The compression deformation and particles removal of PVA brushes during the post-CMP cleaning process

Abstract

In advanced wafer manufacturing processes, a wet cleaning system (wet in dry out) integrated with chemical mechanical polishing equipment is the primary form of post-chemical-mechanical polishing (CMP) cleaning. This pioneering study addresses the quantitative description of the contact between a polyvinyl alcohol (PVA) sponge brush and the wafer surface and establishes a relationship between the compression deformation as a function of the pressure on the wafer surface to achieve precise control of the contact between the brush and the wafer. The physical properties of the three types of PVA sponge brushes, namely, porosity, saturated water absorption, and pore change rate, were analyzed, and the effect of particle removal was explored. Finally, the effect of the brush on removing the residual polishing liquid from the wafer surface under different compression deformation conditions was studied, and its internal mechanism was explained. A ‘√’ curve was observed between the compression deformation (stress) and particle removal effect. When the compression deformation (stress) is 0.5 mm (35.11 g), the 26 nm particles on the wafer surface after post-CMP cleaning can reach less than 10ea.