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The formation and propagation of void in flip-chip solder joints would reduce the reliability of solder interconnects obviously. Notably, continuously scaling down of the feature size of solder joints may greatly promote the formation and propagation of void in solder joints under electric current stressing. In addition, the elastic stress field induced by the externally applied stress has a big influence...
The effects of zinc-oxide/salt with different contents in the aluminum soldering flux on the interfacial microstructure of Sn-0.7Cu/6061Al and mechanical property of 6061Al/Sn-0.7Cu/6061Al joints were investigated. Results show that the flux containing zinc-oxide and zinc-salt can effectively remove the oxide film on surface of 6061Al and result in formation of corrosion pits at the interface of the...
Creep of solder joints usually takes place in serving electronics due to the high homologous temperature of lead-free solders. With scaling down the dimension of electronics, the size of solder joints shrinks sharply, which may influence significantly the mechanical performance of solder joints, including creep behavior. In this study, the creep behavior of micro-scale Cu/Sn-3.0Ag-0.5Cu/Cu joints...
The effect of electric current density on the creep deformation and fracture behavior of micro-scale Cu/Sn-3.0Ag-0.5Cu/Cu joints under electro-thermo-mechanical coupled loads was investigated in this study. Results show that all solder joints exhibit similar creep curves displaying typical three-stage creep characteristics regardless of the current density, which suggests that mechanical stress is...
With the advantages of non-contact, flexible, high energy density and local heating, the laser jet solder ball bonding (SBB) technique is widely used in electronic packaging. The reliability of laser jet SBB solder joints has long been concerned. As is well known, the wettability (i.e., the spreading ability) of the molten solder on the boding pad is a key factor influencing the formation and performance...
Low-temperature soldering of 6061Al by an aluminum solder paste consisting of a purpose-designed flux and Sn-0.3Ag-0.7Cu (SAC0307) solder alloy powder with different reflow process parameters (such as the heating rate, peak soldering temperature and joint thickness) and the reliability of the soldered joints were investigated in this study. With increasing the heating rate, the spreading performance...
The effect of the activators and surfactants in halogen-free fluxes on the wettability of Sn-0.7Cu-0.05Ni solder on Cu substrate (or under bump metallization, UBM) was investigated in this study. The spreading area of Sn-0.7Cu-0.05Ni solder on Cu substrate was used to estimate the wetting performance of the solder influenced by the activators with different amounts added in halogen-free fluxes. The...
The miniaturization of solder interconnects may lead to the excessive growth of brittle intermetallic compounds (IMCs) at the interface of solder joints, and this has brought serious reliability concern to flip chip (FC) and ball grid array (BGA) packages, in particular for the drop impact reliability of the solder joints in portable electronic products. In this study, the lap-shear behavior and critical...
The morphological evolution of Cu6Sn5 grains formed at the interfaces of “Sn-3.0Ag-0.5Cu/Poly-crystal Cu (PC-Cu)” and “Sn-3.0Ag-0.5Cu/Single crystal Cu (SC-Cu)” under different reflow conditions was investigated. Reflow experiments were performed at different peak temperatures of 230, 260 and 290°C corresponding to the dwelling time of 20s, 60s and 600s, respectively. The results show that Cu6Sn5...
Tacit knowledge forms foundation and source of core-competitiveness and can play more significant role on technology innovation of firms. Firms need to develop tacit knowledge to gain competitive advantage. However, merely possession of knowledge does not guarantee an edge in competition. Quantity of tacit knowledge holders is smaller in intra-organization. To increase the quantity of tacit knowledge...
To study the effect of lead ion on the activity of roots of mung bean seedlings, the experiment adopts five kinds of different concentration lead ion to treat with the mung bean seedling, The results show that the higher concentration lead ion treatment resulted in lower activity of mung bean seedlings roots, and lessen protoplasmic surface charge of roots and the rate of electrophoresis migration...
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