• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.9
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• pp.759-764
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• 2003

Recently, CMP (chemical mechanical polishing) technology has been widely used for global planarization of multi-level interconnection for ULSI applications. However, COO (cost of ownership) and COC (cost of consumables) were relatively increased because of expensive slurry. In this paper, we have studied the possibility of recycle of roused silica slurry in order to reduce the costs of CMP slurry. The post-CMP thickness and within-wafer non-uniformity (WIWNU) wore measured as a function of different slurry composition. As an experimental result, the performance of reused slurry with annealed silica abrasive of 2 wt％ contents was showed high removal rate and low non-uniformity. Therefore, we propose two-step CMP process as follows , In tile first-step CMP, we can polish the thick and rough film surface using remaked slurry, and then, in the second-step CMP, we can polish the thin film and fine pattern using original slurry. In summary, we can expect the saying of high costs of slurry.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.9
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• pp.1005-1012
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• 2014

Gears are critical elements in automobiles, and their use as power transmitting machine elements in engineering applications is quite extensive. In the areas of contact between gear teeth, the condition of a gear is likely to deteriorate due to contact fatigue, wear, material defects, lubrication failure, etc. Thus, it is necessary to monitor its condition to ensure smooth power transmission. Gear teeth deterioration causes failures such as abrasive wear, scuffing, pitting, and spalling. These failures lead to a higher level of vibration signals in the gear system. This paper presents the results of an experiment on the surface fatigue wear of a spur gear system. The correlation between the estimated specific film thickness, statistical parameter of the vibration signals, and Stribeck curve was considered in this study.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.05a
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• pp.226-234
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• 2002

A systematic study of the role of transfer films on friction properties was performed with various temperatures in the brake system. An NAO friction material specimens containing 9 ingredients were tested using a pad-on-disk type friction tester A new method of measuring the transfer film thickness was developed by considering the electrical resistance of the transfer film using a 4-point probe technique. The properties of transfer film such as surface morphology and film distribution vaied according to the relative amount of graphite and magnesium oxide. By using SEM, it was possible to obtain information about the chemical composition of the transfer film. Results showed that there detected a threshold value of the relative amount of a two active materials to maintain a certiain thickness of a transfer film. Results also showed that formation of friction layer generated on the friction surface was strongly affected by chemical action of two ingredients during sliding due to chemical reaction of solid lubricants at different interface temperature. The results suggested that no apparent relationship between transfer film thickness and the average friction coefficient was founded and friction characteristics were affected more by the property of the solid lubricant and abrasive in the material.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.1068-1071
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• 2001

Recently, the minimum line width shows a tendancy to decrease and the multi-level to increase in semiconductor. Therefore, a planarization technique is needed, which chemical polishing(CMP) is considered as one of the most important process. CMP accomplishes a high polishing performance and a global planarization of high quality. But there are several defects in CMP such as microscratches, abrasive contaminations, and non-uniformity of polished wafer edges. Spin Etching can improve the defects of CMP. It uses abrasive-free chemical solution instead of slurry. Wafer rotates and chemical solution is simultaneously dispensed on a whole surface of the wafer. Thereby chemical reaction is occurred on the surface of wafer, material is removed. On this study, TEOS film is removed by CMP and Spin Etching, the results are estimated at a viewpoint of material removal rate(MRR) and within wafer non-uniformity(WIWNU).

• Tribology and Lubricants
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• v.20 no.1
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• pp.1-6
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• 2004

In order to identify the effect of lubricant films on abrasive abilities of diamond films, wear rates of Ruby balls slid over as grown diamond films and polytetrafluoroethylene films coated diamond films were compared by using pin-on-disk tribometer. Wear scars of Ruby balls were measured by SEM. Results showed that wear rates of Ruby balls slid over polytetrafluoroethylene coated diamond films were about 4 times lager than as grown diamond films. Coefficients of friction decreased with sliding distance at diamond disks but were almost unchanged at polytetrafluoroethylene coated ones. These results came from behaviors of wear debris, which adhered more strongly in the tracks of as grown diamond films than polytetrafluoroethylene coated ones.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.493-494
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• 2006

SU-8 can be implemented as a mask for micro Abrasive Jet Machining (micro-AJM) process [1]. In this paper, we will evaluate the quality of micro grooving result on glass substrate by micro-AJM process which using SU-8 as a mask. It was evaluated on width and edge profile of the micro grooving. The result was having distortion compare with the master film used to pattern the SU-8 mask. The value of distortion with other properties which came along with it, such as depth and surface roughness, can be optimized in order to fabricate micro-channel for micro-fluidic application.

• Journal of Welding and Joining
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• v.19 no.1
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• pp.95-103
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• 2001

The properties of the detonation sprayed cermet coating are investigated through the mechanical, corrosion and erosion test. The test results are also compared with the properties of the substrate materials, STS 329J1, dual phase stainless steel and the plasma sprayed cermet coatings. The two kinds of carbide cermet power, WC+NiCr, Cr$_3$C$_2$+NiCr were used in this experiment. The experimental results showed that the anti-corrosive and anti-erosive properties of the detonation sprayed cermet coatings are superior to the plasma sprayed cermet coatings. The WC+NiCr cermet coating appears to be more effective than Cr$_3$C$_2$+NiCr cermet coating in abrasive erosion environment, whereas the Cr$_3$C$_2$+NiCr cermet coatings are more effective in cavitation erosion environment.

• Tribology and Lubricants
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• v.25 no.1
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• pp.49-55
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• 2009

The frictional properties of automotive brake pads with four different ceramic materials such as magnesia, hematite, alumina, and zircon were investigated. A Krauss type friction tester using gray iron disks was used to examine the friction coefficient, intensity of friction force oscillation, and the tribe-surfaces. Results showed that the friction coefficient increased as the hardness of abrasives increases. Friction oscillation was also increased with hardness of the abrasives. However, the friction materials containing less abrasive particles produced stable friction films on the sliding surface. The transition between two-body and three body abrasion during sliding also played a crucial role in destructing the friction film on the pad surface and in determining various frictional properties.

• Journal of the Korean Society for Precision Engineering
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• v.7 no.2
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• pp.113-123
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• 1990

To study deleterious effects of contaminants contained in lubricating systems, the effects of fine alumina particle concentration and size on the critical failure load, friction and wear characteristic were examined on boundary lubrication condition using the four ball machine. The following conclusions are deduced: The abrasive is found to cause a transition from mild wear to severe wear at less severe conditions than with clean oil. In mild wear region the friction and wear increase with particle size and concentration, but in severe wear region do not exhibit any definite trend. In relation to film thinckness there is a threshold of particle size beyond which the failure load no longer decreases with particle size.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.5
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• pp.385-392
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• 2016

Recently in the display industry, demands for high-luminance and resolution of display devices have been steadily increasing. Generally, micro linear patterns are applied to an optical film in order to improve its properties of light. However, these patterns are easily viewed to eyes and moire phenomenon can be occurred. Micro random patterns are proposed as a method to solve these problems, increasing light-luminance and light-diffusion. However, conventional pattern manufacturing technologies have long processing times and high costs making it difficult to apply to large area molds. In order to combat this issue, micro-random patterns are formed by using a roll to plate indentation method along with abrasive paper tools composed of AlSiO2, SiC, and diamond grains. Also, forming properties, such as size and fill-factor of random patterns, are analyzed depending on type, mesh of abrasive paper tools, and indentation forces.