Superconducting quantum chip and manufacturing method thereof

Abstract

The invention provides a superconducting quantum chip and a manufacturing method thereof, and relates to the technical field of quantum information, a first superconducting layer and a second superconducting layer in a superconducting structure are communicated by adopting an air bridge, the potential difference and the slot line mode between the first superconducting layer and the second superconducting layer are further eliminated, and the performance of the superconducting quantum chip is improved. The bridge deck width of the bridge deck part provided by the invention is optimally designed, that is, the bridge deck width of the bridge deck part is designed to be gradually reduced in the direction from the joint of the bridge deck part and the first bridge pier part and the joint of the bridge deck part and the second bridge pier part to the middle area of the bridge deck part; according to the invention, the stray capacitance between the air bridge and the superconducting transmission line is reduced, the influence of the stray capacitance on the superconducting quantum chip is improved, the performance of the superconducting quantum chip is further improved, the strength and stability of the bridge surface part are improved, the probability of collapse of the air bridge is reduced, the manufacturing difficulty of the bridge surface part of the air bridge is reduced, and the manufacturing cost is reduced. And the manufacturing process of the air bridge is simplified.

Description

Technical Field

[0001] The present invention relates to the field of quantum information technology, and more specifically, to a superconducting quantum chip and a method for manufacturing the same. Background Art

[0002] Similar to classical chips, superconducting quantum chips are the physical carriers of superconducting quantum computing. Multiple superconducting qubits are typically integrated on the chip, with quantum information encoded in the qubits, and specific quantum tasks are achieved by manipulating the qubits. The superconducting qubit circuit reading cavity and control lines are both coplanar waveguide (CPW) structures. However, due to the plane disruption caused by the coplanar waveguide structure and the asymmetric effect of the chip's overall structure, when a signal is input into the qubit chip, a potential difference is generated between the ground wires on both sides of the coplanar waveguide structure's transmission line, thereby exciting the generation of parasitic slotline modes, which in turn affect the coherence of the qubit. To address this issue and increase the decoherence time of the qubit, the two ground wires of the coplanar waveguide structure need to be connected to eliminate the potential difference and the slotline mode.

[0003] An air bridge is a structure formed using a specific process that connects two interconnected lines. Because it doesn't introduce additional dielectric material onto the chip, it's less likely to introduce decoherence issues. It's often used to connect ground lines in coplanar waveguide structures. However, using an air bridge to connect two ground lines in a coplanar waveguide structure introduces new problems, leading to performance degradation in superconducting quantum chips. Summary of the Invention

[0004] In view of this, the present invention provides a superconducting quantum chip and a method for manufacturing the same, which effectively solves the technical problems existing in the prior art and improves the performance of the superconducting quantum chip.

[0005] To achieve the above objectives, the present invention provides the following technical solutions:

[0006] A superconducting quantum chip, comprising:

[0007] a substrate comprising a first surface;

[0008] a superconducting structure, the superconducting structure comprising a first superconducting layer, a superconducting transmission line, and a second superconducting layer sequentially spaced on the first surface along a first direction;

[0009] An air bridge includes a first bridge pier portion connected to the first superconducting layer, a second bridge pier portion connected to the second superconducting layer, and a bridge portion portion spanning the superconducting transmission line and connecting the first bridge pier portion and the second bridge pier portion, wherein the bridge deck width of the bridge portion portion gradually decreases from the connection between the bridge portion portion and the first bridge pier portion and the connection between the bridge portion portion and the second bridge pier portion toward the middle area of ​​the bridge portion portion.

[0010] Optionally, the superconducting structure is a coplanar waveguide structure.

[0011] Optionally, the material of the superconducting structure is niobium, aluminum or tantalum.

[0012] Optionally, in the extension direction of the superconducting transmission line, an edge line of at least one side of a vertical projection of the bridge portion on the first surface is in an arc shape that is concave toward the inside of the bridge portion.

[0013] Optionally, in a direction perpendicular to the first surface, a middle region of the bridge portion and the superconducting transmission line have an overlapping region.

[0014] Optionally, in a direction perpendicular to the first surface, a minimum bridge deck width of an overlapping area between the bridge surface portion and the superconducting transmission line is not less than 4 microns.

[0015] Optionally, the material of the air bridge is aluminum or copper;

[0016] The thickness of the air bridge is not less than 200 nanometers.

[0017] Optionally, the bridge face portion is an arched bridge face portion;

[0018] Alternatively, the bridge surface comprises a first edge bridge deck, a middle bridge deck, and a second edge bridge deck sequentially divided along the first direction, and the first edge bridge deck and the second edge bridge deck each form an angle at a connection with the middle bridge deck;

[0019] Alternatively, the bridge surface portion includes a first sub-bridge deck and a second sub-bridge deck sequentially divided along the first direction, and a connection between the first sub-bridge deck and the second sub-bridge deck has an angle.

[0020] Based on the same inventive concept, the present invention also provides a method for manufacturing a superconducting quantum chip, which is used to manufacture the above-mentioned superconducting quantum chip. The manufacturing method includes:

[0021] providing a substrate comprising a first surface;

[0022] forming a superconducting structure on the first surface, the superconducting structure comprising a first superconducting layer, a superconducting transmission line, and a second superconducting layer sequentially spaced apart along a first direction;

[0023] forming a first photoresist layer on the superconducting structure, wherein the first photoresist layer includes a first bridge pier hollowing out and a second bridge pier hollowing out, wherein the first bridge pier hollowing out exposes the first superconducting layer, and the second bridge pier hollowing out exposes the second superconducting layer;

[0024] Depositing a conductive layer on the first photoresist layer, wherein the conductive layer fills the first bridge pier hollow and the second bridge pier hollow;

[0025] Etching the conductive layer to form an air bridge, the air bridge comprising a first bridge pier portion connected to the first superconducting layer, a second bridge pier portion connected to the second superconducting layer, and a bridge portion portion spanning the superconducting transmission line and connecting the first bridge pier portion and the second bridge pier portion, wherein the bridge portion portion has a bridge width gradually decreasing from a connection point between the bridge portion portion and the first bridge pier portion and a connection point between the bridge portion portion and the second bridge pier portion toward a middle region of the bridge portion portion;

[0026] The first photoresist layer is removed.

[0027] Optionally, after forming a first photoresist layer on the superconducting structure and before evaporating a conductive layer on the first photoresist layer, the method further includes:

[0028] The first photoresist layer is baked to flow, and the first photoresist layer forms an arch in the area between the first bridge pier hollow and the second bridge pier hollow. When the conductive layer is etched to form an air bridge, the bridge surface is an arched bridge surface.

[0029] Compared with the prior art, the technical solution provided by the present invention has at least the following advantages:

[0030] The present invention provides a superconducting quantum chip and a method for manufacturing the same, comprising: a substrate, the substrate comprising a first surface; a superconducting structure, the superconducting structure comprising a first superconducting layer, a superconducting transmission line, and a second superconducting layer sequentially spaced along a first direction on the first surface; an air bridge, the air bridge comprising a first pier portion connected to the first superconducting layer, a second pier portion connected to the second superconducting layer, and a bridge portion portion spanning the superconducting transmission line and connecting the first pier portion and the second pier portion, wherein the bridge deck width of the bridge portion portion gradually decreases from the connection between the bridge portion portion and the first pier portion and the connection between the bridge portion portion and the second pier portion in a direction toward a middle area of ​​the bridge portion portion.

[0031] As can be seen from the foregoing, the technical solution provided by the present invention utilizes an air bridge to connect the first and second superconducting layers in the superconducting structure, thereby eliminating the potential difference and slot-line pattern between the first and second superconducting layers, thereby improving the performance of the superconducting quantum chip. Furthermore, the bridge section provided by the present invention features an optimized design of the bridge deck width, which gradually decreases from its connection with the first and second pier sections toward the middle region of the bridge section. This not only reduces the parasitic capacitance between the air bridge and the superconducting transmission line, thus alleviating the impact of the parasitic capacitance on the superconducting quantum chip and further improving the performance of the superconducting quantum chip, but also enhances the strength and stability of the bridge section, reduces the probability of air bridge collapse, and simplifies the fabrication process of the air bridge section. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0033] Figure 1 A schematic diagram of the structure of a superconducting quantum chip provided by an embodiment of the present invention;

[0034] Figure 2 for Figure 1 Section along AA' direction;

[0035] Figure 3 A flowchart of a method for manufacturing a superconducting quantum chip provided by an embodiment of the present invention;

[0036] Figures 4a to 4f for Figure 3 Schematic diagram of the structure corresponding to each step;

[0037] Figure 5 A schematic diagram of the structure of another superconducting quantum chip provided by an embodiment of the present invention;

[0038] Figure 6 A schematic structural diagram of another superconducting quantum chip provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0039] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0040] As described in the background art, the reading cavity and control line of the superconducting quantum bit circuit are both coplanar waveguide structures. However, due to the disruption of the plane by the coplanar waveguide structure and the asymmetric effect of the overall chip structure, when the quantum bit chip is fed with a signal, a potential difference is generated between the ground lines on both sides of the transmission line of the coplanar waveguide structure, thereby exciting the generation of parasitic slot line modes and then affecting the coherence of the quantum bit. In order to solve this problem and improve the decoherence time of the quantum bit, it is necessary to connect the two ground lines of the coplanar waveguide structure to eliminate the potential difference and the slot line mode. The air bridge is a bridging structure formed by a specific process, which connects the two lines that need to be connected. Because it does not introduce additional dielectric materials on the chip, it is not easy to cause additional decoherence problems. It is often used as a connection process for the ground lines in the coplanar waveguide structure. However, the inventors found that using an air bridge to connect the two ground lines of the coplanar waveguide structure introduces new problems. For example, due to the technical problem of parasitic capacitance caused by the overlap of the air bridge and the transmission line, and due to the large number of air bridges, the parasitic coupling caused cannot be ignored, which leads to the performance degradation of the superconducting quantum chip.

[0041] Based on this, the embodiments of the present invention provide a superconducting quantum chip and a method for manufacturing the same, which effectively solve the technical problems existing in the prior art and improve the performance of the superconducting quantum chip.

[0042] To achieve the above purpose, the technical solution provided by the embodiment of the present invention is as follows, specifically combined with Figures 1 to 6 The technical solution provided by the embodiment of the present invention is described in detail.

[0043] Combine Figure 1 and Figure 2 As shown, Figure 1 A schematic diagram of the structure of a superconducting quantum chip provided by an embodiment of the present invention is shown in FIG. Figure 2 for Figure 1 The superconducting quantum chip provided by the embodiment of the present invention includes:

[0044] The substrate 100 includes a first surface.

[0045] The superconducting structure includes a first superconducting layer 210, a superconducting transmission line 230, and a second superconducting layer 220 sequentially arranged on the first surface along a first direction X.

[0046] An air bridge includes a first pier portion 310 connected to the first superconducting layer 210, a second pier portion 320 connected to the second superconducting layer 220, and a bridge portion 330 spanning the superconducting transmission line 230 and connecting the first pier portion 210 and the second pier portion 220. The bridge portion 330 has a deck width that gradually decreases from the connection between the bridge portion 330 and the first pier portion 310 and the second pier portion 320 toward a middle region of the bridge portion 330. Assuming that the minimum deck width of the middle region of the bridge portion 330 is d1, in a direction X1 from the first pier portion 310 toward the middle region of the bridge portion 330, the deck width d1 is smaller than the deck width d2 of a portion of the bridge portion 330 in the direction X1; and in a direction X2 from the second pier portion 320 toward the middle region of the bridge portion 330, the deck width d1 is smaller than the deck width d3 of a portion of the bridge portion 330 in the direction X2.

[0047] The bridge section 330 provided in this embodiment of the present invention spans the superconducting transmission line, meaning that the bridge section 330 and the superconducting transmission line 230 have an overlapping region in a direction Z perpendicular to the first surface. Furthermore, the bridge section 330 has a width corresponding to the width of the bridge section 330 along the extension direction Y of the superconducting transmission line 230. Optionally, the bridge section 330's width at the junction of the first pier 310 and the bridge section 330 is the same as the width at the junction of the second pier 320 and the bridge section 330, although this is not specifically limited in this invention.

[0048] As can be understood, the technical solution provided by the embodiments of the present invention utilizes an air bridge to connect the first and second superconducting layers in the superconducting structure, thereby eliminating the potential difference and slot-line pattern between the first and second superconducting layers, thereby improving the performance of the superconducting quantum chip. Furthermore, the bridge surface width provided by the embodiments of the present invention is optimized, namely, the bridge surface width is designed to gradually decrease from the connection between the bridge surface and the first pier portion and the connection with the second pier portion toward the middle area of ​​the bridge surface. This not only reduces the overlap area between the air bridge and the superconducting transmission line, thereby reducing the parasitic capacitance between the two and ameliorating the impact of parasitic capacitance on the superconducting quantum chip, further improving the performance of the superconducting quantum chip, but also enhances the strength and stability of the bridge surface, reduces the probability of air bridge collapse, and simultaneously reduces the difficulty of manufacturing the air bridge surface, simplifying the air bridge manufacturing process.

[0049] Based on the same inventive concept, an embodiment of the present invention further provides a method for manufacturing a superconducting quantum chip, which is used to manufacture the superconducting quantum chip provided by any embodiment. Figure 3FIG. 1 is a flow chart of a method for manufacturing a superconducting quantum chip according to an embodiment of the present invention, wherein the manufacturing method includes:

[0050] S1. Provide a substrate, wherein the substrate includes a first surface.

[0051] S2. Form a superconducting structure on the first surface, wherein the superconducting structure includes a first superconducting layer, a superconducting transmission line, and a second superconducting layer that are sequentially spaced along a first direction.

[0052] S3. Form a first photoresist layer on the superconducting structure, wherein the first photoresist layer includes a first bridge pier hollowing out and a second bridge pier hollowing out, wherein the first bridge pier hollowing out exposes the first superconducting layer, and the second bridge pier hollowing out exposes the second superconducting layer.

[0053] S4. Evaporating a conductive layer on the first photoresist layer, and filling the first bridge pier hollow and the second bridge pier hollow with the conductive layer.

[0054] S5. Etch the conductive layer to form an air bridge, wherein the air bridge includes a first pier portion connected to the first superconducting layer, a second pier portion connected to the second superconducting layer, and a bridge portion portion spanning the superconducting transmission line and connecting the first pier portion and the second pier portion, wherein the bridge width of the bridge portion portion gradually decreases from the connection between the bridge portion portion and the first pier portion and the connection between the bridge portion portion and the second pier portion toward the middle area of ​​the bridge portion portion.

[0055] S6. Remove the first photoresist layer.

[0056] The following combination Figures 4a to 4f The technical solution provided by the embodiment of the present invention is described in more detail. Figures 4a to 4f for Figure 3 Schematic diagram of the corresponding structure of each step.

[0057] like Figure 4a As shown, corresponding to step S1 , a substrate 100 is provided, and the substrate 100 includes a first surface.

[0058] like Figure 4b As shown, corresponding to step S2, a superconducting structure is formed on the first surface, and the superconducting structure includes a first superconducting layer 210, a superconducting transmission line 220 and a second superconducting layer 230 which are sequentially arranged along the first direction X.

[0059] In one embodiment of the present invention, the superconducting structure provided by this embodiment is a coplanar waveguide structure, i.e., both the first superconducting layer and the second superconducting layer are ground layers. Optionally, the material of the superconducting structure provided by this embodiment of the present invention may be niobium, aluminum, or tantalum, which is not specifically limited to this invention. Other superconducting materials may also be used in other embodiments of the present invention.

[0060] The superconducting structure provided by the embodiments of the present invention can be formed using a photolithography process, specifically comprising: forming a superconducting material layer on a substrate; then forming a photoresist layer on the superconducting material layer; exposing and developing the photoresist layer to form a hollow pattern; etching the superconducting material layer using the photoresist layer as a mask, and then removing the photoresist layer to form the superconducting structure. The superconducting material layer can be etched using a wet etching process, with the wet etching solution being determined by the material of the superconducting structure. For example, if the superconducting structure is made of niobium, a niobium etchant is used; if the superconducting structure is made of aluminum, an aluminum etchant is used; if the superconducting structure is made of tantalum, a tantalum etchant is used, and so on.

[0061] like Figure 4c As shown, corresponding to step S3 , a first photoresist layer 400 is formed on the superconducting structure. The first photoresist layer 400 includes a first bridge pier hollow 410 and a second bridge pier hollow 420 . The first bridge pier hollow 410 exposes the first superconducting layer 210 , and the second bridge pier hollow 420 exposes the second superconducting layer 220 .

[0062] In one embodiment of the present invention, the first photoresist layer provided in the embodiment of the present invention can be one of the photoresists such as SPR22 series, S1805, etc.; and the photolithography machine used to expose the photoresist layer can be one of MA6, laser direct writing, Stepper stepping photolithography machine, etc.

[0063] In order to improve the strength and stability of the air bridge and reduce the risk of collapse of the air bridge, the bridge surface of the air bridge can be made into an arched bridge surface. Therefore, after forming the first photoresist layer, the first photoresist layer can be optimized so that the side of the first photoresist layer facing away from the substrate is in an outward convex arc shape, such as Figure 4c The first photoresist layer 400 is shown as having an arched shape on a side facing away from the substrate 100. Optionally, after forming the first photoresist layer on the superconducting structure and before evaporating a conductive layer on the first photoresist layer, the method further includes: baking the first photoresist layer to make it flow, so that the first photoresist layer forms an arched shape in the area between the first bridge pier hollow and the second bridge pier hollow. When etching the conductive layer to form the air bridge, the bridge surface is an arched bridge surface.

[0064] Specifically, after the first photoresist layer is exposed and developed to form the first bridge pier hollow and the second bridge pier hollow, the substrate structure formed with the first photoresist layer is baked on a hot plate at 140-160 degrees Celsius for 3-5 minutes to allow the photoresist to flow fully, and finally form an arch in the area between the first bridge pier hollow and the second bridge pier hollow.

[0065] like Figure 4dAs shown, corresponding to step S4 , a conductive layer 300 is evaporated on the first photoresist layer 400 , and the conductive layer 300 fills the first bridge pier hollow 410 and the second bridge pier hollow 420 .

[0066] In one embodiment of the present invention, the conductive layer provided in this embodiment of the present invention can be made of a metal or alloy material, that is, the air bridge can be a metal or alloy air bridge. Optionally, the conductive layer provided in this embodiment of the present invention can be made of aluminum or copper, that is, the air bridge can be made of aluminum or copper; and the conductive layer can be no less than 200 nanometers thick, that is, the air bridge can be no less than 200 nanometers thick.

[0067] like Figure 4e As shown, corresponding to step S5, the conductive layer is etched to form an air bridge, wherein the air bridge includes a first pier portion 310 connected to the first superconducting layer 210, a second pier portion 320 connected to the second superconducting layer 220, and a bridge portion 330 spanning the superconducting transmission line 230 and connecting the first pier portion 210 and the second pier portion 220, wherein the bridge portion 330 has a bridge width gradually reduced from the connection between the bridge portion 330 and the first pier portion 310 and the connection between the bridge portion 330 and the second pier portion 320 toward the middle area of ​​the bridge portion 330.

[0068] It is understood that the first pier portion is the portion of the first pier hollowed out by the conductive layer, and the second pier portion is the portion of the second pier hollowed out by the conductive layer. Furthermore, embodiments of the present invention do not impose any specific restrictions on the shape of the bridge portion formed by etching the conductive layer, as long as the bridge portion has a gradually decreasing width from its connection with the first pier portion and its connection with the second pier portion toward the middle of the bridge portion; that is, the bridge portion has a gradually decreasing width from the two ends of the pier portion toward the middle of the bridge portion.

[0069] The air bridge provided by the embodiments of the present invention can be formed using a photolithography process. Specifically, a photoresist layer is formed on the conductive layer, and the photoresist layer is exposed and developed to form a pattern covering the air bridge. The conductive layer is then etched using the photoresist layer as a mask to form the air bridge. Optionally, the conductive layer can be etched using a wet etching method. The wet etching solution depends on the material of the conductive layer. For example, when the conductive layer is made of copper, a copper etchant is used to etch the conductive layer; when the conductive layer is made of aluminum, an aluminum etchant is used to etch the conductive layer, and so on.

[0070] In one embodiment of the present invention, in the extension direction of the superconducting transmission line, the edge line of at least one side of the vertical projection of the bridge portion on the first surface is in an arc shape concave toward the inside of the bridge portion. Figure 4eAs shown in the top view, the two sides of the bridge surface 330 are in the shape of an inwardly concave arc, thereby improving the strength and stability of the air bridge. Figure 4e As shown, in the vertical projection of the bridge portion 330 on the first surface, the line in the extension direction of the superconducting transmission line where the midpoint of the bridge portion 330 is located is the axis (as shown in FIG. Figure 4e The axis Y1 in the middle is symmetrical in shape, which further improves the strength and stability of the air bridge.

[0071] In one embodiment of the present invention, in a direction perpendicular to the first surface, a middle region of the bridge face portion has an overlapping area with the superconducting transmission line; wherein, the bridge deck width of the middle region of the bridge face portion is the area with the smallest bridge deck width of the entire bridge face portion, and the superconducting transmission line is designed to be located in the portion corresponding to the middle region of the bridge face portion. On the basis of ensuring the strength and stability of the air bridge, the overlapping area between the superconducting transmission line and the bridge face portion is minimized to the greatest extent, thereby reducing the parasitic capacitance between the two and improving the performance of the superconducting quantum chip.

[0072] Furthermore, in a direction perpendicular to the first surface, the minimum bridge deck width of the overlapping area between the bridge portion and the superconducting transmission line provided by the embodiment of the present invention is not less than 4 microns, thereby avoiding the problem of the bridge deck width in the overlapping area between the bridge portion and the superconducting transmission line being too small, thereby reducing the strength and stability of the air bridge and reducing the risk of collapse of the air bridge.

[0073] like Figure 4f As shown, corresponding to step S6, the first photoresist layer is removed.

[0074] In one embodiment of the present invention, the bridge portion 330 provided in the embodiment of the present invention may be an arched bridge portion, such as Figure 4f shown.

[0075] Or refer to Figure 5 FIG. 1 is a schematic diagram of the structure of another superconducting quantum chip according to an embodiment of the present invention. The bridge surface portion according to the embodiment of the present invention includes a first edge bridge surface 331, a middle bridge surface 333, and a second edge bridge surface 332, which are sequentially divided along the first direction. The first edge bridge surface 331 and the second edge bridge surface 332 each have an angle a at their connection with the middle bridge surface 333. Optionally, the angle a at the connection between the first edge bridge surface 331 and the second edge bridge surface 332 and the middle bridge surface 333 can be a right angle or an obtuse angle, which is not specifically limited by the present invention.

[0076] Or refer to Figure 6, which is a schematic structural diagram of another superconducting quantum chip provided by an embodiment of the present invention, wherein the bridge surface portion provided by this embodiment of the present invention includes a first sub-bridge surface 334 and a second sub-bridge surface 335 sequentially divided along the first direction, and the connection between the first sub-bridge surface 334 and the second sub-bridge surface 335 forms an angle b. Optionally, the angle b formed between the first sub-bridge surface 334 and the second sub-bridge surface 335 can be an acute angle, a right angle, or an obtuse angle, which is not specifically limited by the present invention.

[0077] It should be noted that the shape of the bridge portion provided by the present invention is not limited to the several shapes provided in the above embodiments. In other embodiments of the present invention, the bridge portion may also be in other shapes, which needs to be specifically designed according to actual applications.

[0078] An embodiment of the present invention provides a superconducting quantum chip and a method for manufacturing the same, comprising: a substrate, the substrate comprising a first surface; a superconducting structure, the superconducting structure comprising a first superconducting layer, a superconducting transmission line, and a second superconducting layer sequentially spaced along a first direction on the first surface; an air bridge, the air bridge comprising a first pier portion connected to the first superconducting layer, a second pier portion connected to the second superconducting layer, and a bridge portion portion spanning the superconducting transmission line and connecting the first pier portion and the second pier portion, wherein the bridge deck width of the bridge portion portion gradually decreases from the connection between the bridge portion portion and the first pier portion and the connection between the bridge portion portion and the second pier portion in a direction toward the middle area of ​​the bridge portion portion.

[0079] As can be seen from the foregoing, the technical solution provided by the embodiments of the present invention utilizes an air bridge to connect the first and second superconducting layers in the superconducting structure, thereby eliminating the potential difference and slot-line pattern between the first and second superconducting layers, thereby improving the performance of the superconducting quantum chip. Furthermore, the bridge section provided by the embodiments of the present invention features an optimized design of the bridge deck width, which gradually decreases from its connection with the first and second pier sections toward the middle region of the bridge section. This not only reduces the parasitic capacitance between the air bridge and the superconducting transmission line, thus alleviating the impact of the parasitic capacitance on the superconducting quantum chip and further improving the performance of the superconducting quantum chip, but also enhances the strength and stability of the bridge section, reduces the probability of air bridge collapse, and simplifies the fabrication process of the air bridge section.

[0080] In the description of the present invention, it should be understood that the orientations or positional relationships indicated by terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", and "circumferential" are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the present invention.

[0081] 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 the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0082] In the present invention, unless otherwise specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections, electrical connections, or communication between them; direct connections or indirect connections through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0083] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0084] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0085] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A superconducting quantum chip, characterized in that: include: a substrate comprising a first surface; a superconducting structure, the superconducting structure comprising a first superconducting layer, a superconducting transmission line, and a second superconducting layer sequentially spaced on the first surface along a first direction; An air bridge includes a first bridge pier portion connected to the first superconducting layer, a second bridge pier portion connected to the second superconducting layer, and a bridge portion portion spanning the superconducting transmission line and connecting the first bridge pier portion and the second bridge pier portion, wherein the bridge deck width of the bridge portion portion gradually decreases from the connection between the bridge portion portion and the first bridge pier portion and the connection between the bridge portion portion and the second bridge pier portion toward the middle area of ​​the bridge portion portion.

2. The superconducting quantum chip according to claim 1, characterized in that The superconducting structure is a coplanar waveguide structure.

3. The superconducting quantum chip according to claim 1, characterized in that The material of the superconducting structure is niobium, aluminum or tantalum.

4. The superconducting quantum chip according to claim 1, characterized in that In the extending direction of the superconducting transmission line, an edge line of at least one side of a vertical projection of the bridge portion on the first surface is in an arc shape that is concave toward the inside of the bridge portion.

5. The superconducting quantum chip according to claim 1, characterized in that In a direction perpendicular to the first surface, a middle region of the bridge portion and the superconducting transmission line have an overlapping region.

6. The superconducting quantum chip according to claim 1, characterized in that In a direction perpendicular to the first surface, a minimum bridge surface width of an overlapping region between the bridge surface portion and the superconducting transmission line is not less than 4 micrometers.

7. The superconducting quantum chip according to claim 1, characterized in that The material of the air bridge is aluminum or copper; The thickness of the air bridge is not less than 200 nanometers.

8. The superconducting quantum chip according to claim 1, characterized in that: The bridge surface is an arched bridge surface; Alternatively, the bridge surface comprises a first edge bridge deck, a middle bridge deck, and a second edge bridge deck sequentially divided along the first direction, and the first edge bridge deck and the second edge bridge deck each form an angle at a connection with the middle bridge deck; Alternatively, the bridge surface portion includes a first sub-bridge deck and a second sub-bridge deck sequentially divided along the first direction, and a connection between the first sub-bridge deck and the second sub-bridge deck has an angle.

9. A method for manufacturing a superconducting quantum chip, characterized in that: For manufacturing the superconducting quantum chip according to any one of claims 1 to 8, the manufacturing method comprises: providing a substrate comprising a first surface; forming a superconducting structure on the first surface, the superconducting structure comprising a first superconducting layer, a superconducting transmission line, and a second superconducting layer sequentially spaced apart along a first direction; forming a first photoresist layer on the superconducting structure, wherein the first photoresist layer includes a first bridge pier hollowing out and a second bridge pier hollowing out, wherein the first bridge pier hollowing out exposes the first superconducting layer, and the second bridge pier hollowing out exposes the second superconducting layer; Depositing a conductive layer on the first photoresist layer, wherein the conductive layer fills the first bridge pier hollow and the second bridge pier hollow; Etching the conductive layer to form an air bridge, the air bridge comprising a first bridge pier portion connected to the first superconducting layer, a second bridge pier portion connected to the second superconducting layer, and a bridge portion portion spanning the superconducting transmission line and connecting the first bridge pier portion and the second bridge pier portion, wherein the bridge portion portion has a bridge width gradually decreasing from a connection point between the bridge portion portion and the first bridge pier portion and a connection point between the bridge portion portion and the second bridge pier portion toward a middle region of the bridge portion portion; The first photoresist layer is removed.

10. The method for manufacturing a superconducting quantum chip according to claim 9, characterized in that: After forming a first photoresist layer on the superconducting structure and before evaporating a conductive layer on the first photoresist layer, the method further includes: The first photoresist layer is baked to flow, and the first photoresist layer forms an arch in the area between the first bridge pier hollow and the second bridge pier hollow. When the conductive layer is etched to form an air bridge, the bridge surface is an arched bridge surface.

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