A detection method of stick-slip state on wafer transfer surface and its sensor design

In order to perceive stick-slip on during wafer transfer process, in this paper, a detection method was proposed and a force sensor basing on electromagnetic principle was applied to achieve this function. Through kinetic analysis, we chose second derivative of friction as detection judgment because friction varies in a high frequency within stick-slip state. Basing on the kinetic characteristics of force sensor, we added a circuit with the function of first derivation to obtain linear output of judgment. The results of model identification experiment indicate that second derivation function can be achieved within 2 kHz. In wafer transfer experiment, this sensor gave out a large amplitude and high frequency output when stick-slip appeared, which verified the effectiveness of this method for stick-slip detection in wafer transfer system.