| Summary: | With the rapid advancement of technology, the form factor of integrated circuits decreases. This has resulted in the reduction in the available area of heat dissipation causing a high level of heat flux to develop which certain integrated circuits are unable to withstand. Therefore, in order to maintain the reliability and working performance of such integrated circuits, advanced thermal management technologies is required. Due to its exceptional heat dissipation capabilities in comparison with other cooling techniques such as liquid cooling, refrigeration cooling, and air-cooling, heat pipes such as the vapor chamber have been extensively studied.
In this project, a mathematical model has been developed to optimize the parameters of the biporous structures with micro channels among the pillars. By shortening the liquid prorogation length inside biporous media, the viscous force of the water flow can be reduced. An experimental rig has been built to test the performance of the designed samples at ambient conditions and compared with the derived mathematical model.
Photolithograph and deep reactive-ion etching (DRIE) are used to fabricate the samples’ pillar areas with varied parameters for further comparisons. A Platinum (Pt) micro-heater is used to simulate the heat concentration of the working device while the four resistances thermal detectors (RTDs) are used to measure its temperature in resistance value. These devices are fabricated using the process called electron beam deposition and lift – off process.
During the experiment, the water level remains constant in the reservoir throughout the experiment. As additional water is pumped into the reservoir, the water is drawn into the evaporator due to the capillary force of the wick structure. After testing a series of samples, the Resistances Thermal Detectors (RTDs), heat load and flow rate data were recorded.
After conducting several experiments, the conclusion in this Final Year Project is that a sample with a higher Island width, height and with a small pitch produces the best performance for the evaporator.
Therefore, it is important to understand the parameters of the evaporator for effective cooling. The mathematical model thus paves the way to designing silicon vapor chambers in the future.
Koh Han Pin
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