Patent ID: 7947574
Filing Date: 2011-05-24
Classification: B23K,B28D

Abstract:
1. A method for manufacturing a semiconductor chip, the method of irradiating a substrate having a front face formed with a laminate part including a plurality of functional devices with laser light while locating a light-converging point within the substrate so as to form a modified region to become a start point for cutting within the substrate along a line to cut of the substrate, the method comprising the steps of: bonding a protective tape to the object so as to cover the laminate part; irradiating the substrate with the laser light while using a rear face of the substrate as a laser light entrance surface so as to form a first modified region along the line to cut at a position where a distance between the front face and an end part on the front face side is 5 μm to 15 μm; irradiating the substrate with the laser light while using the rear face as a laser light entrance surface so as to form at least one row of a second modified region along the line to cut at a position between the first modified region and the rear face of the substrate; bonding an expandable tape to the rear face; and expanding the expandable tape so as to start fractures from the modified regions, thereby cutting the substrate and laminate part along the line to cut, wherein the substrate is a semiconductor substrate, and the first and second modified regions include a molten processed region, and the light-converging point of the laser light is located at a position distanced by 50 μm to [(substrate thickness)×0.9] μm from the rear face or located at a position distanced by 20 μm to 110 μm from the rear face when forming the second modified region.