• Journal of Power System Engineering
• /
• v.10 no.1
• /
• pp.46-51
• /
• 2006

Present study was investigated the effect of the particle of the counterface of unidirectional carbon fiber reinforced composite. The friction coefficient of composite and the specific wear rate different sliding velocity were measured for this materials. The friction track of counterface was observed by an optical microscope and scanning electron microscope. There were insignificant effects of the specific wear rate under lower Sic abrasive particle, however it showed high effect on $30{\mu}m$ abrasive particle size. There were significant effects of friction and wear behavior of the fiber direction under 0.3m/s sliding speed. Major failure mechanisms can be classified such as microfracture, plowing, microcutting, cutting and cracking.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.20 no.3
• /
• pp.274-279
• /
• 2011

In this study, new abrasives that were composed of iron powder and carbon nanotube (CNT) particle were attempted to be abrasives for magnetic abrasive polishing. Because the CNT particles itself are very small ones with high hardness and magnetic strength, these properties are effective for magnetic abrasive polishing of nonmagnetic materials. As an experimental result for evaluating the machining characteristics in magnetic abrasive polishing, the CNT particles showed better performance than the conventional abrasives such as Fe and CBN powder.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.07a
• /
• pp.50-53
• /
• 2003

CMP (chemical mechanical polishing) process remained to solve several problems in deep sub-micron integrated circuit manufacturing process. especially consumables (polishing pad, backing film, slurry, pad conditioner), one of the most important components in the CMP system is the slurry. Among the composition of slurries (buffer solution, bulk solution, abrasive particle, oxidizer, inhibitor, suspension, antifoaming agent, dispersion agent), the abrasive particles are important in determining polish rate and planarization ability of a CMP process. However, the cost of abrasives is still very high. So, in order to reduce the high COO (cost of ownership) and COC (cost of consumables) in this paper, we have collected the silica abrasive powders by filtering after subsequent CMP process for the purpose of abrasive particle recycling. And then, we have studied the possibility of recycle of reused silica abrasive through the analysis of particle size and hardness. Also, we annealed the collected abrasive powders to promote the mechanical strength of reduced abrasion force. Finally, we compared the CMP characteristics between self-developed KOH-based silica abrasive slurry and original slurry. As our experimental results, we obtained the comparable removal rate and good planarity with commercial products. Consequently, we can expect the saving of high cost slurry.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.21 no.6
• /
• pp.74-80
• /
• 2022

The surface status of a workpiece determines its functionality, product quality, and manufacturing costs. Thus, several finishing technologies have been widely investigated and applied to improve surface characteristics. In this study, rotational electro-magnetic abrasive finishing (REMAF) was suggested as a non-contact finishing process to achieve high geometric precision. To verify the effects of the REMAF process on burr removal on the surface of Al6061, experiments were conducted using the Taguchi method. Based on the experimental results analyzed by the S/N ratio and ANOVA, the optimal conditions were defined as A₃B₂C₃D₃ that corresponded to 1,800 rpm of rotational speed, 1.5 kg of abrasive particle weight, 0.7 mm of abrasive diameter, and 15 min of working time. In addition, the particle weight was a key attribute for deburring, whereas the working time was less effective.

• Tribology and Lubricants
• /
• v.25 no.6
• /
• pp.404-408
• /
• 2009

In this paper, the relationship between the material removal rate and the interfacial mechanical properties at particle-surface contact situation, which can be seen in an abrasive machining process using micro/nano-sized particles, was discussed. Friction and stiffnesses were measured experimentally on an atomic force microscope (AFM) by using colloidal probes which have a silica colloid particle in place of tip to simulate a particle-flat surface contact in an abrasive machining process. From the experimental investigation and theoretical contact analysis, the interfacial contact properties such as lateral stiffness of contact, friction, the material removal rate were presented with respect to some of material surfaces and the relationship between the properties as well.

• Tribology and Lubricants
• /
• v.35 no.5
• /
• pp.274-285
• /
• 2019

Chemical mechanical polishing (CMP), which is a material removal process involving chemical surface reactions and mechanical abrasive action, is an essential manufacturing process for obtaining high-quality semiconductor surfaces with ultrahigh precision features. Recent rapid growth in the industries of digital devices and semiconductors has accelerated the demands for processing of various substrate and film materials. In addition, to solve many issues and challenges related to high integration such as micro-defects, non-uniformity, and post-process cleaning, it has become increasingly necessary to approach and understand the processing mechanisms for various substrate materials and abrasive particle behaviors from a tribological point of view. Based on these backgrounds, we review recent CMP R&D trends in this study. We examine experimental and analytical studies with a focus on substrate materials and abrasive particles. For the reduction of micro-scratch generation, understanding the correlation between friction and the generation mechanism by abrasive particle behaviors is critical. Furthermore, the contact stiffness at the wafer-particle (slurry)-pad interface should be carefully considered. Regarding substrate materials, recent research trends and technologies have been introduced that focus on sapphire (${\alpha}$-alumina, $Al_2O_3$), silicon carbide (SiC), and gallium nitride (GaN), which are used for organic light emitting devices. High-speed processing technology that does not generate surface defects should be developed for low-cost production of various substrates. For this purpose, effective methods for reducing and removing surface residues and deformed layers should be explored through tribological approaches. Finally, we present future challenges and issues related to the CMP process from a tribological perspective.

• Journal of Electrical Engineering and Technology
• /
• v.13 no.2
• /
• pp.886-891
• /
• 2018

Colloid silica using as abrasive for polishing sapphire has been extensively studied, which mechanism has also been deeply discussed. However, by the requirement of application enlargement and cost reduction, some new problems appear such as silica service life time, particle diameter mixing, etc. In this paper, several influences of colloid silica usage on sapphire CMP are examined. Results show particle diameter and concentration, pH value, service life time, particle diameter mixing heavily influence removal rate. Further analysis discloses there are two main effect aspects which are quantity of hydroxyl group, contact area for abrasive density stacking between abrasive and sapphire. Based on the discussions, a dynamic process of sapphire polishing is proposed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2005.07a
• /
• pp.40-41
• /
• 2005

In this study, we proposed CMP micro-scratches generated by contaminative particle which existed on the wafer surface prior to CMP process. The CMP micro-scratches are one of the slurry abrasive related damage. To reduce the micro-scratches, research efforts have been devoted to the optimization of slurry abrasive size distribution. In addition of slurry abrasive, it was found that contaminative particles also were major CMP micro-scratch source.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.22 no.2
• /
• pp.114-118
• /
• 2009

PVA (polyvinyl alcohol) brush cleaning method is a typical cleaning method for semiconductor cleaning process especially post-CMP cleaning. PVA brush contacts with the wafer surface and abrasive particle, generating the contact rotational torque of the brush, which is the removal mechanism. The brush rotational torque can overcome theoretically the adhesion force generated between the abrasive particle and wafer by zeta potential. However, after CMP (chemical mechanical polishing) process, many particles remained on the wafer because the brush was contaminated in previous post-CMP cleaning step. The abrasive particle on the brush redeposits to the wafer. The level of the brush contamination increased according to the cleaning run time. After cleaning the brush, the level of wafer contamination dramatically decreased. Therefore, the brush cleanliness effect on the cleaning performance and it is important for the brush to be maintained clearly.

• Transactions of Materials Processing
• /
• v.15 no.7 s.88
• /
• pp.518-523
• /
• 2006

Wet wire drawing of brass coated steel wire, used for tire reinforcement, is realized with Tungsten Carbide(WC) dies sintered with a cobalt(Co) binder. Dies wear represents an important limitation to the production process and cost savings. Several parameters, such as Co content, WC grain size of tungsten carbide, sintering conditions, and so on, affect on the wear of the drawing die. In this study, the effect of the diamond abrasive particle size on the life of the WC centered dies of the wet wire drawing was investigated. Wet wire drawing experiments were carried out on a wet wire drawing machine. From the experiments, the dies life, dies fracture, wire surface roughness, and wire breaks were investigated. From the results, it was found that the wear of the WC dies increased with the increase in the diamond abrasive particle size.