| 摘要 |
<P>PROBLEM TO BE SOLVED: To cut dividing grooves in a wafer by a laser beam, to remove an opaque solid material that is melted and solidified again, and to obtain separate group III nitride compound semiconductor light emitting devices. <P>SOLUTION: A group III nitride compound semiconductor element layer 2 is formed on a substrate 1, an adhesive sheet 3 is pasted, and a wafer is turned over (a). When dividing grooves are provided in a lattice (d) on the rear surface of the wafer by laser irradiation, the dividing grooves are formed in a state where the material M that is melted and solidified again is present in the grooves (b). Blast processing is carried out until the side faces LS of the dividing grooves are exposed (c). Thereafter, the wafer is divided into separate devices by roller breaking or the like. Figure (e) is an enlarged view of a part A shown in Figure (b) which shows the surface condition of the wafer that is not subjected to blast processing yet, the melted and solidified material M is attached to the surface of the dividing groove, and a melted, flew, and solidified material Ab is uniformly attached on the rear surface of the substrate 1. As shown in Figure (f), when the substrate 1 is subjected to blast processing until the side face LS of the dividing groove is exposed, the rear surface of the substrate 1 is partially ground down and roughened into a rough rear surface BS. Therefore, the nitride compound semiconductor light emitting device can be improved in light extraction properties. <P>COPYRIGHT: (C)2004,JPO |
