• Journal of the Korean Society for Precision Engineering
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• v.19 no.10
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• pp.212-220
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• 2002

The finishing process for die and mold manufacturing is very important because it influences the final quality of products. Injection molds need higher quality surface than general purpose dies and molds. Conventional polishing can not make mold surface down to nanometer roughness efficiently because of their loading and glazing. This paper focused on the development of fixed abrasive pad using water swelling mechanism of polymer binder network. Self-conditioning was recognized as the long term polishing stabilization tool without any loading or glazing because water makes fixed abrasives free by swelling of the pad. Consequently, stable nano-polishing process has been applied on the injection mold, from the experimental results with polished surface roughness of Ra 15.1nm on STD-11 die steel.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.374-375
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• 2006

The purpose of this paper is to investigate the propriety of biodegradable polymer pad in spite of exchanging from existing polyurethane pad used in CMP(Chemical Mechanical Planarization). Poli 400 of G&P Technology for CMP and Ellipsometer of Rudolph AutoEL-III for measurement were used in this experiment. From this experiment, it is proven that the biodegradable polymer pad is sufficiently suitable in CMP process. Therefore, it is expected that, by using the biodegrable pad CMP manufacturing process, and will be decreased. Especially, wafer scratch can be decreased.

• Journal of the Semiconductor & Display Technology
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• v.12 no.1
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• pp.61-65
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• 2013

We investigated the wearable dynamics of diamond spherical abrasive during the substrate surface polishing under the pad compression via classical molecular dynamics modeling. We performed three-dimensional molecular dynamics simulations using the Morse potential functions for the copper substrate and the Tersoff potential function for the diamond abrasive. The pad hardness had a big impact on the wearable dynamics of the abrasive. The moving speed of the abrasive decreased with increasing hardness of the pad. As the hardness decreased, the abrasive was indented into the pad and then the sliding motion of the abrasive was increased. So the pad hardness was greatly influenced on the slide-to-roll ratio as well as the wearable rate.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.7
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• pp.569-573
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• 2012

We investigated the speed change of the diamond spherical abrasive during the substrate surface polishing under the pad compression by using classical molecular dynamics modeling. We performed three-dimensional molecular dynamics simulations using the Morse potential functions for the copper substrate and the Tersoff potential function for the diamond abrasive. As the compressive pressure increased, the indented depth of the diamond abrasive increased and then, the speed of the diamond abrasive along the direction of the pad moving was decreased. Molecular simulation result such as the abrasive speed decreasing due to the pad pressure increasing gave important information for the chemical mechanical polishing including the mechanical removal rate with both the pad speed and the pad compressive pressure.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1816-1821
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• 2003

The sapphire wafer for blue light emitting device was manufactured by the implementation of the chemical and mechanical polishing process. The surface polishing of crystalline sapphire wafer was characterized by zeta potential measurement. The reduction process with the alkali slurry provides the surface chemical reaction with sapphire atoms. The poly-urethane pad also provides the frictional force to take out the chemically-reacted surface layers. The surface roughness was measured by the atomic force microscope and the crystalline quality was characterized by the double crystal X -ray diffraction analysis.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.4
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• pp.303-307
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• 2007

This paper investigated the effect of the pad buffing process on the material removal characteristics and pad stabilization during silicon chemical mechanical polishing. The pads surface were controlled by the buffing process using a buffer made by the sandpaper. The buffing process is based on abrasive machining by using a high speed sandpaper. The controlled pad by the buffing process show less deformation deviation and stable material removal rate during the CMP process. In addition, the controlled pad ensure better uniformity of removal rate than comparative pads. As a result of monitoring, the controlled pad by the buffing process demonstrated constant and stable friction force signals from initial polishing stage. Therefore, the tufting process could control the pad surface to be uniform and improve the performance of the polishing pad.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.3 s.234
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• pp.432-438
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• 2005

CMP characteristics such as material removal rate and edge effect were measured and investigated in accordance with pad grooving effect, groove width, depth and pitch. GSQ (Groove Stiffness Quotient) and GFQ (Groove Flow Quotient) were proposed to estimate pad grooving characteristics. GSQ is defined as groove depth(D) divided by pad thickness(T) and GFQ is defined as groove width(W) divided by groove pitch(P). As GFQ value increased, material removal rate increased some point but gradually saturated. It seems that material removal rate is not affected by each parameter respectively but by interaction of these parameters such as groove dimensions. In addition, an increase in GFQ and GSQ causes edge effect to be improved. Because, pad stiffness decreases as GSQ and GFQ increase. In conclusion, groove influences relative pad stiffness although original mechanical properties of pad are unchanged by grooving. Also, it affects the flow of slurry that has an effect on the lubrication regime and polishing results. The change of groove dimensions has influence on pad stiffness and slurry flow, so that polishing results such as removal rate and edge effect become changed.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.3 s.96
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• pp.84-90
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• 1999

The finishing process for dies and molds is directly related to finished surface quality, but many parts of process depend on human labor which needs much time and value. So automatic finishing machine has been produced for dies and molds, and applied widely for finishing process. Conventionally finishing machine has applied resin bonded finishing pad as a tool, but the removal ability of pad decreases greatly as finishing process goes on. In the finishing mechanism for dies and molds, finishing process is affected severely by cutting process, so can be divided into removing cusp and smoothing surface process. So, this study investigated the application of cast iron bonded diamond pellet for press dies, which is considered to have better characteristics than the other metal bonded pellets. The finishing characteristics were compared the between finishing pellet and pad. And finishing performance was appraised as the several cutting surfaces.

• Proceedings of the Korean Fiber Society Conference
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• 2001.10a
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• pp.401-402
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• 2001

Polishing pads were widely used industry and domestic needs such as finishing processing, surface cleaning. Especially, it is necessary to require inherent luster of metal. The spot on metal surface polishing and lifetime were depended on properties of constituted fiber in polishing pads. (omitted)

• Journal of the Korean Society for Railway
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• v.18 no.6
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• pp.578-585
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• 2015

Track elastic components can be technically and economically efficient when integrated well into track superstructure of a railway network. In such cases, the elastic rail pad is larger than a 800m radius curve provides smooth rail branching and allows for high-speed operation ($V{\geq}160km/h$). High track resistance causes the tamping intervals to stand out because the constantly increasing share of the sleeper pad further extends the increase of the tamping interval and the long grinding period; the engineering and construction of the small curve radius track provides some measures for reducing the solid sounds. Installation of elastic mats under the ballast can have a good effect, particularly in the context of protection against dust during construction or extensive renovation measures when laying new lines. However, such a process requires special attention and proper installation.