Experimental study regarding the surface roughness of circular crystal wafers sliced by a multi-wire saw with reciprocating and rocking functions

Abstract

Abstract At present, wire sawing technology is the primary slicing method used for certain brittle materials, including monocrystalline silicon, sapphire, and silicon carbide. The surface quality of the sawn wafers significantly impacts subsequent machining processes, such as grinding and polishing. A theoretical model was developed to predict the amount of material removed per unit length of wire during the slicing of circular workpieces by a wire saw with reciprocating and rocking functions. Experiments were conducted during this study in which crystal ingots were sliced using a multi-wire saw, and the amount of material removed per unit length of wire was determined at different cutting positions on the workpiece cross-section. The surface roughness of each crystal wafer was measured systematically. The experimental results revealed that the surface roughness values measured at different points at the same y-coordinate position on a single wafer were approximately equal. However, the surface roughness was greatest on both the initial and final cutting edges and gradually decreased toward the wafer center. The surface roughness was also greatest for the wafer cut nearest to the new wire side, though it gradually decreased for wafers cut nearer to the center of the workpiece and remained relatively consistent from the middle wafer to the wafer cut nearest to the used wire side. The results also indicated that both the material removed per unit length of wire and the surface roughness of the wafer decreased with increases in the wire speed. The relationship between the material removed per unit length of wire and the surface roughness was approximately linear. When the material removed per unit length of wire was set to 0.00333 mm³/m, the average wafer surface roughness was 0.45 µm.