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In this study, lead free (Sn-4Ag-0.5Cu (SAC)) and lead (62Sn-36Pb-2Ag (SP)) solder joint on various surface finished of ball grid array (BGA) pad, such as Immersion Tin (ImSn), Organic solderability preservatives (OSPs), Ni-P/Pd/Au (ENEPIG), and Ni-P/Au (ENIG) was investigated by its interface morphology and its physical properties. To evaluate the mechanical and physical properties of BGA pad with...
We demonstrate a novel biosensor for in vitro observation of cell membrane behaviors associated with proteins, adapting a supported lipid bilayer (SLB) that mimics the cellular membrane and using label-free surface plasmon resonance spectroscopy (SPRS). In this study, we focus on the detection of membrane behaviors by the specific types of Cu/Zn-superoxide dismutase (SOD1) species, which have been...
We study the impact of microstructure on nucleation and evolution of electromigration induced voids. The grain boundaries are described with a comprehensive model which includes the dynamics of mobile and immobile vacancies in dependence of mechanical stress. The surface of an evolving void is modeled by a three-dimensional level-set algorithm. Simulations have shown that the constellation of grain...
To improve the bondability of copper chip interconnect, a Si/Ti-Cu-Ag structure was designed and fabricated using evaporation method. Some analytical methods such as SEM, AFM, XRD and XPS were used to characterize the Ag nanofilm metallization and its bondability. It was found that the evaporated Ag metallization has good surface state and samll particle size, which could diffuses readily in the wire...
Sn whisker growth is considered as a crucial reliability issue in the electronic packaging industry, especially with the massive application of Pb-free solder alloys. In this paper, we report our fundamental studies on Sn whisker growth through accelerated tests. Excessive rare earth element addition is one way we employed to investigate the kinetics of whisker growth. Several aspects of the morphological...
The present paper addresses the formation and evolution of microstructure and crystal structure of electroplated copper columns. Copper columns of different size have been plated on Au seed layer for a series of periods of time from half an hour to three hours and characterized by Focused Ion Beam (FIB) and XRD. It was found that not only the growth process during plating but also accompanying recrystallization...
Finding new under bump materials (UBM) is of significant importance with the shrinkage of pitch size in advanced high density packaging. FeNi alloy has been found to be a good UBM candidate for its slower interfacial reaction during reflow and aging. However, solderability of FeNi has to be improved. 58Fe42Ni and 92Fe8Ni alloy platings with electrodeposited tin finish were investigated by wetting...
It is found that the morphologies and orientations of Cu6Sn5 can be well controlled through designing orientations of Cu single crystal substrates. On (001) and (111) Cu single crystals, Cu6Sn5 grains display regular prism-type morphology and align either along two perpendicular directions or along three directions having an angle of 60deg between each other. By electron backscatter diffraction (EBSD)...
Nano-coned array of Cu were prepared by electroless plating with special crystallization conditioning agent. The morphologies of nano-coned array were observed by FE-SEM. The influences of active time in PdCl2, concentration of NiSO4middot6H2O, crystallization conditioning agent, pH and temperature of plating solution were discussed. Then, the possible reasons of the influence on the growth of nano-coned...
The absorption behavior of Ag3Sn particles on the surface of intermetallic compounds (IMCs) formed at Sn-3.5Ag-xCu/Cu (x=0, 0.7, 1.5 wt. %) interfaces was studied. The Sn-3.5Ag-xCu/Cu solder joints were prepared by reflow soldering at 260degC for different time. The X-ray diffraction results showed that the dominant IMCs formed at Sn-3.5Ag-xCu/Cu interfaces were Cu6Sn5. For Sn-3.5Ag/Cu and Sn-3.5Ag-0...
Adhesion has been identified as one of the key elements in solving failure problems in electronic packaging. Understanding and improving the adhesion between epoxy molding compound (EMC) and leadframes is thought to be a key step towards improving package performance. The objective of this work was to study the effect on adhesion behavior and delamination of plastic packages using various metal coated...
Structural and morphological transformations of an atomically clean Si(111) surface at initial stages of copper deposition were studied by in situ ultrahighvacuum reflection electron microscopy. The monatomic steps motion in the step-down direction and the change of the electron microscopy contrast along atomic steps were observed during the submonolayer copper deposition onto the substrate at 850degC...
Cu2ZnSnS4 (CZTS) thin films were grown by ionic liquid electrodeposition technique. Sulfurization of the stacked layers was achieved in elemental sulfur vapor at 450degC for 2 hours. Detailed structural and optical characterizations of the films were performed.
We present the application of a state of the art electromigration model on a dual damascene interconnect with typical copper microstructure. The influence of the microstructure on the formation and development of an electromigration induced void is studied by simulation and the results are compared with experiments. A close investigation has shown that the network of grain boundaries has a decisive...
CuInAl precursor films with varying Al/(Al+In) ratios were co-sputtered onto Mo coated soda-lime glass substrates. Samples were then selenized under high vacuum using thermally evaporated elemental selenium. Single-step and two-step selenization heating profiles were investigated. Single-step samples resulted in better Mo-CuInAlSe2 adhesion than those selenized using the two-step approach. Precursor...
Solar cells based on polycrystalline Cu(In,Ga)Se2 (CIGS) absorber layers have shown high potential for low cost photovoltaic energy conversion. Our group has achieved 18.1% efficient cells on glass substrates and 14.1% on flexible polyimide foils without antireflection (AR) coating. These results were achieved by applying a three-stage evaporation process with common growth rates of about 35 nm/min...
Electro-conductive textiles are increasingly demanded in our today's technology-driven world as they combine functionalities with high wearing comfort. Thus, they are, for instance, very suitable for being applied as electrodes integrated in clothing to measure biomedical parameters of a person. For this purpose they need to be modified to provide reliable electro-conductive properties. This can be...
Summary form only given: Plasma immersion ion implantation (PIII) is an effective method to modify the mechanical properties and chemical properties of materials, especially metals. In comparison with conventional ion implantation, PIII can treat samples with complicated shape due to its non-line-of-sight characteristics. The improved mechanical properties can usually be attributed to radiation-enhanced...
A non-vacuum technique was demonstrated for the growth of Cu(InGa)Se2 (CIGS) thin films. The technique used is an ink formulation containing sub micron size particles of Cu/In/Ga. A thin metallic precursor layer was first formed by coating this ink onto the Glass/Mo substrate by doctor blade technique. The precursor film was dried followed by reduction reaction in hydrogen atmosphere. The precursor...
This paper discusses the use of a hydrophobic thiol based compound as adhesion promoter for copper (Cu)-epoxy interface. The motivation of this study is the long term reliability of the interface. In order to solve the moisture related reliability problem at the interface, thiol based molecules having hydrophobic characteristic (SAM N) is introduced at the interface. The rationale is to reduce the...
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