1. Field of the Invention
The present invention relates to a heat sink, and more particularly to a heat sink which is used to remove heat from an electronic component. The present invention also relates to a method of manufacturing the heat sink.
2. Description of Related Art
With the advance of integrated circuit (IC) technology, CPUs are made more and more compact and have higher operation speed than old ones. Thereby, a great deal of heat is generated by the up-to-date CPUs. However in current trend, it is desired that the electronic devices have a compact size; that is, they are smaller in size than the old ones, and thus, it is required that the heat dissipating devices of the electronic devices are compact accordingly, meanwhile have powerful heat dissipating ability.
Referring to FIGS. 6-7, a conventional heat sink comprises a substrate 3 and a plurality of heat dissipating fins 4. A plurality of recesses 31 is defined in an upper surface of the substrate 3. A straight, cylindrical side wall (not labeled) surrounds a corresponding recess 31. The substrate 3 defines a cone-shaped groove (not labeled) between every two recesses 31. The heat dissipating fins 4 are placed in the recesses 31. A plurality of punching pins 41 then punch into the grooves so that the walls surrounding the recesses 31 expand, and, thus, the heat dissipating fins 4 are cramped in the recesses 31 tightly. Thereby, the assembly of the heat sink is finished.
The above structure has the following disadvantages: the expansions of the walls surrounding the recesses 31 are difficult to control whereby gaps may be generated between the fins 4 and the substrate 3. In other words, an intimate contact between the fins 4 and the substrate 3 is not always guaranteed. In addition, the lower ends of the fins 4 are straight; thus, contact areas between the substrate 3 and the fins 4 are small. The heat which is generated by the CPUs can not be quickly transferred to the whole fins since the gaps and the small contact areas between the fins 4 and the substrate 3.
Therefore, a solution for enhancing the contact areas between the fins and the substrate of the heat sink and making sure that the fins are securely fastened to the substrate is needed.