Fabrication and Measurement of Capacitive Electrostatic Microsensors

• Main Authors: Po-Shun Yang, 楊博勛
• Other Authors: Chi-Chih Lai
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/03787303454532269843

碩士 === 逢甲大學 === 自動控制工程所 === 100 === Based on microelectromechanical system technology, a novel capacitive electrostatic sensor is designed and fabricated for industrial safety detection. The leakage of industrial electrostatic charge can be measured based on deformed capacitive electrodes that caused the capacitance variation due to the charge repulsion effect. Two silicon wafers are used as the substrate. Top electrode and bottom electrode on a movable microstructure are packaged to perform the microelectrostatic sensing structure. The simulation of electrostatic sensing has been executed with different materials and the electrode’s gaps. A unilateral and a bilateral micromechanical variable micromechanics are designed as the sensing structures of the capacitive microsensor. Polyimide film is used as the isolation layer, because of its great thermal stability, good chemical resistance and excellent mechanical properties. The signal processed circuits are designed to transfer measured capacitance variaticus to voltage responses, and the output voltage is ranged between ±5 V. The experimental characterization of the sensing leakage current, variations are from 0 to 100 pF for equivalent electrostatic field from 0 to 22400 V/m. Experimental nonlinear response can be linear processing by three-zone piece-wise-linear approximation that indicates the optimal sensitivity is 56 mV/pF for the capacitance variation from 20 to 80 pF.