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Electronics Packaging Papers (98 entries)
 
3-Dimensional Thermal Analysis and Active Cooling of Short-Length High-Power Fiber Lasers
  L. Li, H. Li, T. Qiu, V. L. Temyanko, M. M. Morrell, and A. Schülzgen
  "A fully 3-dimensional finite element model has been developed that simulates the internal temperature distribution of short-length highpower fiber lasers. We have validated the numerical model by building a short, cladding-pumped, Er-Yb-codoped fiber laser and measuring the core temperature during laser operation. A dual-end-pumped, actively cooled, fiber laser has generated >11 W CW output power at 1535 nm from only 11.9 cm of active fiber. Simulations indicate power-scaling possibilities with improved fiber and cooling designs."
[ANSYS Thermal, version 6.1]
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Average Rating: 9.0 (10 votes)  
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A 64-Pixel Linear Thermopile Array Chip Designed for Vacuum Environment
  U. Dillner, E. Kessler, V. Baier, A. Berger, T. Eick, D. Behrendt, H. Urban
  "We report on the development of a 64-pixel high performance linear thermopile array chip designed for vacuum environment based on a silicon nitride membrane as substrate, Bi0.87Sb0.13/Sb as thermoelectric materials combination and an Ag-black broadband absorber layer. The array chip was mounted on a ceramic substrate and placed on the socket of a commercial hybrid package with 64 pins. Measurements of the linear array chip in vacuum environment and in absence of an entrance filter delivered a responsivity of 245 V/W, a sensitivity of 166 µVm²/W, a specific detectivity of 1.6x109 cmHz1/2/W at an electrical resistance of 9 k and a thermal time constant of 150 ms. The pixelto- pixel cross-talk was reduced to less than 0.4 % due to slits in the membrane between adjacent pixels made by dry etching."
[ANSYS Thermal, version unknown]
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Average Rating: 10.0 (3 votes)  
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A Compilation of Anand Parameters for Selected SnPb and Pb-free Solder Alloys
  Zane Johnson (University of Minnesota)
  "Finite-element (FE) simulation is widely used in electronic packaging. It is particularly useful in the design of solder joint attachments. To ensure fidelity, FE simulation must capture the highly nonlinear behavior of solder. One useful material model for solder is Anand’s viscoplastic model. A compilation of Anand parameters reported in the literature for a variety of solder alloys is provided."
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Average Rating: 10.0 (6 votes)  
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A High-Performance Tunneling Accelerometer
  Edward Boyden, Osamah El Rifai, Brian Hubert, Maurice Karpman, Dave Roberts
  Design of a MEMS tunneling accelerometer. Uses ANSYS for part of the design verification. In Acrobat, search for occurences of "ANSYS" in the PDF file.
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Average Rating: 9.0 (48 votes)  
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A Microchip-Based PCR Device Using Flexible Printed Circuit Technology
  Keyue Shen, Xiaofang Chen, Min Guo, Jing Cheng,
  "Rapid heat transfer is crucial for an efficient polymerase chain reaction (PCR), and this makes temperature control one of the most essential features in a micro-PCR system, which always includes a heater and a sensor composing a closed-loop. Yet, the fabrication of the heater and the sensor often prevented micro-PCR systems from achieving both cost-effectiveness and fabrication-easiness. For most of the early researches micromachining techniques were used to allow sensors and heaters be integrated on a silicon or glass chip. However, the cost prevented them from wide applications. The work described in this paper is part of our effort to solve the cost/fabrication dilemma. An innovative digital temperature control system was developed by introducing a heater/sensor switching procedure. Only one temperature controlling element fabricated by flexible printed circuit technology was utilized in the constructed PCR device with minimum fabrication steps. The glass chip-based device was made from low cost materials and assembled with adhesive bonding. Through seemingly simple steps, we obtained both disposability and portability at the same time. Temperature stability within ±0.3 ?C and a transitional rate of 8 ?C/s during heating/cooling was achieved. A 244 bp DNA fragment of hepatitis C virus was successfully amplified in our device by a three-stage thermal cycling process. Further improvement was assisted by finite element analysis, and demonstrated by experiment."
[ANSYS Thermal, version 7.0]
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Average Rating: 10.0 (6 votes)  
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A New High Resolution Thermal Detector Array
  U. Dillner, R. Riesenberg
  "The performance of the new thermal detector array arrangement is calculated using thermal finite element analysis. The influence of the thermal intra- and inter-subarray cross-talk on the resolution in dependence on some geometrical dimensions of the array is presented."
[ANSYS Thermal, version 5.7]
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Average Rating: 10.0 (3 votes)  
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A New Type of High Bandwidth RF MEMS Switch - Toggle Switch
  Bernd Schauwecker, Karl M. Strohm, Winfried Simon, Jan Mehner, and Johann-Friedrich Luy
  "A new type of RF MEMS switch for low voltage actuation, high broadband application and high power capability is presented. Mechanical and electromagnetic simulations of this new RF MEMS switch type are shown and the fabrication process and measurement results are given. The switching element consists of a cantilever which is fixed by a suspension spring to the ground of the coplanar line. The closing voltage is 16V. The switches exhibit low insertion loss (<0.85dB@30GHz) with good isolation (>22dB@30GHz). I."
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Average Rating: 10.0 (1 vote)  
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A Novel Micromachined 2x128-Element Linear Themoelectric Infrared Radiation Sensor Array
  Jurgen Muller, Volker Baier, Ulrich Dillner, Rudolf Guttich, Ernst Kessler
  "As a component for infrared spectrometric analytical instruments a 2x128-element thin-film thermopile linear array sensor with a staggered pixel arrangement was constructed. Contrary to most of the known 1-dimensional and 2-dimensional thermoelectric infrared sensor arrays working all on the base of doped polysilicon, we use the material group Bi-Sb-Te to obtain highest values of thermoelectric efficiency and specific detectivity to realize an optimum of spectral wavelength resolution."
[ANSYS Thermal, version unknown]
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A Parametric Study of Flip Chip Reliability Based on Solder Fatigue Modelling
  Scott Popelar
  "The solder fatigue model has been utilized to investigate the reliability of flip chip joints subjected to thermal cycling. In particular, a parametric study had been performed which shows how various flip chip design parameters will affect solder joint fatigue. Finite element models have been developed to analyze the effect of die size, die thickness, solder joint height, cap diameter and underfill properties on solder fatigue." (This is Part I of the study. Part II of this paper is available here.)
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Average Rating: 9.4 (27 votes)  
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A Software Package Linking PE2D and ANSYS for SSC Magnet Design
  Nick Kallas, Chris Haddock, Jay Jayakumar, David Orrell, Greg Snitchler, Giancarlo Spigo, Jon Turner
  "The design of the Cold Mass(CM) of superconducting magnets at the Magnet Systems Division(MSD) of the Superconducting Super Collider Laboratory(SSCL) involves among others the optimization of field quality and structural performance as related to the quench behavior of the magnets. It is desirable to be able to study the changes in field quality due to dimensional changes of the cold mass components under stress as the magnet is cooled and energized. This document describes a software package of functions which enable the computer aided study of this aspect of cold mass design."
[ANSYS Structural, version 4.4a]
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Average Rating: 5.0 (4 votes)  
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A Stress-Induced Thermal Actuator for Optical Purpose
  Gang Liu, Sebaek Oh
  "We present a micromachined, stress-induced, thermal bimorph actuator for optical purpose. Piston motions of more than 3um are demonstrated by FEM simulation. Upon the release from the substrate, the actuators lift off the substrate due to a large built-in bending moment arising from the compressive residual stress in the poly-silicon layer and tensile residual stress in the metal layer. Large displacement and low operating voltage (<2V) are obtained simultaneously."
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Average Rating: 8.8 (17 votes)  
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A System Level Cooling Solution for Cellular Phone Applications
  Hassan Hashemi, Abdolreza Langari
  Paper on using ANSYS for thermal analysis of MCMs.
"To characterize package thermal performance at a component level, the authors used ANSYS 5.5. A sub modeling analysis technique was employed for this analysis."
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Average Rating: 9.5 (10 votes)  
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Accumulated Creep Strain and Energy Density Based Thermal Fatigue Life Prediction Models for SnAgCu Solder Joints
  Ahmer Syed
  "This paper describes in detail the life prediction models for SnAgCu solder joints. The models are based on published constitutive equations for this alloy and thermal cycle fatigue data on actual components. The approach uses advance finite element modeling and analysis techniques and is based on mechanics of deformation. Both accumulated creep strain and creep strain energy density based models are developed. The model has been correlated with a number of data points and predicts life within 25% in most cases. The framework of modeling and prediction methodology described here is fully compatible with the framework used for SnPb solder previously."
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Average Rating: 10.0 (12 votes)  
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Advanced Mask Modeling Accuracy and Stability Study-University of Wisconsin Mask Modeling
  R. Scott Mackay
  "As lithography error budgets on pattern placement become more stringent for sub-130 nm technology, it is imperative that all mask-related distortions be quantified, controlled, and minimized. It will be essential to identify the influence of thin film stress on pattern placement errors. In this research, the effect of mask material properties, manufacturing, and usage on image placement will be evaluated. Finite element (FE) models have been developed to simulate this pattern transfer process, using equivalent modeling techniques. Analytical, experimental, and FE procedures have been combined to accurately determine these effects on final pattern distortions."
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Average Rating: 10.0 (3 votes)  
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An Investigation into Vibration in Switched Reluctance Motors
  Pragasen Pillay and William (Wei) Cai
  "Two disadvantages of the switched reluctance motor (SRM) are its torque ripple and acoustic noise. Previous work on vibration modes and resonant frequencies of the laminations of an 8-6 SRM is extended here to include the effects of the frame. Both a smooth frame and a ribbed frame are examined, and the presence of numerous additional vibratory modes in the ribbed frame demonstrated. Accelerometer tests behind a pole verify some of the theoretical predictions."
[ANSYS Dynamics, version unspecified]
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Average Rating: 10.0 (1 vote)  
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Analysis and Simulation of the Ultrasonic/Sonic Driller/Corer(USDC)
  X. Bao, Z. Chang, S. Sherrit, B.P. Dolgin, Y. Bar-Cohen, D.S. Pal, S. Du, T. Peterson
  "An ultrasonic/sonic driller/corer (USDC) was developed to address the challenges to the NASA objective of planetary in-situ rock sampling and analysis. The USDC uses a novel drive mechanism, transferring ultrasonic vibration into impacts on a drill stem at sonic frequency using a free-flying mass block (free-mass). The main parts of the device and the interactions between them were analyzed and numerically modeled to understand the drive mechanism and allow design of effective drilling mechanism. A computer program was developed to simulate the operation of the USDC and successfully predicted the characteristic behavior of the new device. This paper covers the theory, the analytical models and the algorithms that were developed and the predicted results."
[ANSYS Piezoelectric, version 5.4]
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Average Rating: 10.0 (4 votes)  
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Analytical Simulation of a 1D Single Crystal Silicon Electrostatic Micromirror [PDF]
  H. Camon, F. Larnaudie, F. Rivoirard, B. Jammes
  A torsional micromirror. Use of ANSYS to extract lumped parameters for use in SABER model. (MEMS)
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Average Rating: 8.6 (11 votes)  
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Analyzing Microminiature Devices [PDF]
  Steve Groothuis
  (from ANSYS Solutions magazine, volume 1, #1) (MEMS)
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Average Rating: 10.0 (7 votes)  
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ANSYS Multiphysics Capabilities for MEMS Modeling and Simulation - Part 1 of 3
  Jan Mehner, Juergen Wibbeler
  Part 1 of 3: Analyzing electrostatic-structural interactions in Micro Electro Mechanical Systems
ANSYS Solutions Vol. 3, Number 2
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Average Rating: 10.0 (5 votes)  
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ANSYS Multiphysics Capabilities for MEMS Modeling and Simulation - Part 2 of 3
  Jan Mehner, Juergen Wibbeler
  Part 2 of 3: Analyzing fluid-structural interactions
ANSYS Solutions Vol. 3, Number 3
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Average Rating: 10.0 (4 votes)  
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ANSYS Multiphysics Capabilities for MEMS Modeling and Simulation - Part 3 of 3
  Jan Mehner, Juergen Wibbeler, Fouad Bennini
  Part 3 of 3: Exporting macromodels for circuit and system simulation tools.
ANSYS Solutions Vol. 3, Number 4
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Average Rating: 10.0 (3 votes)  
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ANSYS-Structural Design of Micromachined Fabry-Pérot Filters for WDM Applications
  K. Mutamba, J. Pfeiffer, J. Peerlings, R. Riemenschneider and N. Dragojevic
  "Due to the recent progress in the fabrication of micro-optical devices and the maturity reached in the integration of electromechanical functions on various semiconductor micro-devices, new concepts for optical microelectromechanical systems (OMEMS) have emerged... Analyses have been carried out with the ANSYS FEM (Finite Elements Method) Program for two types of electrostatically actuated Fabry-Pérot filters."
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Average Rating: 10.0 (4 votes)  
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APDL Implementation of a 3D FEM Capacitance Simulator for Arbitrarily Shaped Interconnects [PDF]
  Andreas Hieke
  Alternative download link here
An alternate CMATRIX macro created by A. Hieke called CAMACO.

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Average Rating: 7.5 (4 votes)  
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Applying Anand Model to Represent the Viscoplastic Deformation Behavior of Solder Alloys
  G. Z. Wang, Z. N. Cheng, K. Becker, J. Wilde
  "A unified viscoplastic constitutive law, the Anand model, was applied to represent the inelastic deformation behavior for solders used in electronic packaging. The material parameters of the constitutive relations for 62Sn36Pb2Ag, 60Sn40Pb, 96.5Sn3.5Ag, and 97.5Pb2.5Sn solders were determined from separated constitutive relations and experimental results. The achieved unified Anand model for solders were tested for constant strain rate testing, steady-state plastic flow and stress/strain responses under cyclic loading. It is concluded that the Anand model can be applied for representing the inelastic deformation behavior of solders at high homologous temperature and can be recommended for finite element simulation of the stress/strain responses of solder joints in service."
[ANSYS Nonlinear, version unknown]
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Average Rating: 10.0 (3 votes)  
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ATLAS TRT Barrel Electronics Cooling: Duke mockup measurements and FEA calculations
  W. Ebenstein, J. Fowler, S. Oh, V. Vassilakopoulos, and C. Wang
  "This report summarizes measurements and calculations using the most recently proposed cooling scheme. Heat generated by the ASDBLR and DTMROC stamp boards is conducted to an aluminum plate sandwiched between the upper and lower stamp boards (hereafter referred to as the 'middle cooling plate'). The heat is then carried up through a vertical aluminum post, and finally to a large aluminum plate above all of the upper stamp boards (the 'upper cooling plate'), to which cooling tubes are attached."
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Average Rating: 10.0 (1 vote)  
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Calculations on Micromachined Electro-Thermal Sensor Devices
  Bernd Folkmer, Martin Hirt, Michael Vosseler, Hartmut Glosch, Frank Hedrich, Sophie Billat, Walter L
  "In this contribution the experiences gained using ANSYS/Multiphysics software for analysis of micro machined electro-thermal sensor devices are described."
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Average Rating: 10.0 (5 votes)  
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Characterization and Analysis on the Solder Ball Shear Testing Conditions
  Xingjia Huang, S.W. Ricky Lee, Chien Chun Yan, and Sam Hui
  "This paper presents both experimental investigation and computational analysis on the solder ball shear testing conditions for ball grid array (BGA) packages." (Creep, contact)
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Average Rating: 4.4 (9 votes)  
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Comprehensive Solder Fatigue And Thermal Characterization Of A Silicon Based Multi-Chip Module Package Utilizing Finite Element Analysis Methodologies
  Bret A. Zahn
  "Viscoplastic finite-element simulation methodologies were utilized to predict ball and bump solder joint reliability for a silicon based five-chip multi-chip module package under accelerated temperature cycling conditions." (Nonlinear, Anand)
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Average Rating: 10.0 (9 votes)  
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Constitutive Relationship Development, Modeling and Measurement of Heat Stressing of Micro-SMD Assembly with Sn3.9Ag0.6Cu SAC Alloy
  Qiang Xiao, William Armstrong, James Pitarresi, Satish Chaparala, Brian Rogeman, Bahgat Sammakia, Lu
  "The thermal-mechanical response of electronic packages was simulated using the commercial finite element code ANSYS coupled with the Garofalo model to represent the solder constitutive creep response. The measured properties for bulk and thin-cast Sn3.9Ag0.6Cu SAC alloy were used in the FE modeling."
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Average Rating: 0.0 (2 votes)  
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Cooling the APS Storage Ring Radio-Frequency Accelerating Cavities: Thermal/Stress/Fatigue Analysis and Cavity Cooling Configuration
  K. Primdahl, R. Kustom
  "Heat transfer studies, including finite-element analysis and test results, of the Advanced Photon Source (APS) storage ring 352-MHz radio-frequency (rf) accelerating cavities are described. Stress and fatigue life of the copper are discussed. Configuration of water cooling is presented."
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Delamination in Patterned Films
  X.H. Liu, M.W. Lane, T.M. Shaw, E. Simonyi
  "When the dielectric constant of an insulator in an interconnect is reduced, mechanical properties are often compromised, giving rise to significant challenges in interconnect integration and reliability. Due to low adhesion of the dielectric an interfacial crack may occur during fabrication and testing. To understand the effect of interconnect structure, an interfacial fracture mechanics model has been analyzed for patterned films undergoing a typical thermal excursion during the integration process. It is found that the underlayer pattern generates a driving force for delamination and changes the mode mixity of the delamination. The implications of our findings to interconnect processes and reliability testing have been discussed."
[ANSYS Structural, version unknown]
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Design and Analysis of Ultrasonic Actuator in Consideration of Length-Reduction for a USDC (Ultrasonic/Sonic Driller/Corer)
  Z. Chang, S. Sherrit, M. Badescu, X. Bao, and Y. Bar-Cohen
  "The USDC uses a novel driving mechanism, transferring ultrasonic vibration to sonic frequency impacts with the aid of a free-flying mass block (free-mass). The free mass then drives the drill bit. The actuator consists of a stack of piezoelectric disks with a horn that amplifies the induced vibration amplitudes. The standard USDC is a slender device, and some times its length is too long for specific NASA missions. It is of current interest to have novel designs that reduce the length of the device. For this purpose, two novel horn designs were examined analytically. One is the flipped horn, the other is the planar folded horn. The new designs of the horn were analyzed using finite element modeling and the results allow for the determination of the control parameters that can optimize the performance of the ultrasonic horn in terms of the tip displacement and velocity. The results of the modeling are described and discussed in this paper."
[ANSYS Piezoelectric, version 5.4]
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Average Rating: 10.0 (5 votes)  
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Design and Characterization of Thin Film Microcoolers
  Chris LaBounty, Ali Shakouri, John E. Bowers
  "Thin film coolers can provide large cooling power densities compared to bulk thermoelectrics due to the close spacing of hot and cold junctions. Important parameters in the design of such coolers are investigated theoretically and experimentally. A three-dimensional finite element simulator (ANSYS) is used to model self-consistently thermal and electrical properties of a complete device structure."
[ANSYS Thermal, version 5.5.3]
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Design and Implementation of a Flow Microsensor by using Silicon Microelectronics Technology
  Roberto Rodrigues and Rogerio Furlan
  "This work presents the design of a gas flow microsensor that was implemented by using silicon microelectronics technology. Its main features are a low power consumption (tens of mW) and the possibility of integration in flow microactuators. It was adopted a calorimetric device with free-standing microfilaments and thermoresistive sensor elements. Analytical and numerical modeling were developed for device analyses and design. The free-standing microfilaments were fabricated using surface micromachining. Characteristic curves, of output voltage vs. flow, were obtained by using a commercial flow sensor for calibration. A good agreement was obtained comparing the flow microsensor experimental characteristic curves with numerical simulation results."
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Average Rating: 10.0 (7 votes)  
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Design And Manufacturing Of Micro Via-In-Pad Substrates For Solder Bumped Flip Chip Applications
  John Lau, Chris Chang, Ricky Lee, Tsung-Yuan Chen, David Cheng, Tzyy Jang Tseng, Dyna Lin
  "A novel and low-cost micro via-in-pad (VIP) substrate for supporting a solder bumped flip chip is presented in this study. Non-linear finite element analyses are used to determine the stress and strain in the copper VIP and the solder joint. Time-dependent non-linear analysis is used to predict the thermal-fatigue life of the VIP solder joint." (Nonlinear, Anand)
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Average Rating: 5.0 (1 vote)  
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Design, Fabrication, and Testing of Fixed-Valve Micro-Pumps [PDF]
  F. Forster, R. Bardell, M. Afromowitz, N. Sharma, and A. Blanchard
  Use of Flotran for micropump analysis. (MEMS)
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Average Rating: 6.7 (3 votes)  
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Development of CAD Model for MEMS Micropumps [PDF]
  M. Arik, S. M. Zurn, A. Bar-Cohen, Y. Nam, D. Markus, and D. Polla
  Use of ANSYS in modal and harmonic analysis of micropumps (PZT cantilever beams). (MEMS)
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Average Rating: 4.2 (6 votes)  
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Development of Convective Reflow-Projection Moiré Warpage Measurement System and Prediction of Solder Bump Reliability on Board Assemblies Affected by
  Wei Tan (Georgia Institute of Technology)
  "The effect of PWB warpage on the low cycle fatigue of the solder bumps on board assemblies was investigated using FEM and experimental study. The three- dimensional (3-D) models of PWBAs with varying board warpage were used to estimate the solder bump fatigue life for different types of plastic ball grid array (PBGA) packages mounted on PWBs. In order to improve the accuracy of FE results, the projection moiré technique was used to measure the initial warpage of PWBs, and this warpage was used as a geometric input to the FEM. Both Sn-Pb and lead-free solder materials were used in this study. The simulation results were validated and correlated with the experimental results obtained using the projection moiré system and accelerated thermal cycling tests. Design of experiments and an advanced prediction model were generated to predict board level solder bump fatigue life based on the initial PWB warpage, package dimensions and locations, and solder bump materials."
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Dynamic Shock Simulation Of A Computer Hard Drive Using an ANSYS/LS-DYNA Implicit-Explicit Sequential Solution
  Chris Andersen, John Stricklin
  "This paper describes a nonlinear transient dynamic analysis of a computer hard drive using ANSYS in combination with ANSYS/LS-DYNA. The model includes the enclosure, platters, spindle, read/write heads, and other key components. The objective of the analysis was to determine the interaction between the parts in this assembly, such as lift off and impact between the read/write heads and platters, when the hard drive is subjected to a 250 G half sinusoid shock load. This load simulates a shock test, which the manufacturer does to qualify hard drives." From 2000 Conference
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Average Rating: 9.2 (40 votes)  
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Effect of Package Design and Layout on BGA Solder Joint Reliability of an Organic C4 Package
  Biju Chandran, Deepak Goyal, and Jeffrey Thomas
  "Ball Grid Array (BGA) is currently the interconnect of choice for attaching microprocessors on a printed circuit board (PCB). The reliability of solder joints is one of the critical issues in BGA surface mount technology (SMT). During reliability testing, BGA fatigue failures were observed on test vehicles (TV). Finite element analysis and physical failure analysis were used to determine the risk to the product in the field. As part of this effort, parametric finite element analysis was carried out to determine the effect of design features like the package size, and BGA pattern on the propensity of fatigue failure. The results of the finite element analysis and physical failure analysis showed that the risk to fatigue failure was much greater on a peripheral / partial grid array package than in a full grid array package."
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Average Rating: 10.0 (3 votes)  
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Effect of Simulation Methodology on Solder Joint Crack Growth Correlation
  Robert Darveaux
  "A generalized solder joint fatigue life model for surface mount packages was previously published in Refs [1,2]. The model is based on correlation to measured crack growth data on BGA joints during thermal cycling. It was subsequently discovered by Anderson et.al. that the ANSYS TM 5.2 finite element code used in the model had an error in its method for calculating plastic work [3]. It was shown that significant error in life prediction could result by using a recent version of the code where the bug has been fixed. The error comes about since the original crack growth constants were derived based on plastic work calculations that had the bug.
In this paper, crack initiation and growth constants are re-calculated using ANSYS 5.6. In addition, several other model related issues are explored with respect to the crack growth correlations. For example, 3D slice models were compared to quarter symmetry models. Anand’s constitutive model was compared with Darveaux’s constitutive model. It was shown that the crack growth rate dependence on strain energy density always had an exponent of 1.10 +/- 0.15. This is in the range of the original correlation, so the accuracy of relative predictions should still be within +/- 25%. However, the accuracy of absolute predictions could be off by a factor of 7 in the worst case, if the analyst uses a modeling procedure that is not consistent with that used for the crack growth correlation. The key to good accuracy is to maintain consistency in the modeling procedure."

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Average Rating: 10.0 (6 votes)  
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Electromechanical analysis of micromechanical SOI-fabricated RF resonators
  T. Lamminmaki, K. Ruokonen, I. Tittonen, T. Mattila, O. Jaakkola, A. Oja, H. Seppa, P. Seppala, and
  "In this paper, finite element method (FEM) simulations are used to model mechanical properties of MEMS resonators. Using a static displacement analysis the effective spring constant and mass are calculated. Nonlinearity of the mechanical restoring force is simulated to analyze large amplitude behavior of the resonator."
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Average Rating: 10.0 (5 votes)  
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Electromechanical Transducer Element for MEMS Analysis in ANSYS [PDF]
  Miklos Gyimesi, Dale Ostergaard
  Presented at MSM 1999. (MEMS)
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Average Rating: 10.0 (2 votes)  
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Finite Element Analysis for Solder Ball Connect (SBC) Structural Design Optimization
  J.S. Corbin
  "Solder Ball Connect (SBC) is a second-level surface mount electronics packaging technology in which ceramic modules containing one or more chips are joined to a circuit card (FR-4) by means of an array of nonhomogeneous solder columns. These columns consist of a high-temperature-melting 90%Pb/lO%Sn solder sphere attached to the module and card with eutectic solder fillets. The solder structures accommodate the bulk of the strain (which is due to the thermal- expansion mismatch between FR-4 and the 9211 ceramic of the modules) generated during power cycling. If the solder structures are not properly designed, the thermal strain can be a source of premature fatigue failure. In this work, finite element analysis is used to characterize the plastic strains that develop in the SBC interconnection during thermal cycling. Since plastic strain is a dominant parameter that influences low-cycle fatigue, it is used as a basis of comparison for various structural alternatives. Designed experiment techniques are used to systematically evaluate the thermal strain sensitivity to structural variables. Results are used to identify an optimally reliable structure that is robust in terms of assembly-process variables."
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Average Rating: 10.0 (4 votes)  
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Finite Element Based Reduced Order Modeling of MEMS [PDF]
  Dale Ostergaard, Miklos Gyimesi
  Presented at MSM 2000. (MEMS)
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Average Rating: 10.0 (1 vote)  
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Finite Element Based Solder Joint Fatigue Life Predictions for a Same Die Stacked Chip Scale Ball Grid Array Package
  Bret Zahn
  "Viscoplastic finite-element simulation methodologies were utilized to predict solder joint reliability for a same die size, stacked, chip scale, ball grid array package under accelerated temperature cycling conditions (-40C to +125C, 15min ramps/15min dwells). The effects of multiple die attach material configurations were investigated along with the thickness of the mold cap and spacer die. The solder structures accommodate the bulk of the plastic strain that is generated during accelerated temperature cycling due to the thermal expansion mismatch between the various materials that encompass the stacked die package. Since plastic strain is a dominant parameter that influences low-cycle fatigue, it was used as a basis for evaluation of solder joint structural integrity. The paper discusses the analysis methodologies as implemented in the ANSYS finite element simulation software tool and the corresponding results for the solder joint fatigue life. Some ANSYS parametric design language commands are included for the benefit of those readers who are familiar with the tool."
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Average Rating: 9.7 (15 votes)  
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Finite Element Modeling of Capacitor Micromachined Ultrasonic Transducers
  Yongrae Roh and Butrus T. Khuri-Yakub
  "A finite element model of cMUTs is constructed using the commercial code ANSYS. The complex load impedance seen by individual cells is compared with the plane wave real impedance seen by a parallel combination of the cells to make a transducer. The result shows the origin and level of crosstalk between array elements, with evidence of coupling through Stoneley and Lamb waves." (acoustics)
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Average Rating: 8.8 (8 votes)  
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Finite Elements for Thermoelectric Device Analysis in ANSYS
  Elena Antonova and David Looman
  "A new set of ANSYS coupled-field elements enables users to accurately and efficiently analyze thermoelectric devices. This paper reviews the finite element formulation, which, in addition to Joule heating, includes Seebeck, Peltier, and Thomson effects. Examples of steady-state and transient simulations of a thermoelectric generator and a single-stage Peltier cooler are presented for thermoelectric analysis verification. An analysis of a multistage thermoelectric cooler is performed to demonstrate ANSYS parametric analysis capability."
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Average Rating: 9.2 (6 votes)  
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First Micromachined Silicon Load Cell for Loads up to 1000 kg
  Henk Wensink, Meint J. de Boer, Remco J. Wiegerink, Robert A.F. Zwijze, Miko C. Elwenspoek
  "In this paper, a bulk micromachined silicon load cell is presented, designed for loads up to 1000 kg. ANSYS simulations were used to determine the load cell dimensions and strain gauge positions."
See related paper.
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Flip Chip Reliability Modeling Based on Solder Fatigue as Applied to Flip Chip on Laminate Assemblies
  Scott Popelar, Michael Roesch
  "A 63Sn/Pb solder fatigue model has been previously developed based on a correlation of flip chip solder fatigue data combined with nonlinear finite element analysis. This model has been successfully applied in the prediction of PBGA and CSP fatigue lives as well as a parametric study investigating the reliability of flip chip assemblies and the influence of specific design parameters. In this investigation, flip chip reliability predictions are generated based on solder fatigue modeling and compared to actual thermal cycling reliability data. The influence of both solder fatigue and underfill delamination are considered in interpretation of the experimental data."
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Floating Metal Plane on Thermal and Electrical Performance of an Enhanced Plastic Ball Grid Array Package
  Humayun Kabir, Richard Groover, David Tovar and Joe Joroski
  "Three-dimensional finite element models of a cavity down thin and thermally enhanced BGA (T2BGA) package have been developed using ANSYS. This model has been used for thermal characterization of the above package under different cooling (airflow) conditions and to investigate the effects of heat spreader thickness on package junction to ambient thermal resistances for no airflow condition."
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FLOTRAN Chills Out Hot Aerospace Electronics
  Mark Troscinski, Jiang Guangnan, Zhang Minyi
  Examples of use of Flotran for electronics applications.
From ANSYS Solutions, Vol. 4 Number 2.
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Average Rating: 9.4 (8 votes)  
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HDPUG's Design for Lead-Free Solder Joint Reliability of High-Density Packages
  J. Lau, W. Dauksher, J. Smetana, R. Horsley, D. Shangguan, T. Castello, I. Menis, D. Love, B. Sulliv
  "The lead-free solder-joint reliability of the high-density packages, 256-pin PBGA (plastic ball grid array), 388-pin PBGA, and 1657-pin CCGA (ceramic column grid array), on PCB (printed circuit board) subjected to temperature cycling is investigated. Emphasis is placed on the determination of the creep responses (e.g., stress, strain, and strain energy density) of the lead-free solder joints of these packages. The lead-free solder is assumed to obey the Garofalo-Arrhenius creep constitutive law. The results presented herein should be useful for a better understanding of the thermal-mechanical behaviors of the lead-free solder joints in these high-density package assemblies."
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Hybrid Finite Element - Trefftz Method for Open Boundary Analysis [PDF]
  Miklos Gyimesi, Igor Tsukerman and Doug Lavers
  Presented at MSM 2000. (MEMS)
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Average Rating: 10.0 (2 votes)  
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Hybrid P-Element and Trefftz Method for Capacitance Computation [PDF]
  Miklos Gyimesi, Jian-She Wang, Dale Ostergaard
  Presented at MSM 2000. (MEMS)
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Impact Of Ball Via Configurations On Solder Joint Reliability In Tape Based Chip-Scale Packages [PDF]
  Bret Zahn
  "Three-dimensional finite element analysis has been applied to determine the time-dependent solder joint fatigue response of a tape based chip-scale package under accelerated temperature cycling." (Nonlinear, Anand)
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Average Rating: 8.8 (4 votes)  
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Meeting the Cost/Performance Requirements of Flex-Based Chip-Scale Packages
  Randy D. Schueller, Elizabeth A. Bradley, and Paul M. Harvey
  "An ANSYS two-dimensional, mechanical stress/strain model was created to compare a 12-mm flex BGA structure directly to the E-CSP in a board-level condition." (Nonlinear, plasticity)
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Average Rating: 10.0 (2 votes)  
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Micromachined Piezoelectric Ultrasonic Transducers Based On Parylene Diaphragm In Silicon Substrate
  Cheol-Hyun Han and Eun Sok Kim
  "This paper describes the techniques used in fabricating the transducers, their performance characteristics, and finite element analyses (FEA) with ANSYS 5.6. With ANSYS, we have calculated the stress and strain (under a static pressure load) and the dynamic mode shapes over a certain frequency range. Also, with appropriate piezoelectric matrices incorporated into the ANSYS batch model, a piezoelectric coupled-field analysis has been performed." (MEMS)
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Average Rating: 8.8 (12 votes)  
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Modeling Approach for CVD-Diamond-based Mechanical Structures [PDF]
  P. Schmid, M. Adamschik, S. Ertl, P. Gluche, and E. Kohn
  Analysis of diamond-based MEMS devices (instead of silicon) with ANSYS.
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Modeling MEMS Resonant Devices Over a Broad Temperature Range [PDF]
  Russell DeAnna, Shuvo Roy, Christian A. Zorman, Mehran Mehregany
  (from ANSYS Solutions magazine, volume 1, #2) (MEMS)
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Modeling of the Piezoelectric Micropump for Improving the Working Parameters [PDF]
  Oana Tatiana Nedelcu, Victor Moagar-Poladian
  A piezo micropump. Used ANSYS for analysis of deflection of pump. (MEMS)
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Modelling and Experimental Investigations on Degradation of Microcomponents in Power Cycling
  M. Thoben, W. Staiger, J. Wilde
  "Thermomechanical damage is one of the principal failure causes of microcomponents and microsystems. Often the basic defect mechanisms are crack initiation and subsequent crack propagation in interfaces or materials. The fatigue behavior of microcomponents can in many cases be described by the Manson-Coffin-Formula. This model is well-suited for comparison of different designs relative to each other but it will fail when a realistic lifetime prognosis is expected. Therefore we worked out a concept which is based on the computation of the strain range distribution in the interconnection by finite elements simulations and subsequent calculation of the cyclic crack propagation rate. Using this method in combination with calibration measurements it is possible to predict the lifetime of electronic assemblies with significantly improved precision compared to the Low-Cycle-Fatigue approaches."
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Nonlinear Mechanics of Suspension Beams for a Micromachined Gyroscope
  W. O. Davis and A. P. Pisano
  "We present a method for the calculation of the coefficients of cubic stiffening for tether-suspended micromachined systems. The analysis is based on a nonlinear rod theory, and enables the prediction of the maximum achievable motion amplitude prior to the onset of nonlinear behavior. The analysis is applied in detail to a microgyroscope. Comparisons with a finite element model and experimental data are used to validate the analysis, and issues pertaining to the optimal design of the gyroscope's suspension are investigated." (MEMS)
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Nonlinear-Time-Dependent Analysis of Micro Via-in-Pad Substrates for Solder Bumped Flip Chip Applications
  John H. Lau, S. W. Ricky Lee, Stephen H. Pan, and Chris Chang
  "An elasto-plastic-creep analysis of a low-cost micro via-in-pad (VIP) substrate for supporting a solder bumped flip chip in a chip scale package (CSP) format soldered on a PCB is presented in this study." (Nonlinear, Anand)
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Novel Horn Designs for Ultrasonic/Sonic Cleaning Welding, Soldering, Cutting and Drilling
  S. Sherrit, S.A. Askins, M. Gradziol, B.P. Dolgin, X. Bao, Z. Chang, and Y. Bar-Cohen
  "In this paper we will present a variety of novel horn designs, which overcome some of the limitations discussed above. One particular design that has been found to overcome these limitations is the folded horn. In this design the horn elements are folded which reduce the overall length of the resonator (physical length) but maintain or increase the acoustic length. In addition initial experiments indicate that the tip displacement can be further adjusted by phasing the bending displacements and the extensional displacements. The experimental results for a variety of these and other novel horn designs will be presented and compared to the results predicted by theory."
[ANSYS Piezoelectric, version unknown]
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Numerical Analysis of Plastic Encapsulated Electronic Package Reliability: Viscoelastic Properties of Underfill Resin
  Man-Lung Sham, Jang-Kyo Kim, Joo-Hyuk Park
  "The reliability and mechanical performance of electronic integrated circuit (IC) package is studied based on the finite element analysis."
ANSYS Nonlinear, version 5.7.
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Numerical And Analytical Modeling Of The Piezoelectric Transformer And Experimental Verification [PDF]
  S. Hallaert , E. Sarraute and B. Le Pioufle
  Use of ANSYS for modal analysis of miniature piezo transformer. (MEMS)
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Average Rating: 7.0 (5 votes)  
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Numerical Evaluation of Thermal Cycling Reliability of High Performance Flip-Chip Package Assembly Using Submodeling Analysis
  Chin-Li Kao, Yi-Shao Lai, and Tong Hong Wang
  "This paper applies the submodeling technique in analyzing thermal cycling reliability of high performance flip-chip ball grid array package assemblies. The packages have one-piece tunnel-type heat spreaders with different lead widths, connected to chips using different thermal interface materials. The global model contains no solder bumps to simplify the analysis. The calculated displacement field of the global model is then interpolated on the boundary of the submodel that contains the critical solder bump. The submodel is solved using the prescribed displacement boundary conditions together with external thermal loads to evaluate thermomechanical reliability of the critical solder bump."
ANSYS Nonlinear (Anand Model), version 7.0
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Numerical Simulations of Flat-walled Diffuser Elements for Valveless Micropumps [PDF]
  Anders Olsson, Goran Stemme, and Erik Stemme
  Use of ANSYS/Flotran for analysis of micropump. (MEMS)
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Average Rating: 10.0 (4 votes)  
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Optimal Design of Computer Experiments for the Generation of Microsystem Macromodels Using IMSET and Non-Parametric Fitting
  Selden B. Crary, Peter Cousseau, David Armstrong, David M. Woodcock, Olivier Dubochet, Philippe Lerc
  "We present a new and unique software program, IMSET, capable of finding optimal designs for computer experiments. A finite-element simulation of a micro-machined flow sensor was used to illustrate macromodel generation and to compare the quality of the IMSET design with other approaches."
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Optimization of a Circular Piezoelectric Bimorph for a Micropump Driver
  Christopher J. Morris and Fred K. Forster
  "Piezoelectric bimorph actuation has been successfully used in numerous types of microdevices, most notably micropumps. However, even for the simple case of circular geometry, analytical treatments are severely limited. This study utilized the finite-element method to optimize the deflection of a circular bimorph consisting of a single piezoelectric actuator, bonding material and elastic plate of finite dimensions. Optimum actuator dimensions were determined for given plate dimensions, actuator-to-plate stiffness ratio and bonding layer thickness." (PLANE13)
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Optimizing Board-level Reliability of an Underfilled, Stacked Chip Scale Package
  Zane E. Johnson, Nathan R. Schneck
  "Previously benchmarked finite-element (FE) models of a stacked chip scale package (CSP) are used to identify optimum underfill material properties under drop-impact and accelerated temperature cycling (ATC) stress conditions. The simulation sets indicate that an underfill having a modulus of 2–6 GPa and CTE of 25 ppm/K maximizes drop life and does no harm to ATC performance for both Sn63Pb37 and SAC305 solder joints. The methodology described can be applied to other package styles, material sets, and stress conditions."
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Overview of Reliability Models and Data Needs
  Ahmer Syed
  "Workshop on Modeling and Data Needs for Lead-Free Solders" (Amkor Presentation) Note that FEA pictures in presentation are ANSYS plots - Darveaux's data is based on Anand's Model (TB,ANAND), although ANSYS also allows for use of common creep laws such as hyperbolic sine and power law.
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Average Rating: 10.0 (2 votes)  
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Probabilistic Design System (PDS): A Realistic Approach of Finite Element Modelling for Capacitive Micro-machined Ultrasonic Transducers (cMUTS)
  Vamshi Kommareddy, Manoj Kumar, Ying Fan, James Barshinger
  "This paper represents a realistic approach for modeling a cMUT device. CMUTs have become very popular over the last decade because of the comparable bandwidth, sensitivity and dynamic range with its piezoelectric counterparts. The ease of fabrication is an added advantage. Modeling of CMUT is a coupled physics problem, which involves solving Electrostatics-Structural-Fluid interactions simultaneous. Finite Element models of the CMUT are constructed using the commercial code ANSYS (10.0). In the standard approach of modeling, from existing literature assumes deterministic values for design parameters, however fabrication of the device introduces some amount of variation in the design parameters. In this paper, the PDS FEM approach is discussed to account for the variability in fabrication. The results from the PDS approach on the performance characteristics like resonance frequency; collapse voltage and electromechanical coupling coefficient will be discussed."
[ANSYS PDS, version 10.0]
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PZT Actuated Micromirror For Nano-Tracking Of Laser Beam For High-Density Optical Data Storage [PDF]
  Youngjoo Yee, Hyo-Jin Nam, See-Hyung Lee, Jong Uk Bu, Young-Sam Jeon, and Seong-Moon Cho
  A piezo-actuated micromirror. Used ANSYS for stress and modal analysis of mirror. (MEMS)
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Average Rating: 5.0 (4 votes)  
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Quality Based Design and Design for Reliability of MEMS Using Probabilistic Methods [PDF]
  Stefan Reh, Paul Lethbridge, Dale Ostergaard
  Presented at MSM 2000. (MEMS)
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Quality Based Design from Probabilistic Methods [PDF]
  Stefan Reh, Paul Lethbridge, Dale Ostergaard
  (from ANSYS Solutions magazine, volume 2, #2) (MEMS)
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Reduced Order Modeling of Fluid Structural Interactions in MEMS Based on Modal Projection Techniques
  Jan Mehner, Wolfram Doetzel, Bernd Schauwecker, Dale Ostergaard
  This paper provides useful background information on the modal projection technique available in ANSYS with FLUID136 elements (RMFLVEC, DMPRAT, and ABEXTRACT macros). Although the ROM140 element has not been officially released (it is undocumented), this paper introduces that element as well.
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Reliability Study of Underfill/Chip Interface Under Accelerated Temperature Cycling (ATC) Loading
  Y.L. Zhang, D.X.Q. Shi, W. Zhou
  "Interface reliability issue has become a major concern in developing flip chip assembly. The CTE mismatch between different material layers may induce severe interface delamination reliability problem. In this study, multifunctional micro-moire´ interferometry (M3I) system was utilized to study the interfacial response of flip chip assembly under accelerated thermal cycling (ATC) in the temperature range of 40 C to 125 C. This in-situ measurement provided good interpretation of interfacial behavior of delaminated flip chip assembly. Finite element analysis (FEA) was carried out by introducing viscoelastic properties of underfill material. The simulation results were found to be in good agreement with the experimental results. Interfacial fracture mechanics was used to quantify interfacial fracture toughness and mode mixity of the underfill/chip interface under the ATC loading. It was found that the interfacial toughness is not only relative to CTE mismatch but also a function of stiffness mismatch between chip/underfill."
ANSYS Nonlinear (Viscoelasticity), version 6.1.
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Seismic Simulation Of The Motorola SC4812ET RF And Power Cabinets Using Pro/Engineer and ANSYS
  Alan Herda, D. Allan Daggs
  "To prevent earthquake test failure and reduce cycle time, mechanical development engineering conducted seismic simulations in parallel with the design of a new outdoor cellular base station and accompanying battery cabinet. Finite element models of the Motorola SC4812ET RF (Radio Frequency) and Power Cabinets, weighing 1400 pounds and 3500 pounds respectively, were built and subjected to Bellcore Zone 4 earthquake loading using ANSYS finite element analysis software."
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Average Rating: 8.6 (14 votes)  
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Semiconductor Package Simulations: Assembly, Test, and Reliability [PDF]
  Steven Groothuis
  This is a presentation which demonstrates various types of analyses ANSYS can perform which are applicable to the semiconductor industry.
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Average Rating: 7.5 (8 votes)  
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Simple APDL Implementation of a 3D FEM Simulator for Mutual Capacitances of Arbitrarily Shaped Objects Like Interconnects [PDF]
  Andreas Hieke
  Alternative download link here or here
See other publication by A. Hieke. I can't recall if this or the above article is referenced in ANSYS 5.6 Theory Manual. A variant article "Tiny Devices, Big Problems: Computation of Capacitance in Microelectric Structures" was published in the ANSYS Solutions magazine Vol 2 No 3.
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Simulation of Bellcore Testing of Electronics Cabinets for the Telecommunications Industry [PDF]
  Chris Andersen
  Various Bellcore tests performed with ANSYS.
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Structural and Thermal Analysis of a MEMS Angular Gyroscope
  Chris C. Painter and Andrei M. Shkel
  "This paper describes the structural and thermal modeling of a Micro Electro Mechanical System (MEMS) z-axis angular gyroscope. The gyroscope consists of a oscillating proof mass supported by a suspension made up of six concentric interconnected rings rigidly attached to an anchored frame. The device is capable of measuring angular displacement through precession of the proof mass line of oscillation in the presence of rotation induced Coriolis force. Using a strain energy method,a closed form solution for the effective stiffness of the suspension system is developed, which is confirmed using finite element modeling. A comparative study of the suspension with a commonly used serpentine spring suspension demonstrates that the studied device is robust to thermal fluctuations and residual stresses. A parametric analysis is used to identify an appropriate micromachining technology suitable for the fabrication of the angular gyroscope."
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The Numerical Analysis of Strain Behavior at the Solder Joint and Interface in a Flip Chip Package
  S.C. Chen, Y.C. Lin, C.H. Cheng
  "The aim of this study was to investigate the strain behaviors at the joint interface of a flip chip package during thermal cycling testing using a numerical method. Because the underfill and solder bump material properties exhibit a large non-linearity in the higher temperature range, the linear elastic assumption may lose accuracy during numerical analysis. This study compared the differences in interfacial stress or strain between the linear and non-linear material property assumptions. The viscoplasticity of the solder bump and temperature-dependent underfill properties were assumed in the non-linear analysis. The numerical results showed that the solder bump failure mechanism was a combination of fatigue and creep actions dominated by plastic shear strain. The tensile stress due to shrinkage and hardening in the solder joints in the low thermal cycle temperature dwell period could result in ablation at the joint interface."
ANSYS 5.6.1, Anand model
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The Thermo-Mechanical Stress Issues in a Thermally Enhanced QFP
  Jack G. Hwang, T. J. Huang, and J. J. Lee
  "A finite element model with multiple load steps for different processes is used to predict the stresses in die in a thermally enhanced QFP (HQFP)."
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Thermal Finite Elements Analysis of the BaBar Silicon Vertex Tracker
  D. Barni, D. Giugni, F. Lanni, F. Palombo
  "In this note we present nite elements calculations of the thermal behavior of the BaBar silicon vertex tracker. Layers 1-2, 3 and 5 have been studied. Results show the adequacy of the cooling system in keeping the front-end chips into their optimal working condition. Thermo-mechanical results of layers 1-2 are also presented."
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Thermal Modeling of the Infrared Reflow Process for Solder Ball Connect (SBC)
  H.V. Mahaney
  "A thermal model of the infrared reflow process has been developed for an FR-4 card populated with an array of Solder Ball Connect (SBC) modules. The analysis of the three-dimensional, transient, finite element model accounts for radiative exchange within the infrared oven and for the heat conduction (nonisotropic) within the modules and card. Transient temperature profiles of selected points and three-dimensional temperature distributions at selected times are presented to describe the primary heat-transport mechanisms. Numerical predictions and empirical data indicate that the SBC modules are relatively isothermal throughout the infrared reflow process. Therefore, every solder ball within the array exhibits a nearly identical thermal profile. This result is fortunate, since the inner solder ball connections cannot be visually inspected. The influence of module spacing and the ability to improve the reflow process by use of a high-emissivity cap coating are demonstrated."
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Thermomechanical Fatigue Failure of Interfaces in Lead-Free Solders
  M¨uge Erinc (Eindhoven University of Technology)
  "The European Union Waste Electrical and Electronic Equipment Directive (WEEE) and Restriction of Hazardous Substances Directive (RoHS) banned lead from electronic systems from July 1, 2006 onwards, which has led to much interest in leadfree solders in the past years. Among several lead-free solder alternatives, SnAgCu is a widely accepted replacement due to its better creep-fatigue resistance and microstructural stability. SnAgCu has been extensively studied in the past decade, however, there are still issues to be resolved concerning solder reliability, the underlying mechanisms of thermo-mechanical fatigue failure, fatigue life predictions and the overall effect of decreasing component size, driven by the ongoing miniaturization trend. This thesis aims to scientifically contribute to this subject by a coupled experimental-numerical approach."
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Time-Dependent Material Modeling for Finite Element Analyses of Flip Chips
  Frank Feustel, Steffen Wiese, Ekkehard Meusel
  "Finite element analyses (FEA) have established as effective method for reliability assessment of flip chip assemblies. The simulation results are significantly dependent on the selected material models. Regarding flip chip assemblies, this statement mainly applies to the tin lead solder of the flip chip joints and the encapsulant – the so-called underfill.
Comprehensive material data of eutectic solder were determined on real flip chip joints by TU Dresden. Based on these data three modeling approaches were evaluated (target platform was the FEA code ANSYS): viscoplasticity (Anand's model), power law creep (with 2 terms) + plasticity, and sinh law creep + plasticity (as user defined model in ANSYS)."

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Tooling up for Micro Electro Mechanical Systems [PDF]
  Dale Ostergaard
  (from ANSYS Solutions magazine, volume 2, #1) (MEMS)
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Transient Behavior of a Polymer Fill Material with Time Dependent Viscoelastic Properties
  John Thompson, Steven Groothuis, Hong Tang, Paul Koeneman
  "In an effort to simplify the implementation of viscoelastic material models into ANSYS, an ANSYS User-Programmable Feature (UsrFictive) has been modified to allow a more practical definition of viscoelastic material parameters. Standard ANSYS input of material data may be based upon temperature. Currently, ANSYS material data may not be a function of any other parameter. Many polymers used in industry are initially liquid and must be “cured” in a manufacturing process. This fact means that the properties will change over time. This application demonstrates one method of implementing a curing process simulation for a viscoelastic polymer."
[ANSYS Nonlinear, version 6.?]
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Underfill Constraint Effects during Thermo-Mechanical Cycling of Flip Chip Solder Joints
  I. Dutta, A. Gopinath, and C. Marshall
  "The presence of an 'underfill' encapsulant between a micro-electronic device and the underlying substrate is known to substantially improve the thermal fatigue life of flip-chip solder joints, primarily due to load-transfer from the solder to the encapsulant. In this study, a new single joint-shear (SJS) test, which allows the measurement of the strain response of an individual solder ball during thermo-mechanical cycling (TMC), has been utilized to investigate the impact of the constraint imposed by the underfill on a solder-joint. Finite element modeling has been utilized to demonstrate that the SJS sample geometry captures most of the deformation characteristics of a flip-chip joint, and to provide insight into the experimental observations."
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Using a Heat Transfer Analogy to Solve for Squeeze Film Damping and Stiffness Coefficients in MEMS Structures
  Dale Ostergaard, Jan Mehner
  This paper provides background information on using a heat transfer analogy to solve the Reynolds equation (squeeze film damping). Although ANSYS now has FLUID136 and FLUID138 to solve such problems, this paper can be useful in gaining a better understanding of these types of analyses.
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Validation of a General Fatigue Life Prediction Methodology for Sn-Ag-Cu Lead-Free Solder Alloy Interconnects
  David M. Pierce, Sheri D. Sheppard, Paul T. Vianco, Jerome A. Regent, J. Mark Grazier
  "A general fatigue life prediction methodology, based on a unified creep plasticity damage (UCPD) model, was developed for predicting fatigue cracks in 95.5Sn-3.9Ag-0.6Cu (wt %) solder interconnects. The methodology was developed from isothermal fatigue tests using a double-lap-shear specimen. Finite element analysis model geometries, mesh densities, and assumptions were detailed for both a full model (an octant-symmetry slice of the entire ball grid array (BGA) assembly) and a submodel (the solder joint deemed most likely to fail and the surrounding package layers) to facilitate fatigue prediction. Model validation was based on the thermal mechanical fatigue of plastic BGA solder joints (250-4000 thermal cycles, -55°C to 125°C, and 10°C/min). Metallographic cross sections were used to quantitatively measure crack development. The methodology generally underpredicted the crack lengths but, nonetheless, captured the measured crack lengths within a +-2X error band. Possible shortcomings in the methodology, including inaccurate materials properties and part geometries, as well as computational techniques, are discussed in terms of improving both the UCPD constitutive model and the fatigue life prediction methodology fidelity and decreasing the solution time."
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Vibration Prediction in Switched Reluctance Motors With Transfer Function Identification From Shaker and Force Hammer Tests
  Zhangjun Tang, Pragasen Pillay, and Avoki M. Omekanda
  "A vibration prediction model for the switched reluctance motor is constructed in this paper. Shaker and force hammer tests for vibration measurement are used for measuring crucial parameters like modal frequency and damping ratio for the transfer function. A detailed lookup table of normal force versus phase current and rotor angle is constructed based on finite-element calculations. The model is then verified by experiments, with acceptable accuracy."
[ANSYS Low-Frequency Electromagnetics, version unspecified]
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Viscoplastic Finite-Element Simulation To Predict The Solder Joint Fatigue Life Of Different Flash Memory Die Stacking Architectures
  Yong Je Lee
  "This thesis focuses on the viscoplastic finite-element simulation to predict the solder joint fatigue life of different die stacking architectures for flash memory products. Four different stacked package architectures were evaluated as follows: pyramid, rotated, and spacer stacking, while interconnection (solder joint) was held constant. Number of dies for all four stacking configurations were varied from three, five and seven. To keep the package height constant, the die and die attach thickness were varied and the resulting effects on the stresses were investigated. A quarter and half symmetry model of stacked flash package are generated using ANSYS APDL script. The life cycle of the resulting packages were simulated under accelerated temperature cycling conditions (-40C to +125C, 15min ramps/15min dwells)."
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Wire Bond Temperature Sensor
  Shivesh Suman, Michael Gaitan, Yogendra Joshi, George Harman
  "This work reports the first demonstration of a bond pad test structure with embedded thermopile sensors for the measurement of the transient temperature response during the wire bonding operation. This paper will present the design and operation of the bond pad test structure and show and discuss temperature measurements during the wire bonding operation."
[ANSYS Thermal, version unknown]
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