Intermetallic compounds (IMCs) formation is important for the reliability of microelectronic devices, especially for flip chip solder joint. It can be accelerated or decelerated by imposing a direct electric current normal to the interface. These effects are analyzed by including electromigartion-driven and back stress-dominated interchange of atomic species in a conventional analysis of reaction layer growth in a binary system controlled by interdiffusion.
This dissertation research consists of two parts that are related to the IMCs growth between the two different composites. The first part of the dissertation involves the development of a generalized phenomenological model for use in the interpretation of effects of electromigration on IMC growth by considering reaction and diffusion of two species. When both reaction and mass transfer are important, the model predicts cathode thickening and anode thinning if the electro-migration effect on the dominant diffusion species is more pronounced. Cathode thinning and anode thickening occur when the electro-migration effect on the minor diffusion species is more pronounced. Simultaneous cathode and anode thinning happens when there are two diffusion species and the diffusion and electro-migration fluxes are comparable. Simultaneous cathode and anode thickening occurs when mass transfer is the limiting step and diffusion flux is negligible compared to electromigration. This model was found to be consistent with experiment data on IMC growth in the literature given the limited amount of information on effective charge of various species
The second part of the dissertation research concerns the formation of unusual cruciform pattern at the interface between two different components. During the interaction of some solid-liquid and solid-solid system, the interaction layers have been observed to give rise to an unusual cruciform pattern. We propose that this morphology after reaction was directly dependent on the nature of the solid substrate during the growth. Depending on the diffusion process, two cases have to be considered. If the direction of metalloid diffusion is from the outside to the inside, the building of the layer occurs under the initial interface. And if the free volume of solid substrate is much smaller than the atomic volume of diffusing atom, stresses appear in the layers and result in rupture at the corners. A cruciform pattern will be observed. Contrarily, if the free volume of solid substrate is much larger than the atomic volume of diffusing atom, the edges should take a convex shape. This mechanism must be substantiated by more experimental studies

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