Niobium-based Josephson junction etching method and semiconductor process equipment

Abstract

The invention provides a niobium-based Josephson junction etching method and semiconductor process equipment, relates to the technical field of semiconductors, and is designed for solving the problem of poor morphology perpendicularity of an etched side wall when upper niobium of a niobium-based Josephson junction is etched in the prior art. The niobium-based Josephson junction etching method comprises the following steps: providing a semiconductor device, wherein the semiconductor device comprises a photoresist layer, a first niobium layer, an aluminum oxide / aluminum layer, a second niobium layer and a substrate layer which are stacked in sequence; in the first etching step, the first niobium layer is etched with the photoresist layer as a mask, part of the first niobium layer is removed, and process gas comprises chlorine gas; in the second etching step, the first niobium layer is etched again with the photoresist layer as a mask, the remaining part of the first niobium layer is removed, and the process gas comprises fluorocarbon gas. According to the invention, the side wall of the first niobium layer has good verticality.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a niobium-based Josephson junction etching method and semiconductor process equipment. Background Art

[0002] The Josephson junction is a quantum electronic device based on superconductivity. It consists of two superconductors sandwiched by a very thin non-superconducting layer (usually an insulator or weak superconductor). The core principle of the Josephson junction is the quantum tunneling effect. Under low temperature conditions, the non-superconducting layer between the two superconductors allows superconducting electron pairs to pass through the quantum tunneling effect, forming an electric current without resistance.

[0003] In a niobium-based Josephson junction, the middle layer consists of a very thin layer of aluminum and an extremely thin aluminum oxide film formed by oxidation of its surface. Both above and below the middle layer are superconducting niobium. However, when etching the upper niobium layer, the related technology suffers from poor verticality of the etched sidewalls, increasing the risk of leakage in the superconducting tunnel. Summary of the Invention

[0004] The first object of the present invention is to provide a niobium-based Josephson junction etching method to solve the technical problem of poor verticality of the etching sidewall morphology when etching the upper niobium layer of the niobium-based Josephson junction in the related art.

[0005] The present invention provides a niobium-based Josephson junction etching method, comprising:

[0006] A semiconductor device is provided, comprising a photoresist layer, a first niobium layer, an aluminum oxide / aluminum layer, a second niobium layer, and a substrate layer stacked in sequence;

[0007] In a first etching step, the first niobium layer is etched using the photoresist layer as a mask to remove a portion of the first niobium layer; wherein the process gas includes chlorine; and

[0008] In a second etching step, the first niobium layer is etched again using the photoresist layer as a mask to remove the remaining portion of the first niobium layer; wherein the process gas includes a carbon-fluorine gas.

[0009] Furthermore, before the first etching step, the method further includes: a photoresist layer modification step to reduce the line width roughness of the photoresist layer.

[0010] Furthermore, in the first etching step, the process gas further includes boron trichloride, and the ratio of the chlorine gas to the boron trichloride is between 5:1 and 10:1.

[0011] Furthermore, in the first etching step, the flow rate of the chlorine gas is 150-250 sccm, the flow rate of the boron trichloride is 20-40 sccm; the process pressure is 4-6 mT; the upper RF power is 500-800W, and the bias power is 100-200W.

[0012] Furthermore, in the first etching step, the process gas further includes trifluoromethane, and the flow rate of the trifluoromethane is 0 to 10 sccm.

[0013] Furthermore, in the second etching step, the carbon fluoride gas is carbon tetrafluoride, and the flow rate of the carbon tetrafluoride is 150-200 sccm.

[0014] Furthermore, in the second etching step, the process pressure is 10-15 mT; the upper RF power is 500-800 W, and the bias power is 30-60 W.

[0015] Furthermore, in the photoresist layer modification step, the process gases include oxygen with a flow rate of 50-200 sccm and argon with a flow rate of 100-200 sccm; the process pressure is 4-8 mT; the upper RF power is 500-800 W, and the bias power is 30-80 W.

[0016] Furthermore, the ratio of the thickness of the first niobium layer removed in the first etching step to the thickness of the first niobium layer removed in the second etching step is 1:2 to 2:1.

[0017] The beneficial effects of the niobium-based Josephson junction etching method of the present invention are:

[0018] This etching method involves dividing the etching of the first Nb layer into two steps. In the first etching step, chlorine gas is introduced as the primary etching gas to etch the first niobium layer. Since chlorine gas only contains chlorine radicals, it only etches the first niobium layer. This prevents the formation of byproducts that accumulate on the sidewalls of both the photoresist layer and the first niobium layer during the etching process, thereby preventing the byproducts from blocking the etching process and causing the sidewall morphology of both layers to tilt. In this first etching step, the byproduct produced by the chlorine gas etching of the first niobium layer is niobium chloride, which is easily volatile and thus does not adhere to the sidewalls. After this first etching step, the sidewalls of the etched portions of the photoresist layer and the first niobium layer maintain good verticality. Therefore, during the continued etching of the remaining portion of the first niobium layer, the vertical sidewall morphology continues downward, thereby ensuring the verticality of the sidewalls of the resulting first niobium layer and, in turn, ensuring pattern transfer accuracy.

[0019] In the second etching step, by introducing a fluorocarbon gas, on the one hand, the fluorine radicals in the fluorocarbon gas can be utilized to participate in the etching of the remaining portion of the first niobium layer, thereby removing the remaining portion of the first niobium layer. On the other hand, the carbon radicals in the fluorocarbon gas can be utilized to form a carbon-containing sacrificial layer on the sidewalls of the first niobium layer, thereby protecting the sidewalls of the first niobium layer and reducing the indentation of the sidewalls of the first niobium layer caused by lateral etching, so that the sidewalls of the first niobium layer have better verticality.

[0020] In addition, since the portion of the first niobium layer to be etched in the second etching step is adjacent to the aluminum oxide / aluminum layer, by using carbon tetrafluoride as the main etching gas, after the portion of the first niobium layer not covered by the photoresist layer is completely etched, the carbon tetrafluoride can adhere to the surface of the exposed aluminum oxide / aluminum layer, thereby improving the etching selectivity for the aluminum oxide / aluminum layer without causing thickness loss of the aluminum oxide / aluminum layer. As a result, the second etching step can be stopped on the underlying aluminum oxide / aluminum layer to prevent breakdown of the aluminum oxide / aluminum layer.

[0021] The second object of the present invention is to provide a semiconductor process equipment to solve the technical problem of poor verticality of the etching sidewall morphology when etching the upper niobium layer of the niobium-based Josephson junction in the related art.

[0022] The semiconductor process equipment provided by the present invention includes a process chamber, an air inlet assembly, an upper electrode assembly, a lower electrode assembly and a controller. The controller includes at least one processor and at least one memory. The memory stores a computer program. When the computer program is executed by the processor, the niobium-based Josephson junction etching method as described above is implemented.

[0023] The beneficial effects brought about by the semiconductor process equipment of the present invention are:

[0024] The semiconductor process equipment can implement the above-mentioned niobium-based Josephson junction etching method. Accordingly, the semiconductor process equipment has all the advantages of the above-mentioned niobium-based Josephson junction etching method, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0026] Figure 1 A flow chart of a niobium-based Josephson junction etching method provided in an embodiment of the present invention;

[0027] Figure 2Cross-sectional views of the structure of a semiconductor device manufactured by a niobium-based Josephson junction etching method according to an embodiment of the present invention at various steps, wherein (a) is a schematic diagram of the device structure before etching the first niobium layer, (b) is a schematic diagram of the device structure after partially etching the first niobium layer, and (c) is a schematic diagram of the device structure after completely etching the first niobium layer.

[0028] Figure 3 A flow chart of another niobium-based Josephson junction etching method provided by an embodiment of the present invention;

[0029] Figure 4 A microscopic morphology image of a semiconductor device manufactured by the niobium-based Josephson junction etching method provided by an embodiment of the present invention;

[0030] Figure 5 A schematic structural diagram of semiconductor process equipment provided by an embodiment of the present invention.

[0031] Description of reference numerals:

[0032] 101 - photoresist layer; 102 - first niobium layer; 103 - aluminum oxide / aluminum layer; 104 - second niobium layer; 105 - substrate layer;

[0033] 100-plasma; 200-semiconductor process equipment; 20-process chamber; 20A-gas inlet assembly; 20B-upper electrode assembly; 20C-lower electrode assembly; 20D-exhaust assembly;

[0034] 21-RF coil; 22-wafer carrier; 23-upper RF power supply; 24-lower RF power supply; 25-upper matcher; 26-lower matcher. DETAILED DESCRIPTION

[0035] In a niobium-based Josephson junction, the middle layer consists of a very thin layer of aluminum and an extremely thin aluminum oxide film formed by oxidation of its surface. Both above and below this layer are superconducting niobium. When etching the upper niobium layer, the relevant technology uses 300 sccm of C4F8 (octafluorocyclobutane) as an etching gas into the process chamber, along with argon gas, to achieve a single-step etching of the upper niobium layer.

[0036] In the above etching method, on the one hand, the etching rate is slow and the production capacity cannot be guaranteed in mass production. On the other hand, a large amount of fluorine-based gas easily reacts with metal aluminum to generate AlF X The by-products adhere to the sidewalls and cannot be removed, resulting in poor verticality of the etched sidewall morphology and possible superconducting tunnel leakage.

[0037] Therefore, the purpose of the present invention is to provide a niobium-based Josephson junction etching method and semiconductor process equipment to at least solve the technical problem of poor verticality of the etching sidewall morphology when etching the upper niobium layer of the niobium-based Josephson junction in the related art.

[0038] In order to make the above-mentioned objects, features and advantages of the present invention more clearly understood, the following detailed description of the specific embodiments of the present invention is given in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0039] like Figure 1 As shown, this embodiment provides a niobium-based Josephson junction etching method, comprising:

[0040] Step S100: providing a semiconductor device, such as Figure 2 As shown in (a) of FIG. 1 , the semiconductor device includes a photoresist layer 101, a first niobium layer 102, an aluminum oxide / aluminum layer 103, a second niobium layer 104, and a base layer 105, which are stacked in sequence. The first niobium layer 102, the aluminum oxide / aluminum layer 103, and the second niobium layer 104 form a niobium-based Josephson junction.

[0041] In the semiconductor device, the base layer 105 can support the niobium-based Josephson junction to ensure the structural stability of the niobium-based Josephson junction. Specifically, the base layer 105 can be made of silicon dioxide, which can prevent short circuits and leakage currents by utilizing its electrical insulation properties.

[0042] Please continue to refer to Figure 2 In figure (a), above the Josephson junction is a photoresist layer 101. This layer, made of a relatively soft photoresist, forms a line pattern through photolithography processes such as development and fixing. During the Josephson junction fabrication process, photoresist layer 101 defines and protects the required areas, ensuring precise processing of the first niobium layer 102, the aluminum oxide / aluminum layer 103, and the second niobium layer 104.

[0043] Step S300: First etching step, using the photoresist layer 101 as a mask to etch the first niobium layer 102, removing part of the first niobium layer 102, and etching the resulting device structure as shown below: Figure 2 As shown in (b) in FIG; the process gas includes chlorine.

[0044] In the first etching step, chlorine gas is introduced as the main etching gas to etch the first niobium layer 102. Since chlorine gas contains only chlorine radicals, it only etches the first niobium layer 102. Therefore, the formation of byproducts that accumulate on the sidewalls of both the photoresist layer 101 and the first niobium layer 102 during the etching process is avoided. This prevents the byproducts from blocking the etching process and causing the sidewalls of both the photoresist layer 101 and the first niobium layer 102 to tilt. In this first etching step, the byproduct produced by the chlorine gas etching of the first niobium layer 102 is niobium chloride, which is easily volatile and thus does not adhere to the sidewalls.

[0045] After this first etching step, the sidewalls of the etched portions of the photoresist layer 101 and the first niobium layer 102 maintain good verticality. Therefore, during the etching of the remaining portion of the first niobium layer 102, the vertical sidewall morphology continues to propagate downward, thereby ensuring the verticality of the sidewalls of the final first niobium layer 102 and, in turn, the accuracy of pattern transfer.

[0046] In the first etching step, the process gas further includes boron trichloride, wherein the ratio of chlorine gas to boron trichloride is between 5:1 and 10:1.

[0047] By adding boron trichloride to the first etching step, the macromolecular properties of boron trichloride can be utilized to enhance its bombardment ability in the process chamber. In this way, in the first etching step, chlorine gas only participates in the chemical reaction to promote material removal, while the boron atoms dissociated from boron trichloride can physically bombard the surface of the first niobium layer 102, thereby enhancing the anisotropy of the etching, reducing the risk of the sidewalls of the first niobium layer 102 being undercut by chlorine gas, and further improving the verticality of the sidewalls.

[0048] By limiting the ratio of chlorine to boron trichloride within the above range, on the one hand, it is possible to avoid excessively high chemical etching rates due to excessive chlorine flow. At this time, due to too little boron trichloride flow, the anisotropy during the etching process will be reduced, not only failing to ensure the verticality of the sidewalls, but also making it difficult to control the etching depth and etching uniformity. On the other hand, it is possible to avoid excessively low chemical etching rates due to too little chlorine flow.

[0049] In the first etching step, the flow rate of chlorine gas is 150-250 sccm, and the flow rate of boron trichloride is 20-40 sccm. The flow rate is selected so that the ratio of chlorine gas to boron trichloride is within the above range, so that the first niobium layer 102 has a better etching rate and sidewall verticality.

[0050] Preferably, the ratio of chlorine to boron trichloride is 8:1.

[0051] In the first etching step, the process pressure is 4 to 6 mT.

[0052] By reducing the process pressure in the first etching step, the collision effect of the plasma can be reduced, thereby increasing its mean free path, strengthening the plasma bombardment, and enhancing the etching anisotropy to ensure the verticality of the sidewalls of the first niobium layer 102 after etching. At the same time, the process pressure can reduce the chemical etching efficiency of the photoresist layer 101.

[0053] In the first etching step, the upper RF power is 500-800W, and the bias power is 100-200W.

[0054] By using a relatively high top RF power in the first etch step, it helps promote the dissociation of chloride ions in chlorine gas and boron trichloride, thereby increasing the chemical etch rate, and it also helps ensure ignition stability. By maintaining the bias power within a high range, the energy of boron ion bombardment is enhanced, resulting in better verticality of the etched sidewalls.

[0055] In the first etching step, the process gas further includes trifluoromethane, wherein the flow rate of trifluoromethane is 0-10 sccm (excluding the value of 0).

[0056] By introducing trifluoromethane during the first etching step, a carbon-containing sacrificial layer can be formed and attached to the sidewalls of the first niobium layer 102 during the etching process of the first niobium layer 102, thereby protecting the sidewalls of the first niobium layer 102. By controlling the trifluoromethane flow rate within a range of 0 to 10 sccm, the formation of an excessively thick carbon-containing sacrificial layer attached to the sidewalls of the first niobium layer 102 due to an excessive trifluoromethane flow rate can be prevented, thereby reducing the etching rate.

[0057] In addition, the introduction of trifluoromethane can also form a carbon-containing sacrificial layer on the surface of the photoresist layer 101 to protect the photoresist layer 101 and increase the remaining amount of the photoresist layer 101, so that there is still a remaining amount of the photoresist layer 101 in the subsequent etching process, thereby improving the accuracy of pattern transfer.

[0058] As a specific embodiment, in the first etching step, the flow rate of chlorine gas may be 175 sccm, the flow rate of boron trichloride may be 25 sccm, and the flow rate of trifluoromethane may be 5 sccm; and the temperature of the electrostatic chuck may be 50°C.

[0059] Step S400: Second etching step, using the photoresist layer 101 as a mask to etch the first niobium layer 102 again, removing the remaining portion of the first niobium layer 102, and etching the resulting device structure as shown below: Figure 2 As shown in (c) in the figure, the process gas includes a carbon-fluorine gas.

[0060] In the second etching step, by introducing a fluorocarbon gas, on the one hand, the fluorine radicals in the fluorocarbon gas can be utilized to participate in the etching of the remaining portion of the first niobium layer 102, thereby removing the remaining portion of the first niobium layer 102. On the other hand, the carbon radicals in the fluorocarbon gas can be utilized to form a carbon-containing sacrificial layer on the sidewalls of the first niobium layer 102, thereby protecting the sidewalls of the first niobium layer 102 and reducing the indentation of the sidewalls of the first niobium layer 102 caused by lateral etching, thereby ensuring that the sidewalls of the first niobium layer 102 have better verticality.

[0061] Furthermore, since the portion of the first niobium layer 102 to be etched in the second etching step is adjacent to the aluminum oxide / aluminum layer 103, by using carbon tetrafluoride as the main etching gas, after the portion of the first niobium layer 102 not covering the photoresist layer 101 is completely etched, the carbon tetrafluoride can adhere to the surface of the exposed aluminum oxide / aluminum layer 103, thereby improving the etching selectivity for the aluminum oxide / aluminum layer 103 without causing thickness loss of the aluminum oxide / aluminum layer 103. As a result, the second etching step can be stopped on the underlying aluminum oxide / aluminum layer 103, preventing breakdown of the aluminum oxide / aluminum layer 103.

[0062] In the second etching step, the carbon fluoride gas is carbon tetrafluoride, wherein the flow rate of carbon tetrafluoride is 150-200 sccm.

[0063] By using carbon tetrafluoride to participate in etching the remaining portion of the first niobium layer 102, on the one hand, no more byproducts are generated in a low temperature environment, ensuring the cleanliness of the sidewall of the first niobium layer 102; on the other hand, more fluorine groups can also increase the etching rate.

[0064] By controlling the flow rate of CF4 within the above range, not only can the etching rate be reduced due to too small a CF4 flow rate, but also the etching rate can be reduced due to excessively thick carbon-containing byproducts generated due to too large a CF4 flow rate.

[0065] In the second etching step, the process pressure is 10-15 mT.

[0066] By making the process pressure of the second etching step higher than the process pressure of the first etching step, the plasma density in the second etching step can be enhanced to increase the etching rate of the remaining first niobium layer 102 .

[0067] In the second etching step, the upper RF power is 500-800W, and the bias power is 30-60W.

[0068] Using a relatively high upper RF power in the second etching step not only helps to promote the dissociation of fluorine ions in carbon tetrafluoride, thereby increasing the chemical etching rate, but also helps to ensure ignition stability. By maintaining the bias power within a low range, physical bombardment can be reduced, preventing the aluminum oxide / aluminum layer 103 from being penetrated by strong bombardment.

[0069] As a specific embodiment, in the second etching step, the flow rate of carbon tetrafluoride can be 200 sccm; and the temperature of the electrostatic chuck is 50°C.

[0070] In this embodiment, the ratio of the thickness of the first niobium layer 102 removed in the first etching step to the thickness of the first niobium layer 102 removed in the second etching step is 1:2 to 2:1.

[0071] This arrangement, on the one hand, prevents the first niobium layer 102 etched away in the first etching step from being too thick, thereby preventing the aluminum oxide / aluminum layer 103 from being damaged due to insufficient or no remaining first niobium layer 102 due to errors during mass production. On the other hand, a larger amount of the first niobium layer 102 can be etched in the first etching step, and the verticality of the sidewalls can be ensured by utilizing the chlorine gas in the first etching step to etch the first niobium layer 102.

[0072] Preferably, the ratio of the thickness of the first niobium layer 102 removed in the first etching step to the thickness of the first niobium layer 102 removed in the second etching step is 1:1, that is, in the first etching step, 1 / 2 of the first niobium layer 102 is etched away, and in the second etching step, the other 1 / 2 of the first niobium layer 102 is etched away.

[0073] like Figure 3 As shown, before the first etching step, the process further includes: step S200 , a modification step of the photoresist layer 101 , to reduce the line width roughness of the photoresist layer 101 .

[0074] After photolithography, the sidewall boundaries of the photoresist layer 101 are not completely smooth, but typically have an uneven or rough appearance. During the etching process, the pattern of the photoresist layer 101 is transferred downward layer by layer, and this rough appearance is gradually amplified, causing the sidewall boundaries to become uneven. In this step S200, by modifying the photoresist layer 101, the line width roughness of the photoresist layer 101 can be reduced, making the sidewalls of the photoresist layer 101 smoother, thereby reducing the adverse effects on the pattern transfer accuracy during the etching process, and ensuring that a more vertical sidewall appearance is obtained in the lower film layer when the pattern is transferred to the lower film layer.

[0075] In the step of modifying the photoresist layer 101 , the process gases include oxygen gas with a flow rate of 50-200 sccm and argon gas with a flow rate of 100-200 sccm.

[0076] During the above-mentioned modification step of the photoresist layer 101, oxygen acts as a chemical etchant, generating highly active oxygen free radicals in a plasma environment. These react chemically with residues on the surface of the photoresist layer 101, thereby cleaning the surface of the photoresist layer 101 and passivating or smoothing out the sharp protrusions on the surface of the photoresist layer 101, thereby reducing the line width roughness of the photoresist layer 101. Simultaneously, argon acts as a physical etchant, removing residues on the surface of the photoresist layer 101 through physical bombardment. It also slightly etches the sidewalls of the photoresist layer 101, improving the morphology and edge clarity of the photoresist layer 101 and trimming the edges of the photoresist layer 101, making the sidewalls of the photoresist layer 101 more vertical.

[0077] In the photoresist layer 101 modification step, the process pressure is 4-8 mT.

[0078] By lowering the process pressure during the modification step of the photoresist layer 101, the collision effect of the plasma can be reduced, thereby increasing its mean free path, strengthening the plasma bombardment, and enhancing the etching anisotropy, thereby achieving modification of the sidewalls of the photoresist layer 101. In addition, the process pressure can weaken the chemical etching efficiency of the photoresist layer 101, thereby reducing the consumption of the photoresist layer 101 and ensuring that there is still a portion of the photoresist layer 101 left in the subsequent etching process.

[0079] The upper RF power is 500~800W, and the bias power is 30~80W.

[0080] By using a relatively high top RF power during the modification step for the photoresist layer 101, it helps promote the dissociation of oxygen ions, thereby increasing the etching rate of the raised portions of the photoresist layer 101. It also helps ensure ignition stability. By keeping the bias power within a relatively low range, deformation of the photoresist layer 101 caused by physical bombardment can be reduced.

[0081] As a specific embodiment, in the step of modifying the photoresist layer 101 , the flow rate of oxygen gas may be 200 sccm; and the temperature of the electrostatic chuck may be 50-60° C.

[0082] like Figure 4 As shown, by adopting the above-mentioned niobium-based Josephson junction etching method, the sidewall morphology of the etched first niobium layer 102 is nearly 90° vertical, thereby ensuring superconducting performance.

[0083] like Figure 5 As shown, this embodiment also provides a semiconductor process equipment 200, including a process chamber 20, an air inlet assembly 20A, an upper electrode assembly 20B, a lower electrode assembly 20C and a controller, wherein the controller includes at least one processor and at least one memory, and a computer program is stored in the memory, and the computer program implements the above-mentioned etching method when executed by the processor.

[0084] The semiconductor process equipment 200 can implement the above etching method. Accordingly, the semiconductor process equipment 200 has all the advantages of the above etching method, which will not be described in detail here.

[0085] For example, the controller can be either a host computer or a slave computer. Specifically, the controller can control the opening of the valve of the gas inlet assembly 20A to introduce the corresponding process gas into the process chamber 20. The controller can also control the opening and closing of the valve of the gas inlet assembly 20A to control the flow rate of the process gas. The controller can also control the exhaust assembly 20D to exhaust the interior of the process chamber 20, for example, by controlling the valve opening of the exhaust assembly 20D or the speed of the exhaust pump, thereby controlling the pressure inside the process chamber 20 and exhausting reaction byproducts.

[0086] The upper electrode assembly 20B may include an RF coil 21, an upper RF power supply 23, and an upper matcher 25. The controller is further configured to control the upper RF power supply 23 to provide upper RF power to the RF coil 21 via the upper matcher 25, so that the RF coil 21 excites the process gas inside the process chamber 20 to generate plasma 100.

[0087] The lower electrode assembly 20C may include a wafer carrier 22, a lower RF power supply 24, and a lower matcher 26. The controller is further configured to control the lower RF power supply 24 to provide lower RF power to the wafer carrier 22 via the lower matcher 26 to provide an RF bias. The wafer carrier 22 may be an electrostatic chuck, a mechanical chuck, or a vacuum chuck.

[0088] Specifically, the semiconductor process equipment 200 according to the embodiment of the present application may be an ICP (Inductively Coupled Plasma) etcher.

[0089] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

[0090] Finally, it should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprises" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article, or device that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, article, or device that includes the element.

[0091] In the above embodiments, the descriptions of directions such as “upper”, “lower”, and “side” are all based on the drawings.

[0092] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A niobium-based Josephson junction etching method, characterized in that: include: A semiconductor device is provided, comprising a photoresist layer (101), a first niobium layer (102), an aluminum oxide / aluminum layer (103), a second niobium layer (104), and a base layer (105) stacked in sequence; In a first etching step, the first niobium layer (102) is etched using the photoresist layer (101) as a mask, removing a portion of the first niobium layer (102); wherein the process gas comprises chlorine; and In a second etching step, the first niobium layer (102) is etched again using the photoresist layer (101) as a mask to remove the remaining portion of the first niobium layer (102); wherein the process gas includes a carbon-fluorine gas.

2. The niobium-based Josephson junction etching method according to claim 1, characterized in that: Before the first etching step, the method further includes: a photoresist layer (101) modification step to reduce the line width roughness of the photoresist layer (101).

3. The niobium-based Josephson junction etching method according to claim 1, characterized in that: In the first etching step, the process gas further includes boron trichloride, and the ratio of the chlorine gas to the boron trichloride is between 5:1 and 10:

1.

4. The niobium-based Josephson junction etching method according to claim 3, characterized in that: In the first etching step, the flow rate of the chlorine gas is 150-250 sccm, the flow rate of the boron trichloride is 20-40 sccm; the process pressure is 4-6 mT; the upper RF power is 500-800W, and the bias power is 100-200W.

5. The niobium-based Josephson junction etching method according to claim 1, characterized in that: In the first etching step, the process gas further includes trifluoromethane, and the flow rate of the trifluoromethane is 0-10 sccm.

6. The niobium-based Josephson junction etching method according to claim 1, characterized in that: In the second etching step, the carbon fluoride gas is carbon tetrafluoride, and the flow rate of the carbon tetrafluoride is 150-200 sccm.

7. The niobium-based Josephson junction etching method according to claim 1, characterized in that: In the second etching step, the process pressure is 10-15 mT; the upper RF power is 500-800 W, and the bias power is 30-60 W.

8. The niobium-based Josephson junction etching method according to claim 2, characterized in that: In the photoresist layer (101) modification step, the process gas includes oxygen with a flow rate of 50-200 sccm and argon with a flow rate of 100-200 sccm; the process pressure is 4-8 mt; the upper radio frequency power is 500-800 W, and the bias power is 30-80 W.

9. The niobium-based Josephson junction etching method according to any one of claims 1 to 8, characterized in that: The ratio of the thickness of the first niobium layer (102) removed in the first etching step to the thickness of the first niobium layer (102) removed in the second etching step is 1:2 to 2:

1.

10. A semiconductor process equipment comprising a process chamber (20), an air inlet assembly (20A), an upper electrode assembly (20B), a lower electrode assembly (20C) and a controller, characterized in that: The controller includes at least one processor and at least one memory, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the niobium-based Josephson junction etching method according to any one of claims 1 to 9 is implemented.

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