Calibration-less method for measuring pressure with microfabricated Pirani gauges

摘要

We present a method for measuring vacuum levels with micro-Pirani gauges which does not require calibration against pressure. This is particularly useful for gauges enclosed in vacuum-packaged dies, where pressure cannot be varied for calibration. Our method uses an analytical model which is fitted to the electrical measurements performed on the dies. In order to improve the accuracy of the method, we also propose several ways to determine the unknown inputs required to calculate pressure. One of these is to combine measurements made on several gauges with different geometries. Finally we apply our method with gauges designed and fabricated for this application.