CN-121739878-B - System aberration self-calibration method and device based on double-interference common-path measurement

CN121739878BCN 121739878 BCN121739878 BCN 121739878BCN-121739878-B

Abstract

The invention relates to a system aberration self-calibration method and device based on double-interference common-path measurement, wherein the method comprises the steps of measuring the surface of an optical microstructure to be measured by adopting a double-interference common-path measurement system to obtain phase distribution data and three-dimensional morphology height data, establishing an aberration parameterized model of the double-interference common-path measurement system by taking Zernike polynomials as a basis function, solving an actual aberration coefficient set of the double-interference common-path measurement system in the current measurement state by combining an analysis relation between a laser interference channel and system aberration parameters through inversion of an optimization algorithm by taking the phase distribution data as a basis, reconstructing an aberration field corresponding to the whole measurement field by combining the analysis relation between a white light interference channel and the system aberration parameters, and carrying out point-by-point correction on the three-dimensional morphology height data by utilizing the aberration field. The invention can compensate the inherent aberration of the system on line and with self-reference and high precision.

Inventors

SUN CHENGCHENG
GU PENG
LIU XIANGJUN

Assignees

东华大学

Dates

Publication Date: 20260512
Application Date: 20260226

Claims (10)

1. The system aberration self-calibration method based on double-interference common-path measurement is characterized by comprising the following steps of: The method comprises the steps of measuring the surface of an optical microstructure to be measured by adopting a double-interference common-path measuring system to obtain phase distribution data and three-dimensional morphology height data, wherein the double-interference common-path measuring system comprises a laser interference channel and a white light interference channel, the laser interference channel is used for obtaining the phase distribution data, and the white light interference channel is used for obtaining the three-dimensional morphology height data; Establishing an aberration parameterized model of the double-interference common-path measurement system by taking a Zernike polynomial as a basis function to obtain an analytic relationship between a laser interference channel and system aberration parameters and an analytic relationship between a white light interference channel and system aberration parameters; The phase distribution data is used as a reference, and the analysis relation between the laser interference channel and the system aberration parameter is combined, and the actual aberration coefficient set of the double-interference common-path measurement system in the current measurement state is obtained through inversion of an optimization algorithm; and reconstructing an aberration field corresponding to the whole measurement view field by utilizing the actual aberration coefficient set of the dual-interference common-path measurement system and combining the analysis relation between the white light interference channel and the system aberration parameters, and carrying out point-by-point correction on the three-dimensional morphology height data by utilizing the aberration field.
2. The system aberration self-calibration method based on double-interference common-path measurement according to claim 1, wherein after the double-interference common-path measurement system is adopted to measure the surface of the optical microstructure to be measured to obtain phase distribution data and three-dimensional morphology height data, the method further comprises the step of realizing synchronous mapping of the phase distribution data and the three-dimensional morphology height data through time stamping or spatial registration.
3. The method of self-calibration of systematic aberration based on dual-interference common-path measurement according to claim 1, further comprising preprocessing the phase distribution data, the preprocessing comprising: performing phase unwrapping processing on the phase distribution data; And performing low-order term removal processing on the phase distribution data subjected to the phase unwrapping processing.
4. The system aberration self-calibration method based on double-interference common-path measurement according to claim 1, wherein the analytical relationship between the laser interference channel and the system aberration parameter is expressed as: , wherein, For the phase of the laser light, For the polar coordinates of the measurement point, Is the first laser interference channel The individual Zernike basis functions, Is the first The number of aberration coefficients is chosen, Is the number of Zernike basis functions.
5. The system aberration self-calibration method based on dual-interference common-path measurement according to claim 1, wherein the analytical relationship between the white light interference channel and the system aberration parameter is expressed as: , wherein, Is the three-dimensional shape height data, For the polar coordinates of the measurement point, First of white light interference channel The individual Zernike basis functions, Is the first The number of aberration coefficients is chosen, For the number of Zernike basis functions, Is the laser wavelength.
6. The system aberration self-calibration method based on dual-interference common-path measurement according to claim 1, wherein the step of solving the actual aberration coefficient set of the dual-interference common-path measurement system in the current measurement state by inversion of an optimization algorithm based on the phase distribution data and in combination with an analytic relation between the laser interference channel and the system aberration parameters specifically comprises the following steps: Sorting the phase distribution data into column vectors The value of the Zernike base function corresponding to each measuring point is arranged into a matrix Converting the analytic relation between the laser interference channel and the system aberration parameter into a matrix equation , wherein, Is an aberration coefficient vector to be inverted; based on the matrix equation Constructing an inversion objective function for finding an optimal aberration coefficient vector Minimizing an error between the phase distribution data obtained by the matrix equation and the phase distribution data; solving the inversion objective function by using a least square method as an optimization algorithm to obtain an inverted aberration coefficient vector Is represented by the expression: 。
7. the method for self-calibrating system aberration based on dual-interference common-path measurement according to claim 6, wherein reconstructing an aberration field corresponding to the entire measurement field by combining an analytical relationship between the white light interference channel and system aberration parameters by using an actual aberration coefficient set of the dual-interference common-path measurement system, and performing point-by-point correction on the three-dimensional profile height data by using the aberration field, specifically comprises: vector the aberration coefficient The aberration coefficient of the white light interference channel is substituted into the analytic relation between the white light interference channel and the system aberration parameter to obtain an aberration field ; Calculating an equivalent height error according to the aberration field, wherein the calculating mode is as follows: , wherein, As a result of the equivalent height error, Is the laser wavelength; And carrying out point-by-point correction on the three-dimensional morphology height data by adopting the equivalent height error, wherein the calculation mode during correction is as follows: , wherein, For the corrected three-dimensional topography height data, And (5) the three-dimensional morphology height data.
8. The utility model provides a system aberration self calibration device based on double interference common light path measurement which characterized in that includes: The system comprises a measuring module, a measuring module and a measuring module, wherein the measuring module is used for measuring the surface of an optical microstructure to be measured by adopting a double-interference common-path measuring system to obtain phase distribution data and three-dimensional morphology height data; the establishing module is used for establishing an aberration parameterized model of the double-interference common-path measuring system by taking the Zernike polynomial as a basic function to obtain an analytic relationship between a laser interference channel and a system aberration parameter and an analytic relationship between a white light interference channel and the system aberration parameter; The inversion solving module is used for carrying out inversion solving on an actual aberration coefficient set of the double-interference common-path measuring system in the current measuring state by taking the phase distribution data as a reference and combining an analytic relation between the laser interference channel and the system aberration parameter through an optimization algorithm; And the correction module is used for reconstructing an aberration field corresponding to the whole measurement view field by utilizing the actual aberration coefficient set of the dual-interference common-path measurement system and combining the analysis relation between the white light interference channel and the system aberration parameters, and carrying out point-by-point correction on the three-dimensional morphology height data by utilizing the aberration field.
9. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the processor, when executing the computer program, implements the steps of the system aberration self-calibration method based on dual interference common path measurement according to any one of claims 1-7.
10. A computer readable storage medium having stored thereon a computer program, which when executed by a processor performs the steps of the system aberration self-calibration method based on dual interference common path measurement according to any one of claims 1-7.

Description

System aberration self-calibration method and device based on double-interference common-path measurement Technical Field The invention relates to the field of optical precision measurement and instrument manufacturing, in particular to a system aberration self-calibration method and device based on double-interference common-path measurement. Background Optical interferometry, particularly white light interferometry, has become a core means for ultra-precise optical element surface topography detection due to its advantages of non-contact, high precision and high resolution. Along with the urgent demands of high-end manufacture (such as a photoetching machine and a large-caliber astronomical telescope) on machining-measuring integrated closed-loop manufacture, an interferometry system is directly integrated into machining equipment such as an ultra-precise machine tool, so that on-machine in-situ measurement of workpieces is realized, and the method is a key path for breaking through manufacturing bottlenecks and improving process efficiency and final precision. However, in-situ interferometry poses significant systematic error challenges. The miniaturized, compact interference probe designed to accommodate the limited installation space of machine tools, its optical system can introduce significant aberrations (e.g., spherical aberration, coma, astigmatism, etc.) when measuring high steepness, discontinuous or large off-axis angle optical microstructured surfaces. These systematic aberrations, which are related to the measurement location and surface topography, distort the phase and envelope of the interference signal, resulting in systematic deviations, i.e. "return errors", in the order of more than hundred nanometers, between the surface location detected on the detector and the actual physical location, severely restricting further improvement in the on-machine measurement accuracy. Currently, correction of aberrations for interferometry systems mainly relies on off-line calibration and compensation techniques. And (3) carrying out off-line calibration on the system by adopting a high-precision standard component with known morphology (such as plane, step and sphere) to establish a position-error lookup table or a fitting error model. Although the method is direct, the calibration process is complicated, and the precision, clamping repeatability and difference between the calibration environment and the dynamic working condition of the standard component can introduce additional errors. More importantly, once the measurement system is installed in place on the machine tool, the optical state of the measurement system may drift due to temperature, stress and other factors, and the external calibration cannot realize on-line sensing and compensation of the drift. The analytical compensation method based on the system optical model is to theoretically deduce a system aberration function by accurately modeling an interference light path (comprising a light source, a lens group, a spectroscope, a detector and the like) and correct a measurement result. However, the method is extremely sensitive to the machining and assembly tolerance of the optical element, the real state parameters of the system after the actual integration are difficult to accurately obtain, the model generally cannot cover all nonlinear and environmental coupling effects, and the applicability is limited in the actual complex in-machine environment. The above-mentioned existing methods have a fundamental limitation that they are essentially "open loop" calibrations, i.e. one-time calibration is performed before or outside the measurement, and real-time sensing and closed loop correction of the aberration state of the system itself, which may be time-varying, cannot be performed during the measurement. This results in measurement accuracy that is difficult to continuously ensure during long-term operation or environmental changes. Disclosure of Invention The invention aims to solve the technical problem of providing a system aberration self-calibration method and device based on double-interference common-path measurement, which can invert and compensate inherent aberration of a system on line and with self-reference with high precision. The technical scheme adopted for solving the technical problems is that the invention provides a system aberration self-calibration method based on double-interference common-path measurement, which comprises the following steps: The method comprises the steps of measuring the surface of an optical microstructure to be measured by adopting a double-interference common-path measuring system to obtain phase distribution data and three-dimensional morphology height data, wherein the double-interference common-path measuring system comprises a laser interference channel and a white light interference channel, the laser interference channel is used for obtaining the phase distribution data, and the white lig