Effect of Bump Shape on Current Density and Temperature Distributions in Solder Bump Joints under Electromigration

2012 ◽  
Vol 569 ◽  
pp. 82-87
Author(s):  
Yi Li ◽  
Xiu Chen Zhao ◽  
Ying Liu ◽  
Hong Li
Keyword(s):  
Current Density ◽  
Solder Bump ◽  
Three Dimensional ◽  
Maximum Temperature ◽  
Time To Failure ◽  
Element Analysis ◽  
Temperature Distributions ◽  
Maximum Current ◽  
Mean Time ◽  
Waist Radius

Three dimensional thermo-electrical finite element analysis was employed to simulate the current density and temperature distributions for solder bump joints with different bump shapes. Mean-time-to-failure (MTTF) of electromigration was discussed. It was found that as the bump volume increased from hourglass bump to barrel bump, the maximum current density increased but the maximum temperature decreased. Hourglass bump with waist radius of 240 μm has the longest MTTF.

Lead-Free and PbSn Bump Electromigration Testing

2005 ◽  
Author(s):  
Stephen Gee ◽  
Nikhil Kelkar ◽  
Joanne Huang ◽  
King-Ning Tu
Keyword(s):  
Cross Sections ◽  
Current Density ◽  
Critical Issue ◽  
Electronics Industry ◽  
Limiting Factor ◽  
Time To Failure ◽  
Solder Bumps ◽  
Free Solder ◽  
Mean Time ◽  
Eutectic Snpb

As the electronics industry continues to push for miniaturization, several reliability factors become vital issues. The demand for a high population of smaller and smaller solder bumps, while also increasing the current, have resulted in a significant increase in the current density. As outlined in the International Technology of Roadmap for Semiconductors (ITRS), this trend makes electromigration the limiting factor in high density packages. The heightened current density and correspondingly elevated operating temperatures are a critical issue in reliability since these factors facilitate the effects of electromigration. Therefore, as bump sizes continue to decrease, the study of electromigration reliability becomes crucial in order to understand and possibly prevent the causes of failure. A systematic study of electromigration in eutectic SnPb and Pb-free solder bumps was conducted in order to characterize the reliability of the Micro SMD package family. The testing includes both eutectic 63Sn-37Pb and 95.5Sn4.0Ag-0.5Cu solder bumps on an Al/Ni(V)/Cu under-bump-metallization. Mean-time-to-failure results are compared to Black’s Equation and cross-sections of the solder bumps are shown to analyze the mechanisms that led to failure.

scholarly journals Computer-based Finite Element Modeling of Insulated Tuohy Needles Used in Regional Anesthesia

2009 ◽  
Vol 110 (6) ◽  
pp. 1229-1234 ◽  
Author(s):  
Meredith B. Cantrell ◽  
Warren M. Grill ◽  
Stephen M. Klein
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Nerve Fiber ◽  
Current Density ◽  
Three Dimensional ◽  
Element Modeling ◽  
Maximum Current Density ◽  
Maximum Current ◽  
Distal Edge ◽  
Computer Based

Background Differences in needle design may impact nerve localization. This study evaluates the electrical properties of two insulated Tuohy needles using computational finite element modeling. Methods Three-dimensional geometric computer-based models were created representing two 18-gauge, insulated Tuohy needles: (1) with an exposed metal tip and (2) with an insulated tip. The models were projected in simulated human tissue. Using finite element methodology, distributions of current-density were calculated. Voltages in the modeled medium were calculated, and activation patterns of a model nerve fiber around the tip of each needle were estimated using the activating function. Results Maximum current density on the exposed-tip needle occurred along the edge of the distal tip; the distal edge was 1.7 times larger than the side edges and 3.5 times larger than the proximal edge. Conversely, maximum current density occurred along the proximal edge of the insulated-tip Tuohy opening; the proximal edge was 1.9 times larger than the side edges of the opening and 3.5 times larger than the distal edge of the opening. Voltages generated by the exposed-tip needle were larger and had a wider spatial distribution than that of the insulated-tip needle, which restricted to the area immediately adjacent to the opening. Different changes in threshold were predicted to excite a nerve fiber as the needles were rotated or advanced toward the modeled nerve. Conclusions The needles displayed different asymmetric distributions of current density and positional effects on threshold. If this analysis is validated clinically, it may prove useful in testing stimulating needles before clinical application.

Parallel Thermoelasticity Optimization of 3-D Serpentine Cooling Passages in Turbine Blades

2003 ◽  
Author(s):  
Brian H. Dennis ◽  
Igor N. Egorov ◽  
Helmut Sobieczky ◽  
George S. Dulikravich ◽  
Shinobu Yoshimura
Keyword(s):  
Thickness Distribution ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Parallel Computer ◽  
Surface Patch ◽  
Maximum Temperature ◽  
Convective Boundary ◽  
Element Analysis ◽  
Design Algorithm ◽  
Minimum Number

An automatic design algorithm for parametric shape optimization of three-dimensional cooling passages inside axial gas turbine blades has been developed. Smooth serpentine passage configurations were considered. The geometry of the blade and the internal serpentine cooling passages were parameterized using surface patch analytic formulation, which provides very high degree of flexibility, second order smoothness and a minimum number of parameters. The design variable set defines the geometry of the turbine blade coolant passage including blade wall thickness distribution and blade internal strut configurations. A parallel three-dimensional thermoelasticity finite element analysis (FEA) code from the ADVENTURE project at the University of Tokyo was used to perform automatic thermal and stress analysis of different blade configurations. The same code can also analyze nonlinear (large/plastic deformation) thermoelasticity problems for complex 3-D configurations. Convective boundary conditions were used for the heat conduction analysis to approximate the presence of internal and external fluid flow. The objective of the optimization was to make stresses throughout the blade as uniform as possible. Constraints were that the maximum temperature and stress at any point in the blade were less than the maximum allowable values. A robust semi-stochastic constrained optimizer and a parallel genetic algorithm were used to solve this problem while running on an inexpensive distributed memory parallel computer.

On-State and Switching Performance of High-Voltage 15 – 20 kV 4H-SiC DMOSFETs and IGBTs

2008 ◽  
Vol 600-603 ◽  
pp. 1143-1146 ◽  
Author(s):  
Tomohiro Tamaki ◽  
Ginger G. Walden ◽  
Yang Sui ◽  
James A. Cooper
Keyword(s):  
High Voltage ◽  
Current Density ◽  
Power Dissipation ◽  
Three Dimensional ◽  
Total Power ◽  
Switching Frequency ◽  
Dimensional Parameter ◽  
Switching Performance ◽  
Blocking Voltage ◽  
Maximum Current

We compare the on-state and switching performance of high-voltage 4H-SiC n-channel DMOSFETs and p-channel IGBTs within a three-dimensional parameter space defined by blocking voltage, switching frequency, and current density. We determine the maximum current density each device can carry at a given switching frequency, such that the total power dissipation is 300 W/cm2. The IGBT current depends strongly on lifetime in the NPT buffer layer, and only weakly on lifetime in the drift layer. The MOSFET current is essentially independent of frequency.

scholarly journals Comparative Analysis of Bulge Deformation between 2D and 3D Finite Element Models

2014 ◽  
Vol 6 ◽  
pp. 942719 ◽  
Author(s):  
Qin Qin ◽  
Shu Shang ◽  
Diping Wu ◽  
Yong Zang
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Solidification Process ◽  
Coupling Model ◽  
Thermomechanical Coupling ◽  
Dimensional Model ◽  
Analysis Model ◽  
Element Analysis ◽  
Temperature Distributions ◽  
Slab Temperature

Bulge deformation of the slab is one of the main factors that affect slab quality in continuous casting. This paper describes an investigation into bulge deformation using ABAQUS to model the solidification process. A three-dimensional finite element analysis model of the slab solidification process has been first established because the bulge deformation is closely related to slab temperature distributions. Based on slab temperature distributions, a three-dimensional thermomechanical coupling model including the slab, the rollers, and the dynamic contact between them has also been constructed and applied to a case study. The thermomechanical coupling model produces outputs such as the rules of bulge deformation. Moreover, the three-dimensional model has been compared with a two-dimensional model to discuss the differences between the two models in calculating the bulge deformation. The results show that the platform zone exists in the wide side of the slab and the bulge deformation is affected strongly by the ratio of width-to-thickness. The indications are also that the difference of the bulge deformation for the two modeling ways is little when the ratio of width-to-thickness is larger than six.

Self-Heating in Monolith and U-Shape Microcantilever Hotplates

2011 ◽  
Vol 120 ◽  
pp. 218-221
Author(s):  
M. Z. Ansari ◽  
Won Jun Choi ◽  
Ming Yu Lee ◽  
Chong Du Cho
Keyword(s):  
Maximum Temperature ◽  
Uniform Temperature ◽  
Analysis Software ◽  
Element Analysis ◽  
Self Heating ◽  
Temperature Distributions ◽  
Operating Environments ◽  
Uniform Temperature Field ◽  
Similar Temperature ◽  
P Type

Microcantilever hotplates use the self-heating phenomenon to achieve the required large, uniform temperature field or the cantilever-tip movement. The present study investigates the effect of self-heating on temperature and its distribution in microcantilever hotplates in monolith and u-shape configuration with different substrate materials, operating environments and applied voltages. The cantilevers are made of Si and SiO2 with a p-type Si resistor embedded. The cantilevers are operated in air and water at different applied voltages. The numerical analysis uses finite element analysis software ANSYS Multiphysics. Results show that monolith and u-shape cantilevers have similar temperature distributions, but the maximum temperature values in u-shape cantilever are higher.

Optimization of a Large Number of Coolant Passages Located Close to the Surface of a Turbine Blade

2003 ◽  
Author(s):  
Brian H. Dennis ◽  
Igor N. Egorov ◽  
George S. Dulikravich ◽  
Shinobu Yoshimura
Keyword(s):  
Three Dimensional ◽  
Circular Cross Section ◽  
Parallel Computer ◽  
Maximum Temperature ◽  
Element Analysis ◽  
Airfoil Surface ◽  
Hot Gas ◽  
Turbine Vane ◽  
Convection Boundary ◽  
Internally Cooled

A constrained optimization of locations and discrete radii of a large number of small circular cross-section straight-through coolant flow passages in internally cooled gas turbine vane was developed. The objective of the optimization was minimization of the integrated surface heat flux penetrating the airfoil thus indirectly minimizing the amount of coolant needed for the removal of this heat. Constraints were that the maximum temperature of any point in the vane is less than the maximum specified value and that the distances between any two holes or between any hole and the airfoil surface are greater than the minimum specified value. A configuration with maximum of 30 passages was considered. The presence of external hot gas and internal coolant was approximated by using convection boundary conditions for the heat conduction analysis. A parallel three-dimensional thermoelasticity finite element analysis (FEA) code from the ADVENTURE project at University of Tokyo was used to perform automatic thermal analysis of different vane configurations. A robust semi-stochastic constrained optimizer and a parallel genetic algorithm (PGA) were used to solve this problem using an inexpensive distributed memory parallel computer.

Simulation of the Effect of Dielectric Air Gaps on Interconnect Reliability

1997 ◽  
Vol 473 ◽  
Author(s):  
L. C. Bassman ◽  
R. P. Vinci ◽  
B. P. Shieh ◽  
D.-K. Kim ◽  
J. P. McVittie ◽  
...  
Keyword(s):  
Time To Failure ◽  
Element Analysis ◽  
Circuit Performance ◽  
Air Gaps ◽  
Interconnect Reliability ◽  
Improved Performance ◽  
Modeling Strategy ◽  
Interconnect Lines ◽  
Mean Time ◽  
Transmission Speed

ABSTRACTWe present a modeling strategy for assessing the reliability cost for improved performance from modified interconnect structures. We have studied air gaps which have been deliberately introduced in the passivation between aluminum interconnect lines as a means for increasing transmission speed by decreasing dielectric capacitance. The models allow examination of tradeoffs between improved circuit performance and decreased reliability due to dielectric cracking. Stresses in the dielectric due to electromigration in the metal were modeled using finite element analysis. These stresses were used to compute an estimate of the mean time to failure relative to the case with no air gap using an electromigration failure model from MIT.

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