M. Pecht - Profile on Academia.edu (original) (raw)
Conference Papers - 2007 by M. Pecht
— This paper presents an enhanced prognostic model to predict remaining useful life. The model ut... more — This paper presents an enhanced prognostic model to predict remaining useful life. The model utilizes environmental loads and in-situ performance measurements in conjunction with two baseline prediction algorithms: life consumption monitoring (LCM) and uncertainty adjusted prognostics (UAP). Fusion techniques are then utilized to integrate the two prognostic algorithms. A key and unique value of this combined prognostic model is its ability to assess intermittent as well as " hard " failures. In the paper we show how it has been validated for intermittent and " hard " solder joint interconnect failures under temperature cycling loads. 1
Papers by M. Pecht
Ensemble of Unsupervised Fuzzy C-Means Clustering Models for Classifying the Health Status of Oil Sand Pumps
Lecture Notes in Mechanical Engineering, 2013
Analog circuits have been widely used in diverse fields such as avionics, telecommunications, hea... more Analog circuits have been widely used in diverse fields such as avionics, telecommunications, healthcare, and more. Detection and identification of soft faults in analog circuits subjected to component variation within standard tolerance range is critical for the development of reliable electronic systems, and thus forms the primary focus of this paper. In this paper, we have experimentally demonstrated a reliable and accurate (99%) fault diagnostic framework consisting of a sweep signal generator, spectral estimator and a least squares-support vector machine. The proposed method is completely automated and can be extended for testing other analog circuits whose performances are mainly determined by their frequency characteristics.
Design for Reliability of Printed Circuit Boards
A well designed product satisfies performance requirements and optimizes between reliability, pro... more A well designed product satisfies performance requirements and optimizes between reliability, producibility, supportability and cost criteria. In the design of electronics, these design criteria originate from a variety of disciplines. Electrical criteria include meeting signal distribution, power distribution, board I/O, and grounding rules, reducing crosstalk, and minimizing routing track lengths to meet speed and transmission line specifications. Environmental criteria include meeting environmental derating limits. Mechanical criteria involve designing for durability under vibrational and thermalmechanical loading. Manufacturing criteria include meeting geometric constraints for quality control, and providing acceptable assembly conditions
A model for moisture induced corrosion failures in microelectronic packages
IEEE Transactions on Components, Hybrids, and Manufacturing Technology, 1990
ABSTRACT As integrated circuit geometries become smaller and package sizes and I/O counts increas... more ABSTRACT As integrated circuit geometries become smaller and package sizes and I/O counts increase, there is an increased potential of failures resulting from moisture ingress and corrosion. To aid in reliability prediction, design for reliability, and assessing reliability tradeoffs, a methodology for coupling the mechanisms of moisture ingress and corrosion in microelectronic packages into a first-order failure-rate model is presented. The model focuses on aluminum metallization corrosion resulting from chlorine-based contaminants, but is general enough to be applied to other cases
Circuit World, 1999
This paper presents the defects that occur during the assembly and manufacturing of solder joints... more This paper presents the defects that occur during the assembly and manufacturing of solder joints in single‐sided insertion‐mount printed wiring boards (PWBs). Each type of defect is discussed, with particular focus on how these defects are related to solderability issues, the mechanisms of failure due to defect‐induced failure accelerators, and the effect of the defect on solder joint reliability.
MilSpecs - To Be Or Not To Be
IEEE Transactions on Reliability, 1996
ABSTRACT First Page of the Article
Proceedings of 16th IEEE/CPMT International Electronic Manufacturing Technology Symposium
This report summarizes the status of electronic manufacturing and packaging technology in JTEC/WTEC
Reliability and failure analysis of Lithium Ion batteries for electronic systems
2012 13th International Conference on Electronic Packaging Technology & High Density Packaging, 2012
ABSTRACT This paper presents an investigation into the reliability and physical degradation mecha... more ABSTRACT This paper presents an investigation into the reliability and physical degradation mechanisms associated with the loss of battery performance. Cells from two different manufactures underwent cycle life testing until failure (defined as a 20% decrease in nominal capacity). Designated samples from each battery type were subjected to one of two different discharge methods, one at a constant discharge rate of 1C and the other at a constant discharge rate of 0.5C. A third group of batteries were collected and examined after undergoing catastrophic failure in field applications. The tape pull test (to test adhesion/cohesion of electrode material to current collectors) is introduced for the first time in battery literature. Other analysis techniques such as x-ray imaging and environmental scanning electron microscopy were used to investigate the structural and chemical degradation of all the samples. Statistical analysis was performed on the cycle life data to evaluate battery reliability.
Effects of Re-finishing of Terminations by Solder-Dipping on Plastic Quad Flatpack Electronic Parts
2005 7th Electronic Packaging Technology Conference
Tin whiskering is a concern with high tin finishes on electronic part terminations. Solder-dippin... more Tin whiskering is a concern with high tin finishes on electronic part terminations. Solder-dipping is being used as a method for replacing the original finish with eutectic tin-lead solder, as a tin whisker risk mitigation method. The solder-dipping process however, may expose the electronic parts to additional risks due to the the finish quality and thermal shock produced by the
Predicting the Reliability of Electronic Products
2007 8th International Conference on Electronic Packaging Technology, 2007
Reliability is the ability of a product or system to perform as intended (i.e., without failure a... more Reliability is the ability of a product or system to perform as intended (i.e., without failure and within specified performance limits) for a specified time, in its life-cycle environment. Commonly-used electronics reliability prediction methods (e.g. Mil-HDBK-217, 217-PLUS, PRISM, Telcordia, FIDES) based on handbook methods have been shown to be misleading and provide erroneous life predictions, a fact that led the U. S. military to abandon their electronics reliability prediction methods. The use of stress and damage models permits a far superior accounting of the reliability and the physics-of-failure, however sufficient knowledge of the actual operating and environmental application conditions of the product are still required. This paper presents a physics-of-failure based prognostics and health management approach for effective reliability prediction. The procedure includes failure modes, mechanisms, and effects analysis, data reduction and feature extraction from the life cycle loads, damage accumulation, and assessment of uncertainty.
2008 International Conference on Electronic Packaging Technology & High Density Packaging, 2008
The aim of qualification is to verify whether a product meets or exceeds the reliability and qual... more The aim of qualification is to verify whether a product meets or exceeds the reliability and quality requirements of its intended application. Qualification plays an important role in the process of product development. It can be classified by its specific purpose at different stages of the product development process. In this paper, a new methodology of product qualification is proposed based on physics-of-failure. This methodology consists of: product configuration and material information collection; application requirement information collection; strength limits and margins; failure modes, mechanisms and effects analysis; definition of qualification requirements; qualification test planning; testing; failure analysis and verification; and quality and reliability assessment. This approach to qualification ensures that it successfully addresses the failure mechanisms applicable to the product's specific design, manufacture, and application conditions.
Handbook of Performability Engineering
Miniaturization of electronics, reduction of time to market and new functionalities in the curren... more Miniaturization of electronics, reduction of time to market and new functionalities in the current context of autonomous driving, electrification and connectivity, are bringing new reliability challenges. Prognostics and Health Management (PHM) can be used effectively to address some of the key challenges, in particular new challenges associated with the transfer of consumer electronics to automotive industry. The concept of PHM is not new, but its application to electronic systems is relatively new. It is expected that the PHM demand for electronic systems would continuously increase as autonomous driving is being realized. This paper attempts to summarize the recent studies in the system-level PHM of electronic systems. Condition monitoring (CM) techniques and prognostics methods used for the PHM of electronic systems are reviewed first. Various implementation examples are followed using different system classifications. The findings from this review is expected to offer a technical summary of accomplishments and challenges during the course of applying PHM for electronic systems, and to identify future research tasks to be performed to make the PHM a more viable tool for reliability assessment of electronic systems.
IEEE Transactions on Device and Materials Reliability, 2012
High-power white light-emitting diodes (HPWLEDs) have attracted much attention in the lighting ma... more High-power white light-emitting diodes (HPWLEDs) have attracted much attention in the lighting market. However, as one of the highly reliable electronic products which may be not likely to fail under the traditional life test or even accelerated life test, HPWLED's lifetime is difficult to estimate by using traditional reliability assessment techniques. In this paper, the degradation-data-driven method (DDDM), which is based on the general degradation path model, was used to predict the reliability of HPWLED through analyzing the lumen maintenance data collected from the IES LM-80-08 lumen maintenance test standard. The final predicted results showed that much more reliability information (e.g., mean time to failure, confidence interval, reliability function, and so on) and more accurate prediction results could be obtained by DDDM including the approximation method, the analytical method, and the two-stage method compared to the IES TM-21-11 lumen lifetime estimation method. Among all these three methods, the two-stage method produced the highest prediction accuracy.
Measurements based on DC resistance have traditionally been used to monitor the reliability of el... more Measurements based on DC resistance have traditionally been used to monitor the reliability of electronic products. Unfortunately, DC resistance is not useful for detecting intermediate stages between a short and an open, such as a partially degraded interconnect. Under cyclic loading conditions, interconnect degradation is caused by fatigue cracking, which often initiates at the surface where the strain range is maximized. At high operating frequencies, signal propagation is concentrated at the circumferential region of an interconnect due to the skin effect. Therefore, RF impedance analysis offers a more sensitive means of detecting interconnect degradation than DC resistance. The skin effect also has implications for the reliability of electronics used in applications such as radar and telecommunications. The use of higher frequencies will make these circuits increasingly susceptible to performance degradation as a result of small cracks or deformation that would go unnoticed in ...
Journal of Intelligent Material Systems and Structures, 2011
This paper presents the application of model-based and data-driven approaches for prognostics of ... more This paper presents the application of model-based and data-driven approaches for prognostics of failures in embedded planar capacitors. An embedded planar capacitor is a thin laminate that serves both as a power/ground plane and as a parallel plate capacitor in a multilayered printed wiring board. These capacitors have gained importance with an increase in the operating frequency and a decrease in the supply voltage in electronic circuits since they can enable miniaturization of electronic circuits as well as improved electrical performance. In next generation electronic circuits, embedded planar capacitors will be crucial in communication, automotive, military, medical, and space applications. The capacitor laminate used in this study consisted of an epoxy-barium titanate nanocomposite dielectric sandwiched between Cu layers. Three electrical parameters, capacitance, dissipation factor, and insulation resistance, were monitored in situ during testing under elevated temperature and...
Popcorning in PBGA Packages During IR Reflow Soldering
Microelectronics International, 1997
Plastic ball grid arrays (PBGAs) have been gaining increasing industry acceptance as potentially ... more Plastic ball grid arrays (PBGAs) have been gaining increasing industry acceptance as potentially the lowest cost packages for high pin count applications. The main factors for their success include the inherent low cost of plastic packages, the high yields achievable with existing assembly equipment, the density advantages of an area array and, in many cases, superior electrical performance. The reliability of these packages with respect to solder joint fatigue has been extensively studied; however, little has been published on their reliability with respect to moisture‐related failure mechanisms during assembly, such as popcorning. In this study, two types of plastic ball grid array packages, a 225‐lead full matrix array and a 256‐lead perimeter array, which were preconditioned by baking at 125°C for 24 hours followed by exposure to 85°C and 30% relative humidity for 168 hours, were then subjected to three passes of simulated infra‐red reflow at 1°C/s and 0.67°C/s. Subsequent exami...
Accelerated testing and finite element analysis of PBGA under multiple environmental loadings
To investigate the long term reliability of plastic ball grid array (PBGA) packages in aerospace ... more To investigate the long term reliability of plastic ball grid array (PBGA) packages in aerospace applications, accelerated tests were conducted to non-underfilled and underfilled packages under multiple environmental loadings at board level. This paper discusses the test results and the underfill effect on solder joint reliability. Failure modes and sites were identified through failure analysis on test samples. To better understand the thermomechanical behavior of PBGAs under cyclic thermal loading environments, three dimensional FEA models for non-underfilled and underfilled packages were also developed and used to predict the time to failure.
Application of FPGA units in combined temperature cycle and vibration reliability tests of lead-free interconnections
2008 2nd Electronics Systemintegration Technology Conference, 2008
ABSTRACT According to the European Directive 2002/95/EC RoHS solders that contain lead have to be... more ABSTRACT According to the European Directive 2002/95/EC RoHS solders that contain lead have to be replaced with lead-free equivalents. Replacing well-known materials with new materials not only force technological adaptations but also force necessity of reliability investigations, especially new failure modes. In case of lead-free solders, the main problem is reduction of solder joint strength. Lower strength of lead- free solder joint in comparison with SnPb is the result of defects that occur in the joint structure. Because of local defects, the joints are much more sensitive for stresses, Stress inducted within the area of solder joint can lead to joint fractures. Despite the crack occurrence, the solder joint can still conduct electrically. Nevertheless cracked joint should be treated as failed because it does not fulfill its constructional function. Such failures can be difficult to detect in static conditions, but can be easy detected, when the tested joint is subjected to vibrations. During vibrations short opens of the joint can occur. Additional high temperature or temperature cycles loadings can make detection easier by acceleration of crack occurrence. To detect short opens of solder joints subjected to vibrations, continuous fast measurements of resistance changes during the test are required. Within the article, the essence of fast multi-channel measurements and the construction of dedicated data storage system will be described. As a summary expected results of measurements will be shortly presented.
Rolling element bearing fault detection: Combining energy operator demodulation and wavelet packet transform
2011 Prognostics and System Health Managment Confernece, 2011
Abstract Rolling element bearing vibration signal is a modulated signal, and the existence of mod... more Abstract Rolling element bearing vibration signal is a modulated signal, and the existence of modulation increases the difficulty in bearing fault detection. Hilbert transform has been widely used in signal demodulation. However, the endpoint effect often makes the result unsatisfactory. Further, bearing vibration signals are usually polluted by various noises at low frequency, and the analysis of high frequency can be more effective for bearing fault feature extraction. This paper proposes an improved method that combines the energy ...
— This paper presents an enhanced prognostic model to predict remaining useful life. The model ut... more — This paper presents an enhanced prognostic model to predict remaining useful life. The model utilizes environmental loads and in-situ performance measurements in conjunction with two baseline prediction algorithms: life consumption monitoring (LCM) and uncertainty adjusted prognostics (UAP). Fusion techniques are then utilized to integrate the two prognostic algorithms. A key and unique value of this combined prognostic model is its ability to assess intermittent as well as " hard " failures. In the paper we show how it has been validated for intermittent and " hard " solder joint interconnect failures under temperature cycling loads. 1
Ensemble of Unsupervised Fuzzy C-Means Clustering Models for Classifying the Health Status of Oil Sand Pumps
Lecture Notes in Mechanical Engineering, 2013
Analog circuits have been widely used in diverse fields such as avionics, telecommunications, hea... more Analog circuits have been widely used in diverse fields such as avionics, telecommunications, healthcare, and more. Detection and identification of soft faults in analog circuits subjected to component variation within standard tolerance range is critical for the development of reliable electronic systems, and thus forms the primary focus of this paper. In this paper, we have experimentally demonstrated a reliable and accurate (99%) fault diagnostic framework consisting of a sweep signal generator, spectral estimator and a least squares-support vector machine. The proposed method is completely automated and can be extended for testing other analog circuits whose performances are mainly determined by their frequency characteristics.
Design for Reliability of Printed Circuit Boards
A well designed product satisfies performance requirements and optimizes between reliability, pro... more A well designed product satisfies performance requirements and optimizes between reliability, producibility, supportability and cost criteria. In the design of electronics, these design criteria originate from a variety of disciplines. Electrical criteria include meeting signal distribution, power distribution, board I/O, and grounding rules, reducing crosstalk, and minimizing routing track lengths to meet speed and transmission line specifications. Environmental criteria include meeting environmental derating limits. Mechanical criteria involve designing for durability under vibrational and thermalmechanical loading. Manufacturing criteria include meeting geometric constraints for quality control, and providing acceptable assembly conditions
A model for moisture induced corrosion failures in microelectronic packages
IEEE Transactions on Components, Hybrids, and Manufacturing Technology, 1990
ABSTRACT As integrated circuit geometries become smaller and package sizes and I/O counts increas... more ABSTRACT As integrated circuit geometries become smaller and package sizes and I/O counts increase, there is an increased potential of failures resulting from moisture ingress and corrosion. To aid in reliability prediction, design for reliability, and assessing reliability tradeoffs, a methodology for coupling the mechanisms of moisture ingress and corrosion in microelectronic packages into a first-order failure-rate model is presented. The model focuses on aluminum metallization corrosion resulting from chlorine-based contaminants, but is general enough to be applied to other cases
Circuit World, 1999
This paper presents the defects that occur during the assembly and manufacturing of solder joints... more This paper presents the defects that occur during the assembly and manufacturing of solder joints in single‐sided insertion‐mount printed wiring boards (PWBs). Each type of defect is discussed, with particular focus on how these defects are related to solderability issues, the mechanisms of failure due to defect‐induced failure accelerators, and the effect of the defect on solder joint reliability.
MilSpecs - To Be Or Not To Be
IEEE Transactions on Reliability, 1996
ABSTRACT First Page of the Article
Proceedings of 16th IEEE/CPMT International Electronic Manufacturing Technology Symposium
This report summarizes the status of electronic manufacturing and packaging technology in JTEC/WTEC
Reliability and failure analysis of Lithium Ion batteries for electronic systems
2012 13th International Conference on Electronic Packaging Technology & High Density Packaging, 2012
ABSTRACT This paper presents an investigation into the reliability and physical degradation mecha... more ABSTRACT This paper presents an investigation into the reliability and physical degradation mechanisms associated with the loss of battery performance. Cells from two different manufactures underwent cycle life testing until failure (defined as a 20% decrease in nominal capacity). Designated samples from each battery type were subjected to one of two different discharge methods, one at a constant discharge rate of 1C and the other at a constant discharge rate of 0.5C. A third group of batteries were collected and examined after undergoing catastrophic failure in field applications. The tape pull test (to test adhesion/cohesion of electrode material to current collectors) is introduced for the first time in battery literature. Other analysis techniques such as x-ray imaging and environmental scanning electron microscopy were used to investigate the structural and chemical degradation of all the samples. Statistical analysis was performed on the cycle life data to evaluate battery reliability.
Effects of Re-finishing of Terminations by Solder-Dipping on Plastic Quad Flatpack Electronic Parts
2005 7th Electronic Packaging Technology Conference
Tin whiskering is a concern with high tin finishes on electronic part terminations. Solder-dippin... more Tin whiskering is a concern with high tin finishes on electronic part terminations. Solder-dipping is being used as a method for replacing the original finish with eutectic tin-lead solder, as a tin whisker risk mitigation method. The solder-dipping process however, may expose the electronic parts to additional risks due to the the finish quality and thermal shock produced by the
Predicting the Reliability of Electronic Products
2007 8th International Conference on Electronic Packaging Technology, 2007
Reliability is the ability of a product or system to perform as intended (i.e., without failure a... more Reliability is the ability of a product or system to perform as intended (i.e., without failure and within specified performance limits) for a specified time, in its life-cycle environment. Commonly-used electronics reliability prediction methods (e.g. Mil-HDBK-217, 217-PLUS, PRISM, Telcordia, FIDES) based on handbook methods have been shown to be misleading and provide erroneous life predictions, a fact that led the U. S. military to abandon their electronics reliability prediction methods. The use of stress and damage models permits a far superior accounting of the reliability and the physics-of-failure, however sufficient knowledge of the actual operating and environmental application conditions of the product are still required. This paper presents a physics-of-failure based prognostics and health management approach for effective reliability prediction. The procedure includes failure modes, mechanisms, and effects analysis, data reduction and feature extraction from the life cycle loads, damage accumulation, and assessment of uncertainty.
2008 International Conference on Electronic Packaging Technology & High Density Packaging, 2008
The aim of qualification is to verify whether a product meets or exceeds the reliability and qual... more The aim of qualification is to verify whether a product meets or exceeds the reliability and quality requirements of its intended application. Qualification plays an important role in the process of product development. It can be classified by its specific purpose at different stages of the product development process. In this paper, a new methodology of product qualification is proposed based on physics-of-failure. This methodology consists of: product configuration and material information collection; application requirement information collection; strength limits and margins; failure modes, mechanisms and effects analysis; definition of qualification requirements; qualification test planning; testing; failure analysis and verification; and quality and reliability assessment. This approach to qualification ensures that it successfully addresses the failure mechanisms applicable to the product's specific design, manufacture, and application conditions.
Handbook of Performability Engineering
Miniaturization of electronics, reduction of time to market and new functionalities in the curren... more Miniaturization of electronics, reduction of time to market and new functionalities in the current context of autonomous driving, electrification and connectivity, are bringing new reliability challenges. Prognostics and Health Management (PHM) can be used effectively to address some of the key challenges, in particular new challenges associated with the transfer of consumer electronics to automotive industry. The concept of PHM is not new, but its application to electronic systems is relatively new. It is expected that the PHM demand for electronic systems would continuously increase as autonomous driving is being realized. This paper attempts to summarize the recent studies in the system-level PHM of electronic systems. Condition monitoring (CM) techniques and prognostics methods used for the PHM of electronic systems are reviewed first. Various implementation examples are followed using different system classifications. The findings from this review is expected to offer a technical summary of accomplishments and challenges during the course of applying PHM for electronic systems, and to identify future research tasks to be performed to make the PHM a more viable tool for reliability assessment of electronic systems.
IEEE Transactions on Device and Materials Reliability, 2012
High-power white light-emitting diodes (HPWLEDs) have attracted much attention in the lighting ma... more High-power white light-emitting diodes (HPWLEDs) have attracted much attention in the lighting market. However, as one of the highly reliable electronic products which may be not likely to fail under the traditional life test or even accelerated life test, HPWLED's lifetime is difficult to estimate by using traditional reliability assessment techniques. In this paper, the degradation-data-driven method (DDDM), which is based on the general degradation path model, was used to predict the reliability of HPWLED through analyzing the lumen maintenance data collected from the IES LM-80-08 lumen maintenance test standard. The final predicted results showed that much more reliability information (e.g., mean time to failure, confidence interval, reliability function, and so on) and more accurate prediction results could be obtained by DDDM including the approximation method, the analytical method, and the two-stage method compared to the IES TM-21-11 lumen lifetime estimation method. Among all these three methods, the two-stage method produced the highest prediction accuracy.
Measurements based on DC resistance have traditionally been used to monitor the reliability of el... more Measurements based on DC resistance have traditionally been used to monitor the reliability of electronic products. Unfortunately, DC resistance is not useful for detecting intermediate stages between a short and an open, such as a partially degraded interconnect. Under cyclic loading conditions, interconnect degradation is caused by fatigue cracking, which often initiates at the surface where the strain range is maximized. At high operating frequencies, signal propagation is concentrated at the circumferential region of an interconnect due to the skin effect. Therefore, RF impedance analysis offers a more sensitive means of detecting interconnect degradation than DC resistance. The skin effect also has implications for the reliability of electronics used in applications such as radar and telecommunications. The use of higher frequencies will make these circuits increasingly susceptible to performance degradation as a result of small cracks or deformation that would go unnoticed in ...
Journal of Intelligent Material Systems and Structures, 2011
This paper presents the application of model-based and data-driven approaches for prognostics of ... more This paper presents the application of model-based and data-driven approaches for prognostics of failures in embedded planar capacitors. An embedded planar capacitor is a thin laminate that serves both as a power/ground plane and as a parallel plate capacitor in a multilayered printed wiring board. These capacitors have gained importance with an increase in the operating frequency and a decrease in the supply voltage in electronic circuits since they can enable miniaturization of electronic circuits as well as improved electrical performance. In next generation electronic circuits, embedded planar capacitors will be crucial in communication, automotive, military, medical, and space applications. The capacitor laminate used in this study consisted of an epoxy-barium titanate nanocomposite dielectric sandwiched between Cu layers. Three electrical parameters, capacitance, dissipation factor, and insulation resistance, were monitored in situ during testing under elevated temperature and...
Popcorning in PBGA Packages During IR Reflow Soldering
Microelectronics International, 1997
Plastic ball grid arrays (PBGAs) have been gaining increasing industry acceptance as potentially ... more Plastic ball grid arrays (PBGAs) have been gaining increasing industry acceptance as potentially the lowest cost packages for high pin count applications. The main factors for their success include the inherent low cost of plastic packages, the high yields achievable with existing assembly equipment, the density advantages of an area array and, in many cases, superior electrical performance. The reliability of these packages with respect to solder joint fatigue has been extensively studied; however, little has been published on their reliability with respect to moisture‐related failure mechanisms during assembly, such as popcorning. In this study, two types of plastic ball grid array packages, a 225‐lead full matrix array and a 256‐lead perimeter array, which were preconditioned by baking at 125°C for 24 hours followed by exposure to 85°C and 30% relative humidity for 168 hours, were then subjected to three passes of simulated infra‐red reflow at 1°C/s and 0.67°C/s. Subsequent exami...
Accelerated testing and finite element analysis of PBGA under multiple environmental loadings
To investigate the long term reliability of plastic ball grid array (PBGA) packages in aerospace ... more To investigate the long term reliability of plastic ball grid array (PBGA) packages in aerospace applications, accelerated tests were conducted to non-underfilled and underfilled packages under multiple environmental loadings at board level. This paper discusses the test results and the underfill effect on solder joint reliability. Failure modes and sites were identified through failure analysis on test samples. To better understand the thermomechanical behavior of PBGAs under cyclic thermal loading environments, three dimensional FEA models for non-underfilled and underfilled packages were also developed and used to predict the time to failure.
Application of FPGA units in combined temperature cycle and vibration reliability tests of lead-free interconnections
2008 2nd Electronics Systemintegration Technology Conference, 2008
ABSTRACT According to the European Directive 2002/95/EC RoHS solders that contain lead have to be... more ABSTRACT According to the European Directive 2002/95/EC RoHS solders that contain lead have to be replaced with lead-free equivalents. Replacing well-known materials with new materials not only force technological adaptations but also force necessity of reliability investigations, especially new failure modes. In case of lead-free solders, the main problem is reduction of solder joint strength. Lower strength of lead- free solder joint in comparison with SnPb is the result of defects that occur in the joint structure. Because of local defects, the joints are much more sensitive for stresses, Stress inducted within the area of solder joint can lead to joint fractures. Despite the crack occurrence, the solder joint can still conduct electrically. Nevertheless cracked joint should be treated as failed because it does not fulfill its constructional function. Such failures can be difficult to detect in static conditions, but can be easy detected, when the tested joint is subjected to vibrations. During vibrations short opens of the joint can occur. Additional high temperature or temperature cycles loadings can make detection easier by acceleration of crack occurrence. To detect short opens of solder joints subjected to vibrations, continuous fast measurements of resistance changes during the test are required. Within the article, the essence of fast multi-channel measurements and the construction of dedicated data storage system will be described. As a summary expected results of measurements will be shortly presented.
Rolling element bearing fault detection: Combining energy operator demodulation and wavelet packet transform
2011 Prognostics and System Health Managment Confernece, 2011
Abstract Rolling element bearing vibration signal is a modulated signal, and the existence of mod... more Abstract Rolling element bearing vibration signal is a modulated signal, and the existence of modulation increases the difficulty in bearing fault detection. Hilbert transform has been widely used in signal demodulation. However, the endpoint effect often makes the result unsatisfactory. Further, bearing vibration signals are usually polluted by various noises at low frequency, and the analysis of high frequency can be more effective for bearing fault feature extraction. This paper proposes an improved method that combines the energy ...
2011 Prognostics and System Health Managment Confernece, 2011
The use of cooling fans is a low-cost solution for thermal management in electronic products. Coo... more The use of cooling fans is a low-cost solution for thermal management in electronic products. Cooling fans are used to create designed airflow to cool down the host system. Since many failures in the field can be traced back to thermally related issues in electronic products, the reliability of cooling fans is a critical part of the overall reliability of thermal management systems in electronic products. When cooling fans fail to work at the designed operating point, the host system will undergo overheating, which will degrade its performance and lead to intermittent failures and catastrophic failures. There is growing interest in the prognostics and health management (PHM) of cooling fans in electronic products. This paper works on the implementation of failure modes, mechanisms and effects analysis (FMMEA) of cooling fans in electronic products, and discusses three situations in which cooling fans can fail to provide the designed airflow to cool down their host systems. An overview of the cooling fan bearing is provided, and bearing reliability issues are also reported. Finally, the prioritization of potential failure mechanisms was performed with the estimation of risk priority numbers based on past experience and engineering judgment.