One-chip multichannel quartz crystal microbalance (QCM) fabricated by Deep RIE

In this paper, we present a one-chip multichannel quartz crystal microbalance (QCM) sensor fabricated by deep reactive ion etching (Deep RIE). An inductively coupled plasma reactive ion etching (ICP RIE) using SF, gas has been applied to the Deep RTE of quartz. High etch rate (similar to 0.5 mu m/min) and mirror surface (roughness, similar to 2 nm) were achieved at the conditions of low process pressure (2 mTorr) and high self-bias voltage (- 340 V). The multichannel QCM sensor, which has different resonance frequencies, was formed by fabricating diaphragms of different thicknesses on a single crystal of quartz plate. The resonance frequencies ranged from 21.7 to 20.75 MHz. The Q factors of each peak were approximately 2000 in air and the resolution for mass change was +/-1 ng on 2-mm-diameter electrode. We have successfully shown that the sensor with different coating films can be applied to chemometric odor sensor. (C) 2000 Elsevier Science S.A. All rights reserved.