Patent ID: 7547613

Claim:
A laser processing method comprising: irradiating an object which is fixed on a flexible sheet to be processed with laser light such that a light converging point of the laser light is located at a position located within the object and spaced from a surface of the object by a predetermined distance, along each of a plurality of first lines along which the object is intended to be cut and extends along a first direction, to form first modified regions at least within the object along the first line along which the object is intended to be cut serially, and irradiating the object with laser light such that a light converging point of the laser light is located at a position located within the object and spaced from a surface of the object by a predetermined distance along each of a plurality of second lines along which the object is intended to be cut and extend along a second direction crossing the first direction, to form second modified regions at least within the object along the second lines serially, each of the first and second modified regions having a maximum length in a thickness direction of the object, a length of each of the first modified regions in a direction along the first line along which the object is intended to be cut being larger than a length of the first modified region in a direction parallel to the surface of the object and perpendicular to the direction extending along the first line along which the object is intended to be cut, and a length of each of the second modified regions in a direction along the second line along which the object is intended to be cut being larger than a length of the second modified region in a direction parallel to the surface of the object and perpendicular to the direction extending along the second line along which the object is intended to be cut; and applying a stress to the object through the flexible sheet to divide the object into a plurality of chips along the first and second lines by functioning the first and second modified regions as starting points for cutting the object.