Adhesion and removal of silica and alumina slurry particles during Cu CMP process

Abstract

This study aims to investigate the interaction forces between slurry particles and wafer surfaces during the Cu CMP. The interaction forces between slurry particles and Cu surfaces are measured and calculated. The DLVO theory was used to calculate these forces by measuring the zeta potentials of the particles and the surfaces. The interaction force was obtained directly by measuring the force on the particles as a function of the distance between the particle and the surface. Likewise, the magnitude of particle contamination on the wafers was measured by field-emission scanning electron microscope after the wafers were polished. The weakest repulsion force was measured between particles and Cu surface at pH3. Similarly, the highest number of particles was observed on Cu surfaces in the pH3 solution after they were polished.