• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1500-1503
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• 1997

In this paper a multiple channel EPD controller is developed which enables us to detect endpoints simultaneously in the plasma etching process operated in multiple etching chambers and its performance characteristic are investigated. for the accurate detectiion of endpoint the developed EDP controller was able to implement endpoint detectiions by integrating the existing EPD controllers with the techiques of artificial intellignet, to enhance its performance. The performance of the developed EPD controller was carried out by repeated experiments of endpoint detection in the acrual production line of semiconductor manufacturing. It's utility for endpoint detectiion was accurately evaluated in various etching process. The control capability of multiple etching chambers enhances its application compared with the existing one, and also increases the user utility os that the efficiency of operation was improved.

• 반도체디스플레이기술학회지
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• 제21권2호
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• pp.45-50
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• 2022

The etching with high selectivity of silicon dioxide over silicon nitride is essential in semiconductor fabrication, and gas phase etch (GPE) can increase the competitiveness of the selective dielectric etch. In this work, GPE of plasma enhanced chemical vapor deposited SiO₂ was performed, and the effects of process parameters, such as temperature, partial pressure ratio, and gas supply cycle, are investigated in terms of etch rate and within wafer uniformity. Employing multiple regression analysis, the importance of each parameter elements is analyzed.

• 한국산업융합학회 논문집
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• 제26권4_1호
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• pp.517-527
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• 2023

Many techniques have been proposed and investigated for microlens array manufacturing in three-dimensional (3D) structures. We present fabricating a microlens array using selective laser etching and a CO₂ laser. The femtosecond laser was employed to produce multiple micro-cracks that comprise the predesigned 3D structure. Subsequently, the wet etching process with a KOH solution was used to produce the primary microlens array structures. To polish the nonoptical surface to the optical surface, we performed reflow postprocessing using a CO₂ laser. We confirmed that the micro lens array can be manufactured in three primary shapes (cone, pyramid and hemisphere). Compared to our previous study, the processing time required for laser processing was reduced from approximately 1 hour to less than 30 seconds using the proposed processing method. Therefore, micro lens arrays can be manufactured using our processing method and can be applied to mass productionon large surface areas.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권5호
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• pp.396-401
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• 1999

In this study, $Ar^+$ ion laser etching process of single/poly-crystalline Si with $CCl_2F_2$ gas is investigated for MEMS applications. In general, laser direct etching process is useful in microelectronic process, fabrication of micro sensors and actuators, rapid prototyping, and complementary processing because of the advantages of 3D micromachining, local etching/deposition process, and maskless process with high resolution. In this study, a pyrolytic method, in which $CCl_2F_2$ gasetches molten Si by the focused laser, was used. In order to analyze the temperature profile of Si by the focused laser, the 3D heat conduction equation was analytically solved. In order to investigate the process parameters dependence of etching characteristics, laser power, $CCl_2F_2$ gas pressure, and scanning speed were varied and the experimental results were observed by SEM. The aspect ratio was measured in multiple scanning and the simple 3D structure was fabricated. In addition, the etching characteristics of $6\mum$ thick poly-crystalline Si on the insulator was investigated to obtain flat bottom and vertical side wall for MEMS applications.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 C
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• pp.1001-1003
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• 1998

In this paper, $Ar^+$ ion laser etching process of single/poly crystalline silicon with $CCl_{2}F_{2}$ gas is studied for MEMS applications. To investigate the effects of process parameters, laser power, gas pressure, scanning speed were varied and multiple scanning was carried out to obtain high aspect ratio. In addition, scanning width was varied to observe the trench profile etched in repeating scanning cycle. From the etching of $2.6{\mu}m$ thick polycrystalline Si deposited on insulator, trench with flat bottom and vertical side wall was obtained and it is possible to apply this results for MEMS applications.

• Journal of the Optical Society of Korea
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• 제18권3호
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• pp.283-287
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• 2014

Square lattice nano-hole arrays with diameters and periodicities of 200 and 500 nm, respectively, are fabricated on InGaN/GaN blue light emitting diodes (LEDs) using electron-beam lithography and inductively coupled plasma reactive ion etching processes. Cathodoluminescence (CL) investigations show that light emission intensity from the LEDs with the nano-hole arrays is enhanced compared to that from the planar sample. The CL intensity enhancement factor decreases when the nano-holes penetrate into the multiple quantum wells (MQWs) due to the plasma-induced damage and the residues. Wet chemical treatment using KOH solution is found to be an effective method for light extraction from the nano-patterned LEDs, especially, when the nano-holes penetrate into the MQWs. About 4-fold CL intensity enhancement factor is achieved by the KOH treatments after the dry etching for the sample with a 250-nm deep nano-hole array.

• Transactions on Electrical and Electronic Materials
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• 제6권6호
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• pp.262-271
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• 2005

In order to achieve timely and accurate fault detection of plasma etching process, neural network based time series modeling has been applied to reactive ion etching (RIE) using two different in-situ plasma-monitoring sensors called optical emission spectroscopy (OES) and residual gas analyzer (RGA). Four different subsystems of RIE (such as RF power, chamber pressure, and two gas flows) were considered as potential sources of fault, and multiple degrees of faults were tested. OES and RGA data were simultaneously collected while the etching of benzocyclobutene (BCB) in a $SF_6/O_2$ plasma was taking place. To simulate established TSNNs as incipient fault detectors, each TSNN was trained to learn the parameters at t, t+T, ... , and t+4T. This prediction scheme could effectively compensate run-time-delay (RTD) caused by data preprocessing and computation. Satisfying results are presented in this paper, and it turned out that OES is more sensitive to RF power and RGA is to chamber pressure and gas flows. Therefore, the combination of these two sensors is recommended for better fault detection, and they show a potential to the applications of not only incipient fault detection but also incipient real-time diagnosis.

• 전기전자학회논문지
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• 제23권2호
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• pp.534-537
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• 2019

광학적 손실은 태양전지 표면에 조사되는 빛이 태양전지 내부로 흡수되지 않고 표면에서 반사되어 발생하는 손실이다. 이러한 빛의 반사로 인한 광학적 손실을 줄이고 태양전지의 변환 효율을 높이기 위한 연구가 활발하게 진행되고 있다. 본 논문에서는 유리기판 표면을 습식 식각을 사용하여 표면을 거칠게 형성해 식각된 표면의 구조적 특성을 평가하였고, 분광기를 통해 식각된 표면의 광학적 특성을 분석하였다. 식각을 통해 형성되는 분화구 모양의 거친 표면은 입사되는 빛을 태양전지 내부로 재흡수하여 빛의 반사를 줄어들었고, 이에 따라 투과되는 빛이 증가하였음을 확인하였다.

• 대한치과교정학회지
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• 제23권1호
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• pp.75-88
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• 1993

Recent reports indicate that shorter etching times than 60 seconds can be adopted without affecting the bond strength and clinical disadvantages. The purpose of this in vitro study was to compare the shear bone strength and to measure depth of etch at different etching time length. One hundred and eight extracted bovine lower central incisors were embedded each in a tooth cup with cold-cure acrylic resin. The facial surfaces of the teeth were ground wet with 600-, 800-, 1000-, and 1200-grit Sic papers, and finally polished with a water slurry of extrafine silicon carbide powder, washed with tap water, and dried with hot air. Nine groups of nine prepared teeth were etched with a commercial($38\%$ phosphoric acid solution) for 0, 5, 10, 15, 20, 30, 60, 90, and 120 seconds, respectively, rinsed with tap water, and dried with hot air. One conditioned teeth from every group was selected randomly for the scanning electron microscopic examination, and the remaining eight teeth of the groups were used for measuring the push shear bond strength after bonding brackets and immensing them in the $36.5^{\circ}C$ water for 24 hours. Another nine groups of three teeth were used for measuring the depth of etch and surface roughness with a surface profilometer. after pieces of adhesive tape of 3mm inner diameter positioned on the ground enamel surfaces, and etched with the above mentioned. The data obtained form the above expeiments were analysed statistically with one way ANOVA and Dunkan's multiple range test with the $95\%$ confidence level. The results and conclusion of the study were as follows; 1. The results of shear bond strength for the given experimental etching times were not statistically different, but showed the tendency of decreasing shear bone strength after over 60 seconds etching times. 2. On the scanning election microscopic examination, it was observed that the morphological patterns of etched enamel surface for 5 to 20 seconds were similar and consitent, and those for 30 to 120 seconds showed increasing over-etched patterns depending on the length of etching times. 3. The depth of etch was increased almost proportionally by the length of etching times, but it was not associated with the shear bond strength. 4. The surface roughness increased depending on the length of etching times, but it was not associated with the shear bond strength. 5. This experiment indicated that proper etching time with $38\%$ phosphoric acid solution is in the range of 5 to 30 seconds.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제36회 동계학술대회 초록집
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• pp.262.2-262.2
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• 2009