Degradation Mechanism of Interfacial Adhesion between Screen-Printed Ag/Polyimide in Temperature/Humidity Environment

The effect of temperature/humidity (T/H) treatment at 85 ℃/85% relative humidity (R.H.) on the peel strength between screen-printed Ag/polyimide (PI) substrate was evaluated using a 180° peel test. Initial peel strength was 22.22 ± 1.00 gf/mm, and then decreased to 0.47 ± 0.22 gf/mm after 500 h at 85 ℃/85% R.H. treatment condition. And, the peeled locus was changed from Ag/PI interface to mixed mode of Ag/PI interface and shallow cohesive inside PI near Ag/PI interface. The decrease in peel strength during T/H treatment is related to formation of weak boundary layer inside PI near Ag/PI interface by hydrolytic degradation of PI due to long-term moisture penetration into the Ag/PI interface.