Study of PH and down pressure effects on silicon dioxide dielectric chemical mechanical polishing (CMP)

Understanding the pH and down pressure effects is critical in elucidating the chemical and mechanical mechanisms in CMP. This paper describes the variation in polishing rate by non-agglomerated silicon dioxide particles. The electrostatic repulsion force, solubility of amorphous silica, and total contact area at the pad-particles-wafer interface are found to be important factors in determining polishing performance. In situ friction force measurements are used to detect the variation of interfacial contact during polishing. Surface finishes and interaction force of silica/silica were investigated using Atomic Force Microscopy (AFM). The examination of the polishing behavior altered by pH and down pressure will provide an insight into the polishing mechanism for desired CMP performance.