Display panel and method for manufacturing the same

Abstract

The present application provides a display panel and a manufacturing method thereof; the display panel includes a substrate, an auxiliary electrode disposed on the substrate, an undercut metal layer insulatingly disposed on the auxiliary electrode, a via hole disposed on the undercut metal layer, and a cathode layer insulatingly disposed on the undercut metal layer. The via hole penetrates the undercut metal layer along the light-emitting direction of the display panel and extends to the surface of the auxiliary electrode. The undercut metal layer includes a first metal portion and a second metal portion located on both sides of the via hole, at least a part of the first metal portion is located in the via hole, and the cathode layer extends through the via hole to be connected to the auxiliary electrode; by replacing the organic / inorganic insulating film layer on the auxiliary electrode for forming the undercut structure with an undercut metal layer, the etching acid solution used in the undercut process can also be correspondingly replaced by a metal acid solution, thereby avoiding or reducing the corrosion of the glass substrate caused by hydrofluoric acid (HF), which is beneficial to improving the product yield of OLED devices.

Description

Technical Field

[0001] This application relates to the field of display technologies, and particularly to a display panel and a manufacturing method thereof. Background Art

[0002] In order to reduce the voltage drop and minimize the display brightness difference, OLED display devices usually set up an auxiliary cathode. By overlapping the auxiliary cathode with the cathode layer, resistance parallel connection is achieved, thereby reducing the voltage drop of the cathode layer and improving the display effect. At present, the overlapping of the auxiliary electrode and the cathode layer is usually achieved by forming an undercut structure through an undercut process. When forming the cathode layer, a laterally etched part can be plated in, so as to overlap with the underlying auxiliary cathode and realize the electrical connection between the cathode layer and the auxiliary electrode.

[0003] Current undercut processes all etch the organic / inorganic insulating film layer on the auxiliary electrode through hydrofluoric acid (HF) to expose the auxiliary electrode for overlapping with the cathode layer. However, HF will also corrode the glass substrate of the OLED display device, reducing the product yield of the OLED device to a certain extent. Summary of the Invention

[0004] This application provides a display panel and a manufacturing method thereof to improve the technical problem of the reduction in product yield caused by the corrosion of the glass substrate when the current OLED display device uses hydrofluoric acid for the undercut process.

[0005] To solve the above technical problem, the technical solution provided by this application is as follows:

[0006] This application provides a display panel, including:

[0007] A substrate;

[0008] An auxiliary electrode disposed on the substrate;

[0009] An undercut metal layer insulatingly disposed on the auxiliary electrode;

[0010] An overlapping hole penetrating the undercut metal layer along the light-emitting direction of the display panel, and the overlapping hole extends to the surface of the auxiliary electrode; and

[0011] A cathode layer insulatingly disposed on the undercut metal layer;

[0012] Wherein, the undercut metal layer includes a first metal part and a second metal part located on both sides of the overlapping hole, at least part of the first metal part is located within the overlapping hole, and the cathode layer extends through the overlapping hole to be connected to the auxiliary electrode.

[0013] In the display panel of this application, the undercut metal layer includes a sacrificial layer and shielding layers located on both sides of the sacrificial layer;

[0014] Wherein, the corrosion rate of the sacrificial layer is greater than that of the shielding layer.

[0015] In the display panel of the present application, in the first metal part, an undercut groove is formed between the sacrificial layer and the shielding layers on both sides, and the undercut groove communicates with the overlapping hole.

[0016] In the display panel of the present application, in the first metal part, the side of the sacrificial layer away from the overlapping hole is flush with the side of the shielding layer away from the overlapping hole.

[0017] In the display panel of the present application, the second metal part is separated from the overlapping hole, and the area of the sacrificial layer of the second metal part is equal to the area of the shielding layer of the second metal part.

[0018] In the display panel of the present application, the display panel further includes a passivation layer disposed on the undercut metal layer, and the passivation layer includes a first passivation part disposed on the first metal part and a second passivation part disposed on the second metal part;

[0019] The first passivation part and the second passivation part are located on both sides of the overlapping hole.

[0020] In the display panel of the present application, the first passivation part covers the side of the first metal part away from the overlapping hole, the second passivation part covers the entire second metal part, and the cathode layer covers the surface of the second passivation part close to the overlapping hole.

[0021] In the display panel of the present application, the display panel further includes a planarization layer disposed on the passivation layer, and the cathode layer is disposed on the planarization layer;

[0022] Wherein, the orthographic projection of the planarization layer on the undercut metal layer does not coincide with the first metal part and the second metal part.

[0023] In the display panel of the present application, the display panel further includes at least one thin film transistor, and the undercut metal layer is disposed on the same layer as the source-drain layer of the thin film transistor.

[0024] The present application also provides a method for manufacturing a display panel, including:

[0025] Providing a substrate;

[0026] Forming an auxiliary electrode on the substrate;

[0027] Forming an undercut metal layer on the auxiliary electrode, which is insulated from the auxiliary electrode;

[0028] Etch the undercut metal layer using a copper acid to form a lap hole extending to the surface of the auxiliary electrode;

[0029] Form an insulating cathode layer on the undercut metal layer, and lap the cathode layer with the auxiliary electrode through the lap hole.

[0030] Beneficial effects

[0031] In this application, the organic / inorganic insulating film layer on the auxiliary electrode used to form the undercut structure in the traditional OLED display device is replaced with an undercut metal layer, so that the etching acid solution used in the undercut process can also be correspondingly replaced with a metal acid solution by hydrofluoric acid (HF), thereby avoiding or reducing the corrosion of the glass substrate caused by hydrofluoric acid (HF), which is beneficial to improving the product yield of the OLED device. Description of the drawings

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0033] Figure 1 It is a schematic diagram of the stacked structure of the display panel described in the present application;

[0034] Figure 2 It is a flowchart of the manufacturing method of the display panel described in the present application;

[0035] Figures 3 to 7 It is a schematic diagram of the manufacturing process of the display panel described in the present application;

[0036] Description of reference numerals:

[0037] 100, substrate;

[0038] 200, auxiliary electrode;

[0039] 300, insulating buffer layer;

[0040] 400, undercut metal layer; 401, sacrificial layer; 402, shielding layer; 403, undercut groove; 410, first metal part; 420, second metal part; 430, lap hole; 440, source-drain layer;

[0041] 500, passivation layer; 510, first passivation part; 520, second passivation part; 530, first interlayer via;

[0042] 600, planarization layer; 610, second interlayer via;

[0043] 700, cathode layer. Detailed implementation manners

[0044] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present application. In addition, it should be understood that the specific implementation manners described herein are only used to illustrate and explain the present application, and are not used to limit the present application. In the present application, unless otherwise stated, the orientation terms such as "upper" and "lower" generally refer to the upper and lower in the actual use or working state of the device, specifically the drawing direction in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0045] At present, in OLED display devices, the lap joint between the auxiliary electrode and the cathode layer is usually formed by a bottom cutting process to form a bottom cutting structure. The current bottom cutting processes all etch the organic / inorganic insulating film layer on the auxiliary electrode with hydrofluoric acid (HF) to expose the auxiliary electrode for the lap joint of the cathode layer. However, HF will also corrode the glass substrate of the OLED display device, reducing the product yield of the OLED device to a certain extent. The present application proposes the following solutions based on the above technical problems.

[0046] Please refer to Figure 1 , the present application provides a display panel, including a substrate 100, an auxiliary electrode 200 disposed on the substrate 100, a bottom cutting metal layer 400 insulatingly disposed on the auxiliary electrode 200, a lap joint hole 430 disposed on the bottom cutting metal layer 400, and a cathode layer 700 insulatingly disposed on the bottom cutting metal layer 400. The lap joint hole 430 penetrates the bottom cutting metal layer 400 along the light emitting direction of the display panel, and the lap joint hole 430 extends to the surface of the auxiliary electrode 200. The bottom cutting metal layer 400 includes a first metal part 410 and a second metal part 420 located on both sides of the lap joint hole 430, at least part of the first metal part 410 is located in the lap joint hole 430, and the cathode layer 700 extends through the lap joint hole 430 to be connected to the auxiliary electrode 200.

[0047] In the present application, by replacing the organic / inorganic insulating film layer on the auxiliary electrode 200 used to form the bottom cutting structure in the traditional OLED display device with the bottom cutting metal layer 400, the etching acid solution used in the bottom cutting process can also be correspondingly replaced from hydrofluoric acid (HF) with a metal acid solution, thereby avoiding or reducing the corrosion of the glass substrate caused by hydrofluoric acid (HF), and at the same time, avoiding or reducing subsequent abnormal laser lift-off processes and abnormal vacuum suction of the substrate by the stage equipment, which is beneficial to improving the product yield of the OLED device.

[0048] The technical solution of the present application will be described in combination with specific embodiments. It should be noted that the description order of the following embodiments does not limit the preferred order of the embodiments.

[0049] In this embodiment, the substrate 100 may be a substrate bottom material such as a glass substrate, a polyimide substrate, or a polyester substrate. The auxiliary electrode 200, the undercut metal layer 400, and the cathode layer 700 may be made of conductive metal materials.

[0050] In this embodiment, the display panel may further include an insulating buffer layer 300 disposed between the auxiliary electrode 200 and the undercut metal layer 400. The auxiliary electrode 200 is disposed on the insulating buffer layer 300, and the undercut metal layer 400 and the auxiliary electrode 200 are insulated from each other through the insulating buffer layer 300. The overlapping hole 430 may penetrate through the insulating buffer layer 300 on the auxiliary electrode 200 and extend to the surface of the auxiliary electrode 200.

[0051] In this embodiment, the orthographic projection of the undercut metal layer 400 on the auxiliary electrode 200 may at least partially overlap with the auxiliary electrode 200, so that the undercut metal layer 400 can form an undercut structure and the overlapping hole 430 on the auxiliary electrode 200 through an undercut process, thereby realizing the connection between the cathode layer 700 and the auxiliary electrode 200.

[0052] In this embodiment, an interlayer via hole may be provided corresponding to the overlapping hole 430 on other insulating film layers between the undercut metal layer 400 and the cathode layer 700. The interlayer via hole may communicate with the overlapping hole 430 to form a connection channel for the cathode layer 700 to extend to the auxiliary electrode 200.

[0053] In this embodiment, "at least part of the first metal portion 410 is located in the overlapping hole 430" may be understood as: one side of the first metal portion 410 close to the overlapping hole 430 may extend into the overlapping hole 430. At this time, one side of the first metal portion 410 close to the overlapping hole 430 is not covered by the film layer but is exposed to the external environment, so that an undercut structure can be formed on one side of the first metal portion 410 close to the overlapping hole 430 by means of a metal acid solution through an undercut process.

[0054] Please refer to Figure 1, in the display panel of the present application, the display panel may include a plurality of opening areas arranged in an array and a non-opening area located at least on one side of the opening area. A light-emitting device is disposed in the opening area, and the auxiliary electrode 200, the undercut metal layer 400, and the overlapping hole 430 are disposed in the non-opening area to avoid reducing the aperture ratio of the display panel due to the arrangement of the auxiliary electrode 200, the undercut metal layer 400, and the overlapping hole 430, and to maintain a good display effect of the display panel.

[0055] In this embodiment, the light-emitting device may include an anode layer, an organic light-emitting layer disposed on the anode layer, and the cathode layer 700 disposed on the organic light-emitting layer. The anode layer and the organic light-emitting layer of the light-emitting device are disposed in the opening area, and the cathode layer 700 of the light-emitting device extends to the non-opening area and forms a whole-surface film layer structure.

[0056] In this embodiment, the display panel may further include a thin-film transistor disposed on the substrate 100 in the non-opening area, and the anode layer of the light-emitting device may be electrically connected to the source or drain of the thin-film transistor. The undercut metal layer 400 may be disposed on the same layer as the source-drain layer 440 of the thin-film transistor. Specifically, the undercut metal layer 400 and the source-drain layer 440 of the thin-film transistor may be fabricated in the same process through the same metal material layer to reduce unnecessary film layer arrangements and simplify the manufacturing process of the display panel, which is beneficial to the thinning and low-cost manufacturing of the display panel.

[0057] Please refer to Figure 1 , in the display panel of the present application, the undercut metal layer 400 may include a sacrificial layer 401 and shielding layers 402 located on both sides of the sacrificial layer 401. Specifically, the undercut metal layer 400 may include at least three film layer structures, and these three film layers are stacked along the light-emitting direction of the display panel. The sacrificial layer 401 is located in the middle, and the shielding layers 402 are located on both sides.

[0058] In this embodiment, the corrosion rate of the sacrificial layer 401 needs to be greater than the corrosion rate of the shielding layer 402. Therefore, when etching the undercut metal layer 400 with metal acid solution, the sacrificial layer 401 in the middle corrodes faster, forming an "inward" concave structure. It should be noted that "inward" here means that the sacrificial layer 401 in the middle is recessed compared with the shielding layers 402 on both sides, or in other words, the shielding layers 402 on both sides extend compared with the sacrificial layer 401 in the middle.

[0059] In this embodiment, the undercut metal layer 400 may be a laminated structure of three layers of metal MoTi / Cu / MoTi. Among them, Cu is located in the middle as the sacrificial layer 401, and two layers of MoTi are located on both sides of Cu as the shielding layer 402. Correspondingly, the metal acid solution used in the undercut process may be copper acid, and the corrosion rate of Cu in copper acid is greater than that of MoTi in copper acid, so that an undercut structure can be formed.

[0060] In this embodiment, since the undercut metal layer 400 may be provided on the same layer as the source-drain electrode layer 440 of the thin film transistor, therefore, the material of the source-drain electrode layer 440 of the thin film transistor may also be a laminated structure of MoTi / Cu / MoTi.

[0061] It should be noted that in this embodiment, the undercut metal layer 400 may also be a stack of metal film layers of other different materials, and an undercut structure is formed by etching with a metal acid solution that can corrode the intermediate metal material. This embodiment only takes the laminated structure of MoTi / Cu / MoTi as an example for illustration, and does not represent a limitation on other laminated structures that can achieve the same effect.

[0062] Please refer to Figure 1 , in the display panel of the present application, in the first metal portion 410, an undercut groove 403 may be formed between the sacrificial layer 401 and the shielding layers 402 on both sides. Specifically, as described above, the corrosion rate of the sacrificial layer 401 located in the middle is faster, and the "inward" concave structure formed is the undercut groove 403. Here, "inward" means that the sacrificial layer 401 located in the middle is retracted compared with the shielding layers 402 located on both sides, or in other words, the shielding layers 402 located on both sides extend outwards compared with the sacrificial layer 401 located in the middle.

[0063] In this embodiment, the undercut groove 403 is located on one side where the first metal portion 410 extends to the overlapping hole 430, and the undercut groove 403 may communicate with the overlapping hole 430. In other words, the undercut groove 403 is formed by the side where the first metal portion 410 extends to the overlapping hole 430 being corroded by copper acid when exposed to the external environment.

[0064] Please refer to Figure 1, in the display panel of the present application, the display panel may further include a passivation layer 500 disposed on the undercut metal layer 400 and the insulating buffer layer 300, and the passivation layer 500 is disposed between the undercut metal layer 400 and the cathode layer 700. Specifically, the passivation layer 500 may include a first passivation portion 510 disposed on the first metal portion 410 and a second passivation portion 520 disposed on the second metal portion 420. Correspondingly to the first metal portion 410 and the second metal portion 420, the first passivation portion 510 and the second passivation portion 520 may be located on both sides of the overlapping hole 430. The passivation layer 500 can achieve insulation between the cathode layer 700 and the undercut metal layer 400, avoiding or reducing current loss caused by the connection between the cathode layer 700 and the undercut metal layer 400 at the overlapping hole 430, and reducing power consumption.

[0065] In this embodiment, the first passivation portion 510 may cover the side of the first metal portion 410 away from the overlapping hole 430. Specifically, in the first metal portion 410, the side of the sacrificial layer 401 away from the overlapping hole 430 and the side of the shielding layer 402 away from the overlapping hole 430 may be flush with each other. At this time, the side of the first metal portion 410 away from the overlapping hole 430 is protected by the first passivation portion 510 during the undercut process, and the side of the first metal portion 410 away from the overlapping hole 430 is not corroded by the metal acid solution, so that the edges of the sacrificial layer 401 and the shielding layer 402 can be kept flush.

[0066] In this embodiment, the second passivation portion 520 may cover the entire second metal portion 420. At this time, the second metal portion 420 is completely covered by the second passivation portion 520 to achieve complete isolation from the external environment. During the undercut process, the second metal portion 420 is protected by the second passivation portion 520 and is not corroded.

[0067] In this embodiment, since the second metal portion 420 is completely covered by the second passivation portion 520, it does not contact the overlapping hole 430. In other words, the second metal portion 420 and the overlapping hole 430 are separated by the second passivation portion 520, or the second metal portion 420 and the overlapping hole 430 are separately arranged. In this embodiment, because the entire second metal portion 420 is protected by the second passivation portion 520, neither the sacrificial layer 401 nor the shielding layer 402 of the second metal portion 420 is corroded by the metal acid solution. Therefore, the shapes and areas of the sacrificial layer 401 and the shielding layer 402 of the second metal portion 420 are also the same.

[0068] In this embodiment, the cathode layer 700 fabricated over the entire surface can be formed not only on the side of the passivation layer 500 away from the auxiliary electrode 200, but also on the surface of the second passivation portion 520 close to the overlapping hole 430. At this time, the cathode layer 700 formed on one side of the first metal portion 410 is disconnected at the undercut structure of the first metal portion 410, while the cathode layer 700 formed on one side of the second metal portion 420 is continuously disposed along the surface of the second passivation portion 520 to the surface of the auxiliary electrode 200, realizing electrical connection with the auxiliary electrode 200.

[0069] Please refer to Figure 1 , in the display panel of the present application, the display panel may further include a planarization layer 600 disposed on the passivation layer 500, and the cathode layer 700 may be disposed over the entire surface on the planarization layer 600.

[0070] In this embodiment, an interlayer via hole extending along the light-emitting direction of the display panel may be provided at the overlapping hole 430 position between the passivation layer 500 and the planarization layer 600. Specifically, a first interlayer via hole 530 may be provided at the overlapping hole 430 position in the passivation layer 500. The first interlayer via hole 530 may be provided on the passivation layer 500 on the undercut metal layer 400, and the first interlayer via hole 530 communicates with the overlapping hole 430. The first passivation portion 510 and the second passivation portion 520 of the passivation layer 500 are respectively located on both sides of the first interlayer via hole 530. A second interlayer via hole 610 may be provided at the overlapping hole 430 position in the planarization layer 600. The second interlayer via hole 610 may penetrate through the planarization layer 600 along the light-emitting direction of the display panel, and the second interlayer via hole 610 may communicate with the first interlayer via hole 530.

[0071] In this embodiment, the planar size of the second interlayer via hole 610 in the planarization layer 600 may be larger than the planar size of the first interlayer via hole 530 in the passivation layer 500, so that a stepped structure is formed between the planarization layer 600 and the passivation layer 500, facilitating continuous attachment of the cathode material when forming the cathode layer 700.

[0072] In this embodiment, the orthographic projection of the first interlayer via hole 530 on the undercut metal layer 400 partially overlaps with the first metal portion 410. In other words, a part of the surface of the first metal portion 410 close to the planarization layer 600 is exposed to the external environment, facilitating etching of the first metal portion 410 by metal acid solution.

[0073] In this embodiment, the orthographic projections of the first metal part 410 and the second metal part 420 within the flat layer 600 may be located within the second interlayer via 610. In other words, the orthographic projection of the flat layer 600 onto the undercut metal layer 400 does not coincide with the first metal part 410 and the second metal part 420, so as to ensure that the flat layer 600 does not cover the surface of the first metal part 410 exposed to the external environment, thereby avoiding or reducing any adverse effects of the flat layer 600 on the undercut process of the first metal part 410.

[0074] In this application, the organic / inorganic insulating film layer on the auxiliary electrode 200 used to form the undercut structure in the conventional OLED display device is replaced with the undercut metal layer 400, so that the etching acid solution used in the undercut process can also be correspondingly replaced from hydrofluoric acid (HF) with a metal acid solution, thereby avoiding or reducing the corrosion of the glass substrate caused by hydrofluoric acid (HF), and at the same time, it can also avoid or reduce abnormalities in the subsequent laser lift-off process and abnormal vacuum suction of the substrate by the carrier equipment, which is beneficial to improving the product yield of the OLED device.

[0075] Please refer to Figures 2 to 7 , this embodiment of the application also provides a method for manufacturing a display panel, including S100: providing a substrate 100, as Figure 3 shown.

[0076] S200: forming an auxiliary electrode 200 on the substrate 100, as Figure 4 shown.

[0077] S300: forming an undercut metal layer 400, which is insulated from the auxiliary electrode 200, on the auxiliary electrode 200, as Figure 5 shown.

[0078] S400: using a metal acid solution to undercut-etch the undercut metal layer 400 to form a lap hole 430 extending to the surface of the auxiliary electrode 200, as Figure 6 shown.

[0079] S500: forming an insulating cathode layer 700 on the undercut metal layer 400, and making the cathode layer 700 lap with the auxiliary electrode 200 through the lap hole 430, as Figure 7 shown.

[0080] In this application, by using a metal acid solution for undercut etching of the undercut metal layer 400 in the undercut process, on the one hand, the undercut metal layer 400 is formed with an undercut structure and a lap hole 430 for the cathode layer 700 to lap with the auxiliary electrode 200. On the other hand, the property that the metal acid solution cannot corrode the glass substrate can be utilized to play a good protective role for the substrate 100 made of glass substrate material, thereby avoiding or reducing the corrosion of the glass substrate caused by hydrofluoric acid (HF) in the traditional undercut process, and also avoiding or reducing the abnormalities in the subsequent laser lift-off process and the abnormal vacuum suction of the substrate by the stage equipment, which is beneficial to improving the product yield of the OLED device.

[0081] In this embodiment, the step S300 may include:

[0082] S310. Form an insulating buffer layer 300 on the auxiliary electrode 200, and cover the auxiliary electrode 200 with the buffer metal layer.

[0083] S320. Form an undercut metal material layer on the insulating buffer layer 300, and form the undercut metal layer 400 through patterning.

[0084] In this embodiment, the step S400 may include:

[0085] S410. Sequentially form a passivation layer 500 and a planarization layer 600 on the undercut metal layer 400.

[0086] S420. Form a second interlayer via 610 on the planarization layer 600 corresponding to the auxiliary electrode 200.

[0087] S430. Form a first interlayer via 530 on the passivation layer 500 corresponding to the auxiliary electrode 200.

[0088] S440. Etch the undercut metal layer 400 with a metal acid solution to form a lap hole 430 and an undercut structure penetrating the undercut metal layer 400.

[0089] S450. Form an interlayer via at the position of the insulating buffer layer 300 corresponding to the lap hole 430, so that the lap hole 430 communicates with this interlayer via and extends to the surface of the auxiliary electrode 200.

[0090] S460. Form a cathode layer 700 over the entire surface of the planarization layer 600, and make the cathode layer 700 extend through the lap hole 430 to be connected to the auxiliary electrode 200.

[0091] The above has introduced in detail a display panel 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 panel, characterized in that, Comprising: A substrate; An auxiliary electrode disposed on the substrate; An undercut metal layer insulatedly disposed on the auxiliary electrode; A via hole extending through the undercut metal layer along the light-emitting direction of the display panel, and the via hole extends to the surface of the auxiliary electrode; And A cathode layer insulatedly disposed on the undercut metal layer; Wherein, the undercut metal layer includes a first metal part and a second metal part located on both sides of the via hole, at least a part of the first metal part is located in the via hole, and the cathode layer extends through the via hole to be connected to the auxiliary electrode; the display panel further includes an insulating buffer layer and a passivation layer, the insulating buffer layer is disposed between the auxiliary electrode and the undercut metal layer, and the via hole penetrates through the insulating buffer layer; the passivation layer is disposed on the undercut metal layer, the passivation layer includes a first passivation part disposed on the first metal part and a second passivation part disposed on the second metal part, the first passivation part and the second passivation part are located on both sides of the via hole, and the cathode layer is continuously disposed along the surface of the second passivation part to the surface of the auxiliary electrode.

2. The display panel according to claim 1, wherein The undercut metal layer includes a sacrificial layer and barrier layers located on both sides of the sacrificial layer; Wherein, the corrosion rate of the sacrificial layer is greater than the corrosion rate of the barrier layer.

3. The display panel according to claim 2, wherein In the first metal part, a bottom cut groove is formed between the sacrificial layer and the barrier layers on both sides, and the bottom cut groove communicates with the via hole.

4. The display panel according to claim 3, wherein In the first metal part, the side of the sacrificial layer away from the via hole is flush with the side of the barrier layer away from the via hole.

5. The display panel according to claim 3, characterized in that, The second metal part is separated from the via hole, and the area of the sacrificial layer of the second metal part is equal to the area of the barrier layer of the second metal part.

6. The display panel according to claim 3, wherein The first passivation part covers the side of the first metal part away from the via hole, the second passivation part covers the entire second metal part, and the cathode layer covers the surface of the second passivation part close to the via hole.

7. The display panel according to claim 3, wherein The display panel further includes a planarization layer disposed on the passivation layer, and the cathode layer is disposed on the planarization layer; Wherein, the orthographic projection of the planarization layer on the undercut metal layer does not coincide with the first metal part and the second metal part.

8. The display panel according to claim 1, wherein The display panel further includes at least one thin film transistor, and the undercut metal layer is disposed on the same layer as the source-drain layer of the thin film transistor.

9. A method for manufacturing a display panel, characterized in that, Comprising: Providing a substrate; Forming an auxiliary electrode on the substrate; Forming an undercut metal layer insulated from the auxiliary electrode on the auxiliary electrode; Using a metal acid solution to perform an undercut etching on the undercut metal layer to form a via hole extending to the surface of the auxiliary electrode; Forming an insulated cathode layer on the undercut metal layer, and making the cathode layer lap with the auxiliary electrode through the via hole; Wherein, the display panel further includes an insulating buffer layer and a passivation layer. The insulating buffer layer is disposed between the auxiliary electrode and the undercut metal layer, and the overlapping hole penetrates through the insulating buffer layer; the passivation layer is disposed on the undercut metal layer. The undercut metal layer includes a first metal part and a second metal part located on both sides of the overlapping hole. At least a part of the first metal part is located within the overlapping hole, and the cathode layer extends through the overlapping hole to be connected to the auxiliary electrode. The passivation layer includes a first passivation part disposed on the first metal part and a second passivation part disposed on the second metal part. The first passivation part and the second passivation part are located on both sides of the overlapping hole, and the cathode layer is continuously disposed along the surface of the second passivation part to the surface of the auxiliary electrode.

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