Method and apparatus for measuring the thickness of a film on a suede silicon substrate

Abstract

The application relates to the technical field of thin film thickness measurement, in particular to a method and equipment for measuring the thickness of a thin film on a suede silicon substrate, which comprises the following steps: at least one light beam is vertically incident on the surface of a thin film sample and receives a reflected light beam; the position of the thin film sample is adjusted so that the thin film sample is at a suitable test coordinate and angle; under the suitable test coordinate and angle, the first position where the incident light beam is incident on the surface of the thin film sample is set as a first position, another position where the incident light beam is incident on the surface of the thin film sample after being reflected is set as a second position, the incident light intensity and effective incident light intensity at the first position are determined; the reflectivity, transmissivity and reflected light intensity of the light beam at the first position are calculated, and the theoretical reflectivity and actual reflectivity at the second position are calculated based on the reflectivity, transmissivity and reflected light intensity, and finally the thickness of the measured thin film is obtained by substituting the theoretical formula. The application has the effect of improving the accuracy of the measurement result.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of thin film thickness measurement, and in particular to a method and device for measuring the thickness of a thin film on a textured silicon substrate. BACKGROUND

[0002] Currently, the field of optical measurement technology is developing rapidly, especially in the semiconductor manufacturing and photovoltaic industries, where accurate measurement of thin film thickness is particularly important. Such measurement not only concerns product quality, but also significantly improves production process efficiency and reduces costs. In related technologies, referring to Figure 1 , the film thickness measurement method typically uses a light source to emit incident light to a thin film sample 6, such that the incident light is perpendicular to the thin film sample 6 and is reflected by the upper and lower surfaces of the thin film sample 6 to produce two reflected lights. When the two reflected lights meet in space, they will interfere due to the same amplitude and frequency, and then the reflectivity is calculated to determine the film thickness. Specifically, the reflectivity can be calculated according to the Fresnel formula. For normal incidence, the reflection coefficient r and the transmission coefficient t can be expressed as follows:

[0003]

[0004] where r and t are complex numbers containing amplitude and phase information. n1 is the refractive index of air, and n2 is the refractive index of the thin film. The reflectivity can be calculated from r and t, and the thin film thickness can be calculated from the reflectivity:

[0005]

[0006] In view of the related technologies in the above, in the photovoltaic industry, in order to improve the light trapping of silicon wafers, the silicon wafers are usually treated with alkali to achieve texturing, and finally a pyramid-shaped textured surface is obtained. In subsequent processes, other thin films need to be deposited on the textured silicon wafers. Since the textured silicon surface has significant roughness, it does not conform to the assumption of a smooth surface in the Fresnel formula. Therefore, inaccurate measurement results are prone to occur. SUMMARY

[0007] In order to improve the accuracy of the measurement results, the present application provides a method and device for measuring the thickness of a thin film on a textured silicon substrate.

[0008] In a first aspect, the present application provides a method for measuring the thickness of a thin film on a textured silicon substrate, which adopts the following technical solution:

[0009] A method for measuring the thickness of a thin film on a textured silicon substrate, comprising the following steps:

[0010] At least one light beam is vertically incident on the surface of the thin film sample and receives the reflected light beam;

[0011] Adjusting the position of the film sample, so that the film sample is in a suitable test coordinates and angles;

[0012] Setting the position of the first incident light beam to the surface of the film sample as the first position, and the position of the reflected light beam to the surface of the film sample as the second position, determining the incident light intensity and the effective incident light intensity at the first position;

[0013] Calculating the reflectivity, transmissivity and reflected light intensity of the light beam at the first position, and calculating the theoretical reflectivity and actual reflectivity at the second position based on the above, and finally substituting into the theoretical formula to obtain the thickness of the film to be measured.

[0014] By using the above technical solution, the reflectivity at the first position and the second position is calculated, and the result is substituted into the theoretical formula to calculate the thickness of the film to be measured, which realizes accurate analysis and processing of complex reflection and refraction phenomenon, thereby facilitating accurate measurement of the thickness of the film of suede silicon and other samples with complex surface morphology, and further facilitating improvement of the accuracy of the measurement result.

[0015] Optionally, the incident light intensity at the first position is set as , and the effective incident light intensity is , then the effective incident light intensity calculation formula is as follows: .

[0016] Optionally, the reflectivity of the light beam at the first position is calculated, and the specific steps are as follows: according to the Fresnel formula and the transfer matrix method, the Fresnel formula is:

[0017] ;

[0018] and , , and satisfy the following relationship:

[0019] ;

[0020] The transfer matrix method is:

[0021] ;

[0022] ;

[0023] ;

[0024] ;

[0025] ;

[0026] wherein, is the reflection coefficient of s-wave, is the reflection coefficient of p-wave, is the refractive index of the incident medium, is the refractive index of the transmission medium, is the incident angle, is the refractive angle, is the characteristic matrix of each layer of the multi-layer film, and These elements describe the phase change and amplitude change of the light wave in the medium; and Also describe the phase and amplitude change, but corresponding to different polarization or propagation direction; is the phase thickness, which describes the phase difference accumulated when the light wave propagates in the medium; is the thickness of the film, and λ is the wavelength, is the wave vector component, is the transmission matrix of the entire multi-layer film, is the reflectivity at the first position.

[0027] By using the above technical solutions, the reflectivity and transmissivity of the light beam at the first position are calculated by using the Fresnel formula and the transmission matrix method, which can accurately analyze the complex reflection and refraction phenomenon, thereby improving the accuracy of the measurement of the thickness of the film on the suede silicon substrate.

[0028] Optionally, the calculation formula for calculating the reflected light intensity at the first position is as follows:

[0029] wherein, is the reflected light intensity at the first position.

[0030] Optionally, the Fresnel formula and the transmission matrix method can be encapsulated as a function: Then, the calculation formula of the theoretical reflectivity and the actual reflectivity at the second position is as follows:

[0031] ;

[0032] ;

[0033] wherein, is a parameter, is the thickness value of each layer, is the range of the thickness value of each layer, is the theoretical reflectivity, is the reflected light intensity actually measured at the second position, is the reflectivity calculated at the second position, is the incident angle of the incident light at the second position.

[0034] Optionally, the theoretical formula is:

[0035]

[0036] wherein, is the starting position of the calculated wavelength, is the ending position of the calculated wavelength, wherein the specific step is related to the parameter setting of the spectrometer and the accuracy required for calculation, through the calculation of the above formula, a function for evaluating the similarity degree between the calculated reflectivity curve and the theoretical reflectivity curve is obtained, then all thickness values in the thickness range are calculated, each thickness value can obtain a corresponding value, all values are combined to obtain an array about all thickness values, and the minimum value is taken, and the thickness value corresponding to the minimum value is the film thickness.

[0037] Optionally, .

[0038] In a second aspect, the application provides a thin film thickness measurement device on a textured silicon substrate, which is used to realize the thin film thickness measurement method on the textured silicon substrate, and adopts the following technical scheme:

[0039] A thin film thickness measurement device on a textured silicon substrate comprises:

[0040] a light source;

[0041] two spectrometers, one of which is connected with an incident light probe through an optical fiber, the incident light probe is connected with the light source through an optical fiber, and the other one is connected with a reflected light probe through an optical fiber, and the light source can emit a light beam through the incident light probe;

[0042] a sample moving table, on which a thin film sample is placed, and the sample moving table can adjust the angle and position of the thin film sample;

[0043] a lower computer, which is connected with the two spectrometers respectively.

[0044] ​By adopting the technical scheme, when the film thickness needs to be measured, the film sample is first placed on the sample moving table, and then the light source is started to make the incident light probe emit light and make the light vertically incident on the film sample surface. At this time, the reflected light probe receives the reflected light and transmits the received light signal to the spectrometer, so that the spectrometer obtains the spectrum data and transmits the spectrum data to the lower computer. In this process, the sample moving table can drive the film sample to rotate horizontally by a certain angle, and the spectrometer can collect signals after the film sample rotates by a certain angle each time, so as to facilitate the lower computer to process the spectrum data to find the test angle and test coordinates corresponding to the maximum value, and then facilitate the calculation of the thickness of the film to be measured according to the data measured at the test angle and test coordinates.

[0045] Optionally, a box body is included, and the light source, the incident light probe, the reflected light probe and the sample moving table are arranged in the box body.

[0046] By adopting the technical scheme, the light source, the incident light probe, the reflected light probe and the sample moving table are integrated in a box body to form a sealed structure, which effectively eliminates the interference of external light and improves the measurement accuracy and stability.

[0047] Optionally, an included angle between the incident light probe and the horizontal plane of the film sample is 90 degrees, and an included angle between the reflected light probe and the horizontal plane of the film sample is 50-52 degrees.

[0048] In summary, the present application has the following at least one beneficial technical effect:

[0049] 1. By constructing a special optical model and adopting an advanced calculation method, accurate analysis and processing of complex reflection and refraction phenomena are realized, thereby facilitating accurate measurement of the thickness of the film on the suede silicon surface, and thereby facilitating improvement of the measurement accuracy and reliability;

[0050] 2. By integrating the light source, the spectrometer, the probe and the sample moving table in a box body, the interference of external light is effectively eliminated, and the measurement accuracy is improved. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1 is a reflection schematic diagram of incident light vertically incident on a film sample in the related art.

[0052] Figure 2 is a whole structure schematic diagram of a film thickness measurement device on a suede silicon substrate in an embodiment of the present application.

[0053] Figure 3 is a reflection and refraction schematic diagram of an incident light beam on a film sample in an embodiment of the present application.

[0054] Figure 4 is a schematic diagram of partial reflection and refraction of an incident light beam on a thin film sample in the embodiment of the present application.

[0055] Legend:

[0056] 1, spectrometer; 11, incident light probe; 12, reflected light probe; 2, lower computer; 3, light source; 31, incident light beam; 32, first reflected light; 33, second reflected light; 34, third reflected light; 35, fourth reflected light; 36, fifth reflected light; 37, sixth reflected light; 4, sample moving table; 5, box; 6, thin film sample; 61, first position; 62, second position. DETAILED DESCRIPTION

[0057] The following will be described in detail in combination with the accompanying Figures 1-4 The present application is further described in detail.

[0058] The embodiment of the present application discloses a method for measuring the thickness of a thin film on a suede silicon substrate.

[0059] It should be noted that in the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0060] Referring to Figure 2 A method for measuring the thickness of a thin film on a suede silicon substrate, comprising the following steps:

[0061] Before performing the thickness measurement, the preparation work needs to be done, and the specific steps are as follows:

[0062] A spectrometer 1 is used to collect standard spectrum data and dark spectrum data, and another spectrometer is used to collect dark spectrum data, and the collected data is uploaded to the lower computer 2. In this process, the test coordinates and test angles of the thin film sample 6 are constantly adjusted, and the spectrum signal is analyzed by the lower computer 2 to find the test coordinates and test angles corresponding to the maximum value.

[0063] The film optical parameters are imported into the lower computer 2, and the specific steps are as follows: according to the film system structure constructed by the user, the optical parameters of each layer are derived, including the wavelength array lamb, the complex refractive index array nk_list of the film, and the array nk_list contains the wavelength and complex refractive index relationship of each layer material, and the thickness array d_list is obtained in the same way. The following provides a specific example of optical parameters:

[0064] lamb = [ 200 300 …… 1100];

[0065] nk_list = [[2.31+0.57j 1.55+0.j ] [2.18+0.03j 1.51+0.j ]

[0066] ……[1.30+0.01j 1.44 +0.j]];

[0067] d_list = [ 200 200];

[0068] d_range_list = [[50, 1000] [50, 1000]].

[0069] Referring to Figure 2 and Figure 3 , after the preparation work is completed, the measurement stage is entered, and the specific steps are as follows:

[0070] At least one light beam is vertically incident on the surface of the film sample 6, and the reflected light probe 12 is used to receive the reflected light beam.

[0071] Adjust the position of the film sample 6 so that the film sample 6 is at a suitable test coordinate and angle.

[0072] Set the position where the incident light beam 31 first enters the surface of the film sample 6 as the first position 61 under the suitable test coordinate and angle, and the other position where the incident light beam 31 enters the surface of the film sample 6 after reflection as the second position 62.

[0073] When the light beam is vertically incident to the surface of the thin film sample 6, the incident light beam 31 is reflected and refracted at the first position 61 to form a first reflected light 32, and the refracted light is reflected at the interface between the thin film and silicon, and is refracted at the interface between the thin film and air to leave the thin film to form a second reflected light 33. The first reflected light 32 and the second reflected light 33 are incident to the second position 62 at the same time, and are reflected and refracted at the second position 62, so that the first reflected light 32 forms a third reflected light 34 by reflection and forms a fourth reflected light 35 by refraction, and the second reflected light 33 forms a fifth reflected light 36 by reflection and forms a sixth reflected light 37 by refraction, thereby facilitating the reflection light probe 12 to receive the first reflected light 32, the second reflected light 33, the third reflected light 34, the fourth reflected light 35, the fifth reflected light 36 and the sixth reflected light 37.

[0074] In summary, the fourth reflected light 35, the fifth reflected light 36 and the sixth reflected light 37 satisfy the interference condition, so that the received spectral data can be analyzed by constructing a suitable optical model to analyze the film thickness information of the thin film sample 6.

[0075] It should be noted that when the incident light beam 31 is incident to the surface of the thin film sample 6, the spot area formed by the incident light beam 31 on the surface of the thin film sample 6 is larger than the area of a single pyramid on the surface of the thin film sample 6, and the reflection directions of the reflected light of the four faces of the pyramid are different, so that the reflection light probe 12 can only receive the reflected light of one face of the pyramid.

[0076] The incident light intensity at the first position 61 is set to , and the effective incident light intensity is , The acquisition can be obtained by a white board or other standard sample, and the incident light intensity can be measured by a light source and a spectrometer 1. It can be understood that the incident light is vertically incident on the "pyramid", and in the current algorithm, only the incident light of one face of the "pyramid" participates in the calculation, and the effective incident light intensity calculation formula is as follows: .

[0077] It should be noted that the value calculated by the effective incident light intensity calculation formula is an approximate value.

[0078] Referring to Figure 3 and Figure 4 , according to the Fresnel formula and the transfer matrix method, the reflectivity of the light beam at the first position 61 is calculated, and the specific steps are as follows:

[0079] For non-vertical incident s wave and p wave, according to the Fresnel formula, the reflection coefficients are respectively:

[0080] ;

[0081] wherein, is the reflection coefficient of s-wave, is the reflection coefficient of p-wave, is the refractive index of incident medium, is the refractive index of transmission medium, is the incident angle, is the refraction angle. And , , and satisfy the following relationship:

[0082]

[0083] According to the transfer matrix method, for each layer of the multilayer film, a characteristic matrix can be constructed according to the refractive index, thickness and incident angle of the layer, and the specific construction formula is as follows:

[0084] ;

[0085] ;

[0086] ;

[0087] wherein, is the characteristic matrix of each layer of the multilayer film, and These elements describe the phase change and amplitude change of the light wave in the medium. and Also describe the phase and amplitude changes, but correspond to different polarizations or propagation directions. is the phase thickness, which describes the phase difference accumulated when the light wave propagates in the medium. is the thickness of the film, λ is the wavelength, is the refractive index of the medium, is the wave vector component, which is related to the propagation direction and refractive index of the light wave in the medium, and is used to describe the reflection and transmission characteristics of the light wave on the interface of the medium.

[0088] After obtaining the characteristic matrix of each layer, the characteristic matrices are multiplied in order to obtain the transfer matrix of the entire multilayer film, and the calculation formula is as follows:

[0089]

[0090] wherein, is the transfer matrix of the entire multilayer film, M 1 ，M 2 ，.....，MN are the characteristic matrices of each layer in the multilayer film, respectively. Then, the reflectivity at the first position 61 is calculated by The calculation formula is as follows:

[0091] ;

[0092] The above formula can be encapsulated as a function: . Wherein, is a parameter, which is a fixed value; is the thickness value of each layer, which is an unknown quantity; is the range of the thickness value of each layer. And contains the initial incident angle , the list of refractive index , the list of extinction coefficient , which can be expressed as: .

[0093] Referring to Figure 3 and Figure 4 , then the reflected light intensity at the first position 61 is calculated, and the calculation formula is as follows:

[0094] ;

[0095] Wherein, is the reflected light intensity at the first position.

[0096] According to the reflected light intensity at the first position 61, the theoretical reflectivity at the second position 62 can be calculated, and the calculation formula is as follows:

[0097] ;

[0098] Wherein, is the theoretical reflectivity, is the actual measured reflected light intensity at the second position 62.

[0099] If the structure of the first position 61 and the second position 62 of the thin film sample 6 is completely the same, the reflectivity coefficient and the transmittance coefficient at the second position 62 are the same as those at the first position 61, so when the actual reflectivity at the second position 62 needs to be calculated, the function at the first position 61 can be directly called, and the calculation formula is as follows:

[0100] ;

[0101] Wherein, is the reflectivity calculated at the second position 62, is the incident angle of the incident light at the second position 62.

[0102] ​In this embodiment, the incident angle of the incident light at the first position 61 is , and =54.74 0 ; the incident angle at the second position 62 is = 15.78°, and the specific derivation process is as follows:

[0103] ∠θ3 =90 0 -(180 0 -∠γ-∠β)

[0104] ∠β = 180°-2*∠θ1

[0105] ∠γ = 90°-∠θ1

[0106] Therefore, ∠θ3 = 180°-3*∠θ1.

[0107] Finally, by calculating the reflectivity under different wavelengths and substituting the calculated values into the theoretical formula, the thickness value of the thin film sample 6 can be obtained, and the specific theoretical formula is as follows:

[0108] ;

[0109] wherein, is the starting position of the calculated wavelength, is the end position of the calculated wavelength, and the specific step is related to the parameter setting of the spectrometer and the required accuracy of the calculation. Through the calculation of the above formula, a function for evaluating the similarity between the calculated reflectivity curve and the theoretical reflectivity curve can be obtained. Then, all thickness values in the thickness range are calculated, and each thickness value can obtain a corresponding value. By combining all values, an array about all thickness values is obtained, and the minimum value is taken, and the thickness value corresponding to the minimum value is the thickness of the thin film.

[0110] The embodiment of the application also discloses a thin film thickness measurement device on a textured silicon substrate, which is used to realize the thin film thickness measurement method on the textured silicon substrate.

[0111] Referring to Figure 2 , a thin film thickness measurement device on a textured silicon substrate includes a spectrometer 1, a lower computer 2, a light source 3, a sample moving table 4, and a box body 5. The spectrometer 1 and the lower computer 2 are respectively arranged outside the box body 5, and the spectrometer 1 is provided with two spectrometers 1, which are electrically connected with the lower computer 2, so that the spectrometer 1 can conveniently transmit the spectral signal to the lower computer 2, and the lower computer 2 is used for receiving and sending signals and processing the signals.

[0112] The spectrometer 1 is provided with an SMA905 interface for connecting optical fibers, one spectrometer 1 is connected with an incident light probe 11 through an optical fiber for calibrating incident light intensity information; another spectrometer 1 is connected with a reflected light probe 12 through an optical fiber for receiving light intensity information reflected at the second position 62. The incident light probe 11 and the reflected light probe 12 are respectively installed in the box 5.

[0113] The light source 3 and the sample moving table 4 are respectively installed in the box 5, so as to facilitate the exclusion of external light interference and improve the measurement accuracy and stability. The incident light probe 11 is connected with the light source 3 through an optical fiber, and the optical fiber and the light source 3 also adopt an SMA905 interface, and the wavelength range can be selected.

[0114] The sample moving table 4 is placed with a thin film sample 6. In the embodiment, the sample moving table 4 can drive the thin film sample 6 to move horizontally and rotate, so as to facilitate the adjustment of the angle and coordinates of the thin film sample 6, so as to facilitate the measurement of the thin film sample 6 at different angles and coordinates.

[0115] It should be noted that the specific structure of the sample moving table 4 belongs to the conventional technical means for those skilled in the art, and therefore will not be described in detail in the embodiment of the present application.

[0116] When the thin film sample 6 is placed on the sample moving table 4, the included angle between the incident light probe 11 and the horizontal plane of the thin film sample 6 is 90 degrees, and the distance between the incident light probe 11 and the thin film sample 6 is 5-10 mm, so as to ensure that the light is perpendicular to the incident. At this time, the included angle between the reflected light probe 12 and the horizontal plane of the thin film sample 6 is 50-52 degrees, and the distance between the reflected light probe 12 and the thin film sample 6 is 5-10 mm, so as to facilitate the reflected light probe 12 to receive the reflected light at a specific angle. In the embodiment, the included angle between the reflected light probe 12 and the horizontal plane of the thin film sample 6 is 51 degrees.

[0117] The implementation principle of the thin film thickness measurement device on the suede silicon substrate according to the embodiment of the present application is that when the thickness of the thin film sample 6 needs to be measured, the light source 3 emits a light beam to the thin film sample 6 through the incident light probe 11, so that the light beam is perpendicular to the incident of the thin film sample 6. At this time, the reflected light probe 12 can receive the reflected light and transmit it to the spectrometer 1, so as to facilitate the spectrometer 1 to convert the light signal into spectrum data and transmit the spectrum data to the lower computer 2, and then facilitate the lower computer 2 to complete the thickness calculation according to the measurement data, so as to measure the thickness of the thin film.

[0118] The above are the preferred embodiments of the present application, which do not limit the protection scope of the present application, therefore: any equivalent changes made on the structure, shape, principle of the present application shall be covered within the protection scope of the present application.

Claims

1. A method for measuring the thickness of a thin film on a textured silicon substrate, characterized in that, Includes the following steps: At least one beam of light is incident perpendicularly onto the surface of the thin film sample (6) and the reflected beam is received. The surface of the thin film sample (6) has a pyramid-shaped textured surface. Adjust the position of the thin film sample (6) so that the thin film sample (6) is in a suitable test coordinate and angle; Under appropriate test coordinates and angles, the position where the incident light beam (31) first incidents onto the surface of the thin film sample (6) is the first position (61), and the other position where the incident light beam (31) incident onto the surface of the thin film sample (6) after reflection is the second position (62). The incident light intensity and effective incident light intensity at the first position (61) are determined. Calculate the reflectivity, transmittance, and reflected light intensity of the light beam at the first position (61), and calculate the theoretical reflectivity and actual reflectivity at the second position (62) based on these values. Finally, substitute these values ​​into the theoretical formula to obtain the thickness of the film to be measured.

2. The method for measuring the thickness of a thin film on a textured silicon substrate according to claim 1, characterized in that: The incident light intensity at the first position (61) is set to... The effective incident light intensity is The formula for calculating the effective incident light intensity is as follows: .

3. The method for measuring the thickness of a thin film on a textured silicon substrate according to claim 2, characterized in that: The specific steps for calculating the reflectivity of the beam at the first position (61) are as follows: According to the Fresnel formula and the transmission matrix method, the Fresnel formula is: ； and , , and The following relationship must be satisfied: ； The transfer matrix method is as follows: ； ； ； ； ； in, The reflection coefficient of the S-wave. The reflection coefficient of the p-wave. Let be the refractive index of the incident medium. Let be the refractive index of the transmission medium. Angle of incidence For the angle of refraction, For each layer of the multilayer film, and These elements describe the phase and amplitude changes of light waves in the medium; and It also describes phase and amplitude changes, but corresponds to different polarizations or propagation directions; Phase thickness describes the phase difference accumulated as a light wave propagates in a medium; Let λ be the thickness of the thin film and λ be the wavelength. For wave vector components, This represents the transport matrix of the entire multilayer film. The reflectance is at the first position (61).

4. The method for measuring the thickness of a thin film on a textured silicon substrate according to claim 3, characterized in that: The formula for calculating the intensity of reflected light at the first position (61) is as follows: ； in, The intensity of the reflected light at the first position (61) is denoted as .

5. The method for measuring the thickness of a thin film on a textured silicon substrate according to claim 4, characterized in that: Let Fresnel's formula and the transfer matrix method be encapsulated as functions: The formulas for calculating the theoretical reflectance and actual reflectance at the second position (62) are as follows: ； ； in, For parameters, For the thickness value of each layer, The range of thickness values ​​for each layer. For the second position (62), the theoretical reflectivity is processed. The intensity of reflected light actually measured at the second position (62) The reflectance calculated at the second position (62), The incident angle of the incident light at the second position (62).

6. The method for measuring the thickness of a thin film on a textured silicon substrate according to claim 5, characterized in that: The theoretical formula is as follows: ； in, The starting position of the calculated wavelength, The calculated wavelength termination position is given, where the specific step size depends on the spectrometer parameter settings and the required calculation accuracy. The above formula yields a function that evaluates the similarity between the calculated reflectance curve and the theoretical reflectance curve. Then, calculations are performed for all thickness values ​​within the thickness range, and a corresponding value is obtained for each thickness value. Values, merge all This yields an array containing all thickness values. Take the minimum value, and the thickness corresponding to the minimum value is the film thickness.

7. The method for measuring the thickness of a thin film on a textured silicon substrate according to claim 5, characterized in that: 。 8. A device for measuring the thickness of a thin film on a textured silicon substrate, used in the method for measuring the thickness of a thin film on a textured silicon substrate as described in any one of claims 1-7, characterized in that, include: Light source (3); The spectrometer (1) is provided in two parts. One spectrometer (1) is connected to an incident light probe (11) via an optical fiber. The incident light probe (11) is connected to the light source (3) via an optical fiber. The other spectrometer (1) is connected to a reflected light probe (12) via an optical fiber. The light source (3) can emit a light beam through the incident light probe (11). A sample moving stage (4) is provided, on which a thin film sample (6) is placed. The sample moving stage (4) is capable of adjusting the angle and position of the thin film sample (6). The lower-level machine (2) is connected to the two spectrometers (1) respectively.

9. The thin film thickness measuring device on a textured silicon substrate according to claim 8, characterized in that: The container includes a housing (5), and the light source (3), the incident light probe (11), the reflected light probe (12) and the sample moving stage (4) are respectively disposed inside the housing (5).

10. The thin film thickness measuring device on a textured silicon substrate according to claim 8, characterized in that: The angle between the incident light probe (11) and the horizontal plane of the thin film sample (6) is 90 degrees, and the angle between the reflected light probe (12) and the horizontal plane of the thin film sample (6) is 50-52 degrees.

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