Packaging solution for a novel silicon-based trace humidity sensor using coulometric method

For a large number of industrial, technical processes and in aerospace science, the monitoring and control of water content of solid, liquid, or gaseous materials is a central and quality determining task [1]. In this paper we present our work on development of a humidity sensor array for detecting of absolute trace humidity using Pt-P2O5 electrolytic cells. Many sensor solutions on the market are using this material system for detecting of humidity. Disadvantages of these systems are their non-ability to monitor the absolute amount of water in air and their limited robustness and redundancy. One of important focuses in this work is the development of a robust and stable package for the developed sensor system. The package has to protect the sensors from surrounding, but has to provide the interface between the sensor surface and the atmosphere and a sensor electrical interface for electronics. For a reliable detection of humidity in air, a constant and laminar flow over the sensor surface is needed. The system is containing 4 sensors (cells) in a row, which allows detection of total water in the air. Our realized sensor system shows a high reliable and accurate behavior and is suitable for use in aerospace and industry [2].