The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Due to a weak adhesion, the delamination occurred frequently in the interface between the epoxy compounds and lead that results in a performance failure normally. Several treatments, such as plasma and chemical modifications, have been developed and applied to enhance the bonding force in the interface of both materials. In this study, an anchor shape of the lead, as a mechanical locking microstructure,...
This paper presents the relations between processing, microstructure and mechanical reliability of copper pillar bumps (CuPi). Two sets of samples were manufactured: Cu/SnAg and Cu/Ni/SnAg with diameters between 15 and 20 µm. From the microstructure point of view: at these dimensions and for simulated reflows, up to 5, intermetallic compounds (IMC) follow a classical power law with a time exponent...
In this study, the electrical behavior of CCTO/SiO2 composites have been analyzed. The ceramic composite was made of CaCu3Ti4O12 coated with SiO2 by sol-gel method. The composites were made of SiO2 concentration and sintered in different temperature. The effect of SiO2 concentration and sintering temperature on the microstructure and non-ohmic behavior of composites were investigated. The breakdown...
Wide band gap semiconductors have becomevery attractive for power electronics because of their excellentproperties at high power and high junction temperaturesabove 300°C. However, the maximum operation temperaturesof conventional packaging materials, like tin-based solders oreven tin-lead solders, are limited to around 220°C. Thus, a newpackaging material with a higher melting temperature must bedeveloped...
High thermo-mechanical stresses are usually induced in through silicon via (TSV) structures due to the mismatch of coefficients of thermal expansion (CTE) between copper and silicon in Cu filled TSVs, which has brought an increasing concern for the reliability problems during fabrication process and operation of electronic devices. The size, shape and orientation of Cu grains in TSVs and their effects...
The high temperature storage test (HTST) was conducted on the SnAgCu/Ni-W-P and Ni-Fe solder joints. While the conventional Ni-P solder joints were used as comparison to study the diffusion barrier effect of Ni-W-P and Ni-Fe under bump metallization (UBM). Both cross section and top view for the microstructural evolution of solder joints during 150°C aging were observed by the scanning electron microscope...
The reliability of copper through-silicon vias (TSVs) has been shown to be largely determined by the microstructure and extrusion statistics, and the mechanism for this requires further investigation. Synchrotron x-ray microdiffraction is an advantageous technique for TSV measurements due to its high beam intensity, which allows for full stress derivation with submicron resolution, and its nondestructive...
Corrosion reliability of five Sn-Ag-Cu (SAC) based lead-free solder alloys under humid and corrosive conditions has been investigated to understand the microstructure effects on corrosion performance. Electrochemical experiments such as potentiodynamic and potentiostatic tests were conducted in 3.5 wt% sodium chloride electrolyte at room temperature. Microstructure of the solder alloys and corrosion...
Predominant high melting point solders for high temperature electronics contain lead (Pb), which will soon be banned by environmental regulations as in most of consumer electronics. In an effort to replace the Pb-based solders with a new high-temperature capable material, we developed a transient liquid phase (TLP) bonding of bismuth (Bi) and nickel (Ni). A molten Bi (m.p. of 271°C) strongly reacts...
Influence of Bi(Mg0.5Ti0.5)O3 (BMT) and KCl additives on phase formation, crystal structure, microstructure, dielectric and ferroelectric properties of ceramics with compositions close to the Morphotropic Phase Boundary in the (Na0.5Bi0.5)TiO3 - BaTiO3 (NBT-BT) system has been studied. The results obtained proved that modification of NBT-BT compositions by BMT and KCl additives promoted to improvement...
In this paper, a novel method of fabricating 3D microstructures of polymer film is proposed based on ionic wind. For the first time, it is observed experimentally that liquid polymer on conductive substrates with non-conductive patterns spontaneously converges from non-conductive areas to conductive areas under the action of ion wind. Taking advantage of such a flow phenomenon, polymer 3D micropatterns...
Nowadays, micro joint has been a widely used technology for the vertical integration of 3D IC. Even so, however, a common phenomenon after high temperature storage test or reflowing is that considerable voids are left in micro joints. Considering the strong relationship between reliability and the microstructures of micro joints, it is of necessity and interest to verify the factors which affect morphologies...
In this investigation, Scanning Electron Microscopy (SEM) and Scanning Probe Microscopy (SPM) have been utilized to examine aging induced microstructural changes occurring within lead free solders. Unlike many prior studies, fixed regions in the solder joint cross-sections were monitored throughout the aging process, rather than examining different samples and/or different regions after the various...
Microstructure variation with post-patterning dielectric aspect ratio (AR) and post-plating annealing temperature has been investigated in Cu narrow wires. As compared to the conventional annealing at 100 ◦C for a feature AR of 2.6, both elevated temperature anneals and reduced AR structures modulated Cu microstructure, which then resulted in a reduced rate of electrical resistivity increase with...
In recent years, Sn-Bi solders get much attention because low temperature bonding technique is possible to reduce warpage of package and stress at solder joining. However, few studies attempted to their reliability and knowledge of microstructure of the solder bump. In this study, we investigated the difference of inter-metallic compounds (IMCs) formation between Sn57wt%Bi solder (Sn-Bi eutectic solder)...
Due to growing environmental concerns, lead-free solder materials are being widely used in electronic assemblies. The Anand viscoplastic constitutive model is frequently used to represent mechanical behavior of lead-free solder materials in finite element simulations. However, prior experimental results have demonstrated that properties of lead-free solder materials degrade over time when exposed...
Helical structure assembled by hydrogel microfibers is significant for culture of smooth muscle cells. However, the helical structure is only fabricated at the macroscale, while the fabrication of helical microstructure is still a challenge due to the lack of assembly method. In this paper, we propose a robotics-based assembly method to handle such challenge. An electromagnetic needle (EMN) is employed...
Induction hardening is one kind of surface hardening process and can improve the wear resistance of components for the combination of high surface hardness and high toughness core. However, it may contain noticeable amount of retained austenite in the matrix of martensite, affecting the structural and dimensional stability of rails. The research focuses on the analyses of the amount of the retained...
When exposed to a temperature changing environment, solder joints in electronic assemblies are subjected to cyclic mechanical loading due to the mismatches in coefficients of thermal expansion (CTE) of different assembly materials. Eventually, the cyclic loading results in fatigue failure of solder joints, which is one of the common failure modes in electronic packaging. Aging leads to solder microstructure...
Experimental decomposition of contributions of electron scattering events in deeply scaled interconnects has been complicated by the fact that grain size and line dimensions are generally not varied independently. In this paper, we describe a combination of experiments to examine scattering mechanism independently. The cross section of was changed by recessing individual copper interconnects from...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.