The Experts below are selected from a list of 57 Experts worldwide ranked by ideXlab platform
Jongwoo Park - One of the best experts on this subject based on the ideXlab platform.
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Reliability of Pb-free preplated leadframe under atmosphere and accelerated aging test
IEEE Transactions on Device and Materials Reliability, 2006Co-Authors: Jongwoo Park, Young-hee Kim, Seung-woog Wang, Seung-woo Lee, Hyun-goo JeonAbstract:Atmospheric corrosion of Pb-free preplated leadframe (PPF) finish, which causes unacceptable appearance due to discoloration, has been meticulously investigated. The discoloration appears particularly on the shoulder, tip, and sidewall of the leadframe, where bare Cu is directly exposed to the given environments. Such Cu exposure is attributed to the forming and trimming process of the PPF. It is found that the geometrical feature of the ragged shear edge on the sidewall of the PPF is dependent on the condition of a cutting tool. There is a porous Ni layer on the Cu substrate. It is also found that the tarnish products consist of cuprous oxide (Cu/sub 2/O) and cuprous sulfide (Cu/sub 2/S). The depth profile reveals a thick Cu oxidation layer over cuprous sulfide, which implies that the integrity of a dual inline package assembled with the PPF is susceptible when exposed to a relatively higher humidity and sulfur-involved environments. To reproduce the atmospheric corrosion, a variety of laboratory aging tests that include the mixed flowing gas (MFG) test was used. Except the MFG test, the laboratory corrosion that yields Cu oxidation only is not identical to the atmospheric corrosion. As results, electronic devices assembled with the PPF must be sealed into a moisture-barrier bag to extend the shelf life during storage, if particularly they are exposed to relatively harsh circumstances, higher humidity in H/sub 2/S atmosphere.
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Growth kinetics of interfacial damage: epoxy coating on a generic dual inline package
IEEE Transactions on Components and Packaging Technologies, 2001Co-Authors: Jongwoo Park, D.g. Harlow, H.f. NiedAbstract:Epoxy coated dual inline packages (DIPs) consisting of 24 pins and three parallel gold metallization lines were used as test vehicles in accelerated environmental tests. The coated DIPs were subjected to 121/spl deg/C, 100% relative humidity, and unbiased conditions as a standard test condition. After each test, optical microscopy was performed to monitor the interfacial damage. Changes in the leakage current also were monitored for correlation with measured interfacial damage. The growth of interfacial damage as a function of time was observed over the entire surface area of each DTP. Each damage site on the interface was monitored in an effort to model the evolution of the geometrical features and magnitude of the damage. It was noted that a two-parameter Frechet cumulative distribution function (cdf) could be used to represent the damage growth at each time interval. Precipitate in typical damage locations also was analyzed and found to consist primarily of sodium, carbon, and oxygen. The growth kinetics of interfacial damage, including the location and magnitude of the damage, is characterized, and the dominant failure modes are identified for this type of protective coating.
Xu Wang - One of the best experts on this subject based on the ideXlab platform.
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Fatigue reliability design for metal dual inline packages under random vibration based on response surface method
Microelectronics Reliability, 2019Co-Authors: Bo Wan, Wenqiang Zhou, Xu WangAbstract:Abstract With the diversity and complexity of application environment, electronic products always work under harsh random vibration conditions. Especially for metal Dual Inline packages, the solder joints between printed circuit boards and devices in mechanical vibrations not only need to support great weights, but also require standing much stronger stresses because of the metal packaging materials. In this paper, fatigue reliability design for Metal Dual Inline packages under random vibration was conducted based on finite element analysis, physics of failure model and surface response method. The modal analysis for a prototype of the printed circuit board was carried out by both simulations and experiments. Equivalent stress distributions of the validated model under random vibration during normal working were calculated as well as that of critical solder joint under the metal Dual Inline package device. The workflows of fatigue lifecycle prediction and response surface method were established. Moreover, as a case study, fatigue reliability design for the metal Dual Inline package device in the prototype PCB was implemented to optimize the design parameters and improve the fatigue lifecycle more than ten times by the proposed method.
H.f. Nied - One of the best experts on this subject based on the ideXlab platform.
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Growth kinetics of interfacial damage: epoxy coating on a generic dual inline package
IEEE Transactions on Components and Packaging Technologies, 2001Co-Authors: Jongwoo Park, D.g. Harlow, H.f. NiedAbstract:Epoxy coated dual inline packages (DIPs) consisting of 24 pins and three parallel gold metallization lines were used as test vehicles in accelerated environmental tests. The coated DIPs were subjected to 121/spl deg/C, 100% relative humidity, and unbiased conditions as a standard test condition. After each test, optical microscopy was performed to monitor the interfacial damage. Changes in the leakage current also were monitored for correlation with measured interfacial damage. The growth of interfacial damage as a function of time was observed over the entire surface area of each DTP. Each damage site on the interface was monitored in an effort to model the evolution of the geometrical features and magnitude of the damage. It was noted that a two-parameter Frechet cumulative distribution function (cdf) could be used to represent the damage growth at each time interval. Precipitate in typical damage locations also was analyzed and found to consist primarily of sodium, carbon, and oxygen. The growth kinetics of interfacial damage, including the location and magnitude of the damage, is characterized, and the dominant failure modes are identified for this type of protective coating.
Hyun-goo Jeon - One of the best experts on this subject based on the ideXlab platform.
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Reliability of Pb-free preplated leadframe under atmosphere and accelerated aging test
IEEE Transactions on Device and Materials Reliability, 2006Co-Authors: Jongwoo Park, Young-hee Kim, Seung-woog Wang, Seung-woo Lee, Hyun-goo JeonAbstract:Atmospheric corrosion of Pb-free preplated leadframe (PPF) finish, which causes unacceptable appearance due to discoloration, has been meticulously investigated. The discoloration appears particularly on the shoulder, tip, and sidewall of the leadframe, where bare Cu is directly exposed to the given environments. Such Cu exposure is attributed to the forming and trimming process of the PPF. It is found that the geometrical feature of the ragged shear edge on the sidewall of the PPF is dependent on the condition of a cutting tool. There is a porous Ni layer on the Cu substrate. It is also found that the tarnish products consist of cuprous oxide (Cu/sub 2/O) and cuprous sulfide (Cu/sub 2/S). The depth profile reveals a thick Cu oxidation layer over cuprous sulfide, which implies that the integrity of a dual inline package assembled with the PPF is susceptible when exposed to a relatively higher humidity and sulfur-involved environments. To reproduce the atmospheric corrosion, a variety of laboratory aging tests that include the mixed flowing gas (MFG) test was used. Except the MFG test, the laboratory corrosion that yields Cu oxidation only is not identical to the atmospheric corrosion. As results, electronic devices assembled with the PPF must be sealed into a moisture-barrier bag to extend the shelf life during storage, if particularly they are exposed to relatively harsh circumstances, higher humidity in H/sub 2/S atmosphere.
Bo Wan - One of the best experts on this subject based on the ideXlab platform.
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Fatigue reliability design for metal dual inline packages under random vibration based on response surface method
Microelectronics Reliability, 2019Co-Authors: Bo Wan, Wenqiang Zhou, Xu WangAbstract:Abstract With the diversity and complexity of application environment, electronic products always work under harsh random vibration conditions. Especially for metal Dual Inline packages, the solder joints between printed circuit boards and devices in mechanical vibrations not only need to support great weights, but also require standing much stronger stresses because of the metal packaging materials. In this paper, fatigue reliability design for Metal Dual Inline packages under random vibration was conducted based on finite element analysis, physics of failure model and surface response method. The modal analysis for a prototype of the printed circuit board was carried out by both simulations and experiments. Equivalent stress distributions of the validated model under random vibration during normal working were calculated as well as that of critical solder joint under the metal Dual Inline package device. The workflows of fatigue lifecycle prediction and response surface method were established. Moreover, as a case study, fatigue reliability design for the metal Dual Inline package device in the prototype PCB was implemented to optimize the design parameters and improve the fatigue lifecycle more than ten times by the proposed method.
