Air gap measurement method and device, computer equipment and storage medium

Abstract

The invention relates to an air gap measurement method and device, computer equipment and a storage medium. The method is applied to grazing incidence interference equipment and comprises the following steps: acquiring a first interferogram group of a to-be-detected sample; the first interferogram group comprises at least two first interferograms obtained based on different sample incidence angles; and calculating the air gap thickness of the to-be-measured sample based on the incident sample angle corresponding to each first interferogram and the phase difference between the first interferograms. By adopting the method, the measurement accuracy of the grazing incidence interference equipment can be improved under the non-contact condition.

Description

Technical Field

[0001] The present application relates to the field of measurement technology, and in particular to an air gap measurement method, device, computer equipment and storage medium. Background Art

[0002] In grazing incidence interferometry, when the grazing incidence angle is large, the reference beam and the measurement beam will have obvious deviation in lateral distance, causing shear interference and introducing different degrees of aberration. When the air gap between the large surface of the prism and the sample to be measured changes, the shear amount of the reference beam and the measurement beam will also change, and the reference surface during the corresponding measurement will also change, affecting the accuracy of the interferometer's measurement of the sample's morphology.

[0003] In addition, in the prism-type grazing incidence interferometer, the phase shift ( =2kndcosθ, k=2π / λ) is also related to the thickness of the air gap. In the same tilt angle change, different air gaps correspond to different phase shifts. For example, in the four-step phase shift algorithm, the phase shift of adjacent interference patterns needs to be accurately controlled at pi / 2. If the air gap is large, higher requirements are placed on the resolution of the angle adjustment in the variable tilt interferometer. If the air gap is small, higher requirements are placed on the angle adjustment range in the variable tilt interferometer. Therefore, in the prism-type grazing incidence interferometer, it is particularly important to accurately control the air gap distance between the large surface of the prism and the sample to be tested.

[0004] Traditional technology provides a measurement method for air gap, which is to place a calibration object between the sample to be measured and the large surface of the prism. However, this method is a contact measurement method and can easily cause damage to the sample to be measured. Traditional technology also provides a measurement method using visual recognition with a high-precision camera. However, it is heavily dependent on the accuracy of camera hardware and recognition algorithms, is costly, and has low accuracy.

[0005] Therefore, the prior art still does not provide a non-contact and highly accurate air gap measurement method. Summary of the invention

[0006] Based on this, it is necessary to provide a non-contact air gap measurement method, device, computer equipment and storage medium that can improve the measurement accuracy of grazing incidence interferometer equipment in order to address the above technical problems.

[0007] In a first aspect, this embodiment provides an air gap measurement method, which is applied to a grazing incidence interferometer. The air gap measurement method includes: Acquire a first interference pattern group of the sample to be tested; the first interference pattern group includes at least two first interference patterns obtained based on different incident sample angles; The air gap thickness of the sample to be measured is calculated based on the incident sample angle corresponding to each of the first interference patterns and the phase difference between the first interference patterns.

[0008] In some embodiments, obtaining a first interference pattern set of the sample to be tested includes: Obtaining an initial interference pattern group of the sample to be tested; the initial interference pattern group includes at least two initial interference patterns obtained based on different incident sample angles; Based on the initial interference pattern group of the sample to be tested, determining the light beam phase difference data of the initial interference pattern group; Determine a plurality of incident sample angles corresponding to the preset constant phase difference based on the preset constant phase difference, the beam phase difference data of the initial interference pattern group and the incident sample angle corresponding to each of the initial interference patterns; A first set of interference patterns is obtained based on a plurality of incident sample angles corresponding to the preset constant phase difference.

[0009] In some embodiments, determining the beam phase difference data of the initial interference pattern group based on the initial interference pattern group of the sample to be tested includes: Calculating the phase difference between each of the initial interference patterns and the first initial interference pattern in sequence to obtain an initial phase difference of each of the initial interference patterns; Based on the initial phase differences of the multiple initial interference patterns, the beam phase difference data of the initial interference pattern group is obtained.

[0010] In some embodiments, determining a plurality of incident sample angles corresponding to the preset constant phase difference based on the preset constant phase difference and the beam phase difference data of the initial interference pattern group comprises: Determining the mapping relationship between the incident sample angle and the phase difference based on the beam phase difference data of the initial interference pattern group; Based on the preset constant phase difference and the mapping relationship, a plurality of incident sample angles corresponding to the preset constant phase difference are determined.

[0011] In some embodiments, the air gap measurement method further includes: Based on the prism incident angle corresponding to each of the first interference patterns, respectively determine the optical path angle information of each of the first interference patterns; the optical path angle information includes the prism incident angle, the first refraction angle, the first incident angle and the incident sample angle; the prism includes a right-angle surface and an inclined surface; The air gap thickness of the sample to be measured is calculated based on the optical path angle information corresponding to each of the first interference patterns and the phase difference between the first interference patterns.

[0012] In some embodiments, determining the optical path angle information of each first interference pattern based on the prism incident angle corresponding to each first interference pattern includes: Determining a first refraction angle based on the prism incident angle, the air refractive index, and the prism refractive index; Determining a first incident angle based on a geometric relationship between the first refraction angle and the first incident angle; Based on the first incident angle, the air refractive index and the prism refractive index, an incident sample angle is determined.

[0013] In some embodiments, the step of calculating the air gap thickness of the sample to be tested based on the optical path angle information corresponding to each of the first interference patterns and the phase difference between the first interference patterns includes: Combining any first interference pattern with the remaining first interference patterns in pairs in sequence to obtain a plurality of first sub-interference pattern groups; Calculating the air gap thickness of each first sub-interference pattern group based on the incident sample angle of the first interference pattern in each first sub-interference pattern group, the phase difference of the first interference pattern group, and the laser wavelength of the grazing incidence interferometer device; The air gap thickness of the sample to be tested is determined based on the air gap thicknesses of the plurality of first sub-interference pattern groups.

[0014] In some embodiments, the step of calculating the air gap thickness of the sample to be tested based on the optical path angle information corresponding to each of the first interference patterns and the phase difference between the first interference patterns further includes: Combining any first interference pattern with the remaining first interference patterns in pairs in sequence to obtain a plurality of first sub-interference pattern groups; Calculating the incident sample angle derivative of each of the first sub-interference pattern groups in turn; Calculating the phase difference of each of the first sub-interference pattern groups based on the optical path angle information, the incident sample angle deflection and the laser wavelength of the grazing incidence interferometer; Calculating the air gap thickness of each of the first sub-interference pattern groups based on the optical path angle information of each of the first sub-interference pattern groups, the laser wavelength of the grazing incidence interferometer device, and the phase difference of the first sub-interference pattern group; The air gap thickness of the sample to be tested is determined based on the air gap thicknesses of the plurality of first sub-interference pattern groups.

[0015] In some embodiments, determining the air gap thickness of the sample to be tested based on the air gap thicknesses of the plurality of first sub-interference pattern groups comprises: The air gap thickness of the sample to be tested is obtained by calculating an average value based on the air gap thicknesses of the plurality of first sub-interference pattern groups.

[0016] In a second aspect, this embodiment provides an air gap measurement device, which is applied to a grazing incidence interferometer. The air gap measurement device includes: A pattern group acquisition module, used to acquire a first interference pattern group of the sample to be tested; the first interference pattern group includes at least two first interference patterns obtained based on different incident sample angles; The thickness calculation module is used to calculate the air gap thickness of the sample to be measured based on the incident sample angle corresponding to each of the first interference patterns and the phase difference between the first interference patterns.

[0017] In a third aspect, this embodiment provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor implements the above-mentioned method when executing the computer program.

[0018] The above-mentioned air gap measurement method, device, computer equipment and storage medium obtain a first interference pattern group of the sample to be measured; the first interference pattern group includes at least two first interference patterns obtained based on different incident sample angles; based on the incident sample angle corresponding to each of the first interference patterns and the phase difference between the first interference patterns, the air gap thickness of the sample to be measured is calculated. The air gap thickness can be calculated by obtaining at least two first interference patterns obtained based on different incident sample angles taken by a grazing incidence interferometer, combining the incident sample angle and the phase difference, thereby accurately obtaining the air gap thickness in a non-contact situation, which helps the grazing incidence interferometer to more accurately detect the fine structure of the surface of the sample to be measured, thereby achieving the effect of improving the measurement accuracy of the grazing incidence interferometer. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is an application environment diagram of an air gap measurement method in one embodiment; Figure 2 Schematic diagram of a flow chart of an air gap measurement method in one embodiment; Figure 3 is a structural block diagram of a grazing incidence interferometer in one embodiment; Figure 4 A schematic diagram of the angles of light passing through a prism and a sample to be tested in one embodiment; Figure 5 A schematic diagram of a process for obtaining facial distribution in one embodiment; Figure 6 A schematic diagram of an interference pattern and a phase under the adjustment of the incident angle of a prism with a medium step length in one embodiment; Figure 7 A schematic diagram of the incident angle and phase when the incident angle of the prism is adjusted in a medium-step length in one embodiment; Figure 8A schematic diagram of interference patterns and phases at different incident angles with a constant phase difference in one embodiment; Fig. 9 is a structural block diagram of an air gap measurement device in one embodiment; Fig.10 FIG. 4 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0021] The air gap measurement method provided in the embodiment of the present application can be applied to Figure 1 In the application environment shown. Among them, the terminal 102 communicates with the grazing incidence interferometer 104 through the network. The data storage system can store the data that the grazing incidence interferometer 104 needs to process. The data storage system can be integrated on the grazing incidence interferometer 104, or it can be placed on the cloud or other network servers. The terminal 102 obtains a first interference pattern group of the sample to be tested by communicating with the grazing incidence interferometer 104; the first interference pattern group includes at least two first interference patterns obtained based on different incident sample angles; based on the incident sample angle corresponding to each of the first interference patterns and the phase difference between the first interference patterns, the air gap thickness of the sample to be tested is calculated, and the calculated air gap thickness is fed back to the grazing incidence interferometer 104. Among them, the terminal 102 can be, but is not limited to, various personal computers, laptops, smart phones, tablet computers and portable wearable devices, and the portable wearable device can be a head-mounted device, etc.

[0022] In one embodiment, Figure 2 As shown, an air gap measurement method is provided, which is applied to a grazing incidence interferometer. Figure 1 The terminal 102 in the example is used as an example to illustrate, and the following steps are included: Step S100, obtaining a first interference pattern group of the sample to be tested.

[0023] The sample to be measured may be a sample that needs to be measured on the surface by a grazing incidence interferometer. The first interference pattern group may be a group of interference images collected by a grazing incidence interferometer at different incident angles. Furthermore, the first interference pattern group includes at least two first interference patterns obtained based on different incident sample angles. The incident sample angle may be an angle starting from a prism and incident on the sample to be measured.

[0024] It is understandable that in order to obtain enough information to reconstruct the three-dimensional morphology of the sample surface, it is necessary to capture the interference pattern of the sample to be tested at multiple different incident angles. By adjusting the incident sample angle, the light can be irradiated to the sample to be tested from different angles to obtain multiple first interference patterns. By changing the incident angle, and then changing the incident sample angle, different grazing incidence angles can be created, thereby recording different interference fringes, and thus capturing the interference pattern changes caused by the air gap.

[0025] Step S200, calculating the air gap thickness of the sample to be measured based on the incident sample angle corresponding to each of the first interference patterns and the phase difference between the first interference patterns.

[0026] The phase difference may be a light beam phase change between two adjacent first interference patterns.

[0027] Exemplarily, the thickness can be calculated based on the adjacent first interference patterns, or any first interference pattern can be selected as the reference interference pattern, and the remaining first interference patterns and the reference interference pattern are used to calculate the thickness. Further, the first interference pattern can be first phase extracted, for example, the phase difference can be extracted by Fourier transform, Hilbert transform and other methods. Further, the interference pattern can be converted into digital form, and the phase shift algorithm is used to solve the phase value on each pixel. It is understandable that according to the variation law of the interference fringes, the phase difference when the light passes through different paths can be determined by analyzing the phase distribution. For grazing incidence, the presence of an air gap will cause additional optical path difference, which in turn affects the position of the interference fringes. Therefore, the relationship between the phase difference and the air gap thickness can be constructed in combination with the wavelength of the light source and the incident sample angle, so as to calculate the air gap thickness between the prism and the sample to be measured.

[0028] Exemplarily, the air gap thickness of the sample to be tested can be calculated by fitting according to the set air gap thickness, the incident sample angle and the phase difference between adjacent first interference patterns. When the image similarity between the fitting result and the multiple first interference patterns is higher than a threshold, the air gap thickness can be considered to be the air gap thickness of the sample to be tested.

[0029] Exemplarily, the air gap thickness of the sample to be tested can be calculated by constructing training data through the incident sample angle, phase difference, and corresponding air gap of the historical interference pattern group, and training the neural network based on the training data to obtain a thickness prediction model, so that the air gap thickness of the sample to be tested can be calculated through the thickness prediction model.

[0030] The present embodiment provides an air gap measurement method, which obtains a first interference pattern group of a sample to be measured; the first interference pattern group includes at least two first interference patterns obtained based on different incident sample angles; based on the incident sample angle corresponding to each of the first interference patterns and the phase difference between the first interference patterns, the air gap thickness of the sample to be measured is calculated. The air gap thickness can be calculated by obtaining at least two first interference patterns obtained based on different incident sample angles taken by a grazing incidence interferometer, and combining the incident sample angle and the phase difference, so as to accurately obtain the air gap thickness in a non-contact situation, which helps the grazing incidence interferometer to more accurately detect the fine structure of the surface of the sample to be measured, thereby achieving the effect of improving the measurement accuracy of the grazing incidence interferometer.

[0031] In some embodiments, obtaining a first interference pattern set of the sample to be tested includes: Obtaining an initial interference pattern group of the sample to be tested; the initial interference pattern group includes at least two initial interference patterns obtained based on different incident sample angles; Based on the initial interference pattern group of the sample to be tested, determining the light beam phase difference data of the initial interference pattern group; Determine a plurality of incident sample angles corresponding to the preset constant phase difference based on the preset constant phase difference, the beam phase difference data of the initial interference pattern group and the incident sample angle corresponding to each of the initial interference patterns; A first set of interference patterns is obtained based on a plurality of incident sample angles corresponding to the preset constant phase difference.

[0032] The initial interference pattern group includes at least two initial interference patterns obtained based on different incident sample angles. In conventional techniques, interference images can be obtained by adjusting the phase shifting structure in equal steps, thereby adjusting the incident sample angle for the sample to be measured, and obtaining multiple interference images. However, adjusting in equal steps may not achieve the effect of keeping the phase difference between adjacent interference patterns consistent, thereby causing the problem of reduced measurement accuracy.

[0033] In this embodiment, the incident sample angle may be adjusted in accordance with the preset step size to obtain an initial interference pattern group of the sample to be tested. The step size may be the change in the incident angle, and the preset step size may be a constant step size, or may be set differently according to the phase change law or other factors. Based on the initial interference pattern group of the sample to be tested, the beam phase difference data of the initial interference pattern group is determined, and the initial interference pattern group may be solved by a phase extraction algorithm to obtain the beam phase difference data. The beam phase difference data may include the phase information of each initial interference pattern, and further, may also include the phase difference value of each pair of adjacent interference patterns, or the phase difference value between each initial interference pattern and the first initial interference pattern.

[0034] The preset constant phase difference may be a pre-set fixed phase difference, which is used to adjust the incident sample angle so that in the first interference pattern group recorded after adjusting the incident sample angle, the phase differences of adjacent interference patterns all satisfy the preset constant phase difference. The preset constant phase difference may be determined based on prior knowledge.

[0035] Based on the preset constant phase difference, the beam phase difference data of the initial interference pattern group and the incident sample angle corresponding to each of the initial interference patterns, a plurality of incident sample angles corresponding to the preset constant phase difference are determined. This may be by judging whether the phase difference value between each pair of adjacent interference patterns satisfies the preset constant phase difference, that is, whether the difference between the phase difference value and the preset constant phase difference is within the error range. If not, the incident sample angle corresponding to the adjacent interference pattern needs to be adjusted. It may also be by determining the variation law of the phase with the incident sample angle through the beam phase difference data, thereby determining a plurality of incident sample angles that should be taken when the phase difference is fixed to the preset constant phase difference.

[0036] The first interference pattern group is obtained based on multiple incident sample angles corresponding to the preset constant phase difference. The first interference pattern group can be obtained by acquiring a first interference pattern corresponding to each incident sample angle through multiple incident sample angles.

[0037] The present embodiment provides an air gap measurement method, which determines multiple incident sample angles corresponding to the preset constant phase difference based on the preset constant phase difference, the beam phase difference data of the initial interference pattern group and the incident sample angle corresponding to each of the initial interference patterns, and obtains the first interference pattern group recorded after adjusting the incident sample angle. The experimental conditions can be controlled more finely, thereby optimizing the quality of the interference fringes, improving the consistency and accuracy of the air gap thickness calculation, and achieving the effect of improving the measurement accuracy of the grazing incidence interferometer equipment.

[0038] In some embodiments, determining the beam phase difference data of the initial interference pattern group based on the initial interference pattern group of the sample to be tested includes: Based on a preset phase calibration algorithm, the phase difference between each of the initial interference patterns and the first initial interference pattern is calculated in sequence to obtain an initial phase difference of each of the initial interference patterns; Based on the initial phase differences of the multiple initial interference patterns, the beam phase difference data of the initial interference pattern group is obtained.

[0039] Among them, the preset phase calibration algorithm is used to extract and calculate the phase information from the interference pattern. The existing phase calibration algorithm can be used to calculate the phase difference between each initial interference pattern and the first initial interference pattern. Exemplarily, Fourier transform, Hilbert transform, four-step phase shift method and other phase shift algorithms can be used, which are not limited in this embodiment.

[0040] The initial phase difference may be obtained by taking the first initial interference pattern as a reference interference pattern and calculating a phase difference value of each initial interference pattern relative to the first initial interference pattern.

[0041] The beam phase difference data may be a collection of initial phase differences of multiple initial interference patterns. Based on the initial phase differences of multiple initial interference patterns, the beam phase difference data of the initial interference pattern group is obtained, all initial phase differences can be summarized, and the variation law of the interference pattern under different incident conditions can be described.

[0042] The present embodiment provides an air gap measurement method, which calculates the phase difference between each of the initial interference patterns and the first initial interference pattern in sequence based on a preset phase calibration algorithm, and then obtains the light beam phase difference data of the initial interference pattern group. This method can more accurately describe the variation law of the interference pattern under different incident conditions, so as to achieve more accurate adjustment of the incident sample angle, thereby achieving the effect of improving the measurement accuracy of the grazing incidence interferometer equipment.

[0043] In some embodiments, determining a plurality of incident sample angles corresponding to the preset constant phase difference based on the preset constant phase difference and the beam phase difference data of the initial interference pattern group comprises: Determine the mapping relationship between the incident sample angle and the phase difference based on a linear regression algorithm and the beam phase difference data of the initial interference pattern group; Based on the preset constant phase difference and the mapping relationship, a plurality of incident sample angles corresponding to the preset constant phase difference are determined.

[0044] Wherein, based on the beam phase difference data of the initial interference pattern group, the mapping relationship between the incident sample angle and the phase difference is determined, and it can be that the beam phase difference data of the initial interference pattern group is fitted by using algorithms such as linear regression. Exemplarily, according to the incident sample angle of each initial interference pattern and the phase difference between adjacent interference patterns, the corresponding relationship between multiple groups of incident sample angles and phase differences can be obtained, and the mapping relationship between the incident sample angle and the phase difference can be obtained by fitting.

[0045] Furthermore, based on the preset constant phase difference and the mapping relationship, a plurality of incident sample angles corresponding to the preset constant phase difference are determined by querying the mapping relationship so that the phase difference corresponding to each pair of adjacent incident sample angles is the preset constant phase difference.

[0046] The angle of the incident sample can be adjusted by adjusting the angle of the light source or the angle of the phase shifting structure between the light source and the sample.

[0047] The present embodiment provides an air gap measurement method, which determines the mapping relationship between the incident sample angle and the phase difference, and then determines multiple incident sample angles corresponding to the preset constant phase difference, so that the phase difference of all adjacent first interference patterns is close to or reaches the preset constant phase difference, thereby enhancing the accuracy of air gap thickness calculation. Furthermore, it can also help optimize the quality of interference fringes, improve the overall performance of interference measurement, and achieve the effect of improving the measurement accuracy of grazing incidence interferometry equipment.

[0048] In some embodiments, the air gap measurement method further comprises: Based on the prism incident angle corresponding to each of the first interference patterns, respectively determine the optical path angle information of each of the first interference patterns; the optical path angle information includes the prism incident angle, the first refraction angle, the first incident angle and the incident sample angle; the prism includes a right-angle surface and an inclined surface; The air gap thickness of the sample to be measured is calculated based on the optical path angle information corresponding to each of the first interference patterns and the phase difference between the first interference patterns.

[0049] The optical path angle information includes the angle of the light relative to the prism medium surface during the process from incident to emitted, and the prism medium surface includes a right-angle surface and an inclined surface. The optical path can be the light propagation path formed during the process from the light source incident to the prism surface to the light emitting from the prism surface. Further, the optical path angle information can include the angle of the light path relative to the prism surface, and can also include the angle of the light path relative to the internal medium surface of the prism. Further, the prism surface can be a right-angle surface, and the internal medium surface of the prism can be an inclined surface.

[0050] In some embodiments, based on the prism incident angle corresponding to each of the first interference patterns, respectively determining the optical path angle information of each of the first interference patterns includes: Determining a first refraction angle based on the prism incident angle, the air refractive index, and the prism refractive index; Determining a first incident angle based on a geometric relationship between the first refraction angle and the first incident angle; Based on the first incident angle, the air refractive index and the prism refractive index, an incident sample angle is determined.

[0051] Among them, the optical path angle information can include the prism incident angle, the first refraction angle, the first incident angle and the incident sample angle respectively. The prism incident angle can be the angle of the light relative to the normal of the prism surface when the light enters the prism surface from the air, and can also be called the incident prism right-angle surface angle. The first refraction angle can be the angle of the light relative to the normal inside the sample after the light is refracted on the prism surface, and can also be called the right-angle surface refraction angle. The first incident angle can be the inclination angle of the light relative to the prism surface when the light enters the prism surface from the air, and can also be called the incident prism hypotenuse angle. The incident sample angle in this embodiment can be the actual inclination angle of the light relative to the prism surface when the light emerges from the inside of the prism into the air, and can also be called the exit prism right-angle surface angle. In this embodiment, the actual incident sample angle value can be determined by converting the prism incident angle, and then further calculations can be performed.

[0052] Based on the prism incident angle, air refractive index and prism refractive index, the first refraction angle is determined. It can be understood that the prism incident angle and the first refraction angle are affected by the air refractive index and the prism refractive index. When the prism incident angle, air refractive index and prism refractive index are known, the first refraction angle can be converted.

[0053] In a prism, light propagates in the prism through a first refraction angle. The optical path of the light in the prism can be determined based on the geometric structure of the prism. Correspondingly, the first incident angle corresponding to the first refraction angle can be determined based on the collective relationship.

[0054] Furthermore, when the light is emitted from the sample and returns to the air, the light is transmitted from the prism to the air, and a first incident angle is obtained. Furthermore, the first incident angle can be converted according to the first incident angle, the refractive index of air and the refractive index of the prism.

[0055] The present embodiment provides an air gap measurement method, which obtains the optical path angle information by a single calculation based on the prism incident angle, and can accurately determine the incident and exit characteristics of the light on the sample surface, as well as the actual value of the incident sample angle, thereby improving the accuracy of the air gap thickness measurement and achieving the effect of improving the measurement accuracy of the grazing incidence interferometer equipment.

[0056] In some embodiments, the step of calculating the air gap thickness of the sample to be tested based on the optical path angle information corresponding to each of the first interference patterns and the phase difference between the first interference patterns further includes: Combining any first interference pattern with the remaining first interference patterns in pairs in sequence to obtain a plurality of first sub-interference pattern groups; Calculating the incident sample angle derivative of each of the first sub-interference pattern groups in turn; Calculating a third phase difference of each of the first sub-interference pattern groups based on the optical path angle information, the incident sample angle deflection, and the laser wavelength of the grazing incidence interferometer; Calculating the air gap thickness of each of the first sub-interference pattern groups based on the optical path angle information of each of the first sub-interference pattern groups, the laser wavelength of the grazing incidence interferometer device, and the phase difference of the first sub-interference pattern group; The air gap thickness of the sample to be tested is determined based on the air gap thicknesses of the plurality of first sub-interference pattern groups.

[0057] Wherein, the air gap thickness of the sample to be tested is calculated by grouping a plurality of first interference patterns to obtain a plurality of first sub-interference pattern groups. Any first interference pattern is sequentially combined with each of the remaining first interference patterns in pairs. In a specific embodiment, the first first interference pattern is sequentially combined with each of the remaining first interference patterns in the first interference pattern group in pairs to obtain a plurality of first sub-interference pattern groups.

[0058] Calculating the incident sample angle derivative of each of the first sub-interference pattern groups in sequence may be calculating the difference in the incident sample angle between two first interference patterns in each of the first sub-interference pattern groups.

[0059] Furthermore, the incident sample angle derivative can be obtained by converting the prism incident angle derivative into the first refraction angle difference and the first incident angle derivative in sequence.

[0060] The phase difference of each of the first sub-interference pattern groups is calculated based on the optical path angle information, the incident sample angle derivative and the laser wavelength of the grazing incidence interferometer device. The phase difference of each of the first sub-interference pattern groups can be calculated based on the incident sample angle in the optical path angle information, combined with the incident sample angle derivative and the laser wavelength of the grazing incidence interferometer device.

[0061] In a specific embodiment, the calculation formula of the phase difference of the first sub-interference pattern group is as follows:

[0062] Among them, Δ is the phase difference of the first sub-interference pattern group, λ is the laser wavelength of the grazing incidence interferometer, θ4 is the incident sample angle of the first interferogram as a reference, and Δθ4 is the incident sample angle derivative.

[0063] Furthermore, based on the optical path angle information of each first sub-interference pattern group, the laser wavelength of the grazing incidence interference device and the phase difference of the first sub-interference pattern group, the air gap thickness of each first sub-interference pattern group is calculated. The air gap thickness of each first sub-interference pattern group can be calculated based on the prism incident angle, the first refraction angle, the first incident angle and the incident sample angle of one first interference pattern in the first sub-interference pattern group, the prism incident angle of another first interference pattern, the laser wavelength, and the phase difference of the first sub-interference pattern group.

[0064] In a specific embodiment, the calculation formula of the air gap thickness corresponding to each first sub-interference pattern group is as follows:

[0065] Wherein, d is the thickness of the air gap, λ is the laser wavelength of the grazing incidence interferometer, θ1 is the prism incident angle of the first first interference pattern in the group, θ2 is the first refraction angle of the first first interference pattern in the group, θ3 is the first incident angle of the first first interference pattern, θ4 is the incident sample angle of the first first interference pattern in the group, θ1' is the prism incident angle of the other first interference pattern in the group, Δ is the phase difference of the first sub-interference pattern group.

[0066] The air gap thickness of the sample to be tested is determined based on the air gap thicknesses of the multiple first sub-interference pattern groups. The air gap thickness of the sample to be tested can be obtained by taking the average, weighted average or other statistical methods based on the air gap thicknesses calculated based on the multiple first sub-interference pattern groups.

[0067] The present embodiment provides an air gap measurement method, which calculates the phase difference of each of the first sub-interference pattern groups according to the optical path angle information, the incident sample angle derivative and the laser wavelength of the grazing incidence interferometer device, and then calculates the air gap thickness of each of the first sub-interference pattern groups according to the optical path angle information of each of the first sub-interference pattern groups, the laser wavelength of the grazing incidence interferometer device and the phase difference of the first sub-interference pattern group. The partial derivative calculation of the air gap thickness can be realized, the measurement accuracy can be improved, and the robustness and consistency of the measurement results can be enhanced, thereby achieving the effect of improving the measurement accuracy of the grazing incidence interferometer device.

[0068] In some embodiments, the step of calculating the air gap thickness of the sample to be measured based on the incident sample angle corresponding to each of the first interference patterns and the phase difference between the first interference patterns comprises: Combining any first interference pattern with the remaining first interference patterns in pairs in sequence to obtain a plurality of first sub-interference pattern groups; The air gap thickness of the sample to be tested is calculated by grouping a plurality of first interference patterns to obtain a plurality of first sub-interference pattern groups. Any first interference pattern is sequentially combined with each of the remaining first interference patterns in pairs. In a specific embodiment, the first first interference pattern is sequentially combined with each of the remaining first interference patterns in the first interference pattern group in pairs to obtain a plurality of first sub-interference pattern groups.

[0069] Calculate the air gap thickness of each first sub-interference pattern group based on the incident sample angle of the first interference pattern in each first sub-interference pattern group, the phase difference between the first interference pattern group and the first first interference pattern, and the laser wavelength of the grazing incidence interferometer; The air gap thickness of the sample to be tested is determined based on the air gap thicknesses of the plurality of first sub-interference pattern groups.

[0070] In this embodiment, the air gap thickness can be obtained based on forward calculation. Further, based on the incident sample angle of the first interference pattern in each first sub-interference pattern group, the phase difference between the first interference pattern and the first first interference pattern, and the laser wavelength of the grazing incidence interference device, the air gap thickness of each first sub-interference pattern group is calculated, which can be calculated based on the laser wavelength, the phase difference, and the cosine value of the incident sample angle of the two first interference patterns.

[0071] For example, assuming that the first sub-interference pattern group includes the first first interference pattern A, and the second first interference pattern B, the cosine value of the incident sample angle of A is cos(θ A ), the cosine of the incident sample angle of B is cos(θ B ), the difference in the cosine value of the incident sample angle of the first sub-interference pattern group can be calculated, that is, cos(θ B )-cos(θ A ), the air gap thickness is calculated based on the laser wavelength and the ratio of the phase difference to the cosine value.

[0072] In a specific embodiment, the calculation formula of the air gap thickness is:

[0073] Where d is the air gap thickness, λ is the laser wavelength of the grazing incidence interferometer, 0 is the phase difference between the two first interference patterns in the first sub-interference pattern group, θ4 is the incident sample angle of the first first interference pattern, and θ4' is the incident sample angle of the other first interference pattern in the first sub-interference pattern group.

[0074] The air gap thickness of the sample to be tested is determined based on the air gap thicknesses of the multiple first sub-interference pattern groups. The air gap thickness of the sample to be tested can be obtained by taking the average, weighted average or other statistical methods based on the air gap thicknesses calculated based on the multiple first sub-interference pattern groups.

[0075] The present embodiment provides an air gap measurement method, which can improve the measurement accuracy and enhance the robustness and consistency of the measurement results by calculating the air gap thickness of each first sub-interference pattern group based on the incident sample angle of the first interference pattern in each first sub-interference pattern group, the phase difference between each first interference pattern group, and the laser wavelength of the grazing incidence interferometer device, thereby achieving the effect of improving the measurement accuracy of the grazing incidence interferometer device.

[0076] In some embodiments, determining the air gap thickness of the sample to be tested based on the air gap thicknesses of the plurality of first sub-interference pattern groups comprises: The air gap thickness of the sample to be tested is obtained by calculating an average value based on the air gap thicknesses of the plurality of first sub-interference pattern groups.

[0077] In a specific embodiment, the average value is calculated as follows:

[0078] Among them, d avg is the average air gap thickness, N is the number of first interference patterns, d i is the air gap thickness under the Nth first interference pattern.

[0079] An air gap measurement method provided in this embodiment can calculate the average value of the air gaps in multiple first interference patterns, thereby further improving the accuracy of air gap calculation, enhancing the robustness and consistency of measurement results, and achieving the effect of improving the measurement accuracy of grazing incidence interferometer equipment.

[0080] In order to more clearly illustrate the technical solution of the present application, the present application also provides a detailed embodiment.

[0081] In one embodiment, an air gap measurement method is provided, which is applied to a grazing incidence interferometer, and further applied to a prism-type grazing incidence interferometer, wherein: like Figure 3As shown, the prism-type grazing incidence interferometer includes a laser light source 1, a beam expander 2, a phase shifting structure 3, a collimating objective lens 4, a sample to be measured 5, a right-angle prism 6, a projection screen 7, and a CCD camera 8. The collimated light beam emitted by the laser light source 1 is expanded by the beam expander 2, then reflected by the reflector in the phase shifting structure 3, and enters the collimating objective lens 4 for light beam collimation, wherein the distance between the beam expander 2 and the collimating objective lens 4 is the sum of the focal lengths of the two lenses, and the beam expander 2 and the collimating objective lens 4 complete the expansion of the light beam emitted by the laser light source, so that the light beam enters the first right-angle surface of the right-angle prism 6 as parallel light, and at the large surface of the prism, the reflected light beam is used as a reference light beam and is emitted from the second right-angle surface of the right-angle prism 6; after the transmitted light beam is reflected by the surface of the sample to be measured 5, the measuring light beam carrying the surface shape information of the sample to be measured returns to the large surface of the right-angle prism 6, and after being emitted from the second right-angle surface of the right-angle prism 6, it interferes with the reference light beam and is received by the projection screen 7, and the interference data is recorded and saved by the CCD camera 8, and an interference pattern group with a known phase difference is obtained through a phase calibration algorithm, and a phase distribution is obtained through a phase shift algorithm, and then through beam conversion, it is multiplied by an optical path factor, and then the surface shape distribution data of the sample to be measured is obtained.

[0082] In this embodiment, the air gap measurement method includes: In order to ensure that the phase difference of the input interference pattern group is constant and to ensure the stability of the output result of the phase shift algorithm, the phase difference between each interference pattern and the first interference pattern can be obtained through the phase calibration algorithm, and the phase shift structure can be adjusted through mathematical processing such as difference to achieve the change of the prism incident angle to obtain a constant phase difference. 0 interference pattern group.

[0083] Specifically, the air gap can be ensured before calculating the distribution of the surface type to be measured by the phase shift algorithm, that is, the air gap between the large surface (inclined surface) of the prism and the sample to be measured is at a preset position d0.

[0084] like Figure 5 As shown, the steps to obtain the facial distribution are as follows: Step S301, obtain the phase difference of multiple discrete interference patterns when the prism incident angle is changed in equal steps: by using the phase calibration algorithm, the prism incident angle θ1 is changed in equal steps to obtain the phase difference of N discrete interference patterns, such as Figure 6 and Figure 7 As shown. Figure 6 In the figure, the x-axis is the number of the interference pattern, including 1 to N interference patterns, and the phase As the vertical axis, we can see the phase change curve when the prism incident angle θ1 is changed in equal steps. Figure 7 In the figure, the incident angle of the prism is taken as the x-axis, which includes θ1 1 to θ1 N+1 Multiple prism incident angles, with phase As the ordinate, when the angle difference between the incident angles of adjacent prisms is constant, it can be seen that the phase It has a linear relationship with cosθ and a nonlinear relationship with θ.

[0085] Step S302, based on the phase difference of multiple discrete interference patterns, fit the mapping relationship between the prism incident angle and the phase difference, and determine multiple prism incident angles under a constant phase difference according to the mapping relationship: obtain the relationship between the phase difference and the prism incident angle θ1 of the interference pattern sequence 1-N through mathematical processing methods such as linear regression, and then recalculate the phase shifter position, thereby adjusting the prism incident angle θ1 to obtain the phase difference Δ A constant set of interference patterns, such as Figure 8 As shown. Figure 8 By fitting the relationship between phase and prism incident angle, it can be determined that the phase difference Δ When the value is constant, the prism incident angle corresponding to each interference pattern.

[0086] Step S303, based on the phase difference between each two interference patterns and the prism incident angle, calculate the air gap thickness under the two interference patterns. , θ1 and θ1' to calculate the current air gap thickness d, and compare it with the preset position d0, and input Δd to the stage unit carrying the sample to be tested, where Δd=d-d0.

[0087] Step S304, after completing the height adjustment, re-calibrate the phase, obtain the interference pattern group with a constant phase difference, and then obtain the surface distribution of the sample to be tested through a phase shift algorithm.

[0088] This embodiment does not specifically limit the specific phase shift algorithm used by the interferometer, and the corresponding constant phase difference can be determined according to the phase difference required by the adopted phase shift algorithm. For example, a three-step phase shift, a four-step phase shift, a five-step phase shift, etc. phase shift algorithm can be used. This embodiment does not specifically limit the phase calibration algorithm used. For example, in the ideal interference pattern group, the light intensity change curve I (x0, y0) at a certain position in the interference pattern group is recorded, and the phase change period is calculated through Fourier transformation, and the phase shift setting of the phase shifter is readjusted to ensure that the phase of adjacent interference patterns is constant.

[0089] It is known that the prism incident angle corresponding to the first interference pattern is θ1, the first refraction angle is θ2, the first incident angle is θ3, and the incident sample angle is θ4, recorded as the grazing incidence angle. The refractive indices of air and prism are n1 and n2 respectively, as shown in Figure 4 As shown, From the law of refraction we know that:

[0090]

[0091] And from the geometric relationship, we can know:

[0092] Thus, the prism incident angle θ1, the first refraction angle θ2, the first incident angle θ3, and the incident sample angle θ4 of each interference pattern can be obtained.

[0093] Taking the first and second interference patterns as examples, it is known that the prism incident angle corresponding to the first interference pattern is θ1, and the corresponding grazing incidence angle is θ4; the prism incident angle of the second interference pattern is θ1', and the corresponding grazing incidence angle is θ4'. The phase difference between the first interference pattern and the second interference pattern is 0, the air gap thickness, i.e. the interference cavity thickness, can be calculated based on the forward and partial derivative methods.

[0094] Among them, in the forward calculation, the air gap thickness is:

[0095] In the partial derivative calculation, we can first calculate the partial derivative Δθ1 of the right-angle side of the incident prism of the two interference patterns based on the prism incident angle θ1 corresponding to the first interference pattern and the prism incident angle θ1' corresponding to the second interference pattern:

[0096] After obtaining the right-angle side derivative Δθ1 of the incident prism of the two interference patterns, the first refraction angle derivative Δθ2 is calculated according to the right-angle side derivative Δθ1 of the incident prism, the prism incident angle θ1 corresponding to the first interference pattern, the first refraction angle θ2 and the prism refractive index n2:

[0097] After calculating the first refraction angle difference Δθ2, the incident prism hypotenuse guide Δθ3 can be obtained according to the first refraction angle difference Δθ2:

[0098] According to the first incident angle θ3 of the first interference pattern and the incident sample angle θ4, as well as the prism refractive index n2 and the incident prism hypotenuse derivative Δθ3, the incident sample angle derivative Δθ4 can be obtained:

[0099] Furthermore, according to the laser wavelength λ of the grazing incidence interferometer, the incident sample angle θ4 of the first interference pattern, and the incident sample angle derivative Δθ4, the phase difference Δ :

[0100] From this, the air gap thickness d is calculated as follows:

[0101] Furthermore, the accuracy of the calculation can be improved by performing numerical operations such as averaging the air gap thickness calculated from multiple interference patterns in the interference pattern group:

[0102] Where N is the number of interference patterns, d avg is the air gap thickness of the sample to be tested, d i is the air gap thickness of the i-th interference pattern.

[0103] The present embodiment provides an air gap measurement method, which obtains a first interference pattern group of a sample to be measured; the first interference pattern group includes at least two first interference patterns obtained based on different incident sample angles; based on the incident sample angle corresponding to each of the first interference patterns and the phase difference between the first interference patterns, the air gap thickness of the sample to be measured is calculated. The air gap thickness can be calculated by obtaining at least two first interference patterns obtained based on different incident sample angles taken by a grazing incidence interferometer, and combining the incident sample angle and the phase difference, so as to accurately obtain the air gap thickness in a non-contact situation, which helps the grazing incidence interferometer to more accurately detect the fine structure of the surface of the sample to be measured, thereby improving the grazing incidence interferometer. The effect of improving the measurement accuracy of the device; by determining multiple incident sample angles corresponding to the preset constant phase difference based on the preset constant phase difference and the beam phase difference data of the initial interference pattern group, and obtaining the first interference pattern group recorded after adjusting the incident sample angle, the experimental conditions can be controlled more finely, thereby optimizing the quality of the interference fringes, improving the consistency and accuracy of the air gap thickness calculation, and achieving the effect of improving the measurement accuracy of the grazing incidence interferometer device; by calculating the phase difference between each of the initial interference patterns and the first initial interference pattern in turn based on the preset phase calibration algorithm, and then obtaining the beam phase difference data of the initial interference pattern group, the variation law of the interference pattern under different incident conditions can be more accurately described, so as to achieve more accurate The accurate incident sample angle adjustment is achieved to improve the measurement accuracy of the grazing incidence interferometer device; by determining the mapping relationship between the incident sample angle and the phase, and then determining multiple incident sample angles corresponding to the preset constant phase difference, the phase difference of all adjacent first interference patterns can be close to or reach the preset constant phase difference, thereby enhancing the accuracy of the air gap thickness calculation, and further, it can also help optimize the quality of the interference fringes, improve the overall performance of the interference measurement, and achieve the effect of improving the measurement accuracy of the grazing incidence interferometer device; by calculating the optical path angle information based on the incident sample angle once, the incident and exit characteristics of the light on the sample surface can be accurately determined, thereby improving the accuracy of the air gap thickness measurement. Accuracy is improved to achieve the effect of improving the measurement accuracy of the grazing incidence interferometer device; by combining in steps and then analyzing, the measurement accuracy can be improved, and the reliability and consistency of the results can be enhanced, which is conducive to more accurate calculation of the air gap thickness, thereby achieving the effect of improving the measurement accuracy of the grazing incidence interferometer device; by calculating the air gap thickness of each first sub-interference pattern group based on the incident sample angle of the first interference pattern in each first sub-interference pattern group, the phase difference between the first interference pattern and the first first interference pattern, and the laser wavelength of the grazing incidence interferometer device, the measurement accuracy can be improved, and the robustness and consistency of the measurement results can be enhanced, thereby achieving the effect of improving the measurement accuracy of the grazing incidence interferometer device;By calculating the phase difference of each first sub-interference pattern group according to the optical path angle information, the incident sample angle derivative and the laser wavelength of the grazing incidence interference device, and then calculating the air gap thickness of each first sub-interference pattern group according to the optical path angle information of each first sub-interference pattern group, the laser wavelength of the grazing incidence interference device and the phase difference of the first sub-interference pattern group, the partial derivative calculation of the air gap thickness can be achieved, the accuracy of the measurement can be improved, and the robustness and consistency of the measurement results can be enhanced, so as to achieve the effect of improving the measurement accuracy of the grazing incidence interference device. At the same time, the air gap measurement method of this embodiment does not need to modify the structure of the existing grazing incidence interferometer or introduce additional hardware, which can avoid the increase of cost. Without introducing other hardware, the non-contact measurement of the sample to be measured can be achieved, which can further achieve the effect of improving the measurement accuracy of the non-contact grazing incidence interference device. ;

[0104] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0105] Based on the same inventive concept, the embodiment of the present application also provides an air gap measuring device for implementing the air gap measuring method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more air gap measuring device embodiments provided below can refer to the limitations of the air gap measuring method above, and will not be repeated here.

[0106] In one embodiment, Fig. 9 As shown, an air gap measurement device is provided, which is applied to a grazing incidence interferometer. The air gap measurement device comprises: The pattern group acquisition module 100 is used to acquire a first interference pattern group of the sample to be tested. The first interference pattern group includes at least two first interference patterns obtained based on different incident sample angles.

[0107] The thickness calculation module 200 is used to calculate the air gap thickness of the sample to be measured based on the optical path angle information of the multiple first interference patterns and the phase difference between adjacent first interference patterns.

[0108] In some embodiments, the image group acquisition module 100 is further used for: Obtaining an initial interference pattern group of the sample to be tested; the initial interference pattern group includes at least two initial interference patterns obtained based on different incident sample angles; Based on the initial interference pattern group of the sample to be tested, determining the light beam phase difference data of the initial interference pattern group; Determine a plurality of incident sample angles corresponding to the preset constant phase difference based on the preset constant phase difference, the beam phase difference data of the initial interference pattern group and the incident sample angle corresponding to each of the initial interference patterns; A first set of interference patterns is obtained based on a plurality of incident sample angles corresponding to the preset constant phase difference.

[0109] In some embodiments, the image group acquisition module 100 is further used for: Calculating the phase difference between each of the initial interference patterns and the first initial interference pattern in sequence to obtain an initial phase difference of each of the initial interference patterns; Based on the initial phase differences of the multiple initial interference patterns, the beam phase difference data of the initial interference pattern group is obtained.

[0110] In some embodiments, the image group acquisition module 100 is further used for: Determining the mapping relationship between the incident sample angle and the phase difference based on the beam phase difference data of the initial interference pattern group; Based on the preset constant phase difference and the mapping relationship, a plurality of incident sample angles corresponding to the preset constant phase difference are determined.

[0111] In some embodiments, the thickness calculation module 200 is further used to: Based on the prism incident angle corresponding to each of the first interference patterns, respectively determine the optical path angle information of each of the first interference patterns; the optical path angle information includes the prism incident angle, the first refraction angle, the first incident angle and the incident sample angle; the prism includes a right-angle surface and an inclined surface; The air gap thickness of the sample to be measured is calculated based on the optical path angle information corresponding to each of the first interference patterns and the phase difference between the first interference patterns.

[0112] In some embodiments, the thickness calculation module 200 is further used to: Determining a first refraction angle based on the prism incident angle, the air refractive index, and the prism refractive index; Determining a first incident angle based on a geometric relationship between the first refraction angle and the first incident angle; Based on the first incident angle, the air refractive index and the prism refractive index, an incident sample angle is determined.

[0113] In some embodiments, the thickness calculation module 200 is further used to: Combining any first interference pattern with the remaining first interference patterns in pairs in sequence to obtain a plurality of first sub-interference pattern groups; Calculating the incident sample angle derivative of each of the first sub-interference pattern groups in turn; Calculating the phase difference of each of the first sub-interference pattern groups based on the optical path angle information, the incident sample angle deflection and the laser wavelength of the grazing incidence interferometer; Calculating the air gap thickness of each of the first sub-interference pattern groups based on the optical path angle information of each of the first sub-interference pattern groups, the laser wavelength of the grazing incidence interferometer device, and the phase difference of the first sub-interference pattern group; The air gap thickness of the sample to be tested is determined based on the air gap thicknesses of the plurality of first sub-interference pattern groups.

[0114] In some embodiments, the thickness calculation module 200 is further used to: Combining any first interference pattern with the remaining first interference patterns in pairs in sequence to obtain a plurality of first sub-interference pattern groups; Calculating the air gap thickness of each first sub-interference pattern group based on the incident sample angle of the first interference pattern in each first sub-interference pattern group, the phase difference of the first interference pattern group, and the laser wavelength of the grazing incidence interferometer device; The air gap thickness of the sample to be tested is determined based on the air gap thicknesses of the plurality of first sub-interference pattern groups.

[0115] In some embodiments, the thickness calculation module 200 is further used to: The air gap thickness of the sample to be tested is obtained by calculating an average value based on the air gap thicknesses of the plurality of first sub-interference pattern groups.

[0116] Each module in the above-mentioned air gap measurement device can be implemented in whole or in part by software, hardware or a combination thereof. Each of the above-mentioned modules can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to each of the above modules.

[0117] In one embodiment, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as follows: Fig.10As shown. The computer device includes a processor, a memory, a communication interface, a display screen and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, an air gap measurement method is implemented. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covered on the display screen, or a key, trackball or touchpad set on the computer device shell, or an external keyboard, touchpad or mouse, etc.

[0118] Those skilled in the art will understand that Fig.10 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0119] In one embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the air gap measurement method of any of the above embodiments is implemented: Acquire a first interference pattern group of the sample to be tested; the first interference pattern group includes at least two first interference patterns obtained based on different incident sample angles; Calculating the optical path angle information of each of the first interference patterns in the first interference pattern group respectively; the optical path angle information includes the angle of the light relative to the prism medium surface during the process from incident to emitted; the prism medium surface includes a right-angle surface and an inclined surface; The air gap thickness of the sample to be measured is calculated based on the optical path angle information of the plurality of first interference patterns and the phase difference between adjacent first interference patterns.

[0120] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the air gap measurement method of any of the above embodiments is implemented: Acquire a first interference pattern group of the sample to be tested; the first interference pattern group includes at least two first interference patterns obtained based on different incident sample angles; Calculating the optical path angle information of each of the first interference patterns in the first interference pattern group respectively; the optical path angle information includes the angle of the light relative to the prism medium surface during the process from incident to emitted; the prism medium surface includes a right-angle surface and an inclined surface; The air gap thickness of the sample to be measured is calculated based on the optical path angle information of the plurality of first interference patterns and the phase difference between adjacent first interference patterns.

[0121] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0122] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0123] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0124] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. An air gap measurement method, characterized in that: Applied to a grazing incidence interferometer, the air gap measurement method comprises: Acquire a first interference pattern group of the sample to be tested; the first interference pattern group includes at least two first interference patterns obtained based on different incident sample angles; The air gap thickness of the sample to be measured is calculated based on the incident sample angle corresponding to each of the first interference patterns and the phase difference between the first interference patterns.

2. The air gap measurement method according to claim 1, characterized in that: The step of obtaining a first interference pattern group of the sample to be tested comprises: Obtaining an initial interference pattern group of the sample to be tested; the initial interference pattern group includes at least two initial interference patterns obtained based on different incident sample angles; Based on the initial interference pattern group of the sample to be tested, determining the light beam phase difference data of the initial interference pattern group; Determine a plurality of incident sample angles corresponding to the preset constant phase difference based on the preset constant phase difference, the beam phase difference data of the initial interference pattern group and the incident sample angle corresponding to each of the initial interference patterns; A first set of interference patterns is obtained based on a plurality of incident sample angles corresponding to the preset constant phase difference.

3. The air gap measurement method according to claim 2, characterized in that: The step of determining the beam phase difference data of the initial interference pattern group based on the sample to be tested includes: Calculating the phase difference between each of the initial interference patterns and the first initial interference pattern in sequence to obtain an initial phase difference of each of the initial interference patterns; Based on the initial phase differences of the multiple initial interference patterns, the beam phase difference data of the initial interference pattern group is obtained.

4. The air gap measurement method according to claim 3, characterized in that: The step of determining a plurality of incident sample angles corresponding to the preset constant phase difference based on the preset constant phase difference and the beam phase difference data of the initial interference pattern group comprises: Determining the mapping relationship between the incident sample angle and the phase difference based on the beam phase difference data of the initial interference pattern group; Based on the preset constant phase difference and the mapping relationship, a plurality of incident sample angles corresponding to the preset constant phase difference are determined.

5. The air gap measurement method according to claim 1, characterized in that: The air gap measurement method further comprises: Based on the prism incident angle corresponding to each of the first interference patterns, respectively determine the optical path angle information of each of the first interference patterns; the optical path angle information includes the prism incident angle, the first refraction angle, the first incident angle and the incident sample angle; the prism includes a right-angle surface and an inclined surface; The air gap thickness of the sample to be measured is calculated based on the optical path angle information corresponding to each of the first interference patterns and the phase difference between the first interference patterns.

6. The air gap measurement method according to claim 5, characterized in that: The determining of the optical path angle information of each of the first interference patterns based on the prism incident angle corresponding to each of the first interference patterns comprises: Determining a first refraction angle based on the prism incident angle, the air refractive index, and the prism refractive index; Determining a first incident angle based on a geometric relationship between the first refraction angle and the first incident angle; Based on the first incident angle, the air refractive index and the prism refractive index, an incident sample angle is determined.

7. The air gap measurement method according to claim 5, characterized in that: The step of calculating the air gap thickness of the sample to be measured based on the optical path angle information corresponding to each of the first interference patterns and the phase difference between the first interference patterns further includes: Combining any first interference pattern with the remaining first interference patterns in pairs in sequence to obtain a plurality of first sub-interference pattern groups; Calculating the incident sample angle derivative of each of the first sub-interference pattern groups in turn; Calculating the phase difference of each of the first sub-interference pattern groups based on the optical path angle information, the incident sample angle deflection and the laser wavelength of the grazing incidence interferometer; Calculating the air gap thickness of each of the first sub-interference pattern groups based on the optical path angle information of each of the first sub-interference pattern groups, the laser wavelength of the grazing incidence interferometer device, and the phase difference of the first sub-interference pattern group; The air gap thickness of the sample to be tested is determined based on the air gap thicknesses of the plurality of first sub-interference pattern groups.

8. The air gap measurement method according to claim 1, characterized in that: The phase difference between the incident sample angle corresponding to each of the first interference patterns and the first interference pattern comprises: Combining any first interference pattern with the remaining first interference patterns in pairs in sequence to obtain a plurality of first sub-interference pattern groups; Calculating the air gap thickness of each first sub-interference pattern group based on the incident sample angle of the first interference pattern in each first sub-interference pattern group, the phase difference of the first interference pattern group, and the laser wavelength of the grazing incidence interferometer device; The air gap thickness of the sample to be tested is determined based on the air gap thicknesses of the plurality of first sub-interference pattern groups.

9. The air gap measurement method according to claim 7 or claim 8, characterized in that: The determining the air gap thickness of the sample to be tested based on the air gap thicknesses of the plurality of first sub-interference pattern groups comprises: The air gap thickness of the sample to be tested is obtained by calculating an average value based on the air gap thicknesses of the plurality of first sub-interference pattern groups.

10. An air gap measuring device, characterized in that: Applied to a grazing incidence interferometer, the air gap measurement device comprises: A pattern group acquisition module, used to acquire a first interference pattern group of the sample to be tested; the first interference pattern group includes at least two first interference patterns obtained based on different incident sample angles; The thickness calculation module is used to calculate the air gap thickness of the sample to be measured based on the incident sample angle corresponding to each of the first interference patterns and the phase difference between the first interference patterns.

11. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the method according to any one of claims 1 to 9 is implemented.

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