MANUFACTURING METHOD OF A LIGHT-EMITTING DEVICE
A method for manufacturing a light-emitting device includes steps of: providing a substrate comprising an upper surface and a lower surface opposite to the upper surface; processing the upper surface to be an uneven surface; forming a light-emitting structure on the upper surface of the substrate; and forming a hole through the substrate by radiating a coherent laser beam to the lower surface of the substrate for a predetermined time; wherein the band gap energy of the coherent laser beam is higher than the band gap energy of the substrate thereby the substrate is etched away by the laser beam.
1 . A method for manufacturing a light-emitting device comprising steps of:
providing a substrate comprising an upper surface and a lower surface opposite to the upper surface;
processing the upper surface to be an uneven surface;
forming a light-emitting structure on the upper surface of the substrate; and
forming a hole through the substrate by radiating a first coherent laser beam to the lower surface of the substrate for a predetermined time;
wherein the band gap energy of the coherent laser beam is higher than the band gap energy of the substrate thereby a portion of the substrate is etched away by the first coherent laser beam.
2 . The method according to claim 1 , further comprising forming a conductive structure in the hole and electrically connected to the light-emitting structure, and forming a first contact on the lower surface of the substrate and electrically connected to the conductive structure after forming the hole.
3 . The method according to claim 1 , wherein a part of the first coherent laser beam becomes a non-coherent laser light during the predetermined time by being deflected from the direction of the first coherent laser beam.
4 . The method according to claim 1 , further comprising detecting the intensity of the non-coherent laser light by a photo-detector.
5 . The method according to claim 4 , further comprising stopping radiating the first coherent laser beam when the intensity of the non-coherent laser light is detected.
6 . The method according to claim 5 , wherein the intensity of the non-coherent laser light is detected when the first coherent laser beam reaches the uneven surface.
7 . The method according to claim 1 , wherein the uneven surface comprises a periodic pattern having plurality of pattern units having a pitch.
8 . The method according to claim 7 , wherein the pitch is the same as the wavelength of the coherent laser beam.
9 . The method according to claim 7 , wherein the pitch is smaller than the wavelength of the coherent laser beam.
10 . The method according to claim 7 , wherein the distance between two adjacent pattern units is smaller than the wavelength of the laser beam.
11 . The method according to claim 5 , further comprising cleaning the hole by a second coherent laser beam after stopping radiating the coherent laser beam.
12 . The method according to claim 1 , wherein the step of forming the light-emitting structure comprising steps of forming a buffer layer on the uneven surface of the substrate, forming a first semiconductor layer on the buffer layer, forming an active layer on the first semiconductor layer, and forming a second semiconductor layer on the active layer.
13 . The method according to claim 1 , further comprising forming a reflective layer on the lower surface of the substrate.
14 . The method according to claim 1 , wherein the method is performed in an MOCVD chamber.