Compact Thermal Modeling Methodology for Active and Thermal Bumps in 3D Microelectronic Packages

2015 ◽  
Author(s):  
Arnab Choudhury ◽  
Shrenik Kothari ◽  
Nayandeep Mahanta ◽  
Hemanth Dhavaleswarapu ◽  
Je-Young Chang
Keyword(s):  
Thermal Conductivity ◽  
Effective Conductivity ◽  
Volumetric Method ◽  
Computational Time ◽  
Compact Modeling ◽  
Accurate Estimation ◽  
Modeling Methodology ◽  
Microelectronic Packages ◽  
Compact Thermal Modeling ◽  
Effective Design

Accurate estimation of the thermal conductivity of logic-memory and memory-memory interfaces, between stacked die in 3D microelectronic packages, is key to effective design and early estimates of performance and reliability. Typically, interconnect layers contain hundreds to a few thousands of bumps. Hence lumped/compact modeling of this interfacial layer is essential to reduce computational time and complexity. The typical approach to this lumped modeling is to estimate the effective conductivity of the layer by assuming the bumps and underfill regions can be modelled as parallel thermal resistances (referred to as the volumetric method). This work demonstrates that the volumetric method can significantly underpredict 3D stack thermal resistance and junction temperatures. An alternative method-referred to as the single bump method-of estimation of the thermal conductivity of interconnect layers in 3D stacked-die packages is presented. Studies demonstrate that the proposed single bump method captures the heat transfer in these interfaces accurately. Validation of the single bump modeling is presented by comparing the single bump and volumetric methods with fully discretized models. This comparison also demonstrates that the prevalent volumetric method overestimates the effective thermal conductivity of the interface, while the single bump approach results in more accurate assessment of 3D stack resistance.

The prediction of vehicle vibration transmitted to the occupant using a modular transfer matrix

2021 ◽  
pp. 107754632199759
Author(s):  
Jianchun Yao ◽  
Mohammad Fard ◽  
John L Davy ◽  
Kazuhito Kato
Keyword(s):  
Finite Element ◽  
Transfer Matrix ◽  
Dynamic Performance ◽  
Complex Structure ◽  
Vehicle Body ◽  
Computational Time ◽  
Accurate Estimation ◽  
Finite Element Models ◽  
Transfer Matrices ◽  
Body Vibration

Industry is moving towards more data-oriented design and analyses to solve complex analytical problems. Solving complex and large finite element models is still challenging and requires high computational time and resources. Here, a modular method is presented to predict the transmission of vehicle body vibration to the occupants’ body by combining the numerical transfer matrices of the subsystems. The transfer matrices of the subsystems are presented in the form of data which is sourced from either physical tests or finite element models. The structural dynamics of the vehicle body is represented using a transfer matrix at each of the seat mounting points in three triaxial (X–Y–Z) orientations. The proposed method provides an accurate estimation of the transmission of the vehicle body vibration to the seat frame and the seated occupant. This method allows the combination of conventional finite element analytical model data and the experimental data of subsystems to accurately predict the dynamic performance of the complex structure. The numerical transfer matrices can also be the subject of machine learning for various applications such as for the prediction of the vibration discomfort of the occupant with different seat and foam designs and with different physical characteristics of the occupant body.

CPI Stress Induced Carrier Mobility Shift in Advanced Silicon Nodes

2016 ◽  
Author(s):  
Valeriy Sukharev ◽  
Jun-Ho Choy ◽  
Armen Kteyan ◽  
Henrik Hovsepyan ◽  
Uwe Muehle ◽  
...  
Keyword(s):  
Electrical Characterization ◽  
Compact Modeling ◽  
Electrical Characteristics ◽  
Mobility Shift ◽  
Physical Strain ◽  
Multi Scale ◽  
Modeling Methodology ◽  
Simulation Based Design ◽  
Simulation Based ◽  
Final Design

Potential challenges with managing mechanical stress and the consequent effects on device performance for advanced 3D IC technologies are outlined. The growing need for a simulation-based design verification flow capable of analyzing and detecting across-die out-of-spec stress-induced variations in MOSFET/FinFET electrical characteristics is highlighted. A physics-based compact modeling methodology for multi-scale simulation of all contributing components of stress induced variability is described. A simulation flow that provides an interface between layout formats (GDS II, OASIS), and FEA-based package-scale tools, is also developed. This tool, can be used to optimize the floorplan for different circuits and packaging technologies, and/or for the final design signoff, for all stress induced phenomena. Finally, a calibration technique based on fitting to measured electrical characterization data is presented, along with correlation of the electrical characteristics to direct physical strain measurements.

Compact Modeling of a Telecommunication Cabinet

2008 ◽  
Author(s):  
Aalok Trivedi ◽  
Dereje Agonafer ◽  
Deepak Sivanandan ◽  
Mark Hendrix ◽  
Akbar Sahrapour
Keyword(s):  
Heat Exchanger ◽  
Computation Time ◽  
Time Frame ◽  
Thermal Design ◽  
Compact Model ◽  
Computational Time ◽  
Compact Modeling ◽  
Thermal System ◽  
Mesh Density ◽  
Product Test

Computational Fluid Dynamics (CFD) is widely used in the telecommunication industry to validate experimental data and obtain both qualitative and quantitative results during product development. A typical outdoor telecommunications cabinet requires the modeling of a large number of components in order to perform the required air flow and thermal design. Among these components, the heat exchanger is the most critical to thermal performance. The cabinet heat exchanger and other thermal components make up a complex thermal system. This thermal system must be characterized and optimized in a short time frame to support time-to-market requirements. CFD techniques allow for completing system thermal optimization long before product test data can be available. However, the computational model of the complex thermal system leads to a large mesh count and corresponding lengthy computational times. The objective of this paper is to present an overview of techniques to minimize the computational time for complex designs such as a heat exchanger used in telecommunication cabinets. The discussion herein presents the concepts which lead to developing a compact model of the heat exchanger, reducing the mesh count and thereby the computation time, without compromising the acceptability of the results. The model can be further simplified by identifying the components significantly affecting the physics of the problem and eliminating components that will not adversely affect either the fluid mechanics or heat transfer. This will further reduce the mesh density. Compact modeling, selective meshing, and replacing sub-components with simplified equivalent models all help reduce the overall model size. The model thus developed is compared to a benchmark case without the compact model. Given that the validity of compact models is not generalized, it is expected that this methodology can address this particular class of problems in telecommunications systems. The CFD code FLOTHERM™ by Flomerics is used to carry out the analysis.

Bounds on the Transverse Effective Conductivity of Computer-Generated Fiber Composites

1982 ◽  
Vol 49 (2) ◽  
pp. 319-326 ◽  
Author(s):  
J. J. McCoy
Keyword(s):  
Thermal Conductivity ◽  
Effective Conductivity ◽  
Fiber Composite ◽  
Effective Property ◽  
Fiber Composites ◽  
Area Fraction ◽  
Fiber Area ◽  
Single Body ◽  
Transverse Thermal Conductivity ◽  
Dilute Suspension

Using trial functions that are motivated by single-body calculations, we have derived bounds on the effective transverse thermal conductivity of a fiber composite. These bounds incorporate both fiber area fraction information and some information of the configurational statistics. Simplified expressions for the bounds are obtained for the limits of widely differing conductivity values for the constitutent phases, and of a dilute suspension. The bounds are made specific for a given computer-generated fiber composite and these specific bounds are compared with the best available bounds that require area fraction information alone. The conclusions reached are that configuration statistics are significant for effective property calculations for moderately dense composites for component conductivity values that differ by some one to two orders of magnitude, or greater. Further, the bounds based on the single-body calculation are reasonably close for component conductivity values that differ by some two orders of magnitude, or less.

Computational Evaluation of Effective Conductivity of Particulate Composites with Imperfect Interfaces

2009 ◽  
Vol 631-632 ◽  
pp. 35-40
Author(s):  
M. Zhang ◽  
Peng Cheng Zhai ◽  
Qing Jie Zhang
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Effective Properties ◽  
Effective Conductivity ◽  
Three Dimensional ◽  
Particulate Composite ◽  
Imperfect Interface ◽  
Particulate Composites ◽  
Imperfect Interfaces ◽  
Volume Fractions

This paper is aimed to numerically evaluate the effective thermal conductivity of randomly distributed spherical particle composite with imperfect interface between the constituents. A numerical homogenization technique based on the finite element method (FEM) with representative volume element (RVE) was used to evaluate the effective properties with periodic boundary conditions. Modified random sequential adsorption algorithm (RSA) is applied to generate the three dimensional RVE models of randomly distributed spheres of identical size with the volume fractions up to 50%. Several investigations have been conducted to estimate the influence of the imperfect interfaces on the effective conductivity of particulate composite. Numerical results reveal that for the given composite, due to the existence of an interfacial thermal barrier resistance, the effective thermal conductivity depends not only on the volume fractions of the particle but on the particle size.

scholarly journals Effective conductivity of isotropic composite with Kapitza thermal resistance

2018 ◽  
Author(s):  
Kien Trung Nguyen ◽  
Luat Van Nguyen ◽  
Chinh Duc Pham
Keyword(s):  
Thermal Conductivity ◽  
Thermal Resistance ◽  
Effective Thermal Conductivity ◽  
Effective Conductivity ◽  
Imperfect Interface ◽  
Simple Method ◽  
Isotropic Composite ◽  
Equivalent Inclusion

A simple method is introduced for computing the effective conductivity of isotropic composite with imperfect interface. Based on the doubly-coated circle assemblage model, one can determine the effective thermal conductivity of the composite. The application of this model to the composite with imperfect interface of the Kapitza's type is proposed. The results obtained were compared with the FFT simulation and the equivalent inclusion approximation in 2D show the effectiveness of the methods.

scholarly journals Self-Organized Model Fitting Method for Railway Structures Monitoring Using LiDAR Point Cloud

2020 ◽  
Vol 12 (22) ◽  
pp. 3702
Author(s):  
Amila Karunathilake ◽  
Ryohei Honma ◽  
Yasuhito Niina
Keyword(s):  
Point Cloud ◽  
Spatial Location ◽  
Railway Track ◽  
Computational Time ◽  
Accurate Estimation ◽  
Long Distance ◽  
Rail Track ◽  
Railway Line ◽  
Point Density ◽  
Vertical Slice

Mobile laser scanning (MLS) has been successfully used for infrastructure monitoring apt to its fine accuracy and higher point density, which is favorable for object reconstruction. The massive data size, computational time, wider spatial distribution and feature extraction become a challenging task for 3D point data processing with MLS point cloud receives from terrestrial structures such as buildings, roads and railway tracks. In this paper, we propose a new approach to detect the structures in-line with railway track geometry such as railway crossings, turnouts and quantitatively estimate their dimensions and spatial location by iteratively applying a vertical slice to point cloud data for long distance laser measurement. The rectangular vertical slices were defined and their boundary coordinates were estimated based on a geometrical method. Estimated vertical slice boundaries were iteratively used to evaluate the point density of each vertical slice along with a cross-track direction of the railway line. Those point densities were further analyzed to detect the railway line track objects by their shape and spatial location along with the rail bed. Herein, the survey dataset is used as a dictionary to preidentify the spatial location of the object and then as an accurate estimation for the rail-track, by estimating the gauge corner (GC) from dense point cloud. The proposed method has shown a significant improvement in the rail-track extraction process, which becomes a challenge for existing remote sensing technologies. This adaptive object detection method can be used to identify the railway track structures prior to the railway track extraction, which allows in finding the GC position precisely. Further, it is based on the parallelism of the railway track, which is distinct from conventional railway track extraction methods. Therefore it does not require any inertial measurements along with the MLS survey and can be applied with less background information of the observed MLS point cloud. The proposed algorithm was tested for the MLS data set acquired during the pilot project collaborated with West Japan Railway Company. The results indicate 100% accuracy for railway structure detection and enhance the GC extraction for railway structure monitoring.

Compact Modeling of Unshrouded Plate Fin Heat Sinks

2003 ◽  
Author(s):  
Sridhar Narasimhan ◽  
Avram Bar-Cohen
Keyword(s):  
Thermal Conductivity ◽  
Pressure Drop ◽  
Effective Thermal Conductivity ◽  
Heat Sink ◽  
Heat Sinks ◽  
Compact Modeling ◽  
Base Temperature ◽  
Computational Domain ◽  
Porous Block ◽  
Compact Models

The present work considers the compact modeling of unshrouded parallel plate heat sinks in laminar forced convection. The computational domain includes three heat sinks in series, cooled by an intake fan. The two upstream heat sinks are represented as “porous blocks”, each with an effective thermal conductivity and a pressure loss coefficient, while the downstream heat sink, assumed to be the component requiring the most accurate characterization, is modeled in detail. A large parametric space covering three typical heat sink geometries, as well as a range of common inlet velocities, separation distances between the heat sinks, and bypass clearances is considered in the development and evaluation of the compact models. The current study uses a boundary layer-based methodology, accounting for both the viscous dissipation and form drag losses, to determine the pressure drop characteristics, and an effective conductivity methodology, using a flow bypass model and Nusselt number correlation, to determine the effective thermal conductivity, for the porous block representation of the heat sink. The results indicate that the introduction of compact heat sinks has little influence on the pressure drop of the critical heat sink. Good agreement in pressure drops, typically in the range of 5%, is also obtained between “detailed” heat sink models and their corresponding porous block representation. The introduction of the compact models is found to have little influence (typically less than 1°C) on the base temperature of the critical heat sinks. For the compact heat sinks, the agreement is again within a typical difference of 5% in thermal resistance. Dramatic improvements were observed in the mesh count (factor > 10X) and solution time (factor >20X) required to achieve a high-fidelity simulation of the velocity, pressure, and temperature fields.

Actively heated fiber optics based thermal response test

2021 ◽  
Author(s):  
Kai Gu ◽  
Bo Zhang ◽  
Bin Shi ◽  
Chun Liu ◽  
Peter Bayer ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Fiber Optics ◽  
Geothermal Energy ◽  
Thermal Response ◽  
Clean Energy ◽  
Accurate Estimation ◽  
Thermal Response Test ◽  
Investigation Method ◽  
Response Test ◽  
Shallow Geothermal Energy

<p>In the pursuit of sustainable development and the mitigation of climate change, shallow geothermal energy has been widely recognized as a type of clean energy with great potential. Accurate estimation of thermal ground properties is needed to optimally apply shallow geothermal energy technologies, which are of growing importance for the heating and cooling sector. A special challenge is posed by the often significant heterogeneity and variability of the geological media at a site.</p><p>As an innovative investigation method, we focus on the actively heated fiber optics-based thermal response test (ATRT) and its application in a borehole in Changzhou, China. A copper mesh heated optical cable (CMHC), which both serves as a heating source and a temperature sensing cable, was applied in the borehole. By inducing the electric current to the cable at a relatively low power of 26 W/m, the in-situ heating process was recorded at high depth resolution. This information serves to infer the thermal conductivity distribution along the borehole. The presented field experience reveals that the temperature rise in the early phase of the test should not be used due to initial heat accumulation caused by the outer jacket of the CMHC. The comparison of these results with those of a conventional thermal response test (TRT) and a distributed thermal response test (DTRT) in the same borehole confirmed that the ATRT result is reliable (with a difference less than 5% and 1%, respectively). Most importantly, this novel method affords much less energy and testing time.</p><p>Additionally, to estimate the uncertainty and limits associated with the method, a 2D axisymmetric numerical model based on COMSOL Multiphysics® has been developed. The results indicate that an accurate calculated thermal conductivity requires heating duration to be in the range of 90~400 min considering test efficiency and cost. Our study promotes ATRT as an advanced geothermal field investigation method and it also extends the applicability of the thermal response test as a downhole tool for measurement of soil hydraulic properties.</p>

Sign in / Sign up

Export Citation Format

Share Document