Effects of slurry formulations on chemical-mechanical polishing of low dielectric constant polysiloxanes: hydrido-organo siloxane and methyl silsesquioxane

In this study, the film properties and chemical-mechanical polishing (CMP) characteristics of the low dielectric constant polymers hydrido-organo silo xane and methyl silsesquioxane are presented. The molecular structure and f ilm properties of both polymers were characterized by their Fourier transfo rm infrared spectra, refractive indices, dielectric constants, and atomic f orce microscopy diagrams. The CMP characteristics were studied by using dif ferent kinds of slurries and surfactants. The investigated slurries include d SiO2 based slurry (SS-25), ZrO2 based slurry (Al), and Al2O3 based slurry (8104/H2O). Three kinds of surfactants were used to increase the contact a rea between the abrasive and polymer surface and thus polishing results wer e affected, which included nonionic Triton X-100, anionic dodecylsulfate so dium salt, and cationic tetramethylammonium hydroxide. The experimental res ults suggest that the organic content, the hardness and charge status of th e abrasive, the polarity and charge status of the surfactant significantly affect the polishing results. The present study demonstrates that the CMP c haracteristics of low dielectric constant polysiloxanes can be controlled b oth chemically and mechanically. (C) 2000 American Vacuum Society. [S0734-2 11X(00)03201-7].