Graduation Semester and Year

2015

Language

English

Document Type

Thesis

Degree Name

Master of Science in Aerospace Engineering

Department

Mechanical and Aerospace Engineering

First Advisor

Ankur Jain

Abstract

Effective dissipation of heat generated in microelectronic devices during operation is critical for reliability and performance, particularly for advanced architectures such as microserver chips. Vapor chambers are a class of heat spreaders that have received much recent attention due to their passive nature and superior heat spreading capability. Several studies have investigated thermal performance of vapor chambers as heat spreading devices. However, developing a simple and accurate model which could be easily used in industry is still a big challenge. Moreover, more work needs to be done to optimize the performance of vapor chambers. For instance, developing a vapor chamber model for the increasingly common scenario of multiple chips and investigating the effects of heat density and chip orientation on the vapor chamber performance may provide designers with an opportunity to optimize the performance of these heat spreading devices. In this thesis, first, a simplified pure conduction model is developed to investigate thermal performance of a vapor chamber integrated with a single high power chip. Vapor chamber components are modeled as solid layers with effective thermal conductivities. Then, the single high power chip is replaced with a system of multiple lower power chips. The performance of the vapor chamber integrated with multiple lower power chips is compared with the single chip scenario. Results imply that due to a considerable reduction in junction temperature in multiple chips scenario, reducing the vapor space or copper wall thickness may result in a cost saving design opportunity of a vapor chamber with same functionality as the single chip scenario.Next, a multi-physics steady state and transient numerical simulation of a vapor chamber is carried out for both single and multiple chips scenarios. The model is capable of accounting for fluid motion in the wick structure. The performance of this model is compared with the simplified pure conduction model from the previous section. By inclusion of the fluid flow phenomena, the model is expected to predict the vapor chamber performance more realistically. Also, a study is conducted to investigate the effects of heat density and chip orientation on the performance of the vapor chamber. This work is expected to facilitate the quantification of thermal performance of vapor chambers and feasibility evaluation for future semiconductor thermal management needs. The model presented here captures salient physics, yet is simple enough to be used for thermal management design for semiconductor devices. The sensitivity study conducted in this work provides important information about the effect of different design parameters variables on vapor chamber performance. These contributions are expected to facilitate the adoption of vapor chamber technology in thermal management of semiconductor device.

Disciplines

Aerospace Engineering | Engineering | Mechanical Engineering

Comments

Degree granted by The University of Texas at Arlington

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