Quantum device intermediate, method for manufacturing quantum device, and method for manufacturing quantum device intermediate

Abstract

To provide a quantum device intermediate capable of reducing adhesion of an organic substance to a quantum bit circuit, and to provide a quantum device manufacturing method and a method of manufacturing the quantum device intermediate.SOLUTION: The quantum device intermediate includes a mask layer including a first sacrificial layer and a second sacrificial layer on a superconductor layer. Further, focusing on the mask layer, the content of the organic material in the first sacrificial layer is smaller than the content of the organic material in the second sacrificial layer.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The present disclosure relates to a quantum device intermediate, a quantum device manufacturing method, and a method for manufacturing a quantum device intermediate. [Background technology]

[0002] Quantum devices including quantum bit circuits are known, and it is known that such quantum devices use Josephson junctions in the quantum bit circuits.

[0003] For example, Patent Document 1 describes a method for manufacturing a Josephson junction device, comprising the steps of: forming a mask layer on a substrate, the mask layer including a plurality of mask patterns arranged in a first direction, each mask pattern having a first opening extending in a first direction and a second opening extending in a second direction intersecting the first direction and intersecting the first opening; forming a first film on the substrate by a first film deposition from obliquely above in the first direction using the mask layer as a mask, and then forming a second film on the substrate by a second film deposition from obliquely above in a direction different from the first film deposition, thereby forming a first superconducting film including the first film and the second film; forming an insulating film on a surface of the first superconducting film; and forming a third film on the substrate by a third film deposition from obliquely above in the second direction using the mask layer as a mask, the third film having a region overlapping the first superconducting film via the insulating film, thereby forming a second superconducting film including the third film. The mask layer is formed of two layers of resist. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2023 / 243080 Summary of the Invention [Problem to be solved by the invention]

[0005] In a quantum bit circuit including a Josephson junction device manufactured by the method described in Patent Document 1, organic resist residue may adhere to the quantum bit circuit. If organic matter adheres to the quantum bit circuit, the probability of undesirable quantum bit decoherence occurring may increase depending on the amount of organic matter.

[0006] An object of the present disclosure is to provide a quantum device intermediate, a quantum device manufacturing method, and a quantum device intermediate manufacturing method that solve the above-mentioned problems. [Means for solving the problem]

[0007] The quantum device intermediate of the present disclosure comprises a substrate, a superconductor layer stacked on the substrate, a first sacrificial layer stacked on the superconductor layer, and a second sacrificial layer stacked on the first sacrificial layer, wherein the organic material content in the first sacrificial layer is smaller than the organic material content in the second sacrificial layer.

[0008] The quantum device manufacturing method disclosed herein includes a quantum device intermediate including a substrate, a superconductor layer stacked on the substrate, a first sacrificial layer stacked on the superconductor layer, and a second sacrificial layer stacked on the first sacrificial layer, wherein the first sacrificial layer has a lower organic material content than the second sacrificial layer, and includes the steps of: forming an opening in the second sacrificial layer with a beam; removing the first sacrificial layer through the opening; stacking a first vapor deposition pattern on the superconductor layer and the substrate; oxidizing a surface of the first vapor deposition pattern; and stacking a second vapor deposition pattern at a position laterally shifted from the first vapor deposition pattern so as to partially overlap the first vapor deposition pattern.

[0009] The method for manufacturing a quantum device intermediate of the present disclosure includes the steps of stacking a superconductor layer on a substrate, stacking a first sacrificial layer on the superconductor layer, and stacking a second sacrificial layer on the first sacrificial layer, wherein the content of organic material in the first sacrificial layer is smaller than the content of organic material in the second sacrificial layer. [Effects of the Invention]

[0010] According to the quantum device intermediate, quantum device manufacturing method, and quantum device intermediate manufacturing method of the present disclosure, adhesion of organic matter to a quantum bit circuit can be reduced. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view I showing an example of the configuration of a quantum device intermediate according to the present disclosure. [Figure 2] 2 is a cross-sectional view II showing an example of the configuration of a quantum device intermediate according to the present disclosure. [Figure 3] FIG. 1 is a plan view showing an example of the configuration of a quantum device intermediate according to the present disclosure. [Figure 4] 3 is a cross-sectional view III showing an example of the configuration of a quantum device intermediate according to the present disclosure. [Figure 5] 1 is a flowchart I showing an example of a process for manufacturing a quantum device intermediate according to the present disclosure. [Figure 6] 1 is a flowchart I showing an example of processing in a quantum device manufacturing method according to the present disclosure. [Figure 7] FIG. 10 is a supplementary diagram I showing an example of a process of a quantum device manufacturing method according to the present disclosure. [Figure 8] FIG. 10 is a supplementary diagram showing an example of processing in a quantum device manufacturing method according to a modified example. [Figure 9] FIG. 1 is a perspective view illustrating an example of the configuration of a quantum device intermediate according to the present disclosure. [Figure 10] FIG. 2 is a supplementary diagram II showing an example of a process of a quantum device manufacturing method according to the present disclosure. [Figure 11] 4 is a cross-sectional view IV showing an example of the configuration of a quantum device intermediate according to the present disclosure. [Figure 12] 10 is a flowchart II showing an example of a process for manufacturing a quantum device intermediate according to the present disclosure. [Figure 13] 10 is a flowchart II showing an example of processing in a quantum device manufacturing method according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, examples of each embodiment according to the present disclosure will be described using the drawings. Note that the drawings and specific configurations used in each embodiment should not be used to interpret the disclosure. The same or corresponding configurations in all drawings will be assigned the same reference numerals, and common descriptions will be omitted. It should be noted that in this disclosure, the drawings may relate to one or more embodiments.

[0013] First Embodiment Hereinafter, an embodiment according to the present disclosure will be described with reference to the drawings. First, an example of a quantum device intermediate according to the present disclosure will be described with reference to FIGS.

[0014] Hereinafter, the direction in which each pattern is stacked will be referred to as the Z direction. One direction within the substrate surface 11s, which will be described later, will be referred to as the X direction. The direction intersecting the X direction within the substrate surface 11s will be referred to as the Y direction. One side of the X direction will be referred to as the +X direction, and the other side of the X direction will be referred to as the -X direction. One side of the Y direction will be referred to as the +Y direction, and the other side of the Y direction will be referred to as the -Y direction. One side of the Z direction will be referred to as the +Z direction, and the other side of the Z direction will be referred to as the -Z direction. The direction from the -X direction to the +X direction will also be referred to as the deposition direction D1. Conversely, the direction from the +X direction to the -X direction will also be referred to as the deposition direction D1'. The Y direction will also be referred to as the deposition direction D2. The Z direction will also be referred to as the stacking direction D3.

[0015] For example, the X, Y, and Z directions may be perpendicular to one another. For example, the substrate surface 11s may be a surface along the XY plane and facing the +Z direction. For example, the +Z direction may be the upward direction.

[0016] Unless otherwise specified below, the shape and position of the first vapor deposition pattern are those when viewed from the Z direction. The same applies to the shape and position of the second vapor deposition pattern.

[0017] (Structure of quantum device intermediates) The quantum device intermediate 10 is used as a workpiece in manufacturing the quantum device 100 described below. 1, a quantum device intermediate 10 includes a substrate 11, a superconductor layer 12, a first sacrificial layer 13, and a second sacrificial layer 14. FIG. 1 is a cross-sectional view taken along the line F1-F1 in FIG.

[0018] (Board configuration) The substrate 11 has a substrate surface 11s. The substrate surface 11s has a portion where electrodes and the like included in the superconductor layer 12 are laminated, and a portion where the substrate surface 11s is exposed before the formation of the sacrificial layer because the electrodes and the like are not laminated. The electrodes and the like also include a wiring pattern, which will be described later. For example, the substrate 11 may be made of a material such as silicon, sapphire, a compound semiconductor, etc. The quantum device intermediate 10 of the present disclosure employs silicon. For example, the substrate 11 may be formed of a single crystal, a polycrystal, an amorphous material, or the like. For example, the substrate 11 may be a high-resistivity semiconductor substrate.

[0019] (Structure of the superconductor layer) The superconductor layer 12 is laminated on the substrate surface 11 s of the substrate 11 . The superconductor layer 12 includes electrodes and the like. For example, two electrodes constituting a quantum bit are patterned on the substrate surface 11s as the superconductor layer 12 before the Josephson junction (hereinafter also referred to as "JJ") 5 is formed. Note that a readout resonator, a ground plane, and the like may also be patterned on the substrate surface 11s. For example, each pattern of the superconductor layer 12 may be patterned by reactive ion etching, wet etching, or the like. The superconductor layer 12 may be patterned by, for example, sputtering, vapor deposition, CVD (Chemical Vapor Deposition), or the like. The electrodes are made of a superconductor (alternatively, superconducting) material, which is a material that exhibits superconducting properties below its superconducting critical temperature. The superconductor layer 12 has a first electrode portion 121F and a second electrode portion 121S spaced apart from the first electrode portion 121F in the first direction.

[0020] (Configuration of each electrode) The two electrodes (first electrode portion 121F, second electrode portion 121S) included in the superconductor layer 12 are made of titanium nitride, titanium niobium nitride, tantalum, or MoRe. When a cavity 13c (described later) is formed in the first sacrificial layer 13 using vapor-phase hydrogen fluoride (Vapor BHF), the surfaces of the electrodes made of these materials become clean. This eliminates the need for argon milling on the electrode surfaces, which is performed before aluminum deposition. The two electrodes (first electrode portion 121F, second electrode portion 121S) may be made of niobium or aluminum, and in that case, a material other than gaseous hydrogen fluoride may be used to form the cavity.

[0021] (Overview of quantum device intermediates) The quantum device intermediate 10 of the present disclosure includes a mask layer including a first sacrificial layer 13 and a second sacrificial layer 14. The first sacrificial layer 13, which is closer to the substrate surface 11s than the second sacrificial layer 14 and is in contact with the substrate surface 11s, the first electrode portion 121F, and the second electrode portion 121S, is mainly composed of an inorganic material, as will be described later. As will be described later, the first sacrificial layer 13 is removed. If the content of inorganic material in the first sacrificial layer 13 is greater than the content of inorganic material in the second sacrificial layer 14, it is possible to reduce the amount of material that remains on the substrate surface 11s or the surface of the superconductor layer 12 after the first sacrificial layer 13 is removed. Alternatively, a separate process for cleaning the surfaces may be unnecessary or may be simplified. Therefore, quantum device intermediate 10 of the present disclosure is characterized in that the content of organic material in first sacrificial layer 13 is smaller than the content of organic material in second sacrificial layer 14 . As shown in FIG. 2, the second sacrificial layer 14 may have at least one opening 14EX. For example, the second sacrificial layer 14 in the following disclosure is a second sacrificial layer 14A having a plurality of openings 14EX. In FIG. 2, the first sacrificial layer 13 is in communication with the openings 14EX. FIG. 3 is a plan view of the quantum device intermediate 10A as viewed from the stacking direction D3. In the second sacrificial layer 14, bridges BR are present between the plurality of openings 14EX. The dimensions of the bridges BR in the deposition direction D1 (or deposition direction D1') are smaller than the dimensions of the openings 14EX in the same direction. For example, the dimensions of the bridges BR in the deposition direction D1 (or deposition direction D1') are approximately 1 / 4 to 1 / 2 of the dimensions of the openings 14EX in the same direction. Setting the dimensions of the bridges BR in this manner facilitates stacking of the first deposition layer 2 and the second deposition layer 4 by oblique deposition. As shown in FIG. 4, the first sacrificial layer 13 may be a first sacrificial layer 13A having a cavity 13c.

[0022] (Configuration of the first sacrificial layer) The first sacrificial layer 13 (first sacrificial layer 13A) is laminated on the superconductor layer 12. The first sacrificial layer 13 (first sacrificial layer 13A) is mainly composed of silicon oxide or silicon nitride. The proportion of silicon oxide and / or silicon nitride contained in the first sacrificial layer 13 is preferably 90% or more, more preferably 99% or more, and even more preferably 99.9% or more, in mass percent. Methods for forming the first sacrificial layer 13 include plasma enhanced chemical vapor deposition (PECVD) and chemical vapor deposition (CVD).

[0023] In FIG. 4, the first sacrificial layer 13A has a cavity 13c. The cavity 13c is an opening that encompasses at least one of the shapes of the openings 14EX when viewed from the stacking direction D3. In other words, the dimension of the cavity 13c in the X direction is larger than the dimension of the opening 14EX in the same direction. The opening shape of the cavity 13c is also referred to as an undercut shape, and the process for creating the undercut shape is also referred to as undercut processing. The cavity 13c is in communication with the opening 14EX. The cavity 13c is provided in the first sacrificial layer 13A by removing a part of the first sacrificial layer 13A with the gaseous hydrogen fluoride that has passed through the opening 14EX.

[0024] Instead of reactive treatment using gaseous hydrogen fluoride, reactive ion etching may be used. The reactive ion etching may be either isotropic or anisotropic. However, isotropic etching is more likely to produce an undercut shape than anisotropic etching.

[0025] (Second Sacrificial Layer) The second sacrificial layer 14 (second sacrificial layer 14A) is laminated on the first sacrificial layer 13. The second sacrificial layer 14 (second sacrificial layer 14A) includes an organic polymer. Examples of the organic polymer include polymethyl methacrylate (PMMA) and polymethyl glutamate (PMGI). The second sacrificial layer 14 (second sacrificial layer 14A) may include a monomer. For example, a method of spin-coating a resist for EB (Electron Beam: EB) exposure is one method for forming the second sacrificial layer 14. In this case, the above-mentioned materials are preferable as the resist material. In the step of forming the cavity 13c in the first sacrificial layer 13, it is necessary to prevent the second sacrificial layer 14 from being etched as much as possible and to maintain its shape. In this regard, organic materials such as organic polymers are preferred because they have high resistance to hydrogen fluoride and ion etching used in the step of forming the cavity 13c.

[0026] 2 again, the second sacrificial layer 14A has a plurality of openings 14EX. The openings 14EX are formed on the second sacrificial layer 14A by development with a developer after being patterned on the second sacrificial layer 14 by an EB exposure device.

[0027] (Differences in aperture shape due to film formation method of Josephson junction) For example, using two mask layers (layers including the first sacrificial layer 13 and the second sacrificial layer 14), the manufacturer deposits a Josephson junction by a method such as the Dolan Bridge method or the Manhattan method. Therefore, the shape of the opening in the second sacrificial layer 14 varies depending on the method that the manufacturer can use.

[0028] (Difference in opening shape using the Dolan Bridge method) When viewed from the stacking direction D3, the second sacrificial layer 14 has a plurality of openings 14EX between the first electrode portion 121F and the second electrode portion 121S.

[0029] (Difference in opening shape using the Manhattan method) When viewed from the stacking direction D3, the second sacrificial layer 14 has at least one opening 14EX'. This opening 14EX' includes a first slit 14SL1 along the deposition direction D1 and a second slit 14SL2 along the deposition direction D2. The first slit 14SL1 and the second slit 14SL2 are connected to each other. When viewed from the stacking direction D3, the opening 14EX' has a + shape, an L shape, or a T shape. The opening 14EX' will be described later.

[0030] (Method for producing intermediates) An example of a method for manufacturing a quantum device intermediate will be described with reference to Fig. 5. The method for manufacturing a quantum device intermediate in this embodiment is carried out according to the flow shown in Fig. 5. The following description corresponds to a part of the method for producing a quantum device intermediate of the present disclosure.

[0031] First, the manufacturer stacks the superconductor layer 12 on the substrate 11 (step ST10: stacking step).

[0032] Following the execution of step ST10, the manufacturer stacks a first sacrificial layer 13 on the superconductor layer 12 (step ST11: step of stacking a first sacrificial layer). The first sacrificial layer 13 may or may not contain an organic material. In this case, the content of the organic material in the first sacrificial layer 13 is lower than the content of the organic material in the second sacrificial layer 14.

[0033] Following the execution of step ST11, the manufacturer laminates the second sacrificial layer 14 on the first sacrificial layer 13 (step ST12: a step of laminating the second sacrificial layer on the first sacrificial layer).

[0034] Following the execution of step ST12, the manufacturer may provide at least one opening 14EX (opening 14EX') in the second sacrificial layer 14. When providing the openings 14EX, the manufacturer provides a plurality of openings 14EX in the second sacrificial layer 14. When providing the openings 14EX', the manufacturer provides at least one opening 14EX' in the second sacrificial layer 14. At this time, the manufacturer may provide a cavity 13c in the first sacrificial layer 13.

[0035] (Quantum device configuration) Before describing an example of a quantum device manufacturing method, a quantum device 100 manufactured by processing a quantum device intermediate 10 will be described. 7, quantum device 100 includes a substrate 11, a superconductor layer 12, a first vapor-deposited layer 2, an oxide film 3, a second vapor-deposited layer 4, and at least one Josephson junction (JJ) 5. Quantum device 100 may further include a parasitic junction 6.

[0036] (Configuration of first vapor deposition layer) The first vapor-deposited layer 2 is a pattern for depositing the JJ 5 together with the second vapor-deposited layer 4 (hereinafter also referred to as the "first vapor-deposited pattern"). The first vapor-deposited layer 2 is partially laminated on the superconductor layer 12 . For example, the first vapor-deposited layer 2 may be a vapor-deposited layer deposited on the superconductor layer 12 by oblique vapor deposition from a direction oblique to the Z direction. For example, the first deposition layer 2 may be made of aluminum as a superconductor.

[0037] The oxide film is formed by oxidizing the surface of the first deposited layer 2. For example, AlOx having a predetermined thickness may be formed on the surface of the first deposited layer 2 by thermally oxidizing the surface of the first deposited layer 2, which is made of aluminum.

[0038] (Configuration of second vapor deposition layer) The second vapor-deposited layer 4 is partially laminated on the first vapor-deposited layer 2. The second vapor-deposited layer 4 may also be partially laminated on the superconductor layer 12. For example, the second deposited layer 4 may be a deposited layer deposited on the superconductor layer 12 by oblique deposition from an oblique direction different from that of the first deposited layer 2 with respect to the Z direction. For example, the second deposition layer 4 may be formed of aluminum as a superconductor.

[0039] The JJ5 is a structure consisting of a "superconductor-insulator thin film-superconductor" structure. In the quantum device of the present disclosure, the JJ5 is realized by "aluminum-AlOx-aluminum." In the quantum device 100 of the present disclosure, multiple JJ5s may be formed.

[0040] (Quantum device manufacturing method) An example of a method for manufacturing a quantum device will be described with reference to FIGS. The quantum device manufacturing method of this embodiment is carried out according to the flow shown in Fig. 6. Fig. 7 is a supplementary diagram of each step in Fig. 6. The following description corresponds to a portion of the quantum device manufacturing method of the present disclosure.

[0041] In the quantum device manufacturing method of the present disclosure, a quantum device intermediate 10 designated as Sample: A is used, as shown in Fig. 7. The quantum device intermediate 10 in question has the following characteristics.

[0042] The quantum device intermediate 10 comprises a substrate, a superconductor layer stacked on the substrate, a first sacrificial layer stacked on the superconductor layer, and a second sacrificial layer stacked on the first sacrificial layer, the second sacrificial layer containing an organic material, and the content of the organic material in the first sacrificial layer being lower than the content of the organic material in the second sacrificial layer.

[0043] First, the manufacturer uses the quantum device intermediate 10 to form at least one opening 14EX in the second sacrificial layer 14 using an electron beam (EB) (step ST20: step of forming an opening). For example, in step ST20, a plurality of openings 14EX may be formed in the second sacrificial layer 14. The opening 14EX is formed on the second sacrificial layer 14A by development with a developer after being patterned on the second sacrificial layer 14 using an EB exposure apparatus. When the quantum device intermediate already has the opening 14EX, as in quantum device intermediate 10A shown in FIG. 2, the manufacturer may omit step ST20.

[0044] Next, the manufacturer removes the second sacrificial layer 14 through the opening 14EX (step ST21: step of removing the first sacrificial layer). When step ST20 is omitted, the manufacturer starts the process from step ST21. When a quantum device intermediate already has cavity 13c, such as quantum device intermediate 10AA shown in FIG. 4, the manufacturer may omit step ST21. For example, the manufacturer removes a portion of the second sacrificial layer 14 with vapor phase hydrogen fluoride.

[0045] Next, the manufacturer laminates a pattern of the first vapor deposition layer 2 on the superconductor layer 12 and the substrate 11 (step ST22: a step of laminating a vapor deposition pattern). When step ST21 is omitted, the manufacturer starts the process from step ST21. For example, in step ST22, the manufacturer laminates the pattern of the first vapor deposition layer 2 on the superconductor layer 12 and the substrate 11 in a direction inclined toward the first direction (vapor deposition direction D1) with respect to the lamination direction D3.

[0046] Next, the worker oxidizes the surface of the first vapor-deposited layer 2 (step ST23: step of oxidizing the surface of the first vapor-deposited pattern). In this way, an oxide film 3, which is an insulating film, is formed on the surface of the first vapor-deposited layer 2.

[0047] Next, the manufacturer laminates the second deposited layer 4 at a position shifted in the X direction relative to the first deposited layer 2 so as to partially overlap the first deposited layer 2 (step ST24: step of laminating a second deposited pattern). For example, in step ST24, the manufacturer stacks a part of the second deposited layer 4 on the first deposited layer 2 via the oxide film 3 from a direction tilted in the second direction (deposition direction D1') with respect to the stacking direction D3. In this way, the JJ5 film is formed on the substrate surface 11s. At this time, a parasidec junction 6 can be formed on the surface of the superconductor layer 12. The parasidec junction 6 is a structure consisting of a "superconductor-superconductor-insulator thin film" structure. The parasidec junction 6 is unlikely to cause loss in the quantum bit.

[0048] Next, the manufacturer removes the mask layer including the first sacrificial layer 13 and the second sacrificial layer 14 (step ST25). The second sacrificial layer 14 and the Al vapor-deposited layer vapor-deposited on the second sacrificial layer 14 are lifted off with a stripping solution, and then the first sacrificial layer 13 is removed with gas-phase hydrogen fluoride. (end)

[0049] (Action and effect) According to the quantum device intermediate of the present disclosure, the quantum device intermediate 10 includes a superconductor layer 12 and a mask layer including a first sacrificial layer 13 and a second sacrificial layer 14 . Furthermore, when focusing on the mask layers, the content of the organic material in the first sacrificial layer 13 is lower than the content of the organic material in the second sacrificial layer 14 . Therefore, when quantum device 100 is manufactured from quantum device intermediate 10, first sacrificial layer 13 is removed after second sacrificial layer 14 is removed, so that organic materials are less likely to adhere to superconductor layer 12. Therefore, the quantum device intermediate according to the present disclosure can reduce adhesion of organic matter to the quantum bit circuit.

[0050] Another possible method is to remove organic matter adhering to the quantum bit circuit using a surface cleaning process such as argon milling, but this increases the number of processes. If organic matter adheres to the quantum bit circuit, the probability of undesirable quantum bit decoherence occurring may increase depending on the amount of organic matter adhering to the quantum bit circuit. Therefore, the quantum device intermediate of the present disclosure, which can reduce organic material residue as described above, can reduce the probability of decoherence occurring in quantum devices manufactured using this intermediate.

[0051] According to the quantum device manufacturing method of the present disclosure, the quantum device intermediate includes a superconductor layer and a mask layer including a first sacrificial layer and a second sacrificial layer. Furthermore, when focusing on the mask layers, the content of the organic material in the first sacrificial layer is smaller than the content of the organic material in the second sacrificial layer. Therefore, when a quantum device is manufactured from the quantum device intermediate, the first sacrificial layer is removed after the second sacrificial layer, and therefore, organic materials are less likely to adhere to the superconductor layer. Therefore, the quantum device manufacturing method according to the present disclosure can reduce adhesion of organic matter to the quantum bit circuit.

[0052] According to the method for manufacturing a quantum device intermediate of the present disclosure, the quantum device intermediate includes a superconductor layer and a mask layer including a first sacrificial layer and a second sacrificial layer. Furthermore, when focusing on the mask layers, the content of the organic material in the first sacrificial layer is smaller than the content of the organic material in the second sacrificial layer. Therefore, when a quantum device is manufactured from the quantum device intermediate, the first sacrificial layer is removed after the second sacrificial layer, and therefore, organic materials are less likely to adhere to the superconductor layer. Therefore, the method for producing a quantum device intermediate according to the present disclosure can reduce adhesion of organic matter to the quantum bit circuit.

[0053] A quantum device manufacturing method in a comparative example will be described. To create a quantum bit, a Josephson junction 5 is formed by a method such as the Doran Bridge method or the Manhattan method using two layers of resist. Dielectric loss is known to be one of the factors that reduce the loss of a quantum bit. Dielectric loss occurs when resist adheres to the surface of the wiring layer (superconductor layer 12) of the quantum device. It is thought that MMA, PMMA, PMGI, etc., which are listed as the second sacrificial layer 14, can cause dielectric loss. Therefore, the loss of quantum bits due to dielectric loss was a problem.

[0054] In contrast to the comparative example, in the quantum device intermediate, quantum device manufacturing method, and quantum device intermediate manufacturing method of the present disclosure, the lower resist layer located on the substrate surface 11s side of the two-layer resist is replaced with SiO2 or the like formed by sputtering. This can prevent organic matter originating from the resist from adhering to the surface of the wiring layer (superconductor layer 12) when forming the Josephson junction 5. As a result, an improvement in the energy relaxation time of the quantum bit can be expected.

[0055] Furthermore, the quantum device intermediate 10 of the present disclosure "has a substrate 11, a superconductor layer 12 stacked on the substrate 11, a first sacrificial layer 13 stacked on the superconductor layer 12, and a second sacrificial layer 14 stacked on the first sacrificial layer 13, and the content of organic material in the first sacrificial layer 13 is smaller than the content of organic material in the second sacrificial layer 14," thereby achieving the following effects. The quantum device intermediate 10 of the present disclosure includes a superconductor layer 12 and mask layers including a first sacrificial layer 13 and a second sacrificial layer 14 . Furthermore, when focusing on the mask layers, the content of the organic material in the first sacrificial layer 13 is lower than the content of the organic material in the second sacrificial layer 14 . Therefore, when quantum device 100 is manufactured from quantum device intermediate 10, first sacrificial layer 13 is removed after second sacrificial layer 14 is removed, so that organic materials are less likely to adhere to superconductor layer 12. Therefore, the quantum device intermediate 10 according to the present disclosure can reduce adhesion of organic matter to the quantum bit circuit.

[0056] Additionally, in the quantum device intermediate 10A of the present disclosure, "the superconductor layer 12 has a first electrode portion 121F and a second electrode portion 121S spaced apart from the first electrode portion 121F in the first direction, and when viewed from the stacking direction D3, the second sacrificial layer 14A has an opening 14EX between the first electrode portion 121F and the second electrode portion 121S," which also provides the effect that "cavity 13c is more easily formed by reactive ion etching via the opening 14EX."

[0057] In the first embodiment, the JJ5 is formed by the Dolan Bridge method. For example, the JJ5 is formed by the Dolan Bridge method, which requires two or more openings 14EX. In contrast, the JJ5 is formed by the Manhattan method shown in the second embodiment, which requires at least one opening 14EX'. In the quantum device intermediate 10A of the present disclosure, the second sacrificial layer 14 may have three or more openings 14EX between the first electrode portion 121F and the second electrode portion 121S. In this case, a plurality of JJ5s may be formed. In this case, a plurality of Josephson junctions connected in series is obtained. Similar advantages can be expected when there are a plurality of openings 14EX'.

[0058] Furthermore, in quantum device intermediate 10AA of the present disclosure, "first sacrificial layer 13 has cavity 13c communicating with opening 14EX", which provides the following effect. Through at least one opening 14EX in the second sacrificial layer 14 and the cavity 13c, the Josephson junction 5 can be deposited. As a result, it is possible to obtain the effect that "the JJ5 can be stably formed by oblique deposition via at least one opening 14EX and cavity 13c."

[0059] In the present disclosure, when it is stated that "when viewed from the stacking direction D3, the cavity 13c is an opening that encompasses the shape of at least one opening 14EX," the opening shape of the cavity 13c is an undercut shape. In this case, the first vapor deposition layer 2 (second vapor deposition layer 4) is less likely to adhere to the first sacrificial layer 13. Therefore, the first vapor deposition layer 2 (second vapor deposition layer 4) is easily removed.

[0060] Furthermore, in the quantum device intermediate 10, 10A, or 10AA of the present disclosure, the "first sacrificial layer 13 contains silicon oxide or silicon nitride," and by using gaseous hydrogen fluoride, the manufacturer can selectively remove the first sacrificial layer 13 without damaging the first vapor deposition layer 2 and the second vapor deposition layer 4.

[0061] Furthermore, in the quantum device intermediate 10, 10A, or 10AA of the present disclosure, the "second sacrificial layer contains a polymer," which makes it easier to perform drawing on the second sacrificial layer 14 using an EB exposure device. After drawing, the junction pattern of the JJ5 is controlled through at least one opening 14EX provided in the second sacrificial layer 14A by development with a developer. From the above, it is possible to obtain the effect that "the joining pattern of JJ5 is easily controlled."

[0062] Furthermore, in the quantum device intermediate 10, 10A, or 10AA of the present disclosure, the "superconductor layer contains titanium nitride, titanium niobium nitride, tantalum, or MoRe," so that the electrode surface is clean when the cavity 13c is formed in the first sacrificial layer 13A using vapor hydrogen fluoride (BHF). This eliminates the need for argon milling of the electrode surface, which is performed before aluminum deposition.

[0063] (Variation) Components common to those disclosed above are given the same reference numerals and detailed description thereof will be omitted. As shown in FIG. 8, a quantum device intermediate 70 designated as Sample B may be used. The first sacrificial layer 13′ may include an upper layer 132 and a lower layer 131. In this case, the resist sensitivity of the lower layer 131 is greater than the resist sensitivity of the upper layer 132. For example, the quantum device intermediate 70 includes a substrate 11, a superconductor layer 12, a first sacrificial layer 13′, and a second sacrificial layer 14. The upper layer 132 is a monomer, and the lower layer 131 is silicon oxide or silicon nitride.

[0064] When manufacturing the quantum device 100, processing is performed according to the flow of steps ST20 to ST25, similar to that disclosed above. Since the first sacrificial layer 13′ includes an upper layer portion 132 and a lower layer portion 131, a cavity 13c is formed in the upper layer portion 132 during EB exposure (step ST20). When a portion of the lower layer portion 131 is subsequently removed using gaseous hydrogen fluoride (step ST21), the lower layer portion 131 may have a cavity 13cc having a dimension larger than the dimension of the cavity 13c in the X direction. At this time, the first vapor deposition layer 2 (second vapor deposition layer 4) is less likely to adhere to the lower layer portion 131. Therefore, the first vapor deposition layer 2 (second vapor deposition layer 4) is easily removed by gaseous hydrogen fluoride. When lifted off using a remover, the Al vapor-deposited on the first sacrificial layer 13′ is easily removed.

[0065] Second Embodiment Hereinafter, an embodiment according to the present disclosure will be described with reference to the drawings. An example of the configuration of the quantum device intermediate 10 according to the present disclosure will be described below with reference to FIGS. In addition, components common to those disclosed above are given the same reference numerals and detailed description thereof will be omitted.

[0066] In the film formation of JJ5 by the Manhattan method shown in the second embodiment, at least one opening 14EX' is required. As described above, when viewed from the stacking direction D3, the second sacrificial layer 14 has at least one opening 14EX'. This opening 14EX' includes a first slit 14SL1 extending along the deposition direction D1 and a second slit 14SL2 extending along the deposition direction D. The first slit 14SL1 and the second slit 14SL2 are connected to each other. When viewed from the stacking direction D3, the opening 14EX' has a + shape, an L shape, or a T shape.

[0067] As shown in FIGS. 9 and 10, a quantum device intermediate 80 designated as Sample C includes a substrate 11, a superconductor layer 12′, a first sacrificial layer 13, and a second sacrificial layer . 10 , for example, the second sacrificial layer 14 may be a second sacrificial layer 14A' having at least one opening 14EX'. For example, the second sacrificial layer 14 in the following disclosure may be a second sacrificial layer 14A' having one opening 14EX'. The quantum device intermediate 80A includes a second sacrificial layer 14A' instead of the second sacrificial layer 14 included in the quantum device intermediate 80. For example, first sacrificial layer 13 may be first sacrificial layer 13A' having cavity 13c'. Cavity 13c' is an opening that has an enlarged shape of opening 14EX' when viewed from stacking direction D3. Quantum device intermediate 80A includes first sacrificial layer 13A' instead of first sacrificial layer 13 included in quantum device intermediate 80A.

[0068] The superconductor layer 12' differs in the positional relationship between the two electrodes (first electrode portion 121F, second electrode portion 121S) of the superconductor layer 12. In the superconductor layer 12', the first electrode portion 121F extends along a first direction D1, and the second electrode portion 121S extends along a second direction D2. When viewed from the stacking direction D3, the first slit 14SL1 extends to the second electrode portion 121S, and the second slit 14SL2 extends to the first electrode portion 121F.

[0069] Quantum device 100' is manufactured according to the same flow of steps ST20 to ST25 as disclosed above. JJ5' of quantum device 100' may have a different shape from JJ5 of quantum device 100.

[0070] For example, in step ST22, the manufacturer laminates the pattern of the first vapor deposition layer 2 on the superconductor layer 12 and the substrate 11 in a direction inclined toward the first direction (vapor deposition direction D1) with respect to the lamination direction D3.

[0071] For example, in step ST24, the manufacturer stacks a portion of the second deposition layer 4 on the first deposition layer 2 via the oxide film 3 from a direction tilted in the second direction (deposition direction D2) with respect to the stacking direction D3. The manufacturer may rotate the quantum device intermediate 80AA after step ST23 or step ST24 by 90 degrees within the substrate surface 11s. At this time, the manufacturer stacks the pattern of the second deposition layer 4 from a direction tilted in the first direction (deposition direction D1) with respect to the stacking direction D3.

[0072] (Action and effect) According to the quantum device intermediate of the present disclosure, quantum device intermediate 80 includes mask layers including first sacrificial layer 13 and second sacrificial layer 14 on superconductor layer 12 . Furthermore, when focusing on the mask layers, the content of the organic material in the first sacrificial layer 13 is lower than the content of the organic material in the second sacrificial layer 14 . Therefore, when quantum device 100 is manufactured from quantum device intermediate 10, first sacrificial layer 13 is removed after second sacrificial layer 14 is removed, so that organic materials are less likely to adhere to superconductor layer 12. Therefore, the quantum device intermediate according to the present disclosure can reduce adhesion of organic matter to the quantum bit circuit.

[0073] According to the quantum device manufacturing method of the present disclosure, the quantum device intermediate includes a superconductor layer and a mask layer including a first sacrificial layer and a second sacrificial layer. Furthermore, when focusing on the mask layers, the content of the organic material in the first sacrificial layer is smaller than the content of the organic material in the second sacrificial layer. Therefore, when a quantum device is manufactured from the quantum device intermediate, the first sacrificial layer is removed after the second sacrificial layer, and therefore, organic materials are less likely to adhere to the superconductor layer. Therefore, the quantum device manufacturing method according to the present disclosure can reduce adhesion of organic matter to the quantum bit circuit.

[0074] According to the method for manufacturing a quantum device intermediate of the present disclosure, the quantum device intermediate includes a superconductor layer and a mask layer including a first sacrificial layer and a second sacrificial layer. Furthermore, when focusing on the mask layers, the content of the organic material in the first sacrificial layer is smaller than the content of the organic material in the second sacrificial layer. Therefore, when a quantum device is manufactured from the quantum device intermediate, the first sacrificial layer is removed after the second sacrificial layer, and therefore, organic materials are less likely to adhere to the superconductor layer. Therefore, the method for producing a quantum device intermediate according to the present disclosure can reduce adhesion of organic matter to the quantum bit circuit.

[0075] Third Embodiment Hereinafter, an embodiment according to the present disclosure will be described with reference to the drawings. An example of the configuration of a quantum device intermediate according to the present disclosure will be described below with reference to FIG.

[0076] (composition) The quantum device intermediate 10m comprises a substrate 11m, a superconductor layer 12m stacked on the substrate 11m, a first sacrificial layer 13m stacked on the superconductor layer 12m, and a second sacrificial layer 14m stacked on the first sacrificial layer 13m, and the content of organic material in the first sacrificial layer 13m is smaller than the content of organic material in the second sacrificial layer 14m.

[0077] (Action and effect) According to the quantum device intermediate of the present disclosure, quantum device intermediate 10m includes a superconductor layer 12m and a mask layer including a first sacrificial layer 13m and a second sacrificial layer 14m. Furthermore, when focusing on the mask layer, the content of the organic material in the first sacrificial layer 13m is lower than the content of the organic material in the second sacrificial layer 14m. Therefore, when a quantum device is manufactured from the quantum device intermediate 10m, the first sacrificial layer 13m is removed after the second sacrificial layer 14m, and therefore, organic materials are less likely to adhere to the superconductor layer 12m. Therefore, the quantum device intermediate according to the present disclosure can reduce adhesion of organic matter to the quantum bit circuit.

[0078] <Fourth embodiment> Hereinafter, an embodiment according to the present disclosure will be described with reference to the drawings. An example of a method for producing a quantum device intermediate according to the present disclosure will be described below with reference to FIG. The method for manufacturing a quantum device intermediate according to the present disclosure is carried out according to the flow shown in FIG.

[0079] The method for manufacturing a quantum device intermediate includes the steps of stacking a superconductor layer on a substrate (step ST10m), stacking a first sacrificial layer on the superconductor layer (step ST11m), and stacking a second sacrificial layer on the first sacrificial layer (step ST12m), wherein the content of organic material in the first sacrificial layer is smaller than the content of organic material in the second sacrificial layer.

[0080] (Action and effect) According to the method for manufacturing a quantum device intermediate of the present disclosure, the quantum device intermediate includes a superconductor layer and a mask layer including a first sacrificial layer and a second sacrificial layer. Furthermore, when focusing on the mask layers, the content of the organic material in the first sacrificial layer is smaller than the content of the organic material in the second sacrificial layer. Therefore, when a quantum device is manufactured from the quantum device intermediate, the first sacrificial layer is removed after the second sacrificial layer, and therefore, organic materials are less likely to adhere to the superconductor layer. Therefore, the method for producing a quantum device intermediate according to the present disclosure can reduce adhesion of organic matter to the quantum bit circuit.

[0081] Fifth Embodiment Hereinafter, an embodiment according to the present disclosure will be described with reference to the drawings. An example of a quantum device manufacturing method according to the present disclosure will be described below with reference to FIG. The method for manufacturing a quantum device intermediate according to the present disclosure is carried out according to the flow shown in FIG.

[0082] A quantum device manufacturing method includes a quantum device intermediate including a substrate, a superconductor layer stacked on the substrate, a first sacrificial layer stacked on the superconductor layer, and a second sacrificial layer stacked on the first sacrificial layer, wherein the organic material content in the first sacrificial layer is lower than the organic material content in the second sacrificial layer, and includes the steps of: forming an opening in the second sacrificial layer with a beam (step ST20m); removing the first sacrificial layer through the opening (step ST21m); stacking a first vapor deposition pattern on the superconductor layer and the substrate (step ST22m); oxidizing the surface of the first vapor deposition pattern (step ST23m); and stacking a second vapor deposition pattern at a position laterally shifted from the first vapor deposition pattern so that it partially overlaps the first vapor deposition pattern (step ST24m).

[0083] (Action and effect) According to the quantum device manufacturing method of the present disclosure, the quantum device intermediate includes a superconductor layer and a mask layer including a first sacrificial layer and a second sacrificial layer. Furthermore, when focusing on the mask layers, the content of the organic material in the first sacrificial layer is smaller than the content of the organic material in the second sacrificial layer. Therefore, when a quantum device is manufactured from the quantum device intermediate, the first sacrificial layer is removed after the second sacrificial layer, and therefore, organic materials are less likely to adhere to the superconductor layer. Therefore, the method for producing a quantum device intermediate according to the present disclosure can reduce adhesion of organic matter to the quantum bit circuit.

[0084] Although the present disclosure has been described above with reference to the embodiments, the present disclosure is not limited to the above-described embodiments. The configuration and details of the present disclosure, including the shape, materials, etc., can be subject to various modifications that are understandable to those skilled in the art within the scope of the present disclosure. Furthermore, each embodiment can be combined with other embodiments as appropriate.

[0085] <Other variations> In the above example, an electron beam is used to form the opening in the second sacrificial layer, but an ion beam or a light beam may also be used.

[0086] A part or all of the above-described embodiments can be described as, but not limited to, the following supplementary notes.

[0087] (Appendix 1) A substrate; a superconductor layer laminated on the substrate; a first sacrificial layer laminated on the superconductor layer; a second sacrificial layer laminated on the first sacrificial layer; Equipped with the content of the organic material in the first sacrificial layer is smaller than the content of the organic material in the second sacrificial layer; Quantum device intermediate.

[0088] (Appendix 2) the superconductor layer has a first electrode portion and a second electrode portion spaced apart from the first electrode portion in a first direction, When viewed from the stacking direction, the second sacrificial layer has an opening between the first electrode portion and the second electrode portion. 2. A quantum device intermediate according to claim 1.

[0089] (Appendix 3) the opening includes a first slit extending along a first direction and a second slit extending along a second direction intersecting the first direction; The first slit and the second slit are coupled together. 3. A quantum device intermediate according to claim 2.

[0090] (Appendix 4) the first sacrificial layer has a cavity communicating with the opening; A quantum device intermediate according to Appendix 2 or Appendix 3.

[0091] (Appendix 5) the first sacrificial layer comprises silicon oxide or silicon nitride; 5. A quantum device intermediate according to any one of claims 1 to 4.

[0092] (Appendix 6) the second sacrificial layer comprises a polymer; 6. A quantum device intermediate according to any one of claims 1 to 5.

[0093] (Appendix 7) the second sacrificial layer includes an upper layer portion and a lower layer portion; the resist sensitivity of the lower layer portion is greater than the resist sensitivity of the upper layer portion; 7. A quantum device intermediate according to claim 6.

[0094] (Appendix 8) the superconductor layer comprises titanium nitride, titanium niobium nitride, tantalum, or MoRe; 8. A quantum device intermediate according to any one of claims 1 to 7.

[0095] (Appendix 9) a quantum device intermediate including a substrate, a superconductor layer stacked on the substrate, a first sacrificial layer stacked on the superconductor layer, and a second sacrificial layer stacked on the first sacrificial layer, wherein the content of organic material in the first sacrificial layer is lower than the content of organic material in the second sacrificial layer, creating an opening in the second sacrificial layer with a beam; removing the first sacrificial layer through the opening; depositing a first deposition pattern on the superconductor layer and the substrate; oxidizing the surface of the first deposition pattern; and laminating a second vapor-deposited pattern at a position laterally offset from the first vapor-deposited pattern so as to partially overlap the first vapor-deposited pattern. Quantum device manufacturing methods.

[0096] (Appendix 10) the superconductor layer has a first electrode portion and a second electrode portion spaced apart from the first electrode portion in a first direction, In the step of providing an opening, an opening is provided between the first electrode portion and the second electrode portion; In the step of stacking the first vapor deposition pattern, the first vapor deposition pattern is stacked on the superconductor layer and the substrate in a direction tilted with respect to a stacking direction of the quantum device intermediate body. 10. A quantum device manufacturing method as recited in claim 9.

[0097] (Appendix 11) the opening includes a first slit extending along a first direction and a second slit extending along a second direction intersecting the first direction; The first slit and the second slit are coupled together, In the step of stacking the first vapor deposition pattern, the first vapor deposition pattern is stacked on the superconductor layer and the substrate in a direction inclined to the first direction with respect to a stacking direction of the quantum device intermediate body; In the step of stacking the second vapor deposition pattern, a portion of the second vapor deposition pattern is stacked on the first vapor deposition pattern in a direction tilted toward the second direction with respect to a stacking direction of the quantum device intermediate body. 11. A quantum device manufacturing method as recited in claim 10.

[0098] (Appendix 12) In the step of removing the first sacrificial layer, the first sacrificial layer is removed with gaseous hydrogen fluoride. 12. A quantum device manufacturing method according to any one of claims 9 to 11.

[0099] (Appendix 13) the superconductor layer comprises titanium nitride, titanium niobium nitride, tantalum, or MoRe; 13. A quantum device manufacturing method as recited in claim 12.

[0100] (Appendix 14) depositing a superconductor layer on a substrate; depositing a first sacrificial layer on the superconductor layer; depositing a second sacrificial layer on the first sacrificial layer; Including, the content of the organic material in the first sacrificial layer is smaller than the content of the organic material in the second sacrificial layer; A method for producing a quantum device intermediate. [Explanation of symbols]

[0101] 10 Quantum Device Intermediates 10A Quantum Device Intermediate 10AA Quantum Device Intermediate 11 Circuit Board 11s board surface 12 Superconductor layer 121F First electrode part 121S Second electrode part 13 First Sacrificial Layer 13A First Sacrificial Layer 13c cavity 14 Second Sacrificial Layer 14A Second Sacrificial Layer 14EX aperture 10m quantum device intermediate 11m board 12m superconductor layer 13m First Sacrificial Layer 14m Second Sacrificial Layer 70 Quantum Device Intermediates 13' First Sacrificial Layer 131 Lower part 13cc cavity 132 Upper Management 13c' cavity 80 Quantum Device Intermediates 80A Quantum Device Intermediate 13A' First Sacrificial Layer 80AA Quantum Device Intermediate 14A' Second Sacrificial Layer 14EX' opening 100 Quantum Devices 2 First vapor deposited layer 3. Oxide film 4 Second vapor deposited layer 5. Josephson junction (JJ) 6 Parasitic Junction 100' quantum device D1 Deposition direction D1' Deposition direction D2 Deposition direction D3 Stacking direction

Claims

1. A substrate; a superconductor layer laminated on the substrate; a first sacrificial layer laminated on the superconductor layer; a second sacrificial layer laminated on the first sacrificial layer; Equipped with the content of the organic material in the first sacrificial layer is smaller than the content of the organic material in the second sacrificial layer; Quantum device intermediate.

2. the superconductor layer has a first electrode portion and a second electrode portion spaced apart from the first electrode portion in a first direction, When viewed from the stacking direction, the second sacrificial layer has an opening between the first electrode portion and the second electrode portion. The quantum device intermediate according to claim 1 .

3. the opening includes a first slit extending along a first direction and a second slit extending along a second direction intersecting the first direction; The first slit and the second slit are coupled together. The quantum device intermediate according to claim 2 .

4. the first sacrificial layer has a cavity communicating with the opening; The quantum device intermediate according to claim 2 or 3.

5. the second sacrificial layer comprises a polymer; The quantum device intermediate according to any one of claims 1 to 3.

6. a quantum device intermediate including a substrate, a superconductor layer stacked on the substrate, a first sacrificial layer stacked on the superconductor layer, and a second sacrificial layer stacked on the first sacrificial layer, wherein the content of organic material in the first sacrificial layer is lower than the content of organic material in the second sacrificial layer, creating an opening in the second sacrificial layer with a beam; removing the first sacrificial layer through the opening; depositing a first deposition pattern on the superconductor layer and the substrate; oxidizing the surface of the first deposition pattern; depositing a second vapor deposition pattern at a position laterally offset from the first vapor deposition pattern so as to partially overlap the first vapor deposition pattern; Including, Quantum device manufacturing methods.

7. the superconductor layer has a first electrode portion and a second electrode portion spaced apart from the first electrode portion in a first direction, In the step of providing an opening, an opening is provided between the first electrode portion and the second electrode portion; In the step of stacking the first vapor deposition pattern, the first vapor deposition pattern is stacked on the superconductor layer and the substrate in a direction inclined with respect to a stacking direction of the quantum device intermediate body. The quantum device manufacturing method according to claim 6 .

8. the opening includes a first slit extending along a first direction and a second slit extending along a second direction intersecting the first direction; The first slit and the second slit are coupled together, In the step of stacking the first vapor deposition pattern, the first vapor deposition pattern is stacked on the superconductor layer and the substrate in a direction inclined to the first direction with respect to a stacking direction of the quantum device intermediate body; In the step of stacking the second vapor deposition pattern, a portion of the second vapor deposition pattern is stacked on the first vapor deposition pattern in a direction tilted toward the second direction with respect to a stacking direction of the quantum device intermediate body. The quantum device manufacturing method according to claim 7 .

9. In the step of removing the first sacrificial layer, the first sacrificial layer is removed with gaseous hydrogen fluoride. The quantum device manufacturing method according to any one of claims 6 to 8.

10. depositing a superconductor layer on a substrate; depositing a first sacrificial layer on the superconductor layer; depositing a second sacrificial layer on the first sacrificial layer; Including, the content of the organic material in the first sacrificial layer is smaller than the content of the organic material in the second sacrificial layer; A method for producing a quantum device intermediate.

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