Working Condition Optimization in Double-Sided Chemical-Mechanical Polishing Process
In the process of double-sided chemical-mechanical polishing,the relative motion state between the wafer and the polishing pad is a key factor affecting the processing quality of the wafer surface,especially the global flatness.In order to improve the global flatness of the wafer surface in the process of double-sided chemical-mechanical polishing,a mathematical model was constructed on the basis of the basic dimensional structure of double-sided chemical-mechanical polishing,and the mathematical model was effectively simplified by replacing the velocity with the velocity squared.Then,Python software was used to simulate the motion state of the wafer relative to the upper polishing pad and lower polishing pad,and the variable β was introduced to quantify the global flatness of the wafer surface.The simulation results show that the global flatness of the wafer surface is determined by the rotation angular velocities of the upper and lower polishing pads,and the revolution and rotation angular velocities of the planetary wheel when the mechanical structure is constant.The influence of the rotation angular velocities of the upper and lower polishing pads on the global flatness of the wafer surface is stronger than that of the revolution and rotation angular velocities of the planetary wheel,and a working condition optimization strategy is further proposed.