board comprising:
a. a printed circuit board body; and
b. one or more electroplated via holes passing through the body,
wherein each via hole comprises a nano-copper solder deposited within the via by pushing the nano-copper solder from one side of the via and pulling the nano-copper solder from an opposite side of the via, wherein the circuit board is heated to approximately 200° C. such that the nano-copper solder is melted, and wherein the melting point of the nano-copper solder is greater than 200° C. after it resolidifies.
2. The printed circuit board of claim 1 , wherein a barrel of each via hole is metallized using an electroless copper plating solution.
3. The printed circuit board of claim 2 , wherein copper is electroplated into the via barrel.
4. The printed circuit board of claim 1 , further comprising an electroplated copper capping layer.
5. The printed circuit board of claim 1 , wherein the nano-copper solder comprises more than one particle size.