• JSTS:Journal of Semiconductor Technology and Science
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• v.7 no.3
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• pp.133-139
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• 2007

Future MEMS systems will be composed of larger varieties of devices with very different functionality such as electronics, mechanics, optics and bio-chemistry. Integration technology of heterogeneous devices must be developed. This article first deals with the current development trend of new fabrication technologies; those include self-assembling of parts over a large area, wafer-scale encapsulation by wafer-bonding, nano imprinting, and roll-to-roll printing. In the latter half of the article, the concept towards the heterogeneous integration of devices and functionality into micro/nano systems is described. The key idea is to combine the conventional top-down technologies and the novel bottom-up technologies for building nano systems. A simple example is the carbon nano tube interconnection that is grown in the via-hole of a VLSI chip. In the laboratory level, the position-specific self-assembly of nano parts on a DNA template was demonstrated through hybridization of probe DNA segments attached to the parts. Also, bio molecular motors were incorporated in a micro fluidic system and utilized as a nano actuator for transporting objects in the channel.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.2236-2238
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• 2000

The paper represents the fabrication of an electrostatic micro actuator for optical devices. The micro actuator consists of a plate suspended four p+ silicon cantilevers and an electrode on a glass substrate. The cantilever curls down because of the residual stress gradient in p+ silicon. When input voltage is applied between the p+ cantilevers and the electrode. the cantilevers are pulled toward the electrode by the electrostatic force. The displacement of the plate is measured with a laser displacement meter for various input voltage and frequencies.

• Journal of Power Electronics
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• v.5 no.4
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• pp.247-256
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• 2005

In order to harvest power in an efficient manner from a micro piezoelectric (PZT) device for charging the battery of a remote system, a new AC/DC resonant pulse power converter is proposed. The proposed power converter has two stages in the power conversion process. The first stage includes N-type MOSFET full bridge rectifier. The second stage includes a boost converter having an N-type MOSFET and a P-type MOSFET. MOSFETs work in the $1^{st}$ or $3^{rd}$ quadrant region. A small inductor for the boost converter is assigned in order to make the size of the power converter as small as possible, which makes the on-interval of the MOSFET switch of the boost converter ultimately short. Due to this short on-interval, the parasitic junction capacitances of MOSFETs affect the performance of the power converter system. In this paper, the performance of the new converter is analytically and experimentally evaluated with consideration of the parasitic capacitance of switching devices.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.4
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• pp.658-665
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• 2012

Micro-EDM is widely used in metallic pattern, electronics, nuclear power and industry in the form of precision process. The improvement of Electro Discharge Machining has been on a steady progress since $19^{th}$ century. The technology has overcome the limits of the traditional precision process, enabling micro-EDM, micro electrolytic machining, micro drilling, micro punching and laser beam machining, which create versatile products with smaller sizes. What have been known about the major feature of Micro-EDM is high thermal energy so that their products are free from the hardness of their products as long as they are electrical conductor. However, each metal is suspected to have different features and natures even if they are created through the same procedure. In this thesis, the methodology of Micro-EDM and how to categorize them are explained. Also, the nature of the examined materials with surface shape and surface roughnes are analyzed. The results of the experiments are expected to understand surface roughness and workability of other materials for Micro-EDM.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.109.1-109
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• 2002

This paper presents a macro/micro flip chip mounting head system for precise force control. In the proposed macro/ micro system, the macro actuator is conventional do servomotor with a ball screw mechanism and the micro actuator is a voice coil motor(VCM) that consists of four NdFeB magnets and a winded moving coil. For force control, a sensitive strain-gauge force sensor is mounted in the micro actuator. Through harmonic motion between macro and micro actuator, we would like to get precise contact force control when small sized flip chip is mounted on flexible substrate in high speed. In order to show the effectiveness of the proposed macro/micro flip chip mounting head system, we com...

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.1
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• pp.35-41
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• 2009

This paper proposes a stand alone type single-phase fuel cells micro-source with a voltage sag compensator for compensating the ac output voltage variations (sag or swell) of micro-source. The proposed micro-source is consist of a PEM(polymer electrolyte membrane) fuel cells simulator, a full bridge de converter, a 60Hz PWM(pulse width modulation) VSI(voltage source inverter), and a voltage sag compensator. Voltage sag compensator is similar to the configuration of hybrid series active power filter, and it is directly connected to micro-source through the injection transformer. Compensation algorithm of a voltage sag compensator adopts a single phase p-q theory. Effectiveness of the proposed the system is verified by the PSIM(power electronics simulation tool) simulation in the steady state and transient state which the proposed system is able to simultaneously compensate the harmonic current and source voltage sag or swell.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1927-1931
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• 2003

Nanometer-sized structures are being applied to many fields including micro/nano electronics, optoelectronics, quantum computing, biosensors, etc. Micro contact printing is one of the most promising methods for manufacturing the nanometer-sized structures. The crucial element for the micro contact printing is the nano-resolution printing technique using polymeric stamps. In this study, a multi-scale analysis scheme for simulating the micro contact printing process is proposed and some useful analysis results are presented. Using the slip-link model [1], the dependency of viscoelasticity on molecular weight of polymer stamp is predicted. Deformation behaviors of polymeric stamps are analyzed using finite element method based upon the predicted viscoelastic properties.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.5
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• pp.58-64
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• 2008

A 6Gbps 1:2 demultiplexer(DEMUX) IC using $0.18{\mu}m$ CMOS was designed and fabricated. For high speed performance current mode logic(CML) flipflop was used and inductive peaking technology was used so as to obtain higher speed than conventional Current mode logic flipflop. On-chip spiral inductor was designed to maximize the inductive peaking effect using stack structure. Total twelve inductors of $100{\mu}m^2$ area increase was used. The measurement was processed on wafer and 1:2 demultiplexer with and without micro stacked spiral inductors were compared. For 6Gbps data rate measurement, eye width was improved 7.27% and Jitter was improved 43% respectively. Power consumption was 76.8mW and eye height was 180mV at 6 Gbps

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.8
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• pp.543-548
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• 2003

In this paper, we have proposed and fabricated a two-axis rotational micro-mirror with large tilt angle. Such a micro-mirror is a key element for N$\times$N high capacity optical cross-connect switches. The micro-mirror is required to have large tilt angle to increase the capacity of the cross-connect switches. For larger micro-mirror tilt angle between the grounded mirror plate and the bottom electrode is to be large enough to provide space for the tilting of the mirror. For our proposed structure, the gap was produced in such a way that the grounded mirror plate and the bottom electrode were made separately in different substrates by using the bulk micromachining technology, and combined later by employing self-align technique. As a result, a large tilt angle has been achieved without using additional actuators. The measured tilt angles were as large as $\pm$5.5$^{\circ}$ and $\pm$8.4$^{\circ}$ in the x and y direction respectively, and the pull-in voltages for the two directions were 380 V and 275 V respectively. Finally the fabricated mirror was successfully utilized to steer the optical beam. To our knowledge, our micro-mirror has the best performance among the micro-mirrors reported internationally so far.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.349-350
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• 2009