Enhancing Slurry Stability and Surface Flatness of Silicon Wafers through Organic Amine-Catalyzed Synthesis Silica Sol

Abstract

The stability of slurries used for chemical mechanical polishing (CMP) is a crucial concern in industrial chip production, influencing both the quality and cost-effectiveness of polishing fluids. In silicon wafer polishing, the conventional use of commercial neutral silica sol combined with organic bases often leads to slurry instability. To address this issue, this study proposes organic amines—specifically ethanolamine (MEA), ethylenediamine (EDA), and tetramethylammonium hydroxide (TMAOH)—as catalysts for synthesizing alkaline silica sol tailored for silicon wafer polishing fluids. Sol–gel experiments and zeta potential measurements demonstrate the efficacy of this approach in enhancing the stability of silica sol. The quantitative analysis of surface hydroxyl groups reveals a direct correlation between enhanced stability and increased hydroxyl content. The application of the alkaline silica sol in silicon wafer polishing fluids improves polishing rates and enhances surface flatness according to atomic force microscopy (AFM). In addition, electrochemical experiments validate the capability of this polishing solution to mitigate corrosion on silicon wafer surfaces. These findings hold significant implications for the advancement of chemical mechanical polishing techniques in the field of integrated circuit fabrication.

Keywords

• monocrystalline silicon wafer
• chemical mechanical polishing
• organic amine
• silanol groups
• silica nanoparticles