CHARACTERIZATION OF THE CHEMICAL-MECHANICAL POLISHING PROCESS-BASED ON NANOINDENTATION MEASUREMENT OF DIELECTRIC FILMS

Abstract

To better understand variations in the rate at which material is removed from a wafer during chemical-mechanical polishing (CMP), knowledge of the mechanical properties of the wafer surface is required. The nanoscale mechanical. properties of undoped dielectric films were investigated using the nanoindentation technique. Crack resistance examined from the loading curve suggested that precursor cracks for SiH4-atmospheric pressure chemical deposition films with a tensile stress, as compared with other dielectric films with compressive stresses, appeared in the earlier stage of indentation. The hardness of dielectric films determined from the unloading curve could be considerably dependent on the film's preparation methods. Correlation between the Si-O bond densities and hardness were also studied. Experimental results showed that there was a Linear relationship between the surface hardness and the removal rates of the undoped dielectric films under a well-controlled CMP process.