Motoki Terano

Nanometer-level high-accuracy molding using a photo-curable silicone elastomer by suppressing thermal shrinkage

Although the so-called “labs-on-a-chip” or micro total analysis systems (micro TAS) fields hold high promise for applications in many fields, conventional fabrication processes based on the semiconductor industry such as photolithography have limitations in terms of productivity. Silicone elastomers are widely used for micromodeling and offer biocompatibility and chemical stability, but they are generally thermosetting and undergo unacceptable levels of shape deformation during curing. In this study, a photocurable silicone elastomer that has recently become commercially available was examined, and its basic optical, mechanical, and other related characteristics, along with its shape transfer capabilities, particularly its nanostructure replication characteristics, were measured in comparison with those of a representative existing thermosetting silicone elastomer. As a result, the photo-cured elastomer was shown to be superior to existing heat-cured silicone elastomers, having mechanical strength approximately three times greater, and was shown to have the same optical transmittance, extending from the near-IR to the near-UV regions. In addition, it was shown that the elastomer is sensitive to light in a wide range of wavelengths, from 254 to 600 nm, with no large difference in its curing characteristics, indicating that curing can be performed under a variety of common forms of illumination. Most importantly, the photocured elastomer provided extremely high replication accuracy due to its thermal shrinkage of less than 0.02%, compared to 2.91% in the heat-cured elastomer.

Theoretical and Experimental Study of Metallic Dot Agglomeration Induced by Thermal Dewetting

The authors previously developed a new fabrication method for a metal nanodot array, by combination of nanogroove grid patterning and thermal dewetting of metal deposited on a substrate. However, a comprehensive understanding of the thermal dewetting mechanism is necessary to improve the quality and control the variation of the metallic nanodot array. In this study, thermal dewetting-induced nanodot agglomeration mechanism is studied from a theoretical point of view. An analytical model is proposed, based on the total free energy of a dot and substrate system. The theoretical minimum and natural dot sizes show the same trend with an increase of contact angle. The theoretical model is validated by the experimental results.

Tool wear of a single-crystal diamond tool in nano-groove machining of a quartz glass plate

Tool wear characteristics of a diamond tool in ductile mode machining are presented in this paper. Nano-groove machining of a quartz glass plate was conducted to examine the tool wear rate of a single-crystal diamond tool. Effects of lubrication on the tool wear rate were also evaluated. A numerical simulation technique was developed to evaluate the tool temperature and normal stress acting on the wear surface. From the simulation results it was found that the tool temperature does not increase during the machining experiment. It is also demonstrated that tool wear is attributed to the abrasive wear mechanism, but the effect of the adhesion wear mechanism is minor in nano-groove machining. It is found that the tool wear rate is reduced by using water or kerosene as a lubricant.

Fabrication of Metallic Nanodot Arrays

Metal nanodot arrays exhibit unique optical characteristics, and they are expected to find widespread applications in biosensors and various optical devices. In this section, simple and efficient manufacturing processes are introduced for metal nanodot arrays. These processes are based on the combination of thin metal film coatings deposited on substrates and thermal dewetting. The first process discussed herein is a conventional thermal dewetting method. With this method, it is shown that the average dot diameter can be controlled based on the chosen M. Yoshino (*) Department of Mechanical Engineering, Tokyo Institute of Technology, Tokyo, Japan e-mail: myoshino@mes.titech.ac.jp M. Terano Department of Mechanical Systems Engineering, Okayama University of Science, Okayama, Japan e-mail: m_terano@mech.ous.ac.jp # Springer Nature Singapore Pte Ltd. 2018 J. Yan (ed.), Micro and Nano Fabrication Technology, Micro/Nano Technologies, https://doi.org/10.1007/978-981-10-6588-0_23-2 1 process conditions. The second process is based on the use of grid patterning on coated metal films. This process can allow fabrication of nanodot arrays with uniform dot diameters and achieve highly ordered alignment of dots. The third process generates a metal nanodot array based on a self-organization manner on a nanogrid-patterned substrate. It constitutes a high-productivity process based on the transfer of the metal nanodot array to an adhesive film. The basic mechanisms underlying these processes are discussed herein.