A study on the reliability of the chip surface solder joint

The solder joint reliability of IGBT chip surface interconnection with a lead-frame structure is described in the power cycling (P/C) capability which is greatly improved due to a chip surface cooling effect in comparison with aluminum wire interconnection. The lead-frame is joined on a Ni and Au plated chip surface with Sn-Ag or Sn-Sb system solders. The P/C capability obtained with the Sn-Sb system solder is three times larger than that with the Sn-Ag system solder. Such a good performance comes from the solid solution hardening property of Sn-Sb system solder.