We developed a fabrication process of narrow-gapped twin nano-tips for atomic force microscopy (AFM) dual probes. A tetrahedral dual tip consisting of an inclined crystalline Si (111) plane and two dry-etched vertical planes was fabricated using deep reactive ion etching (D-RIE) to form a (110)-oriented narrow trench, thermal oxidation and additively refilling the trench with resin to protect the sidewalls, mechanically polishing-back the top resin and SiO₂ layers to expose the Si (100) surface, and anisotropically etching the crystalline Si to form the (111) plane. The mechanically polished SiO₂ thin film and resin layer were used to protect the trench sidewalls thereby preventing the gap between the Si tips from widening because of oxidation. A dual tip with a 450 nm gap was obtained by using the fabrication process. In addition to protecting the Si sidewalls with a SiO₂ thin film, the resin refilling prevented abrasive particles from penetrating into the trench.

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Prototypes of optical microscanners using a pair of thermal microactuators have been designed, fabricated and evaluated. A micromirror with an area of 200×200µm is suspended by a pair of serpentine beams which are connected to a pair of thermal microactuators. The tilted angle of the mirror was simulated using FEM simulator Intelli Suite to optimize the beam parameters. The measured scan angle was about ±1.8°, which agreed reasonably well with the simulated results.

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We developed spalling technology of PZT thin film capacitors using the internal stress of the Ni film. We analyzed the normal stress of the PZT thin film capacitor using FEM and found that it ranges from 0.79 to 1.24 MPa by controlling the kind of the Ni film. The PZT thin film capacitor was successfully peeled from Si substrate when Ni-P alloy film was plated on it. It was also found that the peeled capacitor was not damaged during the peeling process by XRD analysis and electrical properties.

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This paper reports on a novel self-align fabrication process of narrow-gapped dual AFM (Atomic force microscopy) tip. The dual AFM tip was fabricated on (100) orientated Si substrate by using narrow trench etching, trench refilling with SOG (spin-on-glass), CMP (chemical-mechanical-polishing), and Si crystalline anisotropic etching. Through the process, a sharp dual AFM tip with a gap of 500 nm, which was defined by only the etched trench, width was successfully fabricated. Although other fabrication process using an acrylic-nitrile-styrene-epoxy resin refilling was also attempted, dual tip was not obtained due to the poor adhesion of the resin in silicon etching process. In addition, a dual AFM cantilever (Magneto-storictive film/Si 2.0 µm) was formed by MEMS fabrication process. The fabricated FePd 0.4 µm/Si 2.0 µm and Ni 1.3 µm/Si 2.0 µm cantilever were individually deflected to 1.4 µm at 300 Gauss and 0.4 µm at 240 Gauss due to effects of magnetic flux and negative-magneto-striction, respectively.

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In this paper, we report a micromachining of titanium using a desktop DRIE and fabrication of microstructure. We found out high speed exhaust characteristic is indispensable in the etching of titanium, and the etching rate more than 0.2 µm/min (a maximum rate is 0.4 µm/min) was provided in a small amount of etching gas (SF₆). As the demonstration of the method, we fabricated microneedles imitating mosquito's proboscis. We revealed that it is available for fabricating precision microstructure. Titanium has excellent mechanical property and corrosion resistance, and it is expected to be used as a material for MEMS. In this method, it is expected to apply to fabricate the three-dimensional structures.

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[in Japanese]

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