KR100658143B1 - Method for forming the vertically structured gan type light emitting diode device - Google Patents

Abstract

A method for forming a vertically structured GaN type light emitting diode device is provided to prevent damage of a light emitting structure by a laser scribing process. A light emitting structure(110) is formed by laminating an n-type GaN-based semiconductor layer, an active layer, and a p-type GaN-based semiconductor layer on a substrate(100). The light emitting structure is divided into LED units. A plurality of p-type electrodes(120) are formed on the light emitting structure of the LED units. A plating seed layer(130) is formed on the p-type electrode. A structure supporting layer is formed on the plating seed layer. A mask(200) is formed on a lower surface of the substrate corresponding to the plating seed layer. The substrate is divided into the substrate having the light emitting structure without the plating seed layer and the substrate having the light emitting structure and the plating seed layer by an LLO process. An n-type electrode(150) is formed on the exposed light emitting structure of the substrate having the light emitting structure and the plating seed layer.

Description

Method for manufacturing vertically structured gallium nitride based LED device {Method for forming the vertically structured GaN type Light Emitting Diode device}

1A to 1F are cross-sectional views sequentially illustrating a method of manufacturing a vertical gallium nitride based LED device according to the prior art.

FIG. 2 is a plan view illustrating the process cross section shown in FIG. 1B in more detail. FIG.

3A to 3F are cross-sectional views sequentially showing a method of manufacturing a vertical gallium nitride based LED device according to an exemplary embodiment of the present invention.

4 is a plan view illustrating the process cross-sectional view shown in FIG. 3B in more detail.

FIG. 5 is a plan view illustrating the process cross-sectional view shown in FIG. 3C in more detail.

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

100 transparent substrate 110 light emitting structure

112: n-type gallium nitride layer 114: active layer

115: p-type gallium nitride layer 120: p-type electrode

130: metal seed layer 140: structural support layer

150: n-type electrode 200: mask

The present invention relates to a method of manufacturing a vertical structure (vertical electrode type) gallium nitride-based (GaN) light emitting diode (hereinafter, referred to as "LED") device, and more specifically, emits light at the size of a unit LED device. When the structure is separated, the present invention relates to a method of manufacturing a vertical gallium nitride-based LED device that can minimize the separation margin width.

In general, gallium nitride-based LED devices grow on sapphire substrates, but these sapphire substrates are hard, electrically nonconducting, and have poor thermal conductivity, which reduces the size of gallium nitride-based LED devices, thereby reducing manufacturing costs, or reducing light output and chip characteristics. There was a limit to the improvement. In particular, in order to increase the output power of the LED device is required to apply a large current, it is very important to solve the heat emission problem of the LED device.

As a means to solve this problem, a vertical gallium nitride-based LED device in which a sapphire substrate is removed by a laser lift-off (LLO) technique has been proposed.

Next, a method of manufacturing a conventional vertical gallium nitride based LED device will be described in detail with reference to FIGS. 1A to 1F.

1A to 1F are cross-sectional views sequentially illustrating a method of manufacturing a vertical nitride-based LED device according to the prior art.

First, as shown in FIG. 1A, a light emitting structure 110 made of a gallium nitride based semiconductor layer is formed on a transparent substrate 100 such as sapphire. In this case, the light emitting structure 110 has a structure in which the n-type gallium nitride-based semiconductor layer 112, the multi-well GaN / InGaN active layer 114 and the p-type gallium nitride-based semiconductor layer 115 are sequentially stacked Have

As shown in FIG. 1B, a photoresist pattern (not shown) defining a unit LED device having a desired size is formed on the p-type gallium nitride based semiconductor layer 115.

Subsequently, the light emitting structure 110 is separated into the size of a unit LED device through a dry etching process such as an inductive coupled plasma (ICP) using the photoresist pattern as an etching mask.

However, as described above, in order to separate the light emitting structure 110 into the size of a unit LED device, a dry etching process must be performed until the upper surface of the substrate 100 on which the light emitting structure 110 is formed is exposed. . However, when a dry etching process such as an inductively coupled plasma is performed until the upper surface of the substrate 100 is exposed, the n-type and p-type gallium nitride based semiconductor layers 112 and 115, which are the light emitting structures 110, are formed. Since the active layer 114 is exposed to plasma for a long time, damages such as cracks are applied to the exposed n-type or p-type gallium nitride based semiconductor layers 110 and 130 and the active layer 120. It causes the deterioration of device characteristics.

In addition, the manufacturing method of the vertical nitride-based LED device according to the prior art is to proceed to the dicing process to separate the chip (chip), when separating the light emitting structure 110 to the size of the unit LED device, Separation process margin width should be secured. However, in order to cut a dicing blade or laser, a separation process margin width (a) of at least 50 μm must be secured. The number has a problem of decreasing (see Fig. 2).

2 is a plan view illustrating the process cross-sectional view shown in FIG. 1B in more detail.

Then, as shown in FIG. 1C, the p-type electrode 120 and the plating seed layer 130 are sequentially formed on the separated light emitting structure 110, and then, as shown in FIG. 1D, the plating is performed. Electrolytic plating or electroless plating using the seed layer 130 to form a structural support layer 140 made of a plating layer.

Subsequently, as illustrated in FIG. 1E, the substrate 100 is separated from the surface of the light emitting structure 110, that is, the n-type gallium nitride based semiconductor layer 112 through an LLO process.

Then, as shown in FIG. 1F, the n-type electrode 150 is formed on the n-type gallium nitride based semiconductor layer 112 exposed by removing the substrate 100, and then the structural support layer ( 140 is a dicing blade or a laser cutting process to form a plurality of unit gallium nitride based LED chips.

As described above, when the vertical gallium nitride-based LED device is manufactured according to the prior art, the characteristics and reliability of the vertical gallium nitride-based LED device is lowered due to the above problems, and the manufacturing yield of the LED chip is also lowered. There is.

Accordingly, an object of the present invention is to solve the above problems, when separating the light emitting structure to the size of the unit LED device, unit LED without damage and separation process margin of the light emitting structure consisting of gallium nitride-based semiconductor layer and active layer It is to provide a method of manufacturing a vertical gallium nitride-based LED device capable of separating the light emitting structure by the size of the device.

In order to achieve the above object, the present invention is to form a light emitting structure in which the n-type gallium nitride-based semiconductor layer, the active layer and the p-type gallium nitride-based semiconductor layer are sequentially stacked on the substrate, and the light emitting structure is a predetermined size Separating into unit LEDs, forming a plurality of p-type electrodes on the light emitting structure separated by the unit LEDs, and forming a plating seed layer on the p-type electrode; Forming a structural support layer on a seed layer, forming a mask in a region of the lower surface of the substrate corresponding to the plating seed layer, and performing an LLO process on the substrate on which the mask is formed to form the plating seed layer. Separating the substrate having the light emitting structure and the structure supporting layer having the light emitting structure with the plating seed layer formed therein and the light emitting with the plating seed layer formed thereon It provides a method of manufacturing a vertical gallium nitride-based LED device comprising the step of forming each of the n-type electrode on the exposed light emitting structure of the structure supporting layer having a structure.

In addition, in the manufacturing method of the vertical structure gallium nitride-based LED device of the present invention, the step of separating the light emitting structure into a unit LED of a predetermined size, it is preferable to proceed using a laser scribing method.

In addition, in the manufacturing method of the vertical structure gallium nitride-based LED device of the present invention, after separating the light emitting structure into a unit LED of a predetermined size, a plurality of p-type electrodes are formed on the light emitting structure separated by the unit LED Next, plating seed layers may be formed on the plurality of p-type electrodes so as to alternate with each other.

In addition, in the method of manufacturing a vertical gallium nitride-based LED device of the present invention, a light emitting structure having a substrate and a plating seed layer having a light emitting structure in which the plating seed layer is not formed by performing an LLO process on the substrate on which the mask is formed. Sequentially forming a p-type electrode and a plating seed layer on the light emitting structure of the substrate having the light emitting structure in which the plating seed layer is not formed after the separating into the structure supporting layer having a structure supporting layer; And forming an n-type electrode on the exposed n-type gallium nitride-based semiconductor layer by removing the substrate, exposing the n-type gallium nitride-based semiconductor layer. Do.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like reference numerals designate like parts throughout the specification.

Now, a method of manufacturing a vertical gallium nitride based LED device according to an exemplary embodiment of the present invention will be described in detail with reference to FIGS. 3A to 3F.

3A to 3F are cross-sectional views sequentially illustrating a method of manufacturing a vertical gallium nitride based LED device according to an exemplary embodiment of the present invention.

First, as shown in FIG. 3A, the n-type gallium nitride-based semiconductor layer 110, the multi-well GaN / InGaN active layer 120, and the p-type gallium nitride-based semiconductor layer 130 are formed on the substrate 100. A light emitting structure 110 having a structure that is sequentially stacked is formed.

In this case, the substrate 100 on which the light emitting structure 110 is formed is preferably formed using a transparent material including sapphire, and in addition to sapphire, the substrate 100 is zinc oxide (ZnO) or gallium nitrate. It may be formed of gallium nitride (GaN), silicon carbide (SiC), and aluminum nitride (AlN).

In addition, the n-type and p-type gallium nitride based semiconductor layers 112 and 115 and the active layer 114 are Al x In y Ga (1-xy) N composition formula (where 0≤x≤1, 0≤y≤1, 0≤x gallium nitride-based semiconductor material having + y ≦ 1) and may be formed through a known nitride deposition process such as a MOCVD process.

Meanwhile, the active layer 114 may be formed of one quantum well layer or a double hetero structure.

3B, the light emitting structure 110 formed on the substrate 100 is separated into a unit LED device having a predetermined size through a laser scribing process.

Particularly, when the light emitting structure 110 is separated into a unit LED device having a predetermined size, the separation process is shown in FIG. 4 by using a laser scribing process instead of a dry etching process according to the prior art. Since it is not necessary to secure the separation space margin width (see (a) of FIG. 2) to proceed, it is possible to increase the number of devices that can be produced through one wafer having a limited area.

4 is a plan view illustrating the process cross-sectional view shown in FIG. 3B in more detail.

In addition, as described above, when the light emitting structure 110 is separated into unit LED elements having a predetermined size, and a laser scribing process is used, a part such as a photo process than a conventional dry etching process is used. The process can be omitted to simplify the overall manufacturing process of the device. Therefore, the conventional dry etching process, it is possible to solve the problem of the prior art that a defect such as crack (cracks) or conductive material penetration in the light emitting structure (110).

In particular, the p-type gallium nitride based semiconductor layer 130 and the active layer 120 is exposed to the plasma by a dry etching process for a long time, the surface defects such as cracks (cracks) on the surface of the prior art problem is fundamental You can solve it.

Then, as shown in Figure 3c, a plurality of p-type electrode 120 and the plating seed layer 130 are sequentially formed on the light emitting structure 110 separated by the unit LED device size to be staggered. In this case, the plating seed layer 130 serves as a plating crystal nucleus during electrolytic plating or electroless plating for forming a structural support layer to be described later.

More specifically, the plurality of p-type electrode 120 and the plating seed layer 130 according to the present embodiment, as shown in Figure 5, the light emitting structure separated into unit LED device size through a laser scribing process On the upper portion of the 110, that is, on the p-type gallium nitride-based semiconductor layer 115 to be alternately formed, that is, formed in an interlaced manner (interlaced). 5 is a plan view illustrating the process cross-sectional view shown in FIG. 3C in more detail.

That is, according to the present invention, a dicing blade or a laser is used to determine the width of the light emitting structure 110 in which the p-type electrode 120 and the plating seed layer 130 are not formed. In the cutting process, it is possible to use the separation process margin width. In addition, when the width of the light emitting structure in which the p-type electrode 120 and the plating seed layer 130 are not formed is used as the separation process margin width, a sufficient separation process of at least 200 μm or more without a separate wafer area loss. It is possible to secure a margin width, and as a result, it is possible to minimize leakage and short phenomena caused by conductive contaminants generated in a subsequent unit LED chip separation process.

Meanwhile, in the exemplary embodiment of the present invention, the p-type electrode 120 and the plating seed layer 130 are sequentially formed on the light emitting structure 110 to cross each other, but the p-type electrode is formed on the light emitting structure 110. After forming all of the electrodes 120, the plating seed layers are alternately formed on the p-type electrode 120 so as not to affect the characteristics and reliability of the LED device according to the present invention. That is, the p-type electrode 120 may have a different process sequence of forming the p-type electrode according to process conditions.

Then, as shown in Figure 3d, using the plating seed layer 130 as a crystal nucleus electroless or electrolytic plating to form a structural support layer 140 consisting of a plating layer. In this case, the structural support layer 140, the plating seed layer 130 is not formed, the light emitting structure 110 is spaced apart from the upper surface by the height of the plating seed layer 130 and the p-type electrode 120. Away.

In addition, since the structural support layer 140 serves as a supporting layer and an electrode of the final LED device and is formed of a plating layer made of a metal having excellent thermal conductivity, for example, copper, gold, nickel, and the like, the structural support layer 140 is generated in the LED device. Heat can be easily released to the outside. Therefore, even when a high current is applied to the LED element, heat can be efficiently discharged, thereby preventing the phenomenon of deterioration of the characteristics of the LED element even at a high current.

Next, as shown in FIG. 3E, a mask 200 for blocking the laser is formed in a region of the lower surface of the substrate 100 corresponding to the region where the plating seed layer 130 is formed.

Next, an LLO process is performed on the substrate 100 on which the mask 200 is formed. Then, the substrate 100 and the plating seed layer 130 having the light emitting structure 110 in which the portion irradiated with the laser and the portion not irradiated, that is, the plating seed layer 130 is not formed by the mask 200 are formed. It is separated into a structural support layer 140 having a light emitting structure 110 formed.

Then, as shown in FIG. 3F, that is, on the exposed light emitting structure 110 of the structural support layer 140 having the light emitting structure 110 in which the plating seed layer 130 is formed through a conventional electrode forming process. and n-type electrodes 150 are formed on the n-type gallium nitride based semiconductor layer 112, respectively.

Next, the structural support layer 140 is subjected to a dicing blade or laser cutting process to form a plurality of unit vertically structured gallium nitride based LED chips. In this case, in the LED chip separation process, the present invention uses a region (b) in which the light emitting structure in which the p-type electrode 120 and the plating seed layer 130 are not formed is formed as a separation process margin width. A sufficient separation process margin width of at least 200 μm can be secured without loss of wafer area, thereby minimizing leakage and shortening caused by conductive contaminants generated during the separation process.

On the other hand, although not shown, as described above on the light emitting structure of the substrate 100 having the substrate 100 separated through the LLO process, that is, the light emitting structure 110 in which the plating seed layer is not formed, as described above. After the electrode and the plating seed layer are sequentially formed, the method of manufacturing a vertical gallium nitride-based LED device, such as forming a structure support layer on the plating seed layer, may be performed again to recycle the separated substrate 100 again.

Therefore, since the present invention can produce more devices than the prior art by using wafers having the same area, it is possible to improve the manufacturing yield of devices without a separate cost increase.

Although the preferred embodiments of the present invention have been described in detail above, those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Accordingly, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention as defined in the following claims also fall within the scope of the present invention.

As described above, in the present invention, when the light emitting structure is separated into a unit LED size, the surface defect or the active layer of the gallium nitride-based semiconductor layer and the active layer generated during the dry etching process by performing a laser scribing process rather than a dry etching process. Damage to the light emitting structure, such as a short circuit phenomenon caused by the penetration of the conductive material can be prevented.

In addition, in the present invention, by using the laser scribing process, some processes such as a photo process for performing a dry etching process may be omitted, thereby simplifying the overall process of the LED device.

In addition, the present invention does not need to secure the margin width through a separate process to separate the LED chip, it is possible to produce more devices in the wafer having the same area than the conventional to improve the manufacturing yield of the device have.

Therefore, the present invention can not only improve the characteristics and reliability of the vertical gallium nitride-based LED device, but also improve the manufacturing yield of the LED device.

Claims (4)

Forming a light emitting structure in which an n-type gallium nitride-based semiconductor layer, an active layer, and a p-type gallium nitride-based semiconductor layer are sequentially stacked on the substrate; Separating the light emitting structure into unit LEDs having a predetermined size; Forming a plurality of p-type electrodes on the light emitting structure separated by the unit LED so as to cross each other; Forming a plating seed layer on the p-type electrode; Forming a structure support layer on the plating seed layer; Forming a mask in a region of the lower surface of the substrate corresponding to the plating seed layer; Performing a LLO process on the substrate on which the mask is formed to separate the substrate having a light emitting structure in which the plating seed layer is not formed and a structure supporting layer having a light emitting structure in which the plating seed layer is formed; And And forming an n-type electrode on each of the exposed light emitting structures of the structural support layer having the light emitting structure having the plating seed layer formed thereon. The method of claim 1, The separating of the light emitting structure into unit LEDs having a predetermined size may include proceeding using a laser scribing method. The method of claim 1, After separating the light emitting structure into unit LEDs of a predetermined size Forming a plurality of p-type electrodes on the light emitting structure separated by the unit LED, and then manufacturing a vertical gallium nitride-based LED device characterized in that the plating seed layer is formed on the plurality of p-type electrodes to cross each other Way. The method of claim 1, After the LLO process is performed on the substrate on which the mask is formed, separating the substrate having a light emitting structure in which the plating seed layer is not formed and the structure supporting layer having a light emitting structure in which the plating seed layer is formed. Sequentially forming a p-type electrode and a plating seed layer on the light emitting structure of the substrate having the light emitting structure in which the plating seed layer is not formed; Forming a structure support layer on the plating seed layer; Removing the substrate to expose an n-type gallium nitride based semiconductor layer; And And forming n-type electrodes on the exposed n-type gallium nitride-based semiconductor layer, respectively.

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