양극접합에 의한 실리콘과 글라스 기판의 직접접합

정귀상,김한근 동서대학교 부설 연구소 1996 연구소 논문집 Vol.1 No.-

Anodic bonding is a key technology for micromechanical components. One major advantage with this method is the strong electrostatic forces obtained during bonding. These forces serve to pull the two surfaces together thereby minimising the unbonded areas around contaminated spots. In this paper, the bonding was performed at temperatures ranging from 300 to 450℃, voltages 400 to 1000 V and times 10 to 30 minutes. The sizes of the Si and the Pyrex #7740 glass were 6 mm×6 mm, respectively. Bonding processes and interfaces were observed by the optical microscope and SEM. Optimum condition of the anodic bonding was at temperature above 400℃ without regard to voltage.

HF 전처리시 SDB의 초기접합에 관한 연구

정귀상,강경두 東西大學校 1999 동서논문집 Vol.5 No.-

Si direct bonding(SDB) technology is very attractive for both Si-on-insulator(SOI) electric devices and MEMS applications because of its stress free structure and stability. This paper presents on pre-bonding according to HF pre-treatment conditions in Si wafer direct bonding. The characteristics of bonded sample were measured under different bonding conditions of HF concentration, applied pressure and annealing temperature(200∼1000℃ ) after pre-bonding. The bonding strength was evaluated by tensile strength method. The bonded interface and the void were analysed by using SEM and IR camera, respectively Components existed in the interlayer were analyzed by using FT-IR. The bond strength depends on the HF pre-treatment condition before pre-bonding (Min : 2.4kgf/㎠∼Max : 14.7kgf/㎠)

수용성 TMAH 암모니아계를 이용한 실리콘 이방성 식각

정귀상,송승환,박진성,최영규 동서대학교 부설 연구소 1996 연구소 논문집 Vol.1 No.-

Si anistropic etching is a key technology for micromachining. The main advantages of teramethyl ammonium hydroxide (TMAH)-based solution are their full compatibility with IC process. In this paper, the anisotropic etching characteristics of single crystal Si in a TMAH ((CH??)??NOH) based solution was described. The influence of the adition of IPA to TMAH solution on their etching characteristics was also presented. The etching rate ratio of Si (111)/(100) is increased with increasing TMAH concentration. The addition of IPA to TMAH solution leads to smoother furfaces of sidewalls etched planes and reduce undercutting ratio by a factor of 2-3. Finally, the p?? Si anisotropic etching characteristics by means of heavily boron doping was investigated.

전기화학적 식각정지법에 의한 고수율 압저항향 마이크로 압력센서의 제작

정귀상,박진성 東西大學校 1999 동서논문집 Vol.5 No.-

This paper presents the fabrication of high-yield piezoresistive micro pressure sensors by electrochemical etch-stop method in TMAH/IPA/pyrazine solution. Addition of pyrazine to TMAH etchants increases the etch rates of (100) Si, thus the elapsed time for etch-stop was shortened. I-V curves of n and p-type Si in TMAH/IPA/pyrazine solution were obtained. Diaphragms having 20 ㎛ thick were fabricated in 5-inch wafer. The thicknesses of diaphragms were measured and thickness variations were also checked. Piezoresistive pressure sensors using these diaphragms were fabricated by micromachining technology with a standard IC process. The diaphragm thickness is precisely controlled by electrochemical etch-stop method. The pressure sensitivity variation across a 5-inch Si wafer of 5% was obtained.

마그네트론 코스퍼터링에 의한 측온저항체 온도센서용 Pt-Co 합금박막의 증착과 그 특성

정귀상,김서연,노상수 東西大學校 1997 동서논문집 Vol.3 No.1

Plantinum-Cobalt alloy thin films were deposited on Al₂O₃ substrate by cosputtering for RTD(Resistance Thermometer Devices) temperature sensors. We made Pt-Co alloy resistance patterns on the Al₂O₃substrate by lift-off method and investigated the physical and electrical characteristics of these films under various conditions, the input power, working vacuum, annealing temperature and time, and also after annealing these films. The resistivity and sheet resistivity of these films were decreased with increasing the annealing temperature. After the annealing treatment at 800℃ for 60 min, the resistivity and sheet resistivity of Pt-Co thin films was 15μΩ·cm and 0.5Ω/□, respectively and the TCR value of Pt-Co alloy thin films with thickness of 3000Å was 3740 ppm/℃ in the temperature range of 25∼400℃. These results indicate that Pt-Co alloy thin films have potentiality for the RTD temperature sensors.

크롬질화박막형 스트레인 게이지의 제작

정귀상,서정환 東西大學校 1999 동서논문집 Vol.5 No.-

This paper presents characteristics of CrN thin-film strain gauges, which were deposited on glass by DC reactive magnetron sputtering in an argon-nitrogen atmosphere(Ar-(5-25 %)N₂). The physical and electrical characteristics of these films investigated with the thickness range 3500Å of CrN thin-films, annealing temperature (100∼300℃) and annealing time (24∼72 hr). The optimized condition of CrN thin-film strain gauges were thickness range of 3500Å and annealing condition(300℃, 48 hr) in Ar-10 % N₂ deposition atmosphere. Under optimum conditions, the CrN thin-films for strain gauge is obtained a high resistivity, ρ =1147.65 μΩcm, a low temperature coefficient of resistance, TCR=-186 ppm/℃ and a high temporal stability with a good longitudinal, 11.17. And change in resistance after annealing for the CrN thin-films were quitely linear and stable.

고속응답, 저소비전력형 마이크로 유량센서의 제작과 그 특성

정귀상,홍석우 東西大學校 2000 동서논문집 Vol.6 No.-

This paper describes on the fabrication and characteristics of hot-film type micro-flowsensors integrated with Pt-RTD's and micro-heaters on the Si substrate, in which MgO thin-films were used as medium lager in order to improve adhesion of Pt thin-films to SiO2 layer. The MgO layer improved adhesion of Pt thin-films to SiO2 layer without any chemical reactions to Pt thin-films under high annealing temperatures. In investigating output characteristics of the fabricated micro-flowsensors, the output voltages increased as gas flow rate and its conductivity increased due to increase of heat-loss from sensor to external. Output voltage was 82 mV at N2 flow rate of 2000 sccm/min, heating power of 1.2W.

SDB와 전기화학적 식각정지에 의한 마이크로 시스템용 매몰 cavity를 갖는 SOI구조의 제조

정귀상 東西大學校 2001 동서논문집 Vol.7 No.-

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-wafe 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 maked on the upper handing wafer by Si anisotropic etching. Two wafers are bonded with an intermediate insulating oxide layer. After high-temperature annaling (1000℃, 60 min.), the SBB SOI structure with buried cavities was thinned by electrochemical etch-stop. The surface of the fabricated SDB SOI structure is more uniform that of gliding or polishing by mechanical method. This SBB SOI structure with buried cavities will provides a powerful and versatile substrate for novel microsensors and microactuators.

마이크로시스템용 SDB SOI구조의 제작

정귀상,강경두 東西大學校 2000 동서논문집 Vol.6 No.-

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.

극한 환경 MEMS용 3C-SiC 박막의 결정 특성

정수용,정연식,류지구,정귀상,Shigehiro, Nishino 경북대학교 센서기술연구소 2002 센서技術學術大會論文集 Vol.13 No.1