• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.544-547
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• 2006

In this study, the characteristics of large area internal linear ICP sources of $1,020mm{\times}920mm$ (substrate area is $880mm{\times}660mm$) were investigated using a multiple linear antennas with U-type parallel connection. Using the multiple linear antennas with U-type parallel connection, a high plasma density of $2{\times}10^{11}/cm^3$ and a high power transfer efficiency of about 88% could be obtained at 5kW of RF power and with 20mTorr Ar. A low plasma potential of less than 26V and a low electron temperature of $2.6{\sim}3.2eV$ could be also obtained. The measured plasma uniformity on the substrate size of 4th generation $(880mm{\times}660mm)$ was about 4%, therefore, it is believed that the multiple linear antennas with U-type parallel connection can be successfully applicable to the large area flat panel display processing.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.20-20
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• 2000

Back-propagation neural network (BPNN) is the most prevalently used paradigm in modeling semiconductor manufacturing processes, which as a neuron activation function typically employs a bipolar or unipolar sigmoid function in either hidden and output layers. In this study, applicability of another linear function as a neuron activation function is investigated. The linear function was operated in combination with other sigmoid functions. Comparison revealed that a particular combination, the bipolar sigmoid function in hidden layer and the linear function in output layer, is found to be the best combination that yields the highest prediction accuracy. For BPNN with this combination, predictive performance once again optimized by incrementally adjusting the gradients respective to each function. A total of 121 combinations of gradients were examined and out of them one optimal set was determined. Predictive performance of the corresponding model were compared to non-optimized, revealing that optimized models are more accurate over non-optimized counterparts by an improvement of more than 30%. This demonstrates that the proposed gradient-optimized teaming for BPNN with a linear function in output layer is an effective means to construct plasma models. The plasma modeled is a hemispherical inductively coupled plasma, which was characterized by a 24 full factorial design. To validate models, another eight experiments were conducted. process variables that were varied in the design include source polver, pressure, position of chuck holder and chroline flow rate. Plasma attributes measured using Langmuir probe are electron density, electron temperature, and plasma potential.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.05a
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• pp.124-125
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• 2012

Korea institute of materials science (KIMS) use a linear deposition source called as a closed drift linear plasma source (CDLPS) as well as dual magnetron sputtering (DMS) to deposit SiOxCyHz films in $HMDSO/O_2$ plasma. The CDLPS generates linear plasma using closed drifting electrons and can reduce device degradations due to energetic ion bombardments on organic devices such as organic photovoltaic and organic light emission diode by controlling an ion energy. The deposited films are investigated by Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). Optical emission spectroscopy (OES) is used to measure relative radical populations of dissociation and recombination products such as H, CH, and CO in plasma. And SiOx film is applied to a barrier film on organic photovoltaic devices.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.6
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• pp.514-524
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• 2016

This work suggests a study on 5 kW plasma power supply design and reactor capacitance estimation algorithm for a wide range of linear output control to operate a plasma reactor. The suggested study is designed to use a two-stage circuit and control the full-bridge circuit of the two-stage circuit using the buck converter output voltage of the single-stage circuit. The switching frequency of the full-bridge circuit is designed to operate through high-frequency switching and obtain maximum output using LC parallel resonance. Soft switching technique(ZVS) is used to reduce the loss caused by high-frequency switching, and duty control of the buck converter is applied to control a wide range of linear output. The internal capacitance of the reactor cannot easily be extracted, and thus, the reactor cannot be operated in an optimized resonant state. To address this issue, this work designs the internal capacitance of the reactor such that estimations can be performed with the developed reactor capacitance estimation algorithm applied to the internal capacitance of the reactor. A 5 kW plasma power supply is designed for a wide range of linear output control, and the validity of the study on the reactor capacitance estimation algorithm is verified.

• Applied Science and Convergence Technology
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• v.26 no.2
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• pp.34-41
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• 2017

A 2.45 GHz microwave plasma with linear antenna has been prepared for hydrophobic and wear-resistible surface coating of carbon steel. Wear-resistible properties are required for the surface protection of cutting tools and achieved by depositing a hydrogenated amorphous carbon film on steel surface through linear microwave plasma source that has $TE_{10}-TEM$ waveguide. Compared to the existing RF plasma source driven by 13.56 MHz, linear microwave plasma source can easily generate high density plasma and provide faster deposition rate and wider process windows. In this study, $Ar/CH_4$ gas mixtures are used for hydrogenated amorphous carbon film deposition. When microwave power of 1000 W is applied, 40 cm long uniform $Ar/CH_4$ plasma could be obtained in gas pressure of 200~400 mTorr. The Vickers hardness measurement of hydrogenated amorphous carbon film on steel surface was evaluated. It was found the optimized deposition condition at $Ar:CH_4=25:25$ sccm, 300 mTorr with microwave power of 1000W and RF bias power of 100W. By deposition of hydrogenated amorphous carbon film, contact angle on steel surfaces increases from $43.9^{\circ}$ to $93.2^{\circ}$.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.158.1-158.1
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• 2013

Microwave는 일반적으로 300 [MHz]~30 [GHz] 사이의 주파수를 가지는 전파로 1 [m] 이하의 파장을 가진다. Microwave를 이용한 플라즈마의 경우 낮은 이온 에너지, 효율적인 전자 가열, 넓은 동작압력 범위, 높은 밀도 등의 장점을 가지고 있어 PECVD(Plasma Enhanced Chemical Vapor Deposition)에 적합한 플라즈마 소스라고 할 수 있다. 또한 Microwave는 파장의 길이가 증착이 이루어지는 진공 챔버의 길이보다 매우 작기 때문에 대면적 적용성이 용이하므로 현재 많은 연구가 이루어지고 있다. 본 연구에서는 Fluid Simulation을 통해 Maxwell's equation, continuity equation, electromagnetic wave equation 등을 이용하여 Microwave의 파워 및 압력에 따른 플라즈마 parameter를 계산하고, 자체 제작한 Linear microwave plasma 장치에서 정전 탐침(Langmuir Probe)을 이용하여 플라즈마 Parameter를 측정하였다. 또한 Simulation 결과와 실험결과를 비교 분석하였다.

• Journal of the Semiconductor & Display Technology
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• v.17 no.2
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• pp.16-19
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• 2018

The development speed of semiconductor and display device manufacturing technology is growing faster than the development speed of process equipment. So, there is a growing need for process diagnostic technology that can measure process conditions in real time and directly. In this study, a plasma diagnosis was carried out using impedance variation due to the plasma discharge. Variation of the measurement impedance appears as a voltage change at the reference impedance, and the plasma density is calculated using this. The above experiment was conducted by integrating the plasma diagnosis system and the linear atmospheric pressure DBD plasma source. It was confirmed that plasma density varies depending on various parameters (gas flow rate, $Ar/O_2$ mixture ratio, Input power).

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.933-936
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• 2007

An inductively coupled plasma source with internaltype linear inductive antennas named as "multiple Utype antenna" was developed for the substrate size of $2,300mm\;{\times}\;2,000mm$. High density plasmas on the order of $1.18\;{\times}\;10^{11}\;cm^{-3}$ could be obtained and the RF power of 8kW with good plasma stability.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.31.2-31
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• 2001

A real-time control strategy is presented for plasma control Rather than in-situ plasma variables, this is based on realtime measurements of two electrical positions that correspond to two match motors. Using the rf match monitor system, the positions were collected. The process of impedance matching was identified with variations in process factors, including rf power, pressure, and O$_2$ flow rate. A state-space model was obtained basing on autoregressive moving average model. For this model, a linear quadratic regulator was designed and applied. Simulation results revealed that match positions could accurately be regulated to follow certain positions arbitrarily chosen.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.4
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• pp.567-572
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• 2015

Discharge characteristics of linear microwave plasma were investigated by using fluid simulation of 2D axis-symmetry based on finite elements method. The microwave power was 2.45 GHz TEM mode and transmitted through linear antenna. Resistive power and pressure were considered simulation variables and argon was used for working gas. A decrease of electron density along the quartz tube was observed in low power condition but relatively uniform plasmas were generated in chamber by increasing the resistive power. The electron temperature was highly detected near the surface of quartz tube because the electron was heated only dielectric surface. The power transmission efficiency decreased and characteristics of surface plasma were observed in high electron density condition.