Flexible thermal MEMS flow sensor based on Cu on polyimide substrate

A flexible thermal flow sensor based on a Cu on polyimide (COP) substrate was developed for the first time. It has an advantage in that it can be mounted on non-planar surfaces, and, through having a low resistance, it can embed an electrical feed into the COP substrate. Metal film working as a flow sensing element was formed on a thin polyimide membrane produced by sacrificial etching. Flow sensing characteristics, such as the calibration curve and response waveform, were successfully obtained. The relationship between the sensor output and flow rate closely matched the calibration curve derived by King´s law. The obtained response times of both rising and falling were 0.50 s and 0.67 s, respectively.