Failure Analysis Tools Research Articles

Effect of sparse basis selection on ultrasonic signal representation

Recently, adaptive sparse representations of ultrasonic signals have been utilized to improve the performance of scanning acoustic microscopy (SAM), a common nondestructive tool for failure analysis of microelectronic packages. The adaptive sparse representation of an ultrasonic signal is generated by decomposing it in a learned overcomplete dictionary using a sparse basis selection algorithm. Detection and location of ultrasonic echoes are then performed on the basis of the resulting redundant representation. This paper investigates the effect of sparse basis selection algorithms on ultrasonic signal representation. The overcomplete independent component analysis, focal underdetermined system solver (FOCUSS), and sparse Bayesian learning algorithms are examined. Numerical simulations are performed to quantitatively analyze the efficiency of ultrasonic signal representations. Experiments with ultrasonic A-scans acquired from flip-chip packages are also carried out in the study. The efficiency of ultrasonic signal representations are evaluated in terms of the different criteria that can be used to measure its performance for different SAM applications, such as waveform estimation, echo detection, echo location and C-scan imaging. The results show that the FOCUSS algorithm performs best overall.

The focused ion beam technique: A useful tool for pharmaceutical characterization

Focused ion beam (FIB) instrumentation, a hybrid of the scanning electron micrsocope, ion milling and computer-aided design systems, has special uses in the electronic and semiconductor industries as a tool for failure analysis and device development. This paper examines the pharmaceutical applications of the FIB, particularly microscopic analysis of microspheres. With the FIB, microsphere structures were peeled off, layer by layer, and the structure of each layer was simultaneously observed under scanning microscopy. The particles had a wrinkled but non-porous surface. Going deeper, some holes appeared, with size and numbers increasing toward the particle center. This unique method precisely investigated the inner structure of particles, layer by layer. Then, by FIB milling, samples were extracted with an accuracy of localization of 50 nm from specific parts of the microspheres and prepared to a 200 nm uniform thickness film for examination under transmission electron microscopy. The FIB method also has the potential for a wide range of other quantitative and qualitative analysis of dosage forms and materials.

Scanning Electron Microscopy with Ultra Low Acceleration Voltage for Nanotechnology(Failure Analysis Technique and Tools in the Nanotechnology Era)

Scanning Electron Microscopy with Ultra Low Acceleration Voltage for Nanotechnology(Failure Analysis Technique and Tools in the Nanotechnology Era)

Reliability Evaluation of Thin Gate Dielectric using Conductive Atomic Force Microscopy(Failure Analysis Technique and Tools in the Nanotechnology Era)

Reliability Evaluation of Thin Gate Dielectric using Conductive Atomic Force Microscopy(Failure Analysis Technique and Tools in the Nanotechnology Era)

Failure Localization Tool for OLED(Failure Analysis Technique and Tools in the Nanotechnology Era)

Failure Localization Tool for OLED(Failure Analysis Technique and Tools in the Nanotechnology Era)

Evaluation of Si-Device by SPM(Failure Analysis Technique and Tools in the Nanotechnology Era)

Evaluation of Si-Device by SPM(Failure Analysis Technique and Tools in the Nanotechnology Era)

Evaluation of Configurations of Nanoscale Silicon Devices by Scanning Tunneling Spectroscopy(Failure Analysis Technique and Tools in the Nanotechnology Era)

Evaluation of Configurations of Nanoscale Silicon Devices by Scanning Tunneling Spectroscopy(Failure Analysis Technique and Tools in the Nanotechnology Era)

Two Dimensional Dopant Pro filing in Silicon Devices by Electron Holography(Failure Analysis Technique and Tools in the Nanotechnology Era)

Two Dimensional Dopant Pro filing in Silicon Devices by Electron Holography(Failure Analysis Technique and Tools in the Nanotechnology Era)

Trends of LSI Technology in Nanometer Era(Failure Analysis Technique and Tools in the Nanotechnology Era)

Trends of LSI Technology in Nanometer Era(Failure Analysis Technique and Tools in the Nanotechnology Era)

Nonlinear Ultrasonic Method to Detect Micro-Delamination in Electronic Packaging

The linear ultrasonic technique has been extensively used as a powerful, non-destructive test tool for reliability testing and failure analysis of electronic packaging. This is used most often in the inspection of defects such as delaminations, voids, or cracks through use of a SAM (Scanning Acoustic Microscope). Then, as the reliability level that is required of electronic packaging becomes higher and the thickness of package becomes thinner, the possible defect which needs to be detected becomes smaller. In the conventional SAM, however it is very difficult to detect small defects less than m µ 1 . 0 , such as micro-delaminations. In order to solve such a problem, this paper proposes a nonlinear ultrasonic method, where the nonlinearity caused by the effect of crack-face interactions is considered. The basic concept of this method involves harmonic frequencies that are generated in the transmitted ultrasonic wave due to the partial contact at the interface of micro-delamination. As an evaluation index, the nonlinear parameter dependent on the amplitude of the second order harmonic frequency component is obtained by spectral analysis of the transmitted signal. Experimental results show that the nonlinear parameter has good correlation with the micro-gap and the proposed method can detect the micro-delamination even less than nm 1 .

Experimental Investigation on the Interface Properties Evaluation in Piezoelectric Layered Structures by Love Waves Propagation

The linear ultrasonic technique has been extensively used as a powerful, non-destructive test tool for reliability testing and failure analysis of electronic packaging. This is used most often in the inspection of defects such as delaminations, voids, or cracks through use of a SAM (Scanning Acoustic Microscope). Then, as the reliability level that is required of electronic packaging becomes higher and the thickness of package becomes thinner, the possible defect which needs to be detected becomes smaller. In the conventional SAM, however it is very difficult to detect small defects less than m µ 1 . 0 , such as micro-delaminations. In order to solve such a problem, this paper proposes a nonlinear ultrasonic method, where the nonlinearity caused by the effect of crack-face interactions is considered. The basic concept of this method involves harmonic frequencies that are generated in the transmitted ultrasonic wave due to the partial contact at the interface of micro-delamination. As an evaluation index, the nonlinear parameter dependent on the amplitude of the second order harmonic frequency component is obtained by spectral analysis of the transmitted signal. Experimental results show that the nonlinear parameter has good correlation with the micro-gap and the proposed method can detect the micro-delamination even less than nm 1 .

Delamination modelling in a double cantilever beam

The simulation of the delamination process in composite structures is quite complex, and requires advanced FE modelling techniques. Failure analysis tools must be able to predict initiation, size and propagation of delamination process. The objective of the paper is to present modelling techniques able to predict a delamination in composite structures. Four different ways of modelling delamination growth of a double cantilever beam test (DCB) are proposed. The first two approaches were based on a cohesive zone model: the interface being represented either by using delamination elements or non-linear springs. The idea of the third approach was to use a fracture mechanics criterion, but to avoid the complex moving mesh techniques it often implies. The interface between the two layers was simulated with solid elements representing the matrix, which were eliminated when their energy release rate exceeded the critical value. The energy release rate was computed using the virtual crack closure technique (VCCT). In the last approach, the interface behaviour was modelled by a tiebreak contact. Coincident nodes were tied together with a constraint relation and remained joined, until when the maximum interlaminar stresses was reached. Once this value was exceeded, the nodes associated with that constraint were released to simulate the initiation of delamination. The comparison of the results of the first three modelling techniques with experimental data showed that very good correlation was achieved. Poor results were obtained using tiebreak contact. It was due to the criterion used, since when the critical interlaminar stress was reached, the delamination was experienced before the critical energy release rate was reached.

Linking product functionality to historic failures to improve failure analysis in design

Prior research has shown that similar failure modes occur within products (or components) with similar functionality. To capitalize on this finding, a knowledge base-driven failure analysis tool, the function-failure design method (FFDM), has been developed to allow designers to perform failure mode and effect analysis (FMEA) during conceptual design. The FFDM can offer substantial improvements to the design process since it enhances failure analysis thus giving it the ability to reduce the number of necessary redesigns. The FFDM, however, is only as good as the knowledge base that it draws from, and one fundamental question that arises in using the FFDM is: at what level of detail should functional descriptions of components be encoded? This paper explores two approaches to populating a knowledge base with actual failure occurrence information from Bell 206 helicopters. Results indicate that encoding failure data using more detailed functional models allows for a more robust knowledge base. Interestingly however, when applying FFDM, high level descriptions continue to produce useful results when using the knowledge base generated from the detailed functional models.

Resolution improvement of acoustic microimaging by continuous wavelet transform for semiconductor inspection

Acoustic microimaging (AMI) is used as an important non-destructive tool in semiconductor reliability evaluation and failure analysis. As advanced microelectronic packages are being produced smaller and thinner, detection of the internal features and defects in the packages is approaching the resolution limits for conventional AMI. To meet this challenge, an acoustic time–frequency domain imaging technique is proposed in this paper, which utilizes the excellent time–frequency localization characteristics of the continuous wavelet transform (CWT) to improve the axial resolution of AMI, without increasing acoustic frequencies. The proposed technique is compared to time domain AMI, frequency domain AMI and sparse signal representation based AMI (SSRAMI) with respect to both axial resolution and robustness. Simulation results show that the proposed technique has superior performance compared to time domain and frequency domain AMI techniques, and has close performance to SSRAMI but with less computation load.

Investigation of carbon void defects on hard disk surfaces

A carbon void on a hard disk surface is a defect that occurs during the carbon sputter deposition process for the manufacture of hard disks. Because the carbon overcoat on hard disk surfaces acts as a barrier to corrosion, it is essential to reduce the number and size of carbon voiddefects. In the present study, carbon void defects on hard disk surfaces were studied using various failure analysis tools. The influence of the substrate bias voltage on the number and size of carbon void defects was also investigated. The results of the failure analysis show that there wasa 40–50% loss in recorded magnetic bit signal due to an increase in the gap between a recording head and a hard disk surface with carbon void defects. Removing the bias voltage on the substrate during the sputtering process reduced the carbon void defects significantly. The average numberof carbon void defects per disk surface was reduced from 4 to 0·5. In addition, the average size of the carbon void defect was reduced from 8 μm to 3·8 μm.

単結晶Ｎｉ基超合金中のセル状変質域形成に対するマイクロメカニクス的アプローチ

A cellular microstructure may be nucleated in single crystal Ni-based superalloys when they have experienced a local damage associated with a plastic deformation during their in-service and post-service periods of gas turbine. In this work, an analytical method to investigate the morphological evolution in the cellular microstructure is proposed. The method is essentially based on the Eshelby's micromechanics theory, and it has been extended so as to be applied for material system containing high volume fraction inclusions, by employing the average stress field approximation by Mori and Tanaka. This method enables us to estimate a stable shape of precipitate in the material system, which must be influenced by many factors : e.g. precipitate volume fraction ; Young's modulus ratio and lattice misfit between matrix and precipitate ; external stress field in multi-axial state ; and heterogeneity of plastic strain between matrix and precipitate. A series of numerical calculations were summarized on the stable shape maps. The application of the method to predict the γ' rafting in superalloys during creep showed that the proposed method supplied reasonable explanations to all the experimental observations, and that the heterogeneity of plastic strain between matrix and precipitates may play a significant role in the shape stability of the precipitate. Furthermore, the method could successfully estimate the morphology in the cellular microstructure formed around the spherical indentation in CMSX-4 single crystal Ni-based superalloy. The present method will be a useful tool for failure analysis of superalloy components and for an estimation of in-service stress state.

Failure Analysis as an Essential Component of an SOFC Development Program

Post-test analysis provides the stack and materials development teams with valuable feedback after each test. Prototype systems, stacks and single cells are taken apart following a standard procedure to capture all relevant information. Those observations lead to a root cause analysis of the failure of either stack or single cell. Hence a loop is created, linking every activity of the program from research and development, pilot plant production, testing and back to research and development. Failure analysis tools Failure Modes and Effect Analysis (FMEA) and Fault Tree Analysis (FTA) provide support for root cause analysis. The analysis itself is performed by a standard set of autopsy procedures, scanning electron microscopy (SEM) and possibly x-ray diffraction (XRD). A collection of information is then grouped and trends are noted and related to the performance of cell, stack or prototype systems. Learning and recommendations are recorded and implemented. Failure analysis is the activity that closes the loop of the development program cycle.

Integrated Thermal and Optical Analyses of Phase-Change Optical Disk

An integrated analysis system based on thin film optics, thermal transfer and electromagnetics is developed. Thermal conductivity and generated heat are discussed for mark formation. The simulations of multilayer calorific sources and multibeam heating sources using the finite element method (FEM) are investigated. The readout of nanometer-scaled marks based on computational electromagnetics using the finite-difference time-domain (FDTD) analysis is discussed. The real marks captured with microscopes can be analyzed using this integrated analysis system combined with digital image technology. Material models in the electromagnetic vector method are discussed with reference to different layers of disk. It provides a powerful tool for structure design and failure analysis of phase-change optical disks.

Challenges facing independent multihospital healthcare technology management systems.

Independent, multihospital clinical engineering organizations have existed for 30 years. The clinical engineering profession has changed its focus over this time from equipment safety and control to healthcare technology management. Challenges faced by the professional have included cost pressures, outsourcing, and medical device industry changes. This paper describes an enduring independent, nonprofit, multihospital clinical engineering organization, the Technical Services Program (TSP) at the University of Vermont, which shows a successful adaptation to challenges. As part of TSP's five-year strategic plan, a strategy for changing these challenges into opportunities is part of the goal. Our clinical engineers have to be fluent in both information technology and biotechnology, follow trends in patient care technology and act accordingly, understand new customers and effectively deal with their technology problems, partner with manufacturers in technology support and planning, use failure analysis tools to effectively reduce technology-related patient incidents, and understand business and quality principles and apply them to make healthcare more cost effective. Current and future healthcare system changes are opportunities for the profession and fit well into the independent, multihospital mission of TSP.

Wavelet analysis based deconvolution to improve the resolution of scanning acoustic microscope images for the inspection of thin die layer in semiconductor

Scanning acoustic microscopy (SAM) is used as an important non-destructive test tool in semiconductor reliability evaluation and failure analysis. However, inspection of thin die layer has proven difficult as the reflected signals from the die top and bottom are superimposed. Conventional deconvolution techniques have been used for the improvement of time resolution in A-scan signal, however, they are not effective for SAM signal because the waveform of the reflected echo is quite different from the incident waveform due to the frequency dependent attenuation and the focal effect. In this paper, in order to overcome this difficulty, a new signal processing method, wavelet analysis based deconvolution technique is proposed. Its validity is approved by computer simulations and practical performances are demonstrated by experiments for the fabricated semiconductor sample.