• Korean Chemical Engineering Research
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• 제49권4호
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• pp.485-490
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• 2011

사불화탄소($CF_4$)는 반도체 제조공정에서 에칭과 반응기 세척에서 사용되어온 가스이다. $CF_4$는 적외선을 강하게 흡수하고 대기 중 잔류시간이 길어서 지구온난화에 영향을 미치기 때문에 고효율의 분해가 필요하다. 본 연구에서는 플라즈마와 워터젯을 결합하여 워터젯 글라이딩 아크 플라즈마 시스템을 개발하고, 이를 이용하여 $CF_4$를 고효율로 분해할 수 있도록 방전영역을 증가시키고 다량의 OH 라디칼을 생성시킬 수 있는 최적의 조업 조건을 결정하였다. 공정 실험 변수로는 워터젯 주입량, $CF_4$ 초기 농도, 전체 가스량과 주입에너지량(SEI : Specific energy input)을 선정하였다. 변수실험을 통하여 워터젯 주입량이 25.5 mL/min, $CF_4$ 초기 농도 2.2%, 전체 가스량 9.2 L/min, SEI 7.2 kJ/L일 때 $CF_4$ 분해율은 최고 97%까지 도달하였다.

• 한국연소학회지
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• 제22권4호
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• pp.51-56
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• 2017

The decomposition of tetrafluoromethane has been investigated with the reaction mechanism proposed for freely propagating $CH_4/CF_4/O_2/N_2$ premixed flames on the oxygen enrichment. The factors affecting on the removal efficiency of tetrafluoromethane were analyzed. The increase in flame temperature due to oxygen enrichment has a great influence on the removal efficiency of tetrafluoromethane. At the same oxygen enrichment condition, the removal efficiency in the rich flame is higher than one in the lean flame. The increase of the F/H ratio leads to decrease the flame temperature and the removal efficiency of tetrafluoromethan is decreased at the flame temperature of 2600 K or lower, The elementary reactions that dominate the consumption of tetrafluoromethane are (R1) $CF_4+M=CF_3+F+M$ and (R2) $CF_4+H=CF_3+HF$. (R1) has the greatest effect on the consumption of tetrafluoromethane under the oxygen enhanced flames.

• 멤브레인
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• 제22권3호
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• pp.201-207
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• 2012

본 연구에서는 PDMS (poly-dimethylsiloxane)와 PEBAX (polyether block amides) 분리막을 이용해 $N_2$, $O_2$, $CF_4$와 $SF_6$의 단일 기체 투과특성에 관하여 연구하였다. 다양한 압력으로 공급된 기체의 투과유량을 진공가압 연속흐름방식으로 측정하였으며, 이를 이용하여 투과도를 산정하였다. PDMS 분리막에서는 상부의 압력이 증가할수록 $SF_6$를 제외한 다른 기체의 투과도는 감소하였다. 또한 $SF_6$의 투과도가 $CF_4$보다 높게 나타나고 있으며 이것은 $SF_6$가 더 높은 임계온도를 가지고 있기 때문이다. PDMS 분리막에서 투과도는 $O_2$ > $N_2$ > $SF_6$ > $CF_4$ 순으로 감소하였다. 반면에 PEBAX 분리막에서 기체의 투과 경향은 $O_2$ > $N_2$ > $CF_4$ > $SF_6$ 순으로 감소하였다. 이러한 경향은 각 기체의 운동 반경의 크기(${\AA}$)($SF_6$ > $CF_4$ > $N_2$ > $O_2$) 순서와 반대로 나타났다. $SF_6/CF_4$의 순수 기체의 선택도는 PDMS 분리막에서 0.7 MPa일 때 2.1로 나타났다.

• 전기학회논문지
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• 제57권2호
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• pp.245-251
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• 2008

Although many studies have been carried out about binary gas mixtures with $SF_6$, few studies were presented about breakdown characteristics of $SF_6/CF_4$ mixtures. At present study the breakdown characteristics of $SF_6/CF_4$ mixtures in non-uniform field was performed. The experiments were carried out under AC voltage and standard lightning impulse(SLI) voltage. Breakdown characteristics were investigated for $SF_6/CF_4$ mixtures when AC voltages and standard lighting impulse voltage was applied in a needle-plane. The needle-plane electrode whose gap distance was 3 mm were used in a test chamber. $SF_6/CF_4$ mixtures contained from 0 to 100% $SF_6$ and the experimental gas pressure ranged from 0.1 to 0.5 MPa. The breakdown characteristics of $SF_6/CF_4$ mixtures in non-uniform field may be influenced by defects like needle-shaped protrusions. In case of slowly rising SLI voltage and AC voltage it is enhanced by corona-stabilization. This phenomena caused by the ion drift during streamer development and the resulting space-charge is investigated. In non-uniform field under negative SLI voltage the breakdown voltage was increase linearly but under positive SLI voltage the breakdown voltage increase non-linearly. The breakdown voltage in needle-plane electrode displayed N shape characteristics for increasing the content of $SF_6$ at AC voltage. $SF_6/CF_4$ mixture has good dielectric strength and arc-extinguishing properties than pure SF6. This paper presents experimental results on breakdown characteristics for various mixtures of $SF_6/CF_4$ at practical pressures. We could make an environment friendly gas insulation material with maintaining dielectric strength by combing $SF_6\;and\;CF_4$ which generates a lower lever of the global warming effect.

• 한국전기전자재료학회논문지
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• 제14권12호
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• pp.959-964
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• 2001

We investigated the etching characteristics of YMnO$_3$ thin films in high-density plasma etching system. In this study, YMnO$_3$ thin films were etched with CF$_4$/Ar gas chemistries in inductively coupled plasma(ICP). Etch rates of YMnO$_3$ increased up to 20% CF$_4$ in CF$_4$/(CF$_4$+Ar), but decreased with furthermore increasing CF$_4$ in CF$_4$/(CF$_4$+Ar). In optical emission spectroscopy (OES) analysis, F radical and Ar* ions in plasma at various gas chemistries decreased with increasing CF$_4$ content. Chemical states of YMnO$_3$ films exposed in plasma were investigated with x-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). There is a chemical reaction between metal (Y, Mn) and F and metal-fluorides were removed effectively by Ar ion sputtering. YF$_{x}$, MnF$_{x}$ such as YF, YF$_2$, YF$_3$ and MnF$_3$ were detected using SIMS analysis. The etch slope is about 65$^{\circ}$ and cleasn surface. surface of the etched YMnO$_3$ thin films was investigated with X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). The etch profile was also investigated by scanning electron microscopy (SEM).EM).

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.62-65
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• 2001

$SrBi_2Ta_2O_{9}$ thin films were etched in inductively coupled $Cl_{2}$/$CF_{4}$/Ar plasma. The maximum etch rate was 1060 $\AA\textrm{m}$/min in $Cl_{2}$/$CF_{4}$/Ar (80). The chemical reactions on the etched surface were studied with x-ray photoelectron spectroscopy. The etching of SBT thin films in $Cl_{2}$/$CF_{4}$/Ar were etched by chemically assisted reactive ion etching. The small addition of $Cl_2$ into $CF_4$(20)/Ar(80) plasma will decrease the fluorine radicals and the increase Cl radical.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1820-1822
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• 2002

본 논문에서는 반도체 제조공정에서 발생하는 $CF_4$의 분해와 제거를 위하여 3상 교류 플라즈마 토치를 제작하고, 플라즈마를 발생시켜 $CF_4$제거 가능성과 이에 따른 문제점에 대해 알아보았다. 매우 강하고 안정한 C-F 결합을 깨고 $CF_4$가스를 분해하기 위해서는 1100[$^{\circ}C$]정도의 고온이 필요한데, 본 실험의 플라즈마 플레임의 경우 $CF_4$가스를 열분해 광분해 시키기에는 충분한 온도와 에너지를 가지고 있다고 사료된다. 하지만 고온의 플라즈마와 토치 내부의 복잡한 유동과 고온의 플라즈마에 의한 전극의 융삭문제는 플라즈마를 연속적으로 발생시켜 $CF_4$가스의 제거효율을 높이기 위해서는 필히 개선해야 할 문제점인 것으로 사료된다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 제4회 영호남학술대회 논문집
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• pp.133-137
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• 2002

In this paper, the $CF_{4}$ decomposition rate are investigated for a simulated three plasma reactors which are metal particle reactor, spiral wire reactor and reactor with porous dielectric as applied voltage. The $CF_{4}$ decomposition rate by plasma reactor with porous dielectric had a gain of 20~25[%] over that by plasma reactor with spiral wire or metal particle electrode. The $CF_{4}$ decomposition efficiency increases with increasing applied voltage up to the critical voltage for spark formation. The $CF_{4}$ decomposition efficiency of metal particle reactor was about 80[%] at AC 24[kV]. However, decomposition efficiency is more than 90% in case of the reactor with porous dielectric. we think, the reactor with porous dielectric should be much better than other reactors for $CF_{4}$ decomposition.

• Transactions on Electrical and Electronic Materials
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• 제4권4호
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• pp.30-35
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• 2003

In this paper, the $CF_4$ decomposition efficiency is investigated for three simulated plasma reactors that are needle plate reactor, metal particle reactor, and dielectric barrier reactor with hole (DBH). The$CF_4$ decomposition efficiency by DBH is much better than that by needle plate reactor or metal particle reactor. When applied voltage is increased up to the critical voltage for spark formation in the all reactors, the $CF_4$ decomposition efficiency is increased. The $CF_4$ decomposition efficiency in needle plate reactor and metal particle reactor is about $12\%$ and $22\%$ respectively at applied voltage of 23 kV (consumption power: 110 W) and $CF_4$ concentration of 500 ppm, however, the $CF_4$ decomposition efficiency is more than $95\%$ in case of DBH. DBH should be much better than two reactors investigated for $CF_4$ decomposition.

• 전기학회논문지
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• 제57권4호
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• pp.635-640
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• 2008

New gas mixtures are now finding applications such as interrupting media for high-voltage circuit breakers. These mixtures consist of a high content of carbon tetrafluoride($CF_4$) added to sulfur hexafluoride($SF_6$). Nowdays $SF_6$ has been established for the use in gas insulated substations due to its high insulation withstand level and good arc quenching capability. At this paper Breakdown characteristics were investigated for $SF_6/CF_4$ mixtures when AC voltage and standard lightning impulse voltage(LI) was applied in a needle-plane electrodes. And partial discharge(PD) experiments were carried out in the test chamber which was made in needle-plane electrode. And ${\Phi}$-Q-N distribution of partial discharge signals was analyzed. The total pressure of the $SF_6/CF_4$ mixtures was varied within the range of 0.1-0.5 Mpa in the test chamber. The breakdown voltage in needle-plane electrode displayed N shape characteristics for increasing the content of $SF_6$ at positive impulse voltage and the PD inception voltage was increased slightly when pressure of $SF_6/CF_4$ Mixtures was increased. Maximum PD inception voltage is showed in 80% SF6/20%$CF_4$.