Thermal simulation and characterization for the design of ultra-low power micro-hotplates on flexible substrate

This communication reports on the design of ultra-low power micro-hotplates on polyimide (PI) substrate based on thermal simulations and characterization. The goal of this study was, by establishing a simulation model for very small scale heating elements, to decrease the power consumption of PI micro-hotplates to few mWs to make them suitable for very low-power applications. To this end, the mean heat transfer coefficients in air of the devices were extracted by finite element simulations combined with very precise thermographic measurements. A simulation model was implemented to investigate both the influence of the hotplatespsila downscaling and the bulk micromaching of the polyimide substrate to lower their power consumptions. Simulations were in very good agreement to the experimental results. The main parameters influencing significantly the power consumption at such dimensions were identified and guidelines have been established allowing the design of very small (15times15 mum²) and ultra-low power heating elements (6 mW at 300degC). These very low-power heating structures could allow the realization of flexible sensors (gas, flow, wind) for applications in autonomous wireless sensors networks or RFID applications and make them compatible with large scale production on foil such as roll to roll or printing processes.