A surface shape correction method for a sample

Abstract

The application discloses a sample surface correction method and relates to the technical field of semiconductor material surface correction. The sample surface correction method converts the sample from a horizontal state into a vertical state and faces the calibration probe through the swing movement system of the displacement table. The three-dimensional movement system of the displacement table drives the sample to move in the three-dimensional space, so that the calibration probe detects the edge of the sample, obtains the actual geometric center coordinates of the sample and the angle deviation around the Z axis and / or the X axis, and accurate positioning is realized. The coordinate offset value is calculated according to the actual geometric center coordinates and the theoretical geometric center coordinates, the angle compensation value is calculated according to the angle deviation, the initial workpiece coordinate system is subjected to the rotation matrix transformation or the angle compensation, the current workpiece coordinate system is completely matched with the actual physical posture of the sample, and then the calibration result is used to adjust the machining path and the scanning posture of the beam generating device, and finally, the deterministic scanning machining is performed in the current workpiece coordinate system which has completed the calibration and compensation.

Description

Technical Field

[0001] This invention relates to the field of semiconductor material surface correction technology, and more particularly to a method for correcting the surface of a sample. Background Technology

[0002] In the fields of semiconductor manufacturing and advanced optics, the surface accuracy of substrate materials such as wafers, fused silica, silicon carbide (SiC), sapphire, and calcium fluoride is a core factor determining the performance and yield of semiconductor devices, and directly affects the stability of subsequent processes and the quality of the final product.

[0003] In the surface correction process of the aforementioned materials, origin calibration is a crucial preliminary step that determines the final correction accuracy. Its core task is to accurately determine the geometric center, orientation angle, and spatial position of the sample to be processed (wafer, optical glass, etc.) before surface correction, establishing a unified processing benchmark for subsequent deterministic removal processes such as ion beam shaping and superatom beam shaping. The accuracy of origin calibration directly determines the accuracy of the material removal distribution, thus affecting the final surface convergence effect.

[0004] Existing technologies mostly employ simple mechanical centering or single-axis manual calibration methods. Operators independently align the sample in the X and Y directions, with each calibration process occurring in a fragmented manner. This step-by-step calibration method is not only inefficient but also struggles to ensure the consistency of the spatial positional relationship between the motion axes with the preset reference. Existing origin calibration methods typically achieve a sample positional accuracy of only ±0.01 mm after calibration. However, the processing trajectory planning for removal processes such as ion beams and superatom beams requires reference accuracy at the micrometer or even submicrometer level. Furthermore, even minute deviations in the sample's orientation can directly lead to material removal position shifts, making it difficult to further improve the accuracy after surface correction. Summary of the Invention

[0005] The purpose of this invention is to provide a method for correcting the surface shape of a sample, so as to perform multi-degree-of-freedom collaborative calibration on the processed surface of the sample, improve the calibration accuracy, and achieve angle compensation, so as to meet the stringent requirements of ultra-high precision sample surface shape correction on the processing reference.

[0006] To achieve this objective, the present invention adopts the following technical solution: A method for correcting the surface shape of a sample includes the following steps: The sample is fixed on the bearing surface of the sample positioning fixture, and the sample positioning fixture is driven to rotate by the swing motion system of the displacement stage, so that the sample changes from a horizontal state to a vertical state and faces the calibration probe. The sample is driven to move by the three-dimensional motion system of the displacement stage, so that the calibration probe performs edge detection on the sample to obtain the actual geometric center coordinates of the sample, as well as the angular deviation around the Z-axis and / or around the X-axis. The coordinate offset value is calculated based on the actual geometric center coordinates and the theoretical geometric center coordinates, and the angle compensation value is calculated based on the angle deviation. Perform rotation matrix transformation or angle compensation on the initial workpiece coordinate system to make the established current workpiece coordinate system completely match the actual physical posture of the sample; Based on the current workpiece coordinate system and the angle compensation value, adjust the processing path and scanning posture of the beam generator so that the scanning trajectory of the beam generator fits the processing surface of the sample. In the current workpiece coordinate system that has been calibrated and compensated, the beam generator is controlled to perform scanning processing according to the set path and attitude to complete the surface correction.

[0007] As an optional method for correcting the surface shape of the sample, the step of driving the sample to move through the three-dimensional motion system of the displacement stage, enabling the calibration probe to perform edge detection on the sample, and obtaining the actual geometric center coordinates of the sample, as well as the angular deviation around the Z-axis and / or around the X-axis, includes: The estimated center of the sample is moved to the detection range of the calibration probe by the three-dimensional motion system of the displacement stage, and the initial height of the sample on the Z-axis and the initial tilt angle around the X-axis are initially detected. The sample is driven to move by the rotation motion system of the displacement stage, the swing motion system and the three-dimensional motion system in a coordinated manner, and the edge and center area of ​​the processing surface of the sample are sampled at multiple points in the whole domain to obtain multiple position coordinates. Based on the collected multiple location coordinates, the actual geometric center coordinates, the rotation angle deviation Δθ around the Z-axis, and the tilt angle deviation Δα around the X-axis are calculated using a geometric algorithm.

[0008] As an optional method for correcting the surface shape of the sample, the specific steps of using the rotation motion system of the displacement stage, the swing motion system, and the three-dimensional motion system to collaboratively drive the sample motion, and to perform global multi-point sampling of the edge and central region of the processed surface of the sample to obtain multiple position coordinates include: The sample is driven to pass through the detection area of ​​the calibration probe in sequence along its left and right edges, so that the calibration probe continuously acquires the coordinates of the left and right edges in the X and Z axes. The sample is driven to pass through the detection area of ​​the calibration probe in sequence along its upper and lower edges, so that the calibration probe continuously acquires multiple position coordinates of the upper and lower edges in the Y and Z axis directions; The sample is driven to move its geometric center position below the calibration probe, and the calibration probe detects and records the actual Z-axis height of the geometric center position.

[0009] As an optional method for correcting the surface shape of the sample, a method for calculating the actual geometric center coordinates using a geometric algorithm based on multiple acquired position coordinates includes: The discrete X-axis and Z-axis coordinate data of the collected left and right edges are fitted into two independent ideal spatial straight lines; The discrete Y-axis and Z-axis coordinate data of the collected upper and lower edges are fitted into two independent ideal spatial straight lines; The midpoint coordinates of the two independent ideal spatial lines obtained from the fitting left and right edges in the X-axis direction are calculated and used as the horizontal center coordinates X of the sample. c ; The midpoint coordinates of the two independent ideal spatial lines obtained from the fitted upper and lower edges in the Y-axis direction are calculated and used as the vertical center coordinates Y of the sample. c ; Based on the actual Z-axis height at the geometric center location, determine the coordinates of the Z-axis origin Z. c The geometric center coordinates (X, X) of the sample are obtained. c ,Y c Z c ).

[0010] As an alternative method for correcting the surface shape of the sample, the method of calculating the rotation angle deviation Δθ around the Z-axis by means of a geometric algorithm includes: calculating the slope of the line connecting the upper and lower edges relative to the Y-axis, wherein Δθ reflects the deflection angle of the sample in the XY plane.

[0011] As an alternative method for correcting the surface shape of the sample, the method for calculating the tilt angle deviation Δα around the X-axis based on a geometric algorithm includes: The Δα is calculated by taking the ratio of the height difference between the upper and lower edges along the Z-axis to the distance between the Y-axis, and thus reflecting the tilt angle of the sample in the YZ plane.

[0012] As an optional method for correcting the surface shape of the sample, before calculating the actual geometric center coordinates, the rotation angle deviation Δθ around the Z-axis and the tilt angle deviation Δα around the X-axis using a geometric algorithm, the method further includes: preprocessing the collected multiple position coordinates to remove abnormal sampling points.

[0013] As an optional method for surface correction of the sample, the method for initially detecting the initial height of the sample on the Z-axis and the initial tilt angle around the X-axis includes: using the calibration probe to perform touch measurements at multiple preset points on the machined surface of the sample, obtaining Z-axis height data and calculating the tilt angle.

[0014] As an optional method for correcting the surface shape of the sample, in the step of performing a rotation matrix transformation or angle compensation on the initial workpiece coordinate system, the rotation matrix transformation is based on the calculated rotation angle deviation Δθ around the Z-axis and tilt angle deviation Δα around the X-axis, transforming the initial workpiece coordinate system through a rotation matrix R=R X (Δα)×R Z (Δθ) is transformed to the current workpiece coordinate system that coincides with the actual posture of the sample.

[0015] As an optional method for correcting the surface shape of the sample, when adjusting the processing path and scanning posture of the beam generator, the method further includes dynamically correcting the incident angle of the beam emitted by the beam generator according to the angle compensation value, so that the beam always acts on the processing surface of the sample in the normal or at a preset angle in the non-planar region.

[0016] As an optional method for surface correction of the sample, the specific method for controlling the beam generator to perform scanning processing according to a set path and attitude in the current workpiece coordinate system that has been calibrated and compensated to complete the surface correction includes: The surface correction program is invoked. Based on the preliminary measurement data of the sample's processing surface, and in the current workpiece coordinate system that has been calibrated and compensated, the dwell time, removal function parameters, and beam scanning attitude at each position are automatically adjusted. The beam generator is then controlled to perform scanning processing according to the set path and attitude to complete the surface correction.

[0017] The beneficial effects of this invention are: The sample surface correction method provided by this invention uses the swing motion system of a displacement stage to convert the sample from a horizontal state to a vertical state and align it with the calibration probe. The three-dimensional motion system of the displacement stage drives the sample to move in three-dimensional space, enabling the calibration probe to perform edge detection on the sample, obtain the actual geometric center coordinates and the angular deviations around the Z-axis and / or X-axis, realizing precise five-dimensional spatial attitude positioning from traditional two-dimensional spatial center positioning. The coordinate offset value is calculated based on the actual geometric center coordinates and the theoretical geometric center coordinates, and the angle compensation value is calculated based on the angular deviation. A rotation matrix transformation or angle compensation is performed on the initial workpiece coordinate system to ensure that the current workpiece coordinate system is completely matched with the actual physical posture of the sample. The calibration results are then directly used to adjust the processing path and scanning posture of the beam generator to ensure that the beam scanning trajectory accurately fits the sample processing surface. Finally, deterministic scanning processing is performed in the current workpiece coordinate system after calibration and compensation. The surface correction method of this sample improves the positional accuracy after calibration to over ±0.01mm and achieves arcsecond-level angle compensation, providing a high-precision benchmark for the surface correction of ultra-high precision semiconductor material samples and improving the quality of sample surface correction. Attached Figure Description

[0018] Figure 1 This is a flowchart of the sample surface correction method provided in the embodiments of the present invention; Figure 2 This is a schematic diagram of the displacement stage and sample positioning fixture provided in an embodiment of the present invention; Figure 3 This is a schematic diagram illustrating the state of the calibration probe contacting the sample surface to obtain the current spatial coordinate value, provided in an embodiment of the present invention. Figure 4 This is a flowchart of a method for obtaining the actual geometric center coordinates of a sample, and the angular deviation around the Z-axis and / or around the X-axis, provided in an embodiment of the present invention. Figure 5 This is a schematic diagram illustrating the principle of calculating the rotation angle deviation Δθ around the Z-axis provided in an embodiment of the present invention; Figure 6 This is a schematic diagram illustrating the principle of calculating the tilt angle deviation Δα around the X-axis provided in an embodiment of the present invention.

[0019] In the picture: 100. Sample; 1. Sample positioning fixture; 2. Zero-point positioning system; 3. Rotation motion system; 4. Swinging motion system; 5. X-axis drive assembly; 6. Y-axis drive assembly; 7. Z-axis drive assembly; 8. Calibration probe. Detailed Implementation

[0020] Embodiments of the present invention are described in detail below. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0021] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The terms "first position" and "second position" refer to two different positions.

[0022] Unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to fixed connections or detachable connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and connections within two components or interactions between two components. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0023] Unless otherwise expressly specified and limited, "above" or "below" a second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of a second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" of a second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0024] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0025] like Figure 1 As shown, this embodiment provides a method for correcting the surface shape of a sample, including the following steps: S10. Fix the sample 100 on the bearing surface of the sample positioning fixture 1, and drive the sample positioning fixture 1 to rotate through the swing motion system 4 of the displacement stage, so that the sample 100 changes from a horizontal state to a vertical state and faces the calibration probe 8.

[0026] Sample 100 can be a substrate material or optical element such as wafer, fused silica, silicon carbide (SiC), sapphire and calcium fluoride.

[0027] like Figure 2 and Figure 3 As shown, the sample positioning fixture 1 has a bearing surface, on which positioning elements adapted to the shape and structure of the sample 100 are provided, providing a unified positioning reference for the sample 100. The sample 100 is fixedly connected to the bearing surface by means of vacuum adsorption, snap-fit, clamping or bonding to ensure the stability of the sample 100's position during subsequent clamping and correction processes.

[0028] The sample positioning fixture 1 is detachably connected to the zero-point positioning system 2. The zero-point positioning system 2 is a finished product used to achieve rapid and accurate clamping of the sample positioning fixture 1. Its repeatability is controlled within 0.005mm, thereby ensuring the consistency of the position of the sample 100 after clamping and reducing the impact of clamping error on the correction accuracy.

[0029] The displacement stage includes a rotation motion system 3, a swing motion system 4, and a three-dimensional motion system. The rotation motion system 3 is connected to the zero-point positioning system 2 and is used to drive the zero-point positioning system 2 to rotate. The swing motion system 4 is connected to the rotation motion system 3 and is used to drive the rotation motion system 3 to swing. The three-dimensional motion system includes an X-axis drive assembly 5, a Y-axis drive assembly 6, and a Z-axis drive assembly 7. The Y-axis drive assembly 6 is connected to the swing motion system 4 and is used to drive the swing motion system 4 to move along the Y-axis direction. The X-axis drive assembly 5 is connected to the Y-axis drive assembly 6 and is used to drive the Y-axis drive assembly 6 to move along the X-axis direction. The Z-axis drive assembly 7 is connected to the X-axis drive assembly 5 and is used to drive the X-axis drive assembly 5 to move along the Z-axis direction.

[0030] Specifically, both the rotation system 3 and the swing motion system 4 are driven by torque motors and equipped with grating rulers. The torque motors drive the rotating shaft without the need for intermediate transmission components such as reducers, eliminating the inherent backlash error of transmission mechanisms such as gears and worm gears, and avoiding the backlash and motion lag caused by them. At the same time, together with the grating rulers, a fully closed-loop angle feedback is formed, which can read the actual position of the rotating shaft in real time and compare and correct it with the target command, thereby achieving high-precision angle positioning and repeatability.

[0031] The X-axis drive assembly 5, Y-axis drive assembly 6, and Z-axis drive assembly 7 all employ a servo motor to drive the ball screw rotation. The ball screw drives the driven component to move along the linear slide rail through the nut seat. Furthermore, a grating ruler is provided to detect the linear displacement in real time, thereby achieving closed-loop control.

[0032] When installing sample 100, the bearing surface of sample positioning fixture 1 is perpendicular to the Y-axis and is in a horizontal state to facilitate the installation of sample 100. After sample 100 is installed, the swing motion system 4 drives the rotation motion system 3 to rotate sample positioning fixture 1 by 90 degrees, so that the bearing surface of sample positioning fixture 1 is perpendicular to the Z-axis and faces the calibration probe 8.

[0033] The displacement stage and calibration probe 8 are both electrically connected to the control system. The control system controls the displacement stage to drive the sample positioning fixture 1 to move so that different positions of the sample 100 contact the calibration probe 8, and receives the feedback signal from the calibration probe 8 to obtain multiple position coordinates of the sample 100.

[0034] The calibration probe 8 is a micro-motion sensor of the coordinate measuring machine. When the micro-motion sensor comes into contact with the processing surface of the sample 100, it will generate a trigger signal. The control system receives the trigger signal and records the current position coordinates.

[0035] S20. The sample 100 is driven to move by the three-dimensional motion system of the displacement stage, so that the calibration probe 8 performs edge detection on the sample 100, obtains the actual geometric center coordinates of the sample 100, and the angular deviation around the Z-axis and / or around the X-axis.

[0036] Specifically, the calibration probe 8 is positioned at the beam position of the beam generator to align the geometric center of the sample 100 with the beam center of the beam generator.

[0037] In one embodiment, such as Figure 4 As shown, step S20 specifically includes: S21. The estimated center of sample 100 is moved to the detection range of calibration probe 8 through the three-dimensional motion system of the displacement stage, and the initial height of sample 100 on the Z-axis and the initial tilt angle around the X-axis are initially detected.

[0038] The method for obtaining the estimated center of sample 100 is as follows: based on the theoretical design dimensions of sample 100 and the installation reference of sample positioning fixture 1, the theoretical geometric center coordinates (X0, Y0, Z0) of sample 100 in the displacement stage coordinate system are calculated in advance. These theoretical geometric center coordinates can be used as the initial position of the "estimated center".

[0039] The control system controls the three-dimensional motion system of the displacement stage to drive the sample positioning fixture 1 and sample 100 to move, so that the estimated center of sample 100 is moved into the detection area of ​​calibration probe 8. The detection area is usually defined as the effective working range of calibration probe 8.

[0040] In one embodiment, the method for initially detecting the initial height of the Z-axis and the initial tilt angle around the X-axis of the sample 100 includes: performing touch measurements at multiple preset points on the machined surface of the sample 100 using a calibration probe 8 to obtain Z-axis height data and calculate the tilt angle.

[0041] Specifically, near the estimated center of the machining surface of sample 100, at least one preset point is selected, such as directly selecting the estimated center point. The Z-axis drive assembly 7 drives sample 100 to move slowly along the Z-axis direction, so that the calibration probe 8 contacts the preset point on the machining surface. After the calibration probe 8 is triggered, the control system records the current Z-axis coordinate, which is denoted as Z1.

[0042] Furthermore, to improve the accuracy of the measurement, 3 to 5 points near the estimated center point can be selected to measure the Z-axis coordinates, and the average value can be taken as the initial height.

[0043] Since the tilt angle of sample 100 around the X-axis will cause a height difference in the Y-axis direction of the machined surface of sample 100, the initial tilt angle can be calculated by measuring the ratio of the height difference between the upper and lower edges of sample 100 on the Z-axis to the distance between the Y-axis.

[0044] The measured initial height of the Z-axis and the initial tilt angle around the X-axis are stored in the control system. Before subsequent global multi-point sampling, the control system can first perform pre-compensation on the initial workpiece coordinate system based on the initial tilt angle around the X-axis. For example, the sample 100 is driven by the swing motion system 4 to make it approximately horizontal, so as to ensure that the estimated center and surrounding area of ​​the sample 100 are within the safe detection stroke of the calibration probe 8. This reduces the collision or lateral force between the calibration probe 8 and the sample 100 during the sampling process, extends the service life of the calibration probe 8, and improves the safety of the measurement.

[0045] S22. The sample 100 is driven to move by the rotation motion system 3, the swing motion system 4 and the three-dimensional motion system of the displacement stage, and the edge and center area of ​​the processing surface of the sample 100 are sampled at multiple points to obtain multiple position coordinates.

[0046] The control system controls the displacement stage to drive the sample 100 to perform multi-axis linkage motion relative to the stationary calibration probe 8, so as to realize full-area multi-point sampling of the edge and center area of ​​the processing surface of the sample 100.

[0047] Specifically, it includes the following steps: S221, drive the sample 100 so that its left and right edges pass through the detection area of ​​the calibration probe 8 in sequence, so that the calibration probe 8 continuously acquires the coordinates of the left and right edges in the X and Z axes.

[0048] Based on the initial height Z1 of the Z-axis and the theoretical geometric center coordinates (X0, Y0, Z0) obtained from the preliminary detection, the estimated center of the sample 100 is moved directly below the calibration probe 8, and the machined surface of the sample 100 is kept at a safe distance from the calibration probe 8. For example, the safe distance is 0.5 mm.

[0049] During left edge sampling, the control stage drives sample 100 to move along the negative X-axis, gradually bringing the left edge of sample 100 closer to calibration probe 8. The movement speed is low, for example, 1mm / s to 5mm / s, to prevent collisions. When calibration probe 8 touches the left edge of sample 100, a trigger signal is sent to the control system. To obtain the contour information of the left edge, multiple samples can be taken at different Y-coordinate positions on the left edge. Specifically, after each contact, the stage drives sample 100 back to a safe position along the positive X-axis, then moves a preset step length along the Y-axis, and feeds again along the negative X-axis for the next contact. The coordinates (X, Y, Y) of all left edge sampling points are recorded. Li ,Y i Z Li ), where Y i This represents the position on the Y-axis at each touch.

[0050] When sampling the right edge, follow a similar method described above, moving along the positive X-axis until the right edge touches the calibration probe 8. Similarly, collect multiple sampling points at different Y-coordinate positions and record ((X... Rj ,Y j Z Rj ).

[0051] S222, drive the sample 100 so that its upper and lower edges pass through the detection area of ​​the calibration probe 8 in sequence, so that the calibration probe 8 continuously collects the coordinates of the upper and lower edges in the Y and Z axes.

[0052] Specifically, during upper edge sampling, the displacement stage drives the sample 100 to move along the positive Y-axis, causing the upper edge of the sample 100 to touch the calibration probe 8. The calibration probe 8 then sends a touch signal to the control system. Multiple samples are taken at different X-coordinate positions, and the coordinates of multiple sampling points (X...) are recorded. k ,Y Uk Z Uk During lower edge sampling, the sample 100 is driven to move along the negative Y-axis so that its lower edge touches the calibration probe 8, and the coordinates of multiple sampling points (X) are recorded. l ,Y Dl Z Dl ).

[0053] S223, drive sample 100 to move its geometric center position below calibration probe 8, and calibration probe 8 detects and records the actual Z-axis height of the geometric center position.

[0054] Based on the preliminary center coordinates (X) calculated by fitting in steps S221 and S222 C ,Y C The geometric center of sample 100 is precisely moved to be directly below the calibration probe 8 (X=X). C Y=Y C ).

[0055] The displacement stage drives the sample 100 to move slowly along the Z-axis until the calibration probe 8 touches the machined surface of the sample 100. The calibration probe 8 sends a trigger signal to the control system, and the control system records the current Z-axis coordinate. C .

[0056] The measurement can be repeated 3 times at the geometric center, and the average value is taken to reduce random error.

[0057] By acquiring multiple sampling points at different Y positions on the left and right edges and at different X positions on the top and bottom edges, it is possible to effectively capture any local unevenness or minor deformation that may exist on the edges of sample 100. Multi-point fitting can eliminate random errors caused by single-point measurements, improve the robustness of subsequent geometric center calculations, and achieve a repeatability accuracy better than ±0.005 mm.

[0058] By precisely establishing the Z-axis origin at the actual geometric center of the sample 100, deviations introduced by edge calculations are avoided, making it particularly suitable for large-size or thin-plate wafers or optical glass.

[0059] S23. Preprocess the collected coordinates of multiple locations and remove abnormal sampling points.

[0060] Because the surface of sample 100 may contain dirt or microscopic defects, and mechanical vibration may interfere with the measurement data, the collected data may contain outliers. If these outliers are not removed, they will directly affect the accuracy of subsequent line fitting, geometric center calculation, and angle deviation calculation.

[0061] Therefore, before calculating the actual geometric center and angular deviation, the control system preprocesses the collected coordinates of multiple locations to remove abnormal sampling points. The specific preprocessing methods are as follows: 1. Remove invalid data that significantly exceeds the design size range of sample 100. 2. Remove abnormal points caused by microscopic defects or mechanical vibration interference that differ excessively from adjacent sampling points.

[0062] After removing outlier sampling points, the fitted edge line can be made closer to the true ideal contour of sample 100, the accuracy of geometric center coordinates can be improved by an order of magnitude, and the angle deviation calculation error can be controlled within ±1 arcsecond.

[0063] S24. Based on the collected coordinates of multiple locations, calculate the actual geometric center coordinates, the rotation angle deviation Δθ around the Z-axis, and the tilt angle deviation Δα around the X-axis using a geometric algorithm.

[0064] Specifically, the method for calculating the actual geometric center coordinates based on multiple collected position coordinates using a geometric algorithm includes: fitting the discrete X-axis and Z-axis coordinate data of the collected left and right edges into two independent ideal spatial lines to represent the true geometric pose of the left and right edges of sample 100; fitting the discrete Y-axis and Z-axis coordinate data of the collected upper and lower edges into two independent ideal spatial lines to represent the true geometric pose of the upper and lower edges of sample 100; and calculating the midpoint coordinates of the two independent ideal spatial lines of the fitted left and right edges in the X-axis direction as the horizontal center coordinates X of sample 100. c Calculate the midpoint coordinates of the two independent ideal spatial lines obtained from the fitted upper and lower edges in the Y-axis direction, and use them as the vertical center coordinates Y of sample 100. c Based on the actual Z-axis height at the geometric center location, determine the coordinates of the Z-axis origin. c The geometric center coordinates (X, X) of sample 100 were obtained. c ,Y c Z c ).

[0065] like Figure 5 As shown, the method for calculating the rotation angle deviation Δθ around the Z-axis using a geometric algorithm includes: calculating the slope of the line connecting the upper and lower edges relative to the Y-axis, where Δθ reflects the deflection angle of sample 100 in the XY plane.

[0066] Assuming sample 100 is rectangular, its upper and lower edges should ideally be parallel to the X-axis. If sample 100 has an angular deviation Δθ around the Z-axis, the upper and lower edges will be misaligned in the X-direction. That is, the line connecting the upper and lower edges will no longer be parallel to the Y-axis, but will form an angle Δθ with it. The coordinates of the endpoints of the upper edge are (X1, Y1, Z1), and the coordinates of the endpoints of the lower edge are (X2, Y2, Z2). The slope of the line connecting the upper and lower edges relative to the Y-axis is k = (X1 - X2) / (Y1 - Y2). Therefore, the deflection angle Δθ satisfies: tan(Δθ) = k, and thus, Δθ = arctan(k).

[0067] like Figure 6 As shown, the method for calculating the tilt angle deviation Δα around the X-axis using a geometric algorithm includes: calculating the ratio of the height difference between the upper and lower edges on the Z-axis to the distance between the upper and lower edges on the Y-axis, and obtaining Δα as the tilt angle of sample 100 in the YZ plane. That is, tan(Δα) = ΔZ´ / ΔY´, where ΔZ´ = Z1 - Z2, ΔY´ = Y1 - Y2, and Δα = arctan(ΔZ´ / ΔY´).

[0068] S30. Calculate the coordinate offset value based on the actual geometric center coordinates and the theoretical geometric center coordinates, and calculate the angle compensation value based on the angle deviation.

[0069] After completing the preprocessing of the sampled data and the actual geometric center coordinates (X... c ,Y c Z c After calculating the rotation angle deviation Δθ around the Z-axis and the tilt angle deviation Δα around the X-axis, the control system compares these measured results with the theoretical design values ​​and calculates the offset and compensation values ​​used for subsequent coordinate system transformation and machining path correction.

[0070] The coordinate offset value is calculated as follows: ΔX = X0 - X c ; ΔY=Y0-Y c ΔZ = Z0 - Z c .

[0071] The angle compensation value is the negative of the angle deviation, that is, the angle compensation value is: Δθ 补偿 =-Δθ;Δα 补偿 =-Δα.

[0072] Let ΔX, ΔY, ΔZ, Δθ 补偿 and Δα 补偿 Stored in the bias register of the control system or the workpiece coordinate system offset table.

[0073] S40. Perform rotation matrix transformation or angle compensation on the initial workpiece coordinate system to make the established current workpiece coordinate system completely match the actual physical posture of sample 100.

[0074] Specifically, in the step of performing rotation matrix transformation or angle compensation on the initial workpiece coordinate system, the rotation matrix transformation is based on the calculated rotation angle deviation Δθ around the Z-axis and tilt angle deviation Δα around the X-axis, transforming the initial workpiece coordinate system through the rotation matrix R=R X (Δα)×R Z (Δθ) is transformed to the current workpiece coordinate system that coincides with the actual posture of sample 100.

[0075] S50. Based on the current workpiece coordinate system and angle compensation value after matching, adjust the processing path and scanning posture of the beam generator so that the scanning trajectory of the beam fits the processing surface of the sample 100.

[0076] Specifically, when adjusting the processing path and scanning posture of the beam generator, the method also includes dynamically correcting the incident angle of the ion beam or superatomic beam emitted by the beam generator according to the angle compensation value, so that the beam always acts on the surface of the sample 100 in the normal or preset angle in the non-planar region.

[0077] The current workpiece coordinate system and angle compensation value obtained during the calibration phase are applied to the generation and real-time control of the beam processing path, so that the scanning trajectory of the beam precisely fits the processing surface of the sample 100, and the incident angle of the beam is dynamically adjusted in the non-planar area to achieve material removal at the normal or preset angle.

[0078] The dynamic correction method for the incident angle of the beam is as follows: the oscillating motion system 4 and the rotation motion system 3 of the displacement stage adjust the attitude of the sample 100 in real time so that the normal of the current processing point on the processing surface of the sample 100 coincides with the beam direction.

[0079] In this embodiment, the beam generating device is an ion beam generating device or a superatomic beam generating device. The beam emitted by the ion beam generating device is an ion beam, and the beam emitted by the superatomic beam generating device is a superatomic beam. The ion beam and the superatomic beam can remove the processing surface of the sample to achieve a reference accuracy of micrometer or even submicrometer level.

[0080] S60. Under the current workpiece coordinate system that has been calibrated and compensated, control the beam generator to perform scanning processing according to the set path and attitude to complete the surface correction.

[0081] Specifically, the surface correction program is invoked. Based on the preliminary measurement data of the processed surface of the sample 100, under the current workpiece coordinate system that has been calibrated and compensated, the dwell time, removal function parameters and beam scanning attitude at each position are automatically adjusted, and the beam generator is controlled to perform scanning processing according to the set path and attitude to complete the surface correction.

[0082] After completing the calibration and compensation of the current workpiece coordinate system, the control system automatically triggers the start signal of the surface correction program. When the surface correction program is invoked, it automatically receives the calibrated and compensated current workpiece coordinate system and performs coordinate transformation based on the calibrated current workpiece coordinate system to align its origin with the actual geometric center of sample 100, and ensures that the direction of the current workpiece coordinate system is consistent with the actual orientation of sample 100. Methods for automatically adjusting the dwell time at each position, removing function parameters, and beam scanning orientation can be found in existing technologies; these are not the focus of this invention and will not be elaborated upon here.

[0083] The sample surface correction method provided in this embodiment uses the swing motion system 4 of the displacement stage to change the sample 100 from a horizontal state to a vertical state and align it with the calibration probe 8. The three-dimensional motion system of the displacement stage drives the sample 100 to move in three-dimensional space, enabling the calibration probe 8 to perform edge detection on the sample 100, obtain the actual geometric center coordinates and the angular deviations around the Z-axis and / or X-axis, realizing the transition from traditional two-dimensional spatial center positioning to precise five-dimensional spatial attitude positioning. The coordinate offset value is calculated based on the actual geometric center coordinates and the theoretical geometric center coordinates, and the angle compensation value is calculated based on the angular deviation. A rotation matrix transformation or angle compensation is performed on the initial workpiece coordinate system to ensure that the current workpiece coordinate system is completely matched with the actual physical attitude of the sample 100. The calibration results are then directly used to adjust the processing path and scanning attitude of the beam generator to ensure that the beam scanning trajectory accurately fits the processing surface of the sample 100. Finally, deterministic scanning processing is performed in the current workpiece coordinate system after calibration and compensation. The surface correction method of this sample improves the positional accuracy after calibration to over ±0.01mm and achieves arcsecond-level angle compensation, providing a high-precision benchmark for the surface correction of ultra-high precision semiconductor materials or optical components, and improving the quality of sample surface correction.

[0084] The above description is only a preferred embodiment of the present invention. For those skilled in the art, there will be changes in the specific implementation and application scope based on the ideas of the present invention. The content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for correcting the surface shape of a sample, characterized in that, Includes the following steps: The sample (100) is fixed on the bearing surface of the sample positioning fixture (1), and the sample positioning fixture (1) is driven to rotate by the swing motion system (4) of the displacement stage, so that the sample (100) changes from a horizontal state to a vertical state and faces the calibration probe (8). The sample (100) is driven to move by the three-dimensional motion system of the displacement stage, so that the calibration probe (8) performs edge detection on the sample (100) to obtain the actual geometric center coordinates of the sample (100) and the angular deviation around the Z-axis and / or around the X-axis. The coordinate offset value is calculated based on the actual geometric center coordinates and the theoretical geometric center coordinates, and the angle compensation value is calculated based on the angle deviation. Perform a rotation matrix transformation or angle compensation on the initial workpiece coordinate system to make the established current workpiece coordinate system completely match the actual physical posture of the sample (100); Based on the current workpiece coordinate system and the angle compensation value, adjust the processing path and scanning posture of the beam generator so that the scanning trajectory of the beam generator fits the processing surface of the sample (100). In the current workpiece coordinate system that has been calibrated and compensated, the beam generator is controlled to perform scanning processing according to the set path and attitude to complete the surface correction.

2. The sample surface correction method according to claim 1, characterized in that, The step of driving the sample (100) to move through the three-dimensional motion system of the displacement stage, so that the calibration probe (8) performs edge detection on the sample (100) to obtain the actual geometric center coordinates of the sample (100) and the angular deviation around the Z-axis and / or around the X-axis includes: The estimated center of the sample (100) is moved to the detection range of the calibration probe (8) through the three-dimensional motion system of the displacement stage, and the initial height of the sample (100) on the Z-axis and the initial tilt angle around the X-axis are initially detected. The sample (100) is driven to move by the rotation motion system (3), the swing motion system (4) and the three-dimensional motion system of the displacement stage, and the edge and center area of ​​the processing surface of the sample (100) are sampled at multiple points in the whole domain to obtain multiple position coordinates. Based on the collected multiple location coordinates, the actual geometric center coordinates, the rotation angle deviation Δθ around the Z-axis, and the tilt angle deviation Δα around the X-axis are calculated using a geometric algorithm.

3. The sample surface correction method according to claim 2, characterized in that, The specific steps for the sample (100) to be moved by the coordinated rotation motion system (3), the swing motion system (4) and the three-dimensional motion system of the displacement stage, and to obtain multiple position coordinates by sampling the edge and center area of ​​the processing surface of the sample (100) at multiple points, include: The sample (100) is driven to pass through the detection area of ​​the calibration probe (8) in sequence with its left and right edges, so that the calibration probe (8) continuously acquires multiple position coordinates of the left and right edges in the X and Z axis directions; The sample (100) is driven to pass through the detection area of ​​the calibration probe (8) in sequence, so that the calibration probe (8) continuously collects multiple position coordinates of the upper and lower edges in the Y-axis and Z-axis directions; The sample (100) is driven to move its geometric center position below the calibration probe (8), and the calibration probe (8) detects and records the actual Z-axis height of the geometric center position.

4. The sample surface correction method according to claim 3, characterized in that, The method for calculating the actual geometric center coordinates using a geometric algorithm based on multiple collected location coordinates includes: The discrete X-axis and Z-axis coordinate data of the collected left and right edges are fitted into two independent ideal spatial straight lines; The discrete Y-axis and Z-axis coordinate data of the collected upper and lower edges are fitted into two independent ideal spatial straight lines; The midpoint coordinates of the two independent ideal spatial lines obtained from the fitting left and right edges in the X-axis direction are calculated and used as the horizontal center coordinates X of the sample (100). c ; The midpoint coordinates of the two independent ideal spatial lines obtained from the fitted upper and lower edges in the Y-axis direction are calculated and used as the vertical center coordinates Y of the sample (100). c ; Based on the actual Z-axis height at the geometric center location, determine the coordinates of the Z-axis origin Z. c The geometric center coordinates (X) of the sample (100) are obtained. c ,Y c Z c ).

5. The sample surface correction method according to claim 3, characterized in that, Methods for calculating the rotation angle deviation Δθ around the Z-axis using geometric algorithms include: The slope of the line connecting the upper and lower edges relative to the Y-axis is calculated, and the Δθ reflects the deflection angle of the sample (100) in the XY plane.

6. The sample surface correction method according to claim 3, characterized in that, Methods for calculating the tilt angle deviation Δα around the X-axis using geometric algorithms include: The Δα is derived by calculating the ratio of the height difference between the upper and lower edges along the Z-axis to the distance between the Y-axis, and the angle of inclination of the sample (100) in the YZ plane.

7. The sample surface correction method according to claim 2, characterized in that, Before the steps of calculating the actual geometric center coordinates, the rotation angle deviation Δθ around the Z-axis, and the tilt angle deviation Δα around the X-axis using a geometric algorithm, the method further includes: preprocessing the collected multiple position coordinates to remove abnormal sampling points.

8. The sample surface correction method according to claim 2, characterized in that, The method for initially detecting the initial height of the Z-axis and the initial tilt angle around the X-axis of the sample (100) includes: using the calibration probe (8) to perform touch measurement at multiple preset points on the machining surface of the sample (100), obtaining Z-axis height data and calculating the tilt angle.

9. The sample surface correction method according to claim 1, characterized in that, In the step of performing rotation matrix transformation or angle compensation on the initial workpiece coordinate system, the rotation matrix transformation is based on the calculated rotation angle deviation Δθ around the Z-axis and tilt angle deviation Δα around the X-axis, transforming the initial workpiece coordinate system through the rotation matrix R=R X (Δα)×R Z (Δθ) is transformed to the current workpiece coordinate system that coincides with the actual posture of the sample (100).

10. The method for correcting the surface shape of a sample according to claim 1, characterized in that, When adjusting the processing path and scanning posture of the beam generator, the method further includes: dynamically correcting the incident angle of the beam emitted by the beam generator according to the angle compensation value, so that the beam always acts on the processing surface of the sample (100) in the non-planar region at the normal or preset angle.

11. The method for correcting the surface shape of a sample according to claim 1, characterized in that, The method for controlling the beam generator to perform scanning processing according to a set path and attitude to complete surface correction in the current workpiece coordinate system that has been calibrated and compensated includes: The surface correction program is invoked. Based on the preliminary measurement data of the processing surface of the sample (100), under the current workpiece coordinate system that has been calibrated and compensated, the dwell time, removal function parameters and beam scanning posture of each position are automatically adjusted, and the beam generating device is controlled to perform scanning processing according to the set path and posture to complete the surface correction.

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