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Presented by Lee Chean Shen General Engineering Research Institute Electronic and Ultrasonic Engineering Group Supervisors Prof. Dave Harvey Dr. Guangming.

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Presentation on theme: "Presented by Lee Chean Shen General Engineering Research Institute Electronic and Ultrasonic Engineering Group Supervisors Prof. Dave Harvey Dr. Guangming."— Presentation transcript:

1 Presented by Lee Chean Shen General Engineering Research Institute Electronic and Ultrasonic Engineering Group Supervisors Prof. Dave Harvey Dr. Guangming Zhang 22 January 2010

2 What is Acoustic? Longitudinal wave which consists of compression and dilation Human Hearing 20Hz20kHz100kHz Animal Navigation & Communication SeismologyMedical Diagnostics. Destructive & Non Destructive tools. AudibleInfrasoundUltrasound Destructive Ultrasound (>10 W/cm 2 ) Sonochemistry Welding Cleaning Cell Disruption Kidney Stone Removal Non-Destructive Ultrasound (0.1 – 0.5 W/cm 2 ) Flaw detection Medical Diagnosis Sonar Chemical Analysis

3 What is Acoustic Microscopy Imaging (AMI)? Non-Destructive technique Sensitive to voids, delaminations and cracks Detects flaws down to sub-micron Image nontransparent solids or biological materials Study microstructures of specimen X-Ray AMI Unreflowed Solder Bump, AMI presents better contrast of defect

4 Resolution characteristics of AMI technique. Increasing frequency largely lowers depth penetration Attenuation usually increase with frequency Lower frequency reduces resolution 230MHz50MHz More information captured

5 AMI Operational Characteristics - Transducer Transducer is cut/tuned to specific frequency, typically three types; Piezoelectric High frequency, low power (MHz region) Voltage applied to crystal, medium required Transducer is cut to frequency Magnetostriction (EMAT) Metal core responds to magnetic field Material dependant, no coupling required Photoacoustic Pulsed laser applied to specimen Thermal wave phenomena Very high frequency Measures material properties

6 Tranducer lensed to modify beam focus Ansys Model Construction (results in Review section) AMI Operational Characteristics - Medium

7 EMAT only applicable to specific materials Photoacoustic may require protective layer Piezoelectric - Couplant required Usually deionized water Reflection occurs at the interface between two mediums Air has low acoustic Impedance (Z) Z = ρV = density * sound velocity of medium Water to Steel ratio ~ 20:1 Air to Steel ratio ~ 100,000:1 (near 100% energy reflected) Pulse Echo Change in Impedance (Interface)

8 AMI Operational Characteristics - Configuration Two typical methods Pulse Echo – Image derived from reflections (Popular) Through Transmission – Image derived from received signal Through Transmission Pulse Echo Gate

9 Current issues facing AMI Electronic packages are shrinking and/or stacking Technique is approaching resolution limits Image processing techniques not broadly reliable Transducers have relatively narrow operational frequencies Optimal frequency difficult to determine

10 Nonlinear acoustic Imaging 2 nd order harmonic provides higher resolution Common in medical acoustics Require single frequency transducer Penetration depth proportional to fundamental wave Not all material generate harmonic waves Generated waves needs to reach receiver Explore implementation on stacked (3D) die

11 Clarify defect detection mechanism Limited published literature regarding subject Primary focus on new generation 3D IC packages Understand acoustic performance within 3D IC packages Balance optimum resolution vs. penetration Analyze defect detection mechanism of engineered faults

12 What is Ansys? Finite Element Multiphysics Simulation Software Accurate simulation of complex coupled-physics behaviour Broadly defined into two interface Ansys Mechanical APDL Ansys Workbench Structural Mechanics Explicit Dynamics Electromagnetics Fluid Dynamics Acoustics ETC

13 What is Finite Element Method? Complete system is distributed into a large number of discreet elements Complex system of nodes which form mesh grids Mesh grid contain material and structural properties Area anticipating stress/load tend to have higher density of node Mesh resolution increases computational time

14 Comparison of Mesh Resolution Models usually tested with multiple mesh resolution/configuration Ensure circular areas are adequately smooth/circular Mesh resolution and type fits geometry size Generally look right, results largely determined by mesh quality Fine Mesh Coarse Mesh Fine Mesh Coarse Mesh Tetrahedral (triangular) Hexahedral (square)

15 Also known as; Ansys Classic Old Ansys Reliant mostly on command lines and scripts Primitive GUI What is Ansys Mechanical APDL ?

16 What is Ansys Workbench? Ansys with user friendly GUI Idiot-proof Ansys Powerful module based project assembly/management

17 Transducer Simulation – Pressure Magnitude 1500m/s (water medium) Ansys APDL Mirror Result MirrorResult Side Lobes Main Lobes

18 Node reaction to applied load PCIRC,0,1,0,90 RECTNG,0,0.025,0,0.1 CYL4,0,0.25,0.2 (double radius) pcirc,0,1,0,90 RECTNG,0,0.025,0,0.1 CYL4,0,0.15,0.1 Expected shift of focus point Transducer Simulation – Acoustic Lens 1500m/s (water medium) Triangular 15 elements per wave

19 Scale up transducer simulations to MHz region Validate simulation with measured results Implement Non-Linear simulation General simulation cleanup Introduce materials into focused region Study acoustic defect detection mechanism


21 Eindhoven University of Technology The Principles of Medical Ultrasound HyperPhysics Utrasound Guide – Georgia State University CALCE – University of Maryland Acoustic Microscopy Guide – University of Hawaii Resolution improvement of acoustic microimaging by continuous wavelet transform for semiconductor inspection – LJMU GERI Guang-Ming Zhang, David M. Harvey, Derek R. Braden. The NDE Analysis of Tension Behaviour in Nicalon/SiC Ceramic Matrix Composites Jeongguk Kim, Peter K. Liaw, Hsin Wang Fundamentals of Ultrasonic Imaging and Flaw Detection – National Instruments Phased Array Tutorial - Olympus About HIFU – Maple Leaf HIFU Finite-element method – McGill University Introduction to Finite Element Analysis – Virginia Tech Modeling and Meshing Guide, Chapter 7 – Ansys

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