The particle size distribution of abrasives has a serious impact on the polishing effect of copper film.In the polishing process of abrasives with a single particle size,it is difficult to accurately evaluate the effect of some large or small abrasives.To solve this problem,different abrasive mixtures with similar particle sizes (40 nm,60 nm and 80 nm) were used to characterize the effect of particle size dispersion on copper film polishing.The effect of polishing liquid mixed with single abrasive,2 and 3 abrasive sizes on the polishing of silicon through hole copper film was studied.The results show that the polishing rate and surface quality of copper film can be improved by mixing abrasive with different particle sizes at the same mass fraction.When two kinds of abrasives are mixed,the larger the particle size difference,the faster the polishing speed.The polishing rate and polishing surface quality of abrasives mixed with three particle sizes are better than that of single particle size and two particle sizes.When the ratio of 40 nm,60 nm and 80 nm abrasives is 1∶3∶2,the polishing effect is the best.The physical model of abrasive distribution between copper sheet and polishing pad was established,the mechanism of increasing the removal rate of copper film with mixed abrasive was revealed,and the contact area between abrasive and copper sheet was calculated.