Alpern, P.P.AlpernDudek, R.R.DudekSchmidt, R.R.SchmidtWicher, V.V.WicherTilgner, R.R.Tilgner2022-03-032022-03-032002https://publica.fraunhofer.de/handle/publica/20111210.1109/6144.991176Experiments were carried out using P-TQFP-176 packages to study the mode II popcorn effect in thin packages. The doming of the package backside was measured as a function of time and temperature. The measurements were performed using a line projection method. An "accelerated" increase in the doming was found to correlate with the onset of the package crack propagation. It was shown that when a constant critical doming angle is reached, package cracks begin to propagate toward the surface. This critical doming angle was found to be temperature independent between 170°C and 215°C. Furthermore the development of the package doming with time was described by a simple model based on the moisture diffusion from molding compound and die-attach material in combination with a bimaterial plate theory. The water content of the die-attach layer after preconditioning was calculated from the model and it was found to be in good agreement with the results of a three dimensional finite element simulation.en621journal article