• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.90-93
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• 2000

In this study, the rise throughput and the stability in fabrication of device can be obtained by applying of CMP process to STI structure in 0.18um semiconductor device. To employ in STI CMP, the reverse moat process has been added thus the process became complex and the defects were seriously increased. Removal rates of each thin films in STI CMP was not equal hence the devices must to be effected, that is, the damage was occured in the device dimension in the case of excessive CMP process and the nitride film was remained on the device dimension in the case of insufficient CMP process than these defects affect the device characteristics. To resolve these problems, the development of slurry for CMP with high removal rate and high selectivity between each thin films was studied then it can be prevent the reasons of many defects by reasons of many defects by simplification of process that directly apply CMP process to STI structure without the reverse moat pattern process.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.185-188
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• 2001

Chemical mechanical polishing(CMP) process is widely used for global planarization of inter-metal dielectric (IMD) layer and inter-layer dielectric (ILD) for deep sub-micron technology. However, as the IMD and ILD layer gets thinner, defects such as micro-scratch lead to severe circuit failure, which affect yield. In this paper, for the improvement of CMP Process, deionized water (DIW) pressure, purified $N_2$ (P$N_2$) gas, slurry filter and high spray bar were installed. Our experimental results show that DIW pressure and P$N_2$ gas factors were not related with removal rate, but edge hot-spot of patterned wafer had a serious relation. Also, the filter installation in CMP polisher could reduce defects after CMP process, it is shown that slurry filter plays an important role in determining consumable pad lifetime. The filter lifetime is dominated by the defects. However, the slurry filter is impossible to prevent defect-causing particles perfectly. Thus, we suggest that it is necessary to install the high spray bar of de-ionized water (DIW) with high pressure, to overcome the weak-point of slurry filter. Finally, we could expect the improvements of throughput, yield and stability in the ULSI fabrication process.

• 한국멀티미디어학회논문지
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• 제6권5호
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• pp.831-841
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• 2003

무선 ATM 망에서, 이동 단말기들은 유선 ATM 망의 단말기와 같은 기능과 QoS를 제공해 야 한다. 그러므로, 기지국 스케줄러에게 이동 단말기들의 ATM 셀 도착에 대한 정보가 빠르게 전달되는 것이 중앙 집중방식으로 제어되는 ATM 기반 MAC 프로토콜의 중요한 항목이다. 그러나, 다수 개의 무선 단말기들이 상향 링크를 통해 상호 경쟁적인 방법으로 데이터 전송을 요구하는 과정에서 충돌이 발생되고, 충돌에 의한 재전송 때문에 처리율이 감소되고 전송 지연이 증가하게 된다. 본 논문에서는 예약을 요청하는 단말기 수를 통계적으로 예측하고 사후 처리율을 고려하여 최적화된 request mini-slot의 개수를 결정하는 MAC 프로토콜을 제안한다. 시뮬레이션 결과에서 제안한 프로토콜이 지연과 처리율에서 높은 성능을 보임을 알 수 있었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권4호
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• pp.1884-1903
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• 2019

Device-to-Device (D2D) communications can provide proximity based services in the future 5G cellular networks. It allows short range communication in a limited area with the advantages of power saving, high data rate and traffic offloading. However, D2D communications may reuse the licensed channels with cellular communications and potentially result in critical interferences to nearby devices. To control the interference and improve network throughput in overlaid D2D cellular networks, a novel channel assignment approach is proposed in this paper. First, we characterize the performance of devices by using Poisson point process model. Then, we convert the throughput maximization problem into an optimal spectrum allocation problem with signal to interference plus noise ratio constraints and solve it, i.e., assigning appropriate fractions of channels to cellular communications and D2D communications. In order to mitigate the interferences between D2D devices, a cluster-based multi-channel assignment algorithm is proposed. The algorithm first cluster D2D communications into clusters to reduce the problem scale. After that, a multi-channel assignment algorithm is proposed to mitigate critical interferences among nearby devices for each D2D cluster individually. The simulation analysis conforms that the proposed algorithm can greatly increase system throughput.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1065-1068
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• 2003

The nano imprint process is one of the next generation lithography has been mentioned as one of major nanoreplication techniques because it is simple process, low cost, high replication fidelity and relatively high throughput. This process requires a surface contact between a template with patterns and a wafer on a stage. After contact, the vertical moving the template to the wafer causes some directional motions of the stage. Thus the stage must move according to the motions of the template to avoid the damage of the transferred patterns on the wafer. This study is to develop the wafer stage with a passive compliance to overcome the damage. This stage is designed with the concept like that it has a monolithic, symmetry and planar 6-DOF mechanism.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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• pp.665-667
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• 2005

VIATRON TECHNOLOGIES has developed FE-RTP system that enables LTPS LCD and AMOLED manufacturers to produce poly-Si films at low cost, high throughput, and high yield. The system employs sequential heat treatment methods using temperature control and rapid thermal processor modules. The temperature control modules provide exceptionally uniform heating and cooling of the glass substrates to within ${\pm}2^a\;C$. The rapid thermal process that combines heating with field induction accelerates the treatment rates. The new FE-RTP system can process $730{\times}920mm$ glass substrates as thin as 0.4 mm. The uniform nature of poly-Si films produced by FE-RTP resulted in AMOLED panels with no laser-Muras. Furthermore, FE-RTP system also showed superior performances in other heat treatment processes involved in poly-Si TFT fabrications, such as dopant activation, gate oxide densification, hydrogenation, and pre-compaction.

• 한국초전도ㆍ저온공학회논문지
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• 제9권4호
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• pp.1-6
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• 2007

We describe methods for depositing high temperature superconducting films on textured metal tapes by reactive co-evaporation (RCE). We discuss how RCE can be used to deposit on moving tape in a continuous fashion in a Garching-style process. Results are presented on films deposited by RCE at Los Alamos on IBAD-MgO textured tapes. The performance achieved, attaining over 500A/cm-width in self-field at 75.5 K, is competitive with the best results obtained by other processes for coated conductors. Tape production throughput is critical for the economics of the process and high deposition rates achieved in RCE are attractive for this. We present a detailed cost analysis model for HTS deposition using an RCE Garching process. The results indicate that HTS deposition can cost $<$5/kA{\cdot}m$ in a scaled up manufacturing environment.

• 반도체디스플레이기술학회지
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• 제16권4호
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• pp.68-74
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• 2017

Nanoimprint lithography (NIL) is a next generation technology for fabrication of micrometer and nanometer scale patterns. There have been considerable attentions on NIL due to its potential abilities that enable cost-effective and high-throughput nanofabrication to the display device and semiconductor industry. Up to now there have been a lot of researches on thermal NIL, but most of them have been focused on polymer deformation in the molding process and there are very few studies on the cooling and demolding process. In this paper a cooling process of the polymer resist in thermal NIL is analyzed with finite element method. The modeling of cooling process for mold, polymer resist and substrate is developed. And the cooling process is numerically investigated with the effects of imprinting temperature and residual layer thickness of polymer resist on stress distribution of the polymer resist. The results show that the lower imprinting temperature, the higher the maximum von Mises stress and that the thicker the residual layer, the greater maximum von Mises stress.

• 전자공학회논문지A
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• 제33A권2호
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• pp.59-68
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• 1996

In this paper, we propose two types of WDMA protocol for multi-wavelength optical networks that have a dedicated control channel. Protocol type I is designed for the case that the number of nimislots is less than the number of nodes (La${\ge}$M). Proposed protocols employ the aging scheme to guarantee a fairness in the process of channel allocation. The perfomrance of proposed protocols are evaluated in terms of throughput and delay with variations in offered load. Simulation results show that the proposed protocols have superior performance to conventional protocols.

• ETRI Journal
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• 제33권6호
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• pp.831-840
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• 2011

This paper focuses on codebook-based precoding for space-division multiple access/orthogonal frequency-division multiple access (SDMA-OFDMA) systems aiming to guarantee high throughput for their users as well as to mitigate interference to fixed satellite service (FSS). A systematic design of SDMA codebook for subband-based OFDMA is proposed, which forms multiple orthogonal beams with common spatial null in the direction of a victim FSS earth station (ES). The design enables both transmitter and receiver to independently construct identical codebook by sharing only on the direction angle of an FSS ES, which takes fewer overhead bits than Gram-Schmidt process, a general method satisfying our design criterion. A system-level throughput evaluation shows that the proposed precoding provides superior performance over existing spectrum sharing method, that is, subband deactivation. The spectrum sharing analysis shows that the proposed precoding, even with an estimation error of the direction angles of an FSS ES, causes lower interference than existing precoding, knockdown precoding.