• Title/Summary/Keyword: Deep RIE

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A High Resolution Capacitive Single-Silicon Microaccelerometer using High Amplitude Sense Voltage for Application to Personal Information System (고 감지 전압을 이용한 개인 정보기기용 고정도 정전용량형 단결성 실리콘 가속도계)

  • Han, Ki-Ho;Cho, Young-Ho
    • Proceedings of the KSME Conference
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    • 2001.06c
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    • pp.53-58
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    • 2001
  • This paper presents a high resolution capacitive microaccelerometer for applications to personal information systems. We reduce the mechanical noise level of the microaccelerometer by increasing the proof-mass based on deep RIE process. We reduce the electrical noise level by increasing the amplitude of an AC sense voltage. The high sense voltage is obtained by DC-to-DC voltage multiplier. In order to solve the nonlinearity problem caused by the high sense voltage, we modify the conventional comb electrode of straight finger type into that of branched finger type, resulting in self force-balancing effects for enhanced detection linearity. The proposed branched finger capacitive microaccelerometer was fabricated by the deep RIE process of an SOI wafer. The fabricated microaccelerometer reduces the electrical noise at the level of $2.4{\mu}g/\sqrt{Hz}$ for the sense voltage of l6.5V, which is 10.1 times smaller than the electrical noise level of $24.3{\mu}g/\sqrt{Hz}$ at 0.9V. For the sense voltage higher than 2V, the electrical noise level of the microaccelerometer became smaller than the constant mechanical noise level of $11{\mu}g/\sqrt{Hz}$. Total noise level, including the electrical noise and the mechanical noise, has been measured as $9{\mu}g/\sqrt{Hz}$ for the sense voltage of 16.5V, which is 3.2 times smaller than the total noise of $28.6{\mu}g/\sqrt{Hz}$ for the sense voltage of 0.9V. The self force-balancing effect results in the increased stiffness of 1.98 N/m at the sense voltage of 17.8V, compared to the stiffness of 1.35 N/m at 0V, thereby generating the additional stiffness at the rate of $0.002N/m/V^{2}$.

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The Development of Cl-Plasma Etching Procedure for Si and SiO$_2$

  • Kim, Jong-Woo;Jung, Mi-Young;Park, Sung-Soo;Boo, Jin-Hyo
    • Journal of the Korean institute of surface engineering
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    • v.34 no.5
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    • pp.516-521
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    • 2001
  • Dry etching of Si wafer and $SiO_2$ layers was performed using He/Cl$_2$ mixture plasma by diode-type reactive ion etcher (RIE) system. For Si etching, the Cl molecules react with the Si molecules on the surface and become chemically stable, indicating that the reactants need energetic ion bombardment. During the ion assisted desorption, energetic ions would damage the photoresist (PR) and produce the bad etch Si-profile. Moreover, we have examined the characteristics of the Cl-Si reaction system, and developed the new fabrication procedures with a $Cl_2$/He mixture for Si and $SiO_2$-etching. The developed novel fabrication procedure allows the RIE to be unexpensive and useful a Si deep etching system. Since the etch rate was proved to increase linearly with fHe and the selectivity of Si to $SiO_2$ etch rate was observed to be inversely proportional to fHe.

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A Study for Characteristics of Water that Penetrates Wood Flour due to Changes of Concentration of BDG (BDG 농도변화에 따른 용수의 목분 침투특성 연구)

  • Kong, Il-Chean;Park, Il-Gyu;Lim, Kyung-Bum;Rie, Dong-Ho
    • Journal of the Korean Society of Safety
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    • v.28 no.3
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    • pp.74-79
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    • 2013
  • As the feature of fire, it is hard for deep-seated fire to spread to the deeper site, and it also has danger for being re-ignited cause of recontacting with oxygen after being put off. Now it is ruled in the certification criteria of wetting agent used for extinguishing deep-seated fire that the criteria for surface tension is below 33[mN/m] in Korea. For figuring out how much water for fire-fighiting can permeate into combustibles, in this research, the permeating performance is analyzed by measuring the speed of permeating and transmission quantity released after that, by pouring solution whose surface tension is changed by adjusting concentration of surfactant BDG(Butyl Di Glycol) in column From this result, it is can be determined that transmission quantity becomes less and wet area goes wider as surface tension is lower, and it is also able to be analyzed as quantity of absorbed liquid and wet area is increased because fluid permeates into the core.

Characteristics of a Coupled Gas Lubricated Bearing for a Scaled-Up Micro Gas Turbine

  • Lee, Yong Bok;Kwak, Hyunduck;Kim, Chang Ho;Jang, Gun Hee
    • KSTLE International Journal
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    • v.1 no.2
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    • pp.107-112
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    • 2000
  • In case of the limitation of Deep RIE fabrication far Micro Gas Turbine, bearing aspect ratio is limited in very small value. The characteristics such as pressure distribution, load capacity and non-linearity of a short bearing of L/D=0.083 and a conventional bearing of L/D=1.0 with coupled boundary effects are investigated for Micro Gas Turbine bearings. The coupled effect was analyzed by mass conservation at coupled end area. The results, increasing load capacity and non-linearity due to the coupled effect of thrust and journal bearing, are obtained and the selection of journal bearing type is discussed.

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Flow Behaviors of Polymers in Micro Hot Embossing Process (미세 핫엠보싱 공정에서 폴리머의 유동특성)

  • Ban Jun Ho;Shin Jai Ku;Kim Byeong Hee;Kim Heon Young
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.8 s.173
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    • pp.159-164
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    • 2005
  • The Hot Embossing Lithography(HEL) as a method fur the fabrication of the nanostructure with polymer is becoming increasingly important because of its simple process, low cost, high replication fidelity and relatively high throughput. In this paper, we carried out experimental studies and numerical simulations in order to understand the viscous flow of the polymer (PMMA) film during the hot embossing process. To grasp the characteristics of the micro patterning rheology by process parameters (embossing temperature, pressure and time), we have carried out various experiments by using the nickel-coated master fabricated by the deep RIE process and the plasma sputtering. During the hot embossing process, we have observed the characteristics of the viscoelastic behavior of polymer. Also, the viscous flow during the hot embossing process has been simulated by the continuum based FDM(Finite Difference Method) analysis considering the micro effect, such as a surface tension and a contact angle.

Development of Improved Fabrication Methods for 2-axis Electrically Levitated MEMS Gyroscope (2축 정전부양형 MEMS 자이로스코프의 향상된 제작 공정 개발)

  • Seok, Seyeong;Lim, Geunbae
    • Journal of Sensor Science and Technology
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    • v.24 no.4
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    • pp.274-279
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    • 2015
  • This paper describes optimizing fabrication methods for 2-axis electrically levitated MEMS gyroscope. Electrostatically levitated gyroscope has very high potential of performance due to the fact that its proof mass is not mechanically bound to any other structures, but its complex structure and difficulty of fabrication holds back the research that only a few researches have been reported. In this work, fabrication method for glass-silicon-glass 3-floor structure for 2-axis electrically levitated MEMS gyroscope is presented, including simplified multi-level glass etch method utilizing photoresist attack, preventing metal diffusion by adding middle layer of metal electrode, overcoming Deep RIE limitation by separate fabrication of silicon structures and keeping the electrode safe from dicing debris.

Characteristics silicon pressure sensor using dry etching technology (건식식각 기술 이용한 실리콘 압력센서의 특성)

  • Woo, Dong-Kyun;Lee, Kyung-Il;Kim, Heung-Rak;Suh, Ho-Cheol;Lee, Young-Tae
    • Journal of Sensor Science and Technology
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    • v.19 no.2
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    • pp.137-141
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    • 2010
  • In this paper, we fabricated silicon piezoresistive pressure sensor with dry etching technology which used Deep-RIE and etching delay technology which used SOI(silicon-on-insulator) wafer. We improved pressure sensor offset and its temperature dependence by removing oxidation layer of SOI wafer which was used for dry etching delay layer. Sensitivity of the fabricated pressure sensor was about 0.56 mV/V${\cdot}$kPa at 10 kPa full-scale, and nonlinearity of the fabricated pressure sensor was less than 2 %F.S. The zero off-set change rate was less than 0.6 %F.S.

Fabrication and Testing of a Polysilicon Piezoresistive Accelerometer using p+ Silicon Diaphragm (p+ 실리콘 박막을 이용한 폴리실리콘 압저항 가속도계의 제작 및 측정)

  • Yang, E.H.;Jeong, O.C.;Yang, S.S.
    • Proceedings of the KIEE Conference
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    • 1996.07c
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    • pp.1994-1996
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    • 1996
  • This paper presents the fabrication and testing of a polysilicon piezoresistive accelerometer with p+ silicon diaphragm by simple process such as two step photolithography for the RIE process to form the cantilevers and a deep anisotropic etch process for the complete fabrication of the accelerometer. The fabricated accelerometer consists of a seismic mass and four cantilevers on which polysilicon piezoresistors are formed. The measurement of the output signal from the bridge circuit of the fabricated accelerometer is carried out with the HP 3582A spectrum analyzer. The analysis of the experimental result is showed in terms of the sensitivity and the resonant frequency. At atmospheric condition, the measurement values of the sensitivity and the resonant frequency are $11\;{\mu}V/Vg$ and 475 Hz, respectively.

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The Effect of Micro Nano Multi-Scale Structures on the Surface Wettability (초소수성 표면 개질에 미치는 마이크로 나노 복합구조의 영향)

  • Lee, Sang-Min;Jung, Im-Deok;Ko, Jong-Soo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.32 no.5
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    • pp.424-429
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    • 2008
  • Surface wettability in terms of the size of the micro nano structures has been examined. To evaluate the influence of the nano structures on the contact angles, we fabricated two different kinds of structures: squarepillar-type microstructure with nano-protrusions and without nano-protrusions. Microstructure and nanostructure arrays were fabricated by deep reactive ion etching (DRIE) and reactive ion etching (RIE) processes, respectively. And plasma polymerized fluorocarbon (PPFC) was finally deposited onto the fabricated structures. Average value of the measured contact angles from microstructures with nanoprotrusions was $6.37^{\circ}$ higher than that from microstructures without nano-protrusions. This result indicates that the nano-protrusions give a crucial effect to increase the contact angle.

Reverse-Conducting IGBT Using MEMS Technology on the Wafer Back Side

  • Won, Jongil;Koo, Jin Gun;Rhee, Taepok;Oh, Hyung-Seog;Lee, Jin Ho
    • ETRI Journal
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    • v.35 no.4
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    • pp.603-609
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    • 2013
  • In this paper, we present a 600-V reverse conducting insulated gate bipolar transistor (RC-IGBT) for soft and hard switching applications, such as general purpose inverters. The newly developed RC-IGBT uses the deep reactive-ion etching trench technology without the thin wafer process technology. Therefore, a freewheeling diode (FWD) is monolithically integrated in an IGBT chip. The proposed RC-IGBT operates as an IGBT in forward conducting mode and as an FWD in reverse conducting mode. Also, to avoid the destructive failure of the gate oxide under the surge current and abnormal conditions, a protective Zener diode is successfully integrated in the gate electrode without compromising the operation performance of the IGBT.