Electrical reliability of electrically conductive adhesive joints: dependence on curing condition and current density

The use of electrically conductive adhesives as interconnection materials in electronic assembly process is increasingly becoming a vital part of the electronics industry. Flip-chip joining technique using conductive adhesives has been identi®ed as a key technology for future electronics assembly and manufacturing. The purpose of the present work is to investigate optimum conditions to achieve the best electrical performance in conductive adhesive joints. This study shows a comparison of electrical performance in conductive adhesive joints at various current densities with different curing conditions. Differential scanning calorimetry and resistance measurement were used to monitor curing condition in conductive adhesives. Accelerated life testing of conductive adhesive joints made of the selected conductive adhesive using different curing conditions was performed with various current densities. The current-induced degradation of conductive adhesive joints was investigated using optical microscopy and electrical resistance measurements. Results show a strong dependence of curing condition and current density on electrical performance of adhesive joints. Additionally, sample cured for less time exhibited better quality than sample cured for more time at high current densities. It is also found that conducting particles move with the current-induced aging, which shows that the migration of conducting particles can induce the failure of conductive adhesive joint during the current-induced resistance increase. q 2001 Elsevier Science Ltd. All rights reserved.