Laser cutting by forming a modified region within an object and generating fractures

A method of manufacturing a semiconductor device formed using a laser processing method for processing an object to be processed, the object comprising a main surface onto which laser light is irradiated and a surface opposite the main surface, and the object comprising semiconductor material in which at least one semiconductor device is formed, the manufacturing method comprising:

• irradiating the object to be processed with laser light so as to form a plurality of first light-converging points of the laser light each at a location within the object spaced from the main surface and the opposite surface and each aligned with one of a plurality of first lines, extending in a first direction, along which the object is intended to be cut;
• forming at least one first modified region within the object at the locations of the first light-converging points so as to form at least one first modified region aligned with each of the plurality of first lines along which the object is intended to be cut, such that after formation of the at least one first modified region, the object comprises the at least one first modified region and a non-modified region with at least a portion of the non-modified region existing at least one of above and below each first modified region such that each first modified region does not extend continuously through the object from the main surface to the opposite surface, the forming of the at least one first modified region being performed so that the at least one first modified region is not formed in the main surface of the object, and the at least one first modified region functioning as at least one starting point for generating a fracture therefrom to cause the object to be cut along the first lines along which the object is intended to be cut;
• irradiating the object with laser light so as to form a plurality of second light-converging points of the laser light each at a location within the object spaced from the main surface and the opposite surface and each aligned with one of a plurality of second lines, extending in a second direction crossing the first direction, along which the object is intended to be cut;
• forming at least one second modified within the object at the locations of the second light-converging points so as to form at least one second modified region aligned with each of the plurality of second lines along which the object is intended to be cut, such that after formation of the at least one second modified region, the object comprises the at least one second modified region and a non-modified region with at least a portion of the non-modified region existing at least one of above and below each second modified region such that each second modified region does not extend continuously through the object from the main surface to the opposite surface, the forming of the at least one second modified region being performed so that the at least one second modified region is not formed in the main surface of the object, and the at least one second modified region functioning as at least one starting point for generating a fracture therefrom to cause the object to be cut along the second lines along which the object is intended to be cut;
• and
• cutting the object into a plurality of semiconductor chips, each comprising at least one semiconductor device, along the first and second lines by using the at least one first and second modified regions as starting points for generating fractures therefrom to cause cutting of the object, with such cutting resulting in the manufacture of at least one manufactured semiconductor device.