Abstract:
Disclosed are a light emitting device, a conductive substrate; a second electrode layer on the conductive substrate and including a center portion and a peripheral portion surrounding the center portion; a protective layer on the peripheral portion of the second electrode layer; and a light emitting structure including a second conductive semiconductor layer on the second electrode layer, an active layer on the second conductive semiconductor layer and a first conductive semiconductor layer on the active layer; and a first electrode layer on the first conductive semiconductor layer, wherein the second conductive semiconductor layer includes edge portions extending outside of the light emitting structure.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of co-pending U.S. patent application Ser. No. 12/921,534 filed on Sep. 8, 2010, which is the national phase of PCT International Application No. PCT/KR2009/004025 filed on Jul. 21, 2009, which claims priority to Application No. 10-2008-0070431 filed in the Republic of Korea on Jul. 21, 2008, the entire contents of all of the above applications are hereby incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The embodiment relates to a light emitting diode, a method of manufacturing the same, a light emitting device and a method of manufacturing the same. 
     Discussion of the Related Art 
     Recently, a light emitting diode is extensively used as a light emitting device. 
     The light emitting diode includes an n type semiconductor layer, an active layer and a p type semiconductor layer. As power is applied to the n type semiconductor layer and the p type semiconductor layer, respectively, the active layer emits light. The light emitting diode can be manufactured to emit light having various colors suitable for various application fields. 
     The light emitting device employing the light emitting diode includes a phosphor, which is excited by light emitted from the light emitting diode so that excite light can be emitted, thereby emitting light having various colors. 
     For instance, a first molding member including a yellow phosphor can be formed to surround the light emitting diode that emits light having a wavelength of blue color. The yellow phosphor is excited by light emitted from the light emitting diode, thereby emitting excite light having a wavelength of yellow color. 
     SUMMARY OF THE INVENTION 
     The embodiment provides a light emitting diode, a method of manufacturing the same, a light emitting device and a method of manufacturing the same. 
     The embodiment provides a light emitting diode having improved insulation properties and a method of manufacturing the same. 
     The embodiment provides a light emitting device including a light emitting diode and a method of manufacturing the same capable of easily processing a molding member used for the light emitting device. 
     The embodiment provides a method of manufacturing a light emitting device, capable of simultaneously processing molding members for a plurality of light emitting devices. 
     A light emitting device according to an embodiment includes a circuit board formed with a first conductive pattern and a second conductive pattern electrically isolated from the first conductive pattern; a light emitting diode electrically connected to the first and second conductive patterns on the circuit board; a first molding member surrounding the light emitting diode; and a second molding member on the first molding member, wherein the light emitting diode includes a conductive support substrate, a reflective electrode layer having a convex center portion on the conductive support substrate, a protective layer on a peripheral portion of the reflective electrode layer, a second conductive semiconductor layer on the reflective layer and the protective layer, an active layer on the second conductive semiconductor layer, a first conductive semiconductor layer on the active layer, and a first electrode layer on the first conductive semiconductor layer. 
     A method of manufacturing a light emitting device according to an embodiment includes forming a light emitting diode on a circuit board; forming a first molding member on the circuit board such that the first molding member surrounds the light emitting diode; forming a second molding member on the first molding member and performing a preliminary curing process; and providing a pressing member to deform a shape of the second molding member and performing a main curing process. 
     A light emitting diode according to an embodiment includes a conductive support substrate; a reflective electrode layer having a convex center portion on the conductive support substrate; a protective layer on a peripheral portion of the reflective electrode layer; a second conductive semiconductor layer on the reflective layer and the protective layer; an active layer on the second conductive semiconductor layer; a first conductive semiconductor layer on the active layer; and a first electrode layer on the first conductive semiconductor layer. 
     The embodiment can provide a light emitting diode, a method of manufacturing the same, a light emitting device and a method of manufacturing the same. 
     The embodiment can provide a light emitting diode having improved insulating properties and a method of manufacturing the same. 
     The embodiment can provide a light emitting device including a light emitting diode having improved insulating properties and a method of manufacturing the same capable of easily processing a molding member used for the light emitting device. 
     The embodiment can provide a method of manufacturing a light emitting device, capable of simultaneously processing molding members for a plurality of light emitting devices. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a sectional view showing a light emitting diode according to an embodiment; 
         FIGS. 2 to 9  are views showing a method of manufacturing a light emitting diode according to an embodiment; 
         FIG. 10  is a view showing a light emitting device including a light emitting diode according to an embodiment; 
         FIG. 11  is a view showing a light distribution characteristic of a light emitting device according to an embodiment; and 
         FIGS. 12 to 19  are views showing a method of manufacturing a light emitting device according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the description of the embodiments, it will be understood that, when a layer (or film), a region, a pattern, or a structure is referred to as being “on” or “under” another substrate, another layer (or film), another region, another pad, or another pattern, it can be “directly” or “indirectly” on the other substrate, layer (or film), region, pad, or pattern, or one or more intervening layers may also be present. Such a position of the layer has been described with reference to the drawings. 
     The thickness and size of each layer shown in the drawings can be exaggerated, omitted or schematically drawn for the purpose of convenience or clarity. In addition, the size of elements does not utterly reflect an actual size. 
     Hereinafter, a light emitting diode, a method of manufacturing the same, a light emitting device and a method of manufacturing the same according to embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
       FIG. 1  is a sectional view showing a light emitting diode according to an embodiment. 
     Referring to  FIG. 1 , the light emitting diode  100  includes a first conductive semiconductor layer  102 , an active layer  104 , a second conductive semiconductor layer  106 , a protective layer  107 , a reflective electrode layer  108 , and a conductive support substrate  110 . In addition, a first electrode layer  112  is formed on the first conductive semiconductor layer  102 . 
     The first conductive semiconductor layer  102  may include an n type semiconductor layer. The n type semiconductor layer may include a GaN based compound semiconductor layer, such as a GaN layer, an AlGaN layer or an InGaN layer. 
     The active layer  104  is formed under the first conductive semiconductor layer  102 . The active layer  104  may have a single quantum well structure or a multiple quantum well structure. For instance, the active layer  104  may have a single quantum well structure or a multiple quantum well structure including InGaN well/GaN barrier layers. In the In x Ga 1-x N well layer, x is in the range of 0≦x≦1. 
     The second conductive semiconductor layer  106  is formed under the active layer  104 . The second conductive semiconductor layer  106  may include a p type semiconductor layer. The p type semiconductor layer may include a GaN based compound semiconductor layer, such as a GaN layer, an AlGaN layer or an InGaN layer into which p type impurities, such as Mg, are implanted. 
     In addition, a third conductive semiconductor layer (not shown) can be formed under the second conductive semiconductor layer  106 . The third conductive semiconductor layer may include an n type semiconductor layer. 
     According to another embodiment, the first conductive semiconductor layer  102  may include the p type semiconductor layer and the second conductive semiconductor layer  106  may include the n type semiconductor layer. 
     The protective layer  107  and the reflective electrode layer  108  are formed under the second conductive semiconductor layer  106 . 
     The reflective electrode layer  108  makes contact with the center of a bottom surface of the second conductive semiconductor layer  106 , and the protective layer  107  makes contact with the peripheral portion of the bottom surface of the second conductive semiconductor layer  106 . 
     The protective layer  107  makes contact with a top surface and side surfaces of the reflective electrode layer  108 . 
     The protective layer  107  may increase a longitudinal interval between a lateral side of the reflective electrode layer  108  or the conductive support substrate  110  and the first electrode layer  112  or the first conductive semiconductor layer  102 . 
     Thus, the reflective electrode layer  108  or the conductive support substrate  110  can be prevented from being electrically shorted from the first electrode layer  112  or the first conductive semiconductor layer  102  by foreign substance. 
     The protective layer  107  having a predetermined height h 1  and a predetermined width w 1  is formed under a peripheral portion of the second conductive semiconductor layer  106 . The protective layer  107  may include a semiconductor layer which is equal to or different from the second conductive semiconductor layer  106 . In addition, the protective layer  107  may include an insulating layer. 
     In detail, the protective layer has the width w 1  of about 20 to 600 μm and the height h 1  of 5 to 500 μm on the basis of the second conductive semiconductor layer  106 . In addition, the protective layer  107  may include one of an n type semiconductor layer, a p type semiconductor layer and an undoped semiconductor layer. The protective layer  107  can be prepared as a stack structure including at least two of the n type semiconductor layer, the p type semiconductor layer and the undoped semiconductor layer. For instance, the protective layer  107  may include at least one of an n type GaN layer, a p type GaN layer, and an undoped GaN layer. The protective layer  107  may include the p type GaN layer identical Cu the second conductive semiconductor layer  106 . 
     An etching groove  105 , which is formed by mesa-etching predetermined portions of the first conductive semiconductor layer  102  and the second conductive semiconductor layer  106  such that the protective layer  107  can be partially exposed through the etching groove  105 , may increase the horizontal interval between a lateral side of the reflective electrode layer  108  or the conductive support layer  110  and the first electrode layer  112  or the first conductive semiconductor layer  102 . 
     Therefore, the reflective electrode layer  108  or the conductive support substrate  110  can be prevented from being electrically shorted from the first electrode layer  112  or the first conductive semiconductor layer  102  by foreign substance. 
     The etching groove  105  may have a width w 2  of about 10 to 500 μm. The width w 2  of the etching groove  105  is smaller than the width w 1  of the protective layer  107  (w 1 &gt;w 2 ). 
     If the width w 2  of the etching groove  105  is equal to or greater than the width w 1  of the protective layer  107 , the reflective electrode layer  108  may be exposed upward due to the mesa etching. 
     The conductive support substrate  110  is formed under the reflective electrode layer  108 . 
     The reflective electrode layer  108  may serve as a p type electrode having an ohmic contact function so stably supply external current. The p type electrode may include at least one of Ag, Ni, Al, Rh, Pd, Er, Ru, Mg, Zn, Pt, Au and Hf. The conductive support substrate  110  may include Cu or Au. 
     In the light emitting diode according to the embodiment, the reflective electrode layer  108  and the conductive support substrate  110  may serve as a second electrode layer for supplying power to the second conductive semiconductor layer  106  in correspondence with the first electrode layer  112  for supplying power to the first conductive semiconductor layer  102 . 
     A center portion of the top surface of the second electrode layer protrudes upward relative to a peripheral potion of the top surface of the second electrode layer. According to the embodiment, the center portion of the reflective electrode layer  108  protrudes upward relative to the peripheral portion of the reflective electrode layer  108 . 
     Since the center portion of the top surface of the second electrode layer protrudes upward relative to the peripheral portion of the top surface of the second electrode layer, the electric insulation property of the light emitting diode can be improved. The protective layer  107  may be selectively formed. 
       FIGS. 2 to 9  are views showing a method of manufacturing the light emitting diode according to the embodiment. 
     Referring to  FIGS. 2 and 3 , the first conductive semiconductor layer  102  is formed on the substrate  101 , the active layer  104  is formed on the first conductive semiconductor layer  102 , and the second conductive semiconductor layer  106  is formed on the active layer  104 . The first conductive semiconductor layer  102  may include the n type semiconductor layer, and the second conductive semiconductor layer  106  may include the p type semiconductor layer, or vice versa. 
     Referring to  FIG. 4 , an oxide layer pattern (for instance SiO 2 ) (not shown) is formed on a center portion  106 A of the second conductive semiconductor layer  106  and then the protective layer  107  having a predetermined height h 1  and a predetermined width w 1  is formed on a peripheral portion  106 B of the second conductive semiconductor layer  106  by using the oxide layer pattern as a mask. 
     The protective layer  107  may include one of an n type GaN layer, a p type GaN layer and an undoped GaN layer. The protective layer  107  can be prepared as a stack structure including at least two of the n type GaN layer, the p type GaN layer and the undoped GaN layer. The protective layer  107  may include an insulating layer. For instance, the undoped GaN layer can be formed by supplying NH 3  and TMGa gas at the growth temperature of about 900° C. 
     The protective layer  107  may have a width w 1  of about 20 to 600 μm and a height h 1  of about 5 to 500 μm. 
     After the protective layer  107  has been formed, the oxide layer pattern is removed from the center portion of the second conductive semiconductor layer  106 . 
     Referring to  FIG. 5 , the reflective electrode layer  108  is formed on the second conductive semiconductor layer  106  and the protective layer  107 , and the conductive support substrate  110  is formed on the reflective electrode layer  108 . 
     Referring to  FIGS. 6 and 7 , the substrate  101  formed under the first conductive semiconductor layer  102  is removed through a laser lift off (LLO) process. That is, laser having a predetermined wavelength band is irradiated onto the substrate  101 , so that thermal energy is concentrated onto a boundary surface between the substrate  101  and the first conductive semiconductor layer  102 , thereby separating the substrate  101  from the first conductive semiconductor layer  102 . 
     After the substrate  101  has been removed, the surface of the first conductive semiconductor layer  102  is polished through an inductively coupled plasma/reactive ion etching (ICP/RIE) process. 
     Referring to  FIG. 8 , the resultant structure, in which the substrate  101  is removed, is turned over such that the conductive support substrate  110  can be placed below the light emitting structure. 
     In addition, the mesa etching is performed from the first conductive semiconductor layer  102  to the second conductive semiconductor layer  106 , thereby forming the etching groove  105 . The mesa etching may include dry etching or wet etching. The mesa etching may be continued until the second conductive semiconductor layer  106  or the protective layer  107  is partially exposed. Thus, the etching groove  105  ranging from the first conductive semiconductor layer  102  to the second conductive semiconductor layer  106  can be formed. 
     The etching groove  105  has a width w 2  of about 10 to 500 μm, which is smaller than a width w 1  of the protective layer  107  (see,  FIG. 4 ). 
     Referring to  FIG. 9 , the first electrode layer  112  is formed on the first conductive semiconductor layer  102 . The first electrode layer  112  may include a transparent electrode layer or a transparent layer can be formed between the first electrode layer  112  and the first conductive semiconductor layer  102 . 
     The light emitting diode  100  according to the embodiment includes the protective layer  107  and the etching groove  105 , so that the light emitting diode  100  can be prevented from being electrically shorted due to foreign substance. 
     Thus, insulation properties of the light emitting diode  100  can be improved. 
       FIG. 10  is a view showing a light emitting device including a light emitting diode according to the embodiment. 
     Referring to  FIG. 10 , the light emitting device according to the embodiment includes a circuit board  10  having a first conductive pattern (not shown) and a second conductive pattern (not shown) spaced apart from the first conductive pattern, a light emitting diode  100  electrically connected to the circuit board  10  through a wire  21 , a guide ring  11  disposed around the light emitting diode  100  on the circuit board  10 , a first molding member  30  supported by the guide ring  11  and including a phosphor  31 , and a second molding member  40  formed on the first molding member  30 . 
     As shown in  FIGS. 9 and 10 , the conductive support substrate  110  of the light emitting diode  100  is electrically connected to the first conductive pattern formed on the circuit board  10 , and the first electrode layer  112  of the light emitting diode  100  is electrically connected to the second conductive pattern, which is electrically isolated from the first conductive pattern, through the wire  21 . 
     The first molding member  30  surrounds the light emitting diode  100  in such a manner that the phosphor  31  of the first molding member  30  can be excited by light emitted from the light emitting diode  100 . The phosphor  31  is distributed in the first molding member  30 . According to another embodiment, the first molding member  30  can be omitted. In this case, the second molding member  40  may include the region for the first molding member  30 . 
     The second molding member  40  is formed on the first molding member  30  to decide the distribution characteristic of light emitted from the light emitting diode  100 . 
     According to the light emitting device of the embodiment, the second molding member  40  has a convex top surface and the center of the convex top surface subsides. 
       FIG. 11  is a view showing the light distribution characteristic of the light emitting device according to the embodiment. 
     As shown in  FIG. 11 , the light distribution characteristic of the light emitting device may vary depending on the configuration of the second molding member  40  serving as a lens. According to the embodiment, the second molding member  40  has a convex configuration as a whole and the center of the second molding member  40  subsides in such a manner that the light emitting device may emit the light at an angle of 45°. 
     Such a light emitting device can be suitably used as a backlight unit for a display device. 
       FIGS. 12 to 19  are views showing a method of manufacturing a light emitting device according to an embodiment. 
     Referring to  FIG. 12 , the guide ring  11  and the light emitting diode  100  are installed on the circuit board  10 . At this time, the light emitting diode  100  is disposed such that the conductive support substrate  110  of the light emitting diode  100  can make contact with the first conductive pattern of the circuit board  10 . In addition, the first electrode layer  112  of the light emitting diode is electrically connected to the second conductive pattern of the circuit board  10  through the wire  21 . 
     Referring to  FIG. 13 , the first molding member  30  including the phosphor  31  is formed on the circuit board  10  having the light emitting diode  100  in such a manner that the first molding member  30  may surround the light emitting diode  100 . The first molding member  30  is supported by the guide ring  11  and has a thickness sufficient for covering the light emitting diode  100 . 
     Referring to  FIG. 14 , the second molding member  40  including resin material, such as silicone, is formed on the first molding member  30 . The second molding member  40  decides the distribution characteristic of light emitted from the light emitting diode  100 . Primarily, the second molding member  40  is formed in a convex configuration and is subject to a preliminary curing process. 
     For instance, the preliminary curing process can be performed for 5 to 15 minutes at the temperature of 40 to 80° C. 
     Referring to  FIG. 15 , after the preliminary curing process has been performed, the second molding member  40  is pressed by a pressing member  50 .  FIG. 16  shows a pressing member  50  according to another embodiment. 
     As shown in  FIGS. 15 and 16 , the main curing process is performed in a state in which the second molding member  40  is pressed by the pressing member  50 . 
     For instance, the main curing process can be performed for 5 to 15 minutes at the temperature of 130 to 170° C. 
     The light emitting device as shown in  FIG. 10  can be obtained after the preliminary and main curing processes have been completed. 
     Meanwhile, according to the method of manufacturing the light emitting device of the embodiment, the second molding members  40  of plural light emitting devices formed on the circuit board  10  can be simultaneously processed, so that productivity can be improved. 
     Referring to  FIG. 17 , a plurality of light emitting devices  60  formed with second molding members  40  as shown in  FIG. 14  are provided on the circuit board  10  having conductive patterns (not shown) and terminals  12  for supplying power to the conductive patterns. 
     Guide pin insertion holes  70  can be formed in the circuit board  10 . 
     Meanwhile, a molding board  80  shown in  FIG. 18  has a size identical to that of the circuit board  10 . Guide pins  81  are provided on the molding board  80 . The guide pins  81  are inserted into the guide pin insertion holes  70  to precisely align the circuit board  10  and the molding board  80 . Spacer members  82  are provided on the molding board  80  such that the circuit board  10  can be spaced apart from the molding board  80  by a predetermined distance. Pressing members  50  are provided on the molding board  80  corresponding to the light emitting devices  60  in order to press the second molding members  40  of the light emitting devices  60 . 
     The molding member  50  shown in  FIG. 18  is identical to the molding member  50  shown in  FIG. 15 . In addition, various types of molding members can be used depending on the shape of the second molding members  40 . 
     As shown in  FIG. 19 , in a state in which the circuit board  10  and the molding board  80  are aligned in opposition to each other, a magazine  90  having a plurality of horizontal slots  91  are fitted with the circuit board  10  and the molding board  80 . 
     At this time, the guide pins  81  are inserted into the guide pin insertion holes  70  of the circuit board  10  so that the circuit board  10  and the molding board  80  can be prevented from being shaken in the horizontal direction. The circuit hoard  10  can be spaced apart from the molding board  10  corresponding to an interval between slots  91  of the magazine  90  by the spacer members  82 . For the purpose of explanation, the position of the guide pins  81  and the spacer members  82  shown in  FIG. 18  is different from the position of the guide pins  81  and the spacer members  82  shown in  FIG. 19 . The number and position of the guide pins  81  and the spacer members  82  may vary depending on applications thereof. 
     As shown in  FIG. 19 , the main curing process is performed with respect to the light emitting devices  60  in a state in which the circuit board  10  is assembled with the molding board  80 . 
     Thus, the second molding members  40  can be simultaneously processed for the light emitting devices  60  formed in the circuit board  10 . 
     Meanwhile, since a plurality of circuit boards  10  and molding boards  80  can be fitted with the magazine  90  corresponding to the number of slots  91  formed in the magazine  90 , the second molding members  40  can be simultaneously processed for the light emitting devices  60  formed in the plural circuit boards  10 . 
     According to the method of manufacturing the light emitting device of the embodiment, the molding member of the light emitting device can be easily processed and the molding members can be simultaneously processed for the plural light emitting devices. 
     Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art. 
     Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other ones of the embodiments. 
     The embodiment is applicable in a light emitting diode, a method of manufacturing the same, a light emitting device and a method of manufacturing the same.