• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.05a
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• pp.272-278
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• 2002

Recently, STI(Shallow Trench Isolation) process has attracted attention for high density of semiconductor device as a essential isolation technology. In this paper, the effect of pattern density, trench width and selectivity of slurry on dishing in STI CMP process was investigated by using specially designed isolation pattern. As trench width increased, the dishing tends to increase. At $20{\mu}m$ pattern size, the dishing was decreased with increasing pattern density Low selectivity slurry shows less dishing at over $160{\mu}m$ trench width, whereas high selectivity slurry shows less dishing at below $160{\mu}m$ trench width.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.4
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• pp.321-326
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• 2005

Chemical mechanical polishing(CMP) process is essential technology to be applied to manufacturing the dielectric layer and metal line in semiconductor devices. It has been known that overpolishing in CMP depends on pattern selectivity as a function of density and pitch, and use of fixed abrasive pad(FAP) is one method which can improve the pattern selectivity. Thus, dishing & erosion defects can be reduced. This paper introduces the manufacturing technique of FAP using hydrophilic polymers with swelling characteristic in water and explains the self-conditioning phenomenon. When applied to tungsten blanket wafers, the FAP resulted in appropriate performance in point of uniformity, material selectivity and roughness. Especially, reduced dishing and erosion was observed in CMP of tungsten pattern wafer with the proposed FAP.

• Journal of Sensor Science and Technology
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• v.20 no.6
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• pp.428-433
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• 2011

We report on the building of a micro sensor array based on typical semiconductor fabrication processes aimed at monitoring selectively a specific gas in ambient of other gases. Chemical sensors can be applied for an electronic nose and/or robots using this technique. Microsensor array was fabricated on the same chip using 0.6${\mu}m$ CMOS technology, and unique gas sensing patterns were obtained by principal component analysis from the array. $SnO_2$/Pt sensor for CO gas showed a high selectivity to buthane gas and humidity. $SnO_2$ sensor for hydrogen gas, however, showed a low selectivity to CO and buthane gas. We can obtain more distinguishable patterns that provide the small sensing deviation(the high seletivity) toward a given analyte in the response space than in the chemical space through the specific parameterization of raw data for chemical image formation.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.465-468
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• 1998

For porous silicon layer to be used as active layer in various devices, it is necessary to be formed locally along with a designed pattern on the wafer. However, there is still no suitable masking layer to withstand against the high concentration of HF for a time of some minutes up to some hours during the anodic process effectively. In this work, we investigated the property of selectivity between p$^{+}$ and n layers to form localized porous silicon even without a mask by the difference of the anodic I-V characteristics on the doping level and doping type. The width of the pattern made in the sample was 2mm, and the formed porous silicon layer was observed by SEM to see the morphology on the cross section below the surface. As the results, it was found that the selectivity was reasonable for the pattern size over 100.mu.m.m.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04b
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• pp.35-38
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• 2000

In this study, the rise throughput and the stability in fabrication of device can be obtained by applying of CMP process to STI structure in 0.l8um semiconductor device. Through reverse moat pattern process, reduced moat density at high moat density, STI CMP process with low selectivity could be to fit polish uniformity between low moat density and high moat density. Because this reason, in-situ motor current end point detection method is not fit to the current EPD technology with the reverse moat pattern. But we use HSS without reverse moat pattern on STI CMP and take end point current sensing signal.[1] To analyze sensing signal and test extracted signal, we can to adjust wafer difference within $110{\AA}$.

• Journal of the Korean Ceramic Society
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• v.40 no.11
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• pp.1073-1077
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• 2003

The Sn $O_2$-based gas sensors can detect inflammable and toxic gases of low concentration by the modulation of surface resistance, but they lack in selectivity on the whole. To give selectivity to the Sn $O_2$-based gas sensors, studies on the sensing mechanism, selective gas sensing materials and signal processing techniques are demanded. Ethanol (C$_2$ $H_{5}$OH) and acetonitrile ($CH_3$CN) were confirmed to undergo catalytic oxidation on Sn $O_2$ by gas chromatography. PdCl$_2$-doped Sn $O_2$ showed excellent sensitivity to ethanol and acetonitrile, while La$_2$ $O_3$-doped Sn $O_2$ showed excellent sensitivity to ethanol, but poor sensitivity to acetonitrile. Using these two sensors and pattern recognition, the selectivity to acetonitrile is greatly enhanced. The minimum detection level of acetonitrile was 15 ppm in air and 20 to 100 ppm when exposed to interfering gases together with acetonitrile.

• Archives of Pharmacal Research
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• v.21 no.4
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• pp.385-390
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• 1998

Adozelesin and carzelesin are synthetic analogues of the extremely potent antitumor antibiotic CC-1065, which alkylates N3 of adenine in a consensus sequence $5^1$-(A/T)(A/T)$A^*$ ($A^*$ is the site of alkylation). We have investigated the DNA sequence selectivity of adozelesin and carzelesin by thermally ind ced DNA strand cleavage assay using radiolabeled restriction DNA fragments. An analysis of alkylation patterns shows that the consensus sequences for carzelesin and adozelesin have been found to be $5^1$-(A/T)(A/T)$A^*$ and $5^1$-(A/F)(G/C)(A/T)$A^*$. A new consensus sequence, $5^1$-(A/T)(A/T)$CA^*$, has been observed to display an additional alkylation site for adozelesin but not for carzelesin. These results indicate that the pattern of sequence selectivity induced by carzelesin is similar but not identical to those induced by adozelosin.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.2 no.4
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• pp.17-24
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• 2003

Chemical mechanical polishing(CMP) has been applied for planarization of topography after patterning process in semiconductor fabrication process. Tungsten CMP is necessary to build up interconnects of semiconductor device. But the tungsten dishing and the oxide erosion defects appear at end-point during tungsten CMP. It has been known that the generation of dishing and erosion is based on the over-polishing time, which is determined by pattern selectivity. Fixed abrasive pad takes advantage of decreasing the defects resulting flam reducing pattern selectivity because of the lower abrasive concentration. The manufacturing technique of fixed abrasive pad using hydrophilic polymers is introduced in this paper. For application to tungsten CMP, chemicals composed of oxidizer, catalyst, and acid were developed. In comparison of the general pad and slurry for tungsten CMP, the fixed abrasive pad and the chemicals resulted in appropriate performance in point of removal rate, uniformity, material selectivity and roughness.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.140-143
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• 2004

Chemical mechanical polishing(CMP) is essential technology to secure the depth of focus through the global planarization of wafer. But a variety of defects such as contamination, scratch, dishing, erosion and corrosion are occurred during CMP. Especially, dishing and erosion defects increase the resistance because they decrease the interconnect section area, and ultimately reduce the life time of the semiconductor. Due to this dishing and erosion must be prohibited. The pattern density and size in chip have a significant influence on dishing and erosion occurred over-polishing. Decreasing of abrasive concentration results in advanced pattern selectivity which can lead the uniform removal in chip and decrease of over-polishing. The fixed abrasive pad was applied and tested to reduce dishing and erosion in this paper. Consequently, reduced dishing and erosion was observed in CMP of tungsten pattern wafer with proposed fixed abrasive pad and chemicals.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.2
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• pp.38-45
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• 2005

Chemical mechanical polishing(CMP) has been widely accepted for the planarization of multi-layer structures in semiconductor fabrication. But a variety of defects such as abrasive contamination, scratch, dishing, erosion and corrosion are occurred during CMP. Especially, dishing and erosion defects increase the metal resistance because they decrease the interconnect section area, and ultimately reduce the lift time of the semiconductor. Due to this reason dishing and erosion must be prohibited. The pattern density and size in chip have a significant influence on dishing and erosion occurred by over-polishing. The fixed abrasive pad(FAP) was applied and tested to reduce dishing and erosion in this paper. The abrasive concentration decrease of FAP results in advanced pattern selectivity which can lead the uniform removal in chip and declining over-polishing. Consequently, reduced dishing and erosion was observed in CMP of tungsten pattern wafer with proposed FAP and chemicals.