Investigation On The Final Polishing Of Silicon Substrate In ULSI

The demension of silicon substrate become more and more biger and the characteristic demension go diminishing with the development of 1C. The demand of the wafer's quality become higher too. The result of the final polishing determines the quality of silicon substrate for the final polishing is the last step in the polishing. In this paper, the mechanism and dynamics process of silicon polishing are systematically analyzed. A lot of experiences and analysises are done to resolve the problems of final polishing, such as: metallic ions contamination, partical adsorption, polishing haze, etc. The parameters that affect the remove rate and polishing quality are analyzed deeply, and the optimal conditions have been reached. The choices of components in the final polishing slurry, specially alkali, surfactant and chelating agent have been discussed. For their permeability and dispersion, the surfactants accelerates mass transfer of reactants and reaction productions. So the polishing rate is improved. The metallic ions are reduced for existing of chelating agent without sodium ions. The forming factors, the examining and reloving ways of damages of silicon surface have been studied, and the forming cause of polishing haze have been gained, the polishing haze is eliminated by modulating the arts of the final polishing.