Investigation of Degradation Behavior of Adhesion between Sealing Resin and Copper by Aging Treatment

The degradation behavior of adhesion between cycloaliphatic epoxy resin and copper under high temperature and high humidity conditions was investigated. The Cu/resin joints were aged at 175°C and at 85°C in 85% R. H. The degradation behavior of the joint interface was analyzed by tensile tests and Fourier infrared transform spectroscopy (FT-IR). As a result, it was confirmed that the adhesion strength was retained after aging at 175°C for 1000 h, while it decreased with an increase in the aging time by aging at 85°C in 85% R. H. Furthermore, the interfacial fracture mode increased with aging at 175°C. In contrast, cohesive fracture was the main fracture mode and hardly changed by aging at 85°C in 85% R. H. The FT-IR analysis results showed that the peak intensity of the carbonyl group increases and that of the methylene group decreases by aging at 175°C. The result indicates that the resin was oxidized. Moreover, the peak intensities of carboxy and hydroxyl groups increased and that of ester groups decreased by aging at 85°C in 85% R. H. The results suggest that ester groups may be hydrolyzed due to aging and thus the adhesion is degraded.