KR100744024B1 - Method of manufacturing light emitting diode - Google Patents

Abstract

A method for fabricating an LED is provided to improve process efficiency by simultaneously forming transparent electrodes connected to positive and negative terminals. A light emitting structure(123) is formed on a substrate(100), including a semiconductor layer of a first conductivity type, a light emitting active layer partially exposing the semiconductor layer of the first conductivity type, and a semiconductor layer of a second conductivity type. The light emitting structure is covered with a passivation layer having first and second openings respectively exposing the semiconductor layer of the first conductivity type and the semiconductor layer of the second conductivity type. First and second electrodes are simultaneously formed in the first and second openings, coming in contact with the semiconductor layer of the first conductivity type and the semiconductor layer of the second conductivity type. The process for forming the passivation layer includes the following steps. An insulation layer is conformally formed on the light emitting structure. The insulation layer is selectively patterned to partially expose the semiconductor layer of the first conductivity type and the semiconductor layer of the second conductivity type.

Description

Manufacturing method of light emitting diodes {METHOD OF MANUFACTURING LIGHT EMITTING DIODE}

1 is a plan view illustrating a light emitting diode (LED) according to the present invention.

2 to 9 are cross-sectional views taken along line II ′ of FIG. 1 for explaining a method of manufacturing a light emitting diode according to the present invention.

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

100 substrate 110 type 1 semiconductor layer

110a: type 1 semiconductor pattern 112: electrode region

120: light emitting active layer 120a: light emitting active pattern

123: light emitting structure 130: second type semiconductor layer

130a: type 2 semiconductor pattern 140: protective film

140a: Protective pattern 142: First opening

144: second opening 150: metal electrode film

150a: first electrode 150b: second electrode

160: mask pattern 170a, 170b: metal electrode

The present invention relates to a method of manufacturing a light emitting diode, and more particularly, to a method of manufacturing a light emitting diode including an insulating film for insulating the electrode and the light emitting structure.

A light emitting diode (LED) is a kind of semiconductor device that emits light when a current flows in a forward direction. The light is energy emitted by the combination of electrons and holes, and is in the form of electroluminescence. The color of light emitted from the light emitting diode is determined by the type and condition of the material used.

The light emitting diode has many advantages when compared with a conventional light bulb. For example, the light emitting diode emits more light per watt, which is advantageous in terms of power consumption. In addition, the light emitting diode may display a desired color on its own without using a color filter, which is more cost effective. In addition, the light emitting diode is well known for a long life, it can be made small enough, and the lighting and lighting time is very short. Therefore, the light emitting diode is applied to various products such as lamps and displays and is continuously studied.

Hereinafter, a conventional method for manufacturing a light emitting diode will be described.

The light emitting diode includes a sapphire substrate and a light emitting structure formed on the sapphire substrate. The light emitting structure includes an n-type region layer, an active layer having a multi-quantum well (MQW) structure, and a p-type region layer sequentially formed on the sapphire substrate.

Portions of the n-type region layer are exposed by dry etching a portion of the p-type region layer and the active layer. In general, a transparent electrode is formed on the p-type region layer to improve luminance while increasing the current injection area. For example, the transparent electrode may include indium tin oxide (ITO). An ITO film is formed on the p-type region layer, the active layer and the n-type region layer as a whole. Thereafter, the ITO film is patterned to form a transparent electrode selectively on the p-type region layer. Subsequently, an n-type metal electrode may be selectively formed on the exposed n-type region layer, and a p-type metal electrode may be formed on the transparent electrode.

In forming the transparent electrode, the n-type metal electrode, and the p-type metal electrodes, an electrode residue may remain on sidewalls of the light emitting structure after patterning is completed. Therefore, when the light emitting diode is operated, current flows through the residue, which lowers the reliability of the light emitting diode, or the light emitting diode may not operate.

Accordingly, an object of the present invention for solving the above problems is to provide a method of manufacturing a light emitting diode with improved reliability of the light emitting diode.

According to another aspect of the present invention, there is provided a light emitting structure including a first type semiconductor layer, a light emitting active layer exposing a portion of the first type semiconductor layer, and a second type semiconductor layer. Forming a passivation layer having a first opening and a second opening on the exposed first type semiconductor layer and the second type semiconductor layer, and the first type semiconductor layer and the first and second openings, respectively. Simultaneously forming a first type electrode and a second type electrode in contact with the second type semiconductor layer, respectively.

In example embodiments, the forming of the passivation layer may include conformally forming an insulating layer on the light emitting structure, and selectively forming the insulating layer to expose a portion of the second type semiconductor layer and the first type semiconductor layer. Patterning may be included.

According to another embodiment, the forming of the first type and the second type electrode may include forming a transparent electrode layer on the passivation layer including the first and second openings, and the transparent portion in which the first and second openings are located. Forming a mask pattern on an electrode film, etching the exposed transparent electrode film using the mask pattern, and removing the mask pattern.

According to another embodiment, the transparent electrode film may be an ITO film.

According to another embodiment, the passivation layer may include silicon oxide.

According to another embodiment, the first type is n-type and the second type is p-type.

According to another embodiment, the method may further include forming metal electrodes connected to the first type electrode and the second type electrode, respectively.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the following examples and can be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosure may be made thorough and complete, and to fully convey the spirit of the present invention to those skilled in the art. In the drawings, the thicknesses of layers and regions are exaggerated for clarity. Parts denoted by the same reference numerals throughout the specification represent the same components.

1, a light emitting diode of the present invention is described.

Referring to FIG. 1, the light emitting diode includes a first type semiconductor pattern 110a sequentially formed on the sapphire substrate 100, a light emitting active pattern (not shown) having a multi-quantum well structure, and a second type semiconductor pattern 130a. It includes a light emitting structure (not shown). For example, the first type semiconductor pattern 110a may be an n-type GaN film, and the light emitting active pattern (not shown) of the multi-quantum well structure may include a GaN film, an InGaN film, or an InGaN film doped with zinc or silicon. The second type semiconductor pattern 130a may be a p-type GaN film.

The second type semiconductor pattern 130a exposes a portion of the first type semiconductor pattern 110a and a first electrode including a transparent electrode, for example, ITO, on the exposed first type semiconductor pattern 110a. 150a may be formed. In this case, a second electrode 150b may be formed on the second type semiconductor pattern 130a.

Metal electrodes 170a and 170b including chromium and / or gold for lowering contact resistance with terminals may be further formed on the first electrode 150a and the second electrode 150b, respectively.

2 to 9, a method of manufacturing a light emitting diode according to the present invention will be described.

2, a substrate 100 for manufacturing a light emitting diode is provided. For example, the substrate 100 may be a substrate capable of growing a crystal of a nitride semiconductor such as GaN, and a sapphire substrate may be used.

The first type semiconductor layer 110, the light emitting active layer 120, and the second type semiconductor layer 130 are sequentially formed on the substrate 100. For example, the first type semiconductor layer 110 may be an n-type GaN film. The first type semiconductor layer 110 may be formed by an epitaxial process such as metal organic chemical vapor deposition (MOCVD). The first type semiconductor layer 110 may be formed by forming a seed layer (not shown) and then growing the seed layer. In this case, a buffer layer (not shown) may be further interposed between the seed layer and the substrate to relieve stress. For example, the buffer layer may include AlN.

The light emitting active layer 120 is formed on the first type semiconductor layer 110. The light emitting active layer 120 may have a multi-quantum well (MQW) structure. For example, the light emitting active layer 120 may include a GaN film, an InGaN film, or an InGaN film doped with zinc or silicon.

The second type semiconductor layer 130 is formed on the light emitting active layer 120. For example, the second type semiconductor layer 130 may be a p-type GaN film. Each layer is composed of Liquid Phase Epitaxy (LPE), Vapor Phase Epitaxy (VPE), Metal Organic Chemical Vapor Deposition (MOCVD) and Molecular Beam Epitaxy (MBE). It may be formed by an epitaxial method such as.

Referring to FIG. 3, the electrode region 112 of the first type semiconductor layer 110 is exposed by patterning the second type semiconductor layer 130 and the light emitting active layer 120. In this case, an upper portion of the first type semiconductor layer 110 may be patterned to reduce its thickness. Accordingly, the light emitting structure 123 including the first type semiconductor pattern 110a, the light emitting active pattern 120a, and the second type semiconductor pattern 130a may be formed. For example, the patterning may be performed by performing dry etching.

Referring to FIG. 4, a passivation layer 140 is formed on the light emitting structure 123 and the substrate 100. The passivation layer 140 insulates and protects the light emitting structure 123. For example, the passivation layer 140 may include an insulating material and may be a silicon oxide layer. The protective layer 140 may be formed by chemical vapor deposition (CVD). In particular, the protective layer 140 may be formed by a Plasma Enhanced CVD (PECVD) method to be formed without damage at low temperatures. Alternatively, the passivation layer 140 may be formed by a sputtering method. The passivation layer 140 may have a thickness of about 1000 to 2000 μs in consideration of insulation ability and process efficiency.

4 and 5, the passivation layer 140 is patterned to expose the first opening 142 and the second type semiconductor pattern 130a exposing the electrode region 112 of the first type semiconductor pattern 110a. A second opening 144 is formed to partially expose the top surface of the. The first opening 142 and the second opening 144 may be formed by a conventional photolithography process. For example, a photoresist film (not shown) is formed on the passivation layer 140. Thereafter, a photoresist pattern (not shown) may be formed to selectively expose a region where the first opening and the second opening are to be formed through a normal exposure and development process. Subsequently, the protective pattern 140a may be formed by etching the protective layer 140 using the photoresist pattern.

5 and 6, the transparent electrode film 150 is formed on the entire surface of the light emitting structure 123 including the first opening 142 and the second opening 144. For example, the transparent electrode film 150 may be an indium tin oxide (ITO) film. For example, the transparent electrode film 150 may be formed to have the same thickness as the passivation layer 140 or may be formed thicker than the passivation layer 140. The transparent electrode film 150 may have a thickness of about 1000 to 3000Å. If the transparent electrode film 150 is thinner, it is difficult to serve as an electrode, and if the transparent electrode film 150 is thicker, only a process delay is caused.

Referring to FIG. 7, a mask pattern 160 covering the first opening and the second opening is formed on the transparent electrode film 150. For example, the mask pattern 160 may be a photoresist pattern or a conventional hard mask. As described above, the mask pattern 160 may be formed by a conventional photolithography process.

Referring to FIG. 8, the transparent electrode film 150 is patterned using the mask pattern 160. By the patterning, a first electrode 150a filling the first opening 142 and a second electrode 150b filling the second opening 144 are simultaneously formed. Therefore, the first electrode 150a and the second electrode 150b may include the same material. As such, the present invention can improve process efficiency by simultaneously forming the first electrode and the second electrode.

In general, patterning by anisotropic etching is performed to form the first electrode and the second electrode. Therefore, even when the first electrode and the second electrode are completed, a material forming a transparent electrode film, for example, ITO residue, may remain on the side surface of the light emitting structure. In the case where the ITO residue remains, a leakage current may occur when the light emitting diode is operated. However, according to the present invention, since the passivation layer is formed on the light emitting structure, electrical defects such as leakage current may be prevented from occurring even if the patterning of the electrodes is not perfect in the process.

Referring to FIG. 9, metal electrodes 170a and 170b may be further formed on the first electrode and the second electrode. For example, the metal electrode may include chromium or / and gold.

In the method of manufacturing a light emitting diode of the present invention, after a protective film including an insulating material is formed on the surface of the light emitting structure, the protective film is patterned, and all the electrodes connected to the positive and negative terminals are formed as transparent electrodes. Therefore, by simultaneously forming electrodes, process efficiency can be improved, and even if the patterning is not perfect, deterioration of electrical characteristics can be prevented by the protective film.

Claims (7)

Forming a light emitting structure including a first type semiconductor layer, a light emitting active layer exposing the first type semiconductor layer, and a second type semiconductor layer on a substrate; Forming a passivation layer covering the light emitting structure and having a first opening and a second opening exposing the first type semiconductor layer and the second type semiconductor layer, respectively; And And simultaneously forming first and second electrodes in contact with the first type semiconductor layer and the second type semiconductor layer, respectively, in the first and second openings. The method of claim 1, Forming the protective film is: Conformally forming an insulating film on the light emitting structure; And And selectively patterning the insulating layer to expose the second type semiconductor layer and a part of the first type semiconductor layer. The method of claim 1, Forming the first and second electrodes includes: Forming a transparent electrode film on the passivation layer including the first and second openings; Forming a mask pattern on the transparent electrode film having the first and second openings; Etching the exposed transparent electrode film using the mask pattern; And The method of manufacturing a light emitting diode comprising the step of removing the mask pattern. The method of claim 3, wherein The transparent electrode film is a manufacturing method of a light emitting diode, characterized in that the ITO film. The method of claim 1, The protective film is a method of manufacturing a light emitting diode comprising a silicon oxide. The method of claim 1, Wherein said first type is n-type and said second type is p-type. The method of claim 1, And forming a metal electrode connected to each of the first electrode and the second electrode.

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