We have investigated a novel debris-free high speed laser dicing technology for MEMS. The target were a Tempax or Pyrex glass and silicon and their anodically-bonded multi-layered wafers. Our technology combines three processes: dicing guide fabrication, wafer separation process, and a tape expansion. First process was the internal transformation using a nanosecond Nd:YVO₄ laser. The laser pulse width and repetition rate was 11 ns and 20∼100 kHz. The laser scanning speed was over 100 mm/sec. The second process was a mechanical bending separation. The bending stress for glass and Si wafer separation was 10 and 100 MPa, respectively. At the third step, spaces between chips were opened by the tape expansion. The internal transformation fabricated in the first process worked well as the guide of the separation. The diced lines completely followed the internal transformation.

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This paper presents design, fabrication and evaluation of a polydimethylsiloxane (PDMS) —glass microfluidic device for quantitative determination of manganese ion (Mn(II)) in oceanic environments. The microfluidic device can perform luminol-hydrogen peroxide chemiluminescence (CL) reaction in a flow-through manner for highly sensitive Mn (II) quantification. A chelate resin column was integrated in the microfluidic device for removal of coexisting metal ion such as Fe(II). The developed device could quantify Mn(II) in nM level under coexistence of μM level of Fe(II). The microfluidic device developed here will be used as a core element of a totally integrated in situ chemical analyzer that we have been developing for oceanography applications.

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An integrated in situ analyzer for microbial ATP (IISA-ATP) has been developed with a microfluidic device as its core component to realize a compact and fully integrated system. In the system, a bioluminescence (luciferin—luciferase) reaction is conducted for ATP quantification. The microfluidic device has a coil-shaped microchannel for highly sensitive photo intensity measurement. In this paper, the concept of the IISA-ATP and optimization of the microchannel design to enhance sensitivity are presented. As a result of the optimization, linear correlation of the luminescence intensity with the ATP concentration in the range of 2 to 2 × 10⁴ pM was achieved.

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GaN-based light emitting diode (LED) structure (n-GaN/quantum wells/p-GaN) was grown by molecular beam epitaxy (MBE) on a GaN-on-Si template substrate grown by metal organic chemical vapor deposition (MOCVD). The GaN crystal grew continuously on the template and surface of the GaN film was flat. We fabricated very thin comb-shaped electrodes on the GaN film as semi-transparent metal contacts. Blue light emission was observed from the semi-transparent electrode region on p-GaN crystal at peak wavelength of 410nm at room temperature. On the other hand, we propose a light distribution variable device which changes the light direction emitted from LEDs by integration of GaN-based LEDs and Si micromachining technology. To demonstrate the light distribution variable device, we fabricated micro stage from the template substrate as preliminary experiment for the light distribution variable device. The device was successfully fabricated and we observed that the stage moved about 40 μm at the voltage of 100 V. These values are almost same as calculated values. Photoluminescence (PL) was also observed in this device. The electric wiring has not been completed, these results demonstrate the usefulness of monolithic fabrication of GaN-Si hybrid MEMS.

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Recently, a soft actuator was developed using an electro conducting polymer and an ionic conducting polymer. Moreover, the stereolithography that uses femto second laser was researched as a method of multi-photon sensitized polymerization. In this proposal, we confirmed the fabrication of a 3D microstructure using a electro conducting polymer with a femto second laser, and its operation as an actuator. The diameter of the actuator core was 3.5μm, and its height was 12μm.

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In this paper, we studied a possibility of a taste sensing using a quartz crystal microbalance (hereafter cited as QCM) sensor. We modified oleic acid film to Au electrode of the quartz resonator by an electrodeposition method. The electrodeposition film was used as the adsorber for taste substances. We consider that oscillation frequency decreases with the mass changes due to adsorption. Frequency characteristics differed in each basic taste solution. Their characteristics were based on chemical nature of taste substances. Ions or organic molecules were attached to electrodeposition film by electrostatic interaction or hydrophobic interaction respectively. Moreover, we studied the taste evaluation of sweetness solutions and sourness solutions. As a result, in case of sweetness solutions, the frequency changes correlated with Brix (%) (r = -0.98). In case of sourness solutions, especially, the frequency changes correlated in pH (r = 0.89) of organic acids. Differences of the frequency changes depended on the amount of undissociated molecule in the acid solutions. Additionally, taste evaluation by the QCM sensor related to gustatory sense of human. Therefore, we suggested the validity of the QCM sensor for evaluation of the taste solutions.

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