The present invention provides a method of reducing micro-particle adsorption effects during a CMP process, to thereby reduce micro-particle adsorption effects on a surface of a semiconductor wafer comprising a silicon nitride layer. The method uses polishing slurry containing anionic surfactant to change the zeta potential of the silicon nitride. Therefore, during the CMP process, the surface of the silicon nitride layer and the micro-particles bare the same type of charges, so as to reduce micro-particle adsorption effects on the surface of the semiconductor wafer.