• The Journal of Korean Academy of Prosthodontics
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• v.61 no.3
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• pp.179-188
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• 2023

Purpose. The purpose of this study was to evaluate the effect of surface treatments on the shear bond strength of two types of zirconia (3-TZP and 5Y-PSZ) with resin cement. Materials and methods. Two different types of zirconia specimens with a fully sintered size of 14.0×14.0×2.0 mm³ were prepared, polished with 400, 600, and 800 grit silicon carbide paper, and buried in epoxy resin. They were classified into four groups each control, sandblasting, primer, and sandblasting & primer. Cylindrical resin adhered to the surface-treated zirconia with resin cement. It was stored in distilled water (37℃) for 24 hours, and a shear bond strength test was performed. The normality of the experimental group was confirmed with the Kolmogorov-Smirnov & Shapiro-Wilk test. The interaction and statistical difference were analyzed using a two-way ANOVA. A post-hoc analysis was performed using Dunnett T3. Results. As a result of two-way ANOVA, there was no significant difference in shear bonding strength between zirconia types (P > .05), but there was a significant correlation in the sandblasting, primer, and alumina sandblasting & primer group (P < .05). Dunnett T3 post-test showed that, regardless of the type of zirconia, shear bonding strength was sandblasting & primer > Primer > sandblasting > control group (P < .05). Conclusion. There was no difference in shear bond strength between the types of zirconia. The highest shear bond strength was shown when the mechanical and chemical treatments of the zirconia surface was performed simultaneously.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.10a
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• pp.23-23
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• 2011

Chemical-Mechanical Planarization (CMP) 공정이란 화학적 반응 및 기계적인 힘이 복합적으로 작용하여 표면을 평탄화하는 공정이다. 이러한 CMP 공정은 반도체 산업에서 회로의 고집적화와 다층구조를 형성하기 위하여 도입되었으며 반도체 제조를 위한 필수공정으로 그 중요성이 강조되고 있다. 특히 최근에는 Inter-Level Dielectric (ILD)의 형성과 Shallow Trench Isolation (STI) 공정에서실리콘 산화막을 평탄화하기 위한 CMP 공정에 대해 연구가 활발히 이루어지고 있다. 그러나 CMP 공정 후 scratch, pitting corrosion, contamination 등의 Defect가 발생하는 문제점이 존재한다. 이 중에서도 scratch는 기계적, 열적 스트레스에 의해 생성된 패드의 잔해, 슬러리의 잔유물, 응집된 입자 등에 의해 표면에 형성된다. 반도체 공정에서는 다양한 종류의 실리콘 산화막이 사용되고 gks이러한 실리콘 산화막들은 종류에 따라 경도가 다르다. 따라서 실리콘 산화막의 경도에 따른 CMP 공정 및 이로 인한 Scratch 발생에 관한 연구가 필요하다고 할 수 있다. 본 연구에서는 scratch 형성의 거동을 알아보기 위하여 boronphoshposilicate glass (BPSG), plasma enhanced chemical vapor deposition (PECVD) tetraethylorthosilicate (TEOS), high density plasma (HDP) oxide의 3가지 실리콘 산화막의 기계적 성질 및 이에 따른 CMP 공정에 대한 평가를 실시하였다. CMP 공정 후 효율적인 scratch 평가를 위해 브러시를 이용하여 1차 세정을 실시하였으며 습식세정방법(SC-1, DHF)으로 마무리 하였다. Scratch 개수는 Particle counter (Surfscan6200, KLA Tencor, USA)로 측정하였고, 광학현미경을 이용하여 형태를 관찰하였다. Scratch 평가를 위한 CMP 공정은 실험에 사용된 3가지 종류의 실리콘 산화막들의 경도가 서로 다르기 때문에 동등한 실험조건 설정을 위해 동일한 연마량이 관찰되는 조건에서 실시하였다. 실험결과 scratch 종류는 그 형태에 따라 chatter/line/rolling type의 3가지로 분류되었다 BPSG가 다른 종류의 실리콘 산화막에 비해 많은 수에 scratch가 관찰되었으며 line type이 많은 비율을 차지한다는 것을 확인하였다. 또한 CMP 공정에서 압력이 증가함에 따라 chatter type scratch의 길이는 짧아지고 폭이 넓어지는 것을 확인하였다. 본 연구를 통해 실리콘 산화막의 경도에 따른 scratch 형성 원리를 파악하였다.

• Tribology and Lubricants
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• v.35 no.6
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• pp.330-336
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• 2019

Conditioning is a process involving pad surface scraping by a moving metallic disk that is electrodeposited with diamond abrasives. It is an indispensable process in chemical-mechanical planarization, which regulates the pad roughness by removing the surface residues. Additionally, conditioning maintains the material removal rates and increases the pad lifetime. As the conditioning continues, the pad profile becomes unevenly to be deformed, which causes poor polishing quality. Simulation calculates the density at which the diamond abrasives on the conditioner scratch the unit area on the pad. It can predict the profile deformation through the control of conditioner dwell time. Previously, this effect of the diamond shape on conditioning has been investigated with regard to microscopic areas, such as surface roughness, rather than global pad-profile deformation. In this study, the effect of diamond shape on the pad profile is evaluated by comparing the simulated and experimental conditioning using two conditioners: a) random-shaped abrasive conditioner (RSC) and b) uniform-shaped abrasive conditioner (USC). Consequently, it is confirmed that the USC is incapable of controlling the pad profile, which is consistent with the simulation results.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.50-53
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• 2003

CMP (chemical mechanical polishing) process remained to solve several problems in deep sub-micron integrated circuit manufacturing process. especially consumables (polishing pad, backing film, slurry, pad conditioner), one of the most important components in the CMP system is the slurry. Among the composition of slurries (buffer solution, bulk solution, abrasive particle, oxidizer, inhibitor, suspension, antifoaming agent, dispersion agent), the abrasive particles are important in determining polish rate and planarization ability of a CMP process. However, the cost of abrasives is still very high. So, in order to reduce the high COO (cost of ownership) and COC (cost of consumables) in this paper, we have collected the silica abrasive powders by filtering after subsequent CMP process for the purpose of abrasive particle recycling. And then, we have studied the possibility of recycle of reused silica abrasive through the analysis of particle size and hardness. Also, 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.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.23 no.2
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• pp.101-107
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• 2013

Cerium compounds such as Cerium hydroxide ($Ce(OH)_3$), Cerium chloride ($CeCl_3{\cdot}nH_2O$), Cerium carbonate hydrate ($Ce_2(CO_3)_3{\cdot}8H_2O$), Cerium oxide ($CeO_2$) were synthesized using recycled Ce precursor. Cerium(IV) oxide of nanoparticles were obtained by Ultra-sonication. Cerium-sodium- sulfate compound was synthesized through acid-leaching and addition of sodium sulfate from 99 wt% purity of Ce precursor as a starting material that was recycled from the waste polishing slurry. Moreover Cerium hydroxide was obtained from Cerium-sodium-sulfate compound by adding to sodium hydroxide solution. Then Cerium chloride was synthesized by adding of hydrochloric acid to Cerium hydroxide. Needle-shaped Cerium carbonate hydrate was synthesized in the continuous process and Cerium(IV) oxide with 30~40 nm size was subsequently obtained by the calcinations and dispersion.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.23 no.2
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• pp.86-92
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• 2013

$SF_6/O_2$ inductively coupled plasmas were employed to texture Si surface as a pretreatment for nanocrystalline diamond film growth. It was found that the $SF_6/O_2$ plasma texturing provided a very wide process window where normalized roughness values in the range of 2~16 could be obtained. Significantly improved nucleation densities of ${\sim}6.5{\times}10^{10}cm^{-2}$ compared to conventional mechanical abrasion were achieved after seeding for the textured Si substrate.

• Korean Journal of Materials Research
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• v.5 no.6
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• pp.627-632
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• 1995

W-Cu composites utilize the high electrical conductivity of copper and arc erosion resistance of tungsten to provide properties better suited to electrical contact applications than either tungsten or copper alone. W-Cu composite materials were milled in an attritor with an impeller speed of 300rpm for various milling times. The milled powders were compacted at 300MPa into cylinders, 16m in diameter, and approximately 4m high. Sintering was performed in dry H$_2$at temperature ranging from 1200$^{\circ}C$ to 1400$^{\circ}C$. Samples were sectioned and were polished for scanning electron microscopy (SEM) of microstructures. Homogeneous W-Cu composites were formed after 10 hours mechanical alloying and could be attained 99% density at 1330$^{\circ}C$. As mechanical alloying time increased, Fe-concentration was increased linearly. Intermetallic compound formation interupted the growth of W particles Increased hardness.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05c
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• pp.145-148
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• 2003

Recently, the recycle of CMP (chemical mechanical polishing) slurries have been positively considered in order to reduce the high COO (cost of ownership) and COC (cost of consumables) in CMP process. Among the composition of slurries (buffer solution, bulk solution, abrasive particle, oxidizer, inhibitor, suspension, antifoaming agent, dispersion agent), the abrasive particles are one of the most important components. Especially, the abrasive particles of slurry are needed in order to achieve a good removal rate. However, the cost of abrasives, is still very high. In this paper, we have collected the silica abrasive powders by filtering after subsequent CMP process for the purpose of abrasive particle recycling. And then, we have studied the possibility of recycle of reused silica abrasive through the analysis of particle size and hardness. Also, 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 slury, 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.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.329-329
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• 2010

반도체 및 디스플레이의 진공부품은 알루미늄 모제에 전해연마법(electrolytic polishing), 양극산화피막법(Anodizing), 플라즈마 용사법(Plasma spray) 등을 사용하여 $Al_2O_3$ 피막을 성장시켜 사용되고 있다. 반도체 제조공정 중 30~40% 이상의 비중을 차지하는 식각(etching) 및 증착(deposition) 공정은 대부분 플라즈마를 사용하고 있다. 플라즈마에 의해 화학적, 물리적 침식이 발생하여 코팅막에 손상을 일으켜 코팅막이 깨지거나 박리되면서 다량의 Particle을 생성함으로써 생산수율에도 문제를 야기 시킨다고 알려져 있다. 하지만 이들 코팅막을 평가하는 방법은 거의 전무하여 산업계에서 많은 애로를 겪고 있다. 이러한 코팅부품의 내플라즈마 성능평가 방법과 기준이 없어 적절한 교체시기를 파악하기 위한 코팅부품의 손상정도를 정량화 및 평가 방법의 표준화를 구축하는 연구를 수행하였다. 본 연구에서는 이러한 소재의 특성평가를 위해 공정에서 사용 중 손상되어 교체된 샘플의 모폴로지 관찰하고 내전압 측정으로 전기적 특성을 분석하여 손상 전, 후의 변화를 관찰하였다. 또한 플라즈마의 영향에 따른 코팅 막 형태 변화 및 전기적 특성의 변화를 알아보기 위하여 양극산화피막법(Anodizing)으로 $Al_2O_3$를 성장시킨 평가용 샘플을 제작한 후, Plasma chamber 장비를 이용하여 플라즈마 처리에 따른 코팅막의 내전압, 식각율, 표면 미세구조의 변화를 측정하였고 이를 종합적으로 고려하여 진공 장비용 코팅부품의 공정영향에 의한 내플라즈마 특성평가방법 개발에 관하여 연구하였다. 이러한 실험을 통해 플라즈마 처리 후 코팅 막에 크랙이 발생되는 것을 확인할 수 있었고 코팅 막의 손상으로 전기적 특성이 감소를 것을 확인할 수 있었다. 또한 ISPM 장비를 이용하여 진공 장비용 코팅부품이 플라즈마 공정에서 발생하는 오염 입자를 측정할 수 있는 방법을 연구하였다. 이러한 결과를 이용하여 진공공정에서 사용되는 코팅부품이 플라즈마에 의한 손상정도를 정량화 하고 평가방법을 개발하여 부품 양산업체의 진공장비용 코팅부품 개발 신뢰성 향상이 가능할 것으로 본다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.9
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• pp.1105-1111
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• 2011

The objective of this study is to investigate the influence of surface roughness on the morphology of aluminum 6061-T6 alloy after irradiation with a Nd:YAG pulsed laser. The test specimen was prepared by a polishing process using a diamond paste ($1{\mu}m$) and emery polishing papers (#100, #220, #600, #2400) to obtain different initial surface roughness. After irradiation with ten pulsed-laser shots, the surface morphology was examined by using scanning electron microscopy (SEM), optical microscopy (OM), and atomic force microscopy (AFM). The diameter of the melted zone increased with the surface roughness because the multiple reflections and absorption of the laser beam occurred on the surface because of the surface roughness, so that the absorptance of the laser beam changed. This result was verified using the relative absorptance calculated from the diameter of the melted zone with the surface roughness and the diameter increased with the average surface roughness.