CN114256391A

CN114256391A - Manufacturing method of display substrate, display substrate and display device

Info

Publication number: CN114256391A
Application number: CN202111578344.7A
Authority: CN
Inventors: 李辉; 张珂
Original assignee: Shenzhen Stan Technology Co Ltd
Current assignee: Shenzhen Stan Technology Co Ltd
Priority date: 2021-12-22
Filing date: 2021-12-22
Publication date: 2022-03-29

Abstract

The disclosure provides a manufacturing method of a display substrate, the display substrate and a display device. The manufacturing method of the display substrate comprises the following steps: arranging a plurality of light-emitting units on a substrate, exposing a part of a first semiconductor layer, wherein the light-emitting units form a table board; a first light blocking structure is arranged in a groove between the table surfaces of the light emitting units; arranging electrode layers on the light emitting unit and the first semiconductor layer to obtain a Micro-LED array; bonding the Micro-LED array with a circuit substrate, and peeling off the substrate. By applying the technical scheme, the light blocking structure is arranged between the light emitting units, the light crosstalk phenomenon between the light emitting units can be effectively avoided, and the display effect of the display substrate is improved.

Description

Manufacturing method of display substrate, display substrate and display device

Technical Field

The disclosure relates to the technical field of LEDs, in particular to a manufacturing method of a display substrate, the display substrate and a display device.

Background

Micro-LED (Micro Light Emitting diode) is a new self-luminous display technology, and has advantages in brightness, resolution, contrast, energy consumption, service life, response speed and thermal stability compared with LCD and OLED due to the characteristics of small size, high integration and self-luminous of Micro-LED chip.

However, since the Micro-LED chips are small in size, the size of a single Micro-LED chip is usually in the range of several to several tens of micrometers, and the pitch between the Micro-LED chips is smaller, usually smaller than the size of a single Micro-LED chip, how to prevent the crosstalk between the Micro-LED chips becomes a difficult problem.

Disclosure of Invention

In order to solve the technical problems mentioned in the background art, the present disclosure provides a method for manufacturing a display substrate, a display substrate and a display device.

According to a first aspect of the embodiments of the present disclosure, a method for manufacturing a display substrate is provided, where the method includes: arranging a plurality of light-emitting units on a substrate, exposing a part of a first semiconductor layer, wherein the light-emitting units form a table board; a first light blocking structure is arranged in a groove between the table surfaces of the light emitting units; arranging electrode layers on the light emitting unit and the first semiconductor layer to obtain a Micro-LED array; bonding the Micro-LED array with a circuit substrate, and peeling off the substrate. The light blocking structure is arranged between the light emitting units, so that the light crosstalk phenomenon between the light emitting units can be effectively avoided, and the display effect of the display substrate is improved.

Optionally, the disposing a first light blocking structure in a groove between the mesas of the light emitting unit includes: arranging photoresist on the surfaces of the light-emitting units, and exposing and removing the photoresist in the grooves; arranging a light blocking material on the surface of the photoresist, wherein the groove is filled with the light blocking material; and removing the residual photoresist and the light-blocking material on the residual photoresist to obtain the first light-blocking structure.

Optionally, the disposing a first light blocking structure in a groove between the mesas of the light emitting unit includes: and arranging black photoresist on the surfaces of the light-emitting units, exposing and removing the black photoresist outside the grooves, and only keeping the black photoresist in the grooves to form the first light-blocking structure.

Optionally, the method further comprises: arranging a second light-blocking structure on one side, far away from the circuit substrate, of the first semiconductor layer of the Micro-LED array; and an accommodating area is formed between the second light blocking structures. According to the embodiment of the disclosure, the light blocking structures are arranged on the two sides of the first semiconductor layer, so that the light blocking effect is further improved, light crosstalk between the Micro-LED chips is effectively prevented, and the display effect of the display substrate is further improved.

Optionally, the second light blocking structures are arranged in one-to-one correspondence with the first light blocking structures.

Optionally, the disposing a second light blocking structure on a side of the first semiconductor layer of the Micro-LED array away from the circuit substrate includes: arranging a light blocking material on one side of the first semiconductor layer, which is far away from the circuit substrate; arranging photoresist on one side of the light-blocking material, which is far away from the first semiconductor layer, and exposing and removing the photoresist at the corresponding position of the light-emitting unit; and removing the light-blocking material which is not covered by the photoresist, and removing the residual photoresist to obtain the second light-blocking structure.

Optionally, the disposing a second light blocking structure on a side of the first semiconductor layer of the Micro-LED array away from the circuit substrate includes: and arranging black photoresist on one side of the first semiconductor layer of the Micro-LED array, which is far away from the circuit substrate, exposing and removing the black photoresist outside the region corresponding to the groove, and only reserving the black photoresist in the region corresponding to the groove to form a second light blocking structure.

Optionally, the method further comprises: and a light reflecting layer is arranged on the side wall of the second light blocking structure. The light emitted by the Micro-LED chip and irradiated on the side wall of the second light-blocking structure is reflected by the reflecting layer and then emitted, so that the light intensity of the Micro-LED chip towards the light emitting direction can be improved, and the display effect of the display substrate is improved.

Optionally, the method further comprises: a light conversion material is disposed within the containment region.

Optionally, the light conversion material comprises quantum dots.

Optionally, the quantum dots include red quantum dots, green quantum dots, and blue quantum dots, and the red quantum dots, the green quantum dots, and the blue quantum dots are arranged in the accommodating area according to a preset arrangement rule.

Optionally, the method further comprises: and arranging a protective layer on one side of the Micro-LED array, which is far away from the circuit substrate.

According to a second aspect of the embodiment of the present disclosure, a display substrate is further provided, where the display substrate includes a Micro-LED array, a circuit substrate, and a first light blocking structure, the Micro-LED array is bonded to the circuit substrate, the Micro-LED array includes a plurality of Micro-LED chips, and the first light blocking structure is disposed between the Micro-LED chips.

Optionally, the display substrate further includes a second light blocking structure disposed on a side of the first semiconductor layer of the Micro-LED array, which is far away from the circuit substrate.

Optionally, a light reflecting layer is disposed on a sidewall of the second light blocking structure.

Optionally, a light conversion material is disposed in the accommodating region formed between the second light blocking structures.

Optionally, the light conversion material comprises quantum dots.

Optionally, the display substrate further includes a protective layer disposed on a side of the Micro-LED array away from the circuit substrate.

Optionally, the display substrate is manufactured by using the manufacturing method of the display substrate according to the first aspect of the present disclosure.

According to a third aspect of the embodiments of the present disclosure, there is also provided a display device. The display device comprises the display substrate of the second aspect of the present disclosure.

By applying the technical scheme, the light blocking structure is arranged between the light emitting units, the light crosstalk phenomenon between the light emitting units can be effectively avoided, and the display effect of the display substrate is improved. Furthermore, according to the technical scheme, the second light blocking structure is arranged on the other side of the first semiconductor layer, so that the light blocking effect is further improved, light crosstalk between the Micro-LED chips is effectively prevented, and the display effect of the display substrate is further improved.

In addition, the technical scheme of the present disclosure adopts a 'common N pole' design, which effectively reduces the area of the epitaxial wafer occupied by the electrode, increases the light emitting area, and further improves the light emitting efficiency.

Drawings

The above and other objects, features and advantages of exemplary embodiments of the present disclosure will become readily apparent from the following detailed description read in conjunction with the accompanying drawings. Several embodiments of the present disclosure are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar or corresponding parts and in which:

fig. 1 is a flowchart illustrating a method of fabricating a display substrate according to one embodiment of the present disclosure;

2 a-2 f are schematic diagrams illustrating a fabrication process flow of a display substrate according to one embodiment of the present disclosure;

fig. 3 is a schematic view illustrating a structure of a display substrate according to one embodiment of the present disclosure.

Detailed Description

It should be noted that, in the present disclosure, the embodiments and features of the embodiments may be combined with each other without conflict. The present disclosure will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

Spatially relative terms, such as "above … …," "above … …," "above … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial relationship to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary term "above … …" can include both an orientation of "above … …" and "below … …". The device may also be oriented 90 degrees or at other orientations and the spatially relative descriptors used herein interpreted accordingly.

Exemplary embodiments according to the present disclosure will now be described in more detail with reference to the accompanying drawings. These exemplary embodiments may, however, be embodied in many different forms and should not be construed as limited to only the embodiments set forth herein. It is to be understood that these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art, in the drawings, the thicknesses of layers and regions are exaggerated for clarity, and the same devices are denoted by the same reference numerals, and thus the description thereof will be omitted.

The present disclosure provides a method of manufacturing a display substrate. Referring to fig. 1, fig. 1 is a flowchart illustrating a method of fabricating a display substrate according to one embodiment of the present disclosure. As shown in fig. 1, the method for manufacturing the display substrate includes the following steps S101 to S104:

step S101: providing a plurality of light emitting units on a substrate, exposing a portion of a first semiconductor layer;

step S102: arranging a first light blocking structure between the light emitting units;

step S103: arranging electrode layers on the light emitting unit and the first semiconductor layer to obtain a Micro-LED array;

step S104: bonding the Micro-LED array with a circuit substrate, and peeling off the substrate.

According to the technical scheme, the light blocking structure is arranged between the light emitting units, so that the light crosstalk phenomenon between the light emitting units can be effectively avoided, and the display effect of the display substrate is improved.

In step S101, a plurality of light emitting cells may be disposed on a substrate, exposing a portion of a first semiconductor layer.

According to the embodiment of the disclosure, a plurality of light emitting units are arranged on a substrate, and an epitaxial structure is grown on the substrate by an epitaxial growth method, and then the plurality of light emitting units are obtained by etching; or the standard epitaxial wafer is etched to obtain a plurality of light emitting units.

Specifically, the epitaxial layer is grown on the substrate by an epitaxial growth method, for example, an N-type semiconductor layer, a light emitting layer, and a P-type semiconductor layer may be sequentially grown on the substrate by any one of liquid phase epitaxy, metal organic vapor phase epitaxy, and molecular beam epitaxy, thereby obtaining an epitaxial structure. The substrate can be any one of a sapphire substrate, a silicon carbide substrate, a gallium arsenide substrate, an aluminum nitride substrate and a zinc oxide substrate, and the sapphire substrate is preferred in the embodiment of the disclosure. The sapphire substrate, namely the aluminum oxide substrate, has the advantages of good chemical stability, no absorption of visible light and the like, is low in price, mature in preparation technology, suitable for industrial mass production, and beneficial to reduction of the manufacturing cost of the display substrate.

The standard epitaxial wafer can be obtained by external collection, and preferably, the standard epitaxial wafer with the multiple quantum well structure comprises a substrate, an N-type semiconductor layer, the multiple quantum well structure and a P-type semiconductor layer which are sequentially stacked from bottom to top.

The epitaxial structure or the standard epitaxial wafer is etched to obtain a plurality of light emitting units, for example, the light emitting units may be disposed on the epitaxial structure or the standard epitaxial wafer according to a preset MESA pattern by using a photoresist as a mask, etched by using an Inductively Coupled Plasma (ICP) etching method, and removed by using a dry photoresist removal method or a photoresist removal liquid wet photoresist removal method to obtain a plurality of light emitting units, wherein the light emitting units form MESAs (MESA) and are arranged at equal intervals in an array form. Each light emitting unit comprises an N-type semiconductor layer, a light emitting layer (multi-quantum well structure) and a P-type semiconductor layer, a groove is formed between every two adjacent light emitting units, namely a groove is formed between the table boards of the light emitting units, and part of the N-type semiconductor layer (namely a first semiconductor layer) is exposed. It can be understood that, after the MESA etching, the first semiconductor layer (i.e., the N-type semiconductor layer) around the periphery of the light emitting cell array is exposed, so that an electrode layer is subsequently disposed on the exposed first semiconductor layer. The thickness of the remaining first semiconductor layer around the periphery of the light emitting unit array may be the same as the thickness of the remaining first semiconductor layer between the light emitting units, that is, the etching depth between the light emitting units is the same as the etching depth around the periphery.

It should be noted that the display substrate of the embodiment of the present disclosure employs a Micro-LED array, the size of each light emitting unit is in the range of several to several tens of micrometers, and the size of the groove between adjacent light emitting units is smaller than that of a single light emitting unit, and is typically 5-10 μm.

Preferably, when the epitaxial structure or the standard epitaxial wafer is etched, the etching depth extends to a position below an interface between the light emitting layer (the multiple quantum well structure) and the N-type semiconductor layer, namely, a part of the N-type semiconductor layer between adjacent light emitting units is etched and removed, and the plurality of light emitting units are connected through the remaining N-type semiconductor layer, so that the common N-pole can be realized, the overall assembly can be realized subsequently, and the trouble of transferring a single chip is avoided. The ratio of the thickness removed by etching to the residual thickness in the N-type semiconductor layer between the adjacent light-emitting units is 1:1-6:1, the thinner the residual thickness is, the better the light-cross-light-preventing effect achieved by the light-blocking structure is, but the larger the process difficulty coefficient is, the higher the manufacturing cost is, and the too thin residual N-type semiconductor layer may influence the connection between the light-emitting units. In the embodiment of the disclosure, 75% -85% of the N-type semiconductor layer is preferably removed by etching, that is, the ratio of the thickness of the etched N-type semiconductor layer between adjacent light emitting units to the thickness of the remaining N-type semiconductor layer is preferably 15-17: 3-5. Under this proportion, not only can make a plurality of luminescence units pass through N type semiconductor layer and connect to sharing N type electrode effectively reduces the area that the electrode occupied the epitaxial wafer, increase luminous area, improves luminous efficiency, can effectively avoid the cluster light through set up the structure of hindering light between the luminescence unit moreover, improves display substrate's display effect.

Referring to fig. 2a, a standard epitaxial wafer 100 includes a sapphire substrate 101, an N-GaN layer 102, a multiple quantum well structure 103, and a P-GaN layer 104; the standard epitaxial wafer 100 is etched to obtain a plurality of light-emitting units, the etching depth extends to the N-GaN layer, wherein the thickness ratio of the etched and removed N-GaN layer to the thickness of the rest N-GaN layer is 4:1, namely, 1/5 of the N-GaN layer is reserved below the groove (close to one side of the substrate) between the adjacent light-emitting units, the light-emitting units are connected through the N-GaN layer, the common electrode is arranged, the area of the epitaxial wafer occupied by the electrode is effectively reduced, the light-emitting area is increased, the light-emitting efficiency is improved, the light-blocking structure is arranged between the light-emitting units, the light crosstalk is effectively avoided, and the display effect of the display substrate is improved.

It should be noted that fig. 2a only shows a light emitting unit portion, and does not show the periphery of the light emitting unit. It should be understood that after etching, the N-GaN layer around the periphery of the light emitting cell array is exposed, so that an electrode layer is subsequently disposed on the exposed N-GaN layer. It should be understood that the number of the light emitting units shown in fig. 2a is merely exemplary and is not limited thereto.

In step S102, a first light blocking structure may be disposed between the light emitting units.

According to the embodiment of the present disclosure, in order to effectively avoid crosstalk between adjacent light emitting units, a first light blocking structure is disposed between the light emitting units. The light-blocking material adopted by the first light-blocking structure can be any suitable insulating material with good light-blocking performance, can be used as a light-blocking wall to avoid light crosstalk between adjacent light-emitting units, and can be used as a passivation layer to effectively divide each light-emitting unit.

Specifically, the first light blocking structure is disposed between the light emitting units, for example, the first light blocking structure may be obtained by using black photoresist as a light blocking material, or may be formed by filling a light blocking material in a groove of an adjacent light emitting unit, or may be obtained by coating.

The obtaining of the first light blocking structure by using a black photoresist as a light blocking material may specifically include: and arranging black photoresist on the surfaces of the light-emitting units, exposing and removing the black photoresist outside the grooves, and only keeping the black photoresist in the grooves to form the first light-blocking structure. In the embodiment of the disclosure, the first light blocking structure is prepared by directly adopting the black photoresist, the preparation process is simple, and the process cost is low.

In another mode, the obtaining of the first light blocking structure by coating may specifically include: coating the surface of the whole device with photoresist, then exposing the photoresist between the light-emitting units, and reserving the photoresist at the rest positions; coating the surface of the whole device with a light-blocking material, wherein grooves between the light-emitting units are filled with the light-blocking material; and cleaning the device to remove the residual photoresist on the device and the light blocking material on the photoresist. It is understood that the "device" described in the embodiments of the present disclosure refers to the epitaxial wafer or the semiconductor device including the light emitting cell array obtained in step S101. In the embodiment of the present disclosure, the light blocking material is preferably black glue (the main component may be epoxy resin, silicon gel, or silicone resin).

Alternatively, in the process of obtaining the first light blocking structure by coating, the photoresist may be exposed according to a preset electrode pattern, so that the photoresist with the preset electrode pattern is formed on the surface of the device after exposure, so that after the photoresist and the light-blocking material thereon are cleaned and removed, an opening pattern of a preset electrode pattern is obtained, which comprises first openings on the P-type semiconductor layer of each light-emitting unit, and a second opening located at the periphery of the light emitting unit array, wherein the top projection shapes of the first opening and the second opening can be set according to actual needs, for example, the shape of the top view projection of the first opening may be a circle, a square, a triangle, a pentagram, a hexagon, or the like, and the shape of the top view projection of the second opening may be a strip, or may be composed of a plurality of shapes such as a circle, a square, a triangle, a pentagram, or a hexagon; the second opening may be disposed around the periphery of the light emitting unit array, may be disposed on any two opposite sides of the periphery of the light emitting unit array, and may also be disposed on any one side of the periphery of the light emitting unit array, which is not particularly limited herein.

Referring to fig. 2b, a first light blocking structure 105 is disposed between the light emitting units, and the first light blocking structure 105 uses black glue to prevent light crosstalk between adjacent light emitting units and can also serve as a passivation layer to effectively partition each light emitting unit. A first opening 106 is formed between the first light blocking structures 105 for disposing a P-type electrode; meanwhile, a second opening (not shown) is formed at the periphery of the light emitting unit for disposing an N-type electrode.

Alternatively, in another embodiment, which is not shown, a passivation layer may be further disposed, and the passivation layer may be opened to expose a portion of the first semiconductor layer at the periphery of the light emitting cell array and/or a portion of the P-type semiconductor layer of the light emitting cell, so that an electrode layer may be disposed at the opening.

In step S103, an electrode layer may be disposed on the light emitting unit and the first semiconductor layer to obtain a Micro-LED array.

According to the embodiment of the disclosure, the electrode layers can be deposited on the light emitting unit and the exposed first semiconductor layer through a one-time deposition process and respectively used as the P-type electrode and the N-type electrode; the P-type electrode and the N-type electrode can also be deposited on the light-emitting unit and the exposed first semiconductor layer respectively through two deposition processes.

Specifically, the electrode layers are disposed on the light emitting units and the first semiconductor layer, and for example, the electrode materials may be evaporated onto the P-type semiconductor layer of the light emitting units and the exposed first semiconductor layer at the periphery of the light emitting unit array by methods such as electron beam evaporation, plasma sputtering, or thermal evaporation, so as to form P-type electrodes and common N-type electrodes corresponding to the light emitting units one to one. The electrode material may be one or more of titanium, aluminum, gold, chromium, nickel, platinum and other metals. The arrangement of the public N electrode effectively reduces the area of the epitaxial wafer occupied by the electrode, increases the light-emitting area and improves the light-emitting efficiency.

According to the embodiment of the disclosure, after the first light-blocking structures are arranged between the light-emitting units, the light-emitting units are isolated from each other by the first light-blocking structures, and then the electrode layers are arranged on the P-type semiconductor layers of the light-emitting units and can be arranged in the openings formed by the first light-blocking structures, so that the short circuit of the electrodes is effectively avoided.

Referring to fig. 2c, a P-type electrode 107 is disposed on the P-GaN layer 104 of the light emitting unit, and the P-type electrode 107 is disposed in the first opening 106, i.e., the P-type electrodes 107 are isolated from each other by the first light blocking structure 105, thereby effectively avoiding electrode short circuit; meanwhile, an N-type electrode (not shown in the figure) is arranged on the exposed N-GaN layer at the periphery of the light emitting unit to obtain the Micro-LED chip array 200, and the adjacent Micro-LED chips are isolated from each other by the first light blocking structure 105.

Alternatively, in another embodiment, not shown, a current diffusion layer may be deposited on the second semiconductor layer (i.e., the P-type semiconductor layer) of the light emitting cell before depositing the electrode layer, and the current diffusion layer may be a single metal layer, a multi-metal layer, an Indium Tin Oxide (ITO) layer, or the like, preferably using any one of a nickel/gold double-layer structure, an aluminum-based metal, and ITO. The arrangement of the current diffusion layer is beneficial to improving the uniformity of current and improving the photoelectric property of the display substrate.

Optionally, the current spreading layer may be annealed after deposition of the current spreading layer and before deposition of the electrode layer. Specifically, under the condition that the current diffusion layer is a nickel/gold double-layer structure metal layer, the wafer provided with the current diffusion layer is placed in N at the temperature of 550-580 DEG C₂Treating in gas environment for 4-6min, and placing in N₂And O₂Treating in mixed gas environment for 4-8min, wherein N₂And O₂The volume ratio of (3-5: 1), and finally carrying out rapid cooling; under the condition that the current diffusion layer is made of aluminum-based metal, the wafer provided with the current diffusion layer is placed in N at the temperature of 800-900 DEG C₂Treating in gas environment for 4-6 min; in the case that the current diffusion layer is ITO, the wafer provided with the current diffusion layer is placed at the temperature of 550-650 DEG C₂Treating for 200-400s in a gas environment to oxidize the ITO, and then placing the ITO at the temperature of 700-800 ℃ in N₂And treating for 25-35s in a gas environment to obtain the ITO alloy. By annealing the current diffusion layerThe treatment can further improve the conductivity of the current diffusion layer, so that the current diffusion layer and the P-type semiconductor layer realize ohmic contact; in addition, the annealing treatment can reduce the resistance of the N-type semiconductor layer, and is beneficial to improving the photoelectric performance of the display substrate.

It should be further noted that, in the embodiment of the present disclosure, the sequence of step S102 and step S103 may be interchanged, that is, a first light blocking structure is disposed between the light emitting units, and then electrode layers are disposed on the light emitting units and the first semiconductor layer; alternatively, it is possible to provide the electrode layers on the light emitting units and the first semiconductor layer, and then provide the first light blocking structure between the light emitting units.

For the case that the electrode layer is firstly arranged on the light emitting units and the first semiconductor layer, and then the first light blocking structure is arranged between the light emitting units, the electrode layer can also adopt an electrode structure comprising a P-type electrode, an N-type electrode and metal grid lines, wherein the metal grid lines are arranged between the light emitting units, the width of the metal grid lines is less than the width of grooves between the light emitting units and is about 3-5 μm; the arrangement of the P-type electrode and the N-type electrode can be the same as the above-mentioned arrangement, and the description thereof is omitted. The arrangement of the metal grid lines is beneficial to the current transmission of the light-emitting unit, further improves the current uniformity and improves the photoelectric performance of the display substrate.

Further, when the electrode layer adopts an electrode structure including three parts, namely a P-type electrode, an N-type electrode and metal grid lines, the first light blocking structure is arranged between the light emitting units and covers the metal grid lines.

It can be understood that, because the Micro-LED has a very small size, the size of the groove between the light emitting units is smaller, and if the light blocking structure is arranged after the electrode layer is prepared, the entrance of the groove between the light emitting units may be limited to be smaller due to the electrode layer, so that the light blocking material is not easy to enter the groove, or the groove cannot be filled, thereby affecting the light blocking effect. Therefore, the embodiment of the disclosure preferably sets the first light blocking structure and then prepares the electrode layer, but the embodiment of the disclosure is not limited to this.

In step S104, the Micro-LED array may be bonded to a circuit substrate, and the substrate may be peeled off.

According to embodiments of the present disclosure, the Micro-LED array may be bonded to the circuit substrate by any means known in the art, including but not limited to: arranging a bonding layer on the electrode layer, and bonding the Micro-LED array and the circuit substrate through the bonding layer; alternatively, the Micro-LED array is bonded to a bonding region of the circuit substrate.

The first method is preferably adopted in the embodiment of the present disclosure, that is, a bonding layer is disposed on the electrode layer, and the Micro-LED array is bonded to the circuit substrate through the bonding layer. Specifically, a passivation layer is deposited on the electrode layer by using a Plasma Enhanced Chemical Vapor Deposition (PECVD) method to protect the electrode layer, wherein the passivation layer may be made of silicon dioxide, silicon nitride, aluminum oxide, or other materials; then, etching an electrode contact hole on the passivation layer by adopting a dry etching and/or wet etching mode to expose part of the P-type electrode and the N-type electrode, wherein the position, the overlooking projection shape, the number and the like of the electrode contact hole can be set according to actual requirements, and are not particularly limited; and finally, depositing a bonding layer at the electrode contact hole by adopting a photoetching stripping method, wherein the bonding layer can adopt one or more of metals such as indium, titanium, aluminum, nickel, gold, chromium, platinum and the like.

Further, after the Micro-LED array is bonded with the circuit substrate, the substrate is peeled off. The substrate stripping method can adopt any one of the prior art, including but not limited to laser stripping, dry etching, wet etching and the like, and laser stripping is preferred.

As shown in fig. 2d, the Micro-LED chip array 200 is bonded to the circuit substrate 300 and the substrate is peeled off (not shown). It should be noted that, fig. 2d does not show the bonding portion of the peripheral N-type electrode of the Micro-LED chip array 200 and the circuit substrate 300, and it should be understood that the peripheral N-type electrode of the Micro-LED chip array 200 is also bonded to the circuit substrate 300. The number of Micro-LED chips in fig. 2d is merely exemplary and not limiting.

As a preferred embodiment, the method for manufacturing a display substrate further includes: arranging a second light-blocking structure on one side, far away from the circuit substrate, of the first semiconductor layer of the Micro-LED array; and an accommodating area is formed between the second light blocking structures.

According to the preferred embodiment of the disclosure, the light blocking structures are arranged on the two sides of the first semiconductor layer, so that the light blocking effect is further improved, light crosstalk between the Micro-LED chips is effectively prevented, and the display effect of the display substrate is further improved.

Preferably, the second light blocking structures and the first light blocking structures are arranged in a one-to-one correspondence manner, so that the light blocking structures are arranged around each Micro-LED chip and around the light emitting direction of each Micro-LED chip, light crosstalk between adjacent Micro-LED chips can be effectively avoided, light crosstalk between the Micro-LED chips after light emitting of the Micro-LED chips can be effectively avoided, and the display effect of the display substrate is obviously improved.

In an alternative embodiment, providing a second light blocking structure on a side of the first semiconductor layer of the Micro-LED array away from the circuit substrate may include: covering a light blocking material on the surface of one side, away from the circuit substrate, of the first semiconductor layer by adopting a die pressing or glue film process; coating a photoresist on the surface of the light-blocking material, and exposing the photoresist at the corresponding position of the Micro-LED chip; etching to remove the light-blocking material which is not covered by the photoresist; and cleaning and removing the residual photoresist to obtain second light-blocking structures, wherein an accommodating area is formed between every two adjacent light-blocking structures. Wherein, the second light-blocking structure preferably adopts black glue; the shape of the top view projection may be a grid shape, a strip shape, or a hole shape, and the cross-sectional shape may be a square shape or a trapezoid shape, which is not particularly limited herein.

In another alternative embodiment, the disposing a second light blocking structure on a side of the first semiconductor layer of the Micro-LED array away from the circuit substrate includes: arranging black photoresist on one side, far away from the circuit substrate, of the first semiconductor layer of the Micro-LED array, and exposing and removing the black photoresist outside the area corresponding to the groove; and only the black photoresist in the corresponding area of the groove is reserved to form the second light-blocking structures which are arranged in one-to-one correspondence with the first light-blocking structures. In the embodiment of the present disclosure, the width of the corresponding region of the groove may be the same as or slightly greater than the width of the groove.

Referring to fig. 2e, the second light blocking structures 108 are disposed on a side of the N-GaN layer 102 away from the circuit substrate 300, the second light blocking structures 108 are disposed in one-to-one correspondence with the first light blocking structures 105, and the accommodating regions 109 are formed between the second light blocking structures 108.

Note that, a portion of the peripheral N-type electrode of the Micro-LED chip array 200 bonded to the circuit substrate 300 is not shown in fig. 2 e. It should be understood that the number of Micro-LED chips in fig. 2e is merely exemplary and not limiting.

Optionally, when the second light-blocking structure is disposed, the first semiconductor layer and the circuit substrate may be coated with a light-blocking material, so that the display substrate may be protected by coating the side surface of the display substrate with the light-blocking material while the second light-blocking structure is obtained.

Further preferably, the method for manufacturing a display substrate further includes: and a light reflecting layer is arranged on the side wall of the second light blocking structure. The light reflecting layer can be made of a material with high reflectivity, for example, a metal such as aluminum and silver, and can be disposed on the side wall of the second light blocking structure facing the light emitting direction of the Micro-LED chip by any suitable method such as evaporation, sputtering or coating. The light emitted by the Micro-LED chip can be reflected by the reflective layer, so that the light emitting intensity of the Micro-LED chip towards the light emitting direction is improved, and the improvement of the light emitting performance of the display substrate is facilitated.

Further preferably, the method for manufacturing a display substrate further includes: a light conversion material is disposed within the containment region. And the light conversion material is used for converting monochromatic light emitted by the Micro-LED chip into light of other colors, so that color display can be realized. The light conversion material may be a phosphor or a quantum dot, preferably a quantum dot.

Preferably, the quantum dots may include red quantum dots, green quantum dots, and blue quantum dots, and the red quantum dots, the green quantum dots, and the blue quantum dots are disposed in the accommodating region according to a preset arrangement rule. For a full-color display substrate, when the Micro-LED chip emits blue light, the quantum dots may include red, green, and blue quantum dots or may include red, green, and colorless transparent fillers. Further, when the Micro-LED chip emits violet light, the quantum dots may include red, green, and blue quantum dots. Because every three Micro-LED chips can correspond to one pixel unit, the arrangement rules of quantum dots with different colors can be preset according to the arrangement of the Micro-LED chips and the pixel units, and then the quantum dots are correspondingly arranged in the accommodating area.

Further preferably, the method for manufacturing a display substrate further includes: and arranging a protective layer on one side of the Micro-LED array, which is far away from the circuit substrate. The protective layer may be any suitable transparent material for protecting the light conversion material and the array of Micro-LED chips.

Referring to fig. 2f, a reflective layer is disposed on the sidewall 110 of the second light blocking structure 108 facing the light emitting direction of the Micro-LED chip, a light conversion material 111 is disposed in the accommodating area 109, and a protective layer 112 is disposed on the side of the Micro-LED array 200 away from the circuit substrate 300. Wherein the light conversion material 111 comprises quantum dots.

Note that, a portion of the peripheral N-type electrode of the Micro-LED chip array 200 bonded to the circuit substrate 300 is not shown in fig. 2 f. It should be understood that the number of Micro-LED chips in fig. 2f is merely exemplary and not limiting.

According to the manufacturing method of the display substrate, the first light blocking structures are arranged between the light emitting units after the light emitting units are etched, so that the light blocking materials can be uniformly filled in the grooves between the light emitting units, the light crosstalk phenomenon between the light emitting units is effectively avoided, and the display effect of the display substrate is improved; the light-emitting units are connected through the first semiconductor layer, so that the light-emitting area is effectively increased, and the utilization rate of the epitaxial wafer is improved; furthermore, the second light blocking structure is arranged on the other side of the first semiconductor layer, so that light is further blocked around the light emitting direction of the Micro-LED chip, the light blocking effect is further improved, light crosstalk between the Micro-LED chip is effectively prevented, and the display effect of the display substrate is further improved.

The present disclosure also provides a display substrate. The display substrate can be manufactured by the manufacturing method of the display substrate or by any other suitable method.

As shown in fig. 3, the display substrate 400 includes a Micro-LED array 200, a circuit substrate 300, and a first light blocking structure 105, wherein the Micro-LED array 200 is bonded to the circuit substrate 300, the Micro-LED array 200 includes a plurality of Micro-LED chips, and the first light blocking structure 105 is disposed between the Micro-LED chips. The Micro-LED chip comprises an N-GaN layer 102, a multi-quantum well structure 103, a P-GaN layer 104 and a P-type electrode 107; the first light-blocking structure 105 may be made of any suitable insulating material with good light-blocking performance, and is preferably made of black glue.

According to the display substrate, the light blocking structures are arranged among the light emitting units, the light crosstalk phenomenon among the light emitting units is effectively avoided, and the display effect of the display substrate is improved.

Further, the display substrate 400 further includes a second light blocking structure 108, and the second light blocking structure 108 is disposed on a side of the N-GaN layer 102 of the Micro-LED array 200 away from the circuit substrate 300. The second light blocking structure 108 further improves the light blocking effect, effectively prevents light crosstalk between the Micro-LED chips, and further improves the display effect of the display substrate.

Furthermore, the second light blocking structures 108 and the first light blocking structures 105 are arranged correspondingly, that is, the second light blocking structures 108 and the first light blocking structures 105 are arranged on two opposite sides of the N-GaN layer 102, and the positions of the second light blocking structures and the first light blocking structures are in one-to-one correspondence, so that the second light blocking structures and the first light blocking structures define the light emitting direction of the Micro-LED chip together, the light crosstalk phenomenon is effectively avoided, the light crosstalk prevention of the Micro-LED with the Micro spacing is realized, and the display effect of the display substrate is improved.

Further, the thickness of the N-GaN layer between the second light blocking structure 108 and the first light blocking structure 105 accounts for 1/7-1/2, preferably 15% -25% of the total thickness of the N-GaN layer 102. Under this proportion, not only can make Micro-LED chip pass through N-GaN layer and connect to sharing N type electrode, effectively reduce the area that the electrode occupied the epitaxial wafer, increase light emitting area improves luminous efficiency, can effectively avoid the crosstalk between the Micro-LED chip through first light-blocking structure moreover, improves display substrate's display effect. More preferably, the thickness of the N-GaN layer between the second light blocking structure 108 and the first light blocking structure 105 accounts for 20% of the total thickness of the N-GaN layer 102.

Further, a reflective layer is disposed on a side wall 110 of the second light blocking structure facing the light emitting direction of the Micro-LED chip. The light emitted by the Micro-LED chip can be reflected by the reflective layer, so that the light emitting intensity of the Micro-LED chip towards the light emitting direction is improved, and the improvement of the light emitting performance of the display substrate is facilitated.

Further, a light conversion material 111 is disposed in the accommodation region 109 formed between the second light blocking structures 108, wherein the light conversion material includes quantum dots. The quantum dots comprise red quantum dots, green quantum dots and blue quantum dots, and the red quantum dots, the green quantum dots and the blue quantum dots are arranged in the accommodating area according to a preset arrangement rule. The light conversion material is used for converting monochromatic light emitted by the Micro-LED chip into light of other colors, so that color display can be realized. Because the light conversion material is arranged in the containing area formed between the second light blocking structures, the light converted by the light conversion material cannot generate the phenomenon of light crosstalk, and the full-color display effect of the display substrate is effectively improved. In addition, the arrangement of the reflecting layer on the side wall of the second light-blocking structure enables light emitted by the Micro-LED chip to be converted by the light conversion material and then reflected by the reflecting layer, so that the light-emitting intensity is effectively enhanced, and the display effect of the display substrate is further improved.

Further, the display substrate 400 further includes a protection layer 112, and the protection layer 112 is disposed on a side of the Micro-LED array 200 away from the circuit substrate 300. The protective layer may be any suitable transparent material for protecting the light conversion material 110 and the Micro-LED chip array 200.

It should be noted that, in a part not shown in fig. 3, the Micro-LED chip array 200 further includes an N electrode, which is a common electrode and is disposed at the periphery of the Micro-LED chip array 200, and the Micro-LED chips are connected to each other through the N-GaN layer 102 and electrically connected to the common N electrode; the common N electrode is bonded to the circuit substrate 300. It should be understood that the number of Micro-LED chips in fig. 3 is merely exemplary and not limiting.

According to the display substrate, the first light blocking structures are arranged among the light emitting units, so that the light crosstalk phenomenon among the light emitting units is effectively avoided, and the display effect of the display substrate is improved; the light-emitting units are connected through the first semiconductor layer, so that the light-emitting area is effectively increased, and the utilization rate of the epitaxial wafer is improved; furthermore, the second light blocking structure is arranged on the other side of the first semiconductor layer, so that light is further blocked around the light emitting direction of the Micro-LED chip, the light blocking effect is further improved, light crosstalk between the Micro-LED chip is effectively prevented, and the display effect of the display substrate is further improved.

The present disclosure also provides a display device. The display device comprises the display substrate, and the display substrate can comprise a Micro-LED chip array. The display device may be, for example, a display screen applied to an electronic apparatus. The electronic device may include: any equipment with a display screen, such as a smart phone, a smart watch, a notebook computer, a tablet computer, a vehicle event data recorder, a navigator and the like.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The above description is only a preferred embodiment of the present disclosure and is not intended to limit the present disclosure, and various modifications and changes may be made to the present disclosure by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. A method for manufacturing a display substrate, wherein the method comprises the following steps:

arranging a plurality of light-emitting units on a substrate, exposing a part of a first semiconductor layer, wherein the light-emitting units form a table board;

a first light blocking structure is arranged in a groove between the table surfaces of the light emitting units;

arranging electrode layers on the light emitting unit and the first semiconductor layer to obtain a Micro-LED array;

bonding the Micro-LED array with a circuit substrate, and peeling off the substrate.

2. The method of claim 1, wherein disposing a first light blocking structure in a recess between mesas of the light emitting cells comprises:

arranging photoresist on the surfaces of the light-emitting units, and exposing and removing the photoresist in the grooves;

arranging a light blocking material on the surface of the photoresist, wherein the groove is filled with the light blocking material;

and removing the residual photoresist and the light-blocking material on the residual photoresist to obtain the first light-blocking structure.

3. The method of claim 1, wherein disposing a first light blocking structure in a recess between mesas of the light emitting cells comprises:

and arranging black photoresist on the surfaces of the light-emitting units, exposing and removing the black photoresist outside the grooves, and only keeping the black photoresist in the grooves to form the first light-blocking structure.

4. The method of fabricating a display substrate of claim 1, wherein the method further comprises:

arranging a second light-blocking structure on one side, far away from the circuit substrate, of the first semiconductor layer of the Micro-LED array; and an accommodating area is formed between the second light blocking structures.

5. The method for manufacturing a display substrate according to claim 4, wherein the second light blocking structures are arranged in a one-to-one correspondence with the first light blocking structures.

6. The method for manufacturing the display substrate according to claim 5, wherein the step of providing the second light blocking structure on the side, away from the circuit substrate, of the first semiconductor layer of the Micro-LED array comprises the steps of:

arranging a light blocking material on one side of the first semiconductor layer, which is far away from the circuit substrate;

arranging photoresist on one side of the light-blocking material, which is far away from the first semiconductor layer, and exposing and removing the photoresist at the corresponding position of the light-emitting unit;

and removing the light-blocking material which is not covered by the photoresist, and removing the residual photoresist to obtain the second light-blocking structure.

7. The method for manufacturing the display substrate according to claim 5, wherein the step of providing the second light blocking structure on the side, away from the circuit substrate, of the first semiconductor layer of the Micro-LED array comprises the steps of:

and arranging black photoresist on one side of the first semiconductor layer of the Micro-LED array, which is far away from the circuit substrate, exposing and removing the black photoresist outside the region corresponding to the groove, and only reserving the black photoresist in the region corresponding to the groove to form the second light blocking structure.

8. The method of fabricating a display substrate of claim 4, wherein the method further comprises:

and a light reflecting layer is arranged on the side wall of the second light blocking structure.

9. The method of fabricating a display substrate of claim 4, wherein the method further comprises:

a light conversion material is disposed within the containment region.

10. The method of claim 9, wherein the light conversion material comprises quantum dots.

11. The manufacturing method of the display substrate according to claim 10, wherein the quantum dots comprise red quantum dots, green quantum dots and blue quantum dots, and the red quantum dots, the green quantum dots and the blue quantum dots are arranged in the accommodating area according to a preset arrangement rule.

12. The method of fabricating a display substrate of claim 1, wherein the method further comprises:

and arranging a protective layer on one side of the Micro-LED array, which is far away from the circuit substrate.

13. A display substrate comprises a Micro-LED array, a circuit substrate and a first light-blocking structure, wherein the Micro-LED array is bonded with the circuit substrate and comprises a plurality of Micro-LED chips, and the first light-blocking structure is arranged between the Micro-LED chips.

14. The display substrate of claim 13, wherein the display substrate further comprises a second light blocking structure disposed on a side of the first semiconductor layer of the Micro-LED array away from the circuit substrate.

15. The display substrate of claim 14, wherein the second light blocking structures are arranged in one-to-one correspondence with the first light blocking structures.

16. A display device, wherein the display device comprises the display substrate of any one of claims 13 to 15.