• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04b
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• pp.112-116
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• 2000

This paper presents anisotropic ethcing characteristics of single-crystal silicon in tetramethylammonium hydroxide(TMAH):isopropyl alcohol(IPA) solutions containing pyrazine. With the addition of IPA to TMAH solutions, etching characteristics are exhibited that indicate an improvement in flatness on the etching front and a reduction in undercutting, but the etch rate on (100) silicon is decreased. The (100) silicon etch rate is improved by the addition of pyrazine. An etch rate on (100) silicon of $0.8\;{\mu}m/min$, which is faster by 13 % than a 20 wt.% solution of pure TMAH, is obtained using 20 wt.% TMAH:0.5 g/100 ml pyrazine solutions, but the etch rate on (100) silicon is decreased if more pyrazine is added. With the addition of pyrazine to a 25 wt.% TMAH solution, variations in flatness on the etching front were not observed and the undercutting ratio was reduced by 30 ~ 50 %.

• Transactions on Electrical and Electronic Materials
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• v.2 no.2
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• pp.21-25
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• 2001

This paper presents the effect of pyrazine on tetramethylammonium hydroxide (TMAH):isopropyl alcohol (IPA) single-crystal silicon anisotropic etching properties. With the addition of IPA to TMAH solutions, etching characteristics are exhibited an improvement in flatness on the etching front and a reduction in undercutting, but the etch rate on (100) silicon is decreased. The (100) silicon etch rate is improved by the addition of pyrazine. An etch rate on (100) silicon of 0.8 ${\mu}{\textrm}{m}$/min, which is faster by 13% than a 20 wt.% solution of pure TMAH, is obtained using 20 wt.% TMAH: 0.5 g/100 ml pyrazine solutions, but the etch rate on (100) silicon is decreased when more pyrazine is added. With the addition of pyrazine to a 25 wt.% TMAH solution, variations in flatness on the etching front are not observed and the undercutting ratio is reduced by 30~50%. These results indicate that anisotropic etching technology using TMAH:IPA:pyrazine solutions provides a powerful and versatile method for realizing of microelectromechanical systems.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.23-26
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• 1997

This work presents the TMAH/IPA anisotropic etching characteristics with addition of Pyrazine. (100) Si etching rate of 0.747 ${\mu}{\textrm}{m}$/min at 8$0^{\circ}C$ was obtained using TMAH 25 wt.% / IPA 17 vol.% / pyrazine 0.1 g. The etching rate of (100) Si is increased about 52% compare to pure TMAH 25 wt.%. But etching rate of (100) Si is decreased with increasing Pyrazine additive. Activation energy of TMAH/IPA/pyrazine is much lower than TMAH and TMAH/IPA solutions. Addition of Pyrazine does not effect on surface flatness and decreases undercutting ratio about 20 %. Therefore, TMAH/IPA/pyrazine is an attractive anisotropic etchant because of alkaline-ion free.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04b
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• pp.147-151
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• 2000

This paper presents the electrochemical etch-stop characteristics of single-crystal silicon in a tetramethyl ammonium hyciroxide(TMAH):isopropyl alcohol(IPA):pyrazine solution. Addition of pyrazine to a TMAH:IPA etchant increases the etch-rate of (100) silicon, thus the elapsed time for etch-stop was shortened. The current-voltage(I-V) characteristics of n- and p-type silicon in a TMAH:IPA:pyrazine solution were obtained, respectively. Open circuit potential(OCP) and passivation potential(PP) of n- and p-type silicon, respectively, were obtained and applied potential was selected between n- and p-type silicon PP. The electrochemical etch-stop is applied to the fabrication of 801 microdiaphragms having $20\;{\mu}m$ thickness on a 5-inch silicon wafer. The averge thicknesses of 801 microdiaphragms fabricated on the one wafer were $20.03\;{\mu}m$ and standard deviation was ${\pm}0.26{\mu}m$. The silicon surface of the etch-stopped microdiaphragm was extremely flat without noticeable taper or other nonuniformities. The benefits of the electrochemical etch-stop in a TMAH:IPA:pyrazine solution become apparent when reproducibility in the microdiaphragm thickness for mass production is considered. These results indicate that the electrochemical etch-stop in a TMAH:IPA:pyrazine solution provides a powerful and versatile alternative process for fabricating high-yield silicon microdiaphragms.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.3
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• pp.223-227
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• 2001

In this paper, the authors present the fabrication of high-yield Si thin-membranes by electrochemical etch-stop in tetramethyl ammonium hydroxide (TMAH): isopropyl alcohol (IPA):pyrazine solutions. The current-voltage (I-V) characteristics of n- and p-type Si in TMAH:IPA;pyrazine solutions were analysed, repsectively. Open circuit potential (OCP)and passivation potential (PP) of n- and p-type Si, respectively, were obtained and applied potential was selected between n- and p-type Si PPs. The electrochemical etch-stop method was applied to the fabrication of 801 micro-membranes with 20.0 $\mu\textrm{m}$ thickness on a 5" Si wafer. The average thickness of fabricated 801 micro-membranes on one wafer 20.03$\mu\textrm{m}$ and the standard deviation was ${\pm}$0.26$\mu\textrm{m}$. The Si surface of the etch-stopped micro-membranes was extremely flat with no noticeable taper or nonuniformity. The results indicate that use of the electrochemical etch-stop method for the etching of Si in TMAH:IPA;pyrazine solutions provides a powerful and versatile alternative process for fabricating high-yield Si micro-membranes.

• Transactions on Electrical and Electronic Materials
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• v.2 no.2
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• pp.26-31
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• 2001

This paper presents the electrochemical etch-stop characteristics of single-crystal Si(001) wafers in tetramethyl ammonium hydroxide(TMAH):isopropyl alcohol(IPA):pyrazine solutions. The addition of pyrazine to TMAH:IPA solutions increased the etch rate of (100) Si, thus the etching time required by the etch-stop process shortened. The current-voltage(I-V) characteristics of n- and p-type Si in TMAH:IPA:pyrazine solutions were obtained, respectively. Open circuit potential(OCP) and passivation potential(PP) of n- and p-type Si, respectively, were obtained and applied potential was selected between n- and p-type Si PPs. The electrochemical etch-stop method was used to fabricate 801 microdiaphragms of 20 ${\mu}{\textrm}{m}$ thickness on a 5-inch Si wafer. The average thickness of fabricated 801 microdiaphragms on one Si wafer was 20.03 ${\mu}{\textrm}{m}$ and the standard deviation was $\pm$0.26 ${\mu}{\textrm}{m}$. The Si surface of the etch-stopped microdiaphragm was extremely flat with no noticeable taper or nonuniformity.

• Journal of the Korean Geotechnical Society
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• v.17 no.4
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• pp.289-299
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• 2001

본 연구는 균질 및 2개층 비균질지반에서 사질토지반 상에 놓인 정방형 기초의 극한지지력과 침하에 대하여 고찰하였다. 본 연구는 얕은기초의 거동에 대한 정방형 기초의 크기, 지반 상대밀도, 기초 폭에 대한 상부층의 두께 비(H/B), 상부층 아래 경계면의 경사($\theta$) 그리고 지반강성비의 영향을 규명하기 위하여 모형실험을 수행하였다. 동일 상대밀도에서 지지력 계수($N_{{\gamma}}$)는 일정하지 않으며 기초 폭에 직접적으로 관련되며 지지력계수는 기초 폭이 증가함에 따라 감소하였다. 기초크기의 영향과 구속압력의 영향을 고려하는 Ueno 방법에 의한 극한지지력의 예측값은 고전적인 지지력 산정식보다 더 잘 일치하며 그 값은 실험값의 65% 이상으로 나타났다. $\theta$=$0^{\circ}$인 2개층 지반의 결과에 근거하여, 극한지지력에 대한 하부층 지반의 영향을 무시할 수 있는 한계 상부층 두께는 기초 폭의 2배로 결정되었다. 그러나, 73%의 상부층 상대밀도인 경우는 침하비($\delta$B) 0.05 이하에서만 이 결과가 유효하였다. 경계면이 경사진 2개층 지반의 결과에 근거하여, 상부층의 상대밀도가 느슨할수록 그리고 상부층의 두께가 클수록 극한지지력에 대한 경계면 경사의 영향은 크지 않는 것으로 나타났다. 경계면의 경사가 증가함에 따른 극한침하량의 변화는 경계면이 수평인 경우($\theta$=$0^{\circ}$)를 기준으로 0.82~1.2(상부층 $D_{r}$=73%인 경우) 그리고 0.9~1.07(상부층 $D_{r}$=50%인 경우) 정도로 나타났다.Markup Language 문서로부터 무선 마크업 언어 문서로 자동 변환된 텍스트를 인코딩하는 경우와 같이 특정한 응용 분야에서는 일반 문자열에 대한 확장 인코딩 기법을 적용할 필요가 있을 수 있다.mical etch-stop method for the etching of Si in TMAH:IPA;pyrazine solutions provides a powerful and versatile alternative process for fabricating high-yield Si micro-membranes. the RSC circle, but also to the logistics system in the SLC circle. Thus, the RSLC model can maximize combat synergy effects by integrating the RSC and the SLC. With a similar logic, this paper develops "A Revised System of Systems with Logistics (RSSL)" which combines "A New system of Systems" and logistics. These tow models proposed here help explain several issues such as logistics environment in future warfare, MOE(Measure of Effectiveness( on logistics performance, and COA(Course of Actions) for decreasing mass and increasing velocity. In particular, velocity in logistics is emphasized.