• Transactions on Electrical and Electronic Materials
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• v.1 no.3
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• pp.14-17
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• 2000

Giga bit dynamic random access memory(DRAM) requires the capacitor of high dielectric films. Some metal oxides films have been proposed as the dielectric material . And Pt is one of the most promising electrode materials. However very little has been done in developing the etching technologoy Pt film. Therefore, it is the first priority to develop the technology for plasma etching of Pt film. In this study, the dry etching of Pt film was investigated in Inductively Coupled Plasma(ICP) etching system with Cl$_2$/Ar and HBr/Cl$_2$/Ar gas mixing. X-ray photoelectron spectroscopy (XPS) was used in analysis of sidewall residues for the understanding of etching mechanism. We found the etch residues on the pattern sidewall is mainly Pt-Pt, Pt-Cl and Pt-Br compounds, Etch profile was observed by Scanning Electron Spectroscopy(SEM) . The etch rate of Pt film at 10%, Cl$_2$/90% Ar gas mixing ration was higher than at 100%. Ar. Addition of HBr to Cl$_2$/Ar as an etching gas led to generally higher selectivity to SiO$_2$. And the etch residues were reduced at 5% HBr/5% Cl$_2$/90% Ar gas mixing ration. These pages provide you with an examples of the layout and style which we wish you to adopt during the preparation of your paper, Make the width of abstract to be 14cm.

• Journal of the Semiconductor & Display Technology
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• v.18 no.4
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• pp.35-39
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• 2019

Effect of Ge₂Sb₂Te₅ (GST) chalcogen composition on plasma induced damage was investigated by using Ar ions and F radicals. Experiments were carried out with three different modes; the physical etching, the chemical etching, and the ion-enhanced chemical etching mode. For the physical etching by Ar ions, the sputtering yield was obtained according to ion bombarding energy and there was no change in GST composition ratio. In the plasma mode, the lowest etch rate was measured at the same applied power and there was also no plasma induced damage. In the ion-enhanced chemical etching conditions irradiated with high energy ions and F halogen radicals, the GST composition ratio was changed according to the density of F radicals, resulting in higher roughness of the etched surface. The change of GST composition ratio in halogen plasma is caused by the volatility difference of GST-halogen compounds with high energy ions over than the activation energy of surface reactions.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.4 s.193
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• pp.147-152
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• 2007

UV laser ablation of polyimide is a combination of photochemical and photothermal mechanism. Photochemical mechanism is that molecular bonds are broken by photon energy and photothermal is evaporation and melt expulsion. When the laser processing, the etching depth needs to be calculated for prediction of processing result. In this paper, in order to predict the laser etching depth of polyimide by UV laser with the wavelength of 355nm, the theoretical model which includes both the photothermal and the photochemical effect was introduced. The model parameters were obtained by comparing with experimental results. The 3rd harmonic $Nd:YVO_4$ laser system was used in the experiment. From these experimental and theoretical results, the laser ablation of a polyimide was verified to achieve the highest quality microstructure.

• Journal of information and communication convergence engineering
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• v.10 no.3
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• pp.295-299
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• 2012

Defect generation during organic bottom anti-reflective coating (BARC) in the photo lithography process is closely related to humidity control in the BARC coating unit. Defects are related to the water component due to the humidity and act as a blocking material for the etching process, resulting in an extreme pattern bridging in the subsequent BARC etching process of the poly etch step. In this paper, the lower limit for the humidity that should be stringently controlled for to prevent defect generation during BARC coating is proposed. Various images of defects are inspected using various inspection tools utilizing optical and electron beams. The mechanism for defect generation only in the specific BARC coating step is analyzed and explained. The BARC defect-induced gate pattern bridging mechanism in the lithography process is also well explained in this paper.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2001.11a
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• pp.161-164
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• 2001

• 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.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.24 no.5
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• pp.196-201
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• 2014

We investigated defects and surface polarity in AlN and GaN by using wet chemical etching. Therefore, the effectiveness and reliability of estimating the single crystals by defect selective etching in NaOH/KOH eutectic alloy have been successfully demonstrated. High-quality AlN and GaN single crystals were etched in molten NaOH/KOH eutectic alloy. The etching characteristics and surface morphologies were carried out by scanning electron microscope (SEM) and atomic force microscope (AFM). The etch rates of AlN and GaN surface were calculated by etching depth as a function of etching time. As a result, two-types of etch pits with different sizes were revealed on AlN and GaN surface, respectively. Etching produced hexagonal pits on the metal-face (Al, Ga) (0001) plane, while hexagonal hillocks formed on the N-face. On etching rate calibration, it was found that N-face had approximately 109 and 15 times higher etch rate than the metal-face of AlN and GaN, respectively. The size of etch pits increased with an increase of the etching time and they tend to merge together with a neighbouring etch pits. Also, the chemical mechanism of each etching process was discussed. It was found that hydroxide ion ($OH^-$) and the dangling bond of nitrogen play an important role in the selective etching of the metal-face and N-face.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.418-418
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• 2008

The electrochemical etching of silicon in HF-based solutions is known to form various types of porous structures. Porous structures are generally classified into three categories according to pore sizes: micropore (below 2 nm in size), mesopore (2 ~ 50 nm), and macropore (above 50 nm). Recently, the formation of macropores has attracted increasing interest because of their promising characteristics for an wide scope of applications such as microelectromechanical systems (MEMS), chemical sensors, biotechnology, photonic crystals, and photovoltaic application. One of the promising applications of macropores is in the field of MEMS. Anisotropic etching is essential step for fabrication of MEMS. Conventional wet etching has advantages such as low processing cost and high throughput, but it is unsuitable to fabricate high-aspect-ratio structures with vertical sidewalls due to its inherent etching characteristics along certain crystal orientations. Reactive ion dry etching is another technique of anisotropic etching. This has excellent ability to fabricate high-aspect-ratio structures with vertical sidewalls and high accuracy. However, its high processing cost is one of the bottlenecks for widely successful commercialization of MEMS. In contrast, by using electrochemical etching method together with pre-patterning by lithographic step, regular macropore arrays with very high-aspect-ratio up to 250 can be obtained. The formed macropores have very smooth surface and side, unlike deep reactive ion etching where surfaces are damaged and wavy. Especially, to make vertical microwire or nanowire arrays (aspect ratio = over 1:100) on silicon wafer with top-down photolithography, it is very difficult to fabricate them with conventional dry etching. The electrochemical etching is the most proper candidate to do it. The pillar structures are demonstrated for n-type silicon and the formation mechanism is well explained, while such a experimental results are few for p-type silicon. In this report, In order to understand the roles played by the kinds of etching solution and mask patterns in the formation of microwire arrays, we have undertaken a systematic study of the solvent effects in mixtures of HF, dimethyl sulfoxide (DMSO), iso-propanol, and mixtures of HF with water on the structure formation on monocrystalline p-type silicon with a resistivity with 10 ~ 20 $\Omega{\cdot}cm$. The different morphological results are presented according to mask patterns and etching solutions.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.390-390
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• 2012

Information technology industries has grown rapidly and demanded alternative memories for the next generation. The most popular random access memory, dynamic random-access memory (DRAM), has many advantages as a memory, but it could not meet the demands from the current of developed industries. One of highlighted alternative memories is magnetic random-access memory (MRAM). It has many advantages like low power consumption, huge storage, high operating speed, and non-volatile properties. MRAM consists of magnetic-tunnel-junction (MTJ) stack which is a key part of it and has various magnetic thin films like CoFeB, FePt, IrMn, and so on. Each magnetic thin film is difficult to be etched without any damages and react with chemical species in plasma. For improving the etching process, a high density plasma etching process was employed. Moreover, the previous etching gases were highly corrosive and dangerous. Therefore, the safety etching gases are needed to be developed. In this research, the etch characteristics of CoFeB magnetic thin films were studied by using an inductively coupled plasma reactive ion etching in $CH_4/O_2/Ar$ gas mixes. TiN thin films were used as a hardmask on CoFeB thin films. The concentrations of $O_2$ in $CH_4/O_2/Ar$ gas mix were varied, and then, the rf coil power, gas pressure, and dc-bias voltage. The etch rates and the selectivity were obtained by a surface profiler and the etch profiles were observed by a field emission scanning electron microscopy. X-ray photoelectron spectroscopy was employed to reveal the etch mechanism.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.385-385
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• 2010

In this work, we have investigated the etching characteristics of $TiO_2$ and selectivity of $TiO_2$ over $SiO_2$ thin films as resistance in ReRAM using the inductively coupled plasma. The etch rate and selectivity were measured by varying the $BCl_3$ addition into Ar plasma. The maximum etchrate was obtained at 110.1nm/min at $BCl_3$/Ar=5sccm/10sccm, 500W for RFpower, -100v for DC-bias voltage, and 2Pa for the process pressure. The etched $TiO_2$ surface was investigated with X-ray photo electron spectroscopy. We explained the etching mechanism in two etch mechanisms, physiclas puttering and chemical reaction.