Parylene micro membrane capacitive sensor array for chemical and biological sensing

The need for high-throughput label-free multiplexed sensors for chemical and biological sensing has increased tremendously in the last decade with new applications in the areas of genetics, diagnostics, drug discovery, as well as security and threat evaluation. Surface stress-based sensors are a relatively new class of sensors that has immense potential to satisfy the demand, and has been investigated extensively in the recent years. In this paper we present the design and fabrication of a novel parylene micro membrane surface stress sensor that exploits the low mechanical stiffness of polymers. The salient features of the sensor are that it: (i) is label-free; (ii) is a universal platform suitable for both chemical and biological sensing; (iii) uses electronic (capacitive detection) readout; (iv) has integrated microfluidics for addressing individual sensors on the chip; (v) is capable of handling both liquid and gas samples; (vi) is made using standard low temperature microfabrication processes (<120 °C); (vii) can readily be scaled and multiplexed. The first generation sensor arrays were fabricated and the sensor response to organic vapors like isopropyl alcohol and toluene were measured.