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Decapsulation is a failure analysis technique often used to expose the die and first-level interconnects such as wirebonds by dissolving the surrounding epoxy molding compound (EMC). The wet decapsulation technique, which uses fuming acids, works very well for traditional gold (Au) wirebonds. On the other hand, its latest alternative, copper (Cu) wirebond, reacts with the nitric acid vigorously and...
Consistent and wide-ranging material property data are needed for microelectronics encapsulants for the determination of mechanical design, reliability assessment, and process optimization of electronic packages. Since, the vast majority of contemporary underfills used are epoxy based, they have the propensity to absorb moisture, which can lead to undesirable reductions in their mechanical and adhesion...
The migration of high-reliability applications requiring sustained operation in harsh environments needs a better understanding of the acceleration factors under the stresses of operation. Prolonged exposure of the copper wire to elevated temperatures results in growth of excessive intermetallics and degradation of the interface. Behavior of Copper wirebond under high current-temperature conditions...
Emergence of flexible electronics technologies has made tractable the ability to develop solutions for integration of electronics for biometric sensing into wearable fabrics. In wearable applications, electronics may be subjected to stresses of daily motion in addition to exposure to human body temperature, and ambient environments. Existing test standards and protocols are geared towards the assessment...
Electronic fuze assemblies may be exposed to harsh environments during prolonged storage, transport and deployment. Under exposure to storage-transport environmental loads including mechanical shock, temperature, vibration and humidity the fuze assemblies may sustain damage without any surface signs of visible degradation. Further, the operational environment requires survivability under high-g loads...
Finite Element simulations are often used to study the reliability of solder joints subjected to thermal cycling. Packaging configurations are becoming more complex to accommodate better functionality and performance. Increased complexity leads to several challenges for FE models including difficulties modeling thin layers and interfaces, as well as keeping the total numbers of nodes and elements...
Electronics in automotive applications may be used for a number of safety critical systems including lane-departure warning, collision avoidance, drive assist systems, and adaptive cruise control. Furthermore, electronics in fully-electric vehicles may be used for power generation and management. Automotive electronics may be mounted on engine or on transmission or in the base of the automobile and...
Transient dynamic loads in addition to prolonged periods of high temperature exposure are a part of number of high profile applications with high reliability needs. Examples include - electronics in automotive applications may be mounted under the hood or in the trunk of the car resulting in prolonged periods of high temperature exposure followed by operation under vibration while at environmental...
In this work, we have used nanoindentation methods to explore the creep behavior, and aging effects of SAC305 solder joints at several elevated testing temperatures from 25 to 125 oC. A special high temperature stage and test protocol was used within the nanoindentation system to carefully control the testing temperature, and make the measurements insensitive to thermal drift problems. Solder joints...
In this investigation, Scanning Electron Microscopy (SEM) and Scanning Probe Microscopy (SPM) have been utilized to examine aging induced microstructural changes occurring within lead free solders. Unlike many prior studies, fixed regions in the solder joint cross-sections were monitored throughout the aging process, rather than examining different samples and/or different regions after the various...
Due to growing environmental concerns, lead-free solder materials are being widely used in electronic assemblies. The Anand viscoplastic constitutive model is frequently used to represent mechanical behavior of lead-free solder materials in finite element simulations. However, prior experimental results have demonstrated that properties of lead-free solder materials degrade over time when exposed...
Solder joints in electronic packages are frequently exposed to thermal cycling. Such exposures can occur in real life applications as well as in accelerated thermal cycling tests used for the fatigue behavior characterization. Due to the CTE mismatches of the assembly materials, cyclic temperature leads the solder joints to be subjected to cyclic (tensile/compressive) mechanical loading. On the other...
Copper (Cu) wire bonding, which is a newer alternative to Gold (Au) wire bonding, gets affected greatly by the variety of operating conditions. Selection of different materials, such as epoxy molding compound (EMC) used in the molding process plays key role in defining lifetime for wirebond system. Higher ionic contamination adversely affects the reliability of Cu wirebonds. Interaction of the EMCs...
Flexible electronics provide new design options not afforded by rigid electronics in a variety of applications including wearable electronics, robotics and automotive systems. However, the processes for the manufacturing of complex electronic assemblies using fine-pitch components are not as well developed as those for rigid electronics. The lack of structural rigidity of flexible printed circuit...
Electronics components in automotive, oil-exploration industries, military applications may be exposed to high temperature and high strain rates when subjected to shock and vibration. In harsh environment applications, electronic products may experience strain rates of 1–100 per sec and environmental temperatures up to 200°C. There is need of material data for leadfree solder alloys at high strain-rates...
Electronic devices used in higher temperatures environments such as well logging in the oil and natural gas industries, under hood automotive applications, military applications may be exposed to very high temperatures around 200°C and high strain rates. Previously, lead based solder alloys have been used in such applications but due to health concern, use of lead-free solder alloys (SAC) has been...
When exposed to a temperature changing environment, solder joints in electronic assemblies are subjected to cyclic mechanical loading due to the mismatches in coefficients of thermal expansion (CTE) of different assembly materials. Eventually, the cyclic loading results in fatigue failure of solder joints, which is one of the common failure modes in electronic packaging. Aging leads to solder microstructure...
Small form factor of the latest electronics has significantly increased the current densities in the interconnects. Under high temperature operating conditions, these interconnects fail prematurely due to electromigration phenomenon as well as Joule heating. Electromigration (EM) is a mass transport of a material due to the momentum transfer between conducting electrons and atoms. High current densities...
The effect of aging on mechanical properties of SAC 305 at low strain rate has been investigated. For high strain rate constitutive mechanical behavior, a number of researchers relied on Split Hopkinson Pressure bar and the strain rate range is from 500/s to 3000/s. However, for typical drop and shock, the strain rate range is from 1/s to 100/s. There is a general scarcity of data for solder materials...
When exposed to a temperature changing environment, solder joints in electronic assemblies are subjected to cyclic thermal-mechanical loading due to the mismatches in coefficients of thermal expansion (CTE) of the different assembly materials. Eventually, the cyclic loading can result in fatigue failure of solder joints, which is one of the common failure modes in electronic packaging. While it has...
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