• Journal of Korean Society of Industrial and Systems Engineering
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• v.33 no.3
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• pp.184-191
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• 2010

In the environment of 450mm wafers production known as the next-generation semiconductor production process, one of the most significant features is the full automation over the whole manufacturing processes involved. The full automation system for 450mm wafer production will minimize the human workers' involvement in the manufacturing process as much as possible. In addition, since the importance of an individual wafer processing increases noticeably, it is necessary to develop more robust scheduling systems in the whole manufacturing process than so ever. The scheduling systems for the next-generation semiconductor production processes also should be capable of monitoring individual wafers and collecting useful data on them in real time. Based on the information gathered from these processes, the system should finally have a real-time scheduling functions controlling whole the semiconductor manufacturing processes. In this study, preliminary investigations on the requirements and needed functions for constructing the real time scheduling system and transforming manufacturing environments for 300mm wafers to those of 400mm are conducted and through which the next generation semiconductor processes for efficient scheduling in a clustered production system architecture of the scheduler is proposed. Our scheduling architecture is composed of the modules for real-time scheduling, the clustered production type supporting, the optimal scheduling and so on. The specifications of modules to define the major required functions, capabilities, and the relationship between them are presented.

• Journal of the Semiconductor & Display Technology
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• v.15 no.3
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• pp.72-77
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• 2016

As the semiconductor production technology has gradually developed and intra-market competition has grown fiercer, the caliber of Si Wafer for semiconductor production has increased as well. And semiconductors have become integrated with higher density. Presently the Si Wafer caliber has reached up to 450 mm and relevant production technology has been advanced together. Electrostatic chuck is an important device utilized not only for the Wafer transport and fixation but also for the heat treatment process based on plasma. To effectively control the high calories generated by plasma, it employs a refrigerant-based cooling method. Amid the enlarging Si Wafers and semiconductor device integration, effective temperature control is essential. Therefore, uniformed temperature distribution in the electrostatic chuck is a key factor determining its performance. In this study, the form of refrigerant flow channel will be investigated for uniformed temperature distribution in electrostatic chuck.

• Proceedings of the KAIS Fall Conference
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• 2010.11b
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• pp.792-796
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• 2010

차세대 반도체 공정인 450mm 웨이퍼 생산 환경의 가장 큰 특징은 반도체 생산의 전 공정에 대한 완전 자동화이다. 이러한 완전 자동화는 작업자의 공정개입을 불가능하게 하고 개별 웨이퍼의 중요도를 크게 증가시키며 전체 반도체 생산 공정에 대한 견고한 디스패칭 시스템을 필요로 한다. 또한, 차세대 반도체 공정의 디스패칭 시스템은 개별 웨이퍼에 대한 실시간 모니터링과 데이터 수집이 가능해야 하며, 수집된 반도체 공정의 정보를 반영한 실시간 디스패칭이 가능해야 한다. 본 연구에서는 차세대 반도체 환경인 450mm 웨이퍼 생산 환경에서 중요한 역할을 하는 클러스터 툴에 대해 분석하고 클러스터 툴에서 웨이퍼의 작업순서를 결정할 수 있는 디스패칭 알고리즘을 제안한다.

• IE interfaces
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• v.25 no.1
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• pp.127-133
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• 2012

This paper considers the preventive maintenance scheduling problem of the cluster tool which is one of the most important manufacturing equipments in the next-generation semiconductor production environment. We define a random process that expresses the successive amount of chemicals accumulating inside the tool. Based on the renewal theory, we find the expected value and probability distribution of the time that the amount of accumulated chemicals exceeds a predetermined level. For a given probability that the accumulated chemicals exceeds the predetermined level we present a method to obtain the number of chamber operations to perform the preventive maintenance of that chamber. In addition, a method to get the preventive maintenance schedule for the whole cluster tool is presented. A numerical example is provided to illustrate our method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.375-375
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• 2010

CdTe as an absorber material is widely used in thin film solar cells with the heterostructure due to its almost ideal band gap energy of 1.45 eV, high photovoltaic conversion efficiency, low cost and stable performance. The deposition methods and preparation conditions for the fabrication of CdTe are very important for the achievement of high solar cell conversion efficiency. There are some rearranged reports about the deposition methods available for the preparation of CdTe thin films such as close spaced sublimation (CSS), physical vapor deposition (PVD), vacuum evaporation, vapor transport deposition (VTD), closed space vapor transport, electrodeposition, screen printing, spray pyrolysis, metalorganic chemical vapor deposition (MOCVD), and RF sputtering. The RF sputtering method for the preparation of CdTe thin films has important advantages in that the thin films can be prepared at low growth temperatures with large-area deposition suitable for mass-production. The authors reported that the optical and electrical properties of CdTe thin film were closely connected by the thickness-uniformity of the film in the previous study [1], which means that the better optical absorbance and the higher carrier concentration could be obtained in the better condition of thickness-uniformity for CdTe thin film. The thickness-uniformity could be controlled and improved by the some process parameters such as vacuum level and RF power in the sputtering process of CdTe thin films. However, there is a limitation to improve the thickness-uniformity only in the preparation process [1]. So it is necessary to introduce the external or additional method for improving the thickness-uniformity of CdTe thin film because the cell size of thin film solar cell will be enlarged. Therefore, the authors firstly applied the chemical mechanical polishing (CMP) process to improving the thickness-uniformity of CdTe thin films with a G&P POLI-450 CMP polisher [2]. CMP process is the most important process in semiconductor manufacturing processes in order to planarize the surface of the wafer even over 300 mm and to form the copper interconnects with damascene process. Some important CMP characteristics for CdTe were obtained including removal rate (RR), WIWNU%, RMS roughness, and peak-to-valley roughness [2]. With these important results, the CMP process for CdTe thin films was performed to improve the thickness-uniformity of the sputtering-deposited CdTe thin film which had the worst two thickness-uniformities of them. Some optical properties including optical transmittance and absorbance of the CdTe thin films were measured by using a UV-Visible spectrophotometer (Varian Techtron, Cary500scan) in the range of 400 - 800 nm. After CMP process, the thickness-uniformities became better than that of the best condition in the previous sputtering process of CdTe thin films. Consequently, the optical properties were directly affected by the thickness-uniformity of CdTe thin film. The absorbance of CdTe thin films was improved although the thickness of CdTe thin film was not changed.