Manufacturing method of a light-emitting device

Abstract

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.

What is claimed is: 
     
         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.