• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.05a
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• pp.101-102
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• 2006

BTO ($BaTiO_3$) thin film is one of the high dielectric materials for high-density dynamic random access memories (DRAMs) due to its relatively high dielectric constant, It is generally known that BTO film is difficult to be etched by plasma etching, but high etch rate with good selectivity to pattern mask was required. The problem of sidewall angle also still remained to be solved in plasma etching of BTO thin film. In this study, we first examined the patterning possibility of BTO film by chemical mechanical polishing (CMP) process instead of plasma etching. The sputtered BTO film on TEOS film as a stopper layer was polished by CMP process with the sell-developed $BaTiO_3$- and $TiO_2$-mixed abrasives slurries (MAS). respectively. The removal rate of BTO thin film using the $BaTiO_3$-mixed abrasive slurry ($BaTiO_3$-MAS) was higher than that using the $TiO_2$-mixed abrasive slurry ($TiO_2$-MAS) in the same concentrations. The maximum removal rate of BTO thin film was 848 nm/min with an addition of $BaTiO_3$ abrasive at the concentration of 3 wt%.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.1278-1282
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• 2004

수열처리법으로 nano-sized $CeO_2$ 입자를 $Al_3O_3$ 입자의 표면에 균일하게 코팅하여 $AL_2O_3/O_2$ composite 연마 입자를 제조하었다. 제조된 $Al_2O_3\CeO_2$ composite 입자의 뭍성을 TEM, XRD, zeta potential analyzer 및 particle size analyzer로 측징하였다. $Al_2O_3/CeO_2$ composite 입자와 구성된 슬러리와 비교 시료로서 $Al_2O_3$와 $CeO_2$ 입자를 혼합한 슬러리를 사용하여 thermal oxide film에 대한 연마특성을 평가하였다. 연마슬러리에 포함된 $A1_2O_3/CeO_2$ composite 입자와 $Al_2O_3$와 $CeO_2$ 혼합입자에서 나노 크기의 세리아 입자가 sub-micron 크기의 알루미나 입자의 표면에 균일하게 코팅되므로서 $Al_2O_3$ 단일 성분의 슬러리에 비해 removal rate(RR)는 106 nm/min, WIWNU는 $8\sim9%$, roughness는 $2.6{\AA}$의 향상된 연마 특성을 나타내었다. 알루미나 입자의 불규칙한 형상 때문에 $Al_2O3/CeO_2$ composite 슬러리와 $Al_2O_3$ 와 $CeO_2$ 혼합슬러리의 연마 특성이 비슷한 수준을 나타내었다.

• The Journal of Advanced Prosthodontics
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• v.13 no.1
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• pp.1-11
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• 2021

PURPOSE. The study compared the color change, lightness, and translucency of hybrid resin ceramics exposed to toothbrush abrasion and surface treatment. MATERIALS AND METHODS. Four hybrid ceramics [Lava Ultimate (LU), Vita Enamic (EN), Shofu HC (SH), and Crystal Ultra (CU)] were compared with a glass-ceramic (Vita Mark II) control. One hundred and twenty specimen blocks were prepared using a precision saw machine. Specimens in each material were divided into four subgroups based on the surface treatment (polishing or staining) and a storage medium (water or citric acid). Simulated tooth brushing with a mixture of 100 RDA (radioactive abrasives) with 0.3 ml distilled water was used for 3650 cycles (7300 strokes) for each specimen. Measurements for the color change, lightness, and translucency were measured after toothbrushing using a spectrophotometer. Statistical analysis compared outcomes using paired t-test, ANOVA, and Tukey post hoc test. RESULTS. The maximum color change was identified in SH (stained acid) [1.44 (0.40)], whereas the lowest was identified in EN (polished water) [0.66 (0.16)] material. The maximum and minimum loss of surface translucency was observed in SH (polished water) [12.3 (0.52)] and EN (stained acid) [6.5 (0.55)] specimens, respectively. Lastly, loss of lightness was the highest in VM (polished acid) [69 (0.95)], whereas the lowest was observed in CU (stained water) [56.7 (0.86)]. CONCLUSION. The comparison presented a significant effect of toothbrush abrasion on translucency and lightness of the hybrid resin ceramics. Color change was not significantly influenced irrespective of the storage medium employed. Surface staining demonstrated the preservation and stability of color and optical properties under the influence of toothbrush abrasion and chemical trauma.