KR20120117528A - Vertical led and manufacturing methode of thesame - Google Patents

Abstract

PURPOSE: A vertical LED device and a manufacturing method thereof are provided to improve heat dissipation by including a metal layer with a pattern. CONSTITUTION: A p-GaN layer, an active layer, and an n-GaN layer are successively laminated on a light emitting structure. A p type electrode(120) is formed on the p-GaN layer of the light emitting structure. A seed layer(140) covers the side of the light emitting structure and the p type electrode. An n type electrode is formed on the n-GaN layer of the light emitting structure. A metal layer(150) is formed on the seed layer and includes a pattern.

Description

Vertical LED device and its manufacturing method {Vertical LED and manufacturing methode of thesame}

The present invention relates to a vertical LED device and a method of manufacturing the same, and more particularly, to a vertical LED device and a method of manufacturing the same by forming a patterned metal layer on the light emitting structure to improve heat dissipation efficiency.

In general, gallium nitride-based semiconductor device is a material having a relatively high energy band gap has been actively employed in optical devices for generating short wavelength light, such as blue or green.

In order to increase the output power of LED devices, the biggest problem is to release heat generated when a large current is applied quickly. In order to solve this problem, there has been an increasing demand for an LED device having a structure of removing a sapphire substrate having low thermal conductivity and using a material having good thermal conductivity as a substrate, and a vertical LED device has been proposed.

However, it is time to develop a vertical LED device capable of further improving heat dissipation efficiency and a manufacturing method thereof even in a vertical LED device for removing a sapphire substrate.

The present invention has been made to solve the above-described problems of the prior art, a p-type gallium nitride-based semiconductor layer (p-GaN layer), an active layer and an n-type gallium nitride-based semiconductor layer (n-GaN layer) sequentially stacked The light emitting structure, a p-type electrode formed on the p-GaN layer of the light emitting structure, a seed layer formed to cover the side and the p-type electrode of the light emitting structure, an n-type electrode formed on the n-GaN layer of the light emitting structure, and An object of the present invention is to provide a vertical type LED and a method of manufacturing the same, which are formed on the seed layer and include a metal layer on which a pattern is formed, and which has improved heat radiation efficiency.

In order to achieve this object, the vertical LED device according to the present invention is a p-type gallium nitride-based semiconductor layer (p-GaN layer), the active layer and the n-type gallium nitride-based semiconductor layer (n-GaN layer) sequentially stacked Light emitting structure; A p-type electrode formed on the p-GaN layer of the light emitting structure; A seed layer formed to cover a side surface of the light emitting structure and the p-type electrode; An n-type electrode formed on the n-GaN layer of the light emitting structure; And a metal layer formed on the seed layer and having a pattern formed thereon.

The metal layer may include a first metal layer formed on the seed layer; And a second metal layer formed on the first metal layer and being patterned.

The seed layer may be formed to have a shape corresponding to the shape of the light emitting structure.

The first metal layer may have a flat upper portion.

In addition, in the method of manufacturing a vertical LED device according to the present invention, an n-type gallium nitride-based semiconductor layer (n-GaN layer), an active layer, and a p-type gallium nitride-based semiconductor layer (n-GaN layer) are sequentially formed on the substrate. A first step of forming a light emitting structure stacked on the; Forming a p-type electrode on the p-GaN layer of the light emitting structure; Forming a seed layer on the substrate to cover the p-type electrode; Forming a metal layer on the seed layer and forming a pattern on the metal layer; And removing the substrate and forming an n-type electrode on the n-GaN layer of the light emitting structure.

The fourth step may include forming a first metal layer on the seed layer; And forming a PR pattern mask on the first metal layer and then plating to form a second metal layer patterned in the shape of the PR pattern mask.

After the fifth step, a sixth step of attaching the light emitting structure having the second metal layer formed on the heat sink.

In the second step, the light emitting structures may be etched and separated into a plurality, and then p-type electrodes may be formed on the p-GaN layers of the respective light emitting structures.

According to the present invention, a light emitting structure in which a p-type gallium nitride-based semiconductor layer (p-GaN layer), an active layer and an n-type gallium nitride-based semiconductor layer (n-GaN layer) are sequentially stacked, on a p-GaN layer of the light emitting structure A p-type electrode formed on the p-type electrode, a seed layer formed to cover the p-type electrode, and an n-type electrode formed on the n-GaN layer of the light emitting structure and the seed layer, the pattern being formed Including a metal layer can be improved heat dissipation efficiency.

1 is a cross-sectional view of a vertical LED device according to an embodiment of the present invention.
2 is a flow chart showing a vertical LED device manufacturing method according to an embodiment of the present invention.
3 shows each step according to the manufacturing method of FIG. 2.
4 is a flowchart illustrating a method of manufacturing a vertical LED device according to another example of an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing a cross section of a vertical LED device according to an embodiment of the present invention.

Referring to FIG. 1, a vertical LED device 100 according to an embodiment of the present invention includes a light emitting structure 110, a p-type electrode 120, an n-type electrode 130, a seed layer 140, and a metal layer 150. It is configured to include).

The light emitting structure 110 is stacked on a substrate (not shown), which is not shown since the substrate is removed in a later process.

The light emitting structure 110 is also referred to as an epi layer, and has a p-type gallium nitride-based semiconductor layer (p-GaN layer 111), an active layer 113, and an n-type gallium nitride-based semiconductor layer (n-GaN layer) on a substrate. 115 is a semiconductor layer sequentially stacked.

At this time, the p-GaN layer 111, the active layer 113 and the n-GaN layer 115 is Al x In y Ga (1-xy) N composition formula (where 0≤x≤1, 0≤x≤1, 0≤x + y ≤ 1), and a known nitride deposition process such as a metal organic chemical vapor deposition (MOCVD) or a molecular beam crystal growth system (Molecular Beam Epitaxy, MBE) process. It can be formed through.

The active layer 113 may be formed of any one of a multi quantum well or a single quantum well in which several quantum wells are stacked.

Although not shown, a buffer layer and an undoped u-GaN layer may be formed before the n-GaN layer 115 is formed, and may be removed by a subsequent etching process. The buffer layer is a layer that mitigates lattice mismatch between the substrate (not shown) and the light emitting structure 110, and may generally use a gallium nitride-based material.

The p-type electrode 130 is formed on the p-GaN layer 111 of the light emitting structure 110, and the n-type electrode 130 is formed on the n-GaN layer 115 of the light emitting structure 110.

The p-type electrode 120 and the n-type electrode 130 are preferably formed at positions corresponding to each other.

In the vertical LED device 100, when current is applied through the p-type and n-type electrodes 120 and 130, holes and electrons are active layer 113 from the p-GaN layer 111 and the n-GaN layer 115. ) And emit light as electron-hole recombination occurs.

The seed layer 140 is a layer formed in advance in order to facilitate the plating of the metal layer 150. Plating is a coating of a thin layer of another metal on the metal surface. Since the light emitting structure 110 is not a metal, the metal layer 150 may not be plated on the side of the light emitting structure 110. Accordingly, the seed layer 140 is formed to cover the side surface of the light emitting structure 110 and the p-type electrode 120 to form the plating layer 150.

In this case, since the thickness of the light emitting structure 110 is several μm, the seed layer 140 is thinner than 1 μm, so that the seed layer 140 is formed on a substrate (not shown) including the p-type electrode 130. The layer 140 is formed along the shape of the light emitting structure 110.

The metal layer 150 is formed on the seed layer 140. The metal layer 150 may be formed of a material such as copper, gold, a carrier wafer, for example, Si, Ge, GaAs, ZnO, SiC, as a base substrate.

The metal layer 150 is then used as a path for heat dissipation while preventing the light emitting structure 110 from being damaged when performing a laser scribing process to separate the unit LED elements.

In detail, the metal layer 150 includes first and second metal layers 151 and 153.

The first metal layer 151 is formed on the seed layer 140 and has a flat surface that is not in contact with the seed layer 140.

The second metal layer 153 is formed on the first metal layer 151 and is formed to have the same thickness, and is divided into a plated portion and a non-plated portion to have a predetermined shape pattern. As such, the second metal layer 153 is formed of a plated portion and a non-plated portion, and thus has a shape in which unevenness is formed. As a result, the surface area of the first and second metal layers 151 and 153 in contact with the outside by the unevenness is determined. Can be increased.

That is, the metal layer 150 may simultaneously perform a function as a base substrate serving as a support member and a heat dissipation function.

In general, the vertical LED device 100 is used to be attached to the heat sink 170 by the paste (paste, 160), but if the vertical LED device 100 is attached to the heat sink 170 because of the thin nature of the paste 160. The paste 160 may penetrate into a portion where the second metal layer 150 is not plated to further increase the adhesive force.

2 is a flowchart illustrating a method of manufacturing a vertical LED device according to an exemplary embodiment of the present invention, and FIG. 3 is a diagram illustrating each step according to the manufacturing method of FIG. 2.

2 and 3, in step S210, the substrate 101 is prepared as shown in FIG. 3A. The substrate 101 may be formed using a transparent material including sapphire, and zinc oxide (ZnO), gallium nitride (GaN), silicon carbide (SiC), and aluminum nitride (AIN) may be used in addition to sapphire.

The n-GaN layer 115, the active layer 113, and the p-GaN layer 111 are sequentially stacked on the substrate 101.

Although not shown, before the n-GaN layer 115 is formed, an undoped gallium nitride based semiconductor layer (u-GaN layer, not shown) may be further formed on the substrate 101.

In addition, although not shown, the u-GaN layer on the substrate 101 to improve the characteristics of the light emitting structure 110, that is, the epi layer, and to minimize the loss of the epi layer when removing the substrate 101 in a subsequent process. Before stacking (not shown), a buffer layer (not shown) may be further stacked.

As illustrated in FIG. 3B, the stacked light emitting structures 110 are etched and separated into a plurality. The vertical LED device 100 according to the embodiment of the present invention is separated into two light emitting structures 110.

Next, in step S220, as shown in FIG. 3C, the p-type electrode 120 is formed on each p-GaN layer 111 of the plurality of light emitting structures 110.

Next, the seed layer 140 is formed on the substrate to cover the light emitting structure 110 including the p-type electrode 120 as shown in FIG. The seed layer 140 is preferably formed along the shape of the light emitting structure 110.

Next, in step S240 to form a metal layer 150 on the seed layer 140.

The metal layer 150 includes first and second metal layers 151 and 153. First, as shown in FIG. 3E, the first metal layer 151 is formed on the seed layer 140, and the seed It is preferable that the surface not in contact with the layer 140 is formed to be flat.

Thereafter, as shown in FIG. 3F, a second metal layer 153 is formed on the first metal layer 151. First, a PR mask 200 having a predetermined pattern is formed on the first metal layer 151. The second metal layer 153 is plated so that the second metal layer 153 is plated only on a portion where the PR mask 200 is not formed.

As a result, referring to FIG. 3F, when the overall shape of the metal layer 150 is viewed, irregularities are formed on a surface of the second metal layer 153 that is not in contact with the seed layer 140.

Next, the substrate 101 is removed through a laser lift-off (LLO) process, and the light emitting structure 110 is turned upside down so that the support member 150 is lowered to facilitate the subsequent process.

In this case, the removal of the substrate 101 may be performed through a chemical lift off method (CLO) in addition to the LLO using a laser. In view of productivity, the LLO method is more advantageous.

Next, the n-type electrode 130 is formed on the n-GaN 115 of the light emitting structure 120 as shown in FIG. In this case, the n-type electrode 130 is preferably formed at a position corresponding to the p-type electrode 120.

This completes the manufacture of the vertical LED device 100.

Thereafter, the vertical LED device 100 illustrated in FIG. 3H is attached to the heat sink 170 illustrated in FIG. 1 by using a paste, or laser scribing or wheel cutting. Each chip separated by chip separation for cutting the metal layer 150 to include a plurality of light emitting structures 110 may be attached to the heat sink 170.

That is, by forming a pattern on one surface and increasing the surface area, it is possible to manufacture the vertical type LED device 100 in which heat dissipation is efficiently performed.

Meanwhile, in the vertical LED device 100 according to the exemplary embodiment of the present invention, as described above, after forming the first metal layer 151, the second LED layer 153 is formed and the substrate 101 is removed by the process sequence of removing the substrate 101. Although not shown, the second metal layer 153 may be formed on the first metal layer 151 after the first metal layer 151 is formed and the substrate 101 is removed.

4 is a flowchart illustrating a method of manufacturing a vertical LED device according to another example of an embodiment of the present invention.

Referring to FIG. 4, processes (a) to (c) of forming the p-type electrode 220 after forming the light emitting structure 210 on the substrate 201, etching and isolating the plurality, and the like are shown in FIG. Same as the embodiment of the invention.

In this case, before the n-GaN layer 215 is formed, an undoped gallium nitride semiconductor layer (u-GaN layer, not shown) may be further formed on the substrate 201.

In addition, although not shown, the u-GaN layer on the substrate 201 to improve the characteristics of the light emitting structure 210, that is, the epi layer, and to minimize the loss of the epi layer when the substrate 201 is removed in a subsequent process. Before stacking (not shown), a buffer layer (not shown) may be further stacked.

Next, as shown in FIG. 4D, an insulating layer 280 is formed on the substrate to cover side surfaces of the light emitting structure 210 and the p-type electrode 220 so as not to conduct electricity. In this case, the insulating layer 280 should not be formed on the upper surface of the p-type electrode 220 to supply electricity.

Next, as shown in FIG. 4E, the reflective layer 290 is formed on the p-type electrode 220 to improve the luminous efficiency of the vertical LED device 200.

Next, as shown in FIG. 4F, the seed layer 240 is formed on the substrate 201 to cover the reflective layer 290.

Next, as shown in FIG. 4G, a first metal layer 251 is formed on the seed layer 240, and the PR mask 200 is used as shown in FIG. 4H. As shown in 4 (i), the second metal layer 253 is formed.

Finally, as shown in FIG. 4J, an n-type electrode 230 is formed on the n-GaN layer 211 of the light emitting structure 110, and then a paste is applied between the second metal layers 253. By a heat sink (not shown).

As a result, when the overall shape of the metal layer 250 is viewed, the patterned second metal layer 253 has a shape in which unevenness is formed on a surface not in contact with the seed layer 240.

As a result, the vertical LED device of the present invention and a method of manufacturing the light emitting structure in which a p-type gallium nitride-based semiconductor layer (p-GaN layer), an active layer and an n-type gallium nitride-based semiconductor layer (n-GaN layer) are sequentially stacked A p-type electrode formed on the p-GaN layer of the light emitting structure, a seed layer formed to cover the side surface and the p-type electrode of the light emitting structure, an n-type electrode and a seed layer formed on the n-GaN layer of the light emitting structure Is formed to cover, including a metal layer formed with a pattern on a flat surface can be improved heat dissipation efficiency.

In the above, the configuration and operation of the present invention has been shown in accordance with the above description and drawings, but this is merely an example, and various changes and modifications are possible without departing from the spirit and scope of the present invention. .

100: vertical LED element 101: substrate
110: light emitting structure 111: p-GaN
113: active layer 115: n-GaN
120: p-type electrode 130: n-type electrode
140: seed layer 150: metal layer
170: heat sink

Claims (8)

a light emitting structure in which a p-type gallium nitride based semiconductor layer (p-GaN layer), an active layer and an n-type gallium nitride based semiconductor layer (n-GaN layer) are sequentially stacked;
A p-type electrode formed on the p-GaN layer of the light emitting structure;
A seed layer formed to cover a side surface of the light emitting structure and the p-type electrode;
An n-type electrode formed on the n-GaN layer of the light emitting structure; And
And a metal layer formed on the seed layer and having a pattern formed thereon. The method of claim 1,
The metal layer may include,
A first metal layer formed on the seed layer; And
And a second metal layer formed on the first metal layer and being patterned. The method of claim 2,
The seed layer is a vertical LED device, characterized in that formed to have a shape corresponding to the shape of the light emitting structure. The method of claim 2,
The first metal layer is a vertical LED device, characterized in that the top is formed flat. Forming a light emitting structure in which an n-type gallium nitride-based semiconductor layer (n-GaN layer), an active layer and a p-type gallium nitride-based semiconductor layer (n-GaN layer) are sequentially stacked on the substrate;
Forming a p-type electrode on the p-GaN layer of the light emitting structure;
Forming a seed layer on the substrate to cover the p-type electrode;
Forming a metal layer on the seed layer and forming a pattern on the metal layer; And
Removing the substrate and forming an n-type electrode on the n-GaN layer of the light emitting structure. The method of claim 5,
In the fourth step,
Forming a first metal layer on the seed layer; And
Forming a PR pattern mask on the first metal layer and then plating to form a second metal layer to be patterned in the shape of the PR pattern mask; manufacturing method of a vertical LED device comprising a. The method of claim 6,
After the fifth step,
And attaching a light emitting structure having the second metal layer to a heat sink, further comprising a sixth step. The method of claim 5,
The second step comprises:
And etching a plurality of the light emitting structures to isolate them, and then forming p-type electrodes on the p-GaN layers of the respective light emitting structures.

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