Mechanism-based delamination prediction during reflow with moisture preconditioning

In this paper, a vapor pressure model, based on a micromechanics approach, is introduced first, with which the moisture absorption and porosity of the material, and the temperature can be connected. Then the neo-Hookean model is used to describe the finite-deformation of rubberlike plastic materials at higher temperature. It has been observed that the vapor pressure has almost negligible impact on the material behavior in bulk. However, with the implementation of interface properties into the model study, it shows that the critical stress that results in the unstable void growth and delamination at the interface is significantly reduced and becomes comparable to the magnitude of the vapor pressure. A framework of the description of void-growth at the interface is postulated.