Controlling the distribution of porosity during transient liquid phase bonding of Sn-based solder joint

Controlling Pore Position during Transient Liquid Phase Bonding for High-temperature Soldering Processes

“…This method can be used to redistribute microvoids and avoid the agglomeration of porosities in a plane parallel to the substrate in the joint. [23,24] This finding is consistent with previous research, which shows that pores move in response to the growth of IMCs. [23,24]…”

“…[23,24] This finding is consistent with previous research, which shows that pores move in response to the growth of IMCs. [23,24]…”

“…1(c), we found that as the concentration of the Cu-Ni substrate used in a joint was changed, the location of the porosity could be shifted, [24] reflecting the differential in growth velocity of the IMC coming from each substrate and the ability of the IMC to 'push' porosity at the interface. This study demonstrated the ability to control the location of porosity in TLP joints by varying the growth rate of IMCs formed from the reaction of molten Sn-0.7Cu with different Cu-Ni substrates [24] as shown in Fig. 1 (c).…”

“…We have previously investigated these two main problems, which are summarised in Fig. 1, [15,[22][23][24] and proposed a novel production method to obtain a high-temperature joint while minimising processing times and the impact of porosity.…”

“…Fig.1The influence of substrate composition and location on IMC growth and porosity formation during TLP bonding;(a) slow growth kinetics of IMC and formation of porosity at the liquid/IMC interface in a Cu/Sn/Cu joint, (b) rapid growth kinetics of IMCs when Sn solder reacts with Cu-6Ni substrates and formation of centrally located porosity in the TLP joint,[23] (c) controlling the location of porosity in a joint formed through TLP bonding using differing substrate compositions,[24] and (d) proposed method to limit the TLP central porosity utilising a substrate with a variable concentration of Ni in Cu.…”