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Basics of resist process are described including the practical techniques. The proximity patterning is cost-effective process having the potential realizing arbitrary 2-3μm width pattern. After explaining the standard processes and mechanisms, some issues in MEMS region is described.

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Sacrificial etching is a substantial step in MEMS or micromachining process, by which patterned thin films are partially released from the substrate surface to make mechanically movable micro structures. Amongst the variations of structural and sacrificial layer combinations including metal-over-polyimide and metal-over-polysilicon, we discuss the most fundamental processing technique of silicon oxide sacrificial release for the surface- and bulk-silicon micromachining, along with a toolbox to prevent the surface stiction problems.

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Dry etching process is one of the key technologies for manufacturing state-of-the-art devices both in LSI and MEMS fields. The importance of the process will be expanded in the future. In this paper, the technological history of silicon dry etching process has been reviewed from the viewpoint of demands and technical approach. The main demands, high through put, high etching anisotropy, high controllability are universal up to present date. The prospect for future trend is also exhibited.

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Over the past decades, the downscaling of transistor dimensions has improved circuit performance, power, and integration density. However, conventional device scaling is approaching the physical limits and it is increasingly difficult to sustain the same miniaturization scaling rate. Three-dimensional (3D) integrated circuits that stack multiple functional chips using through-silicon-vias (TSVs) and low-volume lead-free solder interconnects may overcome these problems, because this approach makes it possible to reduce global interconnect length and to increase device density without shrinking device dimensions. Different levels of 3D integration investigation were previously reported and updated. The current paper reviews the 3D integration technologies, including process technology and reliability characterization.

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In our laboratory, a nano-bio taste sensor based on carbon nanotubes has been developed. However, previous technique cannot separate elements such as CNT random network or electrode surface etc., because of sensor impedance change in fixed frequency. Electrochemical impedance spectroscopy (EIS) revealed CNT taste sensor with two R/C parallel circuits. Experimental complex plane plots were reproduced using a computer simulation program based upon the lumped equivalent circuit approach. It was found that the sensor has two relaxation times, and also that these circuits consist of two elements such as electrode surface and CNT random network.

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There exists a growing demand on high performance variable filters for multi-function, multi-band wireless systems used in wide variety of applications. A variable capacitor with high capacitance ratio (C_R) is one of the key devices to realize such controllable/reconfigurable filters. This paper reports the device structure, fabrication process, and the performance of a very high C_R variable capacitor using pure water as dielectric material. The device holds two reservoir cells and was fabricated by microelectromechanical systems (MEMS) technology. It exhibited three digitally-stepped capacitances; varied from 0.93 pF to 32.9 pF (C_R=35), then to 74.4 pF (C_R=80) at 1 MHz by filling each of the cells with pure water. In order to confirm the electrical behavior for such a fluid MEMS capacitor, its microwave performance was evaluated. An equivalent RF circuit model with 9 elements has been introduced and the device performance was successfully simulated up to 4 GHz. It is also confirmed that the 3 step capacitance values stay effective in the same frequency range.

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A novel packaging construction is newly proposed for the high-density packaging, and the three dimensional conductive pattern forming method on the vertical wall is developed and applied for the packaging. For this purpose, the spray coating and the angled exposure pattern forming technologies are examined to the vertical side wall of 600 μm height, and then the characteristics of the formed pattern are evaluated. As the result, the conductive patterns of 200 μm width and 300 μm spacing could be successfully formed on the vertical walls. The measured resistance of the pattern is within one ohm which is sufficient for the conductive wiring. The reliability of the chip package with the conductive pattern was also evaluated, and it was shown that the patterns formed by the proposed method satisfy the fundamental reliability characteristics.

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This paper proposes a sensing system for detecting bather's fall. The fall detection system uses ultrasound sensors installed on the ceiling of bathroom to measure the distance between sensor and a bather. The merits of utilizing ultrasound sensor are easy installation and easy use. Moreover the apparatus has an advantage of enhancing the privacy of bathers and having robustness against humidity. In order to detect bather's fall, the proposed system uses the following two methods: status detection and behavior detection. The function of status detection is to estimate bather's postures such as standing and sitting by monitoring the highest part of bather's body. Meanwhile, the function of behavior detection is to grasp the speed of bather's vertical movement by monitoring the change of distance between sensor and the bather. The system estimates the occurrence of bather's fall when the distance changes suddenly. As a result of experiment with some subjects, the system was possible to detect bather's falling behavior with high accuracy.

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We propose a liquid crystal (LC) lens with a new electrode structure of double circularly hole-patterned electrodes and external flat electrode for improving the optical properties such as a lens power and effective diameter with the optimum lens property. The lens power of the proposed LC lens is about 2.1 times as large as that of the previous LC lens with a single circularly hole-patterned electrode.

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