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

• 한국정밀공학회지
• /
• 제22권11호
• /
• pp.173-181
• /
• 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 $25\%$.

• 한국정밀공학회지
• /
• 제23권9호
• /
• pp.179-189
• /
• 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
• /
• 정보저장시스템학회 2005년도 추계학술대회 논문집
• /
• pp.195-196
• /
• 2005

We report the new design of a miniature electromagnetic actuator for probe-based data storage with anti-vibration mechanism. The actuator consists of a media substrate, silicon frame, 2 pairs of magnets, a spacer, and a printed circuit board (PCB). The total area of the device is $11.2{\times}11.2 mm^2$ while the data recording area is $7.4{\times}7.4 mm^2$. A net momentum fee structure was included for high vibration resistance. The simulation shows that the lateral vibration can be reduced to below 100 nm for 1 G acceleration if the counter mass is adjusted with $1\%$ difference. The peak power for ${\pm}50 {\mu}m$ displacement is below 50 mW for a actuator with a resonance at 200 Hz.

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

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2004년도 추계학술대회 논문집
• /
• pp.373-378
• /
• 2004

Recently the electrostatic 2-axis MEMS stages have been fabricated for the purpose of an application to PSD (Probebased Storage Device). However, most of them have low area efficiency, which is undesirable as data storage devices, since all of the components (springs, comb electrodes, anchors, platform, etc.) are placed in-plane. In this paper, we present a novel structure of electrostatic 2-axis MEMS stage that is characterized by having large area platform. For large area efficiency, the actuator part consisting of mainly comb electrodes and springs is placed right below the platform. In this article, the structures and operational principle of the MEMS stages are described, followed by design procedure, structural and modal analysis using FEM(Finite Element Method). The area efficiency of the MEMS stage was designed to be about 55％, that is very large compared with conventional ones having a few percentage.

• 정보저장시스템학회논문집
• /
• 제2권4호
• /
• pp.224-229
• /
• 2006

There has been studied flow to minimize the spot size to increase data capacity. Optical data storage devices are being developed near practical limits with wavelength and NA of 405nm and 0.85. There has been studied many types of next generation storage devices such as blu-ray multilayer system, probe based data storage and holographic data storage. Among these data storage devices, solid immersion lens(SIL) based near field recording (NFR) has been widely studied. In this system, SIL is the key component that focuses the laser beam with a very small size which enables ultra high data capacity. Therefore, optical performance evaluation system is required for SIL assembly. In this dissertation, a simple and accurate SIL assembly measurement method is proposed with wedge plate lateral shearing interferometer(LSI). Wedge plate LSI is cheaper than commercialized interferometer, robust to the vibration and the moving distance for phase shifting is large that is order of micrometer. We designed the thickness, wedge angle, material, surface quality and wavelength of wedge plate as 1mm, 0.02degree, fused silica, lamda/10(10-5) and 405nm, respectively. Also, we confirmed simulation and experimental results with quantitative analysis. This simple wedge plate LSI can be applied to different types of SIL such as solid immersion mirror(SIM), hemispherical, super-hemispherical and elliptical SIL.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2002년도 추계학술대회논문집
• /
• pp.582-587
• /
• 2002

Current information storage devices, such as HDD, CD/DVD-ROM/RW, probe-based memory and hologram memory, are compared with biological information storage mechanisms in DNA and brain memory. Newly developed approaches to overcome the limit of storage capacity are introduced in both magnetic and optical recording devices. Linear and areal density of information stored in the biological and mechanical storages are compared for the applications and developments of new storage devices.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제1권1호
• /
• pp.84-93
• /
• 2001

An electromagnetic micro x-y stage for probe-based data storage (PDS) has been fabricated. The x-y stage consists of a silicon body inside which planar copper coils are embedded, a glass substrate bonded to the silicon body, and eight permanent magnets. The dimensions of flexures and copper coils were determined to yield $100{\;}\mu\textrm{m}$ in x and y directions under 50 mA of supplied current and to have 440 Hz of natural frequency. For the application to PDS devices, electromagnetic stage should have flat top surface for the prevention of its interference with multi-probe array, and have coils with low resistance for low power consumption. In order to satisfy these design criteria, conducting planar copper coils have been electroplated within silicon trenches which have high aspect ratio ($5{\;}\mu\textrm{m}$in width and $30{\;}\mu\textrm{m}$in depth). Silicon flexures with a height of $250{\;}\mu\textrm{m}$ were fabricated by using inductively coupled plasma reactive ion etching (ICP-RIE). The characteristics of a fabricated electromagnetic stage were measured by using laser doppler vibrometer (LDV) and dynamic signal analyzer (DSA). The DC gain was $0.16{\;}\mu\textrm{m}/mA$ and the maximum displacement was $42{\;}\mu\textrm{m}$ at a current of 180 mA. The measured natural frequency of the lowest mode was 325 Hz. Compared with the designed values, the lower natural frequency and DC gain of the fabricated device are due to the reverse-tapered ICP-RIE process and the incomplete assembly of the upper-sided permanent magnets for LDV measurements.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2002년도 추계학술대회논문초록집
• /
• pp.360.1-360
• /
• 2002

Current information storage devices, such as HDD, CD/DVD-ROM/RW, probe-based memory and cabon nano tubes, are compared with biological information storage mechanisms in DNA and brain memory. Various biological components in living cells are analyzed based on "irreducible complexity" of intelligent design concept. Linear and arel density of information stored in the biological and mechanical storages are compared for the applications and developments of new storage devices.