KR100752721B1 - Method for forming the vertically structured gan type light emitting diode device - Google Patents

Abstract

A method for fabricating a GaN-based LED device with a vertical structure is provided to prevent the width of an active layer from being decreased by making the lateral surface of a unit LED have an inclined surface with an inclination angle smaller than 90 degrees with respect to the surface of a structure support layer when a light emitting structure is divided into a size of a unit LED. A light emitting structure(110) in which an n-type GaN-based semiconductor layer(112), an active layer(114) and a p-type GaN-based semiconductor layer(115) are sequentially stacked is formed on the upper surface of a substrate. The light emitting structure is divided into a predetermined size by a laser scribing method in a manner that the lateral surfaces of unit LED's are interconnected. A p-type electrode(120) is formed on each light emitting structure divided into the unit LED's. A plating seed layer(130) is formed on the p-type electrode. A structure support layer(140) is formed on the plating seed layer. The substrate is removed to expose the n-type GaN-based semiconductor layer. The exposed n-type GaN-based semiconductor layer, the active layer and the p-type GaN-based semiconductor layer are sequentially etched and divided in a manner that the lateral surface of the divided unit LED is inclined with respect to the surface of the structure support layer. An n-type electrode(150) is formed on the exposed surface of the divided n-type GaN-based semiconductor 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 3G 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.

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

<Explanation of symbols for main parts of the drawings>

100 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

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. The present invention relates to a method of manufacturing a vertical gallium nitride based LED device capable of realizing high brightness by minimizing the separation margin width and increasing the reflection surface when the structure is separated.

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 a 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 light emitting structure 110 includes the p-type gallium nitride based semiconductor layer 115, the active layer 114, and the like. Since the n-type gallium nitride-based semiconductor layer 112 is exposed to plasma for a long time, the side surfaces of the p-type gallium nitride-based semiconductor layer 115 and the active layer 114 that are exposed in advance are n-type gallium nitride-based semiconductor layer 112. Since a larger amount is removed by etching than the side surface of the active layer 114, the width (a) of the active layer 114, that is, the area of the layer generating light decreases, thereby decreasing luminance characteristics.

In addition, the manufacturing method of the vertical nitride-based LED device according to the prior art is to proceed to the dicing (dicing) process to separate the chip (chip), the light emitting structure 110 to the size of the unit LED device When separating, the separation process margin width (b) must be secured. However, in order to cut a dicing blade or a laser, a separation process margin width (b) 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 reflective 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 electroplating or electroless plating is performed using the plating seed layer 130 to form a structural support layer 140 formed 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 (arrow).

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

However, the vertical gallium nitride-based LED device manufactured according to the prior art is due to the width of the p-type gallium nitride-based semiconductor layer 115 narrowed through the process of separating each of the unit LED device size (see Figure 1b) The width of the p-type electrode 120 and the plating seed layer 130 formed thereon is also narrow.

However, when the width of the p-type gallium nitride-based semiconductor layer 115 is formed as described above, the light generated by the active layer 114 is completely absorbed by the structural support layer 140 formed on the wider width. Difficult to prevent

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 To provide a method of manufacturing a vertical gallium nitride-based LED device that can separate the light emitting structure by the size of the device and at the same time minimize the reduction of the area of the layer for generating light by reducing the width of the active layer during the separation process have.

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 side portions of the unit LEDs to be bonded to each other, forming a p-type electrode on each light emitting structure separated by the unit LEDs, forming a plating seed layer on the p-type electrode, and Forming a structure support layer on a plating seed layer, exposing the n-type gallium nitride based semiconductor layer by removing the substrate, exposing the n-type gallium nitride based semiconductor layer, the active layer, and the p-type gallium nitride based Separating side surfaces of the unit LEDs separated from each other by sequentially etching the semiconductor layers so as to be inclined with respect to the surface of the structure supporting layer, and side surfaces of the unit LEDs are inclined. To separate provides a method for producing the vertical structure GaN-based LED element and forming a n-type electrode on the exposed surface of the n-type gallium nitride-based semiconductor layer.

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 to be bonded to each other by a unit size of a predetermined size, it is preferable to proceed using a laser scribing method. Do.

In addition, in the manufacturing method of the vertically structured gallium nitride-based LED device of the present invention, the unit LED is separated so that the exposed n-type gallium nitride-based semiconductor layer, the active layer and the p-type gallium nitride-based semiconductor layer sequentially etched and bonded to each other. In the separating of the side surface of the structure supporting layer to be inclined with respect to the surface, it is preferable that the side surface of the separated unit LED is formed to have an inclination angle of less than 90 ° with respect to the surface of the structure supporting layer.

In addition, in the method of manufacturing a vertical gallium nitride-based LED device of the present invention, the p-type electrode or the plating seed layer is a metal having a reflective to prevent the light generated in the active layer is absorbed and lost to the structure support layer It is preferable to form using.

Further, in the method of manufacturing the vertically structured gallium nitride based LED device of the present invention, after removing the substrate to expose the n-type gallium nitride-based semiconductor layer, the exposed n-type gallium nitride-based semiconductor layer surface It is preferable that the step further comprises the step of forming an uneven pattern.

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 3G.

3A to 3G 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.

Then, as shown in Figure 3b, the light emitting structure 110 formed on the substrate 100 is separated by a laser scribing (laser scribing) process so that the sides are bonded to each other with a unit LED of a predetermined size.

In particular, when the light emitting structure 110 is separated into a unit LED device having a predetermined size, the laser scribing process is used instead of the dry etching process according to the prior art, as shown in FIG. Since it is not necessary to secure a separation space margin width (see (b) of FIG. 2) to proceed with the separation process, 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.

Then, as shown in FIG. 3c, the p-type electrode 120 and the plating seed layer 130 are sequentially formed on each light emitting structure 110 separated by the unit LED device size.

Meanwhile, the p-type electrode 120 and the plating seed layer 130 according to the present invention are preferably made of a reflective metal. This is to prevent the light generated in the active layer from being absorbed and extinguished by the structural support layer described later.

In addition, 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.

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 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, 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.

Then, as shown in FIG. 3E, an LLO (arrow) process is performed to separate the substrate 100 and the light emitting structure 110. At this time, the substrate 100 is removed from the light emitting structure 110 through the LLO process, the n-type gallium nitride based semiconductor layer 112 of the light emitting structure 110 is exposed.

3F, the n-type gallium nitride-based semiconductor layer 112, the active layer 114, and the p-type gallium nitride-based semiconductor layer 115 are sequentially etched to be bonded to each other. The side of the unit LED is separated again so as to be inclined with respect to the surface of the structure support layer 140.

The separation process according to the present invention will be described in detail. First, a photoresist pattern (not shown) defining a unit LED device having a desired size is formed on the exposed n-type gallium nitride based semiconductor layer 112.

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.

Meanwhile, in the separation process, the light emitting structure 110 is exposed to the plasma for a long time in the order of the p-type gallium nitride based semiconductor layer 115, the active layer 114, and the n-type gallium nitride based semiconductor layer 112. Unlike the prior art, since the n-type gallium nitride-based semiconductor layer 115, the active layer 114, and the p-type gallium nitride-based semiconductor layer 112 are exposed to the plasma for a long time, the n-type gallium nitride-based semiconductor layer is exposed in advance. A larger amount is etched than that of the active layer 114 and the p-type gallium nitride based semiconductor layer 115 where the side of 112 is exposed behind it. Accordingly, the side surface of the unit LED separated according to the present invention has an inclination angle smaller than 90 ° with respect to the surface of the structure support layer 140, while the side surface of the unit LED separated according to the prior art is formed on the surface of the structure support layer 140. It has an inclination angle greater than 90 ° with respect to it.

In other words, the width of the active layer 114 of the unit LED separated according to the present invention (see (e) of FIG. 3F) is greater than the width of the active layer of the unit LED separated according to the prior art (see (a) of FIG. 1B). Since it has a wide width, the amount of light generated can also be increased further than in the prior art to improve the brightness.

In addition, the manufacturing method of the vertical nitride-based LED device according to the prior art is to proceed to the dicing (dicing) process to separate the chip (chip), the light emitting structure 110 to the size of the unit LED device At the time of separation, the separation process margin width (see FIG. 2A) must be secured. However, since the side surface of the unit LED for dicing blade or laser cutting is made of an inclined surface having an inclination angle of 90 ° or less with respect to the surface of the structural support layer 140, It is possible to proceed with the separation process without securing the separation process margin width.

Then, as illustrated in FIG. 3G, n-type electrodes 150 are formed on the exposed surfaces of the separated n-type gallium nitride based semiconductor layers 112 through a conventional electrode forming process, respectively.

Next, the structure 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 addition, the vertical gallium nitride-based LED device manufactured according to the present invention, as shown in Fig. 3g, it is possible to sufficiently secure the width of the reflective p-type electrode 120 and the plating seed layer 130 It is possible to minimize the phenomenon that the light generated in the active layer 114 is absorbed and extinguished by the structure support layer 140 formed thereon.

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, when the light emitting structure is separated into unit LED sizes, the side surface of the unit LED is formed as an inclined surface having an inclination angle of less than 90 ° with respect to the surface of the structure supporting layer, so that the width of the active layer is reduced, In other words, it is possible to prevent the area for generating light from being reduced, thereby improving luminance characteristics.

In addition, since the present invention does not have to secure a 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 in the prior art, thereby improving the manufacturing yield of the devices. 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 (6)

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 such that side surfaces are bonded to each other by unit LEDs having a predetermined size; Forming p-type electrodes on each light emitting structure separated by the unit LEDs; Forming a plating seed layer on the p-type electrode; Forming a structure support layer on the plating seed layer; Removing the substrate to expose the n-type gallium nitride based semiconductor layer; Separating the n-type gallium nitride-based semiconductor layer, the active layer, and the p-type gallium nitride-based semiconductor layer by sequentially etching sidewalls of the unit LEDs which are separated to be bonded to each other so as to be inclined with respect to the surface of the structure support layer; And And forming an n-type electrode on an exposed surface of the n-type gallium nitride-based semiconductor layer separated to incline the side of the unit LED. The method of claim 1, Separating the light emitting structure so that the side surfaces are bonded to each other by a unit size of a predetermined size, the method of manufacturing a vertical gallium nitride-based LED device, characterized in that proceeding using a laser scribing method. The method of claim 1, The method may further include separating the n-type gallium nitride-based semiconductor layer, the active layer, and the p-type gallium nitride-based semiconductor layer by sequentially etching sidewalls of the unit LEDs separated from each other so as to be inclined with respect to the surface of the structure support layer. The method of manufacturing a vertical gallium nitride-based LED device, characterized in that the side of the separated unit LED is formed to have an inclination angle of less than 90 ° with respect to the surface of the structure support layer. The method of claim 1, The p-type electrode is a method of manufacturing a vertical gallium nitride-based LED device, characterized in that formed using a reflective metal. The method of claim 1, The plating seed layer is a method of manufacturing a vertical gallium nitride-based LED device, characterized in that formed using a reflective metal. The method of claim 1, After removing the substrate to expose the n-type gallium nitride based semiconductor layer, further comprising forming a concave-convex pattern on the exposed n-type gallium nitride based semiconductor layer. Method of manufacturing the LED device.

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