scholarly journals Numerical Analysis and Experimental Study on Fabrication of High Aspect Ratio Tapered Ultrafine Holes by Over-Growth Electroforming Process

Micromachines ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 824
Author(s):  
Yunyan Zhang ◽  
Pingmei Ming ◽  
Runqing Li ◽  
Ge Qin ◽  
Xinmin Zhang ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Structural Parameters ◽  
Geometric Shape ◽  
High Tech ◽  
Shape Evolution ◽  
Metallic Plate ◽  
Electroforming Process ◽  
Photoresist Film ◽  
The Relationship

High aspect ratio (HAR) ultrafine tapered holes (diameter ≤5 μm; AR ≥5) are the most important elements for some high-tech perforated metallic products, but they are very difficult to manufacture. Therefore, this paper proposes a nontraditional over-growth electroforming process. The formation mechanism of the HAR ultrafine tapered holes is investigated, and the factors controlling the geometric shape evolution are analyzed numerically. It was found that the geometric shape and dimensions of the holes are highly dependent on the diameter and thickness of the photoresist film patterns, but are hardly affected by the spacing between two neighboring patterns; the achievable diameter for a given hole depth becomes small with the increasing pattern diameter, but it becomes big with the increasing pattern thickness. These correlations can be well interpreted by the established two empirical equations that characterize the relationship between the minimum orifice of the tapered hole and the structural parameters of the photoresist film patterns previously formed on the substrate. Application of the fabricated 1500 tapered holes with 3-μm diameter and 17-AR as the nozzles of the medical precision nebulizer is also examined. The studies show that the over-growth electroforming process is highly applicable in fabricating the perforated metallic plate with HAR ultrafine tapered holes.

Shape evolution of high aspect ratio holes on Si(001) during hydrogen annealing

2013 ◽  
Vol 114 (18) ◽  
pp. 183512 ◽  
Author(s):  
K. Sudoh ◽  
R. Hiruta ◽  
H. Kuribayashi
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Shape Evolution ◽  
Hydrogen Annealing

scholarly journals Titanium dioxide high aspect ratio nanoparticle hydrothermal synthesis optimization

2015 ◽  
Vol 13 (1) ◽  
Author(s):  
Paulina Półrolniczak ◽  
Mariusz Walkowiak
Keyword(s):  
Titanium Dioxide ◽  
Hydrothermal Synthesis ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Reaction Conditions ◽  
Practical Guidelines ◽  
Nanowire Synthesis ◽  
The Relationship

AbstractTiOThe relationship between reaction conditions and morphology is discussed and practical guidelines for titanium dioxide nanowire synthesis are suggested

Fabrication of Large-Area Imprint Mold with High-Aspect-Ratio Nanotip Arrays of Sub-Micron Diameter

2007 ◽  
Vol 364-366 ◽  
pp. 607-612 ◽  
Author(s):  
Chia Jen Ting ◽  
Hung Yin Tsai ◽  
Chang Pin Chou
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Electron Cyclotron Resonance ◽  
Plasma Process ◽  
Large Area ◽  
Ecr Plasma ◽  
Aspect Ratios ◽  
Electroforming Process ◽  
Micron Diameter ◽  
Short Time

Many research works have been focusing on nanoimprint technology due to the recent potential mass production for the nanostructure applications. For optical or display application, a nanoimprint mold of large area becomes one of the thorniest techniques since it takes much time to fabricate the whole mold with nanostructure and it may make the beginning nanostructures inconsistent with the final ones. In order to fabricate the nanostructure mold of large area in a short time, the plasma process forming nanostructures on silicon substrate and the electroforming process are explored in the current study. Well-aligned nanotip arrays of 4 inch silicon were fabricated by electron cyclotron resonance (ECR) plasma process using gas mixtures of silane, methane, argon, and hydrogen. The resultant tips have nano-scale apexes, approximately ~1 nm, with high aspect ratios, nearly ~15, which were achieved by simultaneous SiC nano-mask formation and dry etching during ECR plasma process. Next, the nickel mold of nanostructures is made from silicon nanostructures through the electroforming process by using Nickel Sulfamate. The total thickness of the nickel mold is 120 μm after a 10-hour-long electroforming process. The nanostructures of 100 nm diameter holes are successfully obtained. Nanoimprint process is proceeded by the nickel mold and the reflectance of the PMMA after imprinting at 160 °C has the lowest value, 0.2 %, compared with the other results for the incident optical wavelength of 550 nm. The large-area imprint mold with high-aspect-ratio nanotip arrays of sub-micron diameter is fabricated and is proofed by the optical application.

scholarly journals Microfabrication of Ni-Fe Mold Insert via Hard X-ray Lithography and Electroforming Process

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 486
Author(s):  
Jae Man Park ◽  
Sung Cheol Park ◽  
Da Seul Shin ◽  
Jong Hyun Kim ◽  
Hanlyun Cho ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Mold Insert ◽  
Positive Type ◽  
X Ray ◽  
Electroforming Process ◽  
Pattern Size ◽  
Efficient Replication ◽  
Gold Thickness ◽  
Exposure Energy

In this research, a Ni-Fe mold insert for the efficient replication of high aspect-ratio microstructure arrays was fabricated via hard X-ray lithography and an electroforming process. For the X-ray exposure on a photoresist, a gold-based X-ray mask was prepared with conventional UV photolithography. The gold thickness was designed to be over 15 μm to prevent development underneath the absorber and to enhance the adhesion strength between the photoresist and substrate. By using the X-ray mask, a positive-type photoresist was selectively exposed to X-ray under an exposure energy of 4 kJ/cm3. Thereafter, the exposed region was developed in a downward direction to effectively remove the residual photoresist from the substrate. During the evaporation process, deionized water mixed with a surface additive prevented the bending and clustering of the photoresist microstructure arrays by lowering the capillary force, resulting in a defect-free mother structure for electroforming. Lastly, the mother structure was uniformly Ni-Fe electroformed on a conductive substrate without the formation of any pores or detachment from the substrate. Based on the proposed microfabrication process, a Ni-Fe mold insert with a 183 μm pattern size, 68 μm gap size, 550 μm height, 2116 microcavities and a hardness of 585 Hv was precisely manufactured. It can be utilized for the mass production of high aspect ratio metal and ceramic microstructure arrays in micro molding technologies.

Fabrication and Testing of High Aspect Ratio Metal Micro-Gas Chromatograph Columns

2004 ◽  
Author(s):  
Abhinav Bhushan ◽  
Dawit Yemane ◽  
Jost Goettert ◽  
Edward B. Overton ◽  
Michael C. Murphy
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Gas Chromatograph ◽  
X Ray ◽  
Tubular Columns ◽  
Sensor Performance ◽  
Head Pressure ◽  
Separation Columns ◽  
The Relationship ◽  
Rectangular Columns

Micro gas chromatograph (GC) separation columns were fabricated and tested. Rectangular columns with high aspect ratio have inherent benefits over traditional tubular columns and can easily be integrated into a GC sensor system for rapid chromatographic analysis. The 2 m long, 50 μm wide, 500 μm tall columns were fabricated out of electroplated nickel through deep X-ray lithography using the LIGA technique. Critical fabrication issues including reproducible fabrication of compact footprint, deep columns and sealing of the metal columns were addressed. Experiments were conducted to establish the relationship between column head pressure and flow rate. Methane samples analyzed using hydrogen as a carrier gas on uncoated columns showed very little dispersion suggesting that there was no internal leakage in the columns. The sensor performance data compares well with other micro GC sensor systems.

Fabrication of High Aspect Ratio Periodical Structure on Metal Using an Electroforming Process

2007 ◽  
Vol 364-366 ◽  
pp. 280-283
Author(s):  
Wei Ching Chuang ◽  
Ching Kong Chao ◽  
Wen Chung Chang ◽  
Chi Ting Ho
Keyword(s):  
Thin Film ◽  
Aspect Ratio ◽  
Periodic Structure ◽  
High Aspect Ratio ◽  
Holographic Interferometry ◽  
Positive Photoresist ◽  
Nickel Cobalt ◽  
Periodical Structure ◽  
Photoresist Film ◽  
Initial Results

A procedure for fabricating a periodic structure on a metal at submicron order using holographic interferometry and molding processes is described. First, holographic interference using a He-Cd (325nm) laser is used to create the master of the periodic line structure on an i-line sub-micron positive photoresist film. A 200nm nickel thin film is then sputtered onto the positive photoresist. Pattern is then transferred to a metal using Nickel-Cobalt electroforming. Initial results show the technique can accurately control the grating’s period and depth.

scholarly journals Modeling and analysis of high aspect ratio wing considering random structural parameters

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bangsheng Fu ◽  
Ya Yang ◽  
Hui Qi ◽  
Jiangtao Xu ◽  
Shaobo Wang
Keyword(s):  
Elastic Modulus ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Structural Parameters ◽  
Torsional Stiffness ◽  
Statistical Characteristics ◽  
Modeling And Analysis ◽  
One Dimensional ◽  
Advanced Composite Materials ◽  
Aeroelastic Model

AbstractWith the application of advanced composite materials in High-Aspect-Ratio wings (HARW), the randomness of structural parameters, such as elastic modulus and Poisson's ratio, is enhanced. Hence, in order to explore the whole picture of aeroelastic problems, it is of great significance to study the role of random structural parameters in aeroelastic problems. In this paper, the dynamic response of flexible HARW considering random structural parameters is analyzed. An aeroelastic model of a one-dimensional cantilevered Euler–Bernoulli beam considering aerodynamic forces acting on the wing is established based on Hamilton's principle. Adopted the idea of simplifying calculation, the effect of random structural parameters is analyzed. Then, considering the elastic modulus and torsional stiffness as continuously one-dimensional random field functions, and discretized by local method. The first and second order recursive stochastic nonlinear finite element equations of wing are derived by using perturbation method. Based on it, statistical expression of aeroelastic effects of the wing is derived. Monte Carlo method is adopted to verify the effectiveness of the method. Numerical simulations indicate that the method proposed can well mirror the statistical characteristics of aeroelastic response.

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