• 정보저장시스템학회논문집
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• 제2권1호
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• pp.65-70
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• 2006

In the information storage development, the trend of the storage device is to increase the recording density. Among such an effort, near-field probe recording is spotlighted as a method of high increasing recording density. For the successfully embodiment of storage device, the actuating mechanism of near-field probe is essentially designed. In this paper, we suggest the slider similar with conventional HDD and design the slider using near-field probe for the purpose of applying the slider in order to control gap between probe and media. The most important object of slider design is to guarantee the flying ability and stability. For achievement of these design objects, we perform two step of optimal design process. The media is supposed to model as random displacement, which is only considered roughness of disk surface. The design slider is analyzed with dynamic state in assumed media. At this process, the optimal model is confirmed to stable flying stability.

• 정보저장시스템학회:학술대회논문집
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• 정보저장시스템학회 2005년도 추계학술대회 논문집
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• pp.171-176
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• 2005

In the information storage development, the trend of the storage device is to increase the recording density. Among such an effort, near-field probe recording is spotlighted as a method of high increasing recording density. For the successfully embodiment of storage device, the actuating mechanism of near-field probe is essentially designed. In this paper, we suggest the slider similar with conventional HDDs and design the slider using near- field probe for the purpose of applying the slider in order to control gap between probe and media. The most important object of slider design is to guarantee the flying ability and stability. For achievement of these design objects, we perform two step of optimal design process. The media is mod! eled as random displacement, which is only considered roughness of disk surface. The design slider is analyzed with dynamic state in assumed media. At this process, the optimal model is confirmed to stable flying stability.

• 정보저장시스템학회논문집
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• 제3권2호
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• pp.73-80
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• 2007

Atomic Force Microscopy (AFM)방식을 이용한 Scanning probe Data Storage (SDS) 시스템은 array cantilever 를 이용하여 나노 단위로 데이터 읽기, 쓰기를 하는 시스템이다. 따라서 미디어가 있는 stage 의 x 축과 y 축 및 두 축간 coupling 을 고려한 제어기 설계가 요구된다. 본 논문은 SDS 시스템의 축간 coupling 을 고려하지 않은 기존의 제안된 LQG 에 PI 를 추가한 제어기 구조를 사용한다. 두 축간 coupling 공진의 영향을 최소화 하기 위해 convex optimization 으로 설계된 최적의 position profile를 기준 입력신호로 사용한다. 제안된 제어기를 SDS 시스템에 적용하여 모의실험을 하고 그 결과 position profile 로 인해 각 축간 coupling 공진 영향이 감소하여 tracking performance 가 기존의 LQG 제어기 보다 향상된 것을 확인한다.

• 한국정밀공학회지
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• 제22권11호
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• pp.173-181
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• 2005

We report on the design and fabrication of an electrostatic 2-axis MEMS stage possessing a platform with a size of $5{times}5mm^2$. The stage, as a key component, would be used in developing probe-based storage devices in the future. It was fabricated by forming numerous $5{\times}5{\mu}m^2$ etching holes in the central platform, as a result, reducing the total number of masks to 1, thereby simplifying the whole fabrication process. Experimental results show that the driving range of the stage was $32{\mu}m$ at the supplied voltage of 20V and the natural frequency was approximately 300Hz. The mechanical coupling between x- and y-motion was also measured and verified to be $25\%$.

• 한국공작기계학회논문집
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• 제15권3호
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• pp.82-90
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• 2006

Recently the electrostatic 2-axis MEMS stages have been fabricated for the purpose of an application to PSD (Probe-based Storage Device). However, all of the components(platform, comb electrodes, springs, anchors, etc.) in those stages are placed in-plane so that they have low areal efficienceis, which is undesirable as data storage devices. In this paper, we present a novel structure of an electrostatic 2-axis MEMS stage that is characterized by having large area platform. for obtaining large area efficiency, the actuator part consisting of mainly comb electrodes and springs is placed right below the platform. The structure and operational principle of the MEMS stage are described, followed by a design procedure, structural and modal analyses using FEM(Finite Element Method). The areal efficiency of the MEMS stage was designed to be about 25%, which is very large compared with the conventional ones having a few percentage.

• 정보저장시스템학회논문집
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• 제3권2호
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• pp.86-93
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• 2007

In this paper we explain why future probe storage systems will use patterned media. As a model system, magnetic patterned media will be discussed, even though their data density is limited to about $7Tbit/in^2$. The first results on magnetic probe storage on patterned media are presented, and the problem of switching field distribution is discussed in detail. Finally we will present the first steps into two-dimensional coding for patterned media.

• 정보저장시스템학회논문집
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• 제1권1호
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• pp.73-77
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• 2005

In this paper, a new silicon nitride cantilever integrated with silicon heater and piezoelectric sensor has been firstly developed to improve the uniformity of the initial bending and the mechanical stability of the cantilever array for thermo-piezoelectric SPM(scanning probe microscopy) -based data storages. This nitride cantilever shows thickness uniformity less than $2\%$. Data bits of 40 nm in diameter were recorded on PMMA film. The sensitivity of the piezoelectric sensor was 0.615 fC/nm after poling the PZT layer. For high speed operation, 128${\times}$128 probe array was developed.

• 한국정밀공학회지
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• 제23권6호
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• pp.166-173
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• 2006

In this study, a probe array has been developed for use in a data storage device that is based on scanning probe microscope (SPM) and MEMS technology. When recording data bits by poling the PZT thin layer and reading them by sensing its piezoresponse, commercial probes of which the tip heights are typically shorter than $3{\mu}m$ raise a problem due to the electrostatic forces occurring between the probe body and the bottom electrode of a medium. In order to reduce this undesirable effect, a poly-silicon probe with a high aspect-ratio tip was fabricated using a molding technique. Poly-silicon probes fabricated by the molding technique have several features. The tip can be protected during the subsequent fabrication processes and have a high aspect ratio. The tip radius can be as small as 15 nm because sharpening oxidation process is allowed. To drive the probe, electrostatic actuation mechanism was employed since the fabrication process and driving/sensing circuit is very simple. The natural frequency and DC sensitivity of a fabricated probe were measured to be 18.75 kHz and 16.7 nm/V, respectively. The step response characteristic was investigated as well. Overshoot behavior in the probe movement was hardly observed because of large squeeze film air damping forces. Therefore, the probe fabricated in this study is considered to be very useful in probe-based data storages since it can stably approach toward the medium and be more robust against external shock.

• 한국정밀공학회지
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• 제23권9호
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• pp.179-189
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• 2006

Recently the electrostatic 2-axis MEMS stages have been fabricated f3r the purpose of an application to PSD (Probe-based Storage Device). However, all of the components (platform, comb electrodes, springs, anchors, etc.) in those stages are placed in-plane so that they have low areal efficiencies such as a few percentage, which is undesirable as data storage devices. In this paper, we present a novel structure of an electrostatic 2-axis MEMS stage that is characterized by having a large areal efficiency of about 25%. For obtaining large area efficiency, the actuator part consisting of mainly comb electrodes and springs is placed right below the platform. The structure and operational principle of the MEMS stage are described, followed by a design and analysis, the fabrication and measurement results. Experimental results show that the driving ranges of the fabricated stage along the x and y axis were 27$\mu$m, 38$\mu$m at the supplied voltages of 65V, 70V, respectively and the natural frequencies along x and y axis were 180Hz, 310Hz, respectively. The total size of the stage is about 5.9$\times$6.8mm$^2$ and the platform size is about 2.7$\times$3.6mm$^2$.

• 정보저장시스템학회:학술대회논문집
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• 정보저장시스템학회 2005년도 추계학술대회 논문집
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• pp.47-52
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• 2005

A lot of information storage devices have been introduced and developed for recently years. The trends of those devices are high capacity, compact size, low power consumption, reliability, and removability for data interchange with other device. As a satisfaction of these trends, near-field technique is in the spotlight as the next generation device. In order for a near-field recording to be successfully implemented in the storage device, a slider and suspension is introduced as actuating mechanism. The optical slider is designed considering near-filed optics. Suspension is not only supports slider performance, and tracking servo capacity but also meets the optical characteristics such as tilt aberration, and guarantee to satisfy shock performances for the mobility fir the actuator. In this study, the optical slider and the suspension for near-field probe array are designed and analyzed considering dynamic performance of head-gimbal assembly and shock simulation..