KR101221643B1 - Flip chip Light-emitting device and Method of manufacturing the same - Google Patents

Abstract

The present invention provides an n-type semiconductor layer on one surface of a base substrate, a p-type semiconductor layer formed on a portion of the n-type semiconductor layer, a light emitting cell block including a light emitting cell including an ohmic transmission layer, and the light emitting cell block is a flip chip. It includes a sub-mount substrate to be bonded, the sub-mount substrate provides a light emitting device and a method for manufacturing the same, characterized in that it comprises a reflective layer on the upper surface is flip-chip bonded.
The light emitting device and the method of manufacturing the same according to the present invention form an ohmic transmission layer on the p-type semiconductor layer and a reflection layer on the sub-mount substrate, thereby preventing the absorption of light and increasing the reflectance to improve the luminous efficiency and the light output. Properties can be improved.

Description

Flip chip light emitting device and method for manufacturing the same {Flip chip Light-emitting device and Method of manufacturing the same}

The present invention relates to a light emitting device and a method of manufacturing the same, and more particularly, to a light emitting device for improving the luminous efficiency and brightness in a light emitting device having a flip-chip structure and a manufacturing method thereof.

A light emitting diode (LED) refers to a device that makes a small number of carriers (electrons or holes) injected using a pn junction structure of a semiconductor and emits a predetermined light by recombination thereof. GaAs, AlGaAs, GaN Various colors may be realized by configuring a light emitting source by changing a compound semiconductor material such as InGaN, AlGaInP, or the like.

Such a light emitting device has a smaller power consumption and a longer life than conventional light bulbs or fluorescent lamps, can be installed in a narrow space, and exhibits strong vibration resistance. These light emitting devices are used as display devices and backlights, and because they have excellent characteristics in terms of power consumption reduction and durability, they are expected to be widely applied to general lighting, large LCD-TV backlights, automotive headlights, and general lighting. For this purpose, the light emission efficiency of the light emitting device needs to be improved, the heat dissipation problem must be solved, and the high brightness and high power of the light emitting device must be achieved.

In order to solve this problem, interest in semiconductor light emitting devices having a flip-chip structure has recently increased. The light emitting device of the flip chip structure emits light through the sapphire substrate instead of the p-type semiconductor layer to improve current spreading of the p-type semiconductor layer by using a thick p-type electrode and greatly reduce thermal resistance due to heat dissipation through the sub-mount substrate. You can.

Since the light emitting device having a flip chip structure has to reflect light emitted from the active layer to the p-type semiconductor layer and emit light toward the sapphire substrate, the formation of the reflective layer is an essential element, and the contact resistance is improved to improve driving voltage characteristics. Efforts to increase reflectance are needed to improve light extraction efficiency.

Accordingly, many studies on the reflective layer have been performed. In Korean Patent No.0506741, a nitride semiconductor light emitting device for flip chip having improved adhesion and current spreading efficiency and contact resistance by providing three layers of adhesion securing layer, reflective electrode layer, and cap layer has improved brightness and driving voltage characteristics. It is starting. In addition, the Republic of Korea Patent Publication No. 2005-0068402 includes a high reflection coating layer formed by alternately forming a pair of the first coating layer and the second coating layer of a predetermined refractive index in a predetermined region of the p-type cladding layer to lower the contact resistance and reflectance An increased light emitting device is disclosed.

In the patent, generally, as shown in FIG. 1, a reflective layer is formed on a p-type semiconductor layer and a flip chip structure is formed. That is, the n-type semiconductor layer 5, the active layer 6, and the p-type semiconductor layer 7 are sequentially formed on the predetermined substrate 1. A portion of the p-type semiconductor layer 7 and the active layer 6 are etched to expose the n-type semiconductor layer 5, and then an ohmic reflective layer 8 is formed on the p-type semiconductor layer 7 to form a light emitting cell. Manufacture. In addition, a separate sub-mount substrate 2 is prepared to form the first and second electrodes 3 and 4, the p-type solder 9 is formed on the first electrode 3, and the second electrode 4 is formed. ), N-type solder 10 is formed. Thereafter, the light emitting cell is bonded to the sub-mount substrate 2, and the p electrode of the light emitting cell is bonded to the p-type solder 9 and the n electrode to the n-type solder 10. A light emitting device is manufactured by forming a molding part (not shown) which encapsulates a substrate on which a light emitting cell is bonded.

However, in the semiconductor light emitting device having such a structure, a large amount of photons generated in the light emitting layer is absorbed and dissipated in the space inside the flip chip. That is, since the active layer is reflected by the reflective layer on the p-type semiconductor layer and absorbs and disappears again through the semiconductor layer, it does not easily escape to the outside of the light emitting device and has a disadvantage in low light output.

Korean Patent Publication No. 10-2005-0068402 (published Jul. 5, 2005)

Disclosure of Invention The present invention has been made to solve the above-mentioned problem, and has a high brightness and luminous efficiency by preventing light absorption and smooth reflection of light, and efficiently dissipates generated heat, thereby providing a light emitting device having a flip-chip structure and improved light output characteristics and reproducibility thereof. It is an object to provide a manufacturing method.

In order to achieve the above object, the present invention provides a light emitting cell block on which a light emitting cell including an n-type semiconductor layer, a p-type semiconductor layer formed on a portion of the n-type semiconductor layer, and an ohmic transmission layer is formed on one surface of the base substrate. And a sub-mount substrate on which the light-emitting cell block is flip chip bonded, and the sub-mount substrate includes a reflective layer on an upper surface of the flip chip bonding.

A plurality of light emitting cells spaced apart from each other may be formed on one surface of the base substrate, and an n-type semiconductor layer of the one light emitting cell and a p-type semiconductor layer of another light emitting cell adjacent thereto may be connected, and the n-type of the one light emitting cell may be connected. The semiconductor device may further include a wiring for connecting the semiconductor layer and the p-type semiconductor layer of another light emitting cell adjacent thereto.

The reflective layer may be Al, Ag, or an alloy thereof, and may further include a dielectric film on the reflective layer. The ohmic transmission layer may be an alloy of two or more layers including indium tin oxide (ITO) or Ni.

The base substrate may include irregularities, and may further include a transmissive layer including irregularities on the other surface of the base substrate.

According to the present invention, a light emitting cell block is formed by sequentially forming an n-type semiconductor layer, a p-type semiconductor layer, and an ohmic transmission layer on an upper surface of a base substrate, providing a sub-mount substrate on which a reflective layer is formed, and the light emitting cell block. It provides a method of manufacturing a light emitting device comprising flip chip bonding to the sub-mount substrate.

The preparing of the light emitting cell block may include forming a plurality of light emitting cells by removing a portion of the n-type semiconductor layer, the p-type semiconductor layer, and the ohmic transmission layer, and the n-type semiconductor of one light emitting cell through a bridge wiring. The method may further include connecting the p-type semiconductor layer of another light emitting cell adjacent to the layer. The bridge wiring may connect an n-type semiconductor layer of one light emitting cell to a p-type semiconductor layer of another adjacent light emitting cell through a bridge process or a step cover process.

Prior to preparing the light emitting cell block, the method may further include forming irregularities on the base substrate. Alternatively, the method may further include forming a transmission layer including irregularities on the lower surface of the base substrate.

The light emitting device and the method of manufacturing the same according to the present invention implement a light emitting device in which a plurality of light emitting cells are arranged in a flip chip structure, thereby reducing the thermal burden of the light emitting device by heat emission through a sub-mount substrate, and a separate control device. There is an advantage that can be used as a general lighting device without.

Also, in such a light emitting device, by forming an ohmic transmissive layer on a p-type semiconductor layer and a reflective layer on a sub-mount substrate, it is possible to prevent light absorption and improve reflectance to improve luminous efficiency and improve light output characteristics. Can be.

1 is a cross-sectional view showing a light emitting device having a conventional flip chip structure.
2 is a sectional view showing a first embodiment according to the present invention;
3A to 3F are cross-sectional views illustrating a manufacturing process of the first embodiment according to the present invention.
4A to 4D are cross-sectional views for explaining a manufacturing process of the second embodiment according to the present invention.
5 is a sectional view showing a third embodiment according to the present invention;
6 is a sectional view showing a fourth embodiment according to the present invention;

Hereinafter, a light emitting device and a method of manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the present embodiments are intended to complete the disclosure of the present invention and to those skilled in the art to fully understand the scope of the invention. It is provided to inform you.

In the semiconductor light emitting device having a flip chip structure, an ohmic transmission layer is formed on a p-type semiconductor layer instead of a conventional reflection layer, and a reflection layer is formed on a submount substrate so that light generated in the light emitting layer passes through the semiconductor light emitting device. By causing reflection in the sub-mount substrate, light is emitted without absorbing light, thereby improving light efficiency.

2 is a cross-sectional view showing a first embodiment according to the present invention.

Referring to the drawings, a light emitting layer sequentially formed on the base substrate 20, that is, the n-type semiconductor layer 30, the active layer 40 and the p-type semiconductor layer 50, and includes the metal bumps 70, 75 And a sub-mount substrate that is flip chip bonded to the base substrate 20 on which the light emitting layer is formed. The surface on which the metal bumps 70 of the light emitting layer are bonded, that is, the upper surface of the p-type semiconductor layer 50 includes an ohmic transmission layer 60 that transmits light and increases a current injection area. The sub-mount substrate may be bonded to a reflective layer 220 reflecting light emitted from the light emitting layer on a separate substrate 210, and a p-type semiconductor layer 50 and an n-type semiconductor layer 30 of the light emitting layer, respectively. and a p-type bonding pad 240 and an n-type bonding pad 245. When the reflective layer 220 is made of metal, the reflective layer 220 further includes a dielectric film 230 that serves to insulate the reflective layer 220.

The light emitting device of the present invention can reduce the thermal burden of the light emitting device through heat dissipation through the sub-mount substrate, the light generated in the light emitting layer is transmitted through the ohmic transmission layer formed on the p-type semiconductor layer and the sub-mount substrate By reflecting due to the reflective layer of the light exits to the outside without absorbing light through the semiconductor layer it is possible to obtain improved luminous efficiency.

A plurality of light emitting devices can be fabricated on a substrate and later cut individually to use a single cell as a light emitting device, and as described below, a plurality of light emitting cells can be connected in series, in parallel or in parallel to each other at the wafer level. One light emitting device may be manufactured. Such a light emitting device can be connected to a plurality of light emitting cells in series, parallel or series-parallel to reduce the size of the device, to be driven at a suitable voltage and current can be used for lighting and can also be driven in AC power. This will be described later in detail.

3A to 3F are cross-sectional views illustrating an example of a manufacturing process of the first embodiment according to the present invention.

Referring to FIG. 3A, an emission layer, that is, an n-type semiconductor layer 30, an active layer 40, and a p-type semiconductor layer 50 is sequentially formed on the base substrate 20.

The base substrate 20 refers to a general wafer for manufacturing a light emitting device, and a transparent substrate such as Al ₂ O ₃ , ZnO, LiAl ₂ O _3, or the like is used. In this embodiment, a sapphire substrate is used. Before the n-type semiconductor layer 30 is formed on the base substrate 20, a buffer layer (not shown) including AlN or GaN may be formed to reduce the lattice mismatch with the sapphire substrate.

The n-type semiconductor layer 30 is a layer in which electrons are generated, preferably using gallium nitride (GaN) implanted with n-type impurities, and the material layer having various semiconductor properties is not limited thereto. In this embodiment, an n-type semiconductor layer 30 including n-type Al _x Ga _{1 - x} N (0 ≦ _x ≦ ₁ ) is formed. In addition, the p-type semiconductor layer 50 is a layer in which holes are generated, preferably using gallium nitride (GaN) implanted with p-type impurities, and not limited thereto, and may be a material layer having various semiconductor properties. In this embodiment, a p-type semiconductor layer 50 including p-type Al _x Ga _{1 - x} N (0 ≦ _x ≦ ₁ ) is formed. In addition, InGaN may be used as the semiconductor layer. The n-type semiconductor layer 30 and the p-type semiconductor layer 50 may be formed of a multilayer film.

The active layer 40 has a predetermined band gap and is a region in which quantum wells are made to recombine electrons and holes, and may include InGaN. According to the type of material constituting the active layer 40, the emission wavelength generated by the combination of electrons and holes is changed. Therefore, it is preferable to adjust the semiconductor material contained in the active layer 40 according to the target wavelength.

The above-described material layers may include metal organic chemical vapor deposition (MOCVD), chemical vapor deposition (CVD), plasma chemical vapor deposition (PCVD), molecular beam growth (MBE), and molecular beam growth (MBE). It is formed through various deposition and growth methods including beam epitaxy) and hydride vapor phase epitaxy (HVPE).

Thereafter, as shown in FIG. 3B, portions of the p-type semiconductor layer 50, the active layer 40, and the n-type semiconductor layer 30 are removed to separate the light emitting cells. To this end, a predetermined mask pattern (not shown) is formed on the p-type semiconductor layer 50, and then the p-type semiconductor layer 50, the active layer 40, and the n-type semiconductor layer in the region exposed by the mask pattern. The 30 is etched to electrically separate the plurality of light emitting cells.

As shown in FIG. 3C, a portion of the n-type semiconductor layer 30 is exposed by removing a portion of the p-type semiconductor layer 50 and the active layer 40 through a predetermined etching process. After the predetermined etching mask pattern is formed on the p-type semiconductor layer 50, a dry / wet etching process is performed to remove the p-type semiconductor layer 50 and the active layer 40 to form the n-type semiconductor layer 30. Expose

As shown in FIG. 3D, an ohmic transmission layer 60 is formed on the p-type semiconductor layer 50 to reduce the resistance of the p-type semiconductor layer 50 and improve light transmittance. As the ohmic transmission layer 60, two or more alloy layers including indium tin oxide (ITO) or Ni are used. In addition, a separate ohmic metal layer including Cr and Au may be further formed on the exposed n-type semiconductor layer 30 to smoothly supply current.

In addition, a p-type metal bump 70 is formed on the ohmic transmission layer 60 on the p-type semiconductor layer 30, and an n-type metal bump 75 is formed on the exposed n-type semiconductor layer 30. . To this end, the photoresist is applied over the entire structure, and then a photolithography process using a predetermined mask is performed to expose a portion of the ohmic transmission layer 60 and the n-type semiconductor layer 30. Form a). After depositing a metal film on the entire structure, the metal film formed on the ohmic transmission layer 60 exposed by the photosensitive film pattern, the metal film of the remaining region except the metal film formed on the n-type semiconductor layer 30 and The photosensitive film pattern is removed. As a result, the p-type metal bump 70 is formed on the ohmic transmission layer 60, and the n-type metal bump 75 is formed on the n-type semiconductor layer 30. As the p-type and n-type metal bumps 70 and 75, at least one of Pb, Sn, Au, Ge, Cu, Bi, Cd, Zn, Ag, Ni, and Ti may be used, and an alloy thereof may be used. have.

As a result, the light emitting cell block 100 in which the plurality of light emitting cells is formed is formed. The manufacturing process of the light emitting cell block 100 is not limited to the above-described method, and various modifications and various material films may be further added. That is, the ohmic transmission layer 60 may be formed on the p-type semiconductor layer 50, and then etching may be performed to separate the light emitting cells. In addition, the n-type semiconductor layer 30 may be exposed first, and then a part of the exposed n-type semiconductor layer 30 may be removed to separate the light emitting cells.

Next, a separate sub-mount substrate 200 to be bonded with the light emitting cell block 100 is prepared.

Referring to FIG. 3E, the sub-mount substrate 200 includes a substrate 210, a reflective layer 220 formed on the surface of the substrate 210, a dielectric film 230, and one light emission of the light emitting cell block 100. And a plurality of electrode layers 250 connecting the n-type semiconductor layer 30 of the cell to the p-type semiconductor layer 50 of another light emitting cell. The apparatus may further include a p-type bonding pad 240 formed at one edge and an n-type bonding pad 245 formed at the other edge.

In this case, SiC, Si, Ge, SiGe, AlN, metal, or the like having excellent thermal conductivity is used as the substrate 210. In this embodiment, AlN having excellent thermal conductivity and insulating properties is used. Of course, the present invention is not limited thereto, and a metallic material having high thermal conductivity and excellent electrical conductivity may be used.

The reflective layer 220 on the surface of the substrate 210 uses Al, Ag, or an alloy of these metals. An insulating film or a dielectric film is formed on the reflective layer 220 to provide sufficient insulation. SiO ₂ , MgO and SiN, or an insulating material may be used as the dielectric film 230. In addition, the electrode layer 250, the n-type bonding pad 245, and the p-type bonding pad 240 use a metal having excellent electrical conductivity. It is formed by a screen printing method or a deposition process using a predetermined mask pattern.

Thereafter, the light emitting cell block 100 and the sub-mount substrate 200 are flip-chip bonded to manufacture a light emitting device. That is, FIG. 3F illustrates that the light emitting cell block 100 and the sub-mount substrate 200 are bonded. The light emitting device of the present invention is bonded through the metal bumps 70 and 75, but the light emitting cell block ( The n-type semiconductor layer 30 of another light emitting cell adjacent to the p-type semiconductor layer 50 of one light emitting cell of 100 is electrically connected through the metal bumps 70 and 75 and the electrode layer 250 of the submount substrate 200. Bond to be connected. The p-type metal bump 70 located at one edge of the light emitting cell block 100 is connected to the p-type bonding pad 240 of the sub-mount substrate 200, and the n-type metal bump 75 located at the other edge of the light emitting cell block 100 is connected to the sub type. The n-type bonding pad 245 of the mount substrate 200 is connected.

At this time, the bonding may be performed using heat or ultrasonic waves, or simultaneously using heat and ultrasonic waves. The connection between the metal bumps 70 and 75 and the lower bonding pads 240 and 245 is bonded through various bonding methods.

In addition, the n-type and p-type metal bumps 70 and 75 may not be formed on the light emitting cell, and the metal bumps 70 and 75 may be formed on the sub-mount substrate.

The manufacturing process of the light emitting device of the present invention described above is not limited thereto, and various processes and manufacturing methods may be changed or added according to the characteristics of the device and the convenience of the process.

As a result, a light emitting device in which a plurality of light emitting cells in a flip chip form is arranged on a sub-mount substrate may be manufactured. The light emitting cells may be variously connected in series, in parallel, or in parallel and according to a desired purpose. The light emitting device of the present invention transmits the light generated in the light emitting layer through the ohmic transmission layer on the p-type semiconductor layer and reflects it by the reflective layer on the sub-mount substrate, thereby preventing the absorption of the light and smoothly reflecting the light to achieve high luminance and luminous efficiency. You can get it.

In the present embodiment, the n-type semiconductor layer and the p-type semiconductor layer of adjacent light emitting cells are electrically connected to each other using metal bumps during flip chip bonding of the light emitting cell block and the sub-mount substrate. However, the present invention is not limited thereto, and the bridge wiring electrically connecting the n-type semiconductor layer and the p-type semiconductor layer of adjacent light emitting cells through a bridge process or a step cover during manufacturing of the light emitting cell block. After the formation, the chip may be flip-chip bonded to the sub-mount substrate. Detailed description thereof will be described later.

4A to 4D are cross-sectional views for describing the second embodiment.

Referring to FIG. 4A, a plurality of light emitting cells in which an n-type semiconductor layer 30, an active layer 40, and a p-type semiconductor layer 50 are sequentially formed are formed on a base substrate 20. An ohmic transmissive layer 60 including two or more alloy layers including indium tin oxide (ITO) or Ni is formed on the p-type semiconductor layer 50. This is the same as the case of the first embodiment described above, and overlapping description is omitted.

Thereafter, the n-type semiconductor layer 30 and the p-type semiconductor layer 50 between adjacent light emitting cells are connected through a predetermined wiring forming process. That is, the exposed n-type semiconductor layer 30 of one light emitting cell and the p-type semiconductor layer 50 of another light emitting cell adjacent thereto are connected to the wiring 80. At this time, the conductive wiring 80 electrically connecting the n-type semiconductor layer 30 and the p-type semiconductor layer 50 of adjacent light emitting cells through a bridge process or a step cover process. To form.

The bridge process described above is also referred to as an air bridge process, by using a photo process between the chips to be connected to each other by using a photo process to form a photoresist pattern, and then forming a material such as metal on the first thin film by a method such as vacuum deposition, Again, a conductive material containing gold is applied to a predetermined thickness by a method such as electroplating, electroplating or metal deposition. Subsequently, when the photoresist pattern is removed with a solution such as solvent, the lower portion of the conductive material is removed and only the bridge-shaped conductive material is formed in the space.

In addition, the step cover process uses a photo process between the chips to be connected to each other using a photo process, and develops, leaving only the portions to be connected to each other, and covering the other portions with a photoresist pattern, and on top of it by electroplating, electroless plating or metal deposition. Applying a conductive material containing a predetermined thickness. Subsequently, when the photoresist pattern is removed with a solution such as a solvent, all portions other than the conductive material are covered and only the covered portions remain to electrically connect the chips to be connected.

As the wiring 80, all materials having conductivity as well as metal may be used. For example, it can be formed from Au, Ag, Ni, Cr, Pt, Pd, Ti, W, Ta or an alloy thereof.

Subsequently, a plurality of metal bumps 70 and 75 are formed on the light emitting cell, and the p-type semiconductor layer 50 of the light emitting cell positioned at one edge of the light emitting cell block 100 is positioned on the other side of the light emitting cell. The p-type metal bumps 70 and the n-type metal bumps 75 are formed on the n-type semiconductor layer 30, respectively.

As a result, the light emitting cell block 100 in which a plurality of light emitting cells are electrically connected by the conductive wiring 80 is formed.

Next, a sub-mount substrate 200 for a light emitting element having a flip chip structure of the present invention is provided.

Referring to FIG. 4C, the sub-mount substrate 200 includes a substrate 210, a reflective layer 220 formed on the surface of the substrate 210, a dielectric film 230, and a plurality of substrates formed on the dielectric film 230. Bonding layer 260. In addition, the semiconductor device further includes a p-type bonding pad 240 located at one edge and an n-type bonding pad 245 located at the other edge.

Thereafter, the light emitting cell block 100 and the sub-mount substrate 200 are flip-chip bonded to manufacture a light emitting device.

Referring to FIG. 4D, the light emitting device of the present invention flip-bonds the light emitting cell block 100 and the sub-mount substrate 200, and is bonded by metal bumps 70 and 75 formed on the light emitting cell. The p-type metal bump 70 located at one edge of the light emitting cell block 100 is connected to the p-type bonding pad 240 of the sub-mount substrate 200, and the n-type metal bump 75 located at the other edge of the light emitting cell block 100 is connected to the sub type. The n-type bonding pad 245 of the mount substrate 200 is connected. At this time, the bonding may be performed using heat or ultrasonic waves, or simultaneously using heat and ultrasonic waves.

The position of the metal bumps 70 and 75 is not limited thereto, and the metal bumps 70 and 75 may be formed in various positions in flip chip bonding as long as they do not interfere with the electric flow of the bridge wiring 80. In addition, the metal bumps 70 and 75 may not be formed in the light emitting cells in the light emitting cell block 100, and the metal bumps 70 and 75 may be formed on the sub-mount substrate 200.

Bonding of the light emitting cell block 100 and the sub-mount substrate 200 is not limited to the above-described method, and may be flip chip bonded by various bonding methods.

In the present embodiment, since the electrical connection is already completed through the bridge wiring 80 before the flip chip bonding, a separate pattern is required for the electrical connection during the flip chip bonding, or accordingly, an accurate alignment must be taken into consideration. There is an advantage to reduce the burden.

The manufacturing process of the light emitting device of the present invention described above is not limited thereto, and various processes and manufacturing methods may be changed or added according to the characteristics of the device and the convenience of the process.

As a result, a plurality of light emitting cells may be connected by conductive lines to fabricate a light emitting device flip-bonded on a sub-mount substrate. The light emitting cells may be variously connected in series, in parallel, or in parallel and according to a desired purpose. The light emitting device of the present invention transmits the light generated in the light emitting layer through the ohmic transmission layer on the p-type semiconductor layer and reflects it by the reflective layer on the sub-mount substrate, thereby preventing the absorption of the light and smoothly reflecting the light to achieve high luminance and luminous efficiency. You can get it.

The light emitting device of the present invention is not limited to the above description and various embodiments are possible.

Referring to the third embodiment shown in FIG. 5, the light emitting device includes a light emitting cell block in which a plurality of light emitting cells are arranged on a base substrate 25 including irregularities, and a sub-mount substrate on which the light emitting cell blocks are flip chip bonded. It includes.

This may be manufactured by first forming irregularities of a predetermined shape on the base substrate 25 through a predetermined etching process and then performing the same manufacturing process as described above.

The present embodiment has an advantage that higher luminance and luminous efficiency can be obtained because photons that have been reflected on a conventional flat surface exit outside without being reflected by various angles due to unevenness.

Alternatively, as in the fourth exemplary embodiment illustrated in FIG. 6, a light emitting device may be formed by forming a transmissive layer 90 including irregularities on a lower surface of the base substrate 20 of the light emitting cell block. This helps to extract the light more easily by changing the critical angle of the light as the surface irregularities as described above. Thus, a higher luminance and luminous efficiency can be obtained by increasing the probability that light generated in the light emitting layer is emitted to the outside of the light emitting device.

The third and fourth embodiments described above are not limited as shown and may be applied to other embodiments. For example, in the light emitting device of the present invention in which a plurality of light emitting cells are electrically connected by using a metal bump and an electrode layer as in the first embodiment shown in FIG. 3F, light emission efficiency is improved by forming irregularities on a base substrate. You can. In addition, the above-described embodiments may be applied in combination with each other.

20, 25: base substrate 30: n-type semiconductor layer
40: active layer 50: p-type semiconductor layer
60: ohmic transmission layer 70, 75: metal bump
80 wiring 90 transmission layer
100: light emitting cell block 200: sub-mount substrate
210: substrate 220: reflective layer
230: dielectric film 240, 245: bonding pad
250: electrode layer 260: bonding layer

Claims (10)

at least one light emitting cell block including an n-type semiconductor layer, an active layer formed on a portion of the n-type semiconductor layer, a p-type semiconductor layer formed on the active layer, and an ohmic transmission layer formed on the p-type semiconductor layer;
A sub-mount substrate on which the light emitting cell blocks are flip chip bonded; And
A p-type metal bump and an n-type metal bump for flip chip bonding the light emitting cell block to the sub-mount substrate,
A light emitting device comprising a reflective layer on an upper surface of the sub-mount substrate, the insulating layer or a dielectric film on the reflective layer.
The light emitting device according to claim 1, wherein the ohmic transmission layer is ITO.
The light emitting device according to claim 1, wherein the ohmic transmission layer is an alloy layer of two or more layers including Ni.
The light emitting device of claim 1, wherein the sub-mount substrate is any one of SiC, Si, Ge, SiGe, AlN, and metal.
The light emitting device of claim 4, wherein the sub-mount substrate has insulation.
The light emitting device of claim 4, wherein the sub-mount substrate is AlN.
The light emitting device according to claim 1, wherein the reflective layer is Al, Ag, or an alloy of these metals.
delete The light emitting device according to claim 7, further comprising an electrode layer provided on the insulating film or the dielectric film.
The light emitting device of claim 9, wherein the electrode layer electrically connects the p-type semiconductor layer of the light emitting cell block to the n-type semiconductor layer of another light emitting cell adjacent to the p-type semiconductor layer.

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