Date of Graduation

5-2022

Document Type

Thesis

Degree Name

Master of Science in Mechanical Engineering (MSME)

Degree Level

Graduate

Department

Mechanical Engineering

Advisor/Mentor

David Huitink

Committee Member

Paul Millett

Second Committee Member

Yarui Peng

Keywords

Energy consumption, Power electronics

Abstract

Power electronic advancement trends indicate that device power density will continue to increase as a result of increased power requirements and desired device form factor reduction in order to reduce weight and material costs and increase ease of integration into next-generation power systems. With these advancements come concerns regarding device reliability. The compounded effects of increased power density and form factor reduction in electrical conductors will yield amplified joule heating effects in addition to the already increasing device temperature profiles resulting from the incorporation of wide bandgap technology into power systems. Joule heating effects can lead to a variety of reliability problems, but there are two failure modes which pose serious potential threats for devices in the future. In electrical conductors, one phenomenon associated with elevated temperatures and power densities is electromigration. Electromigration refers to the migration of conductor material away from its initial position and is typically associated with electrical resistance increases and shorting. The second potential failure mode is related to thermomechanical stresses resulting from differing coefficients of thermal expansion at localized hot spots in a device. One of the most common ways to make connections inside of power electronic devices is by wire bonding. Small current carrying components, such as wire bonds, in power electronic devices may be subjected to a combination of electromigratory and thermomechanical related stresses during operation. Thus, it is advantageous for studies to be conducted to understand the impact that the combined effects of electromigration and mechanical stress have on wire bond reliability. This work introduces a novel accelerated test methodology for divulging the impacts of these combined effects on wire bonded interconnects and introduces a framework for reliability analysis based on accelerated testing methodologies.

Available for download on Sunday, June 30, 2024

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