Realization of complex three-dimensional free-standing structures on silicon substrates using controllable underetching in a deep reactive ion etching

Sandoughsaz, A; Azimi, Sara; Mazreati, H; Mohajerzadeh, S.

doi:10.1088/0960-1317/23/3/035022

Cited by 12 publications

(5 citation statements)

References 31 publications

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“…In addition to vertical etching, by adjusting the etching and passivation parameters, three-dimensional structure can be obtained. For the formation of the latter features, etching recipe must be altered to reach desired under etching [13][14][15].…”

Section: Methodsmentioning

confidence: 99%

A novel non-sequential hydrogen-pulsed deep reactive ion etching of silicon

Gharooni¹,

Mohajerzadeh²,

Sandoughsaz³

et al. 2013

J. Micromech. Microeng.

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A non-sequential pulsed-mode deep reactive ion etching of silicon is reported that employs continuous etching and passivation based on SF6 and H2 gases. The passivation layer, as an important step for deep vertical etching of silicon, is feasible by hydrogen pulses in proper time-slots. By adjusting the etching parameters such as plasma power, H2 and SF6 flows and hydrogen pulse timing, the process can be controlled for minimum underetch and high etch-rate at the same time. High-aspect-ratio features can be realized with low-density plasma power and by controlling the reaction chemistry. The so-called reactive ion etching lag has been minimized by operating the reactor at higher pressures. X-ray photoelectron spectroscopy and scanning electron microscopy have been used to study the formation of the passivation layer and the passivation mechanism.

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Section: Methodsmentioning

confidence: 99%

A novel non-sequential hydrogen-pulsed deep reactive ion etching of silicon

Gharooni¹,

Mohajerzadeh²,

Sandoughsaz³

et al. 2013

J. Micromech. Microeng.

Self Cite

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“…The conical shape of the shanks and tips shown above is naturally obtained through a special feature of the DRIE etch step called DRIE lag effect. DRIE etch rate is inversely proportional to the aspect ratio of the hole/trench, in other words, holes/trenches with higher ratio of depth to width are etched slower [29][30][31][32][33][34][35]. The variable etch rate at different depths will result in the conical shape of the shank, producing a sharp tip which improves probe insertion into the tissue.…”

Section: Probe Shank Conical Shape and Tip Sharpnessmentioning

confidence: 99%

Sea of Electrodes Array (SEA): Extremely Dense and High-Count Silicon-Based Electrode Array Technology for High-Resolution High-Bandwidth Interfacing with 3D Neural Structures

Zardini¹,

Rostami²,

Najafi³

et al. 2021

Preprint

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In this work, we propose a new silicon-based micro-fabrication technology to fabricate 3D high-density high-electrode-count neural micro-probe arrays scalable to thousands and even millions of individual electrodes with user-defined length, width, shape, and tip profile. This unique technology utilizes DRIE of ultra-high aspect-ratio holes in silicon and refilling them with multiple films to form thousands of individual needles with metal tips making up the “sea-of-electrodes” array (SEA). World-record density of 400 electrodes/mm2 in a 5184-needle array is achieved. The needles are ~0.5-1.2mm long, <20μm wide at the base, and <1μm at the tip. The silicon-based structure of these 3D array probes with sharp tips, makes them stiff enough and easily implantable in the brain to reach a targeted region without failing. Moreover, the high aspect ratio of these extremely fine needles reduces the tissue damage and improves the chronic stability. Functionality of the electrodes is investigated using acute in vivo recording in a rat barrel field cortex under isoflurane anesthesia.

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“…using wet etching [7], [8], or more commonly ,plasma etching (also called dry etching). Some of the dry etching methods reported before rely on an additional oxidation procedure to protect the sidewall of the structures during the dry release step [9], [10], however, the oxidation step and bottom opening step add extra fabrication complexity. Some other studies make use of the scallops generated during a Bosch process and the self-limited oxidation process [3], however, the removal of the oxide layer after the etching process requires special techniques, such as vapor release or critical drying release, especially for nanostructures, which are easily collapse under capillary forces.…”

Section: Introductionmentioning

confidence: 99%

DREM2: a facile fabrication strategy for freestanding three dimensional silicon micro- and nanostructures by a modified Bosch etch process

Chang

Jensen

Hübner

et al. 2018

J. Micromech. Microeng.

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show abstract

Realization of complex three-dimensional free-standing structures on silicon substrates using controllable underetching in a deep reactive ion etching

Cited by 12 publications

References 31 publications

A novel non-sequential hydrogen-pulsed deep reactive ion etching of silicon

A novel non-sequential hydrogen-pulsed deep reactive ion etching of silicon

Sea of Electrodes Array (SEA): Extremely Dense and High-Count Silicon-Based Electrode Array Technology for High-Resolution High-Bandwidth Interfacing with 3D Neural Structures

DREM2: a facile fabrication strategy for freestanding three dimensional silicon micro- and nanostructures by a modified Bosch etch process

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