실리콘 웨이퍼 공정용 알루미나 정전척의 제작과 특성에 관한 연구

천희곤,조동율,이영섭,박용균,최성호,정광진,Serguei Spoutai 울산대학교 기계부품 및 소재 특성평가연구센터 1999 연구보고서 Vol.1999 No.-

정전척의 유전체 물질로 열전도도와 유전특성 그리고 기계적 특성이 우수한 알루미나에 TiO₂첨가하여 유전체의 비저항을 변화시켜서 정전척(electrostatic chuck)에서 발생하는 정전력인 쿨롱힘(coulomb force)과 존슨-라벡힘(Johnsen-Fahbeck firce_의 영향을 규명하려 하였다. 그리고 비저항, 인가전압, 온도, 습도가 정전력에 어떠한 영향을 주는지 고찰하였으며, 인가전압에 따른 응답 특성에 관하여 고찰하였다. Alumina electrostatic chucks for silicon wafer process with wide range of electrical resistivity were fabricated by controlling the amount of TiO₂ addition (0 wt%, 1.3 wt%, 2 wt%, 2.8 wt%). The dependence of electrostatic force on applied voltage, temperature and humidity was investigated. In addition, response characteristics on applied voltage and relationship between electrical resistivity and electrostatic force characteristics such as Coulomb force and Johnsen-Rahbeck force were discussed

정전분무를 이용한 MOCVD에 의해 증착된 TiO_2 박막의 특성 연구

이영섭,박용균,이성재,조동율,천희곤 울산대학교 2002 공학연구논문집 Vol.33 No.1

정전분무(electrostatic spray)를 이용한 MOCVD방법은 원료를 함유하는 용액을 이용함으로써 이송관의 가열이 필요 없이 장치를 간단하게 할 수 있고, 용액의 유량과 전기장의 세기에 따라 초미세 입자제어도 가능하며, 출발 용액으로부터 박막의 조성을 조절할 수 있는 등의 여러 가지 특징을 가지고 있다. 온도가 증가함에 따라 입자성장과 반응가스에 의한 표면의 밀도가 감소하여 표면조도가 증가하였다. 증착 시간이 증가함에 따라 막의 두께는 증가하지만, 증착시간이 지날수록 +전하를 띤 액적들은 이미 생성된 막의 영향으로 -가 인가된 기판으로의 전하이동을 방해받으므로 island성장과 모세관현상의 표면형상은 거칠고, porous해졌다. 인가전압이 증가할수록 분무시 액적의 사이즈가 작아지므로 막의 표면은 치밀해졌으며, 표면에는 완전분무하지 못한 모액적에 의해 생긴 입자의 수도 적은 경향을 보였다. 산소 분말이 증가할수록 Ti와 O의 세기는 증가하나, C의 세기는 감소하는 경향을 보였다. The electrostatic spray assisted MOCVD has the advantages of simple apparatus without the gas lines, easy control of nano-sized droplets by applied voltage and solution rates and easy control of compositions of thin films by controlling the composition of starting solution. At lower deposition temperatures the morphology of the layers are less porous and rough. With increasing deposition time and thus increasing layer thickness the morphologies of the layers are shift to porous top layer with dense bottom layer and then porous top layer with big sized grain of bottom layer as the result of low growth rates. XPS can be seen that Ti and O intensity increases but C intensity decreses with increasing O_2 flow rates.

대기압 플라즈마에 의한 냉간압연 스테인리스 Micro-Cleaning판재의 에 관한 연구

오상훈,이성기,윤재홍,조동율,박봉규,이성규 국립7개대학공동논문집간행위원회 2004 공업기술연구 Vol.4 No.-

Atmospheric Plasma Cleaning (APC) was studied for the residual rolling oil contaminants on the surface of cold rolled Stainless Steel after optimizing APC conditions. Electrodes were placed at a distance of 10mm, with an RF power of 220W, and line velocity of 0.5m/min. The residue left by APC was 0.78mg/m², which was less than that of the approximate 1mg/m² by other classical cleaning methods. Especially, APC combined with pre-cleaning by 550℃Nitrogen gas gave a residue of only 0.01mg/m². Cleaning effect are also improved when oxygen gas is added to the atmospheric plasma. It was confirmed by the investigation of the official Korea Chemical Analysis Center that the APC-hot nitrogen method is superior to other methods. The residual contaminants for different methods were as follow : the classical method : about 1mg/m², APC : 0.78mg/m², and APC-hot nitrogen : 0.10mg/m².

FC-25계 회주철의 이온질화처리에 따른 표면특성과 고온산화거동에 관한 연구

허인창,손근수,윤재홍,조동율,박봉규,김현수,김인수 대한금속재료학회 2005 대한금속·재료학회지 Vol.43 No.4

Surface properties and high temperature oxidation behavior were investigated for FC-25 Gray Cast Iron(GCI) and the ion nitrided GCI(N-GCI). The GCI was pre-cleaned to improve hardness to the optimum pre-sputtering parameters with an Ar/H₂ ratio of 1/2, working pressure of 3 torr, working temperature of 550℃ and working time of 1hour. The optimum nitriding conditions for the maximum hardness of 560575 Hv were an N₂/H₂ ratio of 3/1, working pressure of 3 torr, and working temperature of 575℃. The thickness of graphite in the GCI was increased by increasing the working temperature from 525℃ to 595℃ for the nitriding time of 6-18hrs. XRD patterns showed FeO and Fe₂O₃ peaks for both the oxidized N-GCI and GCI at temperatures of 600℃ and 800℃ under atmospheric environment for both 24 and 60hours. At 800℃, above the Fe4N decomposition temperature of 680℃, the oxidation rate of N-GCI was greater than that of the GCI. The most abundant nitride, Fe4N, was decomposed and the nitrogen gas given off by the decomposition made the protective film porous by degassing through the film. But at 600℃, below the decomposition temperature, the degree of oxidation of N-GCI was lower than that of the GCI because the nitride film worked as protective barrier for oxidation. (Received October 29, 2004)

FC-25계 회주철의 Boro-Nitriding 복합 표면처리에 따른 표면특성과 고온산화거동에 관한 연구

허인창,손근수,윤재홍,조동율,박봉규,김현수,김인수 대한금속재료학회 2005 대한금속·재료학회지 Vol.43 No.2

Surface properties and oxidation behavior were studied for FC-25 gray cast iron (GCI), ion nitrided CCI (N CCI), powder boronized CCI (B GCI) and powder boronized N CCI (B-N GCI). A boride (Fe2B and FeB) layer with a tooth shape was formed by boronizing GCI at 650℃. The thickness and hardness of the layer were proportional to boronizing temperature and time. The hardness was decreased as the depth of the boronized layer increased. The activation energy for boride formation was about 74 kJ/mol. The thickness of the graphite layer formed by boronizing was increased by increasing temperature and time. A silicon layer insoluble to borides accumulated beneath the boride layer. The major phases were Fe4N, Fe3N and FeN in the nitride layer formed by ion nitriding. The thickness and hardness of the layer increased with increasing nitriding temperature and time under the Fe4N decomposition temperature of 680℃. The hardness was maximum at the surface and decreased with increasing nitrided depth on B-N GCI at 700℃, above the Fe4N decomposition temperature. Hardness of B-N GCI at the layer depth of 10 μm was 1000 Hv, which was lower than that of the B GCI at the same condition. Also the layer thickness was 50 gm; 10 μm deeper than that of B GCI. The reason was that the nitrogen gas given off by the decomposition made the layer porous and facilitated the diffusion of oxygen and other reactants. The samples were oxidated at 800℃ for 48hrs under atmospheric air. Oxidation rate was in decreasing order of N GCI, GCI, B GCI and B-N GCI. Oxidation rates were greatly influenced by the diffusion of nitrogen gas formed by Fe4N decomposition over the decomposition temperature of 680℃ and the oxidation barrier of the less corrosive boride layer. (Received October 29, 2004)

UV/Cl₂(g)에 의한 Si-wafer 표면금속 오염물의 건식세정에 관한 연구

손동수,정광진,최성호,천희곤,조동율 울산대학교 1998 공학연구논문집 Vol.29 No.2

본 연구에서는 실리콘 웨이퍼 표면에 존재하는 미량의 Zn, Fe, Ti 금속 오염물들이 UV-excited chlorine radical을 이용한 건식세정 방법으로 제거되는 반응과정을 연구 하였다. 실리콘 웨이퍼 상에 진공증착법으로 원형패턴이 있는 Zn, Fe, Ti 박막을 증착시켜 상온 및 200℃에서 UV/CI₂세정하였을 때, 염소 래디컬(CI*)이 Fe, Zn, Ti와 반응하여 제거되는 것을 반응 전후 광학현미경과 SEM을 통해 표면 형상 변화를 관찰하였고, in-line으로 연결된 XPS를 통해서 반응 후 웨이퍼 표면에 남아있는 화합물의 화학적 결합상태를 관찰하였으며, UV/CI₂세정 후 실리콘 기판이 손상받는 정도를 알기 위해 AFM으로 표면 거칠기를 측정하였다. 광학현미경과 SEM의 분석에 의하면 Zn와 Fe는 쉽게 제거되는 반면 염화물을 형성하기 보다는 휘발성이 적은 산화물을 형성하는 경향이 강한 Ti은 약간만 제거되는 것을 확인하였다. XPS 분석을 통해서 이들 금속 오염물들이 chlorine radical과 반응하여 웨이퍼 표면에 금속 염화물을 형성하고 있는 것을 확인하였고, UV/CI₂세정처리를 하였을 때 실리콘 웨이퍼의 표면 거칠기가 약간 증가하는 것을 알 수 있었다. 지금까지의 결과를 통해 볼 때, 습식세정과 UV/CI₂건식세정을 병행하면 플라즈마 및 레이저를 사용하는 다른 건식세정 방법에 비하여 보다 저온에서 실리콘 기판의 큰 손상 없이 비교적 용이하게 금속 오염물을 제거할 수 있음을 알수 있었다. The reaction mechanisms of dry cleaning of Zn, Fe and Ti trace contaminants on the Si wafer using UV/CI₂ have been studied by SEM, AFM and XPS analyses. The patterned Zn, Fe and Ti films were deposited on the Si wafer surface by thermal evaporation and changes in the surface morphology after dry cleaning using CI₂and UV/CI₂at 200℃ were studied by optical microscopy and SEM. In addition changes in surface roughness of Si wafer by the cleaning was observed by AFM. The chemical bonding states of the Zn, Fe and Ti deposited silicon surface were observed with in-line XPS analysis. Zn and Fe were easily cleaned in the form of volatile zinc-chloride and iron-chloride as verified by the surface morphology changes. Ti which forms involatile oxides was not easily removed at room temperature but was slightly removed by UV/CI₂at elevated temperature of 200℃. It was also found that the surface roughness of the Si wafer increased after CI₂and UV/CI₂cleaning. Therefore, the metallic contaminants on the Si wafer can be easily removed at lower temperature by continuous processes of wet cleaning followed by UV/CI₂dry cleaning.

Thermal MOCVD와 DC pulsed PA-MOCVD에 의해 증착된 TiN 박막 연구

박용균,이영섭,이태수,이성재,조동율,천희곤 울산대학교 2001 공학연구논문집 Vol.32 No.1

유기화합물(TDEAT;Ti[N(C2H5)2]4)과 NH3를 이용하여 thermal MOCVD와 dc pulsed plasma assisted MOCVD(PA-MOCVD)인 2종류의 TiN박막을 증착하여 비교하였다. TiN박막의 특성분석은 XRD, AES, FE-SEM, α-step과 XPS로 연구하였다. DC pulsed plasma assisted MOCVD로 증착된 Tin박막은 ion bombardment 효과에 의해 열적으로 증착된 것보다 더 fine한 columnar구조를 나타내므로써 막의 결정질이 향상되었다. 플라즈마에서의 아르곤 이온의 충돌로 인해 탄소(C)는 오히려 유기 화합물보다 탄소 라디칼로 존재하였다. 따라서 탄소 라디갈은 기판의 강한 (-) potential에 의해 TiN박막에 trap되기 때문에 탄소(C)는 열적으로 증착된 TiN박막보다 더 많은 양이 존재하는 것으로 추정된다. By using of (TDEAT;Ti[N(C2H5)2]4)and ammonia gas source, we deposited two different TiN thin films with thermal MOCVD and dc pulsed plasma assisted MOCVD (PA-MOCVB). The properties of TiN thin films were studied by XRD, AES, FE - SEM, α - step and XPS analyses in this work. The TiN films deposited by dc pulsed PA - MOCVD have a little higher density and a fine columnar structure, compared with thermally deposited TiN thin films. This may be due to ion bombardment effect resulting in improved crystallinity in films. Carbon in the film may exist in the form of carbonic radical rather than organic compound because of collision with Ar ion in the plasma. Consequently, the content of carbon in the film of dc pulsed PA - MOCVD was higher than that in thermally deposited TiN films, because carbon radicals could be trapped in the film by strong negative potential of the substrate.

Laser Heat Treatment of HVOF WC-CrC-Ni Coating

Tong Yul Cho,Jae Hong Yoon,Yun Kon Joo,Wei Fang,Shi Hong Zhang,Hui Gon Chun,Sung Sik Ha,Soon Yong Hwang,Ming-Xi LI 한국표면공학회 2008 한국표면공학회 학술발표회 초록집 Vol.2008 No.-

The Lubricant Effect of Oxidation and Wear Products of HVOF Co-alloy T800 Powder Coating

( Tong Yul Cho ),( Jae Hong Yoon ),( Kil Su Kim ),( Ki Oh Song ),( Suk Jo Youn ),( Hui Gon Chun ),( Soon Young Hwang ) 한국부식방식학회(구 한국부식학회) 2007 Corrosion Science and Technology Vol.6 No.4

A Study on the Friction and Wear Properties of Tribaloy 800 Coating by HVOF Thermal Spraying

Tong Yul Cho,Jae Hong Yoon,Kil Su Kim,Suk Jo Youn,Ki Oh Song,Nam Ki Back,Hui Gon Chun,Soon Young Hwang 한국표면공학회 2006 한국표면공학회지 Vol.39 No.5

Tribaloy 800 (T800) powder is coated on the Inconel 718 substrate by the optimal High Velocity Oxy-Fuel (HVOF) thermal spray coating process developed by this laboratory. For the study of the possibility of replacing of the widely used classical chrome plating, friction, wear properties and sliding wear mechanism of coatings are investigated using reciprocating sliding tester both at room and at an elevated temperature of 1000°F (538°C). Both at room temperature and at 538°C, friction coefficients and wear debris of coatings are drastically reduced compared to those of non-coated surface of Inconel 718 substrate. Friction coefficients and wear traces of both coated and non-coated surfaces are drastically reduced at higher temperature of 538°C compared with those at room temperature. At high temperature, the brittle oxides such as CoO, Co₃O₄, MoO₂, MoO₃ are formed rapidly on the sliding surfaces, and the brittle oxide phases are easily attrited by reciprocating slides at high temperature through complicated mixed wear mechanisms. The sliding surfaces are worn by the mixed mechanisms such as oxidative wear, abrasion, slurry erosion. The brittle oxide particles and melts and partial-melts play roles as solid and liquid lubricant reducing friction coefficient and wear. These show that the coating is highly recommendable for the durability improvement coating on the surfaces vulnerable to frictional heat and wear.