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Reliability testing and failure modelling is crucial and very challenging for modern electronics, especially safety critical electronics-based systems working under harsh environmental conditions. In this paper, an approach based on ultrasonic Non-Destructive Evaluation (NDE) is proposed to establish a failure model for solder joints which is urgently needed for prognostic and health management of electronics. Printed Circuit Boards (PCB) containing flip-chip and Area Array packages were designed and aged using Accelerated Thermal Cycling (ATC) testing. During ATC testing solder joint degradation was regularly monitored by taking out the test boards from the temperature chamber at four thermal cycle intervals for ultrasonic micro-imaging. Data pre-processing techniques including dynamic range-based intensity normalization, gain compensation, and calibration for random transducer defocusing errors were developed to enhance the data consistency, integrity and accuracy. Furthermore, solder joint image labelling and segmentation methods were developed by exploiting the geometrical features of the solder joints to extract individual solder joints and Region of Interests (ROIs) from the sequential ultrasound images collected throughout the testing. The mean intensity of the ROIs was used as the precursor to degradation to build the solder joint failure model, from which cycles to failure for individual solder joints are finally derived for life prediction. [ABSTRACT FROM AUTHOR]

Abstract: In a highly competitive market, reliable techniques for manufacturing quality control of electronic devices are demanded. Characterisation of modern microelectronic package integrity becomes more difficult due to the continued miniaturisation of electronic device and the complexity of advanced micro-assembling technologies such as chip-scale packages and 3D IC stacks. In this paper, sparse representations of acoustic signals are sought to improve the scanning acoustic microscopy (SAM), a common non-destructive tool for failure analysis of microelectronic packages. Sparse representation of an ultrasonic signal is obtained by decomposing it in an overcomplete dictionary. Detection and location of ultrasonic echoes are then performed on the basis of the resulting redundant representation. The method offers a solution to the deconvolution problem for restoration of the ultrasonic reflectivity function. It can restore closely space overlapping echoes beyond the resolution of the conventional SAM system. It also produces high resolution and accurate estimates for ultrasonic echo parameters, i.e., time-of-flight, amplitude, centre frequency, and bandwidth. These merits of the proposed method are explored in various potential applications for microelectronic package characterisation. [Copyright &y& Elsevier]

Abstract: 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. [Copyright &y& Elsevier]