• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.435-437
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• 2002

Polishing of copper, a process called copper chemical mechanical polishing, is a critical, intermediate step in the planarization of silicon wafers. During polishing, the electrodeposited copper films are removed by slurries: and the differential polishing rates between copper and the surrounding silicon dioxide leads to a greater removal of the copper. The differential polishing develops dimples and furrows; and the process is called dishing and erosion. In this work, we present the results of experiments on dishing and erosion of copper-CMP, using patterned silicon wafers. Results are analyzed for the pattern factors and properties of the copper layers. Three types of pads - plain, perforated, and grooved - were used for polishing. The effect of slurry chemistries and pad soaking is also reported.

• Transactions on Electrical and Electronic Materials
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• 제7권4호
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• pp.163-166
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• 2006

The dishing and the erosion were evaluated on the tungsten CMP process with conventional and new developed slurry. The tungsten thin film was polished by orbital polishing equipment. Commercial pattern wafer was used for the evaluation. Both slurries were pre tested on the oxide region on the wafer surface and the removal rate was not different very much. At the pattern density examination, the erosion performance was increased at all processing condition due to the reduction of thickness loss in new slurry. However, the dishing thickness was not remarkably changed at high pattern density despite of the improvement at low pattern density. At the large pad area, the reduction of dishing thickness was clearly found at new tungsten slurry.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1997년도 제25회 춘계학술대회
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• pp.69-73
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• 1997

Microwave Plasma assisted CVD (Chemical Vapor Deposition) and DC Plasma CVD were used to prepare thin and thick diamond film, respectively. Diamond coated silicon nitride and fiee standing diamond thick film were eroded by silicon carbide particles. The velocity of the solid particle was about 220m/sec. Phase transformation and the other crack formation were investigated by using Raman spectroscopy and microscopy.

• 아시안잔디학회지
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• 제10권1호
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• pp.49-59
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• 1996

This report is researched on the cause and mechanism of soil erosion in comparison among Kwangnung, Mt. Kaya, Mt. Chili, and Mt. Soorak by physical and chemical analyses of their for- est soils. Clay, silt, and fine sand of Mt. Soorak are far less than those of Mt. Chili, Mt. Kaya, and Kwangnung area while coarse sand is very high level. The clay ratio of soil at Mt. Soorak is the most high level in comparison with that of other area. Denudation at Mt. Soorak, therefore, is cause of erosion by the result of transportation of soil particles. The eroding velocity increase for larger particle size and stronger cohesion between soil particles. Very fine sand, silt, and clay can be present in suspension near the bottom and the size of the particles in suspension depends upon the velocity of the current near the bottom and the roughness of the bottom. Key words: Theoretical analyses, Soil erosion and conservation, Forest soils.

• 한국전기전자재료학회논문지
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• 제18권4호
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• pp.321-326
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• 2005

Chemical mechanical polishing(CMP) process is essential technology to be applied to manufacturing the dielectric layer and metal line in semiconductor devices. It has been known that overpolishing in CMP depends on pattern selectivity as a function of density and pitch, and use of fixed abrasive pad(FAP) is one method which can improve the pattern selectivity. Thus, dishing & erosion defects can be reduced. This paper introduces the manufacturing technique of FAP using hydrophilic polymers with swelling characteristic in water and explains the self-conditioning phenomenon. When applied to tungsten blanket wafers, the FAP resulted in appropriate performance in point of uniformity, material selectivity and roughness. Especially, reduced dishing and erosion was observed in CMP of tungsten pattern wafer with the proposed FAP.

• 한국세라믹학회지
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• 제46권5호
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• pp.456-461
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• 2009

Chemical composition and status of chemical bonding of the YAG($Y_3Al_5O_{12}$) ceramics after the exposure to fluorine plasma have been investigated using X-ray photoelectron spectroscopy, with the analysis on its erosion behavior. On the surface, F showed the maximum content, decreasing with depth, meanwhile the cation composition remained almost constant, irrespective of the position. The peaks due to Y in the reaction layer consisted of two kinds, showing the Y-O and Y-F bonds. These surface modifications under fluorine plasma seem to promote the erosion of the YAG ceramics. Excess addition of $Al_2O_3$ or $Y_2O_3$ into stoichiometric YAG produced 2nd phases of $Al_2O_3$ and $YAlO_3$, respectively, resulting in the slight difference in the local erosion rates. But, the overall average erosion rate was not sensitive to such excess additions of $Al_2O_3$ or $Y_2O_3$.

• 한국물환경학회지
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• 제23권4호
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• pp.518-526
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• 2007

There have been serious soil erosion and water pollution problems caused by highland agriculture practices at Doam-dam watershed. Especially agricultural activities, chemical and organic fertilizer and pesticide applications, soil reconditioning to maintain soil fertility are known as primary causes of soil erosion and water qaulity degradation in the receiving water bodies. Among these, soil reconditioning can accelerate soil erosion rates. To develop soil erosion prevention practices, it is necessary to estimate the soil erosion from the watershed. Thus, the Universal Soil Loss Equation (USLE) model has been developed and utilized to assess soil erosion. However, the USLE model cannot be used at watershed scale because it does not consider sediment delivery ratio (SDR) for watershed application. For this reason, the Sediment Assessment Tool for Effective Erosion Control (SA TEEC) was developed to assess the sediment yield at any point in the watershed. The USLE-based SA TEEC system can estimate the SDR using area-based SDR and slope-based SDR module. In this study, the SATEEC system was used to estimate soil erosion and sediment yield at the Doam-dam watershed using the soil properties from reconditioned agricultural fields. Based on the soil sampling and analysis, the US LE K factor was calculated and used in the SA TEEC system to analyze the possible errors of previous USLE application studies using soil properties from the digital soil map, and compared with that using soil properties obtained in this study. The estimated soil erosion at the Doam-dam watershed without using soil properties obtained in the soil sampling and analysis is 1,791,400 ton/year (123 ton/ha/year), while the soil erosion amount is 2,429,900 ton/year (166.8 ton/ha/year) with the use of soil properties from the soil sampling and analysis. There is 35 % increase in estimated soil erosion and sediment yield with the use of soil properties from soil reconditioned agricultural fields. Since significant amount of soil erosion are known to be occurring from the agricultural fields, the soil erosion and sediment yield from only agricultural fields was assessed. The soil erosion rate is 45.9 ton/ha/year without considering soil properties from soil reconditioned agricultural fields, while 105.3 ton/ha/year after considering soil properties obtained in this study, increased in 129%. This study shows that it is very important to use correct soil properties to assess soil erosion and sediment yield simulation. It is recommended that further studies are needed to develop environment friendly soil reconditioning method should be developed and implemented to decrease the speed of soil erosion rates and water quality degradation.

• 대한토목학회논문집
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• 제28권1B호
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• pp.125-135
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• 2008

본 연구의 목적은 금강하구의 표층에 분포하는 점착성 퇴적물의 침식매개변수를 정량적으로 산정하는 것이다. 또한 본 연구는 침식매개변수들의 금강하구역 내에서의 지엽적 계절적 변화에 대한 조사와 타 지역 분석 결과와의 비교/분석을 통한 공간적 변화에 대한 조사를 포함한다. 점착성 퇴적물의 침식특성은 기본적으로 퇴적물 자체의 물리 화학적 특성에 의해 크게 영향을 받으므로, 본 연구는 또한 퇴적물의 이러한 기본특성이 침식특성에 미치는 영향에 대한 정성적 분석을 포함한다. 침식실험은 전북대 환형수조를 이용하여 균일저면 조건하에서 수행되었으며, 저면밀도와 바닥전단응력을 변화시키면서 총 16회의 실험이 수행되었다. 실험결과에 따르면, 금강하구역 점착성 퇴적물은 저면밀도 $1.14{\sim}1.38g/cm^3$ 범위에서 침식한계전단응력(${\tau}_{ce,s}$)은 $0.19{\sim}0.41N/m^2$, 침식률 계수(${\varepsilon}_{M,s}$)는 $54.26{\sim}7.70mg/cm^2{\cdot}hr$ 범위의 값을 갖는 것으로 나타났다. 또한 산정된 침식 매개변수들은 타 지역 점착성 퇴적물과 비교시 정량적으로 그 값이 크게 다른 것으로 나타났으나, 금강하구역 내에서의 지엽적/계절적 변화는 미미한 것으로 나타났다.

• 수산해양기술연구
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• 제30권4호
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• pp.312-319
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• 1994

Recently, with the rapid development in the industries such as an iron mill and chemical plants, there is enlarged by the use of the piping. Sepecially, the piping connected with a fluid, if it is increase the speed of running fluid, ought to generate cavitation phenomenon with unbalanced pressure. So, the cavitation phenomenon cause serious damage of the piping, because it generate erosion and corrosion in the piping. In this study, the steel pipe piping water (SPPW) and SPPW on weldment were tested by using of cavitation-erosion test apparatus with nozzle and were investigated under the marine environment of liquid. (specific resistance : 25 $Omega$. cm) The main results obtained are as follows : 1) The total weight loss and weight loss rate of affected zone of weldment by corrosion-erosion in the sea water are more increased than that of base metal. 2) The electrode potential by corrosion-erosion in the sea water becomes less noble than that of base metal, and current density is more increased. 3) As time goes by, the total weight loss and weight loss rate by cavitation erosion-corrosion in air-liquid 2 phase flow become more increased then those in only liquid solution. but these values turn to be decreased.

• 한국재료학회지
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• 제22권11호
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• pp.587-590
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• 2012

Recently, the demand for the miniaturization of package substrates has been increasing. Technical innovation has occurred to move package substrate manufacturing steps into CMP applications. Electroplated copper filled trenches on the substrate need to be planarized for multi-level wires of less than $10{\mu}m$. This paper introduces a chemical mechanical planarization (CMP) process as a new package substrate manufacturing step. The purpose of this study is to investigate the effect of surfactant on the dishing and erosion of Cu patterns with the lines and spaces of around $10/10{\mu}m$ used for advanced package substrates. The use of a conventional Cu slurry without surfactant led to problems, including severe erosion of $0.58{\mu}m$ in Cu patterns smaller than $4/6{\mu}m$ and deep dishing of $4.2{\mu}m$ in Cu patterns larger than $14/16{\mu}m$. However, experimental results showed that the friction force during Cu CMP changed to lower value, and that dishing and erosion became smaller simultaneously as the surfactant concentration became higher. Finally, it was possible to realize more globally planarized Cu patterns with erosion ranges of $0.22{\mu}m$ to $0.35{\mu}m$ and dishing ranges of $0.37{\mu}m$ to $0.69{\mu}m$ by using 3 wt% concentration of surfactant.