Effect of Polyimide Variation and its Curing Temperature on CMOS Based Capacitive Humidity Sensor and Characterization of Integrated Heater

Abstract

This paper reports humidity sensor using CMOS fabrication technology integrated with micro heater. Vertical capacitive sensor has been chosen having better nominal capacitance. Three different variants of micro heaters were fabricated and compared on both TiN and Poly-phosphorous doped silicon. The bulk-micromachining is carried out for better thermal isolation and further passivation of silicon nitride over heater is carried out for longer operational life. The effects of two different polyimide on the output capacitance have been shown. Also, the effect of curing temperature and ion implantation on the output capacitance has also been detailed.

Keywords

• Bulk-micromachining
• Capacitive sensor
• Polyimide
• Micro-heater