• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.3
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• pp.87-92
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• 1997

Inductively coupled Cl$_{2}$ plasma has been studied to etch Pt thin films, which hardly form volatile compound with any reactive gas at normal process temperature. Low etch rate and residue problems are frequently observed. For higher etch rate, high density plasma and higher process temperature is adopted observed. For higher etch rate, high density plasma and higher process temperature is adopted and thus SiO$_{2}$ is used as for patterning mask instead of photoresist. The effect of O$_{2}$ or Ar addition to Cl$_{2}$ was investigated, and the chamber pressure, gas flow rate, surce RF power and bias RF power are also varied to check their effects on etch rate and selectivity. The major etching mechanism is the physical sputtering, but the ion assisted chemical raction is also found to be a big factor. The proposs can be optimized to obtain the etch rate of Pt up to 200nm/min and selectivity to SiO$_{2}$ at 2.0 or more. Patterning of submicron Pt lines are successfully demonstrated.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.188-189
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• 2007

The etching characteristics of $Al_2O_3$ films using the inductively coupled plasma (ICP) was investigated. The etch gas was the mixture of $BCl_3$ and He. The effect of ICP source and bias powers on etch rate and etch selectivity to polycrystalline Si was investigated in the etch process of $Al_2O_3$. The etch rate of $Al_2O_3$ film was 23nm/min when the source power and bias power were 600W and 60W, respectively. The results also indicated that the etch selectivity to polycrystalline Si could not be enhanced to be higher than 1.0 by changing the ICP source power and bias power, under the experimental conditions used in the present work. Based on plasma parameters extracted from Langmuir probe data, the etching mechanism of $Al_2O_3$ film was discussed in detail.

• Transactions on Electrical and Electronic Materials
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• v.14 no.2
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• pp.67-70
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• 2013

In this study, we changed the input parameters (gas mixing ratio, RF power, DC bias voltage, and process pressure), and then monitored the effect on TiN etch rate and selectivity with $SiO_2$. When the RF power, DC-bias voltage, and process pressure were fixed at 700 W, - 150 V, and 15 mTorr, the etch rate of TiN increased with increasing $CF_4$ content from 0 to 20 % in $CF_4$/Ar plasma. The TiN etch rate reached maximum at 20% $CF_4$ addition. As RF power, DC bias voltage, and process pressure increased, all ranges of etch rates for TiN thin films showed increasing trends. The analysis of x-ray photoelectron spectroscopy (XPS) was carried out to investigate the chemical reactions between the surfaces of TiN and etch species. Based on experimental data, ion-assisted chemical etching was proposed as the main etch mechanism for TiN thin films in $CF_4$/Ar plasma.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.6
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• pp.445-448
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• 2011

In this study, the etching characteristics of $Al_2O_3$ thin films were investigated using an ICP (inductively coupled plasma) of $BCl_3$/Ar gas mixture. The etch rate of $Al_2O_3$ thin films as well as the $SiO_2/Al_2O_3$ etch selectivity were measured as functions of $BCl_3$/Ar mixing ratio (0~100% Ar) at a constant gas pressure (10 mTorr), total gas flow rate (40 sccm), input power (800 W) and bias power (100 W). The behavior of the $Al_2O_3$ etch rate was shown to be quite typical for ion-assisted etch processes with a dominant chemical etch pathway. To analyze the etching mechanism using DLP (double langmuir probe), OES (optical emission spectroscopy) and surface analysis using XPS (x-ray photoelectron spectroscopy) were carried out.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.17-18
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• 2007

The etching characteristics of Zinc Oxide (ZnO) and etch selectivity of ZnO to $SiO_2\;in\;BCl_3$/Ar plasma were investigated. It was found that ZnO etch rate shows a non-monotonic behavior with increasing both Ar fraction in $BCl_3$ plasma, RF power, and gas pressure. The maximum ZnO etch rate of 50.3 nm/min was obtained for $BCl_3$ (80%)/Ar(20%) gas mixture. The plasmas were characterized using optical emission spectroscopy (OES) analysis measurements while chemical state of etched surfaces was investigated with X-ray photoelectron spectroscopy (XPS). From these data the suggestions on the ZnO etch mechanism were made.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.83-84
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• 2007

$BCl_3$/Ar ICP 플라즈마를 이용한 $ZrO_2$ 박막의 식각 메카니즘이 실험 결과와 모델링을 통해 연구되었다. Ar 가스의 증가에 따라, $ZrO_2$의 식각 속도는 선형 변화의 경향을 보이지 않았고, Ar의 약 30% - 35%에서 41.4nm/min의 최대의 속도를 나타내었다. Langmuir probe 측정과 plasma 모델링 결과로부터, $BCl_3$/Ar 가스 혼합비가 플라즈마 파라미터와 active species의 형성에 큰 영향을 미침을 확인하였다. 한편 surface kinetics 모델링 결과로부터, $ZrO_2$의 식각 속도는 ion-assisted chemical reaction mechanism 에 의해 결정됨을 확인하였다.

• Journal of the Korean Ceramic Society
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• v.49 no.4
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• pp.328-332
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• 2012

Etch rates of Si and high purity SiC have been compared for various fluorocarbon plasmas. The relative plasma resistance of SiC, which is defined as the etch rate ratio of Si to SiC, varied between 1.4 and 4.1, showing generally higher plasma resistance of SiC. High resolution X-ray photoelectron analysis revealed that etched SiC has a surface carbon content higher than that of etched Si, resulting in a thicker fluorocarbon polymer layer on the SiC surface. The plasma resistance of SiC was correlated with this thick fluorocarbon polymer layer, which reduced the reaction probability of fluorine-containing species in the plasma with silicon from the SiC substrate. The remnant carbon after the removal of Si as volatile etch products augments the surface carbon, and seems to be the origin of the higher plasma resistance of SiC.

• Applied Science and Convergence Technology
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• v.23 no.4
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• pp.169-178
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• 2014

Fluid model based numerical analysis is done to simulate a low damage etch back system for 20 nm scale semiconductor fabrication. Etch back should be done conformally with very high material selectivity. One possible mechanism is three steps: reactive radical generation, adsorption and thermal desorption. In this study, plasma generation and transport steps are analyzed by a commercial plasma modeling software package, CFD-ACE+. Ar + $CF_4$ ICP was used as a model and the effect of reactive gas inlet position was investigated in 2D and 3D. At 200~300 mTorr of gas pressure, separated gas inlet scheme is analyzed to work well and generated higher density of F and $F_2$ radicals in the lower chamber region while suppressing ions reach to the wafer by a double layer conducting barrier.

• Journal of the Korean Ceramic Society
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• v.53 no.3
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• pp.349-353
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• 2016

We prepared a number of reaction-bonded silicon carbides (RBSCs) made from various mixing ratios of raw SiC particles, and investigated their microstructure and etch characteristics by Reactive Ion Etch (RIE). Increasing the amount of $9.5{\mu}m$-SiC particles results in a microstructure with relatively coarser Si regions. On the other hand, increasing that of $2.6{\mu}m$-SiC particles produces much finer Si regions. The addition of more than 50 wt% of $2.6{\mu}m$-SiC particles, however, causes the microstructure to become partially coarse. We also evaluated their etching behaviors in terms of surface roughness (Ra), density and weight changes, and microstructure development by employing Confocal Laser Scanning Microscope (CLSM) and Scanning Electron Microscope (SEM) techniques. During the etching process of the prepared samples, we confirmed that the residual Si region was rapidly removed and formed pits isolating SiC particles as islands. This leads to more intensified ion field on the SiC islands, and causes physical corrosion on them. Increased addition of $2.6{\mu}m$-SiC particles produces finer residual Si region, and thus decreases the surface roughness (Ra.) as well as causing weight loss after etching process by following the above etching mechanism.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.477-477
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• 2008

For more than three decades, the gate dielectrics in CMOS devices are $SiO_2$ because of its blocking properties of current in insulated gate FET channels. As the dimensions of feature size have been scaled down (width and the thickness is reduced down to 50 urn and 2 urn or less), gate leakage current is increased and reliability of $SiO_2$ is reduced. Many metal oxides such as $TiO_2$, $Ta_2O_4$, $SrTiO_3$, $Al_2O_3$, $HfO_2$ and $ZrO_2$ have been challenged for memory devices. These materials posses relatively high dielectric constant, but $HfO_2$ and $Al_2O_3$ did not provide sufficient advantages over $SiO_2$ or $Si_3N_4$ because of reaction with Si substrate. Recently, $HfO_2$ have been attracted attention because Hf forms the most stable oxide with the highest heat of formation. In addition, Hf can reduce the native oxide layer by creating $HfO_2$. However, new gate oxide candidates must satisfy a standard CMOS process. In order to fabricate high density memories with small feature size, the plasma etch process should be developed by well understanding and optimizing plasma behaviors. Therefore, it is necessary that the etch behavior of $HfO_2$ and plasma parameters are systematically investigated as functions of process parameters including gas mixing ratio, rf power, pressure and temperature to determine the mechanism of plasma induced damage. However, there is few studies on the the etch mechanism and the surface reactions in $BCl_3$ based plasma to etch $HfO_2$ thin films. In this work, the samples of $HfO_2$ were prepared on Si wafer with using atomic layer deposition. In our previous work, the maximum etch rate of $BCl_3$/Ar were obtained 20% $BCl_3$/ 80% Ar. Over 20% $BCl_3$ addition, the etch rate of $HfO_2$ decreased. The etching rate of $HfO_2$ and selectivity of $HfO_2$ to Si were investigated with using in inductively coupled plasma etching system (ICP) and $BCl_3/Cl_2$/Ar plasma. The change of volume densities of radical and atoms were monitored with using optical emission spectroscopy analysis (OES). The variations of components of etched surfaces for $HfO_2$ was investigated with using x-ray photo electron spectroscopy (XPS). In order to investigate the accumulation of etch by products during etch process, the exposed surface of $HfO_2$ in $BCl_3/Cl_2$/Ar plasma was compared with surface of as-doped $HfO_2$ and all the surfaces of samples were examined with field emission scanning electron microscopy and atomic force microscope (AFM).