Control of shape of silicon needles fabricated by highly selective anisotropic dry etching

Kanechika, Masakazu; Sugimoto, Noriaki; Mitsushima, Yasuichi

doi:10.1116/1.1484100

Cited by 18 publications

(11 citation statements)

References 13 publications

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“…Alternative approaches to the fabrication of micro-needles have been described [14], [15] but the approach presented here is simpler, only requiring a change in the diameter of the needle body mask rather than adjustments to process parameters.…”

Section: Fig 2 (A)-(d)mentioning

confidence: 99%

A systematic approach to fabricate high aspect ratio silicon micro-needles for transdermal drug delivery

Shearwood

2007

BioMEMS and Nanotechnology III

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The successful development of micro-needles can help transport drugs and vaccines both effectively and painlessly across the skin. However, not all micro-needles are strong enough to withstand the insertion forces and viscoelasticity of the skin. The work here focuses on the micro-fabrication of high aspect ratio needles with careful control of needleprofile using dry etching technologies. Silicon micro-needles, 150µm in length with base-diameters ranging from 90 to 240µm have been investigated in this study. A novel, multiple-sacrificial approach has been demonstrated as suited to the fabrication of long micro-needle bodies with positive profiles. The parameters that control the isotropic etching are adjusted to control the ratio of the needle-base diameter to needle length. By careful control of geometry, the needle profile can be engineered to give a suitable tip size for penetration, as well as a broad needle base to facilitate the creation of either single or multiple-through holes. This approach allows the mechanical properties of the otherwise brittle needles to be optimized. Finite element analysis indicates that the micro-needles will fracture prematurely due to buckling, with forces ranging from 10 to 30mN.

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Section: Fig 2 (A)-(d)mentioning

confidence: 99%

A systematic approach to fabricate high aspect ratio silicon micro-needles for transdermal drug delivery

Shearwood

2007

BioMEMS and Nanotechnology III

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“…O ne of the recent advances in the conversion efficiency improvement of solar cells [1][2][3][4][5][6][7] and application to terahertz emitter, 8) is the use of "black silicon (Si)", which is an attractive concept in terms of photon capture and trapping. However, the standard fabrication method for black Si was relatively complex from the industrial point of view because a wet process or reactive ion etching (RIE) is employed with some masks.…”

mentioning

confidence: 99%

Nanostructure formation on silicon surfaces by using low energy helium plasma exposure

Takamura

Kikuchi

Yamada³

et al. 2016

Jpn. J. Appl. Phys.

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A new technology for obtaining nanostructure on silicon surface for potential applications to optical devices is represented. Scanning electron microscope analysis indicated a grown nanostructure of dense forest consisting of long cylindrical needle cones with a length of approximately 300 nm and a mutual distance of approximately 200 nm. Raman spectroscopy and spectrophotometry showed a good crystallinity and photon trapping, and reduced light reflectance after helium plasma exposure. The present technique consists of a simple maskless process that circumvents the use of chemical etching liquid, and utilizes soft ion bombardment on silicon substrate, keeping a good crystallinity.

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“…Black silicon is known as a side effect of many reactive ion etch processes (RIE). Some applications for this modification of silicon on wafer surfaces have come up in recent years, such as optical absorber elements [1], field emitters [2] and geometric enhancement of hydrophobic effects using the Lotus effect [3]. Other groups [4] use the appearance of black silicon as an indicator for process optimizations.…”

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confidence: 99%

Black silicon—new functionalities in microsystems

Stubenrauch¹,

Fischer²,

Kremin³

et al. 2006

J. Micromech. Microeng.

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Black silicon and its application as a new assembly method for silicon wafers at room temperature is presented. Needle-like structures on the surface after deep reactive ion etching with a length of 15–25 µm and 300–500 nm in diameter interlock with each other to form a bonding interface. After compression of two wafers at room temperature they generate retention forces up to 380 N cm−2 (3.8 MPa). If low contact forces are applied with partially interlocking of the needles, it is possible to generate a reversible Velcro®-like assembly. This new bonding process can be used for applications in the area of microfluidics with catalysts, microoptical or mechanical mountings or carrier wafer bonding in microelectronics.

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Control of shape of silicon needles fabricated by highly selective anisotropic dry etching

Cited by 18 publications

References 13 publications

A systematic approach to fabricate high aspect ratio silicon micro-needles for transdermal drug delivery

A systematic approach to fabricate high aspect ratio silicon micro-needles for transdermal drug delivery

Nanostructure formation on silicon surfaces by using low energy helium plasma exposure

Black silicon—new functionalities in microsystems

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