Surface Shaping Using Chemical Mechanical Polishing

Abstract

In this study we have investigated the phenomena of edge rounding in chemical mechanical polishing (CMP) of patterned surfaces for its potential for creation of different topographies. Hexagonal array of SiO2 cylindrical pillars with 20 µm diameter, 1 µm spacing and ∼1 µm height was polished under different conditions to form rounded surfaces. The effect of CMP variables: pad and pressure were studied by polishing these patterned wafers with Politex and IC1000/Suba IV stacked pad at different pressures. CMP with soft Politex pad led to formation of spherical curvature with radius of curvature dependent on pressure and polishing duration. Radius of curvature as small as 300 µm was obtained at 2.5 psi after polishing for 2 min using Politex pad. The surface evolution dynamics during polishing has been discussed based on contact mechanical model for CMP.