MICRO-CHANNEL HEAT SINK
A micro-channel heat sink comprises an upper cover layer and a cooling layer. The cooling layer comprises at least one inlet fluid tank, a plurality of micro-channels, and at least one outlet fluid tank. The inlet fluid tank can store and deliver the working fluids, and the outlet fluid tank collects the heated working fluid flowing through the plurality of micro-channels. The plurality of micro-channels are disposed between the inlet fluid tank and the outlet fluid tank, wherein the cross sectional area of each of the micro-channels increases along the direction towards the outlet fluid tank.
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- PHOTORESIST AND FORMATION METHOD THEREOF
- PHOTORESIST AND FORMATION METHOD THEREOF
(A) Field of the Invention
The present invention relates to a micro-channel heat sink, and more particularly, to a high performance micro-channel heat sink.
(B) Description of the Related Art
With improvements in micro-scaling technologies for electrical components, various electronic products in recent years have been reduced in size to meet the specifications for portable design. The personal computer, digital camera, PDA, and mobile phone have attained the light weight and compact size required for portability. However, owing to the scaling of the electronic products in design, the issue of cooling for high performance electrical components has also arisen, and the industry has taken notice. Therefore, thermal analysis technologies have become a critical factor affecting how quickly products can be brought to market. According to reports by international electronics magazines, 50% of the causes of malfunctions in electronic products result from inadequately designed cooling systems.
The continuous demand for increasing the circuit density and power of electrical components has resulted in higher heat dissipation per unit area, with up to 100 W of heat dissipation for a single chip. Even though current improvements in the IC manufacturing process lower the heat generated from electrical components, other cooling technologies are still necessary for lowering the temperature of the single chip without degrading its speed and performance. Generally speaking, air-cooling is only applicable to components with thermal dissipation of less than 104 W/m2. Cooling fans and cooling fins are not only bulky but also noisy and inefficient. When the thermal load of the electrical component exceeds 104 W/m2, better cooling methods are required to dissipate the continuously accumulated heat in order to maintain suitable chip operating temperature.
However, traditional cooling technologies are limited by their design, so various cooling devices are currently being developed to replace them. Among the different efforts, developments of the micro-channel heat sink fabricated by MEMS (Micro Electrical Mechanical System) processes are more progressive. Not only can such heat sinks be mass produced to reduce costs, but they also have the merits of light weight, miniaturized size, superior spatial utilization, shorter response time, and high heat dissipation rate. Therefore, they have many potential applications in the future.
Because the two-phase flow and boiling heat transfer within the micro-channels result in high efficiency of thermal dissipation, the micro-channel heat sink is critical for further enhancing the performance of electrical components. Particularly, the silicon micro-channels can be formed on a silicon substrate directly through an etching process. Therefore, the use of high heat transfer cooling fluid within the micro-channels and the large heat transfer areas of the micro-channels can easily remove a large amount of heat, thereby enhancing the performance of the electrical components.
In summary, the market is in urgent need of a cooling device with high stability, high heat transfer capability, and high heat dissipation efficiency so as to stably remove a large amount of heat from the electrical component. Accordingly, the performance of the electrical component is enhanced.
SUMMARY OF THE INVENTIONThe present invention provides a micro-channel heat sink, whose miniaturized structure can prevent the reverse flow of bubbles and pressure oscillations. That is, the bubbles in the boiling fluid cannot easily flow backwards to block the transportation of a working fluid in micro-channels. Therefore, this micro-channel heat sink is a cooling device with high stability, high heat transfer capability, and high power efficiency.
The present invention provides a micro-channel heat sink, comprising an upper cover layer and a cooling layer. The cooling layer comprises at least one inlet fluid tank, a plurality of micro-channels, and at least one outlet fluid tank. The inlet fluid tank can store and deliver a working fluid. The outlet fluid tank collects the heated working fluid flowing through the plurality of micro-channels. The plurality of micro-channels are disposed between the inlet fluid tank and the outlet fluid tank. The cross sectional area of each of the micro-channels increases along the direction from the inlet fluid tank towards the outlet fluid tank.
The objectives and advantages of the present invention will become apparent upon reading the following description and upon reference to the accompanying drawings in which:
The following will demonstrate the present invention using the accompanying drawings to clearly present the characteristics of the technology.
In fact, gradually increasing the cross sectional area of each micro-channel 323 can eliminate the instability phenomenon existing in the two-phase flow of the micro-channels 323. The bubbles resulting from the boiling fluid can smoothly exit the channel, and the early occurrence of the critical value of the heat transfer rate can also be suppressed. So, the micro-channel heat sink 30 can still reliably operate and maintain a high heat transfer capability even under boiling conditions.
The above-described embodiments of the present invention are intended to be illustrative only. Those skilled in the art may devise numerous alternative embodiments without departing from the scope of the following claims.
Claims
1. A micro-channel heat sink, comprising:
- a cooling layer, comprising: at least one inlet fluid tank storing and delivering a working fluid; at least one outlet fluid tank collecting and draining the working fluid; and a plurality of micro-channels disposed between the inlet fluid tank and the outlet fluid tank, wherein the cross sectional area of each of the micro-channels increases along a direction towards the outlet fluid tank; and
- an upper cover layer covering the plurality of micro-channels.
2. The micro-channel heat sink of claim 1, wherein the upper cover layer is an IC chip.
3. The micro-channel heat sink of claim 1, wherein the cross sectional area of the micro-channel gradually increases along the direction towards the outlet fluid tank.
4. The micro-channel heat sink of claim 3, wherein the width of the micro-channel gradually increases along the direction towards the outlet fluid tank.
5. The micro-channel heat sink of claim 3, wherein the depth of the micro-channel gradually increases along the direction towards the outlet fluid tank.
6. The micro-channel heat sink of claim 1, further comprising a plurality of channel walls separating the plurality of micro-channels, wherein the cross sectional area of the channel wall gradually decreases along the direction towards the outlet fluid tank.
7. The micro-channel heat sink of claim 1, wherein the cooling layer comprises a silicon material.
8. The micro-channel heat sink of claim 1, wherein the plurality of micro-channels are arranged in parallel.
9. The micro-channel heat sink of claim 1, wherein the upper cover layer can be joined to an electrical component using a thermal adhesive.
10. The micro-channel heat sink of claim 1, wherein the micro-channel can prevent backflow of bubbles in the boiling working fluid and instability of a two-phase flow resulting from the backflow.
Type: Application
Filed: May 16, 2008
Publication Date: Dec 18, 2008
Applicant: NATIONAL TSING HUA UNIVERSITY (HSINCHU)
Inventors: CHIN PAN (HSINCHU CITY), PO CHANG LI (KAOHSIUNG CITY), CHUN TING LU (KAOHSIUNG CITY), KUN CHENG LIN (TAICHUNG COUNTY)
Application Number: 12/122,218
International Classification: F28D 15/00 (20060101);