METHOD FOR MANUFACTURING SEMICONDUCTOR LIGHT EMITTING ELEMENT
Provided is a method for manufacturing a semiconductor light emitting element, by which semiconductor light emitting elements having excellent light extraction efficiency can be manufactured at high yield. The method includes: a grinding step for grinding a surface to be ground ( 103 ) of a substrate ( 11 ) of a wafer having the substrate ( 11 ) and group III nitride semiconductor layers composed of a multilayer structure of a group III nitride semiconductor formed on the substrate ( 11 ); a polishing step for adjusting surface roughness (Ra) of the ground surface ( 103 ) of the substrate ( 11 ) ground by the grinding step to be 3 nm to 25 nm; a laser processing step for providing processed modified portions ( 41, 42 ) inside of the substrate ( 11 ) by applying a laser beam (L 2 ) along a cut-planned line for dividing the substrate ( 11 ) from the side of the ground surface ( 103 ) of the substrate ( 11 ) having the surface roughness (Ra) adjusted by the polishing step; and a dividing step for dividing the substrate ( 11 ) provided with the processed modified portions ( 41, 42 ) by the laser processing step, along the processed modified portions ( 41, 42 ) and the cut-planned line.
1 . A method for manufacturing a semiconductor light emitting element having group III nitride semiconductor layers, the method comprising:
a grinding step for grinding a surface to be ground of a substrate of a wafer having the substrate and the group III nitride semiconductor layers composed of a multilayer structure of a group III nitride semiconductor formed on the substrate;
a polishing step for adjusting surface roughness Ra of the ground surface of the substrate ground by the grinding step to be 3 nm to 25 nm;
a laser processing step for providing a processed modified portion for an inside of the substrate by applying a laser beam along a cut-planned line for dividing the substrate from the side of the ground surface of the substrate having the surface roughness Ra adjusted by the polishing step; and
a dividing step for dividing the substrate along the processed modified portion and the cut-planned line, the substrate being provided with the processed modified portion by the laser processing step.
2 . The method for manufacturing a semiconductor light emitting element according to claim 1 , wherein the laser processing step provides a plurality of the processed modified portions discontinuously in a thickness direction of the substrate.
3 . The method for manufacturing a semiconductor light emitting element according to claim 1 , wherein the laser processing step provides the processed modified portion in a range of two thirds of the inside of the substrate in a thickness direction from the side of the ground surface.
4 . The method for manufacturing a semiconductor light emitting element according to claim 1 , wherein in the laser processing step the substrate is irradiated with a pulse of the laser beam.
5 . The method for manufacturing a semiconductor light emitting element according to claim 1 , wherein in the dividing step the substrate is divided to turn a divided surface of the substrate into a rough surface.
6 . The method for manufacturing a semiconductor light emitting element according to claim 1 , further comprising a dividing-groove forming step for forming a dividing groove in the substrate by applying a laser beam along the cut-planned line from the side of the group III nitride semiconductor layers formed on the substrate.
7 . The method for manufacturing a semiconductor light emitting element according to claim 1 , further comprising a substrate processing step for forming a plurality of convex portions on a surface of the substrate in advance.
8 . The method for manufacturing a semiconductor light emitting element according to claim 7 , further comprising a buffer layer forming step for forming a buffer layer composed of a group III nitride semiconductor by sputtering on the surface of the substrate having the convex portions formed thereon.
9 . The method for manufacturing a semiconductor light emitting element according to claim 1 , wherein the substrate is selected from any one of sapphire and silicon carbide.
10 . The method for manufacturing a semiconductor light emitting element according to claim 1 , wherein the group III nitride semiconductor layers of the wafer are composed of a multilayer of an n-type semiconductor layer, a light emitting layer and a p-type semiconductor layer that each includes a group III nitride compound semiconductor.
11 . The method for manufacturing a semiconductor light emitting element according to claim 1 , wherein the substrate has a maximum diameter of about 100 mm or more.
12 . A semiconductor light emitting element manufactured by the method for manufacturing a semiconductor light emitting element according to claim 1 .