Effect of surface finishes on ball shear strength in BGA joints with Sn-3.5 mass% Ag solder

The present Study is aimed at the assessment on the reliability of solder ball attachment to the bond pads of BGA substrate with various plating schemes. The reliability of solder ball attachment is characterized by mechanical ball shear tests. In addition to the ball shear tests, SEM is performed to inspect the cross-section and the fracture surface of the tested specimens for failure analysis. The aging was conducted in convection ovens in air at 343, 393, 423 and 443 K respectively for times ranging 8.64 x 10(4) to 864 x 10(4) s, Without regard to the deposited layer, the shear strength of BGA joints decreased with the increasing temperature and time. After isothermal aging. the fracture surface shows various characteristics depending on aging temperature and time, and the types of BGA pad.