WO2016032194A1 - Light emitting diode - Google Patents

Abstract

The present invention relates to a light emitting diode, and more specifically, to a light emitting diode in which a bonding pad is soldered to a mounting substrate, wherein the light emitting diode has a bonding pad shape that can minimize the occurrence of voids during soldering.

Description

Light emitting element

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device, and more particularly, to a light emitting device having a bonding pad shape capable of minimizing voids generated during soldering in a light emitting device in which a bonding pad is soldered onto a mounting substrate.

In order to obtain a high output light emitting device, the device must be manufactured in consideration of factors such as increasing luminous efficiency, miniaturizing a package, and lowering thermal resistance. In order to satisfy the above conditions, a flip chip type light emitting device is widely used at present.

The flip chip method refers to a chip bonding method using solder bumps. Since the bonding length is almost smaller than that of the conventional wire bonding method, the inductance due to the bonding can be reduced to 1/10 or less, thus According to the method, the chip package can be integrated.

In other words, in the flip chip method, light is emitted toward the substrate to eliminate light loss from the electrode pad, and by depositing a reflective film on the p-layer, the extraction efficiency can be improved by changing the path of the photons traveling toward the mounting substrate in the opposite direction. have. The flip-chip approach also improves current spreading, providing a low forward voltage.

In addition, in the case of a high output light emitting device, a lot of heat is generated when the injection current is increased. Since the distance from the active layer, which is a heat generating region, to the heat dissipation structure is close, heat dissipation is easy and heat resistance is greatly reduced. Therefore, in the high output device such as a large area light emitting device, the flip chip method is adopted.

On the other hand, various structures have been proposed for large area light emitting devices in which a flip chip method is widely used to help current dispersing. The active layer interposed between the first conductive semiconductor layer and the second conductive semiconductor layer is separated into two or more. Also, a form in which the two or more active layers share one first conductive semiconductor layer is also known.

In the flip chip method, a solder bump is melted by applying a high temperature heat source to electrically connect the bonding pads of the chip and the mounting substrate. The process of melting the solder bumps is called reflow.

During the reflow process, when the flux evaporates and the molten solder solidifies, bubbles may be trapped inside, resulting in voids. Voids are the biggest cause of weakening the heat dissipation function and deterioration of the reliability of the light emitting device due to poor bonding between the bonding pad of the chip and the mounting substrate.

Therefore, in order to improve the reliability of the light emitting device, a technique for minimizing void generation is required.

In connection with the present invention, Korean Patent Publication No. 10-2013-0030178 (published on March 26, 2013) discloses a large area light emitting device employing a flip chip method.

SUMMARY OF THE INVENTION An object of the present invention is to provide a light emitting device having a bonding pad shape in which a bonding pad is soldered on a mounting substrate, thereby minimizing void generation occurring during the soldering process.

Another object of the present invention is to provide a light emitting device in which defects that may occur in the soldering process are minimized.

In the light emitting device according to the embodiment of the present invention, a bonding pad is soldered onto a mounting substrate, and the bonding pad is electrically connected to the first conductive semiconductor layer and the second conductive semiconductor layer by a connection electrode, respectively. Two or more linear bonding pads are connected to the first electrode and the second electrode and have a solder ball contact area, and at least two of the two or more linear bonding pads face each other and face each other. The non-conductive region is present between the two bonding pads.

The light emitting device according to another embodiment of the present invention is a bonding pad is soldered on a mounting substrate, and the bonding pad is electrically connected to the first conductive semiconductor layer and the second conductive semiconductor layer by a connecting electrode, respectively. The first and second electrodes may be connected to each other, and a bonding pad may be formed in a portion of the solder ball contactable area, and a non-conductive pattern for void escape may be formed in the remaining area of the solder ball contactable area.

According to the light emitting device of the present invention, the voids generated during the soldering process are minimized because a large void is not formed or the bonding pad shape can be easily escaped without being trapped in the bonding pad. Can be improved. In addition, the reliability of the light emitting device can be improved by covering the portion of the first electrode positioned on the portion where the first electrode and the first conductive semiconductor layer of the light emitting device are in contact with the bonding pad.

1A is a plan view of a light emitting device having a bonding pad shape according to an embodiment of the present invention.

FIG. 1B is a cross-sectional view when the light emitting device of FIG. 1A is cut in the A'-A direction.

2 to 6 and 8 are plan views of a light emitting device including an electrode shape according to various embodiments of the present disclosure.

FIG. 7A is a cross-sectional view when the light emitting device of FIG. 3 is cut in the direction of BB '. FIG.

FIG. 7B is a cross-sectional view when the light emitting device of FIG. 3 is cut in the direction C-C '. FIG.

9 to 14 are plan views and cross-sectional views for describing a light emitting device according to another embodiment of the present invention.

15 and 16 are plan views illustrating light emitting devices according to another exemplary embodiment of the present invention.

17 is an exploded perspective view illustrating an example in which a light emitting device according to an embodiment of the present invention is applied to a lighting device.

18 is a cross-sectional view illustrating an example in which a light emitting device according to an embodiment of the present invention is applied to a display device.

19 is a cross-sectional view illustrating an example in which a light emitting device according to an embodiment of the present invention is applied to a display device.

20 is a cross-sectional view illustrating an example in which a light emitting device according to an embodiment of the present invention is applied to a head lamp.

Advantages and features of the present invention, and methods for achieving them will be apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various forms, and only the present embodiments are intended to complete the disclosure of the present invention, and are commonly known in the art. It is provided to fully inform the scope of the invention to those having the present invention, the invention is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

Hereinafter, a light emitting device according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1A is a plan view of a light emitting device having a bonding pad shape according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view when the light emitting device of FIG. 1A is cut in the A'-A direction.

First, referring to FIG. 1, the light emitting device including the electrode shape of the present invention may be formed on the substrate 101 such that the active layer 112 is interposed between the n-type semiconductor layer 111 and the p-type semiconductor layer 113. The first conductive semiconductor layer 111, the active layer 112, and the second conductive semiconductor layer 113 are formed.

The substrate 101 may be selected from a known material such as Al ₂ O ₃ , SiC, Si, GaAs, GaN, ZnO, GaP, InP, Ge, or the like. Concave-convex patterns may be formed on and / or under the substrate 101, and the concave-convex pattern may be freely selected, such as a stripe shape, a lens shape, a pillar shape, or a horn shape.

The first conductivity type semiconductor layer 111 is a semiconductor layer doped with the first conductivity type dopant. The first conductive semiconductor layer 111 may be formed of at least one of GaN, InN, AlN, InGaN, AlGaN, and InAlGaN, and the first conductive semiconductor layer 111 may be an n-type semiconductor layer. The single-conducting dopant may include at least one of Si, Ge, Sn, Se, and Te, which are n-type dopants.

The active layer 112 may be formed in a single quantum well or multiple quantum well (MQW) structure. That is, at least one of GaN, InN, AlN, InGaN, AlGaN, and InAlGaN may be formed using a Group III-V compound semiconductor material. For example, the active layer 112 may have a structure in which InGaN well layers / GaN barrier layers are alternately formed. The active layer 112 generates light while the carrier supplied from the first conductive semiconductor layer 111 and the carrier supplied from the second conductive semiconductor layer 113 are recombined. When the first conductivity-type semiconductor layer 111 is an n-type semiconductor layer, the carrier supplied from the first conductivity-type semiconductor layer 111 may be electrons, and the second conductivity-type semiconductor layer 113 may be p-type. In the case of the semiconductor layer, the carrier supplied from the second conductivity type semiconductor layer 113 may be a hole.

The second conductivity type semiconductor layer 113 may include a semiconductor layer doped with the second conductivity type dopant and may be formed in a single layer or multiple layers. The second conductive semiconductor layer 113 may be formed of at least one of GaN, InN, AlN, InGaN, AlGaN, and InAlGaN, and when the second conductive semiconductor layer 113 is a p-type semiconductor layer, the second The conductive dopant may include one or more of p-type dopants, Mg, Zn, Ca, Sr, and Ba.

In addition to the first conductive semiconductor layer 111, the active layer 112, and the second conductive semiconductor layer 113 shown in FIG. 1, the light emitting device according to the present invention may include an undoped layer or other buffer layer to improve crystal quality. When the second conductive semiconductor layer 113 is a p-type semiconductor layer, various functional layers such as an electron blocking layer (not shown) formed between the active layer 112 and the second conductive semiconductor layer 113 may be used. May be included.

The nitride based semiconductor stack 110 may include an exposed region e partially exposing the first conductive semiconductor layer 111, and the first conductive semiconductor layer 111 may be exposed through the exposed region e. The first electrode 140 may be electrically connected. The current dispersion efficiency and the light emission pattern of the light emitting device may be adjusted according to the position, shape, and number of the exposed regions e. The exposed area e may be formed using photo and etching techniques. The exposed area e may be formed using photo and etching techniques. For example, an exposed region e may be formed by defining an etching region using a photoresist and etching the second conductive semiconductor layer 113 and the active layer 112 using dry etching such as ICP. .

Although not limited thereto, FIG. 1B illustrates an example in which the exposed region e is formed in a hole shape penetrating through the active layer 112 and the second conductive semiconductor layer 113. The first conductive semiconductor layer 111 and the first electrode 140 are electrically connected through the hole. Holes may be formed regularly as shown, but the present invention is not limited thereto. The current dispersion efficiency and the light emission pattern of the light emitting device may be adjusted according to the position, shape, and number of holes.

The second electrode 120 is positioned on the second conductive semiconductor layer 113 and may be electrically connected to the second conductive semiconductor layer 113. The second electrode 120 may include the reflective metal layer 121, and further include the barrier metal layer 122, and the barrier metal layer 122 may cover the top and side surfaces of the reflective metal layer 121. For example, by forming a pattern of the reflective metal layer 121 and forming the barrier metal layer 122 thereon, the barrier metal layer 122 may be formed to cover the top and side surfaces of the reflective metal layer 121. For example, the reflective metal layer 121 may be formed by depositing and patterning an Ag, Ag alloy, Ni / Ag, NiZn / Ag, or TiO / Ag layer.

Meanwhile, the barrier metal layer 122 may be formed of Ni, Cr, Ti, Pt, or a composite layer thereof to prevent the metal material of the reflective metal layer 121 from being diffused or contaminated. In addition, the second electrode 120 may include indium tin oxide (ITO), zinc oxide (ZnO), or the like. Since ITO or ZnO is made of a metal oxide having a high light transmittance, light absorption by the second electrode 120 may be suppressed to improve luminous efficiency. The first electrode 140 may include a first conductive semiconductor layer 111. Can be electrically connected to. The first electrode 140 may cover the nitride based semiconductor stack 110. In addition, the first electrode 140 may have an opening 140b exposing the second electrode 120. The first electrode 140 may be formed on an almost entire area of the growth substrate 100 except for the opening 140b. Thus, current may be easily dispersed over the entire area of the growth substrate 100 through the first electrode 140. The first electrode 140 may include a high reflective metal layer such as an Al layer, and the high reflective metal layer may be formed on an adhesive layer such as Ti, Cr, or Ni. In addition, a protective layer of a single layer or a composite layer structure such as Ni, Cr, Au, or the like may be formed on the highly reflective metal layer. The first electrode 140 may have, for example, a multilayer structure of Ti / Al / Ti / Ni / Au. The first electrode 140 may be formed by depositing and patterning a metal material on the nitride-based semiconductor stack 110.

The light emitting device according to the present embodiment may further include a lower insulating layer 130. The lower insulating layer 130 covers the top surface and side surfaces of the nitride-based semiconductor stack 110 and the second electrode 120, and is positioned between the nitride-based semiconductor stack 110 and the first electrode 140. Thus, the first electrode 140 may be insulated from the second electrode 120. The lower insulating layer 130 has openings 130a and 130b for allowing electrical connection to the first conductive semiconductor layer 111 and the second conductive semiconductor layer 113 in a specific region. For example, the lower insulating layer 130 may have an opening 130a exposing the first conductive semiconductor layer 111 and an opening 130b exposing the second electrode 120. The opening 130b of the lower insulating layer 130 may have a relatively narrow area than the opening 140b of the first electrode 140. The lower insulating layer 130 may be formed of an oxide film such as SiO 2, a nitride film such as SiNx, or an insulating film of MgF 2 using a technique such as chemical vapor deposition (CVD). The lower insulating layer 130 may be formed of a single layer, but is not limited thereto and may be formed of multiple layers. Further, the lower insulating layer 130 may include a distributed Bragg reflector (DBR) in which the low refractive material layer and the high refractive material layer are alternately stacked. For example, an insulating reflective layer having a high reflectance can be formed by laminating layers such as SiO 2 / TiO 2 or SiO 2 / Nb 2 O 5.

The light emitting device according to the present embodiment may further include an upper insulating layer 150. The upper insulating layer 150 may cover a portion of the first electrode 140. The upper insulating layer 150 may have an opening 150a exposing the first electrode 140 and an opening 150b exposing the second electrode 120. The opening 150b of the upper insulating layer 150 may have a relatively narrower area than the opening 140b of the first electrode 140 and the opening 130b of the lower insulating layer 130. Accordingly, sidewalls of the opening 130b of the lower insulating layer 130 may be covered by the upper insulating layer 150 as well as sidewalls of the opening 140b of the first electrode 140. In this case, the second electrode 120 may be more effectively protected from moisture. In detail, even if the second electrode 120 does not include the barrier metal layer, external moisture may be prevented from penetrating into the reflective metal layer of the second electrode 120. However, the present disclosure is not limited thereto, and the upper insulating layer 150 may be formed by depositing and patterning an oxide insulating layer, a nitride insulating layer, or a polymer such as polyimide, teflon, and parylene on the first electrode 140. have.

The bonding pad of the light emitting device according to the present exemplary embodiment may include a first bonding pad 200a and a second bonding pad 200b electrically connected to the first electrode 140 and the second electrode 120, respectively. . Although not limited thereto, referring to FIG. 1B, the first bonding pad 200a may be connected to the first electrode 140 through a first connection electrode formed in the opening 150a of the upper insulating layer 150. The 2 bonding pads 200b may be connected to the second electrode 120 through the second connection electrode formed in the opening 150b of the upper insulating layer 150. The first bonding pad 200a and the second bonding pad 200b may serve to effectively connect the first electrode 140 and the second electrode 120 to the substrate. The first bonding pad 200a and the second bonding pad 200b may be formed together in the same process, for example, by using a photo and etching technique or a lift off technique. The first bonding pad 200a and the second bonding pad 200b may include, for example, an adhesive layer such as Ti, Cr, or Ni, and a highly conductive metal layer such as Al, Cu, Ag, or Au.

Meanwhile, the light emitting device including the bonding pads 200a and 200b of the present invention may have a form in which a plurality of separated active layers share one first conductive semiconductor layer 111.

When the first bonding pad 200a and the second bonding pad 200b are designed to occupy the largest area in the solder ball contactable area 210 to facilitate bonding between the mounting substrate and the bonding pad, they may occur during the reflow process. Since the voids deteriorate the reliability of the light emitting device, it is necessary to design an electrode shape in which large voids are not formed or the voids can escape well without being trapped in the electrode.

According to this necessity, the light emitting device having the electrode shape according to the present invention has the bonding pads 200a and 200b soldered onto the mounting substrate, as shown in FIGS. 1 to 6. Two or more linear bonding pads 200a and 200b are electrically connected to the first conductive semiconductor layer 111 and the second conductive semiconductor layer 113 by connecting electrodes, respectively, in the solder ball contactable area 210. Is formed, and at least two of the two or more linear bonding pads 200a and 200b face each other, and a non-conductive area 220 is disposed between the two bonding pads 200a and 200b facing each other. It is characterized by the presence.

Here, the solder ball contactable area 210 refers to a portion where the light emitting device may contact the solder ball located on the mounting substrate. When the solder is melted by the reflow process, the solder ball contactable area 210 is melted. It may be included in the area occupied by the solder.

Since the content corresponding to the first bonding pad 200a is also applied to the second bonding pad 200b as it is, the bonding pad of the present invention will be described below with reference to the first bonding pad 200a.

Here, the linear bonding pad 200a means that the length of the electrode having an area is larger than the width.

Here, the non-conductive region 220 is a region where the bonding pad 200a is not formed and means a portion where the upper insulating layer 150 is exposed. That is, the space due to the step between the upper insulating layer 150 and the bonding pad 200a layer corresponds to this.

Herein, the bonding pads face each other as long as the bonding pads can be recognized as facing each other in parallel or even if they are not parallel.

That is, in the bonding pad 200a of the light emitting device of the present invention, at least two of the two or more linear bonding pads 200a face each other, but the non-conductive area 220 is disposed between the two electrodes facing each other. By being present, void generation is minimized.

Specifically, as shown in FIG. 1A, at least two of the two or more linear bonding pads 200a may be spaced apart from each other.

In addition, as shown in FIG. 2, at least two of the two or more linear bonding pads 200a may be connected to each other.

In addition, the linear bonding pads shown in FIG. 1A may be all connected at any position by the connection unit as shown in FIGS. 3 to 6.

3, for example, all four bonding pads 200a having three linear shapes are connected to each other through three connection portions. That is, as shown in Figures 3 to 6, if the two or more linear bonding pads 200a are formed (n≥2), when at least n-1 or more connection parts are included, the linear shape The bonding pads 200a may be connected to each other.

In addition to the shapes shown in FIGS. 3 to 6, the linear bonding pads 200a may be connected with more connections as long as the condition that the non-conductive area 220 exists between the two bonding pads facing each other.

That is, in the bonding pad included in the light emitting device of the present invention, at least two of the two or more linear bonding pads 200a face each other, but are not electrically conductive between two bonding pads 200a facing each other. The presence of the region 220 exposes the upper portion of the insulating layer 150, thereby providing a space due to the step between the insulating layer 150 and the bonding pad 200a layer, thereby creating a large void generated in the reflow process. It is designed so that it is not formed.

7A and 7B show cross-sectional views of the light emitting device of FIG. 3 in the B-B 'and C-C' directions, respectively, and the above-described effects can be confirmed.

As shown in FIG. 7A, the second bonding pad 200b of the present invention has a non-conductive area 220 between linear bonding pads facing each other, that is, the insulating layer 150 and the bonding pad. (200b) As the space due to the step between the layers, the voids generated in the reflow process is released to the space, the reliability of the product can be improved.

Similarly, as can be seen in FIG. 7B, the first bonding pad 200a of the present invention has a non-conductive area 220 between the linear bonding pads facing each other, that is, the insulating layer 150 and the bonding layer. As the space due to the step between the pads 200a, the voids generated in the reflow process are released to the space, thereby improving the reliability of the product.

The width t of the linear bonding pad 200a is preferably 200 μm or less. If the above range is exceeded, the distance from the void presence point generated in the solder ball contactable area 210 in the bonding pad 200a to the non-conductive area becomes too far, so that the void does not escape and is trapped in the bonding pad 200a. As a result, the reliability of the light emitting device is reduced, such as poor bonding to the mounting substrate and poor heat dissipation performance.

Moreover, it is preferable that the width | variety t of the linear bonding pad 200a is 40 micrometers or more. If it is less than the above range there is a problem that the current injection amount to the bonding pad 200a is lowered to reduce the luminous efficiency of the light emitting device.

In addition, the area of the linear bonding pad 200a is preferably 40% or more of the solder ball contactable area 210. If it is less than the above range there is a problem that the current injection amount to the bonding pad 200a is lowered to reduce the luminous efficiency of the light emitting device.

The shape of the bonding pad of the present invention is not limited to the above-described embodiments, and those skilled in the art can deform as many as possible within the scope of the present invention in terms of designing such that voids having a diameter of an electrode width or more are not generated.

Accordingly, in the light emitting device having the electrode shape according to another exemplary embodiment of the present invention, as shown in FIG. 8, bonding pads 200a and 200b are soldered onto the mounting substrate. ) Is connected to the first electrode 140 and the second electrode 120 electrically connected to the first conductivity type semiconductor layer and the second conductivity type semiconductor layer, respectively, by the connecting electrode, and among the solder ball contactable areas 210. A bonding pad 200a is formed in a portion of the solder pad, and a non-conductive pattern 230 for void escape is formed in the remaining portion of the solder ball contactable region 210.

Here, the void escape non-conductive pattern 230 corresponds to an area in which the bonding pads 200a and 200b are not formed. The upper portion of the insulating layer 150 is exposed to expose the upper insulating layer 150 and the bonding pad ( 200a, 200b) because the space is provided by the step between the layers, it means a form of the space that the void generated in the reflow process can escape.

That is, in the bonding pads 200a and 200b of the light emitting device of the present invention, the bonding pads 200a and 200b are formed in some of the solder ball contactable regions 210, and the remaining bonding pads 200a and 200b are formed in the remaining solder ball contactable regions 210. By forming the void escape non-conductive pattern 230, the voids may escape through the non-conductive pattern 230, thereby minimizing the occurrence of voids.

Specifically, as shown in FIG. 8, the non-conductive pattern 230 may be formed in the direction of the edge of the solder ball contactable region 210 within 200 μm at an arbitrary point P in the bonding pads 200a and 200b. have. The void generated through this can be immediately exited through the non-conductive pattern 230.

That is, if the thickness exceeds 200 μm at any point P in the electrode, it is difficult for the voids to escape, so it is preferable to form the void-free non-conductive pattern 230 for void escape without forming the electrode so that the voids can escape. .

The non-conductive pattern 230 may have a tapered shape that extends toward the edge of the solder ball contactable region 210.

When the non-conductive pattern 230 has a tapered shape that becomes wider toward the edge portion of the solder ball contactable region 210, the voids may easily escape.

In addition, the area of the bonding pads 200a and 200b is preferably 40% or more of the area of the solder ball contactable area 210. If it is less than the above range, there is a problem that the current injection amount to the electrode is lowered to reduce the luminous efficiency of the light emitting device.

9 to 14 are plan views and cross-sectional views for describing a light emitting device according to another embodiment of the present invention. Specifically, FIG. 9 is a plan view illustrating a plane of the light emitting device, and FIG. 10 is a plan view omitting bonding pads 200a and 200b for convenience of description, and FIG. 11 is a bonding view for convenience of description. The pads 200a and 200b, the upper insulating layer 150, the first electrode 140, and the lower insulating layer 130 are omitted. FIG. 12 shows a cross section of a portion corresponding to line AA ′ of the top views of FIGS. 9 to 11, and FIG. 13 shows a cross section of a portion corresponding to line B-B ′ of the top views of FIGS. 9 to 11. 14 shows a cross section of a portion corresponding to line C-C 'of the plan views of FIGS.

The light emitting device according to the present embodiment has a difference in the structure of the bonding pads 200a and 200b and the structure of the nitride-based semiconductor stack 110 compared to the embodiments described with reference to FIGS. 1 to 8. Hereinafter, the light emitting device of the present embodiment will be described based on differences, and detailed descriptions of the same components will be omitted.

9 to 14, the light emitting device includes a nitride based semiconductor stack 110, a first electrode 140, a second electrode 120, a first bonding pad 200a, and a second bonding pad 200b. It includes. Further, the light emitting device may further include a lower insulating layer 130, an upper insulating layer 150, and a substrate 101. In addition, the light emitting device may have a rectangular planar shape. In the present embodiment, the light emitting device may have a generally square planar shape, and the third side surface 100c positioned opposite to the first side surface 100a, the second side surface 100b, and the first side surface 100a. And a fourth side surface 100d positioned opposite to the second side surface 100b. However, the present invention is not limited thereto.

The nitride based semiconductor layer 110 includes a first conductive semiconductor layer 111, an active layer 112 positioned on the first conductive semiconductor layer 111, and a second conductive semiconductor layer positioned on the active layer 112. (113). In addition, the nitride-based semiconductor stack 110 may include regions 110a and 110b partially exposing the first conductivity-type semiconductor layer 111. The current dispersion efficiency and the light emission pattern of the light emitting device may be adjusted according to the position, shape, and number of the exposed areas 110a and 110b.

Referring to FIG. 11, regions 110a, 110b and 110c where the first conductivity type semiconductor layer 111 is partially exposed may include holes. The holes may include a first hole 110a, a second hole 110b, and a third hole 110c. A plurality of first holes 110a, second holes 110b, and third holes 110c may be formed. The first hole 110a may have a planar shape of a generally circular or polygonal shape. The second hole 110b may have substantially the same shape as the first hole 110a. The third hole 110c may be formed to extend in an arbitrary direction from the second hole 110b. In this case, the third hole 110c and the second hole 110b may be connected to each other. In addition, the width of the third hole 110c may be smaller than the width of the first hole 110a and the second hole 110b.

For example, as shown, the first hole 110a has a circular planar shape and may be formed in plural. The third hole 110c may extend from the second hole 100b and may extend from the first side surface 100a toward the third side surface 100c and may be formed in plural. At least a portion of the third hole 110c may be formed to extend from a lower portion of the first bonding pad 200a to a lower portion of the second bonding pad 200b.

The second electrode 120 may be positioned on the nitride-based semiconductor stack 110 to make ohmic contact with the second conductive semiconductor layer 113. The second electrode 120 may include openings exposing the first and second holes 110a and 110b, so that the second electrode 120 may be connected to the first and second holes 110a and 110b. Can be spaced apart.

The lower insulating layer 130 may cover the top and side surfaces of the nitride based semiconductor stack 110 and the second electrode 120. In this case, the lower insulating layer 130 may have openings 130a and 130b for allowing electrical connection to the first conductive semiconductor layer 111 and the second conductive semiconductor layer 113 in a specific region. For example, the lower insulating layer 130 may have a first opening 130a exposing the first conductive semiconductor layer 111 and a second opening 130b exposing the second electrode 120.

The first electrode 140 may be electrically connected to the first conductive semiconductor layer 111, and in particular, the first electrode 140 may be in ohmic contact with the first conductive semiconductor layer 111. The first electrode 140 may be electrically connected to the first conductivity type semiconductor layer 111 through the first and second holes 110a and 110b. Accordingly, the portion into which the current is injected into the nitride based semiconductor stack 110 through the first electrode 140 may be controlled according to the position and shape of the first and second holes 110a and 110b. In addition, the first electrode 140 may have an opening 140b exposing the second electrode 120. The first electrode 140 may be formed on an almost entire area of the growth substrate 100 except for the opening 140b.

The upper insulating layer 150 may cover a portion of the first electrode 140. The upper insulating layer 150 may include a third opening 150a exposing the first electrode 140 and a fourth opening 150b exposing the second electrode 120. The fourth opening 150b of the upper insulating layer 150 may have a relatively narrower area than the opening 140b of the first electrode 140 and the opening 130b of the lower insulating layer 130. In the present embodiment, the upper insulating layer 150 covers a portion of the first electrode 140 positioned on the third hole 110c. Accordingly, the third opening 150a of the upper insulating layer 150 may partially expose the first electrode 140 positioned on the first hole 110a and / or the second hole 110b.

The first bonding pad 200a and the second bonding pad 200b may be electrically connected to the first electrode 140 and the second electrode 120, respectively. Referring to FIG. 10, the first bonding pad 200a may contact the first electrode 140 through the third openings 150a, and the second bonding pad 200b may contact the fourth openings 150b. It may be in contact with the second electrode 150 through.

The first and second bonding pads 200a and 200b include the non-conductive region 220 positioned in the solder ball contactable region 210, as described in the above embodiments. Each of the first and second bonding pads 200a and 200b may include a portion disposed side by side on one side of the light emitting device, and at least one protrusion 240 protruding from the portion. For example, the first bonding pad 200a may include a portion generally disposed side by side on the first side surface 100a of the light emitting device and three protrusions 240 protruding from the portion. The non-conductive area 220 of the first bonding pad 200a may be located between the three protrusions 240. Similarly, the second bonding pad 200b may include a portion generally disposed side by side on the third side surface 100c of the light emitting device and three protrusions 240 protruding from the portion. The non-conductive area 220 of the second bonding pad 200b may be located between the three protrusions 240. Through the non-conductive region 220, it is possible to effectively prevent voids generated during the soldering process.

The width t2 and the width t1 of the protrusions disposed side by side on one side of each of the first and second bonding pads 200a and 200b may be the same as or different from each other. However, the widths t1 and t2 may be 40 to 200 μm, as described in the above embodiments.

The first bonding pad 200a may contact the first conductive semiconductor layer 111 through the regions 110a, 110b and 110c where the first conductive semiconductor layer 111 is partially exposed. A portion of 140 may be at least partially covered. In particular, the first bonding pad 200a may be formed to cover a portion of the first electrode 140 positioned on the first hole 110a and the second hole 110b having a relatively large width. For example, the protrusions 240 of the first bonding pad 200a may be disposed corresponding to the positions where the first holes 110a and the second holes 110b are formed.

Due to heat, stress, etc. generated during the soldering process, the first conductivity-type semiconductor layer 111 and the first electrode are formed through regions 110a, 110b, and 110c where the first conductivity-type semiconductor layer 111 is partially exposed. Stress and strain may be applied to the interface 140 contacts. Due to such stress and strain, a problem may occur in which the first electrode 140 is separated from the first conductive semiconductor layer 111. In this case, the forward voltage Vf of the light emitting device is increased or current dispersion is smooth. A phenomenon that cannot be achieved may occur. In this case, a decrease in reliability may occur due to a decrease in electrical and optical characteristics of the light emitting device.

According to the present exemplary embodiment, a portion of the first electrode 140 positioned on the first hole 110a and the second hole 110b is covered by the first bonding pad 200a to thereby cover the first electrode 140. ) Can be fixed more securely. Accordingly, it is possible to effectively prevent the first electrode 140 from being peeled from the first conductivity type semiconductor layer 111 in the soldering process. In addition, since the first hole 110a and the second hole 110b have a relatively larger width than the third hole 110c, the current injection efficiency through the first hole 110a and the second hole 110b. When this decreases, the deterioration of characteristics of the light emitting device may be further intensified. According to the present embodiment, by covering the portion of the first electrode 140 positioned on the first hole 110a and the second hole 110b with the first bonding pad 200a, reliability of the light emitting device more effectively. Can improve.

9 to 14, the first bonding pad 200a and the second bonding pad 200b may be formed to be generally symmetrical. However, the present invention is not limited thereto, and the protrusions 240 of the first and second bonding pads 200a and 200b may be variously modified. For example, referring to FIGS. 15 and 16, the protrusions 240 of the first bonding pad 200a may be formed on the first and second holes 110a and 110b. Accordingly, the first bonding pad 200a may include three protrusions 240 protruding in the direction toward the second bonding pad 200b, and the non-conductive area 220 may be disposed between the three protrusions 240. Is placed. In response, the second bonding pad 200b may include protrusions 240 protruding in a direction toward the non-conductive area 220 of the first bonding pad 200a. In the present embodiment, by changing the arrangement of the protrusions 240, the passage through which the void is discharged to the outside in the reflow process can be changed.

The first and second bonding pads 200a and 200b of the present exemplary embodiment are not limited thereto and may be variously changed as described in the embodiments of FIGS. 1 to 8. In this case, the first and second bonding pads 200a and 200b are formed to cover the first hole 110a and the second hole 110b, thereby similarly obtaining a reliability improvement effect of the light emitting device according to the present embodiment. have.

17 is an exploded perspective view illustrating an example in which a light emitting device according to an embodiment of the present invention is applied to a lighting device.

Referring to FIG. 17, the lighting apparatus according to the present embodiment includes a diffusion cover 1010, a light emitting device module 1020, and a body portion 1030. The body portion 1030 may accommodate the light emitting device module 1020, and the diffusion cover 1010 may be disposed on the body portion 1030 to cover the upper portion of the light emitting device module 1020.

The body portion 1030 is not limited as long as it can receive and support the light emitting device module 1020 and supply electric power to the light emitting device module 1020. For example, as shown, the body portion 1030 may include a body case 1031, a power supply device 1033, a power case 1035, and a power connection portion 1037.

The power supply device 1033 is accommodated in the power case 1035 and electrically connected to the light emitting device module 1020, and may include at least one IC chip. The IC chip may adjust, convert, or control the characteristics of the power supplied to the light emitting device module 1020. The power case 1035 may receive and support the power supply 1033, and the power case 1035 to which the power supply 1033 is fixed may be located inside the body case 1031. . The power connection unit 115 may be disposed at a lower end of the power case 1035 and may be coupled to the power case 1035. Accordingly, the power connection unit 1037 may be electrically connected to the power supply device 1033 inside the power case 1035 to serve as a path through which external power may be supplied to the power supply device 1033.

The light emitting device module 1020 includes a substrate 1023 and a light emitting device 1021 disposed on the substrate 1023. The light emitting device module 1020 may be disposed on the body case 1031 and electrically connected to the power supply device 1033.

The substrate 1023 is not limited as long as it can support the light emitting device 1021. For example, the substrate 1023 may be a printed circuit board including wiring. The substrate 1023 may have a shape corresponding to the fixing portion of the upper portion of the body case 1031 so as to be stably fixed to the body case 1031. The light emitting device 1021 may include at least one of the light emitting devices according to the embodiments of the present invention described above.

The diffusion cover 1010 may be disposed on the light emitting device 1021, and may be fixed to the body case 1031 to cover the light emitting device 1021. The diffusion cover 1010 may have a translucent material and may adjust the directivity of the lighting device by adjusting the shape and the light transmittance of the diffusion cover 1010. Therefore, the diffusion cover 1010 may be modified in various forms according to the purpose of use of the lighting device and the application aspect.

18 is a cross-sectional view illustrating an example in which a light emitting device according to an embodiment of the present invention is applied to a display device.

The display device according to the present exemplary embodiment includes a display panel 2110, a backlight unit providing light to the display panel 2110, and a panel guide supporting a lower edge of the display panel 2110.

The display panel 2110 is not particularly limited and may be, for example, a liquid crystal display panel including a liquid crystal layer. A gate driving PCB for supplying a driving signal to the gate line may be further located at the edge of the display panel 2110. Here, the gate driving PCB is not configured in a separate PCB, but may be formed on the thin film transistor substrate.

The backlight unit includes a light source module including at least one substrate and a plurality of light emitting devices 2160. In addition, the backlight unit may further include a bottom cover 2180, a reflective sheet 2170, a diffusion plate 2131, and optical sheets 2130.

The bottom cover 2180 may be opened upward to accommodate the substrate, the light emitting device 2160, the reflective sheet 2170, the diffusion plate 2131, and the optical sheets 2130. In addition, the bottom cover 2180 may be combined with the panel guide. The substrate may be disposed under the reflective sheet 2170 and be surrounded by the reflective sheet 2170. However, the present invention is not limited thereto, and when the reflective material is coated on the surface, the reflective material may be positioned on the reflective sheet 2170. In addition, a plurality of substrates may be formed, and the plurality of substrates may be arranged in a side-by-side arrangement, but is not limited thereto and may be formed of a single substrate.

The light emitting device 2160 may include at least one of the light emitting devices according to the embodiments of the present invention described above. The light emitting devices 2160 may be regularly arranged in a predetermined pattern on the substrate. In addition, a lens 2210 may be disposed on each light emitting device 2160 to improve uniformity of light emitted from the plurality of light emitting devices 2160.

The diffusion plate 2131 and the optical sheets 2130 are positioned on the light emitting device 2160. Light emitted from the light emitting device 2160 may be supplied to the display panel 2110 in the form of a surface light source through the diffusion plate 2131 and the optical sheets 2130.

As such, the light emitting device according to the embodiments of the present invention may be applied to the direct type display device as the present embodiment.

19 is a cross-sectional view illustrating an example in which a light emitting device according to an embodiment is applied to a display device.

The display device including the backlight unit according to the present exemplary embodiment includes a display panel 3210 on which an image is displayed and a backlight unit disposed on a rear surface of the display panel 3210 to irradiate light. In addition, the display apparatus includes a frame 240 that supports the display panel 3210 and accommodates the backlight unit, and covers 3240 and 3280 that surround the display panel 3210.

The display panel 3210 is not particularly limited and may be, for example, a liquid crystal display panel including a liquid crystal layer. A gate driving PCB for supplying a driving signal to the gate line may be further located at an edge of the display panel 3210. Here, the gate driving PCB is not configured in a separate PCB, but may be formed on the thin film transistor substrate. The display panel 3210 may be fixed by covers 3240 and 3280 positioned at upper and lower portions thereof, and the cover 3280 positioned at lower portions thereof may be coupled to the backlight unit.

The backlight unit for providing light to the display panel 3210 may include a lower cover 3270 having a portion of an upper surface thereof, a light source module disposed on one side of the lower cover 3270, and positioned in parallel with the light source module to provide point light. And a light guide plate 3250 for converting to surface light. In addition, the backlight unit according to the present exemplary embodiment is disposed on the light guide plate 3250 and is disposed below the light guide plate 3250 and the optical sheets 3230 for diffusing and condensing light. The display apparatus may further include a reflective sheet 3260 reflecting in the direction of the display panel 3210.

The light source module includes a substrate 3220 and a plurality of light emitting devices 3110 spaced apart from each other by a predetermined interval on one surface of the substrate 3220. The substrate 3220 is not limited as long as it supports the light emitting device 3110 and is electrically connected to the light emitting device 3110. For example, the substrate 3220 may be a printed circuit board. The light emitting device 3110 may include at least one light emitting device according to the embodiments of the present invention described above. Light emitted from the light source module is incident to the light guide plate 3250 and is supplied to the display panel 3210 through the optical sheets 3230. Through the light guide plate 3250 and the optical sheets 3230, the point light sources emitted from the light emitting devices 3110 may be transformed into surface light sources.

As such, the light emitting device according to the embodiments of the present invention may be applied to the edge type display device as the present embodiment.

20 is a cross-sectional view illustrating an example in which a light emitting device according to an embodiment of the present invention is applied to a head lamp.

Referring to FIG. 20, the head lamp includes a lamp body 4070, a substrate 4020, a light emitting device 4010, and a cover lens 4050. Furthermore, the head lamp may further include a heat dissipation unit 4030, a support rack 4060, and a connection member 4040.

The substrate 4020 is fixed by the support rack 4060 and spaced apart from the lamp body 4070. The substrate 4020 is not limited as long as it is a substrate capable of supporting the light emitting device 4010. For example, the substrate 4020 may be a substrate having a conductive pattern such as a printed circuit board. The light emitting device 4010 is positioned on the substrate 4020 and may be supported and fixed by the substrate 4020. In addition, the light emitting device 4010 may be electrically connected to an external power source through the conductive pattern of the substrate 4020. In addition, the light emitting device 4010 may include at least one light emitting device according to the embodiments of the present invention described above.

The cover lens 4050 is positioned on a path along which light emitted from the light emitting element 4010 travels. For example, as shown, the cover lens 4050 may be disposed spaced apart from the light emitting element 4010 by the connecting member 4040, and may be disposed in a direction to provide light emitted from the light emitting element 4010. Can be. By the cover lens 4050, the direction angle and / or color of the light emitted from the head lamp to the outside may be adjusted. Meanwhile, the connection member 4040 may fix the cover lens 4050 with the substrate 4020 and may be disposed to surround the light emitting device 4010 to serve as a light guide for providing the light emitting path 4045. In this case, the connection member 4040 may be formed of a light reflective material or coated with a light reflective material. Meanwhile, the heat dissipation unit 4030 may include a heat dissipation fin 4031 and / or a heat dissipation fan 4033, and emits heat generated when the light emitting device 4010 is driven to the outside.

As such, the light emitting device according to the embodiments of the present invention may be applied to the head lamp, in particular, a vehicle head lamp as in the present embodiment.

Although the above has been described with reference to the embodiments of the present invention, various changes and modifications can be made at the level of those skilled in the art. Such changes and modifications can be said to belong to the present invention without departing from the scope of the technical idea provided by the present invention. Therefore, the scope of the present invention will be determined by the claims described below.

Claims (23)

In the light emitting device in which the bonding pad is soldered on the mounting substrate, The bonding pad is connected to the first electrode and the second electrode electrically connected to the first conductivity type semiconductor layer and the second conductivity type semiconductor layer by connecting electrodes, respectively. Two or more linear bonding pads are formed in the solder ball contact area. At least two of the two or more linear bonding pads face each other, and a non-conductive area is present between the two bonding pads facing each other. The method of claim 1, At least two of the two or more linear bonding pads are spaced apart from each other. The method of claim 1, At least two of the two or more linear bonding pads are connected to each other. The method of claim 1, The two or more linear bonding pads are formed n (n≥2), and the light emitting device, characterized in that connected to each other, including at least n-1 or more. The method of claim 1, The linear bonding pad has a width of 200 μm or less. The method of claim 1, The linear bonding pad has a width of 40 μm or more. The method of claim 1, And the area of the linear bonding pad is 40% or more of the solder ball contactable area. The method of claim 1, The connection electrode includes a first connection electrode electrically connecting the bonding pad and the first electrode and a second connection electrode electrically connecting the bonding pad and the second electrode. The method of claim 8, The first connecting electrode is formed in the opening of the upper insulating layer positioned on the first electrode. The method of claim 8, And the second connection electrode is formed in an opening of a lower insulating layer on the second electrode and an upper insulating layer on the first electrode. The method of claim 1, The bonding pad includes a first bonding pad and a second bonding pad spaced apart from each other, The light emitting device includes a first conductive semiconductor layer electrically connected to the first bonding pad, a second conductive semiconductor layer electrically connected to the second bonding pad, the first conductive semiconductor layer and the first conductive layer. 2 includes an active layer interposed between the conductive semiconductor layer, Light emitting device, characterized in that the active layer is separated into two or more. In the light emitting device in which the bonding pad is soldered on the mounting substrate, The bonding pad is connected to the first electrode and the second electrode electrically connected to the first conductivity type semiconductor layer and the second conductivity type semiconductor layer by connecting electrodes, respectively. A bonding pad is formed in a part of the solder ball contactable area, and a non-conductive pattern for void escape is formed in the rest of the solder ball contactable area. The method of claim 12, And the non-conductive pattern is formed in the direction of the edge of the solder ball contactable region within 200 μm at any point in the bonding pad electrode. The method of claim 13, The non-conductive pattern is a light emitting device, characterized in that the tapered shape that increases toward the edge portion of the solder ball contactable region. The method of claim 12, The area of the bonding pad is light emitting device, characterized in that more than 40% of the solder ball contact area. The method of claim 12, The connection electrode includes a first connection electrode electrically connecting the bonding pad and the first electrode and a second connection electrode electrically connecting the bonding pad and the second electrode. The method of claim 16, The first connecting electrode is formed in the opening of the upper insulating layer positioned on the first electrode. The method of claim 16, And the second connection electrode is formed in an opening of a lower insulating layer on the second electrode and an upper insulating layer on the first electrode. The method of claim 12, The bonding pad includes a first bonding pad and a second bonding pad spaced apart from each other, The light emitting device includes a first conductive semiconductor layer electrically connected to the first bonding pad, a second conductive semiconductor layer electrically connected to the second bonding pad, the first conductive semiconductor layer and the first conductive layer. An active layer interposed between the two conductive semiconductor layers, Light emitting device, characterized in that the active layer is separated into two or more. The method of claim 1, An active layer disposed between the first conductive semiconductor layer, the second conductive semiconductor layer, and the first and second conductive semiconductor layers, and penetrating through the second conductive semiconductor layer and the active layer; The semiconductor device may further include a nitride based semiconductor laminate including a region exposing the first conductive semiconductor layer. The region exposing the first conductivity type semiconductor layer includes holes, The first electrode is in contact with the first conductivity type semiconductor layer through the holes, A portion of the first electrode positioned on at least some of the holes is covered by the bonding pads. The method of claim 20, The holes, A first hole; A second hole spaced apart from the first hole; And A third hole connected to the second hole and extending from the second hole, The width of the third hole is smaller than the width of the first hole and the second hole. The method of claim 21, The bonding pad includes a first bonding pad connected to the first electrode, and a second bonding pad connected to the second electrode. The first bonding pad covers a portion of the first electrode positioned on the first hole and the second hole. The method of claim 22, The third hole extends in a direction from the second hole toward the second bonding pad, At least a portion of the third hole is a light emitting device positioned below the first and second bonding pads.

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