Thermo-Mechanical Reliability of Through Silicon Vias (TSVs) and Solder Interconnects in 3-Dimensional Integrated Circuits

2009 ◽  
Author(s):  
Leila J. Ladani ◽  
Omar Rodriguez
Keyword(s):  
Solder Joints ◽  
Silicon Layer ◽  
Copper Interconnects ◽  
Influential Factor ◽  
Design Parameters ◽  
Temperature Cycle ◽  
Optimum Level ◽  
3D Ic ◽  
3 Dimensional ◽  
The Impact

3-dimensional integrated circuit (3D IC) is a promising technology in today’s IC packaging industry. Since the technology is in infancy stages, many aspects of this technology are still under heavy investigation. Reliability of through silicon via (TSV) interconnects and interlayer bonding between the silicon layers are issues that become more complicated in 3D ICs due to complexity of the architecture and miniaturized interconnects. Optimizing design of these devices is essential in order to avoid short fatigue life of interconnects. This manuscript addresses the impact of design parameters such as die thickness, TSV diameter, TSV pitch, underfill thickness and underfill properties on thermo-mechanical durability of Direct Chip Attach (DCA) solder joints and TSV interconnects used in a 3D IC packages. A design was proposed where DCA is used to connect 4 layers of ICs and TSVs are used to connect the active layer of the dies to the second silicon layer. Solder joints, as small as 50-micron diameter, were used to attach silicon layers. A numerical experiment is designed to vary design parameters at 3 levels using L9 ortagonal array. A 3-dimensional model of the package was built and model was solved under an accelerated temperature cycle loading. Solder is considered as visco-plastic material and copper interconnects are assumed to follow bilinear isotropic hardening behavior. Two continuum damage models, energy partitioning and Coffin-Manson models, were used to assess the number of cycles to failure for solder joints and TSV copper interconnects respectively. Minitab software was used to analyze the result of experiment. The most influential factors on durability of solder interconnect are found to be underfill properties and height. However, the most influential factor on TSV durability is found to be TSV diameter. A non-linear response was observed for TSV pitch and diameter indicating that the optimum level may be in the range selected.

A Methodology for Chip - Package Interaction (CPI) Modeling in 3D IC Structures

2012 ◽  
Vol 2012 (DPC) ◽  
pp. 001373-001393 ◽  
Author(s):  
Karthikeyan Dhandapani ◽  
Ahmer Syed ◽  
Wei Lin ◽  
Mark Nakamoto ◽  
Wei Zhao ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Silicon Layer ◽  
Dissimilar Materials ◽  
Electrical Performance ◽  
Assembly Process ◽  
3D Ic ◽  
Modeling Approach ◽  
Level Model ◽  
The Impact ◽  
Modeling Flow

Chip-Package Interaction (CPI) is a significant concern for modern electronic devices and this concern is magnified for 3D Stacked IC. Hard bumps, soft dielectrics, thin die and complex geometries of the stacked die require an ability to model and evaluate the interactions and risks. In packaged IC, dissimilar materials along with the thermal history during the assembly process results in significant residual stresses. These stresses can impact process yields, reliability and die electrical performance. Examples of these effects are ball cracking, ILD/ELK cracking or delamination and shifts in the behavior of sensitive devices such as transistors in analog circuits. Traditionally modeling and evaluation of these risks have been handled by different groups/companies (foundry, OSAT, Fabless Device Mfg) and have been hindered by the difficulty of using different tools and more importantly collaborating without revealing proprietary models and process information/recipes. In this paper we present a modeling flow which incorporates a seamless interface between the tools traditionally used for both package and silicon modeling. This is accomplished by utilizing Boundary Conditions (BC's) to act as a hand-off between the two simulation tools. A package level modeling approach is developed incorporating package assembly processes to predict residual stresses at the end of package assembly process. This package level simulator uses a nested sub-modeling approach for detailed extraction of stresses at different locations within BEOL layers of die, u-bumps, and C4 bumps from package level simulations. Additionally, it allows complete flexibility in selecting boundaries at chip-package interface and then the extraction of BC's necessary for die and transistor level simulations. These boundaries for Chip-Package Interaction are selected by the device manufacturer and the output from this simulation is fed into device level simulations. To provide flexibility for the user and to attain quick turnaround time, a web hosted interface is enabled to run package simulations online. The capabilities of this modeling approach are demonstrated by studying the impact of design and material parameters on stresses at various interconnect structures constituting a typical 3D IC stack package. An example of active silicon layer stress correlation from package level model and die-level model will be presented, thus validating this overall modeling flow.

Design of Experiments in Ball Grid Array Thermal Fatigue Life Tests

2002 ◽  
Author(s):  
T. E. Wong ◽  
C. Y. Lau ◽  
L. A. Kachatorian ◽  
H. S. Fenger ◽  
I. C. Chen
Keyword(s):  
Fatigue Life ◽  
Thermal Fatigue ◽  
Solder Joints ◽  
Ball Grid Array ◽  
Temperature Cycling ◽  
Design Parameters ◽  
Physical Analysis ◽  
Printed Wiring Board ◽  
Thermal Fatigue Life ◽  
The Impact

The objective of the present study is to evaluate the impact of electronic packaging design/manufacturing process parameters on the thermal fatigue life of ball grid array (BGA) solder joints. The four selected parameters are BGA under-fill materials, conformal coating, solder pad sizes on printed wiring board, and BGA rework, with each having either two or three levels of variation. A test vehicle (TV), on which various sizes of BGA daisy-chained packages are soldered, is first designed and fabricated, and then subjected to temperature cycling (−55°C to +125°C) with continuous monitoring of solder joint integrity. The total of 15 experimental cases is used in the present study. Based on monitored results, a destructive physical analysis is conducted to further isolate the failure locations and determine the failure mechanisms of the solder joints. Test results indicate that the influence of these design parameters on fatigue life is dependent on the particular package, in some instances improving the fatigue life tenfold.

Reliability Analysis of Solder Joints on Rigid-Flexible PCB for MEMS Pressure Sensors Under Combined Temperature Cycle and Vibration Loads with Continuously Monitored Electrical Signals

2021 ◽  
Author(s):  
Xiaoping Wang ◽  
Jun Yang ◽  
Xiaogang Liu ◽  
Panpan Zheng ◽  
Qinglin Song ◽  
...  
Keyword(s):  
Finite Element ◽  
Solder Joint ◽  
Solder Joints ◽  
Pressure Sensors ◽  
Experimental Results ◽  
Circuit Board ◽  
Design Parameters ◽  
Temperature Cycle ◽  
Electrical Signals ◽  
Flexible Pcb

Abstract The reliability of lead-free solder joints on flexible PCB has created significant new challenges in the industry, especially in automotive electronics, and possibly for future wearable electronics.In this paper, the submodeling technique was used to construct the finite element model of the rigid-flexible printed circuit board (rigid-flexible PCB) for a MEMS pressure sensor subjected to combined temperature cycle and random vibration loadings. During all the experiments, the electrical signals of each specimen were continuously monitored using an event detector. One advantage of this method is that any individual soldering interconnect failure will result in the diagnostic signal of the circuit, which could be detected in real time. The influence of vibration frequency and acceleration on the vibration fatigue life of solid joints was investigated.The research results are helpful to effectively characterize the performance of the MEMS sensors under combine thermal cycling test and vibration test. Two kinds of land shapes and two kinds of PCB assemblies were selected. The solder joint is sliced and the crack on the cross section of solder joint was observed. Results of finite element modeling analysis were consistent with the experimental results. Two design parameters have been identified in our research as being important to soldering usage in automotive environments: pad type (teardrop vs. non-teardrop) and pad size (big vs. small, matching size for Cu-wire and pad). Experimental results also showed that the solder joint with big land shape presented a relatively good thermal fatigue resistance.

Design of a Robust Memristive Spiking Neuromorphic System with Unsupervised Learning in Hardware

2021 ◽  
Vol 17 (4) ◽  
pp. 1-26
Author(s):  
Md Musabbir Adnan ◽  
Sagarvarma Sayyaparaju ◽  
Samuel D. Brown ◽  
Mst Shamim Ara Shawkat ◽  
Catherine D. Schuman ◽  
...  
Keyword(s):  
Unsupervised Learning ◽  
Recognition Task ◽  
Single Layer ◽  
Process Variations ◽  
Spike Timing ◽  
System Level ◽  
Design Parameters ◽  
Digital Pulse ◽  
Neuromorphic System ◽  
The Impact

Spiking neural networks (SNN) offer a power efficient, biologically plausible learning paradigm by encoding information into spikes. The discovery of the memristor has accelerated the progress of spiking neuromorphic systems, as the intrinsic plasticity of the device makes it an ideal candidate to mimic a biological synapse. Despite providing a nanoscale form factor, non-volatility, and low-power operation, memristors suffer from device-level non-idealities, which impact system-level performance. To address these issues, this article presents a memristive crossbar-based neuromorphic system using unsupervised learning with twin-memristor synapses, fully digital pulse width modulated spike-timing-dependent plasticity, and homeostasis neurons. The implemented single-layer SNN was applied to a pattern-recognition task of classifying handwritten-digits. The performance of the system was analyzed by varying design parameters such as number of training epochs, neurons, and capacitors. Furthermore, the impact of memristor device non-idealities, such as device-switching mismatch, aging, failure, and process variations, were investigated and the resilience of the proposed system was demonstrated.

Making Up 3D Bodies

2021 ◽  
Vol 4 (2) ◽  
pp. 1-9
Author(s):  
Kiona Hagen Niehaus ◽  
Rebecca Fiebrink
Keyword(s):  
Software Tool ◽  
The Body ◽  
Design Parameters ◽  
Artistic Practice ◽  
Human Form ◽  
Modeling Systems ◽  
Exploratory Approach ◽  
Disability Status ◽  
High Level ◽  
The Impact

This paper describes the process of developing a software tool for digital artistic exploration of 3D human figures. Previously available software for modeling mesh-based 3D human figures restricts user output based on normative assumptions about the form that a body might take, particularly in terms of gender, race, and disability status, which are reinforced by ubiquitous use of range-limited sliders mapped to singular high-level design parameters. CreatorCustom, the software prototype created during this research, is designed to foreground an exploratory approach to modeling 3D human bodies, treating the digital body as a sculptural landscape rather than a presupposed form for rote technical representation. Building on prior research into serendipity in Human-Computer Interaction and 3D modeling systems for users at various levels of proficiency, among other areas, this research comprises two qualitative studies and investigation of the impact on the first author's artistic practice. Study 1 uses interviews and practice sessions to explore the practices of six queer artists working with the body and the language, materials, and actions they use in their practice; these then informed the design of the software tool. Study 2 investigates the usability, creativity support, and bodily implications of the software when used by thirteen artists in a workshop. These studies reveal the importance of exploration and unexpectedness in artistic practice, and a desire for experimental digital approaches to the human form.

scholarly journals Simulation Tests of a Cow Milking Machine—Analysis of Design Parameters

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1358
Author(s):  
Ewa Golisz ◽  
Adam Kupczyk ◽  
Maria Majkowska ◽  
Jędrzej Trajer
Keyword(s):  
Mathematical Model ◽  
Simplified Model ◽  
Design Parameters ◽  
Degree Polynomial ◽  
Fourth Degree ◽  
Local Loss ◽  
Linear Drag ◽  
Milking Machine ◽  
Machine Analysis ◽  
The Impact

The objective of this paper was to create a mathematical model of vacuum drops in a form that enables the testing of the impact of design parameters of a milking cluster on the values of vacuum drops in the claw. Simulation tests of the milking cluster were conducted, with the use of a simplified model of vacuum drops in the form of a fourth-degree polynomial. Sensitivity analysis and a simulation of a model with a simplified structure of vacuum drops in the claw were carried out. As a result, the impact of the milking machine’s design parameters on the milking process could be analysed. The results showed that a change in the local loss and linear drag coefficient in the long milk duct will have a lower impact on vacuum drops if a smaller flux of inlet air, a higher head of the air/liquid mix, and a higher diameter of the long milk tube are used.

Computational Analysis of Olfactory Airspace in Patients With Unilateral Cleft Lip Nasal Deformity

2020 ◽  
pp. 105566562098275
Author(s):  
Reanna Shah ◽  
Jeffrey R. Marcus ◽  
Dennis O. Frank-Ito
Keyword(s):  
Cleft Lip ◽  
Computational Analysis ◽  
Normal Subjects ◽  
Nasal Deformity ◽  
Normal Anatomy ◽  
3 Dimensional ◽  
Computed Tomography Images ◽  
High Prevalence ◽  
Dimensional Reconstruction ◽  
The Impact

Objectives: To evaluate the magnitude of olfactory recess opacity in patients with unilateral cleft lip nasal deformity (uCLND). Design: Subject-specific 3-dimensional reconstruction of the nasal airway anatomy was created from computed tomography images in 11 (4 males and 7 females) subjects with uCLND and 7 (3 males, and 4 females) normal subjects. The volume and surface area of each subject’s unilateral and bilateral olfactory airspace was quantified to assess the impact of opacification. Qualitatively speaking, patients with 75% to 100% olfactory recess opacification were classified as extreme, 50% to 75% as severe, 25% to 50% as moderate, and 0% to 25% as mild. Results: Of the 11 subjects with uCLND, 5 (45%) were classified as having extreme olfactory recess opacification, 3 (27%) subjects had severe opacification, and 3 (27%) subjects had moderate opacification. Mean (±SD) bilateral olfactory recess volume was significantly greater in normal subjects than in subjects with uCLND (0.9668 cm3 ± 0.4061 cm3 vs 0.3426 cm3 ± 0.1316 cm3; P < .001). Furthermore, unilateral olfactory airspace volumes for the cleft and non-cleft sides in subjects with uCLND were considerably less than unilateral olfactory volume in subjects with normal anatomy (uCLND cleft side = 0.1623 cm3 ± 0.0933 cm3; uCLND non-cleft side = 0.1803 cm3 ± 0.0938 cm3; normal = 0.4834 cm3 ± 0.2328 cm3; P < .001). Conclusions: Our findings indicate a high prevalence of olfactory recess opacification among subjects with uCLND when compared to subjects with normal anatomy. The majority of subjects with uCLND had extreme olfactory recess opacity, which will likely influence their sense of smell.

scholarly journals It’s the Weather: Quantifying the Impact of Weather on Retail Sales

2021 ◽  
Author(s):  
Natalie Rose ◽  
Les Dolega
Keyword(s):  
Weather Condition ◽  
Weather Conditions ◽  
Influential Factor ◽  
Retail Sector ◽  
Retail Sales ◽  
Weather Impact ◽  
High Street ◽  
Sector Decision ◽  
The Impact ◽  
The Relationship

AbstractThe weather is considered as an influential factor on consumer purchasing behaviours and plays a significant role in many aspects of retail sector decision making. As a result, better understanding of the magnitude and nature of the influence of variable UK weather conditions can be beneficial to many retailers and other stakeholders. This study addresses the dearth of research in this area by quantifying the relationship between different weather conditions and trading outcomes. By employing comprehensive daily sales data for a major high street retailer with over 2000 stores across England and adopting a random forest methodology, the study quantifies the influence of various weather conditions on daily retail sales. Results indicate that weather impact is greatest in the summer and spring months and that wind is consistently found to be the most influential weather condition. The top five most weather-dependent categories cover a range of different product types, with health foods emerging as the most susceptible to the weather. Also, sales from out-of-town stores show a far more complex relationship with the weather than those from traditional high street stores with the regions London and the South East experiencing the greatest levels of influence. Various implications of these findings for retail stakeholders are discussed and the scope for further research outlined.

scholarly journals A New Approach for Design Optimization and Parametric Analysis of Symmetric Compound Parabolic Concentrator for Photovoltaic Applications

2021 ◽  
Vol 13 (9) ◽  
pp. 4606
Author(s):  
Faisal Masood ◽  
Perumal Nallagownden ◽  
Irraivan Elamvazuthi ◽  
Javed Akhter ◽  
Mohammad Azad Alam
Keyword(s):  
Parametric Analysis ◽  
Concentration Ratio ◽  
Synergistic Effects ◽  
Geometric Optimization ◽  
Design Parameters ◽  
Imaging Device ◽  
Compound Parabolic Concentrator ◽  
Photovoltaic Applications ◽  
Half Angle ◽  
The Impact

A compound parabolic concentrator (CPC) is a non-imaging device generally used in PV, thermal, or PV/thermal hybrid systems for the concentration of solar radiation on the target surface. This paper presents the geometric design, statistical modeling, parametric analysis, and geometric optimization of a two-dimensional low concentration symmetric compound parabolic concentrator for potential use in building-integrated and rooftop photovoltaic applications. The CPC was initially designed for a concentration ratio of “2×” and an acceptance half-angle of 30°. A MATLAB code was developed in house to provoke the CPC reflector’s profile. The height, aperture width, and concentration ratios were computed for different acceptance half-angles and receiver widths. The interdependence of optical concentration ratio and acceptance half-angle was demonstrated for a wide span of acceptance half-angles. The impact of the truncation ratio on the geometric parameters was investigated to identify the optimum truncation position. The profile of truncated CPC for different truncation positions was compared with full CPC. A detailed statistical analysis was performed to analyze the synergistic effects of independent design parameters on the responses using the response surface modeling approach. A set of optimized design parameters was obtained by establishing specified optimization criteria. A 50% truncated CPC with an acceptance half-angle of 21.58° and receiver width of 193.98 mm resulted in optimum geometric dimensions.

scholarly journals The Impact of Working Capital Management on Firm Profitability: Empirical Evidence from the Polish Listed Firms

2020 ◽  
Vol 14 (1) ◽  
pp. 9
Author(s):  
Sorin Anton ◽  
Anca Afloarei Nucu
Keyword(s):  
Empirical Evidence ◽  
Ordinary Least Squares ◽  
Optimum Level ◽  
Capital Management ◽  
Working Capital ◽  
Working Capital Management ◽  
Listed Firms ◽  
Firm Profitability ◽  
Break Even Point ◽  
The Impact

The purpose of this study is to investigate the relationship between working capital and firm profitability for a sample of 719 Polish listed firms over the period of 2007–2016. The scarcity of empirical evidence for emerging economies and the importance of working capital efficiency motivate the research on the working capital–financial performance relationship. The paper adopts a quantitative approach using different panel data techniques (ordinary least squares, fixed effects, and panel-corrected standard errors models). The empirical results report an inverted U-shape relationship between working capital level and firm profitability, meaning that working capital has a positive effect on the profitability of Polish firms to a break-even point (optimum level). After the break-even point, working capital starts to negatively affect firm profitability. The study brings theoretical and practical contributions. It extends and complements the literature on the field by highlighting new evidence on the non-linear interrelation between working capital management (WCM) and corporate performance in Poland. From the practitioners’ perspective, the results highlight the importance of WCM for firm profitability.

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