Josephson junction and method of manufacturing the same

Abstract

The application discloses a Josephson junction and a manufacturing method thereof. The manufacturing method comprises the following steps: forming a mask on a substrate, the mask having a window exposing the substrate, a first channel and a second channel, the first channel and the second channel extending along a first direction and a second direction perpendicular to each other respectively, and both of the first channel and the second channel communicating with the window; performing inclined film plating along the first direction to form a first superconducting plate in the window and a first superconducting wire connecting the first superconducting plate in the first channel; forming a barrier layer on the surface of the first superconducting plate; and performing inclined film plating along the second direction to form a second superconducting plate at least partially located on the barrier layer in the window and a second superconducting wire connecting the second superconducting plate in the second channel. The application can eliminate the restriction of the channel width on the resistance of the Josephson junction, and is particularly suitable for manufacturing the Josephson junction with small resistance.

Description

Technical Field

[0001] This invention relates to the field of semiconductor process technology, and in particular to a Josephson junction and its manufacturing method. Background Technology

[0002] In superconducting quantum chips, a Josephson junction is composed of two superconducting layers sandwiched by a very thin barrier layer. Currently, Josephson junctions are mainly formed by the overlapping of two superconducting wires, with the barrier layer formed on the surface of the bottom superconducting wire through oxidation. The area of ​​the Josephson junction is the overlapping area of ​​the two superconducting wires; therefore, with a constant barrier layer thickness, the resistance of the Josephson junction is inversely proportional to the linewidth of the superconducting wires.

[0003] However, the inventors of this application, through long-term research, discovered that two superconducting wires are typically obtained by tilting the coating through two mutually perpendicular trenches on the photoresist. The width of the trenches can be made very small, as long as the resolution of the photolithography machine is sufficient, but it cannot be made very large. This is because the tilting coating process requires that if the width of the trenches exceeds a certain threshold, a short circuit will form outside the overlapping area during coating, causing coating failure. Figure 1 As shown, two superconducting wires overlap perpendicularly. However, due to the excessively wide channel, when plating each superconducting wire, an extra portion was plated at the location of the other superconducting wire, causing the two superconducting wires to short-circuit in the excess plating area (within the dotted circle in the figure). Therefore, the fabrication of a low-resistance Josephson junction is limited by the channel width. Summary of the Invention

[0004] The purpose of this invention is to provide a Josephson junction and its manufacturing method to solve the problem of channel width limitation when manufacturing Josephson junctions with low resistance in the prior art, and to eliminate the limitation of channel width on the resistance of Josephson junctions.

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

[0006] A mask is formed on a substrate, the mask having a window exposing the substrate, a first channel and a second channel, the first channel and the second channel extending along a first direction and a second direction that are perpendicular to each other, and both communicating with the window;

[0007] An inclined coating is applied along the first direction to form a first superconducting plate within the window and a first superconducting wire connecting the first superconducting plate within the first channel.

[0008] A barrier layer is formed on the surface of the first superconducting plate;

[0009] An inclined coating is performed along the second direction to form a second superconducting plate that is at least partially located on the barrier layer within the window, and a second superconducting wire that connects the second superconducting plate is formed within the second channel.

[0010] Preferably, the mask includes a first photoresist layer and a second photoresist layer formed on the first photoresist layer, and the window extends through the first photoresist layer and the second photoresist layer.

[0011] Preferably, the window has an undercut structure.

[0012] Preferably, during the second tilting coating, the coating is applied from the side of the second channel closer to the window toward the side farther from the window.

[0013] Preferably, the edge where the window intersects with the second channel extends along the first direction.

[0014] Preferably, the window has a target edge extending along a third direction, the target edge connecting the edge of the window intersecting with the second channel, the third direction being inclined relative to the first direction and the second direction.

[0015] Preferably, the thickness of the second superconducting plate is greater than the thickness of the first superconducting plate, such that when the second superconducting plate is partially located on the barrier layer, the portion located on the barrier layer is interconnected with the portion located on the substrate.

[0016] Preferably, the opening shape of the window is rectangular, and the two adjacent edges of the rectangle extend along the first direction and the second direction, respectively.

[0017] Preferably, the mask further has a third channel exposing the substrate, the third channel extending along the second direction, the third channel being spaced apart from the window and the second channel, and intersecting with the first channel;

[0018] The step of forming a barrier layer on the surface of the first superconducting plate further includes:

[0019] A barrier layer is formed on the surface of the first superconducting wire;

[0020] After the second tilting coating, a third superconducting wire is formed in the third channel, overlapping with the first superconducting wire.

[0021] To solve the above-mentioned technical problems, the present invention also provides a Josephson knot obtained by the manufacturing method of the Josephson knot according to any one of the foregoing claims.

[0022] Unlike existing technologies, the Josephson junction manufacturing method provided by this invention involves setting a window and two vertical and interconnected channels on a photoresist. During each tilted deposition, a superconducting plate is formed within the window, and the overlapping area of ​​the two superconducting plates forms a Josephson junction. The area of ​​the Josephson junction is related to the size of the window but not to the width of the two channels. The size of the window can be made very large, with almost no size limit, while the width of the channels can be very small. A large-area Josephson junction can be formed after two tilted depositions, and no short circuit is formed within the window. This eliminates the limitation of the channel width on the resistance of the Josephson junction, making it particularly suitable for manufacturing Josephson junctions with low resistance.

[0023] The Josephson knot provided by this invention belongs to the same inventive concept as the method for manufacturing the Josephson knot, and therefore has the same beneficial effects, which will not be repeated here. Attached Figure Description

[0024] Figure 1 Electron micrograph of a Josephson junction manufactured using conventional processes in the prior art.

[0025] Figures 2-5 This is a schematic diagram of the manufacturing process of the Josephson junction provided in an embodiment of the present invention.

[0026] Figure 6 This is a schematic diagram of the cross-section of the window in the first direction.

[0027] Figures 7-9 This is a schematic diagram of the overlapping area of ​​the first and second superconducting plates under several different coating orientations.

[0028] Figure 10 This is a schematic diagram of a coating applied to a window that has a target edge extending along a third direction.

[0029] Figure 11 for Figure 10 Cross-sectional view along the MM direction.

[0030] Figures 12-15 A schematic diagram of the process flow for manufacturing a Josephson junction according to another embodiment of the present invention.

[0031] Explanation of reference numerals in the attached figures: 10-substrate, 20-mask, 21-first channel, 22-second channel, 23-window, 24-third channel, A-first direction, B-second direction, 31-first superconducting plate, 32-second superconducting plate, 33-barrier layer, 41-first superconducting wire, 42-second superconducting wire, JJ1, JJ2, JJ3, JJ4-Josephson junction, b1-target edge. Detailed Implementation

[0032] 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.

[0033] 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.

[0034] 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.

[0035] Please see Figure 1 This invention provides a method for manufacturing a Josephson knot, which includes the following steps:

[0036] S1: A mask is formed on a substrate. The mask has a window that exposes the substrate, a first channel, and a second channel. The first channel and the second channel extend along a first direction and a second direction that are perpendicular to each other, and both are connected to the window.

[0037] The substrate is an insulating material, which may include sapphire, silicon, silicon carbide, etc. In this embodiment, silicon is used as the substrate material.

[0038] The mask material can be photoresist or a hard material, such as metal. When the mask material is photoresist, the first channel, the second channel, and the window need to be formed on the photoresist through exposure and development. When the mask material is a hard material, the first channel, the second channel, and the window need to be formed through dry etching. In this embodiment, the mask includes a first photoresist layer and a second photoresist layer formed on the first photoresist layer, with the window penetrating through both the first and second photoresist layers. The first photoresist layer can be PMMA photoresist, and the second photoresist layer can be MMA photoresist.

[0039] For example, such as Figure 2As shown, it is a top view structural diagram after forming a mask on a substrate. A mask 20 is formed on the substrate 10. The mask 20 is composed of two layers of photoresist layers. The mask 20 has a first channel 21, a second channel 22, and a window 23. The first channel 21, the second channel 22, and the window 23 all penetrate through the mask 20 to expose the substrate 10. The first channel 21 extends along the first direction A, the second channel 22 extends along the second direction B, and the first direction A and the second direction B are perpendicular to each other. The first channel 21 and the second channel 22 communicate with the window 23.

[0040] S2: Perform inclined coating along the first direction to form a first superconducting plate in the window and a first superconducting wire connecting the first superconducting plate in the first channel.

[0041] Exemplarily, as Figure 3 As shown, it is a top view structural diagram after forming a first superconducting plate and a first superconducting wire through a mask. When performing inclined coating along the first direction A, set an appropriate coating angle, and the coating material is only deposited in the first channel 21 and the window 23, and finally a first superconducting plate 31 and a first superconducting wire 41 are formed.

[0042] Due to the inclined coating, the first superconducting plate 31 does not completely cover the substrate 10 exposed by the window 23. The first superconducting wire 41 may also include a part extending into the window 23 in addition to the part located in the first channel 21, which depends on the position of the first superconducting plate 31. If there is a gap between the first superconducting plate 31 and the first channel 21, the first superconducting wire 41 extends into the window 23 to connect with the first superconducting plate 31. If the first superconducting plate 31 connects the end edge of the first channel 21, the first superconducting wire 41 is completely located in the first channel 21 and just connects with the first superconducting plate 31. And the position of the first superconducting plate 31 depends on the coating orientation. If coating from the side of the first channel 21 far from the window 23 towards the side close to the window 23, there is a gap between the first superconducting plate 31 and the first channel 21. If coating from the side of the first channel 21 close to the window 23 towards the side far from the window 23, the first superconducting plate 31 connects the end edge of the first channel 21. Figure 3 The first superconducting plate 31 shown connects the end edge of the first channel 21.

[0043] In this embodiment, the window 23 has an undercut structure. The undercut structure, also called under cut, refers to a structure in which a part at the bottom of the mask opening is removed more, and the top opening size is smaller than the bottom opening size, so that the cross-sectional shape of the window 23 forms a "convex" shape. The undercut structure is beneficial for inclined coating, so that it will not be coated on the side wall of the opening, avoiding the phenomenon of the metal film edge warping. As Figure 3The diagram shows a cross-sectional view of the window in the first direction. The dashed lines with arrows indicate the orientation of the coating material. If the window 23 has an undercut structure, when performing tilted coating, by setting a suitable coating angle, a portion of the first superconducting plate 31 will be located on the substrate 10 that is blocked inside the window 23, but it will not be coated on the sidewall of the window 23, thus preventing the phenomenon of the edge of the first superconducting plate 31 from lifting up.

[0044] S3: A barrier layer is formed on the surface of the first superconducting plate.

[0045] The barrier layer and the substrate can be formed physically or chemically. In this embodiment, a chemical method is used. The coating material is typically aluminum or titanium nitride, which is oxidized through a first superconducting plate to form an alumina insulating layer. The alumina insulating layer can be formed by natural oxidation, dry oxidation, wet oxidation, or a combination of both. The thickness of the barrier layer can be adjusted by controlling the gas pressure and time during oxidation.

[0046] In other embodiments, an insulating barrier layer can be physically added directly to the first superconducting plate, such as by attaching a layer of aluminum oxide. Attachment is merely one possible arrangement and is not limited to this method. Furthermore, the use of aluminum oxide as the barrier layer is not limited to this method.

[0047] For example, such as Figure 4 The diagram shown is a top view of the structure after a barrier layer is formed on the first superconducting plate. After oxidation, a barrier layer 33 is formed on the surface of the first superconducting plate 31.

[0048] S4: An inclined coating is performed along the second direction to form a second superconducting plate that is at least partially located on the barrier layer within the window, and a second superconducting wire that connects the second superconducting plate is formed within the second channel.

[0049] For example, such as Figure 5 The diagram shown is a top view of the structure after the second superconducting plate and the second superconducting wire are formed by masking. When the coating is applied at an angle along the second direction B, and a suitable coating angle is set, the coating material is deposited only in the second channel 22 and the window 23, ultimately forming the second superconducting plate 32 and the second superconducting wire 42.

[0050] Due to the inclined coating, the second superconducting plate 32 will not completely cover the substrate 10 exposed by the window 23. The second superconducting wire 42, in addition to the portion located within the second channel 22, may also include a portion extending into the window 23, depending on the position of the second superconducting plate 32. If there is a gap between the second superconducting plate 32 and the second channel 22, the second superconducting wire 42 extends into the window 23 and connects with the second superconducting plate 32. If the second superconducting plate 32 connects to the end edge of the second channel 22, the second superconducting wire 42 is completely located within the second channel 22 and connects precisely to the first superconducting plate 31. The position of the second superconducting plate 32 also depends on the coating orientation. If the coating is applied from the side of the second channel 22 away from the window 23 towards the side closer to the window 23, there is a gap between the second superconducting plate 32 and the second channel 22. If the coating is applied from the side of the second channel 22 closer to the window 23 towards the side away from the window 23, the second superconducting plate 32 connects to the end edge of the second channel 22. Figure 5 The second superconducting plate 32 shown is connected to the end edge of the second channel 22.

[0051] Through the above-described method, the Josephson junction manufacturing method of this invention involves setting a window and two vertical and interconnected channels on the photoresist. Each time the coating is tilted, a superconducting plate is formed within the window. The overlapping area of ​​the two superconducting plates forms a Josephson junction. The area of ​​the Josephson junction is related to the size of the window but not to the width of the two channels. The size of the window can be made very large, with almost no size limitation. The width of the channels can be very small. After two tilted coatings, a large-area Josephson junction can be formed without forming a short circuit within the window. This eliminates the limitation of the channel width on the resistance of the Josephson junction, making it particularly suitable for manufacturing Josephson junctions with low resistance.

[0052] Although the first tilted coating is along the first direction and the second tilted coating is along the second direction, the orientation during coating can change. Under different coating orientations, the shape of the overlapping area between the first and second superconducting plates is different, except... Figure 5 Besides the coating orientation shown, other coating orientations can also be used. For example... Figures 7 to 9 The diagram shown is a schematic of the overlapping area of ​​the first and second superconducting plates under several different coating orientations. The barrier layer 33 is omitted in the diagram. Figure 7 In the process, the first superconducting plate 31 is formed by coating from the side of the first channel 21 away from the window 23 toward the side closer to the window 23 (hereinafter referred to as left-facing coating, and other coating orientations are distinguished as left, right, up, and down based on this). The second superconducting plate 32 is formed by coating downwards. The first superconducting plate 31 and the second superconducting plate 32 partially overlap to form a Josephson junction JJ1. Figure 8In the process, the first superconducting plate 31 is coated to the left and the second superconducting plate 32 is coated to the top. The first superconducting plate 31 and the second superconducting plate 32 partially overlap to form a Josephson junction JJ2. In this case, the first superconducting wire 32 and the second superconducting wire 42 will also overlap to form another Josephson junction JJ3. The Josephson junction JJ2 and the Josephson junction JJ3 are connected in parallel. The parallel resistance of the two Josephson junctions JJ2 and JJ3 is the total resistance. Figure 9 In this configuration, the first superconducting plate 31 is coated to the right, and the second superconducting plate 32 is coated upwards. The first superconducting plate 31 and the second superconducting plate 32 partially overlap, and the second superconducting wire 42 also partially overlaps with the first superconducting plate 31. The two overlapping areas together form the Josephson junction JJ4. It should be noted that in all these coating orientations, the window 23 has an undercut structure.

[0053] In the embodiments of this application, during the second tilting deposition, the deposition is performed from the side of the second channel 22 closest to the window 23 toward the side furthest from the window 23, meaning the second superconducting plate 32 is deposited downwards. The edge where the window 23 intersects with the second channel 22 can extend along the first direction A, which facilitates subsequent observation of the Josephson junction using an electron microscope. However, since the deposition surface is no longer planar during the second tilting deposition, a height difference is formed between the first superconducting plate 31 and the substrate 10. This may cause a break in the second superconducting plate 32 during the second tilting deposition.

[0054] To avoid the occurrence of fault lines, in this embodiment, as follows: Figure 10 As shown, window 23 has a target edge b1 extending along a third direction C. The target edge connects the edge where window 23 intersects with the second channel 22, and is inclined relative to the first direction A and the second direction B. Since window 23 has an undercut structure and the target edge b1 extends along the third direction C, after the second tilting coating, both the first superconducting plate 31 and the second superconducting plate 32 have bevels parallel to the target edge b1. During the second tilting coating... Figure 10 The second superconducting plate 32 at the dashed box may have a fault. Specifically, through... Figure 11 As shown in the cross-sectional view, the second superconducting plate 32 on the left side of the first superconducting plate 31 is disconnected from the second superconducting plate 32 located on the first superconducting plate 31. However, due to the presence of the target edge b1, the second superconducting plate 32 will "climb" at the inclined side of the first superconducting plate 31, ensuring that the second superconducting plates 32 on both sides of the inclined side are not disconnected. Therefore, the Josephson junction will not experience a signal break, as shown in the figure. Figure 10 The dashed curve in the diagram represents the signal transmission path. The signal is transmitted through the hypotenuse of the first superconducting plate 31, bypassing [the signal path]. Figure 10 No signal interruption was observed in the first superconducting plate 31 located within the dashed box. Specifically, through... Figure 11As can be seen from the cross-sectional view shown, the second superconducting plate 32 on the right side of the first superconducting plate 31 is connected to the second superconducting plate 32 located on the first superconducting plate 31.

[0055] In other embodiments of this application, the thickness of the second superconducting plate 32 is greater than the thickness of the first superconducting plate 31, such that when the second superconducting plate 32 is partially located on the barrier layer 33, the portion located on the barrier layer 33 is interconnected with the portion located on the substrate 10. Since the thickness of the second superconducting plate 32 is greater than the thickness of the first superconducting plate 31, on the side of the first superconducting plate 31 facing away from the coating, the second superconducting plate 32, due to its sufficiently large thickness, can interconnect the portion located on the barrier layer 33 with the portion located on the substrate 10. Specifically, through… Figure 11 As shown in the cross-sectional view, provided the thickness of the second superconducting plate 32 meets the requirements, the second superconducting plate 32 on the left side of the first superconducting plate 31 is connected to the second superconducting plate 32 located on the first superconducting plate 31. Furthermore, the opening shape of the window 23 is rectangular, with its two adjacent edges extending along the first direction A and the second direction B, respectively. Because the opening shape of the window 23 is rectangular, the Josephson junction can be a rectangle or a combination of multiple rectangles, making it easier to calculate the area of ​​the Josephson junction and thus facilitating its design.

[0056] Please see Figures 12 to 15 Another embodiment of the present invention provides a method for manufacturing a Josephson junction. This method is based on the Josephson junction manufacturing method of the foregoing embodiment and includes all the technical features of the foregoing embodiment. The difference lies in that the mask further has a third channel exposing the substrate. The third channel extends along a second direction, is spaced apart from the window and the second channel, and intersects with the first channel. For example, as... Figure 12 As shown, the mask 20 has a first channel 21, a second channel 22, a window 23, and a third channel 24. All three channels penetrate the mask 20 to expose the substrate 10. The first channel 21 extends along a first direction A, and the second and third channels 22 extend along a second direction B. The first and second directions A and B are perpendicular to each other. The first and second channels 21 connect to the window 23, and the third channel 24 intersects with the first channel 21.

[0057] The step of forming a barrier layer on the surface of the first superconducting plate, i.e., step S3, further includes: forming a barrier layer on the surface of the first superconducting wire. For example, as... Figure 13As shown, the first superconducting plate 31 and the first superconducting wire 41 are formed within the window 23 and the first channel 21. When the barrier layer is formed by oxidation, since the first superconducting wire 41 and the first superconducting plate 31 are both made of superconducting material, the surface of the first superconducting wire 41 will also be oxidized to form the barrier layer 33. For example, as... Figure 14 As shown, a barrier layer 33 is formed on the surface of both the first superconducting plate 31 and the first superconducting wire 41.

[0058] After the second tilting coating, a third superconducting wire is formed within the third channel, overlapping with the first superconducting wire. The first and third superconducting wires overlap, and simultaneously the second and first superconducting plates overlap, thus enabling the simultaneous fabrication of two Josephson junctions. For example, as shown... Figure 15 As shown, when the coating is tilted along the second direction B, and a suitable coating angle is set, the coating material is deposited only in the second channel 22, the third channel 24, and the window 23, ultimately forming the second superconducting plate 32, the second superconducting wire 42, and the third superconducting wire 43. The second superconducting plate 32 overlaps with the first superconducting plate 31 to form a Josephson junction, and the third superconducting wire 43 overlaps with the first superconducting wire 41 to form another Josephson junction, thus forming two Josephson junctions. If the two Josephson junctions are connected in parallel, such a structure is also called a superconducting quantum interference device (SQUID).

[0059] Since the area of ​​the Josephson junction on the left side of the diagram is related to the size of window 23, and the size of window 23 is not limited, the resistance of the Josephson junction on the left side of the diagram can be designed to be very small. Since the area of ​​the Josephson junction on the right side of the diagram is related to the linewidth of the first superconducting wire 41 and the third superconducting wire 43, and the widths of the first channel 21 and the third channel 24 are limited, the Josephson junction on the right side of the diagram is designed to be larger. Thus, the two Josephson junctions in the superconducting quantum interference device exhibit a high degree of resistance asymmetry.

[0060] For qubits using a superconducting quantum interference device (SQI), the position with the highest frequency is called the sweet spot, also known as the degeneracy point. Qubits operating at the degeneracy point typically have a high decoherence time, but once they deviate from the degeneracy point, the decoherence time decreases significantly. However, due to various factors, the operating frequency of qubits is usually not at the degeneracy point. The frequency of qubits at non-degenerate points is related to the asymmetry of the SQI. The smaller the asymmetry of the SQI, the lower the frequency of qubits at non-degenerate points; the larger the asymmetry, the higher the frequency of qubits at non-degenerate points. Using the manufacturing method of this embodiment, by adjusting the window size, two Josephson junctions with significant resistance differences can be fabricated to obtain a superconducting quantum interference device with high asymmetry. This can increase the frequency of qubits at non-degenerate points, improve the decoherence time, and contribute to achieving stronger quantum information processing capabilities.

[0061] The present invention also protects a Josephson knot, which is obtained by the manufacturing method of the Josephson knot of any of the foregoing embodiments.

[0062] 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.

[0063] 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 a Josephson knot, characterized in that, include: A mask is formed on a substrate, the mask having a window exposing the substrate, a first channel and a second channel, the first channel and the second channel extending along a first direction and a second direction that are perpendicular to each other, and both communicating with the window; An inclined coating is applied along the first direction to form a first superconducting plate within the window and a first superconducting wire connecting the first superconducting plate within the first channel. A barrier layer is formed on the surface of the first superconducting plate; An inclined coating is performed along the second direction to form a second superconducting plate that is at least partially located on the barrier layer within the window, and a second superconducting wire that connects the second superconducting plate is formed within the second channel.

2. The manufacturing method according to claim 1, characterized in that, The mask includes a first photoresist layer and a second photoresist layer formed on the first photoresist layer, and the window extends through the first photoresist layer and the second photoresist layer.

3. The manufacturing method according to claim 1 or 2, characterized in that, The window has an undercut structure.

4. The manufacturing method according to claim 3, characterized in that, During the second tilt coating, the coating is applied from the side of the second channel closest to the window toward the side furthest from the window.

5. The manufacturing method according to claim 4, characterized in that, The edge where the window intersects with the second channel extends along the first direction.

6. The manufacturing method according to claim 5, characterized in that, The window has a target edge extending along a third direction, the target edge connecting the edge of the window that intersects with the second channel, the third direction being inclined relative to the first direction and the second direction.

7. The manufacturing method according to claim 5, characterized in that, The thickness of the second superconducting plate is greater than that of the first superconducting plate, such that when the second superconducting plate is partially located on the barrier layer, the portion located on the barrier layer is interconnected with the portion located on the substrate.

8. The manufacturing method according to claim 5, characterized in that, The window opening is rectangular, and the two adjacent edges of the rectangle extend along the first direction and the second direction, respectively.

9. The manufacturing method according to any one of claims 1 to 8, characterized in that, The mask also has a third channel exposing the substrate, the third channel extending along the second direction, the third channel being spaced apart from the window and the second channel, and intersecting with the first channel; The step of forming a barrier layer on the surface of the first superconducting plate further includes: A barrier layer is formed on the surface of the first superconducting wire; After the second tilting coating, a third superconducting wire is formed in the third channel, overlapping with the first superconducting wire.

10. A Josephson knot obtained by a method of manufacturing a Josephson knot according to any one of claims 1 to 9.

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