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1	Interface Balance Laws, Growth Conditions and Explicit Interface Modeling Using Algebraic Level Sets for Multiphase Solids with Inhomogeneous Surface Stress Pavankumar Vaitheeswaran (9435722) 16 December 2020 (has links) Interface balance laws are derived to describe transport across a phase interface. This is used to derive generalized conditions for phase nucleation and growth, valid even for solids with inhomogeneous surface stress.<div><br></div><div>An explicit interface tracking approach called Enriched Isogeometric Analysis (EIGA) is used to simulate phase evolution. Algebraic level sets are used as a measure of distance and for point projection, both necessary operations in EIGA. Algebraic level sets are observed to often fail for surfaces. Rectification measures are developed to make algebraic level sets more robust and applicable for general surfaces. The proposed methods are demonstrated on electromigration problems. The simulations are validated by modeling electromigration experiments conducted on Cu-TiN line structures.</div><div><br></div><div>To model topological changes, common in phase evolution problems, Boolean operations are performed on the algebraic level sets using R-functions. This is demonstrated on electromigration simulations on solids with multiple voids, and on a bubble coalescence problem. </div> Mechanical Engineering Interface balance laws Inhomogeneous surface stress Phase nucleation condition Phase growth condition Electromigration Algebraic level sets Isogeometric Analysis Boolean compositions Algebraic point projection Dixon resultant
2	THERMODYNAMIC RESTRICTIONS ON SURFACE STRESS, AND ITS ESHELBIAN FORMS, FOR AN INTERFACE DRIVEN BY MECHANICAL, THERMAL AND CHEMICAL FORCES WITH APPLICATIONS TO SNBI SOLDER JOINTS Pei-En Chou (19691614) 19 September 2024 (has links) <p dir="ltr">This thesis explores the thermodynamics and mechanics of reaction-diffusion interfaces in solid materials, focusing on configurational forces for bulks and surfaces, which are essential in understanding phenomena like electromigration, phase separation, and void evolution. The work is divided into four themes: bulk and surface configurational mechanics, electromigration in solder joints, and solid mixture theory. The thesis develops theories based on continuum mechanics and configurational forces, deriving Eshelby stress tensors and balance laws for interfaces. Experimental work on electromigration in SnBi solder joints is used to validate the theory. The research contributes to advancing the understanding of solid-state diffusion and phase evolution in engineering materials.</p> Microelectronics Solid mechanics interconnect deformation interconnect test structures Solid mechanics Configurational Force Moving interfaces Eshelby Second Law of Thermodynamics fracture mechanics theory Continuum mechanics. surface stress f Interface balance laws current crowding EDX characterization sem characterizations X-ray tomographic microscopy FIB methods Reaction Diffusion Theory Solid state diffusion electromigration device cleanroom fabrication

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Interface Balance Laws, Growth Conditions and Explicit Interface Modeling Using Algebraic Level Sets for Multiphase Solids with Inhomogeneous Surface Stress

THERMODYNAMIC RESTRICTIONS ON SURFACE STRESS, AND ITS ESHELBIAN FORMS, FOR AN INTERFACE DRIVEN BY MECHANICAL, THERMAL AND CHEMICAL FORCES WITH APPLICATIONS TO SNBI SOLDER JOINTS