SUBJECT: Ph.D. Dissertation Defense
BY: David Woodrum
TIME: Friday, December 6, 2019, 12:00 p.m.
PLACE: MARC Building, 201
TITLE: Mechanical Characterization of Brittle Interface for High-Pressure Two-Phase Microfluidic Cooler
COMMITTEE: Dr. Suresh K. Sitaraman, Chair (ME)
Dr. Muhannad S. Bakir (ECE)
Dr. Yogendra K. Joshi (ME)
Dr. Peter A Kottke (ME)
Dr. Shuman Xia (ME)
Dr. Ross K. Wilcoxon (UTC)


The overall goal of this work is to develop a reliable microfluidic architecture for high heat-flux microelectronic applications by experimentally characterizing glass-silicon interface. This is achieved through an innovative technique and by employing numerical simulations and analytical models to ensure that the interface will not crack or delaminate under given pressure and temperature conditions. This work also aims to examine microfluidic architectures of different generations and designs to achieve its goal. Thus, the first objective of this work is to perform a thermomechanical analysis of a high-pressure, two-phase microfluidic cooler and a low-pressure, high-performance on-chip cooler using numerical models. The next objective will be to develop a reliable microfluidic architecture with an appropriate pin-fin configuration. This requires characterizing and understanding the failure modes through analysis of various generations of prototype thermal test vehicles for high-pressure two-phase cooling. These models will underscore the significance of understanding, in particular, the failure mode of the silicon-glass interface and provide context for the third and fourth objectives. The third objective involves analyzing the mechanical behavior of the silicon-glass interface with various pin fin geometries through multiple finite-element models and using these models to design experimental pressure test devices. These models and resulting devices will work in tandem with the experimental methodology of Objective 4. The fourth and final objective is to develop an innovative experimental test technique for evaluating the mechanical performance of a silicon-glass interface. By using a pressurized cavity to apply load on the silicon-glass interface, this test will more accurately mimic the working conditions of a high-pressure microfluidic cooler than existing test techniques for evaluating brittle interfaces.