450 ㎜ 웨이퍼 공정용 System의 기하학적 구조에 따른 플라즈마 균일도 모델링 분석

양원균(Wonkyun Yang),주정훈(Junghoon Joo) 한국진공학회(ASCT) 2010 Applied Science and Convergence Technology Vol.19 No.3

450 ㎜의 웨이퍼 공정용 플라즈마 장비의 개발을 위하여 안테나 형상, 챔버의 직경, 웨이퍼까지의 거리에 따른 플라즈마 균일도를 Ar과 CF4에 대하여 축대칭 2차원으로 수치 모델링하였다. 챔버의 종횡비를 직경, 기판까지의 거리, 배기구의 면적으로 나누어서 결정하고 여기에 안테나 구조를 변경하여서 최적의 플라즈마 균일도를 갖는 조건을 도출하였다. Drift diffusion식과 준중성 조건을 이용한 간략화를 이용하였으며 표면 재결합과 식각 반응을 이온에너지의 함수로 처리하였다. 반응기판 표면에서의 플라즈마 밀도 균일도는 기판 홀더와 챔버 벽면과의 거리, 기판과 소스와의 거리가 멀수록 좋아졌으며, 안테나의 디자인이 4 turn으로 1층인 경우, 두 번째, 네 번째 turn만 사용하여 전류비 1 : 4에서 기판표면에서의 플라즈마 균일도를 4.7%까지 낮출 수 있었다. Ar과 CF₄의 반경 방향으로 전자 온도 균일도 50%, 전자 밀도 균일도 19%의 차이가 있었다. Asymmetric model for plasma uniformity by Ar and CF₄ was modeled by the antenna structure, the diameter of chamber, and the distance between source and substrate for the development of plasma equipment for 450 ㎜ wafer. The aspect ratio of chamber was divided by diameter, distance from substrate, and pumping port area. And we found the condition with the optimized plasma uniformity by changing the antenna structure. The drift diffusion and quasi-neutrality for simplification were used, and the ion energy function was activated for the surface recombination and etching reaction. The uniformity of plasma density on substrate surface was improved by being far of the distance between substrate wall and chamber wall, and substrate and plasma source. And when the antenna of only 2 turns was used, the plasma uniformity can improve from 20~30% to 4.7%.

직류 방전과 펄스 직류 방전에 의한 플라즈마 형상 관찰

양원균(Wonkyun Yang),주정훈(Junghoon Joo) 한국표면공학회 2009 한국표면공학회지 Vol.42 No.3

Effects of bipolar pulse driving frequency between 50 ㎑ and 250 ㎑ on the discharge shapes were analyzed by measuring plasma characteristics by OES (Optical Emission Spectroscopy) and Langmuir probe. Plasma characteristics were modeled by a simple electric field analysis and fluid plasma modeling. Discharge shapes by a continuous dc and bipolar pulsed dc were different as a dome-type and a vertical column-type at the cathode. From OES, the intensity of 811.5 ㎚ wavelength, the one of the main peaks of Ar, decreased to about 43% from a continuous dc to 100 ㎑. For increasing from 100 ㎑ to 250 ㎑, the intensity of 811.5 ㎚ wavelength also decreased by 46%. The electron density decreased by 74% and the electron temperature increased by 36% at the specific position due to the smaller and denser discharge shape for increasing pulse frequency. Through the numerical analysis, the negative glow shape of a continuous dc were similar to the electric potential distribution by FEM (Finite Element Method). For the bipolar pulsed dc, we found that the electron temperature increased to maximum 10 eV due to the voltage spikes by the fast electron acceleration generated in pre-sheath. This may induce the electrons and ions from plasma to increase the energetic substrate bombardment for the dense thin film growth.

Al doped ZnO 박막 증착을 위한 모듈레이티드 펄스 스퍼터링

양원균(Wonkyun Yang),주정훈(Junghoon Joo) 한국표면공학회 2012 한국표면공학회지 Vol.45 No.2

Modulated Pulse Power (MPP) magnetron sputtering is a new high-power pulsed magnetron sputtering(HPPMS) technology which overcomes the low deposition rate problem by modulating the pulse voltage shape, amplitude, and the duration. Highly ionized magnetron sputtering can be performed without arcing because it can be controlled as multiple steps of micro pulses within one overall pulse period in the range of 500-3,000 μs. In this study, the various waveforms of discharge voltage and current for micro pulse sets of MPP were investigated to find the possibility of controlling the strongly ionized plasma mode. Enhanced ionization of the sputtered metal atoms was obtained by OES. Large grained columnar structure can be grown by the strongly ionized plasma mode in the AZO deposition using MPP. In the most highly ionized deposition condition, the preferred orientation of (002) plane decreased, and the resistivity, therefore, increased by the plasma damage.

백색 LED 증착용 MOCVD 장치에서 유도가열을 이용한 기판의 온도 균일도 향상에 관한 연구

홍광기(Kwangki Hong),양원균(Wonkyun Yang),주정훈(Junghoon Joo),이승호(Seungho Lee),이태완(Tae-Wan Lee) 한국표면공학회 2010 한국표면공학회지 Vol.43 No.6

Deposition temperature uniformity of GaN based MQW (multiple quantum well) layers is an important key which affects the wavelength uniformity of white LEDs. Temperature uniformity was assessed by infrared images for both cases of a static and a rotating susceptor. Rotating the susceptor at 2.5 rpm over the induction heater gave 4.3% of temperature non-uniformity. Temperature distribution of the graphite susceptor over the induction heater was numerically modelled and agreed with experimental results.

원격 유도결합 플라즈마 시스템의 특성 해석

김영욱(Yeonguk Kim),양원균(Wonkyun Yang),주정훈(Junghoon Joo) 한국표면공학회 2008 한국표면공학회지 Vol.41 No.4

We have developed a numerical model for a remote ICP(inductively coupled plasma) system in 2D and 3D with gas distribution configurations and confirmed it by plasma diagnostics. The ICP source has a Cu tube antenna wound along a quartz tube driven by a variable frequency rf power source (1.9~3.2 ㎒) for fast tuning without resort to motor driven variable capacitors. We investigated what conditions should be met to make the plasma remotely localized within the quartz tube region without charged particles' diffusing down to a substrate which is 300 ㎜ below the source, using the numerical model. OES(optical emission spectroscopy), Langmuir probe measurements, and thermocouple measurement were used to verify it. To maintain ion current density at the substrate less than 0.1 ㎃/㎠, two requirements were found to be necessary; higher gas pressure than 100 mTorr and smaller rf power than 1 ㎾ for Ar.

UV/Ozone 복합 살균기의 살균력 개선 연구

지정은(Jungeun Jee),양원균(Wonkyun Yang),박은철(Eunchul Park),김강석(Kangsuk Kim),주정훈(Junghoon Joo) 한국표면공학회 2008 한국표면공학회지 Vol.41 No.2

We investigated sterilization characteristics of UV lights by counting the number of bacteria units with varying sterilization time and distance from the light source. We focused on an idea that UV light of 184.9 ㎚ could generate ozone and developed a new sterilizer. The UV -ozone duplex system sterilized bacteria faster than UV-only sterilizers. To reduce shadowing effects by target objects, we used UV transparent quartz plate as a support and put a reflecting plate. Distribution of UV irradiation intensity and ozone supply were analyzed by a 3D model and measured by a semiconductor UV sensor. But even with an Al reflector, multi-layered pens could not be treated properly from UV irradiation only. Ozone generating lamp could treat more uniformly multi-layered pens with a stirring fan by supplying ozone to shadowed surfaces.

수치모델과 고속 CCD 카메라를 이용한 세변기 표면 처리 효과 특성 해석

노지현(Jihyun Roh),도우리(Woori Do),양원균(Wonkyun Yang),주정훈(Junghoon Joo) 한국표면공학회 2011 한국표면공학회지 Vol.44 No.1

Numerical analysis is done to investigate the effect of surface treatment of a toilet on the cleanness. The surface treatment using plasma for the super-hydrophobic surface expects the self-cleaning effect of the toilet seat cover for preventing the droplets with a great quantity of bacteria during the toilet flushing after evacuation. In this study, the fluid analysis in the toilet during the flushing was performed by an ultrahigh-speed CCD camera with 1,000 frame/sec and the numerical modeling. And the spattering phenomenon from the toilet surface during urine was analyzed quantitatively by CFD-ACE+ with a free surface model and a mixed model of two fluids. If the surface tension of the toilet surface is weak, many urine droplets after collision bounded in spite of considering the gravity. The turbulence generated by the change of angle and velocity of urine and the variation of the collision phenomenon from toilet surface were modeled numerically.