ProTEK PSB and ProTEK B3 (Brewer Science, Inc.) are negative type photosensitive resist and non-photosensitive resist for alkaline wet etching, respectively. This paper mainly reports the patterning characteristics, etch resistance and removal characteristics of ProTEK PSB under practical conditions for a real application. Our study found two problems of ProTEK PSB: unacceptably-large side-etching and difficulty in removing the primer by organic solvents or O₂ ashing. For the fabrication of a LSI-integrated tactile sensor, we used ProTEK PSB with a low temperature oxide underlayer. This combination solves both side etching problem for ProTEK PSB and pinhole problem for low temperature oxide, providing the practical alkaline etching mask which can be prepared at low temperature.

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Disk-type resonators employing in-plane resonant modes have a great impact on the application for high-sensitive mass sensing because of the high quality factor (Q) in atmospheric pressure. In this paper, we had fabricated disk-type resonators for two types of in-plane vibration modes with single crystal silicon (SCS), and the frequency properties were experimentally measured. Furthermore, modal analyses have been performed using finite element method for the structure model of the disk-type resonators under the conditions with different crystal orientations of SCS. We have examined the effects of the crystal orientation of SCS on the frequency properties of disk-type resonators for two types of vibration modes by the experimental and numerical analytical methods.

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We propose a method for detecting the frequency of a quartz crystal microbalance (QCM) with high resolution to realize an inexpensive and easy-expanding array sensor system. The principle of proposed method is measuring the difference of the resonant frequency of a reference QCM and the QCM with sensory film (sensor probe) with a resolution of 0.1-0.2 Hz installed in a sensor array. This frequency counter was realized as an LSI along with an oscillation circuit and a data-transfer unit. We prepared a sensor unit with up to eight QCM sensors and the LSI. For a sensory film, we used a polymer film that was deposited by RF sputtering of organic solids (synthetic polymer and biological material). We demonstrated the detection of ppb-level volatile compound using the developed frequency counter and QCM sensor array. Also, the sensor system comprising of plural-number of sensor units is shown.

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The through-hole electrode for the wafer level package (WLP) was formed with the aim of lowering the cost of infrared sensors. It has been difficult to plate a ZnS substrate for use as the window material of WLPs because of low adhesion. However, through-hole filling was successfully accomplished in this work by applying a newly developed method of direct nonelectrolyte plating. Concretely, a blast cleaning process was performed on a ZnS substrate of 1 mm thickness. Then, a through-hole with both sides tapered was formed with an aspect ratio of 7. A compound process of Cu substitution plating and Ni nonelectrolyte plating was applied to the through-hole, forming a uniform plating film with high adhesion in the hole. Finally, the through-hole was completely filled by Cu electroplating. A He leak test confirmed that the sample had high sealing properties, with a measured leak rate of 1.0 × 10^-10 Pa·m³/sec or less. The results showed that a ZnS substrate can be used effectively for IR window material, making it possible to reduce the cost of infrared cameras.

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In this paper, we report on a component modeling of in-plane 2DOF comb transducer for equivalent circuit analysis of electrostatic MEMS. The proposed model does not depend on connected components such as voltage sources, external forces, and springs since the model contained a dummy spring that can detect the comb displacement in itself. Using the model, we can analyze not only small-signal ac response but also dc operating points which means that once the parameters are calculated for a comb transducer, we need not to change the model parameters by changing any connected components. This model was adapted to a 2DOF SOI resonator and the measured frequency responses agreed well with the simulated responses.

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The specific optical characteristics which can be observed nanostructured optical device have great potentials for applying to several applications such as lifescience, optical communications, and data storage. Application of nanostrcutured optical device to industry, we suggest “printable photonics technology” for fabrication of nanostructured optical device based on nanoimprint lithography (NIL). In this study, using printable photonics technology, fabrication of flexible photonic crystal (PC) and its application for biosensor was performed. Using printable photonics technology-based PC for biosensing application, high sensitive detection of protein adsorption (detection limit: 1 pg/ml) could be detected.

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A needle-type water content sensor with a polyethersulfone (PES) polymer membrane was developed for the low-invasive, direct in-situ measurement of plant water content (PWC) in prior work. In this paper we demonstrate a measurement of plant water stress that represents the demand for water of the plant and greatly affects its sweetness. We inserted the sensor into a stalk of strawberry (Fragaria×ananassa) and soil. The variation in both the plant and the soil water content were successfully detected, which revealed the delay between variation in the plant water stress and soil water content after irrigation. Such delay could only be detected by the proposed sensor that could directly measure the variation of PWC in situ and continuously. The experiments also showed the variation in the signals as a function of detection sites and suggested that the detection sites of plant water stress need to be considered when the sensor is applied to irrigation culture.

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