Research on Si (100) crystal substrate CMP based on FA/O alkaline slurry

For the advanced IC technology nodes, the surface quality of the polished silicon substrate surface becomes more and more critical. Haze is used to characterize extremely small pits scatter light disproportionately at the angle of measurement (90°), and Haze collected on full wafer scale with high throughput is the key CMP output parameter in an advanced CMP process. In this study, the influence of surface defects especially scratch, particle contamination, and surface roughness on Haze was investigated. The results indicate scratch and particle contamination take some influence on Haze, and Haze increases quickly with the increasing of surface roughness. So it can be concluded that surface roughness is the key affecting factor of Haze. In addition, the influence of FA/O surfactant in the alkaline slurry on Haze was studied. The results show FA/O surfactant can effectively decrease Haze. Finally, the advantages of the FA/O alkaline slurry were exhibited by the contrast experiments. A much lower level of metallic ions residual and a much better WIWNU were gotten for silicon wafers polished by FA/O alkaline slurry than that by the commercial one. Hence, the FA/O alkaline slurry provides a high quality silicon wafer surface. The results are helpful for researching the silicon CMP as well as the other materials.