Removal characteristics of hillock on SnO2 thin film by chemical mechanical polishing process

Abstract

SnO 2 is one of the most suitable materials for gas sensors. The microstructure and surface morphology of SnO2 films must be controlled because the electrical and optical properties of SnO2 films depend on these characteristics. We investigated the effects of chemical mechanical polishing (CMP) on the variation of morphology of SnO2 films prepared by rf sputtering system. The commercially developed ceria-based oxide slurry, silica-based oxide slurry, and alumina-based tungsten slurry were used as CMP slurry. Nonuniformities of all slurries coincided with stability standards of less than 5%. Silica slurry had the highest removal rate among three different slurries. In addition, the particle size analysis showed that silica slurry had an abrasive with the largest average particle size of the three. Based on the atomic force microscopy analysis of thin film topographies and root mean square values, silica slurry has excellent properties that allow the application of SnO2 thin films as gas sensor materials.