Reliability Evaluation of Ag Sinter-Joining Die Attach Under a Harsh Thermal Cycling Test

Ag sinter-joining is an ideal connection technique for next-generation power electronics packaging due to its excellent high-temperature stability and excellent thermal conductivity. In this work, we applied Ag sinter-joining to die attach of power electronics and focused reliability of Ag sinter-joining under a harsh thermal cycling condition, which ranges from - 50 to 250 degrees C. The bonding quality of assintered die attach had a shear strength of over 45 MPa and remained over 25 MPa after a 500-cycle test. However, the shear strength drastically degraded to less than 10 MPa due to a failure of metallization layer detachment between dummy chip and sputtering layer after 750 cycles. Meanwhile, thermal resistance of die attach with different bonding materials was also evaluated by a T3ster, which suggests the Ag sinter-joining owns a superior property of thermal conduction than the traditional solder joining. This investigation indicates that the Ag sinter-joining has a long lifetime under a severe operating condition of power electronics.