TWI398015B - Method for manufacturing light-emitting diode - Google Patents

Description

Method for manufacturing light emitting diode

The present invention relates to a method of fabricating a light emitting diode (LED), and more particularly to a method of fabricating a light emitting diode having a reusable growth substrate.

Generally, a metal substrate nitride (III-Nitride) light-emitting diode is formed by first epitaxial growth on a growth substrate composed of sapphire or a semiconductor, and then bonding the light-emitting epitaxial structure to the metal substrate by bonding. Then, the growth substrate is stripped from the light-emitting epitaxial structure to complete the fabrication of the light-emitting diode.

In the process of fabricating a metal substrate nitride light-emitting diode, after the growth substrate of the light-emitting diode epitaxial wafer is removed, the grown substrate can no longer be used. As a result, in the process of the metal substrate light-emitting diode, a large number of used growth substrates will become one of the important factors that cannot be reduced in the mass production of the metal substrate light-emitting diode products. Therefore, it will result in waste of resources and a large amount of waste, which is inconsistent with economic benefits and environmental protection needs.

Accordingly, it is an object of the present invention to provide a method of fabricating a light-emitting diode which cleans a grown substrate which is peeled off from an epitaxial structure by dry, wet, or in combination with dry and wet etching. The cleaned growth substrate can be recycled for use in the next epitaxial structure growth. Therefore, the consumption of the growth substrate can be saved, the environment is environmentally friendly and the cost is reduced, and the economic benefit can be greatly improved.

According to the above object of the present invention, a method for fabricating a light emitting diode includes at least: providing a growth substrate; forming a first light emitting diode on the growth substrate, wherein the step of forming the first light emitting diode comprises at least Forming a first buffer layer on the growth substrate; forming a first luminescent epitaxial structure on the first buffer layer; forming a first metal substrate on the first luminescent epitaxial structure; and stripping the growth substrate, The first light emitting epitaxial structure is exposed; a cleaning step is performed on the grown substrate; and a second light emitting diode is formed on the growth substrate.

According to a preferred embodiment of the present invention, when the cleaning step described above is performed, a dry etching method, a wet etching method, a mechanical polishing method or a high temperature baking method can be used.

In order to make the description of the present invention more detailed and complete, reference is made to the following description in conjunction with the drawings of Figures 1 through 5.

Please refer to FIG. 1 to FIG. 3 , which are cross-sectional views showing a process of a light emitting diode according to a preferred embodiment of the present invention. First, a growth substrate 100 is provided, wherein the material of the growth substrate 100 can be, for example, sapphire, gallium arsenide, indium phosphide or gallium phosphide. A light-emitting diode is formed on the growth substrate 100. When the light emitting diode is fabricated, the buffer layer 102 is formed on the surface of the growth substrate 100 by, for example, low temperature epitaxy. The material of the buffer layer 102 may be, for example, aluminum nitride or gallium nitride. Next, a light-emitting epitaxial structure is grown on the buffer layer 102 by, for example, an organometallic vapor deposition epitaxy method, a liquid phase epitaxy method, or a molecular beam epitaxy method. In the exemplary embodiment, the luminescent epitaxial structure includes a first electrical semiconductor layer 104, a first electrical confinement layer 106, an active layer 108, and a second electrical confinement layer 110, which are sequentially stacked on the surface of the buffer layer 102, and The second electrical contact layer 112, wherein the first electrical property and the second electrical property are different electrical properties. When the first electrical property is N-type, the second electrical property is P-type; and when the first electrical property is P-type, the second electrical property is N-type. In the exemplary embodiment, the first electrical property is an N-type, and the second electrical property is a P-type. In an embodiment, the material of the first electrical semiconductor layer 104 may be, for example, aluminum gallium indium nitride [(Al _x Ga _{1 - x} ) _y In _{1 - y} N; 0≦x≦1, 0≦y≦1 The material of the first electrical confinement layer 106 may be, for example, aluminum gallium indium nitride [(Al _x Ga _{1 - x} ) _y In _{1 - y} N; 0≦x≦1, 0≦y≦1], active layer 108 may be a double heterostructure or a multiple quantum well structure, and the material of the active layer 108 may, for example, comprise aluminum gallium indium nitride [(Al _x Ga _{1 - x} ) _y In _{1 - y} N; 0≦x≦1,0≦ Y≦1], the material of the second electrical confinement layer 110 may be, for example, aluminum gallium indium nitride [(Al _x Ga _{1 - x} ) _y In _{1 - y} N; 0≦x≦1, 0≦y≦1] The material of the second electrical contact layer 112 may be, for example, aluminum gallium indium nitride [(Al _x Ga _{1 - x} ) _y In _{1 - y} N; 0≦x≦1, 0≦y≦1].

Then, the metal substrate 120 may be directly formed on the second electrical contact layer 112 of the luminescent epitaxial structure, or the luminescent epitaxial structure may be selectively processed, for example, defining a pattern of the luminescent epitaxial structure, and/or Additional structural layers, such as transparent electrodes and metal reflective layers, are additionally formed on the second electrical contact layer 112 of the luminescent epitaxial structure. In the exemplary embodiment, the luminescent epitaxial structure is first patterned by using, for example, lithography and etching or dicing techniques to remove a portion of the second electrical contact layer 112, a portion of the second electrical confinement layer 110, and a portion. The active layer 108 and a portion of the first electrical confinement layer 106 form a trench 122 in the luminescent epitaxial structure, wherein the trench exposes a portion of the first electrical semiconductor layer 104. When the trench 122 is formed in the luminescent epitaxial structure, a dry etching method, a wet etching method, or a mechanical cutting polishing method can be utilized. Next, a dielectric protective layer 118 is formed on the sidewalls and the bottom surface of the trench 122 by, for example, deposition or coating to protect portions of the luminescent epitaxial structure exposed by the trench 122. The material of the dielectric protective layer 118 may be a high dielectric organic material, an oxide containing germanium, or a nitride containing germanium, such as hafnium oxide or tantalum nitride.

The second electrically transparent electrode 114 is formed on the second electrical contact layer 112 by using, for example, thermal evaporation (E-beam Evaporation), electron beam evaporation (Epoxy Evaporation) or ion sputtering (Sputtering). The current dispersion effect, wherein the material of the second electrically transparent electrode 114 can be, for example, indium tin oxide, indium oxide, tin oxide, zinc oxide or magnesium oxide. Subsequently, a metal reflective layer 116 is formed on the second electrically transparent electrode 114 by, for example, thermal evaporation, electron beam evaporation, or ion sputtering to reflect the light emitted from the active layer 108 toward the metal reflective layer 116. The material of the metal reflective layer 116 may be, for example, gold, aluminum, silver, platinum, chromium, nickel or an alloy of these metals. Next, the metal substrate 120 is formed on the exposed portion of the dielectric protective layer 118, the second electrically transparent electrode 114, and the exposed portion of the metal reflective layer 116 by, for example, electroplating or deposition, and fills the trench 122 to form, for example, The structure shown in Figure 1. The material of the metal substrate 120 may be, for example, copper, molybdenum, nickel, gold, silver, platinum, aluminum, or an alloy of these metals.

After the production of the metal substrate 120 is completed, the growth substrate 100 is peeled off from the light-emitting epitaxial structure by, for example, a laser stripping method or a difference in heating stress. When the growth substrate 100 is separated from the luminescent epitaxial structure, part of the buffer layer 102 is removed, and another portion of the buffer layer 102 may remain on the surface of the growth substrate 100, as shown in FIG. The buffer layer 102a on the substrate 100. After the growth substrate 100 is peeled off, the first electrical semiconductor layer 104 of the light-emitting epitaxial structure is exposed.

After the growth substrate 100 is stripped, the first electrical electrode 124 is formed on the exposed first electrical semiconductor layer 104 by, for example, deposition. The material of the first electrical electrode 124 may be, for example, a conductive metal oxide, or may be titanium, aluminum, gold or an alloy of these metals. Next, the first electrical electrode pad 126 is formed on the first electrical electrode 124 by, for example, deposition, and the fabrication of the light-emitting diode 128 is completed. The material of the first electrical electrode pad 126 may be, for example, titanium, aluminum, gold or an alloy of these metals.

Please refer to FIG. 4 and FIG. 5 , which are cross-sectional views showing a cleaning process of a growth substrate according to a preferred embodiment of the present invention. As shown in FIG. 4, after the growth substrate 100 is peeled off, the buffer layer 102a and other contaminants may remain on the surface of the growth substrate 100. At this time, the growth substrate 100 may be subjected to a cleaning step to remove the buffer layer 102a and other contaminants remaining on the surface of the growth substrate 100, so that the growth substrate 100 can be fabricated for the next light-emitting diode. When the substrate 100 is cleaned, a dry etching method, a wet etching method, a mechanical polishing method, or a high temperature baking method may be employed. When dry etching is used, reactive ion etching (RIE) or inductively coupled plasma ion etching (ICP) can be used. In an example of a dry etching process, a chlorine gas series gas can be used to clean the growth substrate 100. When the wet etching method is used, the growth substrate 100 can be cleaned by using hot nitric acid or potassium hydroxide as an etching liquid. Polishing pads and polishing fluids can be used when using mechanical grinding. When the high-temperature baking method is utilized, the residue remaining on the growth substrate 100, such as the buffer layer 102a and some contaminants, is cracked by high temperature, and the residue after the cracking is removed. The cleaned substrate 100, as shown in Fig. 5, can be reused for fabrication on the next light-emitting diode.

According to the preferred embodiment of the present invention, one of the advantages of the present invention is that the manufacturing method of the light-emitting diode of the present invention is cleaned from the epitaxial structure by means of dry, wet, or dry and wet etching. The grown substrate is peeled off. The cleaned growth substrate can be recycled for use in the next epitaxial structure growth. Therefore, the consumption of the growth substrate can be saved, the environment is environmentally friendly and the cost is reduced, and the economic benefit can be greatly improved.

Although the present invention has been described above in terms of a preferred embodiment, it is not intended to limit the invention, and it is intended that various modifications may be made without departing from the spirit and scope of the invention. And the scope of the present invention is defined by the scope of the appended claims.

100. . . Growth substrate

102. . . The buffer layer

102a. . . The buffer layer

104. . . First electrical semiconductor layer

106. . . First electrical limitation layer

108. . . Active layer

110. . . Second electrical localization layer

112. . . Second electrical contact layer

114. . . Second electrically transparent electrode

116. . . Metal reflective layer

118. . . Dielectric protective layer

120. . . Metal substrate

122. . . ditch

124. . . First electrical electrode

126. . . First electrical electrode pad

128. . . Light-emitting diode

1 to 3 are cross-sectional views showing a process of a light emitting diode according to a preferred embodiment of the present invention.

4 to 5 are cross-sectional views showing a cleaning process of a growth substrate in accordance with a preferred embodiment of the present invention.

100. . . Growth substrate

102a. . . The buffer layer

104. . . First electrical semiconductor layer

106. . . First electrical limitation layer

108. . . Active layer

110. . . Second electrical localization layer

112. . . Second electrical contact layer

114. . . Second electrically transparent electrode

116. . . Metal reflective layer

118. . . Dielectric protective layer

120. . . Metal substrate

122. . . ditch

Claims (54)

A method for manufacturing a light emitting diode includes at least: providing a growth substrate; forming a first light emitting diode on the growth substrate, wherein the step of forming the first light emitting diode comprises at least: forming a first buffer Laminating on the growth substrate; forming a first luminescent epitaxial structure on the first buffer layer; forming a first metal substrate on the first luminescent epitaxial structure; and stripping the growth substrate to expose The first light emitting epitaxial structure; wherein a residue comprises at least a portion of the remaining first buffer layer on the growth substrate; removing the residue on the growth substrate; and forming a second light emitting diode Growing on the substrate. The method for manufacturing a light-emitting diode according to claim 1, wherein the material of the growth substrate is sapphire, gallium arsenide, indium phosphide or gallium phosphide. The method for manufacturing a light-emitting diode according to claim 1, wherein the material of the first buffer layer is aluminum nitride or gallium nitride. The method for manufacturing a light-emitting diode according to claim 1, wherein the step of forming the first buffer layer utilizes a low temperature epitaxy method. The method for manufacturing a light-emitting diode according to claim 1, wherein the step of forming the first light-emitting epitaxial structure is performed by an organometallic vapor deposition epitaxy method, a liquid phase epitaxy method or a molecule Beam epitaxy. The method for manufacturing a light-emitting diode according to the first aspect of the invention, wherein the first light-emitting epitaxial structure comprises at least one of the first electrical semiconductor layers sequentially stacked on the first buffer layer, a first An electrical limiting layer, an active layer, a second electrical limiting layer, and a second electrical contact layer, and the first electrical property and the second electrical property are different electrical properties. The method for manufacturing a light-emitting diode according to claim 6, wherein the material of the first electrical semiconductor layer is aluminum gallium indium nitride [(Al _x Ga _1-x ) _y In _1-y N; 0≦x≦1,0≦y≦1]; the material of the first electrical confinement layer is aluminum gallium indium nitride [(Al _x Ga _1-x ) _y In _1-y N; 0≦x≦1, 0≦y≦1]; the active layer has a double heterostructure or a multiple quantum well structure, and the material of the active layer comprises aluminum gallium indium nitride [(Al _x Ga _1-x ) _y In _1-y N; 0≦x≦1,0≦y≦1]; the material of the second electrical confinement layer is aluminum gallium indium nitride [(Al _x Ga _1-x ) _y In _1-y N; 0≦x≦1, 0≦y≦1]; and the material of the second electrical contact layer is aluminum gallium indium nitride [(Al _x Ga _1-x ) _y In _1-y N; 0≦x≦1,0≦y≦1 ]. The method for manufacturing the light-emitting diode according to claim 6, wherein the step of forming the first light-emitting epitaxial structure and the step of forming the first metal substrate further comprises: forming a trench in the a portion of the first electrically conductive semiconductor layer is exposed in the first luminescent epitaxial structure; and a dielectric protective layer is formed over the sidewalls and the bottom surface of the trench. The method for manufacturing a light-emitting diode according to claim 8, wherein the step of forming the trench is performed by a dry etching method, a wet etching method or a mechanical cutting grinding method. The method for manufacturing a light-emitting diode according to claim 8, wherein the material of the dielectric protective layer is selected from the group consisting of a cerium-containing oxide, a cerium-containing nitride, and a high dielectric organic material. One group. The method for producing a light-emitting diode according to claim 8, wherein the material of the dielectric protective layer is germanium dioxide or tantalum nitride. The method for manufacturing a light-emitting diode according to claim 8, wherein at least the step of forming the dielectric protective layer and the step of forming the first metal substrate further comprises forming a second electrically transparent electrode. The second electrical property On the contact layer. The method for manufacturing a light-emitting diode according to claim 12, wherein the material of the second electrically transparent electrode is selected from the group consisting of indium tin oxide, indium oxide, tin oxide, zinc oxide, and magnesium oxide. One group. The method for manufacturing a light-emitting diode according to claim 12, further comprising forming a metal reflective layer between the step of forming the second electrically transparent electrode and the step of forming the first metal substrate On the second electrically transparent electrode. The method for producing a light-emitting diode according to claim 14, wherein the material of the metal reflective layer is selected from the group consisting of gold, aluminum, silver, platinum, chromium, nickel, and alloys thereof. The method for manufacturing a light-emitting diode according to claim 14, wherein the first electrical localization layer is an N-type, and the second electrical localization layer is a P-type. The method for manufacturing a light-emitting diode according to claim 16, wherein the step of forming the first light-emitting diode further comprises at least a step of stripping the grown substrate to form a first electrical electrode for exposure. And forming a first electrical electrode on the portion of the first electrical electrode. The method for manufacturing a light-emitting diode according to claim 17, wherein the material of the first electrical electrode is selected from the group consisting of titanium, aluminum, gold and alloys thereof. The method for manufacturing a light-emitting diode according to claim 17, wherein the material of the first electrical electrode is a conductive metal oxide. The method for manufacturing a light-emitting diode according to claim 17, wherein the material of the first electrical electrode pad is selected from the group consisting of titanium, aluminum, gold and alloys thereof. The method for manufacturing a light-emitting diode according to claim 1, wherein the step of forming the first metal substrate is performed by an electroplating method or a deposition method. The method for manufacturing a light-emitting diode according to claim 1, wherein the material of the first metal substrate is selected from the group consisting of copper, molybdenum, nickel, gold, silver, platinum, aluminum, and alloys thereof. a group of people. The method for manufacturing a light-emitting diode according to claim 1, wherein the step of stripping the grown substrate is performed by a laser stripping method or a heating stress difference method. The method for manufacturing a light-emitting diode according to claim 1, wherein the step of removing the residue on the growth substrate is performed by a dry etching method, a wet etching method, a mechanical polishing method or a High temperature drying method. The method for manufacturing a light-emitting diode according to claim 24, wherein the dry etching method is a reactive ion etching technique (RIE) or an inductively coupled plasma ion etching technique (ICP). The method for producing a light-emitting diode according to claim 24, wherein the dry etching method uses a chlorine gas. The method for producing a light-emitting diode according to claim 24, wherein the wet etching method uses hot nitric acid or potassium hydroxide. The method for producing a light-emitting diode according to claim 24, wherein the mechanical polishing method uses a polishing pad and a polishing liquid. The method for producing a light-emitting diode according to claim 24, wherein the high-temperature baking method uses high temperature to cleave the residue remaining on the growth substrate. A method for manufacturing a light-emitting diode, comprising at least: Providing a growth substrate; forming a first light-emitting diode on the growth substrate, wherein the step of forming the first light-emitting diode comprises: forming a first buffer layer on the growth substrate; forming a first The illuminating epitaxial structure is disposed on the first buffer layer, wherein the first luminescent epitaxial structure comprises at least one of the first electrical semiconductor layer, a first electrical limiting layer, and the first electrically stratified layer. An active layer, a second electrical limiting layer, and a second electrical contact layer, and the first electrical property and the second electrical property are different electrical properties; forming a trench in the first light emitting epitaxial structure to be exposed a portion of the first electrical semiconductor layer; forming a dielectric protective layer covering the sidewalls and the bottom surface of the trench; forming a second electrically transparent electrode on the second electrical contact layer; forming a metal reflective layer Forming a first metal substrate on the metal reflective layer; and stripping the growth substrate to expose the first electrical semiconductor layer; wherein a residue comprises at least a portion of the remaining first Buffer layer in the Over the length of the substrate; removing the residue on the growth substrate; and forming a second light-emitting diode on the growth substrate. The method for manufacturing a light-emitting diode according to claim 30, wherein the material of the growth substrate is sapphire, gallium arsenide, indium phosphide or gallium phosphide. The method for manufacturing a light-emitting diode according to claim 30, wherein the material of the first buffer layer is aluminum nitride or gallium nitride. The method for manufacturing a light-emitting diode according to claim 30, wherein the step of forming the first buffer layer utilizes a low temperature epitaxy method. The method for manufacturing a light-emitting diode according to claim 30, wherein the step of forming the first light-emitting epitaxial structure is performed by an organometallic vapor deposition epitaxy method, a liquid phase epitaxy method or a molecule. Beam epitaxy. The method for manufacturing a light-emitting diode according to claim 30, wherein the material of the first electrical semiconductor layer is aluminum gallium indium nitride [(Al _x Ga _1-x ) _y In _1-y N; 0≦x≦1,0≦y≦1]; the material of the first electrical confinement layer is aluminum gallium indium nitride [(Al _x Ga _1-x ) _y In _1-y N; 0≦x≦1, 0≦y≦1]; the active layer has a double heterostructure or a multiple quantum well structure, and the material of the active layer comprises aluminum gallium indium nitride [(Al _x Ga _1-x ) _y In _1-y N; 0≦x≦1,0≦y≦1]; the material of the second electrical confinement layer is aluminum gallium indium nitride [(Al _x Ga _1-x ) _y In _1-y N; 0≦x≦1, 0≦y≦1]; and the material of the second electrical contact layer is aluminum gallium indium nitride [(Al _x Ga _1-x ) _y In _1-y N; 0≦x≦1,0≦y≦1 ]. The method for manufacturing a light-emitting diode according to claim 30, wherein the step of forming the trench is performed by a dry etching method, a wet etching method or a mechanical cutting grinding method. The method for manufacturing a light-emitting diode according to claim 30, wherein the material of the dielectric protective layer is selected from the group consisting of a cerium-containing oxide, a cerium-containing nitride, and a high dielectric organic material. One group. The method for producing a light-emitting diode according to claim 30, wherein the material of the dielectric protective layer is germanium dioxide or tantalum nitride. The method for manufacturing a light-emitting diode according to claim 30, wherein the material of the second electrically transparent electrode is selected from the group consisting of indium tin oxide, indium oxide, tin oxide, zinc oxide, and magnesium oxide. One group. The method for producing a light-emitting diode according to claim 30, wherein the material of the metal reflective layer is selected from the group consisting of gold, aluminum, silver, platinum, chromium, nickel, and alloys thereof. The manufacturer of the light-emitting diode according to claim 30 of the patent application scope The method, wherein the first electrical limiting layer is an N-type, and the second electrical limiting layer is a P-type. The method for manufacturing a light-emitting diode according to claim 41, wherein the step of forming the first light-emitting diode further comprises at least a step of stripping the grown substrate to form a first electrical electrode for exposure. And forming a first electrical electrode on the portion of the first electrical electrode. The method for manufacturing a light-emitting diode according to claim 42, wherein the material of the first electrical electrode is selected from the group consisting of titanium, aluminum, gold and alloys thereof. The method for manufacturing a light-emitting diode according to claim 42, wherein the material of the first electrical electrode is a conductive metal oxide. The method for manufacturing a light-emitting diode according to claim 42, wherein the material of the first electrical electrode pad is selected from the group consisting of titanium, aluminum, gold and alloys thereof. The method for manufacturing a light-emitting diode according to claim 30, wherein the step of forming the first metal substrate is performed by an electroplating method or a deposition method. The method for manufacturing a light-emitting diode according to claim 30, wherein the material of the first metal substrate is selected from the group consisting of copper, molybdenum, nickel, gold, silver, platinum, aluminum, and alloys thereof. a group of people. The method for manufacturing a light-emitting diode according to claim 30, wherein the step of stripping the grown substrate utilizes a laser stripping method or a heating stress difference method. The method for manufacturing a light-emitting diode according to claim 30, wherein the step of removing the residue on the growth substrate is performed by a dry etching method, a wet etching method, a mechanical polishing method, or A high temperature drying method. The method for manufacturing a light-emitting diode according to claim 49, wherein the dry etching method is a reactive ion etching technique or an inductively coupled plasma ion etching technique. The method for producing a light-emitting diode according to claim 49, wherein the dry etching method uses a chlorine gas. The method for producing a light-emitting diode according to claim 49, wherein the wet etching method uses hot nitric acid or potassium hydroxide. The manufacturer of the light-emitting diode according to claim 49 of the patent application scope The method wherein the mechanical grinding method uses a polishing pad and a polishing liquid. The method for producing a light-emitting diode according to claim 49, wherein the high-temperature baking method uses high temperature to crack the residue remaining on the growth substrate.