Microcontact mechanism in silicon wafer self-rotating grinding based on force decomposition

Carrying out silicon wafer self-rotating grinding using a cup-type diamond grinding wheel is a typical ultra-precision machining technique of silicon wafers. Studying the mechanism of the self-rotating grinding is the basis of the processing. The research takes the microcontact between the micro-element in the grinding wheel and the silicon wafer extracted during the steady ductile-regime grinding as the object and builds a mechanical model. On this basis, the research investigates the microscopic mechanism of the self-rotating grinding using the force decomposition method. The force decomposition in the normal direction using the Hertz theory in contact mechanics and the cavity model obtained the distributions of the load and stress on the silicon wafer in the elastic and plastic contact, as well as the corresponding stress distribution on the micro-element in the grinding wheel. The force decomposition in the tangential direction based on the microscopic friction theory yields the sliding friction. The superposition of normal and tangential forces reveals the overall distribution of microcontact stress. The analysis results are validated by comparing with corresponding experimental and simulation results.