Effects of Slurry Distribution using Diaphram and Centrifugal Pumps on the Defectivity in a Cu CMP Process

Abstract

Slurry health has been shown to impact defectivity in the chemical mechanical planarization (CMP) process. Improper mechanical handling is known to form large agglomerates in CMP slurries that can lead to increased scratching of the surface. The foremost cause of slurry damage occurs from shear stresses placed on the slurry particles as they pass through the motive force in a distribution system. This paper is a study of two common slurry pumping methods and their contribution to post CMP micro-scratch defects measured on TEOS, Black Diamond l (BD l), Cu blanket wafers, and low-k/Cu integrated patterned wafers. The two specific slurry handling methods studied were the recirculation of slurry in a distribution system by positive displacement (diaphragm) pumps and bearingless centrifugal pump systems.