A method for measuring the etching rate of a thin film layer

Abstract

The application discloses a kind of film layer etching rate determination method, specifically includes the following steps: (1) on the support layer substrate of known composition, adhere one or more coating to form a film;(2) accurately obtain the thickness value and characteristic element of each coating;(3) obtain the composition and chemical state information of the most surface layer element;(4) clean etching to film;(5) record etching time, etching area, etching mode and etching energy;(6) establish the function relationship of X-ray photoelectron spectrometer argon ion sputtering source to the etching rate of corresponding coating of film.The application mainly utilizes argon ion beam to bombard the surface of film layer, then through X-ray photoelectron spectrometer (XPS) and the calculation of function relationship, can obtain the element composition and chemical state information of specified depth in film layer, and establish the function relationship of X-ray photoelectron spectrometer argon ion sputtering source to the etching rate of corresponding coating of film.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of characterization analysis, and more particularly to a method for measuring etching rate of a thin film layer. BACKGROUND

[0002] X-ray photoelectron spectrometer (XPS) is a commonly used surface analysis instrument, which is very sensitive to the element composition and chemical state of 3-10 nm of the material surface. The basic principle is: a beam of high-energy X-ray photons is used to bombard the outer electrons of the atoms on the surface of the solid sample, so that the electrons escape from the bondage to the vacuum and are collected and detected. The binding energy of the atomic nucleus to the electron is calculated indirectly according to the kinetic energy of the escaping electron, and then the element composition and chemical valence state of the sample are analyzed.

[0003] XPS is usually a non-destructive detection method. When scientific research and process production need to analyze the composition and chemical state of deep samples, argon ion etching technology is introduced to clean the surface of the sample, and then XPS is used for characterization analysis. At this time, the depth information is uncertain. Although the XPS instrument database gives the etching rate corresponding to different conditions of Ta2O5 material, the hardness of different materials has a significant difference, and the depth information cannot be determined by this. Due to the uncertainty of the etching rate, the element composition and chemical valence state information of the accurate depth of the thin film layer cannot be obtained.

[0004] Therefore, how to provide a method for measuring the etching rate of a thin film layer is a problem that those skilled in the art need to solve. SUMMARY

[0005] Therefore, the purpose of the present application is to provide a method for measuring the etching rate of a thin film layer to solve the problems in the prior art.

[0006] In order to achieve the above purpose, the present application adopts the following technical solutions:

[0007] A method for measuring the etching rate of a thin film layer, specifically comprising the following steps:

[0008] (1) Attaching one or more coatings on a support layer substrate with known composition to form a thin film, determining the pore size, number of coatings, composition of each coating and main purpose of the film, and finding the characteristic elements of each coating;

[0009] (2) Accurately obtaining the thickness value of each coating by observing and measuring the film cross section through field emission scanning electron microscope, and obtaining the characteristic elements of each coating by scanning and analyzing the surface distribution of the film cross section through the energy spectrometer attached to the field emission scanning electron microscope;

[0010] (3) Adopting X-ray photoelectron spectrometer to analyze the film, obtaining the composition and chemical state information of the most surface layer elements as reference data;

[0011] (4) Setting etching program, determining the etching area, etching mode and etching energy of argon ion source, and opening argon ion gun to clean and etch the film;

[0012] (5) After etching at different times, adopting X-ray photoelectron spectrometer to collect spectrum, when different element characteristic peaks appear in two groups of data results, recording the etching time, etching area, etching mode and etching energy;

[0013] (6) Through the determined thickness of the film and the recorded etching parameters, establishing the function relationship of the etching rate of the X-ray photoelectron spectrometer argon ion sputtering source to the corresponding coating of the thin film.

[0014] Further, in the above step (1), the film is a commercial filter membrane, which has many advantages, such as high pore size accuracy, can remove most colloids and suspended solids, long service life, low operating cost, etc. The thickness of the film directly affects the filtering capacity and production cost, and the quality inspection work of the film thickness is also a key link of the production company.

[0015] Further, in the above step (2), the field emission scanning electron microscope uses the secondary electron signal grating scanning point-by-point imaging obtained after a beam of high-energy electrons bombarding the sample to obtain the topographic information of the sample, and confirms the accurate thickness of the film sample; the characteristic X-ray generated by the high-energy electron beam bombarding the sample is used for energy spectrum analysis, and the characteristic elements of each coating are found. This step is not only the verification of the film thickness and composition, but also the data guarantee for the subsequent etching rate calculation.

[0016] Further, in the above step (3), the operation of adopting X-ray photoelectron spectrometer to analyze the film is as follows: first, place the film in the pre-evacuation chamber of the X-ray photoelectron spectrometer to evacuate, and then send the sample stage into the analysis chamber for analysis. Further, the evacuation time is 6-8h, and the vacuum degree reaches 10 -8 mbar.

[0017] The beneficial effects of the above further technical solutions are that the film is analyzed by XPS, and since the film sample is exposed to air during the transfer process, the most surface layer may undergo oxidation reaction, so the obtained result information is not the element composition and chemical state of the real outer film. At this time, the obtained result is only used as a reference.

[0018] Further, in the step (4), the high-purity argon gas directly enters the ion gun system, the filament is heated to release electrons, and after acceleration, the electrons collide with the gas atoms, taking away the negative electrons, leaving the positive argon ions, and after acceleration, forming an argon ion beam. Selecting different energy and mode will cause different condenser energy values, and the etching area should be greater than the spot diameter in the XPS test to ensure that the same depth data results are obtained.

[0019] Further, in the step (4), the etching area is 2-3 times the selected spectrum acquisition area of the X-ray photoelectron spectrometer.

[0020] The beneficial effects of the above further technical solutions are that the etching area is determined, and the XPS spectrum acquisition area is a circle with a diameter D, wherein D is a fixed value in the range of 20-900 μm, and to ensure the consistency of the depth of the spectrum acquisition area, the etching area is set to be 2-3 times the selected spectrum acquisition area.

[0021] Further, in the step (4), the etching mode is a single atom ion gun mode.

[0022] The beneficial effects of the above further technical solutions are that the etching mode is determined, and the argon ion source is equipped with single atom and cluster modes, wherein the etching rate of the cluster ion gun is very low, and is used for extremely sensitive materials, and the single atom ion gun mode is selected in the present application to increase the etching efficiency. The single atom ion gun can change the diameter of the ion beam through the focusing effect of the electromagnetic lens to form low and high modes, which are abbreviated as low and high, respectively.

[0023] Further, in the step (4), the etching energy is 500-4000 ev, preferably 500 ev, 1000 ev, 2000 ev, 3000 ev or 4000 ev.

[0024] The beneficial effects of the above further technical solutions are that the etching energy is further determined, and the etching efficiency will increase accordingly as the energy increases.

[0025] Further, in the step (5), as the etching time is prolonged, the composition and chemical state information of the deep layer of the film will be collected and analyzed by XPS, and there will be obvious characteristic element spectrum peak differences at the interface between the coatings, at which time the etching time, the energy, the mode and the area of the argon ion source used are recorded.

[0026] According to the above technical solutions, compared with the prior art, the beneficial effects of the present application are as follows:

[0027] 1. The film layer used in the application is composed of a support layer and a coating layer, has the characteristics of light weight, high strength and aging resistance, and can be widely used in the fields of construction, medicine and pure water filtration, and sterile experiments.

[0028] 2. The application mainly uses argon ion beam to bombard the surface of the film layer, and then through X-ray photoelectron spectrometer (XPS) and function relationship calculation, the element composition and chemical state information of the specified depth in the film layer can be obtained, and the function relationship of the etching rate of the X-ray photoelectron spectrometer argon ion sputtering source to the corresponding coating of the film is established.

[0029] 3. The application is beneficial to explore the material properties at the interface of the specified thickness layer in the film layer of the same material, and provides a new solution for the field of film analysis. DETAILED DESCRIPTION

[0030] Figure 1 Figure 1 is a film sample morphology information diagram obtained by a field emission scanning electron microscope in step (2) of embodiment 1;

[0031] Figure 2 Figure 2 is an element composition and chemical state information diagram of the surface layer in step (3) of embodiment 1;

[0032] Figure 3 Figure 3 is a data result diagram after argon ion etching in step (4) of embodiment 1. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the application will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0034] Embodiment 1

[0035] The method for measuring the etching rate of the film layer specifically includes the following steps:

[0036] (1) A film is formed by attaching one or more coating layers on a support layer substrate with known composition, the pore size, the number of coating layers, the composition of each coating layer and the main purpose of the film are determined, and the characteristic elements of each coating layer are found out;

[0037] (2) The thickness value of each coating layer is accurately obtained by observing and measuring the film section through a field emission scanning electron microscope, and the characteristic elements of each coating layer are accurately obtained by surface distribution scanning analysis of the film section through an energy spectrometer attached to the field emission scanning electron microscope;

[0038] (3) First, the film is placed in the X-ray photoelectron spectrometer pre-evacuation chamber for 6-8 hours to a vacuum degree of 10 -8 mbar, and then the sample stage is sent into the analysis chamber for analysis to obtain the composition and chemical state information of the topmost layer elements as reference data;

[0039] (4) Set the etching program to determine the etching area, etching mode and etching energy of the argon ion source, wherein the X-ray photoelectron spectrometer selects a spectrum collection area of 500 μm, the set etching area is 1.5 mm, the etching mode is a single atom ion gun mode, the etching energy is 2000 ev, and finally the argon ion gun is turned on to clean and etch the film;

[0040] (5) After etching for different times, the X-ray photoelectron spectrometer is used to collect spectra, and when different element characteristic peaks appear in the two sets of data results, the etching time, etching area, etching mode and etching energy are recorded;

[0041] (6) Through the determined thickness of the film and the recorded etching parameters, the function relationship of the etching rate of the X-ray photoelectron spectrometer argon ion sputtering source on the corresponding coating of the thin film is established.

[0042] Example 2

[0043] The method for measuring the etching rate of the thin film layer specifically includes the following steps:

[0044] (1) Attach one or more coatings on a support layer substrate with known composition to form a thin film, and determine the pore size, number of coatings, composition and main purpose of each coating, and find the characteristic elements of each coating;

[0045] (2) Accurately obtain the thickness value of each coating by observing and measuring the film cross section through the field emission scanning electron microscope, and obtain the characteristic elements of each coating by scanning and analyzing the surface distribution of the film cross section through the energy spectrometer attached to the field emission scanning electron microscope;

[0046] (3) First, the film is placed in the X-ray photoelectron spectrometer pre-evacuation chamber for 6-8 hours to a vacuum degree of 10 -8 mbar, and then the sample stage is sent into the analysis chamber for analysis to obtain the composition and chemical state information of the topmost layer elements as reference data;

[0047] (4) Set the etching program to determine the etching area, etching mode and etching energy of the argon ion source, wherein the X-ray photoelectron spectrometer selects a spectrum collection area of 500 μm, the set etching area is 1.5 mm, the etching mode is a single atom ion gun mode, the etching energy is 500 ev, and finally the argon ion gun is turned on to clean and etch the film;

[0048] (5) After etching at different times, X-ray photoelectron spectrometer is used to collect spectrum, and when different element characteristic peaks appear in two groups of data results, the etching time, etching area, etching mode and etching energy are recorded;

[0049] (6) Through the determined thickness of the film and the recorded etching parameters, the function relationship of the etching rate of the X-ray photoelectron spectrometer argon ion sputtering source to the corresponding coating of the thin film is established.

[0050] Example 3

[0051] The method for measuring the etching rate of the thin film layer specifically comprises the following steps:

[0052] (1) Attach one or more coatings on a support layer substrate with known composition to form a thin film, and determine the pore size, the number of coatings, the composition and the main purpose of each coating, and find out the characteristic elements of each coating;

[0053] (2) Accurately obtain the thickness value of each coating by observing and measuring the film cross section through the field emission scanning electron microscope, and obtain the characteristic elements of each coating by scanning and analyzing the surface distribution of the film cross section through the energy spectrometer attached to the field emission scanning electron microscope;

[0054] (3) First, place the film in the X-ray photoelectron spectrometer pre-evacuation chamber for 6-8 hours to reach a vacuum degree of 10 -8 mbar, and then send the sample stage into the analysis chamber for analysis to obtain the composition and chemical state information of the surface elements as reference data;

[0055] (4) Set the etching program to determine the etching area, etching mode and etching energy of the argon ion source, wherein the X-ray photoelectron spectrometer selects the spectrum collection area of 500μm, sets the etching area of 1.0mm, the etching mode of single atom ion gun mode, and the etching energy of 4000ev, and finally opens the argon ion gun to clean and etch the film;

[0056] (5) After etching at different times, X-ray photoelectron spectrometer is used to collect spectrum, and when different element characteristic peaks appear in two groups of data results, the etching time, etching area, etching mode and etching energy are recorded;

[0057] (6) Through the determined thickness of the film and the recorded etching parameters, the function relationship of the etching rate of the X-ray photoelectron spectrometer argon ion sputtering source to the corresponding coating of the thin film is established.

[0058] Performance test

[0059] 1, The film sample morphology information obtained by the field emission scanning electron microscope in step (2) of example 1 is shown in the following figure: Figure 1

[0060] ​From Figure 1 It can be seen that the accurate thickness of the film sample can be further confirmed by the topographic information of the film sample.

[0061] 2. The composition and chemical state information of the most surface layer elements in step (3) of Example 1 are shown in Table 2. Figure 2

[0062] From Figure 2 It can be seen that the characteristic elements of the surface layer show obvious peak shape, and the characteristic elements of other layers show a baseline at this time.

[0063] 3. In step (4) of Example 1, after the etching program parameters are determined, the program is started and the etching time is recorded. The same time interval can be set for etching and then for spectrum collection, so that the depth profiling data results can be obtained. When the characteristic elements of the thin film coating appear in the peak shape in a certain group of data in the depth profiling results, the etching time of the coating can be determined. The results are shown in Table 3. Figure 3

[0064] From Figure 3 It can be seen that the etching energy of the thin film coating is 2000ev, the single atom high mode, and the time is 750s. After etching, the oxygen element in the coating has disappeared, which is the interface layer between the coating and the support layer.

[0065] The above description of disclosed embodiments enables one of ordinary skill in the art to make or use the application. Various modifications to these embodiments will be readily apparent to those of ordinary skill in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Accordingly, the application is not to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.​​

Claims

1. A method for determining the etching rate of a thin film layer, characterized in that, Specifically comprising the following steps: (1) attaching one or more coating layers on a support layer substrate with known composition to form a thin film, determining the pore size of the film, the number of coating layers, the composition of each coating layer and the main purpose, and finding out the characteristic elements of each coating layer; (2) observing and measuring the film cross section by field emission scanning electron microscope to accurately obtain the thickness value of each coating layer; by scanning and analyzing the surface distribution of the film cross section by the energy spectrometer attached to the field emission scanning electron microscope, the characteristic elements of each coating layer are accurately obtained; (3) using X-ray photoelectron spectrometer to analyze the film to obtain the composition and chemical state information of the surface layer elements as reference data; (4) setting etching program, determining the etching area, etching mode and etching energy of argon ion source, and opening argon ion gun to clean and etch the film; The etching area is 2-3 times the selected spectrum collection area of the X-ray photoelectron spectrometer; The etching mode is single atom ion gun mode; The etching energy is 500-4000 ev; (5) after etching for different time, using X-ray photoelectron spectrometer to collect spectrum, when two groups of data results appear different element characteristic peaks, recording etching time, etching area, etching mode and etching energy; (6) through the determined thickness of the film and the recorded etching parameters, the function relationship of the etching rate of the X-ray photoelectron spectrometer argon ion sputtering source to the corresponding coating layer of the thin film is established.

2. The method of claim 1, wherein the film layer is a silicon oxide film layer. In step (3), the operation of analyzing the film by X-ray photoelectron spectrometer is specifically: first, place the film in the pre-evacuation chamber of the X-ray photoelectron spectrometer for vacuum pumping, then send the sample stage into the analysis chamber for analysis.

3. The method of claim 2, wherein the film layer is a silicon oxide layer. The time of the vacuuming is 6-8 h, until the vacuum degree reaches 10 -8 mbar.

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