Method and system for removing oxide layer on surface of superconducting device

Abstract

The invention relates to the technical field of superconducting devices, and discloses a method and a system for removing an oxide layer on the surface of a superconducting device. The scanning device determines an abnormal oxidation region, applies voltage to the region until the oxide layer is punctured, adjusts the voltage to detect the region to obtain a first resistance after the region is punctured, collects the thickness of the residual oxide layer in the region when the first resistance meets a condition, and sends the first resistance to the scanning device when the thickness is greater than a first thickness threshold value; and cleaning the region again by using laser until the thickness is not greater than the first thickness threshold value, pressurizing the voltage, returning to apply the voltage to the region until the residual thickness is less than the second thickness threshold value, detecting the second resistance of the region after breakdown, and completing oxide layer removal judgment according to the first resistance and the second resistance. Through two oxide layer removal modes of voltage and laser, and in combination with detection of resistance, thickness and the like, cyclic switching of the two modes is realized, so that the removal completeness of the oxide layer on the surface of the superconducting device is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of superconducting devices, and in particular to a method and system for removing an oxide layer on the surface of a superconducting device. Background Art

[0002] Superconducting devices hold enormous potential for applications in energy transmission, quantum computing, medical imaging, and other fields. However, when exposed to air, undergoing certain processes, or exposed to complex environments, an oxide layer easily forms on the surface of these devices. This oxide layer can significantly affect their performance, increasing resistance, reducing critical current density, and destabilizing the superconducting state, thereby limiting their practical application and reliability.

[0003] At present, a single oxide layer removal method has certain limitations. For example, although laser oxide layer removal technology has the advantages of high precision, high energy density, and easy control, it may not be able to completely remove some oxide layers with special structures or distributions, and may cause certain thermal effects on the surface of the superconducting device during the treatment process; and the four-probe high-voltage oxide layer removal method can use the action of a high-voltage electric field to remove the oxide layer, but for thicker or tightly bound oxide layers, the removal efficiency may be lower.

[0004] In the actual oxide layer removal process, due to the lack of effective real-time monitoring methods, the device is easily damaged during the process of using the above-mentioned methods to remove the oxide layer. It is also impossible to accurately evaluate the effect of oxide layer removal, and it is not known what impact the removal of the oxide layer has on the performance of the superconducting device.

[0005] Therefore, how to optimize the removal process of the oxide layer on the device surface to improve the removal effect has become an urgent problem to be solved. Summary of the Invention

[0006] The embodiment of the present invention provides a method and system for removing the oxide layer on the surface of a superconducting device, so as to solve the problem of how to optimize the removal process of the oxide layer on the surface of the device to improve the removal effect.

[0007] In a first aspect, the present invention provides a method for removing an oxide layer on the surface of a superconducting device, comprising:

[0008] Scanning the surface of the superconducting device to be processed to determine an abnormal oxidation region, and applying a first voltage value to the abnormal oxidation region until the oxide layer in the abnormal oxidation region is broken down;

[0009] adjusting the first voltage value to a second voltage value to detect the abnormally oxidized region, obtaining a first resistance state of the abnormally oxidized region after breakdown, and if the first resistance state does not meet a first preset condition, collecting a residual thickness of an oxide layer remaining in the abnormally oxidized region in real time, and the second voltage value is less than the first voltage value;

[0010] When the residual thickness is greater than a first thickness threshold, the abnormally oxidized region is cleaned using a laser until the residual thickness is no greater than the first thickness threshold, and the first voltage value is pressurized to obtain the pressurized first voltage value;

[0011] Using the first voltage value after pressurization as the first voltage value, returning to the step of applying the first voltage value to the abnormally oxidized region until the residual thickness is less than a second thickness threshold, and detecting a second resistance state of the abnormally oxidized region after breakdown;

[0012] A qualification determination parameter is determined according to the first resistance state and the second resistance state, and when the qualification determination parameter meets a second preset condition, it is determined that the oxide layer removal is completed.

[0013] Optionally, before collecting the residual thickness of the oxide layer remaining in the abnormal oxidation region in real time if the first resistance state does not satisfy the first preset condition, the method further includes:

[0014] detecting whether the first resistance state satisfies a first preset condition;

[0015] If the first resistance state satisfies the first preset condition, detecting a second resistance state after the abnormal oxidation region is broken down is performed.

[0016] Optionally, if the first resistance state is a resistance value, detecting whether the first resistance state satisfies a first preset condition includes:

[0017] detecting whether a resistance value corresponding to the first resistance state is less than a resistance threshold, and determining that the first resistance state satisfies the first preset condition if the resistance value corresponding to the first resistance state is less than the resistance threshold;

[0018] If the resistance value corresponding to the first resistance state is not less than the resistance threshold, it is determined that the first resistance state does not meet the first preset condition.

[0019] Optionally, it also includes:

[0020] Obtaining the overcurrent of the superconducting device to be processed;

[0021] The applying a first voltage value to the abnormal oxidation region includes:

[0022] A first voltage value is applied to the abnormal oxidation region, and a current during the application is controlled to be smaller than the overcurrent.

[0023] Optionally, before detecting the second resistance state of the abnormally oxidized region after breakdown, the method further includes:

[0024] detecting the surface roughness of the abnormally oxidized area;

[0025] If the surface roughness is less than the roughness threshold, detecting the second resistance state of the abnormally oxidized region after breakdown is performed;

[0026] If the surface roughness is not less than the roughness threshold, the method returns to executing the step of applying the first voltage value to the abnormal oxidation region.

[0027] Optionally, the first resistance state is a first resistance value, the second resistance state is a second resistance value, and determining the qualification determination parameter according to the first resistance state and the second resistance state includes:

[0028] Calculating a difference between the first resistance value and the second resistance value to obtain a resistance difference value, and comparing the resistance difference value with the first resistance value to obtain a ratio as a qualification determination parameter;

[0029] detecting whether the qualification determination parameter is less than a ratio threshold, and if the qualification determination parameter is less than the ratio threshold, determining that the qualification determination parameter satisfies a second preset condition;

[0030] If the qualification determination parameter is not less than the ratio threshold, it is determined that the qualification determination parameter does not meet the second preset condition.

[0031] Optionally, the step of applying a first voltage value to the abnormally oxidized region until the oxide layer in the abnormally oxidized region is broken down further comprises:

[0032] Recording a breakdown voltage of the oxide layer in the abnormally oxidized region;

[0033] After the first voltage value is pressurized to obtain the pressurized first voltage value, the method further includes:

[0034] detecting whether the first voltage value after the pressurization exceeds the breakdown voltage;

[0035] If the first voltage value after pressurization exceeds the breakdown voltage, the first voltage value after pressurization is restored to the voltage value before pressurization.

[0036] Optionally, before performing surface scanning on the superconducting device to be processed to determine the abnormal oxidation area, the method further includes:

[0037] Obtaining the device type of the superconducting device to be processed, and detecting the initial thickness of the oxide layer on the surface of the superconducting device to be processed;

[0038] Determining whether to use a voltage removal technique or a laser removal technique to remove the oxide layer according to the device type and the initial thickness;

[0039] If it is determined to use the voltage removal technology, performing the surface scanning on the superconducting device to be processed to determine the abnormal oxidation area;

[0040] If it is determined to use the laser removal technology, before performing the surface scanning of the superconducting device to be processed and determining the abnormal oxidation area, the laser parameters are adjusted according to the initial thickness and the oxide layer of the superconducting device to be processed is removed using the laser parameters.

[0041] Optionally, after removing the oxide layer of the superconducting device to be processed using the laser parameters, the method further includes:

[0042] The surface of the superconducting device to be processed is scanned to determine abnormal oxidation areas.

[0043] In a second aspect, the present invention provides a system for removing an oxide layer on the surface of a superconducting device, the system comprising: a voltage probe device, a laser device, an ellipsometer monitoring device, and a control device, wherein the control device is connected to the voltage probe device, the laser device, and the ellipsometer monitoring device;

[0044] Scanning the surface of the superconducting device to be processed using the voltage probe device to determine an abnormal oxidation region, and applying a first voltage value to the abnormal oxidation region until the oxide layer in the abnormal oxidation region is broken down;

[0045] Using the voltage probe device to adjust the first voltage value to a second voltage value to detect the abnormally oxidized region, obtaining a first resistance state of the abnormally oxidized region after breakdown, and if the first resistance state does not meet a first preset condition, using the ellipsometer monitoring device to collect a residual thickness of the residual oxide layer in the abnormally oxidized region in real time, and the second voltage value is less than the first voltage value;

[0046] The laser device is used to clean the abnormally oxidized area using a laser when the residual thickness is greater than a first thickness threshold, and after the residual thickness is no greater than the first thickness threshold, pressurize the first voltage value in the voltage probe device to obtain the pressurized first voltage value;

[0047] The voltage probe device is configured to use the first voltage value after pressurization as the first voltage value, return to applying the first voltage value at the abnormally oxidized region until the residual thickness is less than a second thickness threshold, and detect a second resistance state of the abnormally oxidized region after breakdown;

[0048] The control device is used to determine a qualification judgment parameter according to the first resistance state and the second resistance state, and determine that the oxide layer removal is completed when the qualification judgment parameter meets a second preset condition.

[0049] Compared with the prior art, the present invention achieves the following technical effects: the present invention performs surface scanning on a superconducting device to be processed to determine an abnormally oxidized region, applies a first voltage value to the abnormally oxidized region until the oxide layer in the abnormally oxidized region is broken down, adjusts the first voltage value to a second voltage value to detect the abnormally oxidized region, and obtains a first resistance state of the abnormally oxidized region after breakdown. If the first resistance state does not meet a first preset condition, the residual thickness of the oxide layer remaining in the abnormally oxidized region is collected in real time. The second voltage value is less than the first voltage value. When the residual thickness is greater than a first thickness threshold, the abnormally oxidized region is cleaned using a laser until the residual thickness is no greater than the first thickness threshold. The first voltage value is then pressurized to obtain a first voltage value after pressurization. The first voltage value after pressurization is used as the first voltage value. The process of applying the first voltage value to the abnormally oxidized region until the residual thickness is less than a second thickness threshold is returned to, and a second resistance state of the abnormally oxidized region after breakdown is detected. A qualification determination parameter is determined based on the first resistance state and the second resistance state. When the qualification determination parameter meets a second preset condition, the oxide layer removal is determined to be complete. By using voltage and laser to remove the oxide layer, combined with the detection of resistance, thickness, etc., the two methods can be cyclically switched to improve the completeness of removing the oxide layer on the surface of the superconducting device. In addition, the switching between the two methods can effectively avoid damage to the superconducting device during the removal process. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0051] Figure 1 This is a schematic structural diagram of a system for removing an oxide layer on a surface of a superconducting device provided in a first embodiment of the present invention;

[0052] Figure 2 This is a schematic flow chart of a method for removing an oxide layer on the surface of a superconducting device provided in the second embodiment of the present invention;

[0053] Among them, 1 is the processing platform; 2 is the superconducting device; 3 is the ellipsometer monitoring equipment; 4 is the voltage probe equipment; 5 is the semiconductor parameter analyzer; 6 is the laser equipment; 7 is the display screen; and 8 is the control equipment. DETAILED DESCRIPTION

[0054] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. 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.

[0055] like Figure 1 FIG. 1 is a schematic diagram of a system for removing oxide layers from a superconducting device according to a first embodiment of the present invention, wherein the system comprises an ellipsometer monitoring device 3, a voltage probe device 4, a laser device 6, and a control device 8, wherein the control device 8 is connected to the voltage probe device 4, the laser device 6, and the ellipsometer monitoring device 3. Figure 2 Also shown are a processing platform 1 for sample operation, a superconducting device 2, a semiconductor parameter analyzer 5, and a computer display screen 7. The processing platform 1 for sample operation is used to carry the superconducting device 2, ensure that the device is fixed and stable during the processing process, and support strategies for devices of various sizes of wafers; the semiconductor parameter analyzer 5 is essentially a part of the voltage probe device 4, and the semiconductor parameter analyzer 5 is connected to the control system 8 to accurately control the high-voltage excitation and duration, and collect voltage-current-resistance data in real time to accurately realize the output and input of the voltage probe device 4; the computer display screen is connected to the control device 8 to realize data display, image display, and parameter input debugging between various devices.

[0056] The ellipsometer device 3 is an optical measuring instrument used to detect film thickness, optical constants and material microstructure. By measuring the change in the polarization state of light before and after reflection on the device surface, the optical constants and structural information of the material are obtained. During the oxide layer removal process, the ellipsometer device 3 emits polarized light and measures the change in the polarization state of the reflected light, and obtains information such as the thickness, optical constants and microstructure of the film layer on the device surface in real time. It can monitor the thickness change and optical property change of the oxide layer in real time, and provide a basis for the optimization of the oxide layer removal process. Therefore, in the process of oxide layer removal, the ellipsometer device 3 emits polarized light and measures the change in the polarization state of the reflected light, and obtains information such as the thickness, optical constants and microstructure of the film layer on the device surface in real time. Figure 2 The figure shows the transmitting end and the receiving end of the ellipsometer device 3. The two ends correspond to each other, one sends the light signal and the other receives the light signal, and then the result is obtained through signal analysis.

[0057] The voltage probe device 4 of the present invention can adopt a four-probe high-voltage device. The four-probe method is a commonly used electrical testing technology for thin-film devices, which is often used to measure the resistivity, conductivity and other electrical properties of materials. In the present invention, it is used to remove the oxide layer by applying high voltage to the safe test area of ​​the device under test, and using four probes to accurately flow current through the device safe area, so that the oxide layer undergoes physical or chemical changes under the action of the high-voltage electric field, thereby achieving the removal of the oxide layer. High voltage may cause ions in the oxide layer to migrate, chemical bonds to break, etc., prompting the oxide layer to peel off from the surface of the device.

[0058] Laser device 6 utilizes the principle of laser removal of oxide layers, namely, the thermal effect of the interaction between laser and material. When a high-energy laser beam is irradiated onto the surface of a superconducting device, the laser energy is absorbed by the oxide layer and converted into heat, rapidly heating the oxide layer to its melting or boiling point, thereby removing the oxide layer. For superconducting devices, laser parameters must be optimized to avoid adverse effects on superconducting performance. Laser device 6 may include a pulsed laser generator capable of generating a laser beam with a specific wavelength, pulse energy, pulse width, and repetition rate, and a laser focusing and scanning device for focusing the laser beam on the oxide layer on the device surface and scanning it along a preset path.

[0059] The control device 8 can essentially be a processor, specifically a computer device, etc., which can receive data from the voltage probe device 4, the laser device 6 and the ellipsometer monitoring device 3, perform comprehensive analysis and processing, and adjust the voltage parameters, laser parameters and scanning path according to the analysis results to achieve automatic control and real-time optimization of the oxide layer removal process.

[0060] Specifically, during the control process, the control process is as follows:

[0061] Scanning the surface of the superconducting device to be processed using the voltage probe device to determine an abnormal oxidation region, and applying a first voltage value to the abnormal oxidation region until the oxide layer in the abnormal oxidation region is broken down;

[0062] Using the voltage probe device to adjust the first voltage value to a second voltage value to detect the abnormally oxidized region, obtaining a first resistance state of the abnormally oxidized region after breakdown, and if the first resistance state does not meet a first preset condition, using the ellipsometer monitoring device to collect a residual thickness of the residual oxide layer in the abnormally oxidized region in real time, and the second voltage value is less than the first voltage value;

[0063] The laser device is used to clean the abnormally oxidized area using a laser when the residual thickness is greater than a first thickness threshold, and after the residual thickness is no greater than the first thickness threshold, pressurize the first voltage value in the voltage probe device to obtain the pressurized first voltage value;

[0064] The voltage probe device is configured to use the first voltage value after pressurization as the first voltage value, return to applying the first voltage value at the abnormally oxidized region until the residual thickness is less than a second thickness threshold, and detect a second resistance state of the abnormally oxidized region after breakdown;

[0065] The control device is used to determine a qualification judgment parameter according to the first resistance state and the second resistance state, and determine that the oxide layer removal is completed when the qualification judgment parameter meets a second preset condition.

[0066] In an embodiment of the present invention, a surface scan of a superconducting device to be processed is performed to determine an abnormally oxidized region. A first voltage value is applied to the abnormally oxidized region until the oxide layer in the abnormally oxidized region is broken down. The first voltage value is adjusted to a second voltage value to detect the abnormally oxidized region to obtain a first resistance state of the abnormally oxidized region after breakdown. If the first resistance state does not meet a first preset condition, the residual thickness of the oxide layer remaining in the abnormally oxidized region is collected in real time. The second voltage value is less than the first voltage value. When the residual thickness is greater than a first thickness threshold, the abnormally oxidized region is cleaned using a laser until the residual thickness is no greater than the first thickness threshold. The first voltage value is then pressurized to obtain a first voltage value after pressurization. The first voltage value after pressurization is used as the first voltage value. The process of applying the first voltage value to the abnormally oxidized region until the residual thickness is less than a second thickness threshold is then performed. A second resistance state of the abnormally oxidized region after breakdown is detected. A qualification determination parameter is determined based on the first and second resistance states. When the qualification determination parameter meets a second preset condition, the oxide layer removal is determined to be complete. By using voltage and laser to remove the oxide layer, combined with the detection of resistance, thickness, etc., the two methods can be cyclically switched to improve the completeness of removing the oxide layer on the surface of the superconducting device. In addition, the switching between the two methods can effectively avoid damage to the superconducting device during the removal process.

[0067] like Figure 2 FIG. 1 is a flow chart of a method for removing an oxide layer on the surface of a superconducting device according to a second embodiment of the present invention. The method for removing an oxide layer on the surface of a superconducting device may include the following steps:

[0068] Step S201 : Scan the surface of the superconducting device to be processed to determine an abnormal oxidation region, and apply a first voltage value to the abnormal oxidation region until the oxide layer in the abnormal oxidation region is broken through.

[0069] Among them, the surface scanning of the superconducting device can be carried out using an ellipsometer monitoring device, a voltage probe device, etc., that is, the surface scanning of the device can be achieved by using any device that can achieve surface scanning, and the present invention does not limit this here.

[0070] In step S201 of the present invention, the surface scan to identify abnormally oxidized regions is performed using a voltage probe device. The specific function of the voltage probe device will be described later. The voltage probe device can be adjusted to scan and map the initial resistance distribution of the superconducting device surface using a low voltage (e.g., 0.1V), thereby marking abnormally high resistance points (e.g., resistance values ​​greater than 1000Ω). A single abnormally high resistance point is then selected as an abnormally oxidized region, and a high voltage (i.e., a first voltage value) is applied to the abnormally oxidized region. The duration of the voltage application can be set as needed, thereby breaking down the oxide layer at that location. The high voltage value can be selected from any value between 3V and 20V.

[0071] Since the breakdown voltage that superconducting devices can withstand does not reach hundreds of volts or thousands of volts, the high voltage and low voltage defined in the present invention are relative to each other, rather than the conventional high and low voltages.

[0072] Optionally, the method for removing the oxide layer on the surface of a superconducting device further comprises:

[0073] Obtaining the overcurrent of the superconducting device to be processed;

[0074] The applying a first voltage value to the abnormal oxidation region includes:

[0075] A first voltage value is applied to the abnormal oxidation region, and a current during the application is controlled to be smaller than the overcurrent.

[0076] Among them, when applying voltage to the abnormal oxidation area, it is necessary to limit the current during application. The maximum limit of this current is the overcurrent of the superconducting device, that is, the current when applying voltage cannot exceed the overcurrent, for example, the current does not exceed 10mA, so as to avoid overcurrent damage to the superconducting device.

[0077] Optionally, before performing surface scanning on the superconducting device to be processed to determine the abnormal oxidation area, the method further includes:

[0078] Obtaining the device type of the superconducting device to be processed, and detecting the initial thickness of the oxide layer on the surface of the superconducting device to be processed;

[0079] Determining whether to use a voltage removal technique or a laser removal technique to remove the oxide layer according to the device type and the initial thickness;

[0080] If it is determined to use the voltage removal technology, performing the surface scanning on the superconducting device to be processed to determine the abnormal oxidation area;

[0081] If it is determined to use the laser removal technology, before performing the surface scanning of the superconducting device to be processed and determining the abnormal oxidation area, the laser parameters are adjusted according to the initial thickness and the oxide layer of the superconducting device to be processed is removed using the laser parameters.

[0082] In this embodiment, the superconducting device may be judged first, and the voltage removal technology or the laser removal technology may be selected to remove the oxide layer according to the device type and the initial thickness of the surface oxide layer.

[0083] Voltage removal technology involves applying voltage to abnormally oxidized areas to cause ions in the oxide layer to migrate, break chemical bonds, and so on, thereby breaking through the oxide layer and causing the oxide layer to peel off from the device surface. Laser removal technology involves irradiating the oxide layer with a laser, causing the oxide layer to rapidly heat up and reach its melting point or boiling point, thereby achieving oxide layer removal.

[0084] For superconducting devices that are initially thick and can be removed at high temperatures, laser removal can be used directly. For superconducting devices that are initially thin and cannot be removed at high temperatures, voltage removal can be used. By making the above assessments and selections, the most effective removal method can be selected, thereby improving removal efficiency.

[0085] For example, the removal method is selected based on the device type (superconducting / conventional electronic device) and the state of the oxide layer (thickness, uniformity). The steps are as follows:

[0086] 1. Preprocessing and evaluation

[0087] Ellipsometer was used to measure the initial thickness and optical constants of the oxide layer on the device surface;

[0088] Select the removal method based on the device type (superconducting / ordinary electronic device) and the state of the oxide layer (thickness, uniformity):

[0089] For ordinary electronic devices or devices with thin oxide film layers (<0.5 um), a four-probe high-voltage system is preferred for removal. For superconducting devices and other devices with the risk of electrostatic ablation or severe local oxidation, a laser removal system is preferred.

[0090] 2. Four-probe high-voltage removal (applicable to common electronic devices or devices with thin oxide films (<0.5 um))

[0091] Four probes contact the device surface and apply an optimized high-voltage signal (5-20V, the specific voltage and duration are adjusted according to the material and oxide layer characteristics). Current flows through the oxide film layer between the two probes, forming a strong electric field inside it and inducing defects in the oxide layer to produce an avalanche effect, destroying its structure and causing a sudden drop in resistance. During this process, the resistance change is monitored in real time, and the system stops when the resistance stabilizes to the expected value.

[0092] 3. Laser removal (applicable to superconducting devices or severe oxidation)

[0093] The laser parameters (wavelength, energy, pulse width, and frequency) are adjusted based on the surface oxide film thickness data obtained by the ellipsometer. The energy is increased in thick areas of the oxide layer and reduced in thin areas. The laser is focused and scanned across the oxide layer to vaporize and remove it. During the process, the film thickness parameters and effects of the ellipsometer are monitored in real time.

[0094] 4. Ellipsometer-assisted testing and effect verification

[0095] After removal, the surface thickness, optical constants and microstructure are measured again using an ellipsometer; the performance is comprehensively evaluated based on the resistance data from the four-probe low-voltage constant-voltage test. If the standards are not met, the process is repeated.

[0096] Optionally, after removing the oxide layer of the superconducting device to be processed using the laser parameters, the method further includes:

[0097] The surface of the superconducting device to be processed is scanned to determine abnormal oxidation areas.

[0098] Among them, after using laser to remove the superconducting device, voltage removal technology can also be used to intervene to avoid high temperature burning of the surface of the superconducting device and to improve the integrity of the surface removal.

[0099] In step S202, the first voltage value is adjusted to a second voltage value to detect the abnormal oxidation area, and a first resistance state of the abnormal oxidation area after breakdown is obtained. If the first resistance state does not meet a first preset condition, the residual thickness of the residual oxide layer in the abnormal oxidation area is collected in real time.

[0100] The second voltage value is lower than the first voltage value, indicating that the first voltage value is a high voltage and the second voltage value is a low voltage. Here, the voltage of the device is lowered to detect the resistance of the abnormally oxidized region after breakdown (i.e., the first resistance state). The second voltage value can be 0.1V, that is, the device resistance is detected by lowering the voltage from the first voltage value to the second voltage value to obtain the first resistance state.

[0101] If the resistance is less than a certain value, it indicates that the surface oxide layer has been removed. If the resistance is not less than the value, it indicates that the surface oxide layer has not been completely removed and the oxide layer needs to be removed again in the abnormally oxidized area.

[0102] The residual thickness can be detected by the ellipsometer device, so that the removal method can be switched according to the residual thickness. During the entire process of removing the oxide layer, the ellipsometer device can detect the thickness of the surface oxide layer throughout the process. Of course, the thickness of the surface oxide layer can also be collected when the detection is triggered.

[0103] Optionally, before collecting the residual thickness of the oxide layer remaining in the abnormal oxidation region in real time if the first resistance state does not satisfy the first preset condition, the method further includes:

[0104] detecting whether the first resistance state satisfies a first preset condition;

[0105] If the first resistance state satisfies the first preset condition, detecting a second resistance state after the abnormal oxidation region is broken down is performed.

[0106] Among them, if it is detected that the first resistance state meets the first preset condition, for example, the resistance value is less than a certain value, the subsequent step S204 is executed to detect the second resistance state after the abnormal oxidation area is broken down, that is, a jump is achieved, and there is no need to execute step S203, thereby improving the judgment efficiency.

[0107] Optionally, if the first resistance state is a resistance value, detecting whether the first resistance state satisfies a first preset condition includes:

[0108] detecting whether a resistance value corresponding to the first resistance state is less than a resistance threshold, and determining that the first resistance state satisfies the first preset condition if the resistance value corresponding to the first resistance state is less than the resistance threshold;

[0109] If the resistance value corresponding to the first resistance state is not less than the resistance threshold, it is determined that the first resistance state does not meet the first preset condition.

[0110] Among them, the first resistance state is taken as a resistance value, and the first preset condition is set as a size judgment condition of the resistance value and the resistance threshold. If the resistance value is less than the resistance threshold, it is determined that the first preset condition is met. If the resistance is not less than the resistance threshold, it is determined that the first preset condition is not met. Using the resistance value judgment can accurately realize the judgment of the state of oxide layer removal.

[0111] Step S203, when the residual thickness is greater than a first thickness threshold, using a laser to clean the abnormally oxidized area until the residual thickness is no greater than the first thickness threshold, and then pressurizing the first voltage value to obtain the pressurized first voltage value.

[0112] The residual thickness is compared with a first thickness threshold, for example, the first thickness threshold is 20 nm. If the residual thickness is greater than the first thickness threshold, the effect of removing the oxide layer by using voltage is poor when the thickness is high. Therefore, a laser can be used to clean the area to remove the oxide layer, which can improve efficiency.

[0113] The thickness of the oxide layer is monitored in real time, so that voltage can be used to remove the oxide layer after the residual thickness is no more than the first thickness threshold. Of course, at this time, since the voltage used previously cannot meet the removal effect, the voltage needs to be increased to increase the voltage value when removing the oxide layer.

[0114] A fixed step value can be used to pressurize the first voltage value. For example, the step value is 0.5V. When the current first voltage value is 3V, the first voltage value after pressurization is 3.5V when the voltage is used for removal next time. If it is still not completely clear next time, the first voltage value is pressurized again in step S203 to obtain a pressurized first voltage value of 4V.

[0115] Optionally, the step of applying a first voltage value to the abnormally oxidized region until the oxide layer in the abnormally oxidized region is broken down further comprises:

[0116] Recording a breakdown voltage of the oxide layer in the abnormally oxidized region;

[0117] After the first voltage value is pressurized to obtain the pressurized first voltage value, the method further includes:

[0118] detecting whether the first voltage value after the pressurization exceeds the breakdown voltage;

[0119] If the first voltage value after pressurization exceeds the breakdown voltage, the first voltage value after pressurization is restored to the voltage value before pressurization.

[0120] Among them, after breaking through the oxide layer in the abnormal oxidation area, it is also necessary to record the breakdown voltage of the oxide layer in the abnormal oxidation area, so as to avoid exceeding the breakdown voltage during the subsequent pressurization process, thereby avoiding breakdown damage to the superconducting device.

[0121] In step S204 , the first voltage value after pressurization is used as the first voltage value, and the process of applying the first voltage value to the abnormally oxidized region is returned to execution until the residual thickness is less than a second thickness threshold, and then detecting a second resistance state of the abnormally oxidized region after breakdown.

[0122] The first voltage value formed after the pressurization is used as the first voltage value, and the voltage removal process is repeated until the residual thickness is detected to be less than a second thickness threshold. The second thickness threshold is less than the first thickness threshold, for example, the second thickness threshold is 0.5 nm. If the residual thickness is less than the second thickness threshold, it is necessary to detect the second resistance state of the abnormally oxidized region at this time for comparison with the first resistance state to determine whether the removal effect is satisfactory.

[0123] The second resistance state after the abnormal oxidation region is broken down is detected by adjusting the voltage of the voltage probe device to a low voltage (eg, 0.1 V) to perform resistance detection on the device.

[0124] Optionally, before detecting the second resistance state of the abnormally oxidized region after breakdown, the method further includes:

[0125] detecting the surface roughness of the abnormally oxidized area;

[0126] If the surface roughness is less than the roughness threshold, detecting the second resistance state of the abnormally oxidized region after breakdown is performed;

[0127] If the surface roughness is not less than the roughness threshold, the method returns to executing the step of applying the first voltage value to the abnormal oxidation region.

[0128] In addition to measuring the thickness, the surface roughness of the abnormally oxidized area also needs to be measured to improve the uniformity of the oxide layer removal and the removal effect. In one embodiment, the roughness threshold can be 2 nm.

[0129] Step S205 , determining a qualification determination parameter according to the first resistance state and the second resistance state, and determining that the oxide layer removal is completed when the qualification determination parameter meets a second preset condition.

[0130] Among them, the qualified judgment parameter can be calculated from the first resistance state and the second resistance state, and is used to express the resistance state changes of the first resistance state and the second resistance state. When the two resistance state changes meet the second preset condition, it is determined that the oxide layer removal is completed.

[0131] Optionally, the first resistance state is a first resistance value, the second resistance state is a second resistance value, and determining the qualification determination parameter according to the first resistance state and the second resistance state includes:

[0132] Calculating a difference between the first resistance value and the second resistance value to obtain a resistance difference value, and comparing the resistance difference value with the first resistance value to obtain a ratio as a qualification determination parameter;

[0133] detecting whether the qualification determination parameter is less than a ratio threshold, and if the qualification determination parameter is less than the ratio threshold, determining that the qualification determination parameter satisfies a second preset condition;

[0134] If the qualification determination parameter is not less than the ratio threshold, it is determined that the qualification determination parameter does not meet the second preset condition.

[0135] In this embodiment, the second preset condition may be ΔR / R1<5%, which is considered qualified, wherein R1 is the first resistance value, ΔR=|R2-R1|, R2 is the second resistance value, and the ratio threshold is 5%.

[0136] For example, the voltage breakdown-laser cleaning synergy mechanism is used: low-voltage pre-detection → high-voltage breakdown positioning → laser precise cleaning steps:

[0137] Step S1: Use a four-probe low-voltage scan (0.1 V) to draw an initial resistance distribution map and mark abnormally high resistance points (R>1000Ω);

[0138] Step S2: Use a step-by-step voltage boost method (5V→8V→12V→15V…20V or 3V→3.5V→4V→…20V, for 50ms) to apply high voltage to the abnormally high-resistance area marked on the device surface to break down the oxide layer there. Record the breakdown voltage Vbd, then adjust the applied voltage to a constant voltage of 0.1V. In-situ test the post-breakdown resistance R1. Note that step S2 imposes a current limit of ≤10 mA on the semiconductor parameter analyzer to prevent overcurrent damage to the device.

[0139] If R1<10Ω, it means that the surface oxide film has been completely removed, and then jump to step S5;

[0140] If R1>10Ω, it indicates that the surface oxide layer has not been completely removed, and then proceed to step S3 for further analysis using an ellipsometer;

[0141] Step S3: The ellipsometer scans the breakdown area. If the residual oxide layer thickness is detected to be greater than 20nm, laser cleaning is initiated (energy density 1.2J / cm²). If the residual oxide layer thickness is detected to be less than 20nm, the process returns to step S2 and the voltage is continued to be increased.

[0142] Step S4: The ellipsometer provides real-time feedback on the cleaning progress until the oxide layer thickness is less than 0.5 nm and the surface roughness Ra is less than 2 nm;

[0143] Step S5: Apply a 0.1V constant voltage with four probes to re-measure the resistance R2. If ΔR / R1 is less than 5%, the test is qualified. Otherwise, return to S3.

[0144] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the scope of protection of the present invention.

Claims

1. A method for removing the oxide layer on the surface of a superconducting device, characterized in that: include: Scanning the surface of the superconducting device to be processed to determine an abnormal oxidation region, and applying a first voltage value to the abnormal oxidation region until the oxide layer in the abnormal oxidation region is broken down; adjusting the first voltage value to a second voltage value to detect the abnormally oxidized region, obtaining a first resistance state of the abnormally oxidized region after breakdown, and if the first resistance state does not meet a first preset condition, collecting a residual thickness of an oxide layer remaining in the abnormally oxidized region in real time, and the second voltage value is less than the first voltage value; When the residual thickness is greater than a first thickness threshold, the abnormally oxidized region is cleaned using a laser until the residual thickness is no greater than the first thickness threshold, and the first voltage value is pressurized to obtain the pressurized first voltage value; Using the first voltage value after pressurization as the first voltage value, returning to the step of applying the first voltage value to the abnormally oxidized region until the residual thickness is less than a second thickness threshold, and detecting a second resistance state of the abnormally oxidized region after breakdown; A qualification determination parameter is determined according to the first resistance state and the second resistance state, and when the qualification determination parameter meets a second preset condition, it is determined that the oxide layer removal is completed.

2. The method for removing the surface oxide layer of a superconducting device according to claim 1, characterized in that: Before collecting the residual thickness of the oxide layer remaining in the abnormal oxidation region in real time if the first resistance state does not satisfy the first preset condition, the method further includes: detecting whether the first resistance state satisfies a first preset condition; If the first resistance state satisfies the first preset condition, detecting a second resistance state after the abnormal oxidation region is broken down is performed.

3. The method for removing the surface oxide layer of a superconducting device according to claim 2, characterized in that: If the first resistance state is a resistance value, detecting whether the first resistance state satisfies a first preset condition includes: detecting whether a resistance value corresponding to the first resistance state is less than a resistance threshold, and determining that the first resistance state satisfies the first preset condition if the resistance value corresponding to the first resistance state is less than the resistance threshold; If the resistance value corresponding to the first resistance state is not less than the resistance threshold, it is determined that the first resistance state does not meet the first preset condition.

4. The method for removing the surface oxide layer of a superconducting device according to claim 1, wherein: Also includes: Obtaining the overcurrent of the superconducting device to be processed; The applying a first voltage value to the abnormal oxidation region includes: A first voltage value is applied to the abnormal oxidation region, and a current during the application is controlled to be smaller than the overcurrent.

5. The method for removing the surface oxide layer of a superconducting device according to claim 1, characterized in that: Before detecting the second resistance state of the abnormally oxidized region after breakdown, the method further includes: detecting the surface roughness of the abnormally oxidized area; If the surface roughness is less than the roughness threshold, detecting the second resistance state of the abnormally oxidized region after breakdown is performed; If the surface roughness is not less than the roughness threshold, the method returns to executing the step of applying the first voltage value to the abnormal oxidation region.

6. The method for removing the surface oxide layer of a superconducting device according to claim 1, characterized in that: The first resistance state is a first resistance value, the second resistance state is a second resistance value, and determining the qualification determination parameter according to the first resistance state and the second resistance state includes: Calculating a difference between the first resistance value and the second resistance value to obtain a resistance difference value, and comparing the resistance difference value with the first resistance value to obtain a ratio as a qualification determination parameter; detecting whether the qualification determination parameter is less than a ratio threshold, and if the qualification determination parameter is less than the ratio threshold, determining that the qualification determination parameter satisfies a second preset condition; If the qualification determination parameter is not less than the ratio threshold, it is determined that the qualification determination parameter does not meet the second preset condition.

7. The method for removing the surface oxide layer of a superconducting device according to claim 1, characterized in that: After applying a first voltage value to the abnormally oxidized region until the oxide layer in the abnormally oxidized region is broken down, the method further includes: Recording a breakdown voltage of the oxide layer in the abnormally oxidized region; After the first voltage value is pressurized to obtain the pressurized first voltage value, the method further includes: detecting whether the first voltage value after the pressurization exceeds the breakdown voltage; If the first voltage value after pressurization exceeds the breakdown voltage, the first voltage value after pressurization is restored to the voltage value before pressurization.

8. The method for removing the surface oxide layer of a superconducting device according to claim 1, characterized in that: Before scanning the surface of the superconducting device to be processed to determine the abnormal oxidation area, the method further includes: Obtaining the device type of the superconducting device to be processed, and detecting the initial thickness of the oxide layer on the surface of the superconducting device to be processed; Determining whether to use a voltage removal technique or a laser removal technique to remove the oxide layer according to the device type and the initial thickness; If it is determined to use the voltage removal technology, performing the surface scanning on the superconducting device to be processed to determine the abnormal oxidation area; If it is determined to use the laser removal technology, before performing the surface scanning of the superconducting device to be processed and determining the abnormal oxidation area, the laser parameters are adjusted according to the initial thickness and the oxide layer of the superconducting device to be processed is removed using the laser parameters.

9. The method for removing the surface oxide layer of a superconducting device according to claim 8, characterized in that: After removing the oxide layer of the superconducting device to be processed by using the laser parameters, the method further includes: The surface of the superconducting device to be processed is scanned to determine abnormal oxidation areas.

10. A system for removing oxide layer from the surface of a superconducting device, characterized in that: The system for removing the surface oxide layer of a superconducting device comprises: a voltage probe device, a laser device, an ellipsometer monitoring device and a control device, wherein the control device is connected to the voltage probe device, the laser device and the ellipsometer monitoring device; Scanning the surface of the superconducting device to be processed using the voltage probe device to determine an abnormal oxidation region, and applying a first voltage value to the abnormal oxidation region until the oxide layer in the abnormal oxidation region is broken down; Using the voltage probe device to adjust the first voltage value to a second voltage value to detect the abnormally oxidized region, obtaining a first resistance state of the abnormally oxidized region after breakdown, and if the first resistance state does not meet a first preset condition, using the ellipsometer monitoring device to collect a residual thickness of the residual oxide layer in the abnormally oxidized region in real time, and the second voltage value is less than the first voltage value; The laser device is used to clean the abnormally oxidized area using a laser when the residual thickness is greater than a first thickness threshold, and after the residual thickness is no greater than the first thickness threshold, pressurize the first voltage value in the voltage probe device to obtain the pressurized first voltage value; The voltage probe device is configured to use the first voltage value after pressurization as the first voltage value, return to applying the first voltage value at the abnormally oxidized region until the residual thickness is less than a second thickness threshold, and detect a second resistance state of the abnormally oxidized region after breakdown; The control device is used to determine a qualification judgment parameter according to the first resistance state and the second resistance state, and determine that the oxide layer removal is completed when the qualification judgment parameter meets a second preset condition.

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