THERMAL-SHOCK TEST OF INTEGRATED-CIRCUIT PACKAGES SEALED WITH EPOXY MOLDING COMPOUNDS FILLED WITH SPHERICAL SILICA PARTICLES

The effect of filler silica particle size on the properties of integrated circuit (IC) packages sealed with epoxy moulding compound was studied. For this purpose, four epoxy moulding compounds filled with spherical silica particles having mean sizes in the range 6 approximately 31 mum were prepared. Critical stress intensity factor (K(c)) and flexural strength (sigma) of the cured epoxy moulding compounds were measured. As the particle size increased, the K(c) value increased and the sigma value decreased. The thermal shock test was carried out: IC packages were repeatedly dipped alternately in liquids at - 65-degrees-C and 150-degrees-C and the occurrence of package cracking was observed. The cracking took place at an earlier stage of the thermal shock test when the particle size was smaller. There was a good relationship between the thermal shock test result and the K(c) value.