A display device and a method for manufacturing the same

Abstract

The present application provides a display device and a manufacturing method thereof. The display device includes: a substrate and circuit traces disposed on the substrate; wherein, the circuit traces include a first conductive layer, a second conductive layer, and a third conductive layer that are sequentially stacked on the substrate, the second conductive layer is fixedly connected to the first conductive layer and the third conductive layer respectively, and a plurality of grooves are formed on a side of the first conductive layer close to the second conductive layer, and at least a part of the second conductive layer is disposed in the grooves. By providing the grooves on the first conductive layer in the present application, the area of the bonding region between the first conductive layer and the second conductive layer can be increased, and the adhesion and fixing effect between the first conductive layer and the second conductive layer can be improved.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to a display device and a method for preparing the same. Background Art

[0002] Among the current display technologies, Micro-LED display has disadvantages such as many technical difficulties and complex technologies. In particular, mass transfer technology and LED particle miniaturization have become bottlenecks restricting its technological development. Compared with Micro-LED display, Mini-LED display has a more mature and easier to implement production and manufacturing process, and has advantages such as high contrast and high color rendering performance that are comparable to OLED display devices. At the same time, the cost is only about 60% of that of OLED display, making Mini-LED display technology a hot technology that major panel manufacturers are actively deploying.

[0003] However, in existing Mini-LED display devices, in order to meet the larger driving current requirements of the driver IC, it is necessary to set metal traces that meet certain thickness specifications on the driver backplane. However, the existing film forming process is difficult to directly form metal traces that meet the thickness requirements. Even if metal traces that meet the thickness requirements are finally formed, the metal traces often still have problems such as poor adhesion and stress warping. This problem needs to be solved urgently. Summary of the invention

[0004] The present application provides a display device and a method for manufacturing the same, which can effectively solve the problem of metal wiring that meets thickness requirements in existing display devices being easily warped due to stress and having poor adhesion.

[0005] To solve the above problems, on the one hand, the present application provides a display device, the display device comprising: a substrate and a wiring arranged on the substrate;

[0006] Among them, the routing includes a first conductive layer, a second conductive layer and a third conductive layer which are stacked in sequence on the substrate, the second conductive layer is fixedly connected to the first conductive layer and the third conductive layer respectively, and a plurality of grooves are arranged on the side of the first conductive layer close to the second conductive layer, and at least part of the second conductive layer is arranged in the grooves.

[0007] Optionally, a depth of any of the grooves is less than a maximum thickness of the first conductive layer.

[0008] Optionally, the display device includes a eutectic structure, wherein the eutectic structure is formed between the first conductive layer and the second conductive layer; and the eutectic structure is formed between the third conductive layer and the second conductive layer.

[0009] Optionally, the eutectic structure includes a first fixed connection layer formed between the first conductive layer and the second conductive layer, and a second fixed connection layer formed between the second conductive layer and the third conductive layer.

[0010] Optionally, the maximum thickness of the third conductive layer is less than the maximum thickness of the first conductive layer.

[0011] Optionally, the contact area between the first fixed connection layer and the second conductive layer is greater than the contact area between the second fixed connection layer and the second conductive layer, and the contact area between the first fixed connection layer and the first conductive layer is greater than the contact area between the second fixed connection layer and the third conductive layer.

[0012] Optionally, on the side of the second conductive layer close to the first conductive layer, there are a plurality of protrusions with the same number as the grooves, and each of the protrusions is correspondingly located in each of the grooves.

[0013] Optionally, the surface of the side of the second conductive layer close to the third conductive layer is a flat surface.

[0014] On the other hand, the present application provides a method for manufacturing a display device, and the method for manufacturing the display device includes the following steps:

[0015] Provide a substrate and form a first conductive layer, the first conductive layer is disposed on the substrate, and a plurality of grooves are provided on the side of the first conductive layer away from the substrate;

[0016] Form a photoresist layer, the photoresist layer is disposed on the first conductive layer and is formed with a plurality of hollow portions surrounding the grooves;

[0017] Form a second conductive layer, at least a part of the second conductive layer is located in the grooves;

[0018] Form a third conductive layer, the film-forming process of the third conductive layer is different from that of the first conductive layer, the third conductive layer is located in the hollow portions and covers the second conductive layer;

[0019] Remove the photoresist layer and the first conductive layer located under the photoresist layer;

[0020] Perform a curing eutectic treatment on the third conductive layer, the second conductive layer and the remaining first conductive layer, so that the second conductive layer is fixedly connected to the first conductive layer and the third conductive layer respectively.

[0021] Optionally, the height of the photoresist layer is greater than the height of the third conductive layer.

[0022] By providing the groove on the first conductive layer in this application, the area of the joint region between the first conductive layer and the second conductive layer can be increased, and the adhesion ability and fixing effect between the first conductive layer and the second conductive layer can be improved. Description of the Drawings

[0023] Figure 1 It is a schematic structural diagram of a driving backplane in a display device provided by an embodiment of this application;

[0024] Figure 2 It is a schematic diagram of the manufacturing process of a driving backplane in a display device provided by an embodiment of this application;

[0025] Figure 3 It is a schematic structural diagram of the driving backplane corresponding to step S01 provided by an embodiment of this application;

[0026] Figure 4 It is a schematic structural diagram of the driving backplane corresponding to step S02 provided by an embodiment of this application;

[0027] Figure 5 It is a schematic structural diagram of the driving backplane corresponding to step S03 provided by an embodiment of this application;

[0028] Figure 6 It is a schematic structural diagram of the driving backplane corresponding to step S04 provided by an embodiment of this application;

[0029] Figure 7 It is a schematic structural diagram of the driving backplane corresponding to step S05 provided by an embodiment of this application;

[0030] Figure 8 It is a schematic structural diagram of the driving backplane corresponding to step S06 provided by an embodiment of this application. Detailed Description of the Invention

[0031] Next, the technical solutions in the embodiments of this application will be clearly and completely described in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative efforts belong to the scope of protection of this application. In addition, it should be understood that the specific implementation manners described herein are only used to illustrate and explain this application, and are not used to limit this application. In this application, unless otherwise stated, the orientation words such as "upper" and "lower" usually refer to the upper and lower in the actual use or working state of the device, specifically the drawing direction in the drawings; and "inner" and "outer" refer to the outline of the device.

[0032] The following disclosure provides many different embodiments or examples for implementing different structures of the present application. To simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present application. In addition, the present application may repeat reference numerals and / or reference letters in different examples. This repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides examples of various specific processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials. The following will be described in detail respectively. It should be noted that the description order of the following embodiments does not limit the preferred order of the embodiments.

[0033] Figure 1 The following is a schematic structural diagram of a driving backplane in the display device provided by the embodiment of the present application. Referring to Figure 1 On the one hand, the present application provides a display device, which includes a plurality of light-emitting diodes (LEDs) arranged in an array. Specifically, the display device can be an active or passive light-emitting M-LED display device. The M-LED includes sub-millimeter light-emitting diodes (Mini-LED) and micro light-emitting diodes (Micro-LED). That is, the light-emitting diodes in the M-LED display device provided by the present application can serve both as display units for performing display functions and as light-emitting units for performing backlight functions. The present application does not limit the functions and sizes of the LEDs.

[0034] In this embodiment, the display device includes a driving backplane, and the driving backplane includes the plurality of light-emitting diodes arranged in an array. Correspondingly, the driving backplane can serve both as a display substrate and as a backlight substrate.

[0035] Specifically, the driving backplane further includes a substrate 10 and traces disposed on the substrate 10. Among them, the substrate 10 is used to carry the traces and the light-emitting diodes, and its material can be glass, plastic, etc.; the traces are electrically connected to the light-emitting diodes and are used to transmit electrical signals to the light-emitting diodes.

[0036] In this embodiment, the driving backplane further includes, for example, a driving IC, which is electrically connected to the trace and the light-emitting diode respectively. The setting of the driving IC can better control the light emission of the light-emitting diode while eliminating the problem of low reliability of the transistor driving method caused by immature technology development. However, at the same time, when the driving IC drives each light-emitting diode to emit light, it has a high requirement for the driving current. Therefore, there is a high requirement for the large-current transmission ability of the trace for transmitting electrical signals. One of the effective ways to improve the large-current transmission ability of the trace is to increase the thickness of the trace. However, due to the limitation of the film-forming technology, it is often difficult to directly form a metal trace that meets the thickness requirement. And even if a metal trace that meets the thickness requirement is finally formed, the metal trace often has problems such as poor adhesion and stress warping.

[0037] To solve the above problems, the present application provides a display device, which includes: a substrate 10 and a trace disposed on the substrate 10;

[0038] Wherein, the trace includes a first conductive layer 30, a second conductive layer 40, and a third conductive layer 50 that are sequentially stacked on the substrate 10. The second conductive layer 40 is fixedly connected to the first conductive layer 30 and the third conductive layer 50 respectively, and a plurality of grooves 31 are provided on one side of the first conductive layer 30 close to the second conductive layer 40, and at least a part of the second conductive layer 40 is disposed in the grooves 31.

[0039] In the present application, the trace is set as a multi-layer structure arranged in layers, and the first conductive layer 30, the second conductive layer 40, and the third conductive layer 50 in the multi-layer structure are fixedly connected to each other, thus effectively solving the problem that the thickness is difficult to reach the required specification due to poor film-forming technology. And because a plurality of grooves 31 are provided on one side of the first conductive layer 30 close to the second conductive layer 40, and at least a part of the second conductive layer 40 is disposed in the grooves 31, the setting of the grooves 31 increases the surface area of one side of the first conductive layer 30 close to the second conductive layer 40, so that the area of the bonding region between the first conductive layer 30 and the second conductive layer 40 can be greatly increased during the subsequent curing process, and at the same time, a pinning effect is generated, improving the adhesion ability and fixing effect between the first conductive layer 30 and the second conductive layer 40.

[0040] In this embodiment, the first conductive layer 30 has a plurality of grooves 31, and the depth of any one of the grooves 31 is less than the maximum thickness of the first conductive layer 30. Since each of the grooves 31 does not directly penetrate the first conductive layer 30, the grooves 31 of this structure have a larger sidewall area compared to the grooves that directly penetrate the first conductive layer 30. Thus, the surface area of the side of the first conductive layer 30 close to the second conductive layer 40 can be further increased, enhancing the eutectic effect between the first conductive layer 30 and the second conductive layer 40 in subsequent process steps, and further improving the adhesion ability and fixing effect between the first conductive layer 30 and the second conductive layer 40. Preferably, the depth of any one of the grooves 31 is 1 / 4 to 3 / 4 of the maximum thickness of the first conductive layer 30. Of course, the present application does not limit the arrangement form of the grooves 31. In other embodiments of the present application, at least some of the grooves 31 may also directly penetrate the first conductive layer 30.

[0041] In this embodiment, a plurality of the traces are provided on the substrate 10, and the traces are spaced apart from each other. Moreover, the vertical projections of the first conductive layer 30, the second conductive layer 40, and the third conductive layer 50 on the substrate 10 overlap each other, so that the traces have a better shape and the spacing between the traces is ensured to prevent short circuits.

[0042] In this embodiment, the groove 31 has an arc-shaped surface, which can, while ensuring a relatively low process difficulty, maximize the surface area of each groove 31 as much as possible, and improve the adhesion ability and fixing effect between the first conductive layer 30 and the second conductive layer 40.

[0043] In this embodiment, each trace corresponds to at least one groove 31. The extending direction of the groove 31 is, for example, the same as the extending direction of the trace, that is, the length direction of the groove 31 is the same as the length direction of the trace. Correspondingly, the width direction of the trace is the same as the width direction of the groove 31, and the thickness (or height) direction of the trace is the same as the thickness (or height) direction of the groove 31.

[0044] In this embodiment, the width of each of the traces is greater than or equal to the width of the groove 31 in the trace. Specifically, the first conductive layer 30 in at least one of the traces includes at least one groove 31 and planarization structures on both sides of any one of the grooves 31. The planarization structures are adjacently arranged with the groove 31, and the thickness of the planarization structure is also the maximum thickness of the first conductive layer 30. Since planarization structures are provided on both sides of the groove 31 in the first conductive layer 30, it is possible to reduce the manufacturing difficulty of the groove 31 while ensuring the width of the trace and improving the adhesion ability and fixing effect between the first conductive layer 30 and the second conductive layer 40.

[0045] In this embodiment, at least a part of the second conductive layer 40 is located outside the groove 31, that is, the second conductive layer 40 protrudes from the groove 31. Specifically, the surface of the second conductive layer 40 in each of the traces close to the third conductive layer 50 protrudes from the groove 31. As described above, the second conductive layer 40 is fixedly connected to the first conductive layer 30 and the third conductive layer 50 respectively, that is, the second conductive layer 40 is a connection carrier for the first conductive layer 30 and the third conductive layer 50. In this application, by arranging at least a part of the second conductive layer 40 outside the groove 31, it is possible to prevent the third conductive layer 50 and the first conductive layer 30 from directly contacting and ensure the fixing effect between the first conductive layer 30 and the third conductive layer 50.

[0046] In this embodiment, the maximum thickness of the third conductive layer 50 is less than the maximum thickness of the first conductive layer 30, that is, the third conductive layer 50 is thinner than the first conductive layer 30. The thinner the film layer, the less likely it is to undergo stress warping, and the better the adhesion ability and fixing effect of the film layer. Since the third conductive layer 50 is thinner than the first conductive layer 30, therefore, the third conductive layer 50 does not need to have a special structure design on the side close to the second conductive layer 40, which can reduce the process difficulty during the production of the trace and reduce the cost.

[0047] In this embodiment, the material of the first conductive layer 30 is the same as that of the third conductive layer 50. Due to the limitation of the existing film forming process, the routing formed by the first conductive layer 30 alone cannot meet the fixed thickness requirement. The present application solves the problem of poor high current output capacity due to the thickness not meeting the requirement by stacking the third conductive layer 50 of the same material as the first conductive layer 30 on the first conductive layer 30 and connecting the two fixedly through the second conductive layer 40. In addition, since the third conductive layer 50 and the first conductive layer 30 are made of the same material, the conductive performance of the routing can be ensured while reducing the types of materials and the material cost. Preferably, the material of the first conductive layer 30 and the third conductive layer 50 is a metal element or a metal alloy, and the metal material constituting the metal element and the metal alloy includes: at least one of copper, silver or gold. Of course, the present application does not limit the material of the first conductive layer 30 and the third conductive layer 50. In other embodiments of the present application, the material of the first conductive layer 30 and the third conductive layer 50 can also be different.

[0048] In this embodiment, the second conductive layer 40 is made of different materials from the first conductive layer 30 and the third conductive layer 50 . The second conductive layer 40 is, for example, an electroplating material, such as tin (Sn) or a tin alloy.

[0049] In this embodiment, the display device includes a eutectic structure, and the eutectic structure is formed between the first conductive layer 30 and the second conductive layer 40 ; and the eutectic structure is formed between the third conductive layer 50 and the second conductive layer 40 .

[0050] Specifically, the eutectic structure includes a first fixed connection layer 60 formed between the first conductive layer 30 and the second conductive layer 40 , and a second fixed connection layer 70 formed between the second conductive layer 40 and the third conductive layer 50 .

[0051] In this embodiment, the first fixed connection layer 60 is used to join and fixedly connect the first conductive layer 30 and the second conductive layer 40, and the second fixed connection layer 70 is used to join and fixedly connect the third conductive layer 50 and the second conductive layer 40. Among them, the contact area between the first fixed connection layer 60 and the second conductive layer 40 is larger than the contact area between the second fixed connection layer 70 and the second conductive layer 40, and the contact area between the first fixed connection layer 60 and the first conductive layer 30 is larger than the contact area between the second fixed connection layer 70 and the third conductive layer 50. As mentioned above, the maximum thickness of the first conductive layer 30 is greater than the maximum thickness of the third conductive layer 50. Therefore, it is easier for the first conductive layer 30 to peel off and fall off from other film layers. By setting the form of the groove 31, the area of the first fixed connection layer 60 can be effectively increased, and a pinning effect is generated, thereby improving the adhesion ability and fixing effect between the first conductive layer 30 and the second conductive layer 40.

[0052] In this embodiment, to ensure the fixing effect between the first conductive layer 30 and the second conductive layer 40, a plurality of protrusions with the same number as the grooves 31 are provided on the side of the second conductive layer 40 close to the first conductive layer 30. Each of the protrusions is correspondingly located in each of the grooves 31, and each of the protrusions is fixedly connected to each of the grooves 31 through the first fixed connection layer 60.

[0053] In this embodiment, the surface of the side of the second conductive layer 40 close to the third conductive layer 50 is a flat surface. As mentioned above, since the maximum thickness of the third conductive layer 50 is less than the maximum thickness of the first conductive layer 30, even if the surface of the side of the second conductive layer 40 close to the third conductive layer 50 is a flat surface, a good fixing effect between the third conductive layer 50 and the second conductive layer 40 can still be ensured. Of course, the present application does not limit the form of the surface of the side of the second conductive layer 40 close to the third conductive layer 50. In other embodiments of the present application, the surface of the side of the second conductive layer 40 close to the third conductive layer 50 may also be an uneven non-flat surface.

[0054] Figure 2 It is a schematic diagram of the manufacturing process of the driving backplane in the display device provided by the embodiment of the present application. Figure 3 It is a schematic diagram of the structure of the driving backplane corresponding to step S01 provided by the embodiment of the present application; Figure 4 It is a schematic diagram of the structure of the driving backplane corresponding to step S02 provided by the embodiment of the present application; Figure 5 It is a schematic diagram of the structure of the driving backplane corresponding to step S03 provided by the embodiment of the present application; Figure 6Schematic diagram of the driving backplane corresponding to step S04 provided by an embodiment of the present application; Figure 7 Schematic diagram of the driving backplane corresponding to step S05 provided by an embodiment of the present application; Figure 8 Schematic diagram of the driving backplane corresponding to step S06 provided by an embodiment of the present application. Refer to Figures 2 - 8 The present application further provides a method for manufacturing a display device for manufacturing the driving backplane in the aforementioned display device.

[0055] Specifically, the method for manufacturing the display device includes the following steps:

[0056] S01: Provide a substrate 10 and form a first conductive layer 30. The first conductive layer 30 is disposed on the substrate 10, and a plurality of grooves 31 are provided on a side of the first conductive layer 30 away from the substrate 10;

[0057] S02: Form a photoresist layer 80. The photoresist layer 80 is disposed on the first conductive layer 30 and is formed with a plurality of hollow portions 81. The hollow portions 81 surround the grooves 31;

[0058] S03: Form a second conductive layer 40. At least a part of the second conductive layer 40 is located in the grooves 31;

[0059] S04: Form a third conductive layer 50. The film-forming process of the third conductive layer 50 is different from that of the first conductive layer 30. The third conductive layer 50 is located in the hollow portions 81 and covers the second conductive layer 40;

[0060] S05: Remove the photoresist layer 80 and the first conductive layer 30 located below the photoresist layer 80;

[0061] S06: Perform a curing eutectic treatment on the third conductive layer 50, the second conductive layer 40, and the remaining first conductive layer 30 so that the second conductive layer 40 is fixedly connected to the first conductive layer 30 and the third conductive layer 50 respectively.

[0062] In the step S01, the first conductive layer 30 is formed by a film-forming process of physical vapor deposition (PVD). By using a half-tone process, through exposure, development, etching, and stripping processes on the first conductive layer 30, a plurality of grooves 31 are formed on the first conductive layer 30. Further, the substrate 10 is made of glass; the material of the first conductive layer 30 is, for example, a single metal or a metal alloy, and the thickness is 0.2 - 1 μm. At the same time, in order to improve the film-forming quality of the first conductive layer 30 on the substrate 10, a molybdenum (Mo) layer 20 is, for example, further provided between the substrate 10 and the first conductive layer 30, and the thickness of the Mo layer 20 is controlled within 0.1 - 0.2 μm.

[0063] In the above step S02, the height of the photoresist layer 80 is greater than the height of the third conductive layer 50 formed in the subsequent process. By exposing and developing the photoresist layer 80, the photoresist layer 80 with the hollow portion 81 is formed. Since the height of the photoresist layer 80 is higher than that of the third conductive layer 50, during the subsequent film-forming process of the third conductive layer 50, the photoresist layer 80 can prevent the third conductive layer 50 from extending outward, avoiding the third conductive layer 50 from becoming an inverted trapezoid shape. Further, the area of the hollow portion 81 is greater than the area of the groove 31, the length of the hollow portion 81 is greater than the length of the groove 31, and the width of the hollow portion 81 is greater than the width of the groove 31.

[0064] In the above step S03, the second conductive layer 40 can be formed on the first conductive layer 30 by an electroplating process. Specifically, the material of the second conductive layer 40 is, for example, tin or a tin alloy. The second conductive layer 40 fills the groove 31 and is at least partially located within the hollow portion 81, and the area of the second conductive layer 40 located within the hollow portion 81 is the same as the area of the hollow portion 81, so as to prevent the third conductive layer 50 from directly bonding to the first conductive layer 30 during the subsequent film-forming process and ensure the fixing effect between the first conductive layer 30 and the third conductive layer 50.

[0065] In the above step S04, the third conductive layer 50 can be formed on the second conductive layer 40 by an electroplating process. The additionally provided third conductive layer 50 can compensate for the problem of poor wire conductivity caused by the insufficient thickness of the first conductive layer 30. Further, the material of the third conductive layer 50 is the same as that of the first conductive layer 30, the maximum thickness of the third conductive layer 50 is less than the maximum thickness of the first conductive layer 30, and the height of the third conductive layer 50 is lower than the height of the photoresist layer 80.

[0066] In the above step S05, the photoresist layer 80 is removed by a stripping process, and the first conductive layer 30 located under the photoresist layer 80 is removed by an etching process, and the first conductive layer 30 directly under the third conductive layer 50 and the second conductive layer 40 is retained. The etching rate of the first conductive layer 30 is maintained at 30 to 300 Å / s, aiming to improve the controllability of the etching of the first conductive layer 30, ensure the etching pattern, and avoid excessive etching from affecting the process requirements.

[0067] In the above step S06, through a curing eutectic process, a first fixed connection layer 60 is formed between the first conductive layer 30 and the second conductive layer 40. The material of the first fixed connection layer 60 is, for example, Cu3Sn and Cu6Sn5; a second fixed connection layer 70 is formed between the third conductive layer 50 and the second conductive layer 40, and the material of the second fixed connection layer 70 is the same as that of the first fixed connection layer 60. The curing eutectic process includes at least one of vacuum reflow, hot pressing, and laser heating.

[0068] In the above method for manufacturing a display device, for example, it further includes step S07: forming a driving IC and a light-emitting unit on the substrate 10 through an SMT process.

[0069] In summary, the present application provides a display device and a manufacturing method thereof. The display device includes: a substrate and traces disposed on the substrate; wherein, the traces include a first conductive layer, a second conductive layer, and a third conductive layer sequentially stacked on the substrate. The second conductive layer is fixedly connected to the first conductive layer and the third conductive layer respectively, and a plurality of grooves are provided on one side of the first conductive layer close to the second conductive layer, and at least a part of the second conductive layer is disposed in the grooves. By providing the grooves on the first conductive layer, the present application can increase the area of the bonding region between the first conductive layer and the second conductive layer, and improve the adhesion ability and fixing effect between the first conductive layer and the second conductive layer.

[0070] The above has introduced in detail a display device and a manufacturing method thereof provided by the embodiments of the present application. Specific examples are used in this article to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those skilled in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A display device, characterized in that, The display device includes: a substrate; a trace disposed on the substrate; wherein, the trace includes a first conductive layer, a first fixed connection layer, a second conductive layer, a second fixed connection layer, and a third conductive layer that are sequentially stacked on the substrate, the first fixed connection layer connects the first conductive layer and the second conductive layer, the second fixed connection layer connects the second conductive layer and the third conductive layer, and a plurality of grooves are provided on a side of the first conductive layer close to the second conductive layer, the first fixed connection layer is located in the grooves, at least a part of the second conductive layer is disposed in the grooves, the material of the first conductive layer is the same as the material of the third conductive layer, the first conductive layer includes at least one of copper, silver, and gold, and the second conductive layer includes tin or a tin alloy.

2. The display device according to claim 1, wherein The depth of any one of the grooves is less than the maximum thickness of the first conductive layer, and the maximum thickness of the third conductive layer is less than the maximum thickness of the first conductive layer.

3. The display device according to claim 1, wherein The display device further includes a molybdenum layer, the molybdenum layer is located between the trace and the substrate and contacts the first conductive layer of the trace.

4. The display device according to claim 1, wherein Both the first fixed connection layer and the second fixed connection layer are eutectic structures.

5. The display device according to claim 1, wherein The extending direction of the grooves is the same as the extending direction of the trace, and the grooves have an arc-shaped surface.

6. The display device according to claim 1, wherein The contact area between the first fixed connection layer and the second conductive layer is greater than the contact area between the second fixed connection layer and the second conductive layer, and the contact area between the first fixed connection layer and the first conductive layer is greater than the contact area between the second fixed connection layer and the third conductive layer.

7. The display device according to claim 6, characterized in that, A plurality of protrusions having the same number as the grooves are provided on a side of the second conductive layer close to the first conductive layer, and each of the protrusions is correspondingly located in each of the grooves.

8. The display device according to claim 6, wherein The surface of the side of the second conductive layer close to the third conductive layer is a flat surface.

9. A method for preparing a display device, characterized in that, including the following steps: providing a substrate and forming a first conductive layer, the first conductive layer is disposed on the substrate, and a plurality of grooves are provided on a side of the first conductive layer away from the substrate, and the first conductive layer includes at least one of copper, silver, and gold; forming a photoresist layer, the photoresist layer is disposed on the first conductive layer and is formed with a plurality of hollow portions surrounding the grooves; forming a second conductive layer, at least a part of the second conductive layer is located in the grooves, and the second conductive layer includes tin or a tin alloy; forming a third conductive layer, the film forming process of the third conductive layer is different from that of the first conductive layer, the third conductive layer is located in the hollow portions and covers the second conductive layer, and the material of the first conductive layer is the same as the material of the third conductive layer; removing the photoresist layer and the first conductive layer located under the photoresist layer; performing a curing eutectic treatment on the third conductive layer, the second conductive layer, and the remaining first conductive layer to form a first fixed connection layer between the first conductive layer and the second conductive layer and form a second fixed connection layer between the third conductive layer and the second conductive layer.

10. The method for manufacturing a display device according to claim 9, characterized in that, The height of the photoresist layer is greater than the height of the third conductive layer.

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