Title :
Improvement of polyimide capacitive humidity sensor by reactive ion etching and novel electrode design
Author :
Yang, Ya Ling ; Lo, Lieh Hsi ; I Yu Huang ; Chen, Henry J H ; Wen Shen Huang ; Huang, I. Yu
Author_Institution :
Inst. of Electron. Eng., Nat. Tsing Hua Univ., Hsinchu, Taiwan
Abstract :
In this study, we demonstrate a highly sensitive polyimide capacitive humidity sensor achieved by reactive ion etching microstructures in polyimide film and novel electrode designs. For sensors of 3 /spl mu/m polyimide film, the sensitivity is improved from 0.8 to 1.24 (pF/%RH) over the relative humidity ranging from 50 to 80. The hysteresis is within 2.5 (%RH). The device has 1600 humidity admittance square holes etched 2 /spl mu/m deep in the polyimide sensing film, and its bottom electrode was patterned to reduce the less sensitive capacitor area to increase the dC/C ratio, and hence increase the sensitivity of the sensors.
Keywords :
capacitive sensors; electrodes; humidity sensors; polymer films; sensitivity; sputter etching; 2 micron; 3 micron; capacitive humidity sensor; capacitor area; electrode design; humidity admittance square holes; polyimide sensing film; reactive ion etching; relative humidity; sensitivity; Admittance; CMOS technology; Capacitive sensors; Capacitors; Electrodes; Etching; Fabrication; Humidity; Polyimides; Temperature sensors;
Conference_Titel :
Sensors, 2002. Proceedings of IEEE
Conference_Location :
Orlando, FL, USA
Print_ISBN :
0-7803-7454-1
DOI :
10.1109/ICSENS.2002.1037147
