A method for correcting the height runout error of a point scanning profilometer

Abstract

The present invention discloses a method for correcting the height-direction runout error of a point scanning profilometer, which solves the problems of the existing technology in the point scanning profilometer having the height-direction runout error and low measurement accuracy. The point scanning profilometer used in the error correction method of the present invention includes a base, a gantry column and a Y-direction direct-drive motion table are provided on the base, a vertical screw module is provided on the gantry column, and a vertical motion component is provided on the vertical screw module; the vertical motion component includes a turntable and a swing table connected to each other; a high-precision displacement sensor is provided on the swing table; an X-direction direct-drive motion table is provided on the Y-direction direct-drive motion table; and a marble adjustment platform is provided on the X-direction direct-drive motion table. The present invention utilizes the high-precision displacement sensor provided by the point scanning profilometer to effectively reduce the influence of the runout error of the X-direction and Y-direction direct-drive motion tables during movement on the measurement results of the sample height information; the non-contact measurement avoids the friction and wear between the probe and the sample while ensuring the measurement efficiency; and effectively ensures the accuracy of the sample profile measurement.

Description

Technical Field

[0001] The present invention relates to the technical field of profile detection, in particular to a method for correcting a height-direction runout error of a point scanning profiler. Background Art

[0002] Currently, the main methods for measuring sample surface topography include visual photography and contact probe scanning. Visual photography uses a photosensitive chip within a camera to image the sample, then uses image processing algorithms to calculate the dimensions of corresponding features or between features. Contact probe scanning uses a microprobe to continuously or intermittently contact the surface of the sample being measured, sensing and outputting height changes. Combined with the position information from planar motion, it can reconstruct the three-dimensional topography of the sample surface, thereby enabling surface topography measurement.

[0003] Visual photography methods struggle to capture height variations in sample surface topography and are generally used only for planar dimension detection. An example of this is the optical scanning 3D topography instrument described in Publication No. CN 212903082 U. Contact probe scanning methods require the probe to repeatedly contact the sample surface, which carries the risk of damaging the surface and increasing wear on the scanning probe. For example, Publication No. CN 110514138 A describes a topography measurement system and method based on the probe's own gravity.

[0004] Point scanning topography instruments use non-contact, high-precision displacement sensors, eliminating the friction and wear of contact probes. The high-precision displacement sensors acquire height point cloud data of the sample's surface topography. Combined with the planar point position information from a feedback-controlled planar motion stage, they can precisely reconstruct the sample's surface microstructure, thereby enabling three-dimensional topography detection of the sample's surface. For example, the free-form surface non-contact dimensionality reduction error separation detection method and device, published with publication number CN 108225213 A, does not guarantee accurate detection of the sample's surface topography. However, due to factors such as height runout error between the slider and the guide rail during motion, the height point cloud data acquired by the high-precision displacement sensor contains not only information about the sample's surface topography but also the height runout error of the planar motion stage during motion. This seriously interferes with the accuracy of the sample's surface topography detection. Summary of the Invention

[0005] In view of the deficiencies in the above-mentioned background technology, the present invention proposes a method for correcting the height-direction runout error of a point scanning profilometer, which solves the problems of height-direction runout error and low measurement accuracy of the point scanning profilometer in the prior art.

[0006] The technical solution of the present invention is achieved as follows: a point scanning profilometer includes a base, on which a gantry column and a Y-axis direct-drive motion stage are mounted, the gantry column is equipped with a vertical screw module, and the vertical screw module is equipped with a vertical motion assembly; the vertical motion assembly includes a rotating table and an oscillating table connected to each other; a high-precision displacement sensor is mounted on the oscillating table; an X-axis direct-drive motion stage is mounted on the Y-axis direct-drive motion stage; and an adjustment platform is mounted on the X-axis direct-drive motion stage for placing a sample under test. The vertical motion assembly and the adjustment platform are used to adjust the light emission angle of the high-precision displacement sensor relative to the sample under test. The Y-axis direct-drive motion stage and the X-axis direct-drive motion stage move in coordination so that the light spot emitted by the high-precision displacement sensor can perform an "S"-shaped point scanning motion at a certain interval on the surface of the sample under test. The high-precision displacement sensor provided in the point scanning profilometer effectively reduces the impact of runout error during the movement of the X-axis and Y-axis direct-drive motion stages on the sample height information measurement results. Non-contact measurement ensures measurement efficiency while avoiding friction and wear between the probe and the sample, effectively ensuring the accuracy of sample topography measurement.

[0007] A method for correcting height runout error of a point scanning profilometer is disclosed. The method employs the aforementioned point scanning profilometer and includes the following steps: S1: adjusting an adjustment platform to maintain a horizontal position; then adjusting the height of a high-precision displacement sensor so that the overall surface height variation of the adjustment platform is within the measurement range of the high-precision displacement sensor; and adjusting a rotary table and a swing table on a vertical motion assembly so that the height measurement result of the high-precision displacement sensor at a certain scanning point is minimized.

[0008] S2: Control the X-axis direct drive motion stage and the Y-axis direct drive motion stage to make the emission point of the high-precision displacement sensor on the upper surface of the adjustment platform, and make an "S"-shaped point scanning motion relative to the adjustment platform at a certain interval, and make the sampling points evenly distributed on the upper surface of the adjustment platform; the high-precision displacement sensor obtains the corresponding sampling point (X ’ , Y ’ ) coordinate height point cloud data, recorded as Z ’ , where for the starting point (X1 ’ , Y1 ’ ) coordinate height point cloud data, recorded as Z1 ’ , we can get the relative position of any subsequent scanning point to the starting point (X1 ’ , Y1 ’ ) height direction runout error: △Z ’ =Z ’ -Z1 ’ ;

[0009] S3: The height point cloud data Z obtained in step S2 ’The following processing is performed: (a) Use the 3σ criterion to eliminate gross errors; (b) Use the neighborhood interpolation method to fill in the gaps; (c) Use the regular grid triangulation method to establish a unitized grid, and split each quadrilateral grid unit into two triangles according to the upper right corner and the lower left corner; (d) Based on the triangulation result, use the bilinear interpolation method to calculate the height data corresponding to the coordinates of any interpolation point and record it as Z ’’ ;

[0010] S4: Height point cloud data Z ’ After processing, the coordinates of any point within the point scanning boundary can be obtained (X ’’ , Y ’’ ) corresponds to the height data Z ’’ and the point relative to the starting point (X1 ’ , Y1 ’ )Runout error in height direction: △Z ’’ =Z ’’ -Z1 ’ ;

[0011] S5: The sample to be tested is placed on the adjustment platform, and the high-precision displacement sensor performs point scanning on the sample to make its scanning range within the boundary of the adjustment platform point scanning range, and make its first scanning point coordinate (X1 ’’’ , Y1 ’’’ ) and the starting point coordinates (X1 ’ , Y1 ’ ) are consistent, and then the coordinates of any scanning point are marked as (X ’’’ , Y ’’’ ), the height data measured by the high-precision displacement sensor is recorded as Z ’’’ ; The obtained height point cloud data Z ’’’ After being processed by methods (a), (b) and (c) in S3, the bilinear interpolation method (d) in S3 is used to calculate the value of any scan point (X ’’’ , Y ’’’ ) corresponds to the height data when there is no sample to be measured, recorded as Z ’’ , then any scanning point relative to the starting point (X1 ’ , Y1 ’ ) of the original height runout error: △ Z ’’’ =Z ’’ -Z1 ’ , then the height point cloud data of the measured sample after correcting the original height jump error is obtained: Z R =Z ’’’ -△Z ’’’ .

[0012] Further preferably, the adjustment platform adopts a marble adjustment platform; the Y-direction direct-drive motion platform includes a first linear guide rail and a first platform, and the first linear guide rail is symmetrically arranged on the base along the Y direction; the first platform is slidably connected to the first linear guide rail through a first connecting slide, and a matching first linear motor magnetic rail and a first linear motor coil are provided between the two first linear guide rails, the first linear motor magnetic rail is fixed to the bottom of the first platform, and the first linear motor coil is fixed on the base; when the first linear motor coil is energized, the first linear motor magnetic rail and the first platform move along the first linear guide rail to realize Y-direction stable adjustment of the Y-direction direct-drive motion platform.

[0013] Further preferably, a first grating scale is provided along the Y direction at the bottom of the first platform, the first grating scale is located on one side of one of the first linear guide rails, and a first reading head is provided on the side of the first grating scale facing the magnetic track of the first linear motor; two first fixed limit blocks are also provided on the base along the Y direction, and a first moving limit block is provided at the bottom of the first platform, and the first moving limit block moves with the first platform between the two first fixed limit blocks.

[0014] Further preferably, the X-axis direct-drive motion stage includes a second linear guide and a second platform, the second linear guide being symmetrically arranged along the X-direction on the first platform; the second platform being slidably connected to the second linear guide via a second connecting slide, a second linear motor magnetic track and a second linear motor coil being provided between the two second linear guides, the second linear motor magnetic track being fixed to the bottom of the second platform, and the second linear motor coil being fixed to the first platform. When the second linear motor coil is energized, the second linear motor magnetic track and the second platform move along the second linear guide, thereby achieving stable X-axis adjustment of the X-axis direct-drive motion stage.

[0015] Further preferably, a second grating scale is provided along the X-direction at the bottom of the second platform, the second grating scale is located on one side of one of the second linear guide rails, and a second reading head is provided on the side of the second grating scale facing the second linear motor magnetic track; two second fixed limit blocks are also provided along the X-direction on the upper side of the first platform, and a second moving limit block is provided at the bottom of the second platform, and the second moving limit block moves with the second platform between the two second fixed limit blocks.

[0016] It is further preferred that the adjusting platform is centrally arranged on the upper surface of the second platform, and is provided with at least three leveling screws and at least two locking screws relative to the second platform; the adjusting platform is evenly provided with at least three through holes along its central axis, and threaded sleeves are fixed in the through holes; the leveling screws are threadedly connected to the threaded sleeves, and the second platform is provided with positioning blind holes that match the leveling screws; at least two vertical countersunk holes are symmetrically provided in the middle of the adjusting platform, and threaded holes corresponding to the vertical countersunk holes are provided on the second platform, and the locking screws are threadedly connected to the threaded holes after passing through the vertical countersunk holes; the height of the adjusting platform is adjusted by rotating the leveling screw, and when it is in a suitable position and state, the locking screw is rotated to lock the adjusting platform. The above adjustment is used for leveling the adjusting platform and locking it after leveling to improve measurement accuracy.

[0017] Further preferably, the vertical screw module includes a vertical support arranged on the gantry column, the vertical support is provided with a vertically arranged first screw and a first guide rail, the first screw is threadedly connected to the first slide, the first slide slides with the first guide rail, and the upper end of the first screw is connected to the first motor arranged on the vertical support; the turntable is arranged on the front panel of the first slide, and the swing table is arranged on the front panel of the turntable; the swing table is provided with a clamping seat for fixing the high-precision displacement sensor.

[0018] It is further preferred that the turntable is connected to the first slide through an adapter plate, and the turntable includes a fixed seat and a limit seat rotatably arranged on the adapter plate, and the fixed seat is rotatably provided with a circular table with a scale and an arc-shaped baffle matching the circular table; a rotating shaft is provided on the outer side of the circular table, and a limit slot is provided on the limit seat, and the end of the rotating shaft extends into the limit slot, and the limit seat is provided with a driving screw connected to the circular table through a worm gear.

[0019] Further preferably, the swing platform includes a matching arc base and an arc swing platform, an arc rail is provided in the arc base, an arc groove is provided at the bottom of the arc swing platform, the arc rail and the arc groove are slidably matched, a driving worm is provided on the arc base, a worm rack is provided at the bottom of the arc swing platform, and the driving worm is engaged with the worm rack; a limit rod is provided on one side of the arc swing platform, a limit plate is provided on one side of the arc base, an arc limit groove is provided on the limit plate, and the limit rod is located in the arc limit groove.

[0020] The beneficial effects of the present invention are as follows: the present invention utilizes the high-precision displacement sensor provided by the point scanning profiler to effectively reduce the influence of the runout error of the X-axis direct-drive motion stage and the Y-axis direct-drive motion stage during movement on the measurement results of the sample height information; and the non-contact measurement adopted avoids friction and wear between the probe and the sample while ensuring the measurement efficiency, thereby effectively ensuring the accuracy of the sample topography measurement.

[0021] The point scanning profiler of the present invention adopts an X-axis direct-drive motion stage and a Y-axis direct-drive motion stage driven by a linear motor to directly generate linear motion, greatly simplifying the structure, reducing the motion inertia, and significantly improving the dynamic response performance and positioning accuracy. In combination with an indium steel grating ruler, it can achieve micron-level or even nanometer-level precision control, which is suitable for high-precision, high-efficiency and high-dynamic performance applications, further improving measurement accuracy.

[0022] The method for correcting height-direction runout error of the present invention utilizes the high-precision displacement sensor of the point scanning profilometer to obtain the surface error after the superposition of the motion of the first linear guide and the second linear guide through a single point scan. Afterwards, as long as the measured sample is within the above-mentioned point scanning boundary, the guide rail runout error at the corresponding coordinate of the measured sample can be obtained through the bilinear interpolation method. This part of the error is subtracted from the height data of the measured sample to obtain the true height change data of the sample surface, thereby realizing the correction of the height-direction runout error of the point scanning profilometer conveniently and quickly. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0024] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0025] Figure 2 Schematic diagram of the Y-axis direct-drive motion stage structure;

[0026] Figure 3 This is a schematic diagram of the X-axis direct-drive motion stage structure;

[0027] Figure 4 This is a schematic diagram of the adjustment platform structure;

[0028] Figure 5 It is a schematic diagram of the vertical screw module structure;

[0029] Figure 6 It is a schematic diagram of the vertical motion component structure;

[0030] Figure 7 Point cloud data obtained by scanning the upper surface of the adjustment platform with a high-precision displacement sensor;

[0031] Figure 8 It is the runout error curve of the single slider linear guide in height direction;

[0032] Figure 9 Schematic diagram of the principle of filling gaps in height point cloud data using the neighborhood interpolation method;

[0033] Figure 10 This is a schematic diagram of the height point cloud data after processing and establishing a triangulated mesh;

[0034] Figure 11 For any non-scanning (X ’’ , Y ’’ ) coordinate interpolation to get Z ’’ Schematic diagram of the spatial points after the triangulation;

[0035] Figure 12 Schematic diagram of the principle of using bilinear interpolation to calculate the height data corresponding to the coordinates of any interpolation point;

[0036] Figure 13 The point cloud data obtained by the high-precision displacement sensor scanning the surface of the sample to be measured is used to make a grid diagram after triangulation after removing gross errors and filling the eliminated points;

[0037] Figure 14 Schematic diagram of the triangulated mesh obtained by scanning the point cloud data obtained from the surface of the sample under test and correcting the motion stage runout error. DETAILED DESCRIPTION

[0038] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0039] Example 1, as Figure 1As shown, a point scanning profilometer includes a base 1, which can adopt a marble base as the supporting structure of the entire point scanning profilometer. The base 1 is provided with a gantry column 2 and a Y-direction direct-drive motion platform 12, and the gantry column 2 is vertically arranged on the base. The gantry column 2 is provided with a vertical screw module 3, and the vertical screw module 3 is provided with a vertical motion component; the vertical screw module drives the vertical motion component to move in the Z direction to adjust the height of the high-precision displacement sensor. In this embodiment, the vertical motion component includes a turntable 5 and a swing table 6 connected to each other; the swing table 6 is provided with a high-precision displacement sensor 8; the turntable 5 provides the high-precision displacement sensor 8 with a degree of freedom of rotation in the vertical plane; the swing table 6 provides the high-precision displacement sensor 8 with a degree of freedom of swing in the vertical plane. In this embodiment, as a preference, the high-precision displacement sensor is a spectral confocal probe, and its light output mode is end-face light output; it is used to measure the height information of the morphology of the sample being measured. An X-direction direct-drive motion stage 11 is mounted on the Y-direction direct-drive motion stage 12. The Y-direction direct-drive motion stage 12 provides the sample with freedom of motion in the Y-direction, while the X-direction direct-drive motion stage 11 provides the sample with freedom of motion in the X-direction. An adjustment platform 10 is mounted on the X-direction direct-drive motion stage 11 for placing the sample. The adjustment platform is preferably a marble adjustment platform. The vertical motion assembly and adjustment platform 10 are used to adjust the light output angle of the high-precision displacement sensor relative to the sample. The Y-direction direct-drive motion stage and the X-direction direct-drive motion stage move in conjunction, allowing the light output point of the high-precision displacement sensor to perform an "S"-shaped point scanning motion across the surface of the sample at a predetermined interval.

[0040] In this embodiment, the point scanning topography instrument uses its own high-precision displacement sensor to effectively reduce the impact of the runout error during the movement of the X-axis direct-drive motion stage and the Y-axis direct-drive motion stage on the measurement results of the sample height information; the non-contact measurement adopted not only ensures the measurement efficiency, but also avoids friction and wear between the probe and the sample, effectively ensuring the accuracy of the sample topography measurement.

[0041] Example 2, as Figure 2 and Figure 3As shown, a point scanning profilometer is further optimized on the basis of Example 1. In this embodiment, the Y-direction direct-drive motion platform 12 includes a first linear guide rail 121 and a first platform 119. The first linear guide rail 121 is symmetrically arranged on the base 1 along the Y direction; that is, a double guide rail is used to ensure the stability of the Y-direction movement. The first platform 119 is slidably connected to the first linear guide rail 121 through a first connecting slide 129. In this embodiment, four first connecting slides are taken as an example, and two corresponding first connecting slides are arranged on each linear guide rail. A matching first linear motor magnetic rail 122 and a first linear motor coil 123 are provided between the two first linear guide rails 121 to form a linear motor; the first linear motor magnetic rail 122 is fixed to the bottom of the first platform 119, and the first linear motor coil 123 is fixed to the base 1. Preferably, the first linear motor coil 123 is fixed to the base through a first coil mounting seat 124 to ensure the stability of the installation. When the first linear motor coil is energized, the first linear motor magnetic track and the first platform move along the first linear guide rail, enabling the Y-axis direct-drive motion stage to stabilize the X-axis direct-drive motion stage and the adjustment platform in the Y direction. Linear motors eliminate the need for an intermediate transmission mechanism and directly generate linear motion, significantly simplifying their structure and improving dynamic response and positioning accuracy. Linear motors can achieve micron- and even nanometer-level precision control, making them suitable for applications requiring high precision, high efficiency, and high dynamic performance, further enhancing measurement accuracy.

[0042] In this embodiment, a first grating scale 126 is provided at the bottom of the first platform 119 along the Y direction. The first grating scale 126 is located on one side of one of the first linear guide rails 121. A first reading head 125 is provided on the side of the first grating scale 126 facing the first linear motor magnetic track 122. The first reading head 125 performs non-contact measurement on the first grating scale 126, thereby measuring the Y-direction movement distance of the first platform 119. The grating scale acts as a position feedback element, and the optical reading head detects the scale lines on the grating scale and converts the physical displacement into an electrical signal output. Its measurement accuracy is extremely high, usually reaching the micron or even submicron level. Two first fixed limit blocks 127 are also provided on the base 1 along the Y direction. The two first fixed limit blocks 127 are located at their two set extreme positions. A first moving limit block 128 is provided at the bottom of the first platform 119. The first moving limit block 128 moves with the first platform 119 between the two first fixed limit blocks 127. It is used to limit the maximum displacement of the first platform 119 to ensure the effectiveness of the measurement. In addition, the first grating ruler 126 cooperates with the reading head to realize the measurement and feedback of the Y-axis motion position. The fixed limit block and the motion limit block can prevent the Y-axis direct-drive motion stage 12 from exceeding the predetermined range and causing accidents or damaging the equipment.

[0043] As a preferred embodiment, Figure 3 and Figure 4As shown, the X-direction direct-drive motion platform 11 is similar in structure to the Y-direction direct-drive motion platform 12. Specifically, the X-direction direct-drive motion platform 11 includes a second linear guide 111 and a second platform 103. The second linear guide 111 is symmetrically arranged on the first platform 119 along the X-direction, that is, a double guide rail is used to ensure the stability of the X-direction movement. The second platform 103 is slidably connected to the second linear guide 111 through a second connecting slide 109. Similarly, in this embodiment, four second connecting slides are taken as an example, and two corresponding second connecting slides are set on each linear guide. A matching second linear motor magnetic rail 112 and a second linear motor coil 113 are provided between the two second linear guides 111 to form a linear motor. The second linear motor magnetic rail 112 is fixed to the bottom of the second platform 103, and the second linear motor coil 113 is fixed to the first platform 119. Preferably, the second linear motor coil 113 is fixed to the base through a second coil mounting seat 114 to ensure the stability of the installation. The second linear motor coil is energized, and the second linear motor magnetic track and the second platform move along the second linear guide rail to achieve X-direction stable adjustment of the X-direction direct-drive motion stage adjustment platform.

[0044] In this embodiment, a second scale 116 is provided along the X-axis at the bottom of the second platform 103. This scale 116 is located on one side of one of the second linear guide rails 111. A second reading head 115 is provided on the side of the scale 116 facing the second linear motor track 112. The second reading head 115 performs non-contact measurement on the scale 116, thereby measuring the X-axis movement distance of the second platform 103. Two second fixed stoppers 117 are also provided along the X-axis on the first platform 119, located at their two predetermined extreme positions. A second moving stopper 118 is provided at the bottom of the second platform 103. This second moving stopper 118 moves with the second platform 103 between the two second fixed stoppers 117, limiting the maximum displacement of the second platform 103 and ensuring measurement validity. The second scale 116 and the reading head simultaneously measure and provide feedback on the X-axis motion position. The fixed and moving stoppers prevent the X-axis direct-drive motion stage 11 from exceeding the predetermined range, potentially causing accidents or equipment damage. The Y-direction direct-drive motion stage 12 and the X-direction direct-drive motion stage 11 cooperate with each other to realize the point scanning motion of the outgoing light spot of the high-precision displacement sensor 8 on the surface of the measured topography.

[0045] like Figure 4As shown, the adjustment platform 10 is centrally located on the upper surface of the second platform 103 and is provided with at least three leveling screws 101 and at least two locking screws 102 relative to the second platform 103. In this embodiment, three leveling screws 101 and two locking screws 102 are used as an example. The three leveling screws 101 are arranged in an equilateral triangle along the central axis of the adjustment platform 10; the two locking screws 102 are symmetrically distributed in the middle of the adjustment platform 10. The three leveling screws 101 are used to adjust the level of the adjustment platform 10, and the two locking screws 102 are used to tighten and loosen the adjustment platform 10. In this embodiment, the adjustment platform 10 is provided with three through-holes evenly spaced along its central axis, each of which is fixedly embedded with a threaded sleeve. A leveling screw 101 is threadedly connected to the threaded sleeve, and a positioning blind hole is provided on the second platform 103 to match the leveling screw 101. The leveling screws 101 are rotated to change the length of the leveling screw 101 extending from the adjustment platform 10, and the end surface of the leveling screw 101 presses against the bottom surface of the positioning blind hole, thereby adjusting the levelness of the adjustment platform 10. Two vertical countersunk holes are symmetrically provided in the middle of the adjustment platform 10, and two threaded holes corresponding to the vertical countersunk holes are provided on the second platform 103. Locking screws 102 pass through the vertical countersunk holes and are threadedly connected to the threaded holes. When the adjustment platform 10 is in the desired position, the locking screws 102 are tightened to lock the adjustment platform 10.

[0046] like Figure 5 As shown, the vertical screw module 3 described in this embodiment includes a vertical support 31 fixedly mounted on the gantry column 2, and a vertically mounted first screw 32 and a first guide rail 33 are provided on the vertical support 31. The upper and lower ends of the first screw 32 are rotatably connected to the vertical support 31 via bearings. A first slide 34 is threadedly connected to the first screw 32, and the first slide 34 is fixedly connected to the slider of the first guide rail 33 and slides with the first guide rail 33. The upper end of the first screw 32 is connected to a first motor 35 provided on the vertical support 31; the rotation of the first motor drives the first screw to rotate, thereby driving the first slide to move up and down along the first guide rail. The turntable 5 is arranged on the front panel of the first slide 34 and slides up and down synchronously with the first slide. The swinging table 6 is arranged on the front panel of the turntable 5 and moves accordingly with the turntable 5. The swinging table 6 is provided with a clamping seat 7 for fixing the high-precision displacement sensor 8, and the clamping seat 7 clamps the high-precision displacement sensor 8. The turntable 5 cooperates with the swinging table 6 to adjust the light output angle of the high-precision displacement sensor 8 to ensure that the output light of the high-precision displacement sensor 8 is perpendicular to the surface of the sample to be measured.

[0047] Example 3, as Figure 6As shown, a point scanning profilometer is further optimized on the basis of Example 1. In this embodiment, the turntable 5 is connected to the first slide 34 via an adapter plate 4, and the adapter plate 4 is connected to the first slide via a bolt. The turntable 5 includes a fixed seat 51 and a limit seat 54 rotatably arranged on the adapter plate 4, and the fixed seat is fixed on the adapter plate. A circular table 52 with a scale and an arc-shaped baffle 56 cooperating with the circular table 52 are rotatably provided on the fixed seat 51; 2 to 3 arc-shaped baffles can be provided to limit the circular table and ensure its stable rotation; corresponding scales can also be provided on the arc-shaped baffle. A rotating shaft 53 is provided on the outer side of the circular table 52, and a limit slot 55 is provided on the limit seat 54. The limit slot 55 is a vertical through slot. The end of the rotating shaft 53 extends into the limit slot 55. Tightening the rotating shaft 53 can be used to limit the position of the circular table. The stopper seat 54 is equipped with a drive screw 57, which is connected to the circular platform 52 via a worm gear. The drive screw 57 is threadedly connected to the stopper seat. The drive screws 57 are symmetrically arranged on the upper and lower sides of the vertical through-slot. Rotating the drive screws 57 drives the circular platform 52. A corresponding handle is provided on the drive screw 57 for easy manual adjustment.

[0048] The swing platform 6 in this embodiment comprises a matching curved base 61 and a curved swing platform 62. The curved base 61 is fixed to the circular platform. A curved rail 63 is provided within the curved base 61, and a curved groove is provided at the bottom of the curved swing platform 62. The curved rail 63 slidably engages with the groove, allowing the curved swing platform to move only along the curved rail. The arc base 61 is provided with a driving worm 65, which is rotatably connected to the arc base through a bearing. A worm rack 66 is provided at the bottom of the arc swing platform 62, and the driving worm 65 is meshed with the worm rack 66 to form a worm gear structure similar to that of a worm gear; a handle is provided at the end of the driving worm 65 for easy manual adjustment, and the driving worm 65 is manually rotated forward and backward, and the driving worm 65 drives the worm rack and the arc swing platform to swing, thereby realizing the up and down swing of the arc swing platform; a limiting rod 67 is provided on one side of the arc swing platform 62, and a limiting plate 68 is provided on one side of the arc base 61, and an arc limiting groove 69 is provided on the limiting plate 68. The limiting rod 67 is located in the arc limiting groove 69, and is used to lock the arc swing platform 62 after it is in place.

[0049] Example 4, a method for correcting the height runout error of a point scanning profiler, using the point scanning profiler described in Example 2 or 3, with the following steps: S1: Adjust the adjustment platform 10 to keep it horizontal; then adjust the height of the high-precision displacement sensor 8, adjust the high-precision displacement sensor 8 downward through the vertical screw module, so that the overall surface height change information of the adjustment platform 10 is within the range of the high-precision displacement sensor 8, and adjust the turntable 5 and swing table 6 on the vertical motion assembly to minimize the height measurement result of the high-precision displacement sensor 8 at a certain scanning point. The specific method of adjusting the adjustment platform 10 is to loosen the two locking screws 102 on the adjustment platform 10, adjust the three leveling screws 101 on the adjustment platform 10 respectively to keep the adjustment platform 10 horizontal, and then tighten the two locking screws 102.

[0050] S2: Control the X-direction direct drive motion stage 11 and the Y-direction direct drive motion stage 12 to move, so that the emission light point of the high-precision displacement sensor 8 is on the upper surface of the adjustment platform 10, and performs an "S"-shaped point scanning motion relative to the adjustment platform 10 at a certain interval, and the sampling points are evenly distributed on the upper surface of the adjustment platform 10; the high-precision displacement sensor 8 obtains the corresponding sampling point (X ’ , Y ’ ) coordinate height point cloud data, recorded as Z ’ , where for the starting point (X1 ’ , Y1 ’ ) coordinate height point cloud data, recorded as Z1 ’ , we can get the relative position of any point thereafter to the starting point (X1 ’ , Y1 ’ ) height direction runout error: △Z ’ =Z ’ -Z1 ’ Specifically, the X-direction direct-drive motion stage 11 and the Y-direction direct-drive motion stage 12 are controlled to move, so that the light point emitted by the high-precision displacement sensor 8 performs an "S"-shaped point scanning motion on the upper surface of the adjustment platform 10. The distance between two adjacent points in the X and Y directions is 0.5 mm, and the scanning range is a 50 mm x 50 mm square area, which is located in the center of the upper surface of the adjustment platform 10. The point cloud data obtained is as follows: Figure 7 As shown, due to Figure 8 Due to the presence of factors such as the height runout error of the linear guide rail shown in the figure, the point cloud data obtained by the high-precision displacement sensor 8 scanning the upper surface of the fine-ground adjustment platform 10 still deviates from the same plane. The height runout error of the linear guide rail causes runout errors at different positions of the X-axis direct-drive motion platform 11 and the Y-axis direct-drive motion platform 12, which can be regarded as repeatability errors and can be compensated or corrected by relevant methods. The high-precision displacement sensor 8 obtains the corresponding (X ’ , Y ’ ) coordinate height point cloud data, recorded as Z’ , where for the starting point (X1 ’ , Y1 ’ ) coordinate height point cloud data, recorded as Z1 ’ , we can get the relative position of any point thereafter to the starting point (X1 ’ , Y1 ’ ) height direction runout error: △Z ’ =Z ’ -Z1 ’ ;

[0051] S3: The height point cloud data Z obtained in step S2 ’ Perform discrete point optimization and grid interpolation processing and record it as Z ’’ . For the height point cloud data Z obtained in step S2 ’ The specific steps for discrete point optimization and grid interpolation are as follows: (a) Use the 3σ criterion to eliminate gross errors; specifically, calculate the Z of the 10201 data points obtained from the above scan. ’ The mean and standard deviation of are denoted as μ and σ respectively. Traverse the above 10201 data points Z ’ , when Z ’ If the data point is not within the interval (μ-3σ, μ+3σ), the data point will be eliminated.

[0052] (b) Use neighborhood interpolation to fill in the gaps; specifically: Figure 9 As shown in the figure, the collected data points are observed from a bird's-eye view, with the horizontal right direction being the X direction, the vertical upward direction being the Y direction, and the direction perpendicular to the XY plane being the Z direction. For data points that may be eliminated, four situations are listed: ① If Figure 9 As shown in (a), when there is one elimination point inside the point cloud data, use (Z a1 ’ +Z a2 ’ +Z a3 ’ +Z a4 ’ ) / 4 to represent the height value at that point;② Figure 9 As shown in (b), when there are two elimination points inside the point cloud data, use (Z b1 ’ +Z b2 ’ +Z b3 ’ ) / 3 to represent the height value of the previous point, and use (Z b4 ’ +Z b5 ’ +Z b6 ’) / 3 to represent the height value of the next point; ③ For example Figure 9 As shown in (c), when there is a point to be removed on the boundary of the point cloud data, (Z c1 ’ +Z c2 ’ +Z c3 ’ ) / 3 to represent the height value at that point; ④ Figure 9 As shown in (d), when there is a point to be eliminated at the corner of the point cloud data, use (Z d1 ’ +Z d2 ’ ) / 2 to represent the height value at that point. The same applies to other cases. The height value of the removed point is filled with the average of the height values ​​of the adjacent removed points. If there are multiple removed points in a certain area, the filling starts from the edge of the area with adjacent points.

[0053] (c) Use the regular grid triangulation method to establish a unitized grid, and split each quadrilateral grid unit into two triangles according to the upper right corner and the lower left corner; Figure 10 and Figure 11 shown.

[0054] (d) According to the segmentation results, the bilinear interpolation method is used to calculate the height data corresponding to the coordinates of any interpolation point, and it is recorded as Z ’’ Specifically: Figure 12 As shown, the collected data points are observed from a bird's-eye view, with the horizontal right direction being the X direction, the vertical upward direction being the Y direction, and the direction perpendicular to the XY plane being the Z direction. Specify any point within the above scanning area. Case 1: The point is located inside the triangle at the lower left corner of the triangular grid. The grating scale (encoder) of the X-direction direct-drive motion stage and the Y-direction direct-drive motion stage, as well as the high-precision displacement sensor (spectral confocal probe), can read the vertex coordinates of the triangle at the lower left corner. Let them be (X1 ’ , Y1 ’ , Z1 ’ )、(X1 ’ , Y1 ’ +0.5, Z2 ’ ) and (X1 ’ +0.5, Y1 ’ +0.5, Z3 ’ ), the X and Y coordinates of any specified point are (X1 ’ +dX,Y1 ’ +dY), the coordinate is read by the grating ruler (encoder) of the X-direction direct drive motion stage and the Y-direction direct drive motion stage, so dX and dY are known, then the height value Z corresponding to this point ’’ =Z1 ’+(Z2 ’ -Z1 ’ )×dY / 0.5+(Z3 ’ -Z2 ’ )×dX / 0.5; Case 2: The point is located inside the triangle at the upper right corner of the triangular grid. The grating scale (encoder) of the X-direction direct drive motion stage and the Y-direction direct drive motion stage and the high-precision displacement sensor (spectral confocal probe) can read the vertex coordinates of the triangle at the upper right corner, which are set as (X1 ’ , Y1 ’ , Z1 ’ )、(X1 ’ +0.5, Y1 ’ , Z4 ’ ) and (X1 ’ +0.5, Y1 ’ +0.5, Z3 ’ ), the X and Y coordinates of any specified point are still assumed to be (X1 ’ +dX,Y1 ’ +dY), as above, so dX and dY are known, then the height value Z corresponding to the point ’’ =Z1 ’ +(Z4 ’ -Z1 ’ )×dX / 0.5+(Z3 ’ -Z4 ’ )×dY / 0.5. After point verification, the obtained spatial point is on the triangulated mesh surface, such as Figure 11 shown.

[0055] S4: Height point cloud data Z ’ After processing, the coordinates of any point within the point scanning boundary can be obtained (X ’’ , Y ’’ ) corresponds to the height data Z ’’ and the point relative to the starting point (X1 ’ , Y1 ’ )Runout error in height direction: △Z ’’ =Z ’’ -Z1 ’ In this example, the height point cloud data of a limited number of coordinate points (10201) can be obtained by intermittent scanning. After processing by the above methods (a) to (d), the coordinates (X ’’ , Y ’’ ) corresponds to the height data Z ’’ , we can also get the relative value of any point to the starting point (X1 ’ , Y1 ’ )Runout error in height direction: △Z ’’=Z ’’ -Z1 ’ , laying the foundation for correcting or compensating the runout error of the guide rail in the height direction at any point.

[0056] S5: The sample 9 to be tested is placed on the adjustment platform 10. The high-precision displacement sensor 8 performs point scanning on the sample 9 to make its scanning range within the boundary of the adjustment platform point scanning range (50mmx50mm) and make its first scanning point coordinate (X1 ’’’ , Y1 ’’’ ) and the starting point coordinates (X1 ’ , Y1 ’ ) are consistent, and then the coordinates of any scanning point are marked as (X ’’’ , Y ’’’ ), the height data measured by the high-precision displacement sensor 8 is recorded as Z ’’’ ; The obtained height point cloud data Z ’’’ After being processed by methods (a), (b) and (c) in S3, the bilinear interpolation method (d) in S3 is used to calculate the value of any scan point (X ’’’ , Y ’’’ ) corresponds to the height data when there is no sample to be measured, recorded as Z ’’ , then any scanning point relative to the starting point (X1 ’ , Y1 ’ ) of the original height runout error: △ Z ’’’ =Z ’’ -Z1 ’ , then the height point cloud data of the measured sample 9 after correcting the original height jump error is obtained: Z R =Z ’’’ -△Z ’’’ Specifically: perform point scanning on the sample 9 to make its scanning range (measurement area) within the boundary of the above-mentioned 50mmx50mm scanning area, and make its first scanning point coordinate (X1 ’’’ , Y1 ’’’ ) and the above starting point coordinates (X1 ’ , Y1 ’ ) are consistent, and then the coordinates of any scanning point are marked as (X ’’’ , Y ’’’ ), the height data measured by the high-precision displacement sensor 8 is recorded as Z ’’’ , the obtained point cloud data is (a) eliminated of gross errors and (b) filled with eliminated points, and then (c) mesh triangulation is performed, as shown in Figure 13 As shown; By the bilinear interpolation method (d) above, the arbitrary point (X ’’’ , Y ’’’ ) in the height direction: Z ’’and the arbitrary point relative to the starting point (X1 ’ , Y1 ’ ) of the original height direction runout error: △ Z ’’’ =Z ’’ -Z1 ’ (caused by the rail runout), then the height point cloud data of the measured sample 9 after correcting the original height runout error is obtained: Z R =Z ’’’ -△Z ’’’ ,like Figure 14 shown.

[0057] In summary, the present invention utilizes the high-precision displacement sensor of the point scanning topography instrument to effectively reduce the influence of the guide rail runout error during the movement of the X- and Y-direction direct-drive motion stages on the measurement results of the sample height information; the non-contact measurement avoids friction and wear between the probe and the sample while ensuring measurement efficiency, and effectively ensures the accuracy of the sample morphology measurement.

[0058] It should be noted that the present invention improves the equipment components and measurement methods, and does not involve improvements to the circuits and control programs. The present invention only controls the operation and stop of various electronic devices through the PLC control system. Since the PLC control system is a mature automatic control system in industry, the present invention will not go into details about the circuits and control programs.

[0059] In the description of the present invention, it should be understood that the terms "vertical", "lateral", "up", "down", "front", "back", "left", "right", "horizontal", "top", "bottom", "inside" and "outside" and the like to indicate directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are merely simplified descriptions for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0060] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for correcting the height runout error of a point scanning profiler, characterized by: The steps are as follows: S1: adjust the adjustment platform (10) to keep it horizontal; then adjust the height of the high-precision displacement sensor (8) so that the overall surface height change information of the adjustment platform (10) is within the range of the high-precision displacement sensor (8); adjust the turntable (5) and the swing table (6) on the vertical motion component so that the height measurement result of the high-precision displacement sensor (8) at a certain scanning point is minimized; S2: Control the movement of the X-direction direct drive motion stage (11) and the Y-direction direct drive motion stage (12), so that the light point emitted by the high-precision displacement sensor (8) is on the upper surface of the adjustment platform (10), and performs an "S"-shaped point scanning movement relative to the adjustment platform (10) at a certain interval, and the scanning points are evenly distributed on the upper surface of the adjustment platform (10); the high-precision displacement sensor (8) obtains the corresponding scanning point (X ’ , Y ’ ) coordinate height point cloud data, recorded as Z ’ , where for the starting point (X1 ’ , Y1 ’ ) coordinate height point cloud data, recorded as Z1 ’ , then we can get the value of any subsequent scanning point relative to the starting point (X1 ’ , Y1 ’ ) height direction runout error: △Z ’ =Z ’ -Z1 ’ ; S3: The height point cloud data Z obtained in step S2 ’ Perform discrete point optimization and grid interpolation processing, and record it as Z ’’ ; S4: Height point cloud data Z ’ After discrete point optimization and grid interpolation processing, the coordinates of any point within the point scanning boundary (X ’’ , Y ’’ ) corresponds to the height data Z ’’ and the point relative to the starting point (X1 ’ , Y1 ’ )Runout error in height direction: △Z ’’ =Z ’’ -Z1 ’ ; S5: The sample to be tested (9) is placed on the adjustment platform (10), and the high-precision displacement sensor (8) performs point scanning on the sample to be tested (9), so that its scanning range is within the boundary of the adjustment platform point scanning range, and its first scanning point (X1 ’’’ , Y1 ’’’ ) coordinates and the starting point (X1 ’ , Y1 ’ ) coordinates are consistent, and then the coordinates of any scanning point are marked as (X ’’’ , Y ’’’ ), the height data measured by the high-precision displacement sensor (8) is recorded as the height point cloud data Z ’’’ ; The obtained height point cloud data Z ’’’ After being processed by methods (a), (b) and (c) in step S3, the bilinear interpolation method in step S3 (d) is used to calculate the value of any scan point (X ’’’ , Y ’’’ ) corresponds to the height data when there is no sample to be measured, recorded as Z ’’ , then any scanning point relative to the starting point (X1 ’ , Y1 ’ ) of the original height runout error: △ Z ’’’ =Z ’’ -Z1 ’ , then the height point cloud data of the measured sample (9) after correcting the original height jump error is obtained: Z R =Z ’’’ -△Z ’’’ .

2. The method for correcting the height runout error of a point scanning profiler according to claim 1, characterized in that: In step S3, the height point cloud data Z obtained in step S2 is ’ The specific steps for discrete point optimization and grid interpolation are as follows: (a) use the 3σ criterion to eliminate gross errors; (b) use the neighborhood interpolation method to fill in the gaps; (c) use the regular grid triangulation method to establish a unitized grid, and divide each quadrilateral grid unit into two triangles according to the upper right corner and the lower left corner; (d) according to the triangulation result, use the bilinear interpolation method to calculate the height data corresponding to the coordinates of any interpolation point and record it as Z ’’ .

3. The method for correcting the height runout error of a point scanning profiler according to claim 1 or 2, characterized in that: The point scanning profiler used comprises a base (1), wherein the base (1) is provided with a gantry column (2) and a Y-direction direct drive motion platform (12), the gantry column (2) is provided with a vertical screw module (3), and the vertical screw module (3) is provided with a vertical motion component; the vertical motion component comprises a rotary table (5) and an oscillating table (6) connected to each other; a high-precision displacement sensor (8) is provided on the oscillating table (6); an X-direction direct drive motion platform (11) is provided on the Y-direction direct drive motion platform (12); an adjustment platform (10) for placing a sample to be measured is provided on the X-direction direct drive motion platform (11); the vertical motion component and the adjustment platform (10) are used to adjust the light output angle of the high-precision displacement sensor (8) relative to the sample to be measured, and the Y-direction direct drive motion platform (12) and the X-direction direct drive motion platform (11) move in coordination so that the light output point of the high-precision displacement sensor (8) can perform an "S"-shaped point scanning motion on the surface of the sample to be measured at a certain interval.

4. The method for correcting the height runout error of a point scanning profiler according to claim 3, characterized in that: The adjustment platform (10) adopts a marble adjustment platform; the Y-direction direct-drive motion platform (12) includes a first linear guide rail (121) and a first platform (119), the first linear guide rail (121) is symmetrically arranged on the base (1) along the Y direction; the first platform (119) is slidably connected to the first linear guide rail (121) through a first connecting slide (129), and a matching first linear motor magnetic rail (122) and a first linear motor coil (123) are provided between the two first linear guide rails (121), the first linear motor magnetic rail (122) is fixed to the bottom of the first platform (119), and the first linear motor coil (123) is fixed on the base (1); A first grating ruler (126) is provided at the bottom of the first platform (119) along the Y direction. The first grating ruler (126) is located on one side of one of the first linear guide rails (121). A first reading head (125) is provided on the side of the first grating ruler (126) facing the first linear motor magnetic rail (122). Two first fixed limit blocks (127) are also provided on the base (1) along the Y direction. A first moving limit block (128) is provided at the bottom of the first platform (119). The first moving limit block (128) moves between the two first fixed limit blocks (127) along with the first platform (119).

5. The method for correcting the height runout error of a point scanning profiler according to claim 4, characterized in that: The X-direction direct-drive motion table (11) comprises a second linear guide rail (111) and a second platform (103), wherein the second linear guide rail (111) is symmetrically arranged on the first platform (119) along the X-direction; the second platform (103) is slidably connected to the second linear guide rail (111) via a second connecting slide (109); a second linear motor magnetic rail (112) and a second linear motor coil (113) that match each other are provided between the two second linear guide rails (111); the second linear motor magnetic rail (112) is fixed to the bottom of the second platform (103), and the second linear motor coil (113) is fixed on the first platform (119).

6. The method for correcting the height runout error of a point scanning profiler according to claim 5, characterized in that: A second grating ruler (116) is provided at the bottom of the second platform (103) along the X direction, the second grating ruler (116) is located on one side of one of the second linear guide rails (111), and a second reading head (115) is provided on the side of the second grating ruler (116) facing the second linear motor magnetic track (112); two second fixed limit blocks (117) are also provided on the first platform (119) along the X direction, a second moving limit block (118) is provided at the bottom of the second platform (103), and the second moving limit block (118) moves between the two second fixed limit blocks (117) along with the second platform (103).

7. The method for correcting the height runout error of a point scanning profiler according to claim 6, characterized in that: The adjusting platform (10) is centrally arranged on the upper surface of the second platform (103), and is provided with at least three leveling screws (101) and at least two locking screws (102) relative to the second platform (103); the adjusting platform (10) is evenly provided with at least three through holes along the central axis direction thereof, and threaded sleeves are fixedly provided in the through holes; the leveling screws (101) are threadedly connected in the threaded sleeves, and a positioning blind hole matching the leveling screws (101) is provided on the second platform (103); at least two vertical countersunk holes are symmetrically provided in the middle of the adjusting platform (10), and threaded holes corresponding to the vertical countersunk holes are provided on the second platform (103), and the locking screws (102) are threadedly connected to the threaded holes after passing through the vertical countersunk holes.

8. The method for correcting the height runout error of a point scanning profilometer according to any one of claims 4 to 7, characterized in that: The vertical screw rod module (3) includes a vertical support (31) arranged on the gantry column (2), a vertically arranged first screw rod (32) and a first guide rail (33) are provided on the vertical support (31), a first slide (34) is threadedly connected to the first screw rod (32), the first slide (34) and the first guide rail (33) are slidably matched, and the upper end of the first screw rod (32) is connected to a first motor (35) arranged on the vertical support (31); the turntable (5) is arranged on the front panel of the first slide (34), and the swing table (6) is arranged on the front panel of the turntable (5); and the swing table (6) is provided with a clamping seat (7) for fixing a high-precision displacement sensor (8).

9. The method for correcting the height runout error of a point scanning profiler according to claim 8, characterized in that: The turntable (5) is connected to the first slide (34) through the adapter plate (4). The turntable (5) includes a fixed seat (51) and a limit seat (54) rotatably arranged on the adapter plate (4). A scaled round table (52) and an arc-shaped baffle (56) matched with the round table (52) are rotatably provided on the fixed seat (51); a rotating shaft (53) is provided on the outer side of the round table (52); a limit slot (55) is provided on the limit seat (54), and an end of the rotating shaft (53) extends into the limit slot (55). A driving screw (57) connected to the round table (52) through a worm gear is provided on the limit seat (54).

10. The method for correcting the height runout error of a point scanning profiler according to claim 9, characterized in that: The swing platform (6) includes a matching arc base (61) and an arc swing platform (62), wherein an arc rail (63) is provided in the arc base (61), an arc groove is provided at the bottom of the arc swing platform (62), and the arc rail (63) is slidably matched with the arc groove. A driving worm (65) is provided on the arc base (61), and a worm gear rack (66) is provided at the bottom of the arc swing platform (62), and the driving worm (65) is meshed with the worm gear rack (66); a limiting rod (67) is provided on one side of the arc swing platform (62), and a limiting plate (68) is provided on one side of the arc base (61), an arc limiting groove (69) is provided on the limiting plate (68), and the limiting rod (67) is located in the arc limiting groove (69).

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