• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.5
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• pp.388-392
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• 2002

In this work, the etching of $CeO_2$ thin films has been performed in an inductively coupled $Ar/CF_4/Cl_2$ plasma. The highest etch rate of the $CeO_2$ thin film ws 250 ${\AA}/min$ and the selectivity of CeO$_2$to SBT was 0.4 at a 10% additive $Cl_2$ into Ar/($Ar+CF_4$)gas mixing ratio of 0.8. From result of X-ray photoelectron spectroscopy (XPS) analysis, there are Ce-Cl and Ce-F bonding by chemical reaction between Cl, F and Ce. During the etching of $CeO_2$ thin films in $Ar/CF_4/Cl_2$ plama, Ce-Cl and Ce-F bond is formed, and these prodcuts can be removed by the physical bombardment of Ar ions. The 10% additive $Cl_2$ into the Ar/($Ar+CF_4$)gas mixing ratio of 0.8 could enhance the reaction between Cl, F and Ce.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05b
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• pp.7-11
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• 2002

In this study, Au thin films were etched with a $Cl_2/Ar$ gas combination in an in an inductively coupled plasma. The etch properties were measured for different gas mixing ratios of $Cl_2/(Cl_2+Ar)$ while the other process conditions were fixed at rf power (700 W), dc bias voltage (150 V), and chamber pressure (15 mTorr). The highest etch rate of the Au thin film was 3500 $\AA/min$ and the selectivity of Au to $SiO_2$ was 4.38 at a $Cl_2/(Cl_2+Ar)$ gas mixing ratio of 0.2. The surface reaction of the etched Au thin films was investigated using x-ray photoelectron spectroscopy (XPS) analysis. There is Au-Cl bonding by chemical reaction between Cl and Au. During the etching of Au thin films in $Cl_2/Ar$ plasma, Au-Cl bond is formed, and these products can be removed by the physical bombardment of Ar ions. In addition, Optical emission spectroscopy (OES) were investigated to analyze radical density of Cl and Ar in plasma. The profile of etched Au investigated with scanning electron microscopy (SEM).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05c
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• pp.174-177
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• 2003

$Cl_2$ 플라즈마를 이용한 BLT 박막의 식각에서 Ar 가스의 첨가에 따른 식각 속도, 선택비 및 식각 형상의 변화에 대하여 관찰하였다. BLT 박막의 식각 속도는 100% Ar 플라즈마에서 100 % $Cl_2$ 플라즈마에서의 식각 속도보다 약 1.5배정도 빨랐으며, 80% Ar/20% $Cl_2$ 조건에서 $503{\AA}/min$ 최대 식각의 최대 시각 속도를 얻었다. RF 전력과 직류 바이어스 전압을 증가함에 따라 식각 속도는 증가하였으며, $Ar/Cl_2$ 플라즈마의 식각 속도가 $Cl_2$ 플라즈마의 식각 속도 보다 높았다. 식각 공정 변수의 변화에 의한 플라즈마 변수가 BLT 식각 속도에 미치는 영향을 관찰하기 위하여 LP(Lanmuir porbe)와 OES(optical emission spectroscopy)분석을 수행하였다. Ar 첨가량이 증감함에 따라 LP 분석에서 전자의 온도는 증가하였으나 전자밀도는 감소하였다. 이는 Ar의 이온화 준위가 Cl 보다 높기 때문에 이온화 윷이 낮아지기 때문으로 판단된다, 또한, OES 분석에서 Ar 첨가량이 증가함에 따라 Cl 원자의 부피 밀도는 감소하였다. Ar 첨가에 의한 BLT 박막의 식각 속도의 변화와 LP 및 OES 분석을 고려하면, BLT 박막은 화학적 식각의 도움을 받는 무리적 식각에 의하여 식각됨을 확인하였다,

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.12
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• pp.1011-1015
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• 2002

In this study, Au thin films were etched with a Cl$_2$/Ar gas combination in an inductively coupled plasma. The highest etch rate of the Au thin film was 3500 A/min at a Cl$_2$/(Cl$_2$+Ar) gas mixing ratio of 0.2. The surface reaction of the etched Au thin films was investigated using x-ray photoelectron spectroscopy (XPS) analysis. There is Au-Cl bonding by chemical reaction between Cl and Au. During the etching of Au thin films in Cl$_2$/Ar plasma, Au-Cl bond is formed, and these products can be removed by the physical bombardment of Ar ions[l].

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.62-65
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• 2001

$SrBi_2Ta_2O_{9}$ thin films were etched in inductively coupled $Cl_{2}$/$CF_{4}$/Ar plasma. The maximum etch rate was 1060 $\AA\textrm{m}$/min in $Cl_{2}$/$CF_{4}$/Ar (80). The chemical reactions on the etched surface were studied with x-ray photoelectron spectroscopy. The etching of SBT thin films in $Cl_{2}$/$CF_{4}$/Ar were etched by chemically assisted reactive ion etching. The small addition of $Cl_2$ into $CF_4$(20)/Ar(80) plasma will decrease the fluorine radicals and the increase Cl radical.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1512-1514
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• 2001

In this work, PZT thin films were etched as a function of $Cl_2$/Ar and additive $CF_4$ into $Cl_2$(80%)/Ar(20%). The etch rates of PZT films were 1600 $\AA$/min at $Cl_2$(80%)/Ar(20%) gas mixing ratio and 1973 $\AA$/min at 30% additive $CF_4$ into $Cl_2$(80%)/Ar(20%). Therefore the etch rate of PZT in $CF_4/Cl_2/Ar$ plasma is faster than in $Cl_2$/Ar. From XPS and SIMS analysis, metal halides and C-O, FCI and $CClF_2$ were detected. The etching of PZT films in Cl-based plasma is primarily chemically assisted ion etching and the remove of nonvolatile etch byproducts is the dominant step. Consequently, we suggest that the increase of Cl radicals and the volatile oxy-compound such as $CO_y$ are made by adding $CF_4$ into $Cl_2$/Ar plasma. Therefore, the etch rate of PZT in $CF_4/Cl_2/Ar$ plasma is faster than in $Cl_2$/Ar. The etched profile of PZT films was obtained above 70$^{\circ}$ by the SEM micrograph.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.58-61
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• 2002

SBT thin films were etched at different content of Cl$_2$in Cl$_2$/Ar plasma. We obtained the maximum etch rate of 883 ${\AA}$/min at Cl$_2$(20%)/Ar(80%). As Cl$_2$ gas increased in Cl$_2$/Ar plasma, the etch rate decreased. The maximum etch rate may be explained by variation of volume density for Cl atoms and by the concurrence of two etching mechanisms such as physical sputtering and chemical reaction with formation of low-volatile products, which can be desorbed only by ion bombardment. The variation of volume density for Cl, F and Ar atoms and ion current density were measured by the optical emission spectroscopy and Langmuir probe. To evaluate the physical damage due to plasma, X-ray diffraction and atomic force microscopy analysis carried out. After etching process, P-E hysteresis loops were measured by ferroelectric workstation.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.5
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• pp.29-35
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• 1999

Inductively coupled plsama etching of platinum thin film was studied using $O_2$ addition to $Cl_2$/Ar gas plasma. In this study, Pt etching mechanism was investigated with Ar/$Cl_2$ /$O_2$ gas plasma by using XPS and QMS. Ion current density was measured with Ar/$Cl_2$ /$O_2$ gas plasma by using single Langmuir probe. It was confirmed by using QMS and single Langmuir probe that Cl and Ar species rapidly decreased and ion current density was also decreased with increasing $O_2$ gas ratios. These results implied that the decrease of Pt etch rate is due to the decrease of reactive species ans ion current density with increasing $O_2$ gas mixing ratios. A maximum etch rate of 150nm/min and the oxide selectivity of 2.5 were obtained at Ar/$Cl_2$ /$O_2$ flow rate of 50 seem, RF power of 600 W, dc bias voltage of 125 V, and the total pressure of 10 mTorr.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.26-29
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• 2001

$SrBi_2Ta_2O_{9}$ thin films were etched at high-density $Cl_2/CF_4/Ar$ in inductively coupled plasma system. The etching of SBT thin films in $Cl_2/CF_4/Ar$ were chemically assisted reactive ion etching. The maximum etch rate was 1300 $\AA$/min at 900W in $Cl_2(20)/CF_4(20)/Ar(80)$. As rf power increase, radicals (F, Cl) and ion(Ar) increase. The influence of plasma induced damage during etching process was investigated in terms of the surface morphology and th phase of X-ray diffraction. The chemical residue was investigated with secondary ion mass sperometry.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.11
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• pp.18-24
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• 2000

(Ba,Sr)$TiO_3$ thin films have attracted great interest as new dielectric materials of capacitors for ultra-large-scale integrated dynamic random access memories (ULSI-DRAMs) such as 1 Gbit or 4 Gbit. In this study, inductively coupled $BCl_3/Cl_2/Ar$ plasmas was used to etch (Ba,Sr)$TiO_3$ thin films. RF power/dc bias voltage=600 W/-250 V and chamber pressure was 10 mTorr. The $Cl_2/(Cl_2+Ar)$ was fixed at 0.2 the (Ba,Sr)$TiO_3$ thin films were etched adding $BCl_3$. The highest (Ba,Sr)$TiO_3$ etch rate is $480{\AA}/min$ at 10 % $BCl_3$ to $Cl_2/Ar$. The change of Cl, B radical density measured by optical emission spectroscopy(OES) as a function of $BCl_3$ percentage in $Cl_2/Ar$. The highest Cl radical density was shown at the addition of 10% $BCl_3$ to $Cl_2/Ar$. To study on the surface reaction of (Ba, Sr)$TiO_3$ thin films was investigated by XPS analysis. Ion bombardment etching is necessary to break Ba-O bond and to remove $BaCl_2$. There is a little chemical reaction between Sr and Cl, but Sr is removed by physical sputtering. There is a chemical reaction between Ti and Cl, and $TiCl_4$ is removed with ease. The cross-sectional of (Ba,Sr)$TiO_3$ thin film was investigated by scanning electron microscopy (SEM), the etch slope is about 65~70$^{\circ}$.