Taking residual stress in wafer level packaging（ WLP） with Al-Ge bonding as research object

a series of resistor stripe with the same shape are fabricated beneath or adjacent to the bond pad. Analyze magnitude of residual stresses on resistors strip and its correlation with the process by comparing resistance variation of resistor stripe before and after bonding. Results show that the resistance variation of piezoresistors inside and outside the bond pad is three times larger than that beneath the bond pad. This method can be one of the effective means for online characterization of wafer level bonding quality.