Graduation Semester and Year

2018

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Mechanical Engineering

Department

Mechanical and Aerospace Engineering

First Advisor

Dereje Agonafer

Abstract

Thermo-mechanical reliability estimation of electronic packages and modules provides an opportunity to predict the function life of semiconductor devices. The problem complexity lies in the fact that there are variety of electronic packages with different form factors, materials and manufacturing technology for various applications. The custom PCB ranges from very thin for portable application to very thick for power application. Despite conventional understanding and prior studies, some of the failures were not explained. This study reviews three failure problems for QFN, WCSP and BGA packages by characterizing the properties of custom PCB materials by layer removal process. Due to layup of the prepreg and copper material in the PCB, the bulk mechanical properties changes and impacts the reliability of the various packages and modules. The material properties of the PCB were determined using Instron Micro tester, Digital Image Correlation technique (DIC) and Thermal Mechanical Analyzer (TMA). The experimental data is then correlated with a FEM model to understand the mechanism. Next, several material/dimensional parameters affecting reliability of three problems were studied and chosen for optimization. The study proposes a methodology to optimize the overall system to mitigate the failure and prolong the usable life of packages.

Keywords

Board level reliability, PCB, Packages, QFN

Disciplines

Aerospace Engineering | Engineering | Mechanical Engineering

Comments

Degree granted by The University of Texas at Arlington

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