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Galvanic corrosion of Cu is a critical issue during the chemical mechanical polishing (CMP) process of barrier layer, especially when KIO4 is used as the oxidant in the polishing slurry. This paper focuses on the investigation of galvanic corrosion inhibitors (BTA and 1, 2, 4-triazole) for Cu/Ru couple in the KIO4-based solutions. The galvanic corrosion current of Cu was directly measured, and the corrosion inhibition efficiencies (CIE) were calculated. Results show that both BTA and 1, 2, 4-triazole are effective galvanic corrosion inhibitors of Cu. The CIE of 5 mM BTA and 2 mM 1, 2, 4-triazole is up to 69.4 and 59.7, respectively. On this basis, the corrosion inhibition mechanism was proposed. BTA forms a complete and tight three-dimensional multilayer structure on Cu when the concentration is over 0.5 mM. With regard to 1, 2, 4-triazole, the protective film on Cu is two-dimensional, and excessive dosage of 1, 2, 4-triazole will reduce the stability of the surface film, as well as the corrosion inhibition efficiency of Cu.

Chemical mechanical polishing (CMP) of GaN(0001) with a H2O2-SiO2-based slurry is investigated in this paper. The result shows that an atomically flat surface with a roughness of 0.065 nm is obtained after polishing. Compared with a SiO2-based slurry, the H2O2-SiO2-based slurry can realize a higher material removal rate (MRR) and a better surface quality with less scratches. The pH value mainly affects the mean particle size of SiO2 and the chemical environment of the corrosion reaction with H2O2, resulting in different MRRs. An off-site auxiliary polishing method is employed along with the H2O2-SiO2-based polishing system using ultraviolet light to shine the outlet of slurry in order to catalyze the production of substance for oxidation, and it is proved to be efficient by improving the MRR to 103 nm/h. Physical and mathematic removal models are proposed to describe the removal mechanism of GaN CMP.