Patent ID: 7974097

Claim:
A heat sink for a printed circuit board, the printed circuit board comprising a through opening for accommodating melted lead-free tin, the heat sink comprising at least one soldering portion, the soldering portion being immersed into the through opening for guiding the melted lead-free tin upwardly along a surface of the soldering portion, the heat sink being characterized in that the soldering portion comprises a sheet-shaped body and a protruding structure protruding from the sheet-shaped body, wherein a contact area of the protruding structure for the melted lead-free tin is smaller than that of the sheet-shaped body so as to reduce heat conduction effect between the soldering portion and the melted lead-free tin, the protruding structure being capable of guiding the melted lead-free tin upwardly along a lateral contact surface of the protruding structure and the sheet-shaped body in a lateral direction; wherein the protruding structure is formed as a triangular tooth, a gap between two adjacent triangular teeth is formed as a reversed triangular recess, and a size of the reversed triangular recess is similar to that of the triangular tooth.