Abstract
We produced the diamond saw wire using the commercial lead-free solder as a fixing material of diamond abrasive particles, and sliced sapphire ingots into wafers with the saw wires.
The co-drawn brass coated piano wire was adopted as a core material. Electroless Ni-P coated diamond abrasive particles were employed to enhance adhesion between the solder and diamond abrasive particle. We developed the equipment that performs solder coating on wire, temporary fitting of diamond abrasive particles on wire, and final fixing, in one continuous operation. We were able to produce saw wires as long as around 2 km. By using these saw wires we succeeded in slicing a sapphire ingot of 50.8 mm diameter into 50 wafers at a time. However, the average thickness of the wafers tended to be thinner toward the winding side of the wire saw machine. The total thickness variation (TTV), the maximum surface waviness (WT) and the maximum surface roughness (RZ) tended to increase toward the winding side. During the slicing process of ingot, the load on the saw wire maximized when the wire had moved a considerable distance away from the center of the ingot.
