Thermal reliability of surface mount leadless solder joints

Numerous studies of failure analysis of leadless solder joints exist in the literature, and a number of life prediction models based on different failure characterising parameters, e.g. total strain, plastic strain, strain energy density, etc., have been developed for particular loading conditions, such as isothermal, or thermal cycling fatigue tests. While a tremendous amount of work has been done, most of them are limited to a deterministic approach that neglects the variation of products due to the uncertainty in the manufacturing process. In this study, several key parameters related to the thermal reliability of the surface mount leadless solder joints were measured from the products. The distributions of these key parameters were used in the probabilistic thermal fatigue analysis to determine the probability of failure for the surface mount leadless solder joints. The non-linear deformation of the solder is considered here, since the creep deformation of the solder is significant during the thermal fatigue.