• Electrical & Electronic Materials
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• v.8 no.1
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• pp.90-94
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• 1995

Reactive Ion Etching(RIE) of Si$_{3}$N$_{4}$ in a CF$_{4}$/O$_{2}$ gas plasma exhibits such good anisotropic etching properties that it is widely employed in current VLSI technology. However, the RIE process can cause serious damage to the silicon surface under the Si$_{3}$N$_{4}$ layer. When an atmospheric pressure chemical vapor deposited(APCVD) SiO$_{2}$ layer is used as a etch-stop material for Si$_{3}$N$_{4}$, it seems inevitable to get a good etch selectivity of Si$_{3}$N$_{4}$ with respect to SiO$_{2}$. Therefore, we have undertaken thorough study of the dependence of the etch rate of Si$_{3}$N$_{4}$ plasmas on $O_{2}$ dilution, RF power, and chamber pressure. The etch selectivity of Si$_{3}$N$_{4}$ with respect to SiO$_{2}$ has been obtained its value of 2.13 at the RF power of 150 W and the pressure of 110 mTorr in CF$_{4}$ gas plasma diluted with 25% $O_{2}$ by flow rate.

• Korean Chemical Engineering Research
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• v.51 no.6
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• pp.755-759
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• 2013

The etch rate and etch profile of Si was investigated when Ar was added to an $SF_6$ plasma in the etch step of the Bosch process. A Si substrate was etched with the Bosch process using $SF_6$ and $SF_6$/Ar plasmas, respectively, in the etch step to analyze the effects of Ar addition on the etch characteristics of Si. When the Ar flow rate in the $SF_6$ plasma was increased, the etch rate of the Si substrate increased, had a maximum at 20% of the Ar flow rate, and then decreased. This was because the addition of Ar to the $SF_6$ plasma in the etch step of the Bosch process resulted in the bombardment of Ar ions on the Si substrate. This enhanced the chemical reactions (thus etch rates) between F radicals and Si as well as led to sputtering of Si particles. Consequently, the etch rate was higher more than 10% and the etch profile was more anisotropic when the Si substrate was etched with the Bosch process using a $SF_6$/Ar (20% of Ar flow rate) plasma during the etch step. This work revealed a feasibility to improve the etch rate and anisotropic etch profile of Si performed with the Bosch process.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.1
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• pp.31-38
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• 2002

In order to improve the 0.35 $mutextrm{m}$-via hole etching process the etching characteristic of the gas $C_2F_{6}$ has been analyzed. The samples were triple-layer films(TEOS/SOG/TEOS) on 8-inch wafers and the orthogonal array matrix technique was used for the process. The equipment for etching was the transformer coupled plasma (TCP) source which is a type of high density plasma(HDP). This experiment showed the etching rate for $C_2F_{6}$ was 0.8 $mutextrm{m}$/min-1.1 $mutextrm{m}$/min and the measured uniformity was under $pm$6.9% in the matrix window. The CD skew comparison between pre and post-etching was under 10% which is an outstanding results in the window of profile in anisotropic etching. There was no problem in C2F6 with the flow rate of 20sccm, but when 14sccm of $C_2F_{6}$ was supplied there was a recess problem on the inner wall of SOG film. Consequently the etching characteristic of $C_2F_{6}$ shows a fast etching rate and a very wide process window in HDP TCP.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.373-375
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• 2011

최근 태양전지 연구에서 저가격화를 실현하는 방법 중 하나로 폐 실리콘 웨이퍼를 재생하는 방법에 관하여 많은 연구가 진행되고 있다. 그러나 기존 웨이퍼 재생공정은 높은 재처리 비용과 복잡한 공정등의 많은 단점을 가지고 있다. 결정형 태양전지에서 저가격화 및 고효율은 태양전지를 제작하는데 있어 필수 요소 이다. 그 중 결정질 태양전지 고효율을 위한 여러 연구 방법 중 표면 텍스쳐링(texturing)에 관한 연구가 활발하다. 텍스쳐링은 표면반사에 의한 광 손실을 최소화 하여 효율을 증가시키기 위한 방법으로 습식 식각과 건식 식각을 사용하여 태양전지 표면 위에 요철 및 피라미드구조를 형성하여 반사율을 최소화 시킨다. 건식식각은 습식식각과 다른 환경적 오염이 적은 것과 소량의 가스만으로 표면 텍스쳐링이 가능하여 많은 연구가 진행중이다. 건식 식각 중 하나인 RIE(reactive ion etching)는 고주파를 이용하여 플라즈마의 이온과 silicon을 반응 시킨다. 실험은 RIE를 이용하여 SF6/02가스를 혼합하여 비등방성 에칭 및 피라미드 구조를 구현하였다. RIE 공정 중 SF6/02가스는 높은 식각 율을 갖으며 self-masking mechanism을 통해 표면이 검게 변화되고 반사율이 감소하게 된다. 이 과정을 통해 블랙 실리콘을 형성하게 된다. 블랙 실리콘은 반사율 10% 이하로 self-masking mechanism으로 바늘모양의 구조를 형성되는 게 특징이며 표면이 검은색으로 반사율이 낮아 효율증가로 예상되지만 실제 바늘 모양의 블랙 실리콘은 태양전지 제작에 있어 후속 공정 인 전극 형성 시 Ag Paste의 사이즈와 표면 구조를 감안할 때 태양 전지 제작 시 Series resistance를 증가로 효율 저하를 가져온다. 본 연구는 SF6/02가스를 혼합하여 기존 RIE로 형성된 바늘모양의 구조의 블랙 실리콘이 아닌 RIE 내부에 metal-mesh를 장착하여 단결정(100)실리콘 웨이퍼 표면을 텍스쳐링 하였고 SF6/02 가스 1:1 비율로 공정을 진행 하였다. metal-mesh 홀의 크기는 100um로 RIE 내부에 장착하여 공정 시간 및 Pressure를 변경하여 실험을 진행하였다. 공정 시간이 변경됨에 따라 단결정(100) 실리콘 웨이퍼 표면에 피라미드 구조의 균일한 1um 크기의 블랙 실리콘을 구현하였다. 바늘모양의 블랙 실리콘을 피라미드 구조로 구현함으로써 바늘 모양의 단점을 보완하여 태양전지 전기적 특성을 분석하여 태양전지 제작시 변환 효율을 증가시킬 것으로 예상된다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1522-1526
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• 2005

In this study, the fabrication of large area silicon mirror is accomplished by anisotropic etching using MEMS for implementation of integrated optical pickup and the process condition is also established for improving the mirror surface roughness. Until now, few results have been reported about the production of highly stepped $9.74^{\circ}$ off-axis-cut silicon wafer using wet etching. In addition rough surface of the mirror is achieved in case of long etching time. Hence a novel method called magnetorheolocal finishing is introduced to enhancing the surface quality of the mirror plane. Finally, areal peak to valley surface roughness of mirror plane is reduced about 100nm in large area of $mm^2$ and it is applicable to optical pickup using infrared wavelength.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.1 s.178
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• pp.89-96
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• 2006

In this study, fabrication of the large area silicon mirror is accomplished by anisotropic wet etching using micromachining technology for implementation of integrated slim optical pickup and the process condition is also established for improving the mirror surface roughness. Until now, few results have been reported about the production of highly stepped $9.74^{\circ}$ off-axis-cut silicon wafers using wet etching. In addition rough surface of the mirror is achieved in case of tong etching time. Hence a novel method called magnetorheolocal finishing is applied to enhance the surface quality of the mirror plane. Finally, areal peak to valley surface roughness of mirror plane is reduced about 100nm in large area of $mm^2$ and it is applicable to optical pickup using infrared wavelength.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1708-1709
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• 2011

본 논문에서는 Ambipolar 실리콘 나노와이어 FET (SiNW FET)의 빛을 통한 모듈래이션을 분석하였다. Ambipolar SiNW FET를 얻기 위해서는 나노와이어가 저농도로 도핑된 실리콘이어야 한다. 실리콘의 비등방성 습식식각 이후, 산화 공정을 통한 나노와이어 제작을 통해 보론의 확산을 통해 저농도로 도핑된 실리콘 나노와이어를 제작하였다. 빛이 조사될 시에 생기는 Ambipolar SiNW FET의 모듈래이션 특성에 관해 분석하고 간단한 응용 실험을 통하여 검증하였다. 응용 실험 결과 pH 센싱의 감도는 빛을 10000 lux 조사할 경우 8.84 배 증가하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.1
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• pp.24-28
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• 2005

A micromachined biochip with a three dimensional silicon chamber was developed for the construction of biosensors. Anisotropic etching was used fur the formation of the chamber on the p-type silicon wafer(100) and then was glued to the Pyrex glass bottom-substrate with pre-deposited platinum electrode. The electrochemical characterization of its Pt electrode and Ag/AgCl reference electrode was investigated.

• Journal of the Korean Vacuum Society
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• v.7 no.4
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• pp.390-396
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• 1998

Neutral stream was generated from Helicon plasma source and was applied to etch silicon for the purpose of preventing physical and electrical damages from the bombardment of charged particles with high translation energy. By installing a permanent magnet and applying positive bias beneath the substrate, the cusp-magnetic and electric fiddles were generated in order to remove the charged particles from the downstream plasma. As a result, the electron density and ion density in the vicinity of the substrate were reduced by 1/1000 and 1/10, respectively. The directional etching of silicon was observed and the etch rate was found to be very low to below 100 $\AA$/min at a pressure of $8.5{\times}10^{-4}$ Torr, when $Cl_2$ and 10% $SF_{sigma}$ etchant gases were used.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.289-292
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• 2009

The fabrication method of glass bipolar plates for micro PEM fuel cell application has been established and performance evaluation has been carried out. The advantages of glass bipolar plates for micro PEM fuel cells are light weight, high chemical resistivity, and easy manufacture. The MEMS fabrication process of anisotropic wet etching, thermal & UV bonding along with metal layer deposition has been introduced. From performance evaluation, it was shown that the micro fuel cell with a metal layer deposited on the reactive area yielded higher power density than the one without it. But both power densities of the two cases showed out to be adequate with the current status of micro fuel cell technology.