• Proceedings of the IEEK Conference
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• 2001.06b
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• pp.37-40
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• 2001

The semiconductor's design rule becomes more stringent, hence the silicon-dioxide etching technique is important issue. In this work we compared the etching characteristics of different three types of Plasma source, Normal ICP, magnetized ICP and E-IC $P^{TM}$. The E-IC $P^{TM}$ source shows higher etch rate at lower pressure and this is advantageous for the fine pattern process. The etching characteristics were varied with external magnetic field frequency at I-lCP and this is examined with Nanospe $c^{TM}$ and SEM. We designed Langmuir probe system for time resolved diagnosis. ion density of E-ICP is varying periodically with the applied external magnetic field frequencyquency

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05e
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• pp.77-80
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• 2003

MEMS(Micro Electro Mechanical System) 기술에서 실리콘 식각기술의 중요성으로 플라즈마 식각기술의 개발이 꾸준히 진행되고 있다. 이중에서 ICP(Inductive Coupled Plasma)는 기존의 증착장치에 유도결합식 플라즈마를 추가로 발생시켜 증착막의 특성을 획기적으로 개선시키는 가장 최근에 개발된 기술이며, 이용에너지를 증가시키지 않고도 이용밀도를 높이고 이용업자들에 방향성을 가할 수 있는 새로운 플라즈마 기술로, 주로 MEMS 제조공정에 응용되고 있다. 본 연구에서는 STS-ICP $ASE^{HR}$을 이용하여 식각과 증착공정을 반복하여 식각을 하는 Bosch 식각에 관하여 연구하였다 STS-ICP $ASE^{HR}$ 장비의 Platen power, Coil power 및 Process pressure에 다양한 변화를 주어 각 변수에 따른 식각속도를 관찰하였다. 각 공정별 변수를 변화시킨 결과 Platen power 12W, Coil power 500W, 식각/Passivation Cycle 6/7sec 일 경우 식각속도는 $1.2{\mu}m$/min 이었고, Sidewall profile은 $90{\pm}0.7^{\circ}$로 나타나 매우 우수한 결과를 보였다.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.211-213
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• 2006

In this study, plasma etching process was modeled by using support vector machine (SVM). The data used in modeling were collected from the etching of silica thin films in inductively coupled plasma. For training and testing neural network, 9 and 6 experiments were used respectively. The performance of SVM was evaluated as a function of kernel type and function type. For the kernel type, Epsilon-SVR and Nu-SVR were included. For the function type, linear, polynomial, and radial basis function (RBF) were included. The performance of SVM was optimized first in terms of kernel type, then as a function of function type. Five film characteristics were modeled by using SVM and the optimized models were compared to statistical regression models. The comparison revealed that statistical regression models yielded better predictions than SVM.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.142.2-142.2
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• 2015

Plasma etch endpoint detection (EPD) of SiO2 and PR layer is demonstrated by plasma impedance monitoring in this work. Plasma etching process is the core process for making fine pattern devices in semiconductor fabrication, and the etching endpoint detection is one of the essential FDC (Fault Detection and Classification) for yield management and mass production. In general, Optical emission spectrocopy (OES) has been used to detect endpoint because OES can be a simple, non-invasive and real-time plasma monitoring tool. In OES, the trend of a few sensitive wavelengths is traced. However, in case of small-open area etch endpoint detection (ex. contact etch), it is at the boundary of the detection limit because of weak signal intensities of reaction reactants and products. Furthemore, the various materials covering the wafer such as photoresist (PR), dielectric materials, and metals make the analysis of OES signals complicated. In this study, full spectra of optical emission signals were collected and the data were analyzed by a data-mining approach, modified K-means cluster analysis. The K-means cluster analysis is modified suitably to analyze a thousand of wavelength variables from OES. This technique can improve the sensitivity of EPD for small area oxide layer etching processes: about 1.0 % oxide area. This technique is expected to be applied to various plasma monitoring applications including fault detections as well as EPD.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.118-119
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• 2009

This paper presents the feature profile evolution silicon deep trench etching, which is very crucial for the commercial wafer process application. The silicon deep trenches were etched with the SF6 gas & Hbr gas based process recipe. The optimized silicon deep trench process resulted in vertical profiles (87o~90o) with loading effect of < 1%. The process recipes were developed for the silicon deep trench etching applications. This scheme provides vertically profiles without notching of top corner was observed. In this study, the production of SF6 gas based silicon deep trench etch process much more strongly than expected on the basis of Hbr gas trench process that have been investigated by scanning electron microscope (SEM). Based on the test results, it is concluded that the silicon deep trench etching shows the sufficient profile for practical MOS FET silicon deep trench technology process.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.10
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• pp.752-758
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• 2010

The etching characteristics of indium tin oxide (ITO) thin films in an $O_2/BCl_3/Ar$ plasma were investigated. The etch rate of ITO thin films increased with increasing $O_2$ content from 0 to 2 sccm in $BCl_3$/Ar plasma, whereas that of ITO decreased with increasing $O_2$ content from 2 sccm to 6 sccm in $BCl_3$/Ar plasma. The maximum etch rate of 65.9 nm/m in for the ITO thin films was obtained at 2 sccm $O_2$ addition. The etch conditions were the RF power of 500 W, the bias power of 200 W, the process pressure of 15 mTorr, and the substrate temperature of $40^{\circ}C$. The analysis of x-ray photo electron spectroscopy (XPS) was carried out to investigate the chemical reactions between the surfaces of ITO thin films and etch species.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.509-509
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• 2011

Superhydrophobic surfaces on alloyed steels were fabricated with a non-conventional method of plasma etching and subsequent water immersion procedure. High aspect ratio nanopatterns of nanoflake or nano-needle were created on the steels with various Cr content in its composition. With CF4 plasma treatment in radio-frequence chemical vapor deposition (r.-f. CVD) method, steel surfaces were etched and fluorinated by CF4 plasma, which induced the nanopattern evolution through the water immersion process. It was found that fluorine ion played a role as a catalyst to form nanopatterns in water elucidated with XPS and TEM analysis. The hierarchical patterns in micro- and nano scale leads to superhydrophobic properties on the surfaces by deposition of a hydrophobic coating with a-C:H:Si:O film deposited with a gas precursor of hexamethlydisiloxane (HMDSO) with its lower surface energy of 24.2 mN/m, similar to that of curticular wax covering lotus surfaces. Since this method is based on plasma dry etching & coating, precise patterning of surface texturing would be potential on steel or metal surfaces. Patterned hydrophobic steel surfaces were demonstrated by mimicking the Robinia pseudoacacia or acacia leaf, on which water was collected from the humid air using a patterned hydrophobicity on the steels. It is expected that this facile, non-toxic and fast technique would accelerate the large-scale production of superhydrophobic engineering materials with industrial applications.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.04a
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• pp.49-51
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• 2006

OLEOs was fabricated by PLD method. Wet etching process and plasma treatment of ITO on the glass were performed to extend the lifetime of the OLED and increase its brightness. The NPB, $Alq_3$, Li-Benzoate and AI layers on ITO pattern on the glass were deposited by PLO method, sequentially. When the etched ITO was treated by $O_2$ plasma with RF power of 50W, the best result was obtained. The lifetime of the OLED treated by $O_2$ plasma was extended from 3,770sec to 12,586sec compared to that without the plasma treatment.

• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.96-98
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• 2006

A new ex-situ model to diagnose a plasma processing equipment was presented. The model was constructed by combining wavelet, scanning electron microscope, ex-situ measurement of etching profile, and neural network. The diagnosis technique was applied to a tungsten etching process, conducted in a $SF_6$ helicon plasma. The wavelet was used to characterize detailed variations of plasma-etched surface. The diagnosis model was constructed with the vertical wavelet component. For comparison, a conventional model was built by using the estimated profile data. Compared to the conventional model, the wavelet-based model, demonstrated a much improved diagnosis.

• Transactions on Electrical and Electronic Materials
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• v.11 no.4
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• pp.166-169
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• 2010

In this study, we changed the etch parameters (gas mixing ratio, radio frequency [RF] power, direct current [DC]-bias voltage, and process pressure) and then monitored the effect on the $HfAlO_3$ thin film etch rate and the selectivity with $SiO_2$. A maximum etch rate of 108.7 nm/min was obtained in $Cl_2$ (3 sccm)/$BCl_3$ (4 sccm)/Ar (16 sccm) plasma. The etch selectivity of $HfAlO_3$ to $SiO_2$ reached 1.11. As the RF power and the DC-bias voltage increased, the etch rate of the $HfAlO_3$ thin film increased. As the process pressure increased, the etch rate of the $HfAlO_3$ thin films increased. The chemical state of the etched surfaces was investigated with X-ray photoelectron spectroscopy. According to the results, the etching of $HfAlO_3$ thin film follows the ion-assisted chemical etching.