Thermo-mechanical design and reliability of high-performance ultra-thin vapor chambers
Abstract/Contents
- Abstract
- Silicon-based vapor chambers are an appealing choice for electronics cooling application due to their low thermal resistance and ease of system-level integration. However, challenges in high heat flux applications necessitates development of high-performance evaporator wicks for these two-phase cooling solutions. Here, we design, fabricate, and characterize a novel hybrid microporous evaporator wick capable of removing > 150 W from 5×5 mm2 hotspot (> 600 Wcm-2 heat flux with thermal resistance of 0.02 oCcm2W-1). We use copper wire meshes (CWMs) to provide liquid feeding and copper inverse opal (CIOs) for boiling. Surface oxidation of the copper is a critical degradation mechanism that must be addressed to preserve the integrity and hydrophilicity of the wick. We systematically investigate the contact angle change of micro porous copper. To avoid hydrophobicity, we propose to pre-oxidize the copper evaporator wick to form a hydrophilic cupric oxide CuO. Furthermore, we develop a recipe for creation of a reliable superhydrophilic layer for micro porous wick application. We investigate effect of various maintenance protocols to ensure superhydrophilicity of the wick for long term functionality. Thermo-fluidic performance of ultra-thin vapor chambers has been studied extensively in the past two decades, however; the thermo-mechanical design and reliability of these devices has not received much attention. The mechanical design and reliability of the vapor chamber is crucial for avoiding the device breakdown or leakage due to the high internal pressure. We develop a parametric model for thermo-mechanical design and structural analysis of an ultra-thin (1 mm thickness) miniature (15×15 mm2 area) silicon vapor chamber. We study the effects of various design parameters such as cavity area, cavity thickness, and fillet radius. We introduce the circular cavity design for the vapor chamber application. To increase the mechanical reliability, we propose the implementation and study the design parameters of various mechanical support structures such as ribs, crossbars, and micro-post arrays. The critical point of the mechanical design is the evaporator-condenser bonding area. Gold-tin and gold-silicon eutectic bonding are proposed as the bonding materials and methods. The samples and the tensile test setup are designed, fabricated, and tested specifically for the vapor chamber application. Findings of this study are largely beneficial in development of silicon-based heat spreaders, high-performance thermal rectifiers, next-generation heat routing technologies and heterogeneous two-phase cooling devices.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2022; ©2022 |
| Publication date | 2022; 2022 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Soroush, Farid |
|---|---|
| Degree supervisor | Goodson, Kenneth E, 1967- |
| Thesis advisor | Goodson, Kenneth E, 1967- |
| Thesis advisor | Howe, Roger Thomas |
| Thesis advisor | Kenny, Thomas William |
| Degree committee member | Howe, Roger Thomas |
| Degree committee member | Kenny, Thomas William |
| Associated with | Stanford University, Department of Mechanical Engineering |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Farid Soroush. |
|---|---|
| Note | Submitted to the Department of Mechanical Engineering. |
| Thesis | Thesis Ph.D. Stanford University 2022. |
| Location | https://purl.stanford.edu/nw909qz5894 |
Access conditions
- Copyright
- © 2022 by Farid Soroush
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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