WO2016085297A1 - Nitride semiconductor light emitting chip and light emitting device having the same - Google Patents

Nitride semiconductor light emitting chip and light emitting device having the same Download PDF

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Publication number
WO2016085297A1
WO2016085297A1 PCT/KR2015/012873 KR2015012873W WO2016085297A1 WO 2016085297 A1 WO2016085297 A1 WO 2016085297A1 KR 2015012873 W KR2015012873 W KR 2015012873W WO 2016085297 A1 WO2016085297 A1 WO 2016085297A1
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Prior art keywords
light emitting
layer
disposed
nitride semiconductor
molding
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PCT/KR2015/012873
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French (fr)
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Jung-Sub Song
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Iljin Led Co., Ltd.
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Publication of WO2016085297A1 publication Critical patent/WO2016085297A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/48—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
    • H01L33/58—Optical field-shaping elements
    • H01L33/60—Reflective elements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/02—Bonding areas; Manufacturing methods related thereto
    • H01L2224/04—Structure, shape, material or disposition of the bonding areas prior to the connecting process
    • H01L2224/04105—Bonding areas formed on an encapsulation of the semiconductor or solid-state body, e.g. bonding areas on chip-scale packages
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/10—Bump connectors; Manufacturing methods related thereto
    • H01L2224/15—Structure, shape, material or disposition of the bump connectors after the connecting process
    • H01L2224/16—Structure, shape, material or disposition of the bump connectors after the connecting process of an individual bump connector
    • H01L2224/161—Disposition
    • H01L2224/16151—Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
    • H01L2224/16221—Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
    • H01L2224/16225—Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being non-metallic, e.g. insulating substrate with or without metallisation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/18—High density interconnect [HDI] connectors; Manufacturing methods related thereto
    • H01L2224/20—Structure, shape, material or disposition of high density interconnect preforms
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/18—High density interconnect [HDI] connectors; Manufacturing methods related thereto
    • H01L2224/23—Structure, shape, material or disposition of the high density interconnect connectors after the connecting process
    • H01L2224/24—Structure, shape, material or disposition of the high density interconnect connectors after the connecting process of an individual high density interconnect connector
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/44—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the coatings, e.g. passivation layer or anti-reflective coating
    • H01L33/46—Reflective coating, e.g. dielectric Bragg reflector
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S362/00—Illumination
    • Y10S362/80—Light emitting diode

Definitions

  • the present invention relates to a nitride semiconductor chip, more particularly to a nitride semiconductor light emitting chip and a light emitting device having the same, capable of maximizing reflectivity as well as improving heat dissipation performance by introducing a configuration that reflects scattered light in the vicinity of edge portions of a light emitting diode.
  • a nitride semiconductor light emitting device is a device using light emitting phenomena due to electron-hole recombination.
  • As a prominent light emitting device there is a nitride semiconductor light emitting device using a nitride semiconductor such as GaN.
  • the nitride semiconductor light emitting device has a large band gap to realize light of various colors, and also superior thermal stability to be employed in a variety of application fields.
  • Such light emitting device is packaged to be commercialized.
  • the light emitting device package is manufactured through the following processes. Firstly, a light emitting device is mounted on a package substrate and then electrodes of the light emitting device are electrically connected to outside electrodes through a wiring process. After, an encapsulant including a phosphor is deposited on the package substrate and then harden to mold the light emitting device.
  • the conventional light emitting device package is disclosed in Korean Laid-upon patent No 10-2010-0038937 (Publication Date: April 15, 2010).
  • the objective of the present invention provides a nitride semiconductor light emitting chip and a light emitting device having the same, capable of maximizing reflectivity as well as improving heat dissipation performance by introducing a configuration that reflects scattered light in the vicinity of edge portions of a light emitting diode.
  • a nitride semiconductor light emitting chip comprises a light emitting diode including a light emitting structure having a first conductive type nitride layer, an active layer, and a second conductive type nitride layer which are sequentially disposed on a substrate, and a first reflective layer disposed on the second conductive type nitride layer of the light emitting structure; a molding disposed to cover side surfaces of the light emitting diode; and a second reflective layer disposed on at least part of a lower surface of the molding.
  • a nitride semiconductor light emitting device comprises a nitride semiconductor light emitting chip having a light emitting diode including a light emitting structure having a first conductive type nitride layer, an active layer, and a second conductive type nitride layer which are sequentially disposed on a substrate, and a first reflective layer disposed on the second conductive type nitride layer of the light emitting structure, a molding disposed to cover side surfaces of the light emitting diode, and a second reflective layer disposed on at least part of a lower surface of the molding; a package substrate on which the nitride semiconductor light emitting chip is mounted; and an electrode terminal disposed on the package substrate to apply an electrical signal to the package substrate and the light emitting diode chip.
  • the nitride semiconductor light emitting chip and the light emitting device having the same has a configuration in which light emitted from a light emitting structure is reflected by a first reflective layer formed on the light emitting structure and a second reflective layer formed on a lower surface of a molding, to maximize reflectivity by employing a configuration advantage capable of re-reflecting lights being scattered and dissipated in the vicinity of an edge portion of an upper surface of a light emitting diode, thereby improving light emitting efficiency.
  • the nitride semiconductor light emitting chip and the light emitting device having the same may enable light being scattered and dissipated at the edge portion of the upper surface of the light emitting diode to refract light being re-reflected to the lower surface and the side surface of the molding by the second reflective layer, into a direction of the lower surface of the light emitting diode, to thereby maximize reflectivity to improve light emitting efficiency, by forming the second reflective layer in a configuration extended to the lower surface as well as the side surface of the molding.
  • the nitride semiconductor light emitting chip and the light emitting device having the same is designed to electrically ground the second reflective layer to the first and second bonding pads, so that the second reflective layer serves as a grounding layer with respect to the first and second bonding pads when the light emitting diode operates, resulting in improvement of heat dissipation.
  • FIG, 1 is a schematic sectional view showing a nitride semiconductor light emitting chip according to one embodiment of the present invention
  • FIG. 2 is a detailed sectional view showing the nitride semiconductor light emitting chip according to one embodiment of the present invention
  • FIG. 3 is a detailed diagram showing a light emitting diode shown on FIG. 2;
  • FIG. 4 is a sectional view showing a nitride semiconductor light emitting chip according to another embodiment of the present invention.
  • FIG. 5 is a sectional view showing a nitride semiconductor light emitting device according to one embodiment of the present invention.
  • FIG. 1 is a schematic sectional view showing a nitride semiconductor light emitting chip according to one embodiment of the present invention
  • FIG. 2 is a detailed sectional view showing the nitride semiconductor light emitting chip according to one embodiment of the present invention.
  • a nitride semiconductor light emitting chip 100 according to one embodiment of the present invention comprises a light emitting diode 120, a molding 140, and a second reflective layer 160.
  • the light emitting diode 120 is comprised of an upper surface 120a, a lower surface 120b, and a side surface 120c connecting the upper surface 120a and the lower surface 120b.
  • the light emitting diode 120 is bonded so as to face the upper surface 120a to an upper surface of a package substrate (not shown).
  • the light emitting diode 120 comprises a light emitting structure 122, a first reflective layer 124, a first bonding pad 126, and a second bonding pad 127.
  • the light emitting structure 122 is comprised of a first conductive type nitride layer (not shown), an active layer (not shown), and a second conductive type nitride layer (not shown) which are formed on a substrate 121, and the detailed description will be made in below.
  • the first reflective layer 124 is disposed on an upper portion of the second conductive type nitride of the light emitting structure 122.
  • the first reflective layer 124 may have a thickness of 0.1 to 10 micrometer, and, more preferably, have a thickness of 0.1 to 5 micrometer. In case that the thickness of the first reflective layer 124 is below 0.1 micrometer, it may difficult to fully serve as a reflective layer. On the contrary, in case that the thickness of the first reflective layer 124 is over 10 micrometer, it may increase a manufacturing cost without an additional effect due to the increment of thickness as well as occur a high profile.
  • the reflective layer 124 may be comprised of a multi-layer configuration which is made of at least one among one or more species mixture selected from a group consisting of titanium (Ti), zinc (Zn), niobium (Nb), tungsten (W), tin (Sn), zirconium (Zr), strontium (Sr), tantalum (Ta), nickel (Ni), silicon (Si), silver (Ag), aluminium (Al), palladium (Pd), ruthenium (Ru), platinum (Pt), and rhodium (Rh), or at least one selected from a compound, a mixture, an oxide, a nitride, and a fluoride including at least one or more species of the group.
  • species mixture selected from a group consisting of titanium (Ti), zinc (Zn), niobium (Nb), tungsten (W), tin (Sn), zirconium (Zr), strontium (Sr), tantalum (Ta), nickel (Ni),
  • the first bonding pad 126 is disposed on the first conductive type nitride layer of the light emitting structure 122, and the second bonding pad 127 is disposed on the second conductive type nitride layer of the light emitting structure 122.
  • the first and second bonding pads 126 and 127 may be formed by one selected from an electron beam (E-Beam) deposition, a thermal evaporation, and a sputtering deposition.
  • the first and second bonding pads 126 and 127 may be formed with the same material by using the same masks.
  • the molding 140 is comprised of an upper surface 140a, a lower surface 140b opposite to the upper surface 140a, and a side surface 140c connecting the upper surface 140a and the lower surface 120b.
  • the molding 140 is disposed to cover the lower surface 120b and the side surface 120c of the light emitting diode 120.
  • the lower surface 140b of the molding 140 may be disposed on a position corresponding to the upper surface 120a of the light emitting diode 120.
  • the molding 140 may be formed so as to cover at least two surfaces of the light emitting diode 120. As shown in FIG. 2, the molding 140 may be formed to cover the lower surface 120b of the light emitting diode 120 having a hexahedron shape and four side surfaces 120c.
  • the molding 140 may be made of a pure epoxy resin. In this case, according to a light color emitted from the light emitting diode 120, it may accomplish to obtain red (R), green (G), and blue (B) lights. On the contrary, the molding 140 may be made of an epoxy resin mixed with a wavelength conversion material. In case of mixing the epoxy resin and the wavelength conversion material, it may be possible to realize a white light.
  • the molding 140 may be consisted of a resin layer constituted of at least one or more selected from a silicon resin including a polysilane and a polysiloxane, an epoxy resin including a bisphenol F-type epoxy, a bisphenol A-type epoxy, a phenol novolac type epoxy, and a cresol novolac type epoxy, and a polyimide resin.
  • the molding 140 may be made of a resin layer that further includes a wavelength conversion material for converting a wavelength of light into another wavelength.
  • the wavelength conversion material may be formed in the form of a film.
  • the molding 140 is attached on a resin layer such that it may further comprise a wavelength conversion film for converting a wavelength of light.
  • the second reflective layer 160 is disposed on the lower surface 140b of the molding 140 to be disposed at the outside of the light emitting diode 120.
  • the second reflective layer 160 is disposed on the lower surface 140b of the molding 140 adjacent to the edge portion of the upper surface 120a of the light emitting diode 120, and thus the second reflective layer 160 reflects light being scattered to the edge portion of the upper surface 120a of the light emitting diode 120, to a direction of the lower surface 120b of the light emitting diode 120, thereby increasing reflectivity efficiency of the reflected light in the direction of the lower surface 120b of the light emitting diode 120 so as to maximize light extraction efficiency.
  • the nitride semiconductor light emitting chip 100 in accordance with the present invention has a configuration in which light emitted from the light emitting structure 122 is reflected by the first reflective layer 124 formed on the light emitting structure 122 and the second reflective layer 160 formed on the lower surface 140b of the molding 140, to maximize reflectivity by employing a configuration advantage capable of re-reflecting light being scattered and dissipated in the vicinity of the edge portion of the upper surface 120a of the light emitting diode 120, thereby improving light emitting efficiency.
  • the second reflective layer 160 may be formed by one selected from screen printing, electron beam (E-Beam) deposition, thermal evaporation, sputtering deposition, and so on, and it may be preferable to form the second reflective layer 160 by the screen printing.
  • the second reflective layer 160 may be separately disposed from the first and second bonding pads 126 and 127 so as to realize an electrical insulation for them. In this case, it may be preferable to dispose the second reflective layer 160 that is slightly separated from the first and second bonding pads 126 and 127. Specifically, it may be preferable to separate the second reflective layer 160 from the first and second bonding pads 136 and 127 below 5 micro-meter.
  • the second reflective layer 160 may have a thickness of 5 nanometer to 50 micrometer, more preferably a thickness of 0.1 to 50 micrometer. In case that the second reflective layer 160 has a thickness of below 5 nanometer, it may be difficult to serve as a reflective layer. On the contrary, in case that the second reflective layer 160 has a thickness of over 50 micrometer, a step may be occurred between the second reflective layer 160 and the first and second bonding pads 126 and 127, so that it may be difficult to accomplish a compact and low-profile.
  • the second reflective layer 160 may be made of one or more species mixture selected from a group consisting of titanium (Ti), zinc (Zn), niobium (Nb), tungsten (W), tin (Sn), zirconium (Zr), strontium (Sr), tantalum (Ta), nickel (Ni), silicon (Si), silver (Ag), aluminium (Al), palladium (Pd), ruthenium (Ru), platinum (Pt), and rhodium (Rh), or have one or more multi-layer configuration including at least one selected from a compound, a mixture, an oxide, a nitride, and a fluoride which include at least one or more species among the group.
  • the multi-layer configuration may include a first layer made of the second reflective layer 160, and a second layer of which a DBR (Distributed Bragg Reflector) layer or an ODR (Omni Directional Reflector) layer being multi-layered is applied on the first layer.
  • a DBR Distributed Bragg Reflector
  • ODR Ortho Directional Reflector
  • the second layer is constituted of plural layers, each of which has a different refractive index.
  • the second layer of the second reflective layer 160 may be made of at least one selected from a compound, a mixture, an oxide, a nitride, and a fluoride including Si, Ti, V (vanadium), Cr (chromium), Mg (magnesium), Al, Zn, In (indium), C (carbon), which are applied to the DBR layer, and more preferably, may be made of one among the oxide, the nitride, and the fluoride.
  • the nitride semiconductor light emitting chip according to the aforementioned one embodiment of the present invention has a configuration in which light emitted from the light emitting structure is reflected by the first reflective layer formed on the upper portion of the light emitting structure and the second reflective layer formed on the lower portion of the molding, so that it is possible to improve light emitting efficiency by maximizing reflectivity by employing a structural advantage capable of re-reflecting light that is absorbed or scattered to be dissipated on the edge portion of the upper surface of the light emitting diode.
  • FIG. 3 is a detailed diagram showing the light emitting diode shown on FIG. 2.
  • the light emitting diode 120 may further comprise a transparent conductive layer 123, a metal diffusion barrier 125, and an insulation layer 128, as well as the light emitting structure 122, the first reflective layer 124, the first and second bonding pads 126 and 127.
  • the light emitting structure 122 includes a first conductive type nitride layer 122a, an active layer 122b, and a second conductive type nitride layer 122c, which are sequentially provided over the substrate 121.
  • the first conductive type nitride layer 122a is disposed on the substrate 121.
  • the first conductive type nitride layer 122a may have a stacked configuration in which a first layer (not shown) made of silicon-doped AlGaN and a second layer (not shown) made of undoped-GaN are alternately formed.
  • the first conductive type nitride layer 112a may be grown in a single nitride layer, but in order to accomplish a superior crystalline without cracks, it may be more preferable to grow the first conductive type nitride layer 112a in the stacked configuration by alternately forming the first and second layers (not shown) as well as a buffer layer (not shown).
  • the substrate 121 may be made of material, for example a sapphire substrate, available for growing a single crystalline nitride semiconductor.
  • the substrate 121 may be made of material selected from a zinc oxide (ZnO), a gallium nitride (GaN), a silicon (S), a silicon carbide (SiC), an aluminum nitride (AIN), and so on.
  • the light emitting diode chip 120 may further comprise a buffer layer that is interposed between the substrate 121 and the first conductive type nitride layer 122a.
  • the buffer layer is selectively provided on the upper surface of the substrate 121 so as to be formed to address a lattice mismatch between the substrate 121 and the first conductive type nitride layer 122a.
  • the buffer layer may be made of material selected from AIN, GaN, and so on.
  • the active layer 122b is formed on the first conductive type nitride layer 122a.
  • the active layer 122b may be provided between the first conductive type nitride layer 122a and the second conductive nitride layer 122c, and have a single-quantum well configuration or a multi-quantum well (MQW) configuration in which quantum well layers and quantum barriers are alternately stacked. That is, the active layer 122b has the MQW configuration by virtue of the quantum barrier made of a quaternary system AlGaInP including Al and the quantum well layer made of InGaN.
  • the active layer 122b of the MQW configuration may refrain from voluntary polarization due to stress and deformation to be generated.
  • the second conductive type nitride layer 122c may have a stacked configuration in which, for example, a first layer (not shown) of a p-type AlGaN doped with Mg as a p-type dopant, and a second layer (not shown) doped with Mg are alternately stacked. Also, in addition to the first conductive type nitride layer 122a, the second conductive type nitride layer 122c may serve as a carrier trapping layer.
  • the transparent conductive layer 123 is interposed between the second conductive type nitride layer 122c and the first reflective layer 124.
  • the transparent conductive layer 123 may be made of a transparent and conductive material, include a metal, and be a composite layer of, for example, a nickel (Ni) and a gold (Au).
  • the transparent conductive layer 123 may include an oxide and be made of a layer constituted of at least one material selected from a group comprising of, for example, ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), IZTO (Indium Zinc Tin Oxide), AZO (Aluminum Zinc Oxide), IAZO (Indium Aluminum Zinc Oxide), GZO (Gallium Zinc Oxide), IGO (Indium Gallium Oxide), IGZO (Indium Gallium Zinc Oxide), IGTO (Indium Gallium Tin Oxide), ATO (Aluminum Tin Oxide), IWO (Indium Tungsten Oxide), CIO (Copper Indium Oxide), MIO (Magnesium Indium Oxide), MgO, ZnO, In 2 O 3 , TiTaO 2 , TiNbO 2 , TiOx, RuOx, and IrOx, or a composite layer made of these layers.
  • ITO Indium Tin Oxide
  • IZO Indium Zin
  • the metal diffusion barrier 125 is disposed on the first reflective layer 124.
  • the metal diffusion barrier 125 may comprise at least one or more selected from a group consisting of Cr, Ni, Pt, Ti, Au, Cu, Ir, and W, or at least one or more selected from a compound, a mixture, an oxide, a nitride, and a fluoride.
  • the metal diffusion barrier 125 serves to prevent from degradation of the property, specifically, the reflectivity and contact resistance of the first reflective layer 124, due to a fusion at an interface between the first reflective layer 124 and the first and second bonding pads 126 and 127.
  • the insulation layer 128 serves to electrically insulate the first bonding pad 126 from the second bonding pad 127.
  • the insulation layer 128 may be made of at least one selected from a compound and an oxide, each of which includes Si, Mg, Ti, Zn, C, In, and Sn.
  • FIG. 4 there is shown a sectional view showing a nitride semiconductor light emitting chip according to another embodiment of the present invention.
  • a nitride semiconductor light emitting chip 200 has the substantially identical configuration of the nitride semiconductor light emitting chip being described and shown in FIGS. 1 and 2 according to one embodiment, so that the following detailed description will be made only on differences by omitting the aforementioned description with respect to one embodiment.
  • a second reflective layer 260 may be disposed on a lower surface 240b of a molding 240 and a side surface 240c extended from the lower surface 240b of the molding 240, respectively.
  • the second reflective layer 260 may be provided with a horizontal portion 262 disposed on the lower surface 240b of the molding 240 and a vertical portion 264 disposed on a side surface 240c of molding 240, which is extended from the lower surface 240b of the molding 240.
  • the second reflective layer 260 is formed in a configuration extended to the lower surface 240b as well as the side surface 240c of the molding 240, it is possible to enable light being scattered and dissipated at the edge portion of an upper surface 220a of the light emitting diode 220, to refract light being re-reflected into directions of the lower surface 240b and the side surface 240c of the molding 240 by the second reflective layer 260, into a direction of the lower surface 220b of the light emitting diode 220, and thus it has a structural advantage for improving reflectivity in comparison with one embodiment of the present invention.
  • the second reflective layer 260 is electrically separated from and disposed on both sides of the molding 240, thereby being electrically connected to the first and second bonding pads 226 and 227, respectively. As the second reflective layer 260 is electrically separated from and formed on the both sides of the molding 240, it is prevented from disconnection between the first and second bonding pads 226 and 227 by the second reflective layer 260.
  • the second reflective layer 260 may serve as a ground layer of the first and second bonding pad 226 and 227 when the light emitting diode 220 operates, so that the heat dissipation property may be improved.
  • the second reflective layer 260 may serve as a ground layer of the first and second bonding pad 226 and 227 when the light emitting diode 220 operates, so that the heat dissipation property may be improved.
  • there may be a structural advantage to maximize heat dissipation efficiency due to increment of area.
  • the nitride semiconductor light emitting chip may enable light being scattered and dissipated at the edge portion of an upper surface of the light emitting diode to refract light being re-reflected to the lower surface and the side surface of the molding by the second reflective layer, into a direction of the lower surface of the light emitting diode, to thereby maximize reflectivity to improve light emitting efficiency.
  • the nitride semiconductor light emitting chip according to another embodiment of the present invention is designed to electrically ground the second reflective layer to the first and second bonding pads, so that the second reflective layer serves as a grounding layer with respect to the first and second bonding pads when the light emitting diode operates, resulting in improvement of heat dissipation.
  • FIG. 5 is a sectional view showing a nitride semiconductor light emitting device according to one embodiment of the present invention.
  • a nitride semiconductor light emitting device 400 may comprise the light emitting diode 120, the molding 140, the second reflective layer 160, a package substrate 310, and an electrode terminal 320.
  • the light emitting diode 120, the molding 140, and the second reflective layer 160 are substantially identical to those shown and described with reference to FGIS. 1 and 2, so that the detailed description for them will be omitted.
  • the nitride semiconductor light emitting device 400 may employ a configuration in which light emitted from the light emitting structure 122 is reflected by the first reflective layer 124 disposed on the upper portion of the light emitting structure 122 and the second reflective layer 160 disposed on the lower surface 140b of the molding 140, so that the improvement of light emitting efficiency may accomplish by maximizing reflectivity by virtue of a structural advantage capable of re-reflecting light that is scattered and dissipated to the edge portion of the upper surface 120a of the light emitting diode 120.
  • the package substrate 310 may include an upper surface 310a and a lower surface 310b opposite to the upper surface 310a.
  • the light emitting diode 120 is bonded on the upper surface 310a of the package substrate 310.
  • the upper surface 120a of the light emitting diode 120 may be disposed to face the upper surface 310a of the package substrate 310.
  • the package substrate 310 may be made of one selected from a printed circuit board (PCB), a lead frame, a ceramic substrate, a metal substrate, and so on.
  • PCB printed circuit board
  • the electrode terminal 320 is disposed on the package substrate 310 to electrically connect the package substrate 310 to the light emitting diode 120.
  • One end of the electrode terminal 320 is electrically connected to the first and second bonding pads 126 and 127 of the light emitting diode 120, and the other end of the electrode terminal 320 is extended to the lower surface 310b of the package substrate 310.
  • An electrical connection of the eutectic bonding or the solder bonding is accomplished by a bump 330 that is made of alloy, for example Au/Sn, Pt/Au/Sn, Cr/Au/Sn, Ni/Sn, Cu/Sn, and so on, including at least two among Cr, Ti, Pt, Au, Ag, Mo, Sn, Ni, Cu.
  • the bump 330 it is preferable to employ a metal layer including at least one selected from one or more species mixture that is selected from Au and Sn.
  • Sn, Ag, Cu, and so on may be used and it may be preferable to use a AuSn alloy, a NiSn alloy, and a Agsn alloy. Therefore, the eutectic bonding as well as the solder bonding may be used for mounting the first and second bonding pads 126 and 127 of the present invention, so that one of the two soldering techniques may be employed as necessary.
  • the electrode terminal 320 may include a metal layer (not shown) made of one or more material selected from copper (Cu), nickel (Ni), chrome (Cr), molybdenum (Mo), tungsten (W), and so on, and a surface treatment layer (not shown) of which the metal layer is plated or surface-treated with one or more among tin (Sn), silver (Ag), and OSP (Organic Solderability Preservative).
  • a metal layer made of one or more material selected from copper (Cu), nickel (Ni), chrome (Cr), molybdenum (Mo), tungsten (W), and so on
  • a surface treatment layer not shown of which the metal layer is plated or surface-treated with one or more among tin (Sn), silver (Ag), and OSP (Organic Solderability Preservative).
  • the present invention provides a nitride semiconductor light emitting chip and a light emitting device having the same, capable of maximizing reflectivity as well as improving heat dissipation performance by introducing a configuration that reflects scattered light in the vicinity of edge portions of a light emitting diode.

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  • Microelectronics & Electronic Packaging (AREA)
  • Manufacturing & Machinery (AREA)
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Abstract

The present invention relates to a nitride semiconductor chip, more particularly to a nitride semiconductor light emitting chip and a light emitting device having the same, capable of maximizing reflectivity as well as improving heat dissipation performance by introducing a configuration that reflects scattered light in the vicinity of edge portions of a light emitting diode. The nitride semiconductor light emitting chip according to the present invention comprises a light emitting diode including a light emitting structure having a first conductive type nitride layer, an active layer, and a second conductive type nitride layer which are sequentially disposed on a substrate, and a first reflective layer disposed on the second conductive type nitride layer of the light emitting structure; a molding disposed to cover side surfaces of the light emitting diode; and a second reflective layer disposed on at least part of a lower surface of the molding.

Description

NITRIDE SEMICONDUCTOR LIGHT EMITTING CHIP AND LIGHT EMITTING DEVICE HAVING THE SAME
The present invention relates to a nitride semiconductor chip, more particularly to a nitride semiconductor light emitting chip and a light emitting device having the same, capable of maximizing reflectivity as well as improving heat dissipation performance by introducing a configuration that reflects scattered light in the vicinity of edge portions of a light emitting diode.
A nitride semiconductor light emitting device is a device using light emitting phenomena due to electron-hole recombination. As a prominent light emitting device, there is a nitride semiconductor light emitting device using a nitride semiconductor such as GaN. The nitride semiconductor light emitting device has a large band gap to realize light of various colors, and also superior thermal stability to be employed in a variety of application fields.
Such light emitting device is packaged to be commercialized. Conventionally, the light emitting device package is manufactured through the following processes. Firstly, a light emitting device is mounted on a package substrate and then electrodes of the light emitting device are electrically connected to outside electrodes through a wiring process. After, an encapsulant including a phosphor is deposited on the package substrate and then harden to mold the light emitting device.
Recently, there are ongoing efforts to accomplish high integration of modules and high power driving, by mounting the light emitting device on the package substrate in the form of a flip type, to thereby reduce an electrical connection path between the light emitting device and the package substrate.
The conventional light emitting device package is disclosed in Korean Laid-upon patent No 10-2010-0038937 (Publication Date: April 15, 2010).
The objective of the present invention provides a nitride semiconductor light emitting chip and a light emitting device having the same, capable of maximizing reflectivity as well as improving heat dissipation performance by introducing a configuration that reflects scattered light in the vicinity of edge portions of a light emitting diode.
According to one aspect of the present invention, a nitride semiconductor light emitting chip comprises a light emitting diode including a light emitting structure having a first conductive type nitride layer, an active layer, and a second conductive type nitride layer which are sequentially disposed on a substrate, and a first reflective layer disposed on the second conductive type nitride layer of the light emitting structure; a molding disposed to cover side surfaces of the light emitting diode; and a second reflective layer disposed on at least part of a lower surface of the molding.
According to another aspect of the present invention, a nitride semiconductor light emitting device comprises a nitride semiconductor light emitting chip having a light emitting diode including a light emitting structure having a first conductive type nitride layer, an active layer, and a second conductive type nitride layer which are sequentially disposed on a substrate, and a first reflective layer disposed on the second conductive type nitride layer of the light emitting structure, a molding disposed to cover side surfaces of the light emitting diode, and a second reflective layer disposed on at least part of a lower surface of the molding; a package substrate on which the nitride semiconductor light emitting chip is mounted; and an electrode terminal disposed on the package substrate to apply an electrical signal to the package substrate and the light emitting diode chip.
The nitride semiconductor light emitting chip and the light emitting device having the same according to the present invention has a configuration in which light emitted from a light emitting structure is reflected by a first reflective layer formed on the light emitting structure and a second reflective layer formed on a lower surface of a molding, to maximize reflectivity by employing a configuration advantage capable of re-reflecting lights being scattered and dissipated in the vicinity of an edge portion of an upper surface of a light emitting diode, thereby improving light emitting efficiency.
Also, the nitride semiconductor light emitting chip and the light emitting device having the same according to the present invention may enable light being scattered and dissipated at the edge portion of the upper surface of the light emitting diode to refract light being re-reflected to the lower surface and the side surface of the molding by the second reflective layer, into a direction of the lower surface of the light emitting diode, to thereby maximize reflectivity to improve light emitting efficiency, by forming the second reflective layer in a configuration extended to the lower surface as well as the side surface of the molding.
Further, the nitride semiconductor light emitting chip and the light emitting device having the same according to the present invention is designed to electrically ground the second reflective layer to the first and second bonding pads, so that the second reflective layer serves as a grounding layer with respect to the first and second bonding pads when the light emitting diode operates, resulting in improvement of heat dissipation.
FIG, 1 is a schematic sectional view showing a nitride semiconductor light emitting chip according to one embodiment of the present invention;
FIG. 2 is a detailed sectional view showing the nitride semiconductor light emitting chip according to one embodiment of the present invention;
FIG. 3 is a detailed diagram showing a light emitting diode shown on FIG. 2;
FIG. 4 is a sectional view showing a nitride semiconductor light emitting chip according to another embodiment of the present invention; and
FIG. 5 is a sectional view showing a nitride semiconductor light emitting device according to one embodiment of the present invention.
The above and other aspects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the following description and the drawings, the same reference numerals will be used throughout to designate the same or like components.
With reference to the accompanying drawings, a nitride semiconductor light emitting chip and a light emitting device having the same according to a preferred embodiment of the present invention will now be described in detail below.
FIG. 1 is a schematic sectional view showing a nitride semiconductor light emitting chip according to one embodiment of the present invention, and FIG. 2 is a detailed sectional view showing the nitride semiconductor light emitting chip according to one embodiment of the present invention.
Referring to FIGS. 1 and 2, a nitride semiconductor light emitting chip 100 according to one embodiment of the present invention comprises a light emitting diode 120, a molding 140, and a second reflective layer 160.
The light emitting diode 120 is comprised of an upper surface 120a, a lower surface 120b, and a side surface 120c connecting the upper surface 120a and the lower surface 120b. The light emitting diode 120 is bonded so as to face the upper surface 120a to an upper surface of a package substrate (not shown).
The light emitting diode 120 comprises a light emitting structure 122, a first reflective layer 124, a first bonding pad 126, and a second bonding pad 127.
The light emitting structure 122 is comprised of a first conductive type nitride layer (not shown), an active layer (not shown), and a second conductive type nitride layer (not shown) which are formed on a substrate 121, and the detailed description will be made in below.
The first reflective layer 124 is disposed on an upper portion of the second conductive type nitride of the light emitting structure 122. Preferably, the first reflective layer 124 may have a thickness of 0.1 to 10 micrometer, and, more preferably, have a thickness of 0.1 to 5 micrometer. In case that the thickness of the first reflective layer 124 is below 0.1 micrometer, it may difficult to fully serve as a reflective layer. On the contrary, in case that the thickness of the first reflective layer 124 is over 10 micrometer, it may increase a manufacturing cost without an additional effect due to the increment of thickness as well as occur a high profile.
The reflective layer 124 may be comprised of a multi-layer configuration which is made of at least one among one or more species mixture selected from a group consisting of titanium (Ti), zinc (Zn), niobium (Nb), tungsten (W), tin (Sn), zirconium (Zr), strontium (Sr), tantalum (Ta), nickel (Ni), silicon (Si), silver (Ag), aluminium (Al), palladium (Pd), ruthenium (Ru), platinum (Pt), and rhodium (Rh), or at least one selected from a compound, a mixture, an oxide, a nitride, and a fluoride including at least one or more species of the group.
The first bonding pad 126 is disposed on the first conductive type nitride layer of the light emitting structure 122, and the second bonding pad 127 is disposed on the second conductive type nitride layer of the light emitting structure 122. The first and second bonding pads 126 and 127 may be formed by one selected from an electron beam (E-Beam) deposition, a thermal evaporation, and a sputtering deposition. The first and second bonding pads 126 and 127 may be formed with the same material by using the same masks.
The molding 140 is comprised of an upper surface 140a, a lower surface 140b opposite to the upper surface 140a, and a side surface 140c connecting the upper surface 140a and the lower surface 120b. The molding 140 is disposed to cover the lower surface 120b and the side surface 120c of the light emitting diode 120. In this time, the lower surface 140b of the molding 140 may be disposed on a position corresponding to the upper surface 120a of the light emitting diode 120.
Specifically, it may be preferable to form the molding 140 so as to cover at least two surfaces of the light emitting diode 120. As shown in FIG. 2, the molding 140 may be formed to cover the lower surface 120b of the light emitting diode 120 having a hexahedron shape and four side surfaces 120c.
The molding 140 may be made of a pure epoxy resin. In this case, according to a light color emitted from the light emitting diode 120, it may accomplish to obtain red (R), green (G), and blue (B) lights. On the contrary, the molding 140 may be made of an epoxy resin mixed with a wavelength conversion material. In case of mixing the epoxy resin and the wavelength conversion material, it may be possible to realize a white light.
The molding 140 may be consisted of a resin layer constituted of at least one or more selected from a silicon resin including a polysilane and a polysiloxane, an epoxy resin including a bisphenol F-type epoxy, a bisphenol A-type epoxy, a phenol novolac type epoxy, and a cresol novolac type epoxy, and a polyimide resin. On the contrary, the molding 140 may be made of a resin layer that further includes a wavelength conversion material for converting a wavelength of light into another wavelength. The wavelength conversion material may be formed in the form of a film. In this case, the molding 140 is attached on a resin layer such that it may further comprise a wavelength conversion film for converting a wavelength of light.
The second reflective layer 160 is disposed on the lower surface 140b of the molding 140 to be disposed at the outside of the light emitting diode 120. The second reflective layer 160 is disposed on the lower surface 140b of the molding 140 adjacent to the edge portion of the upper surface 120a of the light emitting diode 120, and thus the second reflective layer 160 reflects light being scattered to the edge portion of the upper surface 120a of the light emitting diode 120, to a direction of the lower surface 120b of the light emitting diode 120, thereby increasing reflectivity efficiency of the reflected light in the direction of the lower surface 120b of the light emitting diode 120 so as to maximize light extraction efficiency.
The nitride semiconductor light emitting chip 100 in accordance with the present invention has a configuration in which light emitted from the light emitting structure 122 is reflected by the first reflective layer 124 formed on the light emitting structure 122 and the second reflective layer 160 formed on the lower surface 140b of the molding 140, to maximize reflectivity by employing a configuration advantage capable of re-reflecting light being scattered and dissipated in the vicinity of the edge portion of the upper surface 120a of the light emitting diode 120, thereby improving light emitting efficiency.
In this time, it may be preferable to collinearly dispose a bottom of the second reflective layer 160 in conjunction with bottoms of the first and second bonding pads 126 and 127, in order to preemptively prevent from a poor mounting and characteristic degradation due to a height difference between the second reflective layer 160 and the first and second bonding pads 126 and 127 when the light emitting diode 120 is mounted on the package substrate (not shown).
The second reflective layer 160 may be formed by one selected from screen printing, electron beam (E-Beam) deposition, thermal evaporation, sputtering deposition, and so on, and it may be preferable to form the second reflective layer 160 by the screen printing. The second reflective layer 160 may be separately disposed from the first and second bonding pads 126 and 127 so as to realize an electrical insulation for them. In this case, it may be preferable to dispose the second reflective layer 160 that is slightly separated from the first and second bonding pads 126 and 127. Specifically, it may be preferable to separate the second reflective layer 160 from the first and second bonding pads 136 and 127 below 5 micro-meter.
Preferably, the second reflective layer 160 may have a thickness of 5 nanometer to 50 micrometer, more preferably a thickness of 0.1 to 50 micrometer. In case that the second reflective layer 160 has a thickness of below 5 nanometer, it may be difficult to serve as a reflective layer. On the contrary, in case that the second reflective layer 160 has a thickness of over 50 micrometer, a step may be occurred between the second reflective layer 160 and the first and second bonding pads 126 and 127, so that it may be difficult to accomplish a compact and low-profile.
Similar to the first reflective layer 124, the second reflective layer 160 may be made of one or more species mixture selected from a group consisting of titanium (Ti), zinc (Zn), niobium (Nb), tungsten (W), tin (Sn), zirconium (Zr), strontium (Sr), tantalum (Ta), nickel (Ni), silicon (Si), silver (Ag), aluminium (Al), palladium (Pd), ruthenium (Ru), platinum (Pt), and rhodium (Rh), or have one or more multi-layer configuration including at least one selected from a compound, a mixture, an oxide, a nitride, and a fluoride which include at least one or more species among the group.
The multi-layer configuration may include a first layer made of the second reflective layer 160, and a second layer of which a DBR (Distributed Bragg Reflector) layer or an ODR (Omni Directional Reflector) layer being multi-layered is applied on the first layer.
In case that the DBR layer is used as the second layer of the second reflective layer 160, the second layer is constituted of plural layers, each of which has a different refractive index. The second layer of the second reflective layer 160 may be made of at least one selected from a compound, a mixture, an oxide, a nitride, and a fluoride including Si, Ti, V (vanadium), Cr (chromium), Mg (magnesium), Al, Zn, In (indium), C (carbon), which are applied to the DBR layer, and more preferably, may be made of one among the oxide, the nitride, and the fluoride.
The nitride semiconductor light emitting chip according to the aforementioned one embodiment of the present invention has a configuration in which light emitted from the light emitting structure is reflected by the first reflective layer formed on the upper portion of the light emitting structure and the second reflective layer formed on the lower portion of the molding, so that it is possible to improve light emitting efficiency by maximizing reflectivity by employing a structural advantage capable of re-reflecting light that is absorbed or scattered to be dissipated on the edge portion of the upper surface of the light emitting diode.
FIG. 3 is a detailed diagram showing the light emitting diode shown on FIG. 2. As shown in FIG. 3, the light emitting diode 120 according to the present invention may further comprise a transparent conductive layer 123, a metal diffusion barrier 125, and an insulation layer 128, as well as the light emitting structure 122, the first reflective layer 124, the first and second bonding pads 126 and 127.
The light emitting structure 122 includes a first conductive type nitride layer 122a, an active layer 122b, and a second conductive type nitride layer 122c, which are sequentially provided over the substrate 121.
The first conductive type nitride layer 122a is disposed on the substrate 121. The first conductive type nitride layer 122a may have a stacked configuration in which a first layer (not shown) made of silicon-doped AlGaN and a second layer (not shown) made of undoped-GaN are alternately formed. The first conductive type nitride layer 112a, of course, may be grown in a single nitride layer, but in order to accomplish a superior crystalline without cracks, it may be more preferable to grow the first conductive type nitride layer 112a in the stacked configuration by alternately forming the first and second layers (not shown) as well as a buffer layer (not shown).
In this time, the substrate 121 may be made of material, for example a sapphire substrate, available for growing a single crystalline nitride semiconductor. In addition to the sapphire substrate, the substrate 121 may be made of material selected from a zinc oxide (ZnO), a gallium nitride (GaN), a silicon (S), a silicon carbide (SiC), an aluminum nitride (AIN), and so on. Although not shown in the drawing, the light emitting diode chip 120 may further comprise a buffer layer that is interposed between the substrate 121 and the first conductive type nitride layer 122a. In this time, the buffer layer is selectively provided on the upper surface of the substrate 121 so as to be formed to address a lattice mismatch between the substrate 121 and the first conductive type nitride layer 122a. The buffer layer may be made of material selected from AIN, GaN, and so on.
The active layer 122b is formed on the first conductive type nitride layer 122a. The active layer 122b may be provided between the first conductive type nitride layer 122a and the second conductive nitride layer 122c, and have a single-quantum well configuration or a multi-quantum well (MQW) configuration in which quantum well layers and quantum barriers are alternately stacked. That is, the active layer 122b has the MQW configuration by virtue of the quantum barrier made of a quaternary system AlGaInP including Al and the quantum well layer made of InGaN. The active layer 122b of the MQW configuration may refrain from voluntary polarization due to stress and deformation to be generated.
The second conductive type nitride layer 122c may have a stacked configuration in which, for example, a first layer (not shown) of a p-type AlGaN doped with Mg as a p-type dopant, and a second layer (not shown) doped with Mg are alternately stacked. Also, in addition to the first conductive type nitride layer 122a, the second conductive type nitride layer 122c may serve as a carrier trapping layer.
The transparent conductive layer 123 is interposed between the second conductive type nitride layer 122c and the first reflective layer 124. The transparent conductive layer 123 may be made of a transparent and conductive material, include a metal, and be a composite layer of, for example, a nickel (Ni) and a gold (Au). Also, the transparent conductive layer 123 may include an oxide and be made of a layer constituted of at least one material selected from a group comprising of, for example, ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), IZTO (Indium Zinc Tin Oxide), AZO (Aluminum Zinc Oxide), IAZO (Indium Aluminum Zinc Oxide), GZO (Gallium Zinc Oxide), IGO (Indium Gallium Oxide), IGZO (Indium Gallium Zinc Oxide), IGTO (Indium Gallium Tin Oxide), ATO (Aluminum Tin Oxide), IWO (Indium Tungsten Oxide), CIO (Copper Indium Oxide), MIO (Magnesium Indium Oxide), MgO, ZnO, In2O3, TiTaO2, TiNbO2, TiOx, RuOx, and IrOx, or a composite layer made of these layers.
The metal diffusion barrier 125 is disposed on the first reflective layer 124. The metal diffusion barrier 125 may comprise at least one or more selected from a group consisting of Cr, Ni, Pt, Ti, Au, Cu, Ir, and W, or at least one or more selected from a compound, a mixture, an oxide, a nitride, and a fluoride.
The metal diffusion barrier 125 serves to prevent from degradation of the property, specifically, the reflectivity and contact resistance of the first reflective layer 124, due to a fusion at an interface between the first reflective layer 124 and the first and second bonding pads 126 and 127.
The insulation layer 128 serves to electrically insulate the first bonding pad 126 from the second bonding pad 127. The insulation layer 128 may be made of at least one selected from a compound and an oxide, each of which includes Si, Mg, Ti, Zn, C, In, and Sn.
Referring to FIG. 4, there is shown a sectional view showing a nitride semiconductor light emitting chip according to another embodiment of the present invention.
With reference to FIG. 4, a nitride semiconductor light emitting chip 200 according to another embodiment of the present invention has the substantially identical configuration of the nitride semiconductor light emitting chip being described and shown in FIGS. 1 and 2 according to one embodiment, so that the following detailed description will be made only on differences by omitting the aforementioned description with respect to one embodiment.
In the nitride semiconductor light emitting chip 200 according to another embodiment of the present invention, a second reflective layer 260 may be disposed on a lower surface 240b of a molding 240 and a side surface 240c extended from the lower surface 240b of the molding 240, respectively.
As a result, the second reflective layer 260 may be provided with a horizontal portion 262 disposed on the lower surface 240b of the molding 240 and a vertical portion 264 disposed on a side surface 240c of molding 240, which is extended from the lower surface 240b of the molding 240. In case that the second reflective layer 260 is formed in a configuration extended to the lower surface 240b as well as the side surface 240c of the molding 240, it is possible to enable light being scattered and dissipated at the edge portion of an upper surface 220a of the light emitting diode 220, to refract light being re-reflected into directions of the lower surface 240b and the side surface 240c of the molding 240 by the second reflective layer 260, into a direction of the lower surface 220b of the light emitting diode 220, and thus it has a structural advantage for improving reflectivity in comparison with one embodiment of the present invention.
Further, the second reflective layer 260 is electrically separated from and disposed on both sides of the molding 240, thereby being electrically connected to the first and second bonding pads 226 and 227, respectively. As the second reflective layer 260 is electrically separated from and formed on the both sides of the molding 240, it is prevented from disconnection between the first and second bonding pads 226 and 227 by the second reflective layer 260.
In case of preventing the disconnection between the first and second bonding pads 226 and 227, and electrically connecting the second reflective layer 260 disposed at the both sides of the molding 240 to the first and second bonding pads 226 and 227, the second reflective layer 260 may serve as a ground layer of the first and second bonding pad 226 and 227 when the light emitting diode 220 operates, so that the heat dissipation property may be improved. Specifically, in case of forming the second reflective layer 260 on the lower surface 240b and the side surface 240c of the molding 240, there may be a structural advantage to maximize heat dissipation efficiency due to increment of area.
In case that the second reflective layer is formed in a configuration extended to the side surface as well as the lower surface of the molding, the nitride semiconductor light emitting chip according to another embodiment of the aforementioned present invention may enable light being scattered and dissipated at the edge portion of an upper surface of the light emitting diode to refract light being re-reflected to the lower surface and the side surface of the molding by the second reflective layer, into a direction of the lower surface of the light emitting diode, to thereby maximize reflectivity to improve light emitting efficiency.
Also, the nitride semiconductor light emitting chip according to another embodiment of the present invention is designed to electrically ground the second reflective layer to the first and second bonding pads, so that the second reflective layer serves as a grounding layer with respect to the first and second bonding pads when the light emitting diode operates, resulting in improvement of heat dissipation.
FIG. 5 is a sectional view showing a nitride semiconductor light emitting device according to one embodiment of the present invention.
Referring to FIG. 5, a nitride semiconductor light emitting device 400 according to one embodiment of the present invention may comprise the light emitting diode 120, the molding 140, the second reflective layer 160, a package substrate 310, and an electrode terminal 320.
The light emitting diode 120, the molding 140, and the second reflective layer 160 are substantially identical to those shown and described with reference to FGIS. 1 and 2, so that the detailed description for them will be omitted.
The nitride semiconductor light emitting device 400 according to one embodiment of the present invention may employ a configuration in which light emitted from the light emitting structure 122 is reflected by the first reflective layer 124 disposed on the upper portion of the light emitting structure 122 and the second reflective layer 160 disposed on the lower surface 140b of the molding 140, so that the improvement of light emitting efficiency may accomplish by maximizing reflectivity by virtue of a structural advantage capable of re-reflecting light that is scattered and dissipated to the edge portion of the upper surface 120a of the light emitting diode 120.
The package substrate 310 may include an upper surface 310a and a lower surface 310b opposite to the upper surface 310a. The light emitting diode 120 is bonded on the upper surface 310a of the package substrate 310. As such, the upper surface 120a of the light emitting diode 120 may be disposed to face the upper surface 310a of the package substrate 310. The package substrate 310 may be made of one selected from a printed circuit board (PCB), a lead frame, a ceramic substrate, a metal substrate, and so on.
The electrode terminal 320 is disposed on the package substrate 310 to electrically connect the package substrate 310 to the light emitting diode 120. One end of the electrode terminal 320 is electrically connected to the first and second bonding pads 126 and 127 of the light emitting diode 120, and the other end of the electrode terminal 320 is extended to the lower surface 310b of the package substrate 310. In case of attaching the light emitting diode 120 on the upper surface 310a of the package substrate 310 and then electrically connecting the first and second bonding pads 126 and 127 of the light emitting diode 120 to the electrode terminal 320 by using a eutectic bonding or a solder bonding, in comparison with the conventional method using a metal wire, an electrical connection path is shorten to low an electrical resistance and a heat dissipation path is reduced so that it is possible to make a high-power device to which a high current may be applied.
An electrical connection of the eutectic bonding or the solder bonding is accomplished by a bump 330 that is made of alloy, for example Au/Sn, Pt/Au/Sn, Cr/Au/Sn, Ni/Sn, Cu/Sn, and so on, including at least two among Cr, Ti, Pt, Au, Ag, Mo, Sn, Ni, Cu. As to the bump 330, it is preferable to employ a metal layer including at least one selected from one or more species mixture that is selected from Au and Sn. In case of the eutectic bonding, Sn, Ag, Cu, and so on may be used and it may be preferable to use a AuSn alloy, a NiSn alloy, and a Agsn alloy. Therefore, the eutectic bonding as well as the solder bonding may be used for mounting the first and second bonding pads 126 and 127 of the present invention, so that one of the two soldering techniques may be employed as necessary.
Although not shown in detail in the drawing, the electrode terminal 320 may include a metal layer (not shown) made of one or more material selected from copper (Cu), nickel (Ni), chrome (Cr), molybdenum (Mo), tungsten (W), and so on, and a surface treatment layer (not shown) of which the metal layer is plated or surface-treated with one or more among tin (Sn), silver (Ag), and OSP (Organic Solderability Preservative).
Although the embodiments of the present invention are described in detail with reference to the accompanying drawings, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.
The present invention provides a nitride semiconductor light emitting chip and a light emitting device having the same, capable of maximizing reflectivity as well as improving heat dissipation performance by introducing a configuration that reflects scattered light in the vicinity of edge portions of a light emitting diode.

Claims (15)

  1. A nitride semiconductor light emitting chip, comprising:
    a light emitting diode including a light emitting structure having a first conductive type nitride layer, an active layer, and a second conductive type nitride layer which are sequentially disposed on a substrate, and a first reflective layer disposed on the second conductive type nitride layer of the light emitting structure;
    a molding disposed to cover side surfaces of the light emitting diode; and
    a second reflective layer disposed on at least part of a lower surface of the molding.
  2. The nitride semiconductor light emitting chip according to claim 1, wherein the light emitting diode includes:
    a transparent conductive layer interposed between the second conductive type nitride layer and the first reflective layer;
    a metal diffusion barrier disposed on the first reflective layer;
    an insulation layer disposed on the metal diffusion barrier;
    a first bonding pad connected electrically to the first conductive type nitride layer; and
    a second bonding pad connected electrically to the second conductive type nitride layer.
  3. The nitride semiconductor light emitting chip according to claim 2, wherein the metal diffusion barrier comprises at least one or more selected from a group consisting of Cr, Ni, Pt, Ti, Au, Cu, Ir, and W, or at least one or more selected from a compound, a mixture, an oxide, a nitride, and a fluoride.
  4. The nitride semiconductor light emitting chip according to claim 1, wherein the molding is made of a resin layer constituted of at least one or more selected from a silicon resin including a polysilane and a polysiloxane, an epoxy resin including a bisphenol F-type epoxy, a bisphenol A-type epoxy, a phenol novolac type epoxy, and a cresol novolac type epoxy, and a polyimide resin.
  5. The nitride semiconductor light emitting chip according to claim 4, wherein the molding further includes a wavelength conversion material contained in the resin layer for converting a wavelength of light into another wavelength.
  6. The nitride semiconductor light emitting chip according to claim 1, wherein the molding further includes a wavelength conversion film attached on the resin layer to convert a wavelength of light into another wavelength.
  7. The nitride semiconductor light emitting chip according to claim 2, wherein the second reflective layer is separately disposed so as to electrically insulate from the first and second bonding pads.
  8. The nitride semiconductor light emitting chip according to claim 2, wherein the second reflective layer is disposed on both sides of the molding so as to be electrically separated and is electrically connected to each of the first and second bonding pads.
  9. The nitride semiconductor light emitting chip according to claim 2, wherein the second reflective layer includes a horizontal portion disposed on a lower surface of the molding, and a vertical portion extended from the lower surface of the molding to be disposed on a side surface of the molding.
  10. The nitride semiconductor light emitting chip according to claim 1, wherein the second reflective layer has a thickness of 5 nanometer to 50 micrometer.
  11. The nitride semiconductor light emitting chip according to claim 1, wherein each of the first reflective layer and the second reflective layer includes one or more multi-layer configuration having one or more species mixture selected from a group consisting of titanium (Ti), zinc (Zn), niobium (Nb), tungsten (W), tin (Sn), zirconium (Zr), strontium (Sr), tantalum (Ta), nickel (Ni), silicon (Si), silver (Ag), aluminium (Al), palladium (Pd), ruthenium (Ru), platinum (Pt), and rhodium (Rh), or at least one selected from a compound, a mixture, an oxide, a nitride, and a fluoride, each of which includes at least one or more species among the group.
  12. The nitride semiconductor light emitting chip according to claim 1, wherein the molding is disposed to cover at least two or more surfaces of the light emitting diode.
  13. The nitride semiconductor light emitting chip according to claim 12, wherein the molding is disposed to encapsulate the side surfaces and the lower surface of the light emitting diode.
  14. A nitride semiconductor light emitting device, comprising:
    a nitride semiconductor light emitting chip having a light emitting diode including a light emitting structure having a first conductive type nitride layer, an active layer, and a second conductive type nitride layer which are sequentially disposed on a substrate, and a first reflective layer disposed on the second conductive type nitride layer of the light emitting structure,
    a molding disposed to cover side surfaces of the light emitting diode, and
    a second reflective layer disposed on at least part of a lower surface of the molding;
    a package substrate on which the nitride semiconductor light emitting chip is mounted; and
    an electrode terminal disposed on the package substrate to apply an electrical signal to the package substrate and the light emitting diode chip.
  15. A nitride semiconductor light emitting device, comprising:
    a light emitting diode including a light emitting structure having a first conductive type nitride layer, an active layer, and a second conductive type nitride layer which are sequentially disposed on a substrate, and a first reflective layer disposed on the second conductive type nitride layer of the light emitting structure;
    a package substrate on which the nitride semiconductor light emitting diode is mounted;
    a molding disposed to cover an upper surface of the package substrate and side surfaces of the light emitting diode;
    a second reflective layer disposed on at least part of a lower surface of the molding; and
    an electrode terminal disposed on the package substrate to apply an electrical signal to the light emitting diode chip.
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