KR101944410B1 - Light emitting device - Google Patents

Abstract

The light emitting device of the embodiment includes a substrate, a light emitting structure having a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer disposed under the substrate, and a light emitting structure having first and second conductivity type semiconductor layers, And first and second electrode pads arranged to be spaced apart from each other on the submount and submount having first and second regions on which the light emitting structure is mounted and electrically connected to the first and second electrode layers, At least one of the first and second electrode pads includes an upper surface having a shape inclined in a second region of the submount and reflecting the light of the light emitting structure, and the refractive index of the second conductivity type semiconductor layer is 1 conductivity type semiconductor layer, and the refractive index of the first conductivity type semiconductor layer is larger than the refractive index of the substrate.

Description

[0001]

An embodiment relates to a light emitting element.

Light emitting diodes (LEDs) are a kind of semiconductor devices that convert the electricity into infrared rays or light by using the characteristics of compound semiconductors, exchange signals, or use as a light source.

III-V nitride semiconductors (group III-V nitride semiconductors) have been spotlighted as core materials for light emitting devices such as light emitting diodes (LEDs) or laser diodes (LD) due to their physical and chemical properties.

Since such a light emitting diode does not contain environmentally harmful substances such as mercury (Hg) used in conventional lighting devices such as incandescent lamps and fluorescent lamps, it has excellent environmental friendliness, and has advantages such as long life and low power consumption characteristics. .

1 is a cross-sectional view of a conventional light emitting device having a flip bonding structure.

1, the light emitting device includes a submount 10, n-type and p-type electrode pads 22 and 24, bumps 32 and 34, n-type and p-type electrodes 42, 44, a light emitting structure 50, an AlN layer 60, and a sapphire substrate 70.

The light emitting structure 50 is composed of an n-type AlGaN layer 52, a multi quantum well (MQW) layer 54 and a p-type GaN layer 56. The holes injected through the p-type GaN layer 56 and the electrons injected through the n-type AlGaN layer 52 meet with each other in the MQW layer 54 to form an energy band unique to the material constituting the active layer 54 (UV) or deep UV (ultraviolet) light having energy determined by the wavelength of the ultraviolet light.

The refractive index of the sapphire substrate 70 is 1.76, the refractive index of the AlN layer 60 is 2.12, the refractive index of the n-type AlGaN layer 52 is 2.12 to 2.44 depending on the content of Al, The refractive index is 2.44. The light emitted from the light emitting layer 56 is emitted upward, and the refractive index of the light emitted from the light emitting layer 56 increases toward the direction in which the light travels. However, since the refractive index of the conventional light emitting device shown in FIG. 1 decreases in the upward direction, the emitted light can not be extracted in the upward direction and is trapped and lost in the light emitting structure 50, There is a problem that the light extraction efficiency is lowered because the light is emitted in the side direction (80) not the upper side.

The embodiment provides a light emitting device having a flip-bonding structure with improved light extraction efficiency.

The light emitting device of the embodiment includes: a substrate; A light emitting structure having a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer disposed under the substrate; First and second electrode layers disposed under the first and second conductive type semiconductor layers, respectively; A submount having first and second regions on which the light emitting structure is mounted; And first and second electrode pads spaced apart from each other on the submount and electrically connected to the first and second electrode layers, respectively, at least one of the first and second electrode pads being electrically connected to the submount, Wherein the second conductivity type semiconductor layer has a refractive index that is larger than a refractive index of the first conductivity type semiconductor layer, and the first conductivity type semiconductor layer has a refractive index higher than that of the first conductivity type semiconductor layer, The refractive index of the conductive type semiconductor layer is larger than the refractive index of the substrate.

At least one of the first and second electrode pads being disposed in the first region of the submount; And a second segment extending obliquely from the first segment and disposed in the second region of the submount and having the inclined upper surface.

Wherein the submount has a flat top surface in the first region and an inclined top surface in the second region, wherein at least one of the first and second electrode pads has a uniform thickness in the first and second regions Lt; / RTI > Alternatively, the submount may have a flat upper surface in the first and second regions, at least one of the first and second electrode pads having a uniform thickness in the first region, And may have an increasing thickness toward the edge to form the upper surface of the photograph.

The inclination angles of the upper surface of the first electrode pad and the upper surface of the second electrode pad may be the same or different.

The inclination angle of the upper surface may be 10 ° to 50 ° or 30 °. The inclined height of the upper surface may be 300 * tan? To 500 * tan? Nm (where? Is the inclination angle of the upper surface).

The upper surface of at least one of the first and second electrode pads may have a light reflection pattern that reflects light from the light emitting structure.

The inclined upper surface of the first and second electrode pads may be parabolic.

And a buffer layer disposed between the substrate and the light emitting structure. The refractive index of the buffer layer may be greater than the refractive index of the substrate, and the refractive index of the first conductivity type semiconductor layer may be greater than the refractive index of the buffer layer.

Since the light emitting device according to the embodiment has a part of the electrode pad disposed on the submount, the light emitted from the side of the light emitting structure can be reflected by the inclined electrode pad and travel in the upward direction, .

1 is a cross-sectional view of a conventional light emitting device having a flip bonding structure.
2 is a plan view of a light emitting device having a flip bonding structure according to an embodiment.
3A to 3D show an embodiment of a cross-sectional view taken along line 3-3 'of the light emitting device illustrated in FIG.
4A to 4I are perspective views of a light reflection pattern according to an embodiment.
5A to 5C are cross-sectional views illustrating a method of manufacturing an upper structure of a light emitting device according to an embodiment.
FIGS. 6A to 6C are cross-sectional views illustrating a manufacturing method of a lower structure of the light emitting device illustrated in FIGS. 3A and 3C.
FIGS. 7A and 7B are process cross-sectional views illustrating a method of manufacturing a lower structure of a light emitting device illustrated in FIGS. 3B and 3D.
8 is a cross-sectional view of a light emitting device package according to an embodiment.
9 is a perspective view of a lighting unit according to an embodiment.
10 is an exploded perspective view of a backlight unit according to an embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings in order to facilitate understanding of the present invention. However, the embodiments according to the present invention can be modified into various other forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. Embodiments of the invention are provided to more fully describe the present invention to those skilled in the art.

In the description of the embodiment according to the present invention, in the case of being described as being formed on the "upper" or "on or under" of each element, on or under includes both elements being directly contacted with each other or one or more other elements being indirectly formed between the two elements. Also, when expressed as "on" or "on or under", it may include not only an upward direction but also a downward direction with respect to one element.

The thickness and size of each layer in the drawings are exaggerated, omitted, or schematically shown for convenience and clarity of explanation. Also, the size of each component does not entirely reflect the actual size.

2 is a plan view of a light emitting device 100 having a flip bonding structure according to an embodiment.

3A to 3D show embodiments 100A to 100D of a cross-sectional view taken along line 3-3 'of the light emitting device 100 illustrated in FIG. 2. Reference numerals 110A and 110B denote reference numerals 100 .

The light emitting devices 100A to 100D illustrated in FIGS. 2 and 3A to 3D include LEDs using a plurality of compound semiconductor layers, for example, a compound semiconductor layer of a group III-V element, and the LEDs may be blue, A colored LED that emits light such as red light, an ultraviolet (UV) LED, a deep ultraviolet LED, or a non-polarized LED. The emitted light of the LED may be implemented using various semiconductors, but is not limited thereto.

3A, the light emitting device 100A illustrated in FIG. 3A includes a submount 110A, first and second electrode pads 122 and 124, first and second bumps 132 and 132, The first and second electrode pads 142 and 144, the light emitting structure 150, the buffer layer 160, and the substrate 170.

The buffer layer 160 is disposed between the substrate 170 and the light emitting structure 150. The substrate 170 can have a mechanical strength sufficient to separate into separate chips through a scribing process and a breaking process without causing warping of the entire nitride light emitting structure 150 . For example, the substrate 170 may be made of a light-transmitting material so that light emitted from the light emitting structure 150 can be emitted. The substrate 170 may include at least one of, for example, sapphire (Al ₂ O ₃ ), SiC, GaAs, GaN, ZnO, Si, GaP, InP and Ge.

The buffer layer 160 serves to improve the lattice mismatch between the substrate 170 and the light emitting structure 150. For example, the buffer layer 160 may include, but is not limited to, AlN or an undoped nitride. The buffer layer 160 may be omitted depending on the type of the substrate 170 and the type of the light emitting structure 150.

The light emitting structure 150 includes a first conductive semiconductor layer 152, an active layer 154, and a second conductive semiconductor layer 156 sequentially disposed under the buffer layer 160.

The first conductive semiconductor layer 152 is disposed between the buffer layer 160 and the active layer 154 and may include a semiconductor compound and may be formed of a compound semiconductor such as a group III-V or II-VI group. , A first conductive type dopant may be doped. For example, the first conductivity type semiconductor layer 152 may have a composition formula of Al _x In _y Ga _(1-xy) N (0? X? 1, 0? _Y? 1, 0? _X + Semiconductor material, InAlGaN, AlGaAs, GaP, GaAs, GaAsP, and AlGaInP. When the first conductive semiconductor layer 152 is an n-type semiconductor layer, the first conductive dopant may include n-type dopants such as Si, Ge, Sn, Se, and Te. The first conductive semiconductor layer 152 may have a single layer or a multi-layer structure, but the present invention is not limited thereto. If the light emitting device 100A illustrated in FIG. 3A is ultraviolet (UV), deep UV, or unpolarized light emitting device, the first conductivity type semiconductor layer 152 may include at least one of InAlGaN and AlGaN can do.

The active layer 154 is disposed between the first conductivity type semiconductor layer 152 and the second conductivity type semiconductor layer 156 and includes a single well structure, a multiple well structure, a single quantum well structure, A multi quantum well (MQW) structure, a quantum dot structure, or a quantum wire structure. InGaN / InGaN, GaN / AlGaN, InAlGaN / GaN, GaAs (InGaAs) / AlGaAs, GaP (InGaP) / AlGaP, but the present invention is not limited thereto. The well layer may be made of a material having an energy band gap smaller than the energy band gap of the barrier layer. In particular, the active layer 154 according to the embodiment can generate ultraviolet or deep ultraviolet light.

The second conductive type semiconductor layer 156 is disposed under the active layer 154 and may include a semiconductor compound. The second conductive semiconductor layer 156 may be formed of a compound semiconductor such as a Group III-V or a Group II-VI, and may be doped with a second conductive dopant. For example, the second conductivity type semiconductor layer 156 may be a semiconductor material having a composition formula of In _x Al _y Ga _{1 -x- y} N (0? X? 1, 0? _Y? 1, 0? _X + y? Or AlInN, AlGaAs, GaP, GaAs, GaAsP, and AlGaInP. When the second conductivity type semiconductor layer 156 is a p-type semiconductor layer, the second conductivity type dopant may be a p-type dopant such as Mg, Zn, Ca, Sr, and Ba. The second conductivity type semiconductor layer 156 may have a single layer or a multi-layer structure, but the present invention is not limited thereto. If the light emitting device 100A illustrated in FIG. 3A is ultraviolet (UV), deep UV, or unpolarized light emitting device, the second conductivity type semiconductor layer 156 may include at least one of InAlGaN and AlGaN can do.

On the other hand, the first and second electrode layers 142 and 144 are disposed under the first and second conductivity type semiconductor layers 152 and 156, respectively. The first electrode layer 142 is in contact with the first conductivity type semiconductor layer 152 and the second electrode layer 144 is in contact with the second conductivity type semiconductor layer 154. The first and second electrode layers 142 and 144, Each may be implemented as a metal. For example, each of the first and second electrode layers 142 and 144 may be formed of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, .

In addition, each of the first and second electrode layers 142 and 144 may be a transparent conductive oxide (TCO). For example, each of the first and second electrode layers 142 and 144 may include at least one of the above-described metal material, indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO) IGTO (indium gallium tin oxide), AZO (aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc oxide), IrOx, RuOx, RuOx / ITO, Ni / IrOx / Au, and Ni / IrOx / Au / ITO, and the material is not limited thereto. The first and second electrode layers 142 and 144 may include a material that makes ohmic contact with the first and second conductivity type semiconductor layers 152 and 156, respectively.

Further, each of the first and second electrode layers 142 and 144 may be formed as a single layer or multiple layers of a reflective electrode material having an ohmic characteristic. If the first and second electrode layers 142 and 144 each function as an ohmic layer, a separate ohmic layer (not shown) may not be disposed.

The first and second electrode layers 142 and 144 of the light emitting device 100A illustrated in FIG. 3A are positioned on the submount 110A in a flip manner. The first electrode layer 142 is connected to the first electrode pad 122 on the submount 110A through the first bump 132 and the second electrode layer 144 is connected to the submount 110B through the second bump 134. [ And is connected to the second electrode pad 124 on the mount 110A.

The submount 110A may be made of a semiconductor substrate such as AlN, BN, SiC, GaN, GaAs, Si, or the like, but may be made of a semiconductor material having thermal properties without being limited thereto.

In addition, the sub-mount 110A can be divided into a first area A1 and a second area A21 and A22. The light emitting structure 150 is mounted on the first region A1 of the submount 110A and the second regions A21 and A22 are adjacent to the first region A1.

If the submount 110A is made of Si, a protective layer (not shown) made of an insulating material may be further disposed between the first and second electrode pads 122 and 124 and the submount 110A.

The first and second electrode pads 122 and 124 are disposed on the submount 110A so as to be spaced apart from each other across the first and second regions A1, A21, and A22. At this time, the distance L between the tip of the first and second electrode pads 122 and 124 and the edge of the submount 110A may be greater than or equal to '0'.

At least one of the first and second electrode pads 122 and 124 includes the inclined top surfaces 122-1 and 124-1 in the second regions A21 and A22 of the submount 110A. The upper surfaces 122-1 and 124-1 serve to reflect the light 180 and 182 emitted from the sides of the light emitting structure 150 in the upward direction to improve the light extraction efficiency of the light emitting device 100A .

In order to reflect light, each of the first and second electrode pads 122 and 124 may include a metallic material, and the reflectance of each pad 122 and 124 may have various values depending on the characteristics of the metallic material . For example, each of the first and second electrode pads 122 and 124 may include at least one of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, , And the like. Alternatively, each of the first and second electrode pads 122 and 124 may be formed of a metal or an alloy and a transparent conductive material such as ITO, IZO, IZTO, IAZO, IGZO, IGTO, AZO, ATO, Specifically, it can be laminated with IZO / Ni, AZO / Ag, IZO / Ag / Ni, AZO / Ag / Ni, Ag / Cu, Ag / Pd /

3a embodiment In the illustrated embodiment, the first electrode pad 122 includes not only the inclined top surface 122-1 in the second area A21 of the submount 110A, but also the second electrode pad 124 Also includes an inclined top surface 124-1 in the second area A22 of the submount 110A. However, according to another embodiment, only one of the first and second electrode pads 122, 124 may include the inclined top surfaces 122-1, 124-1.

Hereinafter, the light emitting device 100A will be described based on the configuration of the first and second electrode pads 122 and 124 as illustrated in FIG. 3A, but only one of the first and second electrode pads 122 and 124 Obviously, the following description can be applied to the inclusion of the inclined upper surfaces 122-1 and 124-1.

According to the embodiment, the first electrode pad 122 includes first and second segments 122A and 122B. The first segment 122A is disposed in the first region A1 of the submount 110A and is connected to the first electrode layer 142 through the first bump 132. [ The second segment 122B extends obliquely from the first segment 122A by an inclination angle? 1 and is disposed in the second area A21 of the submount 110A and has a sloped top surface 122-1. Similarly, the second electrode pad 124 includes first and second segments 124A and 124B. The first segment 124A is disposed in the first area A1 of the submount 110A and is connected to the second electrode layer 144 through the second bump 134. [ The second segment 124B extends obliquely from the first segment 124A by an angle of inclination? 2 and is disposed in the second area A22 of the submount 110A and has an inclined upper surface 124-1.

The inclination angle? 1 of the upper surface 122-1 of the first electrode pad 122 and the inclination angle? 2 of the upper surface 124-1 of the second electrode pad 124 may be different or equal to each other have. If the inclination angles? 1 and? 2 are too large, the light reflected from the upper surfaces 122-1 and 124-1 after being emitted from the side of the light emitting structure 150 can be incident on the light emitting structure 150 again have. In this case, even if the inclined upper surfaces 122-1 and 124-1 reflect light, a high light extraction efficiency can not be expected. If the inclination angles? 1 and? 2 are too small, light emitted from the side of the light emitting structure 150 may not be smoothly reflected in the upward direction. Therefore, the inclination angles? 1 and? 2 of the upper surfaces 122-1 and 124-1 may be 10 ° to 50 °, for example, 30 °.

When the height H of the submount 110A on which the second segments 122B and 124B are arranged in the second regions A21 and A22 illustrated in Fig. 3A is too low, the second segments 122B and 124B It may be difficult to reflect a large amount of light. Also, if the height H is too high, the light reflected at the second segment 122B, 124B may be re-incident to the light emitting structure 150. [ Therefore, the height H may be 300 * tan? To 500 * tan? Nm, for example 400 * tan? Nm. Here,? Can be? 1 or? 2.

In addition, the submount 110A illustrated in FIG. 3A has a flat top surface 110-1 in the first region A1 and has a sloping top surface 110-2 in each of the second regions A21 and A22, 110-3. At this time, the thickness T1 of the first electrode pad 122 in the first region A1 may be the same as the thickness T2 of the second region A21. That is, the first electrode pad 122 may have a uniform thickness in the first and second regions A1 and A21. Similarly, the thickness T1 in the first region A1 of the second electrode pad 124 may be equal to the thickness T2 in the second region A22. That is, the second electrode pad 124 may have a uniform thickness in both the first and second regions A1 and A22.

According to another embodiment, the submount 110B illustrated in Fig. 3B has a flat top surface 110-1 in both the first area A1 and the second area A21, A22. However, unlike the light emitting device 100A illustrated in FIG. 3B, the thickness T1 of the first segment 122C of the first electrode pad 122 in the first region A1 is uniform, The thickness of the second segment 122D of the first electrode pad 122 in the first electrode pad A21 increases toward the edge of the outer edge to form the inclination angle [theta] 1. That is, the thickness of the first segment 122D increases from T21 to T22 from the boundary between the first region A1 and the second region A21 to the edge of the first electrode pad 122. Similarly, in the first region A1, the thickness T1 of the first segment 124C of the second electrode pad 124 is uniform, while the thickness T1 of the second electrode pad 124 in the second region A22 is uniform, The thickness of the two segments 124D increases toward the edge of the outer edge to form the inclination angle [theta] 2. That is, from the boundary between the first area A1 and the second area A22 to the edge of the second segment 124D, the thickness of the second segment 124D increases from T21 to T22. Here, if the inclination angles? 1 and? 2 are different from each other, the maximum thickness T22 of the first and second electrode pads 122 and 124 may be different from each other. Except for this, the light emitting device 100B illustrated in FIG. 3B is the same as the light emitting device 100A illustrated in FIG. 3A, and thus the same reference numerals are used, and a detailed description thereof will be omitted.

A first upper bump metal layer (not shown) is further disposed between the first electrode layer 142 and the first bump 132 and a second upper bump metal layer (not shown) is disposed between the first electrode pad 142 and the first bump 132 And a first bump metal layer (not shown) may be further disposed between the first bump 132 and the first bump 132. Here, the first upper bump metal layer and the first lower bump metal layer serve to indicate a position where the first bump 132 is located. Similarly, a second upper bump metal layer (not shown) is further disposed between the second electrode layer 144 and the second bump 134, and the first segment 124A of the second electrode pad 124 and the second bump metal layer 134 may be further disposed between the first and second lower bump metal layers (not shown). Here, the second upper bump metal layer and the second lower bump metal layer serve to indicate a position where the second bump 134 is located.

The above-described first and second electrode pads 122 and 124 and the submount 110A are merely examples for facilitating understanding of the embodiment, and the present embodiment is not limited to this structure.

The inclined upper surfaces 122-1 and 124-1 of at least one of the first and second electrode pads 122 and 124 in the light emitting devices 100A and 100B illustrated in FIGS. It may have a light reflection pattern so that light emitted from the side of the light guide plate 150 is more reflected.

The upper surface inclined in the second region A21 of the first electrode pad 122 in the light emitting devices 100C and 100D illustrated in Figures 3C and 3D has a light reflection pattern 122-2, The top surface of the slope in the second region A22 of the pad 124 is illustrated as having a light reflection pattern 124-2. Except for this, the light emitting devices 100C and 100D illustrated in FIGS. 3C and 3D are the same as those of the light emitting devices 100A and 100B illustrated in FIGS. 3A and 3B, and thus the same reference numerals are used, . The light reflection patterns 122-2 and 124-2 illustrated in Figs. 3C and 3D can cause the light 180,182 emitted from the side of the light emitting structure 150 to diffuse more evenly, Therefore, the light extraction efficiency can be further improved.

In the light emitting devices 100C and 100D illustrated in Figs. 3C and 3D, only the second segments 122B and 124B in the first and second electrode pads 122 and 124 are formed in the light reflection patterns 122-2 and 124 2, but it should be understood that the top surface of the first segment 122A, 124A may also have a light reflection pattern, such as the second segment 122B, 124B, although not shown .

Although the light reflection patterns 122-2 and 124-2 in the light emitting devices 100C and 100D illustrated in Figs. 3C and 3D are convex hemispherical cross-sectional shapes, the embodiments are not limited thereto. Hereinafter, the light reflection pattern of the embodiment may have various forms as follows.

4A to 4I are perspective views of light reflection patterns 220A to 220I according to the embodiment. Here, the light reflection patterns 220A to 220I correspond to the embodiments of the light reflection patterns 122-2 and 124-2 illustrated in FIGS. 3C and 3D, and are formed integrally with the base layer 210. FIG. The base layer 210 may correspond to at least one of the first and second segments 122A, 122B, 122C and 122D of the first electrode pad 122 and may correspond to at least one of the first and second segments 122A, And may correspond to at least one of the two segments 124A, 124B, 124C, and 124D.

According to the embodiment, the light reflection pattern may be a hemispherical shape 220A as illustrated in FIG. 4A, a prism shape 220B as illustrated in FIG. 4B, May be a cone shape 220C as shown, a truncated shape 220D as illustrated in FIG. 4D, a cylindrical shape 220E as illustrated in FIG. 4E, And may be in the form of a hexahedron 220F as illustrated in FIG. 4f, but may be of various shapes without limitation.

In addition, the light reflection pattern may be in the form of a bar. For example, the light reflection pattern illustrated in FIG. 4G may be a secondary prism bar shape 220G, and may be a bar shape having various shapes such as a hexahedral bar shape and a bent bar shape.

Further, the light reflection pattern may have a lattice form. For example, the light reflection pattern illustrated in FIG. 4H may be a secondary prism lattice pattern 220H, and may be in the form of a lattice of various shapes such as a hexagonal lattice pattern, a truncated lattice pattern, and the like.

In addition, although the light reflection patterns 220A to 220H illustrated in Figs. 4A to 4H described above are in the relief shape, the light reflection pattern may be in the relief shape. For example, as illustrated in FIG. 4I, the light reflection pattern may be a cylinder intaglio shape 220I.

4A, 4B and 4E to 4I, the light reflection patterns may be periodically spaced apart from each other at regular intervals, but may be spaced apart from each other at irregular intervals as illustrated in FIG. 4C or 4D, It may also show a periodic appearance.

In addition, although not shown, the light reflection pattern may include a hemispherical shape 220A, a secondary prism shape 220B, a cone shape 220C, a trapezoidal shape (see FIG. 4A) truncated shape 220D, cylindrical shape 220E, and hexahedral shape 220F.

The light emitting devices 100A to 100D illustrated in FIGS. 3A to 3D are disposed at the positions of the first and second bumps 132 and 134 in the light emitting device 100 illustrated in FIG. 2, The present invention is not limited to the shapes of the first and second electrode pads 122 and 124 and the first and second bumps 132 and 134 may be variously positioned and the first and second electrode pads 122 and 124 may have various plan shapes. Of course, can be applied.

Hereinafter, a manufacturing method according to an embodiment of the light emitting devices 100A to 100D illustrated in FIGS. 3A to 3D will be described as follows. These light emitting devices 100A to 100D are not limited to the manufacturing method shown in Figs. 5A to 7B and may be manufactured by various other manufacturing methods.

5A to 5C are cross-sectional views illustrating a method of manufacturing the upper structures 142, 144, 150, 160, and 170 of the light emitting devices 100A to 100D according to the embodiment.

Referring to FIG. 5A, a buffer layer 160 is formed on a substrate 170.

The substrate 170 may be formed of at least one of sapphire (Al ₂ O ₃ ), SiC, GaAs, GaN, ZnO, Si, GaP, InP and Ge. The present invention is not limited thereto.

In addition, the buffer layer 160 may be formed of a light-transmitting material, for example, but not limited to, AlN or an undoped nitride. The buffer layer 160 may be omitted depending on the type of the substrate 170 and the type of the light emitting structure 150.

The light emitting structure 150 is grown on the buffer layer 160. The light emitting structure 150 may be formed by successively growing a first conductive semiconductor layer 152, an active layer 154, and a second conductive semiconductor layer 156 on the buffer layer 160. The light emitting structure 150 may be formed using a metal organic chemical vapor deposition (MOCVD) method, a chemical vapor deposition (CVD) method, a plasma enhanced chemical vapor deposition (PECVD) method, (MBE), hydride vapor phase epitaxy (HVPE), or the like, but the present invention is not limited thereto.

The first conductive semiconductor layer 152 may be formed of a light-transmitting material, and may be formed of Al _x In _y Ga _(1-xy) N (0 x 1, 0 y 1, 0 x + 1), InAlGaN, AlGaAs, GaP, GaAs, GaAsP, and AlGaInP. When the first conductive semiconductor layer 152 is an n-type semiconductor layer, the first conductive dopant may include n-type dopants such as Si, Ge, Sn, Se, and Te. The first conductive semiconductor layer 152 may be formed as a single layer or a multilayer, but the present invention is not limited thereto. If the light emitting devices 100A to 100D illustrated in FIGS. 3A to 3D are ultraviolet (UV), deep UV, or unpolarized light emitting devices, the first conductivity type semiconductor layer 152 may be formed of InAlGaN and AlGaN As shown in FIG.

The active layer 154 may be formed of any one of a double heterostructure, a multi-well structure, a single quantum well structure, a multi quantum well (MQW) structure, a quantum dot structure, or a quantum wire structure. The active layer 154 may include a well layer and a barrier layer such as InGaN / GaN, InGaN / InGaN, GaN / AlGaN, InAlGaN / GaN, GaAs (InGaAs), / AlGaAs, GaP (InGaP) / AlGaP, but the present invention is not limited thereto. The well layer may be formed of a material having an energy band gap smaller than the energy band gap of the barrier layer. In particular, the active layer 154 according to the embodiment can generate ultraviolet or deep ultraviolet light.

The second conductive semiconductor layer 156 may be formed on the active layer 154. The second conductivity type semiconductor layer 156 may be formed of a semiconductor compound. The second conductive semiconductor layer 156 may be formed of a compound semiconductor such as a group III-V or a group II-VI, and may be doped with a second conductive dopant. For example, a semiconductor material having a composition formula of In _x Al _y Ga _{1 -x- y} N (0? X? 1, 0? _Y? 1, 0? _X + y? 1) or AlInN, AlGaAs, GaP, GaAs, GaAsP , AlGaInP, or the like. When the second conductivity type semiconductor layer 156 is a p-type semiconductor layer, the second conductivity type dopant may be a p-type dopant such as Mg, Zn, Ca, Sr, and Ba. The second conductivity type semiconductor layer 156 may be formed as a single layer or a multilayer, but is not limited thereto. If the light emitting devices 100A to 100D illustrated in FIGS. 3A to 3D are ultraviolet (UV), deep UV, or unpolarized light emitting devices, the second conductivity type semiconductor layer 156 may be formed of InAlGaN and AlGaN As shown in FIG.

5B, mesa etching is performed on the first conductivity type semiconductor layer 152, the active layer 154 and the second conductivity type semiconductor layer 156 to form the first conductivity type semiconductor layer 152, Lt; / RTI >

Referring to FIG. 5C, first and second electrode layers 142 and 144 are formed on the exposed portions of the first conductive semiconductor layer 152 and the second conductive semiconductor layer 156, respectively. Each of the first and second electrode layers 142 and 144 may be formed of a metal such as Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, May be formed by an optional combination.

In addition, each of the first and second electrode layers 142 and 144 may be a transparent conductive oxide film (TCO). For example, each of the first and second electrode layers 142 and 144 may include at least one of the above-described metal material, indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO) IGTO (indium gallium tin oxide), AZO (aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc oxide), IrOx, RuOx, RuOx / ITO, Ni / IrOx / Au, and Ni / IrOx / Au / ITO, and the material is not limited thereto.

6A to 6C are process cross-sectional views for explaining a manufacturing method according to an embodiment of the lower structures 122, 124, and 110A of the light emitting devices 100A and 100C illustrated in FIGS. 3A and 3C.

The manufacturing method shown in Figs. 6A to 6C may be performed in a separate process during the processes shown in Figs. 5A to 5C.

Referring to FIG. 6A, a submount 110 is prepared. For example, the submount 110A may be formed of AlN, BN, silicon carbide (SiC), GaN, GaAs, Si, or the like, and may be formed of a semiconductor material having thermal properties without being limited thereto.

Next, referring to FIG. 6B, the submount 110 is patterned in a parabolic shape with a recess 112. FIG. Here, inclined recesses 112 are formed so as to be flat in the first region A1 and have inclination angles? 1 and? 2 in the second regions A21 and A22.

Referring to FIG. 6C, first and second electrode pads 122 and 124 are formed on the submount 110A on which the recess 112 is formed. Even if the first and second electrode pads 122 and 124 are formed to have the same thickness in the first and second regions A1 and A22, the submount 110A is inclined in the second regions A21 and A22 The upper surfaces of the second segments 122B and 124B of the first and second electrode pads 122 and 124 are inclined at inclination angles? 1 and? 2.

Each of the first and second electrode pads 122 and 124 may be formed of a metallic material, and the reflectance may have various values depending on the characteristics of the metallic material. For example, each of the first and second electrode pads 122 and 124 may include at least one of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, , And the like. Alternatively, each of the first and second electrode pads 122 and 124 may be formed of a metal or an alloy and a transparent conductive material such as ITO, IZO, IZTO, IAZO, IGZO, IGTO, AZO, ATO, Specifically, it can be formed in a laminated form of IZO / Ni, AZO / Ag, IZO / Ag / Ni, AZO / Ag / Ni, Ag / Cu, Ag / Pd /

If the submount 110A is made of Si, a protective layer (not shown) may be further formed on the submount 110A before the first and second electrode pads 122 and 124 are formed . In this case, after the protective layer is formed, first and second electrode pads 122 and 124 are formed on the protective layer.

Thereafter, after the lapping and polishing process is performed on the resultant shown in FIG. 5C, the substrate 170 is rotated so as to be arranged on the top side, and then combined with the resultant shown in FIG. 6C, Thereby completing the light emitting device 100B. At this time, the first electrode layer 142 and the first segment 122A of the first electrode pad 122 are coupled by the first bump 132 and the second segment 122A of the first electrode pad 122 is coupled by the second bump 134 The second electrode layer 144 and the first segment 124A of the second electrode pad 124 are coupled.

Further, in the result shown in Fig. 6C, after the upper surface of the second segment 122B, 124B is patterned to have a light reflection pattern as illustrated in Fig. 3C, the patterned result is combined with the output illustrated in Fig. 5C The light emitting device 100C illustrated in FIG. 3C may be completed.

FIGS. 7A and 7B are process cross-sectional views illustrating a method of manufacturing the lower structures 110B, 122, and 124 of the light emitting devices 100B and 100D illustrated in FIGS. 3B and 3D.

As shown in Fig. 6A, the submount 110 is prepared. When the light emitting device 100B illustrated in FIG. 3B is manufactured, a sub-mount 110 that is thinner than the light emitting device 100A illustrated in FIG. 3A is prepared. This is because it is not necessary to pattern the submount 110 as shown in FIG. 6B when manufacturing the light emitting device 100B illustrated in FIG. 3B. Thus, the submount 110 of FIG. 6A corresponds to the submount 110B of FIG. 3B.

Next, referring to FIG. 7A, an electrode pad layer 120 is formed on the submount 110B. The electrode pad layer 120 may be formed of the same material as the first and second electrode pads 122 and 124.

Referring to FIG. 7B, the electrode pad layer 120 is patterned so that the second segments 122B and 124B of the first and second electrode pads 122 and 124 are inclined at angles? 1 and? 2, A recess 126 is formed so as to have a surface. Here, the method of forming the recess 126 differs depending on the kind of material constituting the electrode pad layer 120. The recesses 126 may be formed using metal patterning techniques, which are self-evident at the level of those skilled in the art and will not be described in detail herein.

Next, after performing the lapping and polishing process on the resultant shown in FIG. 5C, the substrate 170 is rotated so as to be arranged on the top side, and then combined with the resultant shown in FIG. 7B to form the light emitting device 100B illustrated in FIG. . At this time, the first electrode layer 142 and the first segment 122C of the first electrode pad 122 are coupled by the first bump 132, and the second electrode layer 144 and the second electrode layer 142 are bonded together by the second bump 134, And the second segment 122D of the second electrode pad 124 is coupled.

Also, in the result shown in FIG. 7B, the upper surface of the second segment 122D, 124D is patterned to have a light reflection pattern as illustrated in FIG. 3D, and the patterned result is combined with the output illustrated in FIG. 5C The light emitting device 100D illustrated in Fig. 3D can be completed.

In the light emitting devices 100A to 100D illustrated in FIGS. 3A to 3D, the refractive index n ₁₇₀ of the substrate 170, the refractive index n ₁₆₀ of the buffer layer 160, The light emitted from the active layer 154 can be smoothly emitted in the upward direction and the light extraction efficiency can be increased when the refractive indexes n ₁₅₂ and n _{156 of the} respective layers ₁₅₂ and ₁₅₆ have the relationship represented by the following Equation 1 .

However, when the light emitting devices 100A to 100D illustrated in FIGS. 3A to 3D are ultraviolet light, deep ultraviolet light, or unpolarized light emitting device, the substrate 170, the buffer layer 160, the first and second conductive semiconductor layers 152, and 156 have the relationship as shown in the following equation (2).

That is, in the ultraviolet light, the deep ultraviolet light or the non-polarized light emitting device, the first conductivity type semiconductor layer 152 may be implemented as AlGaN and the second conductivity type semiconductor layer 156 may be implemented as GaN. If the substrate 170 is implemented with sapphire and the buffer layer 160 is implemented with AlN, the refractive indices of the substrate 170, the buffer layer 160, and the first and second conductivity type semiconductor layers 152, &Quot; (2) " The refractive index (n ₁₅₆ = 2.44) of GaN as the second conductive type semiconductor layer 156 is larger than the refractive index (n ₁₅₂ = 2.28) of Al _{0 .5} GaN which is the first conductive type semiconductor layer 152, the refractive index of AlN ₍₁₆₀ n = 2.12) is a substrate 170, a refractive index of sapphire (n = 1.36 ₁₇₀₎ greater than the first conductive type semiconductor layer 152, the refractive index of the _{Al 0 .5 GaN (n 152 =} 2.28 Is larger than the refractive index (n ₁₆₀ = 2.12) of AlN which is the buffer layer 160.

As described above, if the refractive index decreases toward the upper direction, the light emitted from the active layer 154 may travel in the lateral direction of the light emitting structure 150, thereby deteriorating the light extraction efficiency. However, according to the embodiment, even when the refractive index between the respective layers 156, 152, 160, and 170 in the light emitting structure 150 has the relationship expressed by Equation (2), the first and second electrode pads 122 The light extraction efficiency can be improved because the presence of at least one of the inclined upper surfaces 122-1, 122-2, 124-1, 124-2 of the light receiving surfaces 124 have.

Hereinafter, an embodiment of the light emitting device package 200 including the above-described light emitting devices 100A to 100D will be described as follows.

8 is a cross-sectional view of a light emitting device package 200 according to an embodiment.

A light emitting device package 200 according to an embodiment includes a light emitting device 100A, a header 210, a bonding portion 220, a pair of lead wires 232 and 234, a pair of wires 242 and 244, A side wall portion 250, and a molding member 260. The light emitting device 100A corresponds to the light emitting device illustrated in FIG. 3A, but the following description can be applied equally to any of the light emitting devices 100B, 100C, and 100D illustrated in FIGS. 3B to 3D. The same reference numerals as those in FIG. 3A are used for the light emitting device 100A, and redundant explanations are omitted here.

The submount 110A is bonded to the header 210 by a bonding portion 220. [ The bonding portion 220 may be in the form of solder or paste. The first electrode pad 122 of the light emitting device 100A is connected to the lead wire 232 through the wire 242 and the second electrode pad 124 is connected to the lead wire 234 through the wire 244. [ Power is supplied to the light emitting device 100A through a pair of lead wires 232 and 234 which are electrically separated from each other.

The molding member 260 is filled in the cavity of the package 200 formed by the side wall part 250 so as to surround and protect the light emitting device 100A. In addition, the molding member 260 may include a phosphor to change the wavelength of light emitted from the light emitting device 100A.

A plurality of light emitting device packages according to other embodiments may be arranged on a substrate, and a light guide plate, a prism sheet, a diffusion sheet, a fluorescent sheet, or the like may be disposed on a path of light emitted from the light emitting device package. The light emitting device package, the substrate, and the optical member may function as a backlight unit or function as a lighting unit. For example, the lighting system may include a backlight unit, a lighting unit, a pointing device, a lamp, and a streetlight.

9 is a perspective view of a lighting unit 300 according to an embodiment. However, the illumination unit 300 of Fig. 9 is an example of the illumination system, but is not limited thereto.

The illumination unit 300 includes a case body 310, a connection terminal 320 installed in the case body 310 and supplied with power from an external power source, a light emitting module unit 330 installed in the case body 310, ).

The case body 310 is formed of a material having a good heat dissipation property, and may be formed of metal or resin.

The light emitting module unit 330 may include a substrate 332 and at least one light emitting device package 200 mounted on the substrate 332.

The substrate 332 may be a printed circuit pattern on an insulator and may be a printed circuit board (PCB), a metal core PCB, a flexible PCB, a ceramic PCB, or the like .

In addition, the substrate 332 may be formed of a material that efficiently reflects light, or may be formed of a color whose surface is efficiently reflected, for example, white, silver, or the like.

At least one light emitting device package 200 may be mounted on the substrate 332. Each of the light emitting device packages 200 may include at least one light emitting device 100A to 100D, for example, a light emitting diode (LED). The light emitting diode may include a colored light emitting diode that emits red, green, blue, or white colored light, and a UV light emitting diode that emits ultraviolet (UV) light.

The light emitting module unit 330 may be arranged to have a combination of various light emitting device packages 200 to obtain colors and brightness. For example, a white light emitting diode, a red light emitting diode, and a green light emitting diode may be arranged in combination in order to secure a high color rendering index (CRI).

The connection terminal 320 may be electrically connected to the light emitting module unit 330 to supply power. In the embodiment, the connection terminal 320 is connected to the external power source by being inserted in a socket manner, but the present invention is not limited thereto. For example, the connection terminal 320 may be formed in a pin shape and inserted into an external power source, or may be connected to an external power source through wiring.

10 is an exploded perspective view of the backlight unit 400 according to the embodiment. However, the backlight unit 400 of FIG. 10 is an example of the illumination system, and the present invention is not limited thereto.

The backlight unit 400 includes a light guide plate 410, a reflective member 420 under the light guide plate 410, a bottom cover 430, a light emitting module unit 440 for providing light to the light guide plate 410 ). The bottom cover 430 houses the light guide plate 410, the reflection member 420, and the light emitting module unit 440.

The light guide plate 410 serves to diffuse light to make a surface light source. The light guide plate 410 is made of a transparent material, and may be made of, for example, acrylic resin such as PMMA (polymethyl methacrylate), polyethylene terephthalate (PET), polycarbonate (PC), cycloolefin copolymer (COC), and polyethylene naphthalate As shown in FIG.

The light emitting module unit 440 provides light to at least one side of the light guide plate 410, and ultimately acts as a light source of the display device in which the backlight unit is installed.

The light emitting module 440 may be in contact with the light guide plate 410, but is not limited thereto. Specifically, the light emitting module unit 440 includes a substrate 442 and a plurality of light emitting device packages 200 mounted on the substrate 442. The substrate 442 may be in contact with the light guide plate 410, but is not limited thereto.

The substrate 442 may be a PCB including a circuit pattern (not shown). However, the substrate 442 may include not only general PCB but also metal core PCB (MCPCB), flexible PCB, and the like, but the present invention is not limited thereto.

The plurality of light emitting device packages 200 may be mounted on the substrate 442 such that the light emitting surface on which the light is emitted is spaced apart from the light guiding plate 410 by a predetermined distance.

A reflective member 420 may be formed under the light guide plate 410. The reflective member 420 reflects the light incident on the lower surface of the light guide plate 410 so as to face upward, thereby improving the brightness of the backlight unit. The reflective member 420 may be formed of, for example, PET, PC, PVC resin or the like, but is not limited thereto.

The bottom cover 430 may house the light guide plate 410, the light emitting module 440, the reflective member 420, and the like. To this end, the bottom cover 430 may be formed in a box shape having an opened top surface, but the present invention is not limited thereto.

The bottom cover 430 may be formed of a metal or a resin, and may be manufactured using a process such as press molding or extrusion molding.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

100A, 100B, 100C, 100D:
110, 110A, 110B: Sub mount 112, 126:
120: electrode pad layer 122, 124: electrode pad
132, 134: bumps 142, 144: electrode layer
150: light emitting structure 152: first conductivity type semiconductor layer
154: active layer 156: second conductivity type semiconductor layer
160: buffer layer 170: substrate
200: light emitting device package 210: header
220: adhesive section 232, 234: lead wire
242, 244: wire 250:
260: molding member 300: illuminating unit
310: Case body 320: Connection terminal
330, 440: light emitting module part 400: back light unit
410: light guide plate 420: reflective member
430: bottom cover

Claims (13)

Board;
A light emitting structure having a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer disposed under the substrate;
First and second electrode layers disposed under the first and second conductive type semiconductor layers, respectively;
A submount having a first region in which the light emitting structure is mounted and a second region adjacent to the first region; And
And first and second electrode pads spaced from each other on the submount and electrically connected to the first and second electrode layers, respectively,
At least one of the first and second electrode pads
An upper surface having an inclined shape in the second region of the submount and reflecting light of the light emitting structure;
A first segment disposed in the first region of the submount; And
And a second segment extending obliquely from the first segment and disposed in the second region of the submount and having the inclined upper surface,
Wherein a refractive index of the second conductivity type semiconductor layer is greater than a refractive index of the first conductivity type semiconductor layer, and a refractive index of the first conductivity type semiconductor layer is greater than a refractive index of the substrate. delete 2. The apparatus of claim 1, wherein the submount has a flat top surface in the first area, an inclined top surface in the second area,
Wherein at least one of the first and second electrode pads has a uniform thickness in the first and second regions. 2. The apparatus of claim 1, wherein the submount has a flat upper surface in the first and second areas,
At least one of the first and second electrode pads
The first region having a uniform thickness,
Wherein the light emitting device has a thickness that increases toward the edge to form the inclined upper surface in the second region. The light emitting device according to claim 1, wherein the first electrode pad and the second electrode pad have the same inclination angle. The light emitting device according to claim 1, wherein the first electrode pad and the second electrode pad have different inclination angles from each other. The light emitting device according to any one of claims 1, 5 and 6, wherein the top surface has an inclination angle of 10 to 50 degrees. The light emitting device according to claim 1 or 5, wherein the top surface has an inclination angle of 30 °. The light emitting device according to any one of claims 1, 5 and 6, wherein the inclined height of the upper surface is 300 * tan? To 500 * tan? Nm (where? Is the inclination angle of the upper surface). The light emitting device according to claim 1, wherein the upper surface of at least one of the first and second electrode pads has a light reflection pattern for reflecting light from the light emitting structure,
Wherein the light reflection pattern is at least one of a hemisphere, a secondary prism, a cone, a truncated, a cylindrical, a hexahedron, a bar, and a lattice pattern. The light emitting device according to claim 1, further comprising a buffer layer disposed between the substrate and the light emitting structure,
Wherein the refractive index of the buffer layer is larger than the refractive index of the substrate, and the refractive index of the first conductivity type semiconductor layer is larger than the refractive index of the buffer layer. delete delete

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