1,721,061 research outputs found
Nano-stereolithography process for precise and effective 2D and 3D nano/microfabrication
No full textSince it has emerged as a new technology, two-photon polymerization (TPP) initiated through the non-linear process of a two-photon absorption in a photosensitizer has been studied intensively in two- and three-dimensional (2D and 3D) microfabrications for various polymeric applications. For the fabrication of 2D nano-patterns, a nano-replication printing (nRP) process has been developed using a voxel matrix scanning method. In this method, a two-tone (black and white) bitmap figure is used as the designed pattern shape and is transformed into a voxel matrix in order to control the on/off of a focused laser beam. Complicated 3D microstructures can also be fabricated using layer-by-layer accumulation of the sliced multiple contour scanning data derived from the 3D CAD data. After the polymerization process, the unsolidified liquid-state resin is removed by pouring solvents, such as ethanol, onto the resin, and then the polymerized microstructures are developed. In previous works, 3D micro-optical components, micromechanical devices, and photonic crystals have been fabricated successfully with a high spatial resolution of approximately 100 nm. Recent efforts have also improved the efficiency and precision of TPP. This paper presents the microfabrication techniques based on TPP recently developed in our Department
Contour offset algorithm for precise patterning in two-photon polymerization
No full textA contour offset algorithm (COA) has been developed to fabricate precise patterns easily in the range of several microns using a nano-replication printing (nRP) process, which employs two-photon polymerization. In this process, microscale patterns are fabricated by a voxel matrix scanning method that uses raster graphic data transformed from the two-tone (black and white) bitmap figure file. The raster data consist of two kinds of entities to control laser on/off, '1' for laser-on and '0' for laser-off. However, the replicated patterns did not precisely coincide with an initial design due to an intrinsic shortage of the nRP process: the fabricated patterns become generally larger than the designed shape. To solve the point at issue, the COA was proposed in this work: an outer-contour matrix of an initial design was reconstructed then, it was modified by the amounts of offset-ratio that can be calculated using the relation of a pattern size, a designed figure size, and a voxel size. The effectiveness of the proposed algorithm was evaluated through several examples with 200 nm resolution. (c) 2005 Elsevier B.V. All rights reserved
Nano-Stereolithography Process for Fabrication of Three dimensional Nano/Micro-Devices/Objets
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Direct fabrication of micropatterns and three-dimensional structures using nanoreplication-printing (nRP) process
No full textA method for the direct fabrication of submicron-scale detailed patterns without the use of a photomask was developed by means of a nanoreplication-printing (nRP) process. Some patterns can be fabricated easily in the range of several microns inside a polymerizable resin by a scanning process using a volume-pixel (voxel) matrix that is transformed from a bitmap figure file. In the nRP process, liquid monomers are polymerized by the two-photon absorption (TPA) induced using a femtosecond pulse laser. Voxels are merged consecutively by overlapping in a range of several microns to fabricate various patterns, and the resolution of the process can be determined as the diffraction limit of the laser beam used to induce two-photon absorption polymerization (TPP). In this work, a beam expansion technique has been applied to enlarge the working area used to fabricate patterns. The establishment of a mechanism capable of the three-dimensional (3D) fabrication of microstructures by use of a lamination technique, which fabricates a structure layer by layer, has been attempted. The technique does not require the use of sacrificial layers or structures in 3D microstereolithography. Through this work, the usefulness of the nRP process is demonstrated by the fabrication of several patterns and 3D microstructures with a resolution of approximately 200 nm
Fabrication of nano-and micro-scale UV imprint stamp using diamond-like carbon coating technology
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Fabrication of microstructures using double contour scanning (DCS) method by two-photon polymerization
No full textA nano-stereolithography (NSL) apparatus has been developed for fabrication of microstructures with the resolution of 150 nanometers. In the NSL process, a complicated 3D structure can be fabricated by building layer by layer. so it does not require any sacrificial layer or any supporting structure. A laminated layer was fabricated by means of solidifying liquid-state monomers using two-photon absorption (TPA) which was induced by a femtosecond laser. When the fabrication of a 3D laminated structure was finished. unsolidified liquid-stage resins were removed to develop the fabricated structure by dropping several droplets of solvent. then the polymerized structure was only left on the glass substrate. A microstructure is fabricated by vector scanning method to save the fabrication time. The shell thickness of a structure is very thin within 200 nm, when it is fabricated by a single contour scanning (SCS) path. So, a fabricated structure can be deformed easily in the developing process. In this work, a double contour scanning (DCS) method was proposed to reinforce the strength of a shell typed structure. and a microcup was fabricated to show the usefulness of the developed NSL system and the DCS method
Fabrication of precise 3D metallic microstructures considering the heat effect by direct photoreduction process
No full textThree-dimensional SiCN ceramic microstructures via nano-stereolithography of inorganic polymer photoresists
No full textWe report a newly synthesized inorganic polymer photoresist with a high ceramic yield by the functionalization of polyvinyl-silazane (KiON VL20) with 2-isocyanatoethyl methacrylate via linkage or insertion reaction routes. The chemistry of the synthesis and the pyrolytic conversion as well as the mechanical evaluation were investigated by using various analytical instruments. We show for the first time that this photosensitive resin is a novel precursor for the fabrication of complex 3D SiCN ceramic microstructures with a 210 nm resolution via a two-photon absorbed crosslinking process and subsequent pyrolysis at 600 degrees C under a nitrogen atmosphere. Moreover, the dimensional deformation during pyrolysis was significantly reduced by adding silica nanoparticles as a filler. In particular, the ceramic microstructures containing 40 wt % silica nanoparticles exhibited a relatively isotropic shrinkage owing to its sliding free from the substrate during pyrolysis
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