Abstract: The present invention discloses a temperature sensor. The temperature sensor includes an aluminum oxide substrate and a thin-film resistor having a specific temperature coefficient of resistance (TCR) disposed over the substrate. The temperature sensor further includes an aluminum oxide stress-relief layer covering the thin film resistor. The temperature sensor further includes a passivation layer covering the aluminum oxide stress-relief layer. The aluminum oxide stress-relief layer further has at least one resistor-trimming trench formed by removing a portion of the aluminum oxide stress-relief layer and thin-film resistor therefrom and the resistor-trimming trench is filled with a material of the passivation layer. In a preferred embodiment, the temperature sensor further includes a set of dummy pads for resistance-trimming measurement disconnected from the thin film resistor disposed on the substrate near the thin film resistor covered by the passivation layer.