Yasunori Saotome

Microforming of Mems Parts with Amorphous Alloys

Microformability of new amorphous alloys in the supercooled liquid state and microforming techniques for the materials are shown. In the supercooled liquid state, the materials reveal perfect Newtonian viscous flow characteristics and furthermore exhibit an excellent property of microformability on a submicron scale. As for microforming techniques, microforging and micro extrusion of amorphous alloys are introduced in addition to the fabrication method of micro dies of photochemically machinable glass. As a result, amorphous alloys are expected as one of the most useful materials to fabricate micromachines.

Fabrication of nanodot array mold with 2 Tdot/in.2 for nanoimprint using metallic glass

Here, the authors fabricated a mold consisting of nanodot arrays with an 18-nm pitch and performed nanoimprinting of metallic glass for developing bitpatterned media (BPM) with an areal recording density of 2 Tbit/in.2. Specifically, they investigated the feasibility of SiO2/Si mold fabrication by metal mask patterning with focused ion beam assisted chemical vapor deposition (FIB-CVD) and reactive ion etching (RIE). SiO2 was etched with a mixed gas of CHF3 and O2, resulting in successful fabrication of convex nanodot arrays with an 18-nm pitch. The authors attempted nanoimprinting of Pd-based metallic glass with the fabricated SiO2 mold and clearly confirmed the replication of the fine nanohole pattern. These results suggest that the proposed FIB-CVD and RIE process is a promising method for fabricating ultrafine nanodot arrays and that metallic glasses are excellent nanoimprintable materials for mass-produced nanodevices such as BPM with ultrahigh recording density.

Compacting of various metal, alloy and ceramic powder using 20 kHz ultrasonic vibration compacting equipments with upper and lower vibration punches

−20 kHz ultrasonic vibration compacting system with 15-mm-diameter upper and lower vibration punches and a radial vibration die, and 20 kHz vibration compacting system using 5-mm-diameter upper and lower vibration punches are studied. Compacting of metal, alloy and ceramics powder is important process for powder metallurgy which is used for producing small and precise mechanical parts and required for various industry fields including electronics. Some complex metal alloy, amorphous alloy and fine ceramic powder such as zirconium are impossible to compact using only static pressure. Various powder are compacted with larger density and more uniform distribution compared that without vibration.

Fabrication of Molds with 25-nm Dot-Pitch Pattern by Focused Ion Beam and Reactive Ion Etching for Nanoimprint Using Metallic Glass

Here we attempted to fabricate molds (dies) of nanodot arrays with a 25-nm pitch and to nanoimprint metallic glass for developing bit-patterned media with an ultrahigh recording density of 1 Tbit/in.2. The mold-fabricating process consisted of mask patterning by focused ion beam assisted chemical vapor deposition (FIB-CVD) and reactive ion etching (RIE). We investigated the feasibility of a Pt-deposited metal etching mask on SiO2 on Si and diamond like carbon (DLC) on Al2O3 substrates, and achieved isolated convex nanodot arrays with a 25-nm pitch and an aspect ratio of 1.8 by RIE with O2 plasma on a DLC/Al2O3 substrate. Subsequently, we nanoimprinted Pt-based metallic glass by using the fabricated molds and successfully replicated fine concave nanohole arrays. The results suggest that the FIB-CVD/RIE process is a promising technique for fabricating ultrafine nanopatterned molds, and metallic glasses are ideal nanoimprintable materials for mass producing nanodevices such as bit-patterned media.