Fabrication of micro-trench structures with high aspect ratio based on DRIE process for MEMS device applications

Guo, Maoxiang; Chou, Xiujian; Mu, Jiliang; Liu, Bing; Xiong, Jijun

doi:10.1007/s00542-012-1720-9

Cited by 10 publications

(8 citation statements)

References 6 publications

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“…3(b). A minimum section width of 0.04 mm and a length of 1.093 mm were obtained according to the advanced silicon deep reactive ion etching (DRIE) technique on 450 µm-thick silicon wafers 34,[38][39][40] in Fig. 4.…”

Section: Structural Design and Fabrication Of The Micropumpmentioning

confidence: 99%

Modeling, Vibration Analysis and Fabrication of Micropumps Based on Piezoelectric Transducers

Guan¹,

Meng²,

Liu³

et al. 2020

The International Journal of Acoustics and Vibration

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The parametric and vibrational characteristics of PZTs (Piezoelectric Transducers) with different diameters before and after coupling are discussed by finite element analysis. It is shown that the vibration stability of the piezoelectric transducer decreases with increasing driving frequency. The PZT's variation of maximum displacement with frequency shows the same trend for different driving conditions according to vibration measurement under conditions of both free and forced vibration (before and after sealing with the pump body). The maximum displacement under forced vibration is less than that under free vibration. The maximum displacement is inversely proportional to the diameter of the transducer and directly proportional to the driving voltage under both free and forced vibration. Micropumps with diffuser/nozzle microvalves are designed and fabricated with different external diameters of the PZTs. Finally, the flow rate and pressure of the micropumps are measured, which are consistent with the vibrational results. Moreover, the maximum displacement is larger under a square-wave driving signal, followed by a sine-wave signal, and then a triangle-wave signal. For a PZT with an external diameter of $12$ mm, the maximum flow rate and pressure value are $150$~$upmu$l/min and $346$ Pa, respectively, under sine-wave driving at $100$ Vpp driving voltage.

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Section: Structural Design and Fabrication Of The Micropumpmentioning

confidence: 99%

Modeling, Vibration Analysis and Fabrication of Micropumps Based on Piezoelectric Transducers

Guan¹,

Meng²,

Liu³

et al. 2020

The International Journal of Acoustics and Vibration

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“…Some researchers have reported HAR structure fabrication, [5][6][7] but the fabrications can only be demonstrated on silicon substrates. Although some literatures have demonstrated very smooth silicon sidewalls 8,9 after etching of SOI wafers, the reported aspect ratios still remain low. Therefore, the DRIE technology is continuously improved, but it is still very difficult to obtain a HAR feature with vertical and smooth silicon etching sidewalls for SOI wafers with a relatively thick device layer.…”

Section: Introductionmentioning

confidence: 96%

Fabrication of high aspect ratio structure and its releasing for silicon on insulator MEMS/MOEMS device application

Fan

Zhang

Liu

et al. 2015

J. Micro/Nanolith. MEMS MOEMS

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We systematically investigate the fabrication and dry-release technology for a high aspect ratio (HAR) structure with vertical and smooth silicon etching sidewalls. One-hundred-micrometer silicon on insulator (SOI) wafers are used in this work. By optimizing the process parameters of inductively coupled plasma deep reactiveion etching, a HAR (∼25∶1) structure with a microtrench width of 4 μm has been demonstrated. A perfect etching profile has been obtained in which the structures present an almost perfect verticality of 0.10 μm and no sidewall scallops. The root-mean square roughness of silicon sidewalls is 20 to 29 nm. An in situ dry-release method using notching effect is employed after etching. By analysis, we found that the final notch length is typically an aspect-ratio-dependent process. The structure designed in this work has been successfully released by this in situ dry-release method, and the released bottom roughness effectively prohibits the stiction mechanism. The results demonstrate potential applications for design and fabrication of HAR SOI MEMS/MOEMS.

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“…Since scalloping is not acceptable in specific applications, a dedicated effort has been provided to control and reduce it, mainly based on the optimization of DRIE process parameters [47][48][49][50], or, alternatively, removing it after fabrication [38].…”

Section: Introductionmentioning

confidence: 99%

Scalloping and Stress Concentration in DRIE-Manufactured Comb-Drives

et al. 2018

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In the last decades, microelectromechanical systems have been increasing their number of degrees of freedom and their structural complexity. Hence, most recently designed MEMSs have required higher mobility than in the past and higher structural strength and stability. In some applications, device thickness increased up to the order of tens (or hundred) of microns, which nowadays can be easily obtained by means of DRIE Bosch process. Unfortunately, scalloping introduces stress concentration regions in some parts of the structure. Stress concentration is a dangerous source of strength loss for the whole structure and for comb-drives actuators which may suffer from side pull-in. This paper presents an analytical approach to characterize stress concentrations in DRIE micro-machined MEMS. The method is based on the linear elasticity equations, the de Saint-Venant Principle, and the boundary value problem for the case of a torsional state of the beam. The results obtained by means of this theoretical method are then compared with those obtained by using two other methods: one based on finite difference discretization of the equations, and one based on finite element analysis (FEA). Finally, the new theoretical approach yields results which are in accordance with the known value of the stress concentration factor for asymptotically null radius notches.

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Fabrication of micro-trench structures with high aspect ratio based on DRIE process for MEMS device applications

Cited by 10 publications

References 6 publications

Modeling, Vibration Analysis and Fabrication of Micropumps Based on Piezoelectric Transducers

Modeling, Vibration Analysis and Fabrication of Micropumps Based on Piezoelectric Transducers

Fabrication of high aspect ratio structure and its releasing for silicon on insulator MEMS/MOEMS device application

Scalloping and Stress Concentration in DRIE-Manufactured Comb-Drives

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