• Journal of the Semiconductor & Display Technology
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• v.8 no.4
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• pp.1-5
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• 2009

This investigation is applied Taguchi method and the analysis of variance(ANOVA) to the reactive ion etching(RIE) characteristics of $SiO_2$ film coated on a wafer with Experimental Analysis and Optimization of $CF_4/O_2$ Plasma Etching Process mixture. Plans of experiments via nine experimental runs are based on the orthogonal arrays. A $L_9$ orthogonal array was selected with factors and three levels. The three factors included etching time, RF power, gas mixture ratio. The etching rate of the film were measured as a function of those factors. In this study, the etching thickness mean and uniformity of thickness of the RIE are adopted as the quality targets of the RIE etching process. The partial factorial design of the Taguchi method provides an economical and systematic method for determining the applicable process parameters. The RIE are found to be the most significant factors in both the thickness mean and the uniformity of thickness for a RIE etching process.

• Membrane Journal
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• v.23 no.1
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• pp.92-99
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• 2013

In this study the nanofiltration (NF) membrane treatment of a sulfuric acid waste solutions containing copper ion ($Cu^{+2}$) discharging from the etching processes of the printed circuit board (PCB) manufacturing industry has been studied for the recycling of acid etching solution. SelRO MPS-34 4040 NF membrane from Koch company was tested to obtain the basic NF data for recycling of etching solution and separation efficiency (total rejection) of copper ion. NF experiments were carried out with a dead-end membrane filtration laboratory system. The pure water flux was increased with the increasing storage time in sulfuric acid solution and lowering pH of acid solution because of the enhancement of NF membrane damage by sulfuric acid. The permeate flux of acid solution was decreased with the increasing copper ion concentration. Total rejection of copper ion was decreased with the increasing storage time in sulfuric acid solution and copper ion concentration, and lowering the pH of acid solution. The total rejection of copper ion was decreased from initial 37% to 15% minimum value.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1491-1493
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• 2000

Continuing improvement of microprocessor performance involves in the device size. This allow greater device speed, an increase in device packing density, and an increase in the number of functions that can reside on a single chip. However this has led to propagation delay, crosstalk noise, and power dissipation due to resistance-capacitance(RC) coupling become significant due to increased wiring capacitance, especially interline capacitance between the metal lines on the same metal level. So, MSSQ which has the permittivity between 2.5-3.2 is used to prevent from these problems. For pattering MSSQ(Methylsilsequioxane), we use RIE(Reactive Ion Etching) and MERIE(Magnetically enhanced Reactive Ion Etching) which could provide good anisotropic etching. In this study, we optimized the flow rate of $CF_{4}/O_2$ gas, RF power to obtain the best etching rate and roughness and also analyzed the etching result using $\alpha$-step profilemeter, SEM, infrared spectrum and AFM.

• Progress in Superconductivity
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• v.3 no.2
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• pp.168-171
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• 2002

We have demonstrated ramp-edge Josephson junctions using high temperature superconductors without depositing artificial barriers. We fabricated a surface barrier formed naturally during an ion beam etching process and the annealing under the oxygen atmosphere. The experimental results imply that the barrier natures such as the resistivity are varied by the annealing conditions and the ion milling conditions including the beam voltages. Thus, the ann eating and etching conditions should be optimized to obtain excellent junction properties. In optimizing the fabricating factors, the interface-controlled junctions showed resistively shunted junctions like current-voltage characteristics and an excellent uniformity. These junctions exhibited a spread ($1\sigma$) of $I_{c}$ is 10% fur chips containing 7 junctions at 50K.K.

• The Journal of Korean Academy of Prosthodontics
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• v.29 no.3
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• pp.75-86
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• 1991

Ion exchange strengthening is a chemical process whereby large alkali ions(such as potassium) are substituted for smaller ions(sodium) within the surfaces of glasses and ceramics, thereby reducing the thermal expansion coefficient of this surface region, and creating beneficial state of compressive stress within the near surface region. The purpose of this study was to determine the effects of ion exchange and etching treatments on the strength of some dental porcelains. Two feldspathic dental porcelains(Vitadur-N, G-Cera) were used in this study. A commercial ion exchange paste and etching gel containing 8% hydrofluoric acid were used for surface conditioning. Transverse strength was measured using a universal testing machine and the technique of EPMA(electron probe micro analysis) was used to access the potassium contents. The results were as follows: 1. Improvement in strength was only obtained by treating the surface placed in tension. 2. No changes in the dimensions of the treated specimens were detected when samples were measured with a micrometer. 3. There was significant increase in transverse strength of G-Cera IV group treated with etching and ion exchange, compared with G-Cera II group only treated with ion exchange. 4. From the results of EPMA test, increase in potassium contents was observed on the surface treated with ion exchange paste.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.65-65
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• 1999

Dry etching technique provides more easy controllability on the etch profile such as anisotropic etching than wet etching process and the results of lots of researches on the characterization of various plasmas or ion beams for semiconductor etching have been reported. Chlorine-based plasmas or chlorine ion beam have been often used to etch several semiconductor materials, in particular Si-based materials. We have studied the effect of He flow rate on the Si and SiO2 dry etching using chlorine-based plasma. Experiments were performed using reactive ion etching system. RF power was 300W. Cl2 gas flow rate was fixed at 58.6 sccm, and the He flow rate was varied from 0 to 120 sccm. Fig. 1 presents the etch depth of si layer versus the etching time at various He flow rate. In case of low He flow rate, the etch rate was measured to be negligible for both Si and SiO2. As the He flow increases over 30% of the total inlet gas flow, the plasma state becomes stable and the etch rate starts to increase. In high Ge flow rate (over 60%), the relation between the etch depth and the time was observed to be nearly linear. Fig. 2 presents the variation of the etch rate depending on the He flow rate. The etch rate increases linearly with He flow rate. The results of this preliminary study show that Cl2/He mixture plasma is good candidate for the controllable si dry etching.

• Journal of the Korean institute of surface engineering
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• v.34 no.5
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• pp.516-521
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• 2001

Dry etching of Si wafer and $SiO_2$ layers was performed using He/Cl$_2$ mixture plasma by diode-type reactive ion etcher (RIE) system. For Si etching, the Cl molecules react with the Si molecules on the surface and become chemically stable, indicating that the reactants need energetic ion bombardment. During the ion assisted desorption, energetic ions would damage the photoresist (PR) and produce the bad etch Si-profile. Moreover, we have examined the characteristics of the Cl-Si reaction system, and developed the new fabrication procedures with a $Cl_2$/He mixture for Si and $SiO_2$-etching. The developed novel fabrication procedure allows the RIE to be unexpensive and useful a Si deep etching system. Since the etch rate was proved to increase linearly with fHe and the selectivity of Si to $SiO_2$ etch rate was observed to be inversely proportional to fHe.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.331-332
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• 2007

Surface micromachined SiC devices have readily been fabricated from the polycrystalline (poly) 3C-SiC thin film which has an advantage of being deposited onto $SiO_2$ or $Si_3N_4$ as a sacrificial layer. Therefore, in this work, magnetron reactive ion etching process which can stably etch poly 3C-SiC thin films grown on $SiO_2$/Si substrate at a lower energy (70 W) with $CHF_3$ based gas mixtures has been studied. We have investigated the etching properties of the poly 3C-SiC thin film using PR/Al mask, according to $O_2$ flow rate, pressure, RF power, and electrode gap. The etched RMS (root mean square), etch rate, and etch profile of the poly 3C-SiC thin films were analyzed by SEM, AFM, and $\alpha$-step.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.7
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• pp.701-707
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• 2004

High aspect ratio silicon structure through deep silicon etching process have become indispensable for advanced MEMS applications. In this paper, we present the results of modified Bosch process to obtain anisotropic silicon structure with conventional Inductively Coupled Plasma (ICP) etcher instead of the expensive Bosch process systems. In modified Bosch process, etching step ($SFsub6$) / sidewall passivation ($Csub4Fsub8$) step time is much longer than commercialized Bosch scheme and process transition time is introduced between process steps to improve gas switching and RF power delivery efficiency. To optimize process parameters, etching ($SFsub6$) / sidewall passivation ($Csub4Fsub8$) time and ion energy effects on etching profile was investigated. Etch profile strongly depends on the period of etch / passivation and ion energy. Furthermore, substrate temperature during etching process was found to be an important parameter determining etching profile. Test structures with different pattern size have been etched for the comparison of the aspect ratio dependent etch rate and the formation of silicon grass. At optimized process condition, micropatterns etched with modified Bosch process showed nearly vertical sidewall and no silicon grass formation with etch rate of 1.2 ${\mu}{\textrm}{m}$/ min and the size of scallop of 250 nm.

• Journal of the Korean Vacuum Society
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• v.21 no.4
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• pp.199-204
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• 2012

$SF_6$ gas is widely used for dry etching process of semiconductor and display fabrication process. But $SF_6$ gas is considered for typical greenhouse gas for global warming. So it is necessary to research relating to $SF_6$ alternatives reducing greenhouse effect in semiconductor and display. $C_3F_6$ gas is one of the promising candidates for it. We studied about etch characteristics by performing Reactive Ion Etching process of dry etching and reduced gas element exhausted on etching process using absorbent Zeolite 5A. $Si_3N_4$ thin film was deposited to 500 nm with Plasma Enhanced Chemical Vapor Deposition and we performed Reactive Ion Etching process after patterning through photolithography process. It was observed that the etch rate and the etched surface of $Si_3N_4$ thin film with Scanning Electron Microscope pictures. And we measured and compared the exhausted gas before and after the absorbent using Gas Chromatograph-Mass Spectrophotometry.