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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Transient Analysis on Structural Responses of Solder Joints under High-Speed Impact

Wang, Chang-chin 19 July 2007 (has links)
The purpose of thesis is to study the transient analysis of structural responses of solder joints under high-Speed impact. By using the experimental and simulation analysis. The experimental work can be divided into six parts, such as different impact speeds, different solder¡¦s components, different pad finishing, different UBM and Runner, and different thickness of PBO. From experiments, the variations of solder joint strength and mechanical properties were received and discussed and the failure mode. The empirical results show that maximum impact force on solder joints decreases as the impact speed increasing. The solder joint strength becomes stronger with the solder adopting elements of Ni and Co. The strength of solder ball was reduced significantly after a reflow. The intermetallic compound strength reduces with solder ball adopting high content of Ag. In impact test, the resistance of UBM of TiAl is better than that of TiAlTi. The runner adopted with the element Pd can improve the IMC reliablility to reduce Mode I failure. However, the PBO thickness has little influence on IMC strength. From the numerical results, in the consideration of strain rate on solder joint the mechanical properties of solder joint could be effectively investigated. According to the different IMC strength there will produce three failure modes of solder ball and the impact force becomes higher as the IMC strength setting higher. If the lower yield stress is considered in lower IMC strength, the impact force is not the highest of all, but the time duration is the highest of all.
2

Modelling the SAC microstructure evolution under thermal, thermo-mechanical and electronical constraints / Modélisation de l’évolution de la microstructure d’alliage SAC sous contraintes thermiques, thermomécaniques et électriques

Meinshausen, Lutz 25 March 2014 (has links)
L'assemblage tridimensionnel des circuits microélectroniques et leur utilisation dansdes conditions environnementales extrêmement sévères nécessitent ledéveloppement d’alternatives plus robustes pour les contacts électriques. Unetechnique prometteuse est la transformation des contacts de brasure conventionnelleen composés intermétalliques (IMC). Ce processus est appelé « Transient LiquidPhase Soldering » (TLPS).Dans ce contexte, des tests accélérés permettant la formation d’IMC parélectromigration et thermomigration ont été effectués sur des structures « Packageon Package ». L'objectif principal est le développement d'un modèle généralpermettant de décrire la formation des IMC dans les joints de brasure. Combiné avecune analyse par éléments finis ce modèle pourra être utilisé pour prédire la formationdes IMC dans les joints de brasure pour des structures et des profils de missiondifférents. Le modèle de formation des IMC pourra être utilisé pour optimiser unprocessus TLPS. / A further miniaturization of microelectronic components by three dimensionalpackaging, as well as the use of microelectronic devices under harsh environmentconditions, requires the development of more robust alternatives to the existing Snbased solder joints. One promising technique is the diffusion and migration driventransformation of conventional solder bumps into intermetallic compound (IMC)connections. The related process is called transient liquid phase soldering (TLPS).Against this background an investigation of the IMC formation under consideration ofelectromigration and thermomigration was performed. For the stress tests Packageon Package structures are used. The final result is a general model for the IMCformation in solder joints. Combined with a Finite Element Analysis (FEA) this modelis used to predict the IMC formation in solder joints for a broad range of boundaryconditions. In future the model of the IMC formation can be used to optimize a TLPSprocess.

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