Polydimethyl siloxane wet etching for three dimensional fabrication of microneedle array and high-aspect-ratio micropillars

Three-dimensional interconnected nanoporous structure (3-D INPOS) possesses high aspect ratio, large surface area, as well as good structural stability. Profiting from its unique interconnected architecture, the 3-D INPOS pseudocapacitor achieves a largely enhanced capacitance and rate capability.

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Self-ordered nanospike porous alumina fabricated under a new regime by an anodizing process in alkaline media

Scientific Reports ◽

10.1038/s41598-021-86696-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Mana Iwai ◽

Tatsuya Kikuchi ◽

Ryosuke O. Suzuki

Keyword(s):

Aspect Ratio ◽

High Aspect Ratio ◽

Porous Alumina ◽

Three Dimensional ◽

Alkaline Media ◽

Alkaline Electrolyte ◽

Subsequent Formation ◽

Interpore Distance ◽

Wide Range ◽

Ordered Porous

AbstractHigh-aspect ratio ordered nanomaterial arrays exhibit several unique physicochemical and optical properties. Porous anodic aluminum oxide (AAO) is one of the most typical ordered porous structures and can be easily fabricated by applying an electrochemical anodizing process to Al. However, the dimensional and structural controllability of conventional porous AAOs is limited to a narrow range because there are only a few electrolytes that work in this process. Here, we provide a novel anodizing method using an alkaline electrolyte, sodium tetraborate (Na2B4O7), for the fabrication of a high-aspect ratio, self-ordered nanospike porous AAO structure. This self-ordered porous AAO structure possesses a wide range of the interpore distance under a new anodizing regime, and highly ordered porous AAO structures can be fabricated using pre-nanotexturing of Al. The vertical pore walls of porous AAOs have unique nanospikes measuring several tens of nanometers in periodicity, and we demonstrate that AAO can be used as a template for the fabrication of nanomaterials with a large surface area. We also reveal that stable anodizing without the occurrence of oxide burning and the subsequent formation of uniform self-ordered AAO structures can be achieved on complicated three-dimensional substrates.

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High-aspect-ratio structure formation techniques for three-dimensional metal-oxide-semiconductor transistors

Microelectronic Engineering ◽

10.1016/j.mee.2006.01.270 ◽

2006 ◽

Vol 83 (4-9) ◽

pp. 1740-1744 ◽

Cited By ~ 1

Author(s):

Hideo Sunami ◽

Shunpei Matsumura ◽

Koji Yoshikawa ◽

Kiyoshi Okuyama

Keyword(s):

Aspect Ratio ◽

Metal Oxide ◽

Structure Formation ◽

High Aspect Ratio ◽

Three Dimensional ◽

Metal Oxide Semiconductor ◽

Oxide Semiconductor ◽

High Aspect Ratio Structure

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High-Aspect-Ratio Copper Via Filling Used for Three-Dimensional Chip Stacking

Journal of The Electrochemical Society ◽

10.1149/1.1572154 ◽

2003 ◽

Vol 150 (6) ◽

pp. G355 ◽

Cited By ~ 111

Author(s):

Jian-Jun Sun ◽

Kazuo Kondo ◽

Takuji Okamura ◽

SeungJin Oh ◽

Manabu Tomisaka ◽

...

Keyword(s):

Aspect Ratio ◽

High Aspect Ratio ◽

Three Dimensional

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Topology Optimization of Micromachined Structures With the Manufacturing Constraints of KOH Etching of (110) Silicon

Volume 4: 20th International Conference on Design Theory and Methodology; Second International Conference on Micro- and Nanosystems ◽

10.1115/detc2008-49617 ◽

2008 ◽

Author(s):

Sudarshan Hegde ◽

G. K. Ananthasuresh

Keyword(s):

Topology Optimization ◽

Aspect Ratio ◽

High Aspect Ratio ◽

Cost Effective ◽

Wet Etching ◽

Minimum Length ◽

The Cost ◽

Design Parameterization ◽

Koh Etching ◽

Si Wafer

The focus of this paper is on designing useful compliant micro-mechanisms of high-aspect-ratio which can be microfabricated by the cost-effective wet etching of (110) orientation silicon (Si) wafers. Wet etching of (110) Si imposes constraints on the geometry of the realized mechanisms because it allows only etch-through in the form of slots parallel to the wafer’s flat with a certain minimum length. In this paper, we incorporate this constraint in the topology optimization and obtain compliant designs that meet the specifications on the desired motion for given input forces. Using this design technique and wet etching, we show that we can realize high-aspect-ratio compliant micro-mechanisms. For a (110) Si wafer of 250 μm thickness, the minimum length of the etch opening to get a slot is found to be 866 μm. The minimum achievable width of the slot is limited by the resolution of the lithography process and this can be a very small value. This is studied by conducting trials with different mask layouts on a (110) Si wafer. These constraints are taken care of by using a suitable design parameterization rather than by imposing the constraints explicitly. Topology optimization, as is well known, gives designs using only the essential design specifications. In this work, we show that our technique also gives manufacturable mechanism designs along with lithography mask layouts. Some designs obtained are transferred to lithography masks and mechanisms are fabricated on (110) Si wafers.

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Strong and Reversible Adhesion of Interlocked 3D-Microarchitectures

Coatings ◽

10.3390/coatings9010048 ◽

2019 ◽

Vol 9 (1) ◽

pp. 48 ◽

Cited By ~ 1

Author(s):

Minho Seong ◽

Hyun-Ha Park ◽

Insol Hwang ◽

Hoon Eui Jeong

Keyword(s):

Aspect Ratio ◽

Structural Stability ◽

High Aspect Ratio ◽

Three Dimensional ◽

Normal Direction ◽

One Dimensional ◽

Reversible Adhesion ◽

Adhesion Behavior ◽

Organic Nanomaterials ◽

Good Agreement

Diverse physical interlocking devices have recently been developed based on one-dimensional (1D), high-aspect-ratio inorganic and organic nanomaterials. Although these 1D nanomaterial-based interlocking devices can provide reliable and repeatable shear adhesion, their adhesion in the normal direction is typically very weak. In addition, the high-aspect-ratio, slender structures are mechanically less durable. In this study, we demonstrate a highly flexible and robust interlocking system that exhibits strong and reversible adhesion based on physical interlocking between three-dimensional (3D) microscale architectures. The 3D microstructures have protruding tips on their cylindrical stems, which enable tight mechanical binding between the microstructures. Based on the unique 3D architectures, the interlocking adhesives exhibit remarkable adhesion strengths in both the normal and shear directions. In addition, their adhesion is highly reversible due to the robust mechanical and structural stability of the microstructures. An analytical model is proposed to explain the measured adhesion behavior, which is in good agreement with the experimental results.

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