Film thickness measuring method and film thickness measuring device

Abstract

The invention discloses a thin film thickness measuring method and a thin film thickness measuring device.The thin film thickness measuring method is used for detecting the thickness of a thin film on a substrate, the method comprises the steps that electron beams are emitted to the thin film on the substrate, and part of electrons in the electron beams are absorbed by the thin film and the substrate; receiving the other part of residual electrons which are not absorbed by the thin film and the substrate in the electron beam, and detecting a first electric signal of the other part of residual electrons; and calculating the thickness of the thin film according to the first electric signal based on known related parameters of the electron beam, the thin film and the substrate. According to the thin film thickness measuring method, the electron beam is used for measuring the thickness of the thin film, and compared with beta electron energy distribution of a radioactive source, the electron beam is easier to control, convenient to manage, higher in safety, higher in resolution efficiency, wide in application range and suitable for measurement of various thin films.

Description

Technical Field

[0001] The present invention belongs to the technical field of film thickness measurement, and in particular relates to a film thickness measurement method and a film thickness measurement device. Background Art

[0002] Lithium battery manufacturers use a wide variety of coating inspection methods, primarily categorized as contact manual measurement and non-contact instrumentation. Contact manual measurement is subject to numerous factors that influence results and cannot provide real-time monitoring. Non-contact online inspection instruments use photoelectric thickness measurement. Laser thickness gauges are widely used, but they are sensitive to environmental factors, vibration, temperature and humidity, and color, requiring extremely high levels of operation and maintenance.

[0003] In radiographic thickness measurement, depending on the radiation source, radiographic thickness gauges are divided into two types: X-rays and beta rays. In combination with the lithium battery production process and the radiation penetration characteristics and detectability, X-rays are only suitable for anode coating (applicable to aluminum foil), while beta rays can be applied to both cathode and anode coatings. However, radioactive isotopes are strictly controlled, and their application, use, and retirement are very inconvenient and costly. Moreover, since radioactive isotopes cannot be turned off, there are major safety hazards. In addition, the electron energy spectrum of radioactive isotopes is very wide. When used to measure thickness, for the sake of simplicity, the electron energy spectrum is not measured, and only the signal intensity of the electron is measured. However, the measured film and the detector have significant differences in the absorption of electrons of different energies. Therefore, the use of a radioactive source is not conducive to the accurate measurement of coating thickness. In addition, the existing radioactive source thickness measurement device uses a mechanical structure to adjust the position of the radiation source to achieve measurement at different positions, which is inefficient. Summary of the Invention

[0004] The purpose of the embodiments of the present invention is to provide a film thickness measurement method and a film thickness measurement device to solve the problems of using radioactive isotopes to measure film thickness in the prior art, which have safety hazards, high costs, low precision and low efficiency.

[0005] A first embodiment of the present invention provides a method for measuring the thickness of a thin film, for detecting the thickness of a thin film on a substrate, the method comprising:

[0006] emitting an electron beam toward the thin film on the substrate, wherein a portion of electrons in the electron beam is absorbed by the thin film and the substrate;

[0007] receiving another portion of remaining electrons in the electron beam that are not absorbed by the thin film and the substrate, and detecting a first electrical signal of the another portion of remaining electrons;

[0008] The thickness of the film is calculated according to the first electrical signal based on known relevant parameters of the electron beam, the film and the substrate.

[0009] Furthermore, the method of calculating the thickness of the film according to the first electrical signal based on known relevant parameters of the electron beam, the film, and the substrate further includes the following steps:

[0010] Acquiring the thickness of the substrate, the absorption coefficient of the substrate to the electron beam, the absorption coefficient of the thin film to the electron beam, and a second electrical signal before the electron beam bombards the substrate and the thin film;

[0011] The thickness of the thin film is calculated based on the first electrical signal, the second electrical signal, the thickness of the substrate, the absorption coefficient of the substrate to the electron beam, and the absorption coefficient of the thin film to the electron beam.

[0012] Furthermore, the first electrical signal is the beam current intensity formed by the other portion of the remaining electrons, and the second electrical signal is the beam current intensity before the electron beam bombards the substrate and the film.

[0013] Furthermore, when the thin film coated on the substrate is a first thin film, the thickness of the thin film is calculated based on the first electrical signal, the second electrical signal, the thickness of the substrate, the absorption coefficient of the substrate to the electron beam, and the absorption coefficient of the thin film to the electron beam, including the following calculation formula:

[0014]

[0015] Where h1 is the thickness of the first film, h0 is the thickness of the substrate, i=1, 2…n represents the type of electron beam, I i0 is the beam intensity of the i-th electron beam before bombarding the substrate and the first film, I i is the beam intensity after the i-th electron beam bombards the substrate and the first film, mi is the absorption coefficient of the substrate to the i-th electron beam, and ni is the absorption coefficient of the first film to the i-th electron beam.

[0016] Furthermore, when a first thin film and a second thin film are sequentially coated on the substrate, the thickness of the thin film is calculated based on the first electrical signal, the second electrical signal, the thickness of the substrate, the absorption coefficient of the substrate to the electron beam, and the absorption coefficient of the thin film to the electron beam, including the following calculation formula:

[0017]

[0018] Where h1 is the thickness of the first film, h2 is the thickness of the second film, h0 is the thickness of the substrate, i=1, 2…n represents the type of electron beam, I i0 is the beam intensity of the i-th electron beam before bombarding the substrate, the first film and the second film, I iis the beam intensity detected after the i-th electron beam bombards the substrate, the first film and the second film, I ic is the beam intensity calculated after the i-th electron beam bombards the substrate, the first film and the second film, mi is the absorption coefficient of the substrate to the i-th electron beam, ni is the absorption coefficient of the first film to the i-th electron beam, ki is the absorption coefficient of the second film to the i-th electron beam, dI is I ic and I i The set variance of .

[0019] A film thickness measuring device according to an embodiment of the second aspect of the present invention includes:

[0020] an electron gun assembly, configured to emit an electron beam toward the thin film on the substrate, wherein a portion of electrons in the electron beam is absorbed by the thin film and the substrate;

[0021] a detector for receiving another portion of remaining electrons in the electron beam that are not absorbed by the film and the substrate, and detecting a first electrical signal of the another portion of remaining electrons;

[0022] A measurement and control system is connected to the detector and the electron gun assembly respectively. The measurement and control system calculates the thickness of the film according to the first electrical signal based on known relevant parameters of the electron beam, the film and the substrate.

[0023] Furthermore, the measurement and control system includes:

[0024] An input module, configured to input the thickness of the substrate, the absorption coefficient of the substrate to the electron beam, the absorption coefficient of the thin film to the electron beam, and a second electrical signal before the electron beam bombards the substrate and the thin film;

[0025] A calculation module is connected to the input module, and the calculation module calculates the thickness of the film based on the first electrical signal, the second electrical signal, the thickness of the substrate, the absorption coefficient of the substrate to the electron beam, and the absorption coefficient of the film to the electron beam.

[0026] Furthermore, the first electrical signal is the beam current intensity formed by the other portion of the remaining electrons, and the second electrical signal is the beam current intensity before the electron beam bombards the substrate and the film.

[0027] Furthermore, when the thin film coated on the substrate is a first thin film, the thickness of the thin film is calculated based on the first electrical signal, the second electrical signal, the thickness of the substrate, the absorption coefficient of the substrate to the electron beam, and the absorption coefficient of the thin film to the electron beam, including the following calculation formula:

[0028]

[0029] Where h1 is the thickness of the first film, h2 is the thickness of the second film, h0 is the thickness of the substrate, i=1, 2…n represents the type of electron beam, I i0 is the beam intensity of the i-th electron beam before bombarding the substrate and the first film, I i is the beam intensity after the i-th electron beam bombards the substrate and the first film, mi is the absorption coefficient of the substrate to the i-th electron beam, and ni is the absorption coefficient of the first film to the i-th electron beam.

[0030] Furthermore, when a first thin film and a second thin film are sequentially coated on the substrate, the thickness of the thin film is calculated based on the first electrical signal, the second electrical signal, the thickness of the substrate, the absorption coefficient of the substrate to the electron beam, and the absorption coefficient of the thin film to the electron beam, including the following calculation formula:

[0031]

[0032] Where h1 is the thickness of the first film, h0 is the thickness of the substrate, i=1, 2…n represents the type of electron beam, I i0 is the beam intensity of the i-th electron beam before bombarding the substrate, the first film and the second film, I i is the beam intensity detected after the i-th electron beam bombards the substrate, the first film and the second film, I ic is the beam intensity calculated after the i-th electron beam bombards the substrate, the first film and the second film, mi is the absorption coefficient of the substrate to the i-th electron beam, ni is the absorption coefficient of the first film to the i-th electron beam, ki is the absorption coefficient of the second film to the i-th electron beam, dI is I ic and I i The set variance of .

[0033] According to the film thickness measurement method of the embodiment of the present invention, the film thickness is measured using an electron beam. Compared with the β electron energy distribution of the radioactive source, the electron beam is easier to control and manage, has high safety, higher resolution efficiency, and a wide range of applications, and is suitable for measuring various types of films. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a flow chart of a thin film thickness measurement method according to an embodiment of the present invention;

[0035] Figure 2 is another flow chart of a thin film thickness measurement method according to an embodiment of the present invention;

[0036] Figure 3 is a schematic diagram of a film thickness measuring device according to an embodiment of the present invention;

[0037] Figure 44 is a schematic block diagram of a measurement and control system in a film thickness measurement device according to an embodiment of the present invention.

[0038] Reference numerals

[0039] Film thickness measuring device 100;

[0040] Electron gun assembly 10; electron gun 11; electron gun power supply 12;

[0041] Detector 20;

[0042] Measurement and control system 30; input module 31; calculation module 32;

[0043] Substrate 200; film 300. DETAILED DESCRIPTION

[0044] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0045] The terms "first," "second," and the like in the specification and claims of the present invention are used to distinguish similar objects and are not intended to describe a particular order or precedence. It should be understood that such terms are interchangeable where appropriate, so that embodiments of the present invention can be implemented in sequences other than those illustrated or described herein. Furthermore, the term "and / or" in the specification and claims refers to at least one of the connected objects, and the character " / " generally indicates that the connected objects are in an "or" relationship.

[0046] The following combination Figures 1 to 4 , the method for measuring the thickness of the film 300 provided by the embodiment of the present invention is described in detail through specific embodiments and application scenarios.

[0047] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0048] The method for measuring the thickness of the film 300 according to an embodiment of the present invention is used to detect the thickness of the film 300 on the substrate 200, such as Figure 1 and Figure 3 As shown, the method includes the following steps:

[0049] Step S10: emitting an electron beam toward the thin film 300 on the substrate 200, wherein a portion of electrons in the electron beam is absorbed by the thin film 300 and the substrate 200;

[0050] Step S20: receiving another portion of remaining electrons in the electron beam that are not absorbed by the film 300 and the substrate 200, and converting the received another portion of remaining electrons into a corresponding first electrical signal;

[0051] Step S30 : Based on the known relevant parameters of the electron beam, the thin film 300 , and the substrate 200 , the thickness of the thin film 300 is calculated according to the first electrical signal.

[0052] Specifically, a film thickness measuring device 100 having an electron gun 11 is used to measure the thickness of a film 300 on a substrate 200. First, the electron gun 11 generates an electron beam, which replaces the beta electrons emitted by beta decay radioisotopes and serves as an electron source for measuring coating thickness and even surface density. After the incident electron beam bombards the substrate 200 and the film 300, a portion of the electrons are absorbed, and the remaining electrons are received by the detector 20 and generate a first electrical signal. The thickness of the film 300 is calculated using the relationship between the first electrical signal and the thickness. Using the electron gun 11 to emit an electron beam to measure the thickness of the film 300 has the following advantages:

[0053] First, the electron gun 11 can only work when it is powered on, which is safer to use and simpler to manage than a radioactive source; second, compared with the β electron energy distribution of a radioactive source, the electron gun 11 can provide monoenergetic electrons, the dependence of the detection signal on the thickness of the film 300 is simpler, the data analysis rate is higher, and it is more suitable for the needs of rapid analysis of the production line; in addition, compared with the β electron energy distribution of a radioactive source, the driving voltage can be flexibly changed to adjust the energy of the electron beam, which is suitable for the measurement of various thin films 300; for multi-layer films, the electron beam energy can be adjusted quickly and in steps to achieve precise measurement of the thickness of the multi-layer film 300; finally, the electron beam energy generated by the electron gun 11 at any time is single, so the electron beam can be accurately scanned to different positions of the film 300 for thickness measurement by electromagnetic field deflection, which is faster and more efficient than screw adjustment.

[0054] Therefore, according to the method for measuring the thickness of the thin film 300 according to an embodiment of the present invention, an electron beam is used to measure the thickness of the thin film 300. Compared with the β electron energy distribution of the radiation source, the electron beam is easier to control, convenient to manage, safer, has higher resolution efficiency, and has a wide range of applications. It is suitable for measuring various types of thin films 300.

[0055] According to one embodiment of the present invention, Figure 2 As shown, step S30 further includes the following steps:

[0056] Step S31, obtaining the thickness of the substrate 200, the absorption coefficient of the substrate 200 to the electron beam, the absorption coefficient of the film 300 to the electron beam, and the second electrical signal before the electron beam bombards the substrate 200 and the film 300;

[0057] Step S32 : calculating the thickness of the thin film 300 based on the first electrical signal, the second electrical signal, the thickness of the substrate 200 , the absorption coefficient of the substrate 200 to the electron beam, and the absorption coefficient of the thin film 300 to the electron beam.

[0058] That is to say, in order to calculate the thickness of the film 300, it is necessary to obtain known parameters such as the first electrical signal, the second electrical signal, the thickness of the substrate 200, the absorption coefficient of the substrate 200 to the electron beam, and the absorption coefficient of the film 300 to the electron beam. These parameters can be pre-set or calibrated. For example, the second electrical signal and the thickness of the substrate 200 can be pre-set or directly measured, and the absorption coefficient of the substrate 200 to the electron beam and the absorption coefficient of the film 300 to the electron beam can be calibrated through simulation or experiment.

[0059] Furthermore, the first electrical signal is the beam current intensity formed by another portion of the remaining electrons, and the second electrical signal is the beam current intensity before the electron beam bombards the substrate 200 and the film 300 .

[0060] According to one embodiment of the present invention, when the thin film 300 coated on the substrate 200 is a first thin film, the thickness of the thin film 300 is calculated based on the first electrical signal, the second electrical signal, the thickness of the substrate 200, the absorption coefficient of the substrate 200 to the electron beam, and the absorption coefficient of the thin film 300 to the electron beam, including the following calculation formula:

[0061]

[0062] Wherein, h1 is the thickness of the first film, h0 is the thickness of the substrate 200, i is the type of electron beam (i=1, 2...n), I i0 is the beam intensity of the i-th electron beam before bombarding the substrate 200 and the first film, I i is the beam intensity after the i-th electron beam bombards the substrate 200 and the first film, mi is the absorption coefficient of the substrate 200 to the i-th electron beam, and ni is the absorption coefficient of the first film to the i-th electron beam.

[0063] It should be noted that, for the measurement of the thickness of a single film on the substrate 200, the thickness h1 of the first film to be measured can be directly solved by the above formula, wherein h0 is the known thickness of the substrate 200, and i is the type of electron beam (i=1, 2...n). In order to improve the measurement accuracy, the electron beam current intensity (i.e., the second electrical signal I0 and the first electrical signal I) can be measured before and after bombarding the coating. For any set i-th electron beam energy E i , the corresponding detection signal strength I can be measured i0 and I i. mi and ki are the absorption coefficients of each layer of the thin film 300 to the electron energy of the current gear, respectively. A thin film 300 of standard thickness can be used for calibration in advance according to the same arrangement. According to another embodiment of the present invention, when the first thin film and the second thin film are coated on the substrate 200 in sequence, the thickness of the thin film 300 is calculated based on the first electrical signal, the second electrical signal, the thickness of the substrate 200, the absorption coefficient of the substrate 200 to the electron beam, and the absorption coefficient of the thin film 300 to the electron beam, including the following calculation formula:

[0064]

[0065] Wherein, h1 is the thickness of the first film, h2 is the thickness of the second film, h0 is the thickness of the substrate 200, i is the type of electron beam (i=1, 2...n), I i0 is the beam intensity of the i-th electron beam before bombarding the substrate 200, the first film and the second film, I i is the beam intensity detected after the i-th electron beam bombards the substrate 200, the first film and the second film, I ic is the beam intensity calculated after the i-th electron beam bombards the substrate 200, the first film and the second film, mi is the absorption coefficient of the substrate 200 to the i-th electron beam, ni is the absorption coefficient of the first film to the i-th electron beam, ki is the absorption coefficient of the second film to the i-th electron beam, dI is I ic and I i The set variance of .

[0066] Among them, mi, ni and ki can be calibrated in advance using a film 300 of standard thickness in the same arrangement. For a double-layer film or even a multi-layer film, by collecting the signal intensity at different energies, an artificial intelligence method is used to randomly sample each layer of the film 300 until the variance dI of the calculated detection signal and the measured detection signal is less than a given threshold. Among them, I ic is the calculated value of the first signal after attenuation by the film 300, I i The thickness measurement accuracy can be improved by calculating the variance dI using electron beams with multiple energy levels (i=1, 2...n).

[0067] The variance formula dI is derived as follows:

[0068]

[0069] …

[0070]

[0071]

[0072] The film thickness measuring device 100 according to the second embodiment of the present invention is used to detect the thickness of a film 300 on a substrate 200. Figure 3 As shown, the film thickness measuring device 100 includes an electron gun assembly 10 , a detector 20 and a measurement and control system 30 .

[0073] Specifically, the electron gun assembly 10 is used to emit an electron beam to the thin film 300 on the substrate 200, and a portion of the electrons in the electron beam are absorbed by the thin film 300 and the substrate 200; the detector 20 is used to receive the other portion of the remaining electrons in the electron beam that are not absorbed by the thin film 300 and the substrate 200, and convert the received other portion of the remaining electrons into a corresponding first electrical signal; the measurement and control system 30 is connected to the detector 20, and the measurement and control system 30 calculates the thickness of the thin film 300 based on the first electrical signal.

[0074] In other words, if Figure 2 As shown, the film thickness measuring device 100 is composed of an electron gun 11 assembly, a detector 20 and a measurement and control system 30. The electron gun 11 assembly is composed of an electron gun power supply 12 and an electron gun 11. The electron gun power supply 12 drives the electron gun 11 to generate an electron beam, which is accelerated by high voltage to an energy e i The electron gun 11 has a foil window that isolates the atmosphere and vacuum. The electron beam penetrates the foil window and bombards the film 300 to be measured. A part of the electrons is absorbed by the film 300 and the substrate 200, and the remaining electrons enter the detector 20 to generate a first electrical signal. The measurement and control system 30 records the first electrical signal and analyzes the thickness of the film 300.

[0075] Further, if Figure 4 As shown, the measurement and control system 30 includes an input module 31 and a calculation module 32 .

[0076] Specifically, the input module 31 is used to input the thickness of the substrate 200, the absorption coefficient of the substrate 200 to the electron beam, the absorption coefficient of the thin film 300 to the electron beam, and the second electrical signal before the electron beam bombards the substrate 200 and the thin film 300; the calculation module 32 calculates the thickness of the thin film 300 based on the first electrical signal, the second electrical signal, the thickness of the substrate 200, the absorption coefficient of the substrate 200 to the electron beam, and the absorption coefficient of the thin film 300 to the electron beam.

[0077] In order to calculate the thickness of the film 300, it is necessary to obtain known parameters such as the first electrical signal, the second electrical signal, the thickness of the substrate 200, the absorption coefficient of the substrate 200 to the electron beam, and the absorption coefficient of the film 300 to the electron beam. These parameters can be pre-set or calibrated. For example, the second electrical signal and the thickness of the substrate 200 can be pre-set or directly measured, and the absorption coefficient of the substrate 200 to the electron beam and the absorption coefficient of the film 300 to the electron beam can be calibrated through simulation or experiment.

[0078] Furthermore, the first electrical signal is the beam current intensity formed by another portion of the remaining electrons, and the second electrical signal is the beam current intensity before the electron beam bombards the substrate 200 and the film 300 .

[0079] According to one embodiment of the present invention, when the thin film 300 coated on the substrate 200 is a first thin film, the thickness of the thin film 300 is calculated based on the first electrical signal, the second electrical signal, the thickness of the substrate 200, the absorption coefficient of the substrate 200 to the electron beam, and the absorption coefficient of the thin film 300 to the electron beam, including the following calculation formula:

[0080]

[0081] Wherein, h1 is the thickness of the first film, h0 is the thickness of the substrate 200, i is the type of electron beam (i=1, 2...n), I i0 is the beam intensity of the i-th electron beam before bombarding the substrate 200 and the first film, I i is the beam intensity after the i-th electron beam bombards the substrate 200 and the first film, mi is the absorption coefficient of the substrate 200 to the i-th electron beam, and ni is the absorption coefficient of the first film to the i-th electron beam.

[0082] It should be noted that, for the measurement of the thickness of a single film on the substrate 200, the thickness h1 of the first film to be measured can be directly solved by the above formula, wherein h0 is the known thickness of the substrate 200, and i is the type of electron beam (i=1, 2...n). In order to improve the measurement accuracy, the electron beam current intensity (i.e., the second electrical signal I0 and the first electrical signal I) can be measured before and after bombarding the coating. For any set i-th electron beam energy E i , the corresponding detection signal strength I i0 and I i Mi and Ki are the absorption coefficients of each layer of the film 300 to the electron energy of the current gear, and can be calibrated in advance using a film 300 of standard thickness in the same arrangement.

[0083] According to another embodiment of the present invention, when the first thin film and the second thin film are sequentially coated on the substrate 200, the thickness of the thin film 300 is calculated based on the first electrical signal, the second electrical signal, the thickness of the substrate 200, the absorption coefficient of the substrate 200 to the electron beam, and the absorption coefficient of the thin film 300 to the electron beam, including the following calculation formula:

[0084]

[0085] Wherein, h1 is the thickness of the first film, h2 is the thickness of the second film, h0 is the thickness of the substrate 200, i is the type of electron beam (i=1, 2...n), I i0is the beam intensity of the i-th electron beam before bombarding the substrate 200, the first film and the second film, I i is the beam intensity detected after the i-th electron beam bombards the substrate 200, the first film and the second film, I ic is the beam intensity calculated after the i-th electron beam bombards the substrate 200, the first film and the second film, mi is the absorption coefficient of the substrate 200 to the i-th electron beam, ni is the absorption coefficient of the first film to the i-th electron beam, ki is the absorption coefficient of the second film to the i-th electron beam, dI is I ic and I i The set variance of .

[0086] Among them, mi, ni and ki can be calibrated in advance using a film 300 of standard thickness in the same arrangement. For a double-layer film or even a multi-layer film, by collecting the signal intensity at different energies, an artificial intelligence method is used to randomly sample each layer of the film 300 until the variance dI of the calculated detection signal and the measured detection signal is less than a given threshold. Among them, I ic is the calculated value of the first signal after attenuation by the film 300, I i The thickness measurement accuracy can be improved by calculating the variance dI using electron beams with multiple energy levels (i=1, 2...n).

[0087] The variance formula dI is derived as follows:

[0088]

[0089] …

[0090]

[0091]

[0092] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are protected by the present invention.

Claims

1. A method for measuring film thickness, for detecting the thickness of a film on a substrate, characterized in that: The method comprises: emitting an electron beam toward the thin film on the substrate, wherein a portion of electrons in the electron beam is absorbed by the thin film and the substrate; receiving another portion of remaining electrons in the electron beam that are not absorbed by the thin film and the substrate, and detecting a first electrical signal of the another portion of remaining electrons; The thickness of the film is calculated according to the first electrical signal based on known relevant parameters of the electron beam, the film and the substrate.

2. The film thickness measurement method according to claim 1, characterized in that: The method of calculating the thickness of the film according to the first electrical signal based on known relevant parameters of the electron beam, the film, and the substrate further includes the following steps: Acquiring the thickness of the substrate, the absorption coefficient of the substrate to the electron beam, the absorption coefficient of the thin film to the electron beam, and a second electrical signal before the electron beam bombards the substrate and the thin film; The thickness of the thin film is calculated based on the first electrical signal, the second electrical signal, the thickness of the substrate, the absorption coefficient of the substrate to the electron beam, and the absorption coefficient of the thin film to the electron beam.

3. The film thickness measurement method according to claim 2, characterized in that: The first electrical signal is the beam current intensity formed by the other portion of the remaining electrons, and the second electrical signal is the beam current intensity before the electron beam bombards the substrate and the film.

4. The film thickness measurement method according to claim 3, characterized in that: When the thin film coated on the substrate is a first thin film, the thickness of the thin film is calculated based on the first electrical signal, the second electrical signal, the thickness of the substrate, the absorption coefficient of the substrate to the electron beam, and the absorption coefficient of the thin film to the electron beam, including the following calculation formula: Where h1 is the thickness of the first film, h0 is the thickness of the substrate, i=1, 2…n represents the type of electron beam, I i0 is the beam intensity of the i-th electron beam before bombarding the substrate and the first film, I i is the beam intensity after the i-th electron beam bombards the substrate and the first film, mi is the absorption coefficient of the substrate to the i-th electron beam, and ni is the absorption coefficient of the first film to the i-th electron beam.

5. The film thickness measurement method according to claim 3, characterized in that: When a first thin film and a second thin film are sequentially coated on the substrate, the thickness of the thin film is calculated based on the first electrical signal, the second electrical signal, the thickness of the substrate, the absorption coefficient of the substrate to the electron beam, and the absorption coefficient of the thin film to the electron beam, including the following calculation formula: Where h1 is the thickness of the first film, h2 is the thickness of the second film, h0 is the thickness of the substrate, i=1, 2…n represents the type of electron beam, I i0 is the beam intensity of the i-th electron beam before bombarding the substrate, the first film and the second film, I i is the beam intensity detected after the i-th electron beam bombards the substrate, the first film and the second film, I ic is the beam intensity calculated after the i-th electron beam bombards the substrate, the first film and the second film, mi is the absorption coefficient of the substrate to the i-th electron beam, ni is the absorption coefficient of the first film to the i-th electron beam, ki is the absorption coefficient of the second film to the i-th electron beam, dI is I ic and I i The set variance of .

6. A film thickness measuring device for detecting the thickness of a film on a substrate, characterized in that: The device comprises: an electron gun assembly, configured to emit an electron beam toward the thin film on the substrate, wherein a portion of electrons in the electron beam is absorbed by the thin film and the substrate; a detector for receiving another portion of remaining electrons in the electron beam that are not absorbed by the film and the substrate, and detecting a first electrical signal of the another portion of remaining electrons; A measurement and control system is connected to the detector and the electron gun assembly respectively. The measurement and control system calculates the thickness of the film according to the first electrical signal based on known relevant parameters of the electron beam, the film and the substrate.

7. The thin film thickness measuring device according to claim 6, characterized in that: The measurement and control system comprises: An input module, configured to input the thickness of the substrate, the absorption coefficient of the substrate to the electron beam, the absorption coefficient of the thin film to the electron beam, and a second electrical signal before the electron beam bombards the substrate and the thin film; A calculation module is connected to the input module, and the calculation module calculates the thickness of the film based on the first electrical signal, the second electrical signal, the thickness of the substrate, the absorption coefficient of the substrate to the electron beam, and the absorption coefficient of the film to the electron beam.

8. The thin film thickness measuring device according to claim 7, characterized in that: The first electrical signal is the beam current intensity formed by the other portion of the remaining electrons, and the second electrical signal is the beam current intensity before the electron beam bombards the substrate and the film.

9. The thin film thickness measuring device according to claim 8, characterized in that: When the thin film coated on the substrate is a first thin film, the thickness of the thin film is calculated based on the first electrical signal, the second electrical signal, the thickness of the substrate, the absorption coefficient of the substrate to the electron beam, and the absorption coefficient of the thin film to the electron beam, including the following calculation formula: Where h1 is the thickness of the first film, h0 is the thickness of the substrate, i=1, 2…n represents the type of electron beam, I i0 is the beam intensity of the i-th electron beam before bombarding the substrate and the first film, I i is the beam intensity after the i-th electron beam bombards the substrate and the first film, mi is the absorption coefficient of the substrate to the i-th electron beam, and ni is the absorption coefficient of the first film to the i-th electron beam.

10. The thin film thickness measuring device according to claim 8, characterized in that: When a first thin film and a second thin film are sequentially coated on the substrate, the thickness of the thin film is calculated based on the first electrical signal, the second electrical signal, the thickness of the substrate, the absorption coefficient of the substrate to the electron beam, and the absorption coefficient of the thin film to the electron beam, including the following calculation formula: Where h1 is the thickness of the first film, h2 is the thickness of the second film, h0 is the thickness of the substrate, i=1, 2…n represents the type of electron beam, I i0 is the beam intensity of the i-th electron beam before bombarding the substrate, the first film and the second film, I i is the beam intensity detected after the i-th electron beam bombards the substrate, the first film and the second film, I ic is the beam intensity calculated after the i-th electron beam bombards the substrate, the first film and the second film, mi is the absorption coefficient of the substrate to the i-th electron beam, ni is the absorption coefficient of the first film to the i-th electron beam, ki is the absorption coefficient of the second film to the i-th electron beam, dI is I ic and I i The set variance of .

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