Mask and method of manufacturing the same, josephson junction device and method of manufacturing the same

Abstract

The application discloses a mask and a manufacturing method thereof, a Josephson junction device and a manufacturing method thereof. The mask comprises a first photoresist layer on an upper layer and a second photoresist layer on a lower layer, the first photoresist layer is formed with a first groove and a second groove which are perpendicular to each other but not connected, the second photoresist layer is formed with a third groove and a fourth groove which are perpendicular to each other and connected, the extension direction of the first groove is consistent with that of the third groove and the first groove is within the opening range of the third groove, and the extension direction of the second groove is consistent with that of the fourth groove and the second groove is within the opening range of the fourth groove. In the manufacturing of the Josephson junction, a first superconducting strip is formed through the first groove, a second superconducting strip is formed through the second groove, the second superconducting strip is in contact with the side surface insulating layer of the first superconducting strip, and thus a superconductor-insulator-superconductor structure, i.e. the Josephson junction, is formed in the horizontal direction, so that the application can reduce the influence of the line width on the area of the Josephson junction and make the resistance of the Josephson junction more in line with the expectation.

Description

Technical Field

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

[0002] Josephson junctions are one of the key components in superconducting quantum chips. The performance of superconducting quantum chips largely depends on high-quality, high-stability Josephson junctions. A Josephson junction is composed of a stacked structure of superconductors, insulators, and superconductors.

[0003] Current Josephson junction manufacturing processes typically involve creating a vertical stack of two superconductors perpendicular to the substrate. The area of ​​the overlapping region is the area of ​​the Josephson junction, which is determined by the linewidth of the superconductor. However, Josephson junctions are micro / nano devices, and the linewidth of the superconductor is extremely small. With current manufacturing processes, it is difficult to precisely control the linewidth of the superconductor, significantly impacting the area of ​​the Josephson junction and directly leading to substantial errors in its resistance. Summary of the Invention

[0004] The purpose of this invention is to provide a mask and its manufacturing method, and a Josephson junction device and its manufacturing method, to solve the problem that the area of ​​the Josephson junction is greatly affected by the superconductor linewidth in the prior art, and to reduce the influence of the superconductor linewidth on the area of ​​the Josephson junction.

[0005] To solve the above-mentioned technical problems, the present invention provides a mask including an upper first photoresist layer and a lower second photoresist layer. The first photoresist layer has a first trench and a second trench that are perpendicular to each other but not connected. The second photoresist layer has a third trench and a fourth trench that are perpendicular to each other and connected. The first trench and the third trench extend in the same direction and are within the opening range of the third trench. The second trench and the fourth trench extend in the same direction and are within the opening range of the fourth trench.

[0006] Preferably, there are two second grooves and two fourth grooves, with each second groove corresponding to one of the two fourth grooves, and the two second grooves located on the same side of the first groove.

[0007] Preferably, the cross-sectional shape and opening shape of the first groove, the second groove, the third groove and the fourth groove are all rectangular.

[0008] Preferably, the openings of the first groove and the third groove coincide, and the openings of the second groove and the fourth groove coincide in a direction perpendicular to the extension direction.

[0009] To solve the above-mentioned technical problems, the present invention also provides a method for manufacturing a mask, comprising:

[0010] A first photoresist layer and a second photoresist layer are formed by stacking them on top of each other. The first photoresist layer and the second photoresist layer use the same photoresist, and the exposure dose is higher than that of the second photoresist layer.

[0011] A first trench and a second trench that are perpendicular to each other but not connected are formed on the first photoresist layer by photolithography, and a third trench and a fourth trench that are perpendicular to each other and connected are formed on the second photoresist layer; the first trench and the third trench extend in the same direction and are within the opening range of the third trench, and the second trench and the fourth trench extend in the same direction and are within the opening range of the fourth trench.

[0012] Preferably, there are two second grooves and two fourth grooves, with each second groove corresponding to one of the two fourth grooves, and the two second grooves located on the same side of the first groove.

[0013] Preferably, the step of forming mutually perpendicular but non-connected first and second trenches on the first photoresist layer by photolithography, and forming mutually perpendicular and connected third and fourth trenches on the second photoresist layer, includes:

[0014] A first strip region, a second strip region perpendicular to the first strip region, and an intermediate region connecting the first strip region and the second strip region are defined on the first photoresist layer.

[0015] The first and second photoresist layers of the first and second strip regions are exposed, as is the second photoresist layer of the intermediate region;

[0016] The first photoresist layer of the first strip region and the second strip region is removed by development, and a first trench and a second trench that are perpendicular to each other but not connected are formed on the first photoresist layer. The second photoresist layer of the first strip region, the second strip region and the intermediate region are removed, and a third trench and a fourth trench that are perpendicular to each other and connected are formed on the second photoresist layer.

[0017] To address the aforementioned technical problems, the present invention also provides a method for manufacturing a Josephson junction device, comprising:

[0018] Provide substrate;

[0019] A mask according to any of the foregoing methods is disposed on a substrate, or a mask is formed on the substrate according to the mask manufacturing method according to any of the foregoing methods;

[0020] Inclined evaporation is performed along the extension direction of the first trench to form a first superconducting strip on the substrate with a height not lower than that of the second photoresist layer;

[0021] An insulating layer is formed on the side of the first superconducting strip facing the fourth trench by oxidation;

[0022] The second superconducting strip is formed on the substrate by oblique evaporation from one end away from the first trench to the other end, with its end face facing the first superconducting strip and in contact with the insulating layer in a direction parallel to the surface of the substrate, thereby forming a Josephson junction.

[0023] Preferably, before the mask is set or formed, the manufacturing method further includes:

[0024] Grooves are etched into the surface of the substrate;

[0025] A third photoresist layer flush with the surface of the substrate is filled in the groove. The third photoresist layer uses a different photoresist than the first and second photoresist layers.

[0026] After the mask is set or formed, in the area where the first trench and the second trench are not connected, the area within a preset distance from the first trench is located above the groove, and the first trench and the second trench at least partially expose the substrate;

[0027] After the second superconducting strip is formed, the manufacturing method further includes:

[0028] Remove the mask and the third photoresist layer to suspend the Josephson junction above the groove.

[0029] To solve the above-mentioned technical problems, the present invention also provides a Josephson junction device obtained by the manufacturing method of any of the foregoing methods.

[0030] Unlike existing technologies, the mask or mask manufacturing method provided by this invention forms mutually perpendicular but non-connected first and second trenches on the upper first photoresist layer, and mutually perpendicular and connected third and fourth trenches on the lower second photoresist layer. The first trench is within the opening range of the third trench and extends in the same direction, and the second trench is within the opening range of the fourth trench and extends in the same direction. Therefore, the non-connected portion between the first and second trenches forms a suspension. During the fabrication of the Josephson junction, a first superconducting strip is formed by tilted evaporation along the extension direction of the first trench. An insulating layer is formed on the side by oxidation. Finally, a second superconducting strip is formed by inclined evaporation along the extension direction of the second trench from the side away from the first trench to the other side. The second superconducting strip passes under the suspension and contacts the insulating layer, thus forming a superconductor-insulator-superconductor structure, namely a Josephson junction, in a direction parallel to the substrate surface. Since the area of ​​the Josephson junction depends only on the thickness and width of the second superconducting strip and is independent of the linewidth of the first superconducting strip, and the thickness of the second superconducting strip is easier to control than its width, the influence of the linewidth on the area of ​​the Josephson junction can be reduced, making the resistance of the Josephson junction more in line with expectations.

[0031] The method for manufacturing Josephson junction devices provided by this invention, as well as the Josephson junction devices and masks and their manufacturing methods, belong to the same inventive concept and have the same technical effects, and will not be described in detail here. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of the mask provided in the first embodiment of the present invention.

[0033] Figure 2 This is an exploded view of the mask structure provided in the first embodiment of the present invention.

[0034] Figure 3 a to Figure 3 c is a schematic diagram of the manufacturing method of the mask provided in the second embodiment of the present invention.

[0035] Figure 4 a to Figure 4 d is a schematic diagram of the manufacturing method of the Josephson junction device provided in the third embodiment of the present invention.

[0036] Figure 5 for Figure 4 A top-view diagram of a.

[0037] Figure 6 for Figure 4 A top-view diagram of d. Detailed Implementation

[0038] 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.

[0039] 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.

[0040] 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.

[0041] Please refer to Figure 1 and Figure 2 The first embodiment of the present invention provides a mask. The mask includes an upper first photoresist layer 10 and a lower second photoresist layer 20. The first photoresist layer 10 has a first trench 11 and a second trench 12 that are perpendicular to each other but not connected. The second photoresist layer 20 has a third trench 21 and a fourth trench 22 that are perpendicular to each other and connected. The first trench 11 extends in the same direction as the third trench 21 and is within the opening range of the third trench 21. The second trench 12 extends in the same direction as the fourth trench 22 and is within the opening range of the fourth trench 22.

[0042] Since the fourth trench 22 is connected to the third trench 21 within the opening range of the first trench 11 and the third trench 21, while the second trench 12 is not connected to the first trench 11, the first photoresist layer 10 in the area where the second trench 12 and the first trench 11 are not connected will be suspended above the fourth trench 22, forming a suspended photoresist.

[0043] In this embodiment, the cross-sectional shape and opening shape of the first trench 11, the second trench 12, the third trench 21, and the fourth trench 22 are all rectangular. Photoresist has excellent properties in terms of film formation, imprinting performance (such as hardness and viscosity, curing speed, interface properties, etc.), and corrosion resistance, making it easy to fabricate rectangular trenches. Since the openings of the first trench 11 and the second trench 12 are both rectangular and perpendicular to each other, the end walls of the second trench 12 are parallel to the side walls of the first trench 11, making the top view shape of the suspension between the second trench 22 and the first trench 11 also rectangular.

[0044] To facilitate the formation of the grooves, in this embodiment, the openings of the first groove 11 and the third groove 21 coincide, and the openings of the second groove 12 and the fourth groove 22 coincide in the direction perpendicular to the extension direction. That is, the opening shapes of the first groove 11 and the third groove 21 are the same, and their openings coincide in the vertical direction; specifically, the length L1 of the first groove 11 is the same as the length L3 of the third groove 21, and the width W1 of the first groove 11 is the same as the width W3 of the third groove 21. The opening width of the fourth groove 22 in the direction perpendicular to the extension direction is the same as that of the second groove 12, and their openings coincide in the vertical direction; that is, the width W2 of the second groove 12 is the same as the width W4 of the fourth groove 22. The length L4 of the fourth groove 22 in its extension direction can be the length L2 of the second groove 12 plus the length L of the suspension.

[0045] The mask in this embodiment of the invention comprises a double-layer photoresist layer. The upper photoresist layer has a first trench and a second trench that are perpendicular to each other but not connected. The lower photoresist layer has a third trench and a fourth trench that are perpendicular to each other and connected. The first trench and the third trench correspond to each other, and the second trench and the fourth trench correspond to each other. Thus, a suspension is formed above the fourth trench in the portion between the first trench and the second trench. During the fabrication of the Josephson junction, a first superconducting strip can be formed through the first trench, and a second superconducting strip can be formed through the second trench. The second superconducting strip passes under the suspension. The sides of the strip can be oxidized to form an insulating layer, thus forming a superconductor-insulator-superconductor structure in the horizontal direction, namely the Josephson junction. The area of ​​the Josephson junction is the width of the second trench and the height of the fourth trench, and is independent of the width of the first trench and the third trench. In other words, the area of ​​the Josephson junction depends only on the thickness and width of the second superconducting strip, and is independent of the linewidth of the first superconducting strip. The thickness of the second superconducting strip is easier to control than its width, thereby reducing the influence of the linewidth on the area of ​​the Josephson junction and making the resistance of the Josephson junction more in line with expectations.

[0046] Since the second trench 12 determines the number of Josephson junctions subsequently manufactured, in order to manufacture two Josephson junctions simultaneously, in this embodiment, there are two second trenches 12 and two fourth trenches 22, with each second trench 12 corresponding to one of the two fourth trenches 22, and the two second trenches 12 are located on the same side of the first trench 11. The two second trenches 12 can form two second superconducting strips, and both second superconducting strips are in contact with the insulating layer on the side of the first superconducting strip, thereby forming two Josephson junctions. If the two second superconducting strips are electrically connected together, then the two Josephson junctions form a parallel relationship, thus forming a superconducting quantum interference device (SQUID).

[0047] Reference Figure 3 a, and combined Figure 1 and Figure 2 The second embodiment of this application provides a method for manufacturing a mask. The manufacturing method includes the following steps:

[0048] S11: Forming a first photoresist layer and a second photoresist layer stacked on top of each other. The first and second photoresist layers use the same photoresist, and the exposure dose of the first photoresist layer is higher than that of the second photoresist layer. For example, Figure 3 Figure a shows a cross-sectional view after the formation of the first and second photoresist layers. The first photoresist layer 10 is located on the upper layer, and the second photoresist layer 20 is located on the lower layer. Specifically, the first photoresist layer 10 and the second photoresist layer 20 can be formed by spin coating.

[0049] S12: A first trench and a second trench, perpendicular to each other but not connected, are formed on the first photoresist layer by photolithography, and a third trench and a fourth trench, perpendicular to each other and connected, are formed on the second photoresist layer. The first trench and the third trench extend in the same direction and are within the opening range of the third trench, and the second trench and the fourth trench extend in the same direction and are within the opening range of the fourth trench. Since the first photoresist layer 10 and the second photoresist layer 20 use the same photoresist, they can be exposed simultaneously. Because the exposure dose of the first photoresist layer 10 is higher than that of the second photoresist layer 20, the exposure dose in the region between the first trench 11 and the second trench 12 can be controlled, so that the second photoresist layer 20 in this region is exposed while the first photoresist layer 10 is not exposed. The first photoresist layer 10 and the second photoresist layer 20 in other locations are exposed simultaneously, ultimately forming a... Figure 1 and Figure 2 The mask shown.

[0050] Specifically, see Figure 3 b and Figure 3 c, and combined Figure 1 and Figure 2Step S12 includes forming a first trench and a second trench that are perpendicular to each other but not connected on the first photoresist layer by photolithography, and forming a third trench and a fourth trench that are perpendicular to each other and connected on the second photoresist layer.

[0051] S121: A first stripe region, a second stripe region perpendicular to the first stripe region, and an intermediate region connecting the first stripe region and the second stripe region are defined on the first photoresist layer. Wherein, as... Figure 3 Figure b shows a schematic diagram after determining the first and second strip regions. The first strip region 11A and the second strip region 12A are perpendicular to each other but not connected, and the area between them is the intermediate region 13A. The first strip region 11A, the second strip region 12A, and the intermediate region 13A can be determined by a mask.

[0052] S122: Expose both the first and second photoresist layers in the first and second stripe regions, and expose the second photoresist layer in the middle region. For example... Figure 3 Figure c shows a cross-sectional schematic diagram of the exposure of the first and second photoresist layers. The white areas in the figure represent the exposure range, and the arrows represent the exposure dose. The exposure dose of the first strip region 11A and the second strip region 12A is represented by S1, and the exposure dose of the middle region 13A is represented by S2. The exposure dose S1 is at least higher than the exposure dose of the first photoresist layer 10, so both the first photoresist layer 10 and the second photoresist layer 20 in the first strip region 11A and the second strip region 12A are exposed. The exposure dose S2 is higher than the exposure dose of the second photoresist layer 20 but lower than the exposure dose of the first photoresist layer 10, so the second photoresist layer 20 in the middle region 13A is exposed, and the first photoresist layer 10 is not exposed.

[0053] S123: By developing and removing the first photoresist layer of the first stripe region and the second stripe region, a first trench and a second trench that are perpendicular to each other but not connected are formed on the first photoresist layer; and by removing the second photoresist layer of the first stripe region, the second stripe region, and the intermediate region, a third trench and a fourth trench that are perpendicular to each other and connected are formed on the second photoresist layer. Wherein, as... Figure 3As shown in Figure c, the photoresist in the white area is removed. Specifically, after the first photoresist layer 10 of the first strip region 11A is removed, a first trench 11 is formed. After the first photoresist layer 10 of the second strip region 12A is removed, a second trench 12 is formed. After the second photoresist layer 20 of the first strip region 11A is removed, a third trench 21 is formed. After the second photoresist layers 20 of the second strip region 12A and the middle region 13A are removed, a fourth trench 22 is formed because the removed photoresist is continuous. The first photoresist layer 10 of the middle region 13A is not removed, thus forming a suspension above the fourth trench 22, ultimately forming a... Figure 1 and Figure 2 The mask shown.

[0054] The mask manufacturing method of this invention produces a mask comprising two photoresist layers. The upper photoresist layer has a first trench and a second trench that are perpendicular to each other but not connected. The lower photoresist layer has a third trench and a fourth trench that are perpendicular to each other and connected. The first trench and the third trench correspond to each other, and the second trench and the fourth trench correspond to each other. Thus, a suspension is formed above the fourth trench in the portion between the first trench and the second trench. During the fabrication of a Josephson junction, a first superconducting strip can be formed through the first trench, and a second superconducting strip can be formed through the second trench. The second superconducting strip passes under the suspension. The sides of the first superconducting strip can be oxidized to form an insulating layer, thereby forming a superconductor-insulator-superconductor structure in the horizontal direction, namely the Josephson junction. The area of ​​the Josephson junction is the width of the second trench and the height of the fourth trench, and is independent of the width of the first trench and the third trench. In other words, the area of ​​the Josephson junction depends only on the thickness and width of the second superconducting strip, and is independent of the linewidth of the first superconducting strip. The thickness of the second superconducting strip is easier to control than its width, thereby reducing the influence of the linewidth on the area of ​​the Josephson junction and making the resistance of the Josephson junction more in line with expectations.

[0055] Please refer to Figure 4 a to Figure 4 d. A third embodiment of this application provides a method for manufacturing a Josephson junction device. The manufacturing method includes the following steps:

[0056] S21: Provide a substrate. For example, the substrate may be a silicon substrate or a sapphire substrate.

[0057] S22: The mask of the first embodiment described above is disposed on the substrate, or the mask is formed on the substrate according to the mask manufacturing method of the second embodiment described above. Wherein, as... Figure 4 Figure a shows a schematic diagram after a mask has been formed on the substrate. Figure 1 Taking the mask shown as an example, the mask is formed on the substrate 100.

[0058] S23: Tilted evaporation is performed along the extension direction of the first trench to form a first superconducting strip on the substrate with a height not less than that of the second photoresist layer. Wherein, as... Figure 4 Figure b shows a schematic diagram after the first superconducting strip is formed on the substrate. It should be noted that the mask is omitted in the figure for ease of demonstration of the Josephson junction formation process. Similarly, the subsequent... Figure 4 c and Figure 4 The mask is also omitted in step d. Due to the inclined evaporation along the extension direction of the first trench 11, the evaporated material will only be deposited on the substrate 100 exposed by the first trench 11, and will not be deposited on the substrate 100 exposed by the second trench 12, thereby forming a first superconducting strip 210 on the substrate 100 within the first trench 11. The height of the first superconducting strip 210 is not lower than that of the second photoresist layer 20, therefore, the first superconducting strip 210 will block the space below the photoresist.

[0059] S24: An insulating layer is formed by oxidation on the side of the first superconducting strip facing the fourth trench. Wherein, as... Figure 4 Figure c shows a schematic diagram after an insulating layer is formed on the side of the first superconducting strip. The substrate 100 can be oxidized in an oxide chamber. Since the side of the first superconducting strip 210 facing the fourth trench 22 is exposed in the fourth trench 22 below the suspension, the superconducting material will form an oxide layer on the surface when it comes into contact with oxygen, thereby forming an insulating layer 230 (shaded part in the figure) on the side of the first superconducting strip 210.

[0060] S25: An inclined evaporation process is performed from one end of the second trench away from the first trench to the other, forming a second superconducting strip on the substrate with its end face facing the first superconducting strip and in contact with the insulating layer in a direction parallel to the substrate surface, thus constituting a Josephson junction. Wherein, as... Figure 4 Figure d shows a schematic diagram after the second superconducting strip is formed on the substrate. Arrow A indicates the inclined evaporation direction of the second superconducting strip 220. Due to the inclined evaporation along the extension direction of the second trench 12, the evaporated material only deposits on the substrate 100 exposed by the second trench 12, and not on the first superconducting strip 210 within the first trench 11. Thus, the second superconducting strip 220 is formed on the substrate 100 within the second trench 12. Furthermore, because the evaporation is inclined from one end of the second trench 12 away from the first trench 11 to the other, the evaporated material enters the space below the suspension. The formed second superconducting strip 220 then passes through this space and contacts the insulating layer 230, ultimately forming a superconductor-insulator-superconductor structure, i.e., a Josephson junction, in a direction parallel to the surface of the substrate 100. When the cross-sectional shape of the second superconducting strip 220 is rectangular, the area of ​​the Josephson junction is the height of the second superconducting strip 220 multiplied by its width.

[0061] In practical applications, the performance of Josephson junctions can sometimes be affected by substrate 100 losses. To reduce the performance loss of Josephson junctions, in this embodiment, the manufacturing method further includes the following steps before mask setting or formation:

[0062] S22A: Grooves are etched into the substrate surface. For example, Figure 4 As shown in b, a groove 110 is formed on the substrate 100.

[0063] S22B: A third photoresist layer, flush with the substrate surface, is filled within the groove. This third photoresist layer uses a different photoresist than the first and second photoresist layers. Because the third photoresist layer (not indicated by reference numerals) uses a different photoresist than the first and second photoresist layers, the photolithography process of the first and second photoresist layers will not affect the third photoresist layer when forming the mask using a mask manufacturing method. The first and second photoresist layers may be, for example, electron beam photoresist, and the third photoresist layer may be, for example, ultraviolet photoresist.

[0064] After the mask is set or formed, in the non-connected region between the first trench and the second trench, the region within a predetermined distance from the first trench is located above the groove, and the first trench and the second trench at least partially expose the substrate. Wherein, as... Figure 5 As shown, is Figure 4 A top view of groove 110 is shown. To show the complete outline of the groove, the unexposed portion is represented by dashed lines. The non-connected area between the first groove 11 and the second groove 12 is a rectangular area of ​​length L and width W2. Within this rectangular area, the region within a predetermined distance h from the first groove 11 is located above the groove 110. The predetermined distance h can be less than or equal to the length L; that is, the rectangular area can be partially or entirely located above the groove 110. The first groove 11 and the second groove 12 can fully or partially expose the substrate 100. The figure shows two grooves 110; one groove 110 is used for illustration. The middle portion of the first groove 11 exposes the groove 110, while the other portions expose the substrate 100. The left side of the second groove 12 exposes the groove 110, and the right side exposes the substrate 100.

[0065] After the second superconducting strip is formed, the manufacturing method also includes:

[0066] S26: Remove the mask and third photoresist layer, leaving the Josephson junction suspended above the groove. For example, Figure 6 As shown, is Figure 4As shown in the top view of diagram d, the groove 110 is filled with a third photoresist layer. The portions of the first superconducting strip 210 and the second superconducting strip 220 located above the groove 110 are formed on the third photoresist layer, thus the first and second superconducting strips 210 and 220 are formed entirely on the same plane, i.e., on the plane containing the surface of the substrate 100. After removing the mask and the third photoresist layer, because at least a portion of the insulating layer 230 and the first and second superconducting strips 210 and 220 that are in contact with the insulating layer 230 are located above the groove 110, the resulting Josephson junction is suspended above the groove 110.

[0067] It should be noted that all the above figures are merely schematic diagrams and do not represent actual proportions. The first superconducting strip 210 and the second superconducting strip 220 can be sufficiently small relative to the substrate 100, and the insulating layer 230 can also be sufficiently thin, typically with a thickness on the order of several nanometers.

[0068] 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.

[0069] 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 junction device, characterized in that, include: Provide substrate; A mask is disposed on a substrate, or a mask is formed on the substrate according to a mask manufacturing method. The mask includes an upper first photoresist layer and a lower second photoresist layer. The first photoresist layer has a first trench and a second trench that are perpendicular to each other but not connected. The second photoresist layer has a third trench and a fourth trench that are perpendicular to each other and connected. The method for manufacturing the mask includes: forming a first photoresist layer and a second photoresist layer stacked on top of each other, wherein the first photoresist layer and the second photoresist layer use the same photoresist and the exposure dose of the first photoresist layer is higher than that of the second photoresist layer; forming a first trench and a second trench that are perpendicular to each other but not connected on the first photoresist layer by photolithography, and forming a third trench and a fourth trench that are perpendicular to each other and connected on the second photoresist layer; wherein the first trench and the third trench extend in the same direction and are within the opening range of the third trench, and the second trench and the fourth trench extend in the same direction and are within the opening range of the fourth trench; Inclined evaporation is performed along the extension direction of the first trench to form a first superconducting strip on the substrate with a height not lower than that of the second photoresist layer; An insulating layer is formed on the side of the first superconducting strip facing the fourth trench by oxidation; The second superconducting strip is formed on the substrate by oblique evaporation from one end away from the first trench to the other end, with its end face facing the first superconducting strip and in contact with the insulating layer in a direction parallel to the surface of the substrate, thereby forming a Josephson junction.

2. The manufacturing method according to claim 1, characterized in that, Before the mask is set or formed, the manufacturing method further includes: Grooves are etched into the surface of the substrate; A third photoresist layer flush with the surface of the substrate is filled in the groove. The third photoresist layer uses a different photoresist than the first and second photoresist layers. After the mask is set or formed, in the area where the first trench and the second trench are not connected, the area within a preset distance from the first trench is located above the groove, and the first trench and the second trench at least partially expose the substrate; After the second superconducting strip is formed, the manufacturing method further includes: Remove the mask and the third photoresist layer to suspend the Josephson junction above the groove.

3. The manufacturing method according to claim 1, characterized in that, There are two second grooves and two fourth grooves, with each second groove corresponding to one of the two fourth grooves, and the two second grooves located on the same side of the first groove.

4. The manufacturing method according to claim 1, characterized in that, The cross-sectional shape and opening shape of the first groove, the second groove, the third groove and the fourth groove are all rectangular.

5. The manufacturing method according to claim 1, characterized in that, The openings of the first groove and the third groove coincide, and the openings of the second groove and the fourth groove coincide in a direction perpendicular to the extension direction.

6. The manufacturing method according to claim 1, characterized in that, The process of forming mutually perpendicular but non-connected first and second trenches on the first photoresist layer by photolithography, and forming mutually perpendicular and connected third and fourth trenches on the second photoresist layer, includes: A first strip region, a second strip region perpendicular to the first strip region, and an intermediate region connecting the first strip region and the second strip region are defined on the first photoresist layer. The first and second photoresist layers of the first and second strip regions are exposed, as is the second photoresist layer of the intermediate region; The first photoresist layer of the first strip region and the second strip region is removed by development, and a first trench and a second trench that are perpendicular to each other but not connected are formed on the first photoresist layer. The second photoresist layer of the first strip region, the second strip region and the intermediate region are removed, and a third trench and a fourth trench that are perpendicular to each other and connected are formed on the second photoresist layer.

7. A Josephson junction device obtained by a method of manufacturing a Josephson junction device according to any one of claims 1 to 6.

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