Light-emitting element and the manufacturing method thereof

Abstract

A light-emitting element comprises: a light-emitting stack configured to emit light; and a transparent substrate comprising an upper surface on which the light-emitting stack is formed, a bottom surface opposite to the upper surface, and a side surface connecting the upper surface with the bottom surface, wherein the side surface comprises a first arc portion, a second arc portion, and a transition portion between the first arc portion from and second arc portion.

1 . A light-emitting element, comprising:
 a light-emitting stack configured to emit light; and   a transparent substrate comprising an upper surface on which the light-emitting stack is formed, a bottom surface opposite to the upper surface, and a side surface connecting the upper surface with the bottom surface, wherein the side surface comprises a first arc portion, a second arc portion, and a transition portion between the first arc portion and the second arc portion.   
     
     
         2 . The light-emitting element according to  claim 1 , wherein the first arc portion is closer to the bottom surface than the second arc portion. 
     
     
         3 . The light-emitting element according to  claim 2 , wherein the transition portion is the outmost part of the side surface in a lateral direction. 
     
     
         4 . The light-emitting element according to  claim 3 , wherein the bottom surface comprises a first width, the transition portion of the side surface comprises a second width greater than the first width, and the upper surface comprises a third width smaller than the second width in a cross-sectional view. 
     
     
         5 . The light-emitting element according to  claim 3 , further comprising a reflective structure conformably formed on the bottom surface and the first arc portion of the side surface. 
     
     
         6 . The light-emitting element according to  claim 5 , wherein the reflective structure comprises a DBR. 
     
     
         7 . The light-emitting element according to  claim 1 , wherein the transition portion comprises a flat surface. 
     
     
         8 . The light-emitting element according to  claim 1 , wherein the transition portion comprises a vertex. 
     
     
         9 . The light-emitting element according to  claim 3 , wherein the side surface further comprises a plurality of arc portions and a plurality of transition portions separating the plurality of arc portions from each other. 
     
     
         10 . The light-emitting element according to  claim 1 , wherein the first arc portion comprises a curvature different from that of the second arc portion. 
     
     
         11 . The light-emitting element according to  claim 1 , wherein each of the first arc portion and the second arc portion comprises a negative curvature. 
     
     
         12 . The light-emitting element according to  claim 1 , wherein the transparent substrate is single-crystalline, and the light-emitting stack is an epitaxial structure. 
     
     
         13 . A method for manufacturing a light-emitting element, comprising the steps of:
 providing a wafer comprising an upper surface and a bottom surface;   forming a light-emitting stack on the upper surface of the wafer;   cutting the wafer from the bottom surface of the wafer to form a first arc portion by a water-jet laser having a first beam size;   cutting the wafer from the upper surface of the wafer to form a second arc portion by the water-jet laser having a second beam size; and   dividing the wafer and the light-emitting stack into a plurality of light-emitting dies, wherein one of the light-emitting dies comprises a side surface having the first arc portion and the second arc portion.   
     
     
         14 . The method according to  claim 13 , further comprising forming a plurality of trenches for dividing the light-emitting stack into multiple light-emitting blocks and exposing the upper surface of the wafer before cutting the wafer by the water jet laser. 
     
     
         15 . The method according to  claim 13 , wherein the wafer comprises a plurality of thinned portions after being cut by the water jet laser, and the method further comprises breaking the thinned portions to divide the wafer into the plurality of light-emitting elements. 
     
     
         16 . The method according to  claim 14 , wherein the step of dividing the wafer and the light-emitting stack into a plurality of light-emitting dies comprises continuing cutting the wafer by the water-jet laser to penetrate through the wafer completely. 
     
     
         17 . The method according to  claim 13 , wherein the water-jet laser comprises a water jet and a laser traveling in the water jet. 
     
     
         18 . The method according to  claim 13 , further comprising cutting the wafer from the bottom surface of the wafer to form a third arc portion by the water-jet laser having a third beam size different from the first beam size. 
     
     
         19 . The method according to  claim 18 , wherein the first beam size is bigger than one of the second beam size and the third beam size. 
     
     
         20 . The method according to  claim 13 , further comprising forming a reflective structure on the bottom surface and the first arc portion before dividing the wafer and the light-emitting stack into a plurality of light-emitting dies.