Effect of annealing on the performance of nickel thermistor on polyimide substrate

In this study, a nickel thermistor pattern integrated with copper electrodes on polyimide substrate is fabricated by photolithography and magnetron sputtering techniques. The effect of annealing treatment on the performance of the nickel thermistor on polyimide substrate is evaluated. It is found that the performance of nickel thermistor is significantly improved by annealing treatment. The relative change of resistance increases with the increasing annealing temperature and time when the annealing temperature is below 360 °C. The temperature range over which the temperature coefficient of resistance (TCR) remains linear is long when the annealing temperature is 350 °C. The adhesion strength between the nickel thermistor and the polyimide substrate significantly increases after annealing treatment, but decreases when the annealing temperature and time increase. From the experimental results, the appropriate annealing temperature and time are obtained to meet required resistance, TCR, adhesion strength of the nickel thermistor.