• Proceedings of the IEEK Conference
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• 2001.10a
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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.

• Particle and aerosol research
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• v.9 no.4
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• pp.261-269
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• 2013

The chemical mechanical polishing (CMP) process is widely used in semiconductor manufacturing process for planarization of various materials and structures. Point-of-use (POU) filters are used in most of the CMP processes in order to reduce the unwanted micro-scratches which may result in defects. The performance of the POU filter is depends on type and size of the abrasives used during cleaning process. For this reason, there is a need to evaluate POU filters for their filtration efficiency (FE) with different types of abrasives. In this study, we developed filter test system to evaluate the FE of POU using ceria and silica abrasives (slurry). The POU filter is roll type capsule filter with retention size of 0.2 ${\mu}m$. Two POU filters of different make are evaluated for FE. We observed that both POU filters show similar filtration efficiency for silica and ceria slurry. Results reveal that the ceria slurry and the colloidal silica particle are removed not only by mechanical way but also hydrodynamic and electrostatic interaction way.

• Tribology and Lubricants
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• v.37 no.6
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• pp.208-212
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• 2021

Chemical mechanical polishing (CMP) is a key technology used for the global planarization of thin films in semiconductor production and smoothing the surface of substrate materials. CMP is a type of hybrid process using a material removal mechanism that forms a chemically reacted layer on the surface of a material owing to chemical elements included in a slurry and mechanically removes the chemically reacted layer using abrasive particles. Sapphire is known as a material that requires considerable time to remove materials through CMP owing to its high hardness and chemical stability. This study introduces a technology using electrolytic ionization and ultraviolet (UV) light in sapphire CMP and compares it with the existing CMP method from the perspective of the material removal rate (MRR). The technology proposed in the study experimentally confirms that the MRR of sapphire CMP can be increased by approximately 29.9, which is judged as a result of the generation of hydroxyl radicals (·OH) in the slurry. In the future, studies from various perspectives, such as the material removal mechanism and surface chemical reaction analysis of CMP technology using electrolytic ionization and UV, are required, and a tribological approach is also required to understand the mechanical removal of chemically reacted layers.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.9 s.240
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• pp.1276-1281
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• 2005

Compound semiconductors are the semiconductors composed of more than two chemical elements. Lithium Tantalate$K_I$ wafer is used for several optical devices, especially surface acoustic wave(SAW) device. Because of the lithography in SAW device process, $LiTaO_3$ polishing is needed. In this paper, the commercial slurries $(NALC02371^{TM},\; ILD1300^{TM},\;ceria slurry)$ used for chemical mechanical polishing(CMP) were tested, and the most suitable slurry was selected by measuring material removal rate and average centerline roughness$(R_a)$. From these result, it was proven that $ILD1300^{TM}$ was the most suitable slurry for $LiTaO_3$ wafer CMP due to the chemical reaction between solution in slurry and material.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.2
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• pp.156-161
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• 2004

We investigated the effects of oxidizer additive on the performance of Cu-CMP process using commonly used tungsten slurry. In order to compare the removal rate and non-uniformity as a function of oxidizer contents, we used alumina-based tungsten slurry and copper blanket wafers deposited by DC sputtering method. According to the CMP removal rates and particle size distribution, and the microstructures of surface layer by SEM image as a function or oxidizer contents were greatly influenced by the slurry chemical composition of oxidizers. The difference in removal rate and roughness of copper surface are believed to cause by modification in the mechanical behavior of $Al_2$O$_3$abrasive particles in CMP slurry.

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

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.46-49
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• 2003

Chemical mechanical polishing (CMP) is an essential dielectric planarization in multilayer microelectronic device fabrication. In the CMP process it is necessary to minimize the extent of surface defect formation while maintaining good planarity and optimal material removal rates. The polishing mechanism of W-CMP process has been reported as the repeated process of passive layer formation by oxidizer and abrasion action by slurry abrasives. Thus, it is important to understand the effect of oxidizer on W passivation layer, in order to obtain higher removal rate (RR) and very low non-uniformity (NU%) during W-CMP process. In this paper, we compared the effects of oxidizer or W-CMP process with three different kind of oxidizers with 5% hydrogen peroxide such as $Fe(NO_3)_3$, $H_2O_2$, and $KIO_3$. The difference in removal rate and roughness of W in stable and unstable slurries are believed to caused by modification in the mechanical behavior of $Al_3O_3$ particles in presence of surfactant stabilizing the slurry.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.1
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• pp.85-91
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• 2004

The sapphire wafers for blue light emitting devices were manufactured by the implementation of the surface machining technology based on micro-tribology. This process has been performed by chemical and mechanical polishing process. The sapphire crystalline wafers were characterized by double crystal X-ray diffraction. The sample quality of sapphire crystalline wafer at surfaces has a full width at half maximum of 89 arcsec. The surfaces of sapphire wafer were mechanically affected by residual stress during the polishing process. The wave pattern of optical interference of sapphire wafer implies higher abrasion rate in the edge of the wafer than its center from the Newton's ring.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.537-537
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• 2008

Copper (Cu) has been widely used for interconnection structure in intergrated circuits because of its properties such as a low resistance and high resistance to electromigration compared with aluminuim. Damascene processing for the interconnection structure utilizes 2-steps chemical mechanical polishing(CMP). After polishing, the removal of abrasive particles on the surfaces becomes as important as the polishing process. In the paper, buffing process for the removal of colloidal silica from polished Cu wafer was proposed and demonstrated.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.37-38
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• 2013