KR101273481B1 - White Light-emitting diode and Method of Manufacturing the same - Google Patents

Abstract

The present invention provides a light emitting device including a semiconductor structure, a wavelength conversion layer formed on the semiconductor structure, and a transparent substrate formed on the wavelength conversion layer, and a method of manufacturing the same.

Description

Light emitting device and method of manufacturing the same {White Light-emitting diode and Method of Manufacturing the same}

The present invention relates to a light emitting device and a method of manufacturing the same, and more particularly, to a light emitting device having a uniform color coordinate with a wavelength conversion layer formed on the light emitting device and a method of manufacturing the same.

Light emitting diodes (LED chips) have advantages such as long life, low power consumption, fast response speed, and high output, compared to conventional light sources. It is used as a light source.

Such an LED chip emits light in a single wavelength band such as ultraviolet light or blue, and realizes white light by filling a phosphor resin on the LED chip in a packaging step.

Korean Patent Laid-Open Publication No. 2010-0076639 discloses a chip on board (COB) type LED package, but the method of filling the phosphor resin on the LED chip in the packaging step is mounted on the packaging structure by a dispensing method. The phosphor is applied to the LED chip. However, it is very difficult to control the exact discharge amount of the phosphor resin in the packaging step.

In addition, the thickness of the phosphor layer formed on the LED chip should be formed to have a uniform thickness of 50 ~ 200㎛ can realize a uniform white light color, the uniform thickness of the phosphor layer on the LED chip by dispensing method in the packaging step There is a very difficult problem to form.

As a result, the white light emitted from the LED package becomes non-uniform in color coordinates and has a problem in that yield is lowered.

The present invention is to solve the above problems, to provide a light emitting device having a uniform color coordinate by forming a wavelength conversion layer directly on the LED chip to a uniform thickness.

The present invention also provides a light emitting device manufacturing method capable of realizing white light in a manufacturing step of the LED chip.

An LED chip according to an aspect of the present invention includes a semiconductor structure, a wavelength conversion layer formed on the semiconductor structure, and a transparent substrate formed on the wavelength conversion layer.

At this time, the strength of the transparent substrate is 1.0 Kgf / m ² or more, the thickness may be formed of 150㎛ to 1000㎛.

In addition, the wavelength conversion layer may include a silicone resin and a phosphor in a mixing ratio of 1: 3 to 1:20, and may have a thickness of 30 μm to 100 μm.

The semiconductor structure may further include a conductive reflector formed on the first electrode layer, a first semiconductor layer formed on the conductive reflector, an active layer formed on the first semiconductor layer, and a transparent electrode layer formed on the second semiconductor layer; And a through electrode connected to the transparent electrode layer and exposed through a second semiconductor layer, an active layer, a first semiconductor layer, a conductive reflector, and a first electrode layer in a thickness direction, wherein the through electrode is covered with an insulating film to cover the first electrode. The second semiconductor layer, the active layer, the first semiconductor layer, the conductive reflector, and the first electrode layer are electrically insulated from each other.

An LED chip manufacturing method according to an aspect of the present invention comprises the steps of forming a semiconductor structure spaced at a predetermined interval on a base substrate, forming a wavelength conversion layer on the semiconductor structure spaced at a predetermined interval, Attaching a transparent substrate on the wavelength conversion layer, removing the base substrate, forming an electrode on a rear surface of the exposed semiconductor structure by removing the base substrate, and forming the semiconductor structure into the predetermined structure. Separating along the gap.

According to the present invention, white light having a uniform color coordinate may be implemented in the LED chip unit.

In addition, since the wavelength conversion layer is formed in the LED chip manufacturing step, the step of forming a wavelength conversion layer separately in the LED packaging step can be omitted.

1 is a schematic view of a light emitting device according to an embodiment of the present invention;
2 is a cross-sectional view of a light emitting device according to another embodiment of the present invention;
3 is a bottom view of FIG. 2;
4A is a cross-sectional view of an LED package according to an embodiment of the present invention;
4B is a cross-sectional view of an LED package according to another embodiment of the present invention;
5A to 5G are steps illustrating a method of manufacturing a light emitting device according to an embodiment of the present invention.
6A through 6L are steps illustrating a method of manufacturing a light emitting device according to still another embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail.

It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

Referring to FIG. 1, an LED chip according to an embodiment of the present invention may include a semiconductor structure 100, a wavelength conversion layer 200 formed on the semiconductor structure 100, and the wavelength conversion layer 200. It includes a transparent substrate 300 formed on.

The semiconductor structure 100 may be applied to both an LED chip having a flip chip structure in which an n electrode 180 and a p electrode 190 are formed at the bottom thereof. An LED chip of a flip chip structure, which is epitaxially grown and subsequently removed from a sapphire substrate, may be selected.

The wavelength conversion layer 200 is formed on the semiconductor structure 100. The wavelength conversion layer 200 converts light having a short wavelength emitted from the semiconductor structure 100 into a long wavelength.

Specifically, when the semiconductor structure 100 is a blue LED chip, the wavelength conversion layer 200 includes a phosphor capable of converting blue light into white light. Such a phosphor may generally be a yellow phosphor, and a mixture of red and green phosphors capable of emitting red light and green light may be formed.

In addition, when the semiconductor structure 100 is a UV LED chip, each phosphor capable of emitting blue, green, and red light may be mixed to implement white light.

Since the wavelength conversion layer 200 is formed to have a uniform thickness on the semiconductor structure 100, the light L1 emitted along the optical axis and the light L2 and L3 emitted at a predetermined angle with the optical axis. In all, the distance passing through the wavelength conversion layer 200 becomes relatively uniform.

In the case of forming a hemispherical fluorescent layer convex in a meniscus shape on the semiconductor structure, the distance passing through the phosphor varies according to the emission angle of the light, so that it is difficult to realize uniform white light. Accordingly, the distance through the fluorescent layer is relatively the same regardless of the emission angle of the light by the wavelength conversion layer having a uniform thickness, thereby realizing white light having a uniform color coordinate.

At this time, the thickness of the wavelength conversion layer 200 is preferably 30㎛ to 100㎛. When the thickness of the wavelength conversion layer 200 is 30 μm or less, the distance that the emitted light passes through the wavelength conversion layer 200 is too short to be converted into white light, thereby making it difficult to implement color coordinates and color rendering, and having a thickness of 100 μm. In the case of exceeding the above, the length of the emitted light passing through the wavelength conversion layer 200 is too long, resulting in a problem of low light efficiency.

The wavelength conversion layer 200 plays a role of converting the wavelength of the light emitted from the semiconductor structure 100 and at the same time serves to fix the transparent substrate 300. Therefore, the wavelength conversion layer 200 may not secure sufficient adhesiveness with the transparent substrate 300 required when the sapphire substrate is removed from the semiconductor structure when the thickness is less than 30 μm.

In addition, the wave conversion layer 200 may cover not only the upper surface of the semiconductor structure 100 but also the side surface, and the light emitted from the side surface may also emit uniform white light. In this case, the same thickness of the wavelength conversion layer 200 formed on the upper surface and the side surface of the semiconductor structure 100 is advantageous to realize uniform white light.

If the wavelength conversion layer 200 having a constant thickness is mixed with the phosphor and the silicone resin in a ratio of 1:20 or less, there is a problem in that the concentration of the phosphor is too thin so that it is not easy to convert to white light. When the compounding ratio of 1 is mixed at 1: 3 or more, the concentration of the phosphor is too high to reduce the light efficiency.

In addition, the polymer resin may be any one selected from the group consisting of a silicone resin, an acrylic resin, an epoxy resin, and a mixture thereof, but a high adhesive silicone transparent resin is selected for adhesion with the transparent substrate 300. It is preferable to be.

However, the configuration of the wavelength conversion layer is not necessarily limited thereto, and an additional adhesive layer (not shown) may be further formed to bond the transparent substrate 300.

The transparent substrate 300 is attached to the upper surface of the wavelength conversion layer 200 to maximize the light extraction and protect the damage of the wavelength conversion layer during the packaging process. In addition, the transparent substrate 300 has a strength and a thickness sufficient to support the semiconductor structure 100 when the semiconductor structure 100 is removed from the sapphire substrate.

Specifically, the strength of the transparent substrate 300 is 1.0 Kgf / m ² or more, the thickness is preferably formed to 100㎛ to 1000㎛. If the strength is 1.0 Kgf / m ² or less or the thickness is 100 μm or less, cracks may occur in the transparent substrate 300 or the semiconductor structure 100 may be caused by stress generated when the semiconductor structure 100 is removed from the sapphire substrate. There is a problem that cannot be properly supported.

The transparent substrate 300 may be a glass substrate or a polymer transparent substrate 300 having chemical resistance, heat resistance, and constant strength. In addition, diffusion beads are dispersed inside the transparent substrate 300 to diffuse the incident light, and a prism, a lens, an uneven pattern, etc. are formed on the transparent substrate 300 to induce diffusion or condensation of emitted light. You may.

2 is a cross-sectional view of a light emitting device according to still another embodiment of the present invention, and FIG. 3 is a bottom view of FIG.

The light emitting device according to another embodiment of the present invention includes a semiconductor structure 100, a wavelength conversion layer 200, and a transparent substrate 300. Since the wavelength conversion layer 200 and the transparent substrate 300 are the same as described above, a detailed description thereof will be omitted and the focus will be given on the electrode structure of the semiconductor structure.

The semiconductor structure 100 includes a conductive reflector 400, a first semiconductor layer 110 formed on the conductive reflector 400, an active layer 120 formed on the first semiconductor layer 110, A second semiconductor layer 130 formed on the active layer 120, and a transparent electrode layer 140 formed on the second semiconductor layer 130.

The conductive reflector 400 serves to reflect light emitted from the active layer 120 to the lower portion (in the direction of the conductive reflector) and to electrically connect the first semiconductor layer 110 and the first electrode layer 510. It may be composed of a metal such as Au, Ni, Ag.

The first semiconductor layer 110 may be formed of an n-type nitride semiconductor (GaN), and the active layer 120 may have a quantum well structure and may be formed of GaN or InGaN. In addition, the second semiconductor layer 130 may be formed of a p-type nitride semiconductor (GaN). However, the present invention is not limited thereto, and if necessary, the first semiconductor layer 110 may be a p-type nitride semiconductor, and the second semiconductor layer 130 may be formed of an n-type nitride semiconductor.

The transparent electrode layer 140 is in ohmic contact with the second semiconductor layer 130, and the second semiconductor layer 130, the active layer 120, the first semiconductor layer 110, and the conductive reflector 400 are And a through electrode 141 penetrating the first electrode layer 510 in the thickness direction. At least one through electrode 141 is formed to be electrically connected to the second electrode layer 520 formed at a lower portion thereof.

In this case, the second electrode layer 520 and the transparent electrode layer 140 are electrically connected through the through electrode 141, and a voltage may be applied to the entire surface of the second semiconductor layer 130 by the transparent electrode layer 140. There is this.

The through electrode 141 is covered with the insulating layer 142 so that the second semiconductor layer 130, the active layer 120, the first semiconductor layer 110, the conductive reflector 400, and the first electrode layer 510 are formed. Electrically insulated. In this case, the through electrode 141 may be made of the same or different material as the transparent electrode layer 140.

The first electrode layer 510 is entirely formed on the bottom surface of the conductive reflector 400, and the second electrode layer 520 is formed at the end of the through electrode 141. In this case, the second electrode layer 520 is insulated from the first electrode layer 510 by the insulating layer 142.

Referring to FIG. 3, the second electrode layer 520 is spaced apart from the rear surface of the semiconductor structure 100, and each of the second electrode layers 520 may be connected by a connection electrode 521, and an exposure electrode 523 is formed on the outermost side thereof. It may be configured to be connected to an external electrode terminal (not shown). Specifically, ultrasonic bonding is performed on a substrate having the same electrode pattern as that of the semiconductor structure by using a stud bump, or eutectic bonding using a solder such as Au / Sn or Au / Ag. (eutectic bonding) is possible. At this time, it is obvious that the through-electrode 141 itself without the second electrode layer 520 may be electrically connected to the substrate.

The first electrode layer 510 is electrically insulated from the second electrode layer 520, the connection electrode 521, and the exposure electrode 523, and an exposed portion may be further formed at an end thereof to be connected to an external terminal. Preferably, a groove (not shown) corresponding to the second electrode layer 520, the connection electrode 521, and the exposure electrode 523 may be formed in the first electrode layer 510.

4A is a cross-sectional view of an LED package according to an embodiment of the present invention. The LED package of the present invention may include a light emitting device 1, a body 30 made of a plastic injection molding, a first lead frame 21, a second lead frame 22, and an encapsulant 40.

The body 30 and the lead frames 21 and 22 may all be applied to the configuration of a general LED package. In the light emitting device 1 according to the present invention, since white light is emitted by the wavelength conversion layer formed on the upper surface, it is not necessary to separately mix phosphors in the encapsulant 40, and the wavelength conversion layer is formed to have a uniform thickness, thereby providing a uniform thickness. White light having color coordinates can be realized.

In addition, since the transparent substrate is formed on the wavelength conversion layer, damage to the wavelength conversion layer is prevented in the process of filling the encapsulant 40.

4B is a cross-sectional view of an LED package according to another embodiment of the present invention. The LED package of the present invention is a chip on board (COB) type LED package, specifically, a circuit pattern 51 formed of a material such as copper is formed on a resin-based insulating layer 52. A substrate 50, a light emitting device 1 mounted on the substrate, and an encapsulant 60 covering the light emitting device 1 are included.

As described above, the COB type LED package does not need to separately mix phosphors in the encapsulant 60, and the wavelength conversion layer is formed to have a uniform thickness, thereby realizing white light having a uniform color coordinate.

In addition, since the transparent substrate is formed on the wavelength conversion layer, damage to the wavelength conversion layer is prevented in the process of filling the encapsulant 60.

Hereinafter, a method of manufacturing a light emitting device according to an embodiment of the present invention will be described with reference to FIGS. 5A to 5G. Method of manufacturing a light emitting device according to an embodiment of the present invention comprises the steps of forming a semiconductor structure 100 spaced at a predetermined interval on the base substrate 10, the semiconductor structure 100 spaced at the predetermined intervals Forming a wavelength conversion layer 200 by coating a phosphor on the substrate, attaching the transparent substrate 300 to the wavelength conversion layer 200, removing the base substrate 10, and Forming an electrode on a rear surface of the semiconductor structure 100 from which the base substrate 10 is removed, and separating the semiconductor structure 100 along the predetermined interval.

Forming the semiconductor structures 100 spaced at predetermined intervals on the base substrate 10 (FIGS. 5A and 5B), first, the first semiconductor layer 110 on the sapphire substrate 10 as shown in FIG. 5A. The active layer 120 and the second semiconductor layer 130 are grown using a deposition process such as metal organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE).

Thereafter, as shown in FIG. 5B, the semiconductor structure 100 is removed at a predetermined interval P1 to form the unit semiconductor structure 100. In this case, all of the general scribing methods may be applied as a method of removing the semiconductor structure 100.

Subsequently, in the forming of the wavelength conversion layer (FIG. 5C), the phosphor paste is coated on the semiconductor structure 100 spaced at the predetermined interval P1 to form a predetermined thickness d1 on the upper surface of the semiconductor structure 100. To form a wavelength conversion layer (200).

The phosphor paste may be formed to apply the phosphor paste as a whole so as to fill the space between the semiconductor structures 100 to be spaced apart (P1), and then planarize the top surface by spin coating.

Specifically, the thickness d1 of the wavelength conversion layer 200 may be formed to have a thickness of 30 μm to 100 μm. When the thickness of the wavelength conversion layer 200 is 30 μm or less, the distance that the emitted light passes through the wavelength conversion layer 200 is too short to be converted into white light, and thus color coordinates and color rendering properties are difficult to achieve. If it exceeds, the distance that the emitted light passes through the wavelength conversion layer 200 is too long, which causes a problem in light efficiency.

In addition, if the wavelength conversion layer 200 having a constant thickness is mixed with the phosphor and the silicone resin in a ratio of 1:20 or less, there is a problem in that the concentration of the phosphor is too thin and not easily converted into white light. When the blending ratio of the silicone resin is 1: 3 or more, the concentration of the phosphor is too high to lower the light efficiency.

Attaching the transparent substrate 300 on the wavelength conversion layer 200 (FIG. 5D) is a step of attaching the transparent substrate 300 on the wavelength conversion layer 200 to wafer bonding, a transparent substrate ( The type of 300) may be a tempered glass substrate or a polymer transparent substrate having excellent chemical resistance and heat resistance.

Removing the base substrate 10 (FIG. 5E) may be performed by a dry or wet etching method, but may be preferably performed by a laser lift off (LLO) process. Specifically, when focusing and irradiating a laser light having a predetermined wavelength on the base substrate 10, heat energy is concentrated at the interface between the base substrate 10 and the semiconductor structure 100, and instantaneously at the portion where the laser light passes. Separation will occur.

In this case, since the transparent substrate 300 is adhered to the wavelength conversion layer 200 and firmly supports the semiconductor structure 100, the base substrate 10 may be easily removed.

In addition, when the back surface of the semiconductor structure 100 from which the base substrate 10 is removed is roughened, an additional polishing process may be further performed.

Subsequently, in the forming of the electrode on the back surface of the semiconductor structure 100 (FIG. 5F), the n electrode and the p electrode are formed on the back surface of the semiconductor structure 100 from which the base substrate 10 is removed.

In the configuration of forming the n-electrode and the p-electrode, all general flip chip configurations may be applied. For example, a first electrode layer 180 is formed and electrically connected to a rear surface of the first semiconductor layer 110, and the second electrode layer 190 is electrically connected to the first semiconductor layer 110 and the first electrode layer. Is insulated from each other and voltage can be applied to the second semiconductor layer 130 by a through electrode or the like.

Subsequently, in the separating step (FIG. 5G), laser scribing or breaking may be performed along a predetermined interval at which the semiconductor structures 100 are spaced apart to separate the LED chips.

Hereinafter, a method of manufacturing an LED chip according to another exemplary embodiment of the present invention will be described with reference to FIGS. 6A to 6L. Each step of the LED chip manufacturing method according to another embodiment of the present invention is the same as the manufacturing method of the LED chip described above, and only the configuration for forming the electrode is described as the center.

First, the forming of the semiconductor structure 100 (FIGS. 6A to 6D) is performed by forming the semiconductor structure 100 on the base substrate 10 as shown in FIG. 6A and then spaced apart at predetermined intervals as shown in FIG. 6B. An etching groove is formed on the semiconductor structure 100 to form a flip chip structure electrode as shown in FIG. 6C.

The depth of the etching groove may penetrate through the second semiconductor layer 130 and the active layer 120 and may be formed to a part of the first semiconductor layer 110, and an insulating layer 142 may be formed on the surface of the etching groove. At this time, the insulating layer 142 is formed on the surface of the etching groove SiO ₂ Or by depositing SiN.

Thereafter, as illustrated in FIG. 6D, the transparent electrode layer 140 is formed on the second semiconductor layer 130. In this case, a transparent electrode is filled in the etching groove to form the through electrode 141. The through electrode 141 is electrically insulated from the second semiconductor layer 130, the active layer 120, and the first semiconductor layer 110 by the insulating layer 142.

Thereafter, forming the wavelength conversion layer 200 on the semiconductor structure 100 (FIG. 6E), forming the transparent substrate 300 (FIG. 6F), and removing the base substrate 10 (FIG. 6g) is performed identically.

Subsequently, in the forming of the electrode on the back surface of the semiconductor structure 100 where the base substrate 10 is removed and exposed (FIGS. 6H to 6K), the first semiconductor layer 110 is first formed as shown in FIG. 6H. It etches to the thickness d2 to which 142 is exposed.

Thereafter, the conductive reflector 400 is deposited on the exposed surface of the first semiconductor layer 110 as shown in FIG. 6I. The conductive reflector 400 is deposited to a thickness such that the tip of the insulating layer 142 is exposed using a metal such as Ag, Ni, or Cu.

Thereafter, as shown in FIG. 6J, the end of the insulating layer is removed to form the opening 142a to expose the through electrode 141, and as shown in FIG. 6K, the first electrode layer 510 is formed on the rear surface of the conductive reflector 400. . In this case, the first electrode layer 510 is deposited so as not to be formed in the opening 142a of the insulating layer. If necessary, the opening 142a may be formed by forming the first electrode layer 510 as a whole and then removing the end of the insulating layer.

The second electrode layer 520 is formed in the opening 142a of the insulating layer. In addition, a connection electrode (see FIG. 3) may be formed between the plurality of second electrode layers 520 to be electrically connected to each other. In this case, it is obvious that the second electrode layer 520 and the connection electrode are insulated from the first electrode layer 510. Thereafter, the LED chip manufacturing process is terminated by cutting the LED chip unit as shown in FIG. 6L.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

10: base substrate 100: semiconductor structure
110: first semiconductor layer 120: active layer
130: second semiconductor layer 140: transparent electrode
141: through electrode 142: insulating layer
200: wavelength conversion layer 300: transparent substrate
400: conductive reflector 510: first electrode layer
520: the second electrode layer

Claims (13)

Semiconductor structures;
A wavelength conversion layer formed on the semiconductor structure; And
Including a transparent substrate formed on the wavelength conversion layer,
The transparent substrate has a strength of 1.0 Kgf / m ² or more, the thickness of 100㎛ 1000㎛ light emitting device. delete delete The light emitting device of claim 1, wherein the wavelength conversion layer has a thickness of 30 μm to 100 μm. The light emitting device of claim 1, wherein the wavelength conversion layer covers the side surface of the semiconductor structure. The method of claim 1, wherein the semiconductor structure,
A conductive reflector formed on the first electrode layer;
A first semiconductor layer formed on the conductive reflector;
An active layer formed on the first semiconductor layer;
A second semiconductor layer formed on the active layer;
A transparent electrode layer formed on the second semiconductor layer; And
And a through electrode connected to the transparent electrode layer and exposed through a second semiconductor layer, an active layer, a first semiconductor layer, a conductive reflector, and a first electrode layer in a thickness direction.
The through electrode is covered with an insulating film to electrically insulate the second semiconductor layer, the active layer, the first semiconductor layer, the conductive reflector, and the first electrode layer. The method of claim 6, wherein a second electrode layer connected to the exposed end of the through electrode and a connection electrode electrically connecting the second electrode layer are further formed, wherein the second electrode layer and the connection electrode are connected to the first electrode layer. Light emitting device that is electrically insulated. The light emitting device of claim 7, wherein a groove corresponding to the second electrode layer and the connection electrode is formed on a rear surface of the first electrode layer. Forming semiconductor structures spaced at predetermined intervals on the base substrate;
Forming a wavelength conversion layer on the semiconductor structure spaced at the predetermined intervals;
Attaching a transparent substrate on the wavelength conversion layer;
Removing the base substrate;
Forming an electrode on a rear surface of the exposed semiconductor structure by removing the base substrate; And
And separating the semiconductor structure along the predetermined intervals. The method of claim 9, wherein the forming of the wavelength conversion layer,
The light emitting device manufacturing method for forming the wavelength conversion layer to the side of the semiconductor structure. The method of claim 9, wherein the base substrate is a sapphire substrate. The method of claim 9, wherein the forming of the wavelength conversion layer,
A light emitting device manufacturing method for forming a wavelength conversion layer having a thickness of 30 to 100㎛ on the semiconductor structure. The method of claim 9, wherein the transparent substrate has a thickness of 100 to 1000 μm.

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