Method for manufacturing high efficiency light-emitting diodes

1. A method for manufacturing a light-emitting device comprising the steps of:

cutting a substrate by a laser beam to form a cavity in the substrate and generate a by-product directly on the substrate by the cutting; and

removing the by-product by a chemical solution containing an acid under a predetermined cleaning temperature, wherein the by-product includes a first by-product and a second by-product that are removed under the predetermined cleaning temperature that is not lower than 250° C.

2. The method for manufacturing a light-emitting device according to claim 1 , further comprising forming a light-emitting stack on the substrate, wherein the step of forming the light-emitting stack comprises:

forming a first semiconductor layer on the substrate;

forming a semiconductor light-emitting layer on the first semiconductor layer; and

forming a second semiconductor layer on the semiconductor light-emitting layer;

removing a portion of the second semiconductor and the semiconductor light-emitting layer thereby exposing a portion of the first semiconductor layer; and

forming a second electrode on the second semiconductor and forming a first electrode on the exposed the first semiconductor layer.

3. The method for manufacturing a light-emitting device according to claim 1 , wherein the step of forming the first semiconductor layer on the substrate is after the step of cutting the substrate by the laser beam.

4. The method for manufacturing a light-emitting device according to claim 1 , wherein the cavity comprises a cutting line.

5. The method for manufacturing a light-emitting device according to claim 1 , wherein the chemical solution comprises phosphoric acid.

6. The method for manufacturing a light-emitting device according to claim 5 , wherein the chemical solution comprises sulfuric acid.

7. The method for manufacturing a light-emitting device according to claim 1 , further comprising forming a protective layer on the substrate before the cutting.

8. The method for manufacturing a light-emitting device according to claim 1 , wherein the cavity and the light-emitting stack are on opposite sides of the substrate.

9. The method for manufacturing a light-emitting device according to claim 1 , wherein the cavity and the light-emitting stack are on the same side of the substrate.

10. The method for manufacturing a light-emitting device according to claim 1 , wherein the substrate comprises a material selected from the group consisting of sapphire, SiC, GaN, AlN, ZnO and MgO.

11. A method for manufacturing a light-emitting device comprising the steps of:

cutting a substrate by a laser beam to form a cavity in the substrate and generate a by-product directly on the substrate by the cutting; and

removing the by-product by a chemical solution containing an acid under a predetermined cleaning temperature,

wherein the by-product comprises a first by-product and a second by-product capable of being removed at a cleaning temperature unable to remove the first by-product.

12. The method for manufacturing a light-emitting device according to claim 11 , wherein the first by-product and the second by-product are removed under the predetermined cleaning temperature not lower than 250° C.

13. The method for manufacturing a light-emitting device according to claim 11 , wherein the first by-product is directly in the cavity and the second by-product is directly on the substrate other than the cavity.

14. The method for manufacturing a light-emitting device according to claim 1 , wherein the cavity comprises a plurality of cutting lines defining a plurality of chip regions.

15. The method for manufacturing a light-emitting device according to claim 1 , further comprising a grinding step to thin the substrate.

16. The method for manufacturing a light-emitting device according to claim 1 , further comprising a polishing step to flatten the substrate before the cutting.

17. The method for manufacturing a light-emitting device according to claim 2 , further comprising a breaking step to separate the substrate with the light-emitting stack into chips.

18. The method for manufacturing a light-emitting device according to claim 17 , wherein at least one side wall of one of the chips is rough.

19. The method for manufacturing a light-emitting device according to claim 1 , wherein the substrate has a diameter between 2 inches and 8 inches.