Study of adhesion failure due to molding compound additives at chip surface in electronic devices

Today the microelectronics market requires devices with failure levels appr oaching zero. To attain this goal all production processes must be subjecte d to extreme quality control. Molding is one of the most critical assembly processes in power plastic packages. This is related to the complexity of p henomena which may occur at the interfaces involved in this process. This p aper reports an adhesion study of epoxy-phenolic molding compounds to the m ost relevant surfaces encountered in power devices assembled in plastic pac kages such as copper oxide-hydroxide, nickel oxide-hydroxide, aluminium oxi de-hydroxide, and silicon 'nitride'. The study was carried out by combining delamination (scanning acoustic microscopy) and pull strength data with th e interface chemistry studied using ESCA. Different adhesion failure mechan isms were found to be operative in these systems. These mechanisms are rela ted to either the chemical nature and thickness of the inorganic layer or t he segregation of various additives such as wax, polyoxyalkylene ethers, an d alkylsiloxanes, contained in the molding compound.