TWI478378B - Led and method of manufacturing the same - Google Patents

Description

Light-emitting diode and manufacturing method thereof

The present invention relates to a light emitting diode and a method of manufacturing the same.

Typically, the light emitting diode comprises a substrate and a single epitaxial structure grown on the substrate. Since the epitaxial structure is a whole piece of growth, as the epitaxial structure grows, the epitaxial structure accumulates excessive stress and breaks. Therefore, it is necessary to provide a luminescence capable of reducing the stress accumulation problem in epitaxial growth. Diode.

In view of the above, it is necessary to provide a light-emitting diode capable of reducing stress accumulation during epitaxial growth and a method of manufacturing the same.

A light-emitting diode includes a substrate and a plurality of epitaxial structures grown on the substrate, the epitaxial structures being not connected to each other to reduce stress accumulation during epitaxial growth.

A method for manufacturing a light-emitting diode, comprising the steps of: providing a substrate; fabricating a patterned barrier layer region on one surface of the substrate by using lithography; and oxidizing or nitriding the barrier layer region to a portion of the substrate corresponding to the barrier layer region is oxidized or nitrided to form a barrier layer; An epitaxial structure is grown on the surface of the substrate, and the epitaxial structure does not grow at the barrier layer such that a plurality of epitaxial structures that are not connected to each other are formed on the surface of the substrate.

Compared with the prior art, the light-emitting diode of the present invention grows a plurality of mutually unconnected epitaxial structures on the substrate to reduce stress accumulation caused by growing a whole epitaxial structure on the substrate.

100‧‧‧Substrate

101‧‧‧Block area

102‧‧‧ epitaxial structure

103‧‧‧Transparent conductive layer

104‧‧‧ trench

105‧‧‧Insulation protection layer

106‧‧‧Electrical connection layer

107‧‧‧N type electrode

108‧‧‧P type electrode

109‧‧‧Block

110, 20‧‧‧ upper surface

120‧‧‧ photoresist layer

130‧‧‧Photomask

140‧‧‧lower surface

1 is a partially enlarged side elevational view of a light emitting diode according to an embodiment of the present invention.

Figure 2 is a plan view of Figure 1.

Figure 3 is a side elevation, partially enlarged view of a substrate coated with a layer of photoresist.

Figure 4 is a plan view of the reticle.

Fig. 5 is a plan view of the substrate and the photoresist after development.

Fig. 6 is a side elevational view, partly in elevation, of the substrate and the photoresist after development.

Figure 7 is a side elevational view, partially enlarged, of the substrate and photoresist after oxidation or nitridation.

Figure 8 is a side elevational, partially enlarged view of the photoresist removed from the oxidized or nitrided substrate.

Figure 9 is a side elevational view, partially enlarged, of a plurality of epitaxial structures grown on a substrate.

Figure 10 is a side elevational, partially enlarged view of the transparent conductive layer formed on the epitaxial structure.

Figure 11 is a side elevational view, partially enlarged, of the transparent conductive layer between adjacent epitaxial structures.

Fig. 12 is a partially enlarged side elevational view showing the insulating protective layer formed on the epitaxial structure.

The invention will be further described in detail below with reference to the accompanying drawings.

Referring to FIGS. 1 and 2, a light emitting diode according to an embodiment of the present invention includes a substrate 100, a plurality of epitaxial structures 102 grown on the upper surface 110 of the substrate 100, and transparent conductive layers formed on the upper surfaces of the respective epitaxial structures 102. The layer 103 and the N-type electrode 107 formed on the lower surface 140 of the substrate 100. The epitaxial structures 102 are not connected to each other. The transparent conductive layer 103 may be made of a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), or aluminum zinc oxide (AZO).

A trench 104 is formed between two adjacent epitaxial structures 102. The grooves 104 constitute a mesh structure. The substrate 100 is exposed outside the epitaxial structure 102 corresponding to the trench 104. The substrate 100 is oxidized or nitrided at a position corresponding to the trench 104 to form a barrier layer 109. The trench 104 is filled with an insulating material to form an insulating protective layer 105 to insulate the adjacent epitaxial structure 102 and the transparent conductive layer 103 on the adjacent epitaxial structure 102.

A plurality of electrical connection layers 106 are disposed at the intersection of the epitaxial structures 102 to electrically connect the transparent conductive layers 103 on the epitaxial structures 102, and the epitaxial structures 102 are connected in parallel. As long as the transparent conductive layers 103 on the surfaces of the respective epitaxial structures 102 are electrically connected together, the electrical connection layer 106 can be arranged according to actual needs. In this embodiment, the plurality of electrical connection layers 106 are uniformly disposed on the mesh nodes of the mesh structure composed of the trenches 104. Specifically, an electrical connection layer 106 is disposed at the intersection of each of the four epitaxial structures 102. The electrical connection layer 106 on each epitaxial structure 102 is only two and is located at a diagonal.

Four P-type electrodes 108 are formed at four corners of the entire light emitting diode. When the four P-type electrodes 108 and the N-type electrodes 107 are respectively connected by wire bonding, the plurality of epitaxial structures 102 are connected in parallel with each other. In the present embodiment, four P-type electrodes 108 are provided in the four corners of the entire light-emitting diode in order to make the entire light-emitting diode more conductive.

At present, the general size of high-power light-emitting diodes is 1×1mm2, and the maximum size is up to 1.5 x 1.5 mm2. The size of the light-emitting diode composed of the plurality of epitaxial structures 102 of the present invention is comparable to the general size of the current light-emitting diode.

The method of manufacturing the above-described light-emitting diode includes the following steps:

1. Referring to FIG. 3-6, a patterned barrier layer region 101 is formed on one of the upper surfaces 110 of the substrate 100 by lithography. The specific steps are: 1) coating a photoresist on the upper surface 110 of the substrate 100. The layer 120. 2) provides a mask 130. Since the photoresist of the photoresist layer 120 in the embodiment is a negative photoresist, the area of the photoresist layer 120 corresponding to the barrier layer region 101 is covered, and other regions are covered. It should be exposed outside of the reticle 130 to allow other areas to receive light. In other embodiments, the photoresist of the photoresist layer 120 may be a positive photoresist. In this case, a region of the photoresist layer 120 corresponding to the barrier region 101 is exposed outside the photomask 130 to receive the region. Illumination, while other areas are covered by the reticle 130 and are not exposed to light. 3) The light is irradiated onto the photoresist layer 120 through the reticle 130, and the light-receiving light-receiving light energy is chemically changed, and the pattern formed by the reticle 130 is transferred to the photoresist layer 120 on the upper surface of the substrate 100. This step is exposure. In this embodiment, the light used is ultraviolet light. 4) The photomask 130 is removed, and the substrate 100 is immersed in the developing solution. For the positive photoresist, the illuminated region is dissolved during development, and for the negative photoresist, the unexposed region is dissolved. In summary, a patterned barrier layer region 101 is formed on the photoresist layer 120 after development. In this embodiment, the substrate 100 is an n-type conductive germanium substrate. In other embodiments, the substrate 100 can be other substrates of n-type conductivity, such as a tantalum carbide substrate or a gallium nitride substrate.

2. Referring to FIG. 7, the barrier layer region 101 is oxidized so that the substrate 100 not coated with the photoresist is oxidized to SiO2 to form a barrier layer 109 to prevent subsequent growth of the epitaxial structure on the barrier layer 109. In other embodiments, the barrier layer region 101 may be subjected to a nitridation process such that the substrate 100 not coated with the photoresist is nitrided into Si3N4. A barrier layer 109 is formed to prevent subsequent growth of the epitaxial structure on the barrier layer 109.

3. Referring to FIG. 8 at the same time, the photoresist layer 120 on the upper surface 110 of the substrate 100 is removed.

4. Referring to FIG. 9 simultaneously, a plurality of epitaxial structures 102 are grown on the surface 110 of the substrate 100. In order to avoid the lateral growth of the respective epitaxial structures 102 and connect the adjacent epitaxial structures 102 together, it is necessary to ensure that the epitaxial structures 102 are separated by a thickness D greater than 2 times the epitaxial structure, that is, the barrier layer 109. The width d is greater than 2 times the thickness D of the epitaxial structure 102, that is, d>2D. In the present embodiment, the width d of the barrier layer 109 is 10 um. The epitaxial structure 102 can be grown by Chemical Vapor Deposition (CVD) or Molecular Beam Epitaxy (MBE). Since the barrier layer 109 prevents the growth of the epitaxial structure 102, a trench 104 is formed between the adjacent two epitaxial structures 102.

5. Referring to FIG. 10 at the same time, the transparent conductive layer 103 is grown on the upper surface 20 of the LED. Then, the transparent conductive layer 103 at the trench 104 is etched away by dry etching, as shown in FIG. 11, so that the transparent conductive layer 103 is grown on the surface of each epitaxial structure 102.

6. Referring to FIG. 12 at the same time, the insulating protective layer 105 is evaporated in the trench 104. In the embodiment, the insulating protective layer 105 does not fill the entire trench 104. It can be understood that in other embodiments, the insulating protective layer 105 can fill the entire trench 104.

7. Referring again to FIG. 1-2, after the above steps, the electrical connection layer 106 is vapor-deposited at the intersection of the epitaxial structures 102 to electrically connect the transparent conductive layer 103 on the upper surface 20 of the light-emitting diode. In this embodiment, the electrical connection layer 106 is disposed at the intersection of each of the four epitaxial structures 102, and the electrical connection layer 106 on each of the epitaxial structures 102 is only two and located at a diagonal. Then, at the four corners of the entire light-emitting diode Four P-type electrodes 108 are formed on the four epitaxial structures 102. In this embodiment, the electrical connection layer 106 may be made of a metal material such as gold or nickel.

8. The bottom of the substrate 100 is ground to grind the substrate 100 to a desired thickness, and then the lower surface 140 of the substrate 100 is polished. A metal film is vapor-deposited on the lower surface 140 of the substrate 100 after polishing to serve as an N-type electrode 107.

After the above steps, the light-emitting diode shown in Figure 1-2 is completed.

Compared with the prior art, the light-emitting diode of the present invention grows a plurality of epitaxial structures 102 on the substrate 100 at intervals to reduce stress accumulation caused by growing a whole epitaxial structure on the substrate 100.

It is to be understood that those skilled in the art can make various other changes and modifications in accordance with the technical concept of the present invention, and all such changes and modifications should fall within the protection scope of the present invention.

100‧‧‧Substrate

102‧‧‧ epitaxial structure

103‧‧‧Transparent conductive layer

105‧‧‧Insulation protection layer

106‧‧‧Electrical connection layer

107‧‧‧N type electrode

109‧‧‧Block

110‧‧‧ upper surface

140‧‧‧lower surface

Claims (7)

A light-emitting diode comprising a substrate and a plurality of epitaxial structures grown on the substrate, the epitaxial structures being not connected to each other to reduce stress accumulation during epitaxial growth, the epitaxial Channels are formed between the structures, and the substrate is exposed to the epitaxial structure corresponding to the trenches, wherein the trenches are filled with an insulating material, and each of the epitaxial structures forms a transparent conductive layer. The trenches form a network structure, and a plurality of electrical connection layers are uniformly disposed on the mesh nodes of the mesh structure to electrically connect the transparent conductive layers formed on the adjacent epitaxial structures. The light-emitting diode of claim 1, wherein the substrate forms a barrier layer corresponding to the trench to prevent the epitaxial structure from growing at the barrier layer. The light-emitting diode according to claim 2, wherein the barrier layer is formed by oxidizing or nitriding the substrate. The light-emitting diode according to claim 1, wherein the interval between the epitaxial structures is greater than 2 times the thickness of the epitaxial structure. A method for manufacturing a light-emitting diode, comprising the steps of: providing a substrate; fabricating a patterned barrier layer region on one surface of the substrate by using lithography; and oxidizing or nitriding the barrier layer region to A portion of the substrate corresponding to the barrier layer region is oxidized or nitrided to form a barrier layer; an epitaxial structure is grown on the surface of the substrate, and the epitaxial structure does not grow at the barrier layer such that a plurality of mutually non-connected surfaces are formed on the surface of the substrate An epitaxial structure, a trench is formed between the epitaxial structures, the substrate is exposed outside the epitaxial structure corresponding to the trench; a transparent conductive layer is formed on the surface of each epitaxial structure; The trench is filled with an insulating material to insulate adjacent epitaxial structures and the adjacent epitaxial structures The transparent conductive layer is provided with a plurality of electrical connection layers on the mesh nodes of the mesh structure formed by the trenches to electrically connect the transparent conductive layers formed on the adjacent epitaxial structures. The method for manufacturing a light-emitting diode according to claim 5, wherein the barrier layer has a width greater than 2 times the thickness of the epitaxial structure. The method for manufacturing a light-emitting diode according to claim 5, further comprising the step of etching away the transparent conductive layer grown at the trench.