A study on the flammability of halogen-free core materials for microelectronic packaging substrates

The objective of this study is to investigate how filled core materials with halogen-containing and halogen-free flame retardants affect the flammability behavior. In this study, a thermogravimetric analyzer (TGA) was applied to study the thermal decomposition behavior of filled core materials with increasing temperature. A scanning electron microscope (SEM) was used to investigate the morphology of the filled core materials. Energy disperse spectroscopy (EDS) and dynamic scanning calorimetry (DSC) were used to identify the type of halogen-free flame retardant that was added to the core materials and relate it to the effect on the flammability of the core materials. Electron spectroscopy for chemical analysis (ESCA) was used to identify the content and the chemical bonding of the filled core materials and how this affects the flammability, which was tested by UL-94, for evaluating the propagation of burning and limited oxygen index (LOI), for interpreting the minimum oxygen content required for burning.