Insulation coating defect detection method and detection system

Abstract

The present application relates to the field of semiconductor equipment technology, and provides an insulating coating defect detection method and detection system, the method comprising: contacting the conductive surface of the substrate to be detected that is opposite to the coating surface with the lower electrode to form a flat electrode; arranging the coating surface of the substrate to be detected relative to the upper electrode according to a preset spacing; applying a preset voltage to the upper electrode so that the upper electrode can form a tip discharge; starting a motion control module, clamping the upper electrode to move according to a preset detection path, and being able to cover the coating surface of the substrate to be detected, wherein the detection path is generated according to the shape of the substrate to be detected and the characteristics of the coating surface; checking whether there is a position on the coating surface where a tip discharge is generated, and the position where a tip discharge is generated indicates that the porosity of this position exceeds the set standard, and the position where a tip discharge is not generated indicates that the porosity of this position meets the set standard. The present application performs defect detection through tip discharge without damaging the coating, thereby improving the defect detection efficiency.

Description

Technical Field

[0001] The present application relates to the field of semiconductor equipment technology, and in particular to an insulating coating defect detection method and detection system. Background Art

[0002] When semiconductor process equipment is in operation, plasma discharge inside the cavity will cause corrosion to the components inside the cavity. Therefore, the surface of the components inside the cavity needs to be modified to improve its corrosion resistance.

[0003] Plasma spraying technology can form a dense anti-corrosion coating on the surface of the material. However, due to the characteristics of the material and processing technology, the coating prepared by plasma spraying technology inevitably has porosity defects; porosity defects will affect the corrosion resistance of the coating. Therefore, it is necessary to monitor the porosity of the coating to improve the processing technology of the coating.

[0004] The existing defect detection method uses metallographic testing to directly measure. Since metallographic testing is destructive, only a control group can be set up, and the data of the control group can reflect the porosity of the coating. However, the control group data only represents the porosity of some samples, and cannot cover all products or all parts of the products. This cannot accurately reflect the quality of the overall coating of the product. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present application provides an insulating coating defect detection method and detection system, which aims to perform comprehensive defect detection on the coating of the substrate to be inspected through tip discharge without damaging the coating. The defects of the product coating can be detected quickly and conveniently, thereby improving the defect detection efficiency.

[0006] In order to achieve the above objectives and other advantages, the present application adopts the following technical solutions:

[0007] In a first aspect, the present application provides an insulating coating defect detection method, which is applied to a test device for detecting the breakdown characteristics of an insulating medium, wherein the test device comprises a vacuum chamber, wherein a test platform and a motion control module are arranged in the vacuum chamber, wherein the test platform comprises an upper electrode and a lower electrode arranged opposite to each other, wherein the upper electrode is a tip electrode, and wherein the motion control module comprises a clamping portion capable of clamping the upper electrode for movement, wherein the method comprises:

[0008] The conductive surface of the substrate to be tested, which is opposite to the plated surface, is brought into contact with the lower electrode to form a flat electrode;

[0009] The plated surface of the substrate to be detected is arranged opposite to the upper electrode at a preset distance;

[0010] Applying a preset voltage to the upper electrode so that the upper electrode can form a tip discharge;

[0011] Starting the motion control module to clamp the upper electrode and move it along a preset detection path, so as to cover the coating layer of the substrate to be detected, wherein the detection path is generated according to the shape of the substrate to be detected and the characteristics of the coating layer;

[0012] Check whether there are locations where tip discharge occurs on the coating surface. Locations where tip discharge occurs indicate that the porosity at these locations exceeds the set standard, and locations where tip discharge does not occur indicate that the porosity at these locations meets the set standard.

[0013] According to an insulating coating defect detection method provided by the present application, the steps of starting the motion control module, clamping the upper electrode to move along a preset detection path, and being able to cover the coating surface of the substrate to be detected include:

[0014] Loading a preset detection path into the motion control module in a specific format, the detection path including: coordinate points, speed and acceleration;

[0015] The detection start instruction is inputted through a host computer connected to the test device, and the motion control module controls the clamping part clamping the upper electrode to move according to the detection path in response to the detection start instruction;

[0016] When the upper electrode completes the detection according to the detection path, the motion control module controls the upper electrode to return to the starting point of the path, and outputs a detection completion instruction to feed back to the host computer.

[0017] According to an insulating coating defect detection method provided in the present application, the motion control module includes a photoelectric encoder. During the movement process, the photoelectric encoder can monitor the position and speed parameters of the upper electrode in real time, and adjust them according to actual needs to ensure that the upper electrode moves accurately along the detection path.

[0018] According to an insulating coating defect detection method provided in the present application, the motion control module includes: a first transmission mechanism and a second transmission mechanism, the first transmission mechanism has a lateral motion control function, and the second transmission mechanism has a longitudinal motion control function, so as to achieve precise positioning of the upper electrode in two-dimensional or three-dimensional space.

[0019] According to a method for detecting defects in insulating coatings provided by the present application, the step of generating the detection path according to the shape of the substrate to be detected and the characteristics of the coating surface includes:

[0020] Acquire the three-dimensional shape data of the substrate to be inspected and the profile and size of the coating surface;

[0021] Based on the three-dimensional shape data and the contour and size of the coating surface, one or more detection paths that can cover the entire coating surface are generated through a path simulation generation algorithm.

[0022] According to an insulating coating defect detection method provided in the present application, the setting standard of the porosity is between 2% and 5%.

[0023] According to a method for detecting defects in insulating coatings provided by the present application, the method further includes:

[0024] The test device is evacuated or nitrogen is injected during evacuation to form a low-pressure environment.

[0025] According to a method for detecting defects in insulating coatings provided by the present application, the method further includes:

[0026] The upper electrode is set as a negative electrode, and the lower electrode is set as a positive electrode, so that a strong ionization area is formed near the upper electrode, which is conducive to the formation of a streamer and further reduces the corona starting voltage.

[0027] In a second aspect, the present application provides an insulation coating defect detection system, comprising:

[0028] A test device for detecting the breakdown characteristics of an insulating medium, the test device comprising a vacuum chamber in which a test platform and a motion control module are arranged;

[0029] The test platform comprises an upper electrode and a lower electrode arranged opposite to each other, wherein the upper electrode is a pointed electrode;

[0030] The substrate to be detected includes a plated surface and a conductive surface that are arranged opposite to each other, the lower electrode contacts the conductive surface to form a flat electrode, and the plated surface is arranged opposite to the upper electrode at a preset interval;

[0031] The motion control module has a clamping portion, which can clamp the upper electrode to move along a preset detection path, and the detection path is generated according to the shape of the substrate to be detected and the characteristics of the coating layer to cover the coating layer of the substrate to be detected;

[0032] A host computer is connected to the test device, and is used to control the operation of the test device and to transmit data and send control instructions.

[0033] According to an insulating coating defect detection system provided by the present application, the host computer is specifically used for:

[0034] Setting the applied voltage of the electrodes, the preset spacing and the parameters of the detection path;

[0035] receiving and displaying the detection data transmitted by the testing device, wherein the detection data includes the position information of the tip discharge generated on the coating surface;

[0036] A defect detection report is generated according to the detection data to evaluate the coating quality of the substrate to be detected.

[0037] The present application provides an insulating coating defect detection method and detection system, which forms a flat electrode by contacting the conductive surface of the substrate to be detected that is opposite to the coating surface with the lower electrode; the coating surface of the substrate to be detected is arranged relative to the upper electrode according to a preset spacing; a preset voltage is applied to the upper electrode so that the upper electrode can form a tip discharge; the motion control module is started, and the upper electrode is clamped to move according to a preset detection path, which can cover the coating surface of the substrate to be detected, wherein the detection path is generated according to the shape of the substrate to be detected and the characteristics of the coating surface; the coating surface is checked to see if there is a position where a tip discharge is generated, and the position where a tip discharge is generated indicates that the porosity of this position exceeds the set standard, and the position where a tip discharge is not generated indicates that the porosity of this position meets the set standard. The present application performs defect detection on the coating that exceeds the porosity standard by tip discharge without destroying the coating, and performs a full range of defect detection on the coating according to the preset detection path, so that the defects of the product coating can be detected quickly and conveniently, and the defect detection efficiency is improved. Moreover, it can be used in large-scale production, greatly reducing the time and cost of coating inspection. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other implementation methods can be obtained based on these drawings without paying any creative work.

[0039] Figure 1 It is a schematic diagram of the flow of the insulation coating defect detection method provided in an embodiment of the present application;

[0040] Figure 2 It is a characteristic diagram of the Baschen curve corresponding to different gases provided in the embodiment of the present application. DETAILED DESCRIPTION

[0041] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the following specifically cites the preferred embodiments and describes them in detail with the accompanying drawings.

[0042] It should be noted that it is explicitly and implicitly understood by those of ordinary skill in the art that the embodiments described in this application can be combined with other embodiments without conflict. Unless otherwise defined, the technical terms or scientific terms involved in this application should be the usual meanings understood by people with ordinary skills in the technical field to which this application belongs. The words "one", "a", "a", "the" and the like involved in this application do not indicate a quantitative limitation and may represent the singular or plural. The terms "including", "comprising", "having" and any of their variations involved in this application are intended to cover non-exclusive inclusions; the terms "first", "second", "third", etc. involved in this application are merely to distinguish similar objects and do not represent a specific ordering of objects.

[0043] When semiconductor process equipment is in operation, the plasma discharge inside the cavity will corrode the parts inside the cavity. When enterprises produce related equipment and parts, plasma spraying technology can form a dense anti-corrosion coating on the surface of the material. In the coating process, the sample standard sheet other than the target product is coated with the same coating conditions (the sample standard sheet is a sample substrate of the same material as the product, which can be rectangular, circular, etc.), and the sample standard sheet is directly measured for porosity (porosity = (pore area / total selected area) × 100%) by metallographic detection (using the camera system of the metallographic microscope or a digital camera to obtain the image of the coating, and analyze the microstructure of the coating material, including parameters such as porosity) to reflect the porosity of the coating of the target product, and then evaluate the quality of the coating. But in fact, the surface to be coated of the product is actually much more complex than the standard rectangular surface. For example, the product is a long strip, tubular or curved structural part. Since there are many hard-to-reach corners and gaps in complex structural parts, the existing technology may not be able to effectively detect the coating quality of these areas, making the detection data incomplete. Therefore, an insulating coating defect detection method and detection system provided in an embodiment of the present application performs all-round defect detection on the coating of the substrate to be inspected through tip discharge without damaging the coating, so as to improve defect detection efficiency.

[0044] Reference Figure 1 As shown, an embodiment of the present application provides an insulating coating defect detection method, which is applied to a test device for detecting the breakdown characteristics of an insulating medium. The test device includes a vacuum chamber, in which a test platform and a motion control module are arranged. The test platform includes an upper electrode and a lower electrode arranged relatively to each other, the upper electrode is a pointed electrode, and the motion control module has a clamping portion that can clamp the upper electrode for movement.

[0045] The upper electrode is connected to the high-voltage power supply lead, and the shape of the upper electrode is set to be a pointed shape, so that the charge is more easily concentrated at the tip, thereby enhancing the tip discharge effect. The lower electrode is connected to the grounding electrode lead, and the entire test device is grounded to prevent leakage of the high-voltage device. The upper electrode and the lower electrode are respectively fixed on a fixed plate, and the fixed plate is an insulating material. The clamping part can be a robotic arm or a clamp, etc.

[0046] The air pressure in the vacuum chamber needs to be set to a low vacuum condition to reduce the insulation capacity of the air gap and eliminate the influence of the conductivity of the coating material on the detection. The low vacuum condition that satisfies the Thomson discharge is set to 0.1~10 (cm×torr) and the measurement is performed. Any general vacuum pump can meet this environmental condition.

[0047] The test method includes:

[0048] Step S1: The conductive surface of the substrate to be inspected, which is opposite to the plated surface, is brought into contact with the lower electrode to form a flat electrode.

[0049] The conductive surface of the substrate to be tested is opposite to the coating surface, and the conductive surface is brought into contact with the lower electrode to form a flat electrode. The flat electrode can provide a stable and reliable electrical contact surface to ensure that the current can pass smoothly through the coating and realize tip discharge detection when necessary. The lower electrode can be brought into close contact with the conductive surface of the sample substrate through an appropriate clamping device or fixing device to ensure that the connection between the lower electrode and the conductive surface is stable and reliable during the detection process.

[0050] For substrates to be tested in three-dimensional shapes, such as blocks, columns, or curved surfaces, a lower electrode with a larger contact area or a special shape can be set according to actual conditions to ensure full contact with the conductive surface of the sample. At the same time, a suitable fixing method is selected according to the size and shape of the electrode, such as adhesive bonding, mechanical fixing, etc., to ensure a stable and reliable connection between the lower electrode and the conductive surface.

[0051] Step S2: placing the plated surface of the substrate to be inspected opposite to the upper electrode at a preset distance.

[0052] The upper electrode is placed on the upper surface of the coating at a preset interval, so that the upper electrode always moves above the coating at a preset interval. The preset interval needs to be accurately set according to factors such as the thickness of the coating, the material of the coating, and the detection requirements.

[0053] Step S3: applying a preset voltage to the upper electrode so that the upper electrode can form a tip discharge.

[0054] The voltage applied between the upper electrode and the lower electrode must be high enough to break through the air and produce tip discharge when there are large gaps in the coating (such as bubble defects and impurity defects). When the shape of the tip electrode, the air pressure conditions, and the voltage conditions are set the same, whether tip discharge occurs is related to the size of the pores in the coating. When the pores are small (meeting the porosity requirements), the breakdown ability is insufficient to generate current pulses. When the pores are large, such as when obvious bubble defects and impurity defects appear, the insulation ability of the pores is weaker than that of the coating material, and it can break through and produce tip discharge.

[0055] Step S4: Start the motion control module to clamp the upper electrode and move it along a preset detection path to cover the coating layer of the substrate to be detected, wherein the detection path is generated according to the shape of the substrate to be detected and the characteristics of the coating layer.

[0056] In this embodiment, the steps of generating the detection path according to the shape of the substrate to be detected and the characteristics of the coating layer specifically include:

[0057] Obtaining the three-dimensional shape data of the substrate to be inspected and the profile and size of the coating surface;

[0058] Based on the three-dimensional shape data and the contour and size of the coating surface, one or more detection paths that can cover the entire coating surface are generated through a path simulation generation algorithm.

[0059] Specifically, the three-dimensional shape data of the sample substrate is obtained by measuring or according to the three-dimensional modeling data of the substrate to be tested, and the profile and size of the coating surface are understood. According to the three-dimensional shape data, the profile and size of the coating surface, computer algorithms or software, such as the Motion plug-in of SolidWorks software, are used to simulate the motion process of the object, and static and dynamic interference checks are performed, so as to assist in generating a reasonable motion path. The motion path used in the spraying process can also be used for path planning.

[0060] In practical applications, it may be necessary to comprehensively consider factors such as the shape of the substrate to be inspected, the characteristics of the coating surface, the detection accuracy requirements, and computing resources, and select appropriate algorithms or software for path generation. For example, for substrates to be inspected with complex shapes and high accuracy requirements, it may be necessary to use a diversified path simulation generation algorithm based on physical properties or combine other algorithms for path optimization.

[0061] In this embodiment, step S4 specifically includes:

[0062] Step S401: loading a preset detection path into a motion control module in a specific format, the detection path including: coordinate points, speed and acceleration;

[0063] Step S402: inputting a detection start instruction through a host computer connected to the test device, and the motion control module controls the clamping part clamping the upper electrode to move according to the detection path in response to the detection start instruction;

[0064] Step S403: When the upper electrode completes the detection according to the detection path, the motion control module controls the upper electrode to return to the starting point of the path, and outputs a detection completion instruction to feed back to the host computer.

[0065] Specifically, the host computer is connected to the test device by wired or wireless means, and the control system in the host computer is initialized, such as selecting a suitable communication interface to achieve data transmission and the sending of control instructions. The detection path is loaded into the motion control module, which involves inputting the relevant parameters in the detection path, such as coordinate points, speed, acceleration, etc., into the motion control module in a specific communication format. The setting of parameters needs to take into account the detection accuracy, efficiency, and physical limitations of the mechanical device, such as the maximum speed and acceleration capability of the motor.

[0066] Enter the detection start command in the application interface of the control system, and the host computer sends the command to the motion control module, which interprets the command and converts it into the actual movement of the mechanical device. The mechanical arm holding the upper electrode is controlled to start moving according to the loaded detection path.

[0067] The motion control module monitors the position and status of the upper electrode in real time. When it detects that the upper electrode has completed all detection points along the preset path, it triggers the return command. Under the control of the motion control module, the upper electrode safely returns to the starting point along the preset path or the shortest path to prepare for the next detection or enter the standby state. After completing the detection and returning to the starting point, the motion control module sends a detection completion command to the host computer through the communication interface, including detection status, timestamp and other information. Automatically returning to the starting point and feeding back the detection completion command realizes closed-loop control of the detection process and improves the degree of automation.

[0068] The above process is carried out in an automated manner, reducing human intervention and improving detection efficiency and accuracy.

[0069] In this embodiment, the motion control module includes a photoelectric encoder. During the motion process, the photoelectric encoder can monitor the position and speed parameters of the upper electrode in real time, and make adjustments according to actual needs to ensure that the upper electrode moves accurately along the detection path.

[0070] Specifically, the photoelectric encoder is usually installed on the motor shaft that drives the upper electrode to move or on the mechanical transmission component connected thereto. When the upper electrode starts to move, the photoelectric encoder starts to generate signals, which are received and analyzed by the motion control module to achieve the purpose of monitoring the real-time position and speed. If it is found that the position or speed of the upper electrode deviates from the preset detection path or parameter range, the motion control module immediately makes dynamic adjustments. It is also possible that when the real-time position or speed deviates from the preset detection path or parameter range, the motion control module automatically pauses the movement and re-adjusts the actual operating parameters, such as changing the driving current of the motor, adjusting the acceleration or deceleration, etc., to ensure that the upper electrode can quickly return to the correct detection path. The entire monitoring and adjustment process is a closed-loop feedback control system, which continuously monitors and adjusts the motion state of the upper electrode to achieve precise control.

[0071] Step S5: Check whether there are locations on the coating surface where tip discharge occurs. Locations where tip discharge occurs indicate that the porosity at these locations exceeds a set standard, and locations where tip discharge does not occur indicate that the porosity at these locations meets the set standard.

[0072] Use sensors or detection devices to record the specific locations where tip discharges occur on the coating surface. These locations correspond to areas where the porosity exceeds the set standard. The recorded discharge location, discharge intensity and other information are formed into test data and transmitted to the host computer control system. The control system forms a test report through analysis and collation. The test report can be a graphical representation of the discharge distribution map on the coating surface, accompanied by a detailed text description. This facilitates further analysis, processing and decision-making. This helps to achieve accurate monitoring and management of coating quality, and improve product quality and production efficiency.

[0073] In this embodiment, the motion control module includes: a first transmission mechanism and a second transmission mechanism, the first transmission mechanism has a lateral motion control function, and the second transmission mechanism has a longitudinal motion control function, so as to achieve precise positioning of the upper electrode in two-dimensional or three-dimensional space.

[0074] Specifically, the motion control module includes a controller, a sensor, a driver, etc. The transmission mechanism includes different types of transmission components such as motors, lead screws, guide rails, gears, bearings, etc. The driver drives the motor to rotate, and the controller converts the rotational motion of the motor into linear motion or rotational motion of the upper electrode in two-dimensional or three-dimensional space. Specifically, lateral motion control: by controlling the movement of the motor in the horizontal direction, combined with the conversion effect of the mechanical device, the motion control of the upper electrode in the X-axis and Y-axis directions can be achieved; longitudinal motion control: by controlling the movement of the motor in the vertical direction, combined with the conversion effect of the mechanical device, the motion control of the upper electrode in the Z-axis direction can be achieved.

[0075] In this embodiment, the setting standard of porosity is between 2% and 5%. The spraying method includes: plasma spraying, nano spraying, cold spraying, etc. In this embodiment, the plasma spraying method is preferably used for spraying. The qualified standard of porosity of the coating formed by plasma spraying is between 2% and 5%.

[0076] During the plasma spraying process, the insulating material is heated to a molten or semi-molten state and sprayed at high speed onto the pre-treated workpiece surface to form a firmly adhered insulating surface layer. This coating not only has excellent corrosion resistance, but also improves the material's comprehensive properties such as wear resistance, high temperature oxidation resistance and electrical insulation.

[0077] The coating thickness can be controlled by adjusting the process parameters (such as spraying time, spraying rate, etc.) during the plasma spraying process to ensure that the coating thickness ranges from thinner (such as 200μm) to thicker (such as 1000μm) multiple thickness levels.

[0078] In this embodiment, the detection method further includes:

[0079] The test device is evacuated or nitrogen is injected during evacuation to form a low-pressure environment.

[0080] The test device also includes an air pressure control module for adjusting the air pressure in the vacuum chamber to a preset range to optimize the detection conditions of the tip discharge. The air pressure control module includes a vacuum pump and a vacuum gauge, through which a low-pressure vacuum environment is obtained and its vacuum degree is monitored.

[0081] It should be noted that the coating material itself is insulating. Under normal room temperature and pressure, the insulation strength of air is 3-5kV / mm, and the insulation strength of the ceramic coating is 13-20kV / mm. Although there is a multiple difference in the insulation capacity between the two, there is no difference in order of magnitude. Therefore, setting the air pressure in the vacuum chamber to a low-pressure low-vacuum environment can effectively reduce the insulation capacity of the air gap, and the pores have stronger conductivity, which can eliminate the influence of the conductivity of the ceramic coating material on the test results. In other words, the coating is regarded as absolutely insulating, and the discharge under low-pressure conditions can be considered to be caused only by the pore discharge of the coating, which makes the tip discharge more accurately reflect the discharge characteristics of the pores.

[0082] When the test device is evacuated, various gases can be injected to measure its ionization characteristics under specific gas environment conditions. These gases mainly include: air (Air), nitrogen (N2), neon (Ne), helium (He), argon (Ar) and hydrogen (H2). The Baschen curve of each gas is as follows Figure 2 As shown, the Baschen curve describes the breakdown voltage V of a gas gap in a uniform electric field. tThe relationship between pressure and distance (cm·Torr). The Baschen curve is usually U-shaped with a minimum point. On the left side of the curve, when the pressure is low or the electrode spacing is large, the breakdown voltage V t Higher; on the right side of the curve, when the gas pressure is higher or the electrode spacing is smaller, the breakdown voltage V t is also higher; at the minimum point of the curve, the breakdown voltage V t The minimum breakdown voltage V corresponding to different gases is s.min and the corresponding (pd) min The values ​​(the minimum value of the product of the gas gap d and the gas pressure p, in cm·Torr) are shown in Table 1.

[0083] Table 1 Dielectric properties data corresponding to different gases

[0084]

[0085] The air pressure control module can also control the inflation valve and exhaust valve on the vacuum chamber. Specific gases at the level of several Pa or more than ten Pa are filled in through the inflation valve and then pumped to a low pressure state. After repeated inflation and exhaust of the gas, the air in the pipeline is removed to prevent water vapor and other gas molecules from freezing in the pipeline or vacuum chamber during low-temperature testing.

[0086] Preferably, in this embodiment, nitrogen (N2) is injected during vacuuming. Nitrogen has a relatively high ionization energy and a low degree of ionization at a lower voltage, and may show a lower initial conductivity in the measurement, but changes significantly with increasing voltage.

[0087] In this embodiment, the detection method further includes:

[0088] The upper electrode is set as a negative electrode and the lower electrode is set as a positive electrode, so that a strong ionization area is formed near the upper electrode, which is conducive to the formation of a streamer and thus reduces the corona starting voltage.

[0089] When the upper electrode (tip electrode) is negative and the lower electrode is positive, according to the principle of electric field distribution, the electric field lines will point from the positive electrode to the negative electrode. Due to the sharp shape of the tip electrode, the electric field lines will be denser near the tip, resulting in an increase in the electric field strength in this area, forming a strong ionization region near the upper electrode. In the area with enhanced ionization, electrons and ions begin to accumulate rapidly to form a charged region. As the charged region expands, a conductive channel gradually forms, i.e., a streamer. The formation of a streamer marks the beginning of discharge, and if the conditions are met at this time, a tip discharge will occur. Due to the increase in ionization and the formation of a streamer, the threshold of the corona initiation voltage is lowered. The corona initiation voltage refers to the minimum voltage at which the gas medium is ionized and luminescence begins to occur when the electric field strength increases to a certain level.

[0090] Those skilled in the art will appreciate that, in the above method of specific implementation, the order in which the steps are written does not imply a strict execution order and does not constitute any limitation on the implementation process. The specific execution order of the steps should be determined by their functions and possible internal logic.

[0091] The present application also provides an insulation coating defect detection system, including:

[0092] A test device for detecting the breakdown characteristics of an insulating medium, the test device comprising a vacuum chamber, wherein a test platform and a motion control module are arranged in the vacuum chamber;

[0093] The test platform includes an upper electrode and a lower electrode which are arranged opposite to each other, and the upper electrode is a tip electrode;

[0094] The substrate to be tested includes a plated surface and a conductive surface that are arranged opposite to each other, the lower electrode contacts the conductive surface to form a flat electrode, and the plated surface is arranged opposite to the upper electrode at a preset interval;

[0095] The motion control module has a clamping part, which can clamp the upper electrode and move it along a preset detection path. The detection path is generated according to the shape of the substrate to be detected and the characteristics of the coating layer to cover the coating layer of the substrate to be detected.

[0096] The host computer is connected to the test device and is used to control the operation of the test device and to transmit data and send control instructions.

[0097] According to an insulation coating defect detection system provided by the present application, the host computer is specifically used for:

[0098] Setting the parameters of the applied voltage, preset spacing and detection path of the electrodes;

[0099] Receive and display the detection data transmitted by the test device, the detection data including the location information of the tip discharge generated on the coating surface;

[0100] Generate defect detection reports based on the inspection data to evaluate the coating quality of the inspected substrate.

[0101] Specifically, start the host computer and set the electrode applied voltage, preset spacing (i.e., the distance between the upper electrode and the coating layer) and detection path parameters through the host computer's operation interface. These parameters should be set according to the characteristics of the coating and the expected detection accuracy. Place the substrate to be tested on the test platform, ensuring that the coating layer faces up and maintains a preset spacing with the upper electrode. At the same time, the conductive surface contacts the lower electrode to form a flat electrode. Provide the necessary electrical connection and physical support for the detection process, and ensure the stable transmission of current and voltage during the detection process.

[0102] The detection start command is sent through the host computer, and the motion control module parses the command and converts it into the actual movement of the mechanical device. The robot arm holding the upper electrode is controlled to start moving according to the loaded detection path. The motion control module monitors the position and status of the upper electrode in real time. When it detects that the upper electrode completes all detection points according to the preset path, it triggers the return command. Under the control of the motion control module, the upper electrode safely returns to the starting point along the predetermined path or the shortest path to prepare for the next detection or enter the standby state. After completing the detection and returning to the starting point, the motion control module sends a detection completion command to the host computer through the communication interface, including detection status, timestamp and other information.

[0103] Whether the upper electrode generates tip discharge during its movement is related to the size of the pores in the coating. When the pores are small (meeting the porosity requirements), the breakdown capacity is insufficient to generate current pulses. When the pores are large, such as when obvious bubble defects and impurity defects appear, the insulation capacity of the pores is weaker than that of the coating material, and it can break down and generate tip discharge. The sensor or detection device records the discharge position (these positions correspond to areas where the porosity exceeds the set standard) and related information (such as discharge intensity) in real time, and forms detection data to be transmitted to the host computer. The host computer forms a detection report through analysis and collation to evaluate the coating quality of the substrate to be tested, so as to facilitate further analysis, processing and decision-making.

[0104] In summary, the present invention provides an insulating coating defect detection method and detection system, which forms a flat electrode by contacting the conductive surface of the substrate to be detected that is opposite to the coating surface with the lower electrode; the coating surface of the substrate to be detected is arranged relative to the upper electrode according to a preset spacing; a preset voltage is applied to the upper electrode so that the upper electrode can form a tip discharge; the motion control module is started, and the upper electrode is clamped to move according to a preset detection path, which can cover the coating surface of the substrate to be detected, wherein the detection path is generated according to the shape of the substrate to be detected and the characteristics of the coating surface; check whether there is a position where a tip discharge is generated on the coating surface, and the position where the tip discharge is generated indicates that the porosity of this position exceeds the set standard, and the position where the tip discharge is not generated indicates that the porosity of this position meets the set standard. The present invention performs defect detection on the coating that exceeds the porosity standard by tip discharge without destroying the coating, and performs a full range of defect detection on the coating according to the preset detection path, so that the defects of the product coating can be detected quickly and conveniently, and the defect detection efficiency is improved. Moreover, it can be used in large-scale production, which greatly reduces the time and cost of coating inspection.

[0105] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0106] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A method for detecting defects in insulating coatings, characterized in that: A test device for detecting the breakdown characteristics of an insulating medium, the test device comprising a vacuum chamber, a test platform and a motion control module being arranged in the vacuum chamber, the test platform comprising an upper electrode and a lower electrode being arranged opposite to each other, the upper electrode being a pointed electrode, the motion control module having a clamping portion capable of clamping the upper electrode for movement, the method comprising: Setting the air pressure in the vacuum chamber to a low vacuum condition; The conductive surface of the substrate to be tested opposite to the coating surface is brought into contact with the lower electrode to form a flat electrode, wherein the coating surface is a dense plasma corrosion resistant coating formed on the surface of the material by plasma spraying technology; The plated surface of the substrate to be detected is arranged opposite to the upper electrode at a preset distance, and the preset distance and the low vacuum condition meet the Thomson discharge condition; Applying a preset voltage to the upper electrode so that the upper electrode can form a tip discharge; Starting the motion control module to clamp the upper electrode and move it along a preset detection path, so as to cover the coating layer of the substrate to be detected, wherein the detection path is generated according to the shape of the substrate to be detected and the characteristics of the coating layer; Check whether there are locations where tip discharge occurs on the coating surface. Locations where tip discharge occurs indicate that the porosity at these locations exceeds the set standard, and locations where tip discharge does not occur indicate that the porosity at these locations meets the set standard.

2. The method for detecting defects in insulating coatings according to claim 1, characterized in that: The step of starting the motion control module and clamping the upper electrode to move along a preset detection path so as to cover the coating surface of the substrate to be detected includes: Loading a preset detection path into the motion control module in a specific format, the detection path including: coordinate points, speed and acceleration; The detection start instruction is inputted through a host computer connected to the test device, and the motion control module controls the clamping part clamping the upper electrode to move according to the detection path in response to the detection start instruction; When the upper electrode completes the detection according to the detection path, the motion control module controls the upper electrode to return to the starting point of the path, and outputs a detection completion instruction to feed back to the host computer.

3. The method for detecting defects in insulating coatings according to claim 1 or 2, characterized in that: The motion control module includes a photoelectric encoder. During the motion process, the photoelectric encoder can monitor the position and speed parameters of the upper electrode in real time and make adjustments according to actual needs to ensure that the upper electrode moves accurately along the detection path.

4. The method for detecting defects in insulating coatings according to claim 1 or 2, characterized in that: The motion control module includes: a first transmission mechanism and a second transmission mechanism, wherein the first transmission mechanism has a lateral motion control function, and the second transmission mechanism has a longitudinal motion control function, so as to achieve precise positioning of the upper electrode in a two-dimensional or three-dimensional space.

5. The method for detecting defects in insulating coatings according to claim 1, characterized in that: The step of generating the detection path according to the shape of the substrate to be detected and the characteristics of the coating layer includes: Acquire the three-dimensional shape data of the substrate to be inspected and the profile and size of the coating surface; Based on the three-dimensional shape data and the contour and size of the coating surface, one or more detection paths that can cover the entire coating surface are generated through a path simulation generation algorithm.

6. The method for detecting defects in insulating coatings according to claim 1, characterized in that: The porosity is set at a standard between 2% and 5%.

7. The method for detecting defects in insulating coatings according to claim 1, characterized in that: The method further comprises: The test device is evacuated or nitrogen is injected during evacuation to form a low-pressure environment.

8. The method for detecting defects in insulating coatings according to claim 1, characterized in that: The method further comprises: The upper electrode is set as a negative electrode, and the lower electrode is set as a positive electrode, so that a strong ionization area is formed near the upper electrode, which is conducive to the formation of a streamer and further reduces the corona starting voltage.

9. An insulation coating defect detection system, characterized in that: include: A test device for detecting the breakdown characteristics of an insulating medium, the test device comprising a vacuum chamber in which a test platform and a motion control module are arranged; The air pressure in the vacuum chamber is set to a low vacuum condition; The test platform comprises an upper electrode and a lower electrode arranged opposite to each other, wherein the upper electrode is a pointed electrode; The substrate to be detected includes a plated surface and a conductive surface that are arranged opposite to each other, the lower electrode contacts the conductive surface to form a flat electrode, the plated surface is arranged opposite to the upper electrode at a preset distance, the plated surface is a dense plasma corrosion resistant coating formed on the surface of the material by plasma spraying technology, and the preset distance and the low vacuum condition meet the Thomson discharge condition; The motion control module has a clamping portion, which can clamp the upper electrode to move along a preset detection path, and the detection path is generated according to the shape of the substrate to be detected and the characteristics of the coating layer to cover the coating layer of the substrate to be detected; A host computer is connected to the test device, and is used to control the operation of the test device and to transmit data and send control instructions.

10. The insulation coating defect detection system according to claim 9, characterized in that: The host computer is specifically used for: Setting the applied voltage of the electrodes, the preset spacing and the parameters of the detection path; receiving and displaying the detection data transmitted by the testing device, wherein the detection data includes the position information of the tip discharge generated on the coating surface; A defect detection report is generated according to the detection data to evaluate the coating quality of the substrate to be detected.

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