| Summary: | 碩士 === 國立臺灣大學 === 化學工程學研究所 === 102 === This study includes two parts: copper corrosion and effect of ammonium persulfate-based slurry on Cu/Ru chemical mechanical polishing. We used three electrode-system to investigate the corrosion of copper in various conditions. Copper was electrodeposited on a rotating disk electrode with the thickness of 0.98 μm. After the corrosion experiments, the remaining copper was measured. We found that sparging nitrogen for 10 minutes could remove 90% oxygen in the solution. The corrosion rate of copper increases as temperature increases. Sparging oxygen in the electrolytes has the highest corrosion rate; on the other hand, sparging argon has the lowest corrosion rate. At various pH values, the corrosion rates at pH 5 and 6 are lower than pH 7-9. Two organic inhibitors has also been investigated: benzotriazole and benzimidazole, and it was found that benzotriazol is better than benzimidazole for copper corrosion inhibitor. Adding 10 ppm BTA in the solution can decrease the corrosion rate, and the corrosion rate is 1.2 × 10-3 nm/s in 0.1 M (NH4)2SO4 solution.
In the Cu/Ru CMP experiments, by performing electrochemical measurements such as polarization and impedance spectroscopy, the electrochemical characteristics has been studied. Besides, surface morphological analysis after CMP was carried out by atomic force microscopy. The experimental results showed that the ammonium persulfate-based slurry at pH 6 has the best performance. At pH 6, there is the lowest galvanic corrosion, the removal rate of Ru was found to match that of Cu. After CMP in (NH4)2S2O8-based slurry, the copper surface roughness reduces to 14.3 nm; the ruthenium surface roughness reduces to 19.0 nm.
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