• 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.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.12
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• pp.1051-1056
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• 2008

In this study, the investigations of the TiN etching characteristics were carried out with addition of $Cl_2$ gas in an inductively coupled $BCl_3$-base plasma system. Dry etching of the TiN was studied by varying the etching parameters including $Cl_2$ gas addition ratio, RF power, DC-bias voltage and pressure. The etch rate of TiN thin film was maximum when the $Cl_2$ gas addition flow was 2 sccm with fixed other conditions. As the RF power DC-bias voltage were increased, the etch rate of TiN thin film showed increasing tendency. $BCl_3/Cl_2$/Ar plasmas were characterized by optical emission spectroscopy (OES) analysis. The chemical reaction on the surface of the etched TiN films was investigated with X-ray photoelectron spectroscopy (XPS).

• 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.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.10a
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• pp.221-222
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• 2009

유도결합 플라즈마 (Inductively Coupled Plasma) 장비를 이용하여 각종 공정조건들에 따른 $TiO_2$의 식각 특성을 연구하였다. $BCl_3$/Ar 가스의 혼합비, 공정 압력 등을 공정 변수들로 정하였다. 공정 변수가 가스 혼합비일 경우 $BCl_3$ 가스의 비율이 25 % 일 경우 높은 식각률을 보였다. 또한 X-ray photoelectron spectroscopy를 이용하여 분석한 결과, $TiO_2$의 식각 메커니즘은 화학적인 영향보다는 물리적인 영향을 더 많이 받는다.

• Journal of Surface Science and Engineering
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• v.41 no.3
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• pp.83-87
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• 2008

This study described the effects of RF power, DC bias voltage, chamber pressure and gas mixing ratio on the etch rates of TiN thin film and selectivity of TiN thin film to $SiO_2$ with $BCl_3$/Ar gas mixture. When the gas mixing ratio was $BCl_3$(20%)/Ar(80%) with other conditions were fixed, the maximum etch rate of TiN thin film was 170.6 nm/min. When the DC bias voltage increased from -50 V to -200 V, the etch rate of TiN thin film increased from 15 nm/min to 452 nm/min. As the RF power increased and chamber pressure decreased, the etch rate of TiN thin film showed an increasing tendency. When the gas mixing ratio was $BCl_3$(20%)/Ar(80%) under others conditions were fixed, the intensity of optical emission spectra from radical or ion such as Ar(750.4 nm), $Cl^+$(481.9 nm) and $Cl^{2+}$(460.8 nm) was highest. The TiN thin film was effectively removed by the chemically assisted physical etching in $BCl_3$/Ar ICP plasma.

• Proceedings of the KIEE Conference
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• 2003.10a
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• pp.309-311
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• 2003

The effects of etch parameters on dry etching of BLT thin films were investigated with ICP etch system in $Cl_2$/Ar and $BCl_2/Cl_2$/Ar gas. The etch rate and etch selectivity of BLT films were examined as a function of gas concentration, ICP power, bias power, and pressure. The maximum etch rates of 191.1 nm/min was obtained at the mixed etch condition of $BCl_3(20%)/Cl_2$/Ar, 700 W ICP RF power, 12 mTorr pressure and 400 W substrate RF power. As ICP power and rf power increased, the etch rate of BLT increased. As pressure increased, the etch rate of BLT decreased. The changes of radicals in both $Cl_2$/Ar and $BCl_3/Cl_2$/Ar plasma were measured with using optical emission spectroscopy (OES).

• Proceedings of the Materials Research Society of Korea Conference
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• 1999.11a
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• pp.142-142
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• 1999

• Journal of Surface Science and Engineering
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• v.41 no.6
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• pp.269-273
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• 2008

The etch of $(Na_{0.5}K_{0.5})NbO_3$ (NKN) thin film was performed in $BCl_3/Cl_2/Ar$ inductively coupled plasma. It was found that the 1sccm addition $BCl_3$ (5%) into $Cl_2/Ar$ plasma caused a non-monotonic behavior of the NKN etch rate. The maximum etch rate of NKN was 95.3 nm/min at $BCl_3$ (1 sccm)/$Cl_2$ (16 sccm)/Ar (4 sccm), 800 W ICP power, 1 Pa pressure and 400 W bias power. The NKN etch rate shows a monotonic behavior a s the bias power increases. The analysis of the narrow scan spectra of XPS for both a s-deposited and etched NKN films allowed one to assume ion assisted etch mechanism. The most probable reason for the maximum etch rate can be defined as a concurrence of chemical and physical etch pathways.

• 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).

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.31-31
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• 2000

Al2O3는 높은 화학적, 열적 안정성으로 인하여 미세전자 산업에서 절연막이나 광전자소자의 재료로써 널리 이용되고 있다. 특히, 사파이어는 고위도의 LED, 청색 LD의 재료인 GaN 계열의 III-Nitride 물질을 성장시킬 때 필요한 기판으로 보편적으로 사용되고 있다. 이러한 GaN계열의 광소자 제조에서 사파이어 기판을 적용시 지적되는 문제점들 중의 하나는 소자제조 후 사파이어의 결정 구조 및 높은 경도에 의해 나타나는 cutting 및 backside의 기계적 연마가 어렵다는 것이다. 최근에는 이온빔 식각이나 이온 주입 후 화학적 습식 시각, reactive ion etching을 통한 사파이어의 건식 식각이 소자 분리 및 backside 공정을 우해 연구되고 있다. 그러나 이러한 방법을 이용한 사파이어의 식각속도는 일반적으로 15nm/min 보다 작다. 높은 식각율과 식각후 표면의 작은 거칠기를 수반한 사파이어의 플라즈마 식각은 소자 제조 공정시 소자의 isolation 및 lapping 후 연마 공정에 이용할 수 있다. 본 연구에서는 평판 유도결합형 플라즈마를 이용하여 Cl2/BCL3/Ar 의 가스조합, inductive power, bias voltage, 압력, 기판온도의 다양한 공정 변수를 통하여 (0001) 사파이어의 식각특성을 연구하였다. 사파이어의 식각속도는 inductive power, bias voltage, 그리고 기판 온도가 증가할수록 증가하였으며 Cl2에 BCl3를 50%이하로 첨가할 때 BCl3 첨가량이 증가할수록 식각속도 및 식각마스크(photoresist)와의 식각선택비가 증가하는 것을 관찰하였다. 또한, Cl3:BCl3=1:1의 조건에 따라 Ar 첨가에 따른 식각속도 및 표면 거칠기를 관찰하였다. 본 연구의 최적 식각조건인 40%Cl2/40%BCl3/20%Ar, 600W의 inductive power, -300V의 bias voltage, 30mTorr의 압력, 기판온도 7$0^{\circ}C$에서 270nm/min의 사파이어 식각속도를 얻을수 있었다. 그리고 이러한 식각조건에서 표면의 거치기를 줄일수 있었다. 사파이어 식각은 보편적인 사파이어 lapping 공정시 수반되어 형성된 표면의 거치기를 줄이기 위한 마지막 공정에 응용될수 있다. 사파이어의 식각시 나타나는 식각 부산물은 플라즈마 진단방비인 optical emission spectroscopy (OES)를 통하여 관찰하였고, 식각시 사파이어의 표면성분비 변화 및 표면의 화학적 결합은 X-ray photoelectron spectroscopy(XPS)를 사용하여 측정하였다. 시각 전, 후의 표면의 거칠기를 scanning electron microscopy(SEM)을 통하여 관찰하였다.