KR20060102657A - Luminous element having arrayed cells and method of manufacturing the same - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a light emitting device in which a plurality of cells are arrayed, the method comprising: providing a substrate on which a plurality of light emitting cells are formed; It provides a method of manufacturing a light emitting device comprising the step of connecting between the type semiconductor layer. Thus, the light emitting device can be connected between adjacent light emitting cells at the wafer level through a bridge wiring to reduce the size of the device, and a plurality of light emitting cells can be connected in series to provide a light emitting device that can operate even at high voltage for home use. The manufacturing process of the light emitting device can be simplified, and manufacturing cost and defect rate during manufacturing can be reduced by connecting the light emitting cells at the wafer level without a separate wire connection.

Light emitting element, many light emitting cell, bridge wiring, bridge process, photoresist pattern

Description

Luminous element having arrayed cells and method of manufacturing the same

1 is a cross-sectional view of a light emitting device combined with a plurality of cells according to the present invention.

2A to 2D are circuit diagrams for explaining a method for combining multiple cells according to the present invention.

3A to 3D are enlarged views of region A of FIG. 1, and are cross-sectional views illustrating a method of manufacturing a light emitting device according to a first embodiment of the present invention.

4A to 4C are cross-sectional views illustrating a method of manufacturing a light emitting device according to a second embodiment of the present invention.

5A and 5B are cross-sectional views illustrating a method of manufacturing a light emitting device according to a third embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

10, 110, 210, 310, 410: substrate

20, 40, 120, 140, 220, 240, 320, 340, 420, 440: semiconductor layer

30, 130, 230, 330, 430: active layer

80: bridge wiring 100: light emitting cell

160, 170, 260, 270, 370, 470: conductive film

155, 165, 255, 265, 365: photoresist pattern

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device in which a plurality of cells are combined and a manufacturing method thereof, and more particularly, to a method of connecting a plurality of cells.

A light emitting diode refers to a device that generates a small number of carriers (electrons or holes) injected using a p-n junction structure of a semiconductor, and emits predetermined light by recombination thereof. Such light emitting diodes are used as display elements and backlights. In recent years, power consumption of general light emitting diodes is only several to several tens of those of conventional lighting devices, and their lifetime is several to several tens of times. Superior in terms of durability

In general, in order to use a light emitting diode for lighting, a plurality of light emitting chips may be mounted on a printed circuit board, and then the light emitting chips may be connected in series using wires, and then molded to manufacture light emitting devices, or a plurality of light emitting devices may be used. The devices were connected in series to produce a light emitting device for illumination.

Such a conventional light emitting device for lighting not only has a large size but also has a big limitation in the available power. That is, in order to use such a light emitting device in an AC power source used in a home, a separate AC / DC conversion circuit and a protection circuit must be added. The addition of this circuit not only results in a larger device, but also increases the manufacturing cost of the device.

In addition, when connecting adjacent light emitting chips or light emitting devices through wire bonding using thermal compression, a problem occurs in that the light emitting chips or light emitting devices are damaged by heat or compression. In addition, there is a problem that the device does not operate because the wire for connecting between the light emitting chip or the light emitting device is dropped.

Accordingly, the present invention can reduce the size of the device, simplify the device manufacturing process, manufacturing cost and It is an object of the present invention to provide a light emitting device in which a plurality of cells are arranged, which can reduce a defective rate, which is advantageous for mass production, and a manufacturing method thereof.

It provides a light emitting device comprising a substrate according to the present invention, a plurality of light emitting cells formed on the substrate and bridge wiring for connecting between the N-type semiconductor layer of the adjacent one light emitting cell and the P-type semiconductor layer of the other light emitting cell. .

In this case, the bridge wiring includes at least one conductive film, and the conductive film uses a metal layer having a thickness of 0.001 to 100 μm.

In addition, there is provided a light emitting device comprising the steps of providing a substrate with a plurality of light emitting cells according to the present invention and connecting the N-type semiconductor layer of the adjacent one light emitting cell and the P-type semiconductor layer of the other light emitting cell through a bridge wiring It provides a method for producing.

Here, the step of connecting the N-type semiconductor layer of the adjacent one light emitting cell and the P-type semiconductor layer of the other light emitting cell through the bridge wiring, the N-type semiconductor layer of the one light emitting cell and the P of the other light emitting cell adjacent to the substrate Forming a first photosensitive film pattern exposing a portion of the type semiconductor layer, forming a first conductive film on the entire structure, and forming an upper portion of the N-type semiconductor layer of another light emitting cell adjacent to the first conductive film and other light emission. Forming a second photoresist layer pattern exposing a portion of an upper portion of the P-type semiconductor layer of the cell; forming a second conductive layer in an exposed region of the second photoresist layer pattern; and forming the first and second photoresist layer patterns and the second photoresist layer pattern. And removing the first conductive film in an area except the lower conductive film area. The connecting between the N-type semiconductor layer of one light emitting cell and the P-type semiconductor layer of another light emitting cell through the bridge wiring may include forming an insulating film on the substrate, and removing a portion of the insulating film. Exposing an N-type semiconductor layer and a portion of the P-type semiconductor layer, forming a conductive film on the entire structure, and an upper portion of the N-type semiconductor layer of the adjacent one light emitting cell, an upper portion of the P-type semiconductor layer of the other light emitting cell; And removing the conductive film in the remaining regions except for these interregions.

The preparing of the substrate including the plurality of light emitting cells may include forming an N-type semiconductor layer and a P-type semiconductor layer on the substrate, and removing a portion of the P-type semiconductor layer to form an N-type semiconductor layer. Exposing a portion of the semiconductor substrate and removing a portion of the exposed N-type semiconductor layer to form a plurality of light emitting cells.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention in more detail. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the 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. Like numbers refer to like elements in the figures.

1 is a cross-sectional view illustrating a light emitting device in which a plurality of cells are coupled according to the present invention, and FIGS. 2A to 2D are circuit diagrams for describing a method for combining a plurality of cells according to the present invention.

1 to 2D, the light emitting device of the present invention includes a plurality of light emitting cells 100 formed on a substrate 10, an N semiconductor layer 20 of another light emitting cell 100, and another light emitting cell 100. It includes a bridge wiring 80 for connecting the P semiconductor layer (40) of.

The light emitting cell 100 may include a substrate 10, an N-type semiconductor layer 20 formed on the substrate 10, an active layer 30 formed on a portion of the N-type semiconductor layer 20, It includes a P-type semiconductor layer 40 formed on a portion of the active layer 30.

At this time, the substrate 10 is in the form of a single crystal such as sapphire, silicon, silicon carbide (SiC), aluminum nitride (AlN) or zinc oxide (ZnO).

The N-type semiconductor layer 20 preferably uses a gallium nitride (GaN) film into which N-type impurities are injected, and is not limited thereto. A material layer having various semiconductor properties may be used. In this embodiment, an N-type semiconductor layer 20 including an N _- type Al _x Ga _1-x N (0≤x≤1) film is formed.

In addition, the P-type semiconductor layer 40 preferably uses a gallium nitride film implanted with P-type impurities, and is not limited thereto. A material layer having various semiconductor properties may be used. In this embodiment, a P-type semiconductor layer 40 including a P _- type Al _x Ga _1-x N (0≤x≤1) film is formed. In addition, an InGaN film may be used as the semiconductor layer film.

The N-type semiconductor layer 20 and the P-type semiconductor layer 40 may be formed of a multilayer film. In the above, Si is used as the N-type impurity, Zn is used when InGaAlP is used as the P-type impurity, and Mg is used in the case of nitride.

As the active layer 30, a multilayer film in which a quantum well layer and a barrier layer are repeatedly formed on an N-type Al _x Ga _1-x N (0≤x≤1) film is used. As the barrier layer and the well layer, binary compounds such as GaN, InN, and AlN may be used, and ternary compounds In _x Ga _1-x N (0 ≦ _x ≦ ₁ ) and Al _x Ga _1-x N (0 ≤ _x ≤ 1) may be used, and the quaternary compound Al _x In _y Ga _1-xy N (0 ≦ x + y ≦ 1) may be used. Of course, the N-type semiconductor layer 20 and the P-type semiconductor layer 40 may be formed by implanting predetermined impurities into the two- to four-membered compounds.

Although not shown in the drawing, various material layers may be further added to improve characteristics, purpose of use, and luminous efficiency of the light emitting cell 100. That is, a buffer layer that serves as a buffer may be further formed between the substrate 10 and the N-type semiconductor layer 20.

In addition, a conductive layer using a transparent electrode may be further formed on the P-type semiconductor layer 40 to reduce the resistance of the P-type semiconductor layer. ITO is used as the conductive layer.

Although the above description has been made with respect to the horizontal type light emitting cell, the present invention is not limited thereto and may be applied to the vertical type light emitting cell and the light emitting cell having a flip chip structure.

Subsequently, a bridge wiring for electrically connecting the N-type semiconductor layer 20 and the P-type semiconductor layer 40 of the adjacent light emitting cells 100 through a bridge process or a step cover process, or the like ( 80). The bridge wiring 80 is formed using a conductive material, but is formed using a metal. Of course, it is also possible to use a silicon compound doped with an impurity. A detailed description of the above process for forming the bridge wiring 80 will be described later.

Hereinafter, the connection relationship of the plurality of light emitting cells connected through the bridge wiring will be described.

As illustrated in FIG. 2A, a plurality of light emitting cells 100 are connected in series between the first pad 91 and the second pad 92 through the bridge wiring 80. Also, as shown in FIG. 2B, a plurality of light emitting cells 100 connected in series are formed as one block, and these blocks are parallel between the first and second pads 91 and 92 through the bridge wiring 80. Connected. In addition, as illustrated in FIG. 2C, a plurality of light emitting cells 100 connected in series are connected to the bridge circuit unit 95 through the bridge wiring 80. It is preferable that the thickness of a bridge wiring is 0.001-100 micrometers. Moreover, it is effective to make the space | interval of bridge wiring and the lower semiconductor layer into 0.01-50 micrometers.

The bridge wiring 80 is manufactured through an air bridge process or a step cover process. Hereinafter, a manufacturing method of a light emitting device formed through such a bridge process will be described. In this case, each light emitting cell will be described based on the horizontal type.

3A to 3D are enlarged views of region A of FIG. 1, and are cross-sectional views illustrating a method of manufacturing a light emitting device according to a first embodiment of the present invention.

Referring to FIG. 3A, a plurality of light emitting cells 100 are formed on a substrate 110.

To this end, the N-type semiconductor layer 120, the active layer 130 and the P-type semiconductor layer 140 are sequentially formed on the sapphire substrate. The N-type semiconductor layer 120 is exposed by removing the P-type semiconductor layer 140 and the active layer 130 through a photolithography process using a mask. Subsequently, a portion of the N-type semiconductor layer 120 exposed through a photolithography process using a mask is removed to expose the substrate 110. As a result, the light emitting cells 100 electrically separated from the adjacent light emitting cells 100 are manufactured. An N-type electrode 150 is formed on the N-type semiconductor layer 120. The ohmic electrode layer (not shown) may be further formed on the P-type semiconductor layer 140 without being limited thereto.

Referring to FIG. 3B, the photosensitive film is coated on the entire structure shown in FIG. 3A, and then the N-type electrode 150 region of the adjacent one light emitting cell 100 and the P type of the other light emitting cell 100 are applied through a photolithography process. A first photoresist layer pattern 155 exposing a part of the semiconductor layer 140 is formed, and a first conductive layer 160 is formed along the step of the first photoresist layer pattern 155 thus formed. In this embodiment, the top surface of the N-type electrode 150 is opened by the first photoresist pattern 155, and the side and top surfaces of the P-type semiconductor layer 140 are opened. Therefore, the upper surface of the N-type electrode 150, and the side surface and the upper surface of the P-type semiconductor layer 140 may be electrically connected by the first conductive layer 160. It is preferable to use a metal as the first conductive film 160, and at least one of silver, copper, aluminum, tungsten, and titanium is preferably used. In addition, the conductive film can form a transparent electrode. The first conductive layer 160 may be formed through metal thin film deposition, growth, and metal plating processes.

Referring to FIG. 3C, after the photoresist film is coated on the entire structure shown in FIG. 3B, a second photoresist film pattern 165 having the same shape as the first photoresist film pattern 155 is formed through a photolithography process, thereby forming a first conductive layer. A portion of the deposition 160 is exposed. The second conductive film 170 is formed on the first conductive film 160 exposed by the second photosensitive film pattern 165. In this case, the exposed area of the second photosensitive film pattern 165 may be 1% to 10% wider than the exposed area of the first photosensitive film pattern 155. As the second conductive film 170, a metal having a smaller resistance value than that of the first conductive film 160 is used. Of course, the same metal as the first conductive film 160 may be used as the second conductive film 170. In this embodiment, it is preferable to use at least one of silver, gold and platinum. The second conductive film 170 may also be formed by the same method as the first conductive film 160. In the present embodiment, the second conductive film 170 may be formed through a metal plating process. It is preferable to form the thickness of the second conductive film 170 to be about 1 to 20 thick of the thickness of the first conductive film 160. As a result, the bridge wire formed of the first and second conductive layers 160 and 170 may be prevented from being broken or shorted. Of course, since the resistance of the second conductive film 170 is small, the resistance of the bridge wiring can also be reduced.

Referring to FIG. 3D, the first and second photoresist layer patterns 155 and 165 and the first conductive layer 160 except for the first conductive layer 160 under the second conductive layer 170 may be removed to form a bridge. Form the wiring.

To this end, the second photoresist pattern 165 is removed through the first photoresist strip process. Thereafter, an etching process using the second conductive film 170 as a barrier film is performed to remove the first conductive film 160 in a region except for the lower portion of the second conductive film 170. The first photoresist pattern 155 is removed through the second photoresist strip process. The present invention is not limited thereto, and the order of removing the photosensitive film pattern and the conductive film may be variously performed according to process conditions. That is, the first and second photoresist patterns 155 and 165 may be removed first, and then the first conductive layer 160 may be removed through the photoresist strip process. As a result, a bridge wiring including the first and second conductive layers 160 and 170 is formed to form the N-type electrode 150 of the adjacent one light emitting cell 100 and the P-type semiconductor layer 140 of the other light emitting cell 100. ) Is electrically connected.

After that, although not shown, an N-type pad connected to the N-type semiconductor layer of one light emitting cell positioned at the outermost edge is formed, and a P-type pad connected to the P-type semiconductor layer of another light emitting cell is formed.

The bridge wiring of the present invention can connect the upper portion of the N-type electrode formed on the N-type semiconductor layer of one adjacent light emitting cell to the upper sidewall and the sidewall of the P-type semiconductor layer of the other light emitting cell, as well as the periphery of the N-type electrode. And the upper portion of the P-type semiconductor layer can be connected by bridge wiring. A second embodiment of the present invention will be described with reference to the drawings below. In the following embodiment, a description overlapping with the first embodiment described above will be omitted.

4A to 4C are cross-sectional views illustrating a method of manufacturing a light emitting device according to a second embodiment of the present invention.

Referring to FIG. 4A, a first photoresist layer pattern 255 is formed on a substrate 210 on which a plurality of light emitting cells 100 are formed. At this time, the periphery of the N-type electrode 250 of the adjacent one light emitting cell 100 is opened by the first photoresist film pattern 255 to expose a portion of the N-type electrode 250 and the N-type semiconductor layer 220. A portion of the upper portion of the P-type semiconductor layer 240 of the other light emitting cell 100 is exposed. Thereafter, the first conductive film 260 is formed on the entire structure along the step. In this case, the first conductive film 260 is formed in a shape surrounding the N-type electrode 250. As a result, contact resistance between the first conductive layer 260 and the N-type electrode 250 may be reduced.

Referring to FIG. 4B, a second photosensitive film pattern 265 is formed on the first conductive film 260, and the second conductive film 270 is formed in an area exposed by the second photosensitive film pattern 265.

Referring to FIG. 4C, the adjacent one light emitting cell 100 is removed by removing the first and second photoresist layer patterns 255 and 265 and the first conductive layer 260 in a region except for the lower portion of the second conductive layer 270. The bridge wiring electrically connecting the N-type electrode 250 and the P-type semiconductor layer 240 of the other light emitting cell 100 is formed.

In the above-described embodiment, the bridge wiring is formed of two conductive films, but is not limited thereto and may be formed of a plurality of layers. Of course, the bridge wiring may be formed in a single layer. In addition, a P-type electrode may be formed on the P-type semiconductor layer 240. Such a third embodiment of the present invention will be described with reference to the drawings. In the following embodiment, a description overlapping with the above-described first and second embodiments will be omitted.

5A and 5B are cross-sectional views illustrating a method of manufacturing a light emitting device according to a third embodiment of the present invention.

Referring to FIG. 5A, a photosensitive film pattern 365 is formed on a substrate 310 on which a plurality of light emitting cells 100 are formed. In this case, a portion of the N-type semiconductor layer 320 including the N-type electrode 350 of the adjacent one light emitting cell 100 is exposed by the photosensitive film pattern 365, and the other light emitting cell 100 is the P-type electrode 360. A portion of the P-type semiconductor layer 340 including) is exposed. That is, the top and one sidewall of the N-type electrode 350 and the N-type semiconductor layer 320 adjacent thereto are exposed, and the P-type electrode 360 and a portion of the top and sidewalls of the P-type semiconductor layer 340 adjacent thereto are exposed. Is exposed. Next, the first conductive film 370 for bridge wiring is formed in the region exposed by the photosensitive film pattern 365. At this time, it is preferable to thicken the thickness of the first conductive film 370 sufficiently.

Referring to FIG. 5B, the P-type semiconductor layer in which the N-type electrode 350 of the adjacent one light emitting cell 100 and the P-type electrode 360 of the other light emitting cell 100 are formed by removing the photoresist pattern 365. 340 is electrically connected.

This enables a plurality of light emitting cells to be electrically connected at the wafer level. Of course, the above description has been made regarding the electrical connection between the N-type semiconductor layer of the adjacent one light emitting cell and the P-type semiconductor layer of the other light emitting cell, but is not limited thereto. The N-type semiconductor layers of the light emitting cells may be electrically connected through the above-described method, or the P-type semiconductor layers of one adjacent light emitting cell and the P-type semiconductor layers of the other light emitting cells may be electrically connected. Further, the N-type semiconductor layer of one light emitting cell and the P-type semiconductor layer and / or the N-type semiconductor layer of the plurality of light emitting cells adjacent thereto may be electrically connected. Of course, the reverse of the above is also possible.

The present invention is not limited to the air bridge process described above, and the bridge wiring may be formed through the step cover process. The above-described air bridge process is a technique of connecting two electrodes using a cross-linked conductive film, but the step cover process described below is a technique of connecting the two electrodes by forming a conductive film along a step between the two electrodes.

That is, the semiconductor layer on which the electrode is formed is first insulated with an insulating film such as SiO ₂ , and then the photoresist is applied and developed using a photo process to expose only the electrode portions to be connected to each other, thereby etching and removing the insulating film, and plating or metal deposition thereon. After the ohmic metal and the conductive metal are applied along the steps, and washed with an organic solvent such as acetone, the metal layer on the remaining insulating film except for the electrode part is removed and eventually the two electrodes are electrically energized. Can be. This fourth embodiment of the present invention will be described with reference to the drawings. In the following embodiments, descriptions overlapping with the first to third embodiments described above will be omitted.

6A to 6C are cross-sectional views illustrating a method of manufacturing a light emitting device according to a fourth embodiment of the present invention.

Referring to FIG. 6A, an insulating film 470 is formed on a semiconductor substrate 410 on which a plurality of light emitting cells 100 are formed along a step. At this time, SiO ₂ is used as the insulating film 470.

Referring to FIG. 6B, after the photoresist is coated on the entire structure, a photolithography process using a mask is performed to form a photoresist pattern, and an etching process using the photoresist pattern as an etching mask is performed to form an N-type pad 450 and The insulating film 470 formed on the P-type pad 460 is removed. The insulating layer 470 is removed by exposing only the electrode partial regions connected to each other. Thereafter, the photoresist pattern is also removed. As a result, the N-type pad 450 and the P-type pad 460 are exposed. Of course, the N-type semiconductor layer 420 and the P-type semiconductor layer 440 around the N-type pad 450 and the P-type pad 460 may also be exposed.

Referring to FIG. 6C, the conductive film 480 is formed on the entire structure by a method such as plating or metal deposition. Subsequently, the bridge wiring is removed by removing the conductive metal film except for the N-type pad 450 region of the adjacent one light emitting cell 100, the P-type pad 460 region of the other light emitting cell 100, and the region between them. To form. In FIG. 6C, the conductive film 480 is illustrated as a single metal layer, but is not limited thereto. The conductive film 480 may be formed of a multilayer including an ohmic metal and a conductive metal, and may be thicker than that shown. Removal of the conductive film 480 uses an organic solvent such as acetone.

As described above, the present invention can reduce the size of the device by connecting the adjacent light emitting cells at the wafer level through the bridge wiring.

In addition, a plurality of light emitting cells can be connected in series to provide a light emitting device that can operate even at a high voltage used in the home, it is possible to simplify the manufacturing process of the light emitting device.

In addition, by connecting the light emitting cells at the wafer level without a separate wire connection it is possible to reduce the manufacturing cost and manufacturing failure rate.

Claims (7)

Board; A plurality of light emitting cells formed on the substrate; And And a bridge wiring for connecting between the N-type semiconductor layer of one adjacent light emitting cell and the P-type semiconductor layer of another light emitting cell. The method according to claim 1, The bridge wiring includes at least one conductive film. The method according to claim 2, The conductive film is a light emitting device using a metal layer of 0.001 to 100㎛ thickness. Providing a substrate on which a plurality of light emitting cells are formed; And Connecting the N-type semiconductor layer of the adjacent one light emitting cell and the P-type semiconductor layer of the other light emitting cell through bridge wirings. The method of claim 4, wherein connecting the N-type semiconductor layer of the adjacent one light emitting cell and the P-type semiconductor layer of the other light emitting cell through the bridge wiring comprises: Forming a first photoresist pattern on the substrate to expose an N-type semiconductor layer of one light emitting cell and a portion of the P-type semiconductor layer of another light emitting cell; Forming a first conductive film on the entire structure; Forming a second photoresist layer pattern on the first conductive layer, the second photoresist layer pattern exposing an upper portion of an N-type semiconductor layer of one light emitting cell and a portion of an upper portion of a P-type semiconductor layer of another light emitting cell; Forming a second conductive film in an exposed area of the second photosensitive film pattern; And And removing the first conductive film in a region other than the first and second photoresist pattern and the lower region of the second conductive film. The method of claim 4, wherein connecting the N-type semiconductor layer of the adjacent one light emitting cell and the P-type semiconductor layer of the other light emitting cell through the bridge wiring comprises: Forming an insulating film on the substrate; Removing a portion of the insulating film to expose a portion of the N-type semiconductor layer and the P-type semiconductor layer; Forming a conductive film on the entire structure; And And removing the conductive film over the N-type semiconductor layer of the adjacent one light emitting cell, the P-type semiconductor layer of the other light emitting cell, and the remaining regions except for the region therebetween. The method of claim 4, wherein the preparing of the substrate on which the plurality of light emitting cells is formed comprises: Forming an N-type semiconductor layer and a P-type semiconductor layer on the substrate; Removing a portion of the P-type semiconductor layer to expose a portion of the N-type semiconductor layer; And Removing a portion of the exposed N-type semiconductor layer to form a plurality of light emitting cells.

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