Effects of CMP Slurry Additives on the Rate of Agglomeration of Alumina Particles

The rate of agglomeration of alumina particles in 1 mM KNO3 solutions with various additives with a range of pH values was measured. The suspensions tested contained only glycine and glycine, H2O2, benzotriazole, and sodium dodecyl sulfate. A fractal dimensional analysis was used to analyze the rate data to indicate the agglomeration mechanism. At pH 4 no aggregation was observed in the glycine only suspension, however significant aggregation occurred in the other suspension, reaching sizes greater than 3 μm within 2 min. Slow agglomeration was observed at pH 7.5 for both suspensions. Both suspensions at pH 10 showed immediate aggregation to mean sizes greater than 3 μm. However, adjustment of the suspension pH was sufficient to increase or reduce the aggregate size