• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2006년도 춘계학술발표논문집
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• pp.223-226
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• 2006

The micro-gas sensor based on carbon nanotubes (CNTs) was fabricated and its gas sensing characteristics on nitrogen dioxide ($NO_2$) have been investigated. The sensor consists of a heater, an insulating layer, a pair of contact electrodes, and CNT-sensing film on a micromachined diaphragm. The heater plays a role in the temperature change to modify sensor operation. Gas sensor responses of CNT-film to $NO_2$ at room temperature are reported. The sensor exhibits a reversible response with a time constant of a few minutes at thermal treatment temperature of $130^{\circ}C$.

• 마이크로전자및패키징학회지
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• 제17권2호
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• pp.55-61
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• 2010

탄탈륨실리사이드 히터가 내장된 소자를 Ag 페이스트와 Au SBB(Stud Bump Bonding)를 이용하여 Au가 코팅 된 기판에 각각 접합 하였다. 전단 테스트와 전류를 흐르면서 열 성능을 측정하였다. Au 스터드 범프 본딩의 최적 플립칩 접합조건은 전단 후 파괴면 관찰하여 설정하였으며, 기판 온도를 $350^{\circ}C$, 소자 온도를 $250^{\circ}C$에서 하중을 300 g/bump 로 하여 접합하는 경우가 최적 조건이였다. 히터에 5 W 인가시 소자의 온도는 Ag 페이스트를 이용한 접합의 경우 최대 온도는 약 $50^{\circ}C$이었으며, Au 금속층을 갖고 있는 실리콘 기판에 Au 스터드 본딩으로 접합된 인 경우 약 $64^{\circ}C$를 나타내었다. 기판과의 접촉면적이 와이어본딩과 Au 스터드 범프 본딩 가 약 300배가 차이가 나는 경우 약 $14^{\circ}C$ 차이를 나타내었고, 전사모사를 통하여 접합면의 접촉저항이 중요한 이유임을 알 수 있었다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1196-1200
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• 2004

Micropump is very useful component in micro/nano fluidics and bioMEMS applications. In this study, a bubble-powered micropump was fabricated and tested. The micropump consists of two-parallel micro line heaters, a pair of nozzle-diffuser flow controller and a 1 mm in diameter, 400 ${\mu}m$ in depth pumping chamber. The two-parallel micro line heaters with 20 ${\mu}m-width$ and 200 ${\mu}m-length$ were fabricated to be embedded in the silicon dioxide layer of a wafer which serves as a base plate for the micropump. The pumping chamber, the pair of nozzle-diffuser unit and microchannels including the liquid inlet and outlet port were fabricated by etching through another silicon wafer. A glass wafer (thickness of $525{\pm}15$ ${\mu}m$) having two holes of inlet and outlet ports of liquid serve as upper plate of the pump. Finally the silicon wafer of the base plate, the silicon wafer of pumping chamber and the glass wafer were aligned and bonded (Si-Si bonding and anodic bonding). A sequential photograph of bubble nucleation, growth and collapse was visualized by CCD camera. Clearly liquid flow through the nozzle during the period of bubble growth and slight back flow of liquid at the end of collapsing period can be seen. The mass flow rate was found to be dependent on the duty ratio and the operation frequency. As duty ratio increases, flow rate decreases gradually when the duty ratio exceeds 60%. Also as the operation frequency increases, the flow rate of the micropump decreases slightly.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 G
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• pp.2544-2546
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• 1998

The electrical and physical charateristics of Pt-Co alloy thin films on $Al_2O_3$ substrate, deposited by r.f cosputtering respectively, were analyzed with thickness of thin films ($1700{\sim}10000{\AA}$) and increasing annealing temperature ($800{\sim}1000^{\circ}C$). At input power of Pt : 4.4 W/$cm^2$, Co : 6.91 W/$cm^2$, working vacuum of 10 mTorr and annealing conditions of $1000^{\circ}C$) and 60 min, the resistivity and sheet resistivity of Pt-Co thin films with thickness of $3000{\AA}$ was $15{\mu}{\Omega}{\cdot}cm$ and 0.5 ${\Omega}/{\square}$, respectively. The TCR value of Pt-Co alloy thin films was measured with various thickness of thin films and annealing conditions. The optimum TCR value of 3850 ppm/$^{\circ}C$ in temperature range($200{\sim}400^{\circ}C$) is gained under conditions $3000{\AA}$ of thin films thickness and $1000^{\circ}C$ of annealing temperature. The thermal charateristics of Pt-Co micro heaters were analysed with Pt-Co RTD integrated on the same substrate. In the analysis of characteristics of Pt-Co micro heaters, the Pt-Co micro heaters with thickness of $3000{\AA}$ and annealing temperature of $1000^{\circ}C$ had a good linearity and temperature is up to $468.2^{\circ}C$ with 2.1 watts of the heating power.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전기물성,응용부문
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• pp.45-48
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• 2003

In the research of proteomics, mass spectrometry analysis is the essential method for identification of the unknown proteins. Trypsin treatment for the sample preparation of mass spectrometry is the inevitable procedure[1]. However, sample preparation procedure is cumbersome and time consuming. To resolve these problems, Temperature controllable microreactor was designed and fabricated. It consists of metering chamber, micro channel, reaction chamber, platinum (Pt) thin film heater and a temperature sensor so that micro metering and mixture of reagent with temperature control can be done on the same chip. The total size of the fabricated microreactor was $37{\times}30{\times}1\;mm^3$ and the size of channel cross section was $200{\times}100{\mu}m^2$. PID temperature controller was realized using NI DAQ, PCI-MIO-l6E-1 board and LabVIEW program.

• 센서학회지
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• 제20권6호
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• pp.363-367
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• 2011

This paper proposes a highly-sensitive gas flow sensor with a simple structure. The sensor is composed of a micro-heater for heating the gas medium and a pair of temperature sensors for detecting temperature differences due to gas flow in a sealed chamber on one axis. Operation of the gas flow sensor depends on the transfer of heat through the air medium. The proposed gas flow sensor has the capability to measure gas flow rates <5 $cm^3$/min with a resolution of approximately 0.01 $cm^3$/min. Furthermore, this paper reports some additional experiment results, including the sensitivity of the proposed gas flow sensor as a function of operating current and the flow of different types of gas(oxygen, carbon dioxide, and nitrogen). The fabrication process of the proposed sensor is very simple, making it a good candidate for mass production.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권2호
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• pp.88-92
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• 2006

We present a microfluidic system with microvalves and a micropump that are easily integrated on the same substrate using the same fabrication process. The fabricated microfluidic system is suitable for use as a disposable device and its characteristics are optimized for use as a micro chemical analysis system (micro-TAS) and lab-on-a-chip. The system is realized by means of a polydimethylsiloxane (PDMS)-glass chip and an indium tin oxide (ITO) heater. We demonstrate the integration of the micropump and microvalves using a new thermopneumatic-actuated PDMS-based microfluidic system. A maximum pumping rate of about 730 nl/min is observed at. a duty ratio of 1 $\%$ and a frequency of 2 Hz with a fixed power of 500 mW. The measured power at flow cut-off is 500 mW for the microvalve whose channel width, depth and membrane thickness were 400 $\mu$m, 110 $\mu$m, and 320 $\mu$m, respectively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전기물성,응용부문
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• pp.57-59
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• 2002

기존에 연구된 미세 가열기를 이용한 마이크로 시스템 패키징의 문제점을 해결하기 위해 새로운 미세 가열기를 제작하여 접합 실험을 실시하였다. 기존 형상의 미세 가열기와 새로운 미세 가열기의 형상을 각각 제작하여 접합시 미세 가열기에 발생하는 열분포를 IR 카메라를 이용하여 실험하였으며, 기존 형상의 미세 가열기가 불균일하게 가열되는 반면, 새로운 형상의 미세 가열기는 매우 균일하게 가열되는 형상을 나타내었다. 카메라 실험 결과를 바탕으로 접합 실험을 실시하기 위해서 폭 $50{\mu}m$, 두께 $2{\mu}m$의 미세 가열기를 제작하였으며, 0.2 Mpa의 압력을 Pyrex glass cap에 가한 상태에서 150 mA의 전류를 공급함으로서 접합을 완료하였다. 접합이 완료된 시편들에 대해서 IPA를 통한 leak 실험을 실시하였으며, 기존 형상의 미세 가열기를 이용한 시편들은 66%가 테스트를 통과한 반면 새로운 형상의 미세 가열기를 이용한 시편들은 85%이상이 테스트를 통과하였다. Leak 실험을 통과한 각각의 시편들에 대해서 접합력 측정을 실시한 결과, 기존 형상의 미세 가열기를 이용한 시편들은 $15{\sim}21$ Mpa의 접합력을 나타내었고, 새로울 형상의 미세 가열기를 이용한 시편들은 $25{\mu}30$ Mpa의 우수한 접합력을 나타내었다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제5권3호
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• pp.149-158
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• 2005

This paper describes design, fabrication, and application of the silicon based temperature controllable micro reactor. In order to achieve fast temperature variation and low energy consumption, reaction chamber of the micro reactor was thermally isolated by etching the highly conductive silicon around the reaction chamber. Compared with the model not having thermally isolated structure, the thermally isolated micro reactor showed enhanced thermal performances such as fast temperature variation and low energy consumption. The performance enhancements of the micro reactor due to etched holes were verified by thermal experiment and numerical analysis. Regarding to 42 percents reduction of the thermal mass achieved by the etched holes, approximately 4 times faster thermal variation and 5 times smaller energy consumption were acquired. The total size of the fabricated micro reactor was $37{\times}30{\times}1mm^{3}$. Microchannel and reaction chamber were formed on the silicon substrate. The openings of channel and chamber were covered by the glass substrate. The Pt electrodes for heater and sensor are fabricated on the backside of silicon substrate below the reaction chamber. The dimension of channel cross section was $200{\times}100{\mu}m^{2}$. The volume of reaction chamber was $4{\mu}l$. The temperature of the micro reactor was controlled and measured simultaneously with NI DAQ PCI-MIO-16E-l board and LabVIEW program. Finally, the fabricated micro reactor and the temperature control system were applied to the thermal denaturation and the trypsin digestion of protein. BSA(bovine serum albumin) was chosen for the test sample. It was successfully shown that BSA was successfully denatured at $75^{\circ}C$ for 1 min and digested by trypsin at $37^{\circ}C$ for 10 min.

• Progress in Superconductivity
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• 제14권2호
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• pp.102-105
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• 2012

We are developing meander-shaped metallic magnetic calorimeters using micro-fabrication methods. A planar Nb coil in a meander shape was fabricated on a Si substrate. The coil was designed to have a persistent current using a metal heater evaporated on a part of the coil. A paramagnetic sensor, $5{\mu}m$ thick Au:Er foil, was glued on top of the meander structure with epoxy. The magnetization and heat capacity were measured at different temperatures, and applied field currents matched well with expected values. The detector showed an energy resolution of 4 keV FWHM for the 5.5 MeV alpha particles.