PROCESSING METHOD AND LASER PROCESSING APPARATUS OF SAPPHIRE WAFER

摘要

PROBLEM TO BE SOLVED: To form a plasm layer well regardless of the difference in the crystal defect of sapphire wafer.SOLUTION: A processing method of sapphire wafer has a step of test processing a modified layer by irradiating the circumferential surplus area of a sapphire wafer on a chuck table with a laser beam under a predetermined laser processing condition, a step of selecting an optimum laser processing condition corresponding to the modified layer formation rate during laser processing under a predetermined processing condition from relevant data, by calculating the modified layer formation rate from a captured image of the modified layer in the circumferential surplus area of the sapphire wafer, and a step of forming a modified layer along scheduled dividing lines, by irradiating a laser beam along the scheduled dividing lines of the sapphire wafer under an optimum laser processing condition.SELECTED DRAWING: Figure 2