• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.20-23
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• 2004

As the integrated circuit device shrinks to the smaller dimension, the chemical mechanical polishing(CMP) process was required for the global planarization of inter-metal dielectric(IMD) layer with free-defect. However, as the IMD layer gets thinner, micro-scratches are becoming as major defects. Chemical-Mechanical polishing(CMP) of conductors is a key process in Damascene patterning of advanced interconnect structure. The effect of alternative commercial slurries pads, and post-CMP cleaning alternatives are discuss, with removal rate, scratch dentisty, surface roughness, dishing, erosion and particulate density used as performance metrics. Electroplated copper deposition is a mature process from a historical point of view, but a very young process from a CMP perspective. While copper electro deposition has been used and studied for decades, its application to Cu damascene wafer processing is only now gaining complete acceptance in the semiconductor industry. The polishing mechanism of Cu-CMP process has been reported as the repeated process of passive layer formation by oxidizer and abrasion action by slurry abrasives. however it is important to understand the effect of oxidizer on copper passivation layer in order to obtain higher removal rate and non-uniformity during Cu-CMP process. In this paper, we investigated the effects of oxidizer on Cu-CMP process regarding the additional volume of oxidizer.

• Journal of Life Science
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• v.15 no.6 s.73
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• pp.1034-1036
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• 2005

Chinese cabbage (Brassica campestris ssp. napus var. pekinensis Makino) seeds/seedlings were transformed via vacuum-infiltration with recombinant Agrobacterium tumefaciens LBA4404 cells. The agroinfiltration method was determined to be unsuccessful for Chinese cabbage transformation during the analysis of hepatitis B surface antigen expression by ELISA. However, treatment of sodium hypochlorite solution, prior to agroinfiltration, to pregerminated or germinating 1 day- or 2 days-old seeds was proven effectively to enhance transformation efficiency, suggesting that chemical wounding caused by sodium hypochlorite reaction might facilitate Agrobacterium infection and, therefore, transient gene expression in Chinese cabbage sprouts.

• Tribology and Lubricants
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• v.38 no.5
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• pp.222-226
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• 2022

Between diaphragms made of stainless steel (SUS), which is the main component of a hydrogen gas compressor, micro-slip occurs owing to repeated bending, resulting in scratches on the surface. The surface scratch of the compressor part is a problem with airtightness, which reduces the efficiency of the compressor; in severe cases, damage is a possibility. In this study, the changes in friction and wear characteristics due to the surface polishing of SUS and carbon-based solid lubricant films (graphene and CNT) were analyzed. Bare SUS, polished SUS, graphene film, and CNT film specimens were prepared. The surface roughness of the SUS was significantly reduced by surface polishing but increased by carbon-based solid lubricating films. In contrast, the friction coefficient maintained a similar value after surface polishing but was significantly reduced by the carbon-based solid lubricant films. In particular, the graphene film exhibited the lowest initial friction coefficient, while the CNT film exhibited the lowest overall average friction coefficient. Regarding the wear rate, polished SUS exhibited the lowest value, but the surface condition of the wear track showed that the carbon-based solid lubricating films were relatively less damaged. Although the wear rate measured was largely attributed to the solid lubricating film peeling off, the SUS surface under the film was considered protected.

• Journal of the Korean institute of surface engineering
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• v.57 no.3
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• pp.140-154
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• 2024

As the trend towards miniaturization in semiconductor integration process, the limitations of interconnection metals such as copper, tungsten have become apparent, prompting research into the emergence of new materials like cobalt and emphasizing the importance of studying the corresponding process conditions. During the chemical mechanical polishing (CMP) process, corrosion inhibitors are added to the slurry, forming passivation layers on the cobalt surface, thereby playing a crucial role in controlling the dissolution rate of the metal surface, enhancing both removal rate and selectivity. This review investigates the understanding of the cobalt polishing process and examines the characteristics and behavior of corrosion inhibitors, a type of slurry additive, on the cobalt surface. Among the corrosion inhibitors examined, benzotriazole (BTA), 1,2,4-triazole (TAZ), and potassium oleate (PO) all improved surface characteristics through their interaction with cobalt. These findings provide important guidelines for selecting corrosion inhibitors to optimize CMP processes for cobalt-based semiconductor materials. Future research should explore combinations of various corrosion inhibitors and the development of new compounds to further enhance the efficiency of semiconductor processes.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.107-107
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• 2018

무전해 니켈도금 용액의 성분은 Ni(II)염, 환원제, 적합한 금속 배위 리간드, 안정제 및 특정 특성 요구에 대한 첨가제를 포함한다. 일반적으로 도금 욕에는 미량의 안정제가 함유되어 있다. 만약 적절한 안정화 시스템이 없는 도금 욕에서 도금 공정 시 도금 시작 직후에 많은 양의 니켈 플레이크(Ni flake)가 생성되어 빠르게 도금 용액이 분해되어 더 이상 도금이 어렵게 된다. 그러나 무전해 도금 욕에서 안정제의 역할 및 도금 층에 미치는 영향에 대한 연구는 여전히 부족한 실정이다. 따라서 본 연구에서는 $Pb^{2+}$ 안정제 농도가 도금 층에 미치는 영향과 캐비테이션 침식 실험을 통해 그 내구성을 평가하고자 하였다. 무전해 니켈코팅을 위한 모재는 회주철(FC250)을 $19.5mm{\times}19.5mm{\times}5mm$의 크기로 가공하였다. 회주철의 인장강도는 $330N/mm^2$이며, 그 성분 조성(wt.%)은 3.23 C, 1.64 Si, 0.84 Mn, 0.016 P, 0.013 S 그리고 나머지는 Fe이다. 시험편은 SiC 페이퍼 #1200까지 연마하여 시험편의 표면 거칠기는 $1.6-2.1{\mu}m$ 범위 내로 제작하였다. 무전해 도금 전 시험편은 탈지를 위해 상온의 아세톤 용액에서 3분간 초음파 세척하고, $90^{\circ}C$의 알카리 수용액으로 5분간 세척하였다. 그리고 표면 활성화를 위한 산세척은 5% 황산용액에서 30초 동안 실시하였다. 도금조로 500mL 비커를 사용하였으며, 모든 시험편은 2시간 동안 무전해 니켈도금을 실시하였다. 그리고 니켈도금 층의 내식성과 내구성을 평가하기 위해 전기화학적 분극 실험을 통한 타펠분석과 ASTM G32 규정에 의거한 캐비테이션 침식 실험을 실시하였다. 그 결과 안정제 농도가 도금 속도와 도금 층의 성분 변화에 크게 영향을 미쳤으며, 그에 따라 도금 층의 내식성과 내구성이 크게 변화되었다.

• Journal of the korean academy of Pediatric Dentistry
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• v.42 no.1
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• pp.53-61
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• 2015

This study was conducted for the purpose of evaluating the stainless steel crowns on extracted primary molars and thus identifying frequent errors and defects. Visual assessment and micro-computed tomography (micro-CT) image analysis were performed on 97 primary molars for evaluation of the state of marginal adaptation, cement loss, secondary caries, ledge formation, attritive perforation and marginal polishing defect. The results were as follows: In the examination of object teeth by evaluation criteria, cement loss was found most frequently (98%), followed by secondary caries (42.3%), marginal polishing defect (41.2%), ledge formation (29.9%) and attritive perforation (17.5%), in this order. The cement loss at the margins showed a significant relationship with marginal gap and secondary caries: the larger the marginal gap is, the more frequent is the cement loss (p < 0.05). The average marginal gap was $0.31{\pm}0.26mm$ and showed the highest value in the maxillary 2nd primary molars. The location of the crown margin above the cementoenamel junction was found most frequently and it was found that the higher the crown margin is located, the less the marginal gap becomes (p < 0.05). In conclusion, it is thought very desirable to pay closer attention to crown margins and shapes for stainless steel crown restoration in order to minimize the marginal gaps and consequent cement loss.

• Journal of the Mineralogical Society of Korea
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• v.21 no.2
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• pp.201-208
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• 2008

Ceria ($CeO_2$) becomes one of important functional nanomaterials and a key abrasive material for chemical-mechanical planarization (CMP) of advanced integrated circuits in silicon semi-conductor technology. Two synthetic crystalline ceria (RT735, RT835) are studied by the Rietveld structural refinement to determine crystallite size and microstrain. Rietveld indices of RT735 and RT835 indicate good fitting with $R_p(%)=8.50$, 8.34; $R_{wp}(%)=13.4$, 13.5; $R_{exp}(%)=11.3$, 11.5; $R_B(%)=2.21$, 2.36; S(GofF: Goodness of fit)=1.2, 1.2, respectively. $CeO_2$ with space group Fm3m show a=5.41074(2), 5.41130(6) ${\AA}$, V=158.406(1), 158.455(3)${\AA}^3$ in dimension. Detailed Rietveld refinement reveals that crystallite size and microstrain are 37.42(1) nm, 0.0026 (RT735) and 72.80(2) nm, 0.0013 (RT835), respectively. It also shows that crystallite size and microstrain of ceria are inversely proportional to each other.

• The korean journal of orthodontics
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• v.31 no.6 s.89
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• pp.567-578
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• 2001

To investigate the difference of Texture exhibited on interproximal enamel surface with each different stripping method and the susceptibility of proximal enamel to demineralization after stripping and the application of a topical fluoride go] and sealant, one hundred human premolars, which were Previously extracted for orthodontic reasons were evaluated by means of Scanning electron microscopy and laser fluorescence. The results were as follows : 1. No matter what the initial stripping instrument was the furrows that resulted from all the stripping methods were not completely removed by careful polishing. 2. Among the enamel surfaces that were treated with three different initial abrasive instruments, followed by the same polishing method (Sof-$Lex^{(r)}$ disks), the enamel surfaces that were treated with 700 crosscut carbide bur showed the smoothest surfaces. 3. The stripped teeth, no matter what the initial stripping instrument was, were less resistant to initial demineralization than untreated teeth. But no difference in caries susceptibility according to differently stripped methods was found (p<(0.001). 4. Teeth treated with APF-gel or sealant were mote resistant to demineralization than those treated without other treatment after stripping (p<0.001). 5. Comparing groups treated with APF-gel to groups treated with sealant, the former was more resistant to demineralization than the tatter (p<0.05). In conclusion, enamel surfaces that were stripped jnterproximally were less resistant to demineralization even though various attempts were made to produce smooth, self-cleaning enamel surfaces. Therefore, additional treatment-sealant or calcifying/ fluoridating solution To the stripped enamel surfaces is recommended.

• Korean Journal of Materials Research
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• v.9 no.7
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• pp.724-734
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• 1999

The adhesion characteristics of the thermoplastic resins such as PE, PP PVC, PET and PS were investigated on the surfaces of conventional steel (SS41), steel (SS41P) treated with ultrasonic waves and the SS41P coated with several ceramic powders (SS41PC) by the plasma spray. Alumina (Al$_2$O$_3$), alumina titania (Al$_2$O$_3$95%, TiO$_2$ 5%) and zirconia yttria (ZrO$_2$ 95%, $Y_2$O$_3$5% ) were used for the materials plasma spray The morphologies, surface hardness, surface roughness, and contact angles on SS41, SS41P, and SS41PC were examined. The tensile shear strength and peel strength of the polymers which were attached to the surfaces of ceramics coated on SS41P also were measured. The tensile shear strength and peel strength of polymers adhered to ceramic surface coated on steel were found to be stronger than those of conventional steel. The tensile shear strength and peel strength of the polymers adhered on the surfaces of ceramics coated steel increased in the following order PE > PET > PP > PS > PVC. The high adhesion strength of PE may be attributed to the surface roughness and its anchor effect on the ceramic surface.

• Journal of Periodontal and Implant Science
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• v.35 no.3
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• pp.525-536
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• 2005

여러 연구들을 통해 많은 학자들이 임프란트 안정성(stability)은 표면의 특징에 달려있다고 생각하게 되었다. 표면의 구조, 에너지, 산화물(oxide) 두께와 표면성상(topography)등 임프란트의 표면의 특징은 임프란트와 골조직의 반응에서 중요한 역할을 하는 것이 알려짐에 따라 티타뮨 임프란트의 표면의 처리 방법에 큰 관심을 가지게 되었다. 그 중에서 티타늄 임프란트 표면의 산화피막화(anodization)가 한 방법으로 대두되었다. 이 방법은 전기화학적 방식으로 임프란트 표면에 거칠고(rough)두꺼우며(thick), 기공(pore)을 가지는 산화물 막을 형성하는 것으로 산화물의 두께는 coronal 부분(l-2 ${\mu}m$)으로부터 apical부분(7-10 ${\mu}m$)까지 증가하게 된다. 산화피막의 표면에는 다양한 크기의 수많은 기공이 주로 1-2 ${\mu}m$ 두께로 임프란트의 apical 부분에서 존재하며, 임프란트 표면의 거칠기는 conical 위부분에서 apical 부분까지 계속 증가한다(평균 Ra value=1.2 ${\mu}m$). 또 다른 표면 처리 방법으로는 blasting 후에 etching을 한 SLA 표면이 있다. 이 연구의 목적은 일반적으로 많이 이용되고 있는 anodized 표면과 SLA 표면의 조직학적 반응을 비교 분석하는 것이다. 24개 임프란트를(anodized surfaced implant-12개 , SLA-12개, 8mm ${\times}\;{\Phi}$ 4.3) 6마리 토끼의 오른쪽과 왼쪽 femur에 식립하였다. 12주후에 동물들을 희생하여 EXACT cutting-grinding system을 이용하여 샘플을 절단하고 800, 1200 및 4000 번 연마제(abrasive) paper로 20-50 ${\mu}m$ 까지 grinding하였다. 샘플은 Multiple staining 용액으로 염색하여 SLA 임프란트 군과 비교하였다. 골과 임프란트 사이에 연결을 TDI 프로그램을 이용하여 %로 측정하였다. SLA 임프란트 군 경우에는 골과 임프란트 사이의 연결이 $74{\pm}19%$ 이고, 양극 산화한 임프란트 군 경우에는 $77{\pm}9%$이었다. 양극 산화한 티타늄 임프란트의 골 접촉률이 SLA 표면 임프란트 경우과 통계학적으로 유의한 차이는 보이지 않았다.