• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.79-80
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• 2007

Copper has been used as an interconnect material in the fabrication of semiconductor devices, because of its higher electrical conductivity and superior electro-migration resistance. Chemical mechanical polishing (CMP) technique is required to planarize the overburden Cu film in an interconnect process. Various problems such as dishing, erosion, and delamination are caused by the high pressure and chemical effects in the Cu CMP process. But these problems have to be solved for the fabrication of the next generation semiconductor devices. Therefore, new process which is electro-chemical mechanical planarization/polishing (ECMP) or electro-chemical mechanical planarization was introduced to solve the. technical difficulties and problems in CMP process. In the ECMP process, Cu ions are dissolved electrochemically by the applying an anodic potential energy on the Cu surface in an electrolyte. And then, Cu complex layer are mechanically removed by the mechanical effects between pad and abrasive. This paper focuses on the manufacturing of ECMP system and its process. ECMP equipment which has better performance and stability was manufactured for the planarization process.

• Korean Chemical Engineering Research
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• 제45권2호
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• pp.190-196
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• 2007

본 연구에서는 전기화학적 처리공정을 이용하여 전극판 종류에 따른 질산성 질소의 농도별 제거효율을 살펴보았고, 여기서 선정된 전극으로 운전조건(pH 변화, 전류밀도, 환원제, 교차전류)을 변화시켜 질산성 질소 제거효율, 에너지소모량에 따른 최적운전조건을 평가하였다. 또한 단일공정에 의한 처리가 아닌 다단계 전기화학적 처리를 통한 질산성 질소 제거 실험을 진행하였다. 100 mg $NO_3^{-}$ -N/L 농도로 실험한 결과에서 동일 전극인 경우 Zn-Zn 전극판, 불용성 산화전극 백금(Pt)인 경우 Pt-Ti 전극에서 높은 질산성 질소 제거효율을 나타내었다. 150 mg $NO_3^{-}$ -N/L에서 Zn-Zn 전극판인 경우 pH 조절없이 전기분해한 결과 70~85%, 불용성 산화전극인 백금(Pt)인 경우 Pt-Ti 전극에서 40~50%의 질산성 질소 제거효율을 나타내었다. 그리고 고농도인 500, 1,000 mg $NO_3^{-}$ -N/L 질산성 질소 제거 실험결과, 농도가 증가할수록 제거효율은 감소하는 경향을 보이지만 에너지 소모량에 대한 질소 제거효율은 증가하였다. 다단계 전기화학적 처리 실험결과, Test 4 조건을 최적의 조건으로 선정하였으며 그 이유는 다음과 같다. 첫 번째, 1단계에서 소모된 Zn 양극의 대부분을 2단계 이후 공정에서 회수하였고, 두 번째, 2단계 이후에서는 불용성 백금을 산화전극으로 사용함으로써 전극 소모 가능성을 줄였으며, 마지막으로 Zn을 환원전극으로 사용함으로써 Zn의 재이용 가능성을 높였다. 따라서, 질소를 함유한 표면처리 폐수 처리에 전기화학적 공정이 적용될 수 있을 것으로 판단된다.

• 한국전기전자재료학회논문지
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• 제18권9호
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• pp.793-797
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• 2005

This study introduces Electro-chemical Mechanical Deposition(ECMD) lot making Cu interconnect. ECMD is a novel technique that has ability to deposit planar conductive films on non-planar substrate surfaces. Technique involves electrochemical deposition(ECD) and mechanical sweeping of the substrate surface Preferential deposition into the cavities on the substrate surface nay be achieved through two difference mechanisms. The first mechanism is more chemical and essential. It involves enhancing deposition into the cavities where mechanical sweeping does not reach. The second mechanism involves reducing deposition onto surface that is swept. In this study, we demonstrate ECMD process and characteristic. We proceeded this experiment by changing of distribution of current density on divided water area zones and use different pad types.

• Design & Manufacturing
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• 제13권1호
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• pp.13-18
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• 2019

The size and prospects of the domestic semiconductor equipment market are increasing every year. In the case of various parts used inside semiconductor equipments, high durability such as high strength and abrasion resistance is demanded. Particularly, the gases used in semiconductor production processes are toxic. In order to prevent such toxic gas leakage, a precision processing technique and a surface treatment technique for preventing corrosion are required. Electro-polishing is an electro-chemical method of polishing a metal surface to make it smooth and polished. Electro-polishing is mainly used in the finishing process of metal surface. Unlike mechanical polishing, electro-polishing is used in many fields, such as fine chemical etching equipment, since no damaged layer or burr, fine polishing groove and particles are generated. However, in order to withstand the gas used in the semiconductor equipment, the parts must have high corrosion resistance. However, the surface hardness generally become lowered through electro-polishing. Therefore, in this study, surface hardness were experimentally observed before and after electro-polishing. Then, a method of improving hardness by preparing a nitrided layer by plasma ion nitriding treatment.

• 한국표면공학회지
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• 제40권5호
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• pp.203-208
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• 2007

Preliminary studies were conducted to develop a dimensionally stable anode (DSA)electrode prepared by reactive sputtering method. The microstructure, surface morphology and electrochemical properties of iridium oxide $(IrO_2)$ coatings synthesized by unbalanced magnetron sputtering (UBMS) and conventional DSA electrode were compared. In addition, the possibilities of $IrO_2$ films synthesized by UMB on a real DSA electrode were investigated by electro-chemical application test. The degree of non-stoichiometry and surface area were closely related to the electro-chemical activity of the $IrO_2$ electrode. The feasibility of making a DSA electrode prepared by PVD technique was demonstrated through the present work.

• 한국표면공학회지
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• 제51권5호
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• pp.325-331
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• 2018

Calcium carbonate($CaCO_3$) films were formed by an eco-friendly electro-chemical technique on steel substrates in synthesized distilled water solutions containing $NaHCO_3$, $CaCl_2$ and $MgCl_2$ with different ratio respectively. It was investigated to confirm the effect of $Mg^{2+}$ concentration by Scanning Electron Microscopy(SEM), Energy Dispersive x-ray Spectroscopy(EDS) and X-Ray Diffraction(XRD) respectively. From an experimental result, only calcite crystals were found in solution containing no $Mg^{2+}$. By increasing concentration of $Mg^{2+}$, deposition rate decreased and crystal structure was transformed form calcite to aragonite. In case of including $MgCl_2$ 300mM in synthesized solutions containing $NaHCO_3$, $CaCl_2$ 60mM, it was showed over the 90% of aragonite contents which have quite high deposition rate of aragonite. Also, it was confirmed that $Mg^{2+}$ acted as inhibitor on the films which made transforming from calcite to aragonite.

• 콘크리트학회논문집
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• 제11권6호
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• pp.79-88
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• 1999

In this paper, the electro-deposition method for the rehabilitation of cracked concrete, based on the electro-chemical technique, is presented. The main purpose of this paper is to apply this technique to reinforced concrete members on land. After cracking with a specified load(crack width 0.5mm), 10$\times$10$\times$20cm concrete specimens with embedded steel bars were immersed in several solutions, then a constant current density between the embedded steel in concrete and an electrode in the solution was applied for 4~20 weeks. The results indicate that electro-deposits formed in this process are able to close concrete cracks and to coat the concrete surface and that formation of these electro-deposits is confirmed to have an effect of protection against detrimental materials. Therefore, it is demonstrated that the electro-deposition method can be usefully applied for the rehabilitation technique of concrete.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.42-45
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• 2004

Electrochemical discharge machining (ECDM) has been found to be suitable for the micro-hole machining of nonconductive materials such as ceramics or glass compared with existing conventional and also non-conventional machining methods. However this machining process has some problems such as low geometric accuracy and low machining efficiency due to the random spark generation at the end of the electrode. This paper proposes the methods to improve the geometric accuracy of micro-hole using powder mixed ECDM process. The experimental results show the effects of powder producing improved geometric accuracy of machined hole and decreased concentration of spark energy.

• Korean Chemical Engineering Research
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• 제47권1호
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• pp.72-78
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• 2009

전기전도성 이방성 복합재료의 방전가공에 대하여 비정상상태 수식모델을 세우고 갤러킨의 유한요소법으로 해를 구하였다. 피삭재의 온도 분포와 분화구의 모양 및 공작물 제거 속도를 공정 매개변수에 관하여 구득하였다. 계산의 정확도와 효율을 위하여 앞선 연구에서 최적치로 선정된 $12{\times}12$ 요소의 비규칙 체눈을 사용하였다. 알루미나/티타늄 카바이드 복합재료의 물성을 재료의 물성으로 선정하였고 51.4 V의 전압과 7 A의 전류를 갖는 전력을 적용하였으며 제거 효율을 10%로 전열 이방성 계수를 2와 3으로 가정하였다. 불꽃이 일어나면서 피삭재는 즉시 녹기 시작하였고 열적 손상 영역이 형성되었다. 또한 시간이 흘러감에 따라서 분화구의 경계가 이동하는 것이 확인되었다. 반경 방향과 축 방향의 열전도도가 독립적으로 커지면 온도분포와 분화구의 모양이 각각 반경 방향과 축 방향으로 이동하였다. 공작물 제거 속도는 축 방향의 열전도도보다 반경 방향의 열전도도가 증가할 때 더욱 커지는 것으로 나타났다.

• Korean Chemical Engineering Research
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• 제57권2호
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• pp.259-266
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• 2019

Tuning of electro-optical properties of nano-structured $SnO_2:Ga$ powders in a micro drop fluidized reactor (MDFR) was highly effective to enhance the activities of powders to be used as sensor materials. The tuning was conducted continuously in a facile one-step process during the formation of powders. The microscopic hydrodynamic forces affected the band gap structure and charge transfer of $SnO_2:Ga$ powders through the oxygen and interfacial tin vacancies by providing plausible pyro-hydraulic conditions, which resulted in the decrease in the electrical resistance of the materials. The analyses of room-temperature photoluminescence (PL) spectra and FT-IR exhibited that the tuning could improve the surface activities of $SnO_2:Ga$ powders by adjusting the excitation as well as separation of electrons and holes, thus maximizing the oxygen vacancies at the surface of the powders. The scheme of photocatalytic mechanism of $SnO_2:Ga$ powders was also discussed.