Semiconductor light emitting device and semiconductor light emitting apparatus having the same

Provided is a semiconductor light emitting device. The semiconductor light emitting device may include: a light emitting structure comprising a first conductivity-type semiconductor layer having an upper surface divided into first and second regions, an active layer and a second conductivity-type semiconductor layer sequentially disposed on the second region of the first conductivity-type semiconductor layer; a first contact electrode disposed on the first region of the first conductivity-type semiconductor layer; a second contact electrode disposed on the second conductivity-type semiconductor layer; a first electrode pad electrically connected to the first contact electrode and having at least a portion disposed on the second contact electrode; a second electrode pad electrically connected to the second contact electrode; and a multilayer reflective structure interposed between the first electrode pad and the second contact electrode and comprising a plurality of dielectric layers which have different refractive indices and are alternately stacked.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority and benefit of Korean Patent Application No. 10-2014-0165567 filed on Nov. 25, 2014, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.

BACKGROUND

Apparatuses consistent with exemplary embodiments relate to a semiconductor light emitting device and a semiconductor light emitting apparatus including the same.

A light emitting diode (LED) is a device including a material emitting light when an electrical energy is applied thereto, in which energy generated through electron-hole recombination in semiconductor junction parts is converted into light to be emitted therefrom. LEDs are commonly employed as light sources in illumination devices, display devices, and the like, and thus, the development of LEDs has been accelerated.

As the development of gallium nitride (GaN)-based LEDs has recently increased, mobile keypads, turn signal lamps, camera flashes, and the like, using such gallium nitride-based LEDs, have been commercialized. Thus, development of general illumination devices using LEDs has been accelerated. Like the products to which they are applied, such as the backlight units of large TVs, the headlamps of vehicles, general illumination devices, and the like, the applications of light emitting devices are gradually moving toward large-sized products having high outputs and high degrees of efficiency.

In general, since flip-chip type LEDs have a limitation in that an electrode pad is widely disposed on a surface on which the LED is mounted, which absorbs light emitted from an active layer, external light extraction efficiency may decrease. Also, since the electrode pad is large, insulation with respect to a contact electrode having a different polarity disposed on a lower portion may not be secured.

SUMMARY

Exemplary embodiments of the inventive concept provide a scheme of reducing an amount of light absorbed by an electrode pad.

Exemplary embodiments of the inventive concept also provide a scheme of securing electrical insulation between a contact electrode and an electrode pad.

According to an aspect of an exemplary embodiment, there is provided a semiconductor light emitting device, the device may include: a light emitting structure comprising a first conductivity-type semiconductor layer having an upper surface divided into first and second regions, an active layer and a second conductivity-type semiconductor layer sequentially disposed in the second region of the first conductivity-type semiconductor layer, a first contact electrode disposed on the first region of the first conductivity-type semiconductor layer, a second contact electrode disposed on the second conductivity-type semiconductor layer, a first electrode pad electrically connected to the first contact electrode and having at least a portion disposed on the second contact electrode, a second electrode pad electrically connected to the second contact electrode, and a multilayer reflective structure interposed between the first electrode pad and the second contact electrode and comprising a plurality of dielectric layers which have different refractive indices and are alternately stacked.

The multilayer reflective structure may form a distributed Bragg reflector in which a first dielectric layer having a first refractive index and a second dielectric layer having a second refractive index are alternately stacked.

The first and second indices and thicknesses of the first and second dielectric layers of the multilayer reflective structure are adjusted to obtain a high degree of reflectivity with respect to a wavelength of light generated by the active layer.

The multilayer reflective structure is disposed on the light emitting structure to cover the light emitting structure overall and to redirect light traveling in an opposite direction of a substrate of the semiconductor light emitting device to a direction of the substrate.

The semiconductor light emitting device may further include an insulating layer disposed on the light emitting structure such that at least portions of the first and second contact electrodes are exposed.

The insulating layer may form a distributed Bragg reflector in which a plurality of dielectric layers having different refractive indices are alternately stacked.

The insulating layer may include the same material as that of the multilayer reflective structure.

The insulating layer has a substantially same thickness as a thickness of one dielectric layer of the multilayer reflective structure.

The first region may include a plurality of finger regions extending from one side of the light emitting structure to the other side thereof opposing the one side, and the first and second contact electrodes may include finger electrodes disposed in the plurality of finger regions.

The multilayer reflective structure may be disposed on the insulating layer and have a first opening exposing a region of the first contact electrode and a second opening exposing a region of the second contact electrode, and the first and second electrode pads may be connected to the first and second contact electrodes through the first and second openings, respectively.

A plurality of first and second openings may be provided, and the first and second electrode pads are connected to the first and second contact electrodes through the plurality of the first and second openings, respectively.

The first and second electrode pads may be disposed to traverse the plurality of finger regions.

The insulating layer is disposed on the multilayer reflective structure which comprises a plurality of openings disposed on the first and second contact electrodes, respectively.

The insulating layer comprises a plurality of openings disposed in positions corresponding to the first and second contact electrodes partially exposing the corresponding first and second contact electrodes.

At least a portion of the second electrode pad may be disposed on the first contact electrode, and at least a portion of the second electrode pad and the first contact electrode may be insulated by the multilayer reflective structure.

A portion of the multilayer reflective structure may be disposed to be in contact with a surface of the light emitting structure.

In the multilayer reflective structure, a plurality of dielectric layers having different refractive indices may be repeatedly stacked four to 20 times.

The plurality of dielectric layers of the multilayer reflective structure may be formed of a material selected from the group consisting of SiOx, SiNx, Al2O3, HfO, TiO2, ZrO, and combinations thereof.

The semiconductor light emitting device may further include a passivation layer which is disposed on the electrode pads and comprises a plurality of bonding regions partially exposing the first and second electrode pads.

A portion of the plurality of bonding regions of the passivation layer are disposed to not overlap a portion of the plurality of openings of the multilayer reflective structure.

The passivation layer comprises the same material as a material of the multilayer reflective structure.

The passivation layer comprises open regions partially exposing the first and second electrode pads and connecting to a probe pin to determine whether the semiconductor light emitting device is operable before being mounted.

According to another aspect of an exemplary embodiment, there is provided a semiconductor light emitting device, the device may include: a light emitting structure including a first conductivity-type semiconductor layer, an active layer, and a second conductivity-type semiconductor layer sequentially stacked, and an etched region formed by removing portions of the second conductivity-type semiconductor layer and the active layer to expose a portion of the first conductivity-type semiconductor layer, a multilayer reflective structure disposed on the light emitting structure and having a plurality of openings, first and second contact electrodes electrically connected to the first and second conductivity-type semiconductor layers and disposed in the plurality of openings, an insulating layer covering the multilayer reflective structure and the first and second contact electrodes, a first electrode pad disposed in a region of the multilayer reflective structure including a region corresponding to an upper portion of the second contact electrode, and a second electrode pad electrically connected to the second contact electrode.

Under bump metallurgy layers may be further disposed on the first and second electrode pads.

The first and second electrode pads may have regions having substantially the same level.

According to another aspect of an exemplary embodiment, there is provided a semiconductor light emitting apparatus, the apparatus may include: a package body having a lead frame, and a semiconductor light emitting device disposed on the package body and connected to the lead frame, wherein the semiconductor light emitting device includes: a light emitting structure including a first conductivity-type semiconductor layer having an upper surface divided into first and second regions, an active layer and a second conductivity-type semiconductor layer sequentially disposed on the second region of the first conductivity-type semiconductor layer, a first contact electrode disposed in the first region of the first conductivity-type semiconductor layer, a second contact electrode disposed on the second conductivity-type semiconductor layer, a first electrode pad electrically connected to the first contact electrode and having at least a portion thereof disposed on the second contact electrode, a second electrode pad electrically connected to the second contact electrode, and a multilayer reflective structure interposed between the first electrode pad and the second contact electrode and including a plurality of dielectric layers having different refractive indices and alternately stacked.

The lead frame may include first and second lead frames, and the first and second electrode pads of the semiconductor light emitting devices and the first and second lead frames may be connected via solders.

The solder may include first and second solders respectively disposed on the first and second electrode pads, and the first and second solders may have the same thickness.

The semiconductor light emitting apparatus may further include: an encapsulant covering the semiconductor light emitting device, wherein the encapsulant may contain a wavelength conversion material converting a wavelength of light generated by the semiconductor light emitting device.

The multilayer reflective structure may form a distributed Bragg reflector.

According to another aspect of an exemplary embodiment, there is provided a semiconductor light emitting device, the device may include: a light emitting structure comprising a first conductivity-type semiconductor layer, an active layer, and a second conductivity-type semiconductor layer sequentially disposed on a substrate, wherein etched regions are formed by removing portions of the second conductivity-type semiconductor layer, the active layer, and the first conductivity-type semiconductor layer to expose at least a portion of the first conductivity-type semiconductor layer; a first contact electrode which is connected to the first conductivity-type semiconductor layer through a bottom surface of the etched region and comprises a plurality of electrode pad portions and a plurality of finger portions; a second contact electrode which is connected to the second conductivity-type semiconductor layer and comprises a reflective metal layer; a multilayer reflective structure which covers the light emitting structure and comprises a structure in which a plurality of dielectric layers having different refractive indices are alternately stacked; an electrode pad disposed on the multilayer reflective structure and electrically connected to the first conductivity-type semiconductor layer and the second conductivity-type semiconductor layer through the first and second contact electrodes, respectively; and a passivation layer which is disposed on the electrode pad and comprises a plurality of bonding regions partially exposing the electrode pad.

The semiconductor light emitting device may further include an insulating layer covering the multilayer reflective structure and the first and second contact electrodes.

The semiconductor light emitting device may further include a solder pad comprising a first solder pad and a second solder pad and disposed on the first and second electrode pads which are partially exposed through the bonding regions.

The electrode pad may include at least a pair of pads to electrically insulate the first conductivity-type semiconductor layer and the second conductivity-type semiconductor layer, wherein a first electrode pad is electrically connected to the first conductivity-type semiconductor layer through the first contact electrode, a second electrode pad is electrically connected to the second conductivity-type semiconductor layer through the second contact electrode, and the first and second electrode pads are separated to be electrically insulated.

The multilayer reflective structure may form a distributed Bragg reflector by adjusting the refractive indices and thicknesses of the alternately stacked layers.

The multilayer reflective structure may include a plurality of openings, and the first and second contact electrodes are partially exposed on the first and second conductivity-type semiconductor layers through the plurality of openings.

A portion of the plurality of bonding regions of the passivation layer are disposed not to overlap the plurality of openings of the multilayer reflective structure.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Various exemplary embodiments of the inventive concept will now be described more fully with reference to the accompanying drawings in which some embodiments are shown. The inventive concept may, however, be embodied in different forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure is thorough and complete and fully conveys the inventive concept to those skilled in the art. In the drawings, the sizes and relative sizes of layers and regions may be exaggerated for clarity.

Meanwhile, when an embodiment can be implemented differently, functions or operations described in a particular block may occur in a different way from a flow described in the flowchart. For example, two consecutive blocks may be performed simultaneously, or the blocks may be performed in reverse according to related functions or operations.

A semiconductor light emitting device package according to an exemplary embodiment will be described with reference toFIGS. 1 through 2B.

FIG. 1is a plan view schematically illustrating a semiconductor light emitting device according to an exemplary embodiment,FIG. 2Ais a cross-sectional view taken along line A-A′ of the semiconductor light emitting device ofFIG. 1, andFIG. 2Bis an enlarged view of a portion “B” ofFIG. 2A.

Referring toFIGS. 1 and 2A, a semiconductor light emitting device1according to an exemplary embodiment may include a light emitting structure100, first and second contact electrodes140and150, first and second electrode pads610and620, and multilayer reflective structures300.

The light emitting structure100may have a structure in which a plurality of semiconductor layers are stacked, and may include a first conductivity-type semiconductor layer110, an active layer120, and a second conductivity-type semiconductor layer130sequentially stacked on a substrate101.

The substrate101may have an upper surface extending in x and y directions. The substrate101may be provided as a semiconductor growth substrate and may be formed of an insulating, a conductive, or a semi-conductive material, such as sapphire, silicon (Si), SiC, MgAl2O4, MgO, LiAlO2, LiGaO2, or GaN. Sapphire, commonly used as a material of a nitride semiconductor growth substrate, is a crystal having electrical insulating properties, having Hexa-Rhombo R3c symmetry, and having a lattice constant of 13,001 Å on a c-axis and 4,757 Å on an a-axis. Sapphire has a C-plane (0001), an A-plane (11-20), and an R-plane (1-102). In this case, the C-plane is mainly used as a nitride growth substrate because it facilitates the growth of a nitride thin film and is stable at high temperatures.

As illustrated in the drawings, an irregular pattern102may be formed on an upper surface of the substrate101, namely, on a growth surface of the semiconductor layers, and crystallinity, light emitting efficiency, and the like, of the semiconductor layers may be enhanced by the irregular pattern102. In the exemplary embodiment, the irregular pattern102may have a dome-like convex shape, but is not limited thereto. For example, the irregular pattern102may have various shapes, such as a quadrangular shape, a triangular shape, and the like. In addition, the irregular pattern102may be selectively formed and omitted, according to exemplary embodiments.

The substrate101may be removed later in some exemplary embodiments. That is, after the substrate101is provided as a growth substrate for growing the first conductivity-type semiconductor layer110, the active layer120, and the second conductivity-type semiconductor layer130, the substrate101may be removed through a separation process. The substrate101may be separated from the semiconductor layers through a laser lift-off (LLO) process, a chemical lift-off (CLO) process, and the like.

Although not illustrated in the drawings, a buffer layer may further be formed on an upper surface of the substrate101. The buffer layer, serving to alleviate lattice defects in the semiconductor layers grown on the substrate101, may be formed of an undoped semiconductor layer, such as a nitride. For example, the buffer layer may alleviate a difference in lattice constants between the sapphire substrate101and the first conductivity-type semiconductor layer110formed of GaN and stacked thereon to increase crystallinity of the GaN layer. The buffer layer may be undoped GaN, AlN, InGaN, and the like, and may be grown to have a thickness of tens to hundreds of angstroms at a low temperature of 500° C. to 600° C. Here, undoped refers to a semiconductor layer on which an impurity doping process has not been performed. The semiconductor layer may have an inherent level of impurity concentration. For example, when a gallium nitride semiconductor is grown by using a metal organic chemical vapor deposition (MOCVD) process, silicon (Si), or the like, used as a dopant, may be included in an amount approximately 1014to 1018/cm3therein, although not intended. However, the buffer layer is not essential and may be omitted according to exemplary embodiments.

The first conductivity-type semiconductor layer110stacked on the substrate101may be formed of a semiconductor doped with an n-type impurity, such as an n-type nitride semiconductor layer. In addition, the second conductivity-type semiconductor layer130may be formed of a semiconductor doped with a p-type impurity, such as a p-type nitride semiconductor layer. Alternatively, according to an exemplary embodiment, the positions of the first and second conductivity-type semiconductor layers110and130may be interchanged. The first and second conductivity-type semiconductor layers110and130may have an empirical formula of AlxInyGa(1−x−y)N, where 0≦x<1, 0≦y<1, and 0≦x+y<1, and may be, for example, GaN, AlGaN, InGaN, or AlInGaN.

The active layer120disposed between the first and second conductivity-type semiconductor layers110and130may emit light having a predetermined level of energy generated by electron-hole recombination. The active layer120may include a material having a smaller energy band gap than the first and second conductivity-type semiconductor layers110and130. For example, when the first and second conductivity-type semiconductor layers110and130are formed of a GaN-based compound semiconductor, the active layer120may include an InGaN-based compound semiconductor having a smaller energy band gap than GaN. In addition, the active layer120may have a multi-quantum well (MQW) structure, for example, an InGaN/GaN structure, in which quantum well layers and quantum barrier layers are alternately stacked. However, the active layer120may not be limited thereto, and may have a single quantum well (SQW) structure.

As illustrated inFIG. 2A, the light emitting structure100may include an etched region E, in which portions of the second conductivity-type semiconductor layer130, the active layer120, and the first conductivity-type semiconductor layer110are etched, and a plurality of mesa regions M partially demarcated by the etched region E.

The etched region E may have a gap structure removed from one side of the light emitting structure100having a quadrangular shape to the other side of the light emitting structure100opposed thereto to have a predetermined thickness and length, and a plurality of etched regions E may be arranged in parallel with each other on an inner side of the quadrangular region of the light emitting structure100. Thus, the plurality of etched regions E may be surrounded by the mesa regions M.

A first contact electrode140may be disposed on an upper surface of the first conductivity-type semiconductor layer110exposed to the etched region E and connected to the first conductivity-type semiconductor layer110, and a second electrode150may be disposed on an upper surface of the plurality of mesa regions M and connected to the second conductivity-type semiconductor layer130. The first and second contact electrodes140and150may be disposed on the first surface of the semiconductor light emitting device1on which the light emitting structure100is disposed. Thus, the first and second contact electrodes140and150may be disposed to be coplanar in the LED chip10and mounted on a package body1002(to be described later) in a flip-chip manner.

As illustrated inFIG. 1, the first contact electrode140may include a plurality of pad portions141and a plurality of finger portions142having a width smaller than that of the pad portions141and extending from the plurality of pad portions141, respectively, along the etched regions E. A plurality of first contact electrodes140may be arranged to be spaced apart from one another so as to be evenly distributed on the overall first conductivity-type semiconductor layer110. Thus, a current injected to the first conductivity-type semiconductor layer110may be evenly injected across the first conductivity-type semiconductor layer110through the plurality of first contact electrodes140.

The plurality of pad portions141may be disposed to be spaced apart from one another, and the plurality of finger portions142may connect the plurality of pad portions141. The plurality of finger portions142may have different widths from one another. For example, when the first contact electrode140has two finger portions142as illustrated in the exemplary embodiment, a width of any one finger portion142may be greater than that of the other finger portion142. The width of the any one finger portion142may be adjusted in consideration of resistance of a current injected through the first contact electrode140.

The second contact electrode150may include a reflective metal layer151. In addition, the second contact electrode150may further include a coating metal layer152covering the reflective metal layer151. However, the coating metal layer152may be selectively provided, and may be omitted according to exemplary embodiments. The second contact electrode150may cover an upper surface of the second conductivity-type semiconductor layer130defining an upper surface of the mesa region M.

In order to cover the active layer120exposed to the etched region E, an insulating layer200formed of an insulating material may be provided on the light emitting structure100including a lateral surface of the mesa region M. For example, the insulating layer200may be formed of an insulating material, such as SiO2, SiN, SiOxNy, TiO2, Si3N4, Al2O3, TiN, AlN, ZrO2, TiAlN, or TiSiN. In addition, the insulating layer200may include first and second openings210and220, exposing portions of the first and second conductivity-type semiconductor layers110and130. The first and second contact electrodes140and150may be disposed within the first and second openings210and220. The insulating layer200may prevent the first and second contact electrodes140and150and the active layer120from being electrically short-circuited, and prevent the first and second conductivity-type semiconductor layers110and130from being directly connected to the first and second conductivity-type semiconductor layers110and130electrically. In addition, by disposing the insulating layer200, when a multilayer reflective structure300is deposited in a follow-up process, the multilayer reflective structure300may be easily attached. However, the insulating layer200may be selectively provided, and may be omitted according to exemplary embodiments. In addition, after the insulating layer200is deposited on the light emitting structure100, when the surface of the insulating layer200is etched using plasma, a region of the insulating layer200protruding in a direction in which plasma is irradiated is etched to a greater degree and a recessed region thereof may be etched to a lesser degree. Thus, the surface of the insulating layer200may become smoother. If the insulating layer200is smooth, when the multilayer reflective structure300is deposited on the insulating layer200, formation of a void within the multilayer reflective structure300is prevented, and quality of the multilayer reflective structure300is enhanced.

The multilayer reflective structure300may be provided on the light emitting structure100such that it covers the light emitting structure overall. The multilayer reflective structure300reflects light, among light emitted from the active layer120, traveling in the opposite direction of the substrate101, to redirect the light in a direction of the substrate101.

In general, the flip-chiptype semiconductor light emitting device emits light generated by the active layer120in a direction toward the substrate101. Thus, a large amount of light emitted in a direction toward the electrode pad400, opposite to the direction of the substrate101, may be absorbed by the semiconductor layer or the metal layer disposed above the active layer120and lost. In order to resolve the degradation of luminance caused as light is absorbed by the semiconductor layer or the metal layer, the multilayer reflective structure300is employed in the exemplary embodiment.

The multilayer reflective structure300may have a multilayer structure in which layers having different refractive indices are alternately stacked. This will be described in detail hereinafter. As illustrated inFIG. 2B, the multilayer reflective structure300may have a structure in which first dielectric layers300aand second dielectric layers300bhaving different refractive indices are alternately stacked.

By appropriately adjusting refractive indices and thicknesses of the first dielectric layers300aand second dielectric layers300b, the multilayer reflective structure300may be provided as a distributed Bragg reflector (DBR).

For example, when a wavelength of light generated by the active layer120is λ and a refractive index of a corresponding layer is n, the first dielectric layer300aand the second dielectric layer300bof the multilayer reflective structure300may have a thickness equal to λ/4n, substantially having a thickness approximately 300 Å to 900 Å. Here, in the multilayer reflective structure300, reflective indices and thicknesses of the first dielectric layer300aand the second dielectric layer300bmay be selectively designed to obtain a high degree of reflectivity (95% or greater) with respect to a wavelength of light generated by the active layer120.

Refractive indices of the first dielectric layer300aand the second dielectric layer300bmay be determined within a range from about 1.4 to 2.5. The refractive indices of the first dielectric layer300aand the second dielectric layer300bmay be smaller than that of the first conductivity-type semiconductor layer110and that of the substrate101, or may be smaller than that of the first conductivity-type semiconductor layer110or greater than that of the substrate101.

In addition, the multilayer reflective structure300may further include third to nth layers (n is a natural number equal to or greater than 4) having refractive indices different from those of the first dielectric layer300aand the second dielectric layer300b. The layers constituting the multilayer reflective structure300may have the same thickness or different thicknesses. In addition, the multilayer reflective structure300may be a structure in which the first dielectric layer300aand the second dielectric layer300bare repeatedly stacked four times to 20 times.

The multilayer reflective structure300may be formed of a material having insulating properties and light transmission characteristics, and may be formed of an inorganic material or an organic material. For example, the multilayer reflective structure300may include a silicon oxide or a silicon nitride having insulating properties and light transmission characteristics, and may be formed of SiO2, SiN, SiOxNy, TiO2, Si3N4, Al2O3, TiN, AlN, ZrO2, TiAlN, or TiSiN. The multilayer reflective structure300may include a plurality of openings310and320disposed on each of the first contact electrode140and the second contact electrode150. The plurality of openings310and320may be provided in positions corresponding to each of the first contact electrode140and the second contact electrode150to partially expose the first contact electrode140and the second contact electrode150.

Among the plurality of openings310and320, the opening310disposed on the first contact electrode140may only expose the pad portion141among the pad portions141and the finger portions142in the first contact electrode140. Thus, the plurality of openings310and320may be disposed in a position corresponding to the pad portion141on the first contact electrode140. Such a disposition of the multilayer reflective structure300may be variously modified.FIG. 3Ais a modified example of the semiconductor light emitting device ofFIG. 2A, andFIG. 3Bis an enlarged view of a portion “C” ofFIG. 3A. The same reference numerals as those ofFIGS. 1 through 2Bdenote the same elements, and thus, redundant descriptions will be omitted.

As illustrated inFIGS. 3A and 3B, a stacking order of the insulating layer200and the multilayer reflective structure300is interchanged, compared with the exemplary embodiment described above. Thus, the openings310and320are disposed in the multilayer reflective structure300, and the first and second contact electrodes140and150are disposed in the openings310and320. In addition, the openings210and220disposed on the insulating layer200may be provided in positions corresponding to each of the first and second contact electrodes140and150to partially expose the corresponding first and second contact electrodes140and150. Since the insulating layer200is not disposed before the multilayer reflective structure300is disposed, adhesive properties of the multilayer reflective structure300may be reduced. However, since light may be reflected from the multilayer reflective structure300before passing through the insulating layer200, an amount of light reflected from the multilayer reflective structure300may increase.

FIG. 4Ais another modified example of the semiconductor light emitting device ofFIG. 2A, andFIG. 4Bis an enlarged view of a portion “D” ofFIG. 4A. The same reference numerals as those ofFIGS. 1 through 2Bdenote the same elements, and thus, redundant descriptions will be omitted.

As illustrated inFIGS. 4A and 4B, only the multilayer reflective structure300is stacked without the insulating layer200, compared with the exemplary embodiment described above. In this case, since the insulating layer200is not disposed before the multilayer reflective structure300is disposed, adhesive properties of the multilayer reflective structure300may be reduced. However, since light may be reflected from the multilayer reflective structure300before passing through the insulating layer200, an amount of light reflected from the multilayer reflective structure300may increase. In addition, since the insulating layer is not disposed, the manufacturing process may be facilitated, compared with the exemplary embodiment described above.

FIG. 5Ais another modified example of the semiconductor light emitting device ofFIG. 2A, andFIG. 5Bis an enlarged view of a portion “E” ofFIG. 5A. The same reference numerals as those ofFIGS. 1 through 2Bdenote the same elements, and thus, redundant descriptions will be omitted.

As illustrated inFIGS. 5A and 5B, the insulating layer200is thinner, compared with the exemplary embodiment described above. If the thickness of the insulating layer200is substantially equal to that of the second dielectric layer300bof the multilayer reflective structure300and the insulating layer200is formed of the same material as that of the multilayer reflective structure300, the insulating layer200may act as a single dielectric layer forming the multilayer reflective structure300. Thus, the insulating layer200may perform the same function as that of the second dielectric layer300b. In this case, since the insulating layer200and the multilayer reflective structure300constitute a single multilayer reflective structure300′, light reflectivity may be further enhanced.

As illustrated inFIG. 2A, the electrode pad400may be provided on the multilayer reflective structure300, and may be electrically connected to the first and second conductivity-type semiconductor layers110and130through the plurality of openings310and320, respectively.

As illustrated inFIG. 2A, the electrode pad400may be insulated from the first and second conductivity-type semiconductor layers110and130by the multilayer reflective structure300covering the entirety of an upper surface of the light emitting structure100. The electrode pad400may be connected to the first contact electrode140and the second contact electrode150partially exposed through the plurality of openings310and320so as to be electrically connected to the first and second conductivity-type semiconductor layers110and130.

Electrical connections between the electrode pad400and the first and second conductivity-type semiconductor layers110and130may be variously adjusted by the plurality of openings310and320provided in the multilayer reflective structure300. For example, electrical connections between the electrode pad400and the first and second conductivity-type semiconductor layers110and130may be variously modified according to the number and positions of the plurality of openings310and320.

The electrode pad400may include at least a pair of a first electrode pad410and a second electrode pad420. That is, the first electrode pad410may be electrically connected to the first conductivity-type semiconductor layer110through the first contact electrode140, and the second electrode pad420may be electrically connected to the second conductivity-type semiconductor layer130through the second contact electrode150. In this case, the opening310exposing the first contact electrode140may be disposed in a position in which the opening310overlaps the first electrode pad410, and the opening320exposing the second contact electrode150may be disposed in a position in which the opening320overlaps the second electrode pad420. The first and second electrode pads410and420may be separated and electrically insulated from each other.

The electrode pad400may be formed of, for example, a material including at least one of gold (Au), tungsten (W), platinum (Pt), silicon (Si), iridium (Ir), silver (Ag), copper (Cu), nickel (Ni), titanium (Ti), chromium (Cr), and alloys thereof.

The first contact electrode140, which is disposed in a position in which the second electrode pad420is positioned thereon to overlap the second electrode pad420, may need to be prevented from being electrically connected to the second electrode pad420. To this end, the multilayer reflective structure300may not have the opening310exposing the pad portion141of the first contact electrode140on the position overlapping the second electrode pad420.

As illustrated inFIG. 1, when the first contact electrode140includes three pad portions141and two finger portions142, the openings310exposing the pad portions141may only be provided on the two pad portions141disposed in positions in which the two pad portions141overlap the first electrode pad410, and may not be provided on the other pad portion141disposed in a position in which the pad portion141overlaps the second electrode pad420. Thus, the pad portion141of the first contact electrode140positioned below the first electrode pad410may be connected to the first metal electrode pad410through the opening310, but since the opening310is not provided on the pad portion141positioned below the second electrode pad420, the pad portion141and the second electrode pad420may be electrically insulated from one another. As a result, through the arrangement of the plurality of openings310and320respectively exposing the first contact electrode140and the second contact electrode150, the first electrode pad410may be connected to the first contact electrode140and the second electrode pad420may be connected to the second contact electrode150.

A passivation layer500may be provided on the electrode pad400and cover the entirety of the electrode pad400. The passivation layer500may include a bonding region510partially exposing the electrode pad400.

A plurality of bonding regions510may be provided to partially expose the first electrode pad410and the second electrode pad420. In this case, some of the plurality of bonding regions510may not overlap some of the plurality of openings310and320of the multilayer reflective structure300. For example, as illustrated inFIG. 2A, some of the bonding regions510partially exposing the second electrode pad420may not overlap some of the opening320partially exposing the second contact electrode150. That is, the bonding region510is not positioned above the opening320in a vertical direction. The bonding region510partially exposing the first electrode pad410may partially overlap the opening310partially exposing the first contact electrode140.

In the present exemplary embodiment, two bonding regions410are disposed to be parallel, but the number and dispositional form of the bonding regions510are not limited thereto and may be variously modified.

The passivation layer500may be formed of the same material as that of the multilayer reflective structure300.

The passivation layer500may further include open regions partially exposing the first and second electrode pads410and420, similarly to the bonding regions510. The open regions510may be provided as regions connected to a probe pin (not shown) in order to determine whether the semiconductor light emitting device properly operates before being mounted.

The solder pads600may be disposed in the bonding regions510. The solder pads600may include a first solder pad610and a second solder pad620to be respectively connected to the first and second electrode pads410and420partially exposed through the bonding regions510. The solder pads600may be electrically connected to the first conductivity-type semiconductor layer110and the second conductivity-type semiconductor layer130through the electrode pads400. The solder pads600may be formed of a material including at least one of materials, such as nickel (Ni), gold (Au), or copper (Cu), and alloys thereof.

The first solder pad610and the second solder pad620may be, for example, under bump metallurgy (UBM) layers. A single first solder pad and a single second solder pad or a plurality of first solder pads and a plurality of second solder pads may be provided.

A modified example of the solder pads600will be described with reference toFIG. 13. Only a modified example of the second solder pad620is illustrated inFIG. 13, but the first solder pad610may also be modified in the same manner.

FIG. 13is a view illustrating a modified example of the solder pad620ofFIG. 2A.

The second solder pad620may increase interface bonding force between the second electrode pad420of the semiconductor device and a solder bump S2and provide an electrical path. In addition, the second solder pad620may prevent solder from being spread to an electrode during a reflow process. That is, the second solder pad620may prevent a component of the solder from permeating into the second electrode pad420.

The second solder pad620may include a first surface620apositioned on the opposite side of the surface of the second electrode pad420and disposed to be in contact with an intermetallic compound (IMC)624above the second electrode pad420and a second surface620bextending from the edge of the first surface620aand connected to the second electrode pad420.

The first surface620amay have an overall flat structure, and define an upper surface of the second solder pad620. The second surface620bmay have a structure gently sloped toward the second electrode pad420from the first surface620a, and define the side of the second solder pad620.

The second solder pad620may be formed of a metal for forming an electrical connection with the second electrode pad420.

For example, the second solder pad620may have a multilayer structure including a titanium (Ti) layer621in contact with the second electrode pad420and a nickel (NI) layer622disposed on the titanium (Ti) layer621. In addition, although not shown, the second solder pad620may have a multilayer structure including a copper layer disposed on the titanium layer621, instead of the nickel layer622.

In the present exemplary embodiment, the second solder pad620has the multilayer structure of titanium (Ti) and nickel (Ni), but is not limited thereto. For example, the second solder pad620may have a multilayer structure including a chromium (Cr) layer in contact with the second electrode pad420and a nickel (Ni) layer disposed on the chromium layer or a multilayer structure including a chromium layer and a copper (Cu) layer disposed on the chromium layer.

In addition, in the present exemplary embodiment, the second solder pad620has a multilayer structure, but is not limited thereto. For example, the second solder pad620may have a monolayer structure including a nickel layer or a copper layer.

The second solder pad620may be formed through a process such as sputtering, e-beam deposition, or plating.

The intermetallic compound (IMC)624may be formed on a first surface620aof the second solder pad620. The intermetallic compound (IMC)624may be formed during a reflow process of forming the solder bump S2. The intermetallic compound (IMC)624may be formed as a tin (Sn) component of the solder reacts with the metal, for example, nickel (Ni), of the second solder pad620, and may form a binary-system tin-nickel alloy.

The solder bump S2may be bonded to the second solder pad620by the medium of the intermetallic compound (IMC)624. That is, the solder bump S2may be firmly bonded to the second solder pad620by the means of the intermetallic compound (IMC)624serving as an adhesive.

The solder bump S2may be formed by reflowing solder placed on the second solder pad620. As the solder, for example, general SAC305 (Sn96.5Ag3.0Cu0.5) may be used.

A barrier layer623may be formed to cover a second surface620bof the second solder pad620. The barrier623may minimize wettability with respect to the solder bump S2, blocking spreading of the intermetallic compound (IMC)624and the solder bump S2to the second surface620b. This may be achieved by forming the barrier layer623with a material having sufficiently minimized wettability with respect to the intermetallic compound (IMC)624and the solder bump S2.

The barrier layer623may be an oxide layer containing at least one of elements of the second solder pad620. For example, the barrier layer623may be an oxide film containing at least one element among nickel (Ni) and copper (Cu).

The barrier layer623may be formed by oxidizing the second surface620bof the second solder pad620by performing, for example, thermal oxidation or plasma oxidation.

The passivation layer500may be disposed around the second solder pad620on the second electrode pad420. The passivation layer500may be formed of, for example, SiO2.

The passivation layer500may be spaced apart from the second solder pad620on the second electrode pad400by a predetermined interval so as not to be in contact with the second solder pad620. The passivation layer500may have a thin film structure and have a height lower than that of the second solder pad620. That is, with respect to the surface of the second electrode pad420, the first surface620aof the second solder pad620may be disposed in a position higher than an upper surface of the passivation layer500.

In the present exemplary embodiment, the passivation layer500is disposed around the second solder pad620, but without being limited thereto, the passivation layer500may be selectively provided. Thus, in another exemplary embodiment, the passivation layer500may be omitted.

In the present exemplary embodiment, one first solder pad610and one second solder pad620are provided, but the number of the first solder pad610and one second solder pad620is not limited thereto. The number and dispositional structure of the first solder pad610and the second solder pad620may be adjusted according to the bonding region510. However, the first solder pad610and the second solder pad620may be determined to have substantially the same area.

Solder bumps S1and S2are disposed on the first solder pad610and the second solder pad620, and heights of the solder bumps S1and S2tend to increase in proportion to the areas thereof. Thus, if the areas of the first solder pad610and the second solder pad620are different, heights of the solder bumps S1and S2respectively disposed on the first solder pad610and the second solder pad620may become different, causing a cold-solder joint phenomenon on the side where the height of the solder bumps S1and S2is lower when the semiconductor light emitting device1is mounted on a package board in a follow-up process, which leads to a problem in which the semiconductor light emitting device1may not be turned on.

The solder bumps S1and S2may be respectively disposed on the first and second solder pads610and620and used when the semiconductor light emitting device1is mounted on a package board in a follow-up process. The solder bumps S1and S2are conductive adhesives for mounting the semiconductor light emitting device1in a flip-chip manner on a package board. Sn solder may be used as the solder bumps S1and S2, and a material, such as a slight amount of silver (Ag) or copper (Cu), may be contained in the Sn solder.

As described above, in the semiconductor light emitting device1, light moving in the opposite direction of the substrate101, among light emitted from the active layer120, may be redirected toward the substrate101to enhance light extraction efficiency, and electrical insulation may be secured between the contact electrodes and the electrode pads.

This will be described in detail with reference toFIGS. 6A and 6B.FIG. 6Ais a view illustrating an optical path of a Comparative Example, andFIG. 6Bis a view illustrating an optical path of an exemplary embodiment.

In Comparative Example ofFIG. 6A, a general insulating layer300″, instead of the multilayer reflective structure300according to the present exemplary embodiment, is disposed. In the case of a flip-chip type semiconductor light emitting device, light irradiated to an irradiation surface is emitted in a P2direction, and light moves toward a direction P1opposite to the direction P2in a region such as an upper portion of the insulating layer300″.

This appears intensively in regions such as an etched lateral region of the light emitting structure100and an edge region of the light emitting device. Such regions accounts for about 22% of the planar area of the semiconductor light emitting device, and since light is not oriented toward the irradiation surface in these regions, external light extraction efficiency of the semiconductor light emitting device is reduced.

In the present exemplary embodiment, as illustrated inFIG. 6B, the multilayer reflective structure300is disposed in the region to fundamentally block light moving in the direction P1as in Comparative Example. Thus, an amount of light irradiated to the irradiation surface may increase, thereby increasing luminance. In an experiment, the multilayer reflective structure300was formed of sixteen dielectric layers and luminance of light irradiated to the irradiation surface and that of Comparative Example were compared, and results in which luminance increased by 2% in the present exemplary embodiment were obtained.

In addition, since the multilayer reflective structure300formed by alternately stacking layers formed of an insulating material is disposed between the first electrode pad410and the second contact electrode150, which are disposed above and below the multilayer reflective structure300, electrical insulation may be more effectively made between the first electrode pad410and the second contact electrode150. Thus, in the present exemplary embodiment, luminance of the semiconductor light emitting device may be enhanced through the multilayer reflective structure300, and electrical insulation may be secured between the first electrode pad410and the second contact electrode150.

Hereinafter, a process of manufacturing the semiconductor light emitting device ofFIG. 1will be described.FIGS. 7A through 12Bare views illustrating processes of manufacturing a semiconductor light emitting device according to an exemplary embodiment. InFIGS. 7A through 12B, reference numerals the same as those ofFIGS. 1 through 2Adenote the same members, and thus, redundant descriptions thereof will be omitted.

Referring toFIGS. 7A and 7B,FIG. 7Ais a plan view of a light emitting structure100formed on a substrate101, andFIG. 7Bis a cross-sectional view taken along line A-A′ ofFIG. 7A.FIGS. 8A through 12Bare illustrated in the same manner.

The irregular pattern102may be formed on the substrate101. However, the irregular pattern102may be omitted according to exemplary embodiments. A substrate formed of a material, such as sapphire, Si, SiC, MgAl2O4, MgO, LiAlO2, LiGaO2, or GaN, as described above, may be used as the substrate101.

A first conductivity-type semiconductor layer110, an active layer120, and a second conductivity-type semiconductor layer130may be sequentially grown on the substrate101using metal-organic chemical vapor deposition (MOCVD), hydride vapor phase epitaxy (HVPE), or molecular beam epitaxy (MBE) to form the light emitting structure100having a stacked structure of a plurality of semiconductor layers. Here, the first conductivity-type semiconductor layer110and the second conductivity-type semiconductor layer130may be an n-type semiconductor layer and a p-type semiconductor layer130, respectively. In the light emitting structure100, the positions of the first conductivity-type semiconductor layer110and the second conductivity-type semiconductor layer130may be interchanged, and the second conductivity-type semiconductor layer130may first be formed on the substrate101.

Referring toFIGS. 8A and 8B, some of the second conductivity-type semiconductor layer130, the active layer120, and the first conductivity-type semiconductor layer110may be etched to expose at least some of the first conductivity-type semiconductor layer110. Accordingly, etched regions E and a plurality of mesa regions M partially demarcated by the etched regions E may be formed.

During the etching process, a mask layer may be formed in a region excluding a region in which the first conductivity-type semiconductor layer110is exposed, and wet etching or dry etching may be subsequently performed to form the mesa regions M. According to exemplary embodiments, the etching process may be performed such that the first conductivity-type semiconductor layer110is not etched and only some of an upper surface thereof is exposed.

An insulating layer200may be formed on a lateral surface of the mesa region M exposed to the etched region E through the etching process. The insulating layer200may be formed to cover the lateral surface of the mesa region M including an edge of an upper surface of the mesa region M and some of a bottom surface of the etched region E. Thus, the active layer120exposed to the etched region E may be covered by the insulating layer200so as not to be exposed outwardly. However, the insulating layer200is selectively formed and may be omitted according to exemplary embodiments.

Referring toFIGS. 9A and 9B, a first contact electrode140and a second contact electrode150may be formed in the etched region E and the mesa region M, respectively. The first contact electrode140may extend along the etched region E and may be connected to the first conductivity-type semiconductor layer110defining a bottom surface of the etched region E. The second contact electrode150may be connected to the second conductivity-type semiconductor layer130.

The first contact electrode140may include a plurality of pad portions141and a plurality of finger portions142extending from the pad portions141. The second contact electrode150may include a reflective metal layer151and a coating metal layer152covering the reflective metal layer151.

Referring toFIGS. 10A and 10B, a structure in which the multilayer reflective structure300covers the surface of the light emitting structure100may be provided.

For example, the multilayer reflective structure300may include a silicon oxide or a silicon nitride and may be formed by repeatedly depositing materials, such as SiO2, SiN, SiOxNy, TiO2, Si3N4, Al2O3, TiN, AlN, ZrO2, TiAlN, or TiSiN. This process may be performed using MOCVD, HVPE, MBE, and the like.

The multilayer reflective structure300may be provided as a multilayer structure and have a structure in which a plurality of dielectric layers having different refractive indices are alternately stacked. The multilayer reflective structure300may be provided as a distributed Bragg reflector (DBR) by appropriately adjusting the refractive indices and thicknesses of the alternately stacked layers.

The first contact electrode140and the second contact electrode150may be partially exposed on the first and second conductivity-type semiconductor layers110and130through the plurality of openings310and320.

Referring toFIGS. 11A and 11B, an electrode pad400may be formed on the multilayer reflective structure300. The electrode pad400may be connected to the first and second contact electrodes140and150exposed through the openings310and320so as to be electrically connected to the first conductivity-type semiconductor layer110and the second conductivity-type semiconductor layer130, respectively.

The electrode pad400may be provided as at least a pair in order to electrically insulate the first conductivity-type semiconductor layer110and the second conductivity-type semiconductor layer130. That is, a first electrode pad410may be electrically connected to the first conductivity-type semiconductor layer110through the first contact electrode140, a second electrode pad420may be electrically connected to the second conductivity-type semiconductor layer130through the second contact electrode150, and the first and second electrode pads410and420may be separated to be electrically insulated.

Referring toFIGS. 12A and 12B, a passivation layer500may be formed on the electrode pad400. The passivation layer500may partially expose the electrode pad400through a bonding region510.

The bonding region510may be provided in plural to partially expose the first electrode pad410and the second electrode pad420, respectively. In this case, some of the plurality of bonding regions510may be disposed not to overlap the plurality of openings310and320of the multilayer reflective structure300. For example, as illustrated inFIG. 12A, some of the bonding regions510partially exposing the second electrode pad420may not overlap with the opening320partially exposing the second contact electrode150, among the plurality of openings310and320. That is, the bonding region510is not positioned above the opening320in a vertical direction.

The passivation layer500may be formed of the same material as that of the multilayer reflective structure300.

A solder pad600including a first solder pad610and a second solder pad620may be formed on the first and second electrode pads410and420partially exposed through the bonding region510. The first solder pad610and the second solder pad620may be, for example, under-bump metallurgy (UBM) layers. The number and dispositional structure of the first solder pad610and the second solder pad620may be variously modified, without being limited thereto.

The passivation layer500may further include open regions partially exposing the first and second electrode pads410and420, similar to the bonding region510. The open regions serve to allow for determining operability of a manufactured semiconductor light emitting device before a product containing the same is released. In this case, an operation of the semiconductor light emitting device may be determined by connecting a probe pin (not shown) to the first and second electrode pads410and420exposed to the open regions and supplying driving power thereto.

FIGS. 14A and 14Bare cross-sectional views illustrating examples of a semiconductor light emitting device package employing a semiconductor light emitting device according to an exemplary embodiment.

Referring toFIG. 14A, a semiconductor light emitting device package1000may include a semiconductor light emitting device1001as a light source, a package body1002, a pair of lead frames1010, and an encapsulant1005. The semiconductor light emitting device1001may be the semiconductor light emitting device1ofFIG. 1and a detailed description thereof will be omitted.

The semiconductor light emitting device1001may be mounted on the lead frames1010and electrically connected to the lead frames1010through a conductive bonding material. As the conductive bonding material, for example, solder bumps S1and S2including Sn may be used.

The pair of lead frames1010may include a first lead frame1012and a second lead frame1014. A first solder pad610and a second solder pad620of the semiconductor light emitting device1001may be connected to the first lead frame1012and the second lead frame1014, respectively, through the solder bumps S1and S2interposed between the semiconductor light emitting device1001and the pair of lead frames1010.

The package body1002may have a reflective cup to enhance light reflection efficiency and light extraction efficiency. The encapsulant1005formed of a light-transmissive material may be formed in the reflective cup to encapsulate the semiconductor light emitting device1001.

The encapsulant1005may include a wavelength conversion material. The encapsulant1005may be formed by containing one or more types of phosphors emitting light having different wavelengths upon being excited by light generated in the semiconductor light emitting device1, in a light-transmissive resin. Accordingly, blue light, green light, or red light may be emitted, and white light, ultraviolet light, and the like, may also be emitted through adjustment.

For example, when the semiconductor light emitting device1emits blue light, blue light may be combined with yellow, green, red, and orange phosphors to emit white light. In addition, at least one of semiconductor light emitting devices1emitting purple, blue, green, red, and/or infrared light may be provided. In this case, the semiconductor light emitting device1may control a color rendering index (CRI) to range from 40 to 100, or the like, and control a color temperature ranging from 2000K to 20000K to generate various levels of white light. If necessary, the semiconductor light emitting device1may generate visible light having purple, blue, green, red, orange colors, or infrared light to adjust an illumination color according to a surrounding atmosphere or mood. In addition, the semiconductor light emitting device1may generate light having a special wavelength stimulating plant growth.

White light generated by combining yellow, green, red phosphors with a blue light emitting device and/or by combining at least one of a green light emitting device and a red light emitting device therewith, may have two or more peak wavelengths and may be positioned in a segment linking (x, y) coordinates (0.4476, 0.4074), (0.3484, 0.3516), (0.3101, 0.3162), (0.3128, 0.3292), (0.3333, 0.3333) of a CIE 1931 chromaticity diagram illustrated inFIG. 15. Alternatively, white light may be positioned in a region surrounded by a spectrum of black body radiation and the segment. A color temperature of white light corresponds to a range from about 2000K to about 20000K.

Phosphors may have the following empirical formulas and colors:

Silicates: Yellow and green (Ba,Sr)2SiO4:Eu, yellow and orange (Ba,Sr)3SiO5:Ce

Phosphor compositions should basically conform with Stoichiometry, and respective elements may be substituted with different elements of respective groups of the periodic table. For example, strontium (Sr) may be substituted with barium (Ba), calcium (Ca), magnesium (Mg), and the like, of alkali earths, and yttrium (Y) may be substituted with terbium (Tb), Lutetium (Lu), scandium (Sc), gadolinium (Gd), and the like. In addition, europium (Eu), an activator, may be substituted with cerium (Ce), terbium (Tb), praseodymium (Pr), erbium (Er), ytterbium (Yb), and the like, according to a desired energy level, and an activator may be applied alone, or a coactivator, or the like, may be additionally applied to change characteristics.

In addition, materials such as quantum dots, or the like, may be applied as materials that replace phosphors, and phosphors and quantum dots may be used in combination or alone.

A quantum dot (QD) may have a structure including a core (having a diameter ranging from 3 nm to 10 nm) such as CdSe or InP, a shell (having a thickness ranging from 0.5 nm to 2 nm) such as ZnS or ZnSe, and a ligand for stabilizing the core and the shell, and may realize various colors according to sizes.

Referring toFIG. 14B, a semiconductor light emitting device package2000may include a semiconductor light emitting device2001, a mounting board2010, and an encapsulant2005. The semiconductor light emitting device2001may be the semiconductor light emitting device1ofFIG. 1and a detailed description thereof will be omitted.

The semiconductor light emitting device2001may be mounted on the mounting board2010and electrically connected to first and second circuit patterns2012and2014. The semiconductor light emitting device2001may be encapsulated by the encapsulant2005. In this manner, a chip-on-board (COB) type package structure may be realized.

The mounting board2010may be provided as a printed circuit board (PCB), metal-core printed circuit board (MCPCB), a metal printed circuit board (MPCB), a flexible printed circuit board (FPCB), or the like, and a structure of the mounting board2010may be applied in various forms. The semiconductor light emitting device2001may be electrically connected to the first and second circuit patterns2012and2014through a conductive bonding material. As the conductive bonding material, for example, solder bumps S1and S2including Sn may be used.

FIGS. 16 and 17are views illustrating examples of backlight units employing a semiconductor light emitting device according to an exemplary embodiment.

Referring toFIG. 16, a backlight unit3000includes light sources3001mounted on a board3002and one or more optical sheets3003disposed above the light sources3001. A semiconductor light emitting device package having the structure described above with reference toFIG. 1or a structure similar thereto may be used as the light sources3001. Alternatively, a semiconductor light emitting device may be directly mounted on the board3002(a so-called COB type mounting scheme) and used as the light source.

Unlike the backlight unit3000inFIG. 16in which the light sources3001emit light toward an upper side where a liquid crystal display is disposed, a backlight unit4000as another example illustrated inFIG. 17is configured such that a light source4001mounted on a board4002emits light in a lateral direction, and the emitted light may be incident to a light guide plate4003so as to be converted into a surface light source. Light, passing through the light guide plate4003, is emitted upwards, and in order to enhance light extraction efficiency, a reflective layer4004may be disposed on a lower surface of the light guide plate4003.

FIG. 18is a view illustrating an example of a lighting device employing a semiconductor light emitting device package according to an exemplary embodiment.

Referring toFIG. 18, a lighting device5000is a bulb-type lamp and includes a light emitting module5010, a driving unit5020, and an external connection unit5030. In addition, the lighting device5000may further include external structures such as external and internal housings5040and5050and a cover5060.

The light emitting module5010may include a semiconductor light emitting device5011having a structure the same as or similar to that of the semiconductor light emitting device1ofFIG. 1and a circuit board5012on which the semiconductor light emitting device5001is mounted. In the present exemplary embodiment, a single semiconductor light emitting device5011is mounted on the circuit board5012, but a plurality of semiconductor light emitting devices may be installed as needed. In addition, the semiconductor light emitting device5011may be manufactured as a package and subsequently mounted, rather than being directly mounted on the circuit board5012.

The external housing5040may serve as a heat dissipation unit and may include a heat dissipation plate5041disposed to be in direct contact with the light emitting module5010to enhance heat dissipation and heat dissipation fins5042surrounding the lateral surfaces of the external housing5040. The cover5060may be installed on the light emitting module5010and have a convex lens shape. The driving unit5020may be installed in the internal housing5050and connected to the external connection unit5030having a socket structure to receive power from an external power source. In addition, the driving unit5020may serve to convert power into an appropriate current source for driving the semiconductor light emitting device5011and provide the same. For example, the driving unit5020may be configured as an AC-DC converter, a rectifying circuit component, and the like.

In addition, although not shown, the lighting device5000may further include a communication module.

FIG. 19is a view illustrating an example of a headlamp employing a semiconductor light emitting device according to an exemplary embodiment.

Referring toFIG. 19, a head lamp6000used as a vehicle lamp, or the like, may include a light source6001, a reflective unit6005, and a lens cover unit6004. The lens cover unit6004may include a hollow guide6003and a lens6002. The light source6001may include the semiconductor light emitting device described above or a package having the semiconductor light emitting device.

The head lamp6000may further include a heat dissipation unit6012dissipating heat generated by the light source6001outwardly. In order to effectively dissipate heat, the heat dissipation unit6012may include a heat sink6010and a cooling fan6011. In addition, the head lamp6000may further include a housing6009fixedly supporting the heat dissipation unit6012and the reflective unit6005, and the housing6009may have a body unit6006and a central hole6008formed on one surface thereof, in which the heat dissipation unit6012is coupled.

The housing6009may have a front hole6007formed on the other surface integrally connected to the one surface and bent in a right angle direction. The front hole6007may allow the reflective unit6005to be fixedly positioned above the light source6001. Accordingly, a front side is opened by the reflective unit6005, and the reflective unit6005is fixed to the housing6009such that the opened front side corresponds to the front hole6007, and light reflected by the reflective unit6005may pass through the front hole6007so as to exit outwardly.

FIGS. 20 and 21are views schematically illustrating a home network employing a lighting system using a lighting device according to an exemplary embodiment.

As illustrated inFIG. 20, a home network may include a home wireless router7000, a gateway hub7010, a ZigBee™ module7020, a lighting device7030, a garage door lock7040, a wireless door lock7050, a home application7060, a cellular phone7070, a switch7080installed on the wall, and a cloud network7090.

Operational states of a bedroom, a living room, entrance, a garage, home appliances, and illumination brightness of the lighting device7030may be automatically adjusted by utilizing home wireless communications (ZigBee™, Wi-Fi, and the like).

For example, as illustrated inFIG. 21, brightness of a lighting device8020B may be automatically adjusted using a gateway8010and a ZigBee™ module8020A according to types of programs broadcast in a TV8030or brightness of a screen. For example, when a human drama is aired so a cozy atmosphere is required, a color tone may be adjusted such that a color temperature of illumination is decreased to 5000K or below. In another example, in a light atmosphere such as a gag program, a color temperature of illumination is increased to 5000K or higher and illumination is adjusted to white illumination base on a blue color.

In addition, illumination brightness of the lighting device8020B may be controlled through a cellular phone8040using the gateway8010and the ZigBee™ module8020A.

The ZigBee™ modules7020and8020A may be integrally modularized with an optical sensor and may be integrally configured with a lighting device.

The visible light wireless communications technology is a wireless communications technology transferring information wirelessly by using light having a visible light wavelength band recognizable by the naked eye. The visible light wireless communications technology is distinguished from a wired optical communications technology in that it uses light having a visible light wavelength band and that a communications environment is based on a wireless scheme.

In addition, unlike RF wireless communications, the visible light wireless communications technology has excellent convenience and physical security properties as it can be freely used without being regulated or needing permission in the aspect of frequency usage, and is differentiated in that a user can physically check a communications link, and above all, the visible light wireless communications technology has features as a convergence technology that obtains both a unique purpose as a light source and a communications function.

LED lighting may be utilized as an internal or external light source of a vehicle. As an internal light source, the LED lighting device may be used as an indoor light, a reading light, or as various dashboard light sources of a vehicle. As an external light source, the LED lighting device may be used as a headlight, a brake light, a turn signal lamp, a fog light, a running light, and the like.

LED lighting using light within a particular wavelength band may promote plant growth and stabilize a person's mood or treat diseases. In addition, an LED may also be applicable as a light source used in robots or various mechanic facilities. Associated with low power consumption and long lifespan of LEDs, lighting may be realized by nature-friendly new and renewable energy power system such as solar cells, wind force, and the like.

As set forth above, according to exemplary embodiments, the semiconductor light emitting device in which light absorption by the electrode pads is reduced and insulation is secured between the contact electrodes and the electrode pads, and the semiconductor light emitting apparatus having the same may be provided.