• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1485-1488
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• 1997

The capacity of memory chip has increased vert quickly and 64MDRAM becomes main product in semiconductor manufacturing lines consists of many sequential processes, including etching process. although it needs direct sensing of wafer state for the accurae detching, it depends on indirect esnsing and sample test because of the complexity of the plasma etching. This equipment receives the inner light of etch chamber through the viewport and convets it to the voltage inetnsity. In this paper, EDP voltage signal has a new role to detect etching failure. First, we gathered data(EPD sigal, etching time and etchrate) and then analyzed the relationships between the signal variatin and the etch rate using two neural network modeling. These methods enable to predict whether ething state is good or not per wafer. For experiments, it is used High Density Inductive coupled Plasma(HDICP) ethcing equipment. Experiments and results proved to be abled to determine the etching state of wafer on-line and analyze the causes by modeling and EPD signal data.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.9 s.174
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• pp.60-68
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• 2005

To investigate the effects of beam focusing in the etching of polymers with short pulse Excimer lasers, a polymer etching model of SSB's is combined with a beam focusing model. Through the numerical simulation, it was found that in the high laser fluence region, SSB model considering both photochemical and thermal contribution is considered to be suitable to predict the etched hole shape than a simple photochemical etching model. The average temperature distribution into the substance obtained by assuming 1-D heat transfer is found to be fairly similar to the fluence distribution on the ablated surface. The experimental etching data fur polymers are used to give material properties for ablation model. The fitted etch depth curve gives a nice agreement with the experimental data.

• Textile Coloration and Finishing
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• v.8 no.2
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• pp.56-63
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• 1996

Low-temperature plasma treatment or sputter etching is of interest as one of the techniques to modify polymer surface. In this study, poly(ethylene terephthalate)(PET), nylon 6 and cotton fabrics dyed three black dyes were subjected to low-temperature argon plasma and also sputter etching. In relation to bathochromic effect, the surface characteristics of the treated fabrics and films were investigated by means of critical surface tension, SEM and ESCA measurement. The depth of shade of fabrics more increased by the sputter etching technique than argon plasma treatment. Many microcraters on the fiber surface formed by the sputter etching resulted in increase of surface area of the fiber and wettability, but the hydrophobic group was increased by the results of ESCA analysis. In particular the change in reflective index of the fibers was much more effective than the chemical composition of the fiber surface on increasing of the depth of shade.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04b
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• pp.112-116
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• 2000

This paper presents anisotropic ethcing characteristics of single-crystal silicon in tetramethylammonium hydroxide(TMAH):isopropyl alcohol(IPA) solutions containing pyrazine. With the addition of IPA to TMAH solutions, etching characteristics are exhibited that indicate an improvement in flatness on the etching front and a reduction in undercutting, but the etch rate on (100) silicon is decreased. The (100) silicon etch rate is improved by the addition of pyrazine. An etch rate on (100) silicon of $0.8\;{\mu}m/min$, which is faster by 13 % than a 20 wt.% solution of pure TMAH, is obtained using 20 wt.% TMAH:0.5 g/100 ml pyrazine solutions, but the etch rate on (100) silicon is decreased if more pyrazine is added. With the addition of pyrazine to a 25 wt.% TMAH solution, variations in flatness on the etching front were not observed and the undercutting ratio was reduced by 30 ~ 50 %.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.667-667
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• 2013

Optimizing morphology of the front surface with three dimensional structures (3D) in solar cell is essential element for not only effectivelight harvesting but also carrier collection and separation without the cost burden in process. We designed a three-dimensionally ordered front surface with wet chemical etching. Wet chemical etching is a proper way to have three dimensional structures. The method efficiently transmits the incident light at the front surface to a Si absorber and has competitive price in manufacturing when comparing with reactive ion etching (RIE) to have three dimensional structures. This indicates that optimized front surface with three dimensional structures by wet chemical etching will bring effective light management in solar cells.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.36 no.9
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• pp.636-639
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• 1987

In this study, we investigate the etching characteristics of a-Se75 Ge25 thin films. Etching properties are revealed as a function of obliqueness, temperature and concentraction of the etching solution. As the increase of obliqueness, selective etching effect increase rapidly by 35% at 80 obliqueness, and the etching rate increase the elevated temperature of the solution. The change of etching rate with obliqueness are related closely to the optical change due to the band gap illumination. We obtained clear pattern of 1.5um linewidth.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.3
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• pp.111-114
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• 2002

Using the plasma that we developed to generate a low-temperature plasma at atmospheric pressure, we have investigated the etching possibility of an air-exposed zinc oxide(ZnO) thin films. Hydrogen and methane radicals generated from the plasma were observed and their intensity was found to be dependent on the isomer of butyl acetate by an analysis with optical emission spectrosxopy. The etching ability of this plasma was evaluated by an emission intensity, etching time, rf power.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.866-869
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• 2001

In this study, (Ba,Sr)TiO$_3$(BST) thin films were etched with a magnetically enhanced inductively coupled plasma(MEICP). Etching characteristics of BST thin films including etch rate and selectivity were evaluated as a function of the etching parameters such as gas mixing ratio, rf power, dc bias voltage and chamber pressure. The maximum etch rate of the BST films was 1700 $\AA$/min at Ar(90)/CF$_4$(10), 600 W/350 V and 5 mTorr. The selectivity of BST to PR was 0.6, 0.7, respectively. To analyze the composition of surface residue remaining after the etching, samples etched with different CF$_4$/Ar gas mixing ratio were investigated with X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). From the results of XPS and SIMS, there are chemical reaction between Ba, Sr, Ti and C, F radicals during the etching and remained on the surface.

• Journal of the Semiconductor & Display Technology
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• v.2 no.3
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• pp.7-11
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• 2003

In this research, the etching characteristics of via contact and deep contact hole have been studied using multi-pole inductively coupled plasma(MICP) etching system. We investigated Plasma density of MICP source using the Langmuir probe and etching characteristics with RF frequency, wall temperature, chamber gap, and gas chemistry containing Carbon and Fluorine. As the etching time increases, formation of the polymer increases. To improve the polymer formation, we controlled the temperature of the reacting chamber, and we found that temperature of the chamber was very effective to decrease the polymer thickness. The deep contact etch profile and high selectivity(oxide to photoresist) have been achieved with the optimum mixed gas ratio containing C and F and the temperature control of the etching chamber.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.415-418
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• 1996

Etching Process, one of the most important process in semiconductor fabrication, has input control part of which components are pressure, gas flow, RF power and etc., and plasma gas which is complex and not exactly understood is used to etch wafer in etching chamber. So this process has not real-time feedback controller based on input-output relation, then it uses EPD(End Point Detection) signal to determine when to start or when to stop etching. Various type EPD controller control etching process using EPD signal obtained from optical intensity of etching chamber. In development EPD controller we concentrate on compensation of this signal intensity and setting the relative signal magnitude at first of etching. We compensate signal intensity using neural network learning method and set the relative signal magnitude using fuzzy inference method. Potential of this method which improves EPD system capability is proved by experiences.