JP2018141782A - Method of quantifying deposited contaminants and method of analyzing samples - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable accurate quantification of contaminants deposited on a surface of a sample when analyzing the sample using a transmission electron microscope.SOLUTION: A method of quantifying contaminants deposited on a surface of a sample when analyzing the sample using a transmission electron microscope is provided, the method comprising: a deposition step for irradiating the surface of the sample with an electron beam to allow deposition contaminants originating from hydrocarbon components present in the atmosphere to deposit in an irradiated area; an acquisition step for irradiating the surface of the sample with the electron beam covering the area in which the deposition contaminants deposit in order to acquire a high-angle annular dark-field image; and a quantification step for measuring brightness of the area with the deposited contaminants in the high-angle annular dark-field image to quantify the deposited contaminants from the brightness.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for quantifying contaminated deposits and a sample analysis method.

  In material development, it is important to understand the physical properties of materials in detail to understand the physical properties. In recent years, in order to develop the desired material properties, new materials have often been developed by forming microstructures or forming and processing thin films with functionality on the outermost surface of the sample. ing. In order to analyze the physical properties of such a fine region, a transmission electron microscope is often used (see, for example, Patent Document 1).

  A transmission electron microscope (hereinafter also referred to as TEM), for example, irradiates and transmits an electron beam accelerated at a high voltage to an analysis portion of a sample sliced to a thickness of 100 nm or less, and causes various interactions occurring in the sample. This is an analysis method using the received electron beam. According to TEM, an electron beam is irradiated more narrowly than a scanning electron microscope and analysis with high spatial resolution can be performed, so that the form, crystal structure, composition, chemical state, etc. of the ultrafine region can be analyzed.

  In analysis of a sample by TEM, the sample is placed in a TEM chamber and irradiated with an electron beam. At this time, if a hydrocarbon-based gas exists in the chamber, for example, if it remains in the chamber or is generated from the sample, the carbon component is dissociated from the hydrocarbon component by the electron beam and deposited on the sample surface. Sometimes. When the carbon component is deposited on the surface of the sample, for example, the analysis site of the sample becomes thick, or the irradiated electron beam receives an interaction within the carbon component, so that the transmitted electron beam decreases and the transmitted electron beam. Because unnecessary information is mixed, it becomes impossible to perform highly accurate analysis. Thus, the carbon component causes contamination as a contaminated deposit.

  Therefore, in the sample analysis by TEM, in order to suppress the influence of contamination, the apparatus and the sample are heated, or the source substance of the contaminated deposit is removed from the sample by using plasma. .

JP 2014-240780 A

  In the sample analysis by TEM, it is important to suppress contamination. On the other hand, from the viewpoint of further improving the analysis accuracy, it is also important to grasp the amount of contamination when it occurs. This is because the analysis accuracy can be confirmed by the amount of contamination, for example, the analysis accuracy is high when the amount of contamination is small. However, until now, a method for quantitatively evaluating the amount of deposition has not been established only by determining the presence or absence of contamination based on the presence or absence of contaminated deposits on the sample surface.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique for accurately quantifying contaminated deposits deposited on the surface of a sample when the sample is analyzed with a transmission electron microscope.

According to a first aspect of the invention,
A method for quantifying contaminated deposits deposited on a sample surface when the sample is analyzed with a transmission electron microscope,
A deposition step of irradiating the sample surface with an electron beam and depositing contaminated deposits derived from hydrocarbon components present in the atmosphere on the irradiated region;
An acquisition step of irradiating the surface of the sample with an electron beam so as to include a region where the contaminated deposit is deposited, and acquiring a high-angle annular dark field image;
There is provided a method for quantifying contaminated deposits, comprising: measuring a luminance of a region where the contaminated deposits are deposited in the high-angle annular dark field image, and quantifying the contaminated deposits from the luminance.

According to a second aspect of the present invention, in the first aspect,
In the determination step, a luminance profile is obtained from the high-angle annular dark field image, and a thickness of the contaminated deposit is obtained from a luminance difference between the region where the contaminated deposit is deposited and other regions in the luminance profile.

According to a third aspect of the present invention, in the first or second aspect,
In the acquisition step, the electron beam is irradiated at a lower magnification than in the deposition step.

According to a fourth aspect of the present invention, in any one of the first to third aspects,
In the deposition step, the electron beam is irradiated at a magnification of 100,000 to 1,000,000 times.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects,
In the acquisition step, the electron beam is irradiated at a magnification of 10,000 to 100,000.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects,
The deposition step includes
A first deposition step of irradiating the sample surface with an electron beam to deposit a first contaminated deposit on the sample surface;
And a second deposition step of depositing a second contaminated deposit by irradiating the surface of the sample with an electron beam so as to include an area where the first contaminated deposit is deposited.

According to a seventh aspect of the present invention, in the sixth aspect,
In the second deposition step, the electron beam is irradiated at a lower magnification than in the first deposition step.

According to an eighth aspect of the present invention,
A sample analysis method for analyzing a sample with a transmission electron microscope,
A deposition step of irradiating an electron beam to an area other than the analysis location of the sample, and depositing contaminated deposits derived from hydrocarbon components present in the atmosphere in the irradiated area;
An acquisition step of irradiating the surface of the sample with an electron beam so as to include a region where the contaminated deposit is deposited, and acquiring a high-angle annular dark field image;
A quantification step of measuring a luminance of a region where the contaminated deposit is deposited in the high-angle annular dark field image, and quantifying the contaminated deposit from the luminance;
According to the result of the quantification step, there is provided a sample analysis method including an analysis step of acquiring and analyzing a transmission electron image by irradiating an analysis site on the sample surface with an electron beam.

According to a ninth aspect of the present invention, in the eighth aspect,
In the quantitative determination step, a luminance profile is obtained from the high-angle annular dark field image, and a luminance difference between the region where the contaminated deposit is deposited and other regions in the luminance profile is obtained,
In the analysis step, if the luminance difference is equal to or less than a predetermined value, analysis is performed.

  ADVANTAGE OF THE INVENTION According to this invention, when performing sample analysis with a transmission electron microscope, the contaminated deposit deposited on the sample surface can be quantified accurately.

FIG. 1A is a plan view of a sample surface when a contaminated deposit is deposited on the sample surface, and FIG. 1B includes a region in which the contaminated deposit is deposited in FIG. FIG. 1C illustrates a luminance profile in the arrow direction in FIG. 1B. FIG. 2 is a schematic sectional view of a transmission electron microscope. FIG. 3A is a high-angle annular dark field image after depositing a contaminated deposit on the sample A of the example, and FIG. 3B is a luminance obtained by extracting the luminance in the arrow direction of FIG. Indicates a profile. FIG. 4A is a high-angle annular dark field image after depositing a contaminated deposit on Sample B of the example, and FIG. 4B is a luminance obtained by extracting luminance in the arrow direction of FIG. Indicates a profile. FIG. 5A is a high-angle annular dark field image after depositing a contaminated deposit on the sample C of the example, and FIG. 5B is a luminance obtained by extracting the luminance in the arrow direction of FIG. Indicates a profile.

  Prior to the description of the embodiments of the present invention, knowledge obtained by the present inventor will be described.

  The present inventor has studied means for solving the above-described problems, and has focused on a high-angle annular dark field image that can be obtained by irradiating an electron beam onto a sample in a TEM.

  In the TEM, as shown in FIG. 2, a bright field image (Bright Field Image) is formed by irradiating a sample with an electron beam and detecting a transmission electron beam transmitted through the sample with a CCD camera or a BF detector. BF image) can be acquired. According to the BF image, the part where the diffraction occurs is dark and the part where the diffraction does not occur appears bright, and the lattice defect and film thickness of the sample can be measured. However, since the electron beam that has passed through the sample undergoes various interactions due to the crystal structure, strain, composition, etc. when passing through the sample, the BF image formed by imaging the transmitted electron beam has a complex contrast. It is difficult to interpret the image.

  On the other hand, a high-angle annular dark field is formed by irradiating the sample with a finely focused electron beam, and detecting and imaging a relatively large amount of electron beam that has been scattered through the sample with an annular detector. (High Angle Annual Dark Field) image (hereinafter also referred to as HAADF image) can be acquired.

  In the HAADF image, the higher the atomic number of the atoms constituting the sample, the higher the establishment of an electron beam that passes through the sample and scatters at a high angle. Therefore, the higher the atomic number, the brighter the atomic number. Observed as dark. Further, as the sample becomes thicker, the number of atoms that interact with each other increases, and the amount of electron beams scattered at a high angle increases, so that the thicker part is observed brighter and the thinner part is observed darker. In addition, since the HAADF image is less influenced by the interaction with the sample, a clear contrast can be obtained. In this way, in the HAADF image, the image can be easily interpreted from a simple contrast representing the composition and thickness, and a portion where an atom with a large atomic number is present or the sample is thick is observed relatively brightly. Will be.

  The present inventor further examined and obtained a HAADF image of the sample surface on which the contaminated deposit was deposited and analyzed the contrast, and found that the contaminated deposit could be captured quantitatively. Specifically, in the HAADF image, due to the amount of the carbon component in the transmission direction of the electron beam, that is, the thickness of the contaminated deposit containing the carbon component, It was found that the contrast was changed between the two, and the contaminated deposit could be quantitatively evaluated by the thickness by judging the contrast by the brightness.

  Also, before irradiating the sample analysis site with an electron beam, analysis is performed after depositing and quantifying contaminated deposits in areas other than the sample analysis site, and confirming that contamination is unlikely to occur in the sample. By doing so, it was found that highly accurate analysis can be performed efficiently.

  The present invention has been made based on such findings.

<One Embodiment of the Present Invention>
Hereinafter, a sample analysis method according to an embodiment of the present invention will be described. In the present embodiment, using TEM, the contaminated deposit is deposited in a region other than the analysis portion of the sample to quantify the contaminated deposit, and after the degree of contamination of the sample is grasped, the sample analysis is performed. The sample analysis method of this embodiment includes a preparation process, a deposition process, an acquisition process, a quantitative process, and an analysis process. Each step will be described in detail with reference to FIGS. FIG. 1A is a plan view of a sample surface when a contaminated deposit is deposited on the sample surface, and FIG. 1B includes a region in which the contaminated deposit is deposited in FIG. FIG. 1C illustrates a luminance profile in the arrow direction in FIG. 1B.

(Preparation process)
First, a sample to be analyzed is prepared. The sample is not particularly limited as long as it can be analyzed by TEM. For example, it is possible to use a powder sample embedded in a resin and the resin molded body is sliced to a thickness of, for example, 100 nm or less.

(Deposition process)
Subsequently, the sample is introduced into a TEM vacuum chamber equipped with a HAADF detector. Then, as shown to Fig.1 (a), it scans by irradiating an electron beam to areas other than the analysis location on the surface of the sample 10. FIG. Thereby, the contaminated deposit 11 derived from the hydrocarbon component present in the atmosphere is deposited in the electron beam irradiation region. In addition, the hydrocarbon component which exists in atmosphere shows the component which arises from the sample 10 or remains in the chamber.

  In the deposition process, it is preferable to irradiate the electron beam with a magnification of 100,000 to 1,000,000 times. By irradiating the electron beam at such a magnification, the amount of irradiation per unit area can be increased and the contaminated deposit can be deposited efficiently, so that the contaminated deposit can be accurately quantified.

(Acquisition process)
Subsequently, the imaging region 12 including the region where the contaminated deposit 11 is deposited is determined, and the imaging region 12 is irradiated with an electron beam and scanned. Then, among the electron beams transmitted through the sample 10 and the contaminated deposit 11, an electron beam scattered at a high angle is detected and imaged, and a high angle annular dark field image (HAADF image) as shown in FIG. ) To get. In the HAADF image shown in FIG. 1B, the area where the contaminated deposit 11 containing the carbon component is deposited is observed to be brighter and brighter than other areas where the contaminated deposit 11 is not deposited. That is, a predetermined contrast is obtained between a region where the contaminated deposit 11 is deposited and a region where the contaminated deposit 11 is not deposited.

  In the acquisition process, it is preferable to irradiate the electron beam at a lower magnification than the deposition process from the viewpoint of preventing generation of the contaminated deposit 11 when the electron beam is irradiated. Specifically, it is preferable to irradiate an electron beam with a magnification of 10,000 to 100,000. By setting it to 10,000 times or more, the contaminated deposit can be observed with an appropriate size, and by setting it to 100,000 times or less, redeposition during observation can be suppressed. That is, the contaminated deposit formed in the deposition process can be observed with an appropriate size while suppressing redeposition.

(Quantitative process)
Then, the brightness | luminance of the area | region where the contaminated deposit 11 accumulates is measured about the HAADF image obtained at the acquisition process. In the HAADF image, as the deposition amount (thickness) of the contaminated deposit 11 increases, the area where the contaminated deposit 11 is deposited is observed brighter, and the luminance value increases. Therefore, the amount of the contaminated deposit 11 can be grasped from the luminance value of the region where the contaminated deposit 11 is deposited. For example, the correlation between the thickness of the contaminated deposit 11 and the luminance may be obtained in advance, and the thickness of the contaminated deposit 11 may be calculated from the luminance value obtained from the HAADF image.

  From the viewpoint of quantifying the contaminated deposit with higher accuracy, the luminance profile of the HAADF image is obtained in the quantitative process, and the thickness of the contaminated deposit 11 is determined from the luminance difference between the region where the contaminated deposit 11 is deposited and other regions. It is preferable to determine and quantify the contaminated deposit 11. More specifically, as shown in FIG. 1C, the area where the contaminated deposit 11 is deposited has a high luminance, while the area where it is not deposited has a low luminance. Each luminance value includes thickness information in each region, and the difference in thickness, that is, the thickness of the contaminated deposit 11 can be obtained from the difference in luminance. Note that the luminance profile may be obtained by image analysis of the HAADF image.

(Analysis process)
Subsequently, an analysis process is performed according to the result of the quantitative process. Specifically, the likelihood of contamination of the sample 10 is evaluated based on the result of the quantification process, and if the contamination is small, analysis for specifying the type and amount of the element of the sample 10 is performed. For example, if the brightness difference between the area where the contaminated deposit is deposited and other areas, which correlate with the thickness of the contaminated deposit 11, is less than or equal to a desired value, there is less contamination due to electron beam irradiation, and the desired measurement accuracy can be achieved. It is judged that it is maintained, and the analysis process for specifying the kind and amount of the element is performed as it is after the determination process. In the analysis step, the sample 10 is analyzed by irradiating an analysis site on the surface of the sample 10 with an electron beam to detect a transmission electron beam. On the other hand, if the brightness difference between the area where the contaminated sediment is deposited and the other area exceeds a desired value, the sample 10 is likely to be contaminated by electron beam irradiation, and it is determined that the analysis accuracy cannot be maintained high. The analysis process is not performed. In this case, it is advisable to identify the cause of contamination, review the production conditions of the sample 10, quantify the contamination again, and perform the analysis process. In addition, the numerical value of the luminance difference between the area where the contaminated sediment is deposited and the other area as the evaluation standard for contamination may be changed as appropriate according to the required accuracy. The luminance difference between the area where the deposit is deposited and the other area may be set to a low value.

<Effect according to this embodiment>
According to the present embodiment, the following one or more effects are achieved.

  According to the present embodiment, the HAADF image is acquired after the sample surface is irradiated with the electron beam to deposit the contaminated deposit, and the brightness of the area where the contaminated deposit is deposited is obtained from the HAADF image. The sediment is quantified. Thereby, the amount of contamination when the sample is irradiated with an electron beam can be grasped.

  In addition, a luminance profile is obtained from the HAADF image, and a luminance difference between a region where the contaminated deposit is deposited and other regions is obtained from the luminance profile. Thereby, the thickness of the contaminated deposit can be obtained, and the contaminated deposit can be quantified with higher accuracy.

  In the acquisition process, it is preferable to irradiate the electron beam at a magnification lower than that in the deposition process, the deposition process is preferably 100,000 to 1,000,000 times, and the acquisition process is preferably 10,000 to 100,000 times. By reducing the magnification, the amount of irradiation per unit area when the sample surface is irradiated with an electron beam can be reduced to suppress the formation of contaminated deposits. That is, in the deposition process, the contaminated deposit is efficiently generated by irradiating the electron beam at a relatively high magnification. On the other hand, in the acquisition process, the generation of the HAADF image is not hindered by suppressing the generation of the contaminated deposit. Can be.

  Further, according to the present embodiment, the amount of contamination of the sample is grasped in the determination step, and the analysis step is performed based on the result. In other words, in the case of a sample that has been confirmed to have low contamination in the quantitative process (the difference in luminance between the region where the contaminated deposit is deposited and the other region is small, or the contaminated deposit 11 is thin), an electron is directly applied to the analysis location. It is possible to analyze with high accuracy by irradiating the line. On the other hand, in the case of a sample that has been confirmed to have a large amount of contamination, it is preferable to analyze the sample by identifying the cause of contamination without analyzing it. Thereby, a highly accurate analysis can be performed efficiently.

<Other embodiments>
Although one embodiment of the present invention has been described above, the present invention is not limited to the embodiment described above, and various modifications can be made without departing from the scope of the present invention.

  In the above-described embodiment, the case where the electron beam irradiation is performed once in the deposition process to deposit one layer of the contaminated deposit has been described. However, the electron beam irradiation is performed twice to stack two layers of the contaminated deposit. Is preferred. Specifically, as the first deposition step, the sample surface is irradiated with an electron beam to deposit a first contaminated deposit on the sample surface, and as the second deposition step, the region where the first contaminated deposit is deposited. It is preferable to deposit the second contaminated deposit so as to cover the first contaminated deposit by irradiating the sample surface with an electron beam so as to contain the first contaminated deposit. At this time, it is preferable to irradiate the electron beam at a lower magnification in the second deposition step than in the first deposition step. Thus, by stacking the contaminated deposits twice at a high magnification and a low magnification, it is possible to grasp the easiness of deposition at each magnification for the sample.

  Hereinafter, the present invention will be described based on further detailed examples, but the present invention is not limited to these examples.

(Example)
First, a powder sample and a two-component curable epoxy resin are mixed and cured to form a resin molded body in which the powder sample is embedded in the resin. The resin molded body was sliced using a focused ion processing apparatus (“FB-2100” manufactured by Hitachi High-Technologies Corporation), and a TEM thin sample (hereinafter also simply referred to as a sample) having a thickness of 100 nm or less was produced. did. In this example, three types of sample A, sample B, and sample C were prepared using three types of commercially available two-component curable epoxy resins.

  Subsequently, the sample A was introduced into a transmission electron microscope (“JEM-ARM200F” manufactured by JEOL Ltd.), and HAADF image observation was performed. Specifically, first, the surface of the sample A was scanned by irradiating an electron beam (first irradiation) at a magnification of 1,000,000, a number of pixels of 1000 × 1000, and 30 seconds / frame. Next, the surface of the sample A is scanned by irradiating an electron beam (second irradiation) at a magnification of 500,000, a number of pixels of 1000 × 1000, and 30 seconds / frame so as to include the first irradiation region. did. Finally, the surface of the sample A is scanned by irradiating with an electron beam at a magnification of 100,000 times, a pixel number of 1000 × 1000, 30 seconds / frame so as to include the second irradiation region, A HAADF image as shown in FIG. Further, the HAADF image of FIG. 3A was read by analysis software (“Digital Micrograph” manufactured by GATAN Co., Ltd.) to obtain a luminance profile shown in FIG. FIG. 3B shows a luminance profile in which luminance is extracted in the direction of the arrow in FIG. 3A, and the horizontal axis is the distance [nm] from the starting point of the arrow and the vertical axis is the luminance (intensity) It is a thing.

As shown in FIG. 3 (a), in the HAADF image of the sample A, irradiated areas twice by the first irradiation and second irradiation brightest (R ₁ region in the figure), once the second irradiation irradiation region is followed bright (R ₂ region in the figure), any region that is not irradiated even (R ₃ region in the drawing) it was observed dark. For this reason, the R ₁ region where the amount of irradiation (number of irradiations) of the electron beam is larger, the more contaminated deposits are observed, and the luminance is higher and brighter.
According to FIG.3 (b), it can confirm that the brightness | luminance is changing so as to correspond to the light and darkness of Fig.3 (a). The luminance difference between the brightest R ₁ region and the darkest R ₃ region corresponds to the thickness of the contaminated deposit, and the greater the luminance difference, the thicker the contaminated deposit. Sample A has a brightness difference of about 1 million, and a thick contaminated deposit is formed. It was found that contamination due to electron beam irradiation is likely to occur. That is, according to the sample A, even if a transmission electron image is acquired by irradiating an electron beam as it is, there is a possibility that there is much contamination and the analysis cannot be performed accurately.

  As for Sample B and Sample C, HAADF images were obtained in the same manner as Sample A, and a luminance profile was obtained. 4A is a HAADF image for the sample B, and FIG. 4B shows a luminance profile obtained by extracting the luminance in the arrow direction of FIG. FIG. 5A is a HAADF image for the sample C, and FIG. 5B shows a luminance profile in which luminance is extracted in the direction of the arrow in FIG.

As shown in FIGS. 4A and 4B, the sample B has a smaller brightness difference between the brightest R ₁ region and the darkest R ₃ region than the sample A. It was confirmed that it was thin and the amount of contamination was small.
Further, as shown in FIG. 5 (a) and (b), Sample C, little luminance difference between R ₁ region of R ₃ areas, it does not occur contamination compared to Sample A and Sample B It was confirmed.
From this, it can be seen that Sample B and Sample C have little contamination when irradiated with an electron beam, so that a transmission electron image can be acquired and analyzed with high accuracy.

  As described above, the HAADF image is acquired by depositing the contaminated deposit on the sample surface, and the amount of the contaminated deposit, that is, the amount of contamination can be grasped from the luminance of the region where the contaminated deposit is deposited. In addition, the amount (thickness) of the contaminated deposit can be quantified from the luminance difference between the region where the contaminated deposit is accumulated and observed most brightly and the region where the contaminated deposit is not observed accumulated darkest. .

10 Sample 11 Contaminated sediment 12 Imaging region

Claims (9)

A method for quantifying contaminated deposits deposited on a sample surface when the sample is analyzed with a transmission electron microscope,
A deposition step of irradiating the sample surface with an electron beam and depositing contaminated deposits derived from hydrocarbon components present in the atmosphere on the irradiated region;
An acquisition step of irradiating the surface of the sample with an electron beam so as to include a region where the contaminated deposit is deposited, and acquiring a high-angle annular dark field image;
A quantification step of measuring a luminance of a region in which the contaminated deposit is deposited in the high-angle annular dark field image, and quantifying the contaminated deposit from the luminance; In the quantification step, a luminance profile is obtained from the high-angle annular dark field image, and the thickness of the contaminated deposit is obtained from a luminance difference between a region where the contaminated deposit is deposited and other regions in the luminance profile.
The method for quantifying contaminated sediment according to claim 1. In the acquisition step, the electron beam is irradiated at a lower magnification than the deposition step.
The method for quantifying contaminated deposits according to claim 1 or 2. In the deposition step, the electron beam is irradiated at a magnification of 100,000 times to 1 million times.
The quantification method of the contaminated deposit of any one of Claims 1-3. In the acquisition step, the electron beam is irradiated at a magnification of 10,000 to 100,000 times.
The quantification method of the contaminated deposit of any one of Claims 1-4. The deposition step includes
A first deposition step of irradiating the sample surface with an electron beam to deposit a first contaminated deposit on the sample surface;
A second deposition step of irradiating the surface of the sample with an electron beam so as to include a region where the first contaminated deposit is deposited, and depositing a second contaminated deposit.
The quantification method of the contaminated deposit of any one of Claims 1-5. In the second deposition step, the electron beam is irradiated at a lower magnification than in the first deposition step.
The method for quantifying a contaminated deposit according to claim 6. A sample analysis method for analyzing a sample with a transmission electron microscope,
A deposition step of irradiating an electron beam to an area other than the analysis location of the sample, and depositing contaminated deposits derived from hydrocarbon components present in the atmosphere in the irradiated area;
An acquisition step of irradiating the surface of the sample with an electron beam so as to include a region where the contaminated deposit is deposited, and acquiring a high-angle annular dark field image;
A quantification step of measuring a luminance of a region where the contaminated deposit is deposited in the high-angle annular dark field image, and quantifying the contaminated deposit from the luminance;
An analysis step of acquiring and analyzing a transmission electron image by irradiating an analysis site on the sample surface with an electron beam according to a result of the quantification step. In the quantitative determination step, a luminance profile is obtained from the high-angle annular dark field image, and a luminance difference between the region where the contaminated deposit is deposited and other regions in the luminance profile is obtained,
The sample analysis method according to claim 8, wherein in the analysis step, analysis is performed if the luminance difference is equal to or less than a predetermined value.