Investigation of the abrasive removal depth for bowl-shaped structure of sapphire wafer under compensated chemical mechanical polishing

摘要

The paper establishes a new compensated chemical mechanical polishing theoretical model of abrasive removal depth of sapphire wafer polished by polishing pad with cross pattern. For the theoretical model, it combines the theoretical model of calculating number of polishing times by using binary image dividing with the contact model of multiple abrasive particle in single pixel. Regarding the theoretical model, first of all, the concept of binary image pixel dividing is applied, and the number of polishing times of each time increment is calculated. After that, according to different contact models of multiple abrasive particle in single pixel, the paper estimates the contact force between a single abrasive particle and wafer. Based on the contact force, the paper calculates the penetration depth on sapphire wafer surface of a single abrasive particle in each unit of time increment. Through the abrasive removal depth model of polishing wafer established by the paper, the paper simulates a polishing pad with cross pattern to polish the sapphire wafer of bowl-shaped structure and obtains a certain number of polishing times and abrasive removal depths within a certain period of time. The paper also carries out chemical mechanical polishing experiment, and applies the experimental results in order to verify the rationality of the abrasive removal depth model of wafer polishing established by the paper.