CN-122015702-A - White light interference attitude angle automatic correction method, system, device and storage medium

Abstract

The invention discloses a method, a system, a device and a storage medium for automatically correcting a white light interference attitude angle, wherein the method comprises the steps of obtaining an initial white light interference image obtained by a white light interference measurement system for measuring a sample; the method comprises the steps of obtaining an initial white light interference image, resolving the initial white light interference image to obtain at least one group of candidate attitude angles of a sample, wherein each group of candidate attitude angles comprise attitude angle components of the sample in at least two different axial directions, respectively adjusting the attitude of the sample according to each group of candidate attitude angles by using the carrier, obtaining stripe change information after each attitude adjustment, sequentially judging whether the stripe change information after each adjustment meets preset change conditions or not, determining the candidate attitude angle corresponding to the stripe change information meeting the preset change conditions as a target attitude angle, and finishing correction. According to the invention, through the combination of image analysis and adjustment verification, the automation and high-precision correction of the sample attitude angle are realized, and the accuracy and stability of white light interferometry can be remarkably improved.

Inventors

• ZHENG SHAOYU

Assignees

• 普雷赛斯(苏州)智能科技有限公司

Dates

Publication Date

20260512

Application Date

20260401

Claims (16)

1. 1. A method for automatically correcting a white light interferometric attitude angle, for use in a white light interferometry system including a carrier, the method comprising: Obtaining an initial white light interference image obtained by measuring a sample by a white light interference measuring system; resolving the initial white light interference image to obtain at least one group of candidate attitude angles of the sample, wherein each group of candidate attitude angles comprises attitude angle components of the sample in at least two different axial directions; And sequentially judging whether the stripe change information after each adjustment meets the preset change condition or not, and determining the candidate attitude angle corresponding to the stripe change information meeting the preset change condition as a target attitude angle to finish correction.
2. 2. The method of automatic correction of white light interference attitude angles according to claim 1, wherein each set of candidate attitude angles includes attitude angle components of the sample in a lateral direction and in a longitudinal direction; Calculating the initial white light interference image to obtain at least one set of candidate attitude angles of the sample, wherein the method comprises the following steps: Determining a reference point in the initial white light interference image, and respectively acquiring a gray level profile sequence along the transverse direction and the longitudinal direction by taking the reference point as the center; Respectively carrying out effective wave crest detection on the gray level profile sequences in each direction to obtain wave crest detection information corresponding to the gray level profile sequences in each direction; when the wave crest detection information indicates that no effective wave crest exists or only one effective wave crest exists in the gray scale section sequence in the corresponding direction, carrying out attitude angle assignment on the corresponding gray scale section sequence according to a preset rule to obtain an attitude angle component of the sample in the corresponding direction; when the peak detection information indicates that two or more effective peaks exist in the gray level profile sequence in the corresponding direction, a theoretical fringe period of the white light interferometry system is calculated in advance, and according to the theoretical fringe period and the peak detection information in the direction in which the effective peaks exist, an attitude angle component of the sample in the corresponding direction is calculated.
3. 3. The method according to claim 2, wherein the attitude angle component of the sample in the corresponding direction is assigned to 0 when the peak detection information indicates that there is no effective peak or only one effective peak in the gray-scale profile sequence in the corresponding direction.
4. 4. The method according to claim 2, wherein when the peak detection information indicates that the gray scale profile sequence in the corresponding direction has no effective peak, the peak detection information includes the number of effective peaks and the number of effective peaks is specifically 0; when the peak detection information indicates that two or more than two effective peaks exist in the gray level profile sequence in the corresponding direction, the peak detection information comprises the number of the effective peaks in the corresponding direction, the effective peak position of each effective peak and stripe spacing obtained based on the effective peak position and the effective peak number, and the effective peak number is more than or equal to 2; effective peak detection is carried out on the gray level profile sequences in each direction respectively to obtain peak detection information corresponding to the gray level profile sequences in each direction, and the method comprises the following steps: Optionally selecting a gray level profile sequence in one direction, detecting the selected gray level profile sequence by adopting a first-order differential sign change method, and determining a plurality of peak candidate points in the selected gray level profile sequence; carrying out validity judgment on all peak candidate points in the selected gray level profile sequence; marking the number of effective wave peaks in the selected gray level section sequence as 0 when all peak candidate points in the selected gray level section sequence are invalid, and marking the number of effective wave peaks in the selected gray level section sequence as 1 when only one of all peak candidate points in the selected gray level section sequence is valid; When at least two of all peak candidate points are effective, counting the number of effective peaks in the selected gray level profile sequence, and determining the position of each effective peak in the selected gray level profile sequence; determining a first peak position and a last peak position from all effective peak positions, and calculating corresponding fringe intervals according to the first peak position, the last peak position and the corresponding effective peak number; And acquiring peak detection information in another gray level profile sequence according to the same method.
5. 5. The method for automatically correcting a white light interference attitude angle according to claim 4, wherein specific calculation formulas of the fringe pitches in the lateral direction and the axial direction are respectively: ; where a and b are stripe spacing in the transverse and axial directions, respectively, N and M are effective peak numbers in the transverse and axial directions, u first and u last are the first and last peak positions in the transverse directions, respectively, and v first and v last are the first and last peak positions in the longitudinal directions, respectively.
6. 6. The method for automatically correcting a white light interference attitude angle according to claim 4, wherein the gray-scale profile sequence is composed of gray-scale values at a plurality of sampling points; detecting the selected gray level profile sequence by adopting a first-order differential sign change method, and determining a plurality of peak candidate points in the selected gray level profile sequence, wherein the method comprises the following steps: In the selected gray profile sequence, gray variation of each sampling point is calculated respectively, and the gray variation of each sampling point is defined as corresponding first-order difference; For the nth sampling point, if the first order difference of the nth sampling point is not more than 0 and the first order difference of the n-1 th sampling point is more than 0, judging the nth sampling point as a peak candidate point, otherwise judging the nth sampling point as not being the peak candidate point, traversing the first order difference of each sampling point in the selected gray profile sequence in turn according to the same judging method, and determining a plurality of peak candidate points in the selected gray profile sequence.
7. 7. The method for automatically correcting a white light interference attitude angle according to claim 4, wherein the gray-scale profile sequence is composed of gray-scale values at a plurality of sampling points; and judging the effectiveness of all peak candidate points in the selected gray level profile sequence, wherein the method comprises the following steps: Selecting a peak candidate point in the selected gray level profile sequence, when the difference value between the gray level value of the selected peak candidate point and the global gray level average value is greater than or equal to a preset significance threshold value, reserving the selected peak candidate point, otherwise, removing the selected peak candidate point; Traversing each peak candidate point in the selected gray level profile sequence, and screening all peak candidate points in the selected gray level profile sequence according to the same method; The method comprises the steps of screening residual peak candidate points, carrying out descending order according to the gray value, obtaining a peak candidate sequence, adopting a greedy selection method, sequentially selecting the peak candidate point with the highest current gray value from the peak candidate sequence as a potential peak, taking the potential peak as a center, removing the rest peak candidate points in the peak candidate sequence within a preset minimum interval range, and completing the validity judgment of the selected gray profile sequence and obtaining a corresponding effective peak set when all the peak candidate points in the peak candidate sequence are processed.
8. 8. The method according to claim 4, wherein the step of selecting peak detection information corresponding to a gray-scale profile sequence in one direction, and when the selected peak detection information indicates that two or more effective peaks exist in the gray-scale profile sequence in the corresponding direction, calculating an attitude angle component of the sample in the corresponding direction according to the theoretical fringe period and the peak detection information in the direction in which the effective peaks exist, includes: Calculating the absolute value of the attitude angle of the sample in the selected direction according to the theoretical fringe period and the fringe spacing in the selected direction; The specific calculation formulas of the absolute values of the attitude angles in the transverse direction and the axial direction are respectively as follows: ; Wherein, the And Absolute values of attitude angles in the transverse direction and the axial direction respectively, a and b are stripe intervals in the transverse direction and the axial direction respectively, and l is the theoretical stripe period; If the wave crest detection information corresponding to the gray level profile sequence in the other direction indicates that no effective wave crest exists in the corresponding direction, generating two attitude angle components with opposite attitude angle signs according to the absolute value of the attitude angle of the sample in the selected direction; if the peak detection information corresponding to the gray profile sequence in the other direction also indicates that an effective peak exists in the corresponding direction, two diagonals are constructed based on the reference point and the effective peak closest to the reference point in the two directions, gray variances corresponding to the two diagonals are obtained, the posture angle sign of the sample in the selected direction is determined according to the comparison result between the gray variances of the two diagonals, and the posture angle component of the sample in the selected direction is generated according to the posture angle absolute value and the posture angle sign of the sample in the selected direction.
9. 9. The method of automatic correction of white light interferometric attitude angle according to claim 2, characterized in that the theoretical fringe period of the white light interferometric measuring system is calculated in advance, comprising: Acquiring the spectrum distribution of the white light interferometry system, and converting the spectrum distribution to obtain a coherence function of the white light interferometry system; Determining a corresponding interference light intensity signal according to a coherence function of the white light interferometry system; and extracting an oscillation waveform of the interference light intensity signal near zero optical path difference, and obtaining the theoretical fringe period according to the oscillation waveform.
10. 10. The method for automatically correcting a white light interferometric attitude angle according to claim 9, wherein a specific formula for calculating a coherence function of the white light interferometric measuring system is: ; Wherein, the V is frequency, S (v) is spectral density obtained by frequency conversion of the spectral distribution, I is an imaginary unit for time delay; The specific formula for determining the interference light intensity signal is as follows: ; Wherein, the For the interference intensity signal of the white light interferometry system, To take the real part operation.
11. 11. The method according to claim 2, wherein acquiring the gray scale profile sequence in the lateral and longitudinal directions, respectively, with the reference point as a center, comprises: Drawing lines passing through the reference points in the initial white light interference image by taking the reference points as the center along the transverse direction and the longitudinal direction respectively to obtain transverse section lines and longitudinal section lines; respectively extracting pixel gray values of the transverse section line and the longitudinal section line to obtain a transverse initial gray level section image and a longitudinal initial gray level section image; Resampling and smoothing filtering are carried out on the transverse initial gray level profile image to obtain a transverse gray level profile sequence; and resampling and smoothing filtering the longitudinal initial gray level profile image to obtain a gray level profile sequence in the longitudinal direction.
12. 12. The method according to claim 1, wherein performing posture adjustment on the sample by using the carrier according to each set of candidate posture angles, and acquiring stripe change information after each posture adjustment, respectively, comprises: Respectively carrying out posture adjustment on the sample by utilizing the carrier according to each group of candidate posture angles, and acquiring an adjusted white light interference image after each posture adjustment; And respectively acquiring stripe change information after each gesture adjustment according to the initial white light interference image and the adjusted white light interference image after each gesture adjustment, wherein the stripe change information comprises stripe width change and stripe direction change.
13. 13. The method for automatically correcting a white light interference attitude angle according to claim 12, wherein sequentially judging whether the fringe variation information after each adjustment satisfies a preset variation condition, comprises: for the stripe change information after any posture adjustment, when the stripe width change indicates that the stripe width after adjustment is enlarged, and the stripe direction change indicates that the stripe direction after adjustment is approaching to the preset ideal direction, judging that the corresponding stripe change information meets the preset change condition, otherwise, judging that the corresponding stripe change information does not meet the preset change condition, and continuing the judgment of the stripe change information after the next adjustment.
14. 14. A white light interferometric attitude angle automatic correction system, characterized by being applied to the white light interferometric attitude angle automatic correction method according to any one of claims 1 to 13, the system comprising: The image acquisition module is used for acquiring an initial white light interference image obtained by measuring a sample by the white light interference measurement system; the gesture resolving module is used for resolving the initial white light interference image to obtain at least one group of candidate gesture angles of the sample, wherein each group of candidate gesture angles comprises gesture angle components of the sample in at least two different axial directions; The adjustment verification module is used for adjusting the posture of the sample by using the carrier according to each group of candidate posture angles respectively, acquiring stripe change information after each posture adjustment, sequentially judging whether the stripe change information after each adjustment meets a preset change condition, determining the candidate posture angle corresponding to the stripe change information meeting the preset change condition as a target posture angle, and finishing correction.
15. 15. A white light interferometric attitude angle automatic correction device, characterized by comprising a processor, a memory and a computer program stored in the memory and executable on the processor, the computer program when run implementing the method steps in the white light interferometric attitude angle automatic correction method according to any one of claims 1 to 13.
16. 16. A computer storage medium comprising at least one instruction which, when executed by a computer, implements the method steps in the white light interferometric attitude angle automatic correction method according to any one of claims 1 to 13.

Description

White light interference attitude angle automatic correction method, system, device and storage medium Technical Field The invention relates to the technical field of optical measurement, in particular to a method, a system, a device and a storage medium for automatically correcting a white light interference attitude angle. Background The white light interferometry technique plays an irreplaceable role in surface topography detection in the fields of integrated circuits, micro-electro-mechanical systems, precision optics and the like by virtue of the nano-scale vertical resolution and non-contact measurement advantages. In an automated measurement scenario, to achieve high-efficiency, high-batch continuous detection, it is often necessary to place the sample on a mechanical carrier for rapid positioning and scanning. However, due to factors such as mechanical positioning accuracy, sample clamping errors or carrier motion attitude changes, the samples or carriers often have unavoidable attitude angle (including pitch angle and roll angle) deviations. The deviation can be directly mapped into the interference pattern, so that the direction of the interference fringes is deflected, the fringe width (namely the space frequency) is changed, the alignment precision of an automatic focusing system and the stability of phase-shifting scanning are further affected, and the accuracy of three-dimensional morphology reconstruction and measurement repeatability are finally reduced. In the prior art, the tilt direction is determined for the extraction and analysis of fringe parameters, either focusing on the extraction of parameters of a specific type of fringe (such as moire fringes), or on the angular adjustment of a specific interference structure (such as a reference mirror or mirror inside a michelson interferometer), or by identifying the overall heading of the fringe. In these schemes, there are common drawbacks in that the stripe direction recognition and the attitude angle resolution are complicated, the coupling between the extraction of the stripe parameters and the closed-loop adjustment of the attitude angle is insufficient, and the angle resolution depends on the complicated stripe direction determination. Therefore, the existing fringe parameter extraction technology cannot effectively solve the fringe change problem caused by the deviation of the attitude angle of a sample/carrier in the automatic white light interferometry, is easy to generate the problems of limited measurement precision and insufficient robustness, and is difficult to meet the strict requirements of high-precision and full-automatic measurement. Disclosure of Invention In view of the above, the present invention provides a method, a system, a device and a storage medium for automatically correcting a white light interference attitude angle, so as to solve the problem that the conventional white light interference measurement technology cannot effectively solve the stripe change problem caused by the pitch angle deviation of a sample/carrier due to the fact that the attitude angle of the sample/carrier is not corrected, thereby resulting in the problems of limited measurement precision and insufficient robustness. The invention provides a method for automatically correcting a white light interference attitude angle, which is used in a white light interference measurement system comprising a carrier, and comprises the following steps: Obtaining an initial white light interference image obtained by measuring a sample by a white light interference measuring system; resolving the initial white light interference image to obtain at least one group of candidate attitude angles of the sample, wherein each group of candidate attitude angles comprises attitude angle components of the sample in at least two different axial directions; And sequentially judging whether the stripe change information after each adjustment meets the preset change condition or not, and determining the candidate attitude angle corresponding to the stripe change information meeting the preset change condition as a target attitude angle to finish correction. Optionally, each set of candidate pose angles comprises pose angle components of the sample in a lateral direction and in a longitudinal direction; Calculating the initial white light interference image to obtain at least one set of candidate attitude angles of the sample, wherein the method comprises the following steps: Determining a reference point in the initial white light interference image, and respectively acquiring a gray level profile sequence along the transverse direction and the longitudinal direction by taking the reference point as the center; Respectively carrying out effective wave crest detection on the gray level profile sequences in each direction to obtain wave crest detection information corresponding to the gray level profile sequences in each direction; when the wave crest detection informatio