In situ wireless measurement of grinding force in silicon wafer self-rotating grinding process

Abstract

Grinding force is a crucial factor that affects the machining accuracy, wheel wear and the material removal efficiency for precision machining of semiconductor materials under nanometer accuracy. However, due to the complex rotational motion of both the grinding wheel and wafer workpiece, in situ measurement of the grinding force in wafer self-rotating grinding is still a big challenge. In this paper, a novel grinding force measurement method in silicon wafer grinding process is developed. The method is achieved by embedding four thin film force sensors into a self-designed force measurement device and real-time monitoring through wireless signal transmission. Based on this method, the grinding force under 5 groups of process parameters are measured. For the first time, the variations of grinding force during the whole grinding process are revealed real-timely. Effects of process parameters, i.e. spindle rotational speed and feed rate, on grinding force are investigated, and the parameters are also optimized based on the theory of specific grinding energy. The test results show that the force measurement method has the advantages of high precision, reliable and convenient implementation.