Thermomechanical assessment of molding compounds

A bending beam technique was used to classify different molding compounds by the shear stress exerted on the Si substrate. Production test chips encapsulated with these plastic materials were stressed by means of temperature cycling. The amount of mechanical degradation of the chips as determined after decapsulation turned out to be clearly correlated with the shear stress exerted by the plastic. Thus the bending beam technique allows the assessment of the components´ quality with respect to thermal cycling stress