Study on the Ion Migration of Silver Ions from Aqueous Solution in Epoxy-Based Molding Compounds by TOF-SIMS Measurements

Abstract

Epoxy molding compounds are typically used for the encapsulation of modern-day electronic devices. These protect the semiconductor components from environmental influences, such as humidity and oxygen, which could harm the device. However, there is still a risk for corrosion phenomena, when the device is used in harsh conditions (e.g. high humidity and temperature). Electrochemical migration is a mechanism that can occur in the semiconductor device. For instance, silver wires, glues, solders or leadframe-platings used in the package combined with high humidity contact are a huge risk. For this type of corrosion to happen, Ag ions need to migrate through the molding compound. Therefore, measurement of the diffusion coefficient of silver ions in molding compounds can help to better predict the risk of silver migration and corrosion. In this study silver(I)salts were used source for Ag + ions. An Arrhenius correlation was found in the range from 298 K to 393 K. The diffusion coefficient as well as the activation energy of silver ions in four different molding compounds have been evaluated. The investigated activation energies as well as diffusion coefficients are in the range of 0.12 to 0.50 eV.