Method for measuring the thickness of an ultrathin film material

Abstract

This application relates to a method for measuring the thickness of ultrathin film materials, comprising: acquiring surface mass spectra on the surfaces of the ultrathin film and the substrate using a single ion source to determine the characteristic ion peaks of the ultrathin film and the substrate; selecting an etchable micro-region, etching the ultrathin film using a sputtering ion source, alternating the etching and spectral acquisition processes until the characteristic ion peaks of the substrate appear and their intensity stabilizes, thus completing the etched micro-region; repeating the etching to form multiple spaced target etched micro-regions; placing the sample in a profilometer, controlling the probe to move on the surface of the micro-region, recording the depth curve of the etched pits, reading the thickness of multiple micro-regions and taking the average value to obtain the thickness of the ultrathin film. This method is applicable to polymer ultrathin films with a thickness of 1-200 nm and substrates of glass, ITO, silicon wafers, or mica. Through uniform etching and multi-point averaging, the accuracy and repeatability of film thickness measurement are improved.

Description

Technical Field

[0001] This application relates to the field of film thickness measurement technology, and in particular to a method for measuring the thickness of ultrathin film materials. Background Technology

[0002] Polymer ultrathin films typically refer to polymer material layers with thicknesses ranging from submicron to nanometer scales. They have wide applications in cutting-edge fields such as microelectromechanical systems, flexible electronic devices, and panel displays. In these applications, polymer films not only serve as functional coatings but also play roles such as physical separation, selective permeability, and adhesion.

[0003] Time-of-flight secondary ion mass spectrometry (TOF-SIMS) is a surface-sensitive analytical technique that provides information on the chemical composition, spatial distribution of ions, and depth along a material surface. It has gained widespread attention in the characterization of polymer thin films in recent years. This technique utilizes a focused primary ion beam to bombard the sample surface and collects the secondary ions generated by sputtering. By measuring their time of flight, the mass-to-charge ratio is determined, thereby identifying the surface chemical composition. Furthermore, the depth analysis function of TOF-SIMS involves introducing another ion source (a sputtered ion source) between the spectral acquisition intervals to etch the sample layer by layer, alternating between etching and spectral acquisition to obtain a curve showing the change in film composition with depth, i.e., a depth profile. As etching progresses, an etch pit of a certain depth is eventually formed on the film surface.

[0004] Theoretically, the depth of the etch pit reflects the thickness of the removed film. Therefore, measuring this depth is crucial for obtaining film thickness information using TOF-SIMS depth analysis technology. Existing literature mentions measuring the depth of the etch pit as the film thickness and further calculating the sputtering rate by the ratio of this thickness to sputtering time. This method is significant for the application of TOF-SIMS technology: firstly, it can be used to calibrate the sputtering rate of sputtered ions under specific conditions on standard samples to evaluate the operational stability of the equipment; secondly, the calibrated sputtering rate can be used to estimate the film thickness of unknown materials.

[0005] In practice, the application of this method faces several technical challenges. First, compared to inorganic materials, organic polymer materials are more sensitive to ion beam bombardment. During profilometry measurements, there are some factors that affect the accuracy of the results. For samples with uneven etched boundaries or poor step quality, the repeatability and stability of the measurement results are often difficult to guarantee.

[0006] Based on the above situation, there is a need to provide an improved method for measuring the etching depth of polymer ultrathin films, in order to solve the problem of film thickness measurement uncertainty caused by factors such as increased surface roughness after etching and difficulty in measurement positioning in the existing technology. Summary of the Invention

[0007] The purpose of this application is to provide a method for measuring the thickness of ultrathin film materials, to solve the problems in the prior art where the surface of polymer ultrathin films is rough after etching due to their sensitivity to ion beam sputtering, and the uncertainty in depth measurement using a profilometer, thereby improving the accuracy and repeatability of film thickness measurement and making it applicable to various types of polymer ultrathin films. This purpose is achieved through the following technical solution: The method for measuring the thickness of ultrathin film materials in this application includes the following steps: Surface mass spectra were collected on the ultrafilm and substrate surfaces using a primary ion source to determine the characteristic ion peaks of the ultrafilm and substrate. Select an etching micro-region, use a sputtering ion source to etch the ultrathin film, and alternate the etching and spectral sampling processes until the characteristic ion peaks of the substrate appear and the ion intensity remains unchanged, thus completing the etching micro-region. Repeat the etching micro-region process to form multiple target etched micro-regions arranged at intervals. The sample is placed in a profilometer, and the probe is controlled to move on the surface of the micro-region. As the probe moves, the depth curve of the etched pit is recorded, and the thickness of multiple target etched micro-regions is read. The average value is taken as the thickness of the etched micro-region, and the film thickness of the polymer ultrathin film is obtained.

[0008] In one embodiment, the sputtering ion source is an argon ion source, an argon cluster ion source, a C60 ion source, or a cesium ion source.

[0009] In one embodiment, the etching operation voltage is in the range of 1kV-20kV, the current is in the range of 0.1nA-20nA, and the etching time is in the range of 1s-30s.

[0010] In one embodiment, the side length of the etched micro-region is in the range of 10 μm to 500 μm.

[0011] In one embodiment, the spacing between adjacent target etched micro-regions is in the range of 10 μm to 500 μm.

[0012] In one embodiment, the number of target etched micro-regions is greater than or equal to 3.

[0013] In one embodiment, the substrate is glass, ITO, silicon wafer, or mica.

[0014] In one embodiment, the thickness of the ultrathin film is in the range of 1 nm to 200 nm.

[0015] In one embodiment, the probe moves in a direction parallel to one edge of the etched micro-region.

[0016] In one embodiment, the probe moves at a speed in the range of 20 μm / s to 100 μm / s.

[0017] Compared with the prior art, this application has the following beneficial effects: This application reduces the random errors introduced by single-point measurements by forming multiple spaced-apart target etched micro-regions and measuring the depth of multiple etched pits using a profilometer, and then averaging the results. This improves the accuracy and repeatability of film thickness measurement. The profilometer itself has no special requirements regarding the reflectivity, type, or hardness of the material being measured. Combined with the material universality of TOF-SIMS depth analysis technology, this method can meet the thickness characterization needs of polymer ultrathin films in different systems.

[0018] This method, during TOF-SIMS depth analysis, controls the operating parameters of the sputtering ion source (e.g., voltage 1-20 kV, current 0.1-20 nA, etching time 1-30 s) and ensures that the sputtering ion source does not damage the periphery of the micro-region, thereby forming a uniformly etched micro-region on the surface of the polymer ultrathin film. The uniform etch morphology provides a high-quality sample basis for accurate subsequent profilometry measurements. The method has a clear operational procedure, does not rely on the operator's subjective experience, and provides an objective and reliable measurement method for the thickness characterization of polymer ultrathin films. Attached Figure Description

[0019] Figure 1 This is a flowchart illustrating a method for measuring the thickness of an ultrathin film material in one embodiment of this application. Detailed Implementation

[0020] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, it should be noted that, for ease of description, only the parts relevant to this application are shown in the accompanying drawings, not the entire structure. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0021] The terms “comprising” and “having”, and any variations thereof, used in this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0022] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0023] When performing depth analysis of polymer ultrathin films using TOF-SIMS technology, the etching effect of the sputtering ion source directly affects the feasibility of subsequent depth measurements. Polymer materials are highly sensitive to ion beam bombardment; if etching parameters are inappropriately selected or the morphology of the etched area is uneven, the etched film surface often fails to form a smooth and clear step. This makes it difficult for the profilometer to accurately identify the boundaries and bottoms of the etched pits, thus affecting the reliability of the thickness readings. To address these technical problems, this application controls the etching process conditions to form uniformly shaped etched micro-regions on the surface of the polymer ultrathin film. Multiple spaced etched micro-regions are then used for multi-point measurements, and the average value is taken to reduce the random errors that may be introduced by a single measurement, thereby obtaining more objective and stable film thickness data.

[0024] The technical solution of this application will be further described in detail below with reference to specific embodiments. Please refer to... Figure 1 In the method for measuring the thickness of ultrathin film materials in this application, surface mass spectra are first acquired using a primary ion source on both the ultrathin film and the substrate surface to determine the characteristic ion peaks of the ultrathin film and the substrate. TOF-SIMS technology uses a focused primary ion beam to bombard the sample surface, exciting and collecting secondary ions generated by sputtering. The mass-to-charge ratio is determined based on their time-of-flight, thereby obtaining mass spectral information reflecting the surface chemical composition. Since different materials have characteristic mass spectral peaks, by comparing the mass spectra of the thin film region with those of the substrate region without film coverage, characteristic ion peaks representing the film material itself and the underlying substrate material can be selected respectively. This step establishes a clear and real-time monitorable identification basis for subsequent etching endpoint determination.

[0025] Subsequently, the first target etching micro-region was selected, and the ultrathin film was etched using a sputtering ion source. The etching and spectral acquisition processes were alternated until the characteristic ion peaks of the substrate appeared and their ion intensities remained stable, thus completing the preparation of one etched micro-region. This etching process was then repeated to form multiple spaced target etched micro-regions on the sample surface. In this step, the micro-regions were peeled off layer by layer using a sputtering ion source, which is a dynamic TOF-SIMS depth analysis mode. The mass spectrometry signal was monitored in real time during the etching process. When the characteristic ion peaks of the substrate appeared and tended to stabilize, it indicated that the ultrathin film layer covering the substrate within the micro-region had been completely removed. By controlling the operating parameters of the sputtering ion source and the size of the etched micro-regions, multiple etch pits with well-defined boundaries and relatively uniform morphology can be formed on the surface of the polymer ultrathin film.

[0026] Finally, the etched sample is removed from the TOF-SIMS sample chamber and placed under the optical lens of a profilometer to observe the multiple target etched micro-regions formed. The probe of the profilometer is controlled to move across the surface of the micro-region at a set speed and direction. The displacement change of the probe due to the topographic difference between the etched pit and the surrounding original film surface is recorded, thus obtaining the depth curve of the etched pit. The thickness values ​​of multiple consecutive micro-regions are read, and their average value is taken as the thickness of the etched micro-region, i.e., the film thickness of the polymer ultrathin film to be measured. As a contact surface profile measurement instrument, the profilometer can accurately measure the step height changes at the micrometer and even nanometer scale through probe scanning. Its measurement results are not limited by the specific sample material type, reflectivity, or hardness, and have wide applicability. This application reduces the random errors that may be introduced by a single measurement (such as those caused by probe positioning deviation, local microscopic defects on the sample surface, etc.) by measuring multiple independently prepared etched micro-regions and taking the average value, thereby obtaining more representative film thickness data.

[0027] Regarding the type of sputtering ion source, it can be selected from argon ion sources, argon cluster ion sources, C60, or cesium ion sources. Different types of ion sources exhibit different sputtering characteristics when interacting with materials due to their different physical properties. When using C60 or argon cluster ion beams to sputter organic materials, acceptable sputtering rates can be obtained while minimizing damage to the molecular structure of the polymer material, thus helping to maintain the smoothness of the film surface during etching. Those skilled in the art can select from the above-mentioned ion source types according to the specific composition of the polymer ultrathin film to be tested.

[0028] During etching, the operating voltage can be controlled within the range of 1 kV to 20 kV, the current can be controlled within the range of 0.1 nA to 20 nA, and the etching time can be adjusted within the range of 1 s to 30 s. When the sputtering ion source is working, the vacuum degree in the sample chamber can be controlled within the range of 1×10^-7 Pa to 5×10^-5 Pa, ensuring that the ion source can peel off the ultrathin film layer by layer without causing mechanical damage to the film layer around the micro-region, thereby obtaining a uniform etching morphology in each micro-region, providing a basis for the accurate measurement of the subsequent profilometer.

[0029] The side length of the etched micro-regions can be selected within the range of 10 μm to 500 μm, and the spacing between adjacent target etched micro-regions can also be selected within the range of 10 μm to 500 μm. Using an interleaved arrangement ensures that the micro-regions do not interfere with each other during measurement. Furthermore, the number of target etched micro-regions can be set to three or more. By measuring the thickness of multiple independent micro-regions and taking the average, the random errors that may be introduced by a single measurement can be effectively reduced, making the final film thickness data more representative.

[0030] Regarding the substrate type and film thickness range, the substrate can be selected from glass, ITO, silicon wafers, or mica. For the aforementioned substrate materials, existing research has provided characteristic spectral peak data in TOF-SIMS analysis, facilitating accurate identification of substrate signals during etching. The thickness of the ultrathin film can range from 1 nm to 200 nm. As a contact surface profile measurement instrument, the profilometer has no special requirements regarding the reflectivity characteristics, material type, or hardness of the sample being measured, and can adapt to the measurement needs of polymer films with different compositions within the aforementioned thickness range.

[0031] The probe movement direction can be set to be parallel to one edge of the etched micro-region, which helps the probe obtain a clear and complete step profile curve when crossing the boundary of the etch pit. The probe movement speed can be selected in the range of 20 μm / s to 100 μm / s. Based on the technical characteristics of the profilometer, at a reasonable scanning speed, combined with its sub-angstrom vertical resolution (up to 0.01 nm) and high repeatability (4 Å or 0.10%), the depth information of the etch pit can be accurately recorded.

[0032] The following will further introduce some specific implementation methods to provide a more detailed explanation of the technical solution of this application.

[0033] Example 1 In one specific embodiment, a polyimide ultrathin film on a glass substrate is used as an example, with a thickness of 75 nm. The sample coated with the polyimide ultrathin film is placed in the sample chamber of a TOF-SIMS system, and after vacuuming, transferred to the test chamber. The TOF-SIMS device used in this embodiment is the commercially available ULVAC PHI nanoTOF 3 model.

[0034] The steps for forming a uniform etched region on the surface of a polymer ultrathin film using TOF-SIMS depth analysis technology are as follows: Surface mass spectrometry was performed on the surfaces of polyimide ultrathin films and blank glass substrates using a TOF-SIMS bismuth ion source (primary ion source) to determine the characteristic ion peaks of the polyimide film and the glass substrate. When acquiring surface mass spectrometry, positive ion mode was selected, the sampling area was set to 400 μm, the number of acquisition frames was set to 10, and the mass range was set to 1-1850. Characteristic ion peaks for the polyimide film could be selected from C3H3, C5H5, C6H5, C7H7, C8H9, etc., while characteristic ion peaks for the underlying glass substrate could be selected from Si, In, Na, Al, K, etc. This step serves to establish a clear chemical identification basis for subsequent etching endpoint determination.

[0035] The first target etching micro-region was selected, with an etching area of ​​100 μm × 100 μm. An argon cluster ion source was used as the sputtering ion source, with an operating voltage of 10 kV and a current of 10 nA. The vacuum level in the sample chamber was 1 × 10⁻⁶ Pa. The polymer film was etched for 5 s, alternating between etching and spectral acquisition until the characteristic ion peaks of the substrate appeared and the ion intensity remained constant, thus completing the etching of micro-region 1. It should be noted that the type of sputtering ion source can be selected as needed. In addition to the argon cluster ion source used in this embodiment, other sources such as argon ion sources, C60, or cesium ion sources can also be selected. When using different types of ion sources, their operating parameters need to be adjusted accordingly. During etching, the operating voltage can be adjusted within the range of 1 kV to 20 kV, the current within the range of 0.1 nA to 20 nA, the etching time within the range of 1 s to 30 s, and the vacuum level in the sample chamber can be controlled within the range of 1 × 10⁻⁷ Pa to 5 × 10⁻⁵ Pa. The selection of the above parameters should ensure that the sputtering ion source does not cause damage to the periphery of the micro-region and that the morphology within each micro-region remains uniform.

[0036] Target micro-regions 2 are positioned 100 μm apart from the first target etched micro-region. The spacing between adjacent target etched micro-regions can be selected within the range of 10 μm to 500 μm. The precise position of the micro-regions is controlled by a displacement controller on the software. The selected micro-regions should be positioned away from the projected area of ​​the sputtered ions and should not intersect each other.

[0037] Repeat the etching process described above to form multiple target etched micro-regions. In this embodiment, three target etched micro-regions are formed. The number of target etched micro-regions can be set to more than three (e.g., four to ten) as needed to obtain more reliable measurement results. The side length of the etched micro-regions can be selected in the range of 10 μm to 500 μm.

[0038] The components of the polymer ultrafilm are not limited to polyimide, but can also be selected from various general-purpose polymer materials, including but not limited to polyethylene, polypropylene, polystyrene, polyvinyl chloride, polytetrafluoroethylene, polyester, polyether, polyetheretherketone, polysiloxane, etc. The substrate is not limited to glass, but can also be selected from ITO glass, silicon wafers, coated silicon wafers, mica, etc. The thickness of the ultrafilm can be in the range of 1 nm to 200 nm.

[0039] After etching is completed, the thickness of the etched micro-region is measured using a profilometer. The specific steps are as follows: The polyimide ultrathin film sample was removed from the TOF-SIMS sample chamber and placed under the optical lens of the profilometer to observe the multiple target etched micro-regions formed. The profilometer used in this embodiment was a commercially available KLA / P-7 model.

[0040] The probe of the profilometer is moved across the surface of the micro-area at a speed of 20 μm / s, with the direction of movement parallel to one edge of the etched micro-area. The probe's movement speed can be selected within the range of 20 μm / s to 100 μm / s. Setting the probe's movement direction to be parallel to one edge of the etched micro-area helps to obtain a clear and complete step profile curve when crossing the boundary of the etch pit.

[0041] Because of the topographic difference between the etched pit and the surrounding film, the probe can record the depth curve of the etched pit as it moves.

[0042] The thickness of multiple consecutive micro-regions is read. In this embodiment, the thicknesses of three consecutive micro-regions are read: 73.08 nm, 71.51 nm, and 72.66 nm. The average value of 72.42 nm is taken as the thickness of the etched micro-regions, i.e., the film thickness of the polymer ultrathin film. The number of micro-regions tested by the profilometer can be selected from 1 to 10.

[0043] To compare the accuracy of the above testing methods, polyimide films from the same batch were taken, and the film surface was scratched with a blade. The thickness of the film was then directly measured using a profilometer, and the thickness was found to be 73.01 nm. The results were basically consistent, indicating that the method of forming an etched area on the surface of the polymer ultrathin film using TOF-SIMS depth analysis technology and combining it with multi-point measurement using a profilometer can accurately obtain the thickness of the ultrathin film.

[0044] Example 2 In another specific embodiment, a polystyrene ultrathin film on a silicon wafer substrate is used as an example, with a thickness of 50 nm. The sample coated with the polystyrene ultrathin film is placed in the sample chamber of a TOF-SIMS device, and after vacuuming, transferred to the test chamber. The TOF-SIMS device used in this embodiment is the commercially available ULVAC PHI nanoTOF 3 model.

[0045] The steps for forming a uniform etched region on the surface of a polymer ultrathin film using TOF-SIMS depth analysis technology are as follows: Surface mass spectra are acquired using a bismuth ion source (primary ion source) of TOF-SIMS on both the polystyrene ultrathin film and a blank silicon substrate to determine the characteristic ion peaks of the polystyrene film and the silicon substrate. When acquiring surface mass spectra, positive ion mode is selected, the sampling area can be set to 400 μm, the number of acquisition frames is set to 10, and the mass range is set to 1-1850. The characteristic ion peaks of the polystyrene film can be selected from C4H3, C5H5, C7H7, etc., and the characteristic ion peaks of the underlying silicon substrate can be selected from Si, SiH, SiC, etc. The purpose of this step is to establish a clear chemical identification basis for subsequent etching endpoint determination.

[0046] The first target etching micro-region was selected, with an etching area of ​​100 μm × 100 μm. An argon cluster ion source was used as the sputtering ion source, with an operating voltage of 5 kV and a current of 5 nA. The vacuum level in the sample chamber was 1 × 10⁻⁶ Pa. The polymer film was etched for 8 s, alternating between etching and spectral acquisition until the characteristic ion peaks of the substrate appeared and the ion intensity remained constant, thus completing the etching of micro-region 1. It should be noted that the type of sputtering ion source can be selected as needed. In addition to the argon cluster ion source used in this embodiment, other sources such as argon ion sources, C60, or cesium ion sources can also be selected. When using different types of ion sources, their operating parameters need to be adjusted accordingly. During etching, the operating voltage can be adjusted from 1 kV to 20 kV, the current from 0.1 nA to 20 nA, the etching time from 1 s to 30 s, and the vacuum level in the sample chamber can be controlled within the range of 1 × 10⁻⁷ Pa to 5 × 10⁻⁵ Pa. The selection of the above parameters should ensure that the sputtering ion source does not cause damage to the periphery of the micro-region and that the morphology within each micro-region remains uniform.

[0047] Target micro-regions 2 are positioned 150 μm apart in the vicinity of the first target etched micro-region. The spacing between adjacent target etched micro-regions can be selected within the range of 10 μm to 500 μm. The precise position of the micro-regions is controlled by a displacement controller on the software. The selected micro-regions should be positioned away from the projected area of ​​the sputtered ions and should not intersect each other.

[0048] Repeat the etching process described above to form multiple target etched micro-regions. In this embodiment, four target etched micro-regions are formed. The number of target etched micro-regions can be set to more than three as needed to obtain more reliable measurement results. The side length of the etched micro-regions can be selected in the range of 10 μm to 500 μm.

[0049] The components of the polymer ultrafilm are not limited to polystyrene, but can also be selected from various general-purpose polymer materials, including but not limited to polyethylene, polypropylene, polyvinyl chloride, polytetrafluoroethylene, polyester, polyether, polyimide, polyetheretherketone, polysiloxane, etc. The substrate is not limited to silicon wafers, but can also be selected from glass, ITO glass, coated silicon wafers, mica, etc. The thickness of the ultrafilm can be in the range of 1 nm to 200 nm.

[0050] After etching is completed, the thickness of the etched micro-region is measured using a profilometer. The specific steps are as follows: The polystyrene ultrathin film sample was removed from the TOF-SIMS sample chamber and placed under the optical lens of the profilometer to observe the multiple target etched micro-regions formed. The profilometer used in this embodiment is a commercially available KLA / P-7 model.

[0051] The probe of the profilometer is moved across the surface of the micro-area at a speed of 50 μm / s, with the direction of movement parallel to one edge of the etched micro-area. The probe's movement speed can be selected within the range of 20 μm / s to 100 μm / s. Setting the probe's movement direction to be parallel to one edge of the etched micro-area helps to obtain a clear and complete step profile curve when crossing the boundary of the etch pit.

[0052] Because of the topographic difference between the etched pit and the surrounding film, the probe can record the depth curve of the etched pit as it moves.

[0053] The thickness of multiple consecutive micro-regions is read. In this embodiment, the thicknesses of four consecutive micro-regions are read: 49.28 nm, 50.15 nm, 48.97 nm, and 50.32 nm. The average value of 49.68 nm is taken as the thickness of the etched micro-regions, i.e., the film thickness of the polymer ultrathin film. The number of micro-regions tested by the profilometer can be selected from 1 to 10.

[0054] To compare the accuracy of the above testing methods, polystyrene films from the same batch were taken, and the film surface was scratched with a blade. The thickness of the film was then directly measured using a profilometer, and the thickness was found to be 50.12 nm. The results were basically consistent, indicating that the method of forming an etched area on the surface of the polymer ultrathin film using TOF-SIMS depth analysis technology and combining it with multi-point measurement using a profilometer can accurately obtain the thickness of the ultrathin film.

[0055] As described above, this application provides a method for measuring the thickness of ultrathin film materials. This method first utilizes TOF-SIMS technology to determine the characteristic ion peaks of the ultrathin film and the substrate in a single mass spectrometry acquisition using an ion source, which serves as the basis for determining the etching endpoint. Subsequently, a sputtering ion source is used to perform layer-by-layer etching on the film surface, and through alternating etching and spectral acquisition processes, multiple spaced, uniformly shaped target etched micro-regions are formed. Finally, the sample is transferred to a profilometer, and the probe is controlled to scan and record the depth curves of each etched micro-region. The thickness values ​​of multiple micro-regions are read and their average value is taken as the film thickness of the ultrathin film.

[0056] This application ensures the uniformity of the etched area by controlling the type of sputtering ion source (such as argon ion source, argon cluster ion source, C60 or cesium ion source) and its operating parameters (voltage 1-20 kV, current 0.1-20 nA, etching time 1-30 s, vacuum degree 1×10^-7~5×10^-5 Pa), as well as limiting the size (side length 10-500 μm) and spacing (10-500 μm) of the etched micro-areas, thus providing a good foundation for subsequent measurements. Simultaneously, by setting multiple (≥3) target micro-areas and performing multi-point measurements and averaging, combined with optimization of the probe movement direction (parallel to the edge of the micro-area) and speed (20-100 μm / s), the random errors that may be introduced by a single measurement are effectively reduced, improving the accuracy and repeatability of film thickness measurement. This method is applicable to various types of polymer ultrathin films with thicknesses ranging from 1 to 200 nm and substrates such as glass, ITO, silicon wafers, or mica. The results are consistent with those of other film thickness testing methods, demonstrating good applicability and reliability.

[0057] The above is only one specific implementation of this application, and any other improvements made based on the concept of this application shall be considered within the scope of protection of this application.

Claims

1. A method for measuring the thickness of an ultrathin film material, characterized in that, Includes the following steps: Surface mass spectra were collected on the ultrafilm and substrate surfaces using a primary ion source to determine the characteristic ion peaks of the ultrafilm and substrate. Select an etching micro-region, use a sputtering ion source to etch the ultrathin film, and alternate the etching and spectral sampling processes until the characteristic ion peaks of the substrate appear and the ion intensity remains unchanged, thus completing the etching micro-region. Repeat the etching micro-region process to form multiple target etched micro-regions arranged at intervals. The sample is placed in a profilometer, and the probe is controlled to move on the surface of the micro-region. As the probe moves, the depth curve of the etched pit is recorded, and the thickness of multiple target etched micro-regions is read. The average value is taken as the thickness of the etched micro-region, and the film thickness of the polymer ultrathin film is obtained.

2. The method for measuring the thickness of ultrathin film materials according to claim 1, characterized in that, The sputtering ion source is an argon ion source, an argon cluster ion source, a C60 ion source, or a cesium ion source.

3. The method for measuring the thickness of ultrathin film materials according to claim 1, characterized in that, The etching operation voltage is in the range of 1kV-20kV, the current is in the range of 0.1nA-20nA, and the etching time is in the range of 1s-30s.

4. The method for measuring the thickness of ultrathin film materials according to claim 1, characterized in that, The side length of the etched micro-region is in the range of 10 μm to 500 μm.

5. The method for measuring the thickness of ultrathin film materials according to claim 4, characterized in that, The spacing between adjacent etched micro-regions is in the range of 10 μm to 500 μm.

6. The method for measuring the thickness of ultrathin film materials according to claim 4, characterized in that, The number of target etched micro-regions is greater than or equal to 3.

7. The method for measuring the thickness of ultrathin film materials according to claim 1, characterized in that, The substrate is glass, ITO, silicon wafer, or mica.

8. The method for measuring the thickness of ultrathin film materials according to claim 1, characterized in that, The thickness of the ultrathin film is in the range of 1 nm to 200 nm.

9. The method for measuring the thickness of ultrathin film materials according to claim 1, characterized in that, The probe moves in a direction parallel to one edge of the etched micro-region.

10. The method for measuring the thickness of ultrathin film materials according to claim 1, characterized in that, The probe's movement speed is in the range of 20 μm / s to 100 μm / s.

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