Influence of H2O2 on performance of corrosion inhibition of triazole derivatives for copper in alkaline chemical mechanical polishing slurry

Abstract

Chemical mechanical polishing (CMP) is a critical process in semiconductor manufacturing. Copper corrosion in the alkaline CMP slurry, particularly in the presence of hydrogen peroxide (H₂O₂), poses a significant challenge. The use of corrosion inhibitors, such as 1,2,4-triazole (TAZ) and its derivatives, is essential to improve the performance of copper interconnects. This study investigates the corrosion inhibition of three triazole derivatives, 3-amino-1,2,4-triazole (ATA), 3-mercapto-1,2,4-triazole (MT) and 3-amino-5-mercapto-1,2,4-triazole (AMTA), for copper in alkaline CMP slurry. Electrochemical measurements reveal that ATA exhibited the highest inhibition efficiency of 92.7 % at 10 mM, followed by MT (89.9 % at 20 mM) and AMTA (83.7 % at 20 mM). All three derivatives are mixed-type inhibitors, predominantly exhibiting anodic inhibition characteristics. An antagonistic effect occurs when the mercapto group (-SH) and amino group (-NH₂) are present within the triazole ring. Surface characterization using atomic force microscopy (AFM) and scanning electron microscopy (SEM) confirms that ATA significantly improves the surface quality of copper. X-ray photoelectron spectroscopy (XPS) analysis shows that the presence of H₂O₂ oxidizes the -SH into disulfide bonds (S-S), thereby reducing the corrosion inhibition performance of MT and AMTA. Theoretical calculations further show that ATA adsorbs parallel to the copper surface, while MT and AMTA adsorb in an inclined mode. These findings provide guidance for the design and development of new organic azole inhibitors for copper CMP processes.