Patent ID: 8685838
Filing Date: 2014-04-01
Classification: B23K,B28D,C03B,Y02P

Abstract:
1. A laser processing method comprising the steps of: irradiating a wafer-like object to be processed with laser light while the object is secured to a surface of an expandable holding member, the irradiating of the object comprising locating a light-converging point within the object, so as to form a modified region within the object along each of a plurality of cutting lines forming a grid of intersecting cutting lines, wherein each modified region serves as a cutting start region located within the object at a predetermined distance inside of a laser light entrance surface of the object; irradiating the object with laser light absorbable by the object along each of the cutting lines after the step of forming each cutting start region, so as to change each cutting start region so that it is easier to generate a fracture from the cutting start region as compared to prior to the irradiating step performed after the step of forming each cutting start region, thereby generating a fracture extending from each cutting start region that reaches the surface of the object to which the expandable holding member is attached, without generating any fracture reaching an opposing surface of the object located opposite the surface of the object to which the expandable holding member is attached; and expanding the holding member after the irradiating step performed after the step of forming each cutting start region, so as to cut the object into cut portions and to separate the cut portions of the object from each other.