A Comprehensive Investigation of Depth Filter Functionality for a Colloidal Silica Slurry Used for Semiconductor Manufacturing Process

We report a comprehensive study on depth filter functionality by using a slurry, colloidal silica, used for chemical mechanical polishing process in semiconductor manufacturing. We show that the depth filters with nominal pore size ranging from 0.1 μm to 0.5 μm selectively reduces the concentration of `large' particles up to 80%, and maintains other critical properties of slurry including solid content ratio, mean diameter of particles, pH, zeta potential, and conductivity. Furthermore, we find the particle size-dependent filter efficiency, and the stable and allowable pressure drop across the filters. The depth filtration efficiently reduces the large particle concentration in slurry, and thus could be useful for suppressing the associated manufacturing defects such as micro-scratches and pits on the polished wafers.