A High Antibacterial Weakly Alkaline Barrier Slurry with the Tunable Selectivity

Abstract

Barrier chemical mechanical planarization (CMP) is a critical process in the manufacturing of integrated circuits (ICs). Bacterial infestation, the material removal rate (MRR) selectivity and slurry aging are important factors in the evaluation of barrier CMP slurry. In this paper, H2O2 concentration in a lower level was used to adjust the rate selectivity and enhance removal rate on copper to ensure the trench copper thickness reaches the target value. The effects of dodecyl dimethyl benzyl ammonium chloride (DDBAC) and 1,2-Benzisothiazol-3-one (BIT) on bacteria growth were investigated. The total organic carbon analysis and the after-cleaning defect map of the patterned wafer proved the DDBAC and BIT contained in the barrier slurry could prevent bacteria formation within four weeks. The effect of aging on the performance was investigated systematically for the slurry contained containing H2O2, DDBAC and BIT. Aging has been shown to have a small effect on zeta potential, particle size and viscosity of the slurry. The polishing rate and pH decrease with time due to chemical degradation of a part of H2O2. Luckily, the rate selectivity still remains at a high value over time and the barrier slurry after 30d has an effective performance in topography modification.