A film thickness measurement method, system, device, and storage medium
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- WUHAN YISIPU TECH CO LTD
- Filing Date
- 2026-05-07
- Publication Date
- 2026-08-07
AI Technical Summary
导致现有方法计算得到等效折射率是有一定偏差的，而薄膜系统厚度分析方法中基于快速傅里叶变换分析方法得到的薄膜厚度，其实与样品的真实薄膜厚度也是有一定的偏差
[0023]本发明首先构建基于标定的等效折射率算法和基于色散模型系数修正的等效折射率算法，并将基于标定的等效折射率算法和基于色散模型系数修正的等效折射率算法存储至预设等效折射率计算库内，然后获取待测样品，并确定待测样品对应的入射光波段范围，根据待测样品从预设等效折射率计算库中选取对应的等效折射率算法，之后基于入射光波段范围通过选取的等效折射率算法计算待测样品的等效折射率，最后根据等效折射率对待测样品进行膜厚测定。本发明通过基于标定的等效折射率算法或基于色散模型系数修正的等效折射率算法解决了等效折射率的偏差，从而实现精准的膜厚测定。
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Abstract
Description
Technical Field
[0001] This invention relates to the field of film thickness measurement technology, and in particular to a film thickness measurement method, system, device and storage medium. Background Technology
[0002] In the fields of optics and materials science, thin-film systems are widely used in optical coatings, semiconductor manufacturing, biosensors, and other high-tech applications. Thin-film systems achieve specific optical functions by controlling the reflection, transmission, and absorption properties of light. Optical reflectance measurement is an analytical technique that utilizes the reflection phenomenon that occurs when light interacts with matter to obtain information about the physical properties and structure of an object. By measuring and calculating the reflectance of the spectrum of a thin-film system, important information about the surface properties and internal structure of the material can be obtained.
[0003] With the development of semiconductor technology, the accurate measurement and simulation of the optical properties of thin-film systems has become an increasingly important research focus. Currently, there are two main methods for measuring the thickness of thin-film systems: nonlinear regression analysis and fast Fourier transform analysis. Nonlinear regression analysis involves pre-constructing a theoretical spectral library within a certain thickness range and then searching the library for the measured spectral reflectance. Fast Fourier transform analysis, on the other hand, first performs a Fourier transform on the measured spectral reflectance, then identifies the peak position in the spectrum, and finally divides by the equivalent refractive index to obtain the film thickness. Fast Fourier transform is suitable for thin-film systems of 1µm and above. In industrial applications, combining these two methods enables the measurement of the thickness of various thin-film systems.
[0004] However, existing fast Fourier transform (FFT) analysis methods calculate the equivalent refractive index based on the assumption that the refractive index and wavelength of a material have a linear relationship. In reality, the refractive index and wavelength of most materials satisfy a second-order dispersion model. This leads to a certain deviation in the equivalent refractive index calculated by existing methods. Similarly, the film thickness obtained from FFT analysis in thin film system thickness analysis also deviates from the actual film thickness of the sample.
[0005] Therefore, how to avoid deviations in the equivalent refractive index and achieve accurate film thickness measurement has become an urgent problem to be solved.
[0006] The above content is only used to help understand the technical solution of the present invention and does not represent an admission that the above content is prior art. Summary of the Invention
[0007] The main objective of this invention is to provide a film thickness measurement method, system, device, and storage medium, aiming to solve the technical problem of how to avoid deviations in equivalent refractive index and achieve accurate film thickness measurement.
[0008] To achieve the above objectives, the present invention provides a film thickness measurement method, the film thickness measurement method comprising: Construct an equivalent refractive index algorithm based on calibration and an equivalent refractive index algorithm based on dispersion model coefficient correction, and store the equivalent refractive index algorithm based on calibration and the equivalent refractive index algorithm based on dispersion model coefficient correction in a preset equivalent refractive index calculation library; Acquire the sample to be tested and determine the incident light wavelength range corresponding to the sample to be tested; The corresponding equivalent refractive index algorithm is selected from the preset equivalent refractive index calculation library based on the sample to be tested; The equivalent refractive index of the sample under test is calculated based on the incident light wavelength range using a selected equivalent refractive index algorithm. The film thickness of the sample under test is determined based on the equivalent refractive index.
[0009] Optionally, the step of selecting the corresponding equivalent refractive index algorithm from the preset equivalent refractive index calculation library based on the sample to be tested includes: The presence of a calibrated thin film thickness in the sample under test is detected. If it exists, the calibration-based equivalent refractive index algorithm is selected from the preset equivalent refractive index calculation library; If it does not exist, the equivalent refractive index algorithm based on dispersion model coefficient correction is selected from the preset equivalent refractive index calculation library.
[0010] Optionally, the step of calculating the equivalent refractive index of the sample under test based on the incident light wavelength range using a selected equivalent refractive index algorithm includes: When the selected equivalent refractive index algorithm is the calibration-based equivalent refractive index algorithm, the measured light intensity of the sample to be tested is determined based on the incident light band range, and the measured light intensity reflectance is calculated based on the measured light intensity. The measured light intensity reflectance is transformed using the Fourier transform formula to obtain the spectrum value; The frequency domain position corresponding to the film thickness is determined based on the spectral value; The equivalent refractive index of the sample under test is calculated using the calibration-based equivalent refractive index algorithm based on the frequency domain position and the film thickness.
[0011] Optionally, the Fourier transform formula is:
[0012] In the formula, The starting point of the wavelength of the incident light. The wavelength of the incident light ends. wavelength Corresponding light intensity reflectivity, For spectral values, The frequency variable is the result of the Fourier transform. It is the imaginary unit.
[0013] Optionally, determining the frequency domain position corresponding to the film thickness based on the spectral value includes: The position of the highest peak is determined based on the spectral value, and the position of the highest peak is used as the frequency domain position corresponding to the film thickness.
[0014] Optionally, the calibration-based equivalent refractive index algorithm is as follows:
[0015] In the formula, For equivalent refractive index, , and These represent different film thicknesses corresponding to test samples made of the same material. , and These represent the frequency domain positions corresponding to different film thicknesses.
[0016] Optionally, the step of calculating the equivalent refractive index of the sample under test based on the incident light wavelength range using a selected equivalent refractive index algorithm further includes: When the selected equivalent refractive index algorithm is the equivalent refractive index algorithm based on the dispersion model coefficient correction, the maximum and minimum incident wavelengths of the sample under test are determined according to the incident light band range. The equivalent refractive index of the sample under test is calculated using an equivalent refractive index algorithm based on the maximum and minimum incident wavelengths. The equivalent refractive index algorithm based on dispersion model coefficient correction is as follows:
[0017]
[0018]
[0019] In the formula, The maximum value of the incident wavelength. This is the minimum incident wavelength. For the sample to be tested at a wavelength of The corresponding light intensity refractive index, For the sample to be tested at a wavelength of The corresponding light intensity refractive index, It is the equivalent refractive index.
[0020] Furthermore, to achieve the above objectives, the present invention also proposes a film thickness measurement system, the film thickness measurement system comprising: A construction module is used to construct an equivalent refractive index algorithm based on calibration and an equivalent refractive index algorithm based on dispersion model coefficient correction, and to store the equivalent refractive index algorithm based on calibration and the equivalent refractive index algorithm based on dispersion model coefficient correction into a preset equivalent refractive index calculation library; The acquisition module is used to acquire the sample to be tested and determine the incident light wavelength range corresponding to the sample to be tested. The selection module is used to select the corresponding equivalent refractive index algorithm from the preset equivalent refractive index calculation library according to the sample to be tested; The calculation module is used to calculate the equivalent refractive index of the sample under test based on the incident light wavelength range using a selected equivalent refractive index algorithm. The measurement module is used to measure the film thickness of the sample under test based on the equivalent refractive index.
[0021] Furthermore, to achieve the above objectives, the present invention also proposes a film thickness measuring device, the device comprising: a memory, a processor, and a film thickness measuring program stored in the memory and executable on the processor, the film thickness measuring program being configured to implement the steps of the film thickness measuring method as described above.
[0022] In addition, to achieve the above objectives, the present invention also proposes a storage medium storing a film thickness measurement program, which, when executed by a processor, implements the steps of the film thickness measurement method as described above.
[0023] This invention first constructs an equivalent refractive index algorithm based on calibration and an equivalent refractive index algorithm based on dispersion model coefficient correction, and stores these algorithms in a preset equivalent refractive index calculation library. Then, it acquires the sample to be tested and determines the incident light wavelength range corresponding to the sample. Based on the sample, it selects the corresponding equivalent refractive index algorithm from the preset equivalent refractive index calculation library. Next, it calculates the equivalent refractive index of the sample based on the selected algorithm within the incident light wavelength range. Finally, it measures the film thickness of the sample based on the equivalent refractive index. This invention solves the problem of equivalent refractive index deviation by using either a calibration-based or dispersion model coefficient-corrected equivalent refractive index algorithm, thereby achieving accurate film thickness measurement. Attached Figure Description
[0024] Figure 1 This is a schematic diagram of the film thickness measuring device in the hardware operating environment involved in the embodiments of the present invention; Figure 2 This is a schematic flowchart of the first embodiment of the film thickness measurement method of the present invention; Figure 3 This is a structured light intensity reflectance diagram of the first embodiment of the film thickness measurement method of the present invention; Figure 4 This is a Fourier transform result diagram of the first embodiment of the film thickness measurement method of the present invention; Figure 5 This is a structural block diagram of the first embodiment of the film thickness measurement system of the present invention.
[0025] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation
[0026] It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.
[0027] Reference Figure 1 , Figure 1 This is a schematic diagram of the end-to-end robust time synchronization device structure of the Advanced Driver Assistance Systems (ADAS) hardware operating environment involved in the embodiments of the present invention.
[0028] like Figure 1 As shown, the film thickness measuring device may include: a processor 1001, such as a central processing unit (CPU), a communication bus 1002, a user interface 1003, a network interface 1004, and a memory 1005. The communication bus 1002 is used to enable communication between these components. The user interface 1003 may include a display screen or an input unit such as a keyboard; optionally, the user interface 1003 may also include a standard wired interface or a wireless interface. The network interface 1004 may optionally include a standard wired interface or a wireless interface (such as a Wireless-Fidelity (Wi-Fi) interface). The memory 1005 may be high-speed random access memory (RAM) or stable non-volatile memory (NVM), such as a disk storage device. Optionally, the memory 1005 may also be a storage system independent of the aforementioned processor 1001.
[0029] Those skilled in the art will understand that Figure 1 The structure shown does not constitute a limitation on the film thickness measuring device and may include more or fewer components than shown, or combine certain components, or have different component arrangements.
[0030] like Figure 1As shown, the memory 1005, which serves as a storage medium, may include an operating system, a network access module, a user interface module, and a film thickness measurement program.
[0031] exist Figure 1 In the film thickness measuring device shown, the network interface 1004 is mainly used for data communication with the network server; the user interface 1003 is mainly used for data interaction with the user; the processor 1001 and the memory 1005 in the film thickness measuring device of the present invention can be set in the film thickness measuring device. The film thickness measuring device calls the film thickness measuring program stored in the memory 1005 through the processor 1001 and executes the film thickness measuring method provided in the embodiment of the present invention.
[0032] This invention provides a method for measuring film thickness, referring to... Figure 2 , Figure 2 This is a schematic flowchart of the first embodiment of the film thickness measurement method of the present invention.
[0033] In this embodiment, the film thickness measurement method includes the following steps: S1. Construct an equivalent refractive index algorithm based on calibration and an equivalent refractive index algorithm based on dispersion model coefficient correction, and store the equivalent refractive index algorithm based on calibration and the equivalent refractive index algorithm based on dispersion model coefficient correction in a preset equivalent refractive index calculation library.
[0034] It is easy to understand that the execution subject of this embodiment can be a film thickness measurement system with functions such as data processing, network communication and program operation, or other computer equipment with similar functions. This embodiment does not limit it.
[0035] It should be noted that since the refractive index of a material is only related to the wavelength of the incident light and the material itself, and not to the thickness of the material, the equivalent refractive index is also only related to the wavelength of the incident light and the material itself, and not to the thickness. Therefore, we construct an equivalent refractive index algorithm based on calibration and an equivalent refractive index algorithm based on dispersion model coefficient correction to calculate the equivalent refractive index.
[0036] S2, acquire the sample to be tested, and determine the incident light wavelength range corresponding to the sample to be tested.
[0037] It should be understood that the incident light wavelength range can be customized by the user.
[0038] S3, select the corresponding equivalent refractive index algorithm from the preset equivalent refractive index calculation library according to the sample to be tested.
[0039] Furthermore, the presence of a calibrated thin film thickness in the sample to be tested is detected; if it exists, an equivalent refractive index algorithm based on the calibration is selected from the preset equivalent refractive index calculation library; if it does not exist, an equivalent refractive index algorithm based on dispersion model coefficient correction is selected from the preset equivalent refractive index calculation library.
[0040] In practice, users can also actively select the equivalent refractive index algorithm according to their own needs.
[0041] S4, calculate the equivalent refractive index of the sample under test based on the incident light wavelength range using the selected equivalent refractive index algorithm.
[0042] Furthermore, the processing method for calculating the equivalent refractive index of the sample under test based on the incident light wavelength range using the selected equivalent refractive index algorithm is as follows: When the selected equivalent refractive index algorithm is a calibrated equivalent refractive index algorithm, the measured light intensity of the sample under test is determined based on the incident light wavelength range, and the measured light intensity reflectance is calculated based on the measured light intensity; the measured light intensity reflectance is transformed using the Fourier transform formula to obtain the spectrum value; the position of the highest peak is determined based on the spectrum value, and the position of the highest peak is used as the frequency domain position corresponding to the film thickness; the equivalent refractive index of the sample under test is calculated based on the frequency domain position and the film thickness using the calibrated equivalent refractive index algorithm.
[0043] In practice, the process of calculating the equivalent refractive index of the sample under test using a calibration-based equivalent refractive index algorithm is as follows: Step 1: For the given sample A1 to be tested, obtain its film thickness d1 by measurement and calibration; Step 2: Given the wavelength range of the incident light, obtain the measured light intensity E1 of the sample A1 to be tested, and then calculate the measured light intensity reflectance R1 of the sample based on the measured light intensity of A1.
[0044] The method for calculating light intensity reflectance is generally to divide the measured light intensity by the intensity of the incident light. For example, if the incident light wavelength is 400nm-700nm, and at a certain wavelength (such as 550nm), the incident light intensity is E0=100, and the measured reflected light intensity of the sample is E1=35, then the reflectance at that wavelength is 35 / 100 = 0.35. The light intensity reflectance R1 of the sample under test can be calculated for each wavelength.
[0045] Step 3: Perform a fast Fourier transform on the obtained light intensity reflectivity R1 to obtain its spectral value F1.
[0046] The Fourier transform formula is:
[0047] In the formula, The starting point of the wavelength of the incident light. The wavelength of the incident light ends. wavelength Corresponding light intensity reflectivity, For spectral values, The frequency variable after Fourier transform (used to represent the wave components at different speeds in the reflectivity curve). It is the imaginary unit.
[0048] Step 4: Find the position corresponding to the highest peak of spectrum F1, and then obtain the frequency domain position corresponding to the film thickness as nd1.
[0049] Given test samples of the same material but different thicknesses, repeat steps 1 to 4 to obtain test samples A2 and A3 with different thicknesses, whose corresponding film thicknesses are d2 and d3. Calculate the light intensity reflectances R2 and R3, and the film thickness positions corresponding to the spectral peaks after Fourier transform are nd2 and nd3, respectively.
[0050] The algorithm based on the calibrated equivalent refractive index is as follows:
[0051] In the formula, Let A1 be the equivalent refractive index of the sample to be tested. , and These represent different film thicknesses corresponding to test samples made of the same material. , and These represent the frequency domain positions corresponding to different film thicknesses.
[0052] Furthermore, the processing method for calculating the equivalent refractive index of the sample under test based on the incident light wavelength range using the selected equivalent refractive index algorithm is as follows: when the selected equivalent refractive index algorithm is the equivalent refractive index algorithm based on dispersion model coefficient correction, the maximum and minimum incident wavelengths of the sample under test are determined according to the incident light wavelength range; the equivalent refractive index of the sample under test is calculated based on the maximum and minimum incident wavelengths using the equivalent refractive index algorithm based on dispersion model coefficient correction.
[0053] In practical implementation, the process of constructing a calibration-based equivalent refractive index algorithm is as follows: The existing method for calculating equivalent refractive index, which is based on the linear relationship between material refractive index and wavelength, is modified using the formula for calculating equivalent refractive index. Specifically: Step 1: The refractive index of the given thin film sample is expressed using a second-order dispersion model as follows:
[0054] in Let a be the incident wavelength, and a, b, and c be the dispersion model coefficients. That is, the sample to be tested at a wavelength of The refractive index of light intensity at a given time can be obtained by measurement, and then the model coefficients a, b, and c can be calculated.
[0055] The model coefficients a, b, and c can be calculated by measuring three sets of data using specialized equipment, such as wavelength. 1. Obtain the corresponding refractive index n1; wavelength 2. Obtain the corresponding refractive index n2; wavelength 3. Obtain the corresponding refractive index n3; substitute these three sets of data into the above second-order dispersion model equation, and by solving this system of three linear equations, we can obtain the corresponding a, b, and c.
[0056] Step 2: The formula for calculating the equivalent refractive index of the thin film to be tested is:
[0057] in, and These are the maximum and minimum values of the incident wavelength, respectively. For the incident wavelength variable, For the sample to be tested at a wavelength of The corresponding light intensity refractive index, This is the equivalent refractive index.
[0058] The formula for calculating the equivalent refractive index based on the dispersion model in step 1 is:
[0059] Step 3: The formula for calculating the equivalent refractive index in the fast Fourier transform analysis of the thin film system is as follows:
[0060] in, and These are the maximum and minimum values of the incident wavelength, respectively. and The corresponding refractive index of light intensity. This is the equivalent refractive index. It also incorporates the linear relationship between refractive index and wavelength as follows:
[0061] And the first-order approximate derivation in the process of calculating the equivalent refractive index.
[0062] Step 4: Add the missing second-order terms:
[0063] pass The second-order dispersion model equation yields the formula for calculating the coefficient c:
[0064] in: It is derived through the first derivative.
[0065] Therefore, the equivalent refractive index algorithm based on the dispersion model coefficient correction is obtained as follows:
[0066] Once the maximum and minimum incident wavelengths of the sample to be tested and the corresponding material refractive index are determined, the equivalent refractive index of the sample to be tested can be calculated using the above formula for calculating the equivalent refractive index.
[0067] S5, the film thickness of the sample to be tested is measured according to the equivalent refractive index.
[0068] After obtaining the equivalent refractive index of the thin film of the sample under test through the above two methods, it can be directly used in the subsequent fast Fourier transform analysis of the film thickness calculation system to obtain a more accurate film thickness of the sample under test.
[0069] It should also be noted that the equivalent refractive index algorithm based on dispersion model coefficient correction proposed in this invention was practically verified using structures with a Si layer as the substrate, a SiO2 layer on top of the Si layer, and a Si layer on top of the SiO2 layer. (Refer to...) Figure 3 , Figure 3 This is a structured light intensity reflectance diagram of the first embodiment of the film thickness measurement method of the present invention.
[0070] The film thickness calculated using the Fast Fourier Transform (FFT) analysis method in the previous film thickness calculation method was 96375.2532 Å. However, after correcting the equivalent refractive index using the method proposed in Scheme 2, the film thickness calculated using the FFT analysis method was 96055.1311 Å, which is closer to the actual film thickness of 96000 Å, achieving the desired correction effect. (FFT results reference) Figure 4 , Figure 4 This is a Fourier transform result diagram of the first embodiment of the film thickness measurement method of the present invention.
[0071] Reference Figure 5 , Figure 5 This is a structural block diagram of the first embodiment of the film thickness measurement system of the present invention.
[0072] like Figure 5 As shown, the film thickness measurement system proposed in this embodiment of the invention includes: The construction module 5001 is used to construct an equivalent refractive index algorithm based on calibration and an equivalent refractive index algorithm based on dispersion model coefficient correction, and to store the equivalent refractive index algorithm based on calibration and the equivalent refractive index algorithm based on dispersion model coefficient correction into a preset equivalent refractive index calculation library. The acquisition module 5002 is used to acquire the sample to be tested and determine the incident light wavelength range corresponding to the sample to be tested. The selection module 5003 is used to select the corresponding equivalent refractive index algorithm from the equivalent refractive index calculation library according to the sample to be tested; The calculation module 5004 is used to calculate the equivalent refractive index of the sample under test based on the incident light wavelength range using a selected equivalent refractive index algorithm. Measurement module 5005 is used to measure the film thickness of the sample to be tested based on the equivalent refractive index.
[0073] Other embodiments or specific implementations of the film thickness measurement system of the present invention can be referred to the above-described method embodiments, and will not be repeated here.
[0074] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.
[0075] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.
[0076] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as read-only memory / random access memory, magnetic disk, optical disk) and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of the present invention.
[0077] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.
Claims
1. A method for measuring film thickness, characterized in that, The method includes the following steps: Construct an equivalent refractive index algorithm based on calibration and an equivalent refractive index algorithm based on dispersion model coefficient correction, and store the equivalent refractive index algorithm based on calibration and the equivalent refractive index algorithm based on dispersion model coefficient correction in a preset equivalent refractive index calculation library; Acquire the sample to be tested and determine the incident light wavelength range corresponding to the sample to be tested; The corresponding equivalent refractive index algorithm is selected from the preset equivalent refractive index calculation library based on the sample to be tested; The equivalent refractive index of the sample under test is calculated based on the incident light wavelength range using a selected equivalent refractive index algorithm. The film thickness of the sample under test is determined based on the equivalent refractive index.
2. The method as described in claim 1, characterized in that, The step of selecting the corresponding equivalent refractive index algorithm from the preset equivalent refractive index calculation library based on the sample to be tested includes: The presence of a calibrated thin film thickness in the sample under test is detected. If it exists, the calibration-based equivalent refractive index algorithm is selected from the preset equivalent refractive index calculation library; If it does not exist, the equivalent refractive index algorithm based on dispersion model coefficient correction is selected from the preset equivalent refractive index calculation library.
3. The method as described in claim 2, characterized in that, The calculation of the equivalent refractive index of the sample under test based on the incident light wavelength range using a selected equivalent refractive index algorithm includes: When the selected equivalent refractive index algorithm is the calibration-based equivalent refractive index algorithm, the measured light intensity of the sample to be tested is determined based on the incident light band range, and the measured light intensity reflectance is calculated based on the measured light intensity. The measured light intensity reflectance is transformed using the Fourier transform formula to obtain the spectrum value; The frequency domain position corresponding to the film thickness is determined based on the spectral value; The equivalent refractive index of the sample under test is calculated using the calibration-based equivalent refractive index algorithm based on the frequency domain position and the film thickness.
4. The method as described in claim 3, characterized in that, The Fourier transform formula is as follows: In the formula, The starting point of the wavelength of the incident light. The wavelength of the incident light ends. wavelength Corresponding light intensity reflectivity, For spectral values, The frequency variable is the result of the Fourier transform. It is the imaginary unit.
5. The method as described in claim 3, characterized in that, Determining the frequency domain position corresponding to the film thickness based on the spectral value includes: The position of the highest peak is determined based on the spectral value, and the position of the highest peak is used as the frequency domain position corresponding to the film thickness.
6. The method as described in claim 3, characterized in that, The calibrated equivalent refractive index algorithm is as follows: In the formula, For equivalent refractive index, , and These represent different film thicknesses corresponding to test samples made of the same material. , and These represent the frequency domain positions corresponding to different film thicknesses.
7. The method as described in claim 2, characterized in that, The step of calculating the equivalent refractive index of the sample under test based on the incident light wavelength range using a selected equivalent refractive index algorithm further includes: When the selected equivalent refractive index algorithm is the equivalent refractive index algorithm based on the dispersion model coefficient correction, the maximum and minimum incident wavelengths of the sample under test are determined according to the incident light band range. The equivalent refractive index of the sample under test is calculated using an equivalent refractive index algorithm based on the maximum and minimum incident wavelengths. The equivalent refractive index algorithm based on dispersion model coefficient correction is as follows: In the formula, The maximum value of the incident wavelength. This is the minimum incident wavelength. For the sample to be tested at a wavelength of The corresponding light intensity refractive index, For the sample to be tested at a wavelength of The corresponding light intensity refractive index, It is the equivalent refractive index.
8. A film thickness measurement system, characterized in that, The system includes: A construction module is used to construct an equivalent refractive index algorithm based on calibration and an equivalent refractive index algorithm based on dispersion model coefficient correction, and to store the equivalent refractive index algorithm based on calibration and the equivalent refractive index algorithm based on dispersion model coefficient correction into a preset equivalent refractive index calculation library; The acquisition module is used to acquire the sample to be tested and determine the incident light wavelength range corresponding to the sample to be tested. The selection module is used to select the corresponding equivalent refractive index algorithm from the preset equivalent refractive index calculation library according to the sample to be tested; The calculation module is used to calculate the equivalent refractive index of the sample under test based on the incident light wavelength range using a selected equivalent refractive index algorithm. The measurement module is used to measure the film thickness of the sample under test based on the equivalent refractive index.
9. A film thickness measuring device, characterized in that, The device includes: a memory, a processor, and a film thickness measurement program stored in the memory and executable on the processor, the film thickness measurement program being configured to implement the steps of the film thickness measurement method as described in any one of claims 1 to 7.
10. A storage medium, characterized in that, The storage medium stores a film thickness measurement program, which, when executed by a processor, implements the steps of the film thickness measurement method as described in any one of claims 1 to 7.