• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1296-1301
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• 2003

The chemical mechanical polishing(CMP) is necessarily applied to manufacturing the dielectric layer and metal line in the semiconductor device. The conditioning of polishing pad in CMP process additionally operates for maintaining the removal rate, within wafer non-uniformity, and wafer to wafer non-uniformity. But the fixed abrasive pad(FAP) using the hydrophilic polymer with abrasive that has the swelling characteristic by water owns the self-conditioning advantage as compared with the general CMP. FAP also takes advantage of planarity, resulting from decreasing pattern selectivity and defects such as dishing due to the reduction of abrasive concentration. This paper introduces the manufacturing technique of FAP. And the tungsten CMP using FAP achieved the good conclusion in point of the removal rate, non-uniformity, surface roughness, material selectivity, micro-scratch free contemporary with the pad life-time.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.1121-1124
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• 2001

In this study, we verify th effects of pattern density on interlayer dielectric chemical mechanical polishing process based on the analysis of Preston's equation and confirm this analysis by several experiments. Appropriate modeling equation, transformed form Preston's equations used in glass polishing, will be suggested and described the effects of this modeling during pattern wafer ILD CMP. Results indicate that the modeling is well agreed to middle density structure of the die in pattern wafer, but has some error in low and high density structure of the die. Actually, the die used in Fab, was designed to have a appropriate density, therefore this modeling will be suitable for estimating the results of ILD CMP.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.715-718
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• 2001

This study uses traditional alum coagulation and sedimentation process to treat CMP wastewater from cleaning after polishing. The primary goal is to successfully recycle both solid fines and water for semiconductor manufacturing. Results indicated that CMP wastewater may be successfully treated to recover clean water and fine particles by alum coagulation. The optimum operating conditions for coagulation are as fellowing: alum dosage of 10 ppm, pH at 5, rapid mixing speed at 800 rpm, 5 min rapid mixing time, and long slow mixing time. The treated water with low turbidity and an average residual aluminum ion concentration of 0.23 ppm may be considered for reuse. The settled sludge after alum coagulation contains mainly SiO$_2$particle with a minor content of aluminum (1.7 wt%) may be considered as raw materials for glass and ceramic industry.

• 대한기계학회논문집A
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• 제33권3호
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• pp.196-200
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• 2009

Lithium niobate ($LN:LiNbO_3$) is a compound of niobium, lithium and oxygen. The characteristics of LN are piezoelectricity, ferroelectricity and photoelectricity, and which is widely used in surface acoustic wave (SAW). To manufacture LN devices, the LN surface should be a smooth surface and defect-free because of optical property, but the LN material is processed difficult b traditional processes such as grinding and mechanical polishing (MP) because of its brittleness. To decrease defects, chemical mechanical polishing (CMP) was applied to the LN wafer. In this study, the suitable parameters such as down force and relative velocity, were investigated for the LN CMP process To improve roughness, the LN CMP was performed using the parameters that were the highest removal rate among process parameters. And, evaluation of optical property was performed by the optical reflectance.

• 한국전기전자재료학회논문지
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• 제16권12S호
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• pp.1157-1164
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• 2003

This paper shows the results of atomistic modeling for the interaction between spherical nano abrasive and substrate in chemical mechanical polishing processes. Atomistic modeling was achieved from 2-dimensional molecular dynamics simulations using the Lennard-Jones 12-6 potentials. The abrasive dynamics was modeled by three cases, such as slipping, rolling, and rotating. Simulation results showed that the different dynamics of the abrasive results the different features of surfaces. This model can be extended to investigate the 3-dimensional chemical mechanical polishing processes.

• 반도체디스플레이기술학회지
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• 제10권4호
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• pp.47-51
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• 2011

We investigated the substrate surface polishing by the spherical rigid abrasive under the compression using classical molecular dynamics modeling. We performed three-dimensional molecular dynamic simulations using the Morse potential functions for the various slide-to-roll ratios, from 0 to 1, and then, the compressive forces acting on the spherical rigid abrasive were calculated as functions of the time and the slide-to-roll ratio. The friction coefficients obtained from the classical molecular dynamics simulations were compared to those obtained from the experiments; and found that the molecular dynamic simulation results with the slide-to-roll ratio of 0 value were in good agreement with the experimental results.

• 대한기계학회논문집A
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• 제28권11호
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• pp.1807-1812
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• 2004

The application of chemical mechanical polishing(CMP) has a long history. Recently, CMP has been used in the planarization of the interlayer dielectric(ILD) and metal used to form the multilevel interconnections between each layers. Therefore, much research has been conducted to understand the basic mechanism of the CMP process. CMP performed by the down force and the relative speed between pad and wafer with slurry is typical tribo-system. In general, studies have indicated that removal rate is relative to energy. Accordingly, in this study, CMP results will be analyzed by a viewpoint of the friction energy using friction force measurement. The results show that energy would not constant in the same removal rate conditions

• 반도체디스플레이기술학회지
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• 제21권4호
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• pp.71-76
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• 2022

We evaluated and developed a 6th generation large-size polisher in the type of face-up and Oscar. We removed the hillocks of the low temperature poly-silicon (LTPS) thin film with this polisher. The surface roughness of LTPS was lowered from 7.9 nm to 0.6 nm after CMP(chemical mechanical polishing). The thickness of the LTPS is measured through reflectance in real time during polishing, and the polishing process is completed according to this thickness. The within glass non-uniformity (WIGNU) was 6.2% and the glass-to-glass non-uniformity (GTGNU) was 2.5%, targeting the LTPS thickness of 400Å. In addition, the residual slurry after the CMP process was removed through the Core Flow PVA Brush and alkaline chemical.

• 한국세라믹학회지
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• 제50권2호
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• pp.122-126
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• 2013

The surface roughness of the inner and outer surfaces of a tube is an important requirement for nuclear fuel cladding. When an inner SiC clad tube, which is considered as an advanced Pressurized Water Cooled Reactor (PWR) clad with a three-layered structure, is fabricated by Chemical Vapor Deposition (CVD), the surface roughness of the substrate, graphite, is an important process parameter. The surface character of the graphite substrate could directly affect the roughness of the inner surface of SiC deposits, which is in contact with a substrate. To evaluate the effects of the surface roughness changes of a substrate, SiC deposits were fabricated using different types of graphite substrates prepared by the following four polishing paths and heat-treatment for purification: (1) polishing with #220 abrasive paper (PP) without heat treatment (HT), (2) polishing with #220 PP with HT, (3) #2400 PP without HT, (4) polishing with #2400 PP with HT. The average surface roughnesses (Ra) of each deposited SiC layer are 4.273, 6.599, 3.069, and $6.401{\mu}m$, respectively. In the low pressure SiC CVD process with a graphite substrate, the removal of graphite particles on the graphite surface during the purification and the temperature increasing process for CVD seemed to affect the surface roughness of SiC deposits. For the lower surface roughness of the as-deposited interlayer of SiC on the graphite substrate, the fine controlled processing with the completed removal of rough scratches and cleaning at each polishing and heat treating step was important.

• 한국기계가공학회지
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• 제16권5호
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• pp.85-90
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• 2017

Mica-glass ceramics has features such as micro-sized crystals, high strength, chemical resistance, semitransparent optical properties, etc. Due to its superior material properties, mica glass ceramics have increasing applications in dental and medical components, insulation boards, chemical devices, etc. In many applications, especially for dental and medical components, ultra-precise polishing is required. However, it is known to be a very difficult-to-grind material because of its high hardness and brittle properties. Thus, in this study, a newly developed ultra-precise polishing method is applied to obtain nano-level surface roughness of the mica glass ceramics using magnetorheological (MR) fluids and nano abrasives. Nano-sized ceria particles were used for the polishing of the mica glass ceramics. A series of experiments were performed under various polishing conditions, and the results were analyzed. A very fine surface roughness of Ra=6.127 nm could be obtained.