Abstract: In order to detect acoustic emission (AE) signals which are transient elastic waves generated by rapid release of strain energy derived from deformation in materials etc., general AE sensors were fabricated by using a piezoelectric film for detection of AE signals. However, these sensors required frequency domain analysis after recording AE signal. Therefore, this research has been developing an AE sensor integrated with cantilever array with different resonant frequencies for detection of AE signals divided into frequency domain by using MEMS techniques. In this paper, a design of cantilever structures was executed. Theoretical analysis and simulation using ANSYS software revealed that a resonant frequency of a cantilever was increased with decrease of its length in the range from 100 k to 1 MHz. Therefore, fabrication and frequency characterization of a cantilever array fabricated in our batch fabrication process were executed.
Abstract: Product designer is demanded to harmonize technical, economic, social, and environmental aspects of designing product. It is important for product designer to get the overview and the forecast of the property and the influence of the designing product by computer simulations. In order to support product designer and material designer, multi-scale product design and lifecycle simulation system is proposed. The multi-scale product design and lifecycle simulation system consists of multi-scale product design and simulation (MPDS) sub-system and product lifecycle simulation (PLS) sub-system. Concept of MPDS sub-system is an expansion of concept of current CAD/CAE system. Multi-scale products from micro/nano scale level to human scale level are designed continuously in the MPDS sub-system. Concept of PLS sub-system is an expansion of concept of current LCA system. PLS sub-system carries out product lifecycle simulation and evaluation of designing product. PLS sub-system is designed from the point of view of the interactions of subjects. The information of designing product is projected into PLS sub-system as a structured token including product information made by MPDS sub-system. Then, PLS sub-system carries out product lifecycle simulation.
Abstract: We have fabricated X-ray diffraction gratings for X-ray phase imaging using X-ray Talbot interferometer. In this paper, we propose the new low cost fabrication process using Si mold of Si dry etching and nano-imprint techniques. Si dry etching makes it possible to fabricate high aspect ratio rectangular microstructures. Therefore, this technique is expected to fabricate high precision grating pattern. In this paper, we propose the new low cost fabrication processes using Si mold of ICP-RIE and nano-imprint techniques. And, in order to form transparence imprint mold, we used thermal oxidation of Si mold. These demonstrations of thermal oxidation are promising method for high precision transparence imprint mold with low cost, and realized low cost optical device such as diffraction gratings.
Abstract: The resource saving of various electronic devices and advancement are demanded. Research and development of the MEMS device are briskly done from viewpoints of a miniaturization and highly-efficient. However, tip-shaped device manufacture is easy by the MEMS, but is hard to manufacture the tertiary structure. Therefore, as nanofabrication technology aiming at the mass production of the tertiary structure, LIGA process to make a microstructure body by copying it attracts attention of resin. In this research, the electric capacity type inclination sensor which used the LIGA process is produced. By using resin molding for a manufacturing step, a production cost can be low held down compared with the existing sensor. Former, the silicon mold which has a pattern of the size of 7×7 mm and structure height 100µm using ICP dry etching was produced. In addition, we performed resin molding using the silicon mold and succeeded in the manufacture and evaluation of the angle of inclination sensor. We expect that if techniques using resin-molded parts are introduced to the low-cost mass-production of MEMS devices (including sensors), the range of applications will further expand to new areas of technology and industry.
Abstract: We proposed a novel technique for self-assembly of micro parts by using DNA hybridization. As the demand for MEMS is growing, research on the self-assembly of micro parts is required to achieve fabrication of functional devices consisted of diverse micro parts. Our method has a unique characteristic where the selective assembly can be performed. At the targeted substrate region functionalized by single-stranded DNA, only components functionalized by the complementary one are assembled successfully. This is due to the complementary properties of DNA, which consists of four different bases (adenine (A), cytosine (C), guanine (G), and thymine (T)). A of one strand always pairs with a T of another, and so does C with G. The characteristic enables batch fabrication of diverse micro parts by using several kinds of DNA properly. Therefore, our method can be applied to the fabrication of MEMS. In this paper, in order to verify the feasibility of the automatic positioning using DNA hybridization, we performed a fundamental experiment for addressing polystyrene microspheres (1, 2, 6μm diameter) on the DNA patterned glass substrate.
Abstract: Deoxyribonucleic acid (DNA) has the appropriate molecular recognition property that makes it a suitable building block for the construction of nanoscale electronic devices. In particular, DNA employed as conducting wires is expected to be an alternative to optical lithography, which has resolution limits and requires high cost steppers. Nano-oxidation experiments were conducted on a silicon substrate by atomic force microscopy (AFM) to produce nanosized dots as anchors for DNA fixing. Short strand DNA molecules were then fixed on the anchors, which can recognize a specific complementary sequence. After the substrate was treated with a solution containing specific DNAs, which can hybridize with the short strand DNAs at the DNA sticky end, the anchors were connected to the DNAs by a self-assembly processes of DNA hybridization. Finally, silver was plated along the DNA molecules by a chemical treatment to introduce electrical conductivity. This method is expected to have potential for the integration of nanosized building blocks applicable to nanodevice construction.
Abstract: Micro plastic structures, typified by photoresists for semiconductor devices or various MEMS devices, photosensitive resins of microstereolithography, and so on, play one of the most important roles in the microdevices manufacturing. In order to process finer plastic structures with higher reliability for more complexly-modulated microdevices in the next generation micromanufacturing field, a nano removal processing method, which can be applied to a corrective machining process with the removal resolution less than 10nm in both lateral and vertical direction, is strongly required. In this study, we propose a novel nano removal processing method for micro plastic structures with photocatalyzed oxidation. Here, we apply photocatalysts micro particles as a specially designed material removal tool tip. Since a light energy is not directly used for processing the material, a material removal resolution does not depend on the diffraction limit. Further, using photocatalysts is free from micro tool wear problem. As the first report, in order to verify the fundamental feasibility of the proposed method, we performed basic experiments using TiO2 micro particles with the diameter of 500nm for cured photosensitive resin surface. An AFM observation of the processed surface showed that a vertical removal resolution of 8nm was achieved.
Abstract: The application of a neuron network to a bio/micro-sensor has potential as a drug screening device. In this study, micro-structures of surface-modified particles were applied to a scaffold for selective cell adhesion and growth. Silica particles were covered with a specific protein (fibronectin) or multi-walled carbon nanotubes (CNT) by electrostatic adsorption or transfer printing, respectively. They formed spatial patterns in a line-and-space structure tens of micrometers wide on a glass substrate. This paper investigates the effect of the coated material on the selectivity and adhesiveness of PC12 phenochromocytoma cells. An incubation process causes PC12 cells to autonomously align with selective adhesion on the micro-structures of both particles. The cells are minimally adhered to the glass surface around the particles. The structure of the fibronectin-coated particles enables a straight and uniform alignment of adhered cells, while that of bare silica particles causes randomly distributed cells. It was also found that the structure of CNT-adsorbed particles enhances cell adhesiveness to grow pseudopods of adhered cells.
Abstract: Recently, the authors have proposed a hybrid fabrication method of an ordered gold nano-dots array using a combination of the nano plastic forming and thermal annealing. In this study, in order to investigate morphology and optical properties of the gold nano-dots array fabricated by the proposed method, we develop a coupled three-dimensional simulation model by using the multi-phase-field method and the finite-difference-time-domain method. The simulation results demonstrate that the ordered gold nano-dots array which can be obtained by the proposed method exhibits quite characteristic optical responses due to the localized surface plasmon resonance.
Abstract: Three dimensional (3D) nano/quantum dot array structures have attracted more and more attention due to their broad applications. A new fabrication method of multilayer ordered nano dot array with low cost and high throughput is developed in this paper. This process is combination of Top-down and Bottom-up approaches: Nano Plastic Forming (NPF) patterning of metal layer coated on the substrate as Top-down approach and self-organization by dewetting as Bottom-up approach. Effects of process conditions on 3D nano-dot array formation are studied experimentally. Regularity and uniformity of first layer nano-dot array is transferred to the second layer nano-dots by optimizing thickness of the spacer layer and Au coating layer. Multilayer ordered nano dot array structures with good alignment are obtained by repeating coating and annealing processes.