Fabrication and characterization of flexible pressure sensor arrays made by film transfer technology

This paper presents an efficient and reproducible fabrication process of flexible-substrate-based pressure sensor arrays, using a technology of film transfer which has been recently developed in our laboratory [1]. The sensors are composed of two millimetric copper electrodes, separated by a polydimethylsiloxane (PDMS) dielectric layer, the operation of which is based on a capacitance change induced by an applied force. Sensor arrays were fabricated on two types of substrate: a rigid substrate (glass) used for the validation of the fabrication process, and a flexible substrate (Kapton) used to realize the wanted flexible sensors. Regarding the flexible arrays, a very small curvature radius is possible without any damage to the sensors. Six three-by-three sensor arrays were fabricated. They feature capacitances ranging from 3.45 pF to 14.40 pF, according to their dimensions. The discrepancy between the capacitances within each array is quite low (standard deviation is less than 7 % of the mean value). The sensitivity of the considered on-glass samples is around 80 pF/mN under 2N loading conditions.