• Journal of Mechanical Science and Technology
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• 제20권2호
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• pp.227-233
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• 2006

Engineering ceramics have many unique characteristics both in mechanical and physical properties such as high temperature hardness, high thermal, chemical and electrical resistance. However, its machinability is very poor in conventional machining due to its high hardness and severe tool wear. In the current experimental study, alumina $(Al_2O_3)$ was ultrasonically machined using SiC abrasives under various machining conditions to investigate the material removal rate and surface quality of the machined samples. Under the applied amplitude of 0.02mm, 27kHz frequency, three slurry ratios of 1:1, 1:3 and 1:5 with different tool shapes and applied static pressure levels, the machining was conducted. Using the mesh number of 240 abrasive, slurry ratio of 1:1 and static pressure of $2.5kg/cm^2$, maximum material removal rate of $18.97mm^3/min$ was achieved. With mesh number of 600 SiC abrasives and static pressure of $3.0kg/cm^2$, best surface roughness of $0.76{\mu}m$ Ra was obtained.

• 청정기술
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• 제12권4호
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• pp.232-237
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• 2006

본 연구에서는 분무건조법으로 유동층용 아연계 탈황제를 제조하는 과정에서, 슬러리의 pH와 점도가 성형된 탈황제의 내마모성에 미치는 영향이 조사되었다. 아연계 탈황제의 내마모성을 개선하기 위하여 무기성 결합제로 알루미나 졸이 사용되었으며 슬러리에 들어있는 무기 결합제의 효과적인 분산을 위하여 슬러리의 pH가 조절되었다. 슬러리의 pH가 높아 알칼리성인 경우 알루미나 졸이 겔 상태로 변하여 슬러리의 점도가 높아지며 성형된 탈황제의 내마모성이 저하 되었다. 본 연구의 실험결과, 슬러리의 pH가 6으로 조절되어 성형된 탈황제가 가장 좋은 내마모성을 나타내었다. 또한 슬러리의 점도에 따라 성형된 탈황제의 밀도와 표면적 그리고 기공도가 달라졌으며, 이로부터 탈황제의 마모 특성이 결정됨을 알 수 있었다. 성형된 탈황제의 내마모성은 밀도가 높고, 표면적과 기공도가 낮을수록 높아지는 것으로 나타났으며, 최적 점도범위는 약 400-550 cP 정도였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.57-58
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• 2006

In MIM (metal insulator metal) capacitor, Ru (ruthenium) has been suggested as new bottom electrode due to its excellent electrical performance, a low leakage of current and compatibility to the high dielectric constant materials. In this case of Ru bottom electrode, CMP (chemical mechanical planarization) process was needed m order to planarize and isolate the bottom electrode. In this study, the effect of chemical A on polishing and etching behavior was investigated as functions of chemical A concentration, abrasive particle and pressure. Chemical A was used as oxidant and etchant. The thickness of passivation layer on the treated Ru surface increased with the increase of chemical A concentration. The etch rate and removal rate of Ru were increased by the addition of chemical A. The removal rate was highest m slurry of pH 9 with the addition of 0.1 M chemical A and 2 wt% alumina at 4 psi. The maximum removal rate is about 80 nm/min.

• Transactions on Electrical and Electronic Materials
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• 제6권1호
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• pp.29-32
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• 2005

Chemical mechanical polishing is an essential process in the production of copper-based chips. On this work, the stability of hydrogen peroxide ($H_{2}O_{2}$) as an oxidizer of copper CMP slurry has been investigated. $H_{2}O_{2}$ is known as the most common oxidizer in copper CMP slurry. But $H_{2}O_{2}$ is so unstable that its stabilization is needed using as an oxidizer. As adding KOH as a pH buffering agent, stability of $H_{2}O_{2}$ decreased. However, $H_{2}O_{2}$ stability in slurry went up with putting in small amount of BTA as a film forming agent. There was no difference of $H_{2}O_{2}$ stability between pH buffering agents KOH and TMAH at similar pH value. Addition of $H_{2}O_{2}$ in slurry in advance of bead milling led to better stability than adding after bead milling. Adding phosphoric acid resulted in the higher stability. Using alumina C as an abrasive was good at stabilizing for $H_{2}O_{2}$.

• Transactions on Electrical and Electronic Materials
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• 제4권6호
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• pp.28-31
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• 2003

Copper CMP in terms of the effect of slurry chemicals (oxidizer, corrosion inhibitor, complexing agent) on the process characteristics has been performed. Corrosion inhibitors, benzotriazole (BTA) and tolytriazol (TTA) were used to control the removal rate and avoid isotropic etching. When complexing agent is added with H$_2$O$_2$ 2 wt% in the slurry, the corrosion rate was presented very well. In the case of complexing agent, it was estimated that the proper concentration is 1 wt%, because the addition of tartaric acid to alumina slurry causes low pH and the slurry dispersion stability become unstable. There was not much change of the removal rate. It was assumed that BTA 0.05 wt% is suitable. Most of all, it was appeared that BTA is possible to be replaced by TTA. TTA was distinguished for the effect among complexing agents.

• 한국세라믹학회지
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• 제48권2호
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• pp.168-172
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• 2011

Alumina powder was added in a general porcelain (Backja) with clay, feldspar and quartz contents to promote the mullite ($3Al_2O_3{\cdot}2SiO_2$) generation in the porcelain. Low melting materials ($B_2O_3(450^{\circ}C)$, $MnO_3(940^{\circ}C)$, CuO($1080^{\circ}C$)) were doped at ~3 wt% to modify the sinterability of porcelain with a high alumina contents and promote the mullite generation. Green body was made by slip casting method with blended slurry and then, they were fired at $1280^{\circ}C$ for 1hr by a $2^{\circ}C/min$. Densifications of samples with high alumina contents (20~30 wt%) were impeded. As the doping contents of low melting materilas increased, the sinterability of samples was improved. The shrinkage rate and bulk density of samples were improved by doping with low melting materials. Mullite phase increased with increasing the low melting contents in the phase analyses. This means lots of alumina and quartz were transformed into mullite phase by low melting contents doping. In the results, high bending strength of samples with high alumina contents was accomplished by improving the densification and mullite generation in the porcelain.

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2001년도 추계 기술심포지움
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• pp.230-234
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• 2001

본 연구에서는 Alumina(A1$_2$O$_3$) based Slurry를 이용하여 CU CMP를 할 때 첨가제의 영향을 Removal rate와 Etch rate 측면에서 조사하였다. 각각의 첨가제의 종류와 조성의 변화에 따라 Polishing에 미치는 영향을 연구하였다. Cu의 Removal rate는 Etch rate와 달리 Organic acid의 종류에 직접적으로 영향을 받는다. Citric acid는 높은 Removal rate와 슬러리 내에서 안정성이 가장 좋은 결과를 보이고 있다. Citric acid의 농도가 증가하면 증가할수록 Removal rate는 증가하였다. BTA의 농도에 따라서 Cu의 Removal rate와 Etch rate의 감소를 확인할 수 있다. EDTA의 농도에 따라서는 증가함을 볼 수 있다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.647-648
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• 2005

The development of CMP slurry chemistry for Ni that provides good CMP performance is the key for nickel based MEMS device fabrication. In this study, CMP of nickel was performed using different slurry versus oxidizer ratios arid different oxidizers also alumina particles as an abrasive.

• 한국정밀공학회지
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• 제15권8호
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• pp.39-45
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• 1998

In the previous study. the powder casting was attempted as the rapid tooling. The powder casting was the process to cast dry powder into the casting mold transferred from R/P model and infiltrate the liquid binder to solidify the powder. And then, the melted copper was infiltrated to control the shrinkage rate of the final mold Conseqently, the shrinkage rate was under 0.1% through that process. The mechanical characteristic was also excellent. Generally, in the slurry casting, the alumina powder and the water soluble phenol were mainly used. However, the mechanical property of the phenol was not good enough to apply to molds directly. In this study, aluminium powder filled with epoxy is applicated to the slurry casting to solve these problems. The mechanical and thermal properties are better than phenol because the epoxy is the thermosetting resin. We achieved a successful result that the shrinkage rate is shortened about 0.047%. Futhermore, the manufacturing time and cost savings are significant. Finally, we assume that the developing possibility of this process is very optimistic.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.206-209
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• 2002

The fixed abrasive pad(FAP) has been introduced in chemical mechanical polishing(CMP) field recently. In comparison with the general CMP which uses the slurry including abrasives, FAP takes advantage of planarity. resulting from decreasing pattern selectivity and defects such as dishing due to the reduction of abrasive concentration especially. This paper introduces the manufacturing technique of $Al_2$O$_3$-FAP using hydrophilic polymers with swelling characteristic in water and explains the self.texturing phenomenon. It also focuses on the chemical effects on tungsten film and the FAP is evaluated on the removal rate as a function of chemicals such as oxidizer, catalyst, and acid. The removal rate is achieved up to 1000A1min as about 70 percents of the general one. In the future. the research has a plan of the advanced FAP and chemicals in tungsten CMP considering micro-scratch, life-time, and within wafer non-uniformity.