| 摘要 |
PROBLEM TO BE SOLVED: To provide a wafer processing method by which a wafer having a plurality of devices formed on a surface of a single crystal substrate with an off-angle can be surely divided along a scheduled division line.SOLUTION: The wafer processing method performs: a step of setting the number (NA) of apertures of a condensing lens so that values determined by dividing the number (NA) of apertures of the condensing lens that condenses pulse laser beams by a refractive index (N) of a single crystal substrate are in a range of 0.05-0.2; a shield tunnel forming step of radiating pulse laser beams along a schedule division line with a condensing spot of the pulse laser beams positioned at a desired position on a backside of the single crystal substrate, and forming a shield tunnel 25 constituted of a narrow hole and an amorphous material shielding the small hole from the condensing spot positioned in the single crystal substrate along the scheduled division line; and a wafer dividing step of applying external force to a wafer 2 subjected to the shield tunnel forming step and dividing the wafer 2 into individual devices 23 along the scheduled division line having the shield tunnel 25 formed.SELECTED DRAWING: Figure 6 |
