Evaluation of fracture energy and anti-hydrolysis property of the Al/PI interface. (a) Illustration showing how the interfacial fracture energy was quantitatively measured via an asymmetric double cantilever beam (ADCB) test. The right photograph showing how the ADCB test was actually conducted. (b) to (d) Initial aluminum, fracture aluminum surface, and zoom-in image of in (c). (e) to (g) Initial polyimide, fracture polyimide surface, and zoom-in image of in (f). All the fracture surfaces were taken from crack tip ahead of the blade. To enhance topographical contrasts, (c), (f) and (g) were taken at a tilt angle 30°. (h) Photograph showing the ADCB-tested specimen after the temperature humidity storage (85 °C/85RH%) for 1000 h. The blade was inserted from the upper edge of the specimen down into the interface.