Papers by Author: Takashi Mineta

Abstract: In order to realize a smart nano-machining and measurement system based on atomic force microscope (AFM), we have been developing diamond probes with a high-aspect-ratio, sharpened diamond tip. In this paper, we described the most important micromachining techniques for the fabrication of the diamond probes. The high-aspect-ratio diamond microstructures were successfully fabricated by employing our proposed two-step reactive ion etching (RIE) processes. A novel bonding technique of diamond to Si at wafer level was also developed by using an inorganic-organic hybrid sol-gel film (MeSiO_3/2) as an adhesive layer to prepare a diamond/SOI wafer as the starting material. Moreover, we demonstrated the applicability of a fabricated diamond probe not only to AFM measurements but also to a tool for nanomachining.

Abstract: For the purpose of an application for a blood vessel holding actuator of thrombus detector, evaporation technique and film properties of TiNiCu ternary shape memory alloy (SMA) thin film was studied. The SMA thin film was formed on a sacrificial Cu substrate by using a flash evaporation technique, with which very small TiNiCu alloy pellets were evaporated repeatedly. With this evaporation technique, phase transformation temperature of the deposited thin film can be controlled by deposition timing after the each pellet starts to vaporize. When the interval time before the deposition was 0s, the deposited thin film became a super elastic alloy (SEA), which starts to deform below the human body temperature of 37°C. On the other hand, when the interval time was 1s or longer, the deposited thin film shows a shape recovery temperature of about 60°C. Fracture strength of the thin film was obtained at least 170MPa, that corresponds to a fracture force of 570mN for holding actuator of 0.6mm in width and 6µm in thickness. Although the SEA film was fragile, the SMA film at the interval time of 5s was flexible enough to be bendable to small radius of 0.15mm.