Abstract：In order to obtain the effects of retaining ring to the contact pressure distributions in the chemical mechanical polishing（CMP）of silicon wafer

based on the practices of CMP with a retaining ring

the mechanism model and boundary conditions on CMP processes are set up. Then the contact pressure distribution are calculated and analyzed by the use of ANSYS

and are investigated by polishing experiments. At last

the contact pressure distributions between silicon wafer and polishing pad and the effects of the retaining ring on it are obtained

.In conclusion

in CMP

the contact pressure distribution is non-uniform and the pressure in the outside borderline of silicon wafer is the maximal

which generate the flatness errors and the subsiding of the outside edge of wafer. When the geometrical sizes and the load ratio of the retaining ring to silicon wafer are chosen properly

the uniformity of the contact pressure distribution can be improved and the available region flatness of wafer surface will become better.