Moisture Resistance of Polyimide Multilevel Interconnect LSI´s

The moisture resistance of polyimide multilevel interconnect LSI´s is evaluated. A polyimide type resin, PIQ®, is used. Wear-out failures of the PIQ interconnects with pure Al metallization occur during high temperature/humidity (T&H) accelerated test such as 65°C/95% RH storage. Intergranular corrosion of second or third-level Al lines on PIQ is found to be the main cause of the failures. The interconnect failure mechanism is also discussed. It is shown that remarkable moisture resistance improvement is achieved by employing Al-Si metallization. The lifetime of the interconnect with Al-Si metallization is estimated to be over 100 years.