A5089031285- Adhesion, Friction, and Surface Interactions
- Iterative Learning Control Systems
- Advanced MEMS and NEMS Technologies
- Tribology and Lubrication Engineering
- Advanced Measurement and Metrology Techniques
- Force Microscopy Techniques and Applications
- Advanced Sensor and Energy Harvesting Materials
- Mechanical and Optical Resonators
- Semiconductor Lasers and Optical Devices
- Advanced Surface Polishing Techniques
- Metal and Thin Film Mechanics
- Piezoelectric Actuators and Control
- Magnetic properties of thin films
- Additive Manufacturing and 3D Printing Technologies
- Near-Field Optical Microscopy
- Parallel Computing and Optimization Techniques
- Video Surveillance and Tracking Methods
- Nanofabrication and Lithography Techniques
- Autonomous Vehicle Technology and Safety
- Block Copolymer Self-Assembly
- Fluid Dynamics and Thin Films
- Surface Roughness and Optical Measurements
- Ferroelectric and Negative Capacitance Devices
- Advanced Data Storage Technologies
- Copper Interconnects and Reliability
The University of Tokyo
2019-2023
Western Digital (United States)
2013-2021
Western Digital (Japan)
2013-2015
Hitachi Global Storage Technologies (United States)
2003-2009
Hitachi (Japan)
2004-2007
IBM Research - Almaden
1998-2003
IBM Research - Tokyo
1992-2002
IBM (United States)
1996-1999
Bit Patterned Media (BPM) for magnetic recording provide a route to densities $>1 Tb/in^2$ and circumvents many of the challenges associated with conventional granular media technology. Instead bit on an ensemble random grains, BPM uses array lithographically defined isolated islands, each which stores one bit. Fabrication is viewed as greatest challenge its commercialization. In this article we describe fabrication method combines e-beam lithography, directed self-assembly block copolymers,...
Making submicron interelectrode gaps is the key to reducing driving voltage of a micro comb-drive electrostatic actuator. Two new fabrication technologies, oxidation machining and post-release positioning method, are proposed realize gaps. types actuator (a resonant type nonresonant type) with were successfully fabricated their operational characteristics tested experimentally. The drive was found be lower than that existing actuators. stability actuators discussed.< <ETX...
A MEMS microactuator provides a low-cost and high-performance solution to realize high track densities of HDD, because the batch fabrication process its clean mechanical characteristics. However, servo system control such dual-stage tends be more complicated than conventional HDD system. In this paper, simple efficient design method controller for applications is described. The experimental results following with actuator using VCM showed that fourth-order can achieve bandwidth 2 kHz.
Reports on the design, fabrication, and testing of an electrostatic microactuator for a magnetic hard disk drive (HDD) tracking servo. The design requirements are investigated. These include high Z-directional stiffness, low in-plane structural aspect ratio, large output force, area efficiency, cost, mass batch production. An area-efficient rotary was devised, microactuators were successfully fabricated using innovative processing technologies. has thickness 40 /spl mu/m with minimum...
In this paper, a batch microfabrication process is presented for creating high aspect ratio, micron-sized helical and toroidal inductors with Q greater than or equal to 50 at multi-GHz frequencies. With maximum processing temperature of only 220/spl deg/C, the can be fabricated on top standard CMOS wafers. This also used create "inductor chiplets", which are polymer-encapsulated same form factor as an EIA (Electronics Industries Association) 0201 surface mount device. The chiplets assembled...
A flexure-based rotary electrostatic microactuator is described. This for application in a high track-density hard disk drive (HDD). It fabricated using aspect-ratio stencil electroplating process. paper emphasizes the practical system-level issues that affect device design. The micro-actuator demonstrated 3.5" form-factor HDD. With servo bandwidth of 5 kHz, one-track seek can be completed under 0.2 ms. batch-fabricated electro-static provides low-cost, high-performance solution achieving...
All previous thermal modeling on heat exchange between hard disk drive (HDD) head and media treated as a sink with uniform ambient temperature. However in heat-assisted magnetic recording (HAMR) system, the temperature is no longer at hot spot center can reach high 800 to 1000 K depending layer's Curie In this paper, both air bearing flow are included formulating transfer across head-media interface. Numerical results for waveguide only slider metallic near-field transducer (NFT) presented...
A micromachined device developed to perform displacement-controlled tunneling is described. Its performance was experimentally confirmed. The lateral unit (LTU), composed of a comb-drive actuator, tip, and an opposing wall integrated on the same wafer fabricated using surface micromachining with only one photomask. Integration tip its eliminated coarse positioning specimen, realized fully unit. configuration easy fabricate suitable for integrating other structures such as atomic force...
This paper describes the design, fabrication, and operational characteristics of a MEMS milliactuator designed for servo tracking in hard-disk drive (HDD). The actuator is to increase bandwidth an HDD pack more recording tracks on disk. An Invar (low thermal expansion metal) electrode position process was developed meet stability requirement. electroplated Invar's coefficient as low 6.3/spl times/10/sup -6//K, which almost half that pure nickel. For plating mold pattern definition,...
The authors present the design of an array-driven ultrasonic microactuator. Unlike a conventional motor, microactuator consists many distributed modules, using concept similar to that array. With it is difficult control object locally and obtain sufficient resolution rotor position orientation without closed-loop control, since motion produced by traveling waves on whole diaphragm. However, can with high accuracy even in open-loop because each module. It uses perpendicular motion, which...
A moving-slider microactuator for high track pitch HDDs was investigated. new design called a bipolar that enables both stroke and good linearity proposed. For easier assembly, fabrication technique developed the bonding pads on sidewall of chip. The assembled into server-class HDD, servo bandwidth 8 kHz demonstrated with an 80-kHz sampling rate.
We report on the fabrication of 1 Tdot/in2 bit patterned media with high coercivity (HC) and narrow intrinsic switching field distribution (iSFD) based nanoimprint from a master pattern formed by e-beam guided block copolymer assembly onto carbon hard mask subsequent transfer via etching into thin CoCrPt perpendicular anisotropy recording layer. demonstrate that an additional vacuum annealing step after layer Carbon removal not only yields recovery undesired damage island edges, but actually...
This paper describes a micro-actuator for high-bandwidth tracking servo, where is attached between slider and suspension, moves the relative to suspension. The frequency response measurement proved that this can be modeled as an ideal spring-mass-damper system up 80 kHz, so very high bandwidth servo easily designed. maximum of 6.4 kHz was achieved in drive level experiment, which highest ever demonstrated level. A rapid step time 0.2 mS 0.6 /spl mu/m also achieved. experimental not limited...
Resonant and nonresonant operation of submicron gap, electrostatic, comb-drive actuators is reported. Using a single-mask process 4- mu m-thick phosphorus-doped polysilicon layer as the structural material, resonant actuator nonresonant, linear were fabricated tested. displacement amplitude +or-5.2 m was observed in with 0.3- gaps when an AC drive voltage 11.5 V (peak) without bias applied. Maximum displacements 3.6 0.2- DC 11.1 A postrelease assembly technique used to position fix...
The design and fabrication of a surface micromachined electrostatic wobble micromotor are reported. rotor is located outside the stator, aims to generate torque on order 10/sup -4/-10/sup -5/ Nm. This has significant advantage driving passive structures which coupled directly, magnetically, or by lubricant. Since generated proportional cube radius dimensions motor must be millimeters in diameter 10 mu m thickness. Electroplated copper was used as structural material because its low residual...
A silicon microprobing array made by the micromachining technique is proposed for testing and burn-in at die level. The on a substrate to avoid misalignment caused mismatching of thermal expansion rates. be tested placed face down surface, compliance in direction perpendicular realized means membrane covering microcavity substrate. was successfully fabricated, basic contact experiment showed that it can establish good even high temperatures. resistivity 0.5 /spl Omega/ measured, carried out...
Low thermal expansion metal such as Invar is suitable for MEMS application, where the dimension stability requirement very high over a wide temperature range. electrodeposition process was developed method to fabricate structure. The effect of plating parameters were investigated develop optimized deposition process. film obtained in this research has coefficient low 6.3 PPM/K, which almost half that pure nickel. compatibility rest fabrication proved through prototyping microstructure.
A micro-actuator which can largely improve the capacity and performance of current hard-disk drives (HDDs) was investigated. This is located between a slider suspension, moves magnetic head (attached on edge slider) with very high speed accuracy. As result, extremely data-track density (thus, capacity) fast access time be achieved. First, requirements for this actuator were investigated, new design methods fabrication technologies developed, including area-efficient electrode design,...
The authors present a processing technique consisting of polysilicon etching, thermal oxidation polysilicon, and silicon dioxide wet-etching which results in the fabrication operational, submicron gaps between electrodes side-drive actuators, without need for etching capability. As one example an application machining, this was used to define operational electrostatic comb-drive actuator type linear, actuator. Experimental have verified fundamental principle indicate that it is possible...
A micromachined W-band iris filter was successfully demonstrated using micro hot embossing and selective electroplating technologies. The design follows the insertion loss method with a Chebyshev polynomial to synthesize desired spectral responses numerical simulations were performed finite-element tool, high frequency structure simulator (HFSS), study effects of thickness on bandwidth center frequency. measured prototype performance has transmission -3.49 dB return -18 at resonant 95 GHz....
Fabrication by the dry release of electroplated metallic structures is reported. This method results in thick structural height and high yield. It allows micromechanism to be integrated with electrical circuits, needle-shaped residual sacrificial layer can used as bearing micromotor. As examples this method, micromotors overhanging are demonstrated. A new micromotor design proposed. Its fabrication successful testing described. Overhanging such an LTU (lateral tunneling unit) AFM (atomic...
A microactuator that moves the slider of a hard disk drive (HDD) was fabricated using MEMS techniques. suspension-mounted PZT milliactuator also manufactured. Both actuators were assembled and tested in 10,000 RPM server-class HDDs. The has resonance at 2.2 kHz can be controlled by feedback, virtually no other modes up to 100 kHz. first mode is much higher 8 kHz, but there are many more below secondary enable high tracking servo bandwidth, which necessary achieve ultra-high track densities....
Abstract Integration issues of a micro-actuator for HDD tracking servo were investigated, and many innovative technologies developed. In order to electrically connect magnetic head the external electronics, we devised “integrated flexible wire” structure, which is micro-fabricated electrical wire. Connection between micro-actuator’s bonding pad suspension was realized by an “inter-connect module,” miniature printed circuit. components done “solder bumper” process, precise solder ball...
A moving-slider microactuator that enables both high stroke and good linearity for track pitch HDDs (hard disk drives) was investigated. new design called a "bipolar microactuator" proposed maintains proper slider grounding. fabrication technique developed allows the bonding pads to be manufactured on sidewall of chip easier assembly into an HDD. The used achieve open loop servo bandwidth 8 kHz at 80 sampling rate in server-class Higher bandwidths may achieved with higher rates. description...