Effects of various environmental conditions on the electrical properties and interfacial reliability of printed Ag / polyimide system

Effects of 200 °C annealing and 85 °C/85% relative humidity (R.H.) temperature/humidity environments on the electrical resistivity and interfacial adhesion energy between screen-printed Ag film and polyimide substrate were systematically investigated. Measured peel strength was 22.2 gf/mm before environmental treatment, and then decreased to 0.1 and 0.5 gf/mm for annealing and temperature/humidity treatment during 500 hours, respectively. Cu oxide formation at Cu/Ag interface and the degradation of polyimide itself seem to be responsible for adhesion decrease during annealing and temperature/humidity treatments, respectively. Screen printed Ag film shows the initial sharp decrease in resistivity during annealing due to effective binder removal effect and partially sintering effect.