Preparation method of multiple superconducting material layers and quantum device

Abstract

The present invention discloses a method for preparing multiple superconducting material layers and a quantum device. The method comprises: depositing a first superconducting material layer on a substrate, with the first superconducting material within the first target region covered by a first hard mask; depositing a second superconducting material on the substrate deposited with the first superconducting material layer; covering the second superconducting material with a second hard mask; and etching the second hard mask and the second superconducting material to obtain a second superconducting material layer, with the second superconducting material within the second target region covered by the second hard mask. This invention solves the technical problem of the difficulty of integrating multiple superconducting materials on the same substrate.

Description

Technical Field

[0001] The present invention relates to the field of superconducting quantum devices, and in particular to a method for preparing multiple superconducting material layers and a quantum device. Background Art

[0002] In related technologies, simple organic photoresists are usually used to achieve regional growth, but photoresists will introduce secondary pollution and have a very low thermal budget, which is not universally applicable. Alternatively, a stripping method is used for regional selective growth, but this method has high requirements for the preparation equipment, and due to the use of photoresists, the thermal budget is very low, which is also not universally applicable.

[0003] Therefore, in the related art, there is a technical problem that it is difficult to integrate multiple superconducting materials on the same substrate.

[0004] To address the above-mentioned problems, no effective solutions have been proposed so far. Summary of the Invention

[0005] The embodiments of the present invention provide a method for preparing multiple superconducting material layers and a quantum device, so as to at least solve the technical problem of difficulty in integrating multiple superconducting materials on the same substrate.

[0006] According to one aspect of an embodiment of the present invention, a method for preparing multiple superconducting material layers is provided, comprising: depositing a first superconducting material layer of a first superconducting material within a first target area on a substrate, the layer being covered by a first hard mask within a first target area; depositing a second superconducting material on the substrate on which the first superconducting material layer is deposited; covering the second superconducting material with a second hard mask; and etching the second hard mask and the second superconducting material to obtain a second superconducting material layer of a second superconducting material within a second target area, the layer being covered by a second hard mask within a second target area.

[0007] Optionally, the step of depositing a first superconducting material layer of a first superconducting material in a first target area range covered by a first hard mask in a first target area range on a substrate includes: depositing the first superconducting material on the substrate; covering the first superconducting material with the first hard mask; determining the first target area range on the substrate where the first superconducting material is to remain; and gradually etching away the first hard mask in a first other area range in the first hard mask and the superconducting material in the first other area in the first superconducting material to obtain the first superconducting material layer of the first superconducting material in the first target area range covered by the first hard mask in the first target area range, wherein the first other area range is an area range on the substrate other than the first target area range.

[0008] Optionally, the etching of the second hard mask and the second superconducting material to obtain a second superconducting material layer in which the second superconducting material in the second target area is covered by the second hard mask in the second target area includes: gradually etching away the second hard mask in the second other area in the second hard mask, and the superconducting material in the second other area in the second superconducting material, to obtain a second superconducting material layer, wherein the second other area is an area on the substrate excluding the second target area, and the second superconducting material layer is the second superconducting material in which the second target area is covered by the second hard mask in the second target area.

[0009] Optionally, after etching the second hard mask and the second superconducting material to obtain a second superconducting material layer in which the second hard mask in the second target area covers the second superconducting material in the second target area, the method further includes: etching away the first hard mask on the first superconducting material layer and the second hard mask on the second superconducting material layer to obtain a first target superconducting device on the substrate.

[0010] Optionally, etching away the first hard mask on the first superconducting material layer and the second hard mask on the second superconducting material layer to obtain the first target superconducting device on the substrate includes: using a hydrofluoric acid (DHF) solution to etch away the first hard mask on the first superconducting material layer and the second hard mask on the second superconducting material layer to obtain the first target superconducting device on the substrate.

[0011] Optionally, after etching the second hard mask and the second superconducting material to obtain a second superconducting material layer of the second superconducting material in the second target area range covered by the second hard mask in the second target area range, the method further includes: depositing a third superconducting material on the first superconducting material layer and on a first other area range, wherein the first other area range is an area range on the substrate other than the first target area range; covering the third superconducting material with nitride as a third hard mask; determining a third target area range on the substrate where the third superconducting material is to remain; and etching the third hard mask and the third superconducting material to obtain a third superconducting material layer of the third superconducting material in the third target area range covered by the third hard mask in the third target area range.

[0012] Optionally, the etching of the third hard mask and the third superconducting material to obtain a third superconducting material layer in which the third superconducting material in the third target area is covered by the third hard mask in the third target area includes: gradually etching away the third hard mask in the third other area in the third hard mask, and the superconducting material in the third other area in the third superconducting material, to obtain a third superconducting material layer in which the third superconducting material in the third target area is covered by the third hard mask in the third target area, wherein the third other area is an area on the substrate other than the third target area.

[0013] Optionally, after etching the third hard mask and the third superconducting material to obtain a third superconducting material layer in which the third superconducting material in the third target area is covered by the third hard mask in the third target area, the method further includes: etching away the first hard mask on the first superconducting material layer, the second hard mask on the second superconducting material layer, and the third hard mask on the third superconducting material layer to obtain a second target superconducting device on the substrate.

[0014] Optionally, the first hard mask is silicon nitride, and the second hard mask is silicon nitride.

[0015] Optionally, a combination of photolithography and dry etching is used to etch away the first hard mask in the first other area of ​​the first hard mask, the second hard mask in the second other area of ​​the second hard mask is etched away, and the third hard mask in the third other area of ​​the third hard mask is etched away; and wet etching is used to etch away the superconducting material in the first other area of ​​the first superconducting material, the superconducting material in the second other area of ​​the second superconducting material, and the superconducting material in the third other area of ​​the third superconducting material.

[0016] Optionally, the etchant used in the wet etching method is SC-1 solution.

[0017] According to another aspect of the present invention, a method for preparing a multi-superconducting material layer is provided, comprising: depositing a first titanium nitride layer on a substrate in which a first silicon nitride in a first target area covers a first titanium nitride in a first target area, wherein the thickness of the first titanium nitride in the first titanium nitride layer is a first thickness; depositing a second titanium nitride on the substrate on which the first titanium nitride layer is deposited; covering the second titanium nitride with the second silicon nitride; and etching the second silicon nitride and the second titanium nitride to obtain a first titanium nitride layer in which a second silicon nitride in a second target area covers a second titanium nitride in a second target area, wherein the thickness of the second titanium nitride in the second titanium nitride layer is a second thickness, and the first thickness is different from the second thickness.

[0018] According to another aspect of the present invention, a quantum device is provided, comprising circuit elements formed of multiple superconducting materials, wherein the multiple superconducting materials are obtained by any of the above methods for preparing multiple superconducting material layers.

[0019] Optionally, the quantum device is a Fluxonium quantum bit.

[0020] According to another aspect of the present invention, a superconducting circuit is provided, comprising the above-mentioned quantum device.

[0021] According to another aspect of the present invention, a quantum chip is provided, comprising the above-mentioned quantum device.

[0022] According to another aspect of the present invention, there is provided a quantum computer comprising: a quantum memory and the above-mentioned quantum chip.

[0023] In an embodiment of the present invention, through the above steps, superconducting materials are deposited on the substrate in sequence according to the types of materials to be integrated, and after each superconducting material is deposited, a hard mask is covered thereon. After determining the target area range of the superconducting material to be deposited each time on the substrate, etching is used to cleverly achieve the technical effect of regional integration of multiple superconducting materials on the same substrate, thereby solving the technical problem of difficulty in integrating multiple superconducting materials on the same substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0025] Figure 1 is a flow chart of a method for preparing multiple superconducting material layers according to an embodiment of the present invention;

[0026] Figure 2 This is a flow chart of integrating titanium nitride of different thicknesses on a substrate according to an embodiment of the present invention;

[0027] Figure 3 is an integrated schematic diagram provided according to an optional embodiment of the present invention;

[0028] Figure 4 is a schematic diagram of wet etching provided according to an optional embodiment of the present invention;

[0029] Figure 5 is a schematic diagram of photolithography provided according to an optional embodiment of the present invention;

[0030] Figure 6is a material deposition and patterning flow chart provided according to an optional embodiment of the present invention;

[0031] Figure 7a is a schematic diagram of an optical image provided according to an optional embodiment of the present invention;

[0032] Figure 7b is an atomic force microscope scan provided according to an optional embodiment of the present invention;

[0033] Figure 7c is a schematic diagram of the surface of a TiN film provided according to an optional embodiment of the present invention;

[0034] Figure 7d This is an example of an X-ray scan result provided by an optional embodiment of the present invention. Figure 1 ;

[0035] Figure 7e This is an example of an X-ray scan result provided by an optional embodiment of the present invention. Figure 2 ;

[0036] Figure 8 Schematic diagram of a quantum computer provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0037] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described 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 should fall within the scope of protection of the present invention.

[0038] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0039] First, some nouns or terms that appear in the description of the embodiments of the present application are subject to the following interpretations:

[0040] Thermal budget refers to the amount of heat that silicon is exposed to during processing. One of the goals of semiconductor processing is to minimize the amount of heat required to heat the silicon. A key factor in determining most silicon-based semiconductor processing conditions is minimizing the thermal budget by reducing the temperature or time required to process the silicon.

[0041] Etching is a crucial step in semiconductor manufacturing, microelectronic integrated circuit (IC) manufacturing, and micro-nano manufacturing. It is a key patterning process associated with photolithography. Etching, in a narrower sense, is photolithographic etching. The photoresist is first exposed through photolithography, and then the desired portions are etched away using other methods. Etching selectively removes unwanted material from the surface of a silicon wafer using chemical or physical methods. Its primary goal is to accurately replicate the mask pattern on the coated silicon wafer. With the advancement of microfabrication, etching has broadly come to encompass the removal of material using solutions, reactive ions, or other mechanical methods, becoming a universal term for microfabrication. The simplest and most commonly used classifications of etching are dry etching and wet etching. The obvious difference between the two is that wet etching uses solvents or solutions. Wet etching is a purely chemical reaction process, which refers to the use of chemical reactions between the solution and the pre-etched material to remove the parts not masked by the masking film material to achieve the etching purpose. The advantages of wet etching are good selectivity, good repeatability, high production efficiency, simple equipment and low cost. There are many types of dry etching, including photoevaporation, vapor phase etching, plasma etching, etc. According to the type of material to be etched, dry etching is mainly divided into three types: metal etching, dielectric etching and silicon etching. Dielectric etching is used for etching dielectric materials, such as silicon dioxide. The advantages of dry etching are: good anisotropy, high selectivity, controllability, flexibility, good repeatability, safe fine line operation, easy automation, no chemical waste liquid, no pollution introduced during the treatment process, and high cleanliness.

[0042] Epitaxial growth refers to the growth of a single crystal layer with the same crystal orientation as the substrate, on a single crystal substrate (substrate), as if the original crystal has been extended outward. The development of epitaxial growth technology is driven by the need to manufacture high-frequency, high-power devices, which require reducing the collector series resistance while also requiring the material to withstand high voltage and high current. Therefore, a thin, high-resistance epitaxial layer must be grown on a low-resistance substrate. The new epitaxially grown single crystal layer can differ from the substrate in conductivity type and resistivity, and multiple layers of single crystals with varying thicknesses and requirements can be grown, greatly enhancing device design flexibility and performance. Epitaxial processes are also widely used in PN junction isolation technology in integrated circuits and to improve material quality in large-scale integrated circuits.

[0043] Wafers are silicon wafers used to make silicon semiconductor circuits. The starting material is silicon. High-purity polycrystalline silicon is dissolved, doped with silicon seed crystals, and then slowly pulled out to form cylindrical single crystals. Silicon ingots are then ground, polished, and sliced ​​to form silicon wafers, also known as wafers.

[0044] Silicon wafer cleaning agents (SC) are widely used for cleaning silicon wafers in the photovoltaic and electronics industries. Because silicon wafers can become contaminated during transportation, surface cleanliness is often compromised, significantly impacting the subsequent corrosion and etching processes. Therefore, a series of cleaning operations must be performed on the wafer surface. The general cleaning process begins by removing organic contaminants from the surface, followed by dissolving the oxide film, which acts as a "contamination trap" and can cause epitaxial defects. Particles and metals are then removed, while simultaneously passivating the wafer surface. SC-1 cleaning solution is an alkaline solution that removes particles and organic matter, while the SC-2 wet cleaning process is used to remove metals from the wafer surface.

[0045] Example 1

[0046] According to an embodiment of the present invention, an embodiment of a method for preparing multiple superconducting material layers is provided. Figure 1 FIG. 1 is a flow chart of a method for preparing multiple superconducting material layers according to an embodiment of the present invention. Figure 1 As shown, the method includes the following steps:

[0047] Step S102 , depositing a first superconducting material layer of a first superconducting material in a first target area covered by a first hard mask in a first target area on the substrate;

[0048] Step S104, depositing a second superconducting material on the substrate on which the first superconducting material layer is deposited;

[0049] Step S106, covering the second superconducting material with a second hard mask;

[0050] Step S108 , etching the second hard mask and the second superconducting material to obtain a second superconducting material layer in which the second superconducting material in the second target area is covered by the second hard mask in the second target area.

[0051] Through the above steps, the superconducting materials are deposited on the substrate in sequence according to the types of materials to be integrated. After each superconducting material is deposited, a hard mask is covered on it. After determining the target area range of the superconducting material to be deposited each time on the substrate, etching is used to cleverly achieve the technical effect of regional integration of multiple superconducting materials on the same substrate, thereby solving the technical problem of difficulty in integrating multiple superconducting materials on the same substrate.

[0052] As an optional embodiment, depositing a first superconducting material layer of a first superconducting material in a first target area range covered by a first hard mask in a first target area range on a substrate includes: depositing the first superconducting material on the substrate; covering the first superconducting material with a first hard mask; determining a first target area range on the substrate where the first superconducting material is to remain; and gradually etching away the first hard mask in a first other area range in the first hard mask and the superconducting material in the first other area in the first superconducting material to obtain a first superconducting material layer of the first superconducting material in a first target area range covered by the first hard mask in the first target area range, wherein the first other area range is an area range on the substrate other than the first target area range.

[0053] After the first hard mask is applied to the first superconducting material deposited on the substrate, etching away the first hard mask in first other regions of the substrate excluding the first target region within the first hard mask can be performed in a variety of ways. For example, a combination of photolithography and dry etching can be used to etch away the first hard mask in the first other regions. When etching away the superconducting material in the first other regions of the substrate excluding the first target region within the first superconducting material, so that the resulting first superconducting material layer is a combination of the first hard mask in the first target region covering the first superconducting material in the first target region on the substrate, a variety of ways can also be used. For example, wet etching can be used to etch away the superconducting material in the first other regions of the first superconducting material.

[0054] The process of depositing the second superconducting material layer is similar to that of depositing the first superconducting material layer. Both methods involve first depositing a layer of superconducting material on a substrate, then depositing a hard mask on the superconducting material, and then etching away the hard mask and superconducting material in areas other than the target area using a combination of photolithography, dry etching, and wet etching to obtain a superconducting material layer in which the hard mask covers the target area. The difference between the second superconducting material layer and the first superconducting material layer is that the superconducting material and the superconducting material used in the two depositions are different, thereby achieving the goal of integrating different superconducting materials on the same substrate. When removing the hard mask using photolithography and dry etching, the hard mask is first patterned using photolithography to determine the patterned area of ​​the hard mask to be removed. Dry etching is then used to etch away the hard mask based on the determined patterned area.

[0055] As an optional embodiment, the second hard mask and the second superconducting material are etched to obtain a second superconducting material layer in which the second superconducting material in the second target area is covered by the second hard mask in the second target area, including: gradually etching away the second hard mask in the second other area in the second hard mask, and etching away the superconducting material in the second other area in the second superconducting material to obtain the second superconducting material layer, wherein the second other area is the area on the substrate other than the second target area, and the second superconducting material layer is the second superconducting material in the second target area covered by the second hard mask in the second target area.

[0056] When etching away the second hard mask in the second other region of the second hard mask, various methods may be employed, such as a combination of photolithography and dry etching. When etching away the superconducting material in the second other region of the second superconducting material, various methods may be employed, such as wet etching.

[0057] It should be noted that the above-described deposition of the first superconducting material layer and the second superconducting material layer on the substrate is merely an example. Depending on specific deposition requirements or if the substrate is subsequently used to fabricate different superconducting devices, more types of superconducting material layers may be deposited on the substrate, and these examples are not given here.

[0058] As an optional embodiment, after etching the second hard mask and the second superconducting material to obtain a second superconducting material layer in which the second superconducting material in the second target region is covered by the second hard mask in the second target region, the process further includes etching away the first hard mask on the first superconducting material layer and the second hard mask on the second superconducting material layer to obtain a first target superconducting device on the substrate. After the first superconducting material and the second superconducting material are simultaneously integrated on the same substrate, the desired superconducting device is fabricated based on the process and preparation steps for fabricating the superconducting device. Subsequently, superconducting circuits, superconducting chips, quantum chips, and quantum computers can be fabricated based on the fabricated superconducting device.

[0059] As an optional embodiment, when etching away the first hard mask on the first superconducting material layer and the second hard mask on the second superconducting material layer to obtain the first target superconducting device on the substrate, a hydrofluoric acid DHF solution can be used to etch away the first hard mask on the first superconducting material layer and the second hard mask on the second superconducting material layer to obtain the first target superconducting device on the substrate.

[0060] After two different superconducting materials have been integrated on the substrate, that is, the first superconducting material layer and the second superconducting material layer have been deposited on the substrate, according to actual application requirements, if only the first superconducting material and the second superconducting material are to be integrated on the substrate, then after the first superconducting material layer and the second superconducting material layer are deposited, the hard masks covering the superconducting materials can be uniformly processed. For example, a wet etching method can be used to etch away the first hard mask on the first superconducting material layer and the second hard mask on the second superconducting material layer using a hydrofluoric acid (DHF) solution. The hydrofluoric acid (DHF) solution will only dissolve the hard mask, but will not dissolve the superconducting material, or will dissolve the superconducting material at a very slow rate, so that only the hard mask is removed. Because the wet etching method is used, that is, the hard mask on the first superconducting material layer and the second superconducting material layer is etched away by using a solution etchant, compared with the photoresist etching method, the solution etchant can penetrate into the edges where the hard mask contacts the superconducting material. Therefore, the hard mask at the edge gap of the superconducting material can be removed more thoroughly, making the first superconducting material and the second superconducting material integrated on the substrate purer, providing a basis for the subsequent preparation of precise superconducting devices.

[0061] As an optional embodiment, after etching the second hard mask and the second superconducting material to obtain a second superconducting material layer in which the second superconducting material in the second target region is covered by the second hard mask, other superconducting material layers may be further integrated on the substrate for subsequent device fabrication needs. For example, a third superconducting material may be deposited on the first superconducting material layer and on a first other region, where the first other region is an area on the substrate other than the first target region; nitride may be used as a third hard mask to cover the third superconducting material; a third target region on the substrate where the third superconducting material is to remain may be determined; and the third hard mask and the third superconducting material may be etched to obtain a third superconducting material layer in which the third superconducting material in the third target region is covered by the third hard mask. A similar processing method to the above-described integration of the second superconducting material layer is used to obtain the second superconducting material layer on the substrate, i.e., integrate the second superconducting material on the substrate.

[0062] As an optional embodiment, etching the third hard mask and the third superconducting material to obtain a third superconducting material layer in which the third hard mask in the third target region covers the third superconducting material in the third target region includes: gradually etching away the third hard mask in third other regions within the third hard mask, and etching away the superconducting material in third other regions within the third superconducting material, to obtain the third superconducting material layer in which the third hard mask in the third target region covers the third superconducting material in the third target region, wherein the third other regions are regions on the substrate excluding the third target region. Based on a similar process to that described above for obtaining the second superconducting material layer, a combination of photolithography and dry etching is employed to etch away the third hard mask in the third other regions within the third hard mask. Due to the advantages of mature technology and high efficiency of the combined photolithography and dry etching process, the third superconducting material layer can be efficiently obtained. In addition, the superconducting material in the third other region of the third superconducting material is etched away by wet etching, and the etchant selected by the wet etching method can be better dissolved in the superconducting material and is incompatible with the hard mask, so that the etching of the superconducting material in the third other region is more thorough, effectively ensuring the precision of the third superconducting material layer.

[0063] As an optional embodiment, after etching the third hard mask and the third superconducting material to obtain a third superconducting material layer in which the third hard mask in the third target area covers the third superconducting material in the third target area, it also includes: etching away the first hard mask on the first superconducting material layer, the second hard mask on the second superconducting material layer, and the third hard mask on the third superconducting material layer to obtain a second target superconducting device on the substrate.

[0064] After two different superconducting materials have been integrated on the substrate, that is, the first superconducting material layer and the second superconducting material layer have been deposited on the substrate, if a third superconducting material still needs to be integrated on the substrate according to actual application needs, the third superconducting material layer can be deposited again using a method similar to the deposition of the first and second superconducting material layers after the first and second superconducting material layers are deposited. After the deposition is completed, the hard mask is removed together with the first and second superconducting material layers.

[0065] Therefore, the above-mentioned method for etching away the mask can be a combination of photolithography and dry etching, and the method for etching away the superconducting material can be wet etching. For example, a combination of photolithography and dry etching can be used to etch away the first hard mask in the first other region of the first hard mask, the second hard mask in the second other region of the second hard mask, and the third hard mask in the third other region of the third hard mask; wet etching can be used to etch away the superconducting material in the first other region of the first superconducting material, the superconducting material in the second other region of the second superconducting material, and the superconducting material in the third other region of the third superconducting material.

[0066] It should be noted that the method of the embodiment of the present application is not limited to the integration of two or three superconducting materials, but can realize regional integration of multiple superconducting materials on the substrate according to the above-mentioned integration method according to actual application needs.

[0067] It should be noted that when different superconducting materials need to be integrated on the same horizontal plane of the substrate, the method in the above embodiment can be used. If different superconducting materials need to be integrated on a vertical plane, after the superconducting material at the bottom is integrated, the hard mask covering the superconducting material can be etched first to expose the superconducting material to be at the bottom, and then a layer of superconducting material to be at the top can be deposited on the exposed superconducting material.

[0068] As an optional embodiment, the hard masks used in the process of obtaining the three superconducting material layers, namely the first hard mask, the second hard mask, and the third hard mask, can be masks of the same material, or masks of different materials with similar properties. For example, the first hard mask, the second hard mask, and the third hard mask can all be nitrides. The nitride can be silicon nitride, for example.

[0069] It should be noted that the material of the above-mentioned third hard mask can be the same as that of the first hard mask and the second hard mask, that is, nitride (for example, silicon nitride). By making the material of the third hard mask the same as that of the first hard mask and the second hard mask, it is also convenient to use an etching solution (for example, hydrofluoric acid DHF solution) to uniformly remove the hard masks after the integration of various superconducting materials is completed.

[0070] As an optional embodiment, the wet etching method employed in etching the superconducting material may be a method employing a predetermined etchant. A variety of predetermined etchants may be selected, as long as they can thoroughly etch the corresponding superconducting material without affecting the mask requiring protection. For example, the predetermined etchant may be an SC-1 solution.

[0071] In the embodiments of the present invention, the key point in selecting the solution used for wet etching is to find a solution that can only etch the superconducting material without affecting the hard mask, and a solution that can only etch the hard mask without affecting the superconducting material. This can be determined by, on the one hand, whether the solution can dissolve the corresponding material independently, and on the other hand, by the degree of difference in the dissolution rate of the solution for different materials. For example, an SC-1 solution is used to dissolve the superconducting material (the superconducting material can be a nitrogen-based superconducting material, such as titanium nitride), and a hydrofluoric acid (DHF) solution is used to dissolve the hard mask (such as silicon nitride). Silicon nitride dissolves very slowly in the SC-1 solution, but dissolves nitrogen-based superconducting materials relatively quickly. Nitrogen-based superconducting materials are stable in the hydrofluoric acid (DHF) solution, but silicon nitride is soluble in the hydrofluoric acid (DHF) solution. Therefore, by utilizing the solubility of the superconducting material and the hard mask in the two solutions, the effect of separately etching the superconducting material or the hard mask can be achieved.

[0072] Through the above steps, the superconducting materials are sequentially deposited on the substrate according to the type of superconducting material to be integrated, and after each superconducting material is deposited, a hard mask is covered on it. After the target area range and other area ranges are determined, the hard mask can be used to realize regional integration of the superconducting material on the substrate. For example, if the superconducting material within the first target area range needs to be retained, the first hard mask within the first other area range of the first hard mask is etched away by combining photolithography and dry etching, that is, only the first hard mask within the first target area range is retained, and then wet etching is used, that is, etching is performed using an etching method that can only dissolve the superconducting material but not the hard mask. The etchant is used to etch away the first superconducting material exposed in the first other area, that is, only the first superconducting material is retained in the first target area. If other types of superconducting materials need to be integrated in other areas, the same deposition and etching method can be used. After completing the regional integration of all required superconducting materials, an etchant that can only dissolve the hard mask but not the superconducting material can be uniformly used to etch the hard mask, so as to remove the hard mask and only retain the superconducting material integrated on the substrate, thereby achieving the technical effect of regional integration of multiple superconducting materials on the same substrate, and further solving the technical problem of difficulty in integrating multiple superconducting materials on the same substrate.

[0073] Based on the above embodiments and optional embodiments, the present invention proposes an optional implementation manner, which is described below.

[0074] An optional embodiment of the present invention proposes a method for fabricating epitaxial nitride-based superconducting material integrated circuit components. A key aspect of this method is that it enables the area-selective integration of materials with varying thicknesses, chemical compositions, and processing conditions on the same wafer plane (i.e., the substrate referred to above). A silicon nitride layer serves as a hard mask and separation layer for the area-selective epitaxial growth of functionalized thin films, and an SC-1 solution is used to etch the functionalized thin films (i.e., the various superconducting materials described above). This method can serve as a foundation for constructing more complex quantum circuit structures.

[0075] In the manufacture of superconducting quantum circuits, it is often necessary to integrate materials of different thicknesses, different chemical compositions and different deposition conditions onto the same substrate plane. The integration needs to be done in such a way that the expected performance of each material is not affected during the process flow. In addition, for specific applications that require high-quality growth materials, it is hoped that this integration will enable epitaxial growth of multiple materials with a large thermal budget. This means that after etching each layer, the process should not affect the growth surface of subsequent materials. In other words, a key technical realization is the need to minimize the impact of the etching process on the wafer surface without the need for additional surface reconstruction processing to obtain a wafer surface structure suitable for epitaxial growth.

[0076] Based on the above considerations, an optional embodiment of the present invention provides an embodiment of integrating titanium nitride with different thicknesses on a substrate. Figure 2 FIG. 1 is a flow chart of integrating titanium nitride of different thicknesses on a substrate according to an embodiment of the present invention. Figure 2 As shown, the process includes the following steps:

[0077] Step S202, depositing a first titanium nitride layer on the substrate, wherein the first titanium nitride in the first target region is covered by the first silicon nitride in the first target region, wherein the thickness of the first titanium nitride in the first titanium nitride layer is a first thickness;

[0078] Step S204, depositing a second titanium nitride layer on the substrate having the first titanium nitride layer deposited thereon;

[0079] Step S206, covering the second titanium nitride with a second silicon nitride;

[0080] Step S208, etching the second silicon nitride and the second titanium nitride to obtain a first titanium nitride layer in which the second silicon nitride in the second target area covers the second titanium nitride in the second target area, wherein the thickness of the second titanium nitride in the second titanium nitride layer is the second thickness, and the first thickness is different from the second thickness.

[0081] By depositing titanium nitride of different thicknesses on the substrate as described above, since the first titanium nitride is covered by the first silicon nitride when preparing the second titanium nitride, the first titanium nitride will not be affected by the preparation of the second titanium nitride layer, that is, the first titanium nitride deposited on the substrate is effectively protected. Moreover, since the range of the first target area is different from the range of the second target area, that is, titanium nitride of different thicknesses is prepared in different areas of the same substrate, the entire process is not only efficient in operation, but also can effectively ensure the purity of titanium nitride of different thicknesses, thereby improving the precision of subsequent preparation of quantum devices.

[0082] As mentioned above, this optional embodiment provides a technology to achieve regional deposition and integration of nitrogen-based superconducting materials, and its feasibility is illustrated by taking the integration of titanium nitride (TiN) of different thicknesses as an example. Simply put, we choose silicon nitride (SiNx) as the hard mask material and SC-1 solution (i.e., a mixture of ammonia, hydrogen peroxide and water, with a composition ratio of 1:1:6) as the etchant. The reason for this choice is that, first, silicon nitride is stable below 1000°C, which provides a large thermal budget for all deposition steps. Secondly, the etching rate of silicon nitride in SC-1 solution is extremely slow (<1nm / min), so it can be used as an ideal mask layer and separation layer for different functional materials (i.e., superconducting materials of different thicknesses or properties). Finally, nitride-based superconducting materials are stable in dilute hydrofluoric acid (DHF), but the silicon nitride layer can be dissolved in the DHF solution. Therefore, the silicon nitride layer can be easily removed in the DHF solution. Since the etching selectivity of silicon nitride and nitride-based superconducting materials in SC-1 and DHF solutions is close to infinity, this combination can be repeated indefinitely to selectively integrate various superconducting materials on the same substrate plane.

[0083] In an alternative embodiment of the present invention, a process flow is described for integrating three different materials on the same substrate (e.g., sapphire substrate) to achieve a desired geometry. Figure 3 Figure 2 is a schematic diagram of an integrated circuit according to an optional embodiment of the present invention. The process begins with the deposition of a first layer, designated as sheet 1 (the first superconducting material). A silicon nitride layer is then deposited over sheet 1 as a hard mask. Before etching sheet 1, a pattern is first created in the hard mask layer using photolithography and dry etching to expose the areas of sheet 1 to be etched. Figure 4 This is a schematic diagram of wet etching according to an optional embodiment of the present invention. SC-1 solution is used to wet etch sheet 1. A silicon nitride mask layer remains on sheet 1 after the wet etching, completing the integration of the first superconducting layer. After the first layer is completed, the second layer of superconducting material (sheet 2) to be integrated is deposited on a wafer containing the patterned sheet 1 and the hard template. Figure 5Schematic diagram of photolithography according to an optional embodiment of the present invention. After the second superconducting layer (sheet 2) is deposited, another layer of silicon nitride mask is coated on the sheet 2, and the following steps are performed: Figure 5 The photolithographic patterning, dry etching, and wet etching shown are used to pattern sheet 2. It is important to note that the etching can be performed anywhere on the wafer, so it is essentially a region-selective deposition of each superconducting layer. Another important factor is that because the first layer, sheet 1, is protected by the remaining silicon nitride mask, the second wet etching has negligible effect on this layer. Figure 6 is a material deposition and patterning flow chart provided according to an optional embodiment of the present invention, according to Figure 6 The process shown is to realize the deposition and patterning of the third nitrogen-based superconducting material (sheet 3). For the final layer (sheet 3), the overall steps are consistent with the above process.

[0084] An optional embodiment of the present invention studies the integration of epitaxial TiN with different thicknesses on the same sapphire substrate to verify the feasibility of this inventive method. Figure 7a is a schematic diagram of an optical image provided according to an optional embodiment of the present invention, Figure 7a As can be seen in the figure, the test pattern of the 20nm thick TiN film is located in the center of the opening area, surrounded by a 100nm thick TiN layer. After two rounds of film deposition and etching, the sapphire surface after wet etching is first inspected. Figure 7b This is an atomic force microscope scan image provided according to an optional embodiment of the present invention. The sapphire surface maintains high quality, with clearly visible atomic steps. This demonstrates that the deposition and etching of the functional film does not affect the wafer surface quality. Therefore, this etching process can, in principle, be repeated multiple times to achieve regional deposition of high-quality nitrogen-based superconducting thin films of varying thickness, stoichiometry, and process conditions. Figure 7c Figure 2 is a schematic diagram of the surface of a TiN film according to an optional embodiment of the present invention. The TiN film is also very smooth, with a root mean square surface roughness of approximately 340 μm. To further examine the quality of the TiN film, X-ray diffraction was used to examine the crystalline quality of the TiN film at different thicknesses. Figure 7d This is an example of an X-ray scan result provided by an optional embodiment of the present invention. Figure 1 , Figure 7e This is an example of an X-ray scan result provided by an optional embodiment of the present invention. Figure 2As shown in the figure, the sharp diffraction peaks and Laue diffraction fringes of TiN under (111) diffraction conditions indicate that TiN films of different thicknesses deposited in different areas have achieved high crystallinity epitaxial growth. Through AFM and X-ray research, a conclusion can be reasonably drawn: this integration technology can be effectively used in applications that require the deposition of different types of thin films (such as thickness, chemical ratio, process conditions, etc.) on the same wafer plane. More importantly, this technology will not reduce the crystallinity, surface roughness and surface cleanliness of the material.

[0085] It should be noted that for the aforementioned method embodiments, for simplicity of description, they are all expressed as a series of action combinations. However, those skilled in the art should be aware that the present invention is not limited by the order of the actions described, because according to the present invention, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in this specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

[0086] Example 2

[0087] According to an embodiment of the present invention, a quantum device is further provided. The quantum device includes a circuit element formed of multiple superconducting materials, and the multiple superconducting materials are obtained by any of the above methods for preparing multiple superconducting material layers.

[0088] According to an embodiment of the present invention, the quantum device may be a Fluxonium qubit.

[0089] According to an embodiment of the present invention, a superconducting circuit is further provided, comprising the above-mentioned quantum device.

[0090] According to an embodiment of the present invention, a quantum chip is also provided, comprising the above-mentioned quantum device.

[0091] According to an embodiment of the present invention, a quantum computer is further provided. Figure 8 7 is a schematic diagram of a quantum computer provided according to an embodiment of the present invention. The quantum computer may be any quantum computer device in a quantum computer group. As shown in FIG7 , the quantum computer includes: a quantum memory 81 and the aforementioned quantum chip 82 .

[0092] It can be understood by those skilled in the art that Figure 8 The structure shown is for illustration only. Figure 8 It does not limit the structure of the above electronic device. For example, a quantum computer may also include Figure 8 More or fewer components than shown, or with Figure 8 Different configurations shown.

[0093] A person skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be completed by instructing the relevant preparation hardware through a program, and the program can be stored in a computer-readable storage medium, which may include: a flash drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, etc.

[0094] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the embodiments described above are merely illustrative, and the entire implementation process of the above embodiments still needs to be completed in conjunction with the control program unit of the computer, and the division of the units is only a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0095] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0096] In addition, the functional units in the various embodiments of the present invention may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0097] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk, etc. Various media that can store program codes.

[0098] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing multiple superconducting material layers, characterized in that: include: Depositing a first superconducting material layer of a first superconducting material in a first target area on the substrate, with the first hard mask in the first target area covering the first target area; depositing a second superconducting material on the substrate having the first superconducting material layer deposited thereon; covering the second superconducting material with a second hard mask; Etching the second hard mask and the second superconducting material to obtain a second superconducting material layer in which the second hard mask in the second target area covers the second superconducting material in the second target area; Among them, after etching the second hard mask and the second superconducting material to obtain a second superconducting material layer in which the second hard mask in the second target area covers the second superconducting material in the second target area, it also includes: using the same method as depositing the first superconducting material layer and the second superconducting material layer to deposit again to obtain a third superconducting material layer, and after the deposition is completed, removing the hard mask together with the first superconducting material layer and the second superconducting material layer.

2. The method according to claim 1, characterized in that The step of depositing a first superconducting material layer of a first superconducting material in a first target area on a substrate and covering the first target area with a first hard mask comprises: depositing the first superconducting material on the substrate; covering the first hard mask on the first superconducting material; determining a first target region on the substrate where the first superconducting material is to be left; The first hard mask in the first other area range in the first hard mask and the superconducting material in the first other area in the first superconducting material are gradually etched away to obtain the first superconducting material layer in which the first superconducting material in the first target area range is covered by the first hard mask in the first target area range, wherein the first other area range is an area range on the substrate other than the first target area range.

3. The method according to claim 1, characterized in that The etching process is performed on the second hard mask and the second superconducting material to obtain a second superconducting material layer in which the second hard mask in the second target area covers the second superconducting material in the second target area, comprising: The second hard mask in the second other area in the second hard mask and the superconducting material in the second other area in the second superconducting material are gradually etched away to obtain a second superconducting material layer, wherein the second other area range is the area range on the substrate excluding the second target area range, and the second superconducting material layer is the second superconducting material in the second target area covered by the second hard mask in the second target area.

4. The method according to claim 1, wherein After etching the second hard mask and the second superconducting material to obtain a second superconducting material layer in which the second hard mask in the second target area covers the second superconducting material in the second target area, the method further includes: The first hard mask on the first superconducting material layer and the second hard mask on the second superconducting material layer are etched away to obtain a first target superconducting device on the substrate.

5. The method according to claim 4, characterized in that The etching of the first hard mask on the first superconducting material layer and the second hard mask on the second superconducting material layer to obtain a first target superconducting device on the substrate includes: A hydrofluoric acid (DHF) solution is used to etch away the first hard mask on the first superconducting material layer and the second hard mask on the second superconducting material layer to obtain a first target superconducting device on the substrate.

6. The method according to claim 1, characterized in that After etching the second hard mask and the second superconducting material to obtain a second superconducting material layer in which the second hard mask in the second target area covers the second superconducting material in the second target area, the method further includes: Depositing a third superconducting material on the first superconducting material layer and on a first other region, wherein the first other region is a region on the substrate excluding the first target region; covering the third superconducting material with nitride as a third hard mask; determining a third target region on the substrate where the third superconducting material is to be left; The third hard mask and the third superconducting material are etched to obtain a third superconducting material layer in which the third superconducting material in the third target area is covered by the third hard mask in the third target area.

7. The method according to claim 6, characterized in that The etching process is performed on the third hard mask and the third superconducting material to obtain a third superconducting material layer in which the third hard mask in the third target area covers the third superconducting material in the third target area, comprising: The third hard mask in the third other area in the third hard mask and the superconducting material in the third other area in the third superconducting material are gradually etched away to obtain a third superconducting material layer in which the third superconducting material in the third target area is covered by the third hard mask in the third target area, wherein the third other area is an area on the substrate excluding the third target area.

8. The method according to claim 6, characterized in that After etching the third hard mask and the third superconducting material to obtain a third superconducting material layer in which the third hard mask in the third target area covers the third superconducting material in the third target area, the method further includes: The first hard mask on the first superconducting material layer, the second hard mask on the second superconducting material layer, and the third hard mask on the third superconducting material layer are etched away to obtain a second target superconducting device on the substrate.

9. The method according to claim 1, characterized in that The first hard mask is silicon nitride, and the second hard mask is silicon nitride.

10. The method according to claim 2, 3 or 7, characterized in that Etching away the first hard mask in the first other region of the first hard mask, etching away the second hard mask in the second other region of the second hard mask, and etching away the third hard mask in the third other region of the third hard mask by combining photolithography and dry etching; The superconducting material in the first other region of the first superconducting material is etched away by wet etching, the superconducting material in the second other region of the second superconducting material is etched away, and the superconducting material in the third other region of the third superconducting material is etched away.

11. The method according to claim 10, characterized in that The wet etching method uses an etchant of SC-1 solution.

12. A method for preparing multiple superconducting material layers, characterized in that: include: Depositing a first titanium nitride layer on the substrate, in which the first titanium nitride in the first target area is covered by the first silicon nitride in the first target area, wherein the thickness of the first titanium nitride in the first titanium nitride layer is a first thickness; depositing a second titanium nitride layer on the substrate having the first titanium nitride layer deposited thereon; covering the second titanium nitride with a second silicon nitride; Etching the second silicon nitride and the second titanium nitride to obtain a first titanium nitride layer in which the second silicon nitride in the second target region covers the second titanium nitride in the second target region, wherein the thickness of the second titanium nitride in the second titanium nitride layer is a second thickness, and the first thickness is different from the second thickness; Among them, after etching the second silicon nitride and the second titanium nitride to obtain a second titanium nitride layer in which the second silicon nitride in the second target area covers the second titanium nitride in the second target area, it also includes: using the same method as depositing the first titanium nitride layer and the second titanium nitride layer to deposit again to obtain a third titanium nitride layer, and after the deposition is completed, removing the silicon nitride together with the first titanium nitride layer and the second titanium nitride layer.

13. A quantum device, characterized in that: The quantum device includes circuit elements formed of multiple superconducting materials, and the multiple superconducting materials are obtained by the method for preparing multiple superconducting material layers according to any one of claims 1 to 12.

14. The quantum device according to claim 13, characterized in that The quantum device is a Fluxonium quantum bit.

15. A superconducting circuit, characterized in that: Comprising the quantum device according to claim 13 or 14.

16. A quantum chip, characterized in that: Comprising the quantum device according to claim 13 or 14.

17. A quantum computer, characterized in that include: A quantum memory and a quantum chip as claimed in claim 16.

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