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Electromigration of eutectic SnPb flip chip solder joints and their mean-time-to-failure (MTTF) have been studied in the temperature range of 100 to 140 °C with current densities of 1.9 to 2.75×10[sup 4] A/cm[sup 2]. In these joints, the under-bump-metallization (UBM) on the chip side is a multilayer thin film of Al/Ni(V)/Cu, and the metallic bond-pad on the substrate side is a very thick, electroless Ni layer covered with 30 nm of Au. When stressed at the higher current densities, the MTTF was found to decrease much faster than what is expected from the published Black’s equation. The failure occurred by interfacial void propagation at the cathode side, and it is due to current crowding near the contact interface between the solder bump and the thin-film UBM. The current crowding is confirmed by a simulation of current distribution in the solder joint. Besides the interfacial void formation, the intermetallic compounds formed on the UBM as well as the Ni(V) film in the UBM have been found to dissolve completely into the solder bump during electromigration. Therefore, the electromigation failure is a combination of the interfacial void formation and the loss of UBM. Similar findings in eutectic SnAgCu flip chip solder joints have also been obtained and compared. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Reports on the measurement of shear strengths of the solder joints for Sn-Ag eutectic alloy with the Au/electroless Ni(P)/Cu bond pad for three different electroless Ni(P) layers. Investigation of fracture surfaces by scanning electron microscopy equipped with energy dispersed x-ray; Increase in shear strength when the P-rich Ni layer disappears from a prolonged reaction.

Presents a study which investigated the morphology, cap diameter, and cross-sectional image of eutectic alloy of lead and tin (SnPb) solder caps as a function of varying surface films, reflow time, and reflow temperature. Experimental procedures used to conduct the study; How leadframe packaging for plastic encapsulated electronics products is associated to SnPb solder or similar solders; Results and discussion of the study.

Studies the failure behavior of Ni and Ni2Si contacts on both n+-Si and p+-Si upon current stressing. Use of a pair of cathode and anode contacts in testing; In situ resistance data; Silicide formation at the damaged contacts; Cross-bridge Kelvin structure used for the contact resistance measurement.

Studies the microstructural evolution of rodlike defects as well as their correlation with the formation of dislocation loops in heat treatment of amorphized silicon. Plan-view transmission electron microscopy; Distribution of rodlike defects; Cross-sectional transmission electron microscopy.

Studies the end-or-range dislocation loops in silicon-implanted silicon. Performance of two kinds of post-implantation anneals; Observation of the ripening of faulted Frank dislocation and perfect prismatic dislocation loops; Distribution profiles of the loops; Analysis of the ripening behavior of the two types of dislocation loops.

Elementary theory of mass-transfer in two-phase alloy under electromigration with account of two competing mechanisms of the fluxes equilibration is presented. These two competing mechanisms are Kirkendall effect and backstress. Various versions of Monte Carlo models for simultaneous simulation of structure evolution kinetics and of mass-transfer kinetics under high-density current are presented. Possibility of self-organization with minimization of Joule heating is demonstrated. [ABSTRACT FROM AUTHOR]

Presents a study which assessed the effect of supersaturation of copper on reaction and intermetallic compound formation between tin-copper solder and thin film metallization. Energy dispersive spectroscopy composition analysis of intermetallics in tin-copper solders; Factor which may control the reaction between molten SnPb solder and Al/Ni/Cu thin films; Functionality of the supersaturation of copper in the hypereutectic Sn-3Cu solder.

Examines the dynamic process of the particle-particles interaction in electrorheological fluids using time-regulated high-voltage power supply. Adjustments on the field strength; Measurements Application of the sensitive shear stress device; Stages of different effect; Measurement of aggregation of the microsphere; Interactions of particles.

In situ electromigration experiments were carried out to study electromigration-induced failure in the upper and lower layers in dual-damascene Cu test structures. The observations revealed electromigration-induced void movement along the Cu/dielectric cap interface. It supports the premise that Cu/Si3N4 interface acts as the dominant electromigration path. However, the observed void nucleation occurs in the Cu/Si3N4 interface at locations which are far from the cathode, and void movement along the Cu/Si3N4 interface in opposite direction of electron flow eventually causes void agglomeration at the via in the cathode end. The different electromigration behaviors of the upper and lower layer dual-damascene structures are discussed. [ABSTRACT FROM AUTHOR]

Room-temperature electromigration occurs in a thin stripe of eutectic SnPb solder stressed by a current density of 10[sup5] amp/cm[sup2]. Hillocks and voids grow at the anode and the cathode, respectively. While the dominant diffusion species in Sn in this two-phase alloy, the growth of the hillocks, surprisingly, originates from the Pb grains. [ABSTRACT FROM AUTHOR]

Examines the microstructural evolution of {113} rodlike defects and {111} dislocation loops in silicon-amorphized silicon. Use of cross-sectional transmission electron microscopy to evaluate microstructural evolution; Stages of change undergone by the rodlike defects during postimplantation anneals; Nucleation of the dislocation loops at the interface.

Examines the soldering reaction between eutectic SnPb and plated palladium/nickel thin films on copper leadframe. Absence of stable wetting angle; Comparison of spike formation between the thin and thick layers; Existence of a uniform Ni[sub 3]Sn[sub 4] compound layer at the interface; Assistance of solder spreading through compound formation.

Examines the asymmetric spalling of copper-tin compound spheroids in solder joints on silicon wafers. Assistance of spheroid formation by ripening reaction among the compound grains; Role of gravity for asymmetric spalling of compound spheroids; Use of sandwich structure to observe the asymmetric spalling phenomenon.

Examines the size distribution of end-of-range (EOR) dislocation loops in silicon-implanted silicon. Fabrication of an ultrashallow junction in complementary metal-oxide semiconductor; Dependence of EOR dislocation loops on the implantation; Use of slow furnace annealing and transmission electron microscopy specimens.

Examines the rate of consumption of copper in soldering reactions in electronic packaging technology. Observation of the dissolution kinetics of copper into a molten solder; Thickness of copper during soldering; Kinds of eutectic intermetallic compounds; Inability of intermetallic compounds to form layered structures.

Examines the wetting of eutectic tin-lead solder and palladium. Formation of intermettalic compound as lamellae into the molten solder; Role of palladium in enhancing the soldering process; Application of noble metals to electronic packaging technology.

Examines stress distribution and migration in interconnecting studs of a three-dimensional multilevel device structure. Correlation between calculated locations of stress and observed failure sites; Details on the failure mechanisms associated with different stress components; Effects of temperature on the calculated locations of stress concentration.

Examines the formation of stable shell of YBa[sub 2]Cu[sub 4]O[sub 8] upon oxygen outdiffusion. Investigation on the 124 phase formation; Explanation on the thermal stability of the 124 phase; Determination on the activation energy of oxygen diffusion.