Thermal analysis of isothermal solidification kinetics duirng transient liquid-phase sintering

Abstract

A technique for experimentally measuring the kinetics of isothermal solidification during transient liquid-phase sintering (TLPS) has been successfully developed using differential scanning calorimetry (DSC). Comparison of these data with a model based on diffusion of Sn solute into an array of spherical Pb particles reveals very good agreement between predicted and measured solidification rates. The DSC technique and the solid-state diffusion model represent valuable tools in investigating the parameters that control TLPS, such as powder size, solder composition, process temperature, and heating rate.

High-temperature variable melting point Sn-Sb lead-free solder pastes using transient liquid-phase powder processing

“…The above results clearly indicate that significant alloying between the pure Sn and Sb powders prior to The DSC experiments previously designed for measuring isothermal solidification in Pb-Sn and Sn-Bi eutectic systems 6 were employed for this purpose and can be described with reference to Fig. 8.…”

“…2,3,5 When the TLP technology is applied to solder pastes, it can offer a number of advantages including the following: (1) a reduction in the solder temperature required to form a dense solder joint, (2) solder joint freezing at the solder temperature by diffusional (or isothermal) solidification, (3) variable melting point behavior allowing stepwise soldering, and (4) increased microstructural homogeneity by avoiding the formation of nonequilibrium phases that would normally form due to solidification upon cooling. [5][6][7][8] With the adoption of lead-free solders, such as SnAg-Cu in the microelectronics industry, comes the necessity to increase the solder reflow temperature used in surface mount technology (SMT). 9 Previous work on lead-free TLP solder pastes has focused on formulations that melt in the range of a conventional lead-based reflow process (i.e., peak temperatures of ϳ215-235°C).…”

“…6,7,[10][11][12][13] However, the primary objective of current investigations to develop a VMP effect distinguishes it from conventional TLP sintering. For example, TLP sintering is primarily a solid-state process where only a small volume fraction (i.e., ϳ1-5 vol.%) of liquid is used to aid in sintering.…”

Quantitative Thermal Analysis of Transient Liquid-Phase-Sintered Cu-Ni Powders

“…TRANSIENT liquid phase (TLP) processing has received considerable interest in a wide range of applications, including lower-temperature soldering in the microelectronics industry, [1][2][3][4][5][6][7] high-temperature brazing using traditional and wide-gap transient liquid phase bonding (TLPB) [8,9] and transient or supersolidus liquid phase sintering (TLPS/SLPS) of bulk materials as well as of brazes. [10][11][12][13][14] In TLPS, the transient liquid that forms during sintering, aids in rapid densification of the powder compact.…”

A study of transient liquid-phase bonding of Ag-Cu using differential scanning calorimetry

“…[19] This can be applied to TLP bonding in binary alloy systems to characterize the kinetics of isothermal solidification. In previous relevant work, Corbin and Lucier [20] have successfully used the DSC to measure process kinetics of the TLP sintering process; however, it has been shown that geometrical differences in the TLP bonding process profoundly affect the DSC results and this requires additional interpretation. [19] Venkatraman et al [21] studied the kinetics of low-temperature TLP solidification in electroplated Au-Sn layers on Cu using DSC, but the thin width of the base metal in their study does not support the semi-infinite thickness assumption made in the analytical models.…”