• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.573-574
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• 2006

The planarization technology of Chemical-mechanical polishing(CMP), used for the manufacturing of multi-layer various material interconnects for Large-scale Integrated Circuits (LSI), is also readily adaptable as an enabling technology in MicroElectroMechanical System (MEMS) fabrication, particularly polysilicon surface micromachining. However, general LSI device CMP has partly distinction aspects, the pattern scale and material sorts in comparison with MEMS CMP. This study performed preliminary CMP tests to identify slurry characteristic used in general IC device. The experiment result is possible to verify slurry characteristic in MEMS structure material.

• 한국전자파학회논문지
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• 제21권4호
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• pp.381-391
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• 2010

본 논문에서는 상용 초고주파 MEMS 스위치를 이용하여 세 개의 주파수 대역에서 재구성 동작이 가능한 주파수 재구성 능동 배열 안테나 시스템(Reconfigurable Active Array Antenna System: RAA System)을 제안하였다. MEMS 스위치는 삽입 손실 및 선형성 특성이 우수하고 격리도가 높아 주파수 재구성 시스템 구현 시, 재구성을 위한 스위치로 인한 성능 열화가 거의 없다는 장점이 있다. 제안된 주파수 재구성 능동 배열 안테나 시스템은 간단한 구조의 임피던스 매칭 회로(Reconfigurable impedance Matching Circuit: RMC)를 갖는 주파수 재구성 증폭기(Reconfigurable Front-end Amplifier: RFA)가 집적화 되어 있으며, 안테나 방사체(Reconfigurable Antenna Element: RAE)와 재구성 제어 보드(Reconfiguration Control Board: RCB)로 구성되어 있다. 본 논문에서 제안한 RAA 시스템은 850 MHz, 1.9 GHz, 3.4 GHz의 세 개 주파수로 재구성되어 동작하며, 안테나 방사체는 $2{\times}2$ 배열을 가지고 각각의 방사체는 광대역 다이폴 형태를 갖는다. 제작된 RAA 시스템은 실험을 통하여 그 타당성을 확인하였다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.271-275
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• 2006

This paper describes the design and realization of full attitude system based on MEMS IMU and GPS carrier phase. The work can be divided into two parts: First, initial heading is determined by using two GPS receivers. And this paper discusses the usage of space geometry conditions to reduce the range of ambiguity search. The method presented in this paper was tested on the static. On the static condition, an accuracy better than 0.06 degrees for heading for 3.48m long baseline has been achieved. Integration of GPS and low cost MEMS IMU are used to realize the real-time heading attitude system. Second, level attitude (pitch and roll) is determined using the method of frequency-velocity for the feedback control. At the same time, the method using the attitude based on MEMS IMU to help determination of the range of ambiguity search is proposed. The results done on the sea show that an alternative means to provide real-time, cost-effective, accurate and reliable attitude information for attitude surveys. Though motivated by a big ships application, the design can be applied to other vehicles.

• 한국공간구조학회논문집
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• 제18권4호
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• pp.49-59
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• 2018

Wireless sensors are more favorable in measuring structural response compared to conventional sensors. This is because they are easier to use with no issues with cables and are considerably cheaper. There are several applications that can be used in recording and analyzing data from MEMS sensor installed on an iPhone. The Vibration App is one of the applications used and there has not been adequate research conducted in analyzing the performance of this App. This paper analyzed the performance of the Vibration App by comparing it with the performance of an ICP sensor. Results show that natural frequency results are more accurate (error less than 5%) in comparison to the amplitude results. This means that built- in MEMS sensor in smartphones are good at estimating natural frequency of structures. In addition, it was seen that the results became more accurate at higher frequencies (5.0Hz and 10.0Hz).

• 한국공간구조학회논문집
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• 제19권2호
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• pp.63-72
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• 2019

Wireless sensors are more favorable in measuring structural response compared to conventional sensors in terms of them being easier to use with no issues with cables and them being considerably cheaper. Previous tests have been conducted to analyze the performance of MEMS (Micro Electro Mechanical Systems) sensor in sinusoidal excitation tests. This paper analyzes the performance of in-built MEMS sensors in devices by comparing with an ICP sensor as the reference. Earthquake input amplitude excitation in shaking table tests was done. Results show that MEMS sensors are more accurate in measuring higher input amplitude measurements which range from 100gal to 250gal than at lower input amplitudes which range from 10gal to 50gal. This confirms the results obtained in previous sinusoidal tests. It was also seen that natural frequency results have lower error values which range from 0% to 3.92% in comparison to the response spectra results. This also confirms that in-built MEMS sensors in mobile devices are good at estimating natural frequency of structures. In addition, it was also seen that earthquake input amplitudes with more frequency contents (Gyeongju) had considerably higher error values than Pohang excitation tests which has less frequency contents.

• 한국소음진동공학회논문집
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• 제18권4호
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• pp.458-464
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• 2008

The structural health monitoring has been gaining more importance in civil engineering areas such as earthquake and wind engineering. The use of health monitoring system can also provide tools for the validation of structural analytical model. However, only few structures such as historical buildings and some important long bridges have been instrumented with structural monitoring system due to high cost of installation, long and complicated installation of system wires. In this paper, the structural monitoring system based on cheap and wireless monitoring system is investigated. The use of advanced technology of micro-electro-mechanical system(MEMS) and wireless communication can reduce system cost and simplify the installation. Further the application of wireless MEMS system can provide enhanced system functionality and due to low noise densities. Identification results are compared to ones using data measured from traditional accelerometers and results indicate that the system identification using wireless MEMS system estimates system parameters accurately.

• JSTS:Journal of Semiconductor Technology and Science
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• 제7권3호
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• pp.177-182
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• 2007

This paper presents the see-saw type RF MEMS switch based on a single crystalline silicon structure with narrow gap vertical comb. Low actuation voltage and high isolation are key features to be solved in electrostatic RF MEMS switch design. Since these parameters in conventional parallel plate RF MEMS switch designs are in trade-off relationship, both requirements cannot be met simultaneously. In the vertical comb design, however, the actuation voltage is independent of the vertical separation distance between the contact electrodes. Therefore, the large separation gap between contact electrodes is implemented to achieve high isolation. We have designed and fabricated RF MEMS switch which has 46dB isolation at 5GHz, 0.9dB insertion loss at 5GHz and 40V actuation voltage.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 하계종합학술대회 논문집(2)
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• pp.335-338
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• 2004

We suggest Q-band MEMS MIMIC (Millimeter wave Monolithic Integrated Circuit) HEMT Oscillator using DAML (Dielectric-supported Airgapped Mcrostrip Line) structure. We elevated the signal lines from the substrate using dielectric post, in order to reduce the substrate dielectric loss and obtain low losses at millimeter-wave frequency. These DAML are composed with heist of $10\;{\mu}m$ and post size with $20\;{\mu}m\;{\times}\;20\;{\mu}m$. The MEMS oscillator was successfully integrated by the process of $0.1\;{\mu}m$ GaAs PHEMTs, CPW transmission line and DAML. The phase noise characteristic of the MEMS oscillator was improved more than 7.5 dBc/Hz at a 1 MHz offset frequency than that of the CPW oscillator And the high output power of 7.5 dBm was measured at 34.4 GHz.

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2000년도 Proceedings of 5th International Joint Symposium on Microeletronics and Packaging
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• pp.29-33
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• 2000

MEMS, Micro Electro-Mechanical Systems, present one of the greatest advanced packaging challenges of the next decade. Historically hybrid technology, generally thick film, provided sensors and actuators while integrated circuit technologies provided the microelectronics for interpretation and control of the sensor input and actuator output. Brought together in MEMS these technical fields create new opportunities for miniaturization and performance. Integrated circuit processing technologies combined with hybrid design systems yield innovative sensors and actuators for a variety of applications from single crystal silicon wafers. MEMS packages, far more simple in principle than today's electronic packages, provide only physical protection to the devices they house. However, they cannot interfere with the function of the devices and often must actually facilitate the performance of the device. For example, a pressure transducer may need to be open to atmospheric pressure on one side of the detector yet protected from contamination and blockage. Similarly, an optical device requires protection from contamination without optical attenuation or distortion being introduced. Despite impediments such as package standardization and complexity, MEMS markets expect to double by 2003 to more than ＄9 billion, largely driven by micro-fluidic applications in the medical arena. Like the semiconductor industry before it. MEMS present many diverse demands on the advanced packaging engineering community. With focused effort, particularly on standards and packaging process efficiency. MEMS may offer the greatest opportunity for technical advancement as well as profitability in advanced packaging in the first decade of the 21st century! This paper explores MEMS packaging opportunities and reviews specific technical challenges to be met.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.481-482
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• 2006

Chemical-mechanical polishing, the dominant technology for LSI planarization, is trending to play an important function in micro-electro mechanical systems (MEMS). However, MEMS CMP process has a couple of different characteristics in comparison to LSI device CMP since the feature size of MEMS is bigger than that of LSI devices. Preliminary CMP tests are performed to understand material removal rate (MRR) with blanket wafer under a couple of polishing pressure and velocity. Based on the blanket CMP data, this paper focuses on the consumable approach to enhance MEMS CMP by the adjustment of slurry and pad. As a mechanical tool, newly developed microstructured (MS) pad is applied to compare with conventional pad (IC 1400-k Nitta-Haas), which is fabricated by micro melding method of polyurethane. To understand the CMP characteristics in real time, in-situ friction force monitoring system was used. Finally, the topography change of poly-si MEMS structures is compared according to the pattern density, size and shape as polishing time goes on.