KR20160066319A - Light Emitting Device Package - Google Patents

Abstract

An embodiment includes a substrate having a first electrode and a second electrode; A light emitting structure including a first conductivity type semiconductor layer, an active layer and a second conductivity type semiconductor layer; and a first electrode pad provided on the first conductivity type semiconductor layer and the second conductivity type semiconductor layer, And a second electrode pad and is flip-bonded on the substrate, wherein the light-transmitting substrate has a sloped surface formed on a surface opposite to the light-emitting structure.

Description

[0001] Light Emitting Device Package [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device package, and more particularly, to a light emitting device package capable of controlling a pattern of light emitted from a light emitting device by an inclined surface formed on a substrate of the light emitting device.

BACKGROUND ART Light emitting devices such as a light emitting diode (LD) or a laser diode using semiconductor materials of Group 3-5 or 2-6 group semiconductors are widely used for various colors such as red, green, blue, and ultraviolet And it is possible to realize white light rays with high efficiency by using fluorescent materials or colors, and it is possible to realize low energy consumption, semi-permanent life time, quick response speed, safety and environment friendliness compared to conventional light sources such as fluorescent lamps and incandescent lamps .

Therefore, a transmission module of the optical communication means, a light emitting diode backlight replacing a cold cathode fluorescent lamp (CCFL) constituting a backlight of an LCD (Liquid Crystal Display) display device, a white light emitting element capable of replacing a fluorescent lamp or an incandescent lamp Diode lighting, automotive headlights, and traffic lights.

In the light emitting device, electrons injected through the first conductive type semiconductor layer and holes injected through the second conductive type semiconductor layer meet each other to emit light having energy determined by a specific energy band of the material forming the active layer (light emitting layer) do. In the light emitting device package, the phosphor is excited by the light emitted from the light emitting device to emit light in a longer wavelength range than the light emitted from the active layer.

1 is a view showing a conventional light emitting device package.

1, a conventional light emitting device package 10 includes a light emitting device 14 coupled to a substrate 11 through a bonding layer 13, a pair of lead frames ) 12a and 12b are arranged.

The wire 15 is bonded to the first and second lead frames 12a and 12b and the power is supplied to the light emitting element 14. A molding part 16 is provided to surround the light emitting element 14 and the wire 15 to protect the light emitting element 14 and the wire 15. The molding portion 16 includes the phosphor 17. [

The light emitted from the light emitting element 14 of the conventional light emitting device package 10 as described above is emitted to the front side. However, in order to emit light to the side, a lens or a diffuser for changing the light path must additionally be provided in the light emitting device package, which increases the size of the light emitting device package, .

SUMMARY OF THE INVENTION An embodiment of the present invention provides a light emitting device package having an inclined surface on a substrate of a light emitting device and controlling a path of light emitted from the light emitting device.

According to an aspect of the present invention, there is provided a plasma display panel comprising: a substrate having a first electrode and a second electrode; A light emitting structure including a first conductivity type semiconductor layer, an active layer and a second conductivity type semiconductor layer; and a first electrode pad provided on the first conductivity type semiconductor layer and the second conductivity type semiconductor layer, And a second electrode pad and is flip-bonded on the substrate, wherein the light-transmitting substrate has a sloped surface formed on a surface opposite to the light-emitting structure.

In an embodiment, the substrate may be a thermally conductive substrate.

The transparent substrate may be sapphire.

The inclined surface may be inclined at 45 to 60 degrees with respect to the surface of the light emitting structure.

The light-transmitting substrate may further include a phosphor layer disposed on a surface of the light-transmitting substrate, and the phosphor layer may conformally coat the surface of the light-transmitting substrate.

In addition, the phosphor layer may be disposed on the inclined surface and the side surface of the transparent substrate.

The first electrode pad may be disposed on a part of the first conductive semiconductor layer exposed by mesa etching, and the second electrode pad may be disposed on one side of the lower surface of the second conductive semiconductor layer .

The first and second electrode pads of the light emitting device may be soldered to the first electrode and the second electrode of the substrate, respectively.

According to the above-described embodiment, the substrate of the light emitting device is provided with the inclined surface, and a side emitting light pattern can be obtained by guiding the light emitted from the light emitting device to the side.

In order to obtain a site-emitting light pattern, a chip size package (CSP) is formed by attaching the light emitting device directly to the substrate of the light emitting device package without providing a lens or a diffuser, ) Can be implemented.

In addition, the manufacturing cost of the light emitting device package can be reduced by simplifying the manufacturing process of the light emitting device package.

1 is a view showing a conventional light emitting device package.
2 is a view illustrating a light emitting device package according to the first embodiment.
3 is a view illustrating a light emitting device package according to a second embodiment.
4A to 4D illustrate a process of the light emitting device package according to the first embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

In the description of embodiments according to the present invention, in the case of being described as being formed "on or under" of each element, the upper (upper) or lower (lower) or under are all such that two elements are in direct contact with each other or one or more other elements are indirectly formed between the two elements. Also, when expressed as "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.

FIG. 2 is a view illustrating a light emitting device package according to a first embodiment, and FIG. 3 is a view illustrating a light emitting device package according to a second embodiment.

2 and 3, the light emitting device package 100 according to the present embodiment includes a substrate 120 having a first electrode 120a and a second electrode 120b, a light transmitting substrate 144, And a light emitting device 140 including a light emitting structure 148 in which a semiconductor compound of a semiconductor layer is stacked and flip-bonded on the substrate 120.

In an embodiment, the substrate 120 may be formed of a silicon material, a synthetic resin material, or a metal material, and may be formed as a thermally conductive substrate so as to discharge heat generated in the light emitting device 140 to the outside .

The first electrode 120a and the second electrode 120b are formed on the substrate 120 to correspond to the first and second electrode pads 140a and 140b of the light emitting device to be described later. The first electrode 120a and the second electrode 120b are provided as penetrating electrodes passing through the substrate 120 and are electrically isolated from each other to supply power to the light emitting device 140. [

In addition, the light emitting device 140 is provided as a flip chip, and emits light in a side emitting light pattern.

The light emitting element 140 includes a light emitting structure 148 in which a light transmitting substrate 144 and a plurality of semiconductor compounds are stacked and is vertically disposed on the top of the substrate 120 in a direction in which semiconductor compounds are stacked . The transparent substrate 144 may be a sapphire substrate or the like, and may include a light-transmitting conductive substrate or an insulating substrate, but is not limited thereto.

The transparent substrate 144 may be formed of a highly thermally conductive material, sapphire (Al ₂ O ₃₎ in addition to SiO _2, SiC, Si, GaAs, GaN, ZnO, GaP, InP, Ge, Ga ₂ 0 ₃ of at least You can use one.

One surface of the transparent substrate 144 may include an inclined surface 144a so that the light emitted from the light emitting device 140 can be implemented in a side emitting pattern. (148).

Here, the light emitted from the light emitting device can control the path according to the inclination of the inclined surface 144a formed on the transparent substrate 144.

In the embodiment, when the inclined surface 144a is inclined at 45 to 60 degrees with respect to the surface of the light emitting structure 148, the directivity angle of the light emitted from the light emitting element 140 is wide, and high optical efficiency can be obtained.

Thus, the light emitted from the light emitting element 140 is emitted to the side through the inclined surface 144a of the transparent substrate 144. Therefore, it is possible to emit light having a desired light amount distribution in the lateral direction with a very simple structure, without using a lens or the like, which is additionally required in order to cause light emitted from the light emitting element to be emitted to the front surface as a side, As shown in FIG.

The light emitting structure 148 is provided under the buffer layer 148a and the buffer layer 148a provided below the transparent substrate 144 and includes a first conductive semiconductor layer including the first electrode pad 140a An active layer 148c provided under the first conductive type semiconductor layer 148b and a second conductive type semiconductor layer 148d provided under the active layer 148c and including a second electrode pad 140b, ).

The light emitting structure 148 including the first conductive semiconductor layer 148b, the active layer 148c and the second conductive semiconductor layer 148d may be formed by a metal organic chemical vapor deposition (MOCVD) (CVD), a plasma enhanced chemical vapor deposition (PECVD), a molecular beam epitaxy (MBE), a hydride vapor phase epitaxy (HVPE) ), And the like, but the present invention is not limited thereto.

A buffer 148a can be grown between the first conductivity type semiconductor layer 148b and the transparent substrate 144 to mitigate the difference in lattice mismatch and thermal expansion coefficient of the material. The material of the buffer layer 148a may be at least one of Group III-V compound semiconductor such as GaN, InN, AlN, InGaN, AlGaN, InAlGaN, and AlInN. An undoped semiconductor layer may be formed on the buffer layer 148a, but the present invention is not limited thereto.

In addition, the first conductive semiconductor layer 148b may be formed of a semiconductor compound. More specifically, the compound semiconductor may be implemented by a compound semiconductors such as Group 3-Group 5, Group 2-Group 6, and the like, and the first conductivity type dopant may be doped. When the first conductive type semiconductor layer 148b is an n-type semiconductor layer, the first conductive type dopant may include Si, Ge, Sn, Se, and Te as n-type dopants, but is not limited thereto.

The first conductivity type semiconductor layer 148b is formed of a semiconductor material having a composition formula of Al _x In _y Ga _(1-xy) N (0? X? 1, 0? _Y? 1, 0? _X + . ≪ / RTI > The first conductive semiconductor layer 148b may be formed of one or more of GaN, InN, AlN, InGaN, AlGaN, InAlGaN, AlInN, AlGaAs, InGaAs, AlInGaAs, GaP, AlGaP, InGaP, AlInGaP and InP.

On the other hand, the active layer 148c is formed in such a manner that the electrons injected through the first conductive type semiconductor layer 148b and the holes injected through the second conductive type semiconductor layer 148d formed thereafter mutually meet to form the active layer 148c, Which emits light having energy determined by the energy band of the light.

The active layer 148c may be a double heterostructure structure, a single quantum well structure, a multi quantum well (MQW) structure, a quantum-wire structure, or a quantum dot structure. Or the like. For example, the active layer 148c may be formed by injecting trimethyl gallium gas (TMGa), ammonia gas (NH ₃ ), nitrogen gas (N ₂ ), and trimethyl indium gas (TMIn) to form a multiple quantum well structure But is not limited thereto.

The well layer / barrier layer of the active layer 148c may be formed of any one of InGaN / GaN, InGaN / InGaN, GaN / AlGaN, InAlGaN / GaN, InAlGaN / InAlGaN, GaAs (InGaAs) / AlGaAs, GaP But it is not limited thereto. Here, the well layer may be formed of a material having a band gap lower than the band gap of the barrier layer.

A conductive clad layer (not shown) may be formed on and / or below the active layer 148c. The conductive cladding layer may be formed of a semiconductor having a band gap wider than the barrier layer or band gap of the active layer 148c. For example, the conductive clad layer may include GaN, AlGaN, InAlGaN, superlattice structure, or the like. Further, the conductive clad layer may be doped with n-type or p-type.

In addition, the second conductivity type semiconductor layer 148d may be formed of a semiconductor compound. More specifically, the semiconductor layer may be formed of a compound semiconductors such as Group 3-Group 5, Group 2-Group 6, and the like, and the second conductivity type dopant may be doped. For example, it may include a semiconductor material having a composition formula of In _x Al _y Ga _1-xy N (0? X? 1, 0? _Y? 1, 0? _X + y? When the second conductivity type semiconductor layer 148d is a p-type semiconductor layer, the second conductivity type dopant may include Mg, Zn, Ca, Sr, and Ba as a p-type dopant.

The first electrode pad 140a of the light emitting device 140 is disposed on the exposed surface of a part of the first conductive semiconductor layer 148b and the second electrode pad 140b And is disposed on one side of the lower surface of the second conductivity type semiconductor layer 148d. Here, ITO (Indium Tin Oxide) 147 may be further included between the lower end surface of the second conductive type semiconductor layer 148d and the second electrode pad 140b to increase the conductivity.

The first electrode pad 140a and the second electrode pad 140b may include at least one of aluminum (Al), titanium (Ti), chrome (Cr), nickel (Ni), copper (Cu) Layer structure or a multi-layer structure.

The first and second electrode pads 140a and 140b of the light emitting device 140 are soldered to the first electrode 120a and the second electrode 120b of the substrate 120 and are electrically connected to each other.

A solder 160 is provided between the first electrode 120a and the first electrode pad 140a and between the second electrode 120b and the second electrode pad 140b and is soldered. Free solder and high lead of Sn / Ag, Sn / Cu, Sn / Zn, Sn / Zn / Bi, Sn / Ag / Cu, Sn / Ag / and eutectic lead solder.

In addition, the passivation layer 145 may be made of an insulating material, and more specifically, may be made of an oxide or a nitride. More specifically, the passivation layer 145 may include a silicon oxide (SiO ₂ ) layer, an oxynitride layer, .

4A to 4D illustrate a process of the light emitting device package according to the first embodiment.

4A, a light emitting structure 148 including a buffer layer, a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer is grown on a transparent substrate 144. Here, the light-emitting structure may include, for example, a metal organic chemical vapor deposition (MOCVD), a chemical vapor deposition (CVD), a plasma enhanced chemical vapor deposition (PECVD) A molecular beam epitaxy (MBE), a hydride vapor phase epitaxy (HVPE), or the like. However, the present invention is not limited thereto.

On the other hand, the transparent substrate 144 may be formed of a material suitable for semiconductor material growth, such as a carrier wafer, including a light-transmitting conductive substrate or an insulating substrate, for example, sapphire (Al ₂ O ₃ ). The concavo-convex structure may be formed on the light-transmitting substrate, but not limited thereto, and the light-transmitting substrate may be wet-cleaned to remove impurities on the surface.

The first and second electrode pads 140a and 140b electrically connected to a substrate to be described later are disposed in the light emitting structure 148. [

The transparent substrate 144 is etched so that the inclined surface can be formed on the upper surface of the transparent substrate 144, as shown in FIG. 4B.

In the embodiment, the translucent substrate 144 can be fixed to the support sheet S, and the translucent substrate 144 can be etched using a photoresist. At this time, the amount of photoresist is differently applied to the surface of the transparent substrate 144 in accordance with the inclination of the inclined surface 144a of the transparent substrate 144, and then the transparent substrate 144 can be etched by irradiating light have.

In addition, in the case of the transparent substrate 144 made of sapphire, wet etching can be performed using an etching solution such as sulfuric acid or phosphoric acid, and the transparent substrate 144 can be physically processed to be a translucent substrate 144 having an inclined surface.

The light emitted from the light emitting device can control the path along the inclination of the inclined surface 144a formed on the transparent substrate 144. In an embodiment, the inclined surface 144a is formed on the surface of the light emitting structure 148 The angle of incidence of the light emitted from the light emitting element 140 is wide and a high optical efficiency can be obtained.

Referring to FIG. 4C, after the etching process for providing the inclined surface 144a, the substrate is diced into each light emitting device unit.

4D, when the light emitting device 140 disposed on the substrate 120 is a blue flip chip, the passivation layer 145 may be provided on the surface of the light emitting structure 148 The passivation layer 145 may be made of an insulating material and may be made of an oxide or a nitride and more specifically may be formed of a silicon oxide (SiO ₂ ) layer, an oxynitride layer, have.

If the light emitting device 140 disposed on the substrate 120 is a white flip chip, a phosphor layer (not shown) may be further provided on the surface of the transparent substrate 144.

Here, the phosphor layer may be coated on the surface of the transparent substrate 144 in a conformal manner with good uniformity of light, but not limited thereto. Further, the thickness of the phosphor layer may be coated differently depending on the amount of emitted light, instead of being coated with the same thickness on the inclined surface and the side surface of the transparent substrate 144.

The first and second electrode pads 140a and 140b of the light emitting device 140 are electrically connected to the first electrode 120a and the second electrode 120b of the substrate 120, And are electrically connected to the second electrode 120b by soldering.

According to the above-described embodiment, light can be totally reflected from the inclined surface formed on the light-transmitting substrate, and the inclined surface is provided on the substrate of the light-emitting device, so that the light- A side-emitting light pattern can be obtained.

In order to obtain a site-emitting light pattern, a chip size package (CSP) is formed by attaching the light emitting device directly to the substrate of the light emitting device package without providing a lens or a diffuser, Therefore, the fabrication cost can be reduced by simplifying the manufacturing process of the light emitting device package.

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 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.

10, 100: light emitting device package 11, 120:
12a: first lead frame 12b: second lead frame
13: bonding layer 14, 140: light emitting element
15: wire 16: molding part
17, 146: phosphor layer 120a: first electrode
120b: second electrode 140a: first electrode pad
140b: second electrode pad 144: transparent substrate
144a: inclined surface 145: passivation layer
148: light emitting structure 148a: buffer layer
148b: first conductivity type semiconductor layer 148c:
148d: second conductivity type semiconductor layer 160: solder

Claims (9)

A substrate having a first electrode and a second electrode; And
A light emitting structure including a first conductivity type semiconductor layer, an active layer and a second conductivity type semiconductor layer; a first electrode pad provided on each of the first conductivity type semiconductor layer and the second conductivity type semiconductor layer; And a light emitting element including a second electrode pad and flip-bonded on the substrate,
Wherein the light transmitting substrate has a sloped surface formed on a surface opposite to the light emitting structure. The method according to claim 1,
Wherein the substrate is a thermally conductive substrate. The method according to claim 1,
Wherein the light-transmitting substrate is a sapphire. The method according to claim 1,
Wherein the inclined surface has an inclination of 45 to 60 degrees with respect to a surface of the light emitting structure. The method according to claim 1,
And a phosphor layer disposed on a surface of the transparent substrate. 6. The method of claim 5,
Wherein the phosphor layer is conformal-coated on a surface of the translucent substrate. The method according to claim 6,
And the phosphor layer is disposed on the inclined surface and the side surface of the transparent substrate. The method according to claim 1,
Wherein the first electrode pad is disposed on a portion of the first conductive semiconductor layer that is partly exposed by mesa etching and the second electrode pad is disposed on one side of the lower surface of the second conductive semiconductor layer. The method according to claim 1,
Wherein the first and second electrode pads of the light emitting device are respectively soldered to the first electrode and the second electrode of the substrate.

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