A method and device for acquiring film parameters and a terminal device

Abstract

The application discloses a film parameter acquisition method and device and a terminal device. The method comprises the following steps: obtaining a function relationship of a film, wherein the independent variable of the function relationship comprises the thickness and optical constant of each layer of the film, and the dependent variable comprises the reflection light polarization information of the film; substituting the product of the thickness estimation value of each layer of the film and the corresponding coefficient of each layer and the estimation value of the optical constant of each layer into the function relationship to obtain a reflection light polarization information simulation value, the coefficients corresponding to the same material layer in the film being the same; when the difference between the simulation value and the experimental value of the reflection light polarization information of the film satisfies a preset condition, taking the product of the thickness estimation value of each layer of the film and the corresponding coefficient of each layer as the actual value of the thickness, and taking the estimation value of the optical constant of each layer as the actual value of the optical constant. According to the application, the same coefficient is multiplied by the same material layer in the film, the actual values of the optical constant and the thickness of each layer of the film are fitted, and the actual values of the calculated thickness and optical constant are more accurate.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of thin film measurement, and particularly relates to a method and device for obtaining thin film parameters, a terminal device and a computer readable storage medium. BACKGROUND

[0002] Ellipsometry is a surface-sensitive, non-destructive and non-invasive multilayer film measurement technology. It is based on the change of the polarization state of linearly polarized light after reflection by a thin film sample. The thickness and optical constants of the thin film sample are obtained by model fitting. However, in practical applications, the obtained thickness and optical constants are often found to be inaccurate. SUMMARY

[0003] The present application provides a method and device for obtaining thin film parameters, a terminal device and a computer readable storage medium. By multiplying the same material layers in the thin film by the same coefficient, the actual values of the optical constants and thickness of each layer of the thin film are fitted, which can make the calculated actual values of the thickness and optical constants more accurate.

[0004] In a first aspect, the present application provides a method for obtaining thin film parameters, comprising:

[0005] obtaining a function relationship of the thin film, wherein the independent variables of the function relationship include the thickness of each layer of the thin film and the optical constants of each layer, and the dependent variables of the function relationship include the polarization information of the reflected light of the thin film;

[0006] substituting the product of the thickness estimate value of each layer of the thin film and the corresponding coefficient of each layer, and the estimate value of the optical constant of each layer into the function relationship, to calculate the simulation value of the polarization information of the reflected light of the thin film, wherein the coefficients corresponding to the layers of the same material in the thin film are the same;

[0007] when the difference between the simulation value of the polarization information of the reflected light of the thin film and the experimental value of the polarization information of the reflected light of the thin film meets a preset condition, taking the product of the thickness estimate value of each layer of the thin film and the corresponding coefficient of each layer as the actual value of the thickness, and taking the estimate value of the optical constant of each layer of the thin film as the actual value of the optical constant.

[0008] Optionally, after substituting the product of the thickness estimate value of each layer of the thin film and the corresponding coefficient of each layer, and the estimate value of the optical constant of each layer into the function relationship, to calculate the simulation value of the polarization information of the reflected light of the thin film, the method for obtaining thin film parameters further comprises:

[0009] when the difference between the simulation value of the polarization information of the reflected light of the thin film and the experimental value of the polarization information of the reflected light of the thin film does not meet the preset condition, adjusting the thickness estimate value of each layer of the thin film, the corresponding coefficient of each layer and the estimate value of the optical constant of each layer;

[0010] determining the adjusted thickness estimation value of each layer as a new thickness estimation value of each layer, determining the adjusted coefficient corresponding to each layer as a new coefficient corresponding to each layer, and determining the adjusted estimation value of the optical constant of each layer as a new estimation value of the optical constant of each layer, and returning to perform the step of substituting the product of the thickness estimation value of each layer of the thin film and the coefficient corresponding to each layer and the estimation value of the optical constant of each layer into the functional relationship to calculate the simulation value of the reflected light polarization information of the thin film.

[0011] Optionally, the adjusting of the thickness estimation value of each layer of the thin film, the coefficient corresponding to each layer and the estimation value of the optical constant of each layer comprises:

[0012] The thickness estimation value of each layer of the thin film, the coefficient corresponding to each layer and the estimation value of the optical constant of each layer are adjusted by using the gradient descent method.

[0013] Optionally, the preset condition comprises that the difference between the simulation value and the experimental value of the reflected light polarization information is less than an error threshold.

[0014] Optionally, the reflected light polarization information comprises N, C and S.

[0015] Wherein, N=cos2Ψ, C=sin2ΨcosΔ, S=sin2ΨsinΔ.

[0016] Ψ represents the amplitude ratio angle of the reflected light of the elliptically polarized light on the surface of the thin film, and Δ represents the phase difference angle of the reflected light of the elliptically polarized light on the surface of the thin film.

[0017] Optionally, before substituting the product of the thickness estimation value of each layer of the thin film and the coefficient corresponding to each layer and the estimation value of the optical constant of each layer into the functional relationship to calculate the simulation value of the reflected light polarization information of the thin film, the method for obtaining the parameters of the thin film further comprises:

[0018] Obtaining material information of materials used in each layer of the thin film;

[0019] According to the material information, determining the layers of the same material in the thin film.

[0020] Optionally, the optical constant comprises the refractive index and the dielectric constant.

[0021] In a second aspect, the present application provides a device for obtaining the parameters of a thin film, comprising:

[0022] A relationship obtaining unit is configured to obtain a functional relationship of the thin film, wherein the independent variable of the functional relationship comprises the thickness of each layer of the thin film and the optical constant of each layer, and the dependent variable of the functional relationship comprises the reflected light polarization information of the thin film.

[0023] The estimation value calculation unit calculates a simulation value of the reflected light polarization information of the thin film by substituting the product of the thickness estimation value of each layer of the thin film and the corresponding coefficient of each layer and the estimation value of the optical constant of each layer into a function relationship formula, wherein the coefficients corresponding to the layers of the same material in the thin film are the same;

[0024] The actual value determination unit substitutes the product of the thickness estimation value of each layer of the thin film and the corresponding coefficient of each layer as the thickness actual value and substitutes the estimation value of the optical constant of each layer of the thin film as the optical constant actual value when the difference between the simulation value of the reflected light polarization information of the thin film and the experimental value of the reflected light polarization information of the thin film meets a preset condition.

[0025] In a third aspect, the present application provides a terminal device, which comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements the steps of the method of the first aspect when executing the computer program.

[0026] In a fourth aspect, the present application provides a computer readable storage medium, which stores a computer program, and the computer program implements the steps of the method of the first aspect when executed by a processor.

[0027] In a fifth aspect, the present application provides a computer program product, which comprises a computer program, and the computer program implements the steps of the method of the first aspect when executed by one or more processors.

[0028] Compared with the prior art, the present application has the following beneficial effects: the function relationship formula (i.e., the established model) of the to-be-measured thin film is first obtained, then the product of the thickness estimation value of each layer of the thin film and the corresponding coefficient of each layer and the estimation value of the optical constant are substituted into the function relationship formula, and the simulation value of the reflected light polarization information of the thin film can be obtained, and when the difference between the simulation value of the reflected light polarization information of the thin film and the experimental value of the reflected light polarization information of the thin film meets a preset condition, the product of the thickness estimation value of each layer of the thin film and the corresponding coefficient of each layer is substituted as the thickness actual value, and the estimation value of the optical constant of each layer of the thin film is substituted as the optical constant actual value. Different from the related art, the present application considers that the expansion characteristics of the layers of the same material are the same, and therefore the layers of the same material in the thin film are multiplied by the same coefficient, and the actual values of the optical constant and the thickness of each layer of the thin film are fitted by the product, so that the actual values of the calculated thickness and the optical constant are more accurate.

[0029] It can be understood that the beneficial effects of the second aspect to the fifth aspect can be understood with reference to the above description, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0031] Figure 1 is a schematic diagram of an application environment of the thin film parameter acquisition method provided by the embodiments of the present application;

[0032] Figure 2 is a schematic diagram of an implementation flow of the thin film parameter acquisition method provided by the embodiments of the present application;

[0033] Figure 3 is a schematic diagram of a thin film parameter acquisition device provided by the embodiments of the present application;

[0034] Figure 4 is a structural block diagram of a terminal device provided by the embodiments of the present application. DETAILED DESCRIPTION

[0035] In the following description, specific details such as specific system structures, techniques, etc. are presented in order to thoroughly understand the embodiments of the present application. However, it should be clear to those skilled in the art that the present application can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits and methods are omitted to avoid unnecessary details that hinder the description of the present application.

[0036] In order to illustrate the technical solutions proposed in the embodiments of the present application, the following will be described through specific embodiments.

[0037] The application environment of a thin film parameter acquisition method provided by the embodiments of the present application will be described below. Please refer to Figure 1 The application environment of the thin film parameter acquisition method includes:

[0038] An ellipsometer, the ellipsometer includes a light source and a detector, wherein the light source is used to emit light. The light emitted by the light source is reflected by the thin film sample and received by the detector. The detector is used to analyze the received reflected light to obtain an ellipsometric spectrum.

[0039] A computer, the computer can be connected with the ellipsometer, and is used to obtain the thickness and optical constants of the thin film sample by fitting the model of the thin film sample according to the ellipsometric spectrum output by the ellipsometer.

[0040] Specifically, the ellipsometry is a surface-sensitive, non-destructive and non-invasive multilayer film measurement technology, which is based on the change of the polarization state of linearly polarized light after being reflected by a thin film sample, and the thickness and optical constants of the thin film sample are obtained by model fitting. The specific measurement principle is as follows: when the light is incident on the thin film sample, the reflected light changes after multiple reflections and transmissions. First, the ellipsometry of the reflected light of the thin film sample can be detected by a detector, wherein the ellipsometry can be represented by the amplitude ratio angle Ψ and the phase difference angle Δ. Generally, after the amplitude ratio angle Ψ and the phase difference angle Δ are measured, Ψ and Δ are converted into N = cos2Ψ, C = sin2ΨcosΔ, and S = sin2ΨsinΔ. Then, a model of the thin film sample needs to be constructed based on the materials and stacking order of each layer of the thin film sample. By continuously changing the optical constants and thickness in the model, the difference between the theoretical N, C, S output by the model and the N, C, S measured above is minimized, so as to fit the more accurate thickness and optical constants of the thin film.

[0041] A method for obtaining thin film parameters provided by an embodiment of the present application is described below. Please refer to Figure 2 The method for obtaining thin film parameters can be applied to Figure 1 a computer. The method for obtaining thin film parameters includes:

[0042] Step 201: obtaining a function relationship of a thin film.

[0043] Step 202: substituting the product of the thickness estimation value of each layer of the thin film and the corresponding coefficient of each layer and the estimation value of the optical constant of each layer into the function relationship to calculate the simulation value of the reflected light polarization information of the thin film.

[0044] Step 203: when the difference between the simulation value of the reflected light polarization information of the thin film and the experimental value of the reflected light polarization information of the thin film meets a preset condition, the product of the thickness estimation value of each layer of the thin film and the corresponding coefficient of each layer is taken as the actual value of the thickness, and the estimation value of the optical constant of each layer of the thin film is taken as the actual value of the optical constant.

[0045] In the embodiment of the present application, the independent variables of the function relationship of the thin film include the thickness of each layer of the thin film and the optical constant of each layer of the thin film. The dependent variable of the function relationship of the thin film includes the reflected light polarization information of the thin film. The reflected light polarization information is used to represent the change of the reflected light polarization of the thin film. The thin film includes multiple layers, and a user establishes the function relationship of the thin film according to the stacking order of each layer of the thin film. Then, the user can input the constructed function relationship into the computer. The estimation value of the thickness of each layer of the thin film and the estimation value of the optical constant can be the estimation value input by the user into the computer, or the estimation value generated by the computer itself. The experimental value of the reflected light polarization information of the thin film is obtained by Figure 1a value of the reflected light polarization information detected by the ellipsometer in the

[0046] The computer can substitute the product of the thickness estimate of each layer of the thin film and the corresponding coefficient of each layer and the optical constant estimate of each layer of the thin film into the function relationship to calculate the simulation value of the reflected light polarization information of the thin film. Alternatively, the computer can perform step 202 only once to obtain the simulation value of the reflected light polarization information that satisfies the preset condition. If the simulation value of the reflected light polarization information that satisfies the preset condition cannot be obtained by performing step 202 only once, step 202 can be performed more than twice, and different thickness estimates, coefficients, and optical constant estimates are substituted into the function relationship each time to obtain the simulation value of the reflected light polarization information that satisfies the preset condition. It should be noted that the product of the thickness estimate of the thin film and the coefficient substituted into the function relationship each time satisfies the following condition: the coefficients corresponding to the layers of the same material of the thin film are the same. In the process of manufacturing the thin film sample, the same material under the same manufacturing process has the same expansion characteristics, and therefore the layers of the same material of the thin film have the same constraint, which can be represented by the coefficient. For example, the coefficients corresponding to the two layers of material P in the thin film are both 1.2, and the coefficients corresponding to the three layers of material Q in the thin film are all 1.3. The thickness actual value and the optical constant actual value obtained by fitting the product of the thickness estimate of each layer and the coefficient corresponding to each layer are more accurate.

[0047] When the difference between the simulation value of the reflected light polarization information of the thin film obtained by performing step 202 and the experimental value satisfies the preset condition, the product of the thickness estimate of each layer of the thin film and the coefficient corresponding to each layer substituted into the function relationship can be used as the thickness actual value, and the optical constant estimate of each layer of the thin film can be used as the optical constant actual value.

[0048] In some embodiments, the preset condition can be that the difference between the simulation value of the reflected light polarization information of the thin film and the experimental value of the reflected light polarization information of the thin film is less than a preset error threshold. That is, when the simulation value of the reflected light polarization information obtained by calculation is close to the experimental value of the reflected light polarization information, the product of the thickness estimate and the coefficient substituted into the function relationship and the optical constant estimate can be determined as the actual value.

[0049] In some embodiments, the preset condition can be that the difference between the simulated value of the reflected light polarization information and the experimental value of the reflected light polarization information calculated in one of the multiple times of performing step 202 is the smallest among the differences between the simulated value of the reflected light polarization information and the experimental value of the reflected light polarization information calculated in the multiple times of performing step 202. For example, assuming that step 202 is performed three times, the simulated value of the reflected light polarization information calculated in the first time of performing step 202 is a1, the simulated value of the reflected light polarization information calculated in the second time of performing step 202 is a2, and the simulated value of the reflected light polarization information calculated in the third time of performing step 202 is a3. Assuming that the experimental value of the reflected light polarization information is b, if the difference between a3 and b is smaller than the differences between a1 and b and between a2 and b, the product of the thickness estimation value and the coefficient of the function relationship and the optical constant estimation value in the third time can be determined as the actual values.

[0050] Optionally, in order to determine the actual values of the thickness and the optical constant more quickly, after each time of performing step 202, the above-mentioned obtaining method further comprises:

[0051] When the difference between the simulated value of the reflected light polarization information of the thin film and the experimental value of the reflected light polarization information of the thin film does not satisfy the preset condition, the thickness estimation value of each layer of the thin film, the corresponding coefficient of each layer, and the estimation value of the optical constant of each layer are adjusted.

[0052] The adjusted thickness estimation value of each layer is determined as the new thickness estimation value of each layer, the adjusted corresponding coefficient of each layer is determined as the new corresponding coefficient of each layer, the adjusted estimation value of the optical constant of each layer is determined as the new estimation value of the optical constant of each layer, and the step 202 is returned to be performed.

[0053] In the embodiments of the present application, if the difference between the simulation value of the reflected light polarization information of the film obtained by the present calculation and the experimental value of the reflected light polarization information of the film does not satisfy the preset condition, the thickness estimation value, the coefficient and the optical constant estimation value substituted into the functional relationship formula can be adjusted, the adjusted estimation value of the thickness of each layer is determined as the new estimation value of the thickness of each layer, the adjusted coefficient corresponding to each layer is determined as the new coefficient corresponding to each layer, and the adjusted estimation value of the optical constant of each layer is determined as the new estimation value of the optical constant of each layer, and then step 202 is re-executed. Among them, the new coefficient corresponding to each layer still satisfies: the coefficients corresponding to the layers of the same material are the same. It should be understood that when step 202 is re-executed, the product of the new estimation value of the thickness of each layer of the film and the new coefficient and the new estimation value of the optical constant of each layer are substituted into the functional relationship formula to obtain a new simulation value of the reflected light polarization information. If the difference between the new simulation value of the reflected light polarization information and the experimental value of the reflected light polarization information satisfies the preset condition, the product of the new estimation value of the thickness of each layer of the film and the new coefficient is taken as the actual value of the thickness, and the new estimation value of the optical constant of each layer is taken as the actual value of the optical constant. If the difference between the new simulation value of the reflected light polarization information and the experimental value of the reflected light polarization information does not satisfy the preset condition, the new estimation value of the thickness of each layer of the film, the new coefficient and the new estimation value of the optical constant of each layer are adjusted, and so on. In the embodiments of the present application, since the new estimation value is obtained by adjusting the estimation value of the thickness of each layer of the film, the new coefficient and the estimation value of the optical constant of each layer, it can help users obtain the actual value of the thickness and the actual value of the optical constant more quickly.

[0054] It should be noted that when the computer executes step 202 for the first time, the computer can take the value of the thickness of each layer of the film input by the user as the estimation value of the thickness of each layer of the film, take the value of the optical constant of each layer of the film input by the user as the estimation value of the optical constant of each layer, and initialize the coefficient to 1. For example, the user can input the designed thickness value before making the film into the computer, or can input the thickness value observed by an electron microscope into the computer, which is not limited here. Among them, the optical constant of each layer of the film is related to the material used in the layer, and the user can obtain the optical constant value of each layer from the Internet or a paper, and then input the optical constant value into the computer. It should be understood that since the film making method is different, the optical constant value obtained from the Internet or the paper may not be completely accurate, but can only be used as a reference.

[0055] In some embodiments, in order to determine the actual value of the thickness and the actual value of the optical constant more quickly, the above adjustment of the thickness estimation value of each layer of the film, the coefficient corresponding to each layer and the estimation value of the optical constant of each layer includes:

[0056] The gradient descent method is used to adjust the thickness estimation value of each layer of the film, the coefficient corresponding to each layer and the estimation value of the optical constant of each layer.

[0057] In this embodiment of the application, starting from the second execution step 202, the estimated values ​​of the thickness of each layer of the thin film, the coefficients of each layer, and the estimated values ​​of the optical constants of each layer can be adjusted based on the difference between the simulated value and the experimental value of the polarization information of the reflected light obtained in the previous calculation, using the gradient descent method, so as to speed up the fitting speed of the thin film model.

[0058] In some embodiments, the polarization information of the reflected light described above may include N, C, and S.

[0059] Among them, N=cos2Ψ, C=sin2ΨcosΔ, and S=sin2ΨsinΔ.

[0060] Ψ represents the amplitude ratio of the reflected light from the thin film surface of elliptically polarized light, and Δ represents the phase difference angle of the reflected light from the thin film surface of elliptically polarized light.

[0061] In some embodiments, the aforementioned optical constants include refractive index and dielectric constant. The refractive index is the ratio of the speed of light in a vacuum to the speed of light in the medium. The higher the refractive index of a material, the stronger its ability to refract incident light. The dielectric constant is a macroscopic physical quantity that comprehensively reflects the polarization properties within a material.

[0062] In some embodiments, in order to determine the coefficients of each layer, the above acquisition method further includes, prior to step 202:

[0063] Obtain material information for the materials used in each layer of the thin film.

[0064] Based on the material information, identify the layers of the same material in the film.

[0065] In the fabrication of thin film samples, materials using the same fabrication process exhibit similar expansion characteristics. Therefore, layers of the same material in the thin film share the same constraints, which can be expressed as coefficients. In this embodiment, material information for each layer of the thin film is first obtained. This material information indicates the material used for the corresponding layer. Based on the material information of each layer, layers using the same material can be identified. Consequently, the coefficients corresponding to layers using the same material can be assigned the same value.

[0066] As can be seen, the scheme provided in the application firstly obtains the functional relationship of the film to be measured (i.e. the established model), then substitutes the product of the thickness estimation value of each layer of the film and the corresponding coefficient of each layer and the estimation value of the optical constant into the functional relationship, so that the simulation value of the reflected light polarization information of the film can be obtained, when the difference between the simulation value of the reflected light polarization information of the film and the experimental value of the reflected light polarization information of the film satisfies the preset condition, the product of the thickness estimation value of each layer of the film and the corresponding coefficient of each layer is taken as the actual value of the thickness, and the estimation value of the optical constant of each layer of the film is taken as the actual value of the optical constant. Unlike the related art, the scheme provided in the application considers that the expansion characteristics of layers of the same material are the same, so the layers of the same material in the film are multiplied by the same coefficient, and the actual values of the optical constant and the thickness of each layer of the film are fitted through the product, so that the actual values of the calculated thickness and the optical constant can be more accurate.

[0067] Corresponding to the method for obtaining the film parameters provided above, the embodiment of the application further provides a device for obtaining film parameters. As shown in Figure 3 The device 300 for obtaining film parameters in the embodiment of the application comprises:

[0068] A relationship obtaining unit 301, configured to obtain a functional relationship of the film, wherein the independent variable of the functional relationship comprises the thickness of each layer of the film and the optical constant of each layer, and the dependent variable of the functional relationship comprises the reflected light polarization information of the film.

[0069] An estimation value calculating unit 302, configured to substitute the product of the thickness estimation value of each layer of the film and the corresponding coefficient of each layer and the estimation value of the optical constant of each layer into the functional relationship, so as to calculate the simulation value of the reflected light polarization information of the film, wherein the coefficients corresponding to the layers of the same material in the film are the same.

[0070] An actual value determining unit 303, configured to, when the difference between the simulation value of the reflected light polarization information of the film and the experimental value of the reflected light polarization information of the film satisfies the preset condition, take the product of the thickness estimation value of each layer of the film and the corresponding coefficient of each layer as the actual value of the thickness, and take the estimation value of the optical constant of each layer of the film as the actual value of the optical constant.

[0071] Optionally, the above device 300 further comprises:

[0072] An adjusting unit, configured to, when the difference between the simulation value of the reflected light polarization information of the film and the experimental value of the reflected light polarization information of the film does not satisfy the preset condition, adjust the thickness estimation value of each layer of the film, the corresponding coefficient of each layer and the estimation value of the optical constant of each layer.

[0073] The new value determination unit is configured to determine the adjusted thickness estimation value of each layer as a new thickness estimation value of each layer, determine the adjusted coefficient corresponding to each layer as a new coefficient corresponding to each layer, and determine the adjusted estimation value of the optical constant of each layer as a new estimation value of the optical constant of each layer, and return to execute the step of substituting the product of the thickness estimation value of each layer of the thin film and the coefficient corresponding to each layer and the estimation value of the optical constant of each layer into the functional relationship formula to calculate the simulation value of the reflected light polarization information of the thin film.

[0074] Optionally, the adjustment unit is specifically configured to adjust the thickness estimation value of each layer of the thin film, the coefficient corresponding to each layer, and the estimation value of the optical constant of each layer by using a gradient descent method.

[0075] Optionally, the preset condition includes that a difference between the simulation value and the experimental value of the reflected light polarization information is less than an error threshold.

[0076] Optionally, the reflected light polarization information includes N, C, and S.

[0077] N = cos2Ψ, C = sin2ΨcosΔ, and S = sin2ΨsinΔ.

[0078] Ψ represents an amplitude ratio angle of the reflected light of the elliptically polarized light on the surface of the thin film, and Δ represents a phase difference angle of the reflected light of the elliptically polarized light on the surface of the thin film.

[0079] Optionally, the obtaining device 300 further includes:

[0080] The material information obtaining unit is configured to obtain material information of a material used in each layer of the thin film.

[0081] The same layer determination unit is configured to determine layers of the same material in the thin film according to the material information.

[0082] Optionally, the optical constant includes a refractive index and a dielectric constant.

[0083] As can be seen from the above, the scheme first obtains a functional relationship formula (i.e., a model established) of a thin film to be measured, then substitutes the product of the thickness estimation value of each layer of the thin film and the coefficient corresponding to each layer and the estimation value of the optical constant into the functional relationship formula to obtain a simulation value of the reflected light polarization information of the thin film, and when a difference between the simulation value of the reflected light polarization information of the thin film and an experimental value of the reflected light polarization information of the thin film satisfies a preset condition, the product of the thickness estimation value of each layer of the thin film and the coefficient corresponding to each layer is taken as an actual value of the thickness, and the estimation value of the optical constant of each layer of the thin film is taken as an actual value of the optical constant. Unlike related technologies, the scheme considers that layers of the same material have the same expansion characteristics, and therefore multiplies the layers of the same material in the thin film by the same coefficient, and obtains actual values of the optical constant and the thickness of each layer of the thin film by fitting the product, which can make the actual values of the calculated thickness and the optical constant more accurate.

[0084] Corresponding to the method for obtaining thin film parameters provided above, this application embodiment also provides a terminal device, which can be... Figure 1 The computer mentioned can also be any other device with computing capabilities. Please see [link to relevant documentation]. Figure 4 The terminal device 4 in this embodiment includes: a memory 401, and one or more processors 402. Figure 4 Only one is shown in the image, along with a computer program stored in memory 401 and executable on the processor. Memory 401 stores software programs and units. The processor 402 executes various functional applications and data processing by running the software programs and units stored in memory 401 to obtain resources corresponding to preset events. Specifically, the processor 402 implements the following by running the aforementioned computer program stored in memory 401: Figure 2 The method for obtaining thin film parameters in the corresponding embodiment.

[0085] It should be understood that, in the embodiments of this application, the processor 402 may be a central processing unit (CPU), but it may also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor, or any conventional processor, etc.

[0086] Memory 401 may include read-only memory and random access memory, and provides instructions and data to processor 402. Some or all of memory 401 may also include non-volatile random access memory. For example, memory 401 may also store device category information.

[0087] Corresponding to the method for obtaining thin film parameters for terminal devices provided above, this application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the following... Figure 2 The steps of the method for obtaining thin film parameters in the corresponding embodiment.

[0088] Corresponding to the method for acquiring the film parameter applied to the terminal device provided above, the embodiment of the present application further provides a computer program product, the computer program product comprises a computer program, the computer program is executed by one or more processors to realize the method for acquiring the film parameter as Figure 2 The steps of the method for acquiring the film parameter in the corresponding embodiment.

[0089] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the above-mentioned division of each functional unit and module is exemplified, and in actual application, the above-mentioned functions can be completed by different functional units and modules according to needs, that is, the internal structure of the above-mentioned device is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or software. In addition, the specific names of each functional unit and module are only for easy distinction, and do not limit the protection scope of the present application. The specific working process of the unit and module in the above system can be referred to the corresponding process in the foregoing method embodiment, which will not be described here.

[0090] In the above embodiments, the description of each embodiment has its own emphasis, and the parts not described or recorded in detail in a certain embodiment can be referred to the related description of other embodiments.

[0091] Those skilled in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized by electronic hardware or a combination of external device software and electronic hardware. Whether the functions are executed in hardware or software depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0092] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the system embodiments described above are only schematic, for example, the division of the above-mentioned modules or units is only a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the displayed or discussed each other can be indirect coupling or communication connection through some interface, device or unit, which can be electrical, mechanical or other forms.

[0093] The units described as separate components above can or can not be physically separate, and the components shown as units can or can not be physical units, i.e., can be located in one place, or can be distributed to multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0094] The integrated units described above, if implemented in the form of software functional units and sold or used as independent products, can be stored in a computer readable storage medium. Based on this understanding, all or part of the processes in the above embodiment methods can also be completed by a computer program instructing associated hardware. The above computer program can be stored in a computer readable storage medium, and when executed by a processor, can implement the steps of the above various method embodiments. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or some intermediate forms, etc. The computer readable storage medium can include any entity or device capable of carrying the above computer program code, recording medium, U disk, mobile hard disk, magnetic disk, optical disk, computer readable memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc. It should be noted that the content included in the above computer readable storage medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction, for example, in some jurisdictions, according to legislation and patent practice, the computer readable storage medium does not include electrical carrier signals and telecommunication signals.

[0095] The above embodiments are only used to illustrate the technical solutions of the present application, rather than limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A method of acquiring film parameters, characterized by, The method comprises the following steps: obtaining a function formula of the thin film, wherein the independent variable of the function formula comprises thicknesses of layers of the thin film and optical constants of the layers, and the dependent variable of the function formula comprises reflected light polarization information of the thin film; multiplying the estimated values of the thicknesses of the layers of the thin film and the corresponding coefficients of the layers, and the estimated values of the optical constants of the layers, and substituting the product into the function formula to obtain simulated values of the reflected light polarization information of the thin film, wherein the coefficients corresponding to layers of the same material in the thin film are the same, and the same constraint exists between the layers of the same material in the thin film, and the constraint is represented by the coefficients; when a difference between the simulated values of the reflected light polarization information of the thin film and experimental values of the reflected light polarization information of the thin film satisfies a preset condition, taking the product of the estimated values of the thicknesses of the layers of the thin film and the corresponding coefficients of the layers as actual values of the thicknesses, and taking the estimated values of the optical constants of the layers of the thin film as actual values of the optical constants; after the step of multiplying the estimated values of the thicknesses of the layers of the thin film and the corresponding coefficients of the layers, and the estimated values of the optical constants of the layers, and substituting the product into the function formula to obtain the simulated values of the reflected light polarization information of the thin film, the method further comprises the following steps: when the difference between the simulated values of the reflected light polarization information of the thin film and the experimental values of the reflected light polarization information of the thin film does not satisfy the preset condition, adjusting the estimated values of the thicknesses of the layers of the thin film, the corresponding coefficients of the layers and the estimated values of the optical constants of the layers; determining the adjusted estimated values of the thicknesses of the layers as new estimated values of the thicknesses of the layers, the adjusted coefficients of the layers as new coefficients of the layers, and the adjusted estimated values of the optical constants of the layers as new estimated values of the optical constants of the layers, and returning to the step of multiplying the estimated values of the thicknesses of the layers of the thin film and the corresponding coefficients of the layers, and the estimated values of the optical constants of the layers, and substituting the product into the function formula to obtain the simulated values of the reflected light polarization information of the thin film; the step of adjusting the estimated values of the thicknesses of the layers of the thin film, the corresponding coefficients of the layers and the estimated values of the optical constants of the layers comprises: adjusting the estimated values of the thicknesses of the layers of the thin film, the corresponding coefficients of the layers and the estimated values of the optical constants of the layers by using a gradient descent method.

2. The method of claim 1, wherein the step of obtaining the film parameters is performed by a method comprising: The preset condition comprises that the difference between the simulated values of the reflected light polarization information and the experimental values is less than an error threshold.

3. The method of claim 2, wherein the step of obtaining the film parameter is performed by a method comprising: The reflected light polarization information comprises N, C and S; wherein N = cos2Ψ, C = sin2ΨcosΔ and S = sin2ΨsinΔ; Ψ represents an amplitude ratio angle of reflected light of elliptically polarized light on a surface of the thin film, and Δ represents a phase difference angle of the reflected light of the elliptically polarized light on the surface of the thin film.

4. The method for obtaining thin film parameters as described in claim 2, characterized in that, Before the step of multiplying the estimated values of the thicknesses of the layers of the thin film and the corresponding coefficients of the layers, and the estimated values of the optical constants of the layers, and substituting the product into the function formula to obtain the simulated values of the reflected light polarization information of the thin film, the method further comprises the following steps: obtaining material information of materials used in the layers of the thin film; determining layers of the same material in the thin film according to the material information.

5. The method for obtaining thin film parameters as described in claim 1, characterized in that, The optical constants comprise refractive indexes and dielectric constants.

6. An apparatus for acquiring film parameters, characterized by The method comprises the following steps: The relationship obtaining unit is configured to obtain a function relationship of the thin film, wherein the independent variable of the function relationship comprises thicknesses of layers of the thin film and optical constants of the layers, and the dependent variable of the function relationship comprises reflected light polarization information of the thin film. The estimated value calculating unit is configured to substitute a product of the thickness estimated values of the layers of the thin film and corresponding coefficients of the layers and estimated values of the optical constants of the layers into the function relationship to calculate an analog value of the reflected light polarization information of the thin film, wherein the coefficients corresponding to layers of the same material in the thin film are the same, and the same constraint exists between the layers of the same material in the thin film, and the constraint is represented by the coefficients. The actual value determining unit is configured to, when a difference between the analog value of the reflected light polarization information of the thin film and an experimental value of the reflected light polarization information of the thin film satisfies a preset condition, take the product of the thickness estimated values of the layers of the thin film and the corresponding coefficients of the layers as thickness actual values and take the estimated values of the optical constants of the layers of the thin film as optical constant actual values. The adjusting unit is configured to, when the difference between the analog value of the reflected light polarization information of the thin film and the experimental value of the reflected light polarization information of the thin film does not satisfy the preset condition, adjust the thickness estimated values of the layers of the thin film, the corresponding coefficients of the layers, and the estimated values of the optical constants of the layers. The new value determining unit is configured to determine the adjusted thickness estimated values of the layers as new thickness estimated values of the layers, determine the adjusted coefficients corresponding to the layers as new coefficients corresponding to the layers, determine the adjusted estimated values of the optical constants of the layers as new estimated values of the optical constants of the layers, and return to execute the step of substituting the product of the thickness estimated values of the layers of the thin film and the corresponding coefficients of the layers and the estimated values of the optical constants of the layers into the function relationship to calculate the analog value of the reflected light polarization information of the thin film. The adjusting unit is specifically configured to adjust the thickness estimated values of the layers of the thin film, the corresponding coefficients of the layers, and the estimated values of the optical constants of the layers by using a gradient descent method.

7. A terminal device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, The computer program is executed by the processor to implement the method in any one of claims 1 to 5.

8. A computer-readable storage medium storing a computer program, the computer-readable storage medium comprising: The computer program is executed by the processor to implement the method in any one of claims 1 to 5.

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