Method for manufacturing an air bridge and quantum chip

Abstract

The application discloses a manufacturing method of an air bridge and a quantum chip. The manufacturing method comprises the following steps: providing a substrate with a first photoresist layer and a second photoresist layer which are sequentially stacked; forming at least three through holes with a center point sequentially connected to form a closed pattern on the first photoresist layer, and forming an opening exposing all the through holes on the second photoresist layer; forming a first metal structure filling each through hole and a second metal structure covering the first photoresist layer in the opening and connected with all the first metal structures with the same thickness; and removing the first photoresist layer and the second photoresist layer to obtain the air bridge. The first metal structure serves as a pier, and the second metal structure serves as a bridge connecting the piers. Since there are four piers, and the piers are connected by the bridges, the structural strength of the air bridge is enhanced, so that the structural stability of the air bridge is improved, the structure is not easily damaged when the photoresist is removed, and the structure is not easily collapsed after the photoresist is removed.

Description

Technical Field

[0001] This invention relates to the field of quantum chip manufacturing technology, and in particular to a method for manufacturing an air bridge and a quantum chip. Background Technology

[0002] Quantum chips contain numerous coplanar waveguides. Due to limitations in manufacturing processes, the morphology of these waveguides is not perfect and always contains imperfections, such as poor symmetry, uneven edges, and discontinuities. Furthermore, as the number of qubits on a quantum chip increases, the number of coplanar waveguides also increases, making their wiring increasingly complex. To correct these imperfections and facilitate their wiring, existing processes have introduced air bridges to connect the grounding bands on both sides of the coplanar waveguide.

[0003] Current air bridge manufacturing processes, such as Figure 1 As shown, Figure 1 In the diagram, a to e represent the process flow. First, a photoresist P1 for support is formed on the substrate S. Then, an arched photoresist P2 is obtained through heating and reflow. A metal layer M is deposited on the photoresist P2, and excess metal is etched away. Finally, the photoresist P2 is removed by ultrasonic cleaning or other methods, leaving a metal structure that forms an air bridge. However, because the thickness at the edges and corners of this air bridge is very small, its structural stability is poor. Ultrasonic cleaning and other processes can easily cause the air bridge to break, and the lack of support after photoresist removal can easily cause it to collapse. Summary of the Invention

[0004] The purpose of this invention is to provide a method for manufacturing an air bridge and a quantum chip to solve the problem of poor structural stability of air bridges in the prior art and to improve the structural stability of air bridges.

[0005] To solve the above-mentioned technical problems, the present invention provides a method for manufacturing an air bridge, comprising:

[0006] A substrate having a first photoresist layer and a second photoresist layer stacked sequentially is provided;

[0007] At least three vias with their center points connected in sequence to form a closed pattern are formed on the first photoresist layer, and an opening that exposes all of the vias is formed on the second photoresist layer.

[0008] A first metal structure that fills each of the vias and a second metal structure that covers the openings with the same thickness and is connected to all of the first metal structures are formed.

[0009] Remove the first and second photoresist layers to obtain an air bridge.

[0010] Preferably, the step of forming at least three vias with their center points sequentially connected to form a closed pattern on the first photoresist layer, and forming an opening on the second photoresist layer exposing all of the vias, includes:

[0011] An opening pattern is exposed on the second photoresist layer;

[0012] The opening pattern is developed to form an opening that penetrates the second photoresist layer;

[0013] At least three through-hole patterns, whose center points are connected in sequence to form a closed pattern, are exposed on the first photoresist layer inside the opening.

[0014] Each of the via patterns is developed to form a via.

[0015] Preferably, the thickness of the second metal structure does not exceed the thickness of the second photoresist layer.

[0016] Preferably, the opening is annular, and the center line of the projection shape of the opening on the substrate coincides with the projection of the closed pattern on the substrate.

[0017] Preferably, before or after the step of removing the first photoresist layer and the second photoresist layer, the manufacturing method further includes:

[0018] Remove the portion of the second metal structure that is higher than the first metal structure.

[0019] Preferably, the step of removing the portion of the second metal structure that is higher than the first metal structure includes:

[0020] A third photoresist layer is formed covering the first metal structure and the second metal structure;

[0021] An etching pattern is exposed on the third photoresist layer, and the etching pattern is the shape corresponding to the portion of the second metal structure that is higher than the first metal structure.

[0022] The etched pattern is developed to form an etched window;

[0023] The second metal structure within the etching window is etched such that the height of the second metal structure within the etching window is the same as that of the first metal structure.

[0024] Preferably, when the step of removing the portion of the second metal structure that is higher than the first metal structure is performed before the step of removing the first photoresist layer and the second photoresist layer, the step of removing the first photoresist layer and the second photoresist layer further includes: removing the third photoresist layer.

[0025] Preferably, when the step of removing the portion of the second metal structure that is higher than the first metal structure is performed after the steps of removing the first photoresist layer and the second photoresist layer, the step of removing the portion of the second metal structure that is higher than the first metal structure further includes: removing the third photoresist layer.

[0026] Preferably, the first photoresist layer and the second photoresist layer are removed by ultrasonic cleaning.

[0027] Preferably, the number of through holes is four, and both the closed pattern and the through holes are rectangular in shape.

[0028] To address the aforementioned technical problems, the present invention also provides a quantum chip comprising an air bridge obtained by the air bridge manufacturing method according to any one of the preceding claims, wherein the substrate comprises a substrate and a coplanar waveguide formed on the substrate, at least one first metal structure of the air bridge is located on one grounding band of the coplanar waveguide, the remaining first metal structures are located on another grounding band of the coplanar waveguide, the center conductor of the coplanar waveguide passes through the gap between the first metal structures on the two grounding bands, and a second metal structure between the first metal structures on the two grounding bands spans over the center conductor.

[0029] Unlike existing technologies, the air bridge manufacturing method provided by this invention first provides a substrate having a first photoresist layer and a second photoresist layer stacked sequentially. At least three through holes with their center points connected sequentially to form a closed pattern are formed on the first photoresist layer. An opening is formed on the second photoresist layer exposing all the through holes. Then, a first metal structure is filled into each through hole, and a second metal structure is covered on the first photoresist layer inside the opening. Finally, the first and second photoresist layers are removed to obtain the air bridge. The first metal structure serves as the bridge pier, and the second metal structure serves as the bridge deck connecting the piers. Since there are at least three piers, and all piers are connected to each other by a bridge deck, the structural strength is enhanced, thereby improving the structural stability of the air bridge. It is not easy to cause structural damage when removing the photoresist, and it is not easy to collapse after removing the photoresist.

[0030] The quantum chip provided by this invention includes an air bridge obtained according to the aforementioned air bridge manufacturing method, and has the same technical effect, which will not be repeated here. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the manufacturing process of an air bridge in the prior art.

[0032] Figure 2 This is a schematic flowchart illustrating the manufacturing method of an air bridge provided in an embodiment of the present invention.

[0033] Figure 3The first process flow diagram for manufacturing air bridges.

[0034] Figure 4 for Figure 3 Schematic diagram of the cross section along the AA direction in section c.

[0035] Figure 5 for Figure 2 The diagram shows the specific process flow of step S2 in the manufacturing method shown.

[0036] Figure 6 for Figure 2 The diagram shows the specific process flow of step S5 in the manufacturing method shown.

[0037] Figure 7 The second process flow diagram for manufacturing air bridges.

[0038] Figure 8 This is the third process flow diagram for manufacturing air bridges.

[0039] Figure 9 This is a schematic diagram showing the positional relationship between the projection of the opening and the through hole on the substrate.

[0040] Figure 10 This is the fourth process flow diagram for manufacturing air bridges.

[0041] Figure 11 This is a partial structural schematic diagram of the quantum chip provided in an embodiment of the present invention. Detailed Implementation

[0042] The specific embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. The advantages and features of the present invention will become clearer from the following description and claims. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0043] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0044] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0045] Please refer to the reference. Figure 2 and Figure 3 , Figure 3 In this paper, 'a' to 'g' represent the process flow. This invention provides a method for manufacturing an air bridge. The manufacturing method includes the following steps:

[0046] S1: Provides a substrate having a first photoresist layer and a second photoresist layer stacked sequentially.

[0047] The first and second photoresist layers can be formed by coating photoresist. For example, photoresist can be first coated onto a substrate by spin coating. After the photoresist cures, the first photoresist layer is formed. Then, the second photoresist layer is formed on the first photoresist layer in the same way. Figure 3 Figure a shows a schematic diagram of a substrate having a first photoresist layer and a second photoresist layer. The substrate 11 has a first photoresist layer 21 and a second photoresist layer 22 stacked sequentially.

[0048] S2: Form at least three through holes with their center points connected in sequence to form a closed pattern on the first photoresist layer, and form an opening on the second photoresist layer that exposes all the through holes.

[0049] In this embodiment, the center point of the through-hole is the geometric center of its shape. If the through-hole is circular, the center point is the center of the circle; if the through-hole is rectangular, the center point is the intersection of its diagonals. The center points of at least three through-holes constitute the vertices of the closed shape, and connecting any pair of the center points of these three through-holes forms the edges of the closed shape. The number of through-holes can be arbitrarily set; for example, three through-holes form a triangle, four through-holes form a quadrilateral, and six through-holes form a hexagon. In this embodiment, four through-holes are preferred. Furthermore, the closed shape can be a rectangle, rhombus, or other shapes; in this embodiment, a rectangle, especially a square, is preferred. The through-hole can be any shape, such as a rectangle, circle, rounded rectangle, triangle, etc. Again, in this embodiment, a rectangle, especially a square, is preferred. Figure 3 Figure b shows a schematic diagram after vias and openings are formed on the first and second photoresist layers, respectively. Four vias 211 are formed on the first photoresist layer 21. The vias 211 are square, and the center points of the four vias 211 are connected sequentially to form a square. An opening 221 is formed on the second photoresist layer 22, exposing the four vias 211. The opening 221 is also square and coincides with the outer square of the four vias 211.

[0050] S3: A first metal structure that fills each through-hole and a second metal structure that covers the opening and is connected to the entire first metal structure are formed with the same thickness.

[0051] In this design, since the first metal structure fills the through-hole, its cross-sectional shape is identical to that of the through-hole. The second metal structure is connected to the entire first metal structure; therefore, the thickness of the first metal structure must be greater than the depth of the through-hole to ensure connection. The second metal structure covers the first photoresist layer within the opening but avoids all through-holes. The first metal structure serves as the piers of the air bridge, and the second metal structure serves as the bridge deck. Because there are at least three piers, and all piers are connected to each other by bridge decks, the structural strength of the air bridge is enhanced.

[0052] like Figure 3 Figure c shows a schematic diagram after the formation of the first metal structure and the second metal structure. The first metal structure 31 is formed in the through hole 211, and the second metal structure 32 is formed on the first photoresist layer 21 in the opening 221 and is connected to the first metal structure 31. Since the thickness of the first metal structure 31 and the second metal structure 32 are equal, the second metal structure 32 must be higher than the first metal structure 31.

[0053] The first metal structure and metal layer can be formed using deposition processes such as magnetron sputtering and evaporation. During the deposition of the metal material, the metal thickness at each location is the same, so the thickness of the second metal structure is the same as the first metal structure. Since the second metal structure is formed on the first photoresist layer, and the first metal structure is formed within the via, the second metal structure is higher than the first metal structure. Furthermore, because the first and second metal structures are connected, the first metal structure will protrude above the via. For example... Figure 4 As shown, the thickness of the first metal structure 31 inside the through hole 211 is the same as the thickness of the second metal structure 32 on the first photoresist layer 21, both being h.

[0054] S4: Remove the first and second photoresist layers to obtain an air bridge.

[0055] The first and second photoresist layers can be removed using various methods, such as ultrasonic cleaning and reactive ion etching. In this embodiment, ultrasonic cleaning is preferred for removing the first and second photoresist layers. Because the air bridge has at least three piers, its structural stability is very high. Removing the first and second photoresist layers using processes such as ultrasonic cleaning is unlikely to cause structural damage, and the bridge is also less prone to collapse after removal. Figure 3 Figure d shows a schematic diagram after the removal of the first and second photoresist layers. After the first photoresist layer 21 and the second photoresist layer 22 are removed, only the first metal structure 31 and the second metal structure 32 remain on the substrate 11.

[0056] The method for manufacturing an air bridge provided by the present invention, as described above, first provides a substrate having a first photoresist layer and a second photoresist layer stacked sequentially. At least three through-holes are formed on the first photoresist layer, and an opening is formed on the second photoresist layer exposing all the through-holes. Then, a first metal structure is filled into each through-hole, and a second metal structure is covered on the first photoresist layer within the opening. Finally, the first and second photoresist layers are removed to obtain an air bridge. The first metal structure serves as a bridge pier, and the second metal structure serves as a bridge deck connecting the piers. Since there are at least three piers, and all piers are connected to each other by a bridge deck, the structural strength is enhanced, thereby improving the structural stability of the air bridge. When removing the photoresist, structural damage is less likely, and the air bridge is less likely to collapse after the photoresist is removed.

[0057] In some embodiments of this application, the thickness of the second metal structure does not exceed the thickness of the second photoresist layer. Since a metal layer is also formed on the second photoresist layer during the formation of the first and second metal structures using processes such as metal deposition, if this metal layer is connected to the second metal structure, it will affect the integrity of the second metal structure when the second photoresist layer is removed. Since the thickness of the second metal structure does not exceed the thickness of the second photoresist layer, the second metal structure will not be connected to the metal layer on the second photoresist layer. Figure 3 As shown in Figure c, the thickness of the second metal structure 32 is less than the thickness of the second photoresist layer 22.

[0058] In some embodiments of this application, please refer to Figure 5 Step S2 includes the following steps: forming at least three vias with their center points connected sequentially to form a closed pattern on the first photoresist layer; and forming openings on the second photoresist layer that expose all the vias.

[0059] S21: Expose the opening pattern on the second photoresist layer.

[0060] An opening pattern can be exposed on the second photoresist layer using a photomask. The opening pattern matches the shape of the opening.

[0061] S22: Develop the opening pattern to form an opening that penetrates the second photoresist layer.

[0062] In this process, the portion of the second photoresist layer containing the opening pattern can be etched away by developing, thereby forming the opening. By controlling the developing time and speed, only the second photoresist layer within the opening pattern area can be removed without affecting the underlying first photoresist layer.

[0063] S23: Expose at least three through-hole patterns, whose center points are connected in sequence to form a closed pattern, on the first photoresist layer inside the opening.

[0064] Specifically, at least three via patterns, whose center points are sequentially connected to form a closed pattern, can be exposed on the first photoresist layer using a photomask. The via pattern has the same shape as the via.

[0065] S24: Develop each through-hole pattern to form through-holes.

[0066] In this process, the four via patterns on the first photoresist layer can be etched away by developing, thereby forming vias with their center points connected in sequence to form a closed pattern.

[0067] In some embodiments of this application, please refer to the references. Figure 2 and Figure 3 After step S4, the manufacturing method further includes: S5: removing the portion of the second metal structure that is higher than the first metal structure.

[0068] Among them, such as Figure 3 As shown in f, the second metal structure 32 between two adjacent first metal structures 31 is higher than the first metal structure 31. By removing the higher portion of the second metal structure, a flat bridge surface can be obtained, ultimately resulting in an air bridge with a flat bridge surface.

[0069] For further details, please refer to... Figure 6 The step of removing the portion of the second metal structure that is higher than the first metal structure, i.e., step S5, includes:

[0070] S51: Form a third photoresist layer covering the first metal structure and the second metal structure.

[0071] S52: An etching pattern is exposed on the third photoresist layer, the etching pattern being the shape corresponding to the portion of the second metal structure that is higher than the first metal structure.

[0072] The etched pattern can be exposed using a photomask.

[0073] S53: Develop the etched pattern to form an etched window.

[0074] In this process, the portion of the third photoresist layer containing the etched pattern is etched away by developing and etching, thereby forming an etched window. For example... Figure 3 Figure e shows a schematic diagram after the etching window is formed. An etching window 231 is formed on the third photoresist layer 23, and the second metal structure 32 exposed by the etching window 231 is higher than the first metal structure 31.

[0075] S54: Etch the second metal structure within the etching window so that the height of the second metal structure within the etching window is the same as that of the first metal structure.

[0076] By controlling etching conditions, such as etching time and etching speed, the portion of the second metal structure that is higher than the first metal structure can be etched away precisely, making the two structures the same height.

[0077] After etching the second metal structure, the third photoresist layer needs to be removed to expose the air bridges. The step of removing the portion of the second metal structure that protrudes above the first metal structure also includes removing the third photoresist layer. For example... Figure 3 Figure f shows a schematic diagram after the third photoresist layer is removed. After the third photoresist layer 23 is removed, only the first metal structure 31 and the second metal structure 32 remain on the substrate 11, and the two have the same height, resulting in a flat air bridge.

[0078] As an alternative, step S5 can also be performed before step S4; please refer to the reference. Figure 7 , Figure 7 In the diagram, a to e represent another set of technological processes, which are related to... Figure 7 a to c in Figure 3 The numbers a through c are the same. For example... Figure 7 Figure d shows a schematic diagram after the etched window is formed. The first photoresist layer 21, the second photoresist layer 22, and the third photoresist layer 23 are stacked sequentially. The etched window 231 on the third photoresist layer 23 exposes the portion of the second metal structure 32 that is higher than the first metal structure 31. After the second metal structure is etched, the third photoresist layer needs to be removed to expose the air bridge. Figure 7 Figure e shows a schematic diagram after the removal of the third photoresist layer. The third photoresist layer 23 is removed together with the first photoresist layer 21 and the second photoresist layer 22, leaving only the first metal structure 31 and the second metal structure 32 on the substrate 11, and the two have the same height, resulting in a flat air bridge.

[0079] In some embodiments of this application, the opening is annular, and the center line of the projection shape of the opening onto the substrate coincides with the projection of the closed pattern onto the substrate. For example, when the closed pattern is circular, the opening is annular; when the closed pattern is rectangular, the opening is annular, composed of two concentric rectangles. Because the area of ​​the second metal structure in the aforementioned embodiments is relatively large, the first photoresist layer beneath it is obscured and difficult to etch. By making the opening annular, more of the first photoresist layer can be exposed after the second metal structure is formed. Figure 8 As shown, Figure 8 The process flow represented by a to f in the middle can be replaced Figure 3 The process flow represented by a to f in the figure. Figure 8 In step b, the opening 221 formed on the second photoresist layer 22 is annular. For example... Figure 9The diagram shows the positional relationship between the projections of the openings and through holes on the substrate. The projections of the four through holes 211 are squares, and the inner and outer contours of the projections of the openings 221 are also squares. The center line of the projection of the opening 221 (the square dashed box in the figure) is also a square, and the center line of the projection of the opening 221 coincides with the preset quadrilateral. Figure 8 In c, since the opening 221 is annular, the second metal structure 32 formed is a hollow structure, and the hollow region is the area surrounded by the opening 221. Figure 8 d and Figure 8 The air bridge obtained in f has a hollow bridge deck.

[0080] like Figure 10 As shown, Figure 10 The process flow represented by a to e in the middle can be replaced Figure 7 The process flow is represented by a to e in the diagram. Figure 10 In b, the opening 221 formed on the second photoresist layer 22 is annular. Figure 10 In c, since the opening 221 is annular, the second metal structure 32 formed is a hollow structure, and the hollow region is the area surrounded by the opening 221. Figure 10 The air bridge obtained in e has a hollow bridge deck.

[0081] Please refer to Figure 11 The present invention also provides a quantum chip, the quantum chip comprising an air bridge obtained by the air bridge manufacturing method according to the foregoing embodiments. Figure 10 Taking the obtained air bridge as an example, the substrate 11 includes a substrate 110 and a coplanar waveguide 120 formed on the substrate 110. At least one first metal structure 31 of the air bridge is located on one grounding strip 121 of the coplanar waveguide 120, and the remaining first metal structures 31 are located on another grounding strip 121 of the coplanar waveguide 120. The center conductor 122 of the coplanar waveguide 120 passes through the gap between the first metal structures 31 on the two grounding strips 121, and the second metal structure 32 between the first metal structures 31 on the two grounding strips 121 spans over the center conductor 122.

[0082] As a preferred embodiment, two adjacent first metal structures 31 of the air bridge are located on one grounding strip 121, and the other two first metal structures 31 are located on another grounding strip 121. Since the air bridge has four piers, there is a gap between any two adjacent piers. There is no need to specifically set the direction of the air bridge. It is only necessary to ensure that the center conductor of the coplanar waveguide passes through the gap between any two adjacent piers. For coplanar waveguides with two mutually perpendicular wiring directions, the air bridge manufacturing method of this embodiment is more applicable than the traditional air bridge manufacturing method, especially when the quadrilateral is preset to be a square. This is because the coplanar waveguides in both wiring directions can be adapted to the air bridge of this embodiment. It is only necessary to ensure that the central axis of the closed shape is parallel (preferably overlapping) with the center line of the coplanar waveguide.

[0083] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," or "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0084] The above are merely preferred embodiments of the present invention and do not constitute any limitation on the present invention. Any equivalent substitutions or modifications made by those skilled in the art to the technical solutions and content disclosed in the present invention without departing from the scope of the present invention shall be deemed to have remained within the protection scope of the present invention.

Claims

1. A method for manufacturing an air bridge, characterized in that, include: A substrate having a first photoresist layer and a second photoresist layer stacked sequentially from bottom to top is provided; At least three vias with their center points connected in sequence to form a closed pattern are formed on the first photoresist layer, and a single opening is formed on the second photoresist layer that exposes all of the vias. A first metal structure with the same thickness is formed to fill each of the vias and a second metal structure that covers the opening, is connected to all of the first metal structures and has the same thickness as the first metal structures; Remove the first and second photoresist layers to obtain an air bridge.

2. The manufacturing method according to claim 1, characterized in that, The step of forming at least three vias with their center points connected sequentially to form a closed pattern on the first photoresist layer, and forming a single opening on the second photoresist layer that exposes all of the vias, includes: An opening pattern is exposed on the second photoresist layer; The opening pattern is developed to form an opening that penetrates the second photoresist layer; At least three through-hole patterns, whose center points are connected in sequence to form a closed pattern, are exposed on the first photoresist layer inside the opening. Each of the via patterns is developed to form a via.

3. The manufacturing method according to claim 1, characterized in that, The thickness of the second metal structure does not exceed the thickness of the second photoresist layer.

4. The manufacturing method according to claim 1, characterized in that, The opening is annular, and the center line of the projection shape of the opening on the substrate coincides with the projection of the closed shape on the substrate.

5. The manufacturing method according to any one of claims 1 to 4, characterized in that, Before or after the step of removing the first photoresist layer and the second photoresist layer, the manufacturing method further includes: Remove the portion of the second metal structure that is higher than the first metal structure, so that the second metal structure avoids all through holes.

6. The manufacturing method according to claim 5, characterized in that, The step of removing the portion of the second metal structure that is higher than the first metal structure includes: A third photoresist layer is formed covering the first metal structure and the second metal structure; An etching pattern is exposed on the third photoresist layer, and the etching pattern is the shape corresponding to the portion of the second metal structure that is higher than the first metal structure. The etched pattern is developed to form an etched window; The second metal structure within the etching window is etched such that the height of the second metal structure within the etching window is the same as that of the first metal structure.

7. The manufacturing method according to claim 6, characterized in that, If the step of removing the portion of the second metal structure that is higher than the first metal structure is performed before the step of removing the first photoresist layer and the second photoresist layer, the step of removing the first photoresist layer and the second photoresist layer further includes removing the third photoresist layer.

8. The manufacturing method according to claim 6, characterized in that, When the step of removing the portion of the second metal structure that is higher than the first metal structure is performed after the steps of removing the first photoresist layer and the second photoresist layer, the step of removing the portion of the second metal structure that is higher than the first metal structure further includes: removing the third photoresist layer.

9. The manufacturing method according to claim 1, characterized in that, The first and second photoresist layers were removed by ultrasonic cleaning.

10. The manufacturing method according to claim 1, characterized in that, The number of through holes is four, and the shape of both the closed pattern and the through holes is rectangular.

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