Extreme Fast-Diffusion System: Nickel in Single-Crystal Tin

Yeh, D. C.; Huntington, H. B.

doi:10.1103/physrevlett.53.1469

Cited by 173 publications

(45 citation statements)

References 10 publications

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“…Similar attempts have also been made in the study of colloidal transport and diffusion in a 1D optical trap (optical tweezers) with either a periodic or random variation of the laser light intensity [21][22][23][24]. Understanding the effect of the external force on thermally activated kinetics is a concern of a common class of transport problem, such as particle separation by electrophoresis [25,26], electromigration of atoms on the surface of metals [27] and semiconductors [28], motion of a three-phase contact line under the influence of an unbalanced capillary force [29], control of crystal growth [30], and design of nanoscale machineries [31,32]. In biology and biophysics, force-assisted thermal activation is employed in various single-molecule stretching experiments to study the binding and folding energy landscape of biomolecules, such as DNA [33], RNA [34], nucleic acids [35], receptors and ligands [36], and proteins [37], and the adhesion between biomembranes of vesicles, capsules, and living cells [38,39].…”

Section: Introductionmentioning

confidence: 98%

Colloidal dynamics over a tilted periodic potential: Nonequilibrium steady-state distributions

Lai

Ackerson

et al. 2015

Phys. Rev. E

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We report a systematic study of the effects of the external force F on the nonequilibrium steady-state (NESS) dynamics of the diffusing particles over a tilted periodic potential, in which detailed balance is broken due to the presence of a steady particle flux. A tilted two-layer colloidal system is constructed for this study. The periodic potential is provided by the bottom-layer colloidal spheres forming a fixed crystalline pattern on a glass substrate. The corrugated surface of the bottom colloidal crystal provides a gravitational potential field for the top-layer diffusing particles. By tilting the sample at an angle θ with respect to the vertical (gravity) direction, a tangential component of the gravitational force F is applied to the diffusing particles. The measured NESS probability density function P ss (x,y) of the particles is found to deviate from the equilibrium distribution P (x,y) to a different extent, depending on the driving or distance from equilibrium. The experimental results are compared with the exact solution of the one-dimensional (1D) Smoluchowski equation and the numerical results of the 2D Smoluchowski equation. From the obtained exact solution of the 1D Smoluchowski equation, we develop an analytical method to accurately extract the 1D potential U 0 (x) from the measured P ss (x). This work demonstrates that the tilted periodic potential provides a useful platform for the study of forced barrier-crossing dynamics beyond the Arrhenius-Kramers equation.

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Section: Introductionmentioning

confidence: 98%

Colloidal dynamics over a tilted periodic potential: Nonequilibrium steady-state distributions

Lai

Ackerson

et al. 2015

Phys. Rev. E

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“…A joint containing few Sn orientations will have highly anisotropic properties because Sn has highly directional thermophysical properties [18]. For example, the coefficient of thermal expansion [19], elastic stiffness [20], diffusion coefficient of common solutes [21] and plasticity [17] are all strongly direction dependent in Sn. Furthermore, if the few Sn grains are oriented differently in each joint, then the behaviour of each joint is unique.…”

Section: Introductionmentioning

confidence: 99%

Nucleation and Growth of Tin in Pb-Free Solder Joints

Gourlay

Belyakov

et al. 2015

JOM

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The solidification of Pb-free solder joints is overviewed with a focus on the formation of the Sn grain structure and grain orientations. Three solders commonly used in electronics manufacturing, Sn-3Ag-0.5Cu, Sn-3.5Ag and Sn-0.7Cu-0.05Ni, are used as case studies to demonstrate that growth competition between primary dendrites and eutectic fronts during growth in undercooled melts is important in Pb-free solders, and that a metastable eutectic containing NiSn4 forms in Sn-3.5Ag/Ni joints. Additionally, it is shown that the substrate (metallization) has a strong influence on the nucleation and growth of tin. We identify Co, Pd and Pt substrates as having potential to control solidification and microstructure formation. In the case of Pd and Pt substrates, Sn is shown to nucleate on the PtSn4 or PdSn4 IMC reaction layer at relatively low undercooling of ~4K, even for small solder ball diameters down to <200 m. IntroductionThe transition to Pb-free electronic interconnections has been underway for more than a decade and despite the exemptions to the RoHS Directive there are few applications where Pb-free solders are not being used. At the same time, electronic packaging technologies have been advancing and there is an ongoing need to develop next-generation Pb-free solders and substrates that are better suited to smaller joints that can operate at higher temperature and that are more reliable.The most commonly used Pb-free solders are hypoeutectic or near-eutectic compositions from the Sn-Ag-Cu (SAC), Sn-Ag or Sn-Cu-Ni alloy systems. These compositions solidify with significant differences to the near-eutectic Sn-Pb solders used previously. For example, where the Sn-37Pb

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“…3 Fast diffusion, electromigration, and thermomigration caused by certain grain orientations have been widely confirmed. [4][5][6] Cu 6 Sn 5 essentially maintains a hexagonal structure, i.e., g-Cu 6 Sn 5 , during soldering reactions, 7,8 and this highly anisotropic phase appears to have a considerable influence on its growth and performance. The growth rate of the g-Cu 6 Sn 5 planes along the [0001] direction was about 28 times faster than that normal to the [0001] direction.…”

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confidence: 99%

“…The grain number of solder matrices, IMCs, and under bump metallization (UBM) in fine pitch interconnects will be small, maybe just a few grains, and so, anisotropic behaviors are expected. [3][4][5][6][7][8][9][10][11][12][13] Variation in grain orientation may lead to a wide distribution of the orientationdependent properties of microinterconnects, which may in turn lead to early failure and low reliability. 3 Fast diffusion, electromigration, and thermomigration caused by certain grain orientations have been widely confirmed.…”

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confidence: 99%

Continuous epitaxial growth of extremely strong Cu6Sn5 textures at liquid-Sn/(111)Cu interface under temperature gradient

Zhong

Zhao

Liu

et al. 2017

Applied Physics Letters

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As the diameter of solder interconnects in three-dimensional integrated circuits (3D ICs) downsizes to several microns, how to achieve a uniform microstructure with thousands of interconnects on stacking chips becomes a critical issue in 3D IC manufacturing. We report a promising way for fabricating fully intermetallic interconnects with a regular grain morphology and a strong texture feature by soldering single crystal (111) Cu/Sn/polycrystalline Cu interconnects under the temperature gradient. Continuous epitaxial growth of η-Cu6Sn5 at cold end liquid-Sn/(111)Cu interfaces has been demonstrated. The resultant η-Cu6Sn5 grains show faceted prism textures with an intersecting angle of 60° and highly preferred orientation with their ⟨112¯0⟩ directions nearly paralleling to the direction of the temperature gradient. These desirable textures are maintained even after soldering for 120 min. The results pave the way for controlling the morphology and orientation of interfacial intermetallics in 3D packaging technologies.

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Extreme Fast-Diffusion System: Nickel in Single-Crystal Tin

Cited by 173 publications

References 10 publications

Colloidal dynamics over a tilted periodic potential: Nonequilibrium steady-state distributions

Colloidal dynamics over a tilted periodic potential: Nonequilibrium steady-state distributions

Nucleation and Growth of Tin in Pb-Free Solder Joints

Continuous epitaxial growth of extremely strong Cu6Sn5 textures at liquid-Sn/(111)Cu interface under temperature gradient

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