A display panel and a manufacturing method thereof

Abstract

The present invention relates to the field of display technology, and discloses a display panel and a manufacturing method thereof, wherein the display panel comprises a substrate, the substrate having a display area and a binding area located outside the display area; wherein the binding area comprises: a first metal layer disposed on the substrate; an insulating layer disposed on the first metal layer; a second metal layer disposed on the insulating layer, the insulating layer being formed with an opening so that the second metal layer sinks to form a groove portion, the second metal layer overlaps the first metal layer through the groove portion; and a protective layer disposed on the second metal layer, the protective layer at least covering the slope of the groove portion. The display panel and the manufacturing method thereof improve the dark spot problem of an OLED display panel.

Description

Technical Field

[0001] The present invention relates to the field of display technology, and in particular to a display panel and a manufacturing method thereof. Background Art

[0002] In the prior art, display panels are increasingly widely used, among which OLED (Organic Light-Emitting Diode) display panels, as a type of display panel, are particularly widely used.

[0003] By studying the dark spots of OLED display panels, it was found that one of the causes of dark spots is the presence of certain silver particles on the pixel anode. These silver particles cause a short circuit between the anode and cathode of the OLED device, causing dark spots. Summary of the invention

[0004] The present invention provides a display panel and a manufacturing method thereof, which are used to improve the dark spot problem of an OLED display panel.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A display panel comprises a substrate, wherein the substrate has a display area and a binding area located outside the display area; wherein the binding area has:

[0007] A first metal layer disposed on the substrate;

[0008] An insulating layer disposed on the first metal layer;

[0009] A second metal layer is disposed on the insulating layer, the insulating layer is formed with an opening so that the second metal layer sinks to form a groove portion, and the second metal layer overlaps with the first metal layer through the groove portion;

[0010] A protection layer is disposed on the second metal layer, and the protection layer at least covers the slope surface of the groove portion.

[0011] The display panel provided by the present invention is provided with a protective layer on the second metal layer, which at least covers the slope of the groove portion of the second metal layer. The protective layer can prevent the top layer Ti from being missing due to PVX over-etching during the PVX etching process on the slope of the groove portion of the second metal layer, and avoid Al exposure on the slope of the groove portion of the second metal layer, and can also protect the second metal layer during the anode wet etching process. Therefore, it is possible to prevent Ag particles from precipitating from the slope of the groove portion of the second metal layer, reduce the Ag particles migrating to the pixel anode surface from the root, and reduce the possibility of short circuit between the anode and cathode of the OLED device, thereby improving the dark spot problem of the OLED display panel and improving the yield of the OLED display panel.

[0012] Optionally, the protective layer covers the slope surface of the groove portion and a portion of the bottom surface connected to the slope surface.

[0013] Optionally, the second metal layer includes a connection area for electrical connection with the outside, and the protective layer covers a region of the second metal layer except the connection area.

[0014] Optionally, a passivation layer is included on a side of the second metal layer facing away from the first metal layer, and a portion of the passivation layer forms the protective layer.

[0015] Optionally, the passivation layer is in the same layer as the passivation layer of the display area.

[0016] Optionally, a planar layer is included on a side of the second metal layer facing away from the first metal layer, and a portion of the planar layer forms the protective layer.

[0017] Optionally, the planar layer is in the same layer as the planar layer of the display area.

[0018] Optionally, an anode metal layer is included which is located on a side of the second metal layer away from the first metal layer, and a portion of the anode metal layer forms the protective layer.

[0019] Optionally, the anode metal layer is in the same layer as the anode metal layer in the display area.

[0020] Optionally, a support layer is provided between the first metal layer and the second metal layer, and the support layer includes two support parts, the two support parts correspond one-to-one to the two corner parts at the top of the groove part, and the slope angle of each support part corresponding to the bottom foot of the groove part is less than 30°.

[0021] The present invention further provides a method for manufacturing a display panel, wherein the display panel comprises a substrate, the substrate having a display area and a binding area located outside the display area, and the manufacturing method comprises:

[0022] forming a first metal layer in a bonding region on the substrate;

[0023] Disposing an insulating layer on the first metal layer, and disposing via holes on the insulating layer through a patterning process;

[0024] Disposing a second metal layer on the insulating layer, wherein the second metal layer is sunken at the via hole to form a groove portion, and is overlapped with the first metal layer through the groove portion;

[0025] A protective layer is disposed on the second metal layer, and the protective layer at least covers the slope surface of the groove portion.

[0026] In the display panel manufactured by the manufacturing method of the display panel provided by the present invention, a protective layer covering at least the slope of the groove portion of the second metal layer is arranged on the second metal layer. The protective layer can prevent the top layer Ti from being missing due to PVX over-etching on the slope of the groove portion of the second metal layer during the PVX etching process, and avoid Al exposure on the slope of the groove portion of the second metal layer, and can also protect the second metal layer during the anode wet etching process. Therefore, it is possible to prevent Ag particles from precipitating from the slope of the groove portion of the second metal layer, reduce the Ag particles migrating to the pixel anode surface from the root, and reduce the possibility of short circuit between the anode and cathode of the OLED device, thereby improving the dark spot problem of the OLED display panel and improving the yield of the display panel.

[0027] Optionally, the step of providing a protective layer on the second metal layer, wherein the protective layer at least covers the slope surface of the groove portion, specifically includes:

[0028] A passivation layer is disposed on the second metal layer, and the passivation layer is formed into the protection layer through a patterning process.

[0029] Optionally, the step of providing a protective layer on the second metal layer, wherein the protective layer at least covers the slope surface of the groove portion, specifically includes:

[0030] A planar layer is disposed on the second metal layer, and the planar layer is formed into the protective layer through a patterning process.

[0031] Optionally, the step of providing a protective layer on the second metal layer, wherein the protective layer at least covers the slope surface of the groove portion, specifically includes:

[0032] An anode metal layer is disposed on the second metal layer, and the anode metal layer is formed into the protective layer through a patterning process.

[0033] Optionally, before providing the second metal layer on the insulating layer, the method comprises:

[0034] A support layer is provided between the first metal layer and the second metal layer, wherein the support layer includes two support portions, the two support portions correspond one-to-one to the two corner portions at the top of the groove portion, and the slope angle of each support portion corresponding to the bottom foot of the groove portion is less than 30°. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A schematic diagram of the structure of a display panel provided by the prior art;

[0036] Figure 2 for Figure 1 In the display panel shown, the Al at the slope and bottom of the second metal layer is corroded to form voids in the FIB image;

[0037] Figure 3 A schematic diagram of the structure of a display panel provided by an embodiment of the present invention;

[0038] Figure 4 A schematic diagram of the structure of a display panel provided by an embodiment of the present invention;

[0039] Figure 5 A schematic diagram of the structure of a display panel provided by an embodiment of the present invention;

[0040] Figure 6 A schematic diagram of the structure of a display panel provided by an embodiment of the present invention;

[0041] Figure 7 In the display panel provided in this embodiment, a FIB image of the slope and the bottom of the slope of the second metal layer;

[0042] Figure 8 A schematic diagram of the structure of a display panel provided by an embodiment of the present invention;

[0043] Figure 9A-9I A step diagram of a method for manufacturing a display panel pair provided by an embodiment of the present invention;

[0044] Fig.10 and Fig.11 They are structural schematic diagrams of a method for manufacturing a display panel pair provided by an embodiment of the present invention after one step.

[0045] Icon: 1-substrate; 2-first metal layer; 3-insulating layer; 4-second metal layer; 401-groove portion; 5-passivation layer; 6-flat layer; 7-anode metal layer; 8-support portion; 9-buffer layer; 10-first gate insulating layer; 11-second gate insulating layer; 12-interlayer dielectric layer; 13-touch insulating layer; 14-touch electrode layer. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] Further research found that the source of the silver particles is the gold fingers in the bonding area. Specifically, Figure 1As shown, the binding area includes a first metal layer 2 disposed on a substrate 1, an insulating layer 3 disposed on the first metal layer 2, and a second metal layer 4 disposed on the insulating layer 3, and the second metal layer 4 is overlapped with the first metal layer 2 through a via hole on the insulating layer 3. Among them, the second metal layer 4 is composed of three layers of Ti / AL / Ti metal stacking, and the complete top layer Ti can protect the active AL film layer thereunder.

[0048] FIB microscopic cross-sectional structural analysis found that: the height difference between the two parts of the second metal layer 4 above and below the via hole in the insulating layer 3 is relatively large (about 8000 angstroms), resulting in a larger slope angle of the second metal layer 4, which in turn causes the top layer Ti of the second metal layer 4 to be thinner at the bottom and slope (for example: the top layer Ti thickness in the flat area is 500 angstroms, while the top layer Ti thickness at the slope and bottom is about 300 angstroms, or even thinner). In the PVX (passivation layer) etching process of the display panel, the superimposed PVX over-etching causes the top layer Ti at the bottom and slope of the binding area to be missing, resulting in the exposure of Al in the second metal layer 4; in the anode wet etching process, the exposed Al in the binding area replaces the Ag ions in the wet etching solution, precipitating Ag silver particles, which randomly migrate to the pixel anode surface for retention, and the anode and cathode of the OLED device are short-circuited after the EV (evaporation) process, resulting in dark spots. Figure 2 As shown in A in the middle, it is a FIB image of Al being corroded to form voids at the slope and bottom of the second metal layer 4.

[0049] Based on this, this embodiment provides a display panel to improve the above problem.

[0050] A display panel provided in this embodiment includes a substrate 1, wherein the substrate 1 has a display area and a binding area located outside the display area; Figure 3-Figure 6 As shown, wherein the binding area has:

[0051] A first metal layer 2 disposed on the substrate 1;

[0052] An insulating layer 3 is disposed on the first metal layer 2;

[0053] A second metal layer 4 is disposed on the insulating layer 3, wherein the insulating layer 3 is formed with an opening so that the second metal layer 4 sinks to form a groove portion 401, and the second metal layer 4 overlaps the first metal layer 2 through the groove portion 401;

[0054] The protection layer is disposed on the second metal layer 4 , and the protection layer at least covers the slope surface of the groove portion 401 .

[0055] The display panel provided in this embodiment is provided with a protective layer on the second metal layer 4, which at least covers the slope surface of the groove portion 401 of the second metal layer 4. The protective layer can prevent the top layer Ti from being missing due to PVX over-etching on the slope surface of the groove portion 401 of the second metal layer 4 during the PVX etching process, and avoid Al exposure on the slope surface of the groove portion 401 of the second metal layer 4, and can also protect the second metal layer 4 during the anode wet etching process. Therefore, it is possible to prevent Ag particles from precipitating from the slope surface of the groove portion 401 of the second metal layer 4, reduce the Ag particles migrating to the pixel anode surface from the root, and reduce the possibility of short circuit between the anode and the cathode of the OLED device, thereby improving the dark spot problem of the OLED display panel and improving the yield of the OLED display panel.

[0056] When setting the above protection layer, Figure 3 As shown, in an optional implementation, the protective layer covers the slope surface of the groove portion 401 and a portion of the bottom surface connected to the slope surface.

[0057] The second metal layer 4 is thinner on the slope of the groove 401 and the part where the slope is connected to the bottom surface. The protective layer covers the slope of the groove 401 and the part of the bottom surface connected to the slope, which can better protect the weak parts of the second metal layer 4, and is beneficial to further reduce the Ag particles migrating to the pixel anode surface from the source, thereby reducing the possibility of short circuit between the anode and cathode of the OLED device.

[0058] The second metal layer 4 includes a connection area for electrical connection with the outside world. In order to provide more comprehensive protection for the second metal layer 4, the Ag particles migrating to the surface of the pixel anode are minimized (or even avoided) to reduce the possibility of short circuit between the anode and cathode of the OLED device. Figure 4 As shown, in another optional implementation, the protection layer covers the area of ​​the second metal layer 4 except the connection area.

[0059] The display panel includes a passivation layer (PVX) 5 located on a side of the second metal layer 4 facing away from the first metal layer 2. In an optional implementation, a portion of the passivation layer 5 forms a protective layer.

[0060] like Figure 7 As shown at B in the middle, the verification test shows that after the passivation layer 5 covers the bottom of the groove slope, no corrosion of the second metal layer 4 occurs.

[0061] In order to simplify the structure of the display panel, in a specific implementation, the passivation layer 5 is in the same layer as the passivation layer of the display area.

[0062] The display panel includes a planar layer 6 located on a side of the second metal layer 4 facing away from the first metal layer 2. In an alternative embodiment, a portion of the planar layer (PLN layer) 6 forms the above-mentioned protective layer.

[0063] The protective layer is formed by an organic PLN layer. In the wet etching process, the PLN layer can isolate the etching solution and the groove portion 401 of the second metal layer 4, thereby preventing the Al from being corroded and silver particles from being precipitated to cause dark spots.

[0064] In order to simplify the structure of the display panel, in a specific implementation, the planar layer 6 is in the same layer as the planar layer of the display area.

[0065] The display panel comprises an anode metal layer 7 located on a side of the second metal layer 4 facing away from the first metal layer 2. In an alternative manner, a portion of the anode metal layer 7 forms the above-mentioned protective layer.

[0066] The anode metal layer 7 can play a role in isolating the etching solution and the groove portion 401 of the second metal layer 4, thereby preventing the Al from being corroded and precipitating silver particles to cause dark spots.

[0067] Optionally, the anode metal layer 7 may be an ITO / Ag / ITO metal film layer.

[0068] In order to simplify the structure of the display panel, in a specific implementation, the anode metal layer 7 is in the same layer as the anode metal layer in the display area.

[0069] In an optional implementation, Figure 8 As shown, a support layer is provided between the first metal layer 2 and the second metal layer 4, and the support layer includes two support portions 8, and the two support portions 8 correspond one-to-one to the two corner portions at the top of the groove portion 401, and the slope angle of each support portion 8 corresponding to the bottom foot of the groove portion 401 is less than 30°.

[0070] As analyzed above, the second metal layer 4 has a large slope angle, which is the fundamental reason why the top layer Ti of the second metal layer 4 is thin at the bottom and slope, and thus causes dark spots. A support portion 8 corresponding to the two corners at the top of the groove portion 401 is provided between the first metal layer 2 and the second metal layer 4, and the slope angle of the support portion 8 corresponding to the bottom of the groove portion 401 is less than 30°, so that the thickness of the top layer Ti at the slope surface of the groove portion 401 and the bottom of the slope connected to the slope surface can be maintained within a set range, ensuring that the top layer Ti will not be completely etched away during PVX etching, thereby avoiding the occurrence of Al exposure, and then the wet etching liquid will not react with Al to precipitate Ag particles during the anode wet etching process, causing dark spots.

[0071] Specifically, the support layer may be an OC (Over Coat, a transparent photoresist that protects the corresponding film layer and reduces the height difference between layers) layer.

[0072] Verification tests show that the dark spot incidence rate of the display panel in the prior art is 20.3%. The dark spot incidence rate of the display panel provided by this embodiment is lower than that of the display panel in the prior art. For example, under corresponding process conditions, the dark spot incidence rate of the display panel provided by this embodiment can be 0.3%, 0.2%, or even 0.1%.

[0073] This embodiment further provides a method for manufacturing a display panel, wherein the display panel includes a substrate 1, the substrate 1 has a display area and a binding area outside the display area, and the manufacturing method includes:

[0074] forming a first metal layer 2 in a bonding area on the substrate 1;

[0075] An insulating layer 3 is provided on the first metal layer 2, and via holes are provided on the insulating layer 3 by a patterning process;

[0076] A second metal layer 4 is disposed on the insulating layer 3. The second metal layer 4 is sunken at the via hole to form a groove portion 401, and is overlapped with the first metal layer 2 through the groove portion 401;

[0077] A protection layer is disposed on the second metal layer 4 , and the protection layer at least covers the slope surface of the groove portion 401 .

[0078] In the display panel manufactured by the manufacturing method of the display panel provided by the present embodiment, a protective layer is provided on the second metal layer 4, which at least covers the slope surface of the groove portion 401 of the second metal layer 4. The protective layer can prevent the top layer Ti from being missing due to PVX over-etching on the slope surface of the groove portion 401 of the second metal layer 4 during the PVX etching process, and avoid Al exposure on the slope surface of the groove portion 401 of the second metal layer 4, and can also protect the second metal layer 4 during the anode wet etching process. Therefore, it is possible to prevent Ag particles from precipitating from the slope surface of the groove portion 401 of the second metal layer 4, reduce the Ag particles migrating to the pixel anode surface from the root, and reduce the possibility of short circuit between the anode and cathode of the OLED device, thereby improving the dark spot problem of the OLED display panel and improving the yield of the display panel.

[0079] In an optional implementation, a protective layer is provided on the second metal layer 4, and the protective layer at least covers the slope surface of the groove portion 401, specifically including:

[0080] A passivation layer 5 is disposed on the second metal layer 4 and is formed into a protective layer through a patterning process.

[0081] In another optional implementation, a protective layer is provided on the second metal layer 4, and the protective layer at least covers the slope surface of the groove portion 401, specifically including:

[0082] A planarization layer 6 is disposed on the second metal layer 4 and is formed into a protection layer through a patterning process.

[0083] In another optional implementation, a protective layer is provided on the second metal layer 4, and the protective layer at least covers the slope surface of the groove portion 401, specifically including:

[0084] An anode metal layer 7 is disposed on the second metal layer 4, and the anode metal layer 7 is formed into a protective layer through a patterning process.

[0085] In an optional implementation, before providing the second metal layer 4 on the insulating layer 3, the method includes:

[0086] A support layer is provided between the first metal layer 2 and the second metal layer 4, wherein the support layer includes two support portions 8, the two support portions 8 correspond one-to-one to the two corner portions at the top of the groove portion 401, and the slope angle of each support portion 8 corresponding to the bottom foot of the groove portion 401 is less than 30°.

[0087] Combine the following Figure 9A-9I A method for manufacturing a display panel provided in this embodiment is specifically described. The method for manufacturing a display panel includes:

[0088] Step S1, preparing a buffer layer 9 (buffer) in the binding area on the substrate 1, wherein the buffer layer 9 can be prepared in the same layer as the buffer layer 9 in the display area;

[0089] Step S2, preparing a first gate insulating layer (GI1) 10 on the buffer layer 9, wherein the first gate insulating layer 10 can be prepared in the same layer as the first gate insulating layer 10 in the display area;

[0090] Step S3, preparing a first metal layer 2 on the first gate insulating layer 10, wherein the first metal layer 2 can be prepared on the same layer as the gate lines of the display area.

[0091] Step S4, disposing a second gate insulating layer (GI2) 11 on the first metal layer 2, wherein the second gate insulating layer 11 can be prepared in the same layer as the second gate insulating layer 11 of the display area;

[0092] Step S5, preparing an interlayer dielectric layer (ILD) 12 on the second gate insulating layer 11, and setting vias on the second gate insulating layer 11 and the interlayer dielectric layer 12 through a patterning process to expose the connection area of ​​the first metal layer 2;

[0093] The interlayer dielectric layer 12 can be prepared at the same layer as the interlayer dielectric layer 12 of the display area.

[0094] Step S6, preparing a second metal layer 4 on the interlayer dielectric layer 12, the second metal layer 4 is sunken at the via holes on the second gate insulating layer 11 and the interlayer dielectric layer 12 to form a groove portion 401, and is overlapped with the first metal layer 2 through the groove portion 401;

[0095] The second metal layer 4 can be prepared in the same layer as the source and drain electrodes of the display area.

[0096] Step S7, preparing a passivation layer 5 (PVX) on the second metal layer 4, wherein the passivation layer 5 can be prepared on the same layer as the passivation layer of the display area.

[0097] Step S8, preparing a planar layer 6 (PLN) on the passivation layer 5, wherein the planar layer 6 can be prepared on the same layer as the planar layer of the display area.

[0098] Step S9 , preparing a touch insulating layer (TLD) 13 on the flat layer 6 , wherein the touch insulating layer 13 can be prepared on the same layer as the touch insulating layer of the display area.

[0099] Step S10 , preparing a touch electrode layer (TMB) 14 on the touch insulating layer 13 , wherein the touch electrode layer 14 can be prepared on the same layer as the touch electrode layer of the display area.

[0100] In an optional technical solution, in step S7, a passivation layer 5 is prepared on the second metal layer 4, specifically including: the passivation layer 5 extends to the groove portion 401 of the second metal layer 4, and a part of the passivation layer 5 forms the aforementioned protective layer.

[0101] In another optional technical solution, Fig.10 As shown, in step S8, a flat layer 6 is prepared on the passivation layer 5, specifically including: the flat layer 6 extends to the groove portion 401 of the second metal layer 4, and a part of the flat layer 6 forms the aforementioned protective layer.

[0102] In an optional technical solution, Fig.11 As shown, before step S9, it includes: preparing an anode metal layer 7 on the flat layer 6, wherein the anode metal layer 7 can be in the same layer as the anode metal layer of the display area of ​​the display panel.

[0103] In a specific implementation, the anode metal layer 7 is prepared on the flat layer 6, including: the anode metal layer 7 extends to the groove portion 401 of the second metal layer 4, and a part of the anode metal layer 7 forms the aforementioned protective layer.

[0104] In an optional technical solution, before the above-mentioned step S6, it includes: preparing a support layer on the interlayer dielectric layer 12, wherein the support layer includes two support parts 8, the two support parts 8 correspond one-to-one to the two corner parts at the top of the groove part 401, and the slope angle of each support part 8 corresponding to the bottom foot of the groove part 401 is less than 30°.

[0105] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A display panel, characterized in that: The invention comprises a substrate, wherein the substrate has a display area and a binding area located outside the display area; wherein the binding area has: A first metal layer disposed on the substrate; An insulating layer disposed on the first metal layer; A second metal layer is disposed on the insulating layer, the insulating layer is formed with an opening so that the second metal layer sinks to form a groove portion, and the second metal layer overlaps with the first metal layer through the groove portion; A protective layer disposed on the second metal layer, the protective layer covers the slope surface of the groove portion, and the protective layer at least partially exposes the bottom surface of the groove portion; The protective layer covers the slope surface of the groove portion and a portion of the bottom surface connected to the slope surface.

2. The display panel according to claim 1, characterized in that: The second metal layer includes a connection area for electrical connection with the outside, and the protection layer covers the area of ​​the second metal layer except the connection area.

3. The display panel according to claim 1, characterized in that: A passivation layer is included and is located on a side of the second metal layer facing away from the first metal layer, and a portion of the passivation layer forms the protection layer.

4. The display panel according to claim 3, characterized in that: The passivation layer is in the same layer as the passivation layer of the display area.

5. The display panel according to claim 1, characterized in that: The invention comprises a flat layer located on a side of the second metal layer facing away from the first metal layer, and a part of the flat layer forms the protection layer.

6. The display panel according to claim 5, characterized in that: The planar layer is in the same layer as the planar layer of the display area.

7. The display panel according to claim 1, characterized in that: An anode metal layer is included which is located on a side of the second metal layer away from the first metal layer, and a part of the anode metal layer forms the protection layer.

8. The display panel according to claim 7, characterized in that: The anode metal layer is in the same layer as the anode metal layer in the display area.

9. A method for manufacturing a display panel, wherein: The display panel includes a substrate, wherein the substrate has a display area and a binding area located outside the display area, and is characterized by comprising: forming a first metal layer in a bonding region on the substrate; Disposing an insulating layer on the first metal layer, and disposing via holes on the insulating layer through a patterning process; Disposing a second metal layer on the insulating layer, wherein the second metal layer is sunken at the via hole to form a groove portion, and is overlapped with the first metal layer through the groove portion; A protective layer is disposed on the second metal layer, the protective layer covers the slope of the groove portion and at least partially exposes the bottom of the groove portion; the protective layer covers the slope of the groove portion and a portion of the bottom connected to the slope.

10. The manufacturing method according to claim 9, characterized in that: The step of providing a protective layer on the second metal layer, wherein the protective layer at least covers the slope of the groove portion, specifically includes: A passivation layer is disposed on the second metal layer, and the passivation layer is formed into the protection layer through a patterning process.

11. The manufacturing method according to claim 9, characterized in that: The step of providing a protective layer on the second metal layer, wherein the protective layer at least covers the slope of the groove portion, specifically includes: A planar layer is disposed on the second metal layer, and the planar layer is formed into the protective layer through a patterning process.

12. The manufacturing method according to claim 9, characterized in that: The step of providing a protective layer on the second metal layer, wherein the protective layer at least covers the slope of the groove portion, specifically includes: An anode metal layer is disposed on the second metal layer, and the anode metal layer is formed into the protective layer through a patterning process.

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