Enhancing Efficiency in Packaging Substrate Reliability Evaluation Through AC Electrical Resistivity Measurement

The reliability assessment of packaging substrates is essential for both the design and quality control of electronic devices. However, such evaluations often involve prolonged testing periods, which potentially impede the development and optimization of substrates. In this study, two distinct substrates were fabricated with identical circuit designs and layered materials, differing only in the manufacturing processes of their microvias used for interconnection. Substrate A exhibited a higher void fraction at the microvia bottom than substrate B. Both substrates were subjected to thermal shock testing under cyclic conditions of -55°C for 15 min followed by 150°C for 15 min, with testing continued for over 1000 cycles. Electrical resistance was continuously monitored using either an alternative current (AC) or a direct current (DC)), with voltage measurements taken accordingly. A circuit was considered to have failed when its resistance first reached an infinite value. Failed cycle numbers were further analyzed using a Weibull plot. The results indicated that both AC and DC measurement consistently demonstrated lower reliability for substrate A compared to substrate B. However, the cumulative failure rate F(10%) was observed to be shorter when measured using AC than with DC. These findings indicate that AC-based resistance monitoring resulted in an approximately 25% reduction in testing duration for both substrates compared to DC-based measurements. This study suggests that switching from DC to AC electrical resistance measurements can significantly shorten reliability evaluation periods while maintaining assessment accuracy.