• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.11a
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• pp.263-268
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• 1999

Langasite, a new piezoelectric material was polished by CMP(chemical mechanical polishing). To enhance the polishing rate, alumina abrasives were added to commercial ILD1300 slurry which contains silica abrasive. The effect of added alumina 0 the silica slurry on the polishing rate and damage of langasite was investigated, Experimental results show that the polishing rate and roughness increases with increasing added alumina particle size, Crystallinity of the langasite is also lowered by alumina addition.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.3
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• pp.219-225
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• 2005

To investigate the effects of slurry temperature on the chemical mechanical polishing(CMP) performance of oxide film with silica and ceria slurries, we have studied slurry properties as a function of different slurry temperature. Also, the effects of each input parameter of slurry on the oxide CMP characteristics were investigated. The pH showed a slight tendency of decrease, the conductivity in slurries showed an increased tendency, the mean particle size in slurry decreased, and the zeta potential of slurry decreased with temperature. The removal rates significantly increased and maintained at the specific levels over 4$0^{\circ}C$. The better surface morphology of oxide films could be obtained at 40 $^{\circ}C$ of silica slurry and at 90 $^{\circ}C$ of ceria slurry. It is found that the CMP performance of oxide film could be significantly improved or controlled by change of slurry temperature.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.8
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• pp.134-140
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• 2002

Chemical mechanical polishing of aluminum and photoresist using colloidal silica-based slurry was experimented. The effects of slurry pH, silica concentration, and oxidizer ($H_2O_2$) concentration on surface roughness and removal rate were studied. The optimum slurry conditions for reduction of micro-scratch were investigated. The optimum chemical mechanical polishing with the colloidal silica-based slurry was compared with conventional chemical mechanical polishing with alumina-based slurry. Chemical mechanical polishing of the aluminum with the colloidal silica-based slurry showed improved result but chemical mechanical polishing of the photoresist did not. The improved result was comparative with that of chemical mechanical polishing with filtered alumina-based slurry which one of desirable methods to reduce the micro-scratch.

• Journal of the Korean Ceramic Society
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• v.44 no.2 s.297
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• pp.98-102
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• 2007

The stability of slurry and removal rate during recycling of colloidal silica slurry was evaluated in silicon wafer polishing. The particle size distribution, pH, and zeta potential were measured to investigate the stability of colloidal silica. Large particles appeared as recycling time increased while average size of slurry did not change. Large particles were identified by EDS(energy dispersive spectrometer) as foreign substances from pad or abraded silicon flakes during polishing. As the recycling time increased, pH of slurry decreased and removal rate of silicon reduced but zeta potential decreased inversely. Hence, it could be mentioned that decrease of removal rate is related to consumption of $OH^-$ ions during recycling. Attention should be given to the control of pH of slurry during polishing.

• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.85-86
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• 2006

Chemical mechanical polishing (CMP) technology has been widely used for global planarization of multi-level interconnection for ULSI applications. However, the cost of ownership and cost of consumables arc relatively high because of expensive slurry. In this paper, in order to save the costs of slurry, the original silica slurry was diluted by de-ionized water (DIW). And then, $ZrO_2$, abrasives were added in the diluted silica slurry (DSS) in order to promote the mechanical force of diluted slurry. We have also investigate the possibility of mixed abrasive slurry (MAS) for the oxide CMP application.

• 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.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.11
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• pp.551-555
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• 2004

In this paper, in order to reduce the high COO (cost of ownership) and COC (cost of consumables), we have collected the silica abrasive powders by filtering method after subsequent CMP (chemical mechanical polishing) process for the purpose of abrasives recycling. And then, we have studied the possibility of recycle of reused silica abrasive through the analysis of particle size distribution and FE-SEM (field emission-scanning electron microscope) measurements of abrasive powders. It was 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 rate of removal and good planarity with commercial products. Consequently we can expect the saving of high cost slurry.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.129-131
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• 2004

전 세계적으로 반도체 연마제용으로 silica를 많이 사용하고 있으며, 주로 fumed silica 및 colloidal silica로 구분되어진다. 반도체 연마제로서의 가장 중요한 요소는 연마율, defect 및 uniformity 등이 있으며, 현재 defect 및 uniformity는 많은 연구개발을 통하여 증진되었지만 반도체 생산량과 직접 관련된 연마율을 증가시키는 기술은 화학약품 및 slurry의 농도 증가로만 가능하다. 이에 연마제의 전반적인 기능을 상승시켜 기존보다 연마율은 높이고, 결함율을 낮추며, 120nm 이상의 입자크기를 제조하여도 근일한 입도 분포도를 나타내어주고, 장기간 안정하게 사용가능하고, 친환경적인 반도체 연마제를 개발하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05d
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• pp.109-112
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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 reused silica slurry in order to reduce the costs of CMP slurry. Also, we have collected the silica abrasive powders by filtering after subsequent CMP process for the purpose of abrasive particle recycling. And then, 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.

• Applied Chemistry for Engineering
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• v.10 no.7
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• pp.1073-1078
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• 1999

The objectives of this study are to examine the applicability of waste slurry from soda ash manufacturing industries as a coagulant for the treatment of wastewater containing fine silica particles, and to reduce the cost of wastewater treatment containing silica. Acceptable water quality can be obtained with a little dosing of waste slurry by gelation before the coagulation process so it could be concluded that the waste slurry from soda ash can be used as a coagulant. Based on the results of experiments, the optimum pH of gelation for silica in wastewater was around five and the treatment process with the gelation of silica could reduce the chemical dosage and waste sludge after coagulation. Dewatering and settling characteristics of the floc after coagulation with the waste slurry are better than those of the floc after coagulation with the lime milk only.