The Experts below are selected from a list of 1446 Experts worldwide ranked by ideXlab platform
Weizhi Wang - One of the best experts on this subject based on the ideXlab platform.
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Atomic Flux measurement by diode laser based Atomic absorption spectroscopy
Journal of Vacuum Science and Technology, 1999Co-Authors: Weizhi Wang, R H Hammond, M M Fejer, M R BeasleyAbstract:Diode-laser-based Atomic absorption (AA) sensors have been developed for direct measurement of Atomic Flux, based on both Atomic density and velocity information, which is important for in situ monitoring and control of physical vapor deposition processes. Laser beam schemes based on the Doppler shift measurement have been designed for measuring the velocity component normal to the surface of a substrate. Experimental results on electron-beam evaporated barium and yttrium, which are components in YBCO superconductor, demonstrate measurements of true Flux instead of simple density in the deposition processes. The Flux measurement was confirmed at different pressures showing true Flux measurement independent of background pressure. A model-independent Flux measurement was achieved by using a cross-beam scheme. In addition, the AA sensor was also used for diagnosing and helping better understand the deposition physics such as sticking coefficient, velocity of the evaporated atoms, and the oxidation of the el...
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generation of Atomic nitrogen Flux monitoring by an Atomic absorption detection system at 120 nm
Journal of Vacuum Science and Technology, 1999Co-Authors: Weizhi Wang, R H Hammond, S B Arnason, M R BeasleyAbstract:We have demonstrated a lamp-based Atomic absorption detection system at 120 nm for monitoring Atomic nitrogen generation in microwave discharge. Atomic nitrogen Flux and dissociation ratio were evaluated by the Atomic absorption. Delivery of Atomic nitrogen with a quartz tube was investigated. By suppressing the recombination of the Atomic nitrogen with the Teflon insert, the delivered Atomic nitrogen Flux was enhanced by a factor of 3–10. At a microwave power of 300 W, an Atomic Flux of 5×1016 cm−2 s−1, sufficient for growth of nitride thin films, was achieved. A model of recombination was used for explaining the experimental results, a maximum dissociation ratio of ∼2% at the plasma region was estimated based on the measured Atomic nitrogen densities.
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direct Atomic Flux measurement of electron beam evaporated yttrium with a diode laser based Atomic absorption monitor at 668 nm
Applied Physics Letters, 1997Co-Authors: Weizhi Wang, R H Hammond, M M Fejer, S B Arnason, M R Beasley, M L BortzAbstract:A direct measurement of Atomic Flux in e-beam evaporated yttrium has been demonstrated with a diode-laser-based Atomic absorption (AA) monitor at 668 nm. Atomic number density and velocity were measured through absorption and Doppler shift measurements to provide the Atomic Flux. The AA-based deposition rates were compared with independent quartz crystal monitors showing agreement between the two methods.
M L Bortz - One of the best experts on this subject based on the ideXlab platform.
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direct Atomic Flux measurement of electron beam evaporated yttrium with a diode laser based Atomic absorption monitor at 668 nm
Applied Physics Letters, 1997Co-Authors: Weizhi Wang, R H Hammond, M M Fejer, S B Arnason, M R Beasley, M L BortzAbstract:A direct measurement of Atomic Flux in e-beam evaporated yttrium has been demonstrated with a diode-laser-based Atomic absorption (AA) monitor at 668 nm. Atomic number density and velocity were measured through absorption and Doppler shift measurements to provide the Atomic Flux. The AA-based deposition rates were compared with independent quartz crystal monitors showing agreement between the two methods.
M R Beasley - One of the best experts on this subject based on the ideXlab platform.
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Atomic Flux measurement by diode laser based Atomic absorption spectroscopy
Journal of Vacuum Science and Technology, 1999Co-Authors: Weizhi Wang, R H Hammond, M M Fejer, M R BeasleyAbstract:Diode-laser-based Atomic absorption (AA) sensors have been developed for direct measurement of Atomic Flux, based on both Atomic density and velocity information, which is important for in situ monitoring and control of physical vapor deposition processes. Laser beam schemes based on the Doppler shift measurement have been designed for measuring the velocity component normal to the surface of a substrate. Experimental results on electron-beam evaporated barium and yttrium, which are components in YBCO superconductor, demonstrate measurements of true Flux instead of simple density in the deposition processes. The Flux measurement was confirmed at different pressures showing true Flux measurement independent of background pressure. A model-independent Flux measurement was achieved by using a cross-beam scheme. In addition, the AA sensor was also used for diagnosing and helping better understand the deposition physics such as sticking coefficient, velocity of the evaporated atoms, and the oxidation of the el...
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generation of Atomic nitrogen Flux monitoring by an Atomic absorption detection system at 120 nm
Journal of Vacuum Science and Technology, 1999Co-Authors: Weizhi Wang, R H Hammond, S B Arnason, M R BeasleyAbstract:We have demonstrated a lamp-based Atomic absorption detection system at 120 nm for monitoring Atomic nitrogen generation in microwave discharge. Atomic nitrogen Flux and dissociation ratio were evaluated by the Atomic absorption. Delivery of Atomic nitrogen with a quartz tube was investigated. By suppressing the recombination of the Atomic nitrogen with the Teflon insert, the delivered Atomic nitrogen Flux was enhanced by a factor of 3–10. At a microwave power of 300 W, an Atomic Flux of 5×1016 cm−2 s−1, sufficient for growth of nitride thin films, was achieved. A model of recombination was used for explaining the experimental results, a maximum dissociation ratio of ∼2% at the plasma region was estimated based on the measured Atomic nitrogen densities.
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direct Atomic Flux measurement of electron beam evaporated yttrium with a diode laser based Atomic absorption monitor at 668 nm
Applied Physics Letters, 1997Co-Authors: Weizhi Wang, R H Hammond, M M Fejer, S B Arnason, M R Beasley, M L BortzAbstract:A direct measurement of Atomic Flux in e-beam evaporated yttrium has been demonstrated with a diode-laser-based Atomic absorption (AA) monitor at 668 nm. Atomic number density and velocity were measured through absorption and Doppler shift measurements to provide the Atomic Flux. The AA-based deposition rates were compared with independent quartz crystal monitors showing agreement between the two methods.
Yuanxiang Zhang - One of the best experts on this subject based on the ideXlab platform.
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Modeling Effect of Grain Orientation on Degradation in Tin-Based Solder: I. Current-Driven Diffusion
IEEE Transactions on Components Packaging and Manufacturing Technology, 2019Co-Authors: Yuanxiang Zhang, Jiamin Ni, Antoinette M. ManiattyAbstract:In this and subsequent papers, we consider the effects of the microstructure, in particular grain orientations, and the associated anisotropy of Sn grains on electromigration-induced degradation in lead-free solder bumps. This paper investigates the effect of the anisotropy of Sn grains on current-driven self-diffusion and the resulting Atomic Flux divergence that is associated with material depletion at the cathode side of the bump and ultimately failure. Finite-element thermoelectric simulations of a section of a chip scale package and a refined submodel are carried out assuming single-crystal and bi-crystal solder bumps. Anisotropic material properties of $\beta $ -Sn are used in the simulations. By varying crystal orientation of the solder bumps, the effect of grain orientation on the current density, temperature, and Atomic Flux divergence is studied and discussed. In the future papers, we will consider the coupled mechanical response including stress-driven diffusion.
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Modeling Effect of Grain Orientation on Degradation in Tin-Based Solder: I. Current-Driven Diffusion
IEEE Transactions on Components Packaging and Manufacturing Technology, 2019Co-Authors: Yuanxiang Zhang, Jiamin Ni, Antoinette M. ManiattyAbstract:In this and subsequent papers, we consider the effects of the microstructure, in particular grain orientations, and the associated anisotropy of Sn grains on electromigration-induced degradation in lead-free solder bumps. This paper investigates the effect of the anisotropy of Sn grains on current-driven self-diffusion and the resulting Atomic Flux divergence that is associated with material depletion at the cathode side of the bump and ultimately failure. Finite-element thermoelectric simulations of a section of a chip scale package and a refined submodel are carried out assuming single-crystal and bi-crystal solder bumps. Anisotropic material properties of β-Sn are used in the simulations. By varying crystal orientation of the solder bumps, the effect of grain orientation on the current density, temperature, and Atomic Flux divergence is studied and discussed. In the future papers, we will consider the coupled mechanical response including stress-driven diffusion.
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Finite element modeling on electromigration of TSV interconnect in 3D package
2018 IEEE 20th Electronics Packaging Technology Conference (EPTC), 2018Co-Authors: Yuanxiang Zhang, Sijia Yu, Deqi Su, Zhipeng ShenAbstract:Through silicon vias (TSV) are very important components in 3D integrated circuits, because they are responsible for the vertical connection inside the package. In this paper, a finite element model on electromigration is established to investigate the mass diffusion phenomenon for TSV interconnect in 3D stacked structure. Electric-thermo-mechanical coupled analysis is carried out to obtain the current density, temperature and stress distribution of TSV structure under high current density load. Atomic Flux divergence is calculated By ANSYS APDL to evaluate electromigration failure of TSV structure. The different migration effects in the electromigration modeling of the TSV structure is also discussed.
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The effect of Atomic density gradient in electromigration
International Journal of Materials and Structural Integrity, 2012Co-Authors: Yuanxiang Zhang, Lihua LiangAbstract:This paper studies the electromigration (EM) failure of interconnect structure and solder joint in a wafer level chip scale package (WL-CSP) based on Atomic Flux divergence (AFD) method. The impact of Atomic density gradient (ADG) on the divergence of the Atomic Fluxes is investigated. The simulation results show that the traditional AFD method, which neglects the effect of Atomic density gradient, can result in significant errors in predicting solder joint failures in a WL-CSP; while the AFD method with the consideration of the Atomic density gradient has shown more reasonable results.
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A New Algorithm for EM Analysis Considering Multiple Driving Forces Mechanism
2008 10th Electronics Packaging Technology Conference, 2008Co-Authors: Lihua Liang, Yuanxiang Zhang, Xuefan ChenAbstract:This paper studies the numerical simulation method for electromigration void incubation and afterwards void propagation based on commercial software ANSYS Multi-physics and FORTRAN code. The electronic migration formulation considering the effects of the electron wind force, stress gradients, temperature gradients, as well as the Atomic concentration gradient has been developed for the electromigration failure mechanisms. Due to introducing the Atomic concentration gradient driving force in Atomic Flux formulation, the conventional Atomic Flux divergence method cannot be used in the new EM algorithm. Therefore the corresponding EM Atomic concentration redistribution method is proposed using FORTRAN code. A link between ANSYS and FORTRAN code is developed to transfer the data. The Atomic concentration information is imported into ANSYS Multi-physics and then the Atomic concentration distribution of the studied structure can be gotten. Finally, the comparison of voids generation through numerical example of a SWEAT structure with the measurement result is studied and discussed.
R H Hammond - One of the best experts on this subject based on the ideXlab platform.
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Atomic Flux measurement by diode laser based Atomic absorption spectroscopy
Journal of Vacuum Science and Technology, 1999Co-Authors: Weizhi Wang, R H Hammond, M M Fejer, M R BeasleyAbstract:Diode-laser-based Atomic absorption (AA) sensors have been developed for direct measurement of Atomic Flux, based on both Atomic density and velocity information, which is important for in situ monitoring and control of physical vapor deposition processes. Laser beam schemes based on the Doppler shift measurement have been designed for measuring the velocity component normal to the surface of a substrate. Experimental results on electron-beam evaporated barium and yttrium, which are components in YBCO superconductor, demonstrate measurements of true Flux instead of simple density in the deposition processes. The Flux measurement was confirmed at different pressures showing true Flux measurement independent of background pressure. A model-independent Flux measurement was achieved by using a cross-beam scheme. In addition, the AA sensor was also used for diagnosing and helping better understand the deposition physics such as sticking coefficient, velocity of the evaporated atoms, and the oxidation of the el...
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generation of Atomic nitrogen Flux monitoring by an Atomic absorption detection system at 120 nm
Journal of Vacuum Science and Technology, 1999Co-Authors: Weizhi Wang, R H Hammond, S B Arnason, M R BeasleyAbstract:We have demonstrated a lamp-based Atomic absorption detection system at 120 nm for monitoring Atomic nitrogen generation in microwave discharge. Atomic nitrogen Flux and dissociation ratio were evaluated by the Atomic absorption. Delivery of Atomic nitrogen with a quartz tube was investigated. By suppressing the recombination of the Atomic nitrogen with the Teflon insert, the delivered Atomic nitrogen Flux was enhanced by a factor of 3–10. At a microwave power of 300 W, an Atomic Flux of 5×1016 cm−2 s−1, sufficient for growth of nitride thin films, was achieved. A model of recombination was used for explaining the experimental results, a maximum dissociation ratio of ∼2% at the plasma region was estimated based on the measured Atomic nitrogen densities.
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direct Atomic Flux measurement of electron beam evaporated yttrium with a diode laser based Atomic absorption monitor at 668 nm
Applied Physics Letters, 1997Co-Authors: Weizhi Wang, R H Hammond, M M Fejer, S B Arnason, M R Beasley, M L BortzAbstract:A direct measurement of Atomic Flux in e-beam evaporated yttrium has been demonstrated with a diode-laser-based Atomic absorption (AA) monitor at 668 nm. Atomic number density and velocity were measured through absorption and Doppler shift measurements to provide the Atomic Flux. The AA-based deposition rates were compared with independent quartz crystal monitors showing agreement between the two methods.
