CN120152481A

CN120152481A - A light-emitting substrate, a display device and a manufacturing method

Info

Publication number: CN120152481A
Application number: CN202510293540.1A
Authority: CN
Inventors: 王珂; 曹占锋; 卢鑫泓; 齐琪; 曲燕; 梁志伟; 刘英伟; 薛大鹏; 王国强
Original assignee: BOE Technology Group Co Ltd
Current assignee: BOE Technology Group Co Ltd
Priority date: 2020-09-10
Filing date: 2020-09-10
Publication date: 2025-06-13
Also published as: CN114171661A; CN114171661B

Abstract

The present invention provides a light-emitting substrate, a display device and a manufacturing method, which relate to the field of display technology. The light-emitting substrate includes a binding area and a light-emitting area. The binding area includes a plurality of first pads, and the plurality of first pads are used to bind and connect with a circuit board; any one of the plurality of first pads includes a first metal sublayer and a first conductive sublayer stacked; the material of the first metal sublayer is a metal or a metal alloy; the first conductive sublayer has oxidation resistance and covers the first metal sublayer; the light-emitting area includes a plurality of second pads, and the plurality of second pads are used to bind and connect with a plurality of light-emitting units; the light-emitting substrate also includes a substrate, the first conductive sublayer is located on a side away from the substrate relative to the first metal sublayer, and the material of the first conductive sublayer includes a copper-nickel alloy, and the ratio of the copper-nickel alloy ranges from 70:30 to 95:5. The present invention is used to manufacture a light-emitting substrate.

Description

Light-emitting substrate, display device and manufacturing method

Technical Field

The present invention relates to the field of display technologies, and in particular, to a light emitting substrate, a display device, and a manufacturing method thereof.

Background

The Mini/Micro LED luminous substrate has higher requirements on the resistance of metal wiring, so copper metal is commonly used as wiring materials. In the manufacturing process of the light-emitting substrate, mini/Micro LED binding, flexible printed circuit board or integrated circuit binding are required to be carried out respectively.

Disclosure of Invention

The embodiment of the invention provides a light-emitting substrate, a display device and a manufacturing method, wherein the light-emitting substrate can avoid the problem that wires of a binding area are oxidized due to light-emitting units of the binding light-emitting area, so that the binding quality of a subsequent circuit board is ensured, and the product yield is improved.

In order to achieve the purpose, the embodiment of the invention adopts the following technical scheme:

In a first aspect, a light-emitting substrate is provided, comprising a binding region and a light-emitting region,

The binding region comprises a plurality of first bonding pads, any one of the plurality of first bonding pads comprises a first metal sub-layer and a first conductive sub-layer which are arranged in a stacked manner, the material of the first metal sub-layer comprises metal or metal alloy, and the first conductive sub-layer has oxidation resistance and covers the first metal sub-layer;

the light-emitting area comprises a plurality of second bonding pads which are used for binding connection with a plurality of light-emitting units;

The light-emitting substrate further comprises a substrate, the first conductive sub-layer is located at one side far away from the substrate relative to the first metal sub-layer, and the material of the first conductive sub-layer comprises copper-nickel alloy, and the proportion range of the copper-nickel alloy is 70:30-95:5.

Optionally, the material of the first metal sub-layer comprises copper or an alloy containing molybdenum.

Optionally, any one of the plurality of second bonding pads comprises a second metal sub-layer and a second conductive sub-layer which are stacked, wherein the second conductive sub-layer is positioned on one side far away from the substrate relative to the second metal sub-layer, the second metal sub-layer is arranged in the same layer as the first metal sub-layer, and the second conductive sub-layer is arranged in the same layer as the first conductive sub-layer.

Optionally, the materials of the first metal sub-layer and the second metal sub-layer include copper;

The first bonding pad further comprises a first buffer sub-layer, and the first metal sub-layer is positioned above the first buffer sub-layer;

The second bonding pad further comprises a second buffer sub-layer, and the second metal sub-layer is positioned above the second buffer sub-layer;

wherein the first buffer sub-layer and the second buffer sub-layer are arranged on the same layer.

Optionally, the material of the first buffer sub-layer and the second buffer sub-layer is an alloy containing molybdenum.

Optionally, the binding area further includes a first connection portion, and a first protection layer and a first flat layer that are stacked, where the first connection portion is located on a side of the first conductive sub-layer away from the substrate, and the first flat layer is located on a side of the first protection layer away from the substrate and covers an area between the plurality of first pads;

The light-emitting region further comprises a second connecting part, a second protection layer and a second flat layer, wherein the second protection layer and the second flat layer are stacked, the second connecting part is positioned on one side, far away from the substrate, of the second conductive sub-layer, the second protection layer covers the area between the plurality of second bonding pads, and the second flat layer is positioned on one side, far away from the substrate, of the second protection layer;

The first protection layer and the second protection layer are arranged on the same layer, and the first flat layer and the second flat layer are arranged on the same layer.

Optionally, the plurality of second bonding pads are divided into a plurality of groups of second bonding pads, and each group of second bonding pads comprises a cathode bonding pad and an anode bonding pad which are arranged in pairs;

The light-emitting substrate further comprises a first wire, a second wire and a third flat layer, wherein the second wire and the second bonding pads are arranged on the same layer, the first wire is close to the substrate relative to the second wire, and the third flat layer is close to the substrate relative to the second wire and covers the first wire;

the first wire is electrically connected with at least one of the plurality of first bonding pads and is used for transmitting an electric signal provided by the circuit board;

The second wires are used for realizing series connection or parallel connection of a plurality of groups of second bonding pads, and are also used for being electrically connected with the first wires through a via hole penetrating through the third flat layer.

In a second aspect, a display device is provided, including the above light-emitting substrate, a circuit board, and a plurality of light-emitting units;

The circuit board is electrically connected with the first bonding pads of the light-emitting substrate, and the light-emitting units are electrically connected with the second bonding pads of the light-emitting substrate.

Optionally, the display device further includes an encapsulation layer covering the light emitting unit, and a material of the encapsulation layer is silica gel.

In a third aspect, a method for manufacturing a display device is provided, including:

Forming the light-emitting substrate;

binding a plurality of light emitting units and a plurality of second bonding pads of the light emitting substrate;

And binding the circuit board and the plurality of first bonding pads of the light-emitting substrate.

The embodiment of the invention provides a light-emitting substrate, a display device and a manufacturing method, wherein the light-emitting substrate comprises a binding area and a light-emitting area, the binding area comprises a plurality of first bonding pads, the plurality of first bonding pads are used for being in binding connection with a circuit board, any one of the plurality of first bonding pads comprises a first metal sub-layer and a first conductive sub-layer which are arranged in a stacked mode, the first metal sub-layer comprises metal or metal alloy, the first conductive sub-layer has oxidation resistance and covers the first metal sub-layer, the light-emitting area comprises a plurality of second bonding pads, the plurality of second bonding pads are used for being in binding connection with a plurality of light-emitting units, the light-emitting substrate further comprises a substrate, the first conductive sub-layer is located on one side far away from the substrate relative to the first metal sub-layer, the material of the first conductive sub-layer comprises copper-nickel alloy, and the copper-nickel alloy ratio range of the copper-nickel alloy is between 70:30 and 95:5. In the light-emitting substrate, the first bonding pad of the binding region comprises the first metal sub-layer and the first conductive sub-layer, the material of the first conductive sub-layer comprises copper-nickel alloy, and the copper-nickel alloy has oxidation resistance and covers the first metal sub-layer.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the related art, the drawings that are required to be used in the embodiments or the related technical descriptions will be briefly described, and it is apparent that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to the drawings without inventive effort for those skilled in the art.

Fig. 1 is a schematic diagram of a partial structure of a light-emitting substrate according to an embodiment of the present invention;

FIG. 2 is a schematic cross-sectional view taken along the direction AA' of FIG. 1;

FIG. 3 is a schematic view of the structure after forming the LED and the encapsulation layer on the basis of FIG. 2;

Fig. 4 to 7 are schematic views of a manufacturing flow structure of another display device according to an embodiment of the present invention;

Fig. 8-9 are schematic views of a manufacturing process structure of another display device according to an embodiment of the present invention;

fig. 10-13 are schematic views of a manufacturing process structure of a display device according to another embodiment of the present invention;

fig. 14-20 are schematic views illustrating a manufacturing process and a structure of a display device according to another embodiment of the invention.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In the embodiments of the present invention, the words "first," "second," and the like are used to distinguish between the same item or similar items that have substantially the same function and function, and are merely used to clearly describe the technical solutions of the embodiments of the present invention, and are not to be construed as indicating or implying relative importance or implying that the number of technical features indicated is indicated.

In the embodiments of the present invention, the meaning of "plurality" is two or more, unless specifically defined otherwise.

In the embodiments of the present invention, the orientation or positional relationship indicated by the term "upper" or the like is based on the orientation or positional relationship shown in the drawings, only for convenience of description and simplification of description, and is not indicative or implying that the apparatus or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore, should not be construed as limiting the present invention.

Mini-LEDs (sub-millimeter light emitting diodes) refer to light emitting diodes with dimensions of 80-300 um. When the Mini-LEDs are used as pixel points of the display panel to form a self-luminous display, higher pixel density can be realized compared with a small-space LED display. When the Mini-LED is used as a light source in the backlight module, the ultrathin light source module can be manufactured through denser light source arrangement, and the display screen comprising the Mini-LED backlight module has better contrast ratio and high dynamic illumination rendering display effect by matching with the regional dimming technology. The micro LED micro light emitting diode with the size smaller than 80um can be directly used as the pixel point of the display panel such as near-eye, wearing, hand-held terminal and the like.

The light-emitting substrate according to the present application may be used as a substrate for providing a light source, or may be used for display, and the contrast is not limited.

In the related art, in order to complete binding of the Mini/Micro LEDs and the light-emitting substrate, solder paste needs to be arranged on a bonding pad to be electrically connected with the Mini/Micro LEDs on the light-emitting substrate, then the Mini/Micro LEDs are transferred to corresponding positions on the light-emitting substrate, and then fixation of the Mini/Micro LEDs and the light-emitting substrate is completed in a reflow soldering mode within a temperature range of 230-260 ℃. Then, the circuit board is bonded to the pads of the light emitting substrate to be electrically connected to the circuit board using a thermo-compression manner in a temperature range of 130-150 ℃.

The inventor finds that because different process conditions are needed for binding the Mini/Micro LED and the circuit board to the light-emitting substrate, the binding of the Mini/Micro LED and the circuit board cannot be realized synchronously, when one of the LED and the circuit board is bound, metal at a bonding pad on the light-emitting substrate corresponding to the other one is easy to oxidize, so that good electrical connection cannot be ensured later, and the product yield is reduced.

Embodiments of the present invention provide a light emitting substrate that may be configured to display or provide backlight, including a bonding region and a light emitting region.

As shown in fig. 2 and 6, the bonding area OA includes a plurality of first pads 1 for bonding connection with the circuit board, any one of the plurality of first pads includes a first metal sub-layer 11 and a first conductive sub-layer 12 which are stacked, the material of the first metal sub-layer includes a metal or a metal alloy, and the first conductive sub-layer has oxidation resistance and covers the first metal sub-layer.

The light emitting region OB includes a plurality of second pads for binding connection with the plurality of light emitting cells.

The material of the first metal sub-layer comprises a metal, such as copper, aluminum, molybdenum, titanium, etc. In view of low resistivity and high conductivity of copper, it is preferable that copper forms the first metal sub-layer, and in this case, the material of the first conductive sub-layer may be a metal oxide or a metal alloy, for example, the metal oxide may be Indium Zinc Oxide (IZO) or Indium Tin Oxide (ITO). If the material of the first metal sub-layer comprises a metal alloy, for example a molybdenum-containing alloy, the material of the first conductive sub-layer may be a metal alloy, for example a copper-containing alloy, for example a copper-nickel-containing alloy. The first conductive sub-layer has oxidation resistance and conductivity, so that the problem of oxidation occurring in the process of manufacturing the light emitting substrate can be avoided. Therefore, the first conductive sub-layer can play a role in protecting the first metal sub-layer, and oxidation of the first metal sub-layer in the process of manufacturing the light-emitting substrate is avoided.

The specific structure of the second bonding pad is not limited and may be determined according to practical requirements.

In the embodiments provided by the present disclosure, the light emitting substrate may be a display light emitting substrate or may be a backlight light emitting substrate. In the case of a display light-emitting substrate, the light-emitting region OB constitutes a display region to realize a display screen. In the case of a backlight light-emitting substrate, the light-emitting region OB is used to provide a light source.

The light emitting color of the light emitting region included in the light emitting substrate is not limited herein, and the light emitting region may be any one of a red light emitting region, a green light emitting region, or a blue light emitting region. The light-emitting substrate may include light-emitting regions of three light-emitting colors of a red light-emitting region, a green light-emitting region, or a blue light-emitting region at the same time, and of course, may include only light-emitting regions of one light-emitting color, for example, include only a plurality of red light-emitting regions, or include only a plurality of green light-emitting regions, or include only a plurality of blue light-emitting regions. And can be specifically determined according to actual requirements.

The control manner of the plurality of light emitting regions is not limited, and each light emitting region may be independently controlled, or the plurality of light emitting regions may be simultaneously controlled, or the like, for example.

In the embodiments provided in the present disclosure, as shown in fig. 3 and 7, the light emitting substrate may further include a substrate 7, and a plurality of light emitting units formed on the substrate 7, and the light emitting units may include the light emitting diode 6 as shown in fig. 7 or 3. The material of the substrate may be a rigid material, such as glass, or a flexible material, such as polyimide.

It should be noted that, since the light emitting diode includes an anode and a cathode, one light emitting diode needs to be bound through two second bonding pads. The plurality of second bonding pads may be divided into a plurality of groups of second bonding pads, each group of second bonding pads being used for bonding one light emitting diode and including a cathode bonding pad and an anode bonding pad arranged in pairs, wherein the second bonding pad bonded with the cathode of the light emitting diode is called a cathode bonding pad, and the second bonding pad bonded with the anode of the light emitting diode is called an anode bonding pad. In the drawings of the embodiments of the present invention, in order to clearly distinguish the cathode pad from the anode pad, different labels are used for explanation, specifically, referring to fig. 1 and 2, the cathode pad is labeled 2', the anode pad is labeled 2, but the two layers include the same film structure.

The distribution structure and the connection manner of the plurality of first bonding pads and the plurality of second bonding pads in the light-emitting substrate are not limited. As an example, referring to fig. 1, the area OA is a bonding area, the area OB is a light emitting area, and the plurality of second pads may be divided into a plurality of groups of second pads, each group of second pads being used to bond one light emitting diode and including a cathode pad 2' and an anode pad 2 arranged in pairs. The second bonding pads of two adjacent groups are connected in series by a wire 81, the anode bonding pad of one group is connected with one wire 82 and is electrically connected with the anode wire 51 by a via 4, the anode wire 51 is electrically connected with one first bonding pad 1 by a via (not shown in fig. 1), the cathode bonding pad of the other group is connected with the other wire 82 and is electrically connected with the cathode bonding wire 52 by another via 4, and the cathode bonding wire 52 is electrically connected with the other first bonding pad 1 by a via (not shown in fig. 1). In fig. 1, the cathode pad 2', the anode pad 2, the first pad 1, the trace 81 and the trace 82 are arranged in the same layer, and the anode trace 51 and the cathode trace 52 are arranged in the same layer, and the same filling pattern is adopted.

Fig. 2 is a schematic cross-sectional view along the direction AA 'in fig. 1, fig. 6 is another schematic cross-sectional view along the direction AA' in fig. 1, and fig. 3 is a schematic structural view after forming the light emitting diode 6 and the encapsulation layer 9 on the basis of fig. 2. Fig. 7 is a schematic structural view after forming the light emitting diode 6 and the encapsulation layer 9 on the basis of fig. 6.

It will be appreciated that the driving manner of the light emitting substrate is not limited in the present application, and the light emitting substrate may drive the light emitting unit in a passive manner, or may provide a signal to the light emitting unit through a driving circuit including a thin film transistor, or may provide a signal to the light emitting unit through a microchip, as shown in fig. 1.

The embodiment of the invention provides a light-emitting substrate, wherein a first bonding pad of a binding area comprises a first metal sub-layer and a first conductive sub-layer, and the first conductive sub-layer has oxidation resistance and covers the first metal sub-layer; in the manufacturing process of the light-emitting substrate, when the light-emitting unit is bound and connected with the second bonding pad in the light-emitting area, the first conductive sub-layer of the binding area cannot be oxidized, so that the binding quality of a subsequent circuit board is ensured, and the product yield is improved.

Alternatively, referring to fig. 2 and 6, the light emitting substrate comprises a substrate 7, and a first conductive sub-layer 12 is located on a side remote from the substrate 7 with respect to a first metal sub-layer 11, the material of the first conductive sub-layer comprising a metal oxide or a metal alloy.

Optionally, the material of the first metal sub-layer comprises copper, and the material of the first conductive sub-layer comprises indium zinc oxide or indium tin oxide. In view of better conductivity and lower resistivity of indium zinc oxide, the first conductive sub-layer is generally made of indium zinc oxide to avoid oxidation of the first metal sub-layer made of copper during the process of manufacturing the light-emitting substrate.

Further alternatively, referring to fig. 6, any one of the plurality of second pads includes a second metal sub-layer 21, the second metal sub-layer 21 being disposed in the same layer as the first metal sub-layer 11.

The same layer arrangement refers to the one-time patterning process. The primary patterning process refers to forming a desired pattern through a primary film forming and photolithography process. The primary patterning process comprises film forming, exposing, developing, etching, stripping and other processes. The second metal sub-layer and the first metal sub-layer are arranged on the same layer, so that the frequency of the composition process can be reduced, the manufacturing process is simplified, and the production cost is greatly reduced.

In the case of manufacturing the display substrate shown in fig. 6, the display substrate shown in fig. 4 may be manufactured first. In fig. 4, the second bonding pad includes a second metal sub-layer 21 and a second conductive sub-layer 22, where the second metal sub-layer is disposed in the same layer as the first metal sub-layer, and the second conductive sub-layer is disposed in the same layer as the first conductive sub-layer. In an embodiment provided by the present disclosure, the material of the first metal sub-layer comprises copper, and the material of the first conductive sub-layer comprises indium zinc oxide or indium tin oxide. And the second metal sub-layer is arranged on the same layer as the first metal sub-layer, and the second conductive sub-layer is arranged on the same layer as the first conductive sub-layer, so that the material of the second metal sub-layer comprises copper, and the material of the second conductive sub-layer comprises indium zinc oxide or indium tin oxide. Then, if the bonding between the light emitting unit and the light emitting substrate is completed by using a reflow process, solder paste needs to be disposed between the light emitting unit and the second bonding pad of the light emitting substrate. Since the indium zinc oxide or the indium tin oxide cannot realize a good fixable contact interface with the solder paste, and the material of the second conductive sub-layer includes the indium zinc oxide or the indium tin oxide, the solder paste cannot be directly disposed on the second conductive sub-layer, and the second conductive sub-layer in the second bonding pad needs to be removed to expose the second metal sub-layer, so that the display substrate shown in fig. 6 is obtained. The material of the second metal sub-layer comprises copper, which can be bonded with solder paste, so that the light emitting unit is bonded to the second metal sub-layer by a reflow soldering and bonding process. The circuit board is generally bound with the first conductive sub-layer by heat-curing glue in a hot pressing mode, and the part of the first conductive sub-layer used for binding with the circuit board is not required to be removed.

In addition, the materials of the first metal sub-layer and the second metal sub-layer comprise copper, in order to increase the adhesive force of the copper and reduce the manufacturing difficulty, the first bonding pad can further comprise a first buffer sub-layer, the first metal sub-layer is positioned on the first buffer sub-layer, the second bonding pad can further comprise a second buffer sub-layer, the second metal sub-layer is positioned on the second buffer sub-layer, the first buffer sub-layer and the second buffer sub-layer are arranged in the same layer, and the materials can be molybdenum-containing alloy, such as molybdenum-titanium-nickel alloy.

In the light-emitting substrate, the first bonding pad of the binding region comprises the first metal sub-layer and the first conductive sub-layer, and the first conductive sub-layer has oxidation resistance and covers the first metal sub-layer, so that when the light-emitting unit and the second metal sub-layer are bound in the light-emitting region in the manufacturing process of the light-emitting substrate, the first metal sub-layer of the binding region is protected by the first conductive sub-layer and cannot be oxidized, the binding quality of a subsequent circuit board is guaranteed, and the product yield is improved.

2-9, The bonding area OA further includes a first connection portion (not shown) located on a side away from the substrate with respect to the first conductive sub-layer, and a first planarization layer 14 covering an area between the plurality of first pads and exposing surfaces of the first pads and the second pads.

The light emitting region OB further includes a second connection portion (10 in fig. 7) located on a side away from the substrate with respect to the second metal sub-layer, and a second planarization layer 24 covering an area between the plurality of second pads.

Wherein the first flat layer and the second flat layer are arranged on the same layer, and can form an integral structure.

The first and second planarization layers may protect the first and second trace layers, respectively, while simultaneously serving as planarization layers to facilitate subsequent processing, and may be an organic material such as Resin (Resin).

The material of the first connecting part can be thermosetting glue, and the material of the second connecting part can be solder paste, copper paste and the like.

In the related art, as shown in fig. 20, a silicon oxynitride (SiON) insulating layer 104 is further provided between the second resin layer 105 and the thin copper layer 103. However, in the light-emitting substrate provided by the embodiment of the invention, the second conductive sub-layer is arranged above the first metal sub-layer, so that the second metal sub-layer is well protected, and the silicon oxynitride insulating layer in the original process is removed from the light-emitting substrate, so that the PECVD (PLASMA ENHANCED CHEMICAL Vapor Deposition) process and the silicon oxynitride etching process in the original process are omitted, the original process flow is simplified, and the manufacturing cost is reduced.

It should be noted that, referring to fig. 7, the light emitting substrate may further include an encapsulation layer 9 covering the light emitting unit 6 for protection and encapsulation, and the material of the encapsulation layer may be silica gel.

For ease of driving, the light emitting substrate may further include a first trace over the substrate, a second trace disposed in the same layer as the second pad. Referring to fig. 1, the first trace includes an anode trace 51 and a cathode trace 52, and the second trace includes a trace 81 and a trace 82. Referring to fig. 6, the trace 82 includes a third metal sub-layer 83 and a third conductive sub-layer 84, and the third metal sub-layer 83 is connected to the second metal sub-layer 21, which is separated by a dotted line in fig. 6.

Referring to fig. 6, the anode trace 51 may include only one layer structure, or may further include a first molybdenum-titanium-nickel alloy sub-layer, a copper sub-layer, and a second molybdenum-titanium-nickel alloy sub-layer, which are sequentially stacked. To reduce the voltage Drop (IR Drop), the copper sub-layer uses thick copper (compared to the copper thickness of the first conductive sub-layer), which is related to the product size of the Mini-LED back-plate, the larger the size, the larger the copper thickness required. The first molybdenum titanium nickel alloy sub-layer, the copper sub-layer and the second molybdenum titanium nickel alloy sub-layer can be manufactured in sequence by adopting a sputtering process, and the second molybdenum titanium nickel alloy sub-layer can protect the copper sub-layer and prevent the surface of the copper sub-layer from being oxidized.

Further, in order to protect and insulate the first trace, referring to fig. 6, the light emitting substrate may further include a third planarization layer 33 covering the first trace, and the first and second pads 1 and 2 are located on the third planarization layer 33, and a material of the third planarization layer may be an organic material, for example, a resin. Referring to fig. 6, the first metal sub-layer 11 and the third metal sub-layer 83 are electrically connected to the anode trace 51 through vias (not shown in fig. 6) penetrating the third planarization layer 33, respectively.

In embodiments provided by the present disclosure, the material of the first metal sub-layer comprises copper or an alloy comprising molybdenum, and the material of the first conductive sub-layer comprises an alloy comprising copper and nickel.

If the material of the first metal sub-layer includes copper, in order to increase the adhesion of copper and reduce the manufacturing difficulty, the first bonding pad may further include a first buffer sub-layer, where the first metal sub-layer is located above the first buffer sub-layer. At this time, the first pad includes a three-layer structure of a first buffer sub-layer, a first metal sub-layer (copper layer), and a first conductive sub-layer (alloy layer containing copper and nickel). Wherein the material of the first buffer sub-layer may be an alloy containing molybdenum, and the thickness thereof may beThe thickness of the first metal sub-layer may be in the range ofThe thickness of the first conductive sub-layer may be in the range of

If the material of the first metal sub-layer includes an alloy containing molybdenum, the first bonding pad 1 includes a two-layer structure of a first metal sub-layer (alloy layer containing molybdenum) 11 and a first conductive sub-layer (alloy layer containing copper and nickel) 12, as shown in fig. 2. Wherein the thickness of the first metal sub-layer may beThe thickness of the first conductive sub-layer may be in the range of

The first bonding pad is in a two-layer structure or a three-layer structure, and needs to be determined according to resistance requirements.

The material of the first conductive sub-layer comprises copper-nickel alloy, and the target material proportion of the copper-nickel alloy can be selected according to the resistance requirement and etching condition. Theoretically, the higher the nickel content, the more oxidation-resistant it is. However, nickel has magnetism, and the content of nickel is too high, so that on one hand, the difficulty in manufacturing a target material is increased, and on the other hand, the difficulty in subsequent patterning is increased, and therefore, the proportion of nickel cannot be too high. The applicant finds that the proportioning range can be selected from Cu: ni=70:30-95:5 through a large number of researches, and the copper-nickel alloy surface can be ensured not to be oxidized at the temperature of 300 ℃ in the proportioning range. The current copper-nickel alloy with Cu and Ni=80:20 can resist high temperature for half an hour under the environment of 230 ℃ and is not oxidized. The first table shows the difference of resistances under different proportions.

Optionally, referring to fig. 2, any one of the plurality of second pads includes a second metal sub-layer 21 and a second conductive sub-layer 22 that are stacked, the second conductive sub-layer 22 being located on a side away from the substrate 7 with respect to the second metal sub-layer 21, wherein the second metal sub-layer is disposed in a same layer as the first metal sub-layer, and the second conductive sub-layer is disposed in a same layer as the first conductive sub-layer.

List one

Material	Film thickness/A	Square resistance (omega/≡)
			Cu	880	0.35
CuNi(70:30)	800	5.3
			CuNi(90:10)	3800	0.4
CuNi(95:5)	3300	0.38

The same layer arrangement refers to the one-time patterning process. The primary patterning process refers to forming a desired pattern through a primary film forming and photolithography process. The primary patterning process comprises film forming, exposing, developing, etching, stripping and other processes. The second metal sub-layer and the first metal sub-layer are arranged in the same layer, and the second conductive sub-layer and the first conductive sub-layer are arranged in the same layer, so that the frequency of the composition process can be reduced, the manufacturing process is simplified, and the production cost is greatly reduced.

The second metal sub-layer is arranged on the same layer as the first metal sub-layer. If the material of the first metal sub-layer includes copper, at this time, the material of the second metal sub-layer also includes copper, in order to increase adhesion of copper and reduce manufacturing difficulty, the second bonding pad may further include a second buffer sub-layer, where the second metal sub-layer is located above the second buffer sub-layer. The second buffer sub-layer is arranged on the same layer as the first buffer sub-layer. At this time, the second pad includes a three-layer structure of a second buffer sub-layer, a second metal sub-layer (copper layer), and a second conductive sub-layer (alloy layer containing copper and nickel). If the material of the first metal sub-layer comprises an alloy containing molybdenum, the material of the second metal sub-layer also comprises an alloy containing molybdenum, and the second bonding pad comprises a two-layer structure of the second metal sub-layer (the alloy layer containing molybdenum) and the second conductive sub-layer (the alloy layer containing copper and nickel). The thickness ranges of the sub-layers may refer to the thickness ranges of the sub-layers included in the first pad, and are not described herein.

The second conductive sub-layer and the first conductive sub-layer are disposed in the same manner, and if the material of the first conductive sub-layer includes an alloy containing copper and nickel, at this time, the material of the second conductive sub-layer also includes an alloy containing copper and nickel, and the ratio range of copper and nickel in the alloy containing copper and nickel can be referred to the related description of the first conductive sub-layer, which is not repeated here.

In the light-emitting substrate, the first bonding pad of the binding region comprises a first metal sub-layer and a first conductive sub-layer, the first conductive sub-layer has oxidation resistance and covers the first metal sub-layer, so that when the light-emitting unit and the second conductive sub-layer are bound in the light-emitting region in the manufacturing process of the light-emitting substrate, the first conductive sub-layer protects the first metal sub-layer if the material of the first metal sub-layer comprises copper, so that oxidation of the first metal sub-layer is avoided, and the first conductive sub-layer comprises alloy containing molybdenum if the material of the first metal sub-layer comprises alloy containing copper and nickel, and has oxidation resistance and cannot oxidize. In sum, when the light-emitting unit and the second conductive sub-layer are bound in the light-emitting area, the first wiring layer in the binding area is prevented from being oxidized, so that the binding quality of a subsequent circuit board is ensured, and the product yield is improved.

Further alternatively, referring to fig. 2, the bonding area OA further includes a first connection portion (not shown in fig. 4) located at a side of the first conductive sub-layer away from the substrate, and a first protection layer 13 and a first planarization layer 14 stacked and disposed, the first planarization layer being located at a side of the first protection layer away from the substrate and covering an area between the plurality of first pads.

Referring to fig. 2, the light emitting region OB further includes a second connection portion (denoted as 10 in fig. 3) at a side of the second conductive sub-layer away from the substrate, a second protection layer 23 covering an area between the plurality of second pads, and a second planarization layer 24 at a side of the second protection layer away from the substrate.

The first flat layer and the second flat layer are arranged on the same layer, and can form an integrated structure.

The first and second protective layers are arranged on the same layer, and the material of the first and second protective layers can be silicon oxynitride, silicon nitride and the like, and the material of the first and second flat layers can be organic material, such as resin, for planarization, so as to facilitate the subsequent process.

The light emitting substrate may further include a first trace over the substrate, a second trace disposed on the same layer as the second pad. Referring to fig. 1, the first trace includes an anode trace 51 and a cathode trace 52, and the second trace includes a trace 81 and a trace 82. Referring to fig. 2, the trace 82 includes a third metal sub-layer 83 and a third conductive sub-layer 84, and the third metal sub-layer 83 is connected to the second metal sub-layer 21, which is separated by a dotted line in fig. 6.

Referring to fig. 2, the anode trace 51 may include only one layer structure in the first trace, or may further include a first molybdenum alloy sub-layer and a copper sub-layer sequentially stacked. Further, in order to avoid oxidation of the copper sub-layer, referring to fig. 2, the light emitting substrate may further include a third protection layer 34 covering the trace 51, and a material of the third protection layer may be silicon oxynitride, silicon nitride, or the like. Further, for planarization to facilitate the subsequent process, referring to fig. 2, the light emitting substrate may further include a third planarization layer 33 disposed on the third protection layer 34, the first and second pads are disposed on the third planarization layer 33, and the first and third metal sub-layers 11 and 83 are electrically connected to the anode traces 51 through vias penetrating the third planarization layer and the third protection layer, respectively. The material of the third planarization layer may be an organic material such as a resin. It should be noted that the anode trace may further include a second molybdenum alloy sub-layer disposed on the copper sub-layer, where the copper sub-layer is protected by the second molybdenum alloy sub-layer, and then a third protection layer is not required to be formed later. Fig. 2 illustrates an example in which the light emitting substrate includes a third passivation layer and a third planarization layer. In addition, in order to reduce the adhesion force of the third wiring layer and reduce the stress, the light emitting substrate may further include a buffer layer between the substrate and the first wiring, and the material of the buffer layer may be polyimide or the like.

In the embodiment provided by the present disclosure, referring to fig. 13, the light emitting substrate further includes a substrate 7, a plurality of first pads 1 are exposed at a surface facing the substrate 7 for binding the circuit board 5, and a plurality of second pads (anode pads 2 and cathode pads 2') are exposed at a surface remote from the substrate 7 for binding the light emitting unit 6.

As shown with reference to fig. 13, the light emitting substrate may further include a peeling layer 44, the peeling layer 44 being located between the substrate 7 and the first pad 1. At least a region (a mark 50 in fig. 12) corresponding to a portion of the first pad 1 for binding the circuit board 5 in the substrate 7 and the peeling layer 44 is removed. The material of the release layer may be a mechanically releasable material. The material of the substrate may be a rigid substrate, such as glass, or a flexible substrate, such as polyimide.

It should be noted that, in fig. 10 to 13, the structures of the first pad and the second pad are only schematically shown, and the multilayer structure included in the first pad is not shown.

In the light-emitting substrate, the first bonding pad comprises the first metal sub-layer and the first conductive sub-layer, so that when the light-emitting unit and the second metal sub-layer are bound, the first bonding pad of the binding area cannot be oxidized, the binding quality of the subsequent circuit board and the first conductive sub-layer is ensured, and the product yield is improved. In addition, in the light-emitting substrate, the circuit board is bound to one side, close to the stripping layer, of the first metal sub-layer, so that the non-light-emitting area of the light-emitting side is reduced, and a narrower frame can be realized.

Further, referring to fig. 13, the light emitting substrate further includes a first organic layer 41, and a protective layer 43 and a second organic layer 42 which are stacked, wherein the first organic layer 41 covers the first pads 1, and the second organic layer is located at a side of the protective layer away from the substrate and covers a region between the plurality of second pads. Referring to fig. 13, the light emitting substrate may further include an anode wire 82 disposed in the same layer as the second pad, the anode wire 82 being electrically connected to the first pad 1 through a via hole (not shown in fig. 13) penetrating the first organic layer 41. The anode trace 82 is connected to the anode pad 2, and is separated by a dotted line in fig. 13. In the light emitting substrate, the anode pad 2 and the cathode pad 2' are electrically connected to the anode and the cathode of the light emitting diode 6 through the second connection portion 10, respectively, and the circuit board 5 is electrically connected to the first pad 1 through the first connection portion (not shown in fig. 13). In the light emitting substrate, the first pad is located under the first organic layer 41, and the second pad is located over the first organic layer 41.

In the first bonding pad, the material of the first metal sub-layer may be copper or an alloy containing molybdenum, and the material of the first conductive sub-layer may be a metal oxide (for example, indium zinc oxide, indium tin oxide) or a metal alloy (for example, an alloy containing copper and nickel). If the material of the first metal sub-layer includes copper, the first bonding pad may further include an alloy sub-layer including molybdenum disposed under the first metal sub-layer, so as to facilitate fabrication of the first metal sub-layer. In the case where the light emitting substrate further includes a first organic layer, a protective layer, and a second organic layer, since the circuit board is bonded to a side of the first metal sub-layer, which is close to the release layer, it is not necessary to provide a via hole in a region of the first organic layer, the protective layer, and the second organic layer corresponding to the first metal sub-layer to expose the first bonding pad, and when the light emitting unit and the second metal sub-layer are bonded, the first bonding pad may be protected from oxidation by the first organic layer, the protective layer, and the second organic layer, and at this time, the first bonding pad may include only the first metal sub-layer (e.g., copper sub-layer, etc.) or the first conductive sub-layer (e.g., copper-nickel sub-layer, etc.). The material of the first organic layer may be polyimide and the material of the second organic layer may be resin.

The second pad may comprise only one metal sub-layer, which may be a copper sub-layer or a copper-containing alloy sub-layer (e.g. a copper-nickel-containing alloy sub-layer), although it may comprise multiple sub-layers. The former is selected in consideration of fully utilizing the original process as much as possible and reducing the manufacturing cost.

It should be noted that, referring to fig. 13, the light emitting substrate may further include an encapsulation layer 9 covering the light emitting unit for protection and encapsulation, and the material of the encapsulation layer may be silica gel.

Alternatively, referring to fig. 1, the plurality of second pads are divided into a plurality of groups of second pads, each group of second pads including a cathode pad 2' and an anode pad 2 arranged in pairs.

The light-emitting substrate further comprises a substrate, a first wire, a second wire and a third flat layer, wherein the second wire and the plurality of second bonding pads are arranged on the same layer, the first wire is close to the substrate relative to the second wire, and the third flat layer is close to the substrate relative to the second wire and covers the first wire.

The first wire is electrically connected with at least one of the plurality of first bonding pads and is used for transmitting electric signals provided by the circuit board.

The specific connection manner of the plurality of groups of second bonding pads is not limited. In fig. 1, two adjacent second pads are shown in series. Referring to fig. 1, a region OA is a bonding region, a region OB is a light emitting region, and a plurality of second pads may be divided into a plurality of groups of second pads, each group of second pads being used to bond one light emitting diode and including a cathode pad 2' and an anode pad 2 arranged in pairs. The first trace may include an anode trace 51 and a cathode trace 52, and the second trace includes a trace 81 and a trace 82. The second bonding pads of two adjacent groups are connected in series by a wire 81, wherein the anode bonding pad of one group is connected with one wire 82, the wire 82 is electrically connected with the anode bonding wire 51 through a via 4 penetrating the third flat layer, the anode bonding wire 51 is electrically connected with one first bonding pad 1 through a via (not shown in fig. 1) penetrating the third flat layer, the cathode bonding pad of the other group is connected with the other wire 82, the wire 82 is electrically connected with the cathode bonding wire 52 through another via 4 penetrating the third flat layer, and the cathode bonding wire 52 is electrically connected with the other first bonding pad 1 through a via (not shown in fig. 1) penetrating the third flat layer. In fig. 1, the cathode pad 2', the anode pad 2, the first pad 1, the trace 81 and the trace 82 are arranged in the same layer, and the anode trace 51 and the cathode trace 52 are arranged in the same layer, and the same filling pattern is adopted.

Of course, the light emitting substrate may further include a third protection layer, where the third protection layer is located between the third flat layer and the first wire and covers the first wire, and at this time, the second wire needs to be electrically connected to the first wire through a via hole penetrating through the third flat layer and the third protection layer.

The embodiment of the invention also provides a backlight module, which comprises the light-emitting substrate disclosed in the embodiment.

According to the related art, the backlight module may further include a diffusion plate, a driving circuit, and other structures, which may be specifically determined according to actual needs, and will not be described herein.

The backlight module can be used in any display device or component that needs to provide backlight, and the backlight module can be a rigid backlight module or a flexible backlight module (i.e. bendable and foldable), and is not limited herein.

Compared with the traditional backlight module, when the Mini-LED is used as a light source to be applied to the backlight module, the ultrathin light source module can be manufactured through denser light source arrangement, and the display screen comprising the Mini-LED backlight module has better contrast ratio and high dynamic illumination rendering display effect by matching with the regional dimming technology. The LCD adopting Mini-LED backlight is far superior to the existing LCD in terms of brightness, contrast, color rendition and power consumption, even can compete with the active matrix organic light emitting diode display screen in terms of contrast, power consumption and the like, and meanwhile, the production cost can be controlled by utilizing the existing LCD production line.

The structure of the light emitting substrate in this embodiment may refer to the related description of the light emitting substrate in the above embodiment, and will not be repeated here.

The embodiment of the invention also provides a display device which comprises the light-emitting substrate, the circuit board and the plurality of light-emitting units, wherein the light-emitting substrate, the circuit board and the plurality of light-emitting units are disclosed in the embodiment, the circuit board is electrically connected with the plurality of first bonding pads of the light-emitting substrate, and the plurality of light-emitting units are electrically connected with the plurality of second bonding pads of the light-emitting substrate.

The display device has the characteristics of high contrast, good brightness, high color rendition and the like. The display device may be a rigid display device or a flexible display device (i.e., bendable and foldable). The display device can be any product or component with display function such as a television, a digital camera, a mobile phone, a tablet computer and the like.

The embodiment of the invention also provides a manufacturing method of the display device, which comprises the following steps:

S1, forming the light-emitting substrate disclosed in the embodiment.

S2, binding a plurality of light emitting units and a plurality of second bonding pads of the light emitting substrate.

Specifically, if the light emitting unit includes a light emitting diode, the plurality of second pads are divided into a plurality of groups of second pads, and each group of second pads includes a cathode pad and an anode pad that are arranged in pairs, the anode and the cathode of the light emitting diode are respectively and correspondingly electrically connected with the anode pad and the cathode pad. In this step, the bonding may be accomplished using a reflow process.

S3, binding a plurality of first bonding pads of the circuit board and the luminous substrate.

In this step, the binding may be accomplished by hot pressing.

The embodiment of the invention provides a manufacturing method of a display device, wherein in a light-emitting substrate formed in step S1, a first bonding pad of a bonding area comprises a first metal sub-layer and a first conductive sub-layer, and the first conductive sub-layer has oxidation resistance and covers the first metal sub-layer, so that the first conductive sub-layer of the bonding area cannot be oxidized when step S2 is executed, the bonding quality of a circuit board in the subsequent step S3 is ensured, and the product yield is improved.

The embodiment of the invention further provides a manufacturing method of a display device, where the structure of the light-emitting substrate included in the display device may be shown in fig. 6 or fig. 9, and the method includes:

S11, sequentially forming a metal film and a conductive film and patterning to obtain a first metal sub-layer 11, a second metal sub-layer 21, a first conductive sub-layer 12 located above the first metal sub-layer 11, and a second conductive sub-layer 22 located above the second metal sub-layer 21 as shown in fig. 4.

Here, the metal sub-layer thin film and the conductive sub-layer thin film may be deposited in one step using a sputtering process, and may be patterned using one-step etching with a copper etching solution to form a first metal sub-layer, a first conductive sub-layer, a second metal sub-layer, and a second conductive sub-layer. A Mask (Mask) is required to form a desired pattern in S11.

The first pad and the second pad formed by S11 each include a two-layer structure. The first metal sub-layer and the second metal sub-layer are made of copper, the first bonding pad can further comprise a first buffer sub-layer, the first metal sub-layer is arranged on the first buffer sub-layer, the second bonding pad can further comprise a second buffer sub-layer, the second metal sub-layer is arranged on the second buffer sub-layer, the first buffer sub-layer and the second buffer sub-layer are arranged in the same layer, and the material can be an alloy containing molybdenum, such as molybdenum titanium nickel alloy. If the first bonding pad and the second bonding pad further comprise a first buffer sub-layer and a second buffer sub-layer respectively, the buffer sub-layer film, the metal sub-layer film and the conductive sub-layer film can be deposited in one step by adopting a sputtering process, and can be patterned by adopting copper etching liquid in one step to form the first buffer sub-layer, the second buffer sub-layer, the first metal sub-layer, the second metal sub-layer, the first conductive sub-layer and the second conductive sub-layer.

And S12, removing the part of the second conductive sub-layer used for binding with the light emitting unit (namely removing the second conductive sub-layer at the position of the second bonding pad) to obtain the light emitting substrate shown in fig. 6.

The material of the second conductive sub-layer includes indium zinc oxide or indium tin oxide, and is generally made of indium zinc oxide in view of better conductivity and lower resistivity of indium zinc oxide. The indium zinc oxide can be etched by any acidic species. As shown in fig. 5, a part of the second conductive sub-layer for binding with the light emitting unit may be etched by using a screen etching process, so that the light emitting unit is bound to the second metal sub-layer by using solder paste through a reflow soldering die bonding process. In fig. 5, tool 40 is used to push the indium zinc oxide etching paste 30 up from the mask plate 20 to the area to be etched.

S13, binding the light-emitting unit and the second metal sub-layer.

Specifically, a solder paste brushing process, a light emitting diode packaging process, a reflow soldering process, a silicone encapsulation process and the like are sequentially performed to complete binding of the light emitting unit and the second metal sub-layer, so that the light emitting substrate shown in fig. 7 is formed. Because the first conductive sub-layer plays a role in protecting the first metal sub-layer, oxidation of the first metal sub-layer in S13 can be avoided, binding quality of a subsequent circuit board is further guaranteed, and product yield is improved.

S14, binding the circuit board and the first conductive sub-layer.

Specifically, the circuit board and the first conductive sub-layer may be bound together by the first connection portion.

The manufacturing method of the light-emitting substrate is simple and easy to realize and has strong operability.

Optionally, before removing the portion of the second conductive sub-layer for binding with the light emitting unit in S12, and after sequentially forming and patterning the metal thin film and the conductive thin film in S11, the method further includes:

And S15, forming an organic film and patterning to obtain a first flat layer and a second flat layer 24 shown in FIG. 6, wherein the second flat layer is provided with a second via hole in a region corresponding to the second metal sub-layer so as to expose the second bonding pad.

The material of the first and second planarization layers may be an organic material, such as a resin. In S15, a mask is used to form the desired pattern.

At this time, S13, binding the light emitting unit and the second metal sub-layer includes:

S131, forming a second connection part in the second via hole, wherein the second connection part is electrically connected with the second metal sub-layer. The material of the second connection portion may be solder paste, copper paste, etc., and solder paste is usually used in practice.

S132, binding the light-emitting unit on the second connecting part.

Specifically, the bonding can be performed by adopting a reflow soldering die bonding process, wherein the peak temperature of the reflow soldering is about 240 ℃ and the holding time is 90s.

Naturally, after S132, in order to better protect the light emitting unit, the light emitting unit is further encapsulated with an encapsulating material such as silicone, so as to form an encapsulation layer 9 as shown in fig. 7. Typically the silica gel is cured at 150 ℃ for 4 hours.

Optionally, after S13, binding the light emitting unit and the second metal sub-layer, and before S14, binding the circuit board and the first conductive sub-layer, the method further includes:

Referring to fig. 8 and 9, s16, a region of the first planarization layer 14 corresponding to the first conductive sub-layer 12 is partially etched to form a first via hole to expose the first pad. It should be noted that the light emitting region has been packaged before S16 is performed. Because the packaging layer is thicker, the first via hole is etched in the S16, the influence on the light emitting area is smaller, and therefore a mask plate is not required to be additionally used.

S14, binding the circuit board and the first conductive sub-layer comprises the following steps:

S141, forming a first connection part in the first via hole, wherein the first connection part is electrically connected with the first conductive sub-layer.

S142, binding the circuit board on the first connecting part.

Here, the material of the first connection portion may be a thermosetting adhesive, and the circuit board may be bonded by a hot pressing method, where the temperature is generally 130 ℃ to 150 ℃.

It should be noted that, through S15 and S16 respectively form second via hole and first via hole, like this when S13, bind light emitting unit and second metal sublayer, be provided with first flat layer above the first pad, first flat layer can play the guard action to first pad, prevents that it from taking place oxidation. Therefore, when the method is adopted for manufacturing, the first bonding pad can also only comprise the first metal sub-layer without arranging the first conductive sub-layer, and correspondingly, the second bonding pad can also only comprise the second metal sub-layer without arranging the second conductive sub-layer.

In addition, since the first bonding pad includes the first metal sub-layer and the first conductive sub-layer, the first conductive sub-layer plays a good role in protecting the first metal sub-layer, so S16 may also be incorporated into S15, that is, in S15, the first via hole and the second via hole are formed at the same time to expose the first bonding pad and the second bonding pad, and the formed light-emitting substrate structure may be as shown in fig. 6. In this way, when the light emitting unit and the second metal sub-layer are bound in S13, even if the first bonding pad is exposed, oxidation of the first metal sub-layer and itself can be avoided due to the good oxidation resistance of the first conductive sub-layer.

In the manufacturing method, one mask is used in each of S11 and S15. In addition, if the light-emitting substrate shown in fig. 9 is to be formed, the manufacturing method further includes forming a first trace including an anode trace 51 and a cathode trace (not shown in fig. 9) before S11. Then, 4 masks (4 masks) are required in total to form the light emitting substrate shown in fig. 9.

In the related art, as shown in fig. 20, a manufacturing method of a 4-channel mask is generally adopted, and includes forming a thick copper layer 101 on a glass substrate 100, forming a first Resin layer (Resin-1) 102, as shown in fig. 15, forming a thin copper layer 103, as shown in fig. 15, forming a silicon oxynitride insulating layer 104, as shown in fig. 16, forming a second Resin layer (Resin-2) 105, as shown in fig. 16, on a glass substrate 100, forming a thick copper layer 101, as shown in fig. 14, forming a thin copper layer 103, as shown in fig. 15, forming a silicon oxynitride insulating layer 104, as shown in fig. 16, forming a second Resin layer (Resin-2) 105, as shown in fig. 17, and forming openings in a diode Bonding region (LED Bonding Pad) and a flexible circuit board Bonding region (FPC Bonding Pad), as shown in fig. 18, and performing dry etching on the opening regions to expose the thin copper layer, thereby forming a Mini-LED light emitting substrate, as shown in fig. 19. Then, a post-process is performed. The back-end process comprises brushing tin paste, transferring light-emitting diodes, reflow soldering and crystal fixing, screen printing silica gel and curing the silica gel. The completed light-emitting substrate is shown in fig. 20. Wherein the reflow peak temperature is about 240 ℃ and the holding time is 90s. The curing temperature of the silica gel is 150 ℃ and is kept for 4 hours. The copper surface of the binding area of the flexible circuit board is changed into dark red due to the temperature processes, and oxidation occurs, so that poor binding of the subsequent flexible circuit board is caused, and the product yield is reduced. In fig. 20, the anode 108 and the cathode 109 of the micro light emitting diode 107 are electrically connected to the thin copper layer 103 through solder paste 110, respectively, and the light emitting substrate further includes a silicone encapsulation layer 106.

Compared with the related art, the method for manufacturing the light-emitting substrate does not increase the number of mask plates, and meanwhile can avoid the problem that the first metal sub-layer manufactured by copper is oxidized in the process of manufacturing the light-emitting substrate, so that the binding quality of the circuit board is ensured, and the product yield is improved. In addition, in the light-emitting substrate provided by the embodiment of the invention, the second conductive sub-layer is arranged above the first metal sub-layer, so that the second metal sub-layer is well protected, and therefore, the process of the silicon oxynitride protective layer in the original process is eliminated in the manufacturing method of the light-emitting substrate, and the PECVD (PLASMA ENHANCED CHEMICAL Vapor Deposition) process and the silicon oxynitride etching process in the original process are omitted, so that the original process flow is simplified, and the manufacturing cost is reduced.

The embodiment of the invention also provides a manufacturing method of the display device, the structure of the light-emitting substrate included in the display device can be shown with reference to fig. 2, and the method includes:

and S21, sequentially forming a metal film and a conductive film and patterning to obtain a first metal sub-layer, a second metal sub-layer, a first conductive sub-layer positioned on the first metal sub-layer and a second conductive sub-layer positioned on the second metal sub-layer.

Here, the metal sub-layer thin film and the conductive sub-layer thin film may be deposited in one step using a sputtering process, and may be patterned using one-step etching with an etching solution to form a first metal sub-layer, a first conductive sub-layer, a second metal sub-layer, and a second conductive sub-layer. A mask is used in S21 to form a desired pattern.

It should be noted that, the first routing layer and the second routing layer formed by S21 respectively include two-layer structures. If the materials of the first metal sub-layer and the second metal sub-layer comprise copper, the first bonding pad can further comprise a first buffer sub-layer, the first metal sub-layer is positioned on the first buffer sub-layer, and the second bonding pad can further comprise a second buffer sub-layer, wherein the second metal sub-layer is positioned on the second buffer sub-layer, so that the adhesion of copper is increased, and the manufacturing difficulty is reduced. If the first bonding pad and the second bonding pad further include a first buffer sub-layer and a second buffer sub-layer, the buffer sub-layer film, the metal sub-layer film and the conductive sub-layer film may be deposited in one step by using a sputtering process, and may be patterned by using an etching solution for one-step etching, so as to form the first buffer sub-layer, the second buffer sub-layer, the first metal sub-layer, the second metal sub-layer, the first conductive sub-layer and the second conductive sub-layer.

If the material of the first metal sub-layer and the second metal sub-layer comprises an alloy containing molybdenum, the first bonding pad comprises a two-layer structure of the first metal sub-layer (the alloy layer containing molybdenum) and the first conductive sub-layer (the alloy layer containing copper and nickel), and the second bonding pad comprises a two-layer structure of the second metal sub-layer (the alloy layer containing molybdenum) and the second conductive sub-layer (the alloy layer containing copper and nickel).

S22, binding the light-emitting unit and the second conductive sub-layer.

Specifically, the processes of brushing solder paste, light-emitting diode (led) molding, reflow soldering, and silicone encapsulation can be sequentially performed to complete the binding of the light-emitting unit and the second metal sub-layer. In the step S22, if the material of the first metal sub-layer comprises copper, the first conductive sub-layer protects the first metal sub-layer from oxidation, and if the material of the first metal sub-layer comprises an alloy containing molybdenum, the material of the first conductive sub-layer comprises an alloy containing copper and nickel, and the first conductive sub-layer has oxidation resistance and does not oxidize. In sum, when the light-emitting unit and the second conductive sub-layer are bound in the light-emitting area, the first wiring layer in the binding area is prevented from being oxidized, so that the binding quality of a subsequent circuit board is ensured, and the product yield is improved.

S23, binding the circuit board and the first conductive sub-layer.

The manufacturing method of the luminous substrate is simple and easy to realize and has strong operability.

Optionally, before S22, binding the light emitting unit and the second conductive sub-layer, and after S21, sequentially forming and patterning the metal thin film and the conductive thin film, the method further includes:

And S24, sequentially forming a first film and a second film and patterning to obtain a first protective layer, a second protective layer, a first flat layer, a second flat layer and a second via hole, wherein the second via hole penetrates through the second protective layer and the second flat layer so as to expose the second bonding pad.

The material of the first film may be silicon oxynitride, silicon nitride, or the like for forming the first protective layer and the second protective layer, and the material of the second film may be resin for forming the first flat layer and the second flat layer. In S24, a mask is used to form a desired pattern.

S22, binding the light emitting unit and the second conductive sub-layer comprises:

S221, forming a second connection part in the second via hole, wherein the second connection part is electrically connected with the second conductive sub-layer. The second connection part can be solder paste, copper paste and the like, and solder paste is practically used.

S222, binding the light-emitting unit on the second connecting part.

Specifically, the bonding can be performed by adopting a reflow soldering and die bonding process, wherein the temperature of reflow soldering is 230-260 ℃ and the retention time is 90s.

Naturally, after S222, in order to better protect the light emitting unit, the light emitting unit is further encapsulated by an encapsulating material such as silica gel. Typically the silica gel is cured at 150 ℃ for 4 hours.

After S22, binding the light emitting unit and the second conductive sub-layer, and before S23, binding the circuit board and the first conductive sub-layer, the method further includes:

And S25, partially etching the first protection layer and the area corresponding to the first conductive sub-layer in the first flat layer to form a first via hole so as to expose the first bonding pad. It should be noted that the light emitting region has been packaged before S25 is performed. Because the packaging layer is thicker, the first via hole is etched in S25, and the influence on the light emitting area is smaller, so that a mask plate is not required to be additionally used.

S23, binding the circuit board and the first conductive sub-layer comprises:

s231, forming a first connection part in the first via hole, wherein the first connection part is electrically connected with the first conductive sub-layer.

S232, binding the circuit board on the first connecting part.

Here, the first connection portion may be a thermosetting adhesive, and may be bonded to the circuit board by a hot pressing method, where the temperature is generally 130 ℃ to 150 ℃.

It should be noted that, through the second via hole and the first via hole formed in S24 and S25 respectively, when the light emitting unit and the second metal sub-layer are bound in S22, the first protection layer and the first flat layer are disposed above the first bonding pad, and the first protection layer and the first flat layer can protect the first bonding pad to prevent oxidation. Therefore, when the method is adopted for manufacturing, the first bonding pad can also only comprise a copper sub-layer or a copper-containing alloy sub-layer, two layers of conductive structures do not need to be arranged, and correspondingly, the second bonding pad can also only comprise the copper sub-layer or the copper-containing alloy sub-layer.

In addition, since the first bonding pad includes the first metal sub-layer and the first conductive sub-layer, the first conductive sub-layer plays a good role in protecting the first metal sub-layer, so S25 may also be incorporated into S24, that is, in S24, the first via hole and the second via hole are formed at the same time, so as to expose the first bonding pad and the second bonding pad. In this way, when the light emitting unit and the second metal sub-layer are bound in S22, even if a part of the first bonding pad is exposed due to the first via hole, oxidation of the first metal sub-layer and itself can be avoided due to the good oxidation resistance of the first conductive sub-layer.

In the manufacturing method, one mask is used in each of S21 and S24. In addition, if the light-emitting substrate shown in fig. 2 is to be formed, the manufacturing method further includes forming a first trace, a third protection layer 34 and a third planarization layer 33, respectively, before S21, wherein the first trace includes an anode trace 51 and a cathode trace (not shown in fig. 2). One mask is required to form the third trace, and one mask is required to form the third protection layer 33 and the third planarization layer 34. Then, 4 masks (4 masks) are required in total to form the light emitting substrate shown in fig. 2.

Compared with the related art, the method for manufacturing the light-emitting substrate does not increase the number of mask plates, and meanwhile can avoid the problem that the first metal sub-layer manufactured by copper is oxidized in the process of manufacturing the light-emitting substrate, so that the binding quality of the circuit board is ensured, and the product yield is improved.

The embodiment of the present invention further provides a method for manufacturing a display device, where the structure of a light-emitting substrate included in the display device may be shown in fig. 13, and the method includes:

s31, forming a stripping layer on the substrate, wherein the stripping layer is positioned in the binding area and the light-emitting area.

The material of the release layer may be a mechanically releasable material. The material of the substrate may be a rigid material, such as glass, or may be a flexible material, such as Polyimide (PI).

And S32, forming a first bonding pad 1 and a second bonding pad (a cathode bonding pad 2' and an anode bonding pad 2) on the stripping layer, wherein the first bonding pad comprises a first metal sub-layer and a first conductive sub-layer which are stacked. The light emitting substrate formed may be as shown with reference to fig. 10.

Before the bonding process, referring to fig. 11, a partial laser lift-off (LLO) process and a light emitting substrate dicing are completed at a circuit bonding board position to obtain a single light emitting substrate to be bonded, and then a subsequent bonding process is performed on the single light emitting substrate to be bonded.

S33, binding the light emitting unit and the second bonding pad.

Specifically, the processes of brushing solder paste, light-emitting diode (led) packaging, reflow soldering, and silicone packaging can be sequentially performed to complete the binding of the light-emitting unit and the second wiring layer.

S34, removing at least the area (marked 50 in fig. 12) of the substrate and the peeling layer corresponding to the portion of the first metal sub-layer for binding the circuit board, and exposing a portion of the first metal sub-layer.

Specifically, partial dicing may be used to remove the substrate and the region of the release layer corresponding to the portion of the first metal sub-layer used for binding the circuit board.

S35, binding the circuit board and the first metal sub-layer.

In particular, the circuit board and the first metal sub-layer may be bound together by the first connection.

In the method, the formed first bonding pad comprises the first metal sub-layer and the first conductive sub-layer, so that the first bonding pad of the binding area cannot be oxidized when the light-emitting unit and the second metal sub-layer are bound, the binding quality of the subsequent circuit board and the first conductive sub-layer is ensured, and the product yield is improved. In addition, in the method, the circuit board is bound to one side, close to the stripping layer, of the first metal sub-layer, so that the non-light-emitting area of the light emitting side is reduced, and a narrower frame can be realized.

Further alternatively, referring to fig. 13, the light emitting substrate further includes a first organic layer 41, a protective layer 43, a second organic layer 42, a via (not labeled in fig. 13), and a second connection portion 10, the first organic layer covering the first pad. The second bonding pad is positioned above the first organic layer, and the protective layer covers the second bonding pad and the first organic layer, and the second organic layer is positioned above the protective layer. The via hole penetrates through the second organic layer and the protective layer to expose the second bonding pad, and the light emitting unit is electrically connected with the second bonding pad through the second connection part.

In addition, the step of forming a second bonding pad, the step of forming a first organic layer, and the step of forming a protective layer, the second organic layer and the via hole respectively require a mask. The total formation of the light-emitting substrate shown in fig. 13 requires 4 masks, and compared with the related art, the number of masks is not increased, and meanwhile, the problem that the first bonding pad is oxidized in the process of manufacturing the light-emitting substrate can be avoided, so that the binding quality of the circuit board is ensured, and the product yield is improved. In addition, in the method, the circuit board is bound to one side, close to the stripping layer, of the first metal sub-layer, so that the non-light-emitting area of the light emitting side is reduced, and a narrower frame can be realized.

The foregoing is merely illustrative of the present invention, and the present invention is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A light-emitting substrate, comprising a binding area and a light-emitting area, characterized in that:

The binding area includes a plurality of first pads, and the plurality of first pads are used for binding and connecting with the circuit board; any one of the plurality of first pads includes a first metal sublayer and a first conductive sublayer which are stacked; the material of the first metal sublayer includes a metal or a metal alloy; the first conductive sublayer has oxidation resistance and covers the first metal sublayer;

The light-emitting area includes a plurality of second pads, and the plurality of second pads are used for binding and connecting with a plurality of light-emitting units;

The light-emitting substrate also includes a substrate. The first conductive sublayer is located on a side away from the substrate relative to the first metal sublayer. The material of the first conductive sublayer includes an alloy containing copper and nickel. The ratio of the copper and nickel alloy ranges from 70:30 to 95:5.

2 . The light-emitting substrate according to claim 1 , wherein the material of the first metal sublayer comprises copper or an alloy containing molybdenum.

3. The light-emitting substrate according to claim 1 is characterized in that any one of the plurality of second pads comprises a second metal sublayer and a second conductive sublayer that are stacked, and the second conductive sublayer is located on a side away from the substrate relative to the second metal sublayer; wherein the second metal sublayer is arranged on the same layer as the first metal sublayer, and the second conductive sublayer is arranged on the same layer as the first conductive sublayer.

4. The light-emitting substrate according to claim 3, characterized in that the material of the first metal sublayer and the second metal sublayer comprises copper;

The first pad further includes a first buffer sublayer, and the first metal sublayer is located on the first buffer sublayer;

The second pad further includes a second buffer sublayer, and the second metal sublayer is located on the second buffer sublayer;

Wherein, the first buffer sublayer and the second buffer sublayer are arranged in the same layer.

5 . The light-emitting substrate according to claim 4 , wherein the material of the first buffer sublayer and the second buffer sublayer is an alloy containing molybdenum.

6. The light-emitting substrate according to claim 3, characterized in that the binding area further comprises a first connection portion, and a first protective layer and a first flat layer which are stacked, the first connection portion is located on a side of the first conductive sublayer away from the substrate, and the first flat layer is located on a side of the first protective layer away from the substrate and covers an area between the plurality of first pads;

The light-emitting area further includes a second connection portion, and a second protection layer and a second flat layer which are stacked, wherein the second connection portion is located on a side of the second conductive sublayer away from the substrate, the second protection layer covers an area between the plurality of second pads, and the second flat layer is located on a side of the second protection layer away from the substrate;

The first protection layer and the second protection layer are arranged on the same layer, and the first planarization layer and the second planarization layer are arranged on the same layer.

7. The light-emitting substrate according to any one of claims 1 to 6, characterized in that the plurality of second pads are divided into a plurality of groups of second pads, and each group of the second pads comprises a cathode pad and an anode pad arranged in pairs;

The light-emitting substrate further includes a first routing line, a second routing line arranged on the same layer as the plurality of second pads, and a third flat layer, wherein the first routing line is arranged close to the substrate relative to the second routing line, and the third flat layer is arranged close to the substrate relative to the second routing line and covers the first routing line;

The first trace is electrically connected to at least one of the plurality of first pads and is used to transmit an electrical signal provided by the circuit board;

The second routing line is used to realize series connection or parallel connection of multiple groups of the second pads, and is also used to be electrically connected to the first routing line through a via hole penetrating the third planar layer.

8. A display device, characterized by comprising the light-emitting substrate, the circuit board and a plurality of light-emitting units according to any one of claims 1 to 7;

The circuit board is electrically connected to a plurality of first pads of the light emitting substrate, and the plurality of light emitting units are electrically connected to a plurality of second pads of the light emitting substrate.

9 . The display device according to claim 8 , further comprising a packaging layer covering the light-emitting unit, wherein the packaging layer is made of silica gel.

10. A method for manufacturing a display device according to claim 8, characterized in that it comprises:

Forming a light-emitting substrate as described in any one of claims 1 to 7;

Binding a plurality of light-emitting units to a plurality of second pads of the light-emitting substrate;

A plurality of first solder pads are bonded to the circuit board and the light emitting substrate.