• Journal of the Korean Society for Precision Engineering
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• v.22 no.2
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• pp.46-52
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• 2005

The sapphire wafer was polished by the implementation of the surface machining technology based on nano-tribology, The removal process has been performed by grinding, lapping and chemical-mechanical polishing. For the chemical mechanical polishing process, the chemical reaction between the slurry and sapphire wafer was investigated in terms of the change of Zeta-potential between two materials. The Zeta-potential was -4.98 mV without the slurry in deionized water and was -37.05 mV for the slurry solution. By including the slurry into the deionized water the Zeta-potential -29.73 mV, indicating that the surface atoms of sapphire become more repulsive to be easy to separate. The average roughness of the polished surface of sapphire wafer was ranged to 1∼4$\AA$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.33-36
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• 2001

Chemical mechanical polishing(CMP) process has been widely used to planarize dielectric layers, which can be applied to the integrated circuits for deep sub-micron technology. The rise throughput and the stability in the device fabrication can be obtained by applying of CMP process to STI structure in 0.18$\mu\textrm{m}$ m semiconductor device. The reverse moat process has been added to employ in of each thin films in STI-CMP was not equal, hence the devices must to be effected, that is, the damage was occurred in the device area for the case of excessive CMP process and the nitride film was remained on the device area for the case of insufficient CMP process, and than, these defects affect the device characteristics. Also, we studied the High Selectivity Slurry(HSS) to perform global planarization without reverse moat step.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.11
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• pp.939-945
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• 2002

The rise throughput and the stability in the device fabrication can be obtained by applying chemical mechanical polishing (CMP) process in 0.18 $\mu\textrm{m}$ semiconductor device. However, it still has various problems due to the CMP equipment. Especially, among the CMP components, process variables are very important parameters in determining the removal rate and non-uniformity. In this paper, we studied the DOE (design of experiment) method in order to get the optimized CMP equipment variables. Various process parameters, such as table and head speed, slurry flow rate and down force, have investigated in the viewpoint of removal rate and non-uniformity. Through the above DOE results, we could set-up the optimal CMP process parameters.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.4
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• pp.486-492
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• 2004

CMP (Chemical mechanical polishing) is inevitable process to overcome $0.2{\mu}m$ wire thickness in semiconductor industry. In this study, effect of pressure to separate used CMP slurry into solid and liquid for recycle and reuse by ultrafiltration was investigated. Also, water quality after the ultrafiltration such as turbidity and TDS was evaluated. The material of membrane used in the study was PVDF. The used CMP contained 0.5% of solid content and then concentrated up to 18% by weight. The used CMP can not be concentrated higher than 18% because of viscosity and abrasion of pump. The tested feed pressures were 22.1, 29.4 and 36.8 psi. The results have shown that operating at 36.8 psi has advantages on operation time and total flux. The specific flux showed some variation at 1 to 15 of concentration factor but no difference after 15 of concentration factor. Mass balance of solid at initial stage of the operation showed some unbalance because of deposition of solid on the membrane, which was main reason to reduce flux. Turbidity was very stable at lower than 0.2NTU for 22.1 and 36.8 psi of feed pressure.

• 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.

• Clean Technology
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• v.7 no.1
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• pp.27-34
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• 2001

The waste slurry generated from CMP process contains particulate and heavy metals. It is hard to treat the waste slurry by conventional treatment method because the particulates in the waste are too fine to be easily separated the solid from the waste for the purpose of water recycling. The investigation was focused on finding the optimum condition of coagulation with two different coagulants. When the solid content in the waste slurry solution was 0.1wt%, the optimal ranges of pH and PACl concentration were 4~6 and 20~50 mg/L, respectively. When the solid content was increased to 0.5wt%, the optimal condition was 4~5 for pH and 50~100 mg/L for PACl concentration.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.239-242
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• 2004

We investigated the nanotopography impact on the post-chemical mechanical polishing (post-CMP) oxide thickness deviation(OTD) of ceria slurry with a surfactant. Not only the surfactant but also the slurry abrasive size influenced the nanotopography impact. The magnitude of the post-CMP OTD increased with adding the surfactant in the case of smaller abrasives, but it did not increase in the case of larger abrasives, while the magnitudes of the nanotopography heights are all similar. We created a one-dimensional numercal simulation of the nanotopography impact by taking account of the non-Prestonian behavior of the slurry, and good agreement with experiment results was obtained.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.339-342
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• 2003

The corrosion characteristics of Copper by oxidizers in Cu CMP slurry has been investigated. Key experimental variables that has been investigate are the corrosion rate by different oxidizers containing slurry of Cu CMP. Oxidizers in Cu CMP slurry reacts with Cu surfaces to raise the oxidation state of the metal via a reduction-oxidation reaction, resulting in either dissolution of the Cu or the formation of Ta surface film on the metal.[1] When Cu films were corroded adding each oxidizer, corrosion rate increased as much as higher Icorrosion. The corrosion rate of Cu was the largest as added $(NH_4)_2S_2O_8$. The higher content of Urea Hydrogen peroxide was, the higher corrosion rate was measured. Putting in tartaric acid as complexing agent, the corrosion rates of the compounds(Urea hydrogen peroxide+$H_2O_2$) are uniformly. As a result of Cu corrosion by $Cu(NO_3)_2$, the high corrosion rate was determined by even small amounts of $Cu(NO_3)_2$. Consequently, this can be explained by assuming that corrosion by oxidizers has primary effects on the removal rate of Cu and the proper oxidizer needs to be chosen in accordance with relationship of each slurry agent.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.382-385
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• 2003

Chemical mechanical polishing(CMP) is an essential process in the production of copper-based chips. On this work, the stability of Hydrogen Peroxide($H_2O_2$) as oxidizer of Cu CMP slurry has been investigated. $H_2O_2$ is known as the most common oxidizer in Cu CMP slurry. Copper slowly dissolves in $H_2O_2$ solutions and the interaction of $H_2O_2$ with copper surface had been studied in the literature. Because hydrogen peroxide is a weak acid in aqueous solutions, a passivation-type slurry chemistry could be achieved only with pH buffered solution.[1] Moreover, $H_2O_2$ is so unstable that its stabilization is needed using as oxidizer. As adding KOH as pH buffering agent, stability of $H_2O_2$ decreased. However, stability went up with putting in small amount of BTA as film forming agent. There was no difference of $H_2O_2$ stability between KOH and TMAH at same pH. On the other hand, $H_2O_2$ dispersion of TMAH is lower than that of KOH. Furthermore, adding $H_2O_2$ in slurry in advance of bead milling lead to better stability than adding after bead milling. Generally, various solutions of phosphoric acids result in a higher stability. Using Alumina C as abrasive was good at stabilizing for $H_2O_2$; moreover, better stability was gotten by adding $H_3PO_4$.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.443-444
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• 2002

The uniformity of field oxide is critical to isolation property of device in STI, so the control of field oxide thickness in STI-CMP becomes enormously important. The loss of field oxide in shallow trench isolation comes mainly from dishing and erosion in STI-CMP. In this paper, the effect of slurries on the dishing was investigated with both blanket and patterned wafers were selected to measure the removal rate, selectivity and dishing amount. Dishing was a strong function of pattern spacing and types of slurries. Dishing was significantly decreased with decreasing pattern spacing for both slurries. Significantly lower dishing with ceria based slurry than with silica based slurry were achieved when narrow pattern spacing were used. Possible dishing mechanism with two different slurries were discussed based on the observed experimental results.