• 한국전기전자재료학회논문지
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• 제14권7호
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• pp.557-561
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• 2001

Chemical mechanical polishing (CMP) process has been widely used to planarize dielectric layers, which can be applied to the integraded circuits for sub-micron technology. Despite the increased use of CMP process, it is difficult to accomplish the global planarization of in the defect-free inter-level dielectrics (ILD). Especially, defects such as micro-scratch lead to severe circuit failure which affect yield. CMP slurries can contain particles exceeding 1㎛ in size, which could cause micro-scratch on the wafer surface. The large particles in these slurries may be caused by particles agglomeration in slurry supply line. To reduce these defects, slurry filtration method has been recommended in oxide CMP. In this work, we have studied the effects of filtration and the defect trend as a function of polished wafer count using various filters in inter-metal dielectrics(IMD)-CMP process. The filter installation in CMP polisher could reduce defects after IMD-CMP process. As a result of micro-scratch formation, it is shown that slurry filter plays an important role in determining consumable pad lifetime. The filter lifetime is dominated by the defects. We have concluded that slurry filter lifetime is fixed by the degree of generating defects.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.335-338
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• 2003

Chemical mechanical polishing (CMP) process has been widely used to planarize dielectric layers, which can be applied to the integrated circuits for sub-micron technology. Despite the increased use of CMP process, it is difficult to accomplish the global planarization of in the defect-free inter-layer dielectrics (ILD). Especially, defects such as micro-scratch lead to severe circuit failure which affect yield. CMP slurries can contain particles exceeding $1\;{\mu}m$ in size, which could cause micro-scratch on the wafer surface. In this paper, we have studied aging effect the of CMP sin as a function of particle size. We prepared and compared the self-developed silica slurry by adding of abrasives before and after annealing. As our preliminary experiment results, we could be obtained the relatively stable slurry characteristics comparable to original silica slurry in the slurry aging effect.

• 열처리공학회지
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• 제2권2호
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• pp.33-37
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• 1989

In order to improve hardness uniformity of standard-hardness blocks. experimental procedure was designed using Taguchi Method. For this purpose the following factors were studied: austenitizing temperature, tempering condition, grinding condition, subzero treatment, lapping time, $15{\mu}m$ polishing time, final polishing time. These factors were processed and then ten hardness values were measured on each specimen. SN (signal to noise) ratio for each condition was calculated with standard variations of these values. Finally, from the calculated value of ANOVA on SN ratios, the lapping time was found to be the main factor Better uniformity with longer lapping time implies that residual stress that was formed after quenching is a dominent parameter that affects on the uniformity of hardness. Therefore, step-quenching method was adapted to minimize the residual stress. By this modification of quenching procedure, the hardness uniformity was improved remarkably and the yield ratio was increased from 55% to 88%.

• 한국식품저장유통학회:학술대회논문집
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• 한국식품저장유통학회 2003년도 제23차 추계총회 및 국제학술심포지움
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• pp.46-50
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• 2003

In order to develop a new variety of rice that adapts to the climate of Aomori prefecture and possesses characteristics suitable for production of high quality Japanese sake, artificial cross experiments were executed between Yamadanishiki, which is widely used nationwide as an authentic variety of rice for sake production, and Hanafubuki, which was peviously developed by Aomori prefecture. An excellent hybrid, named Hanaomoi, was selected and fixed by a series of selection experiments and systematic cultivation. Unpolished Hanaomoi rice contained less amount of protein than Yamadanishiki and Hanafubuki. Unpolished rice of Hanaomoi was harder than Yamadanishiri and Hanafubuki, therefore polishing treatment was done in high yield and one could obtain a high degree of polish on the rice(namely 40% polishing). These features are advantageous to production of high quality of sake.Test brewing using 40% polished Hanaomoi gave rise to a characteristic sake that contained a slightly higher amount of alcohol and flavor components than Yamadanishiki and Hanafubuki. Sensory tests concluded that sake from Hanaomoi was as superior as the one from authentic Yamadanishiki. Hanaomoi is a promising variety of rice suitable for production of a high quality sake exclusive to Aomori prefecture.

• Journal of Biosystems Engineering
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• 제33권5호
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• pp.362-369
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• 2008

There is developing interest in precision agriculture in Korea, despite the fact that typical Korean fields are less than 1 ha in size. Describing within-field variability in typical Korean production settings is a fundamental first step toward determining the size of management zones and the inter-relationships between limiting factors, for establishment of site-specific management strategies. Measurements of rice (Oriza Sativa L) yield, chlorophyll content, and soil properties were obtained in a small (100-m by 30-m) Korean rice paddy field. Yield data were manually collected on 10-m by 5-m grids (180 samples with 3 samples in each of 60 grid cells) and chlorophyll content was measured using a Minolta SPAD 502 in 2-m by 2-m grids. Soil samples were collected at 275 points to compare results from sampling at different scales. Ten soil properties important for rice production in Korea were determined through laboratory analyses. Variogram analysis and point kriging with and without median polishing were conducted to determine the variability of the measured parameters. Influence of variogram model selection and other parameters on the interpretation of the data was investigated. For many of the data, maximum values were greater than double the minimum values, indicating considerable spatial variability in the small paddy field, and large-scale spatial trends were present. When variograms were fit to the original data, the limits of spatial dependency for rice yield and SP AD reading were 11.5 m and 6.5 m, respectively, and after detrending the limits were reduced to 7.4 m and 3.9 m. The range of spatial dependency for soil properties was variable, with several having ranges as short as 2 m and others having ranges greater than 30 m. Kriged maps of the variables clearly showed the presence of both large-scale (trend) variability and small-scale variability in this small field where it would be reasonable to expect uniformity. These findings indicate the potential for applying the principles and technology of precision agriculture for Korean paddy fields. Additional research is needed to confirm the results with data from other fields and crops.d similar tendency with the result for the frequency less than 20 Hz, but the width of change was reduced highly.

• Bulletin of the Korean Chemical Society
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• 제32권7호
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• pp.2227-2232
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• 2011

The new metrology, Advanced Poly-silicon Ultra-Trace Profiling (APUTP), was developed for measuring bulk Cu and Ni in heavily boron-doped silicon wafers. A Ni recovery yield of 98.8% and a Cu recovery yield of 96.0% were achieved by optimizing the vapor phase etching and the wafer surface scanning conditions, following capture of Cu and Ni by the poly-silicon layer. A lower limit of detection (LOD) than previous techniques could be achieved using the mixture vapor etching method. This method can be used to indicate the amount of Cu and Ni resulting from bulk contamination in heavily boron-doped silicon wafers during wafer manufacturing. It was found that a higher degree of bulk Ni contamination arose during alkaline etching of heavily boron-doped silicon wafers compared with lightly boron-doped silicon wafers. In addition, it was proven that bulk Cu contamination was easily introduced in the heavily boron-doped silicon wafer by polishing the wafer with a slurry containing Cu in the presence of amine additives.

• Transactions on Electrical and Electronic Materials
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• 제8권1호
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• pp.1-4
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• 2007

This paper discusses two approaches for pre-polishing optimization of oxide chemical mechanical planarization (CMP) that can be used as alternatives to the commonly applied dummy structure insertion in shallow trench isolation (STI) and replacement gate (RG) technologies: reverse nitride masking (RNM) and oxide etchback (OEB). Wafers have been produced using each optimization technique and CMP tests have been performed. Dishing, erosion and global planarity have been investigated with the help of conductive atomic force microscopy (C-AFM). The results demonstrate the effectiveness of both techniques which yield excellent planarity without dummy structure related performance degradation due to capacitive coupling.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기물성,응용부문
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• pp.103-104
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• 2006

$Pb(Zr,Ti)O_3(PZT)$ is very attractive ferroelectric materials for ferroelectric random access memory (FeRAM) applications because of its high polarization ability and low process temperature. However, Chemical Mechanical Polishing (CMP) pressure and velocity must be carefully adjusted because FeRAM shrinks to high density devices. The contaminations such as slurry residues due to the absence of the exclusive cleaning chemicals are enough to influence on the degradation of PZT thin film capacitors. The surface characteristics of PZT thin film were investigated by the change of process parameters and the cleaning process. Both the low CMP pressure and the cleaning process must be employed, even if the removal rate and the yield were decreased, to reduce the fatigue of PZT thin film capacitors fabricated by damascene process. Like this, fatigue characteristics were partially controlled by the regulation of the CMP process parameters in PZT damascene process. And the exclusive cleaning chemicals for PZT thin films were developed in this work.

• KSBB Journal
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• 제21권1호
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• pp.1-10
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• 2006

식물세포배양으로부터 항암제 paclitaxel의 생산을 위해 회수 및 정제는 산업적 공정에 있어서 필수적이다. 본 총설은 식물세포배양으로부터 고순도, 고수율의 paclitaxel 생산을 위한 대량 회수 및 정제 방법을 기술하고자 한다. 또한 이러한 분리 및 정제 공정은 추출, 전 처리, 정제, 제품화 단계를 총괄하여 최종 제품의 요구조건들 즉, 순도, 잔류용매, 제품형태, 불순물 함량, 엔도톡신 함량 등을 충족시킬 수 있도록 최적화되어야 한다. 이러한 관점에서 본 총설은 산업화 단계에서의 의약품 생산 및 품질관리에 상당히 유용하게 활용될 수 있을 것으로 판단된다.

• 마이크로전자및패키징학회지
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• 제27권3호
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• pp.89-93
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• 2020

반도체 패키지의 경박단소화로 인해 발생하는 복잡한 휨 거동은 내부 응력을 발생시켜 박리나 균열과 같은 다양한 기계적인 결함을 야기한다. 이에 따른 수율 감소를 막기 위해 휨 거동을 정확하게 예측하려는 노력은 다양한 측면에서 그 접근이 이루어지고 있다. 이 중 패키지를 구성하는 주 재료인 실리콘 웨이퍼는 일반적으로 균질한 물질로 취급되어 열에 의한 휨 거동은 전혀 없는 것으로 묘사된다. 그러나 실리콘을 얇게 가공하기 위해서 진행되는 그라인딩과 폴리싱에 의해 상온에서 휨이 발생한다는 사실이 보고되어 있고, 이는 표면에 형성되는 damage layer가 두께 방향으로 불균질함을 발생시키는 것으로부터 기인한다. 이에 본 논문에서는 반도체 패키징 공정 중 최고온 공정 과정인 solder reflow 온도에서 단면 연마된 웨이퍼가 나타내는 휨 거동을 측정하고, 이러한 휨 량이 나타나는 원인을 연마된 면과 그렇지 않은 면의 열팽창계수를 측정함으로써 밝혀내었다. 측정에는 미세 변형률과 형상이 모두 측정 가능한 3차원 디지털 이미지 상관법(Digital Image Correlation; DIC)을 이용하였다.