Yutaka Mihara

Atomic Force Microscope Cantilever Array for Parallel Lithography of Quantum Devices

Arrayed atomic force microscope (AFM) cantilevers for parallel scanning probe lithography (SPL) have been fabricated by silicon micromachining. Fabrication is based on three KOH etching steps and local oxidation processes. The curvature radius of the tips is as sharp as 20 nm. A laser beam focused onto the middle probe enables us to observe the wafer for alignment and confirm the patterns after the SPL operation. Parallel SPL on N-octadecyltrimethoxysilane (ODS) self-assembled monolayer (SAM) films is susessfully demonstrated with five probes. Good alignment and homogeneity are obtained with simple operation. Parallel SPL for parallel quantum device fabrications is also reported.

Self-hold and precisely controllable optical cross-connect switches using ultrasonic micro motors

In this paper, we propose new optical cross-connect switches using ultrasonic micro motors, whose features are self-hold, precise control, and low electric power consumption. Two methods are examined for optical beam deflection. One method is moving the lens and the other is rotating the mirror by using ultrasonic micro motors. The light from the optical fiber is collimated using a self-focusing (SELFOC) lens and is deflected by moving the lens, with an ultrasonic linear motor, perpendicularly to the fiber axis. The light is then coupled to another fiber. Another proposed method is to use reflection mirrors. This structure is composed of a magnetized material attached to a micro mirror and a permanent magnet mounted on a shaft of an ultrasonic rotation motor. The reflected beam is deflected by rotating the mirror. In both methods, precise beam deflection is demonstrated, and optical switching characteristics are confirmed.

Fabrication of a micro elliptical collimator lens for a beam shape form of a Laser Diode

LD (Laser Diode) has different divergent angles in horizontal direction and direction, for example the divergent light angle is from 10[deg] to 35[deg] in horizontal direction and from 30[deg] to 40[deg] in vertical direction. To form the beam shape, an aspheric lens or an anamorphic lens has been used. But there are some problems in position alignment of lens or production cost. In this research, we designed and fabricated a lens which forms beam shape by using only one lens that has a different curvature radius in horizontal and vertical directions, in input surface and output surface. As a fabrication method at low cost and high accuracy, we formed UV cure material which is dropped on the substrate to the lens shape mother die by changing the area of the hydrophobic property. And we casted the lens by using the metal mold which is formed by electro plating to the mother die. We evaluated the optical characteristics of the focused LD beam using the fabricated lens. As the result, we confirmed the improvement of the beam shape of the LD by using the fabricated collimator lens.

Fabrication and evaluation results of a micro elliptical collimator lens for a beam shape form of laser diode

This paper describes a new fabrication process of a micro elliptical collimator lens to form a beam shape for LD(Laser Diode), and the evaluation results of the optical characteristic for this lens. Beam shape of LD is an ellipse because divergent light angle is different between horizontal and vertical direction, which increases a coupling loss with an optical fiber. In this presentation, we propose the lens to form the divergent light of an elliptical beam shape to the collimated light of a circular beam shape. This lens makes it possible to reduce the coupling loss with the optical fiber. For this purpose, we designed one lens, which has different curvature radiuses between incident and output surfaces. In the incident surface, the divergent light is formed to the convergent light, and in the output surface, the convergent light is formed to the collimated light. We simulated the optical characteristic of this lens, and designed for various parameters. In order to fabricate this lens, we propose a new process using a chemically absorbed monomolecular layer, which has an excellent hydrophobic property. This layer is patterned and deposited by a photolithographic technique. Next, we drop a UV(Ultra Violet) cure material on the hydrophilic area, as the result, we can fabricate a micro elliptical lens shape. The curvature radius of this lens can be controlled by the amount of a dropped UV cure material and an elliptical pattern size in horizontal and vertical direction. The formed lens shapes are transferred by the electro-plating and then the micro dies are fabricated. And they are used for molding the plastic lens.

Fabrication of Arrayed Waveguide Grating by the casting method using a micro-die

We proposed a fabrication process of an Arrayed Waveguide Grating (AWG) for a Wavelength Division Multiplexing (WDM) system by a casting method using a micro-die. First, we proposed a fabrication process of a micro-die by an electro-plating after fabricating the mother shape with a thick photo resist SU-8. Then, we aim to fabricate the AWG for the WDM system using the fabricated micro-die with an UV cure material. By using SU-8 resist, the fabrication process using dry etching equipments cold be deleted. As the result, it is possible to decrease fabrication time and cost, and finally we could fabricate an AWG by the casting method.

Evaluation of Scale Dependent of Fast Fracture Strength of Micro Component

In order to design the MEMS having good reliability, it is necessary to know the mechanical properties such as strength, fracture toughness and fatigue strength of micro components. In this paper, the fatigue testing machine was made. The examination of the fast fracture strength against the several kinds of specimens which dimensions were different each other was carried out. And volume dependency of the strength was discussed.

Measurement Technology for Relative Position and Attitude of Micro-manipulator

近年, MEMS技術は様々な高機能微小構造体を提供することが可能となっており, これらの高機能微小構造物をウェハから取り出して機能部品として活用することができれば, さらに応用範囲を拡張することが期待できる. そこで, MEMSを機能部品として扱うためのMEMSの位置姿勢同時計測技術の確立が重要であると考えている. そこで, 我々はMEMSの相対位置姿勢計測技術として近接共焦点位置姿勢同時計測手法を提案した. 本報では, 提案手法の原理確認及び精度検証を行い, その実用性について検証を行った.

Self-hold, precisely controllable and low power consumption optical cross-connect switch using ultrasonic micro motors

Novel optical cross-connect switches using ultrasonic micro motors are proposed, which have self-hold, precise controllability, and low power consumption. In the system, the precise beam deflection is demonstrated and the optical switching characteristics are confirmed.

Development of Nano Probes for Electrical Measurement of Biomolecules

We have developed new micromachined opposing nano probes for electrical measurement of biomolecules. Since comb-drive micro actuators were integrated and connected to the nano probes electrically isolated from silicon piece, it will enables us to measure electro-mechanical characteristics of a biomolecule such as piezoelectricity. The probe structure was defined by etching of a 25[μm]-thick silicon-on-insulator wafer (SOI) using an inductively coupled plasma reactive ion etching apparatus (ICP-RIE). To obtain the tip radius of less than 10[nm] and to align two probe tips, new process sequence was designed by combining wet anisotropical etching of silicon with the ICP-RTE. Another type with probes directing outward was also developed.