Effect of Organic Additive on Surface Roughness of Polycrystalline Silicon Film after Chemical Mechanical Polishing

The effect of an organic additive on the surface roughness of a polycrystalline silicon (poly-Si) film was investigated by chemical mechanical polishing (CMP). The surface roughness of the polished poly-Si film was markedly reduced by adding 0.001 wt % hydroxyl ethyl cellulose (HEC) and then decreased slightly with further addition of HEC. We concluded that the reduction of surface roughness was attributed to the formation of a hydroplane layer on the poly-Si surface. Evidence of the hydroplane layer was verified by contact angle and X-ray photoelectron spectroscopy (XPS) measurements.