Film thickness detection method of liquid crystal alignment film
Through the combination of ToF-SIMS technology and argon cluster ion source, the problem of film thickness measurement in the Halo region of TFT-LCD liquid crystal alignment film is solved, and the film thickness information is obtained continuously, and the film thickness uniformity information is provided, and the measurement accuracy and repeatability are improved.
Patent Information
- Application Number
- CN202510067364.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-16
- Publication Date
- 2025-04-22
AI Technical Summary
The prior art is difficult to continuously obtain accurate film thickness information in the Halo region of the TFT-LCD liquid crystal alignment film, especially in the case where complex metal lines and functional coatings exist in the panel frame area.
Time-of-flight secondary ion mass spectrometry (ToF-SIMS) technology was used to determine the characteristic ion peaks of the liquid crystal alignment film and substrate through surface mass spectrometry analysis, and alternating etching and spectrum were used to obtain film thickness information.
It realizes continuous acquisition of the film thickness information of the liquid crystal alignment film over a large range, provides accurate film thickness uniformity information, solves the problems of low measurement accuracy and dependence on operation experience in the prior art, and has good repeatability of the test results.
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Figure CN119860705A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of display technology, and in particular to a method for detecting the film thickness of a liquid crystal alignment film. Background Art
[0002] In TFT-LCD technology, the liquid crystal alignment film controls the pre-tilt angle of liquid crystal molecules and is a key material that determines the display performance of the panel. The commonly used liquid crystal alignment film is polyimide (PI) material. The film formation process is as follows: the polyamic acid stock solution is formed on a conductive glass substrate through different coating methods (spin coating method, inkjet printing method, etc.), heated and cured to form polyimide, and then rubbed or photo-aligned to form a liquid crystal alignment film with alignment ability.
[0003] Among various coating and film-forming methods, inkjet printing technology can precisely control the volume and position of PI droplets, is easy to pattern, has high material utilization, has the advantages of high production capacity, fast product switching, and material saving, and has become the mainstream technology for high-generation lines. However, during the natural leveling and film-forming process of droplets, due to the low viscosity of the PI stock solution, it is difficult to control the PI film thickness and morphology in the display edge area, and uneven film thickness is prone to occur. The uneven area formed by the diffusion of PI at the edge of the substrate is also called the Halo area, which is generally manifested as a "peak" of PI at the edge, and the PI film thickness between the inward and normal display areas is thin.
[0004] In recent years, with the demand for narrow-border and borderless products in panel displays, the distance from the PI edge to the display area has been continuously compressed, making it more likely to have uneven peripheral PI coating problems. The resulting poor display has seriously restricted the development of narrow-border technology.
[0005] In order to control the film-forming process of the peripheral PI, it is necessary to obtain the morphological information of the liquid crystal alignment film in the Halo area, accurately measure the film thickness of the PI film in this area, and compare it with the film thickness in the normal display area. The most commonly used film thickness measurement method is the step meter method based on probe contact. For example, different points are selected on the film surface to measure the film thickness using a step meter, and its accuracy depends on the displacement and the sharpness of the probe tip. In addition, the morphology of the alignment film on the cross-section of the Halo area can be directly observed through an electron microscope to measure the film thickness of the PI.
[0006] However, the above test methods all have limitations. On the one hand, the step meter can only provide film thickness information at a single point or in a very small range, the preparation method of electron microscopy is cumbersome, and the film thickness measurement is extremely dependent on the operator's experience; on the other hand, there are more complex metal circuits and functional coatings in the panel frame area, and the frame terrain will affect the step meter scribing and microscopy. Therefore, in order to solve the problem of film thickness measurement of TFT-LCD liquid crystal alignment film, it is urgent to develop a new method to continuously obtain the film thickness information of the PI film layer in a larger range. Summary of the invention
[0007] Purpose of the invention: To provide a method for detecting the film thickness of a liquid crystal alignment film, so as to at least solve one of the problems existing in the above-mentioned prior art.
[0008] Technical solution: A method for detecting the film thickness of a liquid crystal alignment film, comprising: ToF-SIMS was used to collect the surface mass spectrum at the edge of the liquid crystal alignment film on the substrate; Determining characteristic ion peaks of the liquid crystal alignment film and the substrate respectively according to the surface mass spectrum; The outer edge position of the liquid crystal alignment film is used as a first etching micro-region, and the first etching micro-region is alternately etched and spectrum collected according to a preset etching process to obtain a first depth curve; The etching time of the first etching micro-region is read based on the first depth curve, and the etching time is associated with the film thickness of the liquid crystal alignment film to obtain film thickness information.
[0009] Preferably, before collecting the surface mass spectrum of the edge position of the liquid crystal alignment film on the substrate by ToF-SIMS, the method further comprises: Take the panel coated with PI alignment film, cut samples around the display area of the panel, put the cut samples into the ToF-SIMS sample chamber, and transfer them to the test chamber after vacuuming; Wherein, the length and width of the sample do not exceed 1.5 cm.
[0010] Preferably, using ToF-SIMS to collect a surface mass spectrum at an edge position of a liquid crystal alignment film on a substrate comprises: When collecting the surface mass spectrum at the edge of the liquid crystal alignment film, select the positive ion or negative ion mode, set the spectrum collection area to 20-200 μm, set the collection frame number to 5-20 times, and the mass range to 1-1850.
[0011] Preferably, determining characteristic ion peaks of the liquid crystal alignment film and the substrate respectively according to the surface mass spectrum comprises: When the positive ion mode is selected, the characteristic ion peak of the liquid crystal alignment film is C2H3, C3H5, C4H9, C6H5, C7H7 or C8H9, and the characteristic ion peak of the substrate is Si, In, Na, Al or K; When the negative ion mode is selected, the characteristic ion peak of the liquid crystal alignment film is CN, CNO, CH3N or C6H, and the characteristic ion peak of the substrate is SiO, InO, NaOH, AlOH or KOH.
[0012] Preferably, the outer edge position of the liquid crystal alignment film is used as the first etching micro-region, and the first etching micro-region is alternately etched and spectrum collected according to a preset etching process to obtain a first depth curve, including: The outer edge position of the liquid crystal alignment film is used as a first etching micro-region, and the first etching micro-region is alternately etched and spectrum collected according to a preset etching time, etching area and a preset sputtering ion source to obtain a first depth curve; Wherein, the preset sputtering ion source is an argon cluster ion source.
[0013] Preferably, the first etched micro-region is alternately etched and sampled according to a preset etching time, etching area and a preset sputtering ion source to obtain a first depth curve, including: During etching, the working voltage of the argon cluster ion source is 1-20 kV, and the current is 0.1-20 nA; the area of the first etching micro-region is 50-200 μm, the etching time of the argon cluster ion source is 1-10 s, and the number of etchings is 5-100 times.
[0014] Preferably, after taking the outer edge position of the liquid crystal alignment film as the first etching micro-region, and performing alternating etching and spectrum sampling on the first etching micro-region according to a preset etching process to obtain a first depth curve; and before reading the etching time of the first etching micro-region based on the first depth curve, and correlating the etching time with the film thickness of the liquid crystal alignment film to obtain film thickness information, the method further includes: A plurality of second etched micro-regions are provided, wherein the plurality of second etched micro-regions are based on the first etched micro-region and are continuously extended from the outer edge of the first etched micro-region to the normal display area of the liquid crystal alignment film.
[0015] Preferably, the plurality of second etched micro-regions are based on the first etched micro-region and are continuously extended from the outer edge of the first etched micro-region to the normal display area of the liquid crystal alignment film, and further include: Alternately etching and sampling the spectrum of a plurality of the second etched micro-regions to obtain a plurality of second depth curves; The etching time of the corresponding second etching micro-regions is read based on the second depth curves, and the etching time is associated with the film thickness of the liquid crystal alignment film to obtain film thickness information.
[0016] Preferably, after reading the etching time of the corresponding second etching micro-regions based on the second depth curves and correlating the etching time with the film thickness of the liquid crystal alignment film to obtain the film thickness information, the method further comprises: The film thickness information is compared with the film thickness of the normal display area to obtain the film thickness uniformity information of the liquid crystal alignment film from the outer edge position to its normal display area.
[0017] Preferably, the number of the plurality of second etched micro-regions is 5-40.
[0018] Beneficial effect: In the embodiment of the present application, a method of measuring the thickness of the liquid crystal alignment film by time-of-flight secondary ion mass spectrometry (ToF-SIMS) is adopted, and the surface mass spectrum of the edge position of the liquid crystal alignment film on the substrate is collected by ToF-SIMS; the characteristic ion peaks of the liquid crystal alignment film and the substrate are determined respectively according to the surface mass spectrum; the outer edge position of the liquid crystal alignment film is used as the first etching micro-region, and the first etching micro-region is alternately etched and sampled according to a preset etching process to obtain a first depth curve; the etching time of the first etching micro-region is read based on the first depth curve, and the etching time is associated with the film thickness of the liquid crystal alignment film to obtain the film thickness information, thereby achieving the direct correlation between the etching time of the liquid crystal alignment film and the film thickness. The purpose of association is achieved, and the effect of being able to continuously obtain the film thickness of the liquid crystal alignment film in multiple etched micro-areas within a preset range is achieved, thereby providing accurate information for comparing the film thickness difference between the periphery of the display panel and the normal area, and the test results have good repeatability, and can be widely used in the technical effect of morphology characterization of PI alignment films in the periphery of panels with certain surface patterns, thereby solving the problem that the existing step meter can only provide film thickness information at a single point or in a very small range, the preparation method of electron microscopic sections is cumbersome, and the film thickness measurement is extremely dependent on the operator's experience; on the other hand, there are more complex metal circuits and functional coatings in the panel border area, and the border terrain will affect the step meter scribing and microscopic sectioning. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 It is a schematic flow chart of a method for detecting the film thickness of a liquid crystal alignment film of the present invention; Figure 2 It is a schematic flow chart of another method for detecting the film thickness of a liquid crystal alignment film of the present invention; Figure 3 A depth analysis curve of specific ions on a substrate measured by ToF-SIMS of the film thickness detection method of the liquid crystal alignment film of the present invention; and Figure 4The ToF-SIMS, which is a method for detecting the film thickness of the liquid crystal alignment film of the present invention, measures the etching time of the PI alignment film from the edge to the display center on the panel. DETAILED DESCRIPTION
[0020] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.
[0021] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.
[0022] In addition, the terms "installed", "set", "provided with", "connected", "connected", and "socketed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0023] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.
[0024] According to an embodiment of the present invention, a method for detecting the film thickness of a liquid crystal alignment film is provided. Figure 1-2 As shown, the method includes the following steps S101 to S104: Step S101, using ToF-SIMS to collect a surface mass spectrum of the edge of the liquid crystal alignment film on the substrate; By using time-of-flight secondary ion mass spectrometry (ToF-SIMS), it is possible to collect surface mass spectra of the edge of the liquid crystal alignment film on the substrate, thereby providing a basis and guarantee for subsequent accurate judgment. In the present application, the liquid crystal alignment film can be a PI film layer.
[0025] It is important to know that the working principle of ToF-SIMS for measuring film thickness is: ToF-SIMS is a powerful analytical technique for studying solid surfaces, which can provide mass spectra of organic material surfaces, observe the spatial distribution of surface ions, and the depth distribution of film layers. This technique uses a focused primary ion beam to bombard the sample surface, collects secondary ions ejected by sputtering, measures the mass of secondary ions by measuring their flight time, identifies secondary ions, and thus determines the chemical composition of the surface.
[0026] According to an embodiment of the present invention, preferably, using ToF-SIMS to collect a surface mass spectrum of an edge position of a liquid crystal alignment film on a substrate includes: When collecting the surface mass spectrum at the edge of the liquid crystal alignment film, select the positive ion or negative ion mode, set the spectrum collection area to 20-200 μm, set the collection frame number to 5-20 times, and the mass range to 1-1850.
[0027] Good data acquisition effects can be achieved, so that the signal changes between the PI film layer and the substrate can be determined, the characteristic ion peaks of the PI film layer can be located, and a reference can be provided for subsequent deep etching.
[0028] Step S102, determining characteristic ion peaks of the liquid crystal alignment film and the substrate respectively according to the surface mass spectrum; By analyzing the collected surface mass spectrum, the characteristic ion peaks of the PI film layer and the underlying substrate can be accurately determined.
[0029] According to an embodiment of the present invention, preferably, determining the characteristic ion peaks of the liquid crystal alignment film and the substrate respectively according to the surface mass spectrum includes: When the positive ion mode is selected, the characteristic ion peak of the liquid crystal alignment film is C2H3, C3H5, C4H9, C6H5, C7H7 or C8H9, and the characteristic ion peak of the substrate is Si, In, Na, Al or K; When the negative ion mode is selected, the characteristic ion peak of the liquid crystal alignment film is CN, CNO, CH3N or C6H, and the characteristic ion peak of the substrate is SiO, InO, NaOH, AlOH or KOH.
[0030] Specifically, the positive and negative ion modes are selected: data are collected in the positive ion mode (collecting characteristic ion peaks of the PI film layer and the substrate, such as C3H3⁺, C5H5⁺, etc.) and the negative ion mode (collecting characteristic ion peaks, such as CN⁻, CNO⁻, etc.); Collection area: 100μm sampling area to ensure representative signals; Number of acquisition frames: Each data point was acquired 10 times to reduce noise and improve the signal-to-noise ratio of the data; The mass range was 1–1850 m / z, ensuring that all relevant ion peaks were covered.
[0031] By collecting mass spectrometry data in positive and negative ion modes, the characteristic ion peaks of the PI film layer and substrate can be accurately identified, thereby determining the thickness of the film layer.
[0032] Step S103, taking the outer edge position of the liquid crystal alignment film as a first etching micro-region, and performing alternating etching and spectrum acquisition on the first etching micro-region according to a preset etching process to obtain a first depth curve; By taking the outermost edge of the liquid crystal alignment film as the first etching micro-region and performing alternate etching and spectrum sampling on the first etching micro-region according to a preset etching process, a first depth curve can be obtained, thereby providing a basis for obtaining the film thickness of the first etching micro-region.
[0033] According to an embodiment of the present invention, preferably, the outer edge position of the liquid crystal alignment film is used as a first etching micro-region, and the first etching micro-region is alternately etched and spectrum collected according to a preset etching process to obtain a first depth curve, including: The outer edge position of the liquid crystal alignment film is used as a first etching micro-region, and the first etching micro-region is alternately etched and spectrum collected according to a preset etching time, etching area and a preset sputtering ion source to obtain a first depth curve; Wherein, the preset sputtering ion source is an argon cluster ion source.
[0034] Specifically, TOF-SIMS can perform in-depth analysis of organic film layers. It uses another ion source to etch the film layer in the intervals between spectrum sampling, alternating spectrum sampling and etching processes to obtain thickness information of the film layer. In order to reduce the damage caused by the ion beam to the organic molecular structure during the etching process, an argon cluster ion source (GCIB) is usually used to perform in-depth analysis of organic materials to achieve relatively "gentle" etching.
[0035] For a specific film layer, it is generally believed that the etching rate is constant, so the film thickness is proportional to the time (t) required to etch the entire film layer. The longer the etching time t, the thicker the film layer.
[0036] It is important to know that the Gas Cluster Ions Beam (GCIB) is a technology that uses argon gas clusters (a group of multiple argon atoms) as ion sources to produce argon cluster ion beams. It is an important technology in the fields of material surface treatment, thin film deposition, and surface analysis. Compared with traditional single ion beams, argon cluster ions have larger mass and lower kinetic energy, which gives it unique advantages in a variety of applications, especially in reducing surface damage and improving processing quality and accuracy.
[0037] The basic principle of argon cluster ion source: Cluster generation: By injecting argon gas and allowing argon molecules to aggregate under specific conditions (such as high electric field or low temperature environment), clusters consisting of tens to thousands of argon atoms are formed. The size of the argon cluster depends on the design of the source and the experimental requirements.
[0038] Acceleration and ionization: Argon clusters in the argon cluster ion source are accelerated to high speeds and turned into ions after being accelerated by an electric field. Compared with traditional monatomic ions, cluster ions have a larger mass, which enables them to have higher mass and energy transfer capabilities while maintaining lower energy damage.
[0039] Ion beam output: A cluster ion beam is directed toward a target surface, typically using a focusing system to precisely control the energy, direction, and size of the ion beam.
[0040] According to an embodiment of the present invention, preferably, the first etched micro-region is alternately etched and sampled according to a preset etching time, etching area and a preset sputtering ion source to obtain a first depth curve, including: During etching, the working voltage of the argon cluster ion source is 1-20 kV, and the current is 0.1-20 nA; the area of the first etching micro-region is 50-200 μm, the etching time of the argon cluster ion source is 1-10 s, and the number of etchings is 5-100 times.
[0041] By adopting the above etching process parameters, a good etching effect can be achieved, thereby obtaining accurate data information.
[0042] According to an embodiment of the present invention, preferably, after taking the outer edge position of the liquid crystal alignment film as the first etching micro-region, and performing alternating etching and spectrum sampling on the first etching micro-region according to a preset etching process to obtain a first depth curve; and before reading the etching time of the first etching micro-region based on the first depth curve, and correlating the etching time with the film thickness of the liquid crystal alignment film to obtain film thickness information, the method further includes: Step S105 , forming a plurality of second etched micro-regions, wherein the plurality of second etched micro-regions are based on the first etched micro-region and are continuously extended from the outer edge of the first etched micro-region to the normal display area of the liquid crystal alignment film.
[0043] By continuously extending a plurality of second etching micro-regions from the outer edge of the first etching micro-region to the normal display area of the liquid crystal alignment film, it is possible to provide a guarantee for etching the plurality of micro-regions later.
[0044] According to an embodiment of the present invention, preferably, the plurality of second etched micro-regions are based on the first etched micro-region and are continuously extended from the outer edge position of the first etched micro-region to the normal display area of the liquid crystal alignment film, and further include: Step S106, performing alternating etching and spectrum acquisition on a plurality of the second etched micro-areas to obtain a plurality of second depth curves; Step S107, based on the first depth curve and the plurality of second depth curves, read the etching time of the corresponding first etching micro-area and the plurality of second etching micro-areas, associate the etching time with the film thickness of the liquid crystal alignment film and compare them to obtain the film thickness and uniformity information of the liquid crystal alignment film from the outer edge position to its normal display area.
[0045] Specifically, the etching time of the corresponding first etching micro-region and the plurality of the second etching micro-regions is read based on the first depth curve and the plurality of the second depth curves, and the etching time is associated with the film thickness of the liquid crystal alignment film to obtain film thickness information.
[0046] It can accurately obtain the film thickness information of multiple etched micro-areas along the preset direction, thereby providing a data basis for subsequent film thickness detection and judgment.
[0047] like Figure 4 As shown, after reading the etching time of the corresponding first etching micro-region and the plurality of the second etching micro-regions based on the first depth curve and the plurality of the second depth curves, and correlating the etching time with the film thickness of the liquid crystal alignment film to obtain the film thickness information, the method further includes: The film thickness information is compared with the film thickness of the normal display area to obtain the film thickness uniformity information of the liquid crystal alignment film from the outer edge position to its normal display area.
[0048] Specifically, multiple micro-areas are continuously selected from the edge of the PI alignment film to the normal display area for depth analysis. The position of the micro-area is controlled by a displacement controller on the software. The etching time of the PI film layer in each micro-area is read from the depth curve. Since the thickness of the PI film layer is proportional to the etching time, the etching time of the PI film layer in each micro-area is compared to obtain the thickness distribution information of the PI film layer in a larger range from the Halo area to the normal display area.
[0049] like Figure 3 As shown, the signal intensity of specific ions on the PI alignment film and the substrate are recorded respectively, and the corresponding depth analysis curve is drawn. The time corresponding to the 50% change in the ion signal intensity is defined as the etching time t; in the edge area of the display panel, multiple etching areas are selected for depth analysis experiments in turn, and the etching time of the PI film layer in each area is compared to obtain the film thickness and distribution information of the PI film layer in the Halo area.
[0050] According to an embodiment of the present invention, preferably, the number of the plurality of second etched micro-regions is 5-40.
[0051] By setting a plurality of second etching micro-areas, the effect of improving data accuracy can be achieved, thereby providing a guarantee for obtaining more accurate data information.
[0052] Step S104 , reading the etching time of the first etching micro-region based on the first depth curve, and correlating the etching time with the film thickness of the liquid crystal alignment film to obtain film thickness information.
[0053] By associating the etching time with the film thickness of the liquid crystal alignment film, the corresponding film thickness information can be obtained, thereby achieving a good film thickness detection effect.
[0054] From the above description, it can be seen that the present application achieves the following technical effects: In an embodiment of the present application, a time-of-flight secondary ion mass spectrometry (ToF-SIMS) method is used to determine the thickness of the liquid crystal alignment film. The surface mass spectrum of the edge position of the liquid crystal alignment film on the substrate is collected by ToF-SIMS; the characteristic ion peaks of the liquid crystal alignment film and the substrate are determined respectively according to the surface mass spectrum; the outer edge position of the liquid crystal alignment film is used as the first etching micro-region, and the first etching micro-region is alternately etched and sampled according to a preset etching process to obtain a first depth curve; the etching time of the first etching micro-region is read based on the first depth curve, and the etching time is associated with the film thickness of the liquid crystal alignment film to obtain the film thickness information, thereby achieving the direct association of the etching time of the liquid crystal alignment film with the film thickness. The purpose is to achieve the effect of being able to continuously obtain the film thickness of the liquid crystal alignment film in multiple etched micro-areas within a preset range, thereby providing accurate information for comparing the film thickness difference between the periphery of the display panel and the normal area, and the test results have good repeatability, and can be widely used in the technical effect of morphology characterization of PI alignment films around panels with certain surface patterns, thereby solving the problems that the existing step meter can only provide film thickness information at a single point or in a very small range, the preparation method of electron microscopic sections is cumbersome, and the film thickness measurement is extremely dependent on the operator's experience; on the other hand, there are more complex metal circuits and functional coatings in the panel border area, and the border terrain will affect the step meter scribing and microscopic sections.
[0055] According to an embodiment of the present invention, preferably, before collecting the surface mass spectrum of the edge position of the liquid crystal alignment film on the substrate by ToF-SIMS, the method further includes: Take the panel coated with PI alignment film, cut samples around the display area of the panel, put the cut samples into the ToF-SIMS sample chamber, and transfer them to the test chamber after vacuuming; Wherein, the length and width of the sample do not exceed 1.5 cm.
[0056] Specifically, a substrate coated with a liquid crystal alignment film (such as a polyimide film) is selected. In order to perform ToF-SIMS surface analysis, a sample no longer than 1.5 cm in length and width is cut from the substrate to fit the analysis range of ToF-SIMS while ensuring that the edge of the film layer (Halo area) can be located.
[0057] Place the cut sample into the sample chamber of ToF-SIMS; to avoid contamination and background interference, the sample needs to be operated in a high vacuum environment.
[0058] The specific examples are further described below: 1. Collecting surface mass spectra Example 1 Take a panel coated with a PI alignment film, cut samples around the display of the panel, and the length and width of the samples should not exceed 1.5 cm; put the samples into the sample chamber of the ToF-SIMS, and transfer them to the test chamber after vacuuming.
[0059] On the ToF-SIMS operating software, locate the Halo area on the display periphery, collect the surface mass spectrum at the edge of the area, and determine the characteristic ion peaks of the PI film layer and the underlying substrate from the surface mass spectrum.
[0060] When collecting surface mass spectra, the positive ion mode was selected, the spectral area was 100 μm, the acquisition frame number was set to 10 times, and the mass range was 1-1850.
[0061] The characteristic ion peaks of the PI film layer can be C3H3, C5H5, C6H5, C7H7 or C8H9, etc.; the characteristic ion peaks of the lower substrate can be Si, In, Na, Al or K, etc.
[0062] Embodiment 2 Take a panel coated with a PI alignment film, cut samples around the display of the panel, and the length and width of the samples should not exceed 1.5 cm; put the samples into the sample chamber of the ToF-SIMS, and transfer them to the test chamber after vacuuming.
[0063] On the ToF-SIMS operating software, locate the Halo area on the display periphery, collect the surface mass spectrum at the edge of the area, and determine the characteristic ion peaks of the PI film layer and the underlying substrate from the surface mass spectrum.
[0064] When collecting surface mass spectra, the negative ion mode was selected, the spectral area was 100 μm, the acquisition frame number was set to 10 times, and the mass range was 1-1850.
[0065] The characteristic ion peaks of the PI film layer can be CN, CNO, CH3N or C6H, etc.; the characteristic ion peaks of the lower substrate can be SiO, InO, NaOH, AlOH or KOH, etc.
[0066] 2. In-depth analysis of PI alignment film layer Embodiment 3 The PI film layer was etched using an argon cluster ion source as a sputtering ion source, and the surface mass spectrum was collected between two etchings. The depth curve was obtained by alternating the etching and spectrum collection process. The etching time of the PI film layer was read from the depth curve.
[0067] During etching, the operating voltage of the GCIB ion source is 1-20 kV, and the current is 0.1-20 nA; when collecting spectra, the positive ion mode is selected, the collection area is 100 μm, the number of acquisition frames is set to 10 times, and the mass range is 1-1850; the outermost edge of the Halo area is taken as the first etching micro-area, the area of the etching micro-area is 50-200 μm, the etching time of the GCIB source is 1-10 s, and the number of GCIB etchings is 5-100 times.
[0068] On the depth curve, the characteristic ion peaks of the PI film layer can be C3H3, C5H5, C6H5, C7H7 or C8H9, etc., and the characteristic ion peaks of the underlying substrate can be Si, In, Na, Al or K, etc.
[0069] Further, multiple micro-areas are continuously selected from the edge to the normal display area for depth analysis, and the number of micro-areas is 5-40; From the depth curve, the etching time of the PI film layer in each micro-area is read; from the Halo area to the normal display area, the etching time of the PI film layer first increases, then decreases, and finally tends to be stable.
[0070] Embodiment 4 The PI film layer was etched using an argon cluster ion source as a sputtering ion source. The surface mass spectrum was collected between two etchings. The etching and spectrum collection processes were alternated to obtain a depth curve. The etching time of the PI film layer was read from the depth curve.
[0071] During etching, the operating voltage of the GCIB ion source is 1-20 kV, and the current is 0.1-20 nA; when collecting spectra, the negative ion mode is selected, the collection area is 100 μm, the number of acquisition frames is set to 10 times, and the mass range is 1-1850; the outermost edge of the Halo area is taken as the first etching micro-area, the area of the etching micro-area is 50-200 μm, and the etching time of the GCIB source is 1-10 s; the number of GCIB etchings is 5-100 times.
[0072] On the depth curve, the characteristic ion peak of the PI film layer can be CN, CNO, CH3N or C6H, etc.; the characteristic ion peak of the underlying substrate can be SiO, InO, NaOH, AlOH or KOH, etc.
[0073] Furthermore, multiple micro-areas are continuously selected from the edge to the normal display area for depth analysis, and the number of the micro-areas is 5-40.
[0074] From the depth curve, the etching time of the PI film layer in each micro-area is read; from the Halo area to the normal display area, the etching time of the PI film layer first increases, then decreases, and finally tends to be stable.
[0075] This application also has the following beneficial effects: The method of the present invention utilizes ToF-SIMS depth analysis to measure the film thickness of the PI alignment film, directly relates the etching time of the PI film layer to the film thickness, and can continuously obtain the PI film thickness of multiple etched micro-areas within a larger size range, providing accurate information for comparing the difference in film thickness between the periphery of the display panel and the normal area. The test results have good repeatability and do not need to rely on the operator's experience. It can be widely used in the morphology characterization of PI alignment films around panels with certain surface patterns.
[0076] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various equivalent transformations can be made to the technical scheme of the present invention, and these equivalent transformations all belong to the protection scope of the present invention.
Claims
1. A method for detecting the thickness of a liquid crystal alignment film, characterized in that: include: ToF-SIMS was used to collect the surface mass spectrum at the edge of the liquid crystal alignment film on the substrate; Determining characteristic ion peaks of the liquid crystal alignment film and the substrate respectively according to the surface mass spectrum; The outer edge position of the liquid crystal alignment film is used as a first etching micro-region, and the first etching micro-region is alternately etched and spectrum collected according to a preset etching process to obtain a first depth curve; The etching time of the first etching micro-region is read based on the first depth curve, and the etching time is associated with the film thickness of the liquid crystal alignment film to obtain film thickness information.
2. The method for detecting the film thickness of a liquid crystal alignment film according to claim 1, characterized in that: Before using ToF-SIMS to collect the surface mass spectrum of the edge position of the liquid crystal alignment film on the substrate, it also includes: Take the panel coated with PI alignment film, cut samples around the display area of the panel, put the cut samples into the ToF-SIMS sample chamber, and transfer them to the test chamber after vacuuming; Wherein, the length and width of the sample do not exceed 1.5 cm.
3. The method for detecting the film thickness of a liquid crystal alignment film according to claim 1, characterized in that: ToF-SIMS is used to collect the surface mass spectrum of the edge of the liquid crystal alignment film on the substrate, including: When collecting the surface mass spectrum at the edge of the liquid crystal alignment film, select the positive ion or negative ion mode, set the spectrum collection area to 20-200 μm, set the collection frame number to 5-20 times, and the mass range to 1-1850.
4. The method for detecting the film thickness of a liquid crystal alignment film according to claim 3, characterized in that: Determining characteristic ion peaks of the liquid crystal alignment film and the substrate respectively according to the surface mass spectrum includes: When the positive ion mode is selected, the characteristic ion peak of the liquid crystal alignment film is C2H3, C3H5, C4H9, C6H5, C7H7 or C8H9, and the characteristic ion peak of the substrate is Si, In, Na, Al or K; When the negative ion mode is selected, the characteristic ion peak of the liquid crystal alignment film is CN, CNO, CH3N or C6H, and the characteristic ion peak of the substrate is SiO, InO, NaOH, AlOH or KOH.
5. The method for detecting the film thickness of a liquid crystal alignment film according to claim 1, characterized in that: The outer edge position of the liquid crystal alignment film is used as a first etching micro-region, and the first etching micro-region is alternately etched and spectrum collected according to a preset etching process to obtain a first depth curve, including: The outer edge position of the liquid crystal alignment film is used as a first etching micro-region, and the first etching micro-region is alternately etched and spectrum collected according to a preset etching time, etching area and a preset sputtering ion source to obtain a first depth curve; Wherein, the preset sputtering ion source is an argon cluster ion source.
6. The method for detecting the film thickness of a liquid crystal alignment film according to claim 5, characterized in that: Alternately etching and sampling the first etching micro-region according to a preset etching time, etching area and a preset sputtering ion source to obtain a first depth curve, including: During etching, the working voltage of the argon cluster ion source is 1-20 kV, and the current is 0.1-20 nA; the area of the first etching micro-region is 50-200 μm, the etching time of the argon cluster ion source is 1-10 s, and the number of etchings is 5-100 times.
7. The method for detecting the film thickness of a liquid crystal alignment film according to claim 1, characterized in that: The outer edge position of the liquid crystal alignment film is used as a first etching micro-region, and the first etching micro-region is alternately etched and spectrum collected according to a preset etching process to obtain a first depth curve; Before reading the etching time of the first etching micro-region based on the first depth curve and correlating the etching time with the film thickness of the liquid crystal alignment film to obtain film thickness information, the method further includes: A plurality of second etched micro-regions are provided, wherein the plurality of second etched micro-regions are based on the first etched micro-region and are continuously extended from the outer edge of the first etched micro-region to the normal display area of the liquid crystal alignment film.
8. The method for detecting the film thickness of a liquid crystal alignment film according to claim 7, characterized in that: A plurality of second etched micro-regions, wherein the plurality of second etched micro-regions are based on the first etched micro-region and are continuously extended from the outer edge position of the first etched micro-region to the normal display area of the liquid crystal alignment film, and further comprising: Alternately etching and sampling the spectrum of a plurality of the second etched micro-regions to obtain a plurality of second depth curves; The etching time of the corresponding second etching micro-regions is read based on the second depth curves, and the etching time is associated with the film thickness of the liquid crystal alignment film to obtain film thickness information.
9. The method for detecting the film thickness of a liquid crystal alignment film according to claim 8, characterized in that: After reading the etching time of the corresponding second etching micro-regions based on the second depth curves and correlating the etching time with the film thickness of the liquid crystal alignment film to obtain film thickness information, the method further includes: The film thickness information is compared with the film thickness of the normal display area to obtain the film thickness uniformity information of the liquid crystal alignment film from the outer edge position to its normal display area.
10. The method for detecting the film thickness of a liquid crystal alignment film according to claim 7, characterized in that: The number of the plurality of second etched micro-regions is 5-40.