In order to study the effect of different Cu/Sn ratios on the IMC-Cu interface behavior of composite micro solder joints

this article uses a combination of Transient Liquid Phase Welding and pressure

using foamed copper

pure Sn and Cu substrates as raw materials to prepare IMC-Cu composite micro solder joints.The effect of different Cu/Sn ratio on the growth behavior of composite micro solder joint IMC was studied.The results show that the ratio of Cu/Sn has a significant effect on the growth behavior of IMC in composite solder joints.As the Cu content in the solder joint increases

the growth rate of the overall thickness of the IMC increases.Reducing the Sn content in the composite micro solder joint is beneficial to the growth of Cu3Sn at the reaction interface.The time to obtain all Cu3Sn-Cu composite micro solder joints decreases with the decrease of Sn content in the solder joints.Under the same welding conditions.When the bonding time is 25 minutes

the full Cu3Sn joint is formed first when the Sn content in the composite micro solder joint is 20%

which is 20% shorter than the bonding time when the Sn content is 40%.When the Sn content is in the range of 20%-40%

with the decrease of the Sn content in the solder joints

the growth rate of Cu3Sn increases

and the time to obtain all Cu3Sn-Cu composite micro solder joints is shortened.