• Journal of the Microelectronics and Packaging Society
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• v.7 no.3
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• pp.13-17
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• 2000

The electrical properties of polyimide for interlayer dielectric applications are investigated with ECR (Electron Cyclotron Resonance) etching process. ECR etching with $Cl_2$-based plasma, generally used for aluminum etching, results in an increase in the dielectric constant of polyimide, while $SF_{6}$ plasma exhibits a high polyimide etch rate and a reducing effect of the dielectric constant. The leakage current of the polyimide is significantly suppressed after plasma exposure. Combination of Al etching with $Cl_2$plasma and polyimide etching with $SF_{6}$ plasma is expected as a good tool for realizing the multilevel metallization structures.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.29-32
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• 1999

$GaF_3$ films were directly grown on p' and p-type GaAs(100) substrates using a $SF_6$ plasma discharge system. GaAs MIS(Meta1-Insulator-Semiconductor) capacitor was successfully fabricated for about 1 hour at temperature $290^{\circ}C$ using the as-grown $GaF_3$ films. The as-grown films on p'-GaAs exhibited a current density of less than 6.68 $\times$ $1O^{-9}$ A/$cm^2$ at a breakdown field of 500kV/cm and a refractive index of 2.0 ~ 2.3 at a wavelength of 632.8 nm. The dielectric constant was about 5 derived from 1 MHz capacitance-voltage (C-V) measurements. Dielectric dispersion of the fluoridated films on p'-GaAs measured ranged from 100 Hz to 10 MHz was not observed.

• Journal of the Microelectronics and Packaging Society
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• v.8 no.3
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• pp.63-67
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• 2001

Up to now, most studies about Pt-etching have been focused on physical sputtering mechanism with Cl-based plasma, while only a limited results are available for etching characteristics with fluorine-based plasma. In this study, etch characteristics of Pt thin film with $Cl_2$/Ar and $SF_{6}$/Ar Ar gas chemistries have been studied with ECR plasma etching system. It is confirmed that $SF_{6}$/Ar Ar plasma chemistry could make volatile etch-products through the reaction with Pt thin film. Also the improvement in etch rate, etch profile and surface roughness is obtained due to the formation of volatile platinum fluoride compounds.

• Journal of the Korean Vacuum Society
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• v.17 no.1
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• pp.16-22
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• 2008

We studied plasma etching of polycarbonate in $O_2/SF_6$, $O_2/N_2$ and $O_2/CH_4$. A capacitively coupled plasma system was employed for the research. For patterning, we used a photolithography method with UV exposure after coating a photoresist on the polycarbonate. Main variables in the experiment were the mixing ratio of $O_2$ and other gases, and RF chuck power. Especially, we used only a mechanical pump for in order to operate the system. The chamber pressure was fixed at 100 mTorr. All of surface profilometry, atomic force microscopy and scanning electron microscopy were used for characterization of the etched polycarbonate samples. According to the results, $O_2/SF_6$ plasmas gave the higher etch rate of the polycarbonate than pure $O_2$ and $SF_6$ plasmas. For example, with maintaining 100W RF chuck power and 100 mTorr chamber pressure, 20 sccm $O_2$ plasma provided about $0.4{\mu}m$/min of polycarbonate etch rate and 20 sccm $SF_6$ produced only $0.2{\mu}m$/min. However, the mixed plasma of 60 % $O_2$ and 40 % $SF_6$ gas flow rate generated about $0.56{\mu}m$ with even low -DC bias induced compared to that of $O_2$. More addition of $SF_6$ to the mixture reduced etch of polycarbonate. The surface roughness of etched polycarbonate was roughed about 3 times worse measured by atomic force microscopy. However examination with scanning electron microscopy indicated that the surface was comparable to that of photoresist. Increase of RF chuck power raised -DC bias on the chuck and etch rate of polycarbonate almost linearly. The etch selectivity of polycarbonate to photoresist was about 1:1. The meaning of these results was that the simple capacitively coupled plasma system can be used to make a microstructure on polymer with $O_2/SF_6$ plasmas. This result can be applied to plasma processing of other polymers.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.6
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• pp.447-452
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• 1998

The selective dry etching of GaAs to Al\ulcornerGa\ulcornerAs using $BCI_3/SF_6$ gas mixture in electron cyclotron resonance(ECR) plasma is investigated. A selectivity of GaAs to AlGaAs of more than 100 and maximum etch rate of GaAs are obtained at a gas ratio $SF_6/BCI_3+SF_6$ of 25%. We verified the formation of $AlF_3$ on $Al_{0.25}Ga_{0.75}As$from the Auger spectra which enhanced the etch selectivity. In order to investigate surface damage of AlGaAs caused by ECR plasma, we performed a low temperature photoluminescence(PL) measurement as a function of RF power. As the RF power. As the RF power increases, the PL intensity decreases monotonically from 50 to 100 Wand then repidly decreases until 250 W. This behavior is due to surface damage by plasma treatment. This dry etching technique using $BCI_3/SF_6$ gas mixture in ECR plasma is suitable for gate recess formation on the GaAs based pseudomorphic high electron mobility transistor(PHEMT)

• Proceedings of the Materials Research Society of Korea Conference
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• 2001.11a
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• pp.60-60
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• 2001

• Clean Technology
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• v.19 no.2
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• pp.113-120
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• 2013

The treatment of chemically stable perflourocompounds (PFCs) requires a large amount of energy. An energy efficient arc plasma system has been developed to overcome such disadvantage. $CF_4$, $SF_6$ and $NF_3$ were injected into the plasma torch directly, and net plasma power was estimated from the measurement of thermal efficiency of the system. Effects of net plasma power, waste gas flow rate and additive gases on the destruction and removal efficiency (DRE) of PFCs were examined. The calculation of thermodynamic equilibrium composition was also conducted to compare with experimental results. The average thermal efficiency was ranged from 60 to 66% with increasing waste gas flow rate, while DRE of PFCs was decreased with increasing gas flow rate. On the other hand, DRE of each PFCs was increased with the increasing input power. Maximum DREs of $CF_4$, $SF_6$ and $NF_3$ were 4%, 15% and 90%, respectively, without reaction gas at the fixed input power and waste gas flow rate of 3 kW and 70 L/min. A rapid increase of DRE was found using hydrogen or oxygen additional gases. Hydrogen was more effective than oxygen to decompose PFCs and to control by-products. The major by-product in the arc plasma process with hydrogen was hydrofluoric acid that is easy to be removed by a wet scrubber. DREs of $CF_4$, $SF_6$ and $NF_3$ were 25%, 39% and 99%, respectively, using hydrogen additional gas at the waste gas flow rate of 100 L/min and the input power of 3 kW.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.67-67
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• 2011

Pulsed DC $BCl_3/SF_6$ 플라즈마를 사용하여 GaAs와 AlGaAs의 건식 식각을 연구하였다. 식각 공정 변수는 가스 유량 (50~100 % $BCl_3$ in $BCl_3/SF_6$), 펄스 파워 (450~600 V), 펄스 주파수 (100~250 KHz), 리버스 시간 (0.4~1.2 ${\mu}s$)이었다. 식각 공정 후 표면 단차 측정기 (Surface profiler)를 사용하여 표면의 단차와 거칠기를 분석하였다. 그 결과를 이용하여 식각률 (Etch rate), 표면거칠기 (Surface roughness), 식각 선택비 (Selectivity)와 같은 특성 평가를 하였다. 실험 후 주사 현미경 (FE-SEM, Field Emission Scanning Electron Microscopy)을 이용, 식각 후 시료의 단면과 표면을 관찰하였다. 실험 결과에 의하면 1) 18 sccm $BCl_3$ / 2 sccm $SF_6$, 500 V (Pulsed DC voltage), 0.7 ${\mu}s$ (Reverse time), 200 KHz (Pulsed DC frequency), 공정 압력이 100 mTorr인 조건에서 GaAs와 Al0.2Ga0.8As의 식각 선택비가 약 48:1로 우수한 결과를 나타내었다. 2) 펄스 파워 (Pulsed DC voltage), 리버스 시간(Reverse time), 펄스 주파수(Pulsed DC frequency)의 증가에 따라 각각 500~550 V, 0.7~1.0 ${\mu}s$, 그리고 200~250 KHz 구간에서 AlGaAs에 대한 GaAs의 선택비가 감소하게 되는 것을 알 수 있었다. 이는 척 (chuck)에 인가되는 전류와 파워를 증가시키고, 따라서 GaAs의 식각률이 크게 증가했지만 AlGaAs 또한 식각률이 증가하게 되면서 GaAs에 대한 식각 선택비가 감소한 것으로 생각된다. 3) 표면 단차 측정기와 주사전자현미경 사진 결과에서는 GaAs의 경우 10% $SF_6$ (18 sccm $BCl_3$ / 2 sccm $SF_6$)가 혼합된 조건에서 상당히 매끈한 표면 (RMS roughness < 1.0 nm)과 높은 식각률 (~0.35 ${\mu}m$/min), 수직의 식각 측벽 확보에서 매우 좋은 결과를 보여주었다. 또한 같은 공정 조건에서 AlGaAs는 식각이 거의 되지 않은 결과 (~0.03 ${\mu}m$/min)를 보여주었다. 위의 결과들을 종합해 볼 때 Pulsed DC $BCl_3/SF_6$ 플라즈마는 GaAs와 AlGaAs의 선택적 식각 공정에서 매우 우수한 공정 결과를 나타내었다.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.365-368
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• 2002

The design of industrial arc plasma systems is still largely based on trial and error although the situation is rapidly improving because of the available computational power at a cost which is still fast coming down. The desire to predict the behavior of arc plasma system, thus reducing the development cost, has been the motivation of arc research. To interrupt fault current, the most enormous duty of a circuit breaker, is achieved by separating two contacts in a interruption medium, $SF_{6}$ gas or air etc., and arc plasma is inevitably established between the contacts. The arc must be controlled and interrupted at an appropriate current zero. In order to analyze arc behavior in $SF_{6}$ gas circuit breakers, a numerical calculation method combined with flow field and electromagnetic field has been developed. The method has been applied to model arc generated in the Aachen nozzle and compared the results with the experimental results. Next, we have simulated the unsteady flow characteristics to be induced by arcing of AC cycle, and conformed that the method can predict arc behavior in account of thermal transport to $SF_{6}$ gas around the arc, such as increase of arc voltage near current zero and dependency of arc radius on arc current to maintain constant arc current density.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.142-142
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• 2013

DBD (Dielectric Barrier Discharge) 대기압 플라즈마를 이용한 a-Si 식각기술에 대한 연구결과를 논하고자 한다. 기술개발의 목적은 대면적 TFT-LCD 혹은 Flexible Display 공정에 적용가능한 대기압 플라즈마 식각장치의 개발 및 검증이다. 실험에서 식각 가스로는 SF6, NF3 등을 사용하였으며, 질소를 기본 가스로 사용하였다. 검증용으로 개발된 대기압 플라즈마 식각 장치는 대기압 플라즈마 장치를 연속적으로 통과하는 in-line system 형식으로 개발되었다. 검증에 사용된 대기압 플라즈마 장치는 300 mm의 방전 폭으로 1세대 LCD기판의 처리가 가능하다. 대기압 플라즈마 식각 기술 개발에서 식각율에 영향을 미치는 변수들은 기판의 온도, 식각가스의 농도, 기판의 이송속도, 기판과 플라즈마 발생장치 사이의 간격 그리고 플라즈마의 인가 전력 등으로 크게 구분지어 생각할 수 있다. 개발된 식각 장치는 SF6를 사용하는 경우 최대 환산 식각율은 500 nm/min 정도이다. 식각 기술에서 중요한 식각 Uniformity와 그와 연관된 a-Si/SiNx 식각 선택비는 사용하는 가스의 Recipe 개발에 중점을 두고 연구를 진행하였다. 식각 Uniformity는 약 7% 이내의 균일도를 갖고 a-Si/ SiNx의 선택비는 10이상의 결과를 얻었다. 또한 식각 가스는 식각 profile에 영향을 줄 수 있는데 대기압 환경에서 형성되는 collisional sheath에도 불구하고 비 등방성 식각이 가능하였다.