Parallel-plate open aperture electrode spacing self-adaptive adjustment method and system

Abstract

The application discloses a parallel-plate type aperture electrode interval self-adaptive adjusting method and system, and relates to the technical field of plasma surface treatment. The aperture electrode comprises two electrode plates which are oppositely arranged and each of which is provided with a plurality of through holes. The method divides the plate surface into a plurality of monitoring areas, each area corresponding to an adjusting member driven by a driving member; working voltage, inter-plate resistance, process gas flow rate and gas pressure are obtained, when the variation of any parameter relative to the reference value exceeds the threshold, the area ratio of the through holes of the two plates in each area and the current interval are obtained; the target interval of each area is determined according to the difference of the area ratio of the through holes of the two plates, and the corresponding electrode plate is driven to move to the target interval; before the interval is changed, the electrode plate is translated or rotated in the plate surface according to the gas flow resistance and discharge capacity, and the overlapping area of the through holes of the two plates is adjusted. The application can independently adjust the electrode interval in different areas and cooperatively adjust the aperture overlapping degree.

Description

Technical Field

[0001] This application relates to the field of plasma surface treatment technology, and more specifically, to a method and system for adaptive adjustment of the spacing between parallel flat plate-type perforated electrodes. Background Technology

[0002] Vacuum plasma cleaners are commonly used for surface treatment in semiconductor packaging, printed circuit boards, automotive parts, medical devices, and optical components. These machines consist of two parallel electrode plates positioned opposite each other within a vacuum chamber. One electrode plate is connected to a radio frequency (RF) power supply, while the other is grounded. During operation, the chamber is first evacuated to a low pressure, and then a process gas, such as argon, oxygen, nitrogen, or a mixture thereof, is introduced. After applying an RF voltage between the two electrode plates, the process gas is ionized to generate plasma. The plasma's ions, electrons, and free radicals bombard the workpiece surface between the plates, thus achieving cleaning, activation, etching, or grafting processes.

[0003] In the aforementioned equipment, the electrode plates typically have an array of through-holes. Process gas flows into the inter-plate discharge region through the through-holes on one side of the electrode plate, causing the gas to be uniformly distributed along the plate surface, thereby generating plasma uniformly on the plate surface. The distance between the two electrode plates determines the electric field strength between the plates, and together with the gas pressure inside the cavity, it determines the gas breakdown characteristics, which are key parameters affecting plasma density, discharge uniformity, and radio frequency matching status.

[0004] During long-term operation of the device, the distance between the two electrode plates is not constant. The heat generated by the continuous injection of radio frequency power causes thermal expansion of the electrode plates; the low pressure inside the cavity and the atmospheric pressure outside the cavity cause the electrode plates to be subjected to continuous pressure and flexural deformation; repeated heating and cooling cycles cause creep of the electrode plate material; and during long-term operation, the electrode surface will also be etched by plasma or have reaction products deposited, changing the surface morphology. The combination of these factors causes the actual distance between the plates to continuously drift.

[0005] If the spacing deviates from the design value, the electric field strength between the plates changes accordingly, and the plasma density distribution along the plate surface becomes uneven, leading to inconsistent processing results for the same batch of workpieces, manifesting as incomplete cleaning or excessive etching in certain areas. In areas where the spacing is too small, an excessively strong electric field can cause glow discharge to transform into arc discharge, resulting in burns on the workpiece surface. At the same time, changes in the plasma equivalent impedance can cause mismatch between the RF power supply and the load, increasing reflected power, decreasing energy utilization, and in severe cases, damaging the RF power supply.

[0006] Existing plasma cleaning equipment mostly employs a fixed-spacing structure, meaning the electrode plates cannot be adjusted once positioned during assembly. Because the cavity is a vacuum environment, adjusting the spacing requires breaking the vacuum, opening the cavity, and reassembling, resulting in lengthy downtime and high maintenance costs. Maintenance is typically only performed after a certain number of operating cycles, making it impossible to respond promptly to changes in operating conditions. Some equipment incorporates an overall adjustment mechanism, using shims or lead screws to move one electrode plate as a whole, synchronously increasing or decreasing the spacing between plates. However, the gas flow field, temperature field, and plasma density distribution along the plate surface are not uniform, and the thermal deformation and surface etching of the electrode plates often exhibit localized effects, with different spacing drifts occurring in different areas of the plate. If the entire plate is moved at this point, areas with excessively large spacing are not yet adjusted, while areas with insufficient spacing are further compressed, leading to a situation where some areas are not properly adjusted while others are not.

[0007] A more prominent problem is that after through-holes are opened on the electrode plates, the relative positions of the through-holes on the two electrode plates simultaneously affect two coupled indicators. When the through-holes on the two electrode plates tend to align, the process gas can flow directly into the through-hole on one side after entering the through-hole on the other side, resulting in low airflow resistance and uniform gas distribution along the plate surface. However, the physical area of ​​the two electrode plates facing each other decreases, thus reducing the effective discharge area, increasing plasma impedance, and weakening the discharge. Conversely, when the through-holes on the two electrode plates tend to be staggered, the physical area of ​​the two plates facing each other increases, increasing the effective discharge area, decreasing plasma impedance, and enhancing the discharge. However, the process gas must detour, increasing airflow resistance and worsening the uniformity of distribution. Existing adjustment schemes only focus on changing the single degree of freedom of the spacing, without incorporating the overlap of the opening areas of the two electrode plates into the adjustment method. Therefore, while improving the uniformity of airflow distribution, it often weakens the discharge capacity, and while enhancing the discharge capacity, it leads to a deterioration of the airflow distribution. It is difficult to achieve both indicators simultaneously.

[0008] In addition, the existing solution lacks a closed-loop mechanism that automatically determines when to adjust, which area to adjust, and how much to adjust based on real-time operating conditions. The determination of adjustment timing and amount relies on human experience and periodic shutdowns, which cannot respond to sudden changes in operating conditions in a timely manner and is also prone to introducing new deviations due to inappropriate adjustment ranges. Summary of the Invention

[0009] The purpose of this application is to provide a method and system for adaptive adjustment of the spacing between parallel plate-type perforated electrodes. This method and system can independently adjust the electrode spacing according to the monitoring area and coordinately adjust the overlap of the perforated areas of the two electrode plates. This improves the uniformity of process gas distribution, enhances the consistency of plasma treatment, and improves the stability of equipment operation while ensuring discharge capacity.

[0010] This application provides a method for adaptive adjustment of the spacing between parallel flat-plate perforated electrodes. The perforated electrodes include a first electrode plate and a second electrode plate disposed opposite to each other, and both electrode plates have multiple through holes. The method includes: The surfaces of the two electrode plates are divided into multiple monitoring areas, and each monitoring area corresponds to at least one adjustment element driven by a driving element alone. The operating voltage of the perforated electrode, the resistance between the two electrode plates, and the flow rate and pressure of the fluid flowing through the through hole are obtained. When the change of at least one of the operating voltage, the resistance, the flow rate and the pressure relative to the reference value exceeds the corresponding threshold, the percentage of the through-hole area of ​​the first electrode plate, the percentage of the through-hole area of ​​the second electrode plate and the current distance between the two electrode plates are obtained in each monitoring area. For each monitoring area, the target spacing of the monitoring area is determined based on the difference in the area ratio of the two through holes in the monitoring area, and the moving direction and moving distance of the corresponding adjustment component are determined based on the target spacing and the current spacing. The driving components are controlled to drive the corresponding adjusting components to move the electrode plates, so that the distance between the two electrode plates in each monitoring area reaches the corresponding target distance.

[0011] Furthermore, the method also includes: The resistance between the first electrode plate and the second electrode plate in each monitoring area is obtained as the local resistance of that monitoring area; The flow velocity of the fluid after passing through the through-hole in each monitoring area is obtained as the local flow velocity of that monitoring area.

[0012] Furthermore, the corresponding threshold includes an overall threshold and a local threshold; When the change in at least one of the operating voltage, the resistance, the flow rate and the pressure relative to the reference value exceeds the overall threshold, the target spacing is determined for all monitoring areas and the corresponding drive unit is controlled. When the change in local resistance in any monitoring area exceeds the local threshold, or the change in local flow velocity in the monitoring area exceeds the local threshold, the target spacing is determined only for that monitoring area and the corresponding drive unit is controlled.

[0013] Furthermore, obtaining the percentage of the through-hole area of ​​the first electrode plate and the percentage of the through-hole area of ​​the second electrode plate within each monitoring area includes: For each monitoring area, obtain the aperture of the through holes within that monitoring area and the hole spacing between adjacent through holes; The sum of the areas of the through holes per unit area within the monitoring area is determined based on the aperture and the hole spacing, and the ratio of the sum of the areas to the unit area is determined as the proportion of the through hole area of ​​the corresponding electrode plate within the monitoring area.

[0014] Further, determining the target spacing of the monitoring area based on the difference in the area ratio of the two through holes within the monitoring area includes: The larger of the percentage of the through-hole area of ​​the first electrode plate and the percentage of the through-hole area of ​​the second electrode plate within the monitoring area is determined as the opening characteristic value of the monitoring area. The target spacing of the monitoring area is determined based on the opening feature value and the difference. The target spacing decreases as the opening feature value increases and decreases as the absolute value of the difference increases.

[0015] Furthermore, the corresponding adjusting member is an adjusting member that bears displacement, and is determined as follows: When the proportion of the through-hole area of ​​the first electrode plate in the monitoring area is greater than that of the through-hole area of ​​the second electrode plate, the corresponding adjusting component is an adjusting component acting on the second electrode plate. When the proportion of the through-hole area of ​​the first electrode plate in the monitoring area is less than that of the through-hole area of ​​the second electrode plate, the corresponding adjusting component is an adjusting component acting on the first electrode plate. When the proportion of the through-hole area of ​​the first electrode plate is equal to the proportion of the through-hole area of ​​the second electrode plate, the corresponding adjusting member is an adjusting member that acts on both the first electrode plate and the second electrode plate simultaneously.

[0016] Furthermore, each monitoring area corresponds to at least two adjustment elements, one of which acts on the first electrode plate and the other of which acts on the second electrode plate; The driving component is an electrically controlled displacement driving component, and each driving component drives one of the adjusting components individually; under the drive of its corresponding driving component, the adjusting component drives the electrode plate it acts on to move in a direction perpendicular to the plate surface.

[0017] Furthermore, before controlling each of the driving components to drive the corresponding adjusting components to move the electrode plate, the method further includes: When the flow rate is less than the set flow rate and the pressure is greater than the set pressure, the fluid resistance is determined to be too high; when the flow rate is greater than or equal to the set flow rate, or the pressure is less than or equal to the set pressure, the fluid resistance is determined to be normal. When the resistance is less than the set resistance, the conductivity is determined to be sufficient; when the resistance is greater than or equal to the set resistance, the conductivity is determined to be insufficient. When the fluid resistance is high and the conductivity is sufficient, the first electrode plate or the second electrode plate is driven to translate or rotate within its own plate surface, thereby increasing the overlap area between the through holes of the first electrode plate and the through holes of the second electrode plate. When the fluid resistance is normal and the conductivity is insufficient, the first electrode plate or the second electrode plate is driven to translate or rotate within its own plate surface, thereby reducing the overlapping area.

[0018] Furthermore, after driving the first electrode plate or the second electrode plate to translate or rotate within its own surface, the method further includes: Reacquire the local resistance and local flow velocity for each monitoring area; For monitoring areas where both the change in local resistance and the change in local flow velocity are less than or equal to a set change, the distance between the two electrode plates in the monitoring area remains unchanged, and the driving device corresponding to the monitoring area is not controlled. For a monitoring area where at least one of the changes in local resistance and the changes in local flow velocity is greater than the set change, the driving component corresponding to the monitoring area is controlled to drive the corresponding adjusting component to move the electrode plate, so that the distance between the two electrode plates in the monitoring area reaches the target distance of the monitoring area.

[0019] Furthermore, this application also provides a parallel flat plate type open electrode spacing adaptive adjustment system, wherein the open electrode includes a first electrode plate and a second electrode plate arranged opposite to each other, and both electrode plates are provided with multiple through holes, including: The adjustment assembly includes multiple adjustment elements and multiple driving elements corresponding one-to-one with the multiple adjustment elements; the surfaces of the two electrode plates are divided into multiple monitoring areas, and each monitoring area corresponds to at least one adjustment element individually driven by the corresponding driving element; The parameter acquisition component includes a voltage detection device, a resistance detection device, a flow rate detection device, and a pressure detection device, which are used to acquire the working voltage of the open electrode, the resistance between the two electrode plates, and the flow rate and pressure of the fluid flowing through the through hole, respectively. The controller, connected to the parameter acquisition component and each of the driving components, is used for: When the change in at least one of the operating voltage, the resistance, the flow rate and the pressure relative to the reference value exceeds the corresponding threshold, the percentage of the through-hole area of ​​the first electrode plate, the percentage of the through-hole area of ​​the second electrode plate and the current spacing between the two electrode plates are obtained in each monitoring area. For each monitoring area, the target spacing of the monitoring area is determined based on the difference in the area ratio of the two through holes in the monitoring area, and the moving direction and moving distance of the corresponding adjusting component are determined based on the target spacing and the current spacing. The driving components are controlled to drive the corresponding adjusting components to move the electrode plates, so that the distance between the two electrode plates in each monitoring area reaches the corresponding target distance.

[0020] As can be seen from the above, the parallel plate-type open electrode spacing adaptive adjustment method and system provided in this application divides the electrode plate surface into multiple monitoring areas and configures an adjustment component driven by a driving component for each monitoring area. The target spacing is determined according to the difference in the area ratio of the through holes of the two electrode plates in each monitoring area, and the corresponding electrode plates are driven to move independently. Before changing the electrode spacing, the electrode plates are driven to translate or rotate within their own plate surface according to the airflow resistance and discharge capacity to adjust the overlap area between the through holes of the two electrode plates. This solves the problem that the uneven distribution of the electrode spacing along the plate surface and the difficulty in synergistically suppressing the uneven plasma density and radio frequency mismatch caused by the coupling between the uniformity of process gas distribution and discharge capacity during the operation of the vacuum plasma cleaner are due to the electrode spacing drift. It has the advantages of being able to independently adjust the electrode spacing according to the monitoring area and synergistically adjust the overlap of the open areas of the two electrode plates, thereby improving the uniformity of process gas distribution, improving the consistency of plasma treatment and the stability of equipment operation while ensuring the discharge capacity. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a flowchart illustrating the steps of the adaptive adjustment method for the spacing of parallel flat-plate perforated electrodes disclosed in the embodiments of this application. Figure 2 This is a flowchart illustrating the steps for determining the corresponding adjustment element as disclosed in an embodiment of this application; Figure 3 This is a schematic diagram of the adaptive adjustment system for the spacing of parallel flat-plate perforated electrodes disclosed in an embodiment of this application. Detailed Implementation

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which these embodiments belong; the terminology used herein and in the specification of the application is for the purpose of describing particular embodiments only and is not intended to limit these embodiments; the terms "comprising" and "having," and any variations thereof, in the specification of these embodiments and the foregoing drawings, are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification of these embodiments and the foregoing drawings are used to distinguish different objects, not to describe a particular order.

[0024] The implementation details of the technical solution in this embodiment are described in detail below: This application proposes an adaptive adjustment method for the spacing of parallel flat-plate perforated electrodes. The perforated electrodes include a first electrode plate and a second electrode plate arranged opposite to each other, and both electrode plates have multiple through holes.

[0025] like Figure 1 As shown, the method includes: S101, the surfaces of the two electrode plates are divided into multiple monitoring areas, and each monitoring area corresponds to at least one adjustment element driven by a driving element alone.

[0026] In one implementation, the surfaces of the first and second electrode plates facing each other are used as the dividing objects. The surfaces are divided at equal intervals along two orthogonal directions to obtain N rectangular monitoring areas in m rows and n columns, where N = m × n. When the electrode plate surface is circular, the above division is first performed according to its circumscribed rectangle. Then, the intersection of the resulting rectangular areas with the circular plate surface is calculated, and the intersecting portion is taken as the effective monitoring area. In this case, the number of effective monitoring areas is less than N. Alternatively, the monitoring area can be divided using concentric circles and radial rays centered on the plate surface to obtain a ring-shaped sector-shaped monitoring area.

[0027] Let the area of ​​the two electrode plates be S0, and the area of ​​a single monitoring region be Sa. Then Sa = S0 ÷ N. The number of rows m and columns n are determined based on the plate size and the flow field gradient. The larger the plate size or the steeper the gradient of the flow field along the plate, the larger the values ​​of m and n, so that the operating conditions within a single monitoring region are approximately consistent.

[0028] In another implementation, the monitoring area is not divided at equal intervals, but rather according to the arrangement period of the through-hole array on the two electrode plates, ensuring that the number of through-holes in each monitoring area is the same or nearly the same. When divided in this way, the proportion of through-hole area in each monitoring area is on the same order of magnitude, facilitating subsequent lateral comparison of the target spacing between different monitoring areas.

[0029] Each monitoring area corresponds to at least one adjusting element driven independently by a drive element. This means that each monitoring area is equipped with an independent displacement execution link, which consists of a drive element and an adjusting element connected in series. Each drive element only drives the adjusting element connected to it, and the adjusting elements in different monitoring areas are not involved in each other's movements. Therefore, when the electrode spacing of a certain monitoring area is changed, the electrode spacing of adjacent monitoring areas is not affected, and differential adjustment can be achieved between different areas of the plate.

[0030] In one implementation, each monitoring area corresponds to two adjusting components, one of which acts on the first electrode plate and the other on the second electrode plate. Each adjusting component is driven independently by a driving component. Thus, when determining which electrode plate should bear the displacement, both electrode plates have independently drivable actuators.

[0031] The driving component is an electrically controlled displacement drive, which means that the drive converts the received electrical signal into a linear displacement output. Specifically, it can be any of the following: a combination of a stepper motor and a lead screw, a voice coil motor, or a piezoelectric ceramic actuator. After receiving the displacement command from the controller, the drive outputs a linear displacement proportional to the command. Driven by this displacement, the adjusting component pushes the electrode plate it acts upon to move in a direction perpendicular to the plate surface.

[0032] S102, obtain the working voltage of the open electrode, the resistance between the two electrode plates, and the flow rate and pressure of the fluid flowing through the through hole.

[0033] The above four quantities are collected synchronously according to the sampling period Ts after the plasma stabilizes and discharges. That is, sampling begins after the RF power supply ignites and the process gas in the cavity enters a stable glow discharge state. The quantities collected during the ignition process and the power adjustment transition phase are not included in the calculation of the reference value and the change. The working voltage U is collected by a voltage sampling circuit connected in parallel between the two electrode plates. The working voltage U here is the effective value of the RF voltage between the two electrode plates, which is obtained by the RF voltage sampling circuit and then by the effective value conversion circuit. The RF voltage sampling circuit can use a capacitive voltage divider sampling probe or a RC voltage divider network. The inter-plate resistance R is obtained as follows: first, the impedance magnitude Z = Urms ÷ Irms is calculated from the effective value of the RF voltage Urms and the effective value of the RF current Irms between the two electrode plates. Then, its resistance component is taken as the inter-plate resistance, i.e., R = Z × cosφ, where φ is the phase difference between the RF voltage and the RF current, which is measured by the phase detection circuit. When the phase difference is negligible, R = Urms ÷ Irms is directly taken. The flow rate v of the process gas is obtained by converting the volumetric flow rate measured by the gas mass flow meter installed on the gas inlet passage, and is calculated according to v = Qv ÷ Sg, where Qv is the volumetric flow rate measured by the mass flow meter, and Sg is the sum of the flow areas of all through holes on the side electrode plate; the gas pressure P in the cavity is collected by the vacuum gauge connected to the vacuum cavity, and its unit is Pascal or Torr.

[0034] Each sampling yields four values ​​that constitute a sampling point and are written into a buffer queue. The length of the buffer queue is denoted as Lc. The controller maintains the queue in a first-in-first-out manner, so that the values ​​of the most recent Lc sampling points can be traced back at any time.

[0035] Furthermore, the method also includes: obtaining the resistance between the first electrode plate and the second electrode plate in each monitoring area as the local resistance of the monitoring area; and obtaining the flow velocity of the fluid after flowing through the through hole in each monitoring area as the local flow velocity of the monitoring area.

[0036] For the i-th monitoring region, where i ranges from 1 to N, the local resistance of this region is denoted as Ri, and the local flow velocity as vi. The local resistance Ri is measured by setting a pair of voltage probes within each monitoring region. These probes are electrically connected to the surfaces of the first and second electrode plates within that region. The voltage drop across the monitoring region is measured and divided by the current flowing through it to obtain Ri. The current flowing through the i-th monitoring region is denoted as Ii. In the embodiment where the two electrode plates are powered separately according to the monitoring regions, each monitoring region is powered by an independent power supply branch, and Ii is directly measured by a current detection unit connected in series on that branch. In the embodiment where the two electrode plates are powered as a whole, the total current I is distributed according to the area ratio of each monitoring region, i.e., Ii = I × Sa ÷ S0. Correspondingly, the local resistance is calculated as Ri = Ui ÷ Ii, where Ui is the voltage drop measured by the pair of voltage probes. The local flow velocity vi is measured by setting a flow velocity detection unit on the fluid outlet side of each monitoring region.

[0037] Inter-plate resistance R and local resistance Ri complement each other in characterizing the same object. Inter-plate resistance R reflects the overall conductivity between the two electrode plates, while local resistance Ri reflects the conductivity within the i-th monitoring region. When the conductivity is consistent across the plate surface, the values ​​of each Ri are close to each other and close to R. However, when surface etching is intensified, reaction products are deposited, or the electrode is locally deformed in a certain area, the Ri in that area will deviate significantly from R, while the inter-plate resistance R may not change significantly due to compensation from other areas. Therefore, the inter-plate resistance R alone cannot locate the abnormal monitoring area; it is necessary to combine the values ​​of each Ri to determine the location of the abnormal area.

[0038] S103, when the change of at least one of the working voltage, the resistance, the flow rate and the pressure relative to the reference value exceeds the corresponding threshold, the percentage of the through-hole area of ​​the first electrode plate, the percentage of the through-hole area of ​​the second electrode plate and the current distance between the two electrode plates are obtained in each monitoring area. Let parameter X take the value X1 in this sampling, and its reference value be X0. The change of parameter X relative to the reference value is denoted as ΔX, and calculated as ΔX = |X1 - X0| ÷ X0. ΔX is a dimensionless quantity, representing the degree of deviation of parameter X from the reference value. The reference value X0 is obtained by averaging the values ​​of the most recent Lc sampling points in the buffer queue after the aperture electrode has been running stably under the design conditions for a period of time, i.e., X0 = (Xc1 + Xc2 + ... + XcLc) ÷ Lc, where Xck represents the value corresponding to the k-th sampling point in the buffer queue.

[0039] The baseline value X0 is established and updated as follows: At the initial stage of operation of the orifice electrode, Lc sampling points are continuously collected. If the change between any two adjacent sampling points in these Lc sampling points is less than the stability criterion εs, the orifice electrode is considered to have entered a stable operating condition, and the average value of these Lc sampling points is taken as the baseline value for each parameter. During subsequent operation, the baseline value is refreshed in the same manner after each round of spacing adjustment and re-entry into a stable operating condition. Using a rolling refresh method allows the baseline value to be updated synchronously with slow drift factors such as electrode aging and changes in fluid properties, avoiding frequent false triggers due to outdated baseline values ​​after long-term operation.

[0040] The operating voltage, resistance, flow rate, and pressure each correspond to a pre-set dimensionless threshold, denoted as εu, εr, εv, and εp, respectively. When at least one of ΔU>εu, ΔR>εr, Δv>εv, or ΔP>εp is true, the subsequent spacing adjustment process is triggered; otherwise, the current spacing of each monitoring area remains unchanged, and sampling continues.

[0041] Furthermore, the corresponding threshold includes an overall threshold and a local threshold; When the change in at least one of the operating voltage, the resistance, the flow rate and the pressure relative to the reference value exceeds the overall threshold, the target spacing is determined for all monitoring areas and the corresponding drive unit is controlled. When the change in local resistance in any monitoring area exceeds the local threshold, or the change in local flow velocity in the monitoring area exceeds the local threshold, the target spacing is determined only for that monitoring area and the corresponding drive unit is controlled.

[0042] Specifically, the overall threshold is used to determine whether the overall operating condition of the orifice electrode has deviated. The aforementioned εu, εr, εv, and εp are the overall thresholds. When the change in at least one of the operating voltage, resistance, flow rate, and pressure exceeds its overall threshold, it indicates that the overall spacing between the two electrode plates has deviated from the design value. At this time, the target spacing is determined for all monitoring areas and the corresponding drive is controlled, that is, the spacing adjustment is performed one by one for the 1st to the Nth monitoring areas.

[0043] Local thresholds are used to determine whether the operating conditions of a single monitoring area have deviated. The local threshold corresponding to local resistance is denoted as εrl, and the local threshold corresponding to local flow velocity is denoted as εvl. For the i-th monitoring area, the change in local resistance ΔRi = |Ri1 - Ri0| ÷ Ri0, and the change in local flow velocity Δvi = |vi1 - vi0| ÷ vi0, where Ri0 and vi0 are the reference values ​​of local resistance and local flow velocity for that monitoring area, respectively, and their determination method is the same as that of X0 mentioned above. When ΔRi>εrl or Δvi>εvl is true, the target spacing is determined only for the i-th monitoring area and the corresponding drive unit is controlled, while the current spacing remains unchanged for the other monitoring areas.

[0044] Setting up two levels of judgment, namely overall threshold and local threshold, allows for unified adjustment of all monitoring areas when the overall situation deviates, and adjustment only for the abnormal areas when only a few areas are abnormal. This ensures timely adjustment and avoids unnecessary changes to monitoring areas with normal operating conditions, which could introduce new deviations.

[0045] Furthermore, obtaining the through-hole area ratio of the first electrode plate and the through-hole area ratio of the second electrode plate in each monitoring area includes: for each monitoring area, obtaining the aperture of the through-hole in the monitoring area and the hole distance between adjacent through-holes; determining the sum of the areas of through-holes per unit area in the monitoring area based on the aperture and the hole distance, and determining the ratio of the sum of the areas to the unit area as the through-hole area ratio of the corresponding electrode plate in the monitoring area.

[0046] Specifically, let φ be the diameter of a single through hole, and p be the distance between the centers of two adjacent through holes. When the through holes are arranged in a square array, the number of through holes per unit area is n0 = 1 ÷ p², and the area of ​​a single through hole is s0 = π × φ² ÷ 4. Then, the proportion of the through hole area α in the monitoring area is calculated as α = n0 × s0 = π × φ² ÷ (4 × p²).

[0047] For example, if the diameter φ of the through holes in a certain monitoring area is 2 mm and the hole spacing p is 5 mm, then the area ratio of the through holes in the monitoring area is α = 3.14 × 2² ÷ (4 × 5²) = 12.56 ÷ 100 = 0.126, or 12.6%.

[0048] When the vias are arranged in an equilateral triangle array, the area occupied by each via is... The number of through holes per unit area, n0 = 2 ÷ ( × p²), and correspondingly, the area ratio of the through holes α = π × φ² ÷ (2 × × p²).

[0049] The through-hole area ratio α determines both the effective discharge area and the process gas flow capacity of the monitoring region. A larger α indicates less solid portion of the electrode plate within the monitoring region, resulting in a smaller effective discharge area and less resistance to process gas flow. Therefore, α is a quantity that links the discharge state with the gas flow state, and it is also the direct basis for subsequently determining the target spacing.

[0050] For the i-th monitoring area, let α1i be the area ratio of the through holes of the first electrode plate and α2i be the area ratio of the through holes of the second electrode plate. Both are calculated as described above. Let di be the current distance between the two electrode plates in the monitoring area. This current distance is directly measured by the displacement detection unit set in the monitoring area, or it can be calculated from the cumulative output displacement of the driving component corresponding to the monitoring area.

[0051] The displacement detection unit can use any one of laser displacement sensor, capacitive displacement sensor or eddy current displacement sensor; when using laser displacement sensor, it performs non-contact measurement on the back of electrode plate through an observation window opened on the wall of vacuum cavity; when using capacitive or eddy current displacement sensor, its probe is fixed to the inner wall of cavity and set opposite to the back of electrode plate, and the probe lead is led out through vacuum seal feedthrough.

[0052] S104, for each monitoring area, the target spacing of the monitoring area is determined based on the difference in the area ratio of the two through holes in the monitoring area, and the moving direction and moving distance of the corresponding adjusting member are determined based on the target spacing and the current spacing. Furthermore, determining the target spacing of the monitoring area based on the difference between the area ratios of the two through holes within the monitoring area includes: determining the larger of the area ratio of the through holes of the first electrode plate and the area ratio of the through holes of the second electrode plate within the monitoring area as the opening feature value of the monitoring area; determining the target spacing of the monitoring area based on the opening feature value and the difference, wherein the target spacing decreases as the opening feature value increases and decreases as the absolute value of the difference increases.

[0053] Specifically, for the i-th monitoring area, its aperture characteristic value is denoted as αi, determined by αi = max(α1i, α2i), which is the larger of the through-hole area ratio α1i of the first electrode plate and the through-hole area ratio α2i of the second electrode plate within the monitoring area. The aperture characteristic value αi represents the upper limit of the aperture degree of the two electrode plates within the monitoring area. The larger αi is, the less solid part at least one electrode plate in the monitoring area has.

[0054] The difference in the area ratio of the two through holes within the monitoring area is denoted as δi, and calculated as δi = α1i - α2i. The absolute value of δi, |δi|, characterizes the degree of asymmetry in the opening degree of the two electrode plates within the same monitoring area. The larger |δi| is, the greater the difference in the effective conductive area of ​​the two electrode plates within the monitoring area, and the more uneven the electric field distribution.

[0055] The target spacing of the monitoring area is denoted as Di, and is determined by Di = max(D0 - k1 × αi - k2 × |δi|, Dmin). Here, D0 is the reference spacing between the two electrode plates under the design conditions, predetermined by the structural parameters of the perforated electrode; k1 is the spacing compensation coefficient corresponding to the perforation characteristic value, and k2 is the spacing compensation coefficient corresponding to the percentage difference; both are positive numbers with length dimensions, obtained through experimental calibration or simulation fitting. In one calibration method, two monitoring areas with different perforation characteristic values ​​and percentage differences are selected as calibration points. The spacing required for the local resistance of these two monitoring areas to reach the target value is measured, and these spacings, along with their corresponding αi and |δi|, are substituted into D0 - k1 × αi - k2 × |δi| = Di to obtain a system of two linear equations about k1 and k2. Solving this system of equations yields the values ​​of k1 and k2. When there are more than two calibration points, k1 and k2 are obtained by least squares fitting. Dmin is a preset minimum allowable distance used to prevent the two electrode plates from coming into contact during adjustment and causing a short circuit. In one implementation, Dmin is determined by Dmin = U ÷ Emax, where U is the working voltage between the two electrode plates and Emax is the breakdown field strength of the fluid, thereby ensuring that the fluid medium is not broken down under the minimum allowable distance.

[0056] As shown in the above equation, Di decreases as αi increases, and Di also decreases as |δi| increases. This means the target spacing decreases with increasing aperture characteristic value, and also decreases with increasing absolute value of the difference. This correspondence is adopted because the larger the aperture, the smaller the conductive area and the weaker the electric field within the monitoring region. Shortening the distance between the two electrode plates can increase the electric field strength in this region, thus compensating for the conductivity loss due to the aperture. Similarly, the more asymmetrical the apertures on the two electrode plates, the more uneven the electric field distribution within the monitoring region. Similarly, shortening the spacing is necessary to suppress the lateral diffusion of the electric field within the plate surface. By introducing Dmin to constrain the lower limit of Di, it can be ensured that spacing compensation will not cause the two electrode plates to contact.

[0057] For example, taking D0 = 5 mm, k1 = 10 mm, k2 = 20 mm, Dmin = 1 mm, and α1i = 0.126, α2i = 0.106 in a certain monitoring area, then αi = 0.126, δi = 0.020. Substituting into the above formula gives Di = 5 - 10 × 0.126 - 20 × 0.020 = 5 - 1.26 - 0.40 = 3.34 mm. If the current spacing di of this monitoring area is 4.00 mm, the spacing needs to be reduced from 4.00 mm to 3.34 mm.

[0058] After the target spacing is determined, the moving distance of the adjusting member corresponding to this monitoring area is denoted as Δdi, which is calculated according to Δdi = |Di - di|. The moving direction is determined according to the magnitude relationship between Di and di: when Di < di, the moving direction is to drive the acted electrode plate to approach the other electrode plate; when Di > di, the moving direction is to drive the acted electrode plate to move away from the other electrode plate; when Di = di, this monitoring area does not need to move, and the corresponding driving member keeps the current output unchanged. According to the above calculation result, Di = 3.34 mm is less than di = 4.00 mm, so the moving direction is approaching, and the moving distance Δdi = 0.66 mm.

[0059] It should be noted that the moving direction includes two directions of approaching and moving away, which requires that the connection between the adjusting member and the electrode plate can transmit bidirectional acting force, rather than an abutting relationship that can only transmit unidirectional thrust. If the adjusting member only abuts against the side of the electrode plate facing away from the other electrode plate without forming a connection, the adjusting member can only push the electrode plate to approach but cannot drive it to move away, and this direction cannot be realized when Di > di.

[0060] Further, the corresponding adjusting member is an adjusting member that bears the displacement, as Figure 2 shown in the figure, which is a schematic flowchart of the steps for determining the corresponding adjusting member. The corresponding adjusting member is determined in the following manner: S2001, when the through-hole area proportion of the first electrode plate in this monitoring area is greater than the through-hole area proportion of the second electrode plate, the corresponding adjusting member is the adjusting member acting on the second electrode plate; S2002, when the through-hole area proportion of the first electrode plate in this monitoring area is less than the through-hole area proportion of the second electrode plate, the corresponding adjusting member is the adjusting member acting on the first electrode plate; S2003, when the through-hole area proportion of the first electrode plate is equal to the through-hole area proportion of the second electrode plate, the corresponding adjusting member is the adjusting member acting on both the first electrode plate and the second electrode plate at the same time.

[0061] S2001 to S2003 above are used to determine which adjusting element will perform the displacement before it is assumed. This determination is necessary because each monitoring area has two adjusting elements, acting on the first and second electrode plates respectively. If no selection is made and both adjusting elements output displacement simultaneously, the two electrode plates will move towards each other simultaneously, and the actual change in the distance between them within the monitoring area will be twice Δdi, which does not match the target distance.

[0062] For the i-th monitoring region, let the bending stiffness of the first electrode plate in this region be K1i, and that of the second electrode plate be K2i. Assuming the two electrode plates have the same thickness, material, and the same arrangement of the through-hole array, the bending stiffness can be approximated as being proportional to the area occupied by the solid portion within that region, i.e. K1i ÷ K2i = (1 - α1i) ÷ (1 - α2i) Where 1 - α1i represents the area proportion of the solid portion of the first electrode plate within the monitoring area, and 1 - α2i represents the area proportion of the solid portion of the second electrode plate within the monitoring area. This formula shows that the larger the proportion of the through-hole area, the smaller the corresponding solid area proportion, and the lower the bending stiffness.

[0063] Continuing with the example above, if α1i = 0.126 and α2i = 0.106 within a certain monitoring area, then... K1i ÷ K2i = (1 - 0.126) ÷ (1 - 0.106) = 0.874 ÷ 0.894 = 0.978 A ratio less than 1 indicates that the bending stiffness of the first electrode plate in the monitoring area is lower than that of the second electrode plate, meaning that the first electrode plate has more openings and is more prone to local warping near the pushing point.

[0064] When α1i > α2i, the proportion of the solid area of ​​the first electrode plate in the monitoring area is smaller than that of the second electrode plate, and its bending stiffness is lower than that of the second electrode plate. If the displacement is borne by the adjusting component acting on the first electrode plate, the first electrode plate is prone to local warping near the pushing point, causing the actual spacing change in the monitoring area to be less than Δdi, and the warping will introduce additional positional deviations between adjacent monitoring areas. Therefore, the displacement is instead borne by the adjusting component acting on the second electrode plate, i.e., pushing the electrode plate with higher stiffness towards the side with lower stiffness, with the displacement still being Δdi. According to the above example, the adjusting component acting on the second electrode plate should output a displacement of 0.66 mm in this monitoring area.

[0065] When α1i < α2i, the situation is the opposite of S2001. The bending stiffness of the second electrode plate in the monitoring area is lower than that of the first electrode plate. At this time, the corresponding adjustment component is the adjustment component acting on the first electrode plate, and the first electrode plate bears the displacement Δdi.

[0066] When α1i = α2i, the bending stiffness of the two electrode plates in the monitoring area is equivalent. Regardless of which side bears the displacement alone, their deformation is similar. At this point, the corresponding adjusting components are two adjusting components acting simultaneously on both the first and second electrode plates. In one implementation, each of the two adjusting components bears half of Δdi, i.e. Δd1i = Δd2i = Δdi ÷ 2 Where Δd1i is the displacement output by the adjusting mechanism acting on the first electrode plate, and Δd2i is the displacement output by the adjusting mechanism acting on the second electrode plate. When both adjusting mechanisms operate simultaneously, causing the two electrode plates to move closer together or further apart, each moving by Δdi ÷ 2, the change in spacing within the monitoring area remains Δdi. Following the aforementioned example and taking α1i = α2i = 0.126, each adjusting mechanism outputs a displacement of 0.33 mm, and the spacing within the monitoring area changes accordingly by 0.66 mm.

[0067] In another implementation, the displacement borne by the two adjusting components in S2003 is not distributed equally, but rather according to the ratio of the bending stiffness of the two electrode plates, i.e. Δd1i = Δdi × K1i ÷ (K1i + K2i) Δd2i = Δdi × K2i ÷ (K1i + K2i) From these two equations, it can be seen that the sum of Δd1i and Δd2i is still Δdi. When α1i is strictly equal to α2i, K1i = K2i, and both equations degenerate into Δdi ÷ 2, consistent with the equal division method; when the difference between α1i and α2i is less than the preset tolerance, the two equations give slightly different distribution results, with the side with higher stiffness bearing more displacement. This method makes the force on the two electrode plates tend to be balanced during the displacement process, and is suitable for open-hole electrodes with small plate thickness or large span.

[0068] By adopting a bidirectional load-sharing method, the displacement of a single output is reduced to half that of a single-sided load-sharing. The output stroke and output force of a single drive component are reduced accordingly, while avoiding the skew of the plate surface caused by excessive displacement on one side.

[0069] Furthermore, each monitoring area corresponds to at least two adjustment components, one of which acts on the first electrode plate and the other acts on the second electrode plate; the driving component is an electrically controlled displacement driving component, and each driving component drives one adjustment component individually; under the drive of its corresponding driving component, the adjustment component drives the electrode plate it acts on to move in a direction perpendicular to the plate surface.

[0070] Specifically, two adjusting elements are set in each monitoring area, so that regardless of which electrode plate needs to bear the displacement in that monitoring area, there is a corresponding actuator, and the three scenarios in S2001 to S2003 mentioned above can be directly executed. Each driving element drives one adjusting element independently, meaning that the driving elements are controlled independently. The controller can issue displacement commands to any one driving element without affecting the other driving elements, thereby realizing differential adjustment between the monitoring areas of the plate.

[0071] S105, control each of the driving components to drive the corresponding adjusting components to move the electrode plates, so that the distance between the two electrode plates in each monitoring area reaches the corresponding target distance.

[0072] In one implementation, the controller sends a displacement command to the drive unit corresponding to the area to be adjusted and monitored. This displacement command carries two quantities: the direction of movement and the distance of movement. The drive unit is an electrically controlled displacement drive unit, whose built-in displacement feedback unit detects the output displacement in real time and sends it back to the controller. The controller compares the output displacement with Δdi, and stops driving when the difference between the two is less than a preset tolerance, thereby forming a displacement closed loop and stabilizing the electrode spacing within the monitoring area at Di.

[0073] In another implementation, the controller does not rely on the displacement feedback built into the drive component. Instead, it directly reads the current distance di measured by the displacement detection unit within the monitoring area and stops driving when the absolute value of the difference between di and Di is less than a preset tolerance. This method uses the actual distance between the two electrode plates as the feedback quantity, which can eliminate the error caused by the transmission gap between the adjusting component and the electrode plates.

[0074] Regarding the adjustment timing of each monitoring area, in one implementation, the controller simultaneously issues displacement commands to all monitoring areas in the set to be adjusted, and each driving component executes synchronously to shorten the overall adjustment time; in another implementation, the controller issues displacement commands sequentially according to the monitoring area number, and adjusts the next monitoring area only after completing the adjustment of each monitoring area and confirming that its spacing reaches Di, so as to avoid impacting the power supply bus when multiple driving components operate simultaneously.

[0075] It should also be noted that dividing the plate surface into multiple monitoring areas and adjusting them separately is for situations where the target spacing between the monitoring areas differs. Since the first electrode plate and the second electrode plate are each continuous plates, when the adjustment amounts of adjacent monitoring areas are different, internal stress will be generated at the interface between the two areas. To ensure the differential adjustment of each monitoring area can be effectively implemented, in one implementation method, an upper limit is set for the difference in the target spacing change between adjacent monitoring areas, denoted as Δdmax. The value of Δdmax should also satisfy Δdmax ≤ D0 × Ct, where D0 is the reference spacing and Ct is a pre-set dimensionless proportionality coefficient with a value not greater than 0.2, to avoid excessively large differences in adjustment between adjacent areas, resulting in visible step differences at the boundary. When |Δdi - Δd(i+1)| ≤ Δdmax is satisfied between the i-th monitoring area and the (i+1)-th monitoring area, each monitoring area is adjusted independently according to its own target spacing. When the upper limit is exceeded, the target spacing change between two adjacent monitoring areas is averaged by Δd' = (Δdi + Δd(i+1)) ÷ 2 to make the displacement transition at the boundary smooth.

[0076] In another implementation, the change in target spacing of each monitoring area is smoothed according to its position on the board. That is, for the i-th monitoring area, the weighted average of its own and the changes of the adjacent monitoring areas is taken as the actual change amount. The weight decreases as the distance increases.

[0077] In another implementation, the controller issues displacement commands in batches according to the monitoring area number. Each batch contains only non-adjacent monitoring areas. After the adjustment of one batch is completed, the next batch is adjusted, so that the plate only needs to adapt to a small displacement gradient within any batch. Δdmax is determined by the allowable stress of the electrode plate material and the span of the monitoring area, specifically estimated as Δdmax = σs × Ls ÷ (Ee × Cs), where σs is the allowable stress of the electrode plate material, Ls is the distance between the centers of adjacent monitoring areas, Ee is the elastic modulus of the electrode plate material, and Cs is the dimensionless shape coefficient determined by the plate thickness and support method. All three are obtained from the design parameters of the electrode plate by looking up tables or simulation.

[0078] Furthermore, before controlling each of the driving components to drive the corresponding adjusting components to move the electrode plate, the method further includes: When the flow rate is less than the set flow rate and the pressure is greater than the set pressure, it is determined that the fluid resistance is on the high side; when the flow rate is greater than or equal to the set flow rate, or the pressure is less than or equal to the set pressure, it is determined that the fluid resistance is normal; when the resistance is less than the set resistance, it is determined that the conductivity is sufficient; when the resistance is greater than or equal to the set resistance, it is determined that the conductivity is insufficient; when the fluid resistance is on the high side and the conductivity is sufficient, the first electrode plate or the second electrode plate is driven to translate or rotate within its own plate surface, so as to increase the overlapping area between the through holes of the first electrode plate and the through holes of the second electrode plate; when the fluid resistance is normal and the conductivity is insufficient, the first electrode plate or the second electrode plate is driven to translate or rotate within its own plate surface, so as to reduce the overlapping area.

[0079] Specifically, the set flow rate is denoted as vs, the set pressure is denoted as Ps, and the set resistance is denoted as Rs, all three of which are preset constants. The determination method for fluid resistance is: when the flow rate v<vs and the pressure P>Ps, it is determined that the fluid resistance is on the high side; when v ≥ vs or P ≤ Ps, it is determined that the fluid resistance is normal. The reason for examining both the flow rate and the pressure at the same time is that under the same driving condition, an increase in fluid resistance will manifest as both a decrease in flow rate and an increase in pressure on the inlet side, and relying on only one of the quantities is susceptible to interference from flow fluctuations leading to misjudgment.

[0080] In one implementation, the gas flow resistance can also be quantified by the gas pressure difference across the two electrode plates, that is, a vacuum gauge is respectively arranged on the gas inlet side and the gas outlet side of the process gas, the gas pressure on the inlet side is denoted as Pin, and the gas pressure on the outlet side is denoted as Pout, then the gas flow resistance is characterized by ΔPg = Pin - Pout; a larger ΔPg indicates a higher gas flow resistance, based on which the criterion corresponding to the set pressure Ps can be directly set.

[0081] The determination method for conductivity is: when the inter-plate resistance R<Rs, it is determined that the conductivity is sufficient; when R ≥ Rs, it is determined that the conductivity is insufficient. The smaller the inter-plate resistance R is, the lower the impedance of the conductive path between the two electrode plates is, and the larger the conductive margin is.

[0082] The above two judgment results constitute four combinations. When fluid resistance is normal and conductivity is sufficient, the perforated electrode is near the design operating condition and requires no adjustment. When fluid resistance is high but conductivity is insufficient, the two indicators conflict. In this case, conductivity is prioritized, the overlapping area is not adjusted temporarily, the current relative position of the two electrode plates is maintained, and the conflict status is reported to the host computer. The judgment is re-executed after the operating condition recovers automatically or manual intervention is required. When fluid resistance is high and conductivity is sufficient, it indicates that conductivity is still sufficient but the flow channel is not smooth. In this case, the overlapping area is increased, that is, the through holes on the two electrode plates tend to align, the flow channel tends to be straight, and the fluid resistance decreases accordingly. When fluid resistance is normal but conductivity is insufficient, it indicates that the flow channel is smooth but the conductive area is insufficient. In this case, the overlapping area is decreased, that is, the through holes on the two electrode plates tend to be offset, the solid area of ​​the two electrode plates facing each other increases, and the conductivity increases accordingly.

[0083] The overlapping area between the through holes of the first electrode plate and the second electrode plate is denoted as Aov, which refers to the total area of ​​the overlapping portions of the projections of the through holes on the two electrode plates in the direction perpendicular to the plate surface. The larger Aov is, the easier it is for fluid to directly enter the through hole on the other side after passing through one side, and the smaller the fluid resistance. At the same time, the smaller the solid area of ​​the two electrode plates facing each other, the larger the inter-plate resistance R. Therefore, Aov is a quantity that inversely couples fluid resistance and conductivity. Adjusting Aov is to make a trade-off between fluid resistance and conductivity.

[0084] The first or second electrode plate is moved or rotated within its own surface by a planar adjustment actuator. The planar adjustment actuator can be either a vacuum-compatible electric slide or a piezoelectric-driven flexible platform. When using an electric slide, a stepper motor located outside the cavity drives a lead screw and nut pair inside the cavity via a magnetohydrodynamic sealed transmission shaft, converting rotation into linear translation of the electrode plate. When using a piezoelectric-driven flexible platform, a piezoelectric ceramic stack drives a flexible hinge to generate micro-displacement, directly causing the electrode plate to translate or rotate about an axis perpendicular to the plate surface.

[0085] The planar adjustment actuator receives translation or rotation angle commands from the controller, causing the electrode plate it acts on to produce corresponding displacement or rotation within the plane of the plate surface. The planar adjustment actuator and the aforementioned electrically controlled displacement drive are independent of each other; the former produces displacement within the plate surface, while the latter produces displacement perpendicular to the plate surface. Their directions of movement are orthogonal and do not interfere with each other.

[0086] In one implementation, Aov is adjusted by translating the first electrode plate relative to the second electrode plate along the plate surface. The translation amount is denoted as Δx. When the through holes on the two electrode plates are arranged in the same square array and the hole diameter is the same φ, the overlapping area can be approximately calculated as Aov = s0 × (1 - Δx ÷ φ) within the range of 0 ≤ Δx ≤ φ, where s0 is the area of ​​a single through hole. When Δx is 0, the through holes on both sides are perfectly aligned, and Aov equals s0, reaching its maximum value; when Δx reaches φ, the through holes on both sides are completely offset, and Aov decreases to 0, reaching its minimum value.

[0087] It should be noted that the above correspondence only holds true within the interval 0 ≤ Δx ≤ φ. Since the vias are arranged in a periodic p array, when Δx continues to increase and exceeds φ, the via on the first electrode plate will gradually align with the next adjacent via on the second electrode plate. Aov will then repeat periodically p, increasing back to s0 when Δx approaches p. Therefore, the controller limits Δx to the interval 0 to φ when generating translation commands to avoid an unexpected increase in the overlap area.

[0088] In actual control, the controller first determines the target overlap area to be achieved based on the current conductivity margin and fluid resistance. Then, it solves for the required translation amount using Δx = φ × (1 - Aov ÷ s0), where Aov is substituted into the target overlap area. The Δx obtained from the inverse solution is limited to the range of 0 to φ and then sent as a displacement command to the planar adjustment actuator.

[0089] Following the example above, when the aperture φ is 2 mm, s0 = 3.14 mm². If we take Δx = 0.5 mm, then Aov = 3.14 × (1 - 0.5 ÷ 2) = 2.36 mm².

[0090] In another implementation, Aov is adjusted by rotating the first electrode plate relative to the second electrode plate about an axis perpendicular to the plate surface. The rotation angle is denoted as θ, in radians, and the equivalent translation of the monitoring area located at a distance Lr from the rotation center is calculated as Δx = Lr × θ. When using the rotation method, the equivalent translation at different positions on the plate surface increases with increasing Lr, thus allowing different overlapping areas to be obtained in different regions of the plate surface in a single adjustment. This is suitable for scenarios where the fluid resistance exhibits a gradient distribution along the plate surface.

[0091] Furthermore, after driving the first electrode plate or the second electrode plate to translate or rotate within its own surface, the method further includes: Reacquire the local resistance and local flow velocity for each monitoring area; For monitoring areas where both the change in local resistance and the change in local flow velocity are less than or equal to a set change, the distance between the two electrode plates in the monitoring area remains unchanged, and the driving device corresponding to the monitoring area is not controlled. For a monitoring area where at least one of the changes in local resistance and the changes in local flow velocity is greater than the set change, the driving component corresponding to the monitoring area is controlled to drive the corresponding adjusting component to move the electrode plate, so that the distance between the two electrode plates in the monitoring area reaches the target distance of the monitoring area.

[0092] Specifically, the change is denoted as εc, which is a pre-defined dimensionless constant. After translation or rotation, the controller re-acquires the local resistance Ri and local flow velocity vi of each monitoring area, and recalculates the changes in both according to ΔRi = |Ri1 - Ri0|÷ Ri0 and Δvi = |vi1 - vi0| ÷ vi0, where Ri1 and vi1 are the values ​​obtained from this re-acquisition, and Ri0 and vi0 are their respective reference values.

[0093] The reason for setting up this re-inspection step is that translation or rotation changes the relative position of the through holes on the two electrode plates, which in turn changes the shape of the airflow channel and the distribution of the discharge area. The local operating conditions of some monitoring areas may have thus returned to within acceptable limits. For such monitoring areas, changing the electrode spacing as originally planned would introduce new deviations. Therefore, for monitoring areas where ΔRi ≤ εc and Δvi ≤ εc, it is determined that the local operating conditions have been restored. The spacing between the two electrode plates in this monitoring area remains unchanged, and no displacement command is issued to the corresponding drive component, keeping the electrode spacing in this area at its state before translation or rotation. For monitoring areas where ΔRi > εc or Δvi > εc, it is determined that the local operating conditions have not yet been restored. The drive component corresponding to this monitoring area continues to drive the corresponding adjustment component to move the electrode plates, so that the spacing in this monitoring area reaches its target spacing Di.

[0094] In one implementation, the number of consecutive adjustments performed on the same monitoring area is denoted as Ci. Each adjustment is incremented by one. Ci is reset to zero when both ΔRi and Δvi of the monitoring area are less than or equal to εc. When Ci reaches a preset upper limit Cmax, but the monitoring area still does not satisfy ΔRi ≤ εc and Δvi ≤ εc, further adjustment of the monitoring area is stopped and an anomaly is reported to avoid plate skew caused by repeated adjustments due to local defects.

[0095] When the target spacing between two adjacent monitoring areas is exceeded, the average value of the change is calculated as Δd' = (Δdi + Δd(i+1)) ÷ 2 to make the displacement transition at the boundary smooth.

[0096] In another implementation, the change in target spacing of each monitoring area is smoothed according to its position on the board. That is, for the i-th monitoring area, the weighted average of its own and the changes of the adjacent monitoring areas is taken as the actual change amount. The weight decreases as the distance increases.

[0097] Using the above method, each monitoring area is driven independently according to its target spacing. Areas with large drift receive a corresponding adjustment, while areas without drift remain unchanged, avoiding the inconsistency of overall adjustment. The target spacing is determined by the difference in the area ratio of the through holes on the two plates, which can be calculated from the hole diameter and hole spacing, transforming spacing adjustment from relying on experience to quantitative calculation. The two-level judgment of overall threshold and local threshold takes into account both the timeliness and specificity of adjustment. The overlapping area between the through holes of the two electrode plates constitutes a second degree of freedom of adjustment independent of the electrode spacing, which is achieved by translation or rotation within the plate surface without changing the spacing between the plates and thus not disrupting the established electric field distribution. Based on this, a trade-off can be made between the uniformity of airflow distribution and the discharge capacity as needed. After translation or rotation, the local quantities of each area are re-acquired, and the spacing is changed only for the unrecovered areas, while the spacing remains unchanged for the recovered areas, limiting the spacing adjustment to the necessary range. The adjustment component that bears the displacement is selected from the side with a smaller through hole area ratio, i.e., higher stiffness, to avoid warping when pushing the side with lower stiffness. The aforementioned judgment and drive are automatically completed by the controller based on real-time collected operating voltage, inter-plate resistance, gas flow rate, and gas pressure. It can be adjusted online without breaking the vacuum chamber, and counts the number of consecutive adjustments in the same area; if the limit is exceeded, it stops and reports the anomaly. As a result, the electric field distribution along the plate surface is more uniform, the risk of glow discharge turning into arc light is suppressed, the processing effect of the same batch of workpieces tends to be consistent, the plasma impedance remains stable, radio frequency matching is maintained, and reflected power decreases.

[0098] Furthermore, this embodiment also proposes a parallel plate-type open electrode spacing adaptive adjustment system. This system is based on the same inventive concept as the aforementioned method embodiment, and its specific processing procedure can be referred to the description of the aforementioned method embodiment, which will not be repeated here.

[0099] like Figure 3 As shown, the system includes an adjustment component 301, a parameter acquisition component 302, and a controller 303.

[0100] The adjustment assembly 301 includes multiple adjustment elements and multiple driving elements corresponding to each of the multiple adjustment elements; the surfaces of the two electrode plates are divided into multiple monitoring areas, and each monitoring area corresponds to at least one adjustment element driven individually by the corresponding driving element. The parameter acquisition component 302 includes a voltage detection element, a resistance detection element, a flow rate detection element, and a pressure detection element, which are used to acquire the working voltage of the open electrode, the resistance between the two electrode plates, and the flow rate and pressure of the fluid flowing through the through hole, respectively. Controller 303, connected to the parameter acquisition component and each of the driving components, is used for: When the change in at least one of the operating voltage, the resistance, the flow rate and the pressure relative to the reference value exceeds the corresponding threshold, the percentage of the through-hole area of ​​the first electrode plate, the percentage of the through-hole area of ​​the second electrode plate and the current spacing between the two electrode plates are obtained in each monitoring area. For each monitoring area, the target spacing of the monitoring area is determined based on the difference in the area ratio of the two through holes in the monitoring area, and the moving direction and moving distance of the corresponding adjusting component are determined based on the target spacing and the current spacing. The driving components are controlled to drive the corresponding adjusting components to move the electrode plates, so that the distance between the two electrode plates in each monitoring area reaches the corresponding target distance.

[0101] It should be noted that the components described above can be connected via wired connections, or via fieldbus or industrial Ethernet, etc., and this application does not limit this. The specific calculation methods and judgment logic for each quantity in this embodiment are consistent with the aforementioned method embodiments, and will not be repeated here.

[0102] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for adaptive adjustment of the spacing between parallel flat-plate perforated electrodes, wherein the perforated electrodes include a first electrode plate and a second electrode plate disposed opposite to each other, and both electrode plates are provided with multiple through holes, characterized in that... include: The surfaces of the two electrode plates are divided into multiple monitoring areas, and each monitoring area corresponds to at least one adjustment element driven by a driving element alone. The operating voltage of the perforated electrode, the resistance between the two electrode plates, and the flow rate and pressure of the fluid flowing through the through hole are obtained. When the change of at least one of the operating voltage, the resistance, the flow rate and the pressure relative to the reference value exceeds the corresponding threshold, the percentage of the through-hole area of ​​the first electrode plate, the percentage of the through-hole area of ​​the second electrode plate and the current distance between the two electrode plates are obtained in each monitoring area. For each monitoring area, the target spacing of the monitoring area is determined based on the difference in the area ratio of the two through holes in the monitoring area, and the moving direction and moving distance of the corresponding adjustment component are determined based on the target spacing and the current spacing. The driving components are controlled to drive the corresponding adjusting components to move the electrode plates, so that the distance between the two electrode plates in each monitoring area reaches the corresponding target distance.

2. The method according to claim 1, characterized in that, The method further includes: The resistance between the first electrode plate and the second electrode plate in each monitoring area is obtained as the local resistance of that monitoring area; The flow velocity of the fluid after passing through the through-hole in each monitoring area is obtained as the local flow velocity of that monitoring area.

3. The method according to claim 2, characterized in that, The corresponding thresholds include overall thresholds and local thresholds; When the change in at least one of the operating voltage, the resistance, the flow rate and the pressure relative to the reference value exceeds the overall threshold, the target spacing is determined for all monitoring areas and the corresponding drive unit is controlled. When the change in local resistance in any monitoring area exceeds the local threshold, or the change in local flow velocity in the monitoring area exceeds the local threshold, the target spacing is determined only for that monitoring area and the corresponding drive unit is controlled.

4. The method according to claim 1, characterized in that, The step of obtaining the percentage of the through-hole area of ​​the first electrode plate and the percentage of the through-hole area of ​​the second electrode plate within each monitoring area includes: For each monitoring area, obtain the aperture of the through holes within that monitoring area and the hole spacing between adjacent through holes; The sum of the areas of the through holes per unit area within the monitoring area is determined based on the aperture and the hole spacing, and the ratio of the sum of the areas to the unit area is determined as the proportion of the through hole area of ​​the corresponding electrode plate within the monitoring area.

5. The method according to claim 4, characterized in that, Determining the target spacing of the monitoring area based on the difference in the area ratio of the two through holes within the monitoring area includes: The larger of the percentage of the through-hole area of ​​the first electrode plate and the percentage of the through-hole area of ​​the second electrode plate within the monitoring area is determined as the opening characteristic value of the monitoring area. The target spacing of the monitoring area is determined based on the opening feature value and the difference. The target spacing decreases as the opening feature value increases and decreases as the absolute value of the difference increases.

6. The method according to claim 5, characterized in that, The corresponding adjusting component is an adjusting component that bears displacement, and is determined as follows: When the proportion of the through-hole area of ​​the first electrode plate in the monitoring area is greater than that of the through-hole area of ​​the second electrode plate, the corresponding adjusting component is an adjusting component acting on the second electrode plate. When the proportion of the through-hole area of ​​the first electrode plate in the monitoring area is less than that of the through-hole area of ​​the second electrode plate, the corresponding adjusting component is an adjusting component acting on the first electrode plate. When the proportion of the through-hole area of ​​the first electrode plate is equal to the proportion of the through-hole area of ​​the second electrode plate, the corresponding adjusting member is an adjusting member that acts on both the first electrode plate and the second electrode plate simultaneously.

7. The method according to claim 1, characterized in that, Each monitoring area corresponds to at least two adjustment elements, one of which acts on the first electrode plate and the other of which acts on the second electrode plate; The driving component is an electrically controlled displacement driving component, and each driving component drives one of the adjusting components individually; under the drive of its corresponding driving component, the adjusting component drives the electrode plate it acts on to move in a direction perpendicular to the plate surface.

8. The method according to claim 2, characterized in that, Before controlling each of the aforementioned driving components to drive the corresponding adjusting components to move the electrode plate, the method further includes: When the flow rate is less than the set flow rate and the pressure is greater than the set pressure, the fluid resistance is determined to be too high; when the flow rate is greater than or equal to the set flow rate, or the pressure is less than or equal to the set pressure, the fluid resistance is determined to be normal. When the resistance is less than the set resistance, the conductivity is determined to be sufficient; when the resistance is greater than or equal to the set resistance, the conductivity is determined to be insufficient. When the fluid resistance is high and the conductivity is sufficient, the first electrode plate or the second electrode plate is driven to translate or rotate within its own plate surface, thereby increasing the overlap area between the through holes of the first electrode plate and the through holes of the second electrode plate. When the fluid resistance is normal and the conductivity is insufficient, the first electrode plate or the second electrode plate is driven to translate or rotate within its own plate surface, thereby reducing the overlapping area.

9. The method according to claim 8, characterized in that, After driving the first electrode plate or the second electrode plate to translate or rotate within its own surface, the method further includes: Reacquire the local resistance and local flow velocity for each monitoring area; For monitoring areas where both the change in local resistance and the change in local flow velocity are less than or equal to a set change, the distance between the two electrode plates in the monitoring area remains unchanged, and the driving device corresponding to the monitoring area is not controlled. For a monitoring area where at least one of the changes in local resistance and the changes in local flow velocity is greater than the set change, the driving component corresponding to the monitoring area is controlled to drive the corresponding adjusting component to move the electrode plate, so that the distance between the two electrode plates in the monitoring area reaches the target distance of the monitoring area.

10. A parallel flat plate type open electrode spacing adaptive adjustment system, wherein the open electrode includes a first electrode plate and a second electrode plate arranged opposite to each other, and both electrode plates are provided with multiple through holes, characterized in that, include: The adjustment assembly includes multiple adjustment elements and multiple drive elements corresponding one-to-one with the multiple adjustment elements; The surfaces of the two electrode plates are divided into multiple monitoring areas, and each monitoring area corresponds to at least one adjustment element that is individually driven by the corresponding driving element. The parameter acquisition component includes a voltage detection device, a resistance detection device, a flow rate detection device, and a pressure detection device, which are used to acquire the working voltage of the open electrode, the resistance between the two electrode plates, and the flow rate and pressure of the fluid flowing through the through hole, respectively. The controller, connected to the parameter acquisition component and each of the driving components, is used for: When the change in at least one of the operating voltage, the resistance, the flow rate and the pressure relative to the reference value exceeds the corresponding threshold, the percentage of the through-hole area of ​​the first electrode plate, the percentage of the through-hole area of ​​the second electrode plate and the current spacing between the two electrode plates are obtained in each monitoring area. For each monitoring area, the target spacing of the monitoring area is determined based on the difference in the area ratio of the two through holes in the monitoring area, and the moving direction and moving distance of the corresponding adjusting component are determined based on the target spacing and the current spacing. The driving components are controlled to drive the corresponding adjusting components to move the electrode plates, so that the distance between the two electrode plates in each monitoring area reaches the corresponding target distance.

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