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This paper proposes a parametric simulation plan for UBM geometry with different UBM rim angles, diameters and thicknesses. The parameter plan for the solder bump with different heights and diameters, and different shapes is also investigated. The goal of this study is to understand the impact of the die shrinkage on solder joint reliability under electromigration failure, and to optimize the UBM...
This paper investigates the degradation behaviour of lead-free Sn96.5Ag3.0Cu0.5 solder. A series of isothermal mechanical cycling tests under different conditions has been conducted. The tests were monitored in-situ with a high magnification camera system. Optical observations are presented from selected tests, showing the surface morphology during testing. In addition to the optical investigation,...
The purpose of this research is to enhance the structure of the 204-pin small outline dual in-line memory module (SODIMM) against the drop impact. According to the JEDEC regulations, the enhancement of PCB clips should be attempted to increase the resistance against drop impact. From high speed camera observation, the SODIMM module is pushed away from the PCB clips during drop impact. Therefore, the...
We present a simplified model of mechanical behavior of large cantilever arrays with discoupled rows in the dynamic operating regime. Since the supporting bases are assumed to be elastic, cross-talk effect between cantilevers is taken into account. The mathematical derivation combines a thin plate asymptotic theory and the two-scale approximation theory, devoted to strongly heterogeneous periodic...
The paper reports the results of a systematic improvement project on the thermal cycle (TC) lifetime prediction of BGA memory modules with SnAg1.0Cu0.5 and SnAg1.0Cu0.5Ni0.05 solder alloys. The pre-existing lifetime modeling scheme allowed predictions with an inaccuracy factor of about 1.6plusmn1 on average while in TC experiments, the characteristic lifetime, N63, showed a standard deviation of about...
Actuation, sensoring and control in arrays of MEMS require spatially distributed periodic electronic circuits. For very large sized arrays, say 1000 times 1000 MEMS or cells, on the same chip, simulation requirements for electronics are far away from standard algorithm capabilities. One of the authors has shown in a theoretical paper, that a homogenization modeling method, previously developed for...
The effects of mechanical shocks on polysilicon MEMS accelerometers are here investigated within the frame of a multi-scale finite element approach. To accurately model MEMS dynamics and possible failure events, three length-scales are explored: macroscale, characterized by stress waves propagating inside the package and eventually impinging upon sensor anchors; mesoscale, characterized by forced...
In the present paper the automated optimization of the exposure dose for UV moving-mask lithography is presented. Moving-mask lithography is a promising new technique for micro patterning thick positive photo resists. The design task is to design the mask and the mask motion such that the requested micro pattern is achieved as good as possible. As an intermediate step towards a computational engineering...
Modelling of MEMS is one of the difficulties faced in advancing the design. The parameters fed to the simulator consist of the material properties and the geometry of the structure. Material wise, researchers are working on developing precise characterisation techniques to ameliorate the mechanical definition of structural material used. More work is now ongoing to ameliorate the fabrication process...
The dynamic response of electro-mechanically actuated micro structures is governed by nonlinear effects which directly influence their performance. To date, most work in the field of micro/nano systems is done experimentally and documented theoretical research consists of nonlinear lumped-mass models as well as continuum mechanics approaches. Existing and codified computational tools for micro-electromechanical...
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