Local melting and shape controlling of solder joint via induction heating

A rapid yet simple methodology to form the solder joints used in electronic packaging has been demonstrated through an induction heating system in this paper. The objective is to control the shapes of the solder joints precisely and form the hourglass-shaped solder joint using local melting phenomenon. For Sn–Ag eutectic solder bullet-shaped solder bumps and hourglass-shaped solder joints can be obtained easily within 2.3 s. The reason for the formation of hourglass-shaped solder joints has been analyzed using different morphologies of Ag3Sn intermetallic compound (IMC), and is explained by the non-uniform temperature distribution caused by a local melting phenomenon and skin effect.