Reliability analysis of bonding wire based on stacked substrate packaging structure

2019 ◽  
Vol 2019 (1) ◽  
pp. 000603-000608
Author(s):  
Chi Zhang ◽  
Yifan Tan ◽  
Zhizhao Huang ◽  
Cai Chen ◽  
Yong Kang
Keyword(s):  
Thermal Cycling ◽  
Layer Thickness ◽  
Peak Height ◽  
Analytical Models ◽  
Bonding Wire ◽  
Module Design ◽  
Fast Switching ◽  
Calculation Results ◽  
Bonding Wires ◽  
Packaging Structure

Abstract The stacked substrate packaging technology is a new 3D power loop structure utilizing multiple layer DBC to achieve ultra-low parasitic for the fast switching SiC device. This structure has a different geometry on interconnection between chips and substrate contrasting to the conventional module design, which needs optimization on the interconnection for the reliability consideration of this new structure. Analytical models of different bonding wire shapes and DBC structures were developed to calculate the von-mise stress on each model under thermal cycling simulation. The simulation results show that the stress on bonding wire reaches minimum when welding point located at the center of the top DBC substrate and the stress decreases when DBC top copper layer thickness increases or ceramic layer thickness decreases. Moreover, bonding wires with smaller diameter, certain peak height and width show lower stress and strain. Furthermore, thermal cycling tests were done on samples with same geometries of analytical models, and the wire pull test results showed consistency with the stress calculation results which verifying the optimum wire shape and DBC structure for the stacked substrate packaging.

Critical Barriers Associated with Copper Wire

2015 ◽  
Vol 2015 (1) ◽  
pp. 000394-000398
Author(s):  
William G. Crockett
Keyword(s):  
High Reliability ◽  
Copper Wire ◽  
Automotive Electronics ◽  
Bonding Wire ◽  
Cu Alloy ◽  
Bonding Wires ◽  
Reducing Costs ◽  
Cu Bonding ◽  
Bonding Characteristics ◽  
Bare Copper

Since around 2008, the shift from Gold (Au) bonding wire to Copper (Cu) bonding wire has been taking place, full scale, with the aim of reducing costs. When compared with Au, Cu wire presents challenges in reliability and repeatable bonding characteristics in terms of chemical stability, which is required in high reliability applications. Therefore Cu wire adoption in automotive and industrial semiconductors has been limited. Conventionally the market for Cu bonding wires has been divided into two types: bare Cu wires (high purity) and Palladium coated copper (PCC) bonding wires. These wires have yet to satisfy the required characteristics for high reliability products such as industrial and automotive electronics. A new breed of alternative bonding wires has been developed to offer performance advantages for high reliability applications compared to bare copper wire and PCC wire. Cu alloy wire and Ag alloy wires continue their market introduction for advanced bonding applications, where bare Cu and PCC wires have known limitations.

Comparison of Thermal and Stress Analysis Results for a High Voltage Module Using FEA and a Quick Parametric Analysis Tool

2018 ◽  
Author(s):  
L. M. Boteler ◽  
S. M. Miner
Keyword(s):  
Stress Analysis ◽  
High Voltage ◽  
Parametric Analysis ◽  
Thermal Stresses ◽  
Analysis Tool ◽  
Element Analysis ◽  
Module Design ◽  
Fast Running ◽  
Packaging Structure ◽  
Low Order

A low order fast running parametric analysis tool, ParaPower, was used to arrive at the design for a novel high voltage module. The low order model used a 3D nodal network to calculate device temperatures and thermal stresses. The model assumed heat flux generated near the top surface of each device which is then conducted through the packaging structure and removed by convection. The temperature distribution is used to calculate thermal stresses throughout the package. This co-design modeling tool, developed for rectilinear geometries, allowed a rapid evaluation of the package temperatures and CTE induced stresses throughout the design space. However, once the final design configuration was determined a detailed finite element analysis was performed to validate the design. This paper compares the results obtained using ParaPower to the FEA, demonstrating the usefulness of the parametric analysis tool. Results for both temperature and CTE induced stress are compared. Two different stress models are evaluated. One based on the more traditional planar module design, which assumes a substantial substrate or heat spreader on which the module is assembled. The other model is less restrictive, eliminating the requirement for a substrate. The FEA modeling was performed using SolidWorks beginning with a thermal analysis followed by a stress analysis based on the temperature solution. Both the values and the trends of the temperatures and stresses were evaluated. The temperature results agreed to within 3.2°C. The trends and sign of the stresses were correctly predicted, but the magnitudes were not. One of the significant advantages of ParaPower is the speed of the computation. The run time for the parametric analysis was roughly two orders of magnitude faster than the FEA. This made it possible to build the model and complete the parametric analysis of roughly 500 runs in less than a day.

Simplified models for residual stress prediction in thermally sprayed coatings

2008 ◽  
Vol 222 (11) ◽  
pp. 2053-2068 ◽  
Author(s):  
A M Kamara ◽  
K Davey
Keyword(s):  
Residual Stress ◽  
Layer Thickness ◽  
Coating Thickness ◽  
Interfacial Stress ◽  
Analytical Models ◽  
Elastic Behaviour ◽  
Layer Deposition ◽  
Thermally Sprayed Coatings ◽  
Thermally Sprayed ◽  
Sprayed Coatings

Residual stress in thermally sprayed coatings is known to cause a range of problems, notably debonding, cracking, and spallation. The focus in this paper is on the development of simple analytical models for the prediction of residual stress that arise from spraying a steel-alloy coating onto a copper-alloy substrate. This is a material combination that has been used recently to enhance the thermal and mechanical efficiency of the pressure die casting process although problems with debonding have been reported in the literature. Three analytical models are developed and investigated, where each represent combinations of assumptions for coating and substrate material behaviours during coating manufacture. The sensitivity of these combinations on residual stress, developed for a range of process parameters (deposited layer thickness, interval of layer deposition and the number of layers in a coating, i.e. block deposition versus multi-layer deposition for a desired coating thickness) is recorded. In agreement with experimental and finite-element modelling results from a previous study, the results from all the three models assessed in the current study indicate a progressive change in average interfacial residual stress from compressive towards tensile with an increase in the thickness of the deposited layer; and a tensile interfacial stress in a two-layer coating, which increases with an increase in the interval of deposition between the two layers. The observations from the results suggest an increase in potential for coating debonding with an increase in both deposited layer thickness and layer deposition interval. The results further suggest higher potential for coating debonding with block deposition compared with multi-layer deposition for a desired coating thickness. In terms of stress magnitudes, the model that performs best is one where the assumption that a currently deposited coating layer yields during its quenching phase and adopts elastic behaviour afterwards; and the strain generated in the substrate during the quenching phase is from thermal effect only while in the other phases afterwards, is from both thermal and elastic effects.

An Oil Stiction Model for Flat Armature Solenoid Switching Valves

2013 ◽  
Author(s):  
Rudolf Scheidl ◽  
Christoph Gradl
Keyword(s):  
Vapor Pressure ◽  
Finite Volume Method ◽  
Finite Volume ◽  
Force Control ◽  
Reynolds Equation ◽  
Analytical Models ◽  
Volume Increase ◽  
Fast Switching ◽  
Force Reduction ◽  
Volume Method

Oil stiction forces significantly influence the performance of fast switching valves. These forces stem from the significant lowering of the pressures between two oil filled plates relative to the surrounding pressure when the plates are quickly separated. If the pressure in the gap stays above the vapor pressure the stiction force can be derived from a solution of the Reynolds equation. However, for very fast motions — as occur in fast switching valves with a flat armature solenoid — cavitation is most likely to occur. The cavitation zone starts in central parts of the gap and extends as long as the gap volume increase cannot be fully compensated by the flow in the gap. Cavitation reduces the stiction force significantly. In many valves this stiction force reduction is decisive for a proper functioning of the valve. An important measure for stiction force control are flushing channels, in particular flushing bores. In this paper analytical models and Finite Volume method models are used to study the stiction force problems with and without cavitation and design measures for their mastering.

Roughness development in electrodeposited ultrathin cobalt and nickel layers

2000 ◽  
Vol 15 (2) ◽  
pp. 458-462 ◽  
Author(s):  
Robert F. Renner ◽  
KNona C. Liddell
Keyword(s):  
Atomic Force Microscopy ◽  
Film Thickness ◽  
Layer Thickness ◽  
Root Mean Square ◽  
Basal Layer ◽  
Peak Height ◽  
Mean Square ◽  
Peak Density ◽  
Force Microscopy ◽  
Atomic Force

For both Co and Ni, a series of electrodeposited films of varying thickness (2–10 nm) was grown under otherwise identical conditions using potentiostatic control. The substrates were pieces of Si wafer onto which a Cu basal layer had been thermally evaporated. Contact mode atomic force microscopy was used to measure both the root-mean-square peak height (nm) and the areal peak density (μm−2) of each film. Root-mean-square (rms) peak heights for Co initially increase with film thickness and then plateau at a layer thickness of 3 nm. For Ni, the rms peak heights increase almost linearly for layer thicknesses less than 11 nm, reaching a value of 6 nm. Peak density shows the opposite trend, decreasing with layer thickness before reaching an approximately constant value for both metals at a film thickness of 4 nm. The atomic force microscopy data indicate that Ni and Co have different deposition mechanisms. A Co film initially nucleates rapidly; then the nucleation phase is followed by multinuclear, multilayer growth. Ni deposits also have initial rapid nucleation, but the dominant growth mode is primarily vertical, with increasing peak heights but no change in peak density. Increased peak density is linearly correlated with decreased peak height for the thinnest films in both systems.

Numerical Analysis of Mechanical Test Methods for Evaluating Shear Strength of Joint by Using Interface Element

2007 ◽  
Vol 345-346 ◽  
pp. 1489-1492 ◽  
Author(s):  
Hisashi Serizawa ◽  
Kazuaki Katayama ◽  
Charles Lewinsohn ◽  
Mrityunjay Singh ◽  
Hidekazu Murakawa
Keyword(s):  
Residual Stress ◽  
Shear Strength ◽  
Tensile Test ◽  
Layer Thickness ◽  
Mechanical Test ◽  
Test Methods ◽  
Bending Test ◽  
Interface Element ◽  
Initiation Point ◽  
Calculation Results

As examples of the most typical methods to determine the shear strength of SiC/SiC composite joints, the tensile test of lap joined composite and the asymmetrical four point bending test of butt joined composite were analyzed by using finite element method with the interface element. From the calculation results, it was revealed that the strength in the tensile test was strongly influenced by the residual stress as the increase of the joint layer thickness. In the case of asymmetrical bending test, it was found that the crack initiation point would move due to the residual stress and the strength was also affected by the joint layer thickness.

scholarly journals Propeller Load Modelling In The Calculations Of Marine Shafting Torsional Vibrations

2021 ◽  
Vol 93 (6s) ◽  
pp. 204-216
Author(s):  
Nenad Vulić ◽  
◽  
Karlo Bratić ◽  
Branko Lalić ◽  
Ladislav Stazić ◽  
...  
Keyword(s):  
Steady State ◽  
Dynamic System ◽  
Simulation Modelling ◽  
Analytical Models ◽  
Torsional Vibrations ◽  
Class Society ◽  
Marine Propulsion ◽  
Maritime Studies ◽  
Calculation Results ◽  
Service Loading

Technical rules of IACS classification societies require that calculations of torsional vibrations for all propulsion shafting systems, as well as for shafting systems of auxiliary machinery above certain power, shall be prepared, submitted and validated for the vessels requesting the class certificate. These calculations may be approached either by conventional analytical models based upon systems of ordinary differential equations describing the actual dynamic system, or by simulation modelling of the same dynamic system. The research team of the authors has been established within the R&D Centre of the Faculty of Maritime Studies at Split. The aim of the team is to investigate possibilities and constraints for implementation of the SimulationX software to the simulation modelling of torsional vibrations of dynamic systems, such as marine propulsion and auxiliary shafting. In general, results of these calculations depend upon the concept of the system (two-stroke vs. four-stroke Diesel engine, torsional vibration damper present or not, flexible coupling present or not, fixed pitch or controllable pitch propeller, etc.), dimensions of components, their material properties and service loading. Propeller load modelling within the service loading is very important. Even the preliminary research results show that its simplest part, i.e. the steady-state propeller loading of the system without taking excitations into account, may have a significant influence on the results of torsional vibrations calculation and consequently even to their acceptability by the class society. For this reason, the present paper describes two different ways to express propeller steady-state loading formulations, as prescribed by different sources and authorities, as well as their influence on the torsional vibrations calculation results and meeting the criteria of the IACS Unified Requirements, presenting them in a real verified and validated case study.

scholarly journals Calculation possibilities and Eurokod 3 requirements used to calculate internal forces in shell structures

2014 ◽  
Vol 13 (2) ◽  
pp. 143-151
Author(s):  
Wiesław Baran
Keyword(s):  
Analytical Solutions ◽  
Numerical Models ◽  
Shell Structures ◽  
Analytical Models ◽  
Calculation Results ◽  
Internal Forces ◽  
Calculation Analysis

This work presents various types of calculation analysis for shell designing, recommended by Eurokod 3. Analytical solutions for shell groups enabling calculating internal forces for any load are presented. The influence of nonlinear units in geometrical connections on calculation results was analyzed . Necessity of proper researcher preparation to build numerical models of shells and necessity to verify them by analytical models was underlined.

Thermal cycling effect on a structure of multilayer composite material made of 08kp and 08Kh18N10 steels

2021 ◽  
Author(s):  
A.A. Khudnev ◽  
A.I. Plokhikh ◽  
A.N. Bolshakova ◽  
R.M. Dvoretskov
Keyword(s):  
Heat Treatment ◽  
Composite Material ◽  
Thermal Cycling ◽  
Layer Thickness ◽  
Diffusion Path ◽  
Layered Composite ◽  
Layered Material ◽  
Material Structure ◽  
Multilayer Composite ◽  
Chromium Diffusion

The article researches the effect of five cycles of heating to a temperature of 1000 °C and two cycles of heating to a temperature of 1100 °C on the structure of a layered composite material consisted of 100 alternating layers of 08kp and 08Kh18N10 steels (one layer thickness is ~22 μm). As a result of the nickel and chromium diffusion during thermocycling, the thickness of the layers changed and an interlayer with a structure different from the structure of neighboring layers was formed. Heating to 1100 °C also has led to a partial disarrangement of the layered material structure. It was found that the real diffusion path of alloying elements during heat treatment significantly exceeds the calculated one, and chromium atoms are redistributed between the layers of the material much more actively than nickel atoms.

Effect of high-frequency PCB laminate on thermal cycling behavior of electronic packaging structures

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Lijuan Huang ◽  
Zhenghu Zhu ◽  
Hiarui Wu ◽  
Xu Long
Keyword(s):  
Fatigue Life ◽  
Thermal Cycling ◽  
Electronic Packaging ◽  
High Frequency ◽  
Solder Joints ◽  
Fatigue Cracks ◽  
Cyclic Stress ◽  
Content Type ◽  
Stress States ◽  
Packaging Structure

PurposeAs the solution to improve fatigue life and mechanical reliability of packaging structure, the material selection in PCB stack-up and partitioning design on PCB to eliminate the electromagnetic interference by keeping all circuit functions separate are suggested to be optimized from the mechanical stress point of view.Design/methodology/approachThe present paper investigated the effect of RO4350B and RT5880 printed circuit board (PCB) laminates on fatigue life of the QFN (quad flat no-lead) packaging structure for high-frequency applications. During accelerated thermal cycling between −50 °C and 100 °C, the mismatched coefficients of thermal expansion (CTE) between packaging and PCB materials, initial PCB warping deformation and locally concentrated stress states significantly affected the fatigue life of the packaging structure. The intermetallics layer and mechanical strength of solder joints were examined to ensure the satisfactorily soldering quality prior to the thermal cycling process. The failure mechanism was investigated by the metallographic observations using a scanning electron microscope.FindingsTypical fatigue behavior was revealed by grain coarsening due to cyclic stress, while at critical locations of packaging structures, the crack propagations were confirmed to be accompanied with coarsened grains by dye penetration tests. It is confirmed that the cyclic stress induced fatigue deformation is dominant in the deformation history of both PCB laminates. Due to the greater CTE differences in the RT5880 PCB laminate with those of the packaging materials, the thermally induced strains among different layered materials were more mismatched and led to the initiation and propagation of fatigue cracks in solder joints subjected to more severe stress states.Originality/valueIn addition to the electrical insulation and thermal dissipation, electronic packaging structures play a key role in mechanical connections between IC chips and PCB.

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