Reliability Evaluation of Micro Heater and its Application for Automotive Sensors

Abstract

A heat resistant micro heater consisting of a Pt thin film and a diaphragm was developed for automotive sensors and its reliability was evaluated from the mechanical and thermal points of view. The dominant failure modes for instant overheating and longtime heating were found to be de-lamination of the Pt film and electromigration of Pt, respectively. The life time was estimated to be over 10 years when the average heater temperature was 400°C (the peak temperature was over 600°C). As automotive sensors utilized this micro heater, the developed air flow meter and air quality sensor are described with features and evaluation methods unique to these sensors.