Abstract:
A light-emitting device package and method of manufacturing the same. The method includes: preparing a package main body comprising a plurality of cavities, wherein a light-emitting device chip is mounted in each of the cavities and a through hole is formed in a bottom of each of the cavities; preparing a fixed mold providing a first surface that blocks the cavity; coupling the package main body to the fixed mold such that an end portion of the cavity contacts the first surface; supplying an encapsulation material into the cavity through the through hole; hardening the encapsulation material; and separating the package main body from the fixed mold, and dicing the package main body into a plurality of light-emitting device packages using a singulation operation. The encapsulation material is supplied while disposing the package main body on the fixed mold so that the encapsulation material is supplied in a gravitational direction.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of Korean Patent Application No. 10-2011-0027175, filed on Mar. 25, 2011, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. 
     BACKGROUND 
     1. Field 
     The present disclosure relates to light-emitting device packages and methods of manufacturing the same, and more particularly, to light-emitting device packages and methods of manufacturing the same, in which color scattering caused due to non-uniform shrinking of an encapsulation material of the light-emitting device packages is prevented. 
     2. Description of the Related Art 
     A light emitting diode (LED) is a semiconductor device capable of emitting light of various colors via a light emitting source that includes a PN junction of compound semiconductors. The LED has a long life span, is compact and light, and has intense optical directivity, and thus can be driven at a low voltage. In addition, the LED is rigid against impacts or vibrations, does not require a preheating time or complicated driving, and may be packaged in various forms, and thus can be applied for various purposes. 
     A light-emitting device package is manufactured by coating a light-emitting device chip such as a LED with an encapsulation material in a package main body. 
     A method of manufacturing a LED package includes a die bonding operation in which a LED chip is adhered to a substrate using an adhesive, a wire bonding operation providing an electric wiring on the LED chip, and an encapsulating operation in which the LED chip is encapsulated to protect and electrically insulate the LED chip from the external environment. 
     The encapsulating operation may include coating a structure having a cavity or a dam with silicon or epoxy by using a dispensing method. 
     In the dispensing method, an ejection amount of an encapsulation material is adjusted according to an operating duration of dispenser equipment, and for a large-scale manufacture, variation of the ejection amount is caused by deviations between dispensing equipments or a hardening degree of the encapsulation material due to an operation standby time. In addition, even though the encapsulation material is ejected such that an upper surface of the encapsulation material is flatly formed, the form of the encapsulation material after hardening may be changed to a concave form due to shrinking of the encapsulation material or scattering rate thereof, which may cause color scattering defects. 
     SUMMARY 
     Provided are light-emitting device packages and methods of manufacturing the same, whereby light-emitting device defects due to deviations in ejection amounts of an encapsulation material are prevented. 
     Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments. 
     According to an aspect of the present invention, a light-emitting device package includes: a structure having a cavity; a light-emitting device chip mounted on a bottom of the cavity; at least one through hole formed in the bottom of the cavity; and an encapsulation material that is substantially horizontally filled in the cavity, wherein the encapsulation material fills at least a portion of the through hole. 
     The structure may be a mold formed of a synthetic resin material. 
     The structure may include a substrate and a dam disposed on the substrate in the form of the cavity. 
     According to another aspect of the present invention, a method of manufacturing a light-emitting device package, includes: preparing a package main body including a plurality of cavities, wherein a light-emitting device chip is mounted in each of the cavities, wherein a through hole is formed in a bottom of the cavity; preparing a fixed mold providing a first surface that blocks the cavity; coupling the package main body to the fixed mold such that an end portion of the cavity contacts the first surface; supplying an encapsulation material into the cavity through the through hole; hardening the encapsulation material; and separating the package main body from the fixed mold, and dicing the package main body into a plurality of the light-emitting device package using a singulation operation, wherein the encapsulation material is supplied while disposing the package main body on the fixed mold so that the encapsulation material is supplied in a gravitational direction. 
     The encapsulation material may be supplied to fill the cavity and at least a portion of the through hole. 
     An amount of the encapsulation material in the through hole may be reduced in a gravitational direction when the encapsulation material shrinks during hardening. 
     A diameter of the through hole may be designed such that the encapsulation material still remains inside the through hole when the encapsulation material shrinks. 
     A plurality of through holes may be formed in the cavity. 
     The first surface may be a flat surface. 
     According to another aspect of the present invention, a method of manufacturing a light-emitting device package, includes: preparing a substrate including a plurality of light-emitting device chips mounted on a surface of the substrate, and a plurality of dams surrounding the plurality of light-emitting device chips, wherein a through hole is formed in a bottom of a cavity formed by the plurality of dams; preparing a fixed mold providing a first surface that blocks end portions of the plurality of dams to define space of the cavity; coupling the substrate to the fixed mold such that the end portions of the plurality of the dams contacts the first surface; supplying an encapsulation material into the cavity through the through hole; hardening the encapsulation material; and separating the substrate from the fixed mold, and dicing the substrate into a plurality of light-emitting device packages using a singulation operation, wherein the encapsulation material is supplied while disposing the substrate on the fixed mold such that the encapsulation material is supplied in a gravitational direction. 
     A groove to accommodate the dams may be formed in the fixed mold, and a bottom of the groove may include the first surface of the fixed mold. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and/or other aspects will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which: 
         FIG. 1  is a schematic cross-sectional view illustrating a light-emitting device package according to an embodiment of the present invention; 
         FIG. 2  is a schematic cross-sectional view illustrating a light-emitting device package according to another embodiment of the present invention; 
         FIGS. 3A through 3E  are cross-sectional views illustrating a method of manufacturing a light-emitting device package according to an embodiment of the present invention; and 
         FIGS. 4A through 4E  are cross-sectional views illustrating a method of manufacturing a light-emitting device package according to another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects of the present description. 
       FIG. 1  is a schematic cross-sectional view illustrating a light-emitting device package  100  according to an embodiment of the present invention. 
     Referring to  FIG. 1 , a first lead frame  121  and a second lead frame  122  are separated from each other in a cavity C (also referred to as a concave portion) formed in an upper portion of a molding member  110 . The molding member  110  includes a lower portion supporting the first and second lead frames  121  and  122  and the upper portion in which the cavity C is formed. A light-emitting device chip  130  is mounted in the cavity C. The cavity C may include a reflection surface that reflects light emitted from the light-emitting device chip  130  to the outside. The molding member  110  may be formed of a synthetic resin such as an epoxy resin, etc. The molding member  110  may be formed using a typical molding process. 
     The light-emitting device chip  130  is mounted on and electrically connected to the first lead frame  121 . For example, the light-emitting device chip  130  may be connected to the first lead frame  121  via a wire  131 . The light emitting device  130  may be bonded to the second lead frame  122  via a wire  132 . The wire  131  may also be omitted according to the structure of the light-emitting device chip  130 . 
     A through hole  114  that communicates with the cavity C is vertically formed through the molding member  110 . The through hole  114  may be formed through the second lead frame  122  as illustrated in  FIG. 1  or may be formed through the first lead frame  121 . Alternatively, the through hole  114  may be formed not to pass through the first lead frame  121  and the second lead frame  122 . 
     An encapsulation material  160  is injected into the cavity C via the through hole  114 . The encapsulation material  160  is filled in at least a portion of the  114 . A transmissive resin including a phosphor or a transparent material may be used as the encapsulation material  160  according to the color to be emitted by the light-emitting device chip  130 . The encapsulation material  160  fills the cavity C substantially horizontally. 
     Although one through hole  114  is formed in the cavity C in  FIG. 1 , the embodiment of the present invention is not limited thereto. For example, a plurality of through holes  114  may be formed in one cavity C. Also, a diameter of the through hole  114  may be designed such that the encapsulation material  160  still remains inside the through hole  114  even when the encapsulation material  160  shrinks during the manufacturing of the light-emitting device package  100 . 
       FIG. 2  is a schematic cross-sectional view illustrating a light-emitting device package  200  according to another embodiment of the present invention. 
     Referring to  FIG. 2 , a dam  250  that forms a cavity C is disposed on a substrate  210 . The substrate  210  may be formed of a ceramic or a synthetic resin or may be a printed circuit board. The dam  250  may be formed on the substrate  210  to have a circular or rectangular form. The dam  250  may be formed of epoxy or silicon. A first lead frame  221  and a second lead frame  222  are disposed on the substrate  210 . The lead frames  221  and  222  may be formed by patterning a metal thin film on the substrate  210 . 
     A light-emitting device chip  230  is mounted on and electrically connected to the first lead frame  221 . For example, the light-emitting device chip  230  may be connected to the first lead frame  221  via a wire  231 . The light-emitting device chip  230  may be bonded to the second lead frame  222  via a wire  232 . 
     A through hole  214  that communicates with the cavity C is vertically formed through the substrate  210 . The through hole  214  may be formed through the second lead frame  222  as illustrated in  FIG. 2  or may be formed through the first lead frame  221 . Alternatively, the through hole  214  may be formed not to pass through the first lead frame  221  and the second lead frame  222 . 
     An encapsulation material  260  is filled in the cavity C through the through hole  214 . The encapsulation material  260  fills the cavity C substantially horizontally. The encapsulation material  260  may fill at least a portion of the through hole  214 . A transmissive resin including a phosphor or a transparent material may be used as the encapsulation material  260  according to the color to be emitted by the light-emitting device chip  230 . 
     Although one through hole  214  is formed in the cavity C in  FIG. 2 , the embodiment of the present invention is not limited thereto. For example, a plurality of through holes  214  may be formed in one cavity C. 
     As an upper surface of the cavity C is filled horizontally with the encapsulation material in the light-emitting device package  200  according to the current embodiment of the present invention, color scattering defects due to non-uniformity of the encapsulation material may be prevented. 
       FIGS. 3A through 3E  are cross-sectional views illustrating a method of manufacturing a light-emitting device package according to an embodiment of the present invention. 
     Referring to  FIG. 3A , a plurality of lead frames  320  are separated from each other in a package main body  310  in which a plurality of cavities C (or referred to as a concave portion) are formed. Each lead frame  320  is cut in a dicing operation into a first lead frame  321  and a second lead frame  322  which form a pair. 
     The package main body  310  includes a lower portion supporting the lead frames  320  and an upper portion providing the cavities C in which a light-emitting device chip  330  is mounted. The cavity C may include a reflection surface that reflects light emitted from the light-emitting device chip  330  to the outside. The package main body  310  may be formed of a synthetic resin such as an epoxy resin, etc. The package main body  310  may be formed using a typical molding process. 
     The light-emitting device chip  330  is mounted on and electrically connected to the first lead frame  321 . For example, the light-emitting device chip  330  may be connected to the first lead frame  321  via a wire  331 . The light emitting device  330  may be bonded to the second lead frame  322  via a wire  332 . The wire  331  may also be omitted according to the structure of the light-emitting device chip  330 . 
     A through hole  314  that communicates with the cavity C is vertically formed through the package main body  310 . The through hole  314  may be formed through the second lead frame  322  as illustrated in  FIG. 3A  or may be formed through the first lead frame  321 . Alternatively, the through hole  314  may be formed not to pass through the first lead frame  321  and the second lead frame  322 . 
     In  FIG. 3A , the plurality of light-emitting device chips  330  are arranged in series in the package main body  310 , but the embodiment of the present invention is not limited thereto. For example, the plurality of light-emitting device chips  330  may be arranged in a matrix arrangement. 
     Referring to  FIG. 3B , a fixed mold  350  corresponding to the package main body  310  is prepared. The fixed mold  350  may have a first surface  350   a  contacting the upper portion of the package main body  310  providing the cavities C. The fixed mold  350  has a space accommodating the package main body  310 . The first surface  350   a  may be a flat surface. 
     Next, an end portion of the upper portion of the package main body  310  is disposed to contact the first surface  350   a  of the fixed mold  350 . 
     Next, the package main body  310  is fixed on the fixed mold  350 . To this end, an upper portion of the fixed mold  350  may be formed to have the same height as the lower portion of the package main body  310 . A support portion  354  supporting the lower portion of the package main body  310  may be disposed on the upper portion of the fixed mold  350 . 
     Referring to  FIG. 3C , the upper portion of the package main body  310  is directed substantially downward, an encapsulation material  360  is injected through the through hole  314  to fill the cavity C. The encapsulation material  360  may be injected by using a typical dispenser (not shown) having a syringe  370 . The encapsulation material  360  is injected so as to fill at least a portion of the through hole  314 . The injected encapsulation material  360  fills the through hole  314  starting first from a portion contacted by the first surface  350   a  due to a gravitational effect. A transmissive resin including a phosphor or a transparent material may be used as the encapsulation material  360  according to the color to be emitted by the light-emitting device chip  330 . 
     Referring to  FIG. 3D , the encapsulation material  360  is hardened. A hardening temperature and hardening time may vary according to the encapsulation material  360  that is used, and detailed description thereof will be omitted. If the encapsulation material  360  shrinks during hardening, an amount corresponding to the shrunk encapsulation material  360  in the cavity C is compensated by the encapsulation material  360  in the through hole  314 , thus, the amount of the encapsulation material  360  in the cavity C is hardly changed. 
     Meanwhile, the light-emitting device package may be designed such that the encapsulation material  360  in the through hole  314  compensates for reduction of the encapsulation material  360  in the cavity C. Although one through hole  314  is formed in the cavity C, the embodiment of the present invention is not limited thereto. For example, a plurality of through holes  314  may be formed in a cavity C. Also, a diameter of the through hole  314  may be designed such that the encapsulation material  360  still remains inside the through hole  314  even when the encapsulation material  360  shrinks during the manufacturing of the light-emitting device package  100 . 
     Referring to  FIG. 3E , the package main body  310  is separated from the fixed mold  350 . The separated package main body  310  is diced with respect to a cutting line CL during a singulation operation, thereby manufacturing a plurality of light-emitting device packages  350 . 
     According to the method of manufacturing a light-emitting device package of the current embodiment of the present invention, as the encapsulation material  360  fills the fixed mold  350  in a gravitational direction, the encapsulation material  360  is horizontally filled according to the form of the first surface  350   a , and thus, deformation of the encapsulation material  360  due to shrinking during the hardening may be prevented. Consequently, color scattering caused due to shrinking scattering of the encapsulation material  360  in the conventional manufacturing method of the light-emitting device package may be prevented. 
       FIGS. 4A through 4E  are cross-sectional views illustrating a method of manufacturing a light-emitting device package according to another embodiment of the present invention. 
     Referring to  FIG. 4A , a dam  415  that forms a cavity C is disposed on a substrate  410 . The substrate  410  may be formed of a ceramic or a synthetic resin or may be a printed circuit board. The dam  415  may have a circular or rectangular shape, and may be formed of epoxy or silicon. A plurality of lead frames  420  are separately disposed on the substrate  410 . The lead frame  420  is cut during a dicing operation into a first lead frame  421  and a second lead frame  422  which form a pair. Alternatively, the lead frames  421  and  422  may be formed by forming a metal thin film on the substrate  410  and patterning the metal thin film. 
     A light-emitting device chip  430  is mounted on and electrically connected to the first lead frame  421 . For example, the light-emitting device chip  430  may be connected to the first lead frame  421  via a wire  431 . The light-emitting device chip  430  may be bonded to the second lead frame  422  via a wire  432 . 
     A through hole  414  that communicates with the cavity C is vertically formed through the substrate  410 . The through hole  414  may be formed through the second lead frame  422  as illustrated in  FIG. 4   a  or may be formed through the first lead frame  421 . Alternatively, the through hole  414  may be formed not to pass through the first lead frame  421  and the second lead frame  422 . 
     In  FIG. 4A , the plurality of light-emitting device chips  430  are arranged in series on the substrate  410 , but the embodiment of the present invention is not limited thereto. For example, the plurality of light-emitting device chips  430  may be arranged in a matrix arrangement. 
     Referring to  FIG. 4B , a fixed mold  450  corresponding to the substrate  410  is prepared. The fixed mol  450  have grooves  455  accommodating an end portion of the dame  415 . The groove  455  includes a first surface  455   a  which contacts the end portion of the dam  415 . The first surface  455   a  may be a flat surface. The depth of the groove  455  may be substantially the same as the height of the dam  415 . 
     Next, the end portion of the dam  415  is brought in contact with the first surface  455   a  of the fixed mold  450 . 
     Next, the substrate  410  is fixed to the fixed mold  450 . To this end, an upper portion of the fixed mold  450  may be formed to correspond to a lower surface  410   b  of the substrate  410  as illustrated in  FIG. 4B . A support portion  454  supporting the lower surface  410   b  of the substrate  410  may be disposed on the upper portion of the fixed mold  450 . 
     Referring to  FIG. 4C , the upper portion of the substrate  410  is directed substantially downward, and an encapsulation material  460  is injected through the through hole  414  to fill the cavity C. The encapsulation material  460  may be injected by using a dispenser (not shown) having a syringe  470 . The encapsulation material  460  is injected so as to fill at least a portion of the through hole  414 . The injected encapsulation material  460  fills first a portion of the cavity C contacting the first surface  455   a  due to gravitational effect. A transmissive resin including a phosphor or a transparent material may be used as the encapsulation material  460  according to the color to be emitted by the light-emitting device chip  430 . 
     Referring to  FIG. 4D , the encapsulation material  460  is hardened. A hardening temperature and hardening time may vary according to the encapsulation material  460  that is used, and detailed description thereof will be omitted. If the encapsulation material  460  shrinks during hardening, an amount of the encapsulation material  460  in the through hole  414  is reduced. 
     Meanwhile, the light-emitting device package may be designed such that the encapsulation material  460  in the through hole  414  compensates for reduction of the encapsulation in the cavity C. Although one through hole  214  is formed in the cavity C in  FIG. 4D , the embodiment of the present invention is not limited thereto. The embodiment of the present invention is not limited thereto. For example, a plurality of through holes  414  may be formed in one cavity C. Also, a diameter of the through hole  414  may be designed such that the encapsulation material  460  still remains inside the through hole  414  even when the encapsulation material  460  shrinks during the manufacturing of a light-emitting device package. 
     Referring to  FIG. 4E , the substrate  410  is separated from the fixed mold  450 . The separated substrate  410  is diced with respect to a cutting line CL in a singulation operation, thereby manufacturing a plurality of the light-emitting device packages. 
     According to the method of manufacturing a light-emitting device package of the current embodiment of the present invention, as the encapsulation material  460  fills the groove  455  of the fixed mold  450  in a gravitational direction, the encapsulation material  460  is horizontally filled according to the form of the first surface  455   a  of the fixed mold  450 , and thus, deformation of the encapsulation material  460  due to shrinking and hardening of the encapsulation material  460  may be prevented. Consequently, color scattering caused due to shrinking variation of the encapsulation material in the conventional manufacturing method of the light-emitting device package may be prevented. 
     It should be understood that the exemplary embodiments described therein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments.