Prediction and verification of wafer surface morphology in ultrasonic vibration assisted wire saw (UAWS) slicing single crystal silicon based on mixed material removal mode

Abstract

Monocrystalline silicon is one of the most important semiconductor materials, widely used in chip manufacturing, solar panels. Slicing is the first step in making chips and the surface quality of silicon wafers directly affects the quality of later processing and accounts for a large proportion in the chip manufacturing cost. Ultrasonic vibration assisted wire saw (UAWS) is an effective sawing process for cutting hard and brittle materials such as monocrystalline Si, which can significantly improve the surface quality of silicon wafers. In order to further study the formation mechanism of the surface morphology of single crystal silicon sliced by UAWS, a new model for prediction of wafer surface morphology in UAWS slicing single crystal silicon based on mixed material removal mode is presented and verified in this paper. Firstly, the surface model of diamond wire saw tool is established by equal probability method. Then according to the equation of transverse vibration dynamics about the wire saw with ultrasonic excitation, the trajectory equation of arbitrary abrasive particles on the surface of wire saw is derived and analyzed. Thirdly, a new model for prediction of the wafer surface morphology based on mixed material removal mode is presented, which can be used to predict the wafer surface morphology of single crystal silicon sliced by UAWS. Finally, the prediction model is verified by UAWS slicing experiment, and the effects of slicing parameters such as wire saw speed, feed speed and workpiece rotate speed on the surface quality of silicon wafer were studied. It shows that the predicted wafer surface morphology and the experimental wafer surface morphology are similar in some characteristics, and the average error between the experimental and the theoretical values of the wafer surface roughness is 11.9%, which verifies the validity of the prediction model.

Recent Advances in Precision Diamond Wire Sawing Monocrystalline Silicon

“…Ultrasonic vibration-assisted DWS (UV-DWS) is a composite processing technology that combines ultrasonic vibration with fixed abrasive DWS [ 153 ]. The ultrasonic vibration-assisted machining process makes it possible to cut a variety of hard materials with conventional diamond [ 154 ].…”