• Restorative Dentistry and Endodontics
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• v.36 no.5
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• pp.385-396
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• 2011

Objectives: This study evaluated the effects of adhesion variables such as the priming concepts of canal wall and the curing modes of adhesives on the sealing ability of a resin-based root canal filling system. Materials and Methods: Apical microleakage of the Resilon-RealSeal systems filled with 3 different combinations of adhesion variables was compared with the conventional gutta-percha filling using a dye penetration method. Experimental groups were SEDC, Resilon (Resilon Research LLC) filling with self-etch RealSeal (SybronEndo) primer and dual-cure RealSeal sealer; NELC, Resilon filling with no etching, Scotchbond Multi-Purpose (3M ESPE) primer application and light-curing adhesive; and TELC, Resilon filling with Scotchbond Multi-Purpose primer and adhesive used under total etch / wet bonding and lightcure protocols. GPCS, gutta-percha filling with conventional AH26 plus sealer, was the control group. Results: The median longitudinal dye penetration length of TELC was significantly shorter than those of GPCS and SEDC (Kruskal-Wallis test, p < 0.05). In the cross-sectional microleakage scores, TELC showed significant differences from other groups at 2 to 5 mm from the apical foramen (Kruskal-Wallis test, p < 0.05). Conclusions: When a resin-based root canal filling material was used, compared to the self-etching primer and the dual-cure sealer, the total etch/wet-bonding with primer and light-curing of adhesive showed improved apical sealing and was highly recommended.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.4
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• pp.13-20
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• 2014

In this paper, the effects of a nonionic surfactant on the etch uniformity and the etch profile during the wet-etching process of high-purity aluminum were investigated for the fabrication of uniform micropattern arrays. To improve the surface roughness of a high-purity aluminum plate, a mechanical lapping process and an electrolytic polishing process were used. After electrolytic polishing process, the surface roughness, Ra, of the high-purity aluminum plate was improved from $1.25{\mu}m$ to $0.02{\mu}m$. A photoresist was used as an etching mask during the aluminum etching process, where the mixture of phosphoric acid, acetic acid, nitric acid, a nonionic surfactant and water was used as the aluminum etchant. Different amounts of the Triton X-100 nonionic surfactant were added to the aluminum etchant to investigate the effect of a nonionic surfactant during the wet-etching process of high-purity aluminum. The etch rate and the etch profile were measured by an optical interferometer and a scanning electron microscope.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.1
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• pp.40-44
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• 2022

Wet etching of α-Ga₂O₃ epitaxy film was performed using a 35 % hydrochloric (HCl) acid solution. As the temperature of the 35 % HCl solution increased, the α-Ga₂O₃ etch rate increased, and the etch rate of 119.6 nm/min was obtained at 75℃, the highest temperature examined in this work. The activation energy for etch reaction was determined to be 0.776 eV, and this suggests that the wet etching of α-Ga₂O₃ in the 35 % HCl solution was dominated by the reaction-limited mechanism. AFM analysis showed that the surface roughness of the etched surface increased as the temperature of the etchant solution increased.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.24 no.4
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• pp.135-139
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• 2014

The hydride vapor phase epitaxy (HVPE) grown GaN samples to precisely measure the surface characteristics was applied to a molten KOH/NaOH wet chemical etching. The etching rate by molten KOH/NaOH wet chemical etching method was slower than that by conventional etching methods, such as phosphoric and sulfuric acid etching, which may be due to the formation of insoluble coating layer. Therefore, the molten KOH/NaOH wet chemical etching is a better efficient method for the evaluation of etch pits density. The grown GaN single crystals were characterized by using X-ray diffraction (XRD) and X-ray rocking curve (XRC). The etching characteristics and surface morphologies were studied by scanning electron microscopy (SEM). From etching results, the optimum etching condition that the etch pits were well independently separated in space and clearly showed their shape, was $410^{\circ}C$ and 25 min. The etch pits density obtained by molten KOH/NaOH wet chemical etching under optimum etching condition was around $2.45{\times}10^6cm^{-2}$, which is commercially an available materials.

• Journal of the Korean Vacuum Society
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• v.7 no.3
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• pp.169-175
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• 1998

The plasma etching of polysilicon was performed with the HBr/$Cl_2/He-O_2$ gas mixture. The residual layers after photoresist strip were investigated using x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The etch residue was identified as silicon oxide deposited on the top of the patterned polysilicon. In order to clarify the formation mechanism of the etch residue, the effects of various gas mixtures such as $Cl_2/He-O_2$and HBr/$Cl_2$were investigated. We found that the etch residue is well formed in the presence of oxygen, suggesting that the etch residue is caused by the reaction of oxvgen and non-volatile silicon halide compounds. Wet cleaning and dry etch cleaning processes were applied to remove the polysilicon etch residue, which can affect the electrical characteristics and further device processes. XPS results show that the wet cleaning is suitable for the removal of the etch residue.

• Journal of Information Display
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• v.7 no.3
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• pp.1-4
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• 2006

2.22-inch qVGA $(240{\times}320)$ amorphous silicon thin film transistor liquid active matrix crystal display (a-Si TFT-AMLCD) panel has been successfully demonstrated employing a 2.5 um fine-patterning technology by a wet etch process. Higher resolution 2.22-inch qVGA LCD panel with an aperture ratio of 58% can be fabricated as the 2.5 um fine pattern formation technique is integrated with high thermal photo-resist (PR) development. In addition, a novel concept of unique a-Si TFT process architecture, which is advantageous in terms of reliability, was proposed in the fabrication of 2.22-inch qVGA LCD panel. Overall results show that the 2.5 um fine-patterning is a considerably significant technology to obtain higher aperture ratio for higher resolution a-Si TFT-LCD panel realization.

• Transactions of Materials Processing
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• v.13 no.3
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• pp.268-272
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• 2004

Transparent materials such as fused silica are widely utilized in optical and optoelectronics field because of its outstanding properties, such as transparency in a wide wavelength range, strong damage resistance for laser irradiation, and high thermal and chemical stability. In this study, we made a few micro patterns on the surface of fused silica plate using laser induced wet etching. KrF excimer laser was used as a light source. There were no burrs and micro cracks on the etched surface of fused silica and the flatness of the etched surface was fairly good. We investigated the influence of etchant upon the etch rate and quality in laser induced wet etching. Pyrene-acetone solution and toluene were used as etchant. In the side of etch rate, toluene solution was better than pyrene-acetone solution. But we made in wider range of energy density using pyrene-acetone solution. But pyrene-acetone solution gave us wider window of energy density for successful micro patterning.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1479-1482
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• 2009

Compared with tilt transfer wet station, vertical etching system has a variety of advantages that are 50% space savings, higher throughput, fairly good etch uniformity over an entire glass for thin film transistor application. The aim of the present work is to study on a vertical etching system to improve the process factors. The computational fluid dynamics analysis is used to demonstrate the change of the etch uniformity as a function of tilt angle of the glass substrate.

• Korean Journal of Materials Research
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• v.16 no.1
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• pp.63-67
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• 2006

The characteristics of the wet-etching of ZnO thin films were investigated using hydrochloric and phosphoric acid solutions as etchants. The etch rate of ZnO films, using highly diluted hydrochloric acid solutions at a concentration of 0.25% in deionized water, was determined to be about 120 nm/min, and linearly increased with increasing the acid concentration, resulting in $1.17{\mu}m/min$ when a 2% HCl solution was used. The surface of ZnO etched by an HCl solution, observed by scanning electron microscopy, showed a rough morphology with a high density of hexagonal pyramids or cones with sidewall angles of about ${\sim}45^{\circ}C$. Moreover, the sidewall angles of the masked area were similar to those of the pyramids on the surface. In comparison, the surface of ZnO etched by a phosphoric acid had a smooth surface morphology. The origin of this difference is from the very initial stage of etching, indicating that the etch-mechanism is different for each solution. Furthermore, when $H_3PO_4$ was added to the HCl aqueous solution, the morphology of the etched surface was greatly enhanced and the sidewall angle was also increased to about $65^{\circ}C$.

• Korean Journal of Materials Research
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• v.5 no.2
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• pp.208-214
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• 1995

In order to study on the penetrations of HF solution acording to the geometrical shrinkage of contact-hole pattern size, the wet etch characteristics for oxide in microchannel patterns was investigated. Microchannel patterns of LPCVD oxide surrounded by nitride film, with dimensions of 0.1~1$\mu\textrm{m}$ height and 0.1~20$\mu\textrm{m}$, width, were fabricated. And the etch rates of oxide in HF solution were observed. It was found that oxide etch rate for micro-channel patterns in HF was not affected by pattern sizes and initial aspect ratios up to $0.1 \times 0.1 \mu \textrm{m}^{2} size and 1.2$\mu\textrm{m}$ depth. Finally, it was concluded that there were no special limitations for penetrations of HF solution in wet processes according to the geometrical shrinkage of contact-hole pattern size.