Abstract:
Disclosed are a light-emitting diode with a plurality of light-emitting elements and a method for manufacturing the same. The light-emitting diode includes: a plurality of light-emitting elements arranged on a substrate; a separation groove for separating adjacent light-emitting elements; an insulation material for filling at least a part of the separation; an electrical line for electrically connecting two adjacent light-emitting elements; and an insulation layer for insulating the electrical line from the side of the light-emitting elements. Each of the light-emitting elements includes a first conduction type semiconductor layer, an activation layer, and a second conduction type semiconductor layer, wherein the first conduction type semiconductor layer has an exposed upper surface obtained by removing the second conduction type semiconductor layer and the activation layer, the exposed upper surface being adjacent to the separation groove, and the electrical line being positioned upon the top of the insulation material. The separation groove is filled with the insulation material so as to prevent cutting of the electrical line and to increase the light-emitting area.

Description:
PRIORITY CLAIMS AND CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This patent document is a continuation-in-part of, and claims priority and the benefits of, a Patent Cooperation Treaty (PCT) application number PCT/KR2013/001495, entitled “LIGHT-EMITTING DIODE WITH A PLURALITY OF LIGHT-EMITTING ELEMENTS AND METHOD FOR MANUFACTURING SAME” and filed with the Korean Intellectual Property Office (KIPO) on Feb. 25, 2013, the contents of which is incorporated by reference in their entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    This patent document relates to a light emitting diode and a method for manufacturing the same. For example, the disclosed technology relates to a light emitting diode, which has a plurality of light emitting elements on a single substrate, and a method for manufacturing the same. 
       BACKGROUND 
       [0003]    An LED is a light emitting device having a lot of merits such as environmental friendliness, energy saving, long lifespan, and the like. However, since the LED is a direct current-driven device, the LED requires a converter in order to use AC power such as domestic AC power. The LED suffers from reduction in lifespan caused by shorter lifespan of the converter than that of the LED. In addition, the LED has a lot of problems such as 20% to 30% reduction in efficiency due to AC/DC conversion, deterioration in reliability due to use of the converter, environmental contamination, a large space for a product, design constraints, and the like. 
       SUMMARY 
       [0004]    Some implementations of the disclosed technology provides a light emitting diode including a plurality of light emitting elements, for example, a light emitting diode, which can prevent disconnection of a wiring and increase a light emitting area while ensuring electrical isolation between light emitting elements, and a method for manufacturing the same. 
         [0005]    In one aspect, a light emitting diode is provided to include: a substrate; a plurality of light emitting elements arranged on the substrate; an isolation trench isolating adjacent light emitting elements from each other; an insulation material filling at least a portion of the isolation trench; a wiring electrically connecting two adjacent light emitting elements to each other; and an insulation layer insulating the wiring from a side surface of the light emitting elements, wherein each of the light emitting elements includes a first conductivity-type semiconductor layer, an active layer, and a second conductivity-type semiconductor layer, the first conductivity-type semiconductor layer has an upper surface exposed by removing the second conductivity-type semiconductor layer and the active layer; the exposed upper surface adjoining the isolation trench; the wiring is disposed over an upper side of the insulation material, and the insulation material has an upper surface which is flush with or disposed below the exposed upper surface of the first conductivity-type semiconductor layer. 
         [0006]    Since the isolation trench is filled with the insulation material, there is no need to form the wiring in the isolation trench. Thus, since there is no need to form the isolation trench having a gently inclined sidewall, an entrance of the isolation trench can have a reduced width. Therefore, the light emitting diode can have a greater light emitting area than typical light emitting diodes. 
         [0007]    In some implementations, the wiring can electrically connect the upper surface of the first conductivity-type semiconductor layer of a first light emitting element to the second conductivity-type semiconductor layer of a second light emitting element. In some implementations, a portion of a side surface of the second light emitting element is covered with the wiring and has a gentler slope than the sidewall of the isolation trench. 
         [0008]    In some implementations, the isolation trench can be formed using dry or wet etching or using laser machining. In some implementations, the isolation trench can extend to an interior of the substrate. In some implementations, the isolation trench is formed by laser machining to have a decreasing width toward the substrate. 
         [0009]    In some implementations, the insulation material can include a polyimide or nanoparticles. 
         [0010]    In some implementations, the entrance of the isolation trench can have a width of 5 μm or less. In some implementations, the entrance of the isolation trench can have any width so long as the isolation trench can electrically isolate the light emitting elements. For example, the entrance of the isolation trench can have a width of 1 μm or more. In some implementations, the sidewall of the isolation trench can have a reverse slope. In some implementations, the insulation material includes nano-scale silica and a polyimide disposed over the silica. 
         [0011]    In some implementations, a portion of the insulation layer can cover an upper surface of the insulation material. 
         [0012]    In another aspect, a light emitting diode is provided to comprise: a substrate; a plurality of light emitting elements arranged on the substrate; an isolation trench isolating adjacent light emitting elements from each other; an insulation material filling at least a portion of the isolation trench; a wiring electrically connecting two adjacent light emitting elements to each other; and an insulation layer insulating the wiring from a side surface of the light emitting elements, wherein each of the light emitting elements includes a first conductivity-type semiconductor layer, an active layer and a second conductivity-type semiconductor layer, the first conductivity-type semiconductor layer has an upper surface exposed by removing the second conductivity-type semiconductor layer and the active layer, the exposed upper surface adjoining the isolation trench, the wiring is disposed over an upper side of the insulation material, and an air gap is disposed between the insulation material and the substrate. 
         [0013]    In some implementations, the insulation material includes nano-scale silica and a polyimide disposed over the silica. In some implementations, a portion of the insulation layer covers an upper surface of the insulation material. 
         [0014]    In another aspect, a method for manufacturing a light emitting diode includes: growing a first conductivity-type semiconductor layer, an active layer and a second conductivity-type semiconductor layer on a substrate; forming an etched recess exposing the first conductivity-type semiconductor layer by etching the second conductivity-type semiconductor layer and the active layer; forming an isolation trench to electrically isolate a plurality of light emitting elements from one another such that at least a portion of the isolation trench is formed in the etched recess; filling at least a portion of the isolation trench with an insulation material; forming an insulation layer covering a side surface of the plural light emitting elements; and forming a wiring electrically connecting adjacent light emitting elements, wherein a portion of the insulation layer covers the upper surface of the insulation material. 
         [0015]    In some implementations, the insulation material has an upper surface which is flush with or disposed below the bottom surface of the etched recess. In some implementations, a sidewall of the etched recess has a gentler slope than a sidewall of the isolation trench. In some implementations, the forming of the isolation trench can include removing the first conductivity-type semiconductor layer by etching or laser machining. In some implementations, the forming of the isolation trench can further include performing sulfuric-phosphoric acid treatment after the first conductivity-type semiconductor layer is removed by etching or laser machining. In some implementations, the insulation material includes a polyimide or nano-scale silica. 
         [0016]    In a light emitting diode according to some implementations of the disclosed technology, light emitting elements having a wiring formed thereon can be formed to have a reduced step height by filling an isolation trench with an insulation material. Thus, disconnection of the wiring can be prevented and an entrance of the isolation trench has a reduced width by forming the isolation trench having a sharply inclined sidewall. With this structure, the light emitting diode can prevent reduction in light emitting area due to formation of the isolation trench. Further, the light emitting diode has improved light extraction efficiency using the insulation material filling the isolation trench. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0017]      FIG. 1  is a sectional view of a typical light emitting diode. 
           [0018]      FIG. 2  is a sectional view of an exemplary light emitting diode according to one embodiment of the disclosed technology. 
           [0019]      FIG. 3  is a sectional view of an exemplary light emitting diode according to another embodiment of the disclosed technology. 
           [0020]      FIGS. 4 to 11  are sectional views of light emitting diodes according to various embodiments of the disclosed technology. 
           [0021]      FIGS. 12 to 16  are sectional views for explaining a method for manufacturing a light emitting diode according to embodiments of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    While LED is used in various areas, several problems of the LED such as reduction in life span, reduction in efficiency, deterioration in reliability, etc., have been observed. To solve these problems, an LED which can be driven without a typical converter is being developed. Such an LED generally includes a plurality of light emitting elements on a substrate, and various circuits can be configured by electrically connecting the light emitting elements via interconnection lines. 
         [0023]      FIG. 1  is a schematic sectional view of a typical light emitting diode having a plurality of light emitting elements. 
         [0024]    Referring to  FIG. 1 , the light emitting diode includes a substrate  21 , a plurality of light emitting elements  30 , a transparent electrode  29 , an insulation layer  31 , and a wiring  33 , wherein the light emitting elements  30  include an n-type semiconductor layer  23 , an active layer  25 , and a p-type semiconductor layer  27 . 
         [0025]    The plural light emitting elements  30  are electrically isolated from each other by isolation trenches  30   h  on the substrate  21 . In addition, an upper surface of the n-type semiconductor layer  23  is exposed through an etched recess  27   a  formed by removing the p-type semiconductor layer  27  and the active layer  25 . 
         [0026]    The wiring  33  electrically connects the n-type semiconductor layer  23  of one (first) light emitting element  30  to the p-type semiconductor layer  27  of another (second) light emitting element  30 . The wiring  33  can connect the exposed upper surface of the n-type semiconductor layer  23  to the transparent electrode  29 , as shown in  FIG. 1 . The insulation layer  31  is disposed between the wiring  33  and the light emitting elements  30  and insulates the wiring  33  from a side surface of the light emitting elements  30 . 
         [0027]    Typically, the light emitting diode includes the plural light emitting elements  30 , which are connected in series by the wiring  33 , and can be driven by high-voltage alternating-current power. 
         [0028]    In the typical light emitting diode, the isolation trench  30   h  reaching an upper surface of the substrate  21  is formed in order to ensure electrical isolation between the light emitting elements  30 . A portion of the wiring  33  is formed on the side surface of the light emitting elements  30  in the isolation trench  30   h.  The light emitting elements  30  generally have a height of about 5 μm or more, and thus, when the side surface of the light emitting elements  30  is sharply inclined, it is difficult to form the wiring  33  on the side surface of the light emitting elements  30 , and the wiring  33  is likely to suffer from disconnection. To prevent disconnection of the wiring  33 , the side surface of the light emitting elements  30  is generally formed to have a gentle slope. 
         [0029]    However, when the side surface of the light emitting elements  30  has a gentle slope, an entrance of the isolation trench  30   h  generally has a relatively wide width of about 30 μm for electrical isolation between the light emitting elements  30 , thereby reducing a light emitting area. 
         [0030]    Hereinafter, various implementations of the disclosed technology will be described in detail with reference to the accompanying drawings. It should be understood that the disclosed technology is not limited to the following embodiments and can be embodied in different ways. In the drawings, the widths, lengths, thicknesses and the like of components can be exaggerated for convenience. Like components will be denoted by like reference numerals throughout the specification. 
         [0031]      FIG. 2  is a sectional view of a light emitting diode according to one embodiment of the disclosed technology. 
         [0032]    Referring to  FIG. 2 , the light emitting diode includes a substrate  51 , a plurality of light emitting elements  60 , an isolation trench  60   h,  an insulation material  60   i,  a transparent electrode  59 , an insulation layer  61 , and a wiring  63 . The light emitting elements  60  include a first conductivity-type semiconductor layer  53 , an active layer  55 , and a second conductivity-type semiconductor layer  57 . 
         [0033]    The substrate  51  can be or include a growth substrate on which a gallium nitride-based semiconductor layer can be grown, for example, a sapphire substrate, a SiC substrate, a spinel substrate, or the like. The first conductivity-type semiconductor layer  53 , the active layer  55  and the second conductivity-type semiconductor layer  57  can be grown on the substrate  51  by a growth technique such as MOCVD. Here, the first conductivity-type semiconductor layer  53  is relatively thicker than the second conductivity-type semiconductor layer  57 . For example, the first conductivity-type semiconductor layer  53  has a thickness of about 3 μm or more, and the second conductivity-type semiconductor layer  57  has a thickness of less than about 1 μm. In some implementations, the first conductivity-type semiconductor layer  53  is an n-type semiconductor layer and the second conductivity-type semiconductor layer  57  is a p-type semiconductor layer. 
         [0034]    The plural light emitting elements  60  are formed by patterning the first conductivity-type semiconductor layer  53 , the active layer  55 , and the second conductivity-type semiconductor layer  57 . The light emitting elements  60  are electrically isolated from each other by the isolation trench  60   h,  and the first conductivity-type semiconductor layer  53  of each of the light emitting elements  60  has an upper surface exposed by the etched recess  57   a.  In some implementations, the etched recess  57   a  can be continuously formed around the light emitting elements  60 . In some implementations, the etched recess  57   a  can be formed in some areas on which the wiring  63  is formed. The isolation trench  60   h  is formed around the light emitting elements  60 , and at least a portion of the isolation trench  60   h  is formed in the etched recess  57   a.  As shown in  FIG. 2 , the etched recess  57   a  has a sidewall formed to have a gentler slope than a sidewall of the isolation trench  60   h.  The sidewall of the isolation trench  60   h  can have a relatively steep slope and an entrance of the isolation trench  60   h  can have a width of less than 5 μm. Here, the isolation trench  60   h  is formed using dry or wet etching. 
         [0035]    The transparent electrode  59  is disposed on the second conductivity-type semiconductor layer  57  of each of the light emitting elements  60  and forms ohmic contact with the second conductivity-type semiconductor layer  57 . The transparent electrode  59  can be formed to include a transparent oxide such as ITO or a transparent metal layer such as Ni/Au. 
         [0036]    The insulation material  60   i  fills the isolation trench  60   h  or is included in the isolation trench  60   h.  The insulation material  60   i  can include a polyimide. The polyimide exhibits small thermal shrinkage due to excellent heat resistance thereof, and exhibits outstanding impact resistance, dimensional stability and insulation properties. In addition, the polyimide has a lower index of refraction (about 1.7) than that of gallium nitride (about 2.45) and thus is suitable for total reflection of light travelling in the first conductivity-type semiconductor layer  53 . 
         [0037]    The insulation material  60   i  is disposed in the isolation trench  60   h  and can have an upper surface which is flush with or disposed below the exposed upper surface of the first conductivity-type semiconductor layer  53 . 
         [0038]    The insulation layer  61  covers side surfaces of the light emitting elements  60 , and has an opening exposing the upper surface of the first conductivity-type semiconductor layer  53  and an upper surface of the transparent electrode  59 . The insulation layer  61  can be formed of or include silicon oxide or silicon nitride, and a portion of the insulation layer  61  can cover the upper surface of the insulation material  60   i.    
         [0039]    The wiring  63  electrically connects the first conductivity-type semiconductor layer  53  of one (first) light emitting element to the second conductivity-type semiconductor layer  57  of another (second) light emitting element. As shown in  FIG. 2 , the wiring  63  can connect the exposed upper surface of the first conductivity-type semiconductor layer  53  to the transparent electrode  59 . 
         [0040]    The wiring  63  is disposed on an upper side of the insulation material  60   i  and is insulated from the side surface of the second light emitting element  60  by the insulation layer  61 . In addition, the side surface of the light emitting element  60 , which is covered with the wiring  63 , has a relatively gentle slope. Further, a portion of the side surface of the light emitting element  60 , on which the wiring  63  is formed, has a smaller height than a total height of the light emitting element  60  or a height of the isolation trench  60   h.  Thus, since the wiring  63  can have a shorter length than a wiring of typical light emitting diodes, light absorption by the wiring  63  can be reduced, and the wiring  63  can be more easily formed and be prevented from suffering from disconnection. 
         [0041]    According to this embodiment, since there is no need to form the wiring  63  in the isolation trench  60   h,  the isolation trench  60   h  can have a smaller width. Thus, reduction in light emitting area due to formation of the isolation trench  60   h  can be mitigated. 
         [0042]      FIG. 3  is a sectional view of a light emitting diode according to another embodiment of the disclosed technology. 
         [0043]    Referring to  FIG. 3 , the light emitting diode according to this embodiment is generally similar to the light emitting diode of  FIG. 2  except that an isolation trench  70   h  is formed by laser machining. 
         [0044]    The isolation trench  70   h  is formed by laser irradiation and thus can be extended to the interior of the substrate  51 . Since the isolation trench  70   h  is formed by laser irradiation, the isolation trench  70   h  can have a smaller width with decreasing distance between the isolation trench  70   h  and the substrate  51 . When the isolation trench  70   h  is formed by laser irradiation, phosphoric acid treatment (at 90° C. to 120° C. and for 5 minutes to 12 minutes) is performed to remove defects of a gallium nitride layer due to laser irradiation. 
         [0045]    According to this embodiment, the isolation trench  70   h  is formed by laser machining and thus can have a further reduced width. 
         [0046]      FIG. 4  is a sectional view of a light emitting diode according to a further embodiment of the disclosed technology. 
         [0047]    Referring to  FIG. 4 , the light emitting diode according to this embodiment is generally similar to the light emitting diode of  FIG. 2  except that an insulation material  70   i  is formed of or includes nanoparticles. 
         [0048]    That is, according to this embodiment, the insulation material  70   i  includes nanoparticles, and the nanoparticles can be or include, for example, nano-scale spherical silica. Nanoparticles having a relatively low index of refraction, for example, an index of refraction of about 1.46, is used, thereby improving light extraction efficiency through reflection of light travelling in the first conductivity-type semiconductor layer  53  by the nanoparticles. Further, since air having an index of refraction of 1 remains between the nanoparticles, light can be reflected better. 
         [0049]      FIG. 5  is a sectional view of a light emitting diode according to yet another embodiment of the disclosed technology. 
         [0050]    Referring to  FIG. 5 , the light emitting diode according to this embodiment is generally similar to the light emitting diode of  FIG. 3  except that the insulation material  70   i  is formed of or includes nanoparticles, as described with reference to  FIG. 4 . 
         [0051]      FIG. 6  is a sectional view of a light emitting diode according to yet another embodiment of the disclosed technology. 
         [0052]    Referring to  FIG. 6 , the light emitting diode according to this embodiment is generally similar to the light emitting diode of  FIG. 3  except that an air gap  70   v  remains between the insulation material  60   i  and the substrate  51 . That is, the insulation material  60   i  does not completely fill the isolation trench  70   h  and the air gap  70   v  is formed in a lower portion of the isolation trench  70   h.    
         [0053]    Since the air gap  70   v  has a reflectivity of 1 and thus is more advantageous for total internal reflection than the polyimide  60   i,  the light emitting diode can have further improved light extraction efficiency. 
         [0054]      FIG. 7  is a sectional view of a light emitting diode according to yet another embodiment of the disclosed technology. 
         [0055]    Referring to  FIG. 7 , the light emitting diode according to this embodiment is generally similar to the light emitting diode of  FIG. 6  except that nanoparticles  70   i  instead of the air gap  70   v  are disposed. 
         [0056]    The nanoparticles  70   i  are disposed in a lower portion of the isolation trench  70   h,  and the polyimide  60   i  can be disposed on the nanoparticles  70   i.    
         [0057]      FIG. 8  is a sectional view of a light emitting diode according to yet another embodiment of the disclosed technology. 
         [0058]    Referring to  FIG. 8 , the light emitting diode according to this embodiment is generally similar to the light emitting diode of  FIG. 2  except that an isolation trench  80   h  has a reversely inclined sidewall. 
         [0059]    Since light travelling in the first conductivity-type semiconductor layer  53  can be easily emitted to outside by adjusting a slope of the sidewall, the light emitting diode can have further improved light extraction efficiency. 
         [0060]    The isolation trench  80   h  can be formed by forming the isolation trench  60   h  in  FIG. 2 , followed by sulfuric-phosphoric acid treatment (H 2 SO 4 :H 3 PO 4 =3:1, 280° C., about 5 minutes). 
         [0061]      FIG. 9  is a sectional view of a light emitting diode according to yet another embodiment of the disclosed technology. 
         [0062]    Referring to  FIG. 9 , the light emitting diode according to this embodiment is generally similar to the light emitting diode of  FIG. 3  except that an isolation trench  90   h  has a reversely inclined sidewall. 
         [0063]    The isolation trench  90   h  can be formed by forming the isolation trench  70   h  in  FIG. 3 , followed by sulfuric-phosphoric acid treatment (H 2 SO 4 :H 3 PO 4 =3:1, 280° C., about 5 minutes). Thus, the isolation trench  70   h  that is extended to an interior of the substrate  51  remains. 
         [0064]      FIG. 10  is a sectional view of a light emitting diode according to yet another embodiment of the disclosed technology. 
         [0065]    Referring to  FIG. 10 , the light emitting diode according to this embodiment is generally similar to the light emitting diode of  FIG. 8  except that an insulation material  70   i  is formed of or includes nanoparticles, as described with reference to  FIG. 4 . 
         [0066]      FIG. 11  is a sectional view of a light emitting diode according to yet another embodiment of the disclosed technology. 
         [0067]    Referring to  FIG. 11 , the light emitting diode according to this embodiment is generally similar to the light emitting diode of  FIG. 10  except that nanoparticles  70   i  are disposed in a lower portion of the isolation trench  90   h  and a polyimide  60   i  is disposed in an upper portion of the isolation trench  90   h.    
         [0068]      FIGS. 12 and 13  are sectional views for explaining a method for manufacturing a light emitting diode according to one embodiment of the disclosed technology. 
         [0069]    Referring to  FIG. 12 , a first conductivity-type semiconductor layer  53 , an active layer  55  and a second conductivity-type semiconductor layer  57  are grown on a substrate  51 . The semiconductor layers are formed of or includes a gallium nitride-based semiconductor and can be grown using a growth technique such as MOCVD or MBE and the like. Although not shown in  FIG. 12 , a buffer layer can be grown before growth of the first conductivity-type semiconductor layer  53 . 
         [0070]    Next, an etched recess  57   a  exposing the first conductivity-type semiconductor layer  53  is formed by etching the second conductivity-type semiconductor layer  57  and the active layer  55 . The first conductivity-type semiconductor layer  53  has an upper surface exposed by the etched recess  57   a.  The etched recess  57   a  has a sidewall having a relatively gentle slope, as shown in  FIG. 12 . 
         [0071]    Referring to  FIG. 13 , an isolation trench  60   h  electrically isolating a plurality of light emitting elements  60  from one another is formed. Before the isolation trench  60   h  is formed, a mask pattern  58  covering other regions excluding the isolation trench  60   h  can be formed. The mask pattern  58  can be formed of or include silicon oxide or silicon nitride. 
         [0072]    Next, the isolation trench  60   h  can be formed by dry or wet etching of the region exposed by the mask pattern  58 . 
         [0073]    The mask pattern  58  can be removed after formation of the isolation trench  60   h . Next, an insulation material  60   i  (see  FIG. 2 ) can be formed to fill the isolation trench  60   h , followed by formation of a transparent electrode  59 , an insulation layer  61  and a wiring  63 , thereby manufacturing the light emitting diode as shown in in  FIG. 2 . The insulation material  60   i  can be formed by spin coating of a photosensitive polyimide, followed by exposure to light and development to remove the polyimide in the remaining regions excluding the polyimide in the isolation trench  60   h.    
         [0074]    The transparent electrode  59  can be formed before formation of the isolation trench  60   h,  the mask pattern  58  or the insulation material  60   i.    
         [0075]    The light emitting diode as shown in  FIG. 4  can be manufactured by filling the isolation trench  60   h  with nanoparticles, for example, an insulation material  70   i  (see  FIG. 4 ), instead of the insulation material  60   i.  The insulation material  70   i  can be formed by dispersing the nanoparticles in water or another solvent, followed by spin coating. 
         [0076]      FIG. 14  is a sectional view of a method for manufacturing a light emitting diode according to another embodiment of the disclosed technology. 
         [0077]    Referring to  FIG. 14 , before removal of the mask pattern  58  and after formation of the isolation trench  60   h  as described above with reference to  FIGS. 12 and 13 , sulfuric-phosphoric acid treatment (H 2 SO 4 :H 3 PO 4 =3:1, 280° C., about 5 minutes) can be performed, thereby forming an isolation trench  80   h  having a reversely inclined sidewall. 
         [0078]    Next, the mask pattern  58  can be removed, followed by formation of an insulation material  60   i  (see  FIG. 8 ), a transparent electrode  59 , an insulation layer  61  and a wiring  63 , thereby manufacturing the light emitting diode as shown in  FIG. 8 . 
         [0079]      FIG. 15  is a sectional view of a method for manufacturing a light emitting diode according to a further embodiment of the disclosed technology. 
         [0080]    Referring to  FIG. 15 , the method for manufacturing a light emitting diode according to this embodiment is generally similar to the method for manufacturing a light emitting diode described with reference to  FIGS. 12 and 13  except that an isolation trench  70   h  is formed by laser machining. 
         [0081]    The isolation trench  70   h  isolating the light emitting elements  60  from one another can be formed by laser irradiation and phosphoric acid treatment can be performed to remove gallium nitride damaged by laser irradiation. The isolation trench  70   h  can be formed to be extended to the interior of the substrate  51  by laser machining. 
         [0082]    According to this embodiment, a mask pattern  58  can be formed before laser irradiation so as to define an entrance of the isolation trench  70   h.  However, other implementations are also possible without being limited thereto. For example, since a mask material can be removed by laser irradiation, the semiconductor layers in which the isolation trench  70   h  is formed are covered with a mask material layer, followed by direct laser irradiation, thereby forming the isolation trench  70   h.    
         [0083]    The light emitting diode as shown in  FIG. 3  may be manufactured in the following manners. After the isolation trench  70   h  is formed, the mask pattern  58  is removed, an insulation material  60   i  (see  FIG. 3 ) for filling the isolation trench  70   h  is formed, and a transparent electrode  59 , an insulation layer  61  and a wiring  63  are formed. The insulation material  60   i  can be formed such that an air gap  70   v  (see  FIG. 6 ) remains, thereby manufacturing the light emitting diode as shown in  FIG. 6 . In addition, nanoparticles  70   i  (see  FIG. 5 ) can fill the isolation trench  70   h  instead of the insulation material  60   i,  thereby manufacturing the light emitting diode as shown in  FIG. 5 . Further, the nanoparticles and the polyimide can also be combined, thereby manufacturing the light emitting diode as shown in  FIG. 7 . 
         [0084]      FIG. 16  is a sectional view for explaining a method for manufacturing a light emitting diode according to yet another embodiment of the disclosed technology. 
         [0085]    Referring to  FIG. 16 , the method for manufacturing a light emitting diode according to this embodiment further includes forming an isolation trench  90   h  having a reversely inclined sidewall by sulfuric-phosphoric acid treatment (H 2 SO 4 :H 3 PO 4 =3:1, 280° C., about 5 minutes) before removal of the mask pattern  58  and after formation of the isolation trench  70   h  as described above in  FIG. 15 . 
         [0086]    Next, the mask pattern  58  is removed, followed by filling the isolation trench  90   h  with the insulation material  60   i,  the insulation material  70   i,  or a combination thereof, thereby manufacturing the light emitting diode as shown in  FIG. 9 ,  10  or  11 .