Abstract:
A light emitting device package including a substrate; a light emitting device on the substrate; a first heatsink between the substrate and the light emitting device to transfer heat generated from the light emitting device; a second heatsink disposed below the first heatsink; and an electrode between the first heat sink and the light emitting device. Further, the substrate is disposed between the first and second heatsinks and is narrower at a position between the first and second heatsinks than at a position not between the first and second heatsinks, a material of the substrate is the same at the position between the first and second heatsinks as not between the first and second heatsinks, and the substrate at the position not between the first and second heatsinks surrounds the first and second heat sinks.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a Continuation of prior pending application Ser. No. 12/709,973, filed on Feb. 22, 2010, which claims priority under 35 U.S.C. §119(e) to Korean Patent Application No. 10-2009-0014789, filed on Feb. 23, 2009. The entire contents of the above applications is hereby incorporated by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    Embodiments relate to a light emitting device package and a method of manufacturing the same. 
         [0003]    A light emitting diode (LED) has been widely used as a light emitting device. 
         [0004]    The LED includes a first conductive type semiconductor layer, an active layer, and a second conductive type semiconductor layer, which are sequentially stacked on each other so that light generated from the active layer is emitted to the outside according to a voltage applied thereto. 
         [0005]    A light emitting device package may have a structure in which a light emitting device is disposed on a silicon (Si) substrate. Since the Si substrate has a high thermal resistance, a thermal emission characteristic may be inferior, and also, a light emission characteristic of the light emitting device may be degraded. 
       SUMMARY 
       [0006]    Embodiments provide a light emitting device package having a novel structure and a method of manufacturing the same. 
         [0007]    Embodiments also provide a light emitting device package having an improved thermal emission characteristic and a method of manufacturing the same. 
         [0008]    In one embodiment, a light emitting device package comprises: a substrate; a light emitting device on the substrate; a first heatsink between the substrate and the light emitting device, the first heatsink being at least partially disposed within the substrate to transfer heat generated from the light emitting device; first and second electrodes electrically separated from each other, the first and second electrodes being electrically connected to the light emitting device. 
         [0009]    In another embodiment, a light emitting device package Comprises: a substrate comprising a cavity; a light emitting device within the cavity; a first heatsink between the light emitting device and the substrate; and first and second electrodes electrically separated from each other, the first and second electrodes being electrically connected to the light emitting device. 
         [0010]    In further another embodiment, a light emitting device package comprises: a substrate; a light emitting device on the substrate; a heatsink disposed below the light emitting device with the substrate therebetween, the heatsink being at least partially buried in a lower portion of the substrate; and first and second electrodes electrically separated from each other, the first and second electrodes being electrically connected to the light emitting device. 
         [0011]    The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIGS. 1 to 5  are views of a light emitting device and a method of manufacturing the light emitting device according to an embodiment. 
           [0013]      FIG. 6  is a perspective view of a light emitting device according to an embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0014]    In the following description, it will be understood that when a layer (or film) is referred to as being ‘on’ another layer or substrate, it can be directly on the another layer or substrate, or intervening layers may also be present. Further, it will be understood that when a layer is referred to as being ‘under’ another layer, it can be directly under the another layer, and one or more intervening layers may also be present. Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. In the following description, words “above,” “one,” “below,” and “underneath” are based on the accompanying drawings. 
         [0015]    In the drawings, the thickness or size of each layer is exaggerated, omitted, or schematically illustrated for convenience in description and clarity. Also, the size of each element does not entirely reflect an actual size. 
         [0016]    Hereinafter, a light emitting device package and a method of manufacturing the same according to an embodiment will be described in detail with reference to accompanying drawings. 
         [0017]      FIGS. 1 to 5  are views of a light emitting device and a method of manufacturing the light emitting device according to an embodiment, and  FIG. 6  is a perspective view of a light emitting device according to an embodiment. 
         [0018]    Referring to  FIGS. 5 and 6 , a light emitting device package includes a substrate  10 , an insulating layer  20  disposed on the substrate  10 , a first heatsink  31  disposed on an upper portion of the substrate  10 , a second heatsink  32  disposed on a lower portion of the substrate  10 , first and second electrodes  41  and  42  disposed on the substrate  10  and electrically separated from each other, and a light emitting device  50  electrically connected to the first and second electrodes  41  and  42 . 
         [0019]    The substrate  10  may be formed of a conductive material or an insulating material. The insulating layer  20  electrically insulates the substrate  10 . For example, the substrate  10  may be formed of Si material that is the insulating material. The insulating layer  20  may be disposed on a surface of the substrate  10  to prevent current from leaking. The insulating layer  20  may include a Si oxide layer in which a substrate formed of the Si material is oxidized. 
         [0020]    A first cavity (see reference numeral  11  of  FIG. 1 ) is defined in a top surface of the substrate  10 . A second cavity (see reference numeral  12  of  FIG. 1 ) is defined within the first cavity  11 . The first heatsink  31  is buried within at least a portion of the second cavity  12 . 
         [0021]    A third cavity (see reference numeral  13  of  FIG. 1 ) is defined in a bottom surface of the substrate  10 . The second heatsink  32  is buried within at least a portion of the third cavity  13 . For example, a top surface of the first heatsink  31  may flush with a top surface of the insulating layer  20  disposed on a bottom surface of the first cavity  11 . A bottom surface of the second heatsink  32  may flush with a bottom surface of the insulating layer  20  disposed on a bottom surface of the substrate  10 . 
         [0022]    For example, the first and second heatsinks  31  and  32  may be formed of copper (Cu) or aluminium (Al) having a superior thermal conductivity, but is not limited thereto. 
         [0023]    The first and second heatsinks  31  and  32  are disposed at positions corresponding to each other. That is, the first and second heatsinks  31  and  32  vertically overlap each other. Thus, heat may be effectively transferred from the first heatsink  31  to the second heatsink  32 . Also, only one of the first and second heatsinks  31  and  32  may be provided. 
         [0024]    The substrate  10  may have a thickness of 400 μm to 800 μm. The substrate  10  disposed below the first heatsink  31  may have a thickness of 10 μm to 20 μm. That is, when all of the first and second heatsinks  31  and  32  is provided, the substrate  10  between the first heatsink  31  and the second heatsink  32  may have a thickness of 10 μm to 20 μm. For example, the substrate  10  disposed below the first heatsink  31  may have a thickness corresponding to 1.25% to 5% of a maximum thickness of the substrate  10 . 
         [0025]    The substrate  10  between the first heatsink  31  and the second heatsink  32  may not be completely removed, but partially remain. Thus, when the first and second heatsinks  31  and  32  are buried into the first and second cavities  12  and  13 , it may prevent a void from occurring. 
         [0026]    The first and second electrodes  41  and  42  may extend from the bottom surface of the substrate  10  to the top surface of the substrate  10  along lateral surfaces of the substrate  10 . Also, the first and second electrodes  41  and  42  may pass through the substrate to extend from the bottom surface of the substrate  10  to the top surface of the substrate  10 . 
         [0027]    The first and second electrodes  41  and  42  may be disposed on the insulating layer  20 . The first electrode  41  may extend up to the first heatsink  31 . 
         [0028]    In this embodiment, the first electrode  41  may vertically overlap the first and second heatsinks  31  and  32  or cover surfaces of the first and second heatsinks  31  and  32 . For example, the first and second heatsinks  31  and  32  may be surrounded by the first electrode  41  and the insulating layer  20 . 
         [0029]    Thus, heat generated from the light emitting device  50  is transferred to the first heatsink  31  through the first electrode  41 , and the heat transferred to the first heatsink  31  is transferred to the second heatsink  32  adjacent to the substrate  10  and the first heatsink  31 . The heat transferred to the second heatsink  32  is effectively emitted to the outside through the first electrode  41 . 
         [0030]    The light emitting device  50  may be a light emitting diode (LED). The LED may have various structures such as a horizontal type and a vertical type. 
         [0031]    The light emitting device  50  is electrically connected to the first electrode  41  and/or the second electrode  42  through a wire  51 . In this embodiment, the light emitting device  50  has one side directly contacting the first electrode  41  and electrically connected to the first electrode  41 . Also, the light emitting device  50  is electrically connected the second electrode  42  through the wire  51 . 
         [0032]    Also, the light emitting device  50  may be connected to the first electrode  41  and/or the second electrode  42  through a conductive via passing through the substrate  10 . Alternatively, the light emitting device  50  may be connected to the first electrode  41  and/or the second electrode  42  using a flip chip manner. 
         [0033]    The light emitting device  50  may be disposed on the first heatsink  31 . Also, the light emitting device  50  may vertically overlap the first heatsink  31  to effectively transfer the heat emitted from the light emitting device  50  to the first heatsink  31 . 
         [0034]    A molding member  14  containing a phosphor may be disposed in the first cavity  11 . Also, the molding member  14  may not contain the phosphor. 
         [0035]    A method of manufacturing the light emitting device package according to an embodiment will be described in detail with reference to  FIGS. 1 to 5 . 
         [0036]    Referring to  FIG. 1 , a substrate  10  is prepared. A top surface and a bottom surface of the substrate  10  are etched to first, second, and third cavities  11 ,  12 , and  13 . 
         [0037]    A mask pattern may be formed on the substrate  10 , and then, the substrate  10  may be selectively etched using the mask pattern as an etch mask to form the first, second, and third cavities  11 ,  12 , and  13 . For example, the mask pattern may be formed of silicon nitride. 
         [0038]    The second cavity  12  and the third cavity  13  are used for forming a first heatsink  31  and a second heatsink  32 . Here, only one of the second cavity  12  and the third cavity  13  may be formed. 
         [0039]    Referring to  FIG. 2 , an insulating layer  20  is formed on a surface of the substrate  10 . The insulating layer  20  may include a Si oxide layer in which the substrate  10  formed of a Si material is oxidized. 
         [0040]    Referring to  FIG. 3 , the first heatsink  31  and the second heatsink  32  are formed in the second cavity  12  and the third cavity  13 , respectively. 
         [0041]    Seed layers may be formed in the second and third cavities  12  and  13 , and then, a plating process may be performed on the seed layers to form the first and second heatsinks  31  and  32 . 
         [0042]    Alternatively, a metal may be deposited on the second and third cavities  12  and  13  to form the first and second heatsinks  31  and  32 . 
         [0043]    Since the substrate  10  is disposed between the second cavity  12  and the third cavity  13 , the seed layers may be easily formed. Also, the first and second heatsinks  31  and  32  may be formed on the seed layers to reduce voids within the second and third cavities  12  and  13 . 
         [0044]    Referring to  FIG. 4 , a first electrode  41  and a second electrode  42 , which are electrically separated from each other are formed on the substrate  10 . 
         [0045]    Since the first and second electrodes  41  and  42  extend from a bottom surface to a top surface of the substrate, the light emitting device package may be easily installed using a surface-mount technology. 
         [0046]    The first and second electrodes  41  and  42  are formed on a bottom surface and lateral surfaces of the first cavity  11 . Thus, the first electrode  41  may cover a top surface of the first heatsink  31 . The first and second electrodes  41  and  42  may serve as a power supply function as well as a function that reflects light emitted from the light emitting device  50  to improve light efficiency. 
         [0047]    Also, the first electrode  41  may contact the first heatsink  31  to effectively transfer the heat generated from the light emitting device  50  to the first heatsink  31 . 
         [0048]    Referring to  FIG. 5 , the light emitting device  50  is disposed on the first electrode  41 . The light emitting device  50  and the second electrode  42  are electrically connected to each other using a wire  51 . 
         [0049]    Since the light emitting device  50  is formed on the first electrode  41 , the heat generated from the light emitting device  50  may be effectively transferred to the first electrode  41  and the first heatsink  31 . 
         [0050]    As described above, in the light emitting device package and the method of manufacturing the same according to an embodiment, at least one of the second cavity  12  and the third cavity  13  is formed on the substrate  10  to form at least one of the first heatsink  31  and the second heatsink  32 , which are formed of a metal material. Thus, the heat emitted from the light emitting device  50  may be quickly emitted to the outside using the first and second heatsinks  31  and  32 . 
         [0051]    Also, the first and second heatsinks  31  and  32  are vertically disposed with respect to the substrate  10  and vertically overlap each other. Thus, the heat may be effectively transferred between the first heatsink  31  and the second heatsink  32 . 
         [0052]    The method of manufacturing the light emitting device according to an embodiment may include etching a substrate  10  to form a cavity; forming a heatsink formed of a metal material within the cavity; forming first and second electrodes  41  and  42 , which are electrically separated from each other on the substrate  10 ; and installing a light emitting device  50  on the substrate  10  to electrically connect the light emitting device  50  to the first and second electrodes  41  and  42 . 
         [0053]    The etching of the substrate  10  to form the cavity may include forming at least one of a second cavity  12  in a top surface of the substrate  10  and a third cavity  13  in a bottom surface of the substrate  10 . 
         [0054]    The etching of the substrate  10  to form the cavity may include forming a first cavity  11  in the top surface of the substrate  10  and forming the second cavity  12  within the first cavity  11 . 
         [0055]    The heatsink may include at least one of a first heatsink  31  buried in the second cavity  12  and a second heatsink  32  buried in the third cavity  13 . The first heatsink  31  and the second heatsink  32  may vertically overlap each other. 
         [0056]    Another embodiment provides a lighting system which comprises the light emitting device package described above. The lighting system may include lamp, street light, back light unit, not limited thereto. 
         [0057]    Embodiments can provide the light emitting device package having a novel structure and the method of manufacturing the same. 
         [0058]    Embodiments also can provide the light emitting device package having an improved thermal emission characteristic and the method of manufacturing the same. 
         [0059]    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. 
         [0060]    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.