Light emitting diode substrate

1. A method of manufacturing a light emitting diode (LED) substrate, the method comprising:

providing a nano-patterned substrate having a plurality of convex portions and a plurality of first concave portions that are spaced apart from each other, wherein each first concave portion has a first depth (d1);

forming a plurality of protection structures to cover each of the convex portions, and exposing a bottom surface of each of first concave portions, wherein at least one of the protection structures is formed as a part of a sphere or an ellipsoid covering a top surface and a plurality of lateral surfaces of one of the convex portions; and

performing an anisotropic etching process to etch the bottom surface of each of the first concave portions which is not covered by the protection structure so as to form a plurality of second concave portions having a second depth (d2), wherein d2 is greater than d1, wherein at least one of the second concave portions is formed in a cone shape having a vertex, wherein the protection structures are formed using a maskless pendeo-epitaxy process.

2. The method of claim 1 , wherein the nano-patterned substrate is formed by a nanoimprint lithography.

3. The method of claim 1 , wherein a top portion of each of the convex portions has a first width (w1), each of the protection structures has a width (w2), and 0<w1<w2.

4. The method of claim 3 , wherein the protection structures are formed using a metal-organic chemical vapor deposition process.

5. The method of claim 4 , wherein the protection structures comprise GaN, InGaN or AlGaN.

6. The method of claim 2 , wherein the anisotropic etching process is performed using an inductively coupled plasma etching process.

7. The method of claim 6 , wherein process gas used in the inductively coupled plasma etching processing is a mixture of CF4, Cl2, and BCl3.

8. The method of claim 7 , wherein a ratio of components of the process gas is CF4:Cl2:BCl3=6:2:1.