Fabrication of a LCP-based conductivity cell and resistive temperature device via PCB MEMS technology

Printed circuit board microelectromechanical systems are a set of fabrication techniques that use traditional inexpensive printed circuit board processes to construct microsensors. These techniques keep gaining popularity and are utilized herein. The design, fabrication and construction of a miniature, low-cost conductivity cell and resistive temperature device transducers are presented. The transducers utilize a liquid crystal polymer (LCP), a thin-film material, which exhibits moisture resistant properties that makes it suitable for aquatic applications. Novel processing techniques that are reported here include the use of a direct-write photolithography tool eliminating the use of photomasks and chemical catalytic metallization of LCP material. The rapid fabrication of these devices and the repeatability of the fabrication are demonstrated by comparing the calibration of multiple devices. The sensors'sensitivities are found to be 1082.40 +/- 144.18 mS cm-1 per siemens and 5.910 +/- 0.765 deg C per ohm for the conductivity and temperature transducers, respectively.