TWI636587B - Light-emitting diode structure for avoiding light leakage on side and back sides and manufacturing method thereof - Google Patents

Abstract

The present invention is a light-emitting diode structure and a manufacturing method thereof for avoiding light leakage on the side and the back surface, and the structure comprises a non-transparent layer, a sapphire substrate, an N-type semiconductor layer, a light-emitting layer and a P-type stacked in sequence. The semiconductor layer and a photoresist layer surrounding the sapphire substrate are formed by sequentially forming the N-type semiconductor layer, the light-emitting layer and the P-type semiconductor layer on the sapphire substrate, and then thinning the sapphire from the back surface The thickness of the substrate is then covered by the non-transmissive layer, and finally the photoresist layer surrounding the sapphire substrate is formed around the sapphire substrate. According to the present invention, the present invention covers the non-transmissive layer, thins the sapphire substrate, and sets the photoresist. The layer can be completely shielded from the side and back of the sapphire substrate to solve the problem of light leakage of the sapphire substrate.

Description

Light-emitting diode structure for avoiding light leakage on side and back sides and manufacturing method thereof

The invention relates to a light-emitting diode structure, in particular to a light-emitting diode structure for avoiding light leakage on the side and the back surface and a manufacturing method thereof.

Light Emitting Diode (LED) is mainly formed by multiple epitaxial crystallization of a luminescent semiconductor material, taking a blue light emitting diode as an example. It is mainly composed of a gallium nitride-based (GaN-based) epitaxial film, and is stacked to form a light-emitting body having a sandwich structure in which the main structure includes an N-type semiconductor layer, a light-emitting layer, and a P-type semiconductor layer.

With the evolution of the light-emitting structure, the micro-light-emitting diode (Micro LED) is a new generation of display technology, such as China National Publication No. CN13400849A, China Public Publication No. CN103400918B, US Publication No. US8573469B2, and US Publication No. US7598149B2. The micro-light-emitting diode has display characteristics with self-illumination, and has a relatively simple structure, no light-consuming component (filter), and has low power consumption and high brightness to solve the current power consumption and brightness of the display. The display structure of the micro-light-emitting diode is to miniaturize the structure of the light-emitting diode into a single individual, and the size thereof is generally about 10 micrometers, and then the miniaturized light-emitting diodes are transferred in batch and array onto the circuit substrate. The circuit substrate has a circuit structure required for driving the micro-light-emitting diodes, and the circuit substrate can be a hard, soft transparent, opaque substrate, etc., and the array structure can be used to drive the arrayed light-emitting diodes to emit light.

Each of the light-emitting diodes emits a single color of light, so that different light-emitting diode materials can be selected to emit different colors of light, and then mixed to form a color display, and the basic structure of the micro-light-emitting diode is two. The polar body, and thus its structure is as shown in US7598149B2, which is usually formed by crystal growth on a sapphire substrate. However, the sapphire substrate is a light-transmissive material which is prone to light leakage.

That is to say, when a single light-emitting diode is lit, the sapphire substrate that is transmitted to the bottom will be laterally guided to the surrounding light-emitting diode, causing a slight phenomenon at the bottom of the unlit light-emitting diode. It causes mutual interference between two adjacent light-emitting units. Therefore, the conventional micro-light-emitting diode affects the display contrast and color accuracy of the micro-light-emitting diode due to light leakage of the sapphire substrate, and obviously there is room for improvement.

Accordingly, the main object of the present invention is to disclose a light-emitting diode structure that avoids light leakage from the side and back surfaces and a method of fabricating the same.

The structure of the present invention comprises a non-transmissive layer, a sapphire substrate, an N-type semiconductor layer, a light-emitting layer, a P-type semiconductor layer and a photoresist layer surrounding the sapphire substrate, wherein the sapphire substrate is fixed to the non-transparent layer. The N-type semiconductor layer, the light-emitting layer and the P-type semiconductor layer are sequentially formed on the sapphire substrate, and the photoresist layer and the non-transmissive layer completely cover the side surface and the back surface of the sapphire substrate.

The method for manufacturing a light emitting diode structure includes the steps of sequentially forming the N-type semiconductor layer, the light-emitting layer and the P-type semiconductor layer on the sapphire substrate, and then thinning the thickness of the sapphire substrate from the back surface. Then, the sapphire substrate is fixed on the non-transparent layer, and finally the photoresist layer surrounding the sapphire substrate is formed around the sapphire substrate.

Accordingly, the present invention can completely shield the side surface and the back surface of the sapphire substrate by providing the non-transmissive layer, thinning the sapphire substrate, and providing the photoresist layer. The light emitted by the light-emitting layer does not escape from the sapphire. The side surface and the back surface of the substrate leak out, and the problem of light leakage at the sapphire substrate can be completely solved.

The detailed description of the present invention and the technical description of the present invention are further illustrated by the accompanying drawings, but it should be understood that these embodiments are merely illustrative and not to be construed as limiting.

Please refer to FIG. 1A, FIG. 1B and FIG. 1C. The present invention is a light-emitting diode structure for avoiding leakage of light from the side and the back, comprising a non-transmissive layer 10, a sapphire substrate 20, and a light-emitting diode. An N-type semiconductor layer 31, a light-emitting layer 32 and a P-type semiconductor layer 33 and a photoresist layer 40 surrounding the sapphire substrate 20, and for the sake of convenience in drawing, only the light-emitting diodes of the 3*3 matrix arrangement are drawn. The top view structure of the body.

In order to provide a forward voltage to the sandwich structure of the N-type semiconductor layer 31, the light-emitting layer 32 and the P-type semiconductor layer 33, the present invention further provides an N-type electrode 34, a P-type electrode 35, and an isolation of the N-type electrode. A transparent conductive layer 37 is further disposed on the P-type semiconductor layer 33 and is electrically connected to the P-type electrode 35 for diffusing current. In order to protect the overall structure, a protective layer 70 (shown in FIG. 1B) may be formed on the outermost surface of the overall structure to avoid structural damage caused by external forces.

Please refer to FIG. 2A to FIG. 2F and FIG. 3A to FIG. 3J. The manufacturing process of the present invention is first to prepare the sapphire substrate 20 for the epitaxial process, and the surface thereof is completely stacked. The P-type semiconductor layer 33 (shown in FIG. 3A) is then etched on the sapphire substrate 20 to form the N-type semiconductor layer 31, the light-emitting layer 32 and the P-type semiconductor layer 33 (eg, FIG. 2A). The pattern shown in Fig. 3B).

Then, the thickness of the sapphire substrate 20 is reduced from the back surface (as shown in FIG. 2B), and the method of thinning the thickness of the sapphire substrate 20 is relatively diverse, such as an etching process or a polishing process, etc., as long as it can be effective. The sapphire substrate 20 can be removed.

The non-transmissive layer 10 is then covered on the sapphire substrate 20 . In practice, the non-transmissive layer 10 includes a bonding layer 50 and a carrier 51 . The sapphire substrate 20 can be fixed to the carrier 51 through the bonding layer 50 . When the carrier 51 is opaque, the adhesive layer 50 may optionally comprise a transparent, opaque bonding material; and when the carrier 51 is transparent, the bonding layer 50 An opaque bonding material should be used. That is, at least one of the carrier 51 and the adhesive layer 50 is opaque. The material of the carrier 51 includes, but is not limited to, bismuth (Si), gallium arsenide (GaAs), copper (Cu), tungsten copper (CuW), tungsten molybdenum (MoW), molybdenum (Mo), nickel (Ni), aluminum. (Al), silver (Ag), chromium (Cr), titanium (Ti), cobalt (Co), iron (Fe), gold (Au), tungsten (W), alumina (Al ₂ O ₃ ), nitriding Aluminum (AlN), zinc oxide (ZnO), gallium oxide (Ga ₂ O ₃ ), beryllium oxide (BeO), boron nitride (BN), tantalum carbide (SiC), germanium dioxide (SiO ₂ ) and boron nitride (BN). The bonding layer 50 includes, but is not limited to, a polymer adhesive, a bonding metal, and the like.

Then, the photoresist layer 40 surrounding the sapphire substrate 20 is formed around the sapphire substrate 20. The photoresist layer 40 may be made of black rubber or other opaque materials, such as BCB (Benzocyclobutene) and Jujube. Any one of an amine (Polyimide) such that the photoresist layer 40 and the non-transmissive layer 10 completely cover the side and bottom surfaces of the sapphire substrate 20.

In the method of fabrication, the photoresist layer 40 can be formed by directly sintering the sapphire substrate 20 using a laser. Alternatively, the photoresist layer 40 may be formed by a removal process to form a trench 60 surrounding the sapphire substrate 20 (as shown in FIG. 2D and FIG. 3C). The removal process may be selected from etching and cutting. Alternatively, after the trench 60 is formed, the transparent conductive layer 37 (shown in FIG. 3D) may be formed on the P-type semiconductor layer 33, and then a reflective layer 65 may be overlaid on the N-type semiconductor layer 31. And the side of the trench 60 (as shown in FIG. 2E and FIG. 3E), the reflective layer 65 may be selected from a Bragg reflector layer (DBR) and an Omni-directional reflectors (ODR). Either to avoid the possibility of side leakage, while increasing the light reflectivity.

Then, the photoresist layer 40 is formed on the trench 60 (as shown in FIG. 2E and FIG. 3F), and the photoresist layer 40 is formed here, and the material selection of the photoresist layer 40 is selected. For example, when the photoresist layer 40 is black rubber, it can be directly filled in the trench 60. When the photoresist layer 40 is an opaque coating material, the sputtering or evaporation method is used. deal with. In addition, for the convenience of manufacturing and the effect of enhancing the photoresist, the trench 60 may penetrate into the non-transmissive layer 10, that is, the photoresist layer 40 may penetrate the non-transmissive layer 10 to achieve a better photoresist effect.

Next, the N-type electrode 34 (shown in FIG. 3G), the barrier layer 36 (shown in FIG. 3H) and the P-type electrode 35 are formed (as shown in FIG. 2F and FIG. 3I). Finally, the protection layer 70 is set up (as shown in FIG. 1B and FIG. 3J) to complete the process.

In summary, the advantages of the present invention include at least:

1. The present invention completely covers the side and the back surface of the sapphire substrate through the photoresist layer and the non-transmissive layer, and the light emitted by the PN junction light emitting structure is not The side surface and the back surface of the sapphire substrate are leaked, and the problem of light leakage at the sapphire substrate can be completely solved.

2. The photoresist layer can be formed by laser sintering the sapphire substrate, and is a single process program, which can reduce the manufacturing cost.

3. The thickness of the sapphire substrate is reduced from the back surface, which not only reduces the overall thickness, but also reduces the area of light leakage, thereby reducing the possibility of light leakage.

The above are only the preferred embodiments of the present invention and are not intended to limit the scope of the embodiments of the present invention. That is, the equivalent changes and modifications made by the scope of the patent application of the present invention are covered by the scope of the invention.

10‧‧‧ non-transparent layer

20‧‧‧Sapphire substrate

31‧‧‧N type semiconductor layer

32‧‧‧Lighting layer

33‧‧‧P type semiconductor layer

34‧‧‧N type electrode

35‧‧‧P type electrode

36‧‧‧Barrier

37‧‧‧Transparent conductive layer

40‧‧‧Light barrier

50‧‧‧bonded layer

51‧‧‧ Carrier Board

60‧‧‧ trench

65‧‧‧reflective layer

70‧‧‧Protective layer

1A is a top plan view of a structure of a light emitting diode of the present invention. Fig. 1B is a cross-sectional view showing the structure of a broken line 1B-1B of Fig. 1A of the present invention. Fig. 1C is a cross-sectional view showing the structure of a broken line 1C-1C of Fig. 1A of the present invention. 2A-2F are cross-sectional views showing the structure of a light-emitting diode structure drawing process. 3A-3J are top structural views of the fabrication process of the light-emitting diode structure diagram.

Claims (6)

An illuminating diode structure for preventing leakage of light from side and back surfaces, comprising: a non-transmissive layer; a sapphire substrate, the sapphire substrate is fixed on the non-transparent layer; an N-type semiconductor layer; a luminescent layer; a semiconductor layer, the N-type semiconductor layer, the luminescent layer and the P-type semiconductor layer are sequentially formed on the sapphire substrate; and a photoresist layer surrounding the sapphire substrate, the photoresist layer and the non-transparent layer are completely covered The photoresist layer is formed on the side and the back surface of the sapphire substrate by sintering the sapphire substrate by laser. An illuminating diode structure for preventing leakage of light from side and back surfaces, comprising: a non-transmissive layer; a sapphire substrate, the sapphire substrate is fixed on the non-transparent layer; an N-type semiconductor layer; a luminescent layer; a semiconductor layer, the N-type semiconductor layer, the luminescent layer and the P-type semiconductor layer are sequentially formed on the sapphire substrate; and a photoresist layer surrounding the sapphire substrate, the photoresist layer and the non-transparent layer are completely covered The photoresist layer is formed on the side surface and the back surface of the sapphire substrate by using a removal process to form a trench surrounding the sapphire substrate, and the photoresist layer is formed on the trench. The removal process is selected from the group consisting of etching and cutting. Any one of the photoresist layers is a black gel. The light-emitting diode structure for avoiding leakage of the side surface and the back surface, as described in claim 2, wherein the N-type semiconductor layer and the side of the trench are covered with a reflective layer, and the reflective layer is selected from the group consisting of a Bragg reflector layer and a whole Any of the reflective layers. A method for manufacturing a light-emitting diode structure for preventing light leakage of a side surface and a back surface, the light-emitting diode structure comprising: a non-transmissive layer; a sapphire substrate, the sapphire substrate is fixed on the non-transmissive layer; and an N-type semiconductor layer a light-emitting layer; a P-type semiconductor layer, the N-type semiconductor layer, the light-emitting layer and the P-type semiconductor layer are sequentially formed on the sapphire substrate; and a photoresist layer surrounding the sapphire substrate, the photoresist layer Forming the side surface and the back surface of the sapphire substrate completely with the non-transmissive layer, the method comprising: forming the N-type semiconductor layer, the light-emitting layer and the P-type semiconductor layer on the sapphire substrate, and then thinning the back surface a thickness of the sapphire substrate, the sapphire substrate is then fixed on the non-transmissive layer, and finally the photoresist layer surrounding the sapphire substrate is formed around the sapphire substrate, and the photoresist layer is sintered by using a laser to sapphire substrate And formed. A method for manufacturing a light-emitting diode structure for preventing light leakage of a side surface and a back surface, the light-emitting diode structure comprising: a non-transmissive layer; a sapphire substrate, the sapphire substrate is fixed on the non-transmissive layer; and an N-type semiconductor layer a light-emitting layer; a P-type semiconductor layer, the N-type semiconductor layer, the light-emitting layer and the P-type semiconductor layer are sequentially formed on the sapphire substrate; and a photoresist layer surrounding the sapphire substrate, the photoresist layer Forming the side surface and the back surface of the sapphire substrate completely with the non-transmissive layer, the method comprising: forming the N-type semiconductor layer, the light-emitting layer and the P-type semiconductor layer on the sapphire substrate, and then thinning the back surface The thickness of the sapphire substrate is then fixed on the opaque layer, and finally the photoresist layer surrounding the sapphire substrate is formed around the sapphire substrate, and the photoresist layer is formed by a removal process. surround The trench of the sapphire substrate further forms the photoresist layer in the trench, and the removing process is any one selected from the group consisting of etching and cutting. The manufacturing method of claim 5, wherein a front side of the N-type semiconductor layer and the trench is covered with a reflective layer, the reflective layer is selected from a Bragg reflector layer and before the photoresist layer is formed. Any of the omnidirectional reflective layers.