Effects of CMP slurry additives on the agglomeration of alumina nanoparticles 1: General aggregation rate behavior

• The general aggregation behavior of alumina nanoparticles was investigated.
• Alumina aggregate sizes and zeta potential were measured with a variety of additives.
• Observed behaviors were reversible aggregation and steady aggregation.
• Aggregation at acidic pH was observed in suspensions with sodium dodecylsulfate.

The aggregation behavior for 150 nm alumina particles suspended in 1 mM KNO3 solutions with various additives used in chemical mechanical planarization of copper was investigated. Three behaviors were observed: no aggregation, reversible aggregation where large agglomerates formed almost instantaneously, and steady aggregation where particle sizes grew over the duration of the measurement. In general steady aggregation occurred at high pH for all suspensions, while no aggregation occurred at acidic pH, except with suspensions with sodium dodecyl sulfate, where reversible aggregation was observed. No aggregation was observed at near neutral pH for all suspensions. Zeta potential and isoelectric points for each suspension were also measured.

Figure optionsDownload high-quality image (137 K)Download as PowerPoint slide