Patent Application
20060141675
The present invention relates to a method of manufacturing a heat spreader having a vapor chamber defined therein. The heat spreader can be suitably applied to remove heat from heat-generating components.
It is common knowledge that heat is produced during normal operations of a variety of electronic components, such as integrated circuit chips of computers. To ensure normal and safe operations, cooling devices such as heat sinks are often employed to dissipate the generated heat away from these electronic components. However, as the chips of computers decrease in size and increase in power, the heat sinks required to cool the chips have grown to have a much larger footprint than the chips. Generally, a heat sink is most effective when there is a uniform heat flux applied over an entire base of the heat sink. When a heat sink with a large base is attached to an integrated circuit chip with a much smaller contact area, there is significant resistance to the flow of heat to the other portions of the heat sink base which are not in direct contact with the chip.
Currently, an advantageous mechanism for overcoming the resistance to heat flow in a heat sink base is to attach a heat spreader to the base of the heat sink. A typical heat spreader includes a vacuum vessel defining therein a vapor chamber, and a working fluid contained in the chamber of the vessel. In most cases, a wick structure is provided inside the chamber, lining the inside walls of the vessel. As an integrated circuit chip is maintained in thermal contact with and transfers heat to the heat spreader, the working fluid contained in the chamber corresponding to the hot contacting location vaporizes into vapor. The vapor runs quickly to be full of the chamber, and wherever the vapor comes into contact with a cooler wall surface of the vessel, it will condense into liquid and release its latent heat of vaporization. The condensed liquid then returns back to the hot contacting location via capillary action of the wick structure, to thereby remove the heat generated by the chip. In the chamber of the heat spreader, the thermal resistance associated with the vapor spreading is negligible, thus providing an effective means of spreading the heat from a concentrated source to a large heat transfer surface.
Although the heat spreader has low thermal resistance to the flow of heat, the immaturity in manufacture of such a heat spreader has already become a limitation to its application in electronic industry for dissipating heat from electronic components. Soldering process is a typical method currently available for manufacturing a vapor chamber-based heat spreader. The soldering process requires two or more pieces of metal plate to be soldered together. However, the heat spreader made by this method is sometimes a little heavier than expected, since, according to the soldering requirements thereof, each piece of metal plate to be soldered in the soldering process is required to have a minimum wall thickness, which, in some cases, is larger than that is normally required. In addition, the reliability of the heat spreader made by the soldering process is also a problem. If the heat spreader is not hermetically sealed due to a defective soldering, it will gradually lose vacuum condition in the vapor chamber subject to a micro-leakage. Moreover, the soldering process basically cannot make a heat spreader with relatively complex structure.
In view of the above-mentioned disadvantages of the conventional soldering process, there is a need for a method which can manufacture a vapor-chamber-based heat spreader while overcoming these disadvantages.
The present invention relates to a method for manufacturing a heat spreader having a vapor chamber defined therein. A preferred method of the present invention includes the following steps: (1) providing a mold, the mold having a surface; (2) electrodepositing a layer of metal coating on the surface of the mold; (3) removing the mold from the coating layer, wherein the coating layer defines therein a chamber corresponding to the mold; (4) filling a working fluid into the chamber of the coating layer via a hole of the coating layer and sealing the hole of the coating layer, to thereby form a vapor chamber-based heat spreader.
According to the preferred method of the present invention, the heat spreader is integrally made by electrodeposition, and therefore the weight of the heat spreader can be easily controlled into an acceptable range by controlling the thickness of the coating layer. By providing different molds, heat spreaders with different structures can be accordingly obtained. Further, the reliability of the heat spreader made by the preferred method is also improved since the heat spreader is integrally formed.
Other advantages and novel features of the present invention will become more apparent from the following detailed description of preferred embodiments when taken in conjunction with the accompanying drawings, in which:
With reference to
Then, the mold 30 is disposed into an electrodeposition bath 40 which contains an electrolyte 42, as shown in
The coating layer 34, together with the mold 30 contained therein, is then taken out of the electrodeposition bath 40. The mold 30 is removed away from the coating layer 34 via its outlet holes 341 formed by the posts by, fox example, applying mechanical vibration thereto to thereby disintegrate the mold 30 into particles, whereby the mold 30 can be dumped out of the coating layer 34, as shown in
After the mold 30 is completely removed, a semi-product comprised of the coating layer 34 is therefore obtained, as shown in
In accordance with the present invention, the filling material 20 is selected from such materials that can be easily removed after the coating layer 34 is electrodeposited on the mold 30. Therefore, the filling material 20 can also be plastic or polymeric material that is sensitive to temperature. In this situation, the mold 30 is made typically by filling the plastic or polymeric material into the container 10 when it is at a molten state. The material solidifies in the container 10 when it is cooled. Similarly, with respect to the mold-removing step 300, heating the coating layer 34 and the mold 30 above the melting temperature of the filling material 20 is an effective way to remove the filling material 20 away from the coating layer 34.
Another embodiment in accordance with the present invention for making a vapor chamber-based heat spreader is shown in
According to the preferred method of the present invention, a heat spreader can be integrally made by electrodepositing, and the weight of the heat spreader can be easily controlled into an acceptable range since the wall thickness of the coating layer can be easily controlled by regulating the time period and voltage of the electrodeposition. By using different molds on which the coating layer is formed, heat spreaders with different structures can accordingly be obtained, even with some having relatively complex structures. Compared with the conventional soldering method, the reliability of the heat spreader made by the preferred method of the present invention is also improved since the heat spreader is integrally made and accordingly the micro-leakage problem is eliminated.
It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
| Number | Date | Country | Kind |
|---|---|---|---|
| 093140458 | Dec 2004 | TW | national |
