Three-dimensional etching of silicon substrates using a modified deep reactive ion etching technique

Azimi, Sara; Sandoughsaz, A; Amirsolaimani, Babak; Naghsh-Nilchi, J; Mohajerzadeh, S.

doi:10.1088/0960-1317/21/7/074005

Cited by 30 publications

(19 citation statements)

References 21 publications

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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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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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show abstract

“…This method suffers from a cryogenic cooling and certain limitation on masking layer [12]. An alternative process was reported by our group which utilises SF 6 plasma in etching sub-cycle and a mixture of O 2 , H 2 and SF 6 gases in passivation sub-cycle [15][16][17]. This technique uses low-density plasma power and no polymeric passivation is needed.…”

Section: Introductionmentioning

confidence: 99%

Exploitation of semi‐sequential reactive ion etch processes to fabricate in‐plane Si structures

Zarei

Mohajerzadeh

2018

Micro & Nano Letters

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The work reports on the exploitation of semi-sequential deep reactive ion etching (RIE) processes for realisation of deep vertically etched Si structures on Si substrate applicable in fibre-optic sensing systems. These processes employ different mixtures of gases including hexaflourosulphide, hydrogen and oxygen in a RIE system with a programmed passivation and etching sub-cycles. In the so-called semisequential processes, the intermediate purging steps are eliminated, which results in remaining little trace of reactant gases from the previous sub-cycle in the RIE machine's chamber, which can participate in the process of current sub-cycle. For the sake of minimum optical losses, which are accomplished by highly smooth vertical sidewalls, several etching processes were applied. In these processes, by controlling the etching parameters such as the flow of gases, plasma power and timing of each subsequence, the process can be controlled for minimum under-etch and surface roughness and maximum verticality of sidewalls. However, time and cost considerations should also be noted in the optimum fabrication process.

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“…Dry etching of silicon is characterized by some advantages over wet etching. First, dry etching of silicon provides near-vertical sidewalls of the etched cavities [3]. This allows one to increase the quantity of chips on the substrate, thereby reducing their production cost.…”

Section: Introductionmentioning

confidence: 99%

Reactive ion etching of silicon using low-power plasma etcher

Veselov

Bakun

Voronov

2016

J. Phys.: Conf. Ser.

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Abstract. The paper is devoted to the study of deep reactive ion etching of silicon using diode plasma etcher system with a low-power source. Silicon wafers were etched in a sulfur hexafluoride plasma and sulfur hexafluoride/oxygen plasma. The maximum achieved silicon etch rate was about 2 m/min. The expediency of using dry reactive ion etching in combination with wet anisotropic etching of silicon for manufacturing of microelectromechanical systems (MEMS) was demonstrated.

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Three-dimensional etching of silicon substrates using a modified deep reactive ion etching technique

Cited by 30 publications

References 21 publications

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

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

Exploitation of semi‐sequential reactive ion etch processes to fabricate in‐plane Si structures

Reactive ion etching of silicon using low-power plasma etcher

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