KR101026047B1 - Light emitting device array and methods for producing light emitting device array - Google Patents

Abstract

The present invention relates to a light emitting device array and a light emitting device array manufacturing method, the light emitting device array of the present invention comprises: a sub-mount substrate; A plurality of LED cells including a light emitting structure formed by sequentially stacking a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer, wherein the second conductive semiconductor layer is bonded to the sub-mount substrate; An ion implantation layer connecting the plurality of LED cells to be spaced apart from each other while being insulated from each other; And an electrical connection portion electrically connecting the first conductive semiconductor layer of each LED cell to the second conductive semiconductor layer of another LED cell adjacent thereto, thereby adjusting the distance between the LED cells to 50 μm or less. There is an effect of improving the reliability of the light emitting device by reducing the non-uniform light intensity due to the inter-cell shadow effect of the emitted light.

Ion Implantation, Light Emitting Array, LED Cell

Description

LIGHT EMITTING DEVICE ARRAY AND METHODS FOR PRODUCING LIGHT EMITTING DEVICE ARRAY}

The present invention relates to a light emitting device array and a light emitting device array manufacturing method, and more particularly, to a light emitting device array and a method of manufacturing the LED cell arrayed on a single substrate.

Light emitting diodes (LEDs), which are light emitting devices, have been developed in a form in which the size of the chip has a certain size (for example, 1 × 1 mm 2) due to the restriction of current injection. These LEDs have recently been improved in luminous efficiency, and their application ranges from early signal displays to light sources and lighting of large display devices such as backlight units (BLUs) and liquid crystal displays (LCDs) for mobile phones. Is getting wider. The reason for this is that the LED consumes less power and has a longer life than the conventional light bulb or fluorescent lamp.

That is, in order to be used in applications requiring high light output, such as lighting or headlamps that require high light output, it is necessary to manufacture several LED chips in an array form. In this case, a plurality of individual LED chips are connected in series or in parallel through wire bonding, or LED chips on the same substrate are connected and manufactured in a light emitting device array by using a special process.

A general method of manufacturing a light emitting device array first grows an n-type semiconductor layer, an active layer and a p-type semiconductor layer on a sapphire substrate. In order to separate the grown semiconductor layers into a plurality of LEDs, an n-type semiconductor layer, an active layer, and a p-type semiconductor layer are trench-etched to insulate each other. Separate LEDs form n-type electrodes and p-type electrodes, respectively, to form ohmic contacts. In addition, an insulating portion (for example, SiO 2) is formed on the trench and sidewall of the nitride semiconductor light emitting device to be electrically independent, and metal wirings are formed to make a plurality of series or parallel LED chip arrays.

However, in order to form a trench by etching a semiconductor layer (n-type semiconductor layer, active layer, p-type semiconductor layer) in order to fabricate a plurality of LED array, the semiconductor layer (n-type semiconductor layer, during dry etching to form a trench) Active layer, p-type semiconductor layer) there is a problem that can damage. In addition, when bonding individual LEDs separated by a trench etching process onto a substrate, a phenomenon such as a shadow effect occurs when operating a light source due to the limitation of alignment and spacing between chips, and a color temperature difference between chips due to a difference in phosphor coating in manufacturing a light emitting module. And chromatic aberration.

In order to overcome this problem, a large area single chip structure having a variable chip size has been proposed, but a large area single chip structure has a problem that high current injection cannot be avoided due to an increase in the current injection area.

The present invention is to solve the above problems, an object of the present invention is to form an insulating ion implantation layer in the region between the LED cell and the LED cell has an electrically independent structure while maintaining the morphological connection between adjacent LED cells The present invention provides a light emitting device array and a light emitting device array manufacturing method.

A light emitting device array according to an embodiment of the present invention, the sub-mount substrate; A plurality of LED cells including a light emitting structure formed by sequentially stacking a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer, wherein the second conductive semiconductor layer is bonded to the sub-mount substrate; An ion implantation layer connecting the plurality of LED cells to be spaced apart from each other while being insulated from each other; And an electrical connection portion for electrically connecting the first conductive semiconductor layer of each LED cell and the second conductive semiconductor layer of another LED cell adjacent thereto.

In this case, the plurality of LED cells further comprises a first conductive electrode formed on the first conductive semiconductor layer and a second conductive electrode formed on the second conductive semiconductor layer, wherein the electrical connection unit is It is preferable that the bonding wire connects the first conductive electrode of each LED cell and the second conductive electrode of another LED cell adjacent to each LED cell.

The light emitting structure may be partially exposed to the first conductive semiconductor layer by mesa etching, and a first conductive electrode may be formed on the exposed first conductive semiconductor layer. It is preferable that the bonding pad connects the first conductive electrode of the cell and the second conductive electrode of another LED cell adjacent to each of the LED cells.

In this case, the ion implantation layer is formed in at least the first conductive semiconductor layer of the light emitting structure, the ion implantation layer is formed by ion implantation of at least one of H, O, He, Ar and Fe, It is preferable that the space | interval between LED cells is 1 micrometer or more and 200 micrometers or less, Especially, the space | interval between the said LED cells is 50 micrometers or less.

On the other hand, a method of manufacturing a light emitting device array according to another embodiment of the present invention, the step of sequentially growing the first conductive semiconductor layer, the active layer and the second conductive semiconductor layer on the growth substrate to form a light emitting structure; Forming an ion implantation layer by ion implantation in a region excluding the size of the final LED cell of the light emitting structure; Etching the light emitting structure of the region where the ion implantation layer is formed and separating the light emitting structure into a plurality of LED cells; Forming a second conductive electrode on the second conductive semiconductor layer of the separated light emitting structure, and then bonding the second conductive electrode on the sub-mount substrate; Separating the growth substrate from the first conductive semiconductor layer, and then forming a first conductive electrode on a surface from which the growth substrate is removed; And electrically connecting a first conductive electrode of the first conductive semiconductor layer of each LED cell with a second conductive electrode of another LED cell adjacent to each of the LED cells.

In this case, the forming of the ion implantation layer is performed by implanting ions into at least a first conductive semiconductor layer of the light emitting structure, and the forming of the ion implantation layer is performed by H, O, He, Ar And at least one of Fe and an ion implantation layer, wherein forming the ion implantation layer comprises exposing a region other than the size of the final LED cell of the second conductive semiconductor layer to expose the second conductive semiconductor layer. Forming a mask pattern on the layer; And implanting ions into a region of the second conductive semiconductor layer exposed by the mask pattern.

In addition, the separating of the plurality of LED cells is performed by etching the light emitting structure on the ion implantation layer except the ion implantation layer through the mesa etching the light emitting structure, the interval between the LED cells is 1㎛ or more. It is 200 micrometers or less, Especially, it is preferable that the space | interval between the said LED cells is 50 micrometers or less.

According to the present invention, the distance between the LED cells can be adjusted to 50 μm or less, thereby reducing the non-uniform light intensity due to the shadow effect between cells of the emitted light emitted from the LED surface, thereby improving reliability of the light emitting device.

In addition, according to the present invention, by mounting a plurality of LED cells in a single-chip structure having an electrically independent structure while maintaining the morphological connection between adjacent LED cells, it is easy to install the chip on the sub-mount substrate, thereby making a package The failure rate can be reduced, and it can operate at low current.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. Embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art. In addition, it should be considered that elements of the drawings attached to the present specification may be enlarged or reduced for convenience of description.

1 is a view showing a light emitting device array according to an embodiment of the present invention, Figure 1 (a) is a side cross-sectional view of the light emitting device array, Figure 1 (b) is a plan view of the light emitting device array. Here, the light emitting device array has been described by applying a structure in which a plurality of vertical LED cells are arranged, but is not limited thereto. LED cells having a horizontal structure may also be applied.

As shown in FIGS. 1A and 1B, the light emitting device array according to the present embodiment includes a plurality of LED cells formed on the sub-mount substrate 101, an ion implantation layer 170, and an electrical And a connecting portion 193. Here, the electrical connection unit 193 is a component for forming a series or parallel array by electrically connecting each independent LED cell with its adjacent LED cells, and may be implemented as a bonding wire, a bonding pad, or the like.

Each LED cell includes a second conductive electrode 190, a light emitting structure 130 formed on the second conductive electrode 190, and a first conductive electrode 191 formed on the light emitting structure 130. Here, the light emitting structure 130 is formed by sequentially stacking the first conductive semiconductor layer 131, the active layer 133, and the second conductive semiconductor layer 135.

In addition, the first conductive semiconductor layer 131 and the second conductive semiconductor layer 135 have Al _x In _y Ga _(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ x + y≤1) may be formed of a nitride semiconductor material, and representative nitride semiconductor materials include GaN, AlGaN, GaInN, and the like. The first conductive semiconductor layer 131 and the second conductive semiconductor layer 135 may be formed by depositing a nitride semiconductor material (Metal Organic Chemical Vapor Deposition (MOCVD) or Molecular Beam Epitaxy (MBE)). Or by growing on a growth substrate using a known deposition process such as Hybrid Vapor Phase Epitaxy (HVPE).

The active layer 133 is a layer for emitting light and is composed of a nitride layer such as GaN or InGaN having a single or multiple quantum well structure. The active layer 133 is formed using a well-known deposition process such as an organometallic vapor deposition method, a molecular beam growth method, or a hybrid vapor deposition method, like the first conductive semiconductor layer 131 and the second conductive semiconductor layer 135. Can be.

The light emitting structure 130 may further include a buffer layer (not shown) for preventing a defect due to lattice mismatch between the crystal growth substrate and the first conductive semiconductor layer 131.

The ion implantation layer 170 surrounds a portion of the outer surface of the light emitting structure 130 to insulate the adjacent LED cells, thereby maintaining an electrically independent structure while maintaining a morphological connection between the adjacent LED cells.

The ion implantation layer 170 uses an insulating film formed by implanting ions into the first conductive semiconductor layer 131 in one embodiment of the present invention. This is formed by the Fermi level of the semiconductor film being changed by the implanted impurity ions. As impurity ions, at least one ion among elements used for general ion implantation such as H, O, He, Ar, Fe, etc. is used.

Here, the ion implantation technique used to form the ion implantation layer 170 is one of the representative surface modification techniques to accelerate the ion to a high energy to implant the surface of the material to form a modified layer on the surface, The injection depth, distribution and composition can be easily adjusted according to the amount or energy. Since such an ion implantation technique is already known, a detailed description of the process of forming the ion implantation layer is omitted in the present invention.

The electrical connection unit 193 is a bonding wire connecting the first conductive electrode 191 of each LED cell to the second conductive electrode 190 of another LED cell adjacent to each LED cell. In this case, when the LED cell has a horizontal structure, the electrical connection unit 193 may be implemented as a bonding pad.

Here, the sub-mount substrate 101 refers to a wafer for manufacturing a light emitting device array, and at least one of Al ₂ O ₃ , AlN, Si, SiC, GaAs, and GaN may be used.

2A to 2D are cross-sectional side views illustrating a method of manufacturing a light emitting device array according to an exemplary embodiment of the present invention illustrated in FIG. 1. Description of the same components as those of the light emitting device array shown in FIG. 1 will be omitted.

As shown in FIG. 2A, the light emitting structure 230 is formed by sequentially growing the growth substrate 210, the first conductive semiconductor layer 231, the active layer 233, and the second conductive semiconductor layer 235. do. Here, the growth substrate 210 uses a sapphire substrate.

In addition, a buffer layer (not shown) for preventing defects due to lattice mismatch between the growth substrate 210 and the first conductive semiconductor layer 231 may be formed by the growth substrate 210 and the first conductive semiconductor layer 231. It may further include in between.

Subsequently, as shown in FIG. 2B, a photoresist film 251 is formed on the second conductive semiconductor layer 235, and then the photoresist film 251 is patterned to form a photo in the region where the final LED cell is to be formed. The resist pattern 251 is left and the photoresist film 251 is removed to expose the ion implantation region 250 except for the region where the final LED cell is to be formed in the second conductive semiconductor layer 235, thereby forming a mask pattern. do.

Next, an ion implantation process is performed using the mask pattern as an ion implantation mask. That is, the ion implantation layer 270 is formed in the first conductive semiconductor layer 231 by implanting ions into the ion implantation region 250 exposed by the mask pattern. The ion implantation layer 270 is not limited to the first conductive semiconductor layer 231. The ion implantation layer 270 is controlled by ion implantation process conditions, so that ions are transferred to the inside of the light emitting layer 233 and the second conductive semiconductor layer 235. Can be located.

Thereafter, the photoresist film 251 remaining on the second conductive semiconductor layer 235 in the mask pattern is removed. Here, the photoresist film 251 is easily removed using a cleaning solution.

Subsequently, as shown in FIG. 2C, the light emitting structure 230 in which the ion implantation layer 270 is formed is separated into each LED cell through mesa etching. At this time, the first conductive semiconductor layer, the active layer, and the second conductive semiconductor layer on the ion implantation layer 270 are removed and separated into LED cells until the ion implantation layer 270 formed on the first conductive semiconductor layer is exposed. do.

Accordingly, each of the separated LED cells 200 includes a light emitting structure 230 ′ including a first conductive semiconductor layer 231 ′, an active layer 233 ′, and a second conductive semiconductor layer 235 ′, and a second light emitting structure 230 ′. And a second conductive electrode 290 formed on the conductive semiconductor layer 235 '.

At this time, each LED cell is connected only through the other adjacent LED cell and the ion implantation layer 270, thereby maintaining an electrically independent structure while maintaining the morphological connection between adjacent LED cells.

Subsequently, as shown in FIG. 2D, the sub-mount substrate 201 is bonded to the second conductive electrode 290 of the light emitting structure 200 in which the top and bottom of the resultant of FIG. 2C are inverted, and then the growth substrate is attached. The first conductive semiconductor layer 231 ′ is separated from the first conductive semiconductor layer 231 ′.

Then, the first conductive electrode 291 is formed on the first conductive semiconductor layer 231 ', and the first conductive electrode 291 of each LED cell and the other LED cells adjacent to each LED cell are formed. An electrical connection 293 for electrically connecting the second conductive electrode 290 is formed.

Here, the electrical connector 293 is a component for electrically connecting each independent LED cell with its adjacent LED cells to form a series or parallel array, and may be implemented as a bonding wire, a bonding pad, or the like. That is, since one embodiment of the present invention is an LED cell having a vertical structure, the electrical connection portion 293 is formed of a bonding wire. In addition, when the LED cell has a horizontal structure, the electrical connection unit 293 is formed of a bonding pad, and is shown in FIG.

3 is a side cross-sectional view showing another embodiment of a light emitting device array manufactured according to FIGS. 2A to 2D. Description of the same components as those of the light emitting device array shown in FIG. 1 will be omitted.

As shown in FIG. 3, a light emitting device array according to another embodiment of the present invention includes a plurality of LED cells formed on the sub-mount substrate 301, an ion implantation layer 370, and an electrical connection 393. do.

Each LED cell is an LED cell having a horizontal structure, and includes a first conductive semiconductor layer 331, an active layer 333 formed in a partial region of the first conductive semiconductor layer 331, and an agent formed on the active layer 333. A light emitting structure 330 including a second conductive semiconductor layer 335 and a first formed in a region where the active layer 333 and the second conductive semiconductor layer 335 are not formed among the first conductive semiconductor layer 331. The conductive electrode 391 and the second conductive semiconductor layer 335 are formed on the second conductive electrode 390.

Here, the light emitting structure 330 is formed by sequentially stacking the first conductive semiconductor layer 331, the active layer 333, and the second conductive semiconductor layer 335. The light emitting structure 330 may further include a buffer layer (not shown) to prevent defects due to lattice mismatch between the crystal growth substrate and the first conductive semiconductor layer 331.

The ion implantation layer 370 surrounds a portion of the outer surface of the light emitting structure 330 to insulate the adjacent LED cells, thereby maintaining an electrically independent structure while maintaining the morphological connection between the adjacent LED cells.

The electrical connection 393 is formed of a bonding pad that connects the first conductive electrode 391 of each LED cell and the second conductive electrode 390 of another LED cell adjacent to each LED cell.

Here, the sub-mount substrate 301 refers to a wafer for manufacturing a light emitting device array, and at least one of Al ₂ O ₃ , AlN, Si, SiC, GaAs, and GaN may be used.

For reference, a process of manufacturing a LED cell having a horizontal structure will be described in detail. The active layer may be exposed to a portion of the first conductive semiconductor layer 331 by performing mesa etching on the light emitting structure of FIG. 2B. 333 and the second conductive semiconductor layer 335 are etched.

Thereafter, a first conductive electrode 391 is formed on the first conductive semiconductor layer 331 on which the active layer 333 and the second conductive semiconductor layer 335 are not formed, and the second conductive layer that is not etched is formed. The second conductive electrode 390 is formed on the type semiconductor layer 335.

The LED cells thus formed are bonded to the sub-mount substrate 301 on which the bonding pads are formed in the vertically inverted form, and the growth substrate (not shown) is separated from the first conductive semiconductor layer 331.

The present invention is not limited to the above-described embodiment and the accompanying drawings, but is intended to be limited by the appended claims, and various forms of substitution, modification, and within the scope not departing from the technical spirit of the present invention described in the claims. It will be apparent to those skilled in the art that changes are possible.

1 is a side cross-sectional view and a plan view of a light emitting device array according to an embodiment of the present invention;

2A to 2D are side cross-sectional views for each process for explaining a method of manufacturing a light emitting device array according to an embodiment of the present invention illustrated in FIG. 1, and

3 is a side cross-sectional view showing another embodiment of a light emitting device array manufactured according to FIGS. 2A to 2D.

Claims (16)

Sub-mount substrate; A plurality of LED cells including a light emitting structure formed by sequentially stacking a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer, wherein the second conductive semiconductor layer is bonded to the sub-mount substrate; An ion implantation layer connecting the plurality of LED cells to be spaced apart from each other while being insulated from each other; And And an electrical connection portion electrically connecting the first conductive semiconductor layer of each LED cell to the second conductive semiconductor layer of another LED cell adjacent thereto. The method of claim 1, The plurality of LED cells are formed between the first conductive electrode formed on the first conductive semiconductor layer and the second conductive semiconductor layer and the sub-mount substrate so as to be electrically connected to the second conductive semiconductor layer. The light emitting device array further comprises a second conductive electrode. The method of claim 2, And the electrical connection part is a bonding wire connecting the first conductive electrode of each LED cell and the second conductive electrode of another LED cell adjacent to each of the LED cells. The method of claim 1, The light emitting structure of claim 1, wherein a portion of the first conductive semiconductor layer is exposed by mesa etching, and a first conductive electrode is formed on the exposed first conductive semiconductor layer. The method of claim 4, wherein And the electrical connection part is a bonding pad connecting the first conductive electrode of each LED cell to the second conductive electrode of another LED cell adjacent to each of the LED cells. The method according to claim 3 or 5, And the ion implantation layer is formed on at least the first conductive semiconductor layer of the light emitting structure. The method of claim 6, The ion implantation layer is a light emitting device array, characterized in that formed by the ion implantation of at least one of H, O, He, Ar and Fe. The method according to claim 3 or 5, The light emitting device array, characterized in that the interval between the LED cell is 1㎛ more than 200㎛. The method of claim 8, Light emitting device array, characterized in that the spacing between the LED cell is 50㎛ or less. Sequentially growing a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer on the growth substrate to form a light emitting structure; Forming an ion implantation layer by ion implantation in a region excluding the size of the final LED cell of the light emitting structure; Etching the light emitting structure of the region where the ion implantation layer is formed and separating the light emitting structure into a plurality of LED cells; Forming a second conductive electrode on the second conductive semiconductor layer of the separated light emitting structure, and then bonding the second conductive electrode on the sub-mount substrate; Separating the growth substrate from the first conductive semiconductor layer, and then forming a first conductive electrode on a surface from which the growth substrate is removed; And And electrically connecting a first conductive electrode of the first conductive semiconductor layer of each LED cell to a second conductive electrode of another LED cell adjacent to each of the LED cells. The method of claim 10, Forming the ion implantation layer by implanting ions into at least a first conductive semiconductor layer of the light emitting structure. The method of claim 11, The forming of the ion implantation layer may include forming a mask pattern on the second conductive semiconductor layer to expose a region of the second conductive semiconductor layer except for the size of the final LED cell; And And implanting ions into a region of the second conductive semiconductor layer exposed by the mask pattern. The method of claim 11, Forming the ion implantation layer, method of manufacturing a light emitting device array, characterized in that performed by the ion implantation of at least one of H, O, He, Ar and Fe. The method of claim 10, The separating of the plurality of LED cells may be performed by etching the light emitting structure on the ion implantation layer except the ion implantation layer through mesa etching of the light emitting structure. The method of claim 10, The interval between the LED cell is a light emitting device array manufacturing method, characterized in that more than 1㎛ 200㎛. The method of claim 15, The spacing between the LED cells is 50㎛ or less method of manufacturing a light emitting element array.

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