The objectives of this thesis are to develop and validate laser ultrasonic inspection methods for on-line testing of microelectronic devices. Electronic packaging technologies such as flip chips and BGAs utilize solder bumps as electrical and mechanical connections. Since they are located hidden from view between the device and the substrate, defects such as cracks, voids, misalignments, and missing bumps are difficult to detect using non-destructive methods. Laser ultrasonic inspection is capable of detecting such defects by utilizing a high power laser pulse to induce vibrations in a microelectronic device while measuring the out of plane displacement using an interferometer. Quality can then be assessed by comparing the vibration response of a known-good device to the response of the sample under inspection. The main limitation with the implementation of laser ultrasonic inspection in manufacturing applications is the requirement to establish a known-good reference device utilizing other non-destructive methods. My work will focus on developing a method to inspect flip chip devices without requiring a previously established reference. The method will automatically examine measurement data from a large sample set to identify those devices which are most similar. The selected devices can then be utilized to compose a hybrid reference signal which can be used for comparison and defect detection. Current trends in the electronic packaging industry continue to drive toward increased solder bump density, making it increasingly difficult to generate strong ultrasonic signals in these stiffer devices. To overcome this difficulty, I propose a new excitation method which places the source of ultrasound at the inspection location for each test point on the device surface. This ensures that the same power is available for each inspection location while also increasing the signal to noise ratio. The hardware implementation of this method reduces the system complexity and required automation, which can significantly reduce equipment cost and inspection time. The implementation of the proposed excitation method in conjunction with the use of a hybrid reference signal for defect detection will improve the utility of the laser ultrasonic inspection technique to on-line inspection applications where no other non-destructive methods are currently available.

Thesis (M.Sc.) - Carleton University, 2002. / Includes bibliographical references (p. 95-102). Also available in electronic format on the Internet.

Thesis (Ph.D.)--Rochester Institute of Technology, 2009. / Typescript. Includes bibliographical references (leaves 173-179).

Thesis (M. S.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2010. / Committee Chair: Jacobs, Laurence J.; Committee Co-Chair: Wang, Yang; Committee Member: Kim, Jin-Yeon. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Η εργασία αυτή εχεις ως αντικείμενο την μελέτη και την κατασκευή ενός μετατροπέα συντονισμού για την οδήγηση ενός πιεζοηλεκτρικού κινητήρα οδεύοντος κύματος τύπου Ultrasonic. Αρχικά γίνεται μια θεωρητική αναφορά στους πιεζοηλεκτικούς κινητήρες και τους ηλεκτρονικούς μετατροπείς ισχύος ενώ ακολουθεί η προσομοίωση του μετατροπέα στο Pspice. Ακολούθως αναλύεται η διαδικασία της κατασκευής και ακολουθούν τα πειραματικά αποτελέσματα καθώς και τα συμπεράσματα που λάβαμε. / In this thesis someone can find about designing and manufacturing a resonant inverter in order to control a piezoelectric traveling wave ultrasonic motor. In the first chapters someone can read about the piezoelectric phenomenon, piezoelectric motors and about electronic converters which control the velocity of motors. Next there is a presentation of the Pspice simulation model and results. Furthermore there is the manufacturing procedure of the inverter and at the end there are the results and conclusion of the thesis.

The accurate measurement of multiphase flows of oil/water/gas is a critical element of oil exploration and production. Thus, over the last three decades; the development and deployment of in-line multiphase flow metering systems has been a major focus worldwide. Accurate measurement of multiphase flow in the oil and gas industry is difficult because there is a wide range of flow regimes and multiphase meters do not generally perform well under the intermittent slug flow conditions which commonly occur in oil production. This thesis investigates the use of Doppler and cross-correlation ultrasonic measurements made in different high gas void fraction flow, partially separated liquid and gas flows, and homogeneous flow and raw slug flow, to assess the accuracy of measurement in these regimes. This approach has been tested on water/air flows in a 50mm diameter pipe facility. The system employs a partial gas/liquid separation and homogenisation using a T-Y junction configuration. A combination of ultrasonic measurement techniques was used to measure flow velocities and conductivity rings to measure the gas fraction. In the partially separated regime, ultrasonic cross-correlation and conductivity rings are used to measure the liquid flow-rate. In the homogeneous flow, a clamp-on ultrasonic Doppler meter is used to measure the homogeneous velocity and combined with conductivity ring measurements to provide measurement of the liquid and gas flow-rates. The slug flow regime measurements employ the raw Doppler shift data from the ultrasonic Doppler flowmeter, together with the slug flow closure equation and combined with gas fraction obtained by conductivity rings, to determine the liquid and gas flow-rates. Measurements were made with liquid velocities from 1.0m/s to 2.0m/s with gas void fractions up to 60%. Using these techniques the accuracies of the liquid flow-rate measurement in the partially separated, homogeneous and slug regimes were 10%, 10% and 15% respectively. The accuracy of the gas flow-rate in both the homogeneous and raw slug regimes was 10%. The method offers the possibility of further improvement in the accuracy by combining measurement from different regimes.

No description available.

Recent studies have indicated that vascular stiffness is an important predictor of future cardiovascular disease. Hence, assessment of vascular stiffness would be of interest. Ultrasound is a good modality for assessment of vascular stiffness, due to its hight temporal resolution and non-invasive nature. Using ultrasound, various techniques have been proposedto estimate vascular stiffness, one of them being Pulse Wave Imaging. The ultimate goal of Pulse Wave Imaging is to provide a robust, qualitative and quantitative method to estimate and visualize clinically important parameters and phenomenonfor cardiovascular disease. The objective of this thesis limits itself to 1) expand Pulse Wave Imaging by going beyond just the diastolic stiffness, 2) utilize Pulse Wave Imaging in an atherosclerotic swine model to monitor plaque initiation and progression and 3) improve non-linear stiffness estimation at or near sites of reflections using Pulse Wave Imaging for clinical applications. In Aim 1, the question pursued was whether Pulse Wave Imaging can be utilized to monitor this non-linear behavior in-vivo. It was observed that in this mouse model, the compliance at diastolic pressure did not change significantly, whereas the compliance at end-systole did. Thus suggesting that Pulse Wave Imaging was able to monitor a change in non-linear stiffness, and that considering this, might be of importance. In Aim 2, the ability of Pulse Wave Imaging to monitor disease progression for atherosclerotic disease progression was assessed. Since human studies involve various compounding factors, animal models provide the opportunity to study the ability of methods in a more controlled manner. Swine is a good candidate due to its similarity with humans. To doso, first, the feasibility of Pulse Wave Imaging in swine needed to be assessed. While the cardiovascular system might be similar, various other factors, such as the location and depth of the carotid differs. It was revealed that PWI was feasible in swine and that we were able to generate atherosclerotic lesions within 9-months. Subsequently the ability of Pulse Wave Imaging and Vector Flow Imaging to monitor atherosclerotic progression leading to different type of lesions was assessed. The in-vivo findings were compared with histology and nanoidentation. The results indicated that Pulse Wave Imaging was shown to be able to separate to different disease progression pathways leading to different type of lesions. Finally in Aim 3, lessons learned from the animal models were attempted to be addressed by developing a more reflection robust approach for localized non-linear stiffness estimation for clinical application. First, improvements were proposed to a previously developed inverse problem approach that can resolve reflections within the field of view by including information from the flow velocity. To expand the approach to include non-linearity and reflections that occur outside the field of view, a physics-based neural network approach was considered. This might be of importance since most plaques are located at sites of significant reflections, such as the bifurcation. Chapter 6 revealed that artificial significant sources of reflections hindered its ability for sub-cm scale localized compliance measurements as indicated by an immediate increase in the number of detected segments after the ligation was induced. The approaches was validated using simulated data and feasibility was shown in in-vivo examples. With new progress, new issues tend to arise. Finally, the purpose of this sub-aim is to utilize the technique and investigate whether or not it can in fact better differentiate between different clinically relevant groups. The findings revealed no significant improvement concerning the mean compliance estimated, but appeared more robust against outliers when only the plaque segment was assessed. In conclusion, the results shown in this dissertation indicate that Pulse Wave Imaging is a promising approach to assess non-linear stiffness estimation for monitoring of vascular disease. Furthermore, an new methodology was proposed and feasibility was shown, which could further improve localized and non-linear stiffness estimation at or near sources of significant reflections, and which can be used as a starting point for further development.

No description available.

No description available.