Integrated vertical screen microfilter system using inclined SU-8 structures

Yoon, Yong-Kyu; Park, Jung Hwan; Cros, F.; Allen, Mark G.

doi:10.1109/memsys.2003.1189727

Cited by 31 publications

(9 citation statements)

References 7 publications

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“…In-plane microneedles are fabricated by using inclined UV lithography and nickel-electroforming, as illustrated in UV lithography [21][22][23]. In this step, the SU-8 layer should be thicker than the desired height of the in-plane microneedle.…”

Section: In-plane Microneedlementioning

confidence: 99%

A novel fabrication process for out-of-plane microneedle sheets of biocompatible polymer

Han

Hyun²,

Park

et al. 2007

J. Micromech. Microeng.

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This paper presents a novel process for fabricating out-of-plane microneedle sheets of biocompatible polymer using in-plane microneedles. This process comprises four steps: (1) fabrication of in-plane microneedles using inclined UV lithography and electroforming, (2) conversion of the in-plane microneedles to an out-of-plane microneedle array, (3) fabrication of a negative PDMS mold and (4) fabrication of out-of-plane microneedle sheets of biocompatible polymer by hot embossing. The in-plane microneedles are fabricated with a sharp tip for low insertion forces and are made long to ensure sufficient penetration depth. The in-plane microneedles are converted into an out-of-plane microneedle array to increase the needle density. The negative mold is fabricated for mass-production using a polymer molding technique. The final out-of-plane microneedle sheets are produced using polycarbonate for biocompatibility by employing the hot embossing process. The height of the fabricated needles ranges from 500 to 1500 µm, and the distance between the needles is 500 to 2000 µm. The radii of curvature are approximately 2 µm, while the tip angles are in the range of 39-56 • . Most of the geometrical characteristics of the out-of-plane microneedles can be freely controlled for real life applications such as drug delivery, cosmetic delivery and mesotherapy. Since it is also possible to mass-produce the microneedles, this novel process holds sufficient potential for applications in industrial fields.

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Section: In-plane Microneedlementioning

confidence: 99%

A novel fabrication process for out-of-plane microneedle sheets of biocompatible polymer

Han

Hyun²,

Park

et al. 2007

J. Micromech. Microeng.

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“…Mini/microchannels with integrated micro-pillars offer enhanced heat and mass transfer coefficients, surface-area-tovolume ratio, and thermal conductance in comparison with plain microchannels. Thus, they have been used for an array of applications such as microreactors [1,2], micro heat exchangers [3][4][5], micro-total analysis systems (μTAS) [6], micropumping [7,8], and microfilters [9]. However, the integrated micro-pillars increase the shear force exerted to the passing fluid which results in a pressure drop augmentation.…”

Section: Introductionmentioning

confidence: 99%

Creeping Flow Through Microchannels With Integrated Micro-Pillars

Tamayol

Gunda

Akbari

et al. 2012

ASME 2012 10th International Conference on Nanochannels, Microchannels, and Minichannels

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Pressure drop through micro-pillar-integrated mini/microchannels is studied experimentally and analytically. Following our previous studies, the low aspect ratio micropillars embedded in a microchannel are modeled as a porous medium sandwiched between channel walls. The pressure drop is expressed as a function of the salient geometrical parameters such as channel dimension, diameter and spacing between the adjacent cylinders as well as their arrangement. To verify the developed model, several silicon/glass samples with and without integrated pillars are fabricated using the deep reacting ion etching (DRIE) technique. Pressure drop measurements are performed over a range of water flow rates ranging from 0.1 ml/min to 0.5 ml/min. The proposed model is successfully verified with the present experimental data. A parametric study is performed by employing the proposed model, which shows that the flow resistance has a reverse relationship with the micro-pillar diameter and the mini/microchannel porosity. In addition, staggered arrangements have a significantly lower flow resistance than squared arrays of pillars especially in dense structures.

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“…UV lithography is currently widely used in optoelectronics, semiconductors and micro-electromechanical system processes, and is much less expensive than x-ray or e-beam lithography (laser optical system) [1][2][3]. It was not until the 1990s, however, that UV lithography was used to fabricate high aspect ratio microstructures with SU-8 photoresists [4][5][6]. Han et al [7] explored the use of the inclined exposure method to fabricate microstructures using SU-8 photoresists, and presented the results of using square, triangular and rectangular patterned masks in lithography with SU-8 photoresists.…”

Section: Introductionmentioning

confidence: 99%

The application of Fresnel equations and anti-reflection technology to improve inclined exposure interface reflection and develop a key component needed for Blu-ray DVD–micro-mirrors

Hung

Liao

2008

J. Micromech. Microeng.

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The goal of this paper is to explore the use of inclined exposure technology to fabricate millimeter-grade thick film polymer optical microstructures on glass substrates and to resolve the partial reflection of optical energy at interfaces that causes the structural problem of unnecessary photo cross-linking, which can affect the structural shape. This paper uses inclined exposure technology to cause UV illumination to impinge on the substrate at a certain non-perpendicular angle and fabricate a three-dimensional optical-grade micro-mirror as part of an effort to develop an integrated, miniature Blu-ray optical pickup head. Although a transparent glass substrate was employed in the experiment, the system included mask glass (n m = 1.53), glass substrate (n g = 1.5) and photopolymerized polymer (n p = 1.67). UV light tends to undergo partial reflection at the interfaces due to the materials' different refractive indices. This optical phenomenon is particularly severe at higher exposure energies (∼14 000 mJ cm −2 ) in the fabrication of millimeter-grade thick films. The Fresnel equations are used to calculate that the maximum interface reflection of optical energy is approximately 1.5%. This paper therefore selects a medium with a matching refractive index (n gl = 1.473) and removable anti-reflection technology in order to resolve the interface reflection problem, and applies this solution to 45 • micro-mirror manufacturing technology, enabling a surface roughness of approximately 20 nm (λ/20, λ = 405 nm) as measured by WYKO.

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Integrated vertical screen microfilter system using inclined SU-8 structures

Cited by 31 publications

References 7 publications

A novel fabrication process for out-of-plane microneedle sheets of biocompatible polymer

A novel fabrication process for out-of-plane microneedle sheets of biocompatible polymer

Creeping Flow Through Microchannels With Integrated Micro-Pillars

The application of Fresnel equations and anti-reflection technology to improve inclined exposure interface reflection and develop a key component needed for Blu-ray DVD–micro-mirrors

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