森田 昇

We developed novel cutting tools that had either microscale or nanoscale textures on their surfaces. Texturing microscale or nanoscale features on a solid surface allowed us to control the tribological characteristics of the tool. The effect of the texture shape on the machinability of an aluminum alloy was investigated with a turning experiment. The texture decreased the cutting force due to the corresponding reduction in the friction on the rake face. This effect strongly depended on the direction of the texture. These results indicate that the developed tools effectively improved the machinability of the alloy.

? 2008 by World Scientific Publishing Co. Pte. Ltd. All rights reserved. Atomic force microscopy (AFM) was originally developed for atomic resolution surface topography observations. Nowadays, it is also widely used for nanolithography. AFM-based lithography is an effective method compared to conventional photolithographic processes due to its simplicity, high resolution, and low cost. It can provide nanoscale stage control and the probing tip can be used as a lithographic tool. Therefore, various AFM-based nanoscale fabrication methods have been proposed using electrochemical oxidation, material transfer, mechanical lithography, and thermally induced modifications. This chapter will introduce the detailed processes and applications of AFM-based lithographic techniques.

Nanoscale fabrication of silicon substrate based on the use of atomic force microscopy (AFM) followed by chemical etching was demonstrated. A specially designed cantilever with a diamond tip, allowing the formation of damaged layer on silicon substrate by a simple scratching process, has been applied instead of conventional silicon cantilever for scanning. A thin damaged layer forms in the substrate at the diamond tip-sample junction along scanning path of the tip, which was found to be a low crystallized amorphous silicon layer. Hence, these sequential processes, called tribo-nanolithography, TNL, can fabricate 2D or 3D microstructures in nanometer range. Diamond tip fabrication processes for TNL follow the micro-patterning, wet chemical etching and CVD based on MEMS processes. The developed TNL tools show outstanding machinability against single crystal silicon wafer. Hence, they are expected to have a possibility for industrial applications as a micro-to-nano-machining tool. In our previous work, is has been clearly known that the damaged layer withstands against aqueous potassium hydroxide solution, while it dissolves in diluted hydro fluoric solution. This study demonstrates the effect of various machining parameters on mask layer, followed by wet chemical etching in potassium hydroxide and hydro fluoric solution. ? 2006 Elsevier B.V. All rights reserved.

This study investigated the nanomachining of metallic glass surfaces using an Atomic Force Microscope (AFM). To reveal the nanomachining characteristics of metallic glass, machining experiments were conducted under various machining parameters. The metallic glass was machined to fabricate an 8-nm-deep by 120-nm-wide groove pattern. It was found that metallic glass is a more challenging material to machine than single-crystal silicon. The tool life is significantly shorter, although it can be improved somewhat by machining in water. Observation of the machining residue revealed that continuous and shear cutting chips were generated that differed from those generated by machining amorphous silicon. ? 2007 Inderscience Enterprises Ltd.

Nano-scale fabrication of silicon substrate based on the use of atomic force microscopy (AFM) was demonstrated. A specially designed cantilever with diamond tip allows the formation of damaged layer on silicon substrate by a simple scratching process. A thin damaged layer forms in the substrate along scanning path of the tip. The damaged layer withstands against wet chemical etching in aqueous KOH solution. Diamond tip acts as a patterning tool like mask film for lithography process. Hence these sequential processes, called tribo-nanolithography, TNL, can fabricate 2D or 3D micro structures in nanometer range. This study demonstrates the fabrication processes of the micro cantilever and diamond tip as a tool for TNL. The developed TNL tools show outstanding machinability against single crystal silicon wafer. Hence, they are expected to have a possibility for industrial applications as a micro-to-nano machining tool.

The etching resistance characteristics of a Focused Ion Beam (FIB) irradiated silicon surface against KOH are investigated in this study. An FIB irradiated silicon surface can withstand etching in KOH solution, whereas the non-irradiated area is etched and consequently, a protruding nanostructure can be fabricated on the irradiated area. Height dependence of the nanostructure on the FIB irradiating conditions is investigated in order to control the shape of the nanostructure for application to three-dimensional nanofabrication. As a consequence, it was found that the height of the nanostructure can be controlled by FIB irradiating conditions such as dose and acceleration voltage. The mechanism is investigated by a selective etching method using HF solution. The results of a simulation indicate that the amorphous layer induced by ion irradiation is strongly related to this phenomenon. In addition, surface roughness and line width dependence was investigated, and these results indicate the potential use of this method as a novel three-dimensional nanofabrication process. Copyright ? 2006 Inderscience Enterprises Ltd.