• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.59-60
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• 2006

The slurry stability and removal rate during recycling of slurry in silicon wafer polishing was studied. Average abrasive size of slurry was not changed with recycling time, however, large particles appeared as recycling time increased. Large particles were related foreign substances from pad or abraded silicon flakes during polishing. The removal rate as well as pH of slurry was decreased as recycling time increased. It suggests that the consumption of OH ions during recycling is the main cause of decrease of removal rate. Therefore, it is important to control pH of slurry to obtain optimum removal rate during polishing.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.6
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• pp.291-296
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• 2006

In this study, the sputtered BTO film was polished by CMP process with the self-developed $BaTiO_3$- and $TiO_2$-mixed abrasives slurries (MAS), respectively. The removal rate of BTO ($BaTiO_3$) thin film using the $BaTiO_3$-mixed abrasive slurry (BTO-MAS) was higher than that using the $TiO_2$-mixed abrasives slurry ($TiO_2$-MAS) in the same concentrations. The maximum removal rate of BTO thin film was 848 nm/min with an addition of $BaTiO_3$ abrasive at the concentration of 3 wt%. The sufficient within-wafer non-uniformity (WIWNU%) below 5% was obtained in each abrsive at all concentrations. The surface morphology of polished BTO thin film was investigated by atomic force microscopy (AFM).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.118-118
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• 2008

The oxide CMP has been applied to interlayer dielectric(ILD) and shallow trench isolation (STI) in chip fabrication. Recently the slurry used in oxide CMP being changed from silica slurry to ceria (cerium dioxide) slurry particularly in STI CMP, because the material selectivity of ceria slurry is better than material selectivity of silica slurry. Moreover, the ceria slurry has good a planarization efficiency, compared with silica slurry. However ceria abrasives make a material removal rate too high at the region of wafer center. Then we focuses on why profile of material removal rate is convex. The material removal rate sharply increased to 3216 $\AA$/min by $4^{th}$ run without conditioning. After $4^{th}$ run, material removal rate converged. Furthermore, profile became more convex during 12 run. And average material removal rate decreased when conditioning process is added to end of CMP process. This is due to polishing mechanism of ceria. Then the ceria abrasive remains at the pad, in particular remains more at wafer center contacted region of pad. The field emission scanning electron microscopy (FE-SEM) images showed that the pad sample in the wafer center region has a more ceria abrasive than in wafer outer region. The energy dispersive X-ray spectrometer (EDX) verified the result that ceria abrasive is deposited and more at the region of wafer center. Therefore, this result may be expected as ceria abrasives on pad surface causing the convex profile of material removal rate.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.35-36
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• 2012

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.39-42
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• 2002

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. The post-CMP thickness and within-wafer non-uniformity(WIWNU) were measured as a function of different slurry composition. As a 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 the 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 saving of high costs of slurry.

• 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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.378-379
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• 2006

CMP(chemical mechanical polishing) process has been attracted as an essential technology of multi-level interconnection. However, the COO(cost of ownership) is very high, because of high consumable cost. Especially, among the consumables, slurry dominates more than 40 %. So, we focused how to reduce the consumption of raw slurry. In this paper, $ZrO_2$, $CeO_2$, and $MnO_2$ abrasives were added de-ionized water (DIW) and pH control as a function of KOH contents. We have investigate the possibility of new abrasive for the oxide CMP application.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.3 no.1
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• pp.38-44
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• 2004

An internal finishing process by the application of magnetic abrasive machining has been developed as a new technology to obtain a fine inner surface of non-ferromagnetic pipe. In this paper, an abrasive slurry circulation system was designed and manufactured. As a result, it was found that a fine inner surface of pipe was available by the use of these machining methods. The basic machining characteristics of pin-type magnetic tools were analyzed experimentally. In addition, the experimental results show that pin-type magnetic tools have more machining efficiency than Iron particles as magnetic tools.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.40-41
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• 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
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• v.15 no.10
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• pp.851-857
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• 2002

CMP(chemical mechanical polishing) process has been attracted as an essential technology of multi~level interconnection. However, the COO(cost of ownership) is very high, because of high consumable cost. Especially, among the consumables, slurry dominates more than 40%. So, we focused how to reduce the consumption of raw slurry In this paper, we presented the pH changes of diluted slurry and pH control as a function of KOH contents. Also, the removal rates of slurry with different dilution ratio were investigated. Finally, the CMP characteristics were discussed as a function of silica (SiO$_2$) abrasive contents.