Papers by Keyword: Electrochemical Etching

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Authors: P.S. Pa
Abstract: The low yield rate in display panel production that results from imperfect Indium Tin Oxide layer deposition is well known. In this experiment a 6th Generation TFT-LCD is used to investigate an ultra-precise method for the removal of Indium Tin Oxide (ITO) thin film microstructure from defective display panels. The complete removal of the ITO layer makes it possible to put these panels back into the production line for reuse with a considerable reduction of both waste and production cost. This process, which involves the removal of ITO layer substructure by means of an electro-chemical etching process, is of major interest to the optoelectronics semiconductor industry. The ITO film can be removed completely by a proper combination of feed rate and electric power. In this electro machining process a high current flow and high feed rate of the display (color filter) achieves complete and efficient removal of the ITO layer. A large diameter cathode virtual rotation circle also corresponds to a higher removal rate. A small cathode end radius effectively improves dregs discharge and is an advantage when associated with a high workpiece feed rate. This precision reuse process for the recycling of defective display screen color filters is presented as an effective tool for use in the screen manufacturing process. The defective Indium Tin Oxide thin-film can be removed easily and cleanly in a short time.
Authors: Chi Yuan Lee, Shuo Jen Lee, Ching Liang Dai, Chih Wei Chuang
Abstract: This investigation utilizes porous silicon as the gas diffusion layer (GDL) in a micro fuel cell. Pt catalyst is deposited on the surface of, and inside the porous silicon, to improve the performance of a fuel cell, and the Pt metal that remains on the rib is used to form a micro thermal sensor in a single lithographic process. Porous silicon with Pt catalyst replaces traditional GDL, and the relationships between porosity and pore diameter, and the performance of the fuel cell are discussed. In this work, electrochemical etching technology is employed to form porous silicon to replace the gas diffusion layer of a fuel cell. This work focuses on porous silicon with dimensions of tens of micrometers. Porous silicon was applied to the gas diffusion layer of a micro fuel cell. Boron-doped 20 '-cm n-type (100)-oriented doubly polished silicon wafer was used on both sides. The process is performed to etch a fuel channel on one side of a silicon wafer, and then electrochemical etching was adopted to form porous silicon on the other side to fabricate one silicon wafer that combines porous silicon with a fuel channel on a silicon wafer to minimize a fuel cell. The principles on which the method is based, the details of fabrication flows, the set-up and the experimental results are all presented.
Authors: Jia Chuan Lin, Meng Kai Hsu, Hsi Ting Hou, Jia Chi Pan
Abstract: In this work, a combined process for simultaneously manufacturing nanoporous silicon (NPS) and its metallization was present. The key point is the utilization of adjust electrolyte of silver nitrate and the electroplating timing after the NPS etching process. The current-control mode was used to prepare NPS membrane and the obtained pore-size and pillar-depth were about 0.5 μm and 140 μm, respectively. For clarify the metallization quality of studied process, the semiconductor analyzer was utilized to measured current-voltage (IV) characteristic. Compared to NPS with conventional electroplating process, the contact properties of fabricated sample would be effectively improved by the proposed method. The obtained IV characteristic of sample with combined process shows a larger turn-on current about 277 times than other samples.
Authors: Ekaterina V. Astrova, Galya V. Fedulova, Yulia A. Zharova
Abstract: We propose electro-tunable composite structure of microcavity based on silicon 2D photonic crystal bar with a trench defect infiltrated with a liquid crystal. The device is fabricated by joint photo-electrochemical etching of deep macropores and trenches with subsequent trench opening from the substrate side. The optimized geometry and etching regime enables to minimize the lattice distortion introduced by trenches and to reduce roughness of the trench side walls. It was demonstrated that the structures with reach- through trenches and dead-end macropores are suitable for selective filling with a liquid crystal.
Authors: Hong Yu Wei, Zhong Ning Guo, Guan Wang
Abstract: Uniformity is an important index of the template electrochemical etching. Due to the uneven current distribution between the two electrodes, the etching depth of the workpiece center and edge are significantly different,and the deviation of which is up to 15% or more. In this study, the causes of edge effect is analyzed. A compensation method is proposed and proved by experiments.The results show that: this method is simple, and the uniformity can be reduced to about 3%. It is suitable for the processing of high uniformity requirements in microstructure machining.
Authors: C.-S. Chi, Y. Jeong, S.S. Kim, J.H. Lee, H.J. Oh
Abstract: The increase of capacitance on dielectric layer is associated with enlargement of etched surface area of electrodes for aluminum electrolytic capacitors. Etched tunnels extending along [100] directions are formed by crystallographic dissolution of aluminum in a chloride solution. This study has been focused primarily on the effects of addition of inhibitors to hydrochloric acid solution on the increase of the surface area by Electrochemical Impedance Spectroscopy (EIS). The addition of 3 % ethylene glycol was more effective for the enlargement of the surface area comparing with those of 1M sulfuric acid and no additive. And it was observed by TEM that the tunnels were grown straight and parallel to [100] directions.
Authors: Masashi Kato, Masaya Ichimura, Eisuke Arai, P. Ramasamy
Authors: Tamás Hurtony, Attila Bonyár, Péter Gordon
Abstract: In this study the possibility to apply electrochemical impedance spectroscopy as an alternative method for the characterisation of the intermetallic microstructures of Sn-3.5Ag lead free solder samples was investigated. The aim of the study is to compare the electrochemical impedance spectra of solder samples, reflowed with different heat profiles. A quenching technique was applied in order to solidify the solder samples in cylindrical crucibles. Differences in the microstructures of the solidified alloys were achieved by changing the temperature of the quenching media. The molded and cross sectioned specimens were observed using both optical microscopy and scanning electron microscopy (SEM) combined with energy dispersive spectroscopy (EDS). The microstructure of the ingots was revealed by selective electrochemical etching. The electrochemical impedance spectrum (EIS) was measured before and also after the selective etching process. The complex impedance spectra contain information regarding the characterized microstructure. Our aim is to determine quantitative parameters which are identical to the characteristics of the microstructure.
Authors: Y.T. Taurbayev, K.A. Gonchar, A.V. Zoteev, Victor Timoshenko, Z.Zh. Zhanabayev, V.E. Nikulin, T.I. Taurbayev
Abstract: Wafers of silicon and compound semiconductors are nanostructured by using electrochemical or chemical etching (stain etching) in etching cell with electrolyte kept by capillary forces. Atomic force microscopy, infrared spectroscopy and Raman scattering methods reveale nanoporous and nanocrystalline structure of the treated surfaces. The formed porous semiconductors demonstrate efficient photoluminescence, which is controlled by etching parameters, i.e. current density, electrolyte content, etc. These results indicate good prospects of the employed capillary-cell method for preparing nanostructured porous materials with desired structure and optical properties.
Authors: Hye Youn Lee, Masahiko Demura, Y. Xu, Dang Moon Wee, Toshiyuki Hirano
Abstract: Evolution of surface morphology in Ni(γ)/Ni3Al(γ´) two-phase foil of binary Ni-18 at.%Al was examined during the electrochemically selective etching in the electrolyte of distilled water including 1 wt.% (NH4)2SO4 and 1 wt.% citric acid. In the early stage (0.5 h), only the γ matrix was etched and the outmost γ´ particles were protected by a preexisting surface product. As the γ matrix was etched more, the side surfaces of the outmost γ´ particles and the γ´ particles that were located inside were exposed in the electrolyte. They were dissolved, and had a high density of fine dimples. However, the dissolution rate of the γ´ particles was slower than that of the γ matrix and thus the selective etching was retained in this stage. Finally, at 5h, more γ´ particles were exposed and the flat and smooth surfaces of the outmost γ´ particles were completely eliminated by the dissolution on the side surfaces. From these observations plus the saturation of the current density observed in the electrochemical test, we concluded that the change in the surface morphology was finished at this stage. Thus, the surface became more rough and irregular, which resulted from the original two-phase microstructure and the fine dimple structure by transpassivation.
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