Sidewall Imaging of Microstructures with a Tilted Quartz Tuning Fork (QTF) Force Sensor

Hussain, Danish; Yan, Wen; Xie, Hui

doi:10.1109/marss.2018.8481199

Cited by 2 publications

(1 citation statement)

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“…Quartz has been widely used as a resonator material in micro-sensors [ 1 , 2 , 3 ] due to its excellent material properties such as its high quality factor [ 4 , 5 , 6 , 7 , 8 , 9 , 10 ], high frequency stability and inherent piezoelectric characteristics. A major obstacle limiting the wide use of quartz is that there exists a limited variety of suitable processing methods for producing structures with desired shapes.…”

Section: Introductionmentioning

confidence: 99%

Deep Reactive Ion Etching of Z-Cut Alpha Quartz for MEMS Resonant Devices Fabrication

Zhao

et al. 2020

Micromachines

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Quartz is widely used in microelectromechanical systems (MEMS). Especially, MEMS quartz resonators are applied to sensors and serve as sensitive elements. The capability of deep etching is a limitation for the application. Presented in this paper is a deep and high accuracy reactive ion etching method applied to a quartz resonator etching process with a Cr mask. In order to enhance the capability of deep etching and machining accuracy, three kinds of etching gas (C4F8/Ar, SF6/Ar and SF6/C4F8/Ar), bias power, inductively coupled plasma (ICP) power and chamber pressure were studied in an industrial reactive ion etching machine (GDE C200). Results indicated that the SF6/C4F8/Ar chemistry gas is the suitable and optimal choice. Experiment results indicate that Cr (chromium) mask can obtain a higher selectivity than aluminum and titanium mask. A “sandwich” structure composed of Al layer-Cr layer-Al layer-Cr layer was proposed. The Al (aluminum) film can play the role of releasing stress and protecting gold electrodes, which can enhance the thickness of metal mask. An optimized process using SF6/C4F8/Ar plasmas showed the quartz etching rate of 450 nm/min. Meanwhile, a microchannel with a depth of 75.4 µm is fabricated, and a nearly vertical sidewall profile, smooth surface is achieved.

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