Mechanical reliability of microelectronics packaging: Small scale adhesion measurements and in-situ imaging

Delamination owed to misfit and thermal stresses is a relevant concern in the field of microelectronics packaging. This study is focused on the adhesion of a polymeric dielectric to inorganic passivation layers and metal caps. In-situ imaging of the delamination phenomena has been achieved by combining 90° peel testing and confocal laser scanning microscopy. This technique has shown promising to enable straightforward segmentation of the bent shape of the peeled layer. The latter has been used to estimate concurring plastic dissipation by means of elastoplastic beam theory and finite element analysis. The results indicate that the actual adhesion energy amounts to ~30% of the external work associated to the measured peel force, which confirms the relevance of in-situ imaging in the field of microelectronics reliability.