Abstract: An improved heat sink is composed of a base member, a cover member, at least one capillary layer, a plurality of hollow columns, a plurality of cooling fins, and a predetermined amount of solder. The base member is provided with an external wall extending upwards and outwards from a peripheral fringe thereof. The cover member is provided with a skirt portion extending downwards and outwards from a peripheral fringe thereof. A vapor chamber is formed between the cover member and the base member. The capillary layer, which is mounted in the vapor chamber, includes at least one plate member and a plurality of convex portions and is spaced apart from the skirt portion at a predetermined distance. The hollow columns are connected with tile cover member and communicate with the vapor chamber. Each of the hollow columns is fitted with a capillary pipe inside.