Next Generation Composite, Rigid Filter for Chemical Mechanical Planarization

Chemical Mechanical Planarization (CMP) slurries are formulated to provide a narrow particle size distribution within a chemically active carrier for chemical and mechanical material removal during the construction of integrated circuits. The role of CMP filtration is to reduce the Large Particle Counts (LPC) without affecting the particle size distribution, solids content or the chemistry of the slurry. Two different filter structures were compared in this study. One consisted of Melt Blown Fibers (MBF). The other consisted of a Composite, Rigid Filter (CRF) matrix. LPC reduction can be achieved at significantly high flow rates and low pressure drop with CRF. This was not the case with MBF. These improvements were attributed to physical properties of the materials of construction used in the CRF. Specifically, there is a distinct advantage in surface energy and rigidity. The elevated pressure drop experienced across the MBF filter may lead to slurry property changes, including shear stress and agglomeration.