Fabrication of three-dimensional microstructure using maskless gray-scale lithography

Totsu, Kentaro; Fujishiro, Kenta; Tanaka, Shuji; Esashi, Masayoshi

doi:10.1016/j.sna.2005.12.008

Cited by 146 publications

(79 citation statements)

References 14 publications

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“…Figure 5c shows the relation between the volume ratio and the focal length of the prepared lenses ( Figure 4 and Figure S2), as calculated by Equation (1). In BY11-030 lenses, the focal length increased from 88 to 117 µm when the volume ratio Q m /Q s increased from 1/2 to 4/1.…”

Section: Photofabrication Of Biconvex Polymer Lenses and Control Of Tmentioning

confidence: 95%

“…A variety of methods, which can be divided into moldless or mold-assisted techniques, have been reported for fabricating microlenses and microlens arrays. Concerning moldless techniques, grayscale photolithography [1], thermal reflow [2], laser micromachining [3][4][5], inkjet printing [6], microcontact printing [7], and self-assembly [8,9] have been proposed to fabricate various polymeric, glass, silicon, and ceramic microlens arrays. However, many of these methods require sophisticated machinery, such as photo-or electron-beam lithography systems and lasers, thus, greatly limiting the high-throughput and low-cost aspects of the production of such microlenses.…”

Section: Introductionmentioning

confidence: 99%

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Biconvex Polymer Microlenses with Tunable Imaging Properties Designed by Janus Droplet Microfluidics

2015

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This work presents a technique for fabricating biconvex polymer microlenses using microfluidics, and then evaluates their tunable optical properties. A glass microfluidic channel was employed to rapidly mass-produce nanoliter-sized biphasic Janus droplets, which consist of a biconvex segment of a photocurable monomer and a concave-convex segment of a non-curable silicone oil that contained a surfactant. Subsequent photopolymerization produces polymeric biconvex spherical microlenses with templated dual curvatures. By changing the flow-rate ratios of the photocurable and non-curable droplet phases in the microfluidic channel, the radii of curvature of the two lens surfaces and the thicknesses of the resultant microlenses can be varied. The resulting biconvex microlenses with different shapes were used in image projection experiments. Different magnification properties were observed, and were consistent with the properties estimated quantitatively from the geometrical parameters of the lenses.

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Section: Photofabrication Of Biconvex Polymer Lenses and Control Of Tmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Biconvex Polymer Microlenses with Tunable Imaging Properties Designed by Janus Droplet Microfluidics

2015

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“…In general, 3-D micro/nanostructures, including 3-D NIL molds, can be fabricated using various techniques such as multistep lithography , maskless gray-scale lithography (Totsu et al 2006), FIB writing (Taniguchi et al 2006), proton beam writing (Simcic et al 2005) , xray lithography (Romanato et al 2003); (Romanato et al 2004) , or combination of EBL and dry etching. These techniques are high cost, low throughputs and some suitable only for relatively large features and not for nanoscale applications.…”

Section: Research Backgroundmentioning

confidence: 99%

Three-Dimensional Patterning Using Ultraviolet Nanoimprint Lithography

Alkaisi¹,

Mohamed²

2010

Lithography

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“…The sample is rotated on a computer-controlled tilt stage, which controls the sidewall angle. Electron-beam [20][21][22] and ultraviolet [23] photo lithography utilize maskless exposure systems to deliver a programmed dose pattern to the photoresist. As each spot exposes the photoresist, the beam write time or exposure intensity is adjusted to control the dose and achieve variable-relief structures.…”

Section: Direct-write Photolithographymentioning

confidence: 99%

Double-Exposure Grayscale Photolithography

Mosher

Waits

Morgan

et al. 2009

J. Microelectromech. Syst.

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Three-dimensional (3D) photoresist structures may be realized by controlling the transmitted UV light intensity in a process termed gray-scale photolithography.Light modulation is accomplished by diffraction through sub-resolution pixels on a photomask. The number of photoresist levels is determined by the number of different pixel sizes on the mask, which is restricted by mask fabrication. This drawback prevents the use of gray-scale photolithography for applications that need a high vertical resolution.The double-exposure gray-scale photolithography technique was developed to improve the vertical resolution without increasing the number of pixel sizes. This is achieved by using two gray-scale exposures prior to development. The resulting overlay produces an exposure dose that is a combination of both exposures.Calibration is utilized to relate the pixel sizes and exposure times to the photoresist height. This calibration enables automated mask design for arbitrary 3D structures and investigation of other effects, such as misalignment between the exposures.

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Fabrication of three-dimensional microstructure using maskless gray-scale lithography

Cited by 146 publications

References 14 publications

Biconvex Polymer Microlenses with Tunable Imaging Properties Designed by Janus Droplet Microfluidics

Biconvex Polymer Microlenses with Tunable Imaging Properties Designed by Janus Droplet Microfluidics

Three-Dimensional Patterning Using Ultraviolet Nanoimprint Lithography

Double-Exposure Grayscale Photolithography

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