Printed circuit board and method for making the same

A printed circuit board, comprising:

• a substrate having a plurality of through holes;
• a plurality of thermally-conductive blocks, disposed in the plurality of through holes respectively;
• a first upper metal circuit layer, formed on a top surface of the substrate;
• and
• a first lower metal circuit layer, formed on a bottom surface of the substrate;
• wherein each of said thermally-conductive block is attached to at least one inner wall of said through hole through a bonding structure comprising a metal block and a metal layer coated on two side surfaces of the metal block, respectively.

A method for making a printed circuit board, comprising following steps:

• forming a plurality of through holes in a substrate;
• respectively disposing a thermally-conductive block in each said through hole;
• applying a sputtering process to the substrate, so as to coat a top surface and two side surfaces of said thermally-conductive block, a top surface of the substrate, and at least one inner wall of said through hole with a sputtered metal layer, respectively;
• applying an electroplating process to the substrate, such that each said through hole is filled with an electroplated metal member, and the top surface of the substrate is further coated with a first electroplated metal layer;
• applying a thickness reducing process to the first electroplated metal layer;
• and
• patterning the first electroplated metal layer to form a first upper metal circuit layer through a photolithography process, such that a bonding structure is formed in each said through hole;
• wherein the bonding structure comprises the electroplated metal member and the sputtered metal layer coated on the inner wall of the through hole, and said thermally-conductive block is tightly attached to the inner wall of the through hole through said bonding structure.