Integration of MOX gas sensors on polyimide hotplates

• Published in: Sensors and actuators. B, Chemical Chemical, 2008-03, Vol.130 (1), p.430-435
• Main Authors: Briand, D., Colin, S., Courbat, J., Raible, S., Kappler, J., de Rooij, N.F.
• Format: Article
• Language: English
• Subjects: Arrays; Gas sensors; Metal oxides; Metal-oxide (MOX); Plastic gas sensors; Polyimide hotplates; Polyimide resins; Polymeric gas sensors; Sensors; Sheet metal; Silicon substrates; Tin oxides; Wafer level packaging
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2007.09.013

In this communication, we report on the integration of metal-oxide gas sensors on polymeric micro-hotplates made on polyimide and silicon substrates. Low-power consumption micro-hotplates with platinum electrodes and heaters were fabricated on polyimide membranes. Their thermal behavior was optimized using temperature probing at the micro-scale level coupled with thermal simulations. Tin oxide thick films were successfully integrated on these polyimide micro-hotplates using the drop coating technique. The annealing process of the tin oxide drops on the polyimide substrate was investigated and gas measurements are presented. Compared to the polyimide hotplates on silicon substrates, the hotplates made on polyimide sheets are simpler to process and more robust, and therefore, they are more suitable for the integration of metal-oxide films. Finally, a wafer level packaging technique using multiple polyimide layers was developed and led to a polymeric platform for metal oxide sensors. The technology is also promising for the integration of polyimide humidity sensors, of resistive and capacitive gas-sensitive polymeric films to realise fully flexible gas sensor arrays.