맴브레인 구조를 이용한 미세발열체형 유량센서의 제작과 그 특성

정귀상,노상수 한국전기전자재료학회 1998 전기전자재료학회논문지 Vol.11 No.11

This paper describes the characteristics of Pt microheater using aluminum oxide films as medium layer and its application to flow sensors. Pt microheater have heating temperature of $390^{\circ}C$ at heating power of 1.2 W. Output voltages of flow sensors which were fabricated by integrating sensing-part with heating-part increase as gas flow rate and its conductivity increase. At $O_2$ flow rate of 2000 sccm, heating power of 0.8 W, output voltage of flow sensor is 101 mV under bridge-applied voltage of 5 V.

금속박막형 압력세서의 제작과 그 특성

정귀상,최성규,남효덕,이원재,송재성 한국전기전자재료학회 2001 전기전자재료학회논문지 Vol.14 No.5

This paper describes fabrication and characteristics of metal thin-film pressure sensor for working at high temperature. The proposed pressure consists of a chrom thin-film, patterned on a Wheat stone bridge configuration, sputter-deposited onto thermally oxidized Si membranes with an aluminium interconnection layer. The fabricated pressure sensor presents a low temperature coefficient of resistance, high-sensitivity, low non-linearity and excellent temperature stability. The sensitivity is 1.097∼1.21mV/V$.$kgf/$\textrm{cm}^2$ in the temperature range of 25∼200$^{\circ}C$ and the maximum non-linearity is 0.43%FS.

SDB와 전기화학적 식각정지에 의한 벌크 마이크로머신용 3차원 미세구조물 제작

정귀상,김재민,윤석진 한국전기전자재료학회 2002 전기전자재료학회논문지 Vol.15 No.11

This paper reports on the fabrication of free-standing microstructures by DRIE (deep reactive ion etching). SOI (Si-on-insulator) structures with buried cavities are fabricated by SDB (Si-wafer direct bonding) technology and electrochemical etch-stop. The cavity was formed the upper handling wafer by Si anisotropic etch technique. SDB process was performed to seal the formed cavity under vacuum condition at -760 mmHg. In the SDB process, captured air and moisture inside of the cavities were removed by making channels towards outside. After annealing (100$0^{\circ}C$, 60 min.), the SDB SOI structure with a accurate thickness and a good roughness was thinned by electrochemical etch-stop in TMAH solution. Finally, it was fabricated free-standing microstructures by DRIE. This result indicates that the fabrication technology of free-standing microstructures by combination SDB, electrochemical etch-stop and DRIE provides a powerful and versatile alternative process for high-performance bulk micromachining in MEMS fields.

SDB와 전기화학적 식각정지에 의한 마이크로 시스템용 매몰 공동을 갖는 SOI 구조의 제조

정귀상,강경두,최성규 한국센서학회 2002 센서학회지 Vol.11 No.1

This paper describes a new process technique for batch fabrication of SOI(Si-on-insulator) structures with buried cavities for MEMS(Micro electro mechanical system) applications by SDB(Si-wafer direct bonding) technology and electrochemical etch-stop. A low-cost electrochemical etch-stop method is used to control accurately the thickness of SOI. The cavities were made on the upper handling wafer by Si anisotropic etching. Two wafers are bonded with an intermediate insulating oxide layer. After high-temperature annealing(1000℃, 60 min.), the SDB SOI structure with buried cavities was thinned by electrochemical etch-stop. The surface of the fabricated SDB SOI structure have more roughness that of lapping and polishing by mechanical method. This SDB SOI structure with buried cavities will provide a powerful and versatile substrate for novel microsensors and microactuators. 본 논문은 Si기판 직접접합기술과 전기화학적 식각정지를 이용하여 마이크로 시스템용 매몰 공동을 갖는 SOI 구조물의 일괄제조에 대한 새로운 공정기술에 관한 것이다. 저비용의 전기화학적 식각정지법으로 SOI의 정확한 두께를 제어하였다. 핸들링 기판 위에서 Si 이방성 습식식각으로 공동을 제조하였다. 산화막을 갖는 두 장의 Si기판을 직접접합한 후, 고온 열처리(1000℃, 60분)를 시행하고 전기화학적 식각정지로 매몰 공동을 갖는 SDB SOI 구조를 박막화하였다. 제조된 SDB SOI 구조물 표면의 거칠기는 래핑과 폴리싱에 의한 기계적인 방법보다도 우수했다. 매몰 공동을 갖는 SDB SOI 구조는 새로운 마이크로 센서와 마이크로 엑츄에이터에 대단히 효과적이며 다양한 응용이 가능한 기판으로 사용될 것이다.

Si(100)기판위에 성장된 3C-SiC 박막의 반응성 이온식각 특성

정귀상,정수용,Shigehira Nishino 한국전기전자재료학회 2004 전기전자재료학회논문지 Vol.17 No.7

This paper describes on RIE(Reactive Ion Etching) characteristics of 3C-SiC(Silicon Carbide) grown on Si(100) wafers. In this work, CHF$_3$ gas was used to form the polymer as a function of a side-wall for excellent anisotropy etching during the RIE process. The ranges of the etch rate were obtained from 60 $\AA$/min to 980 $\AA$/min according to the conditions such as working gas pressure, RF power, distance between electrodes and the $O_2$ addition ratio in working gas pressure. Under the condition such as 100 mTorr of working gas pressure, 200 W of RF power and 30 mm of the distance between electrodes, mesa structures with about 40 of the etch angle were formed, and the vertical structures could be improved with 50 % of $O_2$ addition ratio in reactive gas during the RIE process. As a result of the investigation, we know that it is possible to apply the RIE process of 3C-SiC using CHF$_3$ for the development of electronic parts and MEMS applications in harsh environments.

NOVEL PRESSURE SENSOR SUITABLE FOR ULTRA-STABLE HIGH-TEMPERATURE AND HIGH-RESOLUTION USING SOI TECHNOLOGY

정귀상,Shoji Kawahito,Makato Ishida,Tetsuro Nakamura,최세곤 대한전자공학회 1990 대한전자공학회 학술대회 Vol.1990 No.7

측온저항체 온도센서용 백금박막의 형성에 관한 연구

정귀상,노상수 한국전기전자재료학회 1996 電氣電子材料學會誌 Vol.9 No.9

Platinum thin films were deposited on Si-wafer by DC rnagnetron sputtering for RTD (resistance thermometer devices). We investigated the physical and electrical characteristics of these films under various conditions, the input power, working vacuum, temperature of substrate and also after annealing these films. The deposition rate was increased with increasing the input power but decreased with increasing Ar gas pressure. The resistivity and sheet resistivity were decreased with increasing the temperature of substrate and the annealing time at 1000.deg. C. At substrate temperature of >$300^{\circ}C$, input power of 7 w/cm$^{2}$, working vacuum of 5 mtorr and annealing conditions of 1000.deg. C and 240 min, we obtained 10.65.mu..ohm..cm, resistivity of Pt thin films and 3800-3900 ppm/.deg. C, TCR(temperature coefficient of resistance). These values are close to the bulk value. These results indicate that the Pt thin films deposited by DC magnetron sputtering have potentiality for the development of Pt RTD temperature sensor.

측온저항체 온도센서가 집적화된 발열저항체형 마이크로 유량센서의 제작 및 특성

정귀상,홍석우 한국전기전자재료학회 2000 전기전자재료학회논문지 Vol.13 No.7

This paper describes on the fabrication and characteristics of hot-film type micro-flowsensors integrated with Pt-RTD(resistance thermometer device) and micro-heater on the Si membrane in which MgO thin-film was used as medium layer in order to improve adhesion of Pt thin-film to SiO$_2$layer. The MgO layer improved adhesion of Pt thin-film to SiO$_2$layer without any chemical reactions to Pt thin-film under high annealing temperatures. Output voltages increased due to increase of heat-loss from sensor to external. The output voltage was 82 mV at $N_2$flow rate of 2000 sccm/min heating power of 1.2 W. The response time($\tau$:63%) was about 50 msec when input flow was stepinput

전기화학적 식각정지에 의한 SDB SOI기판의 제작

정귀상,강경두 한국전기전자재료학회 2000 전기전자재료학회논문지 Vol.13 No.5

This paper describes on the fabrication of a SOI substrate by SDB technology and electrochemical etch-stop. The surface of the thinned SDB SOI substrate is more uniform than that of grinding or polishing by mechanical method and this process was found to be a very accurate method for SOI thickness control. During electrochemical etch-stop leakage current versus voltage curves were measured for analysis of the open current potential(OCP) point the passivation potential(PP) point and anodic passivation potential. The surface roughness and the controlled thickness selectivity of the fabricated a SDB SOI substrate were evaluated by using AFM and SEM respectively.

마이크로 압력센서의 기술동향

정귀상 한국전기전자재료학회 1995 電氣電子材料學會誌 Vol.8 No.1

일반적으로 단결정 실리콘은 거의 모든 전자소자의 재료로서 널리 사용되고 있으며 제조공정기술 또한 상당한 수준에 도달하고 있다. 최근에는 실리콘 자체의 우수한 압저항효과, 기계적 특성 그리고 반도체 제조공정을 이용한 미세가공기술인 마이크로머시닝을 이용하는 반도체 압력센서에 대한 연구가 활발히 진행되고 있다. 기계식 압력센서에 비해서 전기적 변화를 이용하는 반도체 압력센서에서는 소형, 저가격, 고신뢰성, 고감도, 다기능, 고분해, 고성능 및 집적화 등의 우수한 특성을 지니고 있다. 본고에서는 이러한 특성을 가지는 반도체 압력센서중 특히, 압저항형과 용량형 압력센서의 구조와 원리, 그리고 연구.개발동향 및 향후 전망에 관해서 기술하였다.