Effects of Dielectric Curing Temperature on the Interfacial Reliability of Cu/Ti/PBO for FOWLP Applications

In this study, the effect of curing temperatures of low-temperature curable polybenzoxazole (PBO) dielectrics on the interfacial adhesion energies between the Cu redistribution layer and PBO dielectric used in advanced fan-out packaging was systematically investigated using a four-point bending test. The results revealed that the interfacial adhesion energy increased when the PBO curing temperature increased from 175 to 200 °C, whereas it decreased when the curing temperature increased from 200 to 225 °C. The increase in the interfacial adhesion energy with an increase in the PBO curing temperature from 175 to 200 °C is attributed to the polymerization of PBO. However, the decrease in the interfacial adhesion energy as the curing temperature increases to 225 °C results from thermal stress.