• Transactions on Electrical and Electronic Materials
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• 제14권2호
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• pp.71-77
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• 2013

Advanced semiconductor manufacturing technology requires methods to maximize tool efficiency and improve product quality by reducing process variability. Real-time plasma process monitoring and diagnosis have become crucial for fault detection and classification (FDC) and advanced process control (APC). Additional sensors may increase the accuracy of detection of process anomalies, and optical monitoring methods are non-invasive. In this paper, we propose the use of a chromatic data acquisition system for real-time in-situ plasma process monitoring called the Plasma Eyes Chromatic System (PECS). The proposed system was initially tested in a six-inch research tool, and it was then further evaluated for its potential to detect process anomalies in an eight-inch production tool for etching blanket oxide films. Chromatic representation of the PECS output shows a clear correlation with small changes in process parameters, such as RF power, pressure, and gas flow. We also present how the PECS may be adapted as an in-situ plasma arc detector. The proposed system can provide useful indications of a faulty process in a timely and non-invasive manner for successful run-to-run (R2R) control and FDC.

• 인터넷정보학회논문지
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• 제16권6호
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• pp.31-37
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• 2015

최근 사물인터넷 발달로 인하여 센서에서 발생되는 데이터가 폭증하고 있다. 이러한 패러다임의 변화로 즉각 행동이 요구되는 여러 산업현장에서 실시간으로 발생되는 데이터들의 분석이 필요하게 되었으며, 실시간 시각화 분석이 대두되고 있다. 그러나 기존 시각화 시스템은 데이터를 저장 후에 시각화를 하기 때문에 서버의 응답시간이 실시간에 준하는 ms수준의 처리를 보장하지 못하며, 처리할 자원을 보유하고 있지 않아 주요 자원이 될 데이터를 폐기하는 문제가 발생한다. 따라서 본 논문에서는 가드닝 환경에서 IoT 센싱 정보를 활용하여 실시간 시각화 알고리즘을 적용한 스마트가드닝 시스템을 설계 및 구현하였다. 제안 시스템의 성능 평가를 위하여 서버의 응답시간을 측정하였고, 테스트 결과 제안하는 실시간 시각화 알고리즘의 응답 속도는 실시간에 준하는 ms수준의 처리를 보장함을 확인하였다.

• Transactions on Control, Automation and Systems Engineering
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• 제2권1호
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• pp.40-46
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• 2000

In this paper, a transient identification based on a Hidden Markov Model (HMM) has been suggested and evaluated experimentally for the classification of transients in the dynamic process. The transient can be identified by its unique time dependent patterns related to the principal variables. The HMM, a double stochastic process, can be applied to transient identification which is a spatial and temporal classification problem under a statistical pattern recognition framework. The HMM is created for each transient from a set of training data by the maximum-likelihood estimation method. The transient identification is determined by calculating which model has the highest probability for the given test data. Several experimental tests have been performed with normalization methods, clustering algorithms, and a number of states in HMM. Several experimental tests have been performed including superimposing random noise, adding systematic error, and untrained transients. The proposed real-time transient identification system has many advantages, however, there are still a lot of problems that should be solved to apply to a real dynamic process. Further efforts are being made to improve the system performance and robustness to demonstrate reliability and accuracy to the required level.

• 소성∙가공
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• 제17권7호
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• pp.496-500
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• 2008

Plastics is commonly used in consumer electronics because of it is high strength per unit mass and good productivity. But plastic parts are usually distorted after injection molding due to the residual stress after filling, packing, cooling process, and etc. And plastic material is to be deteriorated according to various temperature conditions and operating time, which can be characterized by stress relaxation and creep. The viscoelastic behavior of plastic materials in time domain can be expressed by the Prony series of the commercial code, ABAQUS. In the paper, the process to predict the post deformation under cyclic thermal loadings was suggested. The process was applied to the real panel, and the deformation predicted by the analysis was compared with that of real test, which showed the possibility of applying the suggested process to predict the post deformation of plastic product under thermal loadings.

• 한국지능정보시스템학회:학술대회논문집
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• 한국지능정보시스템학회 1999년도 춘계공동학술대회-지식경영과 지식공학
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• pp.353-359
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• 1999

We present a matrix-based inference alorithm suitable for electronic commerce applications. For this purpose, an Extended AND-OR Graph (EAOG) was developed with the intention that fast inference process is enabled within the electronic commerce situations. The proposed EAOG inference mechanism has the following three characteristics. 1. Real-time inference: The EAOG inference mechanism is suitable for the real-time inference because its computational mechanism is based on matric computation.2. Matrix operation: All the subjective knowledge is delineated in a matrix form, so that inference process can proceed based on the matrix operation which is computationally efficient.3. Bi-directional inference: Traditional inference method of expert systems is based on either forward chaining or backward chaining which is mutually exclusive in terms of logical process and exclusive in terms of logical process and computational efficiency. However, the proposed EAOG inference mechanism is generically bi-directional without loss of both speed and efficiency. We have proved the validity of our approach with several propositions and an illustrative EC example.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 추계학술대회
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• pp.30-35
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• 2003

Recently, with the rapid growth of information technology, many studies have been performed to implement web-based manufacturing system. Such technologies are expected to meet the need of many manufacturing industries those want to adopt E-manufacturing system for the construction of globalization, agility, digitalization to cope with the rapid changing market requirements. In this research, areal-time web-based machine tool and machining process monitoring system is developed as a first step fur implementing I-manufacturing system. In this system, main spindle motor current and feed current are measured using hall sensors. And the relationship between the cutting force and the spindle motor RMS current at various spindle rotational speed is obtained. Also, a rule-based expert system is developed in order to monitor the machining process effectively. Finally, developed system is applied to real machining process to verify the effectiveness.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 1995년도 특별강연 및 춘계학술발표 개요집
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• pp.118-122
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• 1995

The hydraulic or pneumatic valve spools become essential as the important components on the production of automatic hydraulic or pneumatic machinaries as mechanical industry is developed rapidly. The machining precision is asked for manufacturing the valve spools. They could be unstable in the quality by the conventional arc welding and they have a lot of technical problems in manufacturing because their shapes are generally small. By the Precision casting process such as lost wax process, the production cost will be increased. But by the friction welding technique, they will be able to be made without such problems. Furthermore, there is a few study on friction welding of such hydraulic valve spool steels and in-process real-time weld quality evaluation technique by acoustic emission. So that, the final purpose of this study is 1) the development of design and manufacturing technique of hydraulic or pneumatic valve spool by optimizing of friction welding, and 2) the development of in-process real-time weld quality evaluation technique by acoustic emission.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1693-1696
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• 2004

Synchrotron X-ray micro-imaging technique was employed to monitor non-invasively the refilling process of water inside the xylem vessels in bamboo leaves. The consecutive phase-contrast X-ray images clearly show both plant anatomy and the transport of water inside the xylem vessels. Traces of water-rise, vapor bubbles and variations of contact angle between the water front and the xylem wall were measured in real time. During the refilling process, air bubbles are removed when the rising water front halts at a vessel end for a while. Subsequently, it starts rising again at a higher velocity than the normal refilling speed. Repeated cavitation seems to deteriorate the refilling ability in xylem vessels. In dark environment, the water refilling process in xylem vessels is facilitated more effectively than in bright illuminated conditions. Finally, X-ray micro-imaging was famed to be a powerful, high resolution, real time imaging tool to investigate the water refilling process in xylem vessels.

• 반도체디스플레이기술학회지
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• 제19권2호
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• pp.16-21
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• 2020

How accurately reproducible energy is delivered to the wafer in the process of making thin films using PE-CVD (Plasma enhanced chemical vapor deposition) during the semiconductor process. This is the most important technique, and most of the reaction on the wafer surface is made by thermal energy. In this study, we studied the method of monitoring the change of thermal energy transferred to the wafer surface by monitoring the temperature change according to the change of the thin film formed on the showerhead facing the wafer. Through this research, we could confirm the monitoring of wafer thin-film which is changed due to abnormal operation and accumulation of equipment, and we can expect improvement of semiconductor quality and yield through process reproducibility and equipment status by real-time monitoring of problem of deposition process equipment performance.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 춘계학술대회 논문집
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• pp.288-292
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• 2008

Plastics is commonly used in consumer electronics because of it is high strength per unit mass and good productivity. But plastic parts are usually distorted after injection molding due to the residual stress after filling, packing, cooling process, and etc. And plastic material is to be deteriorated according to various temperature conditions and operating time, which can be characterized by stress relaxation and creep. The viscoelastic behaviour of plastic materials in time domain can be expressed by the Prony series of the commercial code, ABAQUS. In the paper, the process to predict the post deformation under cyclic thermal loadings was suggested. The process was applied to the real panel, and the deformation predicted by the analysis was compared with that of real test, which showed the possibility of applying the suggested process to predict the post deformation of plastic product under thermal loadings.