CN110345889A - A method of utilizing energy spectrum analysis non-destructive testing sample film thickness - Google Patents

Abstract

The invention discloses a kind of methods using energy spectrum analysis non-destructive testing sample film thickness, using the film layer of heterogeneity in the case where accelerating electron bombardment, the principle of different characteristic X-ray can be excited, acceleration electron bombardment is carried out to mark block, the corresponding relationship standard curve between film layer characteristic element and film thickness is made, the intensity and frequency for carrying out the X-ray obtained after acceleration electron bombardment to sample to be tested is then analyzed, obtains the content of element, contrast standard curve, calculates thicknesses of layers.The present invention is only with common scanning electron microscope and energy disperse spectroscopy, it is put into without the additional special ancillary equipment of detection and accessory, it is at low cost and easy to operate, suitable in nanometer and micron range, inorganic non-metallic, macromolecule and all kinds of film layers of metal, the film thickness for being suitable for single layer, bilayer and sandwich diaphragm layer simultaneously detects, applied widely, and will not damage to sample.

Description

A method for non-destructive testing of sample film thickness using energy spectrum analysis

technical field

The invention relates to the technical field of film thickness detection, in particular to a method for nondestructively detecting the film thickness of a sample by using energy spectrum analysis.

Background technique

At present, in actual production and life, in order to ensure the stable and long-term effective use of the product, it is usually necessary to cover the surface of the material, such as anodizing, painting, electroplating/electroless plating, PVD/CVD, etc. The common functions of these surface coating layers are beautification of appearance, improvement of product wear resistance, improvement of product corrosion resistance, and change of product electromagnetic properties.

In order to ensure the normal realization of the function of the film layer, it is necessary to ensure that the film layer has a certain thickness. Common film thickness detection methods include slice method, Coulomb method, magnetic method, X-ray method, β-ray method, etc. Among them, the slicing method and the Coulomb method are destructive tests, which can damage the test samples. The magnetic method is only suitable for the detection of the thickness of the magnetic material film layer, and the X-ray method is only used for the detection of the metal layer composition on the metal and some plastic substrates. The beta-ray method is similar to the X-ray method, but the radiation is relatively large and is currently used less and less. The above detection methods generally require additional special detection auxiliary equipment, and the application range is small.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a method for non-destructive testing of sample film thickness using energy spectrum analysis, which can be used in nanometer and micrometer scales, inorganic non-metallic, polymer and metal film layers, single-layer, double-layer or The film thickness detection of the three-layer composite film layer does not require additional testing auxiliary equipment, the operation is simple, and it is non-destructive to the sample, and has a wide range of applications.

The technical scheme adopted in the present invention is: a method for nondestructively detecting the film thickness of a sample by using energy spectrum analysis, comprising the following steps:

a. Prepare several target blocks, scanning electron microscopes and energy dispersive spectrometers with different film thicknesses and the film thicknesses are in the range of nanoscale to micrometer scale, and the target block and the sample to be tested are of the same substance;

b. Use the accelerated electrons with the specified working parameters in the scanning electron microscope to bombard all the target blocks respectively to generate energy spectrum signals, that is, characteristic X-rays. The detector of the energy spectrometer receives the signals and analyzes the elements of the film layer on the target blocks. content;

c. According to the content of different constituent elements obtained from the blocks with different film thicknesses, select the content of a main characteristic element, obtain the corresponding relationship between the film thickness and the main characteristic element content of the film layer, formulate a standard curve, and map the corresponding Relationships and standard curves are recorded in the database;

d. Use accelerated electrons with the same working parameters as above to bombard the surface of the sample to generate energy spectrum signals, and the detector of the energy spectrometer receives the signals and analyzes the content of each constituent element;

e. According to the measured content of each constituent element, select the same element as the above-mentioned main characteristic element, and compare its content with the standard curve to obtain the film thickness of the sample.

Preferably, in the step a, the thickness of the target block is 1 nm-5 μm.

Preferably, in the step a, there are no less than three target blocks.

Preferably, in the step b, the specified working parameters include electron acceleration voltage 5KV-30KV, working distance 5mm-30mm, image magnification 30-300,000 times and energy spectrum scanning time 5s-150s.

The beneficial effects of the present invention are as follows: the present invention utilizes the principle that different characteristic X-rays can be excited under the accelerated electron bombardment of the film layers with different compositions, and the target block is subjected to accelerated electron bombardment to formulate the difference between the characteristic elements of the film layer and the film thickness. Correspondence standard curve, and then analyze the intensity and frequency of the X-ray obtained after the accelerated electron bombardment of the test sample to obtain the element content, compare the standard curve, and calculate the film thickness. This method is suitable for various types of films in the nanometer and micrometer range, inorganic non-metals, polymers and metals. It is also suitable for film thickness detection of single-layer, double-layer and triple-layer composite films. The spectrometer does not require additional accessories, is simple to operate, does not damage the sample, and has a wide range of applications.

Description of drawings

Fig. 1 is the flow chart of the present invention;

2 is a schematic diagram of the sample characteristic X-ray generation process according to the present invention;

3 is a schematic diagram of a standard curve for testing the thickness of the anodic oxide film on the surface of the pure aluminum sample according to the present invention;

4 is a schematic diagram of a standard curve for the thickness test of epoxy resin paint on the surface of a low carbon steel sample according to the present invention;

5 is a schematic diagram of a standard curve for the thickness test of the gold-plated layer on the surface of the pure copper sample according to the present invention;

FIG. 6 is a schematic diagram of a standard curve for testing the thickness of the nickel-plated gold-plated layer on the surface of the pure copper sample according to the present invention.

In the figure: accelerated electron 1, sample 2, characteristic X-ray 3, detector 4.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

As shown in Figure 1, the present invention comprises the following steps:

a. Prepare several target blocks, scanning electron microscopes and energy spectrometers with different film thicknesses and the film thicknesses are in the range of nanometer to micrometer. The target block and the sample to be tested are of the same substance, that is, the target block The film layer and the film layer of the sample to be tested are of the same material, and the difference is only in the thickness of the film layer, which can be confirmed by the slicing method. When selecting the target block, the thickness of the selected target block is 1nm-5μm and not less than three;

b. Use the accelerated electrons 1 of the specified working parameters in the scanning electron microscope to bombard all the target blocks respectively to generate energy spectrum signals, that is, characteristic X-rays 3, and the detector 4 of the energy spectrometer receives the signals and analyzes the film layer on the target block. The content of each constituent element, its use process is shown in Figure 2, the working parameters used are: electron acceleration voltage 5KV-30KV, generally 15KV, working distance 5mm-30mm, generally 15mm, image magnification 30 times-300,000 In actual operation, the selected multiple should include the designated test area, the energy spectrum scanning time is 5s-150s, and the selected scanning time requires sufficient characteristic X-ray 3 acquisition rate to ensure the detection accuracy;

c. According to the content of different constituent elements obtained by the target blocks with different film thicknesses, select the content of a main characteristic element, obtain the corresponding relationship between the film thickness and the content of the main characteristic elements of the film layer, and formulate a standard curve. The more accurate the standard curve obtained, the more accurate the standard curve is, specifically, take the content of the selected main characteristic elements as the abscissa and the film thickness as the ordinate, make a standard curve, and record the corresponding relationship and standard curve in the database;

d. bombard the surface of the sample 2 with accelerated electrons 1 with the same working parameters as above to generate an energy spectrum signal, and the detector 4 of the energy spectrometer receives its signal and analyzes the content of each constituent element;

e. According to the measured content of each constituent element, select the same element as the above-mentioned main characteristic element, and compare its content to the standard curve to obtain the film thickness of the sample, which can be obtained by manual calculation of the corresponding relationship, or by pre-processing. The programming template is automatically calculated.

In the step b, the film layer is a composite of one or more of inorganic non-metal, polymer and metal film layers.

In the step b, the film layer is a single-layer, double-layer or three-layer composite film layer, but each film layer is required to contain different main characteristic elements, and these elements will generate their own characteristic X-rays 3 .

Below in conjunction with embodiment, the technical scheme of the present invention is described in further detail:

Example 1

The thickness of the anodic oxide film on the surface of the pure aluminum sample is tested, which is applied in the field of inorganic non-metallic and is a single-layer film. Its operation process is as follows:

a. Prepare a scanning electron microscope, an energy spectrometer, and several pure aluminum blocks with anodized film layers, and the film thicknesses of these blocks are in the range of 1nm-5μm and the film thickness is different. The target block can be prepared by changing the anode process parameters, and its film thickness can be confirmed by the eddy current method or the ball milling method, and the selected target block is not less than three;

b. Use the accelerated electrons 1 with the specified working parameters in the scanning electron microscope to bombard all the target blocks respectively, and generate the characteristic X-ray 3 signal in the excitation range of the characteristic X-ray, and the detector 4 of the energy spectrometer receives its signal and analyzes the characteristic X-ray The intensity and frequency of 3 can be used to obtain the content of each constituent element of the film on the target block. The use process is shown in Figure 2. As the thickness of the film increases, the characteristic X-ray 3 intensity of the corresponding element of the film will increase, reflecting In order to increase the element content, the working parameters used are: electron acceleration voltage 15KV, working distance 15mm, image magnification 150 times, and energy spectrum scanning time 35s;

c. According to the content of different constituent elements obtained from the standard blocks with different film thicknesses, select the content of the anode characteristic element O element, obtain the corresponding relationship between the film thickness of the anodic oxide film and the content of O element, and formulate a standard curve. The more blocks, the more accurate the standard curve obtained. Specifically, the content of the selected O element is used as the abscissa, and the film thickness of the anodized film is used as the ordinate. As shown in Figure 3, the standard curve is drawn, and the corresponding relationship and standard curve are recorded in the database;

d. Use accelerated electrons 1 with the same working parameters as above to bombard the surface of the pure aluminum sample with anodized film to generate energy spectrum signals. content;

e. According to the measured content of each constituent element, select the content of O element and compare its content with the standard curve to obtain the thickness of the anodic oxide film, which can be obtained by manually calculating the corresponding relationship, or automatically through the pre-programmed template Calculated.

Example 2

Test the thickness of epoxy resin paint on the surface of low carbon steel samples, for the application in the polymer field. The operation steps are basically the same as the above-mentioned steps, and the specific difference is that: the selected target block is low carbon steel coated with epoxy resin paint, the target block can be prepared by changing the parameters of the painting process, and the specific film thickness can be confirmed by the step method; The working parameters of the scanning electron microscope selected when testing the film content of the target block are: acceleration voltage 15KV, working distance 15mm, magnification 50 times, and energy spectrum scanning time 45s. Select the content of characteristic element C and formulate a standard curve reflecting the corresponding relationship between its content and film thickness, as shown in Figure 4, and then use accelerated electrons 1 with the same working parameters to bombard the surface of the sample, within the excitation range of characteristic X-rays The characteristic X-ray 3 signal is generated, the intensity and frequency of the characteristic X-ray 3 are analyzed, and the content of element C is obtained, and the thickness of the epoxy resin paint is obtained by referring to FIG. 4 .

Example 3

The thickness of the nickel-plated gold-plated layer on the surface of the pure copper sample is tested, Au is the surface film layer, Ni is the bottom film layer, which is the application in the metal field, and the film layer is a double-layer film. The operation steps are basically the same as the above-mentioned steps, the specific difference is: first select a pure copper target block with a nickel-plated gold-plated film layer, and the target block is not less than three. The target block can be prepared by the Hull cell experiment, and the specific film thickness It can be confirmed by slicing method; the working parameters of the scanning electron microscope selected when testing the film content of the target block are: acceleration voltage 15KV, working distance 15mm, magnification 300 times, energy spectrum scanning time 50s, according to the characteristic X-ray obtained from the test 3 Signal, analyze the intensity and frequency of the characteristic X-ray 3, obtain the content of Au and Ni elements, and then first formulate the standard curve of the corresponding relationship between the content of Au in the surface film and the thickness of the film, as shown in Figure 5, and then test the Ni content. When the relationship between the content and the film thickness of Ni, in this experiment, three values of Au film thickness of 0.01 μm, 0.05 μm, and 0.4 μm were selected as three groups for testing, and each group had no less than three standard blocks and The thickness of the Ni plating layer is different. Similarly, the standard curve of the corresponding relationship between the content of Ni and the thickness of the Ni layer when the thickness of the Au film layer is 0.01 μm, 0.05 μm and 0.4 μm is shown in Figure 6. Then, the surface of the sample is bombarded with accelerated electrons 1 with the same working parameters, and the thickness of the nickel-plated gold-plated layer is obtained by referring to Fig. 5 and Fig. 6 .

The invention utilizes the principle that different characteristic X-rays are excited under the accelerated electron bombardment of film layers of different compositions, and accelerates electron bombardment on the target block. With the increase of the film layer thickness, the characteristic X-ray intensity of the corresponding element of the film layer will increase , which is reflected in the increase of the element content, and then formulate the standard curve of the corresponding relationship between the characteristic elements of the film layer and the film thickness, and then analyze the intensity and frequency of the X-ray obtained after the accelerated electron bombardment of the test sample to obtain the element content. , compare the standard curve, and calculate the film thickness. The invention only adopts common scanning electron microscope and energy spectrometer, does not need additional investment in special auxiliary equipment and accessories for detection, has low cost and simple operation, and is suitable for inorganic non-metallic, polymer and metal films in the nanometer and micrometer range. It is also suitable for film thickness detection of single-layer, double-layer and three-layer composite film layers, which has a wide range of applications and will not cause damage to the sample.

Claims (4)

1. a method for utilizing energy spectrum analysis nondestructive testing sample film thickness, is characterized in that, comprises the steps: a. Prepare several sets of target blocks, scanning electron microscopes and energy spectrometers with different film thicknesses and the film thicknesses are in the range of nanometer to micrometer scale, and the target block and the sample to be tested are of the same substance; b. Use the accelerated electrons with the specified working parameters in the scanning electron microscope to bombard all the target blocks respectively to generate energy spectrum signals, that is, characteristic X-rays. The detector of the energy spectrometer receives the signals and analyzes the elements of the film layer on the target blocks. content; c. According to the content of different constituent elements obtained from the blocks with different film thicknesses, select the content of a main characteristic element, obtain the corresponding relationship between the film thickness and the main characteristic element content of the film layer, formulate a standard curve, and map the corresponding Relationships and standard curves are recorded in the database; d. Use accelerated electrons with the same working parameters as above to bombard the surface of the sample to generate energy spectrum signals, and the detector of the energy spectrometer receives the signals and analyzes the content of each constituent element; e. According to the measured content of each constituent element, select the same element as the above-mentioned main characteristic element, and compare its content with the standard curve to obtain the film thickness of the sample. 2 . The method for non-destructive testing of sample film thickness by energy spectrum analysis according to claim 1 , wherein in the step a, the thickness of the target block is 1 nm-5 μm. 3 . 3 . The method for non-destructive testing of sample film thickness using energy spectrum analysis according to claim 1 , wherein in the step a, there are no less than three groups of target blocks. 4 . 4. The method according to claim 1, characterized in that: in the step b, the specified working parameters include electron acceleration voltage 5KV-30KV, working distance 5mm-30mm, The image magnification is 30 times-300,000 times and the energy spectrum scanning time is 5s-150s.