Wetting Transition of Grain Boundaries in Tin–Rich Indium-Based Alloys and Its Influence on Electrical Properties

Abstract

The microstructural evolution of tin-rich indium-based alloys after the grain boundary wetting phase transition in the (liquid + ) twophase region of the tin-indium phase diagram and its influence on the electrical conductivity were investigated. Five tin-indium alloys, Sn In 30 alloys had different amounts of completely wetted grain boundaries after annealing. The XRD results show the changes in phases that underwent the eutectic transformation during quenching from various annealing temperatures. The electrical conductivity of annealed tinindium specimens with various microstructures was measured. It increased with both annealing temperature and tin content.

Effect of electric current pulses on solidification of immiscible alloys

“…These results indicate that ECPs promote the Bi-10%Cu-10%Sn alloy to form a well-dispersed microstructure. [10][11][12]. Fig.…”

Direct Macroscopic Modeling of Grain Structure and Macrosegregation with a Cellular Automaton–Finite Element Model

“…For cubic crystalline materials, the grain envelope is characterized by a quadrilateral shape in 2D case and an octahedral shape in 3D case. Only the nucleation and growth of the primary solid phase is considered, and the grain boundary wetting [24,25] is ignored. As shown in Figure 1b, the CA and FE grids are completely superimposed.…”

“…Since the temperature, composition, and liquid velocity change with time and space during the solidification of alloys, the dendrite tip growth kinetics are required to give a dendrite tip growth velocity based on the local temperature, composition, and liquid velocity of each growing CA cell. In order to ensure the reliability of the present CAFE model, the modified dendrite tip growth kinetics defined by Equations (15)- (24) are first validated with respect to Sn-Pb alloys with fluid flow. Figures 3 and 4 show the comparisons of the dendrite tip growth velocity of Sn-Pb alloys calculated by present correlation and the correlation given by Ananth and Gill [32], which yield exact solutions based on several flow approximations.…”

Fine Microstructured In–Sn–Bi Solder for Adhesion on a Flexible PET Substrate: Its Effect on Superplasticity and Toughness

“…In flexible microelectronics packaging, there has been an increase in demand for more advanced solders with high electrical conductivity, a low melting temperature, and high ductility and toughness, which allows them to perform well in extreme environments such as those found in miniaturized microelectronic components, in which the pitch distance drops to the submicron level and there is an increasing pin count to meet high microchip loads. − In this respect, the eutectic composition of In–Sn solder, which has an intrinsically low electrical resistivity of (10.0–15.0) × 10 –6 Ω cm due to the presence of In (8.4 × 10 –6 Ω cm) and Sn (11.5 × 10 –6 Ω cm), facilitates the rapid transfer of electronic/electrical signals between microchips and conductive patterns on a substrate. , Furthermore, the In-based solder also has a low melting point of 118 °C, and on the basis of the metallurgy principle with regard to the movement toward a more eutectic temperature (usually a lower temperature), the incorporation of a certain additive can decrease the melting temperature even further, which would make it possible to reflow the solder on a plastic substrate with low thermal resistance. ,, For example, poly­(ethylene terephthalate) (PET) substrates exhibit considerable thermal damage after reflowing at temperatures even slightly higher than 110 °C, which severely limits the use of conventional solders due to the need to reflow them at the much higher temperature of 250 °C. ,,− Such high temperatures during the reflow process can also damage other heat-sensitive components, including conductive polymers, organic light-emitting diodes, polymer light-emitting diodes, and so on, and simultaneously thermal stress and strain appear in the solder. ,− Given such features, either soldering (completed melting process without residual thermal stress and strain caused by the temperature gradient) at a low melting temperature of less than 110 °C or utilizing a plastic substrate with high thermal resistance can be applied to solve these problems. ,,− , In our experiments, the addition of a small amount of Bi to the solder enabled to lower the melting point to below 110 °C, a temperature at which the PET substrate does not thermally decompose. ,,− As another solution, high-thermal resistance films, such as polyimide, polycarbonate, and so on, which are thermally resistant up to 250 °C can be used, although such substrates are several hundred times more expensive than PET and much less flexible and transparent, which is beyond the scope of this study. ,,,− Also...…”

“…1−6 In this respect, the eutectic composition of In−Sn solder, which has an intrinsically low electrical resistivity of (10.0−15.0) × 10 −6 Ω cm due to the presence of In (8.4 × 10 −6 Ω cm) and Sn (11.5 × 10 −6 Ω cm), facilitates the rapid transfer of electronic/electrical signals between microchips and conductive patterns on a substrate. 7,8 Furthermore, the In-based solder also has a low melting point of 118 °C, and on the basis of the metallurgy principle with regard to the movement toward a more eutectic temperature (usually a lower temperature), the incorporation of a certain additive can decrease the melting temperature even further, which would make it possible to reflow the solder on a plastic substrate with low thermal resistance. 1,7,9 For example, poly(ethylene terephthalate) (PET) substrates exhibit consid-erable thermal damage after reflowing at temperatures even slightly higher than 110 °C, which severely limits the use of conventional solders due to the need to reflow them at the much higher temperature of 250 °C.…”