Electrical and Electrochemical Migration Characteristics of Ag/Cu Nanopaste Patterns

摘要

Since direct printing technology has developed intensively, low-cost fabrication and reliability have become critical challenges for mass production of printed electronic devices. The silver/copper (Ag/Cu) nanopaste was manufactured by Ag nanopaste mixed with different proportions of Cu nanoparticles ranging from 0 to 5 vol.% in order to investigate the influences of Cu content on the electrical properties and electrochemical migration (ECM) characteristics. The patterns were constructed on a glass wafer via screen printing with the Ag/Cu nanopaste. They were then annealed through debinding for 30 min in air followed by sintering for 30 min in a hydrogen atmosphere at various temperatures (150, 200, 250, and 300℃). The electrical resistivity of printed patterns that were sintered at 150℃ grew with increases in the percentage of Cu content in the Ag/Cu nanopaste, while printed patterns that were sintered at 300℃ show similar electrical resistivity values of around 2～3 μΩ cm regardless of Cu content. The ECM characteristics of the printed patterns were evaluated by performing a water drop test. The printed patterns that were sintered at higher temperatures showed longer ECM times. At 300℃, the ECM time was considerably lengthened when the Cu content was over 2 vol.%, and the 5 vol.% Cu pattern showed the longest ECM time of 305 s, which was around 1.65 times that of the Ag pattern.