SUBJECT: Ph.D. Dissertation Defense
BY: Yuanchen Hu
TIME: Monday, June 4, 2018, 10:00 a.m.
PLACE: Love Building, 210
TITLE: Microfluidic Thermal Management of 2.5D and 3D Microsystems
COMMITTEE: Dr. Yogendra Joshi, Chair (ME)
Dr. Zhuomin Zhang (ME)
Dr. Satish Kumar (ME)
Dr. Muhannad Bakir (ECE)
Dr. Xiaojin Wei (IBM)


Both 2.5 dimensional (2.5D) and 3 dimensional (3D) stacked integrated chip (SIC) heterogeneous architectures are promising to go beyond Moore's law for compact, high-performance, energy-efficient microsystems. These systems face significant thermal management challenges due to the increased volumetric heat generation and reduced surface area. In addition, highly spatially and temporally non-uniform heat generation occurs due to different functionalities of various chips. This dissertation focuses on addressing thermal management challenges for both 2.5D and 3D-SICs, by utilizing micro-gap liquid cooling with enhanced pin-fin structures. Single phase convection thermal performance of heterogeneous pin-fin enhanced micro-gap liquid cooling under non-uniform power map has been evaluated under steady state conditions. Thermal and hydraulic performance of a novel micro-channel dielectric coolant manifold have been parametrically studied by full-scale computational fluid mechanics/heat transfer simulations for multi-chip test structures of 2.5D-SICs. Non-uniform heterogeneous pin-fin structures in cold plates of 2.5D-SICs have been numerically optimized by using design of experiment method and full-scale computational fluid mechanics/heat transfer simulations. A compact thermal model accounts for both spatially and temporally varying heat-flux distributions for inter-layer liquid cooling of 3D-SICs with leakage simulation feature has also been developed as an thermal/electrical co-design tool. In addition to the active micro-gap liquid cooling thermal managements, this dissertation also investigates the passive micro-gap liquid cooling method, thermosyphon, for future 3D-SICs. Experimental characterization including heat transfer measurements, and bubble flow visualizations are performed under two phase conditions.